ENVIRONMENTAL ASSESSMENT

Construction of Mgongola Irrigation Scheme

Engineering Services for the Tanzania Irrigation and Rural

Roads Infrastructure Project (IRRIP1)

September 2015 – Final

This publication was produced for review by the United States Agency for International Development.
It was prepared by CDM International Inc. for the Irrigation and Rural Roads Infrastructure Project
(IRRIP1), Task Order 03, under the USAID Global A&E IQC (Contract No.: EDH-I-00-08-00023-00).
ENVIRONMENTAL ASSESSMENT
Construction of Mgongola Irrigation Scheme

Engineering Services for the Tanzania Irrigation and

Rural Roads Infrastructure Project (IRRIP1)

Prepared by: Lane Krahl, Environmental Impact Specialist and

Keith F. Williams, P.E., Chief of Party
Organization: CDM International, Inc. (CDM Smith)
Submitted to: Boniphace Marwa, United States Agency for International Development
(USAID) Contracting Officer’s Representative (COR)
USAID Contract No.: EDH-I-00-08-00023-00, Task Order #3
Report Date: September 8, 2015

DISCLAIMER
The authors’ views expressed in this publication do not necessarily reflect the views
of the United States Agency for International Development or the United States
Government.
TABLE OF CONTENTS
1 SUMMARY..................................................................................................................... 1-1

1.1 Purpose and Need ............................................................................................. 1-1

1.2 Alternatives......................................................................................................... 1-3
1.2.1 Proposed Action .................................................................................. 1-3
1.2.2 Piped Main Canal Alternative .............................................................. 1-4
1.2.3 Sprinkler Irrigation Alternative ............................................................. 1-4
1.2.4 SRI Alternative ..................................................................................... 1-4
1.2.5 Improved Intensified Rain-Fed Agriculture Alternative ........................ 1-4
1.2.6 No Action Alternative ........................................................................... 1-5
1.3 Major Conclusions .............................................................................................. 1-5
1.4 Preferred Alternative .......................................................................................... 1-6
1.5 Areas of Controversy and the Issues to be Resolved ........................................ 1-6

2 INTRODUCTION............................................................................................................ 2-1

3 PURPOSE OF THE PROPOSED ACTION ................................................................... 3-1

3.1 Purpose of Feed the Future ............................................................................... 3-1

3.2 Purpose of IRRIP1 ............................................................................................. 3-1
3.3 Purpose of the Construction of the Mgongola Irrigation Scheme ....................... 3-1
3.4 Need to Which the Project Is Responding.......................................................... 3-2
3.4.1 Location ............................................................................................... 3-2
3.4.2 Background ......................................................................................... 3-3
3.4.3 Existing Agricultural Practices in the Project Area ............................... 3-6

4 ALTERNATIVES............................................................................................................ 4-8

4.1 The Proposed Action .......................................................................................... 4-8

4.1.1 General Construction Activities ......................................................... 4-10
4.1.2 Irrigation and Drainage Components ................................................. 4-12
4.1.3 Flood Protection ................................................................................ 4-17
4.1.4 Farm Roads ....................................................................................... 4-17
4.1.5 Demobilization ................................................................................... 4-18
4.1.6 Operation, Maintenance and Management ....................................... 4-18
4.1.7 Cropping ............................................................................................ 4-19
4.1.8 Irrigation Water Requirements and Water Rights .............................. 4-20
4.2 Piped Main Canal Alternative ........................................................................... 4-20
4.2.1 Irrigation and Drainage Components ................................................. 4-21
4.2.2 Operation, Maintenance and Management ....................................... 4-21
4.2.3 Irrigation Water Requirements and Water Rights .............................. 4-22
4.3 Sprinkler Irrigation Alternative .......................................................................... 4-22
4.3.1 Irrigation and Drainage Components ................................................. 4-22
4.3.2 Operation, Maintenance and Management ....................................... 4-23

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 4.3.3 Cropping ............................................................................................ 4-24
4.3.4 Irrigation Water Requirements and Water Rights .............................. 4-24
4.4 SRI Alternative ................................................................................................. 4-24
4.4.1 Operation, Maintenance and Management ....................................... 4-25
4.4.2 Cropping ............................................................................................ 4-26
4.4.3 Irrigation Water Requirements and Water Rights .............................. 4-27
4.5 Improved Intensified Rain-Fed Agriculture Alternative ..................................... 4-28
4.6 No Action Alternative ........................................................................................ 4-28
4.7 Alternatives Eliminated from Analysis .............................................................. 4-28
4.7.1 Full Sprinkler Irrigation with Central Pumping ................................... 4-29
4.8 Mitigation Measures ......................................................................................... 4-29
4.9 Comparison of Environmental Impacts of Alternatives ..................................... 4-31
4.10 Preferred Alternative ........................................................................................ 4-34

5 AFFECTED ENVIRONMENT ........................................................................................ 5-1

5.1 Boundaries ......................................................................................................... 5-1

5.2 Physical Environment ......................................................................................... 5-2
5.2.1 Topography ......................................................................................... 5-2
5.2.2 Geology and Soils ............................................................................... 5-2
5.2.3 Climatic Conditions .............................................................................. 5-3
5.2.4 Water Resources ................................................................................. 5-5
5.2.5 Air and Noise ..................................................................................... 5-12
5.3 Biological Environment ..................................................................................... 5-12
5.3.1 Vegetation ......................................................................................... 5-12
5.3.2 Wildlife ............................................................................................... 5-14
5.3.3 Protected Areas ................................................................................. 5-14
5.4 Socio-Economic Environment .......................................................................... 5-14
5.4.1 Administrative Boundaries ................................................................. 5-15
5.4.2 Demographic Characteristics ............................................................ 5-15
5.4.3 Land Use ........................................................................................... 5-15
5.4.4 Land Ownership and Tenure ............................................................. 5-16
5.4.5 Economic Activities ............................................................................ 5-18
5.4.6 Income and Expenditure .................................................................... 5-19
5.4.7 Water, Sanitation and Solid Waste Disposal ..................................... 5-20
5.4.8 Health ................................................................................................ 5-20
5.4.9 Energy ............................................................................................... 5-20
5.4.10 Transport and Communication .......................................................... 5-20
5.4.11 Vulnerable Groups ............................................................................. 5-21
5.4.12 Capacity of the WUA ......................................................................... 5-21

6 ENVIRONMENTAL CONSEQUENCES ........................................................................ 6-1

6.1 Results of Scoping ............................................................................................. 6-1

6.2 Impacts Common to All Irrigation Alternatives ................................................... 6-1

ENVIRONMENTAL ASSESSMENT
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 6.2.1 Impacts During Mobilization and Construction .................................... 6-1
6.2.2 Impacts During Operation .................................................................... 6-4
6.3 Impacts of Improved Intensified Rain-Fed Agriculture Alternative ................... 6-17
6.3.1 Impacts During Mobilization and Construction .................................. 6-17
6.3.2 Impacts During Operation .................................................................. 6-17
6.4 Impacts of No Action ........................................................................................ 6-18
6.5 Significant Impacts ........................................................................................... 6-18
6.6 Irreversible or Irretrievable Commitments of Resources .................................. 6-19
6.7 Possible Conflicts with Land Use Plans, Policies and Controls for the Area .... 6-19
6.8 Cumulative Impacts .......................................................................................... 6-19

7 ENVIRONMENTAL MITIGATION AND MONITORING ................................................ 7-1

7.1 Mitigation Measures ........................................................................................... 7-1

7.2 Monitoring......................................................................................................... 7-10

8 LIST OF PREPARERS .................................................................................................. 8-1

9 REFERENCES............................................................................................................... 9-1

ANNEXES
ANNEX A: NEMC’s Scoping Report Approval
ANNEX B: Fauna Observations In and Near the Project Area
ANNEX C: Relevant Sections of the Scoping Statemwent
ANNEX D: Mgongola Irrigation Scheme Environmental Flow Assessment in
the Wami River

TABLES
Table 1.1: Comparison of Alternatives ................................................................... 1-5
Table 1.2: Mitigation Measures for Operation of Preferred Alternative .................. 1-6
Table 3.1: Pesticides Generally Sold By Agro-Dealers In Morogoro ..................... 3-7
Table 4.1: Canal Network..................................................................................... 4-13
Table 4.2: Flow Measurement Structures ............................................................ 4-15
Table 4.3: Drainage Channels ............................................................................. 4-16
Table 4.4: Proposed Structures ........................................................................... 4-17
Table 4.5: Internal Roads ..................................................................................... 4-18
Table 4.6: Characteristics of AGG Extension ....................................................... 4-26
Table 4.7: Mitigation Measures for Mobilization and Construction Common to
the Proposed Action and All Irrigation Alternatives ............................. 4-30
Table 4.8: Mitigation Measures for Operation ...................................................... 4-31

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 Table 4.9: Environmental Impacts Associated with Mobilization and
Construction ........................................................................................ 4-32
Table 4.10: Quantitative Comparison of the Impacts of Alternatives During
Operation ............................................................................................ 4-32
Table 4.11: Qualitative Comparison of the Impacts of Alternatives ....................... 4-33
Table 5.1: Soils in Mgongola Irrigation Scheme Area ............................................ 5-3
Table 5.2: Minimum Monthly Discharges of Mkindo River (m3/s)........................... 5-6
Table 5.3: Existing Permitted Water Users Upstream and Downstream of the
Confluence of the Wami and Diwale rivers ........................................... 5-8
Table 5.4: Dry Year Recommended Average Discharges for the Wami River
at Mtibwa and Mandera EFA Sites ...................................................... 5-10
Table 5.5: Water Quality Data from EFA Sites ..................................................... 5-11
Table 5.6: Fauna Observed In and Near the Project Area ................................... 5-14
Table 6.1: Potentially Significant Impacts Identified in the Scoping Statement ...... 6-2
Table 6.2: Low-Flow Year Residual Flows and Recommended Average
Discharge (RAD) at the Mtibwa EFA Site (m3/s) ................................. 6-13
Table 7.1: Mobilization and Construction Mitigation Measures for the
Proposed Action and All Irrigation Alternatives ..................................... 7-2
Table 7.2: Operation Mitigation Measures for the Proposed Action and All
Action Alternatives ................................................................................ 7-7
Table B.1: Bird Observations In and Near the Project Area ...................................B-1
Table B.2: Mammal Observations In and Near the Project Area ............................B-2
Table B.3: Reptile Observations In and Near the Project Area ..............................B-3
Table B.4: Amphibian Observations In and Near the Project Area ........................B-3
Table C.1: Consolidated List of Potential Environmental Issues ........................... C-4
Table D.1: Driest Year Recommended Average Discharge (RAD) at Wami
River at the Mtibwa EFA Site ............................................................... D-1
Table D.2: Catchment and Flow Characteristics at Diwale and Mkindo
Gauging Stations.................................................................................. D-2
Table D.3 Low-flow Residual Flows (m3/s) in Relation to the RAD at Mtibwa
EFA Site, End of 2016 Scenario .......................................................... D-6
Table D.4: Low-flow Residual Flows (m3/s) in Relation to the RAD at Mtibwa
EFA Site, 5 to 10 Years in Future Scenario ......................................... D-7
Table D.5: Low-flow Residual Flows (m3/s) in Relation to the RAD at Mtibwa
EFA Site with Sprinkler Irrigation, Current Abstractions Scenario ....... D-8

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FIGURES
Figure 3.1: General Location of Mgongola Irrigation Scheme ................................. 3-3
Figure 3.2: Specific Location of the Mgongola Irrigation Scheme ........................... 3-5
Figure 4.2: Location of Project Manager’s Office and Other Support Facilities ..... 4-11
Figure 4.3: Possible Borrow Pit Locations ............................................................. 4-12
Figure 4.4: General Layout of the Main Canal ...................................................... 4-14
Figure 4.5: Typical Tertiary Canal and Drain Cross-section .................................. 4-16
Figure 5.1: Wami River Basin.................................................................................. 5-1
Figure 5.2: Annual Rainfall in Morogoro Town, 1922-1988 ..................................... 5-4
Figure 5.3: Annual Rainfall in Morogoro Region, 1980-2006 .................................. 5-4
Figure 5.4: Monthly Mean Flow Rate of Mkindo River ............................................ 5-6
Figure 5.5: Mkindo River Daily Flows (2009/2010) ................................................. 5-6
Figure 5.6: Wami River Basin with EFA Sites ....................................................... 5-10
Figure 5.7: Google View of Vegetation in the Project Area ................................... 5-13
Figure 5.8: Land Use in the Project Area .............................................................. 5-17
Figure 6.1: Schematic Location and Relation of Factors for EFA Analysis on
the Wami River at Mtibwa EFA Site .................................................... 6-11
Figure D.1: Schematic of the Diwale/Wami Watershed from the Dakawa Gauge
to the Mtibwa EFA Site......................................................................... D-3
Figure D.2: Recorded Monthly River Flows at Dakawa 1953-1983 ........................ D-5

ENVIRONMENTAL ASSESSMENT
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Acronyms and Abbreviations
22 CFR 216 Title 22 of the U.S. Code of Federal Regulations, Part 216
AGG Agriculture Green Growth, an initiative of SAGCOT
AWD Alternating Wet/Dry, an irrigation regime
CFR Code of Federal Regulations
EA Environmental Assessment
EFA Environmental Flow Assessment
EIA Environmental Impact Assessment
FAO Food and Agriculture Organization of the United Nations
FTF Feed the Future
GoT Government of Tanzania
IEE Initial Environmental Examination
IRRIP Irrigation and Rural Roads Infrastructure Project
IUCN International Union for the Conservation of Nature
iWASH Integrated Water, Sanitation and Hygiene Program, a USAID-funded
project
JICA Japan International Cooperation Agency
LGA Local Government Authority
MAFC Ministry of Agriculture, Food Security and Cooperatives
MZITSU Morogoro Zonal Irrigation and Technical Services Unit
NAFAKA Tanzania Staples Value Chain Activity, a USAID-funded project that is
part of the FTF program
NEMC National Environment Management Council
O&M Operations and Maintenance
PERSUAP Pesticide Evaluation Report and Safe Use Action Plan
PPE Personal Protective Equipment
RAD Recommended Average Discharge
SAGCOT Southern Agricultural Growth Corridor of Tanzania
SEHASP Site Environment, Health and Safety Plan
STDs Sexually Transmitted Diseases
STIs Sexually Transmitted Infections
TANROADS Tanzania National Roads Agency
uPVC Unplasticized Polyvinylchloride (pipe)
USAID United States Agency for International Development

ENVIRONMENTAL ASSESSMENT
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WRBWO Wami-Ruvu Basin Water Office
WSDP Water Sector Development Program
WUA Water Users Association

Units of Measurement
ha hectare
kg kilogram
kg/ha kilogram/hectare
km kilometer
kw kilowatt
l liter
l/s liters/second = 0.001 m3/s
l/s/h liter/second/hectare
m meter
m2 square meter
m3 cubic meter
m3/s cubic meter/second = 1,000 l/s
mm millimeter
mt metric tonne
mt/ha metric tonnes/hectare

ENVIRONMENTAL ASSESSMENT
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1 SUMMARY
This Environmental Assessment (EA) has been prepared by the Engineering
Services for the Tanzania Irrigation and Rural Roads Infrastructure Project (IRRIP1)
for the construction of an irrigation scheme at Mgongola in Hembeti Ward, Mvomero
District, Morogoro Region, Tanzania. Construction of the Mgongola irrigation
scheme is an activity being undertaken as part of the Feed the Future (FTF) program
of the Tanzanian Mission of the United States Agency for International Development
(USAID/Tanzania).

1.1 Purpose and Need

1.1.1 Purpose of Feed the Future
USAID/Tanzania’s FTF documentation states that despite a decade of economic
growth at 6-7%, about one-third of Tanzania’s population continues to live in poverty.
Malnutrition is high, with stunting rates among children under-five at 42% and
maternal anemia at 58%. Agriculture contributes to nearly one-third of gross
domestic product, employs approximately 75% of the population, and has enormous
potential to reduce poverty and improve lives.
FTF Tanzania’s goal is to reduce the poverty rate and increase the agricultural sector
annual growth rate from 3.2 to 6.3 percent by 2015 in the target regions of Zanzibar,
Dodoma, Manyara and Morogoro. This is to be achieved by increasing:
yields of target crops by at least 50 percent (rice from 2 to 3-4 T/ha,
maize from 1.5 to 2.5 T/ha) through dissemination and adoption by
farmers of improved farm technologies and agronomic practices such
as use of improved seeds and fertilizer. Irrigated agriculture will be
promoted to improve productivity and to mitigate the impacts of
climate change. (USAID 2011, pg. 15)
1.1.2 Purpose of IRRIP1
The objective of IRRIP1 is to improve the productivity of the agricultural sector,
particularly for irrigated rice and horticulture, through the rehabilitation of existing
irrigation schemes and the development of new irrigation schemes in the FTF target
region of Morogoro.
1.1.3 Purpose of the Construction of the Mgongola Irrigation Scheme
Construction of the Mgongola irrigation scheme is a project that the GoT and
USAID/Tanzania identified for implementation under FTF. The purpose of the project
is to allow smallholder farmers in Mgongola
to move away from subsistence rain fed agriculture to a more
commercial mode of production through reliable irrigated agriculture
which has proved to be an essential tool for combating food shortages,
and alleviating hunger and poverty in other areas. (MWI 2010)
The area where the irrigation scheme will be constructed is already used by farmers
for paddy rice production, but they are reliant upon unreliable rainfall and the
seasonal wetland conditions for water. Climate change is projected to increase the
unreliability of this source of water by increasing uncertainty of the onset of rainfall
and its regularity (iWASH 2013b).

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 1-1
In line with the goals of FTF – which are aligned with GoT strategies – and the
objective of IRRIP1, the specific objectives of the construction of the Mgongola
irrigation scheme are to:
 Enable water to be supplied on a consistent basis to the existing cultivated
area;
 Enable water to be drained from the area as required for optimal crop
production;
 Provide the structures required to control water flow and to measure water
used, so as to give better conditions for water management, crop growth
and higher yields;
 Reconfigure field layouts to improve on-farm water management;
 Provide reliable access to the fields during rainy season to allow farmers
to deliver inputs and remove harvests, so as to improve crop production
and reduce marketing costs;
 Mitigate the adverse environmental and social impacts caused by the
current farming practices; and
 Establish the physical environment for the Mgongola irrigation scheme to
be constructed and operated in an environmentally sustainable manner.
1.1.4 Need to Which the Project Is Responding
Cultivated rice has a semi-aquatic ancestry and is therefore extremely sensitive to
water shortages, so that when the soil water content drops below saturation, lowland
rice varieties develop symptoms of water stress. As a result, lowland rice (paddy
rice) is grown in level fields which are flooded with water throughout most of the
growing season. The reason for flooding rice fields is that paddy rice varieties
maintain better growth and produce higher yields when grown in flooded soils, than
when grown in dry soils. The water layer also helps to suppress weeds.
A typical water management pattern for paddy rice is as follows (Brouwer et al. 1989,
IRRI 2013)
 The root zone is saturated the month before sowing or transplanting.
 A water layer is established after transplanting. Sometimes a water layer
of 100 mm is established after transplant and maintained throughout the
growing season. In other cases the water layer is reduced to 20 to 50 mm
during the latter part of the vegetative stage and brought back to 100 mm
during the mid-season stage. Generally, water layers greater than 100mm
are detrimental to plant growth.
 Fields are typically drained 10-20 days before harvest, to facilitate
harvesting.
The farmers in Mgongola grow rain-fed lowland rice in bunded fields that are flooded
by rainwater and seasonal wetlands from nearby rivers for at least part of the
cropping season. Rain-fed/wetland lowland rice production is dependent upon the
natural availability of water, making it extremely sensitive to uncertainty in timing,
duration, and intensity of rainfall. The rice fields in Mgongola also suffer from
uncontrolled flooding from the rivers that surround them, causing water levels to
exceed 100 mm. Because of these environmental impacts, rice production from the
rain-fed/wetland fields in Mgongola is low, contributing to poverty in the area.
ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 1-2
Shifting to irrigated lowland rice production via an engineered irrigation and drainage
scheme will stabilize the farmers’ access to water, eliminate flooding and provide
better water management capabilities. This could double rice production with an
associated increase in income (Otenga & Sant'Annab 1999).

1.2 Alternatives
This EA assesses the Proposed Action, four action alternatives and the No Action
alternative. The action alternatives include three irrigation alternatives and one non-
irrigation alternative. The Proposed Action and the three irrigation alternatives will
take 20 months to mobilize, construct and hand over to a Water User Association
(WUA) for operation. Turn over to the WUA will include training, operation and
maintenance manuals, and procedures for water management and distribution. A
quantitative comparison of the alternatives is provided at the end of this section in
Table 1.1. As the table shows, all of the alternatives, including the No Action
Alternative, have negative values for the “% of RAD” impact indicator. A negative
value for this indicator indicates that the Recommended Average Discharge (RAD) at
the Mtibwa Environmental Flow Assessment (EFA) site cannot be met, i.e., the flow
will be less than the flow determined to be necessary to provide for ecological and
small user needs. This is true even for the No Action alternative, because the flow in
the Wami River has been over-allocated. So there is not sufficient flow available for
any new irrigation scheme at Mgongola.
1.2.1 Proposed Action
The Proposed Action is designed to construct a gravity-fed irrigation scheme for
growing paddy rice on the 620 ha (gross1) area in the project area using flood
irrigation. It is an extension of the pilot project (Mkindo I and Mkindo II), which has
successfully demonstrated that smallholder irrigation-based paddy production in
Mgongola is a viable development activity. It will involve:
 Rehabilitation of the existing Mkindo I headworks on the Mkindo River;
 Remodeling of 725 m of the existing Mkindo I main canal;
 Construction of 3.4 km of reinforced concrete lined main canals;
 Construction of 9.6 km of unlined secondary canals;
 Construction of 11.1 km of open channel drains;
 Construction of associated in-field tertiary canals and drains;
 Field levelling;
 Construction of 14.5 km of earthen flood embankment;
 Construction of 16.0 km of gravel-surfaced internal access roads and
feeder roads; and
 Construction and equipping of an office building to be used for
construction supervision and then handed over to the Mgongola Water
Users Association for use in scheme management.
Paddy rice will continue to be the main crop grown; however, other crops may be
cultivated as part of a system of integrated soil, crop and water management;

1 The 620 ha area is the gross area inside the project boundaries and includes the canals and interior
roads. The actual irrigated area will be 589 hectares.

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however, the heavy soils in the project area are far better suited to paddy cultivation
than any other crop.
1.2.2 Piped Main Canal Alternative
The Piped Main Canal alternative differs from the Proposed Action only in that it
constructs a piped main canal, thus reducing evaporation from and unauthorized
tapping of the main canal and increasing conveyance efficiency. All of the other
components of the scheme will be identical to those of the Proposed Action.
1.2.3 Sprinkler Irrigation Alternative
The Sprinkler Irrigation alternative provides the same infrastructure as the Proposed
Action (canals, drainage, flood protection, road improvements, etc.), but adds 17
pumping points at tertiary canals to allow portable diesel pumps to pressurize small
hand-moveable sprinkler irrigation units covering individual basins. This alternative is
designed to secure greater irrigation efficiency for the scheme. A system-wide
pressurized sprinkling alternative was also evaluated, but this modular approach as
an add-on to a flood irrigation system was more cost effective and allows flexibility for
implementation.
This alternative is designed to be operated with portable diesel engines and suction
pumps feeding a portable sprinkling system which would be capable of irrigating a 36
ha area. The pumps and sprinkler systems are not supplied by the project, but rather
farmers who want to use sprinkler irrigation will need to buy this equipment.
Sprinkler irrigation is not suitable for the particular paddy rice varieties preferred by
the local farmers, so this alternative assumes that those farmers who opt to use
sprinklers will switch to dry-foot rice. For this alternative to be successful, it requires
adoption by the farmers of a new crop, a new crop management system and a new
irrigation technology.
1.2.4 SRI Alternative
The System of Rice Intensification (SRI) alternative has the same irrigation
infrastructure as the Proposed Action, however, cultivation practices and water
management will follow SRI prescriptions consisting of:
 Growing seedlings in nurseries.
 Transplanting 8- to 12-day-old seedlings.
 Planting only one seedling per hill in hills spaced widely apart in a grid.
 Controlling weeds with a rotating hand hoe, which also aerates the soil.
 Applying compost to increase the soil’s organic matter content.
 Using Alternating Wet/Dry (AWD) irrigation application.
This alternative requires development and implementation of a concerted, multi-year
extension program operated in conjunction with local government extension agents.
This is required because the SRI prescription significantly varies from the cultivation
system the farmers are presently using as well as from the irrigation practices used in
the neighboring Mkindo irrigation schemes, which the farmers are familiar with.
1.2.5 Improved Intensified Rain-Fed Agriculture Alternative
The Improved Intensified Rain-Fed Agriculture alternative would not build an
irrigation infrastructure in the Mgongola Project area. Instead of providing irrigation,
this alternative would provide a yet to be designed extension program to promote
improved agricultural practices to the farmers in the area. The program would
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 1-4
 incorporate components that have been promoted by NAFAKA, another USAID-FTF
project.
1.2.6 No Action Alternative
The No Action alternative means that USAID would not construct an irrigation
scheme or initiate activities to improve rain-fed agriculture in Mgongola. In this case,
the farmers would continue to use their current rain-fed cultivation practices in the
project area to grow rice.

Table 1.1: Comparison of Alternatives

ALTERNATIVES
Piped
Proposed Main Sprinkler Improved No
Impact Action Canal Irrigationa SRIa Rain-Feda Action

Cost ($1,000,000)b 5.0 5.7 5.4-7.2 5.0 NA 0

Rice Production (mt/ha)
At turnover 3.2 3.2 3.2 3.2 1.6 1.6
With Extension Programc 4.9 4.9 4.9 4.9 3.2
Conveyance Efficiency 88% 92% 88-97% 88% NA NA
Application Efficiency 60% 60% 60-75% 60-80% NA NA
Overall Efficiency 53% 55% 53-73% 53-70% NA NA
Water abstraction for new
589 ha (m3/s) 1.18 1.14 0.86-1.18 0.89-1.18 NA NA

% of RADd -40 to -41 to

-51% -50% -12% -12%
-51% -51%
Notes:
a
Several of the impacts will increase over time, assuming that farmers adopt the improved system
(Sprinkling, SRI, or Improved Rain-Fed Cultivation).
b
Cost is only for construction of the irrigation infrastructure and training in its use. It does not
include the cost for extensions services for rice cultivation.
c Provision of extension services is optional for the Proposed Action, and the Piped Main Canal
alternatives. Extension services are required for implementation of the Sprinkler Irrigation,
SRI and Improved Rain-Fed alternatives.
d
Percent of Recommended Average Discharge at the Mtibwa EFA location given the withdrawal of the
irrigation requirement for the period of greatest impact (2nd half of March). Data from Table 6.2 and its
supporting analyses.

1.3 Major Conclusions

Although the project mobilization and construction activities are extensive, they are
all to the project area, which is already under cultivation, there will be no changes in
land cover. The impacts associated with mobilization and construction are those
common to any construction activity involving earth movement and concrete and can
be mitigated via contract conditions. Implementation of the mitigation will be
monitored by IRRIP1 in its role as the Project Manager during construction.
IRRIP1 conducted an analysis (Annex D) of the impacts of water withdrawals on
downstream users (human and ecological) on the Wami River using the
environmental flow assessment studies and the best information available. That
analysis is summarized in the “Water Quantity Impacts on Downstream Users and
Ecosystems” discussion in Section 6.2.2.2, including Figure 6.1 and Table 6.2. The
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 1-5
analysis indicates that there will be a significant immitigable impact on
downstream users in two periods (2nd periods of March and June) from the
withdrawals associated with any of the irrigation alternatives. This negative
impact is a condition caused by planned over-allocation of the flow to other users
through water abstraction permits. This impact exists regardless of which alternative
is selected; however, the non-irrigation alternatives as well (Improved Intensified
Rain-Fed Agriculture and No Action) will not have an effect on flows. Therefore, the
non-irrigation alternatives will not aggravate that condition.
The EA identified several other direct and indirect environmental impacts that are
expected during project operation. With the application of the specific mitigation
measures, none of these impacts are anticipated to be significant.

1.4 Preferred Alternative

Due to the existence of immitigable significant impacts on downstream water users
associated with all irrigation alternatives, USAID/Tanzania has selected the Improved
Intensified Rain-Fed Agriculture alternative as the preferred alternative instead of the
Proposed Action. Improved Intensified Rain-Fed Agriculture will not have a negative
effect on flows and will not contribute to the over-allocation of the Wami River.
The preferred alternative (Improved Intensified Rain-Fed Agriculture) will not have
mitigation measures during mobilization and construction, as there will be no
mobilization and construction. The mitigation measures for the preferred alternative
during operation are presented in Table 1.2.

Table 1.2: Mitigation Measures for Operation of Preferred Alternative

Impact General Mitigation Measure
Effects of Pesticides and Implementation of the NAFAKA PERSUAP
Fertilizer Use Sensitization of farmers on fertilizer use
Same as for Effects of Pesticides and Fertilizer Use
Water Contamination Periodic water quality monitoring downstream of drainage
discharges
Effects on Aquatic Same as for Effects of Pesticides and Fertilizer Use
Species Water quality monitoring downstream of drainage discharges
Create a livestock corridor providing access to rivers in dry season
Designate grazing and watering areas outside of the project
Land Use Conflicts –
boundaries
Cultivation/Grazing
Establish an NGO composed of farmers and herders to address
cultivation/grazing conflicts

1.5 Areas of Controversy and the Issues to be Resolved

Two impacts during operation warrant special concern and follow-up monitoring:
 Land use conflict between cultivation and grazing; and
 Effects of pesticides and fertilizer use.
Pastoralists from the Kambala village, 7 kilometers south of the project area, bring
their cattle to the banks of the Mgongola, Dizingwa and Mkindo rivers during the dry
season to gain access to water and to graze their cattle on fallow, rain-fed farmland,
including that in the Mgongola project area. This has caused conflicts between
farmers and cattle herders in recent years, even to the point of violence (de Bruin et

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al. 2012). This conflict is likely to increase. Local Government Authorities and the
Morogoro Zonal Irrigation and Technical Services Unit will need to work with the
farmers in the Mgongola project area and the pastoralists from Kambala to develop
acceptable alternatives for securing access to water and feed for the cattle during the
dry season.
The assessment of fertilizer and pesticide use on the local rivers and their
ecosystems at and downstream from the Mgongola project area was based on
professional judgment, as there is no water quality data for the river in the vicinity of
the of the project area that would allow analysis. It would be prudent to collect water
quality data and do an analysis of these impacts during at least one cropping season.
If a problem is identified, then a subsequent routine monitoring program should be
established and on-farm use controls implemented.

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2 INTRODUCTION
This Environmental Assessment (EA) has been prepared by the Engineering
Services for the Tanzania Irrigation and Rural Roads Infrastructure Project (IRRIP1)
for the construction of the irrigation scheme at Mgongola in Hembeti Ward, Mvomero
District, Morogoro Region, Tanzania. Construction of the Mgongola irrigation
scheme is an activity being undertaken as part of the Feed the Future (FTF) program
of the Tanzanian Mission of the United States Agency for International Development
(USAID/Tanzania).

FTF is the United States Government’s global hunger and food security initiative.
The program supports country-driven approaches to address the root causes of
hunger and poverty. It is aimed at forging long-term solutions to chronic food
insecurity and inadequate nutrition. Through this initiative, the United States is
helping countries including Tanzania to transform their own agricultural sectors to
grow enough food to sustainably feed their people.

Tanzania has an ambitious plan to prioritize agriculture for economic growth. The
Government of Tanzania (GoT) has endorsed the development and promotion of the
Southern Agriculture Growth Corridor of Tanzania (SAGCOT) as an inclusive, multi-
stakeholder partnership to rapidly develop the region’s agricultural potential. The
SAGCOT initiative is further linked to the Agricultural Sector Development Program
through Tanzania’s Comprehensive African Agriculture Development Program
investment plan. FTF is fully aligned with GoT’s initiatives and focuses on making
targeted investments across a broad spectrum of agriculture and nutrition
interventions to help ensure long-term sustainability of poverty reduction and nutrition
goals.

USAID/Tanzania identified irrigated rice as the priority value chain for investment in
its FTF program (USAID 2010, pg. 8). Rice was selected as the primary value chain
based on a regional analysis indicating that Tanzania has a comparative advantage
in rice production, although there are opportunities to enhance competitiveness. It is
the second most important food in terms of consumption in the Tanzanian diet, and
has been increasing as a proportion of the Tanzanian diet, and also has potential to
provide for regional market demand. Since nearly one in five farmers are involved in
rice production, advances in this value chain – by improving inputs and techniques,
and irrigation and rural road infrastructure – can support broad-based growth.

FTF interventions cover a broad range of activities centered around (1) developing
the rice sector to spur growth; (2) increasing food security through improved
productivity, processing, transport, and storage in the maize and rice sectors; and (3)
improving the nutritional status of Tanzanians, particularly women and children,
through the development of the horticulture sector.

IRRIP1, managed by CDM Smith, is one of eight projects implementing

USAID/Tanzania’s FTF program. It provides engineering services (planning,
feasibility assessment, detailed design, procurement support, and construction
supervision activities) for rice irrigation schemes in the Morogoro Region.

This EA has been prepared in accordance with USAID’s environmental regulations

as contained in 22 CFR 216. The Initial Environmental Examination (IEE) conducted
for the FTF program gave major irrigation rehabilitation a Positive Determination.
The construction of the Mgongola irrigation scheme falls into this category, and as

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such, an EA is required before project implementation. A Scoping Statement for this
EA was developed and submitted to USAID on 28 March 2014.

In addition to meeting USAID’s environmental requirements, the construction of the

Mgongola irrigation scheme was categorized by Tanzania’s National Environment
Management Council (NEMC) as requiring an Environmental Impact Assessment
(EIA) in accordance with the Environmental Management Act No 20 of 2004 and the
Environmental Assessment and Audit Regulations of 2005. As such, a Scoping
Report was submitted to NEMC on 24 September 2013. NEMC approved the
Scoping Report on 18 October 2013. A copy of the NEMC approval letter is included
as Annex A. The Draft Environmental Impact Statement, which reports on the EIA,
was submitted to NEMC on 14 March 2014.

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3 PURPOSE OF THE PROPOSED ACTION
As required by USAID’s Environmental Procedures in 22 CFR 216.6(c)(2), this
section specifies the underlying purpose and need to which USAID is responding in
proposing the project and its alternatives.
USAID/Tanzania’s FTF documentation states that despite a decade of economic
growth at 6-7%, about one-third of Tanzania’s population continues to live in poverty.
Malnutrition is high, with stunting rates among children under-five at 42% and
maternal anemia at 58%. Agriculture contributes to nearly one-third of gross
domestic product, employs approximately 75% of the population, and has enormous
potential to reduce poverty and improve lives.

3.1 Purpose of Feed the Future

FTF Tanzania’s goal is to reduce the poverty rate and increase the agricultural sector
annual growth rate from 3.2 to 6.3 percent by 2015 in the target regions of Zanzibar,
Dodoma, Manyara and Morogoro. This is to be achieved by increasing:
yields of target crops by at least 50 percent (rice from 2 to 3-4 tons/ha,
maize from 1.5 to 2.5 tons/ha) through dissemination and adoption by
farmers of improved farm technologies and agronomic practices such
as use of improved seeds and fertilizer. Irrigated agriculture will be
promoted to improve productivity and to mitigate the impacts of
climate change. (USAID 2010, pg. 15)

3.2 Purpose of IRRIP1

The objective of IRRIP1 is to improve the productivity of the agricultural sector,
particularly for irrigated rice and horticulture, through the rehabilitation of existing
irrigation schemes and the development of new irrigation schemes in the FTF target
region of Morogoro.

3.3 Purpose of the Construction of the Mgongola Irrigation Scheme

Construction of the Mgongola irrigation scheme is a project that the GoT and
USAID/Tanzania identified for implementation under FTF. The purpose of the project
is to allow smallholder farmers in Mgongola
to move away from subsistence rain fed agriculture to a more
commercial mode of production through reliable irrigated agriculture
which has proved to be an essential tool for combating food shortages,
and alleviating hunger and poverty in other areas. (MWI 2010)
In line with the goals of FTF – which are aligned with GoT strategies – and the
objective of IRRIP1, the specific objectives of the construction of the Mgongola
irrigation scheme are to:
 Enable water to be supplied on a consistent basis to the existing cultivated
area;
 Enable water to be drained from the area as required for optimal crop
production;
 Provide the structures required to control water flow and to measure water
used, so as to give better conditions for water management, crop growth
and higher yields;

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  Reconfigure field layouts to improve on-farm water management;
 Provide reliable access to the fields during rainy season to allow farmers
to deliver inputs and remove harvests, so as to improve crop production
and reduce marketing costs;
 Mitigate the adverse environmental and social impacts caused by the
current farming practices; and
 Establish the physical environment for the Mgongola irrigation scheme to
be constructed and operated in an environmentally sustainable manner.

3.4 Need to Which the Project Is Responding

Cultivated rice has a semi-aquatic ancestry and is therefore extremely sensitive to
water shortages, so that when the soil water content drops below saturation, lowland
rice varieties develop symptoms of water stress. As a result, lowland rice (paddy
rice) is grown in level fields which are flooded with water throughout most of the
growing season. The reason for flooding rice fields is that paddy rice varieties
maintain better growth and produce higher yields when grown in flooded soils, than
when grown in dry soils. The water layer also helps to suppress weeds.
A typical water management pattern for paddy rice is as follows (Brouwer et al. 1989,
IRRI 2013)
 The root zone is saturated the month before sowing or transplanting.
 A water layer is established after transplanting. Sometimes a water layer
of 100 mm is established after transplant and maintained throughout the
growing season. In other cases the water layer is reduced to 20 to 50 mm
during the latter part of the vegetative stage and brought back to 100 mm
during the mid-season stage. Generally, water layers greater than 100mm
are detrimental to plant growth.
 Fields are typically drained 10-20 days before harvest, to facilitate
harvesting.
The farmers in Mgongola grow rain-fed lowland rice in bunded fields that are flooded
by rainwater and seasonal wetlands from nearby rivers for at least part of the
cropping season. Rain-fed/wetland lowland rice production is dependent upon the
natural availability of water, making it extremely sensitive to uncertainty in timing,
duration, and intensity of rainfall. The rice fields in Mgongola also suffer from
uncontrolled flooding from the rivers that surround them, causing water levels to
exceed 100 mm. Because of these environmental impacts, rice production from the
rain-fed/wetland fields in Mgongola is low, contributing to poverty in the area.
Shifting to irrigated lowland rice production via an engineered irrigation and drainage
scheme will stabilize the farmers’ access to water, eliminate flooding and provide
better water management capabilities. This could double rice production with an
associated increase in income (Otenga & Sant'Annab 1999).
3.4.1 Location
The proposed Mgongola irrigation scheme will be located in Hembeti Ward, Mvomero
District, Morogoro Region. It is part of the extensive Mkata Flood Plain which is
drained to the east by the Wami River and its tributaries. The project area lies north
of Morogoro town and is accessible, from Morogoro town, by an all-weather road (B-
127) to Mvomero (80 km) and during the dry season a short-cut road via Dakawa (65

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km) (Figure 3.1). The specific project site is situated between the Mkindo-Dizingwi
River to the north and the Mgongola River to the south (Figure 3.2). Two villages,
Mkindo Village and Dihombo Village are near the eastern boundary of the project
site. Elevation ranges from 345 m to 365 m above sea level. The site is located
between latitudes 37°32’E and 37°36’E and longitudes 6°16’S and 6°18’S.

Figure 3.1: General Location of Mgongola Irrigation Scheme

3.4.2 Background
Irrigated paddy rice was introduced to the farmers in the Mgongola area in the mid-
1980s via a development project funded by the Netherlands Government. The
project was designed as a pilot program to determine the viability of smallholder
irrigation-based paddy production in the area. The project constructed a diversion
intake structure on the Mkindo River and a 2.5-km main canal with a siphon crossing
the Dizingwa River. It also supported on-farm works, which included land levelling
and formation of paddy ridges on 40 ha (17 ha serving 42 families north of the
Dizingwa River and 23 ha serving 50 families south of it). The irrigated area north of
the river is called Mkindo I and the irrigated area south of the river is called Mkindo II
(Figure 3.2).
Since its construction, the area under irrigated cultivation has been expanded to 110
ha. At some point in the past 25 years the siphon crossing the Dizingwa River has
failed, and Mkindo II now takes water directly from the Dizingwa River. In 2012, the
headworks and main canal underwent rehabilitation under the supervision of the
Morogoro Zonal Irrigation and Technical Services Unit (MZITSU). MZITSU fully
rehabilitated the gates at the headwork and expanded and concrete-lined the main
canal from the intake to the end of Mkindo I (1.2 km).
The Mkindo irrigators are organized into the Mkindo Farmers Agricultural and
Marketing Cooperative Society. This cooperative society was established in 1984 to
manage the Mkindo irrigation schemes and to look for markets for its products. It
was registered as a cooperative with the MAFC in 1997. In 1997 it had 97 members
and the area under irrigation was 60 ha, instead of the 110 ha under irrigation today.
The cooperative is managed by a committee elected by fellow members every three

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years. The committee makes water and cropping scheduling decisions for the
scheme.
The Mkindo irrigation schemes were designed as pilot projects to demonstrate that
small-holder irrigation schemes were a viable development opportunity in the
Mgongola area. The schemes have been successful, allowing the farmers in the
schemes to produce more rice than the farmers around them that rely upon rain-fed
production.
In the late 1990s, the then Ministry of Agriculture and Cooperatives (now the Ministry
of Agriculture, Food Security and Cooperatives [MAFC]) with support from the Japan
International Cooperation Agency (JICA) prepared a master plan for smallholder
irrigation projects in the central Wami River Basin. Mgongola was one of the
potential projects for which a feasibility study was prepared (JICA 1998). That study
proposed a new irrigation scheme east of Mkindo I and II in the area between the
Mkindo-Dizingwi River and the Mgongola River. It is this project which the GoT and
USAID/Tanzania identified for implementation under FTF, and which is the subject of
this Environmental Assessment.

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Figure 3.2: Specific Location of the Mgongola Irrigation Scheme

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3.4.3 Existing Agricultural Practices in the Project Area
The project area is currently used for rain-fed paddy rice cultivation by as many as
725 farmers. The farmers in this area generally use Supa India seed, a common
local aromatic variety in Tanzania, although other local seed (Supa Mbeya, Supa
Shinyanga, and Domo la fisi) are also used to a lesser extent. A limited number of
farmers use the improved seed, Saro 5 (TXD 306). Sowing of rice seed is done via
broadcast seeding from December to January, depending on the availability of rain,
as germination is dependent upon rainfall. Harvesting is done in May and June.
Land preparation, cultivation and harvesting is generally done by hand, although
some land preparation may be done by hired tractors. The farmers generally do not
use fertilizers or pesticides, although herbicides may be used for weed control and
manual bird scaring is done during the ripening stage of the paddy. (JICA 1998, de
Bruin 2012)
Ponding, a desired condition in the fields after germination, is dependent upon
seasonal flooding, which varies from year to year. Rain-fed rice farmers create
bunds in their fields before the rains to trap flood water as the flooding recedes (de
Bruin et al. 2012). Flooding can also be a problem, as farmers have no way of
draining water when it is not desirable. Keraita et al. (2012) reports seeing flood
water 0.5-m deep in rain-fed rice fields in the Hembeti area (very near to the
Mgongola project area) during harvest period, when paddy fields should be dry.
In 2013 the USAID-funded NAFAKA project, part of the FTF program, commissioned
a consultancy on the status of agricultural practices in the Mvomero District (IFDC
2013). The consultancy found that:
 Few farmers in the district (less than 5%) use fertilizer for rain-fed paddy
rice, due to limited availability at the village level, poor purchasing power,
lack of credit, poor roads, and lack of understanding about fertilizer use.
 Rain-fed paddy rice farmers tend to have weed problems (particularly
grasses) and use herbicides to address those problems (see Table 3.1),
but generally were not successful at controlling the weeds.
 Generally rain-fed paddy rice farmers do not use fungicides or
insecticides, even though paddy rice in the district is subject to several
diseases (bacterial blight, leaf blast, neck blast, sheath blight, brown spot
false smut, and grain discoloration) and insect pests (brown plant hopper,
stem borer, green hoppers, leaf folder, cut worms, termites, thrips, mealy
bug and beetles). Most agro-dealers stock a limited number of fungicides
and insecticides useful in paddy rice production (see Table 3.1).
 Paddy growers in rain-fed areas are not properly levelling their lands,
which leads to uneven moisture distribution leading to gaps and dwarf
growth.
 Seed rate used by paddy growers is 120 to 150 kg/h of seed, which are 6
times what would be required using improved sowing practices.
 Farmers prefer to grow traditional rice varieties, which give poor yields
than improved varieties but have an aromatic nature preferred by the
consumers. Seed sowing is collected each year during harvest.
 Growing improved varieties requires purchasing certified quality seeds,
which are generally unavailable. Even when improved varieties are used,
the farmers still collect seed for sowing during the harvest, rather than
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 3-6
 purchasing new seed each year. This practice reduces yields over time as
the hybrids lose some of their characteristics with each succeeding
generation.
 Almost all of the labor is done by hand.
 Poor harvesting practices have led to decreased quality of rice and a
resulting lower value for the rice.
Although these practices are general to the Mvomero District, they are most likely
common to the rain-fed farmers in the project area.

Table 3.1: Pesticides Generally Sold By Agro-Dealers In Morogoro

Fungicides Herbicides Insecticides
Copper oxychloride (CoC) 2,4-D Aluminum phosphide
Hexaconazole Atrazine Profenofos
Tebuconazole + Triadimenol Diuron Chlorpyrifos
Triadimenol Glyphosate Cypermethrin
Paraquat Dimethoate
Pendimethalin Endosulfan
Fenitrothion
Malathion
Sources: ACDI/VOCA 2012, IFDC 2013

The PERSUAP for NAFAKA found that “Most small- and medium-scale farmers
rarely use PPE other than boots, long pants, a shirt and a hat” (ACDI/VOCA 2012, pg.
17). It is most likely that this is the situation for the farmers in the project area.

There is limited information on rice production in the project area. An AgWater

Solutions Project study (Keraita et al. 2012) conducted in the Mkindo area in 2009
and 2010 and based on interviews with farmers in the area found that average yield
in the Mkindo schemes during the rainy season was 6.0 mt/ha, whereas average
yield for rain-fed Mkindo plots was 3.0 mt/ha. The JICA study (JICA 1998) found rice
production levels to be much lower (3.8 mt/ha for irrigated plots and 1.6 mt/ha for
rain-fed). Both studies, however, found that irrigated paddy rice in the area produced
twice the yield as rain-fed paddy rice.

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4 ALTERNATIVES
As required in 22 CFR 216.6(c)(3), this section presents the Proposed Action and
reasonable alternatives that meet the purpose and need of the Proposed Action, as
well as the no action alternative. This section also includes a brief description of the
reasons for eliminating those alternatives which were not included in the detailed
analysis. For the Proposed Action and the action alternatives, this section presents
general mitigation measures. (Specific mitigation measures are presented in
Section 7.1 of this EA.) The section concludes with a comparative analysis of the
environmental impacts of the Proposed Action and each alternative.

4.1 The Proposed Action

The Proposed Action is to construct a gravity-fed irrigation scheme for growing paddy
rice on the 620 ha (gross2) area in the project area using flood irrigation. It is an
extension of the pilot project (Mkindo I and Mkindo II), which has successfully
demonstrated that smallholder irrigation-based paddy production in Mgongola is a
viable development activity.
As mentioned in Section 3.4.2, MAFC, with support from JICA, prepared a feasibility
study in 1998 for a new irrigation scheme east of Mkindo I and II in the area of the
proposed project. IRRIP1 evaluated this study to determine its applicability to the
present situation and assess how its conclusions could be applied and/or updated
(CDM 2013b). This evaluation found that in general the feasibility study provided a
sound basis for designing an irrigation scheme for Mgongola. In addition to the
evaluation, IRRIP1 held discussions with project area farmers, the GoT and USAID.
Based on the results of the evaluation and the stakeholder discussions, IRRIP1
prepared a Design Report (CDM Smith, 2013a) proposing recommendations for
construction of the Mgongola irrigation scheme. Those recommendations define the
Proposed Action.
A general layout of the Proposed Action is shown in Figure 4.1. The Proposed
Action will involve the following:
 Rehabilitation of the existing Mkindo I headworks (diversion from the
Mkindo River);
 Remodeling of 725 m of the existing Mkindo I main canal;
 Construction of 3.4 km of reinforced concrete lined main canals;
 Construction of 9.6 km of unlined secondary canals;
 Construction of 11.1 km of open channel drains;
 Construction of associated in-field tertiary canals and drains;
 Field levelling;

2 The 620 ha area is the gross area inside the project boundaries and includes the canals and interior
roads. The actual irrigated area will be 589 hectares.

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Figure 4.1: General Layout of the Proposed Action

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  Construction of 14.5 km of earthen flood embankment surrounding the
irrigable area and main canal alignment;
 Construction of 16.0 km of gravel-surfaced internal access roads and
feeder roads; and
 Construction and equipping of an office building to be used for
construction supervision and then handed over to the Water Users
Association for use in scheme management.
The specifications for these components are elaborated in the following subsections.
Mobilization and construction of the Proposed Action is anticipated to occur over 20
months (assuming all construction contracts run concurrently). Construction will be
scheduled to the extent possible around the existing agricultural activities, as well as
the rainy seasons. The contractor(s) will be required to plan their works in such a
way that the 725 m of the existing Mkindo I main canal can operate in its original
condition or in its remodeled state throughout each irrigation season. As such, no
temporary canal diversions are foreseen. However, should temporary canal
diversions be required, they will be programmed by the contractor in consultation with
the Project Manager in such a way as to minimize the interruption of flows to the
downstream irrigators and under no account will the contractor be allowed to
jeopardize the irrigated crops reliant upon the water.
Temporary diversion of the Dizingwi River will be required where the Main Canal and
access road cross over the river (Figure 4.1). It is envisaged that this will be easiest
during the dry season when flows are generally at their lowest.
The Proposed Action would have an estimated construction cost of $ 5,015,000. It
would have an estimated irrigation water conveyance efficiency of 88% (weighted
average by length: 90% for the Main Canal and 85% for the Secondary and Tertiary
Canals3), with application efficiencies of 60%. This gives an overall expected
irrigation efficiency of 53%.
4.1.1 General Construction Activities
The following activities are generally common to all construction activities:
 Set up and operation of offices, housing, workshops, equipment
maintenance and materials storage facilities etc. These facilities will
remain after construction and be turned over to Water Users Association
for use in scheme management;
 Establishment of safe access to different parts of the site;
 Location and preparation of borrow pits for embankment fill and road
surfacing materials; and
 Import of construction materials, such as sand, aggregate, cement,
reinforcing steel and gravel and onsite secure storage.
Land is available for the construction of the contractor’s site office, camp, workshops
and materials storage free of cost for the duration of the contract and defects liability

3 The relatively high conveyance efficiencies for the Secondary and Tertiary Canals are due to the high
clay component of the soil through which they run.

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period. The land is located in between the main canal and secondary canal 1, near
to where secondary canal 1 begins (Figure 4.2).

Figure 4.2: Location of Project Manager’s Office and Other Support

Facilities

4.1.1.1 Sources of Aggregates, Sand, Gravel and Fill Material

Aggregates, sand and gravel for rehabilitation works will be obtained and transported
to the site by trucks from the existing source in Lugoba, approximately 200 km away
from the site and north of Dumila. The estimated amount of aggregates required for
the works is about 1,780 m3. It is expected that the volumes required for this work do
not warrant opening a new borrow pit/quarry and crusher site.
The estimated quantity of gravel is about 17,850 m3 to cover 16 km of farm roads.
Gravel is abundant in the project area, and will be secured at the one or more of the
following existing borrow pits:
 Dumila borrow pit (~31 km)
 Mwinyi borrow pit (near Dakawa ~21 km)
 Dizungu borrow pit (near Mkindo ~5 km)
 Veterinary borrow pit (~16 km)
 Konakali borrow pit (~16 km)

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 Figure 4.3: Possible Borrow Pit Locations

To secure sand and gravel a few off-site activities will be required such as storage for
fuel and lubricants to run the equipment involved in abstraction, handling and
haulage of gravel for grading of service roads.
The drains are expected to be a key source of fill material for building canal
embankments, flood bunds, and farm roads. It is expected that all excavation from
drains will be required for fill where suitable. Where more fill is still required, it will
need to be sourced from borrow trenches or pits alongside the flood embankments,
outside of the scheme.
4.1.1.2 Water for Works
Water will be required for the works (e.g. for compaction and concrete batching). It is
anticipated that, since the project will benefit Mkindo I and II and they will be part of
the project management structure (see Section 4.1.6), water for works will be drawn
from the nearby Mkindo River under the existing Mkindo I and II water right. It is
estimated that 75 m3/day of water will be required for construction works, 0.1% of the
daily water right for Mkindo I and II. In some situations, the source of water for offsite
work locations (borrow areas for instance) may require the installation of intakes
close by. In all cases, the contractor(s) will be required to secure necessary permits
for water use during construction.
4.1.2 Irrigation and Drainage Components
4.1.2.1 Headworks
Irrigation water for the Proposed Action will be diverted from the Mkindo River at the
headworks for the Mkindo I irrigation scheme. The headworks are just upstream of a
natural fall which is located approximately 2 km upstream from the trunk road B127
(see Figure 4.1) There is an existing concrete intake equipped with two slide gates

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-12
and two spillways cum sand-flushing gates. Immediately after the intake gates, a
side overflow spillway has been provided to drain excess water to the Mkindo River.
The headworks is of sufficient size to accommodate the proposed irrigation scheme
as well as Mkindo I and II. As noted in Section 3.4.2, the headworks underwent
rehabilitation under the supervision of MZITSU in 2012, however, an inspection of the
gates shows them to be badly corroded and the seals are leaking. The Proposed
Action will rehabilitate the headworks to correct these problems.
4.1.2.2 Main Canal
The main canal will flow 4.0 km from the headworks to the secondary canal 3,
providing water to Mkindo I and II and secondary canals 1 and 2 on its way (Table
4.1 and Figure 4.4). It will be designed for 24-hour continuous supply when irrigation
is required. It will have a concrete lining, in accordance with Government of
Tanzania (GoT) requirements.

Table 4.1: Canal Network

Maximum Area Irrigated

Canal Capacity (m3/s) Length (m) (ha)
Main Canal 1.40 4,037 699a
Mkindo Canalb 0.22 3,024 110
Secondary Canal 1 0.36 3,088 179
Secondary Canal 2 0.55 3,193 277
Secondary Canal 3 0.27 3,297 133
Notes:
a
The 110 ha existing irrigation scheme plus 589 ha (net) of new irrigation.
b
Existing canal serving Mkindo I and II. Not part of the Proposed Action,
but will be served by the Main Canal.

Lining of the main canal at Mgongola has been proposed. It must be noted, as
discussed in CDM Smith 2012a, that lining the canal for water conservation reasons
(seepage-reduction) is not justified. However, the Mgongola project is following a
participatory approach and canal lining has been identified as a priority requirement
by:
 MAFC;
 MZITSU; and
 Mkindo Irrigators’ Organization.
These GoT organizations argued that the lining of main canals is a Tanzanian high-
level policy. When MZITSU rehabilitated the main canal for Mkindo in 2012 using its
own budget, it lined the canal with concrete and stone masonry.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-13
 Figure 4.4: General Layout of the Main Canal

The first 725 m of the main canal will be the first 725 m of the existing Mkindo I main
canal. MZITSU expanded the capacity and lined this section of the main canal in
2012 in preparation for development of the Mgongola irrigation scheme. This stretch
of the main canal is in good condition, although there are some minor cracks and
places which the banks to be raised and storm water cross structures need to be
provided. The Proposed Action will repair the cracks, raise the banks where
necessary, and provide necessary storm water cross structures. This stretch of the
canal varies in cross-sectional shape between trapezoidal and rectangular depending
on the surrounding ground/rock type and topography.
At 725 m, the Proposed Action will construct a division structure with control gates to
divert water into the main canal for the Mgongola irrigation system and the main
canal for Mkindo I and II. Other than providing for this division of water into the
existing Mkindo I and II main canal and a flow measuring structure shortly
ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-14
downstream from the division, the Proposed Action will not include any
improvements for the rest of the Mkindo I and II irrigation schemes.
From the division at 725 m, the Mgongola main canal will run in a generally
southeastern direction, south of the Mkindo Village. Three foot bridges and one road
bridge will be constructed over the canal south of the village to provide access to
land south of the canal. The canal will cross trunk road B127 through an existing 1.2-
m diameter culvert (built in advance by TANROADS during their upgrading of the
B127 in 2012), and then it will cross the Dizingwi River through an inverted siphon.
After crossing the river, the main canal will flow an additional 600 meters to
secondary canal 1. From secondary canal 1 it will flow generally south for another
1.5 km where the secondary canal 2 head regulator marks the end of the main canal
and the beginning of secondary canal 3.
The main canal will have a trapezoidal cross-section from the division at 725 m to
secondary canal 3. It will have flow measurement structures as shown in Table 4.2
to allow flow to the three secondary canals to be closely managed.

Table 4.2: Flow Measurement Structures

Chainage
Canal (m) Type Comments
Downstream of division
Mkindo Main Canal 10 Broad Crested Weir
structure
Full Width Sharp Drop structure downstream of
Mgongola Main Canal 755
Crested Weir division structure
Downstream of secondary
Mgongola Main Canal 2,563 Broad Crested Weir
canal 1 head regulator
Secondary Canal 3 100 Broad Crested Weir Beginning of secondary canal 3

4.1.2.3 Secondary Canals

The scheme will have three secondary canals that deliver water from the main canal
to the tertiary canals (Figure 4.1 and Table 4.1). They will be designed for 24-hour
irrigation supply when irrigation is required. The secondary canals will have
trapezoidal cross-sections and will be unlined, except for the first 100 meters of
secondary canal 3, which will be lined to provide a smooth, weed-free channel
upstream of the measuring weir (Table 4.2).
Each secondary canal will have a gate structure at the head of the canal to control
flow into the canal. Secondary canal no. 2 has a gated turnout structure as an end
structure, which flows into a drain as required. Secondary canals 1 and 3 each end
with a turnout structure flowing into the final field. Where secondary canal 2 crosses
the link road there will be a combined check/culvert/drop/tertiary canal head regulator
structure.
4.1.2.4 Drains
Secondary drains, which collect excess water directly from fields or from tertiary
drains, will be constructed inside of the scheme. Secondary drain 1 will be located
between secondary canals 1 and 2, and secondary drain 2 will be between
secondary canals 2 and 3 (Figure 4.1 and Table 4.3). These drains join and
ultimately flow into the Mgongola River. These drains will be open channel and
unlined.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-15
In addition to the two drains inside the scheme, drain 3 (Figure 4.1 and Table 4.3)
will be constructed along the right hand side, in the direction of flow, of the main
canal. Drain 3 will be open channel and unlined and will serve as a cut-off drain to
take drainage water from the area to the west of the scheme southwards to the
Mgongola River.

Table 4.3: Drainage Channels

Maximum Capacity Length

Drain (m3/s) (m)
Secondary Drain 1 3.28 3,968
Secondary Drain 2 1.79 3,903
Drain 3 2.00 3,225

4.1.2.5 Tertiary Canals, Drains and Land Levelling

Tertiary canals will offtake from the secondary canals and terminate at the secondary
drains (shown as Field Canals in Figure 4.1). Each tertiary canal will serve a tertiary
area of no more than 13, 1 ha plots. At the bottom of each tertiary area will be a
tertiary drain, running alongside and parallel to the tertiary canal serving the adjacent
area (Figure 4.5). The tertiary drains will be used by the farmers to remove water
from the plots and send it to the secondary drains when standing water is not desired
(e.g., for field preparation and harvesting). All tertiary canals and drains will be
unlined and have been designed to minimize earthworks costs by balancing
excavation and fill – i.e., excavated material from the tertiary drain will be used to
construct the tertiary canal embankments (Figure 4.5).

Figure 4.5: Typical Tertiary Canal and Drain Cross-section

The tertiary canals and drains form part of the farmer contribution to the project but
preliminary design assistance will be provided under the Proposed Action. However,
the head regulator for each tertiary canal will be located in the secondary canal and
provided by the Proposed Action.
Following construction of the tertiary canals, the farmer contribution will also include
land levelling, bunds and any additional field channels required. Due to the small
size of the plots (approximately 1 ha), farmers will be able to level their fields
manually using hand hoes. Land levelling must be carried out for several years
following construction and then again periodically in the future. For this reason it is
appropriate that it should be part of the farmer responsibility from the beginning.
However, it is recognized that considerable technical support will need to be provided
to the farmers during this process.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-16
 4.1.2.6 Structures
A summary of structures to be constructed for MIS is shown below in Table 4.4.

Table 4.4: Proposed Structures

Number
Structure Gated or Ungated Discharge Measurement
Required
Superpassage 5 Ungated No
Division Structure 1 Ungated No
RCC Check-Drop
20 Gated No
(for canals)
Sharp-crested weir combined
RCC Drop (for canals) 4 Ungated at MC chainage 755 m for flow
measurement. Otherwise, No.
Footbridge 3 Ungated No
Road Bridge 1 Ungated No
Siphon/Box Culvert 1 Ungated No
SC Head Regulator 2 Gated No
Broad Crested Weir 3 Ungated Yes
Check Structure 1 Gated No
Outlet from SC 51 Gated No
Combined Drop, Ungated (except for
1 No
Culvert, Check outlets to tertiary canals)
Road Culvert (double) 3 Ungated No
Masonry Drop
14 Ungated No
(for drains)
Abbreviations:
RCC Reinforced Cement Concrete
SC Secondary Canal

4.1.3 Flood Protection

The proposed Mgongola irrigation scheme will be protected from high flood water
levels by 14.5 kilometers of flood bunds completely surrounding the scheme and
protecting a portion of the main canal before reaching the scheme. The flood bund
surrounding the scheme will be at least 60 m from the river, as required by
Tanzanian law. This will ensure that it is at a high enough elevation to resist flooding
and will allow an area for borrow outside of the scheme, as well as passage of flood
waters as flooding recedes. The heights of the bunds will be 1.3 m on the Mkindo
River side of the scheme and 1.5 m on the Mgongola River side of the scheme.
4.1.4 Farm Roads
The Proposed Action will construct 15.4 km of internal, gravel surfaced roads for
inspection, operation and maintenance of irrigation, drainage and flood protection
infrastructure as well as for transportation of agricultural inputs and products (Table
4.5). The roads will run along the newly constructed portions of the main canal and
along each secondary canal. In addition, one link road will be built between the
secondary canals and secondary drains.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-17
 Table 4.5: Internal Roads

Length Width Wearing Surface

Road Description
(km) (m) Material Thickness
Main canal access road (bank top) 3.3 6.0 Gravel 0.2 m
Secondary canal access roads 9.6 4.5 Gravel 0.2 m
Link road between secondary canals and drains 2.5 4.5 Gravel 0.2 m

The newly constructed portions of the main canal will have a gravel road on the left
hand side, in the direction of flow, for its entire length. The road will be along the top
of the embankment, will have a width of 6 m and will have a gravel wearing course
with a thickness of 0.2 m. The road will cross the Dizingwi River with a double-cell
box culvert immediately alongside the siphon structure through which the main canal
will flow. The road will connect to regional road B127 (Magole – Turiani Road).
Gravel roads will also be constructed along the secondary canals on both sides,
unless there is a flood bund on one side in which case the road will only be on the
side without a flood bund. These roads will have a width of 4.5 m and a gravel
wearing course with a thickness of 0.2 m. To reduce earthworks and improve access
to fields, the access roads running along the secondary canals are located 0.5 m
above existing ground level, adjacent to the canal embankment, rather than along the
top of the embankments.
The road labeled as “Contractor’s Access Road” in Figure 4.1 is an existing dirt road
that can be used during construction. No improvements are planned for this road.
4.1.5 Demobilization
At the conclusion of construction of the irrigation works, all construction equipment
such as bulldozers, concrete mixers, rollers and the like will be shifted to another site
or to storage places under the control of the contractor. Along with this, rehabilitation
of any damaged areas will be carried out before commissioning the project, in line
with the construction contract documents.
4.1.6 Operation, Maintenance and Management
Once the scheme is constructed it will be turned over to a Water Users Association
(WUA) for operation and maintenance. The plan is for the WUA to include the
current farmers in the Mgongola project area4 as well as those farming in Mkindo I
and Mkindo II, so that the entire irrigated area can be managed by one WUA. The
Mkindo I and Mkindo II farmers currently have their own irrigation organization, but
they are willing to disband that organization and join the new WUA.
MZITSU is coordinating the setting-up and training of the combined WUA. To that
end, they have worked with the farmers to organize an Interim Committee to
establish the WUA. With support from MZITSU, the Mvomero Local Government
Authority (LGA), and NAFAKA, the committee has:
 Established a bank account;

4 At least 725 farmers currently grow rain-fed paddy rice in the project area. Each of them will receive a
plot in the irrigation scheme, so that no current users are displaced. Plots will be allocated to each
farmer proportional in size and at the same location as the area they are currently farming in the
project area.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-18
  Collected Tanzanian 3,730,000shillings in membership fees from
participating farmers (TSH 5,000 each from 746 farmers);
 Signed a Memorandum for the formation of the WUA; and
 Drafted and approved the Constitution of the WUA.
The Interim Committee is currently working with MZITSU, the LGA, and NAFAKA to:
 Secure a consolidated land tenure certificate
 Develop a training program;
 Establish financial management procedures, including collection of water
fees and other dues;
 Establish water management practices and cropping patterns for the
scheme; and
 Develop support for post-harvest processing and marketing.
The Proposed Action will prepare a Management, Operations and Maintenance
Manual for the WUA, which will comply with the National Irrigation Act (2013) as
approved by Parliament in its August-September 2013 session and include an
Environmental Management Plan to define the on-going requirements for operation
of the scheme in accordance with Integrated Water Resource Management
principles, health and safety and environmental requirements.
Among other operational issues and maintenance the manual will cover:
 Distribution of water throughout the project area;
 Monitoring of irrigation water flows and quality and of the quality of the
drainage water leaving the irrigated area; and
 Operation and maintenance of irrigation and drainage infrastructure.
The Proposed Action does not include a cultivation improvement program. Such a
program is beyond the current scope of IRRIP1. NAFAKA, another USAID-FTF
project, however, has conducted improved cultivation activities with Mkindo irrigation
scheme farmers and would provide USAID with a vehicle for pursuing improved
cultivation activities in the Mgongola irrigation scheme as a partner activity. Such
activities would improve the crop yield associated with irrigation.
4.1.7 Cropping
IRRIP1 reviewed a number of alternative crops for use at Mgongola. This review, in
conjunction with the findings from the soil survey report (JICA 1998), concluded that
the heavy soils in the project area are far better suited to paddy cultivation than any
other crop. However, NAFAKA has introduced demonstration plots within the Mkindo
I and II irrigation scheme to investigate alternative crops such as maize, sorghum,
and sunflowers.
NAFAKA is working at the newly formed WUA to develop improved cropping and on-
farm water management practices for paddy rice production. IRRIP1 has worked
with NAFAKA at the field level in Mkindo I and II to optimize the size of irrigated plots
and layout of field canals and drains.
It is anticipated that, as the agricultural demonstrations and developments advance,
a number of different cropping scenarios, combining rice with other crops in rotation
throughout the year, may be tested. The layout of the irrigation infrastructure for the

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-19
Proposed Action is flexible enough to allow a variety of other crops to be grown
without any changes to the system other than revised irrigation scheduling
associated with the different crop type(s).
4.1.8 Irrigation Water Requirements and Water Rights
The proposed cropping pattern for the Mgongola irrigation scheme is single-cropping
of paddy rice during the rainy season, February to June, following land preparation in
January. Mkindo I and II would continue to operate under its existing cropping
pattern: double cropping of paddy under fully irrigated conditions with the first crop
grown during the rainy season from January to June, and the second crop grown
from July to December.
IRRIP1 estimated the irrigation water requirement for the proposed cropping patterns
using daily rainfall data and climatological data. The estimates were carried out on a
10-day basis using CROPWAT 4.05 in accordance with the following procedures:
 Calculate potential evapotranspiration from climate data;
 Estimate consumptive use of water by multiplying potential
evapotranspiration by crop coefficient, including percolation rate in case of
paddy rice;
 Estimate effective rainfall from daily rainfall;
 Calculate net irrigation water requirement deducting the effective rainfall
from the estimated consumptive use of water plus percolation; and
 Calculate irrigation water requirement taking irrigation efficiency into
account.
Following the above procedures, the peak irrigation water requirement at the head of
the system was calculated and adopted at 2.0 l/s/ha. The outcomes of these
calculations are dependent on a large number of highly variable inputs. The
MZITSU, from their local experience working with irrigation schemes, have
developed a policy of design water requirement of 1.5 to 2.0 l/s/ha, so the 2.0 l/s/ha
value appears to be reasonable.
The Mgongola irrigation scheme will develop 589 ha (net) of irrigated paddy.
Considering the additional existing Mkindo I and Mkindo II developments with a
combined irrigated area of approximately 110 ha, the total area to be supplied at the
headworks is 699 ha. This corresponds to a flow of approximately 1.4 m3/s at the
headworks, to supply the entire irrigated area during the rainy season and 0.2 m3/s at
the headworks, to supply Mkindo I and Mkindo II during the dry season.
The Mkindo irrigation organization has a water right to abstract 0.624 m3/s for 24
hours per day with no restrictions on abstractions during the dry-season flows. Once
the new WUA is formed and has obtained a consolidated land tenure certificate for
the entire irrigated area, it is expected to apply for an extension of the existing water
permit to cover the additional lands represented by the Mgongola irrigation scheme.
That permit would increase the water right to 1.4 m3/s during the rainy season (an
additional 0.776 m3/s).

4.2 Piped Main Canal Alternative

The Piped Main Canal alternative differs from the Proposed Action only in that it
constructs a piped main canal, thus reducing evaporation from the main canal. The

5 CROPWAT is a decision support tool developed by the Land and Water Development Division of the
Food and Agriculture Organization of the United Nations for calculation of crop water requirements
and irrigation requirements based on soil, climate and crop data.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-20
objective of this alternative is to improve the conveyance efficiency and thus
conserve water.
During preparation of the EA, several piped alternatives were analyzed, including
piping both the main and secondary canals and using steel and concrete piping. The
alternative of using steel pipes and piping only the main canal was determined to be
the most effective piping alternative. Although the unit costs for concrete pipes are
cheaper than steel pipes for all but diameters less than 450 mm, steel pipes are more
easily jointed, are lighter for making the necessary river crossing, and are effectively
impermeable. There are numerous problems associated with reinforced concrete
pipes and these tend to increase with the diameter of the pipe. In addition, concrete
pipes cannot be expected to hold pressure even at low heads, and the piped main
canal will be under about 6 m of pressure at some locations. Although steel pipes
may suffer from corrosion, in the Mgongola area this is not seen as a major concern.
The Piped Main Canal alternative has an estimated cost of $5,695,000. Conveyance
efficiency is expected to be 92% (weighted average by length: 97% for the Main
Canal, 85% for the Secondary Tertiary canals) and application efficiencies are
expected to be 60%. This gives an overall expected irrigation efficiency of 55%.
The General Construction Activities, Flood Control, Farm Roads, Demobilization, and
Cropping specifications will be the same as those for the Proposed Action. The
specifications for Irrigation and Drainage Components; Operation, Maintenance and
Management; and Irrigation Water Requirements and Water Rights will be different,
as noted below.
4.2.1 Irrigation and Drainage Components
The specifications for secondary canals, drains and incidental land levelling will be
the same as for the Proposed Activity. The rehabilitation of the main canal, however,
will be as follows:
 Piping the main canal from the diversion to the Mkindo Scheme to the end
of the main canal;
 Construction of a settling basin to trap and remove sediment before it
enters the pipe;
 Furnishing and installing a single 1-meter diameter steel pipe set on a
gravel bed within the alignment of the main canal in the Proposed Action
with manholes at a minimum of 500 m; and
 Construction at each secondary canal offtake of a manhole, a flow
measurement device, and a sliding gate to control outflow.
4.2.2 Operation, Maintenance and Management
The Operation, Maintenance and Management specifications for the Piped Main
Canal alternative are the same as those for the Proposed Action with the addition of
the following:
 Large diameter pipes are relatively easy to inspect internally and adequate
access points will be provided. However, maintenance staff will need to
be fully trained on confined space entry, and equipped with generators,
lighting and breathing apparatus in order to carry them out safely.
 The day-to-day operation of the enclosed conduit should be easier than an
open channel and less maintenance such as desilting and channel
clearance will be required. However, if sediment does enter the pipe then
ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-21
 its removal will be a major undertaking, particularly since the pipe has only
a 1-meter diameter.
 Special care must also be taken to prevent the growth of bushes or trees
whose roots may penetrate the pipe joints.
4.2.3 Irrigation Water Requirements and Water Rights
The overall irrigation water efficiency of the Piped Main Canal alternative is 55%,
which is 2% more efficient than the Proposed Action. This will reduce the irrigation
water requirement by 0.043 m3/s, reducing the required additional water right to
0.733 m3/s.6

4.3 Sprinkler Irrigation Alternative

The Sprinkler Irrigation alternative is the same as the Proposed Action with the
addition of 17 pumping points at in the tertiary canals to allow portable diesel pumps
to pressurize small hand-moveable sprinkler irrigation units covering individual
basins. Each pumping point will be capable of serving an area of approximately 36
ha.
A sprinkling alternative has been included to secure greater irrigation efficiency for
the scheme. A system-wide pressurized sprinkling alternative was also evaluated
(see Section 4.7.1), but this modular approach as an add-on to a flood irrigation
system was more cost effective and allows flexibility for implementation. With
portable pump sprinkling, individual farmers or small groups of farmers can choose to
adopt the technology without having to get concurrence from a majority of the
cooperative members. It also allows farmers to flood irrigate if the portable
equipment is inoperable.
The Sprinkler Irrigation alternative would have an estimated initial construction cost
of $5,423,000. In addition, separate, portable pumping units capable of servicing 36
hectares would have to be purchased by farmers at a cost of $105,000 each
($2,917/ha). The Sprinkler Irrigation alternative will begin with the same irrigation
water efficiency as the Proposed Action, but these efficiencies will increase over time
as farmers purchase and use sprinklers. Ultimately, if sprinkling units were
purchased for the entire 589 hectares, the total cost would be $7,208,000. It would
have an irrigation water conveyance efficiency of 97%7 and application efficiencies of
75%, which gives an overall expected irrigation efficiency of 73%.
The General Construction Activities, Flood Control, Farm Roads, and Demobilization
specifications will be the same as those for the Proposed Action. The specifications
for Irrigation and Drainage Components; Cropping; Operation, Maintenance and
Management; and Irrigation Water Requirements and Water Rights will be different,
as noted below.
4.3.1 Irrigation and Drainage Components
The Sprinkler Irrigation alternative has all of the same Irrigation and Drainage
Rehabilitation specifications of the Proposed Action plus the following:
 Installation of a simple water meter at 17 tertiary canal head regulator; and

6 The improved efficiency will only apply to the 589 ha of newly irrigated land.
7 Higher than the Proposed Action due to the use of PVC piping for Tertiary Canals.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-22
  Construction of a concrete pumping point (sump) at each of these tertiary
canals in line after the water meter.
In addition, this alternative assumes that the farmers will have to pay for the portable
sprinkling unit capable of servicing a 36-hectare area. Each unit would consist of:
 Mobile diesel engine and suction pump to 6 bar;
 Sprinkler and 2-m riser;
 200-mm diameter unplasticized polyvinylchloride (uPVC) or pressure pipe;
 50-mm diameter PE pipe; and
 Couplings.
4.3.2 Operation, Maintenance and Management
The Operation, Maintenance and Management specifications for the Sprinkler
Irrigation alternative are the same as those for the Proposed Action with the addition
of the following:
 Irrigation using hand-move sprinklers is a time-consuming and labor-
intensive activity as someone must be on hand to move the sprinkler after
each set. In practice one person could handle the sequential movement of
10 laterals resulting in one 9-ha basin being irrigated in 6 hours; however,
the process must continue over night if the minimum system sizing is to be
maintained. Each basin would then need to be irrigated every 4 days and
thus one person could manage 36 ha of irrigation.
 To maximize water conservation it has been assumed that dry-foot rice will
be grown (no ponding of water). This will mean that additional labor will
be required to weed the rice and/or additional herbicides (in comparison
with paddy rice cultivation) must be used to control broad-leaf weeds.
 The Sprinkler Irrigation alternative provides groups of WUA members with
the option of using sprinklers, by providing pumping points at 17 tertiary
canals to allow portable diesel pumps to pressurize small hand-moveable
sprinkler irrigation units covering individual basins. The project, however,
does not provide the pumps or sprinkler systems. So farmers cultivating
36 contiguous ha with access to one of the 17 pumping points will have to
join forces to purchase the necessary pumping equipment, at a cost of
$2,917/ha.
These additional management issues are a radical departure from the current
irrigation system used in the Mgongola area, on the Mkindo schemes. Introducing
such a radically different system would take considerable extension work and
training. Without an extension program, it is unlikely that any farmers would adopt
the sprinkler technology. This EA does not include a description of or the cost for
such an extension program.
A benefit of this sprinkler approach is that it is an add-on to a flood irrigation system,
so farmers do not have to make the transition immediately, or all at the same time.
Indeed, the sprinkling system can be implemented on 36 hectares at a time, allowing
early adopters to move forward, while more conservative farmers continue with the
current practices.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-23
In addition, this alternative requires farmers to invest in sprinkler systems for its
implementation, but until farmers are able to see tangible benefits associated with
managing water efficiently there is little incentive for them to make such investments.
Maximum irrigation efficiency seldom comes until a realistic charge is levied for water
consumption. If the WUA sets up a fee/water use rather than a fee/ha fee structure,
the incentives for using irrigation water efficiently will be established. However, this
is a highly contentious issue in Tanzania where farmers are used to receiving their
water for a nominal fixed fee per hectare to recover system operation and
maintenance costs.
4.3.3 Cropping
“Long straw” rice varieties of the type preferred by local farmers are likely to be
inappropriate for sprinkler irrigation unless overhead sprinklers are adopted or else
low-drift sprinklers used. Standard sprinklers “throw” the water sideways where it is
likely to knock over long-straw varieties (aka “lodge”). Lodged rice can result in
reduced yield potential. It is harder to harvest mechanically because it must first be
picked up off the ground. One solution to this would be to convert to overhead
moveable irrigation systems or else grow shorter varieties of rice.
 Overhead moving systems (linear move) would be difficult to transport
from one basin to the next but would offer substantial savings in effort with
regard to moving sets of individual sprinkler laterals about. However, this
system is substantially more expensive to buy and maintain and the
moveable tires supporting the towers of the boom may become bogged in
the black cotton soils of the Dakawa farm.
 Short-straw rice varieties offer many potential benefits to the farmers such
as a reduced growing season (90 days in comparison with 120-150 days)
and potentially higher yielding; however, they are generally not aromatic,
so farmers and the local people do not like them. Nevertheless, there is a
great potential for export if this mindset can be changed.
Local farmers produce rice for personal consumption (subsistence) as well as for the
market. The local farmers prefer the taste of the “long straw” rice. As will changing
the irrigation system, changing the type of rice grown will also require considerable
extension work and training.
4.3.4 Irrigation Water Requirements and Water Rights
Farmers will initially require the full amount of irrigation water necessary for growing
rice using flood irrigation, so in the initial stages of operation, this alternative will have
the same irrigation water requirements as the Proposed Action. But as farmers
group together and purchase and install sprinkler systems, their water use efficiency
will increase from 53% to 73%. If all of the farmers in the 589 ha of newly irrigated
area install sprinkling systems, the overall the irrigation water requirement would be
re reduce by 0.32 m3/s, reducing the required additional water right to 0.456 m3/s.

4.4 SRI Alternative

The System of Rice Intensification (SRI) alternative has the same irrigation
infrastructure as the Proposed Action, however, cultivation practices and water
management will follow SRI prescriptions.
SRI is an irrigated rice cultivation system developed in the 1980s by the French
Jesuit Father Henri de Laulanié in Madagascar. It was subsequently refined and
promoted by such institutions as the College of Agriculture and Life Sciences at

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Cornell University and the International Fund for Agricultural Development. It has
been implemented in 50 countries. It was introduced in East Africa in Rwanda in
2008 and subsequently in Kenya, Burundi, and Tanzania (Katamba et al. 2013).
The SRI cultivating system consists of:
 Growing seedlings in nurseries.
 Transplanting 8- to 12-day-old seedlings.
 Planting only one seedling per hill in hills spaced widely apart in a grid.
 Controlling weeds with a rotating hand hoe, which also aerates the soil.
 Applying compost to increase the soil’s organic matter content.
 Using Alternating Wet/Dry (AWD) irrigation application.
The SRI alternative has the same estimated cost as the Proposed Action,
$5,695,000. This cost, however, does not include the cost of a multi-year extension
program to promote SRI among the participating farmers. Such a program has not
yet been designed, so the potential cost has not been estimated. The SRI alternative
may begin with the same irrigation water efficiency as the Proposed Action, as
farmers will be familiar with the practices used in the area by other irrigators,
however, the efficiencies could rapidly increase as farmers adopt SRI practices.
Ultimately, if all farmers adopt SRI, conveyance efficiency is expected to be 88%
(weighted average by length: 90% for the Main Canal, 85% for the Secondary and
Tertiary canals) and application efficiencies are expected to be 80%. This gives an
overall expected irrigation efficiency of 70%.
The General Construction Activities, Irrigation and Drainage Components, Flood
Control, Farm Roads, and Demobilization specifications will be the same as those for
the Proposed Action. The specifications for Cropping; Operation, Maintenance and
Management; and Irrigation Water Requirements and Water Rights will be different,
as noted below.
4.4.1 Operation, Maintenance and Management
The Operation, Maintenance and Management specifications for the SRI alternative
are the same as those for the Proposed Action with the addition of an intensive,
multi-year agricultural extension program in cooperation with MZITSU to promote SRI
practices among the Mgongola irrigation scheme farmers.
Although implementation of SRI has been able to demonstrate improved yields (at
least in relation to traditional practices) with less use of water and other agricultural
inputs (seed, chemical fertilizers and pesticides), it has not been readily adopted by
rice farmers both abroad (Berkhout and Glover 2011) and in Tanzania (Katambara et
al. 2013). In general there are several reasons for low adoption rates, but key among
them are risk aversion and costs.
Adopting a new cultivation practice is a risky venture, particularly for a low-income
subsistence farmer for whom a bad result could mean famine. Cost is another critical
barrier, particularly for the low-income subsistence farmer. In the case of SRI, there
is little upfront cost to be borne, but there is increased labor in development of
nurseries and seedling planting for those farmers who currently directly broadcast
seed in their fields (as is the case in the Mgongola project area). There is also
increased labor involved in weed control.
In the case of SRI, another critical barrier to adoption is that many of its practices run
contrary to “best management practices” for paddy rice production that have been

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promoted for years. These include the age and number of seedlings planted in hills,
the spacing of the hills, the irrigation water management regime, the use of only
compost for fertilizer, and relying on hand-weeding rather than herbicides for weed
control. This can make SRI appear to be a controversial cultivation scheme (and
indeed, it has been controversial in the literature), and if the local experts (extension
officers) are not supportive, then it is very difficult to implement.
These barriers can be overcome, but only with a concerted, multi-year extension
program operated in conjunction with local government extension agents. Such a
program is beyond the current scope of IRRIP1. To implement this program, USAID
will need to expand the scope of IRRIP1 to include such a program or use another
vehicle such as NAFAKA to do the same. NAFAKA began conducting SRI activities
in Mvomero and Kilombero Districts in 2011 and would provide USAID with a vehicle
for pursuing an SRI extension program for the Mgongola irrigation scheme. Such a
program would be in-line with the GoT’s SAGCOT Agriculture Green Growth (AGG)
initiatives.
This EA does not present a description of or cost for the extension program, as it has
not yet been designed. Whatever program is designed it should conform to the AGG
characteristics as shown in Table 4.6.

Table 4.6: Characteristics of AGG Extension

Characteristics of AGG Farming Systems Corresponding Extension Needs

Extension should include ample on-farm
demonstrations, as farmers need to “see it to
AGG systems may be seen by farmers as believe it”
radically different from existing/conventional
practice, and thus risky Extension must harness and strengthen
knowledge sharing about farming practices
based on trust and peer relations
AGG systems are knowledge intensive, based Extension must teach principles of agro-
on managing the farm as an agro-ecosystem ecosystem management
Extension should spend a high proportion of
Farming systems are adapted to each local their time in the field, helping farmers use local
context, not a simple “cookbook” prescription knowledge to decide how to fine-tune practices
to local conditions
Extension should include mechanisms to help
AGG is an adaptive approach that responds to
farmers experiment for continual improvement
changing conditions
and problem-solving
Extension curricula should include basics of
Productive agriculture is predicated on sound
soil, water, forest, grassland, and/or wetland
natural resource management
management
Extension programs should be linked closely to
The best AGG solutions sometimes require universities and regional and international
bringing in new ideas, technologies, or research and support centres, and
practices from outside the district or even the extensionists should receive frequent refresher
country courses in new principles, practices, and
technologies
Source: Milder et al. 2012, pg. 39

4.4.2 Cropping
The SRI alternative will, like the Proposed Action, grow paddy rice. The rice,
however, will be cultivated in a significantly different manner. SRI is based on five
components (SRI-RICE 2014):

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  The use of nursery-grown seedlings (as opposed to the current practice of
no nurseries). It can be used with any variety of paddy-rice (i.e., it is not
limited to improved varieties).
 Planting seedlings in the fields (as opposed to the current practice of
broadcast seeding):
o when they are 8-12 days old (as opposed to the conventional
improved practices recommendation of 21-30 days);
o one per hill (as opposed to the conventional improved practices
recommendation of 3-5 seeds per hill); and
o on a grid at wide spacing (25 cm x 25 cm as opposed to the
conventional improved practices recommendation of hills in rows 10
to 15 cm apart).
 Use of organic fertilizer (compost), although many reports indicate that
farmers using SRI generally supplement with urea.
 Reduced water use:
o Field flooded at 1-2 cm after transplanting, and maintained until plants
are ~10 cm tall (~10 days after transplanting).
o Alternating Wet/Dry (AWD) water management during most of the
growing season, where fields are periodically flooded, but then
allowed to “dry” out between flooding (just dry on the surface, so that
the roots stay moist). A Kenyan government brochure recommends a
cycle of 3 days of 1-2 cm ponding followed by 7 days of drying (Mati
2012).
o When flowering begins, a thin layer (1-2cm) of water is applied and
maintained on the field for 2-3 weeks.
o Then back to the AWD.
o 2-3 weeks before harvest irrigation stops to allow the field to dry for
harvest (same as conventional practices) (need drainage system to
remove water)
 Hand weeding. Due to the lack of ponding, weeds will be a
problem. Weeding is done with a special, hand held rotary-head weeder
to remove weeds, aerate the soil and improve field leveling. Some SRI
farmers, however, still use herbicides.
Some proponents of SRI claim that its adoption has increased yields per ha by 2-3
times. But many researchers have challenged these results as being based on
unscientific studies and lack of definition of baseline yields. These researchers have
conducted studies that show that the yield increases from SRI are no better than
what can be gained with conventional best practices (improved seed, transplanting,
and proper fertilizer and herbicide use) with conventional rice irrigation (Bouman et
al. 2007, McDonald et al. 2006).
4.4.3 Irrigation Water Requirements and Water Rights
Proponents and detractors alike, however, concur that SRI uses less water for
production, with reported reductions ranging from 15 to 50% (with even critics
reporting 15 to 30% reductions in water use without significant impact on production
[Bouman et al. 2007 pg. 20]). There also seems to be agreement that SRI requires
more labor (primarily due to weeding and spreading organic fertilizers) but reduces
the quantity needed of seed per ha.

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-27
This EA uses a mid-range estimate of a 25% reduction in in-field application needs.
This results in a reduction of 0.287 m3/s, reducing the required additional water right
to 0.489 m3/s.

4.5 Improved Intensified Rain-Fed Agriculture Alternative

The Improved Intensified Rain-Fed Agriculture alternative would not build an
irrigation infrastructure in the Mgongola Project area. Instead of providing irrigation,
this alternative would provide an extension program to promote improved agricultural
practices to the farmers in the area. The program would probably be similar to that
promoted by the FAO in the area in the 1990s, which included promotion of the use
of improved seeds, best management cultivation practices, and proper use of
fertilizers and pesticides, and would incorporate components that have been
promoted by NAFAKA.
This EA does not present a description of or cost for the Improved Intensified Rain-
Fed Agriculture alternative program, as it has not yet been designed. Whatever
program is designed it should conform to the AGG characteristics as shown in Table
4.6.
The Improved Intensified Rain-Fed Agriculture alternative would have no General
Construction Activities, Irrigation and Drainage Components, Flood Control, Farm
Roads, Demobilization or scheme Operation and Maintenance specifications, as it
will involve no irrigation scheme development. The irrigation and water rights
specifications will be null.
As noted in Section 3.3, the Mgongola irrigation scheme was identified by the GoT
for inclusion in the FTF. The GoT views the development of the Mgongola irrigation
scheme as:
one of the important inputs for achieving the implementation of KILIMO
KWANZA, National Strategy for Growth and Reduction of Poverty
NSGRP (MKUKUTA), Millennium Development Goals (MDGs) and
Tanzania Development and Vision (TDV) 2025. (MWI 2010, pg. 7)
The GoT has conducted its own studies of the proposed project as well as having
participated in studies funded by donor agencies (MWI 2010, JICA 1998). The GoT
has also moved forward on developing a WUA to manage the scheme, including the
proposed dissolution of the Mkindo cooperative and incorporating its members into
the new WUA.

4.6 No Action Alternative

The No Action alternative means that USAID would not construct the Mgongola
irrigation scheme nor implement an improved rain-fed agricultural project. In this
case, the local farmers would continue to grow rain-fed paddy rice using their
traditional practices. There would be no improvement in farming practices or access
to fields. Rice yields would remain low and would fluctuate dramatically depending
upon annual variation in rainfall and flooding.

4.7 Alternatives Eliminated from Analysis

The following key factors were used to initially assess potential alternatives for the
Mgongola irrigation scheme, in the assessment:
 Technical/design factors – canals, drains, structures, pumps, etc.
 Environmental factors – impact of the rehabilitation approaches on the
environment (water resources, ecosystems, habitats, etc.);
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-28
  Operation and management factors – issues relating to the ability of the
WUA to manage the infrastructure, and the desirability of the proposed
alternatives from the beneficiaries’ perspective; and
 Cost – capital investment and long-term operating costs of the
alternatives.
Applying these factors, the following alternative was eliminated from further analysis.
4.7.1 Full Sprinkler Irrigation with Central Pumping
The Full Sprinkler Irrigation with Central Pumping alternative would install a fully
pressurized irrigation layout covering the Mgongola project area. This alternative
would require a design incorporating pumps capable of delivering the maximum
design head. The pipe network incorporates a closed braced ring main which allows
smaller/cheaper pipe diameters to be used and pressures to be maintained at the top
and bottom of the sub-main pipe lines (secondary canals). The ring main system and
bracing also allows for elements of the scheme to be isolated for maintenance
without closing the whole network. The design incorporates a filtration unit to remove
sand and sediment.
With this alternative, the Project would provide the irrigation distribution system (from
pump station through to tertiary manifolds) but farmers would be expected to supply
the more consumable items such as laterals and sprinkler heads. The project cost,
therefore, would be $8,639,000. Farmers would have to pay an additional $550 per
hectare for aluminum laterals and sprinkler heads (this cost could be reduced
somewhat by using lay-flat hosing or polyethylene pipe but at the cost of durability).
The total cost (including the cost of laterals and sprinklers) for the entire 589-hectare
area would be $8,963,000.
Conveyance efficiency would be expected to be 97% throughout the project area with
application efficiencies of 75%. This gives an overall expected irrigation efficiency of
73%.
This alternative has the same Operation, Maintenance and Management
specifications as the Sprinkler Irrigation alternative, but it would not allow for gradual
implementation; rather, the full 589 hectares would have to move to sprinkler
irrigation at the commissioning of the system.
Reason for Eliminating this Alternative from Further Analysis
This alternative would result in the second highest irrigation efficiency of all
alternatives initially considered, however, it was eliminated from further analysis due
to the high capital costs (the highest), the need for each farmer in the WUA to come
up with $550/ha to purchase laterals and sprinklers, and more importantly, the radical
change in irrigation, cropping, cultivation, operation and maintenance practices that
would be required by every farmer in the WUA at the time of commissioning.

4.8 Mitigation Measures

This section of the EA presents general mitigation measures. Specific mitigation
measures are presented in Section 7.1. Due to the fact that the Proposed Action
and all of the irrigation alternatives deal with construction of an irrigation scheme on
the same piece of land, all of the mitigation measures are the same, for both
mobilization and construction and operation.
The mitigation measures for mobilization and construction are presented in Table
4.7. The Improved Intensified Rain-Fed Agriculture alternative will not have

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-29
mitigation measures during mobilization and construction, as there will be no
mobilization and construction.
The mitigation measures for the Proposed Action and all action alternatives during
operation are the same, except for water quantity available to downstream users and
water use conflicts. The mitigation measures associated with these two impacts are
not necessary for the Improved Intensified Rain-Fed Agriculture alternative. The
mitigation measures for the action alternatives during operation are presented in
Table 4.8.

Table 4.7: Mitigation Measures for Mobilization and Construction Common

to the Proposed Action and All Irrigation Alternatives
Impact General Mitigation Measure
Minimize disturbed area
Implement erosion control measures
Soil Erosion Obtain borrow material from approved and mostly existing sites
Properly close borrow areas after use
Revegetate at the end of construction
Maintain vehicles and equipment
Soil Pollution Develop and implement a Hazardous Materials Management Plan
Develop and implement a Solid Waste Management Plan
Loss of Topsoil Stockpile, store and replace topsoil
Implement erosion control measures
Obtain borrow material from approved and mostly existing sites
Develop and implement a Hazardous Materials Management Plan
Water Contamination
Develop and implement a Solid Waste Management Plan
Provide pit toilets for workers
Revegetate at the end of construction
Solid Waste Develop and implement a Solid Waste Management Plan
Generation
Properly maintain vehicles and equipment
Dust and Air Pollution
Water sprinkling for dust control
Muffler equipped vehicles and equipment
Noise Pollution
Construction management of working hours
Implement erosion control measures
Obtain borrow material from approved and mostly existing sites
Effects on the Aquatic
Develop and implement a Hazardous Materials Management Plan
Species
Develop and implement a Solid Waste Management Plan
Revegetate at the end of construction
Displacement of Schedule construction activities to minimize impacts on current
economic activities farming activities.
Develop and implement procedures for respectfully handling the
Disturbance of graves
disturbance of any grave sites encountered during construction.
Develop and implement a Health and Safety Program
Worker/Community
Health and Safety Provide workers with personal protective equipment and training in
its use.
Change of Community Sensitize community members
Lifestyle Instruct workers on expected, proper behavior

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Table 4.8: Mitigation Measures for Operation
Impact General Mitigation Measure
Soil Salinity (Sprinkler Monitor soil salinity at the end of each irrigation season and take
Irrigation) remedial actions if salinity reaches critical levels.
Effects of Pesticides and Implementation of the NAFAKA PERSUAP
Fertilizer Use Sensitization of farmers on fertilizer use
Same as for Effects of Pesticides and Fertilizer Use
Water Contamination Periodic water quality monitoring downstream of drainage
discharges
Water Quantity Impacts to
Downstream Users and Monitor water withdrawals by Mgongola irrigation scheme
Ecosystems (Irrigation Monitor downstream flows
Alternatives)
Effects on Aquatic Same as for Effects of Pesticides and Fertilizer Use
Species Water quality monitoring downstream of drainage discharges
Create a livestock corridor providing access to rivers in dry season
Designate grazing and watering areas outside of the project
Land Use Conflicts –
boundaries
Cultivation/Grazing
Establish an NGO composed of farmers and herders to address
cultivation/grazing conflicts
Scheme Management
Capacity (Irrigation Develop and implement a capacity building program for the WUA
Alternatives)
WRBWO Capacity to Continue capacity building for the WRBWO.
Control Water Deploy and pilot the use of remote instrumentation for monitoring
Abstractions (Irrigation flows, abstractions, discharges etc. on the Mkindo River and the
Alternatives) Mtibwa EFA site

4.9 Comparison of Environmental Impacts of Alternatives

This subsection presents the results of the impact assessment presented in
Sections 6.2 and 6.3.2.1 of this EA. As mentioned in the previous section, the
Proposed Action and all of the irrigation alternatives will construct the same size
irrigation scheme on the same piece of property. They will also be constructed on
the same alignments. Therefore, the Proposed Action and all of the irrigation
alternatives will have the same environmental impacts during mobilization and
construction (Table 4.9), and all of these impacts will be mitigated in the same way
as described in Table 4.7. With the implementation of the mitigation measures, all of
the impacts of mobilization and construction will be minimal and none of them will be
significant.
The Improved Intensified Rain-Fed Agriculture alternative will have no impacts during
mobilization and construction, as no construction is required for its implementation.
The environmental impacts during operation, however, are anticipated to differ
between the Proposed Action and its alternatives due to the differences in their
designs. These differences have been expressed both quantitatively (Table 4.10)
and qualitatively (Table 4.11). All of these impacts, except the impact on
downstream water users, will be mitigated as described in Table 4.8. With the
implementation of the mitigation measures, all of the impacts during operation,
except the impact on downstream water users, will be minimal and none of them will
be significant.

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-31
 Table 4.9: Environmental Impacts Associated with Mobilization and
Construction
Positive Impacts
Opportunities for Temporary
Employment
Negative Impacts
Soil Erosion Soil Pollution Loss of Topsoil
Water Contamination Solid Waste Generation Dust and Air Pollution
Noise Pollution Effects on the Aquatic Species Worker/Community Health
Change of Community and Safety
Lifestyle

Table 4.10: Quantitative Comparison of the Impacts of Alternatives During

Operation

ALTERNATIVES
Piped
Proposed Main Sprinkler Improved No
Impact Action Canal Irrigationa SRIa Rain-Feda Action

Cost ($1,000,000)b 5.0 5.7 5.4-7.2 5.0 NA 0

Rice Production (mt/ha)
At turnover 3.2 3.2 3.2 3.2 1.6 1.6
With Extension Programc 4.9 4.9 4.9 4.9 3.2
Conveyance Efficiency 88% 92% 88-97% 88% NA NA
Application Efficiency 60% 60% 60-75% 60-80% NA NA
Overall Efficiency 53% 55% 53-73% 53-70% NA NA
Water abstraction for new
589 ha (m3/s) 1.18 1.14 0.86-1.18 0.89-1.18 NA NA

% of RADd -40 to -41 to

-51% -50% -12% -12%
-51% -51%
Notes:
a
Several of the impacts will increase over time, assuming that farmers adopt the improved system
(Sprinkling, SRI, or Improved Rain-Fed Cultivation).
b
Cost is only for construction of the irrigation infrastructure and training in its use. It does not
include the cost for extensions services for rice cultivation.
c Provision of extension services is optional for the Proposed Action, and the Piped Main Canal
alternatives. Extension services are required for implementation of the Sprinkler Irrigation,
SRI and Improved Rain-Fed alternatives.
d
Percent of Recommended Average Discharge at the Mtibwa EFA location given the withdrawal of the
irrigation requirement for the period of greatest impact (2nd half of March). Data from Table 6.2 and its
supporting analyses.

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Table 4.11: Qualitative Comparison of the Impacts of Alternatives

ALTERNATIVES
Piped
Proposed Main Sprinkler Improved No
Impact Action Canal Irrigation* SRI Rain-Fed Action

Reliable Supply of
+2 +2 +2 +2 0 0
Irrigation Water
Opportunities for
+2 +2 +2 +2 +1 0
Employment
Improved Market
Outlets
+2 +2 +2 +2 0 0

Reduced Water Logging +2 +2 +2 +2 0 0

Reduced Flooding +2 +2 +2 +2 0 0
Soil Salinity 0 0 -1 0 0 0
Effects of Pesticides and
-1 -1 -1 0 -1 0
Fertilizer Use
Water Contamination -1 -1 -1 0 -1 0
Effects on Aquatic
-1 -1 -1 0 -1 0
Species
Land Use Conflicts –
-2 -2 -2 -2 -1 0
Cultivation/Grazing
Scheme Management -1 -1 -1 -1 0 0
WRBWO Capacity to
Control Water -1 -1 -1 -1 0 0
Abstractions
Change in Community
+2 +2 +2 +2 +1 0
Lifestyle
Rankings: -2 Strong adverse effect
-1 Adverse effect
0 Neutral or no change
+1 Positive effect/benefit
+2 Strong positive effect/benefit

Note:
* Ranked assuming that all farmers adopt sprinkler irrigation, otherwise this alternative has the same
impacts as the Proposed Action.

IRRIP1 conducted an analysis (Annex D) of the impacts of water withdrawals on

downstream users (human and ecological) on the Wami River using the
environmental flow assessment studies and the best information available on
expected low flows and current and future abstractions. That analysis indicates that
there will be a significant immitigable impact on downstream users in two periods (2nd
periods of March and June) from the withdrawals associated with any of the irrigation
alternatives. This impact exists, but at a lower magnitude, for the non-irrigation
alternatives as well (Improved Intensified Rain-Fed Agriculture and No Action),
indicating that this is an existing condition caused by planned over allocation of the
flow to other users. The non-irrigation alternatives will not aggravate that existing
condition.
In summary, all of the irrigation alternatives will result in significant, immitigable
impacts on downstream water users, both human and ecological. The driving force
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-33
behind this outcome is the planned future water consumption needs of the Mtibwa
Sugar Estate. Short of reducing the water rights for the Estate, these impacts cannot
be mitigated. Reducing the rights is unlikely considering the substantial capital
investments the Estate has made and plans to make to use those rights, and the
apparent inability of the WRBWO to allocate rights based on the EFA, in spite of their
stated intention to do so (WRBWO 2015).

4.10 Preferred Alternative

Due to the existence of immitigable significant impacts on downstream water users
associated with all of the irrigation alternatives, USAID/Tanzania has selected the
Improved Intensified Rain-Fed Agriculture alternative as the preferred alternative
instead of the Proposed Action.

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 4-34
5 AFFECTED ENVIRONMENT
As required in 22 CFR 216.6(c)(4), this section presents a succinct description of the
environment in the project area that may be affected by the Proposed Action and its
alternatives.

5.1 Boundaries
The project covers the construction of an irrigation scheme in Mgongola as shown in
Figure 3.2. The special boundary of the project and its alternatives for most of the
physical and environmental impacts will be limited to the 620-ha area. However, the
project’s impacts on water resources may influence the downstream environmental
flows and water users in the Wami River Basin (Figure 5.1), extending the spatial
boundaries for the water resources analysis well beyond the project boundaries.

Figure 5.1: Wami River Basin

Source: Wami-Ruvu Basin Water Office
Note: Ruvu and Coast Basins also shown

The social impacts will be primarily borne by four nearby villages – Mkindo, Dihombo,
Hembeti, and Kambala – and secondarily by the Hembeti Ward in the Mvomero
District. So the boundary for the socio-economic analysis will be the four villages and
the Hembeti Ward.
Temporal boundaries refer to project life span and the reversibility of impacts. The
irrigation infrastructure is anticipated to have a design life of between 30 and 50
years, assuming proper maintenance, management and upkeep. After that time
period, the scheme will require other major works to be carried out. However, the
immediate mobilization and construction activities are anticipated to occur over a 20-
month period.

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5.2 Physical Environment
5.2.1 Topography
The irrigation scheme lies on the Mkata Flood Plain, between the Mkindo and
Dizingwi river to the north and the Mgongola River to the south (between latitudes
37o32’E and 37o36’E and longitudes 6o16’S and 6o18’S). Elevation ranges from 345
m to 365 m above sea level. The terrain is generally flat with an overall slope of
1/200 to 1/500 to the east. It is subject to flooding during the rainy season (February-
June). According to interviews with local farmers of the area, annual flood water
depth is approximately 0.3 m on the Mkindo River and 0.5 m to 1.0 m on the
Mgongola River.
5.2.2 Geology and Soils
The project area lies on the border of an area composed of igneous and
metamorphic rocks overlain by more recent sedimentary rocks same as those found
in Mwinyi, Merela and Kwambe quarry sites. The rock and stone materials from
these sources are suitable for making aggregates for concrete and gravel wearing
course.
Soil mapping was conducted for the feasibility study (JICA 1998). The soils that were
encountered were classified according the FAO/UNESCO soil classification:
 Eutric Cambisols (Mapping unit Mgl-l)
 Eutric Fluvisols (Mapping unit Mgl-2)
 Eutric Fluvisols associated with Eutric Gleysols (Mapping unit Mgl-3)
The characteristics of these soils and their presence in the surveyed area are
presented in Table 5.1. The feasibility study (JICA 1998) concluded that the soils
were more suitable for paddy rice production than for any other crop.
Mgl-1 soils are the most prominent soils, comprising about 86% of the area within the
project boundaries. These soils are currently used for and well suited for paddy rice
production.
The Mgl-3 soils are less common within the project boundaries, only occurring in a
narrow strip on the southern boundary and comprising about 7% of the area. The
existing Mkindo irrigation schemes are predominantly on the Mgl-3 soils, and they
have proven to be well suited for irrigated paddy rice production. In their natural
state, the location of a high ground water table where these soils occur prevents
them from draining freely, especially during the rainy season. This poor drainability
does not negatively impact paddy rice production, which thrives with water ponding.
The Mgl-2 soils in the project area are located in two small areas on the western
boundary and near the southeastern boundary and comprise about 7% of the total
area. Although still suitable for rice production, the Mgl-2 soils are more permeable
than the other two classes.
Most of the land in the project area is periodically flooded during the rainy season
(February-June) by the surrounding rivers. During the dry season, these areas dry
up quickly with soils developing deep and wide cracks on the surface.

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 Table 5.1: Soils in Mgongola Irrigation Scheme Area

Mapping Units Mgl-1 Mgl-2 Mgl-3

Eutrophic Fluvisols
Eutrophic
Soil Unit Eutrophic Fluvisols associated Eutric
Cambisols
Gleysols
River Plain/Natural
Physiography Alluvial Plain Old Natural Levees
Levees
Topography Flat Flat to Almost Flat Flat to Almost Flat
Parent Material Alluvium Alluvium Alluvium
Soil Characteristics
- Texture* CL/C/C SL-SCL/SCL/C SCL-SL/L/SL
- Depth >150 cm >150 cm >150 cm
- Fertility High High High
Drainability Imperfect Well Poor
Depth of Groundwater
- Rainy season Flooding 30–100 cm Flooding
- Dry season >150 cm >150 cm 50–150 cm
Land Use Paddy Grassland** Paddy, Grassland**
Notes:
* Texture abbreviations: C=Clay, L=Loam, S=Sand, CL=Clay Loam, SL=Sandy Loam,
SCL=Sandy Clay Loam
** In the Scoping Statement the land uses for these two soil types were incorrectly
reported.
Source: JICA 1998, pg. D-III-5

5.2.3 Climatic Conditions

The Mvomero District is characterized by high rainfalls between March and May and
from October to December when predominantly eastern trade winds bring moisture
from the Indian Ocean. Annual rainfall is between 600 mm and 2,000 mm, being
lowest at the foothill and highest between 400 m to 2,000 m altitudes above sea
level. There is no weather station at the Mgongola project area, but the rainfall
pattern there is similar to that at the nearby Morogoro Town weather station (Figure
5.2 and Figure 5.3), which is at the same altitude (500 m) as the project area.
Temperature ranges from 18-30 °C.

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 Figure 5.2: Annual Rainfall in Morogoro Town, 1922-1988
Source: Wami-Ruvu Basin Water Office

Figure 5.3: Annual Rainfall in Morogoro Region, 1980-2006

Source: Wami-Ruvu Basin Water Office

Morogoro Region lies between the central highlands and the coastal region and it will
experience a mixture of impacts related to climate changes. The USAID-funded
Integrated Water, Sanitation and Hygiene (iWASH) Program has conducted climate
change and climate vulnerability assessments for the Wami Basin. It has released a
draft interim report, “Climate in the Wami and Ruvu Basins, Tanzania: Current
Characteristics and Future Projections” (iWASH 2013b). A review of that report
indicates climate change will cause no appreciable decrease in historical rainfall but

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will increase uncertainty on its onset and regularity. This concurs with other available
climatological data and existing hydrological studies, indicating there does not appear
to be any evidence of a long-term downward trend in rainfall.
The region also already experiences significant climate variability. The region has
been affected by droughts about once in 4 years. Relatively recent droughts have
occurred for example in 1999-2000, 1996-97, 1992, 1987, 1985, 1983, 1975-76 and
1971 but with slight increase of rainfall in year 2006 (Figure 5.2 and Figure 5.3).
During the worst drought years, annual rainfall has been about 600 mm or 30%
below the long-term mean annual rainfall of about 890 mm. Monthly rainfall has
varied even more. During the 20th century, monthly rainfall in rainy years has been
over three times the average. In dry years the monthly rainfall has been less than a
third of average, or there was no rainfall at all. It is also worth noting that shorter dry
spells lasting from 1 to 2 weeks (which do not necessarily show clearly in the monthly
rainfall data) during critical periods of the growing season can reduce crop yields
significantly.
5.2.4 Water Resources
The irrigation scheme lies in the Wami River Basin (Figure 5.1) on the Mkata Flood
Plain which is drained to the east by the Wami River and its tributaries, including the
Mkindo River (and its tributary, the Dizingwa River) and the Mgongola River, between
which the project area lies (Figure 3.1).
5.2.4.1 Mkindo River
The Mkindo River is the water source for the existing Mkindo I irrigation scheme and
also for the proposed Mgongola development. It flows eastward and empties into the
Diwale River before it joins the Wami River. It seasonally overflows its banks onto
the floodplain in which the project area lies. According to interviews with local
farmers of the area, annual flood water depth is approximately 0.3 m.
The annual historical mean flows for the Mkindo River as reported in the 1998
feasibility study are shown in Figure 5.4. Estimated daily mean flows are shown in
Figure 5.5 for the period November 2009 through to December 2010. The data in
Figure 5.5 seems to correlate strongly with that in Figure 5.4. Minimum monthly
flows for three dry-year scenarios (1 in 2 years, 1 in 5 years, and 1 in 10 years) are
shown in Table 5.2.
5.2.4.2 Dizingwi River
The Dizingwi River is a perennial tributary of the Mkindo River. Its water is always
stagnant and slow-moving in the Mkindo area. Currently, the Mkindo II scheme takes
water from the Dizingwi River because the siphon structure which should allow the
Mkindo main canal to cross the Dizingwi River has failed. No flow data exists for the
Dizingwi River, but it apparently has sufficient flow to serve Mkindo II, which has an
estimated irrigation water requirement of 0.1 m3/s.

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 Figure 5.4: Monthly Mean Flow Rate of Mkindo River
Source: JICA 1998, pg. D-III-4

Figure 5.5: Mkindo River Daily Flows (2009/2010)

18

16
Daily Flow (cumecs)
14

12

10

0
Nov2009 Dec2009 Jan2010 Feb2010 Mar2010 Apr2010 May2010 Jun2010 Jul2010 Aug2010 Sep2010 Oct2010 Nov2010 Dec2010

Table 5.2: Minimum Monthly Discharges of Mkindo River (m3/s)

Return
Period
(years) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
10 1.04 1.45 1.75 5.07 3.38 2.37 1.54 1.10 0.69 0.59 0.50 1.03
5 1.46 1.79 2.34 6.27 4.33 2.84 1.79 1.33 0.89 0.78 0.75 1.46
2 2.80 2.65 4.15 9.42 7.12 4.05 2.37 1.93 1.46 1.34 1.67 2.85
Source: JICA 1998

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5.2.4.3 Mgongola River
The Mgongola River is an intermittent river that runs along the southern boundary of
the proposed Mgongola scheme and flows from west to east. It flows only during the
rainy season, when it flows into the Diwale River downstream from the confluence of
the Mkindo and Diwale rivers. It habitually inundates the Mgongola project area in
the rainy season. According to interviews with local farmers of the area during
2011/2012, the flood depth along the river at the peak is 0.8 m to 1.0 m in the area
upstream of the proposed Mgongola scheme and 0.5 m in the area downstream of
the Mgongola scheme. The Mgongola River is the primary source of drinking water
for livestock from Kambala Village, 7 km south of the project area. No flow data
exists for the Mgongola River.
5.2.4.4 Water Demand and Water Rights on the Mkindo, Diwale and Wami
River
There are only two water rights on the Mkindo and Diwale rivers. The Wami-Ruvu
Basin Water Office (WRBWO) granted the Mkindo farmers’ cooperative a water right
in 2002 to abstract 0.624 m3/s from the Mkindo River with no restrictions on
abstractions during the dry-season flows (WRBWO 2015). The water used by the
Mkindo irrigation schemes is most likely less than their water right, as they have an
irrigation requirement of only 0.22 m3/s; however, there are no records of actual
water use by the cooperative.
The Mtibwa Sugar Estate also has a 1.5 m3/s water right to abstract water from the
Diwale River below the junction with the Mkindo River8. The USAID-funded report,
Profile of the Wami River Sub-basin (TCMP 2008, p9), states that the actual
maximum daily abstraction is 1.5 m3/s, falling to 0.5-0.75 m3/s in the rainy season9.
The Diwale River joins the main Wami River upstream of the Mtibwa EFA site.
The Dizungu Sugar Estate is located north of the project area on the banks of the
Mkindo River. It has approximately 300 ha of sugar under cultivation. It apparently
uses surface water from the Mkindo River for irrigation, but there is no record of it
being issued a water right or information on the size of its abstraction (if it indeed has
an abstraction).
There are currently no other major water users on the Mkindo and Diwale drainages.
Two small fish ponds are supplied water directly from the Mkindo main canal through
100-mm diameter pipes through the wall of the concrete lining. According to the
Mkindo water users group, water is abstracted at these points until there is
approximately 1-m depth of water in each fish pond at which point the pipes are
plugged with grass and the water is contained. Assuming that each pond has a plan
area of 10 m x 20 m, that seepage rates are low and peak evaporation is 6.7
mm/day, then the water abstraction can be considered negligible (<0.1 l/s). As of
July 2013 only one of these ponds was in operation. The owner had abandoned the
second pond but continued to use the remaining pond in a sub-optimal manner.
The Mkindo River flows into the Diwale River, which flows into the Wami River.
Population growth in the Wami Basin both upstream and downstream of the
confluence with the Diwale River has resulted in increased pressure being placed
upon the water resources of the basin. A number of abstractions have occurred
upstream of the confluence in recent years, some with and others without water

8 Water Right Registration Number 4501 of 1980 (WRBWO 2015).

9 The source of the water use information was the Mtibwa Sugar Factory’s irrigation engineer.

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rights. This has resulted in the depletion of flows throughout the Wami Basin, most
noticeably during the dry season when Wami River flows are at a minimum.
The list of all other permitted water users upstream and downstream of the
confluence of the Wami and Diwale rivers is presented in Table 5.3.

Table 5.3: Existing Permitted Water Users Upstream and Downstream of

the Confluence of the Wami and Diwale rivers

S/N Water Right Holder Q (l/s) Source

Upstream of the Confluence of the Wami and Diwale Rivers
1 Kilangali Seed Farm 1,140.00 Miyombo
2 Zombo Farm 1,140.00 Miyombo
3 Sumagro Ltd 7.25 Miyombo
4 Kilangali Farmers Group Scheme 300.00 Miyombo
5 Zombo Farmers Self help Group Scheme 28.30 Miyombo
6 National Agriculture Co. Ltd 0.53 Miyombo
7 Director of Veterinary Services 0.53 Miyombo
8 Magole Farm Irrigation Scheme 240.00 Wami
9 New Msowero Farm Irrigation Scheme 566.00 Wami
10 Rudewa Estate 11.55 Wami
11 Patel Farm 283.00 Tami
12 Abdallah Chana Farm 226.00 Tami
13 Mvumi Farmers Coo-p. Society 90.00 Kisangata
14 Mvumi Farmers Irrigation Scheme 586.00 Kisangata
15 Noble Agriculture Enterprises Ltd 60.00 Kisangata
16 Ilonga Agricultural Research Institute 300.00 Ilonga
17 Chanzuru Irrigation Scheme 130.00 Ilonga
18 Ilonga Cooperative Irrigation Scheme 100.00 Ilonga
19 Ilonga Research Institute 28.30 Ilonga
20 Rajab Meghji Visram 14.15 Ilonga
21 Rajab Meghji Visram 14.20 Ilonga
22 Alchadira Salama Children Centre Requested Wami
23 Dakawa Irrigation Scheme 5,000.00 Wami
24 Mtibwa Sugar Estate 1,500.00 Diwale
25 Mtibwa Sugar Estate 2,500.00 Wami
Mtibwa Sugar Estate (pending, in final
26 7,500.00 Wami
stages of approval)
Downstream of Confluence of the Wami and Diwale Rivers
27 SEKAB Bioenergy Tanzania Ltd 6,470 Wami
28 Sugar Development Cooperation 9,080.00 Wami

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5.2.4.5 Wami River Environmental Flow Assessment
The WRBWO is ultimately responsible for taking into account other users, present
and future, and for issuing and reviewing abstraction licenses. In 2007, the
WRBWO, in collaboration with the University of Dar es Salaam and Florida
International University, began an Environmental Flow Assessment (EFA) process
for the Wami River sub-Basin in order to better understand the flow needs of
ecosystems. The first round of the EFA for the Wami River was carried out in April-
December 2007 and reported in the Initial EFA Synthesis Report (Sarmett et al.
2008). The second round of investigations was completed in April and May 2011 and
reported in August 2013 (iWASH 2013a) to obtain wet season data. Phase II was
able to fill gaps in understanding that were identified in the 2008 report, update
analyses of the hydrologic record, and revisit the original environmental flow
recommendations. The wet season findings did not have a significant impact on the
initial flow recommendations.
The EFA method and the subsequent flow regime recommendations rely on bringing
the various experts and key stakeholders together to agree on the 'desired state' of
each section of the river. This is not just an exercise in simply assessing how much
water can be taken from the river at a particular point, and how much should be left –
it is also a series of political and managerial decisions on the balance between using
available water for productive/developmental purposes, versus maintaining the river’s
ecological systems at an acceptable standard.
Of the sites assessed in the EFA, the Mgongola irrigation scheme is located
upstream of and near to the Mtibwa site on the Wami River. An additional EFA
assessment site is located further downstream at Mandera (see Figure 5.6). The dry
year recommended average discharges (RAD) to maintain environmental flows10 in
the Wami River at Mtibwa and Mandera from the 2008 and 2013 assessments are
presented in Table 5.4.

10 iWASH 2013 defines environmental flow requirements to include ecological, geomorphological, and
human domestic needs.

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 Figure 5.6: Wami River Basin with EFA Sites
Source: iWASH 2013a

Table 5.4: Dry Year Recommended Average Discharges for the

Wami River at Mtibwa and Mandera EFA Sites
Recommended Average Discharge (m3/s)
Wami River at Wami River at Mandera
Month Mtibwa EFA Site EFA Site
March 3.0 5.6

April 5.0 21.7

May 5.0 21.7

June 5.0 15.5

July 4.1 9.2

Adapted from iWASH 2013, Tables 45 and 46

5.2.4.6 Water Quality

No continuous water quality monitoring has been done on any of the rivers in the
project area, including the Wami River. The EFA (iWASH 2013a) contains limited
water quality data collected for the Wami River Basin in April 2011 from the five EFA
monitoring sites, including the Mtibwa site just downstream from the confluence of
the Diwale and Wami rivers. Data from that site are highlighted in yellow in Table
5.5.

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 Table 5.5: Water Quality Data from EFA Sites

Source: iWASH 2013a

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The samples in Table 5.5 were taken during the rainy season when the Mgongola
area was being cultivated. The results indicate that there are no water quality
problems (elevated nutrients or salinity) in the Wami River downstream from the
project area.
5.2.5 Air and Noise
The project area is rural with few sources of air pollution or noise. No homes,
schools, medical facilities or other noise sensitive receivers are located in or near the
project area.

5.3 Biological Environment

5.3.1 Vegetation
As the entire project area is under cultivation in the rainy season, the vegetation is
that associated with cultivated fields. During the dry season grasses and forbs are
present in the fields. Some individual trees and small clumps of trees and shrubs are
scattered throughout the project area (see Figure 5.7).
Rice is the dominant species Oryza sativa associated with some weed species of
wild rice (Oryza punctata) and other grass species, including Leersia hexandr,
Echnochloa haploclada, E. colonum and Chloris gayana. Common herbs include
Ipomoea aquatica, Sphaeranthus senegalense, Spigelia anthelmia and Ammania
prieureana.
Most of the land surrounding the project area is also cultivated land, however some
woodlands and wooded grassland can be found in the hilly terrain northwest of
Mkindo Village. Riverine forests can be found on some stretches of the rivers in the
area, as well as some marshland.
Riverine forests are represented by patches of trees along the Mkindo River with
multilayer canopies reaching a height up to 20 m. Common tree species are: Afzelia
quanzensis, Parkia filicoidea, Breonardia salicina and Sorindeia madagascariensis
which are vulnerable timber tree species. Riverine forest vegetation type is located
at the intake to the existing irrigation system.
Marshland is a transitional zone between water and land normally being dominated with
sedges, rushes and grass species. In the project area this vegetation is found in very
small parches, primarily along the river banks. Common plants in marshland are sedge
species of Cyperus rotundus, C. immensus, C.distan, C rotundus, and Fimbrystylis
dichotoma.
No endangered or threatened species on the CITES list (Convention on International
Trade an Endangered Species of Wild Fauna and Flora) or the IUCN Red List of
Threatened Plants and Animals have been identified in the project area.

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 Figure 5.7: Google View of Vegetation in the Project Area
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5.3.2 Wildlife
Since the project will be implemented in the area that has been subjected to
recurrent agricultural activities alternated by livestock grazing during the dry season,
there was no justification of carrying out any substantial fauna survey in the project
area. However through literature review and opportunistic observation of fauna
around the project area and upstream in the Mkindo Forest Reserve, several species
of birds, mammals, amphibians and reptiles were identified as being present in or
near the project area. In total, 62 observations of fauna were made, 52 within the
Forest Reserve and 10 observations in the grassland and farmland surrounding the
reserve. The observations are tabulated in Annex B and summarized in Table 5.6.
One frog species was found to be endemic to the Eastern Arc Mountains (Callulina cf
kreffti) while one primate species (Galagoides zanzibaricus) is near-endemic to the
Eastern Arc Mountains and is also listed as Vulnerable to extinction by IUCN.

Table 5.6: Fauna Observed In and Near the Project Area

Number of Species Observed
Taxon
Mkindo FR Other Total
Bird 29 9 38
Mammal 13 1 14
Reptile 6 0 6
Amphibian 4 0 4
Total 52 10 62
Source: Bracebridge, 2006

According to local residents, wildlife inside the project area boundaries is dominated
by common species (e.g., baboons, wild pigs, and birds).
5.3.3 Protected Areas
The only protected area or nature reserve within the immediate vicinity of the project
area is the Mkindo Forest Reserve, which lies approximately 2 km northwest of
project area’s northern boundary. The boundary of the gazetted (in 2007) Wami-
Mbiki Wildlife Management Area lies 25-30 kilometers to the east of the project.
The Mkindo Forest Reserve Mkindo is categorized as a National Protection Forest
Reserves. As such it is reserved for the protection of watersheds, soil conservation
and wild plants. It covers an area of 5,244 ha in the Nguru South Mountains, part of
the Eastern Arc Mountains, and it is the source of the Mkindo River. The Forest
Reserve is under a low level of pressure from illegal cutting of poles and timber.
Other types of disturbance are grazing, charcoal burning, mining, cultivation and
paths. Of these, grazing is of greatest concern. Cattle are brought into the reserve
during the dry season. Grazing is also linked to forest fires.

5.4 Socio-Economic Environment

Data for the assessment of the current socio-economic environment was drawn from
published reports on the Mvomero District as well as observations and responses to
interviews with villagers in the project area.

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5.4.1 Administrative Boundaries
The Mgongola project area geographically belongs to Hembeti Ward which
comprises eight villages. Out of the eight villages only three, namely Mkindo,
Dihombo and Hembeti, will be direct beneficiaries of the project as they own plots in
the project area. The residents of the Kambala village, however, will be directly
impacted, as many of them are pastoralists and graze their cattle in the project area
during the dry season.
5.4.2 Demographic Characteristics
From the results of the Tanzania Population and Housing Census carried out in
2012, the population of the Hembeti Ward was 21,057, out of which 10, 311 were
males and 10,746 were females. The average household size for the ward was 4.3.
The JICA feasibility study (JICA 1998), drawing upon 1996 data, reported the
population in the three villages most impacted by the project (Mkindo, Dihombo and
Hembeti) as 8,470, with Mkindo Village having the largest population of 4,220. The
average household size in these villages in 1996 was 5.0. Fifty-three percent of the
population in the villages was under the age of 15.
A more recent study by the AgWater Solutions Project (Keraita et al. 2012) found that
rain-fed farmers in Mkindo were typically married with an a primary-level education
and an average household of 7.2 family members, as compared to 5.5 for irrigators.
For both groups the average number of household members who contribute to
farming activities is 3.
Kambala is another village potentially impacted by the project. It is located 16 km
south of the project area, but the residents of the village graze their cattle in the
project area during dry season. It has an estimated population of 2,800 (Mung’ong’o
2003). No information is available on how many of those individuals graze their
cattle in the Mgongola project area during the dry season.
An estimated 725 farmers are currently farming in the Mgongola project area.
Assuming an average household size of 7.2 (Keraita et al. 2012), this means that the
project could directly impact 5,220 individuals.
The situation of housing in the study area exhibits typical semi-urban and rural
setting. About 58% of houses in the villages are semi-permanent constructed by
poles and mud with galvanized sheets, while the remained 42% comprises of houses
made of cement bricks, with cement floor, plaster and roofed with iron sheets.
5.4.3 Land Use
The greater part of the Mvomero district is cultivated and the remaining parts are
protected areas (forests, game reserves etc.). Some areas in the district are left
uncultivated because they are on very steep slopes and some are constantly flooded.
The Department of Agriculture of the Mvomero District Council estimated in 2011 that
the Mgongola area had 2,720 ha suitable for irrigation. Of that, only 110 ha in the
Mkindo schemes are being irrigated.
Livestock grazing is also practiced in the district in wooded and open grasslands, as
well as on cultivated land during the dry season. Land is more intensively used in the
low lands and Mngeta slopes.
As can be seen in Figure 5.8, the entire area inside the project boundaries is
currently used for rain-fed rice production. All of the area is cultivated, with only a
scattering of trees (often only individual trees) on the borders of fields (Figure 5.7).

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During the dry season, much of the area is used for grazing cattle, owned by the
farmers themselves, or by pastoralists from Kambala village. The Kambala cattle are
grazed on communal village land from January to June, but a majority of the animals
are moved to other areas, such as the project area, from July to December. There is
an unwritten “agreement” between livestock keepers and farmers that once the
farmers have harvested their crops, livestock keepers gain access to grazing in the
farms. In recent years, however, that informal arrangement has deteriorated,
causing some conflicts between farmers and cattle herders. Some residents
indicated that there was no charge for the use of the land, but others indicated that
pastoralists paid farmers for the use of the land.
5.4.4 Land Ownership and Tenure
The tenure system in the study area is generally based on traditional inheritance,
land allocation by village council, land purchasing, and land borrowing or renting.
The most common tenure regime in the scheme is the one based on “customary
tenure” where land rights are transferred according to an ancestral tenure of land
and/or the traditional inheritance accepted by the village council. The 1998 JICA
study team estimated that the average landholding size per farm household for
Mgongola is 1.62 ha (rain-fed plus irrigated areas). The average plot size in the
project area is 0.9 ha/household.
The AgWater Solutions Project study (Keraita et al. 2012) found average plot sizes in
the Mkindo rain-fed area to be 1.1 ha. It also found that most of the farmers in the
Mkindo irrigation schemes also had rain-fed plots outside of the schemes. Many of
these may be in the Mgongola project area, as it abuts to the Mkindo schemes.

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 Figure 5.8: Land Use in the Project Area

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5.4.5 Economic Activities
Household interviews indicated that agriculture is the primary occupation of 99% of
the households in the villages near the project area. These households reported that
97% of their income is from agricultural production. Even for the households with
other sources of income agriculture contributed more than half of their income and
expenditure.
The residents of Mkindo, Dihombo and Hembeti villages are generally farmers. The
residents of Kambala village are generally pastoralists.
Most farmers grow rice for subsistence as well as for sale in the market. On
average, the rain-fed farmers in the region consume 60% of the rice they grow. In
addition to rice, rain-fed farmers may grow food crops such as groundnuts, beans,
cocoyam, cassava, vegetables and maize. All these are produced in the wetland
areas along the rivers. They may also have small gardens near their houses and
fruit trees scattered around the villages.
Rice is the staple food crop. Because of topographic differences, which create
different crop suitability in the watershed, most farmers have some rice fields in the
lower lying areas and some fields for maize in the higher lying areas. This is a risk
mitigating strategy. When there is too much rain in one period and little drainage,
rice will be affected negatively because the water level will be too high but the maize
crop on the higher lying land will do better. When it is too dry the water accumulates
in the lower lying areas making a harvest of rice possible, but making maize harvest
lower (de Bruin et al. 2012).
The rains in 2008 were very low and rice was generally not harvested by the farmers
in the project area (de Bruin et al. 2012).
Part of the livelihood strategy of rain-fed farmers is livestock keeping. All of them
keep a small number of animals. The animals graze along the roads and on the
fringes of the forest. Goats graze along the roads close to the villages. Dairy cattle
are kept next to the house. During the dry season they may graze in the fallow rice
fields.
As mentioned in Subsection 5.4.3, rain-fed farmers may also lease their rice fields to
those mainly dependent on keeping livestock. The land is let for 3 to 4 months
during the dry season and will again be used for crops during the wet season.
However, some respondents indicated that the herders did not pay the farmers for
the use of their land. As a result, there has been conflict between farmers and
herders.
Predominantly crop production in the area is done by family labor, although
seasonally hired laborers may be used for land preparation, transplanting and
harvesting. Women, as well as men, participate in farming. Women are involved in
all aspects of farming except for the heavy work during harvesting and the selling of
products. These activities are still largely carried out by men.
There is no industry in any of the villages, although there are some grain storage
facilities and rice and maize milling facilities. Other off-farm income sources include
micro- and small-enterprises; petty business; small-scale workshops; limited salaried
positions; raising poultry, pigs and/or goats for sale; and hiring out as day labors to
third parties.
Micro- and small-scale enterprises includes retail shops, small restaurants, petty
trade and selling of local brew. Several retail shops situated in village centers stock
a wide range of goods including foodstuffs, household utensils, school supplies,
textiles and spare parts for bicycles. Construction materials such as corrugated iron
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sheets and cement are also stocked by some shops in the area. Shops adopt
various techniques to keep the operation costs low. For example, shops are often
located in one of the rooms within a home, and usually attended and managed by
members of the household. Procurement of goods to be sold in shops is generally
done in bulk to optimize transport costs, but sometimes household members procure
and transport small amounts of goods using motorcycles or public transport.
There are few small restaurants and numerous food vendors in the study area. The
restaurants serve soft drinks, tea, snacks and meals, basically to external visitors and
limited number of village residents. During the peak of the agricultural season, the
restaurant operators withdraw temporarily from their restaurant activities to attend
agriculture. Food vending, snacks and evening coffee/tea selling are also very much
affected during this time because the desirable customers migrate to temporary
camps in the farm plots. Selling of beer and local brew, locally known as komoni, is
common in village centers where people meet in the evening for refreshment.
Petty trade includes selling a range of products in small quantities in homes, at the
local market, or along the streets. The food products sold include maize and
cassava flour, vegetables, dry cassava, fresh and dried fish, fruits, and bananas.
Other products sold by petty traders include household utensils and textiles, and
clothing, mainly second hand clothes.
Small-scale workshops refer to tailoring, carpentry, bicycle repair and blacksmiths.
Tailors are mostly called upon to mend clothing. According to the respondents,
tailoring is not a lucrative business and the operators are busy only when pupils are
beginning a new school year and when religious ceremonies are held, especially if
they fall in the crop-marketing season.
Carpentry workshops are mainly involved in production of furniture (beds, chairs,
drawers, tables) as well as doors and windows. Furniture most often made on order
from within the villages or in nearby villages. Most of the timbers used by the
carpenters in the village are obtained within the district.
Blacksmith deal with repairing and welding of tools such as metal kitchen appliances,
hoes, knives, and machetes brought to them by owners. In some cases they use
scrap metal to manufacture tools for sale.
Bicycle repairing is a lucrative income earning activity. According to the obtained
information almost all the people who own bicycles have basic knowledge in repair,
but there about five artisans repairing and selling minor bicycle parts. Major bicycle
parts are commonly available in retail shops in the village and sometimes are
purchased from Morogoro town.
Prominent occupations recognized for salaried employment are found in the sectors
of education, home affairs and local government. These sectors employ teachers,
police, village executive officers, ward executive officers and medical personnel. The
study noted that most of the employees originate from within Mvomero district.
5.4.6 Income and Expenditure
The average income in Mvomero District is estimated at Tshs. 450,000 (2010)
income per capita. This includes the value of cash and in-kind production and
transfer payments (District Profile, 2011).
During the interviews with residents in the project area, they were reluctant to reveal
information on incomes to strangers. The majority of villagers who were willing to
talk about income showed strong uncertainty in estimating their incomes and
expenditure, even those referring to short duration of time such as a day or two.
They did indicate, however, that incomes and expenditure vary strongly with
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 5-19
seasons, with harvest season being the greatest time of both income and
expenditures.
The economy in the project area is basically subsistent, with the households failing to
demarcate between amounts of food that come from their own production and that
from the market. Several transactions and transfers, including remittances from
relatives living in other villages or cities, are in-kind rather than cash. Villages are not
able to determine precisely the monetary value of such incomes and expenses.
5.4.7 Water, Sanitation and Solid Waste Disposal
All of the villages in the project area take domestic water from the rivers near the
villages (Mkindo Village from Mkindo River, Dihombo Village from Dizingwa River,
and Hembeti Village from Mgongola River). None of the villages have village-wide
piped water. None of the villages have village sewer systems.
The most commonly used excreta facilities in the project area are pit latrines. More
than 80% of pit latrines in the study area are of poor quality.
There are no sanitary facilities in the fields where people spend more than 5 months
farming, weeding and harvesting. During farming activities people defecate outdoors
in their fields or nearby bushes.
There is no sanitary landfill in or near the project area for disposing of solid waste.
None of the villages have solid waste collection systems. Some individuals dispose
of solid waste in pits (15%), but the majority (82%) use plots/farms as a dumping site.
5.4.8 Health
As summarized by the 1998 JICA study, health service facilities in the Mgongola area
fall short of WHO-recommended minimum requirements. In the district there is one
hospital (Bwagala in Turiani) and a few health centers and dispensaries. Mkindo and
Hembeti villages have dispensaries, but Dihombo village does not.
Malaria has the highest incidence of disease in the district, accounting for 50% of all
reported disease cases. Another 10% of reported disease cases are associated with
other water-borne diseases, including intestinal diseases and diarrhoea diseases.
JICA 1998 found that the rate for schistosomiasis (bilharzia) was 2.5%. Acute
respiratory infections and pneumonia account for another 26% of total reported
disease cases.
5.4.9 Energy
There are different kinds of energy, which are used by people of Mvomero district.
These include electricity, fuel wood, kerosene, solar and bio-gas. Fuel wood and
charcoal is the dominant energy source for the majority of people in Mvomero district
and the study area in particular for household cooking and other domestic purposes.
Electrical power is also available to three of the villages (Hembeti, Mkindo and
Dihombo) from the national grid through the national service provider, the Tanzania
Electric Supply Company, although very few people have managed to connect. JICA
1998 reported that only 20 houses in Mkindo, 10 in Hembeti and 3 in Dihombo had
electrical connections. This situation has undoubtedly improved, but still electrical
power is the exception rather than the rule in the project area.
Kambala has no access to electrical power.
5.4.10 Transport and Communication
The three villages (Hembeti, Mkindo and Dihombo) in the project area are connected
via a main road (B-127) to the trunk road from Morogoro to Dodoma, which is the
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 5-20
main means of transport in and out of the district. The village of Kambala is served
only by a road that is accessible only during the dry season. In the project area there
are farm access roads which facilitate transportation of farming inputs and outputs to
and from the trunk road. However during rainy seasons these farm access roads are
not passable.
Telecommunication networks are available in the project area. Many companies are
operating in the area and in the district in general, including Tanzania Telephone &
Communication Limited, Vodacom, Airtel, Tigo, and Zantel. Radio and television are
also available, including Radio Abood, Tanzania Broadcasting Corporation, Radio
One, Independent Television of Tanzania and Channel 10.
5.4.11 Vulnerable Groups
Women in Mvomero District have the primary responsibility for agriculture, small
business, and household activities. Despite these responsibilities, their participation
in decision-making is limited, even though they occupy about 30% of seats in the
village councils. The presence of women in leadership roles in the villages is limited
due to large families without financial resources coupled with some passive
traditional cultural and religious beliefs discriminating against women, giving them
limited access to household money and other resources, even though they are the
primary providers.
Married women in the village surveyed lack access to and control over available
resources. For example, although women are responsible for agricultural production,
men are generally the legal owners of the land and can block women from carrying
out their work. Livestock is another example. Men are responsible for all decisions
regarding animals, including when to buy and sell the livestock. About 80% of
women interviewed reported men as the sole decision-maker in financial matters.
The remaining reported both husband and wife make decisions together.
5.4.12 Capacity of the WUA
The WUA that will manage the new irrigation scheme has yet to become operational,
but there is a WUA in existence that manages the Mkindo I and Mkindo II irrigation
schemes. That WUA will disband once the new irrigation system is operational and
its members will become members of the new WUA that will manage Mgongola
irrigation scheme as well as the Mkindo irrigation schemes. So although the new
WUA is not operational, it will have up to 100 members with experience in managing
a WUA.
The existing Mkindo WUA was organized in 1984 by the farmers in Mkindo I as the
Mkindo Farmers Irrigation Agricultural Marketing Primary Cooperative Society Ltd. In
1986, the farmers in Mkindo II joined the WUA. By 1997, it had 97 members. In
1997 the WUA registered with the Ministry of Agriculture and Cooperatives (the
predecessor of the MAFC). The WUA has written and approved by-laws and is
managed by a 10-member Executive Committee composed of the Chairman, Vice-
Chairman, Secretary, Treasurer and six at-large members, elected by the
membership. The WUA collects annual fees from its members. (JICA 1998)
Two times per year, about 1.5 months before planting, the WUA holds a general
meeting for all of its members, chaired by the village agricultural extension officer. At
the meeting decisions are made concerning planting schedule, irrigation
commencement and termination dates, and maintenance activities. The
maintenance activities are undertaken by the members as communal works, usually
for a period of one week each. The WUA uses a penalty structure, whereby
members that do not participate in the maintenance communal works are fined.
(JICA 1998)
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The Mkindo Farmers Training Centre is located in Mkindo village. Here farmers can
receive training on new farming techniques. The Centre has provided training to
farmers on new and more efficient techniques for rice production. For some this has
increased their production, for others there is still more to learn. The government has
extension officers to disseminate knowledge and advice throughout the rural areas.
However the extension officers lack the means of travelling through the area. This
makes it difficult for farmers to get the advice they need when they need it. There
are many extension officers but the lack of transport facilities means extension is not
carried out to its full potential. (de Bruin et al. 2012)

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6 ENVIRONMENTAL CONSEQUENCES
As required by 22 CFR 216.6, this section provides the analytic basis for the
comparison of consequences presented in Section 4.9 of this EA. It describes the
environmental and social impacts of the Proposed Action and its alternatives,
including the No Action alternative.

6.1 Results of Scoping

As stated in Section 2 of this EA, IRRIP1 conducted scoping for this activity to
comply with USAID’s requirements and the GoT’s environmental impact assessment
regulations. Relevant sections of the Scoping Statement, particularly regarding the
stakeholder consultation process and issue identification, are attached to this EA as
Annex C. The Scoping Statement identified “potentially significant impacts” as well
as “non-significant issues that should have mitigation measures in the EA.” These
are presented in Table 6.1, with some modifications representing knowledge gained
during preparation of the EA. The assessment of environmental consequences
focuses on these potentially significant impacts.

6.2 Impacts Common to All Irrigation Alternatives

All of the impacts associated with the Proposed Action and the other irrigation
alternatives are the same. These impacts are identified and discussed in this
section. Some of these impacts may have a difference in magnitude depending on
which alternative is selected. Where there is a difference in magnitude, that
difference is discussed for each individual alternative at the end of each of the
following sub-sections.
6.2.1 Impacts During Mobilization and Construction
6.2.1.1 Positive Impacts
Opportunities for Temporary Employment
The construction works will generate employment for the 20-month construction
period. It is envisaged that some of the rehabilitation work will use labor-intensive
methods and there should be employment opportunities for local people particularly
during the months when the irrigation system is not operating.
The project will create job opportunities for both unskilled and skilled cadres
including:
 Supervising engineering team;
 Builders or contractor’s staff (managerial, skilled and unskilled labor force);
 Suppliers of plant, machinery, materials, and essential services; and
 Construction monitoring personnel from various government agencies.

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-1
 Table 6.1: Potentially Significant Impacts Identified in the Scoping
Statement
Non-Significant Issues that Should Have
Potentially Significant Impact
Mitigation Measures in the EA
During Mobilization and Construction (Irrigation Alternatives)

Positive Impacts: Positive Impacts:

 Opportunities for temporary employment  None
(Irrigation Alternatives)
Negative Impacts:
Negative Impacts:  Soil erosion
 Displacement of economic activities  Soil pollution
(Irrigation Alternatives)  Loss of top soil
 Disturbance of graves (Irrigation  Water contamination
Alternatives)  Solid waste generation
 Dust and air pollution
 Noise pollution
 Effects on aquatic species
 Worker/community health and safety
 Change of community lifestyle
During Operation

Positive Impacts: Positive Impacts:

 Reliable supply of irrigation water  None
(Irrigation Alternatives)
 Increased rice production Negative Impacts:
 Opportunities for employment  None
 Improvement of Market Outlets (Irrigation
Alternatives)
 Reduced Flooding (Irrigation Alternatives)
 Reduced Water logging (Irrigation
Alternatives)

Negative Impacts:
 Soil salinity (Sprinkler Irrigation)
 Effects of pesticide and fertilizer use
 Water contamination
 Water quantity impacts on downstream
users and ecosystems (Irrigation
Alternatives)
 Effects on aquatic species
 Land use conflict – cultivation/grazing
 Scheme management capacity (Irrigation
Alternatives)
 WRBWO capacity to control water
abstractions (Irrigation Alternatives)
 Change of community lifestyle

6.2.1.2 Negative Impacts

Physical Environment
Soil Erosion
Earthworks will contribute to a large amount of soil movement around the
development site as the office, canals, roads, flood barriers, temporary material
storage areas and agricultural plots are constructed. Soils from disturbed surfaces

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are likely to be washed away during the rainy season and also in dry conditions
through wind erosion. If cut and fill sites are not protected, loose soils can equally be
washed away into the canals and later into the Mkindo, Mgongola and Dizingwa
rivers. The risk of soil erosion is considered high, particularly during high and intense
rainfall, given the proximity of the rivers, the scale of the earthworks and the
characteristics of the overburden in the area which is easily erodible.
Soil Pollution
Vehicles and equipment used during construction may impact the soil with oil and
fuel spills. Trucks hauling construction materials such as aggregates, sand and
gravel and equipment being move to and from a work site may pass through
agricultural fields and impact agricultural soil with oil and fuel spills. In addition,
areas where fuels, lubricants and chemicals are stored or where vehicles and
equipment are fueled or serviced can be sources of hazardous substance releases to
the soil. Improper disposal of concrete wastes resulting from on-site concrete
batching or cleaning of ready-mix concrete vehicles can also contaminate soil.
Loss of Top Soil
Construction of irrigation and drainage structures will require fill material. As
mentioned in Sections 4.1.1.1 and 4.1.2.5, fill material will generally be taken from
drain excavations or off-site locations. During the construction of secondary and
tertiary canals, however, some fill material may be taken from adjacent fields,
particularly if the field is in need of land levelling. In these cases, the potential exists
for the destruction of top soil.
Water Contamination
If erosion occurs and/or soil is polluted, as discussed above, it is possible that the
Dizingwa, Mkindo and Mgongola rivers may be impacted with sediment,
leaked/spilled lubricants, fuels and hazardous substances. Other sources of
potential water pollution are:
 Washing vehicles or equipment in or nearby the river;
 Improper disposal of concrete wastes resulting from on-site concrete
batching or cleaning of ready-mix concrete vehicles;
 Surface run-off from on-site stockpiled sand and gravel; and
 Inadequate disposal of solid wastes and wastewater generated during
construction from workers.
Solid Waste Generation
Solid waste will be generated from site vegetation clearance and during construction.
The vegetation and other rubbish that will be cleared from the site will lead to the
generation of large volumes of waste that require proper disposal.
Various wastes generated during construction will need to be managed and disposed
of properly. These will include solid waste from packaging materials, wood and steel
crates, cardboard, wrapping materials, boxes, sacks, drums, cans and chemical
containers and any other unused materials. Workers will also generate domestic
solid waste.
Dust and Air Pollution
The vehicles and machines used in the construction of civil works will produce
exhaust smoke, fumes and dust that may be unpleasant to the surrounding
communities.
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-3
Noise Pollution
The vehicles and machines used in the civil works will produce noise that may be
unpleasant to communities who live near the project area.
Biological Environment
Effects on Aquatic Species
As for the aquatic organisms, the only animals that could be impacted by the project
activities include fish and amphibians due to siltation of the rivers (which could clog
their breathing apparatus) and pollution from leaked/spilled lubricants, fuels and
hazardous substances. Vegetative removal and soil excavation could lead to
siltation of the rivers during the rainy season.
Socio-Economic Environment
Displacement of Economic Activities
Construction activities can disrupt current farming practices the project area.
Building the main canal and flood control structures will disrupt the flood flows into
the area, on which the farmers rely for creating ponding for their rice fields.
Disturbance of Graves
During scoping some participants expressed concerns that graves in the project area
could be disturbed during construction. IRRIP1 determined that there were no
marked graves in the project area, but there may be unmarked graves that could be
encountered during construction activities.
Worker/Community Health and Safety Impacts
Workers at the site will be exposed to several safety hazards, including open
trenches, openly stored or moving construction materials, and moving construction
equipment.
Workers’ camps may be a source of social unrest and environmental problems such
as transmission and spread of diseases (e.g. HIV/AIDs, sexually transmitted
infections (STIs) or sexually transmitted diseases (STDs)) to the resident community
by the project personnel and vice versa.
Also, construction sites can be dangerous places for the safety of residents of nearby
communities. These residents may not be aware of the hazards and they may
simply be interested in observing the equipment and activities. Children are often
eager to see construction equipment at work. Such children’s curiosity may lead to
safety hazards ranging from minor to major injuries such as bruises and fractures.
Change of Community Lifestyle
The construction of the Mgongola irrigation scheme will have an impact on the day-
to-day lives of the Mkindo and Dihombo villages. An influx of workers to the area will
bring increased economic activity, with and associated positive impact. But the
workers may also bring with them behaviors which disrupt the community and puts
them and the community at increased risk for HIV/AIDS.
6.2.2 Impacts During Operation
6.2.2.1 Positive Impacts
Reliable Supply of Water
Construction of the Mgongola irrigation scheme will help to ensure a reliable supply
of water to irrigate the 589-ha area. Currently the farmers are reliant upon flood

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-4
water and rain to produce their crops. The timing and quantity of water delivered via
flooding and rainfall is unpredictable. Climate change is projected to increase the
unreliability of these sources of water by increasing uncertainty of the onset of rainfall
and its regularity (iWASH 2013b). Thus farmers will be facing increasing uncertainty
regarding water availability.
The irrigation works will include provision for flow measurement in the main and
secondary canals. It will also include controls (e.g., gates) in the canal system.
These will enable the discharge into the system to be regulated and the water
delivered to each secondary canal to be monitored and controlled thus improving
overall conveyance effectiveness and water use efficiency.
Increased Rice Production
The literature and experience in Africa and around the world has shown that irrigated
paddy rice produces yields 2 to 3 times higher than rain-fed paddy rice production
(Nguyen 2010, MoFA 2009, and Eklou et al. 2008). This is due to the ability to
manage water, a critical factor in rice production.
In the Mgongola area irrigated paddy rice is currently producing 2-3 times the mt/ha
per harvest as rain-fed paddy rice production (de Bruin et al. 2012, Keraita et al.
2012). As noted in Section 3.4.3, current rain-fed paddy rice production in the
project area is reported to be 1.6 to 3.0 mt/ha (JICA 1998, Keraita et al. 2012). In
comparison, the same studies reported rice production on the nearby Mkindo
irrigation schemes to be from 3.8 to 6.0 mt/ha during the rainy season.
At the time of the JICA study, 22% of the farmers in the irrigated area were
participating in a Food and Agriculture Organization (FAO) program that provided
improved seed and fertilizer inputs. The farmers in the FAO program realized an
average yield 5.2 mt/ha (JICA 1998, Table 1.3.2). The other farmers in the irrigated
schemes, using seed and input practices similar to those used by the rain-fed
farmers, realized an average yield of 3.4 mt/ha.
Keraita et al. (2012) found that irrigation doubled the yield per hectare. The JICA
study also found that farmers in the Mkindo irrigation schemes using traditional seed
and inputs had slightly more than double the yield of farmers in the project area
growing rain-fed paddy rice with traditional seed and inputs (3.4 vs. 1.6 mt/ha). So it
is reasonable to assume that irrigation alone can be expected to double rice yields.
This is due to improved ability to manage water inputs via irrigation.
If in addition to irrigation farmers adopt improved practices such as planting improved
seed and using fertilizer and herbicides (when necessary), their yields could increase
even more. The JICA study found that adopting such practices could improve yield
by an additional 53% (from 3.4 to 5.2 mt/ha).
For the comparative purposes, this EA has chosen to use the JICA rain-fed yield of
1.6 mt/ha as a baseline, No Action yield. This is based on the fact that the data for
Keraita (2012) was collected in 2009 and 2010, years in which yields in the area
were generally higher than usual. Yield for irrigation alone is assumed to double to
3.2 mt/ha and the yield from irrigation plus improved cultivation practices is assume
to increase by another 53% to 4.9 mt/ha.
Proponents of SRI have claimed 2-3 time increases in yield (SRI-RICE 2014).
Several academic studies, however, have indicated that these increases are not
significantly different from those that may be gained from paddy rice irrigation using
conventional best management practices (Bouman et al. 2007, McDonald et al.
2006). For the purposes of comparison, therefore, this EA has assumed that rice

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-5
production with SRI would be equivalent to that for irrigation with improved cultivation
practices, 4.9 mt/ha.
In summary, the potential increases in rice production associated with the irrigation
alternatives are as follows:
 Proposed Action, Piped Canal and Sprinkler Irrigation
o Irrigation alone: 3.2 mt/ha
o Irrigation and Improved Cultivation: 4.9 mt/ha
 SRI: 4.9 mt/ha
Increased rice production will lead to increased income for the farmers. Keraita
(2012) found that average income from farming in households that farmed in the
Mkindo irrigation schemes was $3.62 per day, as compared to $1.61 per day for
households that only practiced rain-fed paddy rice farming. Similar results have been
seen in other areas of Tanzania (Keraita 2012).
Opportunities for Employment
Long-term jobs will be created by the project in the form of employment at the WUA
and potentially employment of wage laborers. The WUA will have full-time paid
positions for a manager and possibly technical personnel. Doubling or even tripling
rice production in the irrigated area may create opportunities for wage labor during
cultivation and harvest. Generally such increased labor needs will be provided by
family members, but in peak periods at least some farmers may hire wage laborers.
The income from these employment opportunities will multiply through the villages as
the new wage earners spend their wages.
With increased production and employment opportunities, the standard of living in the
surrounding villages will improve and with improving social services, more people will
be attracted to stay in the village, especially youth. As such, construction of the
Mgongola irrigation scheme will complement the government’s efforts to improve the
standard of living, poverty alleviation and food security at household level. The
increase in income will lead to construction of improved houses with good sanitary
services which may reduce water-borne diseases.
Through observation during site visits in the communities, it was apparent that rice
farming has a positive development in house construction. Many people with poor
houses are either renovating or constructing new and modern houses. Some of
them revealed that after harvest, different economic activities including petty trading,
building houses, and buying motorcycles are carried out in the village
Improvement of Market Outlets
Improvement of farm access roads so that they will be passable in the rainy season
will allow farmers to more easily transport their harvest from the field to the market
and deliver inputs to the fields (seed, workers and equipment).
Reduced Flooding
Flooding was identified in the Scoping Statement as a significant negative impact of
the current situation. Although flood water is necessary for rain-fed paddy rice
production, too much flooding or flooding coming at the wrong time in the growing
cycle can harm or destroy a crop. The perimeter flood protection embankment will
eliminate flooding of fields during flood events, thus avoiding the negative impacts of
flooding.

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-6
Reduced Water Logging
Currently many fields in the project area are unlevelled and have no or insufficient
drains. This has resulted in water logging in some places in the project area, causing
reductions in crop yields. The project will build secondary drains and train the
farmers in construction of tertiary drains serving their plots. In addition, farmers
participating in the project will receive training on field levelling. As farmers practice
what they learn in these training sessions, they will improve overall drainage from
their plots and reduce or eliminate places in their fields that have poor drainage. This
will reduce or eliminate the current water logging problems.
6.2.2.2 Negative Impacts
Physical Environment
Soil Salinity
Soil salinity was identified in the Scoping Statement as a potentially significant impact
of the project. Upon further evaluation, however, increased soil salinity will not be an
impact of Proposed Action and all of the flood irrigation alternatives. Generally paddy
rice irrigation does not tend to create soil salinity, as sufficient water is applied to
wash salts below the root zone. The most common practice for addressing soil
salinity in irrigated fields is to leach accumulated salts below the root zone by
applying excess water. In paddy rice production, excess water is regularly applied as
part of the irrigation regime to meet the needs of the plants and control weed growth.
Even with SRI methods, there are extended periods when water is ponded on the
field, thus providing for leaching of any salts below the root zone. So accumulations
of salts in the soil will not be an impact.
With the Sprinkler Irrigation alternative, however, if farmers adopt sprinkling they
could encounter salinity problems overtime. This will be due to the fact that they will
no longer be applying water in quantities that will move the salts below the root zone,
allowing salts in the irrigation water to become concentrated in the root zone. This
could, however, take a considerable time to develop, as the irrigation water from the
Mkindo River is not particularly high in salts.
Effects of Pesticides and Fertilizer Use and Water Contamination
The construction of the Mgongola irrigation scheme, to be conducted by IRRIP1, will
not involve the procurement, promotion or use of pesticides. Currently the Mgongola
farmers do not use pesticides and fertilizers in their fields; however, they may choose
to do so in the future to increase agricultural production. Such practices are common
on the nearby Mkindo I and II irrigated areas. This could increase the use of
pesticides and fertilizers, which may lead to:
 Increased nutrients such as nitrogen and phosphorus, entering the rivers;
and
 Increased exposure by humans and the environment to toxic pesticides.
Nutrient increase in the rivers can damage the ecosystems. Nitrates and phosphates
may stimulate rapid growth of aquatic vegetation and algae blooms. Rapid growth of
aquatic vegetation may deplete oxygen and result in the death of fish and other
aquatic life. Fortunately, there is no evidence of rapid growth of aquatic vegetation or
fish kills downstream from the project area. But, neither is there any water quality
monitoring data from the same area, nor a systematic program for collecting that data
in the future, so it is difficult to fully assess this impact.
IRRIP1 does not have a Pesticide Evaluation Report and Safer Use Action Plan
(PERSUAP) as it does not work directly with farmers on farming practices. NAFAKA,
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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-7
however, does have a PERSUAP. Any work with the WUA farmers on improving
farming practices under the FTF program will be carried out by NAFAKA, under the
conditions of its PERSUAP.
The only pesticides reportedly used in the area are 2,4-D to kill weeds, and Selecron
(profenofos) and Karate (lambdacyhalothrinto) to combat insect pests. 2,4-D is in the
list of herbicides that are Accepted/Approved by the NAFAKA PERSUAP.
Profenofos and lambdacyhalothrinto are not on the list. Lambdacyhalothrinto was
specifically evaluated and excluded from the Accepted/Approved list. Profenofos
was not evaluated.
If farmers adopt sprinkling under the Sprinkler Irrigation alternative the amount of
water draining off the fields would be reduced or eliminated, thus reducing or
removing the pathway for these contaminants to flow into the Mgongola River. Thus,
the potential for water contamination from pesticides and fertilizer use will be less for
the Sprinkler Irrigation alternative than for the other irrigation alternatives.
SRI promotes the use of organic fertilizers and hand weeding. This could reduce the
amount of herbicides used by farmers. As organic fertilizer tends to have lower
concentrations of nitrogen and phosphorus, the adoption of SRI could also reduce
the amount of nitrogen and phosphorus available to runoff from the fields. Thus, the
potential for water contamination from pesticides and fertilizer use will be less for the
SRI alternative than for the other flood irrigation alternatives.
Water Quantity Impacts on Downstream Users and Ecosystems
The most significant potential negative impact of the project is its impacts on
environmental flows in the Wami River downstream of the project area. To
understand the potential impacts of the Proposed Action and its alternatives on
environmental flow, IRRIP1 assessed the flow requirements of the project in light of
the results of the EFA for the Wami River (Sarmett et al. 2008 and iWASH 2013a,
collectively referred to as the EFA). The IRRIP1 assessment of the Mgongola
irrigation scheme’s relationship with the EFA is included as Annex D. The area for
the analysis is hydrologically bounded by the Dakawa gauge (1G1) upstream and the
Mtibwa EFA site (see Figure 5.6) downstream.
In order to fully assess whether the irrigation scheme would reduce flows to below
the recommended EFA flows, IRRIP analyzed the impact of the project abstractions
on the recommended average discharge (RAD) values at the Mtibwa EFA site (see
Figure 5.6). The analysis was conducted using monthly data for the 5 months in the
rainy season when water is withdrawn for irrigation (mid-March through July). The
data was further restricted to the 1-in-5 low flow years, rather than average flows. So
4 years out of every 5 years the flows would be expected to be greater than those
used in the analysis.
To assess the impact of the abstraction for the Mgongola irrigation scheme on the
Mtibwa EFA site a number of factors need to be considered, including:
 Flow on the main Wami River at the Dakawa gauging station (1G1) (see
Figure 5.1);
 Flow on the Diwale River captured predominantly by gauges 1GB1A on
the Diwale River and 1GB2 on the Mkindo River, a tributary of the Diwale
River (see Figure 5.1);
 Abstraction rates for the Dakawa irrigation scheme;
 Abstraction rates for the existing Mkindo irrigation scheme;

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-8
  Abstraction rates for the proposed Mgongola irrigation scheme;
 Abstraction rates for the Mtibwa Sugar Estate;
 Abstraction rates for the Dizungu Sugar Estate; and
 RAD values for the Mtibwa EFA site.
Figure 6.1 shows the schematic location and relationship of these factors. An input-
output methodology was used to analyze the data where the inputs were the flows at
the gauging stations and the outputs were the abstractions. The flows minus the
abstractions can then be compared to the RAD at the Mtibwa EFA site to determine
their impact.
Flows
Flow data on the Wami River is available for several years from the Dakawa gauge
(1G1). Sufficient flow data is available to calculate the statistical 1- in 5-year low
flows at the Dakawa gauge (CDM Smith 2013, Annex F).
The Diwale River flows into the Wami River between the Dakawa gauge and the
Mtibwa EFA site as do several small drainages from the south of the Wami River.
The Mkindo and Divue rivers are both perennial and flow into the Diwale River. The
Mkindo River is the major tributary of the Diwale River. The Mkindo River has two
tributaries that flow into the river below the Mkindo gauge, the perennial Dizingwi
River and the seasonal Mgongola River.
There are no gauges on Divue, Dizingwi and Mgongola rivers or any of the small
drainages that flow into the Wami River from the south between the Dakawa gauge
and the Mtibwa EFA site, so their flows are not captured in the following analysis.
Flow data on the Diwale River (1GB1A) is available for six years from 1965 to 1970.
Six years is not sufficient for detailed statistical analysis of flow data. Therefore, to
adopt a conservative approach, the lowest average flow during each half-month
period was calculated and the lowest average for the six years of data was extracted
from the record and used in this analysis.
For the Mkindo River (1GB2) flow data is available for six years: 1965 to 1969 and
2009/2010. A similar approach to that used for the Diwale River was applied for the
Mkindo River to estimate a dry year flow for each half month period during the
abstraction period.
Abstractions
The Mtibwa Sugar Estate, Dakawa irrigation scheme, Mkindo irrigation scheme and
Dizungu Sugar Estate abstract water in the area of interest upstream of the Mtibwa
EFA site. The Mtibwa Sugar Estate has two current water rights. One is for 1.5 m3/s
year-round from the Diwale River below the junction with the Mkindo River11. It uses
this water to irrigate 5,200 ha with sprinklers. The other water right is for 2.5 m3/s
year-round from the Wami River.12 It currently uses a portion of this water to irrigate
3,000 ha with sprinklers on the south side of the Wami River.

11 Water Right Registration Number 4501 of 1980 (WRBWO 2015). Provisional, renewable every three
years.
12 Water Right Registration Number 4959 of 1990 (WRBWO 2015). Provisional, renewable every three
years.

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ENVIRONMENTAL ASSESSMENT
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 Figure 6.1: Schematic Location and Relation of Factors for EFA Analysis on the Wami River at Mtibwa EFA Site

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-11
Mtibwa Sugar Estate is developing 20,000 ha of new sugar fields on the south side of
the Wami River. By the end of 2016 it will add an additional 3,000 ha to the existing
3,000 ha in this area13. IRRIP estimates that by the end of 2016 the Estate will
consume all of its 2.5 m3/s water right on the Wami River for irrigation of these 6,000
ha.
To develop the remaining 14,000 ha of cultivation, the Mtibwa Sugar Estate has
applied for an additional 7.5 m3/s water right from the Wami River.14 The Estate says
it is in the final stages of receiving that right. The right will be restricted to the wet
season and the Estate plans to abstract from March through May or June.15 This
water will be used to fill two reservoirs with a total capacity of 70 million m3 from
which water will be withdrawn for irrigation during the dry season. The Estate is sure
enough that it will receive the 7.5 m3/s water right that it has invested a significant
amount of capital in the construction of a pump house with 6-pumps on the Wami
River.16 Although the Estate does not have a specific development plan, it is
reasonable to assume that sometime in the next 5 to 10 years it will be abstracting an
additional 7.5 m3/s from the Wami River from March through June, as it will take four
months to fill the reservoirs, if they are doing so at 7.5 m3/s.
The Dakawa irrigation scheme has a water right from the Wami River for 5.0 m3/s
from March through November.17 It currently abstracts 3.5 m3/s but is in the process
of rehabilitating its system and will soon be abstracting from 2.35 to 3.88 m3/s,
depending on the month, at a seasonal average rate of 3.22 m3/s (CDM Smith 2013).
The Mkindo irrigation scheme has a right of 0.624 m3/s (WRBWO 2015), but its
irrigation requirement for the 110 ha it currently irrigates is 0.22 m3/s. The proposed
Mgongola irrigation scheme will require an additional 1.18 m3/s. These abstractions
are based on the assumption of a 2 l/s/ha abstraction rate. If the proposed scheme
is constructed, the two schemes will be managed as one scheme, requiring a total
abstraction of 1.4 m3/s and requiring the current water right to be increased by 0.776
m3/s.
As shown in Figure 6.1, the intake site for the existing Mkindo irrigation scheme is
upstream of the Mkindo gauge (1GB2), which means that the gauge records flows
after the existing extraction. Therefore, abstraction information for the Mkindo
irrigation scheme is included in the analysis for information purposes only.
There is no data available on the abstraction for the Dizungu Sugar Estate, which is
an area of approximately 300 ha. It is reported that the Estate does irrigate with
surface water, but no information is available about the abstraction.
Analysis and Conclusions
Taking all of the above factors into consideration, input-output analysis was
conducted of the impact of the proposed Mgongola scheme on the Mtibwa EFA site
RAD. Table 6.2 presents the results of this analysis.

13 From Mtibwe Sugar Estate General Manager at a meeting at the Plantation with IRRIP and Mtibwa
staff on January 27, 2015.
14 Ibid.
15 Ibid.
16 Observed by IRRIP on January 27, 2015.
17 Water Right Registration Number 4583 of 2007 (WRBWO 2015). Final (permanent).

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Table 6.2: Low-Flow Year Residual Flows and Recommended Average Discharge (RAD) at the Mtibwa EFA Site (m3/s)
(a) (b) (c) (d) (e) (f) (g) (h) (j)
(a+b+c-e-f-g) (h-i)

1-in-5 Year Mkindo Mtibwa Mgongola Residual Driest

Flows Low Flow Low flow Irrigation Sugar Scheme Flow at Year RAD Over or
at Dakawa at Mkindo at Diwale Water Estate Irrigation Additional Mtibwa EFA at Mtibwa Under (-)
Month Period Gauge Gauge* Gauge* Abstraction** Abstraction† Requirement Abstraction Site EFA Site RAD
March 2 10.77 2.50 1.31 0.22 11.50 3.42 1.18 -1.52 3.00 -4.52
April 1 19.70 8.31 7.16 0.22 11.50 2.71 1.18 19.78 5.00 14.78
2 32.57 9.91 12.41 0.22 11.50 3.45 1.18 38.76 5.00 33.76
May 1 39.00 6.45 8.49 0.22 11.50 3.48 1.18 37.78 5.00 32.78
2 25.40 5.90 8.35 0.22 11.50 3.79 1.18 23.18 5.00 18.18
June 1 14.50 4.80 5.99 0.22 11.50 3.88 1.18 8.73 5.00 3.73
2 11.90 3.11 2.73 0.22 11.50 3.14 1.18 1.92 5.00 -3.08
July 1 9.20 2.43 2.00 0.22 4.00 2.76 1.18 5.69 4.10 1.59
2 9.00 2.07 3.19 0.22 4.00 2.35 1.18 6.72 4.10 2.63
Notes:
* Assumes lowest average flow in half month period for Mkindu and Diwale based on 6 years of gauge data at each station.
** For information purposes only, as the abstraction for Mkindo Irrigation is above the Mkindo gauge, so it is already accounted for in the Mkindo flow data.
† From Mtibwa Sugar Estate General Manager at a meeting at the Plantation with IRRIP staff on January 27, 2015.

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-13
As can be seen in Table 6.2 construction of the proposed Mgongola irrigation
scheme will cause the downstream flows to drop below the flow of water that the EFA
has established as being necessary to meet the ecological, geomorphological, and
human domestic requirements (the RAD) during two periods (2nd periods of March
and June).
To test the viability of other irrigation alternatives, the same analysis was conducted
using the irrigation alternative with the least water requirement, the sprinkling
alternative. Assuming that the sprinkling alternative was fully implemented on the
entire 589 ha area, the additional water requirement would be reduced from 1.18 to
0.86 m3/s. The results of this analysis showed the residual flows at the Mtibwa EFA
site would still be lower than the RAD in the 2nd periods of March and June.
This analysis does not include flows from Divue, Dizingwi and Mgongola rivers or any
of the small drainages that flow into the Wami River from the south between the
Dakawa gauge and the Mtibwa EFA site. No data is available for these water
sources. However, it is unlikely that these flows would offset the RAD deficits as
these rivers are minor (and at least in one case intermittent) and they would have to
have a combined flow equal to the gauged flow in the Mkindo River in the 2nd period
of June, and 18% greater than the combined gauged flow of the Diwale and Mkindo
rivers in the 2nd period of March. Neither of these are reasonable assumptions.
In summary, all of the irrigation alternatives will result in significant, immitigable
impacts on downstream water users, both human and ecological. The driving force
behind this outcome is the planned future water consumption needs of the Mtibwa
Sugar Estate. Short of reducing the water rights for the Estate, these impacts cannot
be mitigated. Reducing the rights is unlikely considering the substantial capital
investments the Estate has made and plans to make to use those rights, and the
apparent inability of the WRBWO to allocate rights based on the EFA, in spite of their
stated intention to do so (WRBWO 2015).
Biological Environment
Due to the fact that the project area for the Mgongola irrigation scheme is and will
continue to be a severely human altered landscape, it has very little area that even
approach natural ecosystems within its boundaries. Except for the possible impacts
on the aquatic environment in the rivers, downstream of the project area (discussed
below), there will be no impacts from project operation on the biological environment
outside the boundaries of the irrigation scheme.
Effects on Aquatic Species
Aquatic flora and fauna in the Mgongola, Mkindo and Diwale rivers downstream of
the drainage discharges into the Mgongola River could be impacted by project
operation if water contamination by fertilizers and pesticides become a problem. As
was the case for the potential water quality impacts from fertilizers and pesticides, if
farmers adopt sprinkling under the Sprinkler Irrigation alternative or the SRI
alternative, the potential impacts on aquatic fauna in the rivers would be less than
those of the Proposed Action and the other irrigation alternatives.
Socio-Economic Environment
Land Use Conflicts
As reported in Sections 5.4.2 and 5.4.3, pastoralists from the Kambala village bring
their cattle to the banks of the Mgongola, Dizingwa and Mkindo rivers during the dry
season to gain access to water and to graze their cattle on fallow, rain-fed farmland,
including that in the Mgongola project area. The grazing is primarily done via an
informal agreement, although some farmers may be receiving payment from

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-14
pastoralists for use of their land. Whatever the arrangement is, it has deteriorated in
recent years, causing some conflicts between farmers and cattle herders, even to the
point of violence (de Bruin et al. 2012).
This conflict is likely to increase if the Mgongola irrigation scheme is constructed, as
it is most likely that grazing in the dry season by non-members of the WUA will be
prohibited. Grazing cattle can trample the irrigation infrastructure such as canals and
bunds and disrupt field leveling. If the cattle are owned by the farmers, then they
have an incentive to manage them so as not to trample the infrastructure. But if the
cattle are owned by others, no such incentive exists. The nearby Dakawa Rice Farm
tried to manage grazing by non-member herders, but after several unsuccessful
attempts, decided to prohibit it instead.
Water Use Conflicts
Local water use conflicts were identified in the Scoping Statement as a potentially
significant impact of the project. Upon further evaluation, however, it was determined
that no local water use conflicts would be created by implementation of the project,
except those associated with watering cattle, which are addressed in the preceding
paragraphs on “Land Use Conflicts.”
Increase in Water-Related Diseases
Increase in water-related diseases was identified in the Scoping Statement as a
potentially significant negative impact; however, after further investigation it has
determined that the project could have no impact on these diseases or even lead to a
decrease rather than an increase in water-related diseases.
Although there are many water-related diseases, many of them are transmitted via
ingestion (typhoid, cholera, dysentery and worms), which will not be impacted by
construction of the Mgongola irrigation scheme. Other diseases, however, which are
transmitted by hosts that breed in stagnant water (e.g., schistosomiasis [bilharzias],
malaria, filariasis, sleeping sickness and yellow fever diseases), have been
associated with irrigation. Of these, malaria is the most relevant for the Mgongola
irrigation scheme, as it is the most prominent water-related disease in the Mvomero
district, representing 50% of all reported disease cases. Mosquitos that transmit
malaria breed in stagnant water.
The project area is already used for paddy rice production, so the area is already
often ponded with stagnant water, providing mosquito breeding grounds. By
improving the ability of farmers to manage water, the length of time that water is
ponded in the fields will increase, at least during the period when having ponded
water in the fields is desirable (e.g., during the active growing period). However, by
improving the drainage in the fields, farmers will be able to remove ponded water
when it is not desirable (e.g., before and during harvest). So it is not clear if the
project will increase or decrease breeding periods. Indeed, it may only change the
timing of when water is ponded in the fields rather than increasing or decreasing the
total time of ponding.
In addition, recent research has suggested that the simple link between irrigation and
increased malaria may not be nearly as simple as it appears:
It has often been assumed that high numbers of malaria vector Anopheles
mosquitoes (Diptera: Culicidae) resulting from irrigation schemes lead
inevitably to increased malaria in local communities. However, recent studies
in Africa have revealed a more complex picture. Increased numbers of
vectors following irrigation can lead to increased malaria in areas of unstable
transmission, where people have little or no immunity to malaria parasites,

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-15
 such as the African highlands and desert fringes. But for most of sub-
Saharan Africa, where malaria is stable, the introduction of crop irrigation has
little impact on malaria transmission. Indeed, there is growing evidence that
for many sites there is less malaria in irrigated communities than surrounding
areas. The explanation for this finding is still unresolved but, in some cases at
least, can be attributed to displacement of the most endophilic and
anthropophilic malaria vector Anopheles funestus Giles by An. arabiensis
Patton with lower vectorial capacity, as the latter thrives more than the former
in ricefields. (Ijumba and Lindsay 2001)
These findings have been supported by subsequent, similar research (Ijumba et al.
2002, Muturi et al. 2008 and Mwangangi et al. 2010).
Scheme Management Capacity
The main challenge to the sustainability and efficient operation and management of
the Mgongola irrigation scheme is the capacity of WUA to properly manage it. The
WUA is a new organization, but it will benefit from having in its membership the
members of the Mkindo irrigation scheme cooperative, which will be merged into the
new WUA.
MZITSU is coordinating the setting-up and training of the combined WUA, in
cooperation with the Mvomero LGA and NAFAKA. They are in the process of
helping the WUA:
 Secure a consolidated land tenure certificate.
 Develop a training program.
 Establish financial management procedures, including collection of water
fees and other dues. Water measurement structures are being included in
the designs, but the WUA will need to develop a system to charge farmers
for actual water consumed.
 Establish water management practices and cropping patterns for the
scheme.
 Develop support for post-harvest processing and marketing.
But as this is a brand new WUA, it will be necessary, for the GoT and USAID to
continue to provide institutional capacity building assistance in the first several years
of its operation.
WRBWO Capacity to Control Water Abstractions
WRBWO has responsibility for monitoring water flows and granting water rights. It
also has the authority to restrict water withdrawals if flows are impacted. It does not,
however, have all the resources necessary to fully monitor flows. The GoT as well as
international donors are aware of this problem and are working to solve it. The GoT’s
Water Sector Development Program (WSDP), supported by several international
donors, has been in effect since 2007 and has a capacity building program for Water
Basin Offices. The WRBWO has been a recipient of this capacity building and its
capacity to monitor and regulate water use has increased. JICA is currently
conducting a capacity assessment of WRBWO to identify area requiring more
assistance. iWASH has a program component to develop low cost remote
instrumentation for monitoring flows, abstractions, discharges etc.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-16
Land Ownership
Land ownership was identified in the Scoping Statement as a potentially significant
impact of the project. Upon further evaluation, however, it was determined that no
land ownership issues would be created by implementation of the project.
Change of Community Lifestyle
Construction and use of an irrigation scheme for 589 hectares in the Mgongola
project area will increase incomes in the nearby villages of Mkindo, Dihombo and
Hembeti. These are very poor villages, so increased incomes will primarily have a
positive impact on the villages. The potential positive impacts of increased income
from irrigation can be seen when comparing the community lifestyle in Dakawa
village (which is reliant on irrigated paddy rice as the primary source of income) with
that in Mkindo and Hembeti villages (which are dependent largely on rain-fed rice
production). Dakawa village is clearly more prosperous than the other two villages
(Keraita 2012).
Increased incomes in the villages, however, may also create problems, particularly if
it causes in-migration. The project area, however, is already cultivated and those
cultivating the area will be the recipients of the project benefits, so no new
agricultural land will be made available, thus limiting the potential for in-migration.
Increased rice production in the project area could create demand for wage laborers.
Much of this demand will be met by family members, but there may be some influx of
wage laborers during planting (particularly if seedling planting is adopted) and
harvest. It is unlikely that this demand will cause permanent or significant in-
migration.

6.3 Impacts of Improved Intensified Rain-Fed Agriculture Alternative

6.3.1 Impacts During Mobilization and Construction
There will be no impacts from mobilization and construction for the Improved
Intensified Rain-Fed Agriculture alternative because it calls for no construction.
6.3.2 Impacts During Operation
6.3.2.1 Positive Impacts
Increased Rice Production
As noted in Section 3.4.3, rain-fed paddy rice production in the project area was
reported as 1.6 mt/ha in the JICA study (JICA 1998). The same study reported that
FAO program had a program in the area at the time of the study that worked with
rain-fed farmers to improve their yields. The farmers in the project grew rain-fed
paddy rice with improved seed and fertilizer and herbicide inputs, which resulted in
an average yield of 3.2 mt/ha (JICA 1998, Table 1.3.2). Thus, for this EA we have
assumed that improved farming practices alone will result in a production level of 3.2
mt/ha.
Opportunities for Employment
Similar as the Proposed Action, but at a lower level as no WUA employment
opportunities will be created and potential rice yields and associated incomes will be
lower than for any of the irrigation alternatives.
6.3.2.2 Negative Impacts
The Improved Intensified Rain-Fed Agriculture alternative will not address the current
problems of flooding and waterlogging, as it will involve no construction projects

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-17
including flood protection and drainage. Other negative impacts will be similar to
those of the Proposed Action.
Effects of Pesticide and Fertilizer Use
Same as the Proposed Action.
Water Contamination
Same as the Proposed Action.
Effects on Aquatic Fauna
Same as the Proposed Action.
Land Use Conflict
Less than the Proposed Action. The existing conflicts will continue, but they will not
be exacerbated by the need to eliminate grazing from the area, as there will be no
irrigation infrastructure that will be damaged by grazing.
Change of Community Lifestyle
Similar as the Proposed Action, but at a lower level as the economic benefits will be
less than for any of the irrigation alternatives.

6.4 Impacts of No Action

Under the No Action alternative the farmers would continue to cultivate rain-fed
paddy rice. They would continue to have problems with flooding and water logging
and would produce low yields. As the impacts of climate change are realized,
farmers will experience increasing uncertainty of the onset of rainfall and its
regularity, which will most likely reduce their yields. Thus the already poor villages in
the area could become even poorer.

6.5 Significant Impacts

The previous sub-sections have identified several direct and indirect environmental
impacts that are expected from implementation of the Proposed Action or its
alternatives. With the application of the specific mitigation measures shown in
Section 7.1, none of these impacts are anticipated to be significant. However, four
impacts do warrant special concern and follow-up monitoring:
 Water quantity impact to downstream users and ecosystems;
 Effects of pesticides and fertilizer use;
 Land use conflicts between cultivation and grazing; and
 WUA’s capacity to manage the scheme.
IRRIP1 conducted an analysis (Annex D) of the impacts of water withdrawals on
downstream users (human and ecological) on the Wami River using the
environmental flow assessment studies and the best information available on flows
and abstractions. That analysis indicates that there will be a significant immitigable
impact on downstream users in two periods (2nd periods of March and June) from the
withdrawals associated with any of the irrigation alternatives. This impact exists, but
at a lower magnitude, for the non-irrigation alternatives as well (Improved Intensified
Rain-Fed Agriculture and No Action), indicating that this is an existing condition
caused by planned over allocation of the flow to other users. The non-irrigation
alternatives, however, will not aggravate that existing condition.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-18
Pastoralists from the Kambala village bring their cattle to the banks of the Mgongola,
Dizingwa and Mkindo rivers during the dry season to gain access to water and to
graze their cattle on fallow, rain-fed farmland, including that in the Mgongola project
area. The grazing is primarily done via an informal agreement, although some
farmers may be receiving payment from pastoralists for use of their land. Whatever
the arrangement is, it has deteriorated, causing some conflicts between farmers and
cattle herders in recent years, even to the point of violence (de Bruin et al. 2012).
This conflict is likely to increase if the Mgongola irrigation scheme is constructed, as
it is most likely that grazing in the dry season by non-members of the WUA will be
prohibited. Local Government Authorities and the Morogoro Zonal Irrigation and
Technical Services Unit will need to work with the WUA and the herders from
Kambala to develop acceptable alternatives for securing access to water and feed for
the cattle during the dry season.
The assessment of fertilizer and pesticide use on the local rivers and their
ecosystems at and downstream from the Mgongola project area was based on
professional judgment, as there is no water quality data for the river in the vicinity of
the of the project area that would allow analysis. It would be prudent to collect water
quality data and do an analysis of these impacts during at least one cropping season.
If a problem is identified, then a subsequent routine monitoring program should be
established and on-farm use controls implemented.
The long-term success of the irrigation scheme is dependent upon the capability of
the newly formed WUA to manage it. IRRIP1 does plan to provide the WUA with
operator training and an operations manual. In addition, the GoT and the USAID-
funded NAFAKA Project has helped establish the WUA. But as this is a brand new
WUA, it will be necessary, for the GoT and USAID to continue to provide institutional
capacity building assistance in the first several years of its operation.

6.6 Irreversible or Irretrievable Commitments of Resources

There are no irreversible or irretrievable commitments of land resources associated
with irrigating the project area. The land on which the project is located was
converted from a natural landscape to a human landscape many years ago.
The significant impact on downstream water users is not irreversible on two counts.
First, the water resource in the project area (see Figure 6.1) are allocated by the
WRBWO as a right to use the water, and WRBWO can withdraw that right
temporarily in the case of drought, or permanently if it is determined to be needed for
other uses (human or ecological). Second, the planned additional abstractions for
other projects have not yet occurred and could still be denied, however, doing so
would be difficult given the significant capital investments that have already been
made to use those resources.

6.7 Possible Conflicts with Land Use Plans, Policies and Controls for the
Area
The proposed activities all fall within the current land use plans, policies and controls
for the land on which it is located.

6.8 Cumulative Impacts

The cumulative impact of most concern for the project is that on water quantity in the
Wami River. The analysis presented in “Water Quantity Impacts on Downstream
Users and Ecosystems” subsection of Section 6.2.2.2 and Appendix D shows the
cumulative impact on water quantity of this project and other known or planned
abstractions in the relevant watershed. There is one other abstraction that has been
discussed in the watershed which was not included in these analyses, the proposed
ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-19
expansion of the Dakawa irrigation scheme. If this abstraction was included, it would
just further strengthen the conclusion that there is not adequate water in the
watershed for any further irrigation development.

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 6-20
7 ENVIRONMENTAL MITIGATION AND MONITORING
7.1 Mitigation Measures
This section of the EA presents the mitigation measures that are necessary to reduce
or minimize the impacts of the project. It builds on the general mitigation measures
presented in Table 4.7 and Table 4.8, but are considerably more detailed, including
what is to be done by whom, and who will monitor their implementation. Table 7.1
presents the mitigation measures for mobilization and construction activities and
Table 7.2 presents the mitigation measures for operation.
All of the mitigation measures for mobilization and construction activities will be
implemented by the construction contractor(s) via clauses in the contract(s). The
implementation of these mitigation measures will be monitored by IRRIP1, which has
the responsibility for overseeing implementation of the construction contracts.
Other than providing some training in system operation at the time of commissioning,
and the development of operation and maintenance plans for the WUA, IRRIP1,
under its current contract, will not be involved in system operation. The irrigation
scheme will be operated by WUA, its future owner. Implementation of the
operational mitigation measures will largely rest with WUA and other GoT agencies;
however, in some cases other USAID projects, such as NAFAKA and iWASH, may
be involved in supporting the WUA and the WRBWO in the implementation of
mitigation measures.

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-1
 Table 7.1: Mobilization and Construction Mitigation Measures for the Proposed Action and All Irrigation Alternatives
Timing &
Responsible
Parties for
Impact Specific Mitigation Measure How Monitored Monitoring
Soil Erosion SE1. Land clearance shall be limited to the minimum needed for the irrigation, drainage,
flood control, and road infrastructure.
SE2. Avoid executing excavation works under aggressive weather conditions.
SE3. Erect temporary erosion control barriers around work sites during site preparation
and construction to direct runoff away from the site in a manner that will minimize
At Least Monthly
erosion.
SE4. Stabilize and compact the soils in canals and on embankments after completion of Routine Site
IRRIP1 Project
each stage of works. Inspections
Manager
SE5. Return road beds, drainages and surfaces disturbed during construction to their
original (or better) condition.
SE6. Place clear markers indicating the limits of the construction trenches and
stockpiling area of excavated materials to restrict equipment and personnel
movement, thus limiting the physical disturbance to land and soils in adjacent
areas.
Conclusion of
individual works
SE7. Revegetate canal and flood control embankments, drain outfalls and other Routine Site
disturbed area at the conclusion of construction activities. Inspections
IRRIP1 Project
Manager
SE8. Every effort shall be made to secure borrow materials from existing, government
Mobilization Period
approved sites.
Borrow Site
SE9. Develop new sites, if necessary, in agreement with the village government or
Location Approval IRRIP1 Project
owners and with government or IRRIP1 approval. New sites should be developed
Manager
on non-agricultural or unproductive land.
SE10. Close borrow pits that are no longer in use by backfilled with approved materials At Closure
and/or landscaping, or turning them into water storage points for livestock. Routine Site
SE11. In all cases, grade the edges of the pits to ensure safe access for children and Inspections IRRIP1 Project
livestock. Manager

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-2
 Table 7.1: Mobilization and Construction Mitigation Measures for the Proposed Action and All Irrigation Alternatives
Timing &
Responsible
Parties for
Impact Specific Mitigation Measure How Monitored Monitoring

Soil Pollution SS1. Use vehicles and equipment which are in good condition and properly service and
check them to make sure that they do not leak lubricants and fuels.
SS2. Use drip pans to contain all hydrocarbon leakages on construction equipment. At Least Monthly
SS3. Machine refueling shall be carried out only at designated areas.
Routine Site
SS4. Selection vehicle routes wherever possible to avoid passing through agricultural IRRIP1 Project
Inspections
fields. Manager
SS5. Store and handle fuels and lubricants within containment facilities (e.g. bounded
areas, leak proof trays, etc.) designed to prevent the release of spilled substances
to the soil. These facilities should be maintained and kept drained of rainwater.
SS6. Develop and implement a Contractor’s Site Environment, Health and Safety Plan
(SEHASP) including the following:
- Procedures for storage and handling of hazardous substances (e.g. batteries, Approval of Plan
IRRIP1 Project
chemicals, fuel) Prior to
Manager
- Designs and siting requirements for on-site maintenance, refueling and Mobilization
cleaning of vehicles and equipment, if needed, including the provision of
containment of leaks and discharges.
- Spill procedures and response kits for containment of spills and removal and
disposal of contaminated soils
At Least Monthly
- Designation of concrete batching areas with proper isolation from the soil Compliance with
surface, if needed. Plan via Routine
IRRIP1 Project
- Cleaning of concrete ready-mix vehicles on-site in specially prepared places Site Inspections
Manager
where the concrete wastes are contained and disposed of at an IRRIP1-
approved site.
Loss of Topsoil LT1. If fill material is removed from fields, the top 200 mm (or as appropriate for each
At Least Monthly
field) of top soil should first be moved to one side before taking suitable fill material
Routine Site
from beneath the top soil layer.
Inspections IRRIP1 Project
LT2. After the required fill has been removed, the land shall be leveled to ±10 mm and
Manager
the topsoil should be returned to the field and also leveled to ±10 mm.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-3
 Table 7.1: Mobilization and Construction Mitigation Measures for the Proposed Action and All Irrigation Alternatives
Timing &
Responsible
Parties for
Impact Specific Mitigation Measure How Monitored Monitoring
Water Implementation of Mitigation Measures for Soil Erosion, Soil Pollution, and Generation of
Contamination Solid Waste plus the following: At Least Monthly
WC1. No vehicle or machine refueling shall be carried out within 100 m of a water Routine Site
source. Inspections IRRIP1 Project
WC2. Provide improved pit latrines in the field areas for workers. These latrines will Manager
remain after construction for use by farmers.
Generation of SW1. Organic matter resulting from site clearance shall be disposed of in sites approved
Solid Waste by IRRIP1 where any of the following methods can be applied: Approval of Plan
- Burying/composting for soil conditioning; IRRIP1 Project
Prior to
- Controlled burning; or Manager
Mobilization
- Dried and used in farms to control growth of unwanted weeds
SW2. Allocate a special area for petty business such as food stalls and provide garbage
bins.
SW3. Solid wastes generated from construction activities will be collected and disposed At Least Monthly
of in a site whose size and location will be determined by the IRRIP1 Project Compliance with
Manager in agreement with villagers. Decomposable materials will be buried. Plan via Routine
IRRIP1 Project
Plastics and other recyclable materials will be collected and sent for recycling in Site Inspections
Manager
Morogoro town. Hazardous waste will be disposed of in accordance with
Mitigation Measure SS6.
SW4. Practice good housekeeping at works sites to minimize wastes generated.
At Least Monthly
SW5. Post appropriate signage such as “DO NOT LITTER” or “USITUPE TAKA” at all
Routine Site
strategic sites.
Inspections IRRIP1 Project
SW6. All excavated spoils should be well managed through levelling or tipped into
Manager
borrow areas which are no longer useful.
Dust and Air DAP1. Construction machines/equipment shall be well-maintained to ensure optimum fuel
Pollution combustion. All the vehicles shall be frequently checked and serviced during the
whole rehabilitation period so that the levels of exhaust emissions are reduced. At Least Monthly
DAP2. Movement of vehicles shall be kept to a minimum necessary for completing the Routine Site
job. Inspections IRRIP1 Project
DAP3. Ensure site roads are kept regularly damped down, compacted or suitably Manager
surfaced to minimize dust emissions from vehicle use.
DAP4. Avoid idling vehicles and equipment engines that are left running unnecessarily.
ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-4
 Table 7.1: Mobilization and Construction Mitigation Measures for the Proposed Action and All Irrigation Alternatives
Timing &
Responsible
Parties for
Impact Specific Mitigation Measure How Monitored Monitoring
Noise Pollution Approval of Plan
NP1. Locate the machinery yard in an area which is not too close to residential IRRIP1 Project
Prior to
premises. Manager
Mobilization
NP2. Vehicles and equipment shall be fitted with noise silencers such as mufflers and
serviced regularly to ensure that they are operating at manufacturers’
specifications. At Least Monthly
NP3. During construction works, the contractor should only work during approved hours Routine Site
so that villagers living close to the site are not disturbed during sleeping and Inspections IRRIP1 Project
resting hours. Manager
NP4. Prior to initiating the works near noise sensitive receivers, notify residents of the
plans, including expected duration.
Effects on the At Least Monthly
Aquatic Fauna Mitigation Measures for Water Quality Routine Site
Inspections IRRIP1 Project
Manager
Displacement of
Economic Approval of Plan
IRRIP1 Project
Activities DEA1. Schedule construction activities to minimize impacts on current farming activities. Prior to
Manager
Mobilization

Disturbance of
Graves Approval of Plan
DG1. Develop and implement procedures for respectfully handling the disturbance of IRRIP1 Project
Prior to
any grave sites encountered during construction. Manager
Mobilization

Worker/Community
Health and Safety Approval of Plan
IRRIP1 Project
Impacts Prior to
Manager
Mobilization

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-5
 Table 7.1: Mobilization and Construction Mitigation Measures for the Proposed Action and All Irrigation Alternatives
Timing &
Responsible
Parties for
Impact Specific Mitigation Measure How Monitored Monitoring
HS1. Develop and implement a Contractor’s SEHASP addressing work place health and
safety issues, including:
- A reporting program for occupational injuries, illnesses, accidents and near
misses; At Least Monthly
Compliance with
- Protocols for investigating occupational injuries, illnesses, accidents and near
Plan via Routine
misses; IRRIP1 Project
Site Inspections
- A sensitization program for workers and community residents to reduce the Manager
spread of STDs, STIs and HIV/AIDS; and
- A sensitization program for community residents, including children, on the
dangers at the construction sites.
HS2. Identify and provide appropriate personal protective equipment (PPE) that offers
adequate protection to the workers including eye protection, dust masks, hard hats,
gloves, high visibility jackets, hearing protection equipment, proper clothing, safety
boots, safe ladders, etc. At Least Monthly
HS3. Properly maintain PPE, including cleaning when dirty and replacement when Routine Site
damaged or worn out. Inspections IRRIP1 Project
HS4. Train all employees working in the project in the proper use PPE when at work to Manager
avoid occupational risks.
HS5. Train all employees working in the project in the implementation of Mitigation
Measure SS6
Change of At Least Monthly
Community CCL1. Sensitize workers to community by laws and expected, proper behavior in Routine Site
Lifestyle communities. Inspections IRRIP1 Project
Manager

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-6
 Table 7.2: Operation Mitigation Measures for the Proposed Action and All Action Alternatives
Timing &
Responsible
Implemented Parties for
Impact Specific Mitigation Measure By How Monitored Monitoring
Soil Salinity End of irrigation
(Sprinkler SS1. Monitor soil salinity at the end of each irrigation season and take season
WUA Soil Sampling
Irrigation) remedial actions if salinity reaches critical levels.
WUA
Effects of Whenever such
Pesticides and assistance is
NAFAKA
Fertilizer Use PF1. Comply with the conditions of the NAFAKA PERSUAP when given
PERSUAP
providing any assistance to Mgongola farmers that might include NAFAKA
Reporting
training on, discussing or promotion of the use of pesticide inputs. NAFAKA staff
Requirements
and/or
consultants
Whenever such
assistance is
PF2. Sensitize Mgongola farmers about the proper application of fertilizers given
NAFAKA Annual
and the impacts improper use can have on the Mkindo and Mgongola NAFAKA
Reports
rivers NAFAKA staff
and/or
consultants
Annually during
Sampling,
PF3. Water quality monitoring for nutrients and pesticide residues above the irrigation
Laboratory
the Mkindo diversion and below the discharges from the irrigation WRBWO period
Analysis and
scheme drains
Reports
WRBWO
Water
Contamination Mitigation Measures for Effects of Pesticides and Fertilizer Use

Monthly
WQ1. Monitor water withdrawals by Mgongola irrigation scheme WUA Daily logs
WRBWO

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-7
 Table 7.2: Operation Mitigation Measures for the Proposed Action and All Action Alternatives
Timing &
Responsible
Implemented Parties for
Impact Specific Mitigation Measure By How Monitored Monitoring

Water Quantity WQ2. Monitor all water withdrawals on the Wami River and its tributaries Abstractor
Impacts to from the Dakawa Gauging Station (1G1) to the Mtibwa EFA site during Records or Field
Semi-monthly
Downstream March through July Measurements
Users and WQ3. Monitor flows during March through July at the Dakawa Gauging
WRBWO
Ecosystems Station (1G1), Mkindo Gauging Station (1GB2), Diwale Gauging Gauging stations
WRBWO
(Irrigation Station (1GB1A) and the Mtibwa EFA site
Alternatives) Annually
WQ4. Use the data from WQ1 through WQ3 to do an analysis of status of
the RAD at the Mtibwa EFA and the impact upon it of the DRF and the Report
WRBWO
other withdrawals.
WUA
Effects on
Aquatic Mitigation Measures for Effects of Pesticides and Fertilizer Use
Species
Land Use LUC1. Creation of a livestock corridor on through which animals can be Creation of the During
Conflicts herded to reach the rivers for water. Corridor construction and
LUC2. Designation of grazing and watering areas outside of the project mobilization
LGA, MZITSU
boundaries, in between the flood control structures and the banks of Designation of period
in collaboration
the rivers areas
with WUA and
LGA, MZITSU
Kambala
LUC3. Establishment of an NGO composed of farmers and herders to pastoralists Establishment of
Annually
address cultivation/grazing conflicts, modeled on the Kambala NGO
association known as KIPOK, a Maasai word literally means Minutes of
LGA, MZITSU
“healing”. meetings
Capacity of MZITSU and Monthly
WUA IRRIP1* or WUA Board
CWU1. Develop and support an institutional capacity building program for the
other USAID- Minutes IRRIP1* or other
(Irrigation WUA
funded Project Site Visits USAID-funded
Alternatives)
Project

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-8
 Table 7.2: Operation Mitigation Measures for the Proposed Action and All Action Alternatives
Timing &
Responsible
Implemented Parties for
Impact Specific Mitigation Measure By How Monitored Monitoring

Annual Reports Annual

CWU2. Report to the MZITSU and the MAFC on revenue collection for
WUA Board to MZITSU and
system operation and maintenance.
MAFC MZITSU
Capacity of WSDP Annually
CWO1. Continue capacity building for the WRBWO, responding to the
WRBWO WSDP Monitoring
specific recommendations in the JICA capacity assessment.
Framework MoW
(Irrigation
Alternatives) CWO2. Deploy and pilot the use of remote instrumentation for monitoring Annual
Work plans
flows, abstractions, discharges etc. on the Mkindo River and the iWASH
Annual reports
Mtibwa EFA site. USAID
Note:

* Providing this type of technical assistance is not currently in the CDM Smith contract with USAID for implementation of IRRIP1.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-9
7.2 Monitoring
Two types of monitoring will be necessary to ensure that this project will have the
limited environmental impacts that have been identified in this EA: mitigation
monitoring and resource monitoring.
Mitigation monitoring will ensure that the mitigation measures are implemented.
Monitoring of implementation of the mitigation measures during mobilization and
construction have been included in Table 7.1. IRRIP1 has responsibility for
monitoring the implementation of all of these mitigation measures in its role as the
Project Manager during construction (i.e., Supervising Engineer). Reporting on the
implementation of these mitigation measures will be done through IRRIP1’s Quarterly
Progress Reports to USAID.
Monitoring the implementation of the mitigation measures for operation is to be
undertaken by various entities, as identified in Table 7.2.
Resource monitoring is undertaken to ensure that the impacts to the environment are
as predicted in the EA. For the construction of the Mgongola irrigation scheme, two
types of resource monitoring have been identified: water quality monitoring and
water flow monitoring. This monitoring is to be undertaken to ensure that the
predicted results were accurate for the impact of pesticides and fertilizers on the
Wami River and the impact of DRF withdrawals on the environmental flow in the
Wami River.
The water quality monitoring required for this project is embedded in the mitigation
measures as Measure PF3 in Table 7.2. This monitoring will be undertaken by
WRBWO. It should be done at least during one irrigation season. If a problem is
identified, then a subsequent routine monitoring program should be established and
on-farm use controls implemented with WUA.
The water quality monitoring required for this project is embedded in the mitigation
measures as Measures WQ1, WQ2, WQ3 and WQ4 in Table 7.2. This monitoring is
also to be undertaken by WRBWO. It should be done annually during the months
when the irrigation scheme is abstracting water (March through July).

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 7-10
8 LIST OF PREPARERS
CDM Smith Team
Eng. Keith F. Williams, P.E., Chief of Party
Mr. Lane Krahl, Environmental Impact Specialist
Eng. Chris Hall, Senior Irrigation Engineer
Mr. Peter Ede, Senior Hydrologist
Ms. Katherine Spink, Hydrologist

Environmental BENCHMARK Team (subcontractor to CDM Smith)

Eng. Venant Rwenyagira, Team Leader, Registered Environmental Expert
Mr. Huruma Kisaka, Sociologist
Mr. Frank Mbago, Ecologist
Ms. Zukira Mbaraka, Assistant Environmental Impact Assessment Expert
Ms. Greven Msenga, Assistant Sociologist and Mass Communication Expert

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 8-1
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Amphibians of East Africa, A&C Black, London.
SRI International Network and Resources Center (SRI-RICE). 2014. College of
Agriculture and Life Sciences, Cornell University. http://sri.ciifad.cornell.edu/
accessed on June 11, 2014.
Stockbauer, Bette, 1999. A Review of the Literature: Supporting a Rationale for
Mpingo Conservation. June 1999. African Blackwood Conservation Project

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME 9-4
 website, http://www.blackwoodconservation.org/review.html accessed on 20
November 2013.
Subsidiary Legislation (Suppl. No. 16 of 4th May 2001).
Tanzania Bureau of Standards – National Environmental Standards Compendium
(NESC).
Tanzania Coastal Management Partnership (TCMP), 2008. A Profile of the Wami
River Sub-Basin. Coastal Resources Center at the University of Rhode
Island, for USAID, June 2008. 28pp.
Trulio, L. 2000. Basics of Bird Conservation in the U.S., US Environmental
Protection Agency (EPA)
United Republic of Tanzania. 2005. Environmental Impact Assessment and Audit
Regulations. Minister of State, Vice President’s Office, (Environment and
Union Matters), Dar es Salaam, Tanzania. 53pp.
United Republic of Tanzania. 2004. Environmental Management Act, 14 July 2004,
Dar es Salaam, Tanzania. 158pp.
United Republic of Tanzania. 2003. 2002 Population and Housing Census - General
Report, January 2003.
United States Government. 2013. Environmental Procedures. Code of Federal
Regulations, Title 22 Foreign Relations, Volume 1, Chapter II Agency for
International Development, Part 216 Environmental Procedures (22CFR216),
4 April 2013 Edition. pp 976-989.
USAID. 2011. Tanzania FY 2011–2015 Multi-Year Strategy. Feed the Future.
Approved 22 February 2011. 47pp.
USAID. 2010. Initial Environmental Examination of the “Feed the Future” program.
Approved 15 December 2010. 47pp.
USAID. 2007. Environmental Guidelines for Small-Scale Activities in Africa.
Wami/Ruvu Basin Water Office (WRBWO). 2015. Report on Water Use in Wami
Subcatchment. 23 January 2015. 6 pp.
World Bank Group, 1998. Pollution Prevention and Abatement Handbook.
Zitske, B. P., M. G. Betts and A. W. Diamond. 2011. Negative Effects of Habitat
Loss on Survival of Migrant Warblers in a Forest Mosaic, Conservation
Biology, Volume 10.1111/ Pg.No.1523-1739.

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ANNEX A: NEMC’S SCOPING REPORT APPROVAL

ENVIRONMENTAL ASSESSMENT
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ENVIRONMENTAL ASSESSMENT
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ANNEX B: FAUNA OBSERVATIONS IN AND NEAR THE
PROJECT AREA
Bird Species
In total 38 bird species were recorded, some 29 within the Mkindo Forest Reserve,
mostly within miombo woodland and 9 in the rice farms and grassland in and around
the project area. All observed birds were widespread throughout Tanzania and
common in more open habitat types, such as woodland and grassland. No species
were noted to be threatened to extinction as listed by IUCN.

Table B.1: Bird Observations In and Near the Project Area

Species Common Name
Scopus umbretta Hammerkop
Bostrychia hagedash Hadada Ibis
Gypohierax angolensis Palm-Nut Vulture
Circaetus fasciolatus Southern Banded Snake Eagle
Stephanoaetus coronatus African Crowned Eagle
Numida meleagris Helmeted Guinea Fowl
Poicephalus cryptoxanthus Brown-Headed Parrot
Strix woodfordii African Wood Owl
Caprimulgus sp Nightjar
Apaloderma narina Narina Trogon
Alcedo semitorquata Half-Collared Kingfisher
Phoeniculus purpureus Green Wood Hoopoe
Bycanistes bucinator Trumpeter Hornbill
Tockus alboterminatus Crowned Hornbill
Stactolaema olivacea Green Barbet
Dendropicos fuscescens Cardinal Woodpecker
Psalidoprocne holomelas Black Sawwing
Hirundo abyssinica Lesser Striped Swallow
Motacilla clara Mountain Wagtail
Pycnonotus barbatus Common Bulbul
Muscicapa caerulescens Ashy Flycatcher
Terpisphone viridis African Paradise Flycatcher
Dryoscopus cubla Black-Backed Puff Back
Laniarius aethiopicus Tropical Boubou
Prionops scopifrons Chestnut Fronted Helmet Shrike
Dicrurus adsimilis Fork-Tailed Drongo
Oriolus larvatus Black-Headed Oriole
Oriolus chlorocephalus Green-Headed Oriole
Onychognathus morio Red-Winged Starling

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 Table B.1: Bird Observations In and Near the Project Area
Species Common Name
Ploceus bicolor Dark-Backed Weaver
Euplectes ardens Red-Collared Widowbird
Euplectes capensis Yellow Bishop
Euplectes orix Southern Red Bishop
Uraeginthus sp Cordon-Bleu
Lagonosticta rubricata African Fire Finch
Lonchura cucullata Bronze Mannikin
Vidua macroura Pin-Tailed Whydah
Vidua chalybeata Village Indigo Bird
Source: Bracebridge, 2006

Mammal Species
Fourteen mammal species were observed, 13 within the nearby Mkindo Forest
Reserve and one (a resident group of Syke’s monkey) on the edge of the rice farms.
Five primate species were seen and/or heard. The track of a large antelope was
found leading down a steep slope to the Dizingwi river. The identity is uncertain, but
it may be waterbuck, sable or kudu. The most commonly encountered species was
yellow baboons (Papio cynocephalus). One primate species, the Zanzibar galago
(Galagoides zanzibaricus), is near-endemic to the nearby Eastern Arc Mountains and
is Vulnerable to extinction as listed by IUCN.

Table B.2: Mammal Observations In and Near the Project Area

Species Common Name
Colobus angolensis palliatus Black and White Colobus
Papio cynocephalus Yellow Baboon
Cercopithecus mitis monoides Syke's Monkey
Otolemur crassicaudatus Greater Galago
Galagoides zanzibaricus Zanzibar Galago
Thryonomys sp Cane Rat
Cricetomys gambianus Giant Pouched Rat
Herprestes sanguinea Slender Mongoose
Atilax paludinosus Marsh Mongoose
Heterohyrax brucei Bush Hyrax
Potamochoerus larvatus Bushpig
Tragelaphus scriptus Bushbuck
Unknown, track only Large Antelope, such as Waterbuck,
Kudu or Sable
Source: Bracebridge, 2006

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Reptile Species
Six reptile species were observed in and around the project area but none of them
are endemic or threatened by extinction, as listed by IUCN or CITES.

Table B.3: Reptile Observations In and Near the Project Area

Species Common Name
Agama agama Red-Headed Agama
Python natalensis Southern African Rock Python
Philothamnus sp Green Snake
Mabuya cf varia Variable Skink
Varanus niloticus Nile Monitor
Bitis gabonica Gaboon Viper
Source: Bracebridge, 2006

Amphibian Species
Four amphibian species were observed. None of them are threatened to extinction
as listed by IUCN and CITES, although it is likely with revisions that Callulina cf kreffti
will have a categorization of Endangered or Critically Endangered (IUCN).

Table B.4: Amphibian Observations In and Near the Project

Area
Species Common Name
Arthroleptis stenodactylus Common squeaker
Bufo cf guttaralis Toad
Callulina cf kreffti Warty frog
Phrynobatrachus sp Puddle frog
Source: Bracebridge, 2006

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ANNEX C: RELEVANT SECTIONS OF THE SCOPING
STATEMWENT
3 SCOPING METHODOLOGY
The methodology used for scoping consisted of:
 Review of relevant and available literature;
 Field reconnaissance work to become familiar with the project area and to
“ground-truth” baseline conditions and impressions; and
 Consultations with stakeholders.
3.1 Literature Review
IRRIP1 reviewed literature on the potential environmental impacts of lowland rice
irrigation schemes, relevant reports on previously proposed irrigation schemes in the
area, and existing baseline conditions to understand the situation and the potential
environmental and socio-economic issues that are relevant to the construction of the
Mgongola irrigation scheme. The literature reviewed included:
 Project documents relevant to the proposed action;
 Prior, relevant environmental assessments completed in Tanzania;
 USAID and other international guidelines on lowland rice irrigation
schemes and their environmental impacts; and
 Available baseline documentation on the environmental and socio-
economic conditions of the project area.
A list of documents reviewed is provided in Section 9 [of the Scoping Statement].
3.2 Field Work
Several field reconnaissance trips were conducted to observe and record information
on the existing irrigation system and the environmental and social conditions in the
project area. During these trips the Scoping Statement Team also had informal
conversations with farmers and local residents about the current situation.
3.3 Consultations
Meetings were held with stakeholders in the project area to provide information on
the project and to solicit inputs on perceived issues and problems that may be
associated with development of a new irrigation scheme. Meetings were held with
the following concerned governmental agencies (Annex A [of the Scoping
Statement]):
 Morogoro Regional Administrative Secretary
 Mvomero District Administrative Secretary
 Mvomero District Offices
 Wami-Ruvu Basin Water Office, Morogoro Office
 Morogoro Urban Water and Sewerage Authority
Consultations with government authorities were made through interviews and
discussions.

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In addition, a community meeting was held in the Hembeti Ward on 16 May 2013,
attended by 31 residents from all the villages in the vicinity of the proposed project
(Hembeti, Dihombo, Mkindo, Kigugu and Mbogo). A list of the attendees is
presented in Annex B [of the Scoping Statement].

5 POTENTIAL ISSUES FOR THE PROJECT

This section presents the results of the consultations as well as other issues
identified by the Scoping Statement Team during their review of literature and site
visits.
5.1 Results of Consultations
The meetings with government officials as well as the public meeting at Hembeti
Ward identified several issues for the EA. These are:
 Conflict between farmers and pastoralists over land and water use. This is
a serious issue that has led to physical confrontations, but it is also an
issue that goes beyond the project. Nonetheless, the construction of an
irrigation scheme may exacerbate the problem. That potential needs to be
explored and addressed.
 Loss of grazing land.
 Economic impact of the project.
 Availability of sufficient water in the river to support the project.
 Potential for water quality degradation from the drainage discharge.
 Impacts of fertilizer and pesticide use on water quality, the environment,
livestock and human health.
 Formation of a functioning IO for management of the scheme.
 Loss of a cultivation season during construction.
 Identification and relocation of graves in the project area, prior to
construction.
 Land ownership. “Farm plots are customary owned there is no one with
the official title of plot ownership.”
 Lack of proper land use plan.
5.2 Other Issues
In addition to the issues identified in the previous section, the Scoping Statement
Team identified the following issues for the EA, based on its review of the literature,
field work, and professional judgment.
5.2.1 During Mobilization and Construction
 Displacement of people and economic activities.
 Opportunities for temporary employment.
 Soil erosion from earth moving and materials storage.
 Soil pollution from hazardous substances associated with machinery,
cement mixing and solid waste disposal.

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  Loss of top soil during construction and from field levelling.
 Solid waste generation.
 Water contamination, primarily as a by-product of soil erosion and soil
pollution, but also associated with activities in and near rivers.
 Dust and air pollution from vehicles and equipment.
 Noise pollution from vehicles and equipment.
 Vegetation loss.
 Effects on the terrestrial fauna.
 Effects on aquatic fauna, associated with water quality impacts and
reduced water quantity.
 Health and safety impacts, primarily worker health and safety but also
some issues for community members.
 Change of community lifestyle from impacts of having construction
workers in the community as short-term residents.
5.2.2 During Operation
 Reliable supply of irrigation water and associated increased rice
production.
 Reduced flooding of fields.
 Soil salinity.
 Water logging.
 Water use conflicts.
 Water quantity impacts on downstream users and ecosystems.
 Effects on aquatic fauna, associated with water quality impacts and
reduced water quantity.
 Increase in water related diseases.
 Scheme management capacity.
 WRBWO capacity to control water abstractions.
Table C.1 presents a consolidated list of potential issues.

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Table C.1: Consolidated List of Potential Environmental Issues

Physical Biological Socio-Economic

During Mobilization and Construction

 Soil erosion  Vegetation loss  Opportunities for
 Soil pollution  Effects on the terrestrial temporary employment
 Loss of top soil fauna  Displacement of people
 Effects on aquatic fauna and economic activities
 Solid waste generation
○ Loss of a season of
 Water contamination cattle grazing
 Dust and air pollution ○ Loss of a cultivation
 Noise pollution season
 Worker/community health
and safety
 Change of community
lifestyle

During Operation
 Flooding  Effects on aquatic fauna  Reliable supply of irrigation
 Soil salinity water
 Water logging  Increased rice production
 Water quantity impacts on  Opportunities for
downstream users and employment
ecosystems  Land use conflict –
 Effects of pesticide and cultivation/grazing
fertilizer use  Water use conflicts
 Water contamination  Scheme management
capacity
 WRBWO capacity to
control water abstractions
 Disturbance of graves
 Land ownership
 Lack of proper land use
plan.
 Increase in water related
diseases
 Change of community
lifestyle

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CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME C-4
ANNEX D: MGONGOLA IRRIGATION SCHEME ENVIRONMENTAL
FLOW ASSESSMENT IN THE WAMI RIVER
Environmental flow requirements for the Wami River
The 2013 WRBWO Environmental Flow Assessment (EFA) report (iWASH 2013) provided
an update to the previous 2008 assessment for the Wami River, which developed monthly
flow objectives based on 2007 field work (Sarmett et al. 2008). This second phase of work
included the collection of data during 2011, to provide data for a wetter period and develop a
wider assessment of the hydrology of the catchment. Consideration was given to revisions to
the initially recommended environmental flows from the first round of EFA studies. A holistic
view was taken for the calculation of environmental flows, whereby hydrology,
geomorphology, ecology and water quality have been considered alongside the socio-
economic needs of the local population.
Of the sites assessed by WRBWO, the abstraction for the Mgongola irrigation scheme on
the Mkindo River is located nearest to and upstream from the Wami River at the Mtibwa EFA
site. The reassessment undertaken by WRBWO in 2013 concluded that no change to the
previously reported environmental flows is required from those reported in 2008 at the
Mtibwa site. The dry year environmental flows for the Wami River at the Mtibwa EFA site
from the 2008 and 2013 assessments can be seen below in Table D-1.
Table D.1: Driest Year Recommended Average
Discharge (RAD) at Wami River at the
Mtibwa EFA Site
Driest year RAD
Month Wami River at Mtibwa
March 3.0
April 5.0
May 5.0
June 5.0
July 4.1
Adapted from Table 45 in iWASH (2013)

It should be noted that between the two EFA field investigations in 2008 and 2011, the
original Mtibwa site had been significantly modified by construction of a bridge downstream
and dredging making this site no longer suitable for the EFA study. In 2011, a new site
downstream of the original site was adopted for the EFA.
Water requirements in the context of the 2008 and 2013 EFA
There are no EFA sites on the Mkindo River; therefore, the impact on this river cannot be
assessed. However, the flow from the Mkindo will impact the flow at the Mtibwa EFA site on
the main Wami River. To assess the impact of the abstraction for the irrigation scheme on
the Mtibwa EFA site a number of factors need to be considered, including:
 Flow on the main Wami River at Dakawa gauging station (1G1);
 Flow on the River Mkindo at Mkindo gauging station (1GB2);
 Flow on the Diwale River (1GB1A);
 Other flows (e.g., Dizingwi, Mgongola and Divue rivers)
 Abstraction rates for the Mgongola irrigation scheme;
 Abstraction rates for the Dakawa irrigation scheme;

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  Abstraction rates for the Mtibwa Sugar Estate;
 Abstraction rates for the Dizungu Sugar Estate; and
 Recommended average discharge (RAD) values for the EFA at Mtibwa.

Figure D-1 shows the schematic location and relationship of these factors. Based on data
available it has been assumed that there are no other major abstractions between the
Dakawa gauging station and the Mtibwa EFA site on the Wami River or the gauging stations
and Mtibwa EFA site on the tributaries.
As shown in Figure D-1, the intake site for the existing Mkindo irrigation scheme is upstream
of the Mkindo gauge (1GB2) and the Mtibwa EFA site. Therefore, the gauge records flows
after the existing extraction which has been permitted from 1988 onwards. The Mkindo
River, the source of irrigation water for the proposed Mgongola scheme, flows into the
Diwale River upstream of where the Diwale River joins the main Wami River. The junction of
the Diwale and Wami rivers is upstream of the Mtibwa EFA site.
Flow data
Flow data on the Wami River is available for several years from the Dakawa gauge (1G1).
Sufficient flow data is available to calculate the statistical 1- in 5-year low flows at the
Dakawa gauge (CDM Smith 2013, Annex F).
The Diwale River flows into the Wami River between the Dakawa gauge and the Mtibwa
EFA site as do several small drainages from the south of the Wami River. The Mkindo and
Divue rivers are both perennial and flow into the Diwale River. The Mkindo River is the
major tributary of the Diwale River. The Mkindo River has two tributaries that flow into the
river below the Mkindo gauge, the perennial Dizingwi River and the seasonal Mgongola
River. There are no gauges on Divue, Dizingwi and Mgongola rivers or any of the small
drainages that flow into the Wami River from the south between the Dakawa gauge and the
Mtibwa EFA site, so their flows are not captured in the following analysis.
Flow data on the Mkindo River (1GB2) is available for six years; 1965 to 1969 and
2009/2010. For six years of data, detailed statistical analysis of flow data at Mkindo is not
applicable. Therefore, to adopt a conservative approach the lowest average flow during
each half month period was calculated and the lowest average for the six years of data was
extracted from the record. These values are all lower than the average daily flow (Table D-
2) reported in the EFA (Sarmett et al. 2008), thus conservative values for this assessment as
it considers wet season months.
Table D.2: Catchment and Flow Characteristics at
Diwale and Mkindo Gauging Stations
Mkindo (1GB2) Diwale (1GB1A)
Annual Daily Flow (m3/s) 32.71 9.66
Q70* (m3/s) 10.8 2.8
Area (km2) 90.7 173.8
* Flow will exceed this value 70% of the time
From: Sarmett et al. 2008

For the Diwale River (1GB1A) flow data is available for six years from 1965 to 1970. A
similar approach to that used for the Mkindo River was applied for the Diwale River to
estimate a dry year flow for each half month period during the abstraction period.

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Figure D.1: Schematic of the Diwale/Wami Watershed from the Dakawa Gauge to the Mtibwa EFA Site

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME D-3
Water rights and abstractions
The Mtibwa Sugar Estate, Dakawa irrigation scheme, Mkindo irrigation scheme and
Dizungu Sugar Estate abstract water in the area of interest upstream of the Mtibwa
EFA site. The Mtibwa Sugar Estate has two current water rights. One is for 1.5 m3/s
year-round from the Diwale River below the junction with the Mkindo River18. It uses
this water to irrigate 5,200 ha with sprinklers. The other water right is for 2.5 m3/s
year-round from the Wami River.19 It currently uses this water to irrigate 3,000 ha
with sprinklers on the south side of the Wami River.
Mtibwa Sugar Estate is developing 20,000 ha of new fields on the south side of the
Wami River. By the end of 2014 it had 3,000 ha in production, and plans to add an
additional 3,000 ha by the end of 201620. IRRIP estimates that with completion of the
additional 3,000 ha, the Estate will consume its 2.5 m3/s water right on the Wami
River.
To develop the remaining 14,000 ha of cultivation, the Mtibwa Sugar Estate has
applied for an additional 7.5 m3/s water right from the Wami River.21 The Estate says
it is in the final stages of receiving that right. The right will be restricted to the wet
season, it is not clear how the water right will define “wet season,” but the Estate
says it plans to abstract from March through May or June. This water will be used to
fill two reservoirs with a total capacity of 70 million m3 from which water will be
withdrawn for irrigation during the dry season. The Estate is sure enough that it will
receive the 7.5 m3/s water right that it has invested a significant amount of capital in
the construction of a pump house with 6-pumps on the Wami river.22 Although the
Estate does not have a specific development plan, it is reasonable to assume that
sometime in the next 5 to 10 years it will be abstracting an additional 7.5 m3/s from
the Wami River from March through June, as it will take four months to fill the
reservoirs, if they are doing so at 7.5 m3/s.
The Dakawa irrigation scheme has a water right from the Wami River for 5.0 m3/s
from March through November.23 It currently abstracts 3.5 m3/s but is in the process
of rehabilitating its system and will soon be abstracting from 2.35 to 3.88 m3/s,
depending on the month, at a seasonal average rate of 3.22 m3/s (CDM Smith 2013).
The existing Mkindo irrigation scheme has a water right of 0.624 m3/s and it is
estimated that it currently abstract 0.22 m3/s. The proposed Mgongola irrigation
scheme will require an additional 1.18 m3/s. These abstractions are based on the
assumption of a 2 l/s/ha abstraction rate. If the proposed scheme is constructed, the
two schemes will be managed as one scheme, requiring a total abstraction of 1.4
m3/s and requiring the current water right to be increased by 0.776 m3/s.

18 Water Right Registration Number 4501 of 1980 (WRBWO 2015). Provisional, renewable every three
years.
19 Water Right Registration Number 4959 of 1990 (WRBWO 2015). Provisional, renewable every three
years.
20 From Mtibwe Sugar Estate General Manager at a meeting at the Plantation with IRRIP and Mtibwa
staff on January 27, 2015.
21 Ibid.
22 Located at S6°23’53.0” by E37°38’25.4” and observed and photographed by IRRIP staff on January
27, 2015.
23 Water Right Registration Number 4583 of 2007 (WRBWO 2015). Final (permanent).

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There is no data available on the abstraction for the Dizungu Sugar Estate, which is
an area of approximately 300 ha. It is reported that the Estate does irrigate with
surface water, but no information is available about the abstraction.
Taking all of the above factors into consideration, input-output analysis was
conducted of the impact of the proposed Mgongola scheme on the Mtibwa EFA RAD.
Multiple scenarios were analysed, the results of which indicated that the critical factor
is water use by the Mtibwa Sugar Estate. This report contains two “most likely”
results:
1. Assuming that the Mtibwa Sugar Estate uses only their full, current water
rights (Table D-3), which is the most likely scenario at the end of 2016.
2. Assuming that the Mtibwa Sugar Estate secures and uses an additional water
right of 7.5 m3/s from March through June (Table D-4), which is the most likely
long-term scenario (some time in the next 5 to 10 years).
As can be seen in Tables D-3 and D-4, in the short-term (by the end of 2016), there
will be sufficient water for the Mgongola scheme, but in the longer-term (5 to 10 years
out), water used by the Mtibwa Sugar Estate will consume all of the available water in
two periods (2nd periods of March and June), reducing flows at the Mtibwa EFA site in
two these two periods below the RAD.
To assess the potential impacts on the RAD of other irrigation alternatives, an
analysis was conducted on the irrigation alternative with the least water requirement,
the sprinkling alternative. Assuming that the sprinkling alternative was fully
implemented on the entire 589 ha area, the water requirement would be reduced
from 1.18 to 0.86 m3/s. The results of this analysis are presented in Table D-5. As
with the proposed action, the sprinkler alternative results in reducing the flow at the
Mtibwa EFA site below the RAD in the 2nd periods of March and June.
Climate change scenario
To offer a long-term view of the availability of water at Dakawa, the historic record
has been reviewed to identify any visible decadal trends in flow. As shown in Figure
D-2, no discernible trends are shown in the recorded data.
Figure D.2: Recorded Monthly River Flows at Dakawa 1953-1983

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Table D.3 Low-flow Residual Flows (m3/s) in Relation to the RAD at Mtibwa EFA Site, End of 2016 Scenario
(a) (b) (c) (d) (e) (f) (g) (c+d+e-a-
Sugar Mkindo 1-in-5 yr Dakawa 2000 Mgongola f-g)
Estate Irrigation flow Low flow Low flow ha Scheme Scheme Residual Driest Over or
Water Water Dakawa at on Pump Additional Flow year RAD Under
Period Use* Use** Gauge Mkindo** Diwale** Requirement Water use at Mtibwa at Mtibwa RAD
March 2 4.00 0.22 10.8 2.5 1.3 3.42 1.18 6.0 3.0 3.0
April 1 4.00 0.22 19.7 8.3 7.2 2.71 1.18 27.3 5.0 22.3
2 4.00 0.22 32.6 9.9 12.4 3.45 1.18 46.3 5.0 41.3
May 1 4.00 0.22 39.0 6.5 8.5 3.48 1.18 45.3 5.0 40.3
2 4.00 0.22 25.4 5.9 8.4 3.79 1.18 30.7 5.0 25.7
June 1 4.00 0.22 14.5 4.8 6.0 3.88 1.18 16.2 5.0 11.2
2 4.00 0.22 11.9 3.1 2.7 3.14 1.18 9.4 5.0 4.4
July 1 4.00 0.22 9.2 2.4 2.0 2.76 1.18 5.7 4.1 1.6
2 4.00 0.22 9.0 2.1 3.2 2.35 1.18 6.7 4.1 2.6
Notes:
* Full use of current water rights on 11,000 ha of sugar.
** For information purposes only, as the abstraction for Mkindo Irrigation is above the Mkindo gauge, so it is already accounted for in the Mkindo flow data.
† Assumes lowest average flow in half month period for Mkindu and Diwale based on 6 years of gauge data at each station.

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Table D.4: Low-flow Residual Flows (m3/s) in Relation to the RAD at Mtibwa EFA Site, 5 to 10 Years in Future Scenario
Sugar Mkindo 1-in-5 yr Dakawa 2000 Mgongola
Estate Irrigation Flow Low Flow Low Flow ha Scheme Scheme Residual Driest Over or
Water Water Dakawa Mkindo Diwale Pump Additional Flow year RAD Under
Period Use* Use** Gauge Gauge† Gauge† Requirement Water Use at Mtibwa at Mtibwa RAD
March 2 11.50 0.22 10.8 2.5 1.3 3.42 1.18 -1.5 3.0 -4.5
April 1 11.50 0.22 19.7 8.3 7.2 2.71 1.18 19.8 5.0 14.8
2 11.50 0.22 32.6 9.9 12.4 3.45 1.18 38.8 5.0 33.8
May 1 11.50 0.22 39.0 6.5 8.5 3.48 1.18 37.8 5.0 32.8
2 11.50 0.22 25.4 5.9 8.4 3.79 1.18 23.2 5.0 18.2
June 1 11.50 0.22 14.5 4.8 6.0 3.88 1.18 8.7 5.0 3.7
2 11.50 0.22 11.9 3.1 2.7 3.14 1.18 1.9 5.0 -3.1
July 1 4.00 0.22 9.2 2.4 2.0 2.76 1.18 5.7 4.1 1.6
2 4.00 0.22 9.0 2.1 3.2 2.35 1.18 6.7 4.1 2.6
Notes:
* From Mtibwa Sugar Estate General Manager at a meeting at the Plantation with IRRIP staff on January 27, 2015.
** For information purposes only, as the abstraction for Mkindo Irrigation is above the Mkindo gauge, so it is already accounted for in the Mkindo flow data.
† Assumes lowest average flow in half month period for Mkindu and Diwale based on 6 years of gauge data at each station.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME D-7
Table D.5: Low-flow Residual Flows (m3/s) in Relation to the RAD at Mtibwa EFA Site with Sprinkler Irrigation, Current Abstractions
Scenario
Sugar Mkindo 1-in-5 yr Dakawa 2000 Mgongola
Estate Irrigation Flow Low Flow Low Flow ha Scheme Scheme Residual Driest Over or
Water Water Dakawa Mkindo Diwale Pump Additional Flow year RAD Under
Period Use* Use** Gauge Gauge† Gauge† Requirement Water Use at Mtibwa at Mtibwa RAD
March 2 11.50 0.22 10.8 2.5 1.3 3.42 0.86 -1.2 3.0 -4.2
April 1 11.50 0.22 19.7 8.3 7.2 2.71 0.86 20.1 5.0 15.1
2 11.50 0.22 32.6 9.9 12.4 3.45 0.86 39.1 5.0 34.1
May 1 11.50 0.22 39.0 6.5 8.5 3.48 0.86 38.1 5.0 33.1
2 11.50 0.22 25.4 5.9 8.4 3.79 0.86 23.5 5.0 18.5
June 1 11.50 0.22 14.5 4.8 6.0 3.88 0.86 9.0 5.0 4.0
2 11.50 0.22 11.9 3.1 2.7 3.14 0.86 2.2 5.0 -2.8
July 1 4.00 0.22 9.2 2.4 2.0 2.76 0.86 6.0 4.1 1.9
2 4.00 0.22 9.0 2.1 3.2 2.35 0.86 7.0 4.1 2.9
* From Mtibwa Sugar Estate General Manager at a meeting at the Plantation with IRRIP staff on January 27, 2015.
** For information purposes only, as the abstraction for Mkindo Irrigation is above the Mkindo gauge, so it is already accounted for in the Mkindo flow data.
† Assumes lowest average flow in half month period for Mkindu and Diwale based on 6 years of gauge data at each station.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME D-8
In the absence of site-specific climate change data, a general assessment of the
sensitivity of environmental flow compliance can be made by assuming a 10%
reduction in river flows as a result of climate change. This constitutes a conservative
assessment for a 30 year period particularly during the wet season where the latest
climate change reports for Tanzania suggest that rainfall is likely to increase
(McSweeney et al. 2012). The results of this analysis showed that the negative
impact on the RAD occurred in the same periods, but were greater in magnitude.
Conclusions
Under current conditions and in the short-term future (end of 2016), proposed action
and all other irrigation alternatives for the Mgongola scheme will result in flows above
the RAD at the Mtibwa EFA site. But as the Mtibwa Sugar Estate brings on its
additional water rights, which appears to be inevitable, the RAD will not be met
during 2 of the 9 semi-monthly periods (2nd periods of March and June) of the
irrigation season for the Mgongola scheme.
This analysis does not include flows from Divue, Dizingwi and Mgongola rivers or any
of the small drainages that flow into the Wami River from the south between the
Dakawa gauge and the Mtibwa EFA site. No data is available for these water
sources. However, it is unlikely that these flows would offset the RAD deficits as
these rivers are minor (and at least in one case intermittent) and they would have to
have a combined flow equal to the gauged flow in the Mkindo River in the 2nd period
of June, and 18% greater than the combined gauged flow of the Diwale and Mkindo
rivers in the 2nd period of March. Neither of these are reasonable assumptions.

Citations
CDM Smith. 2013. Draft Environmental Assessment, Rehabilitation of Dakawa
Irrigation Scheme. IRRIP1, for USAID/Tanzania. 4 December 2013. 105pp.
iWASH. 2013. Climate in the Wami and Ruvu Basins, Tanzania: Current
Characteristics and Future Projections. Draft interim report. Tanzania
Integrated Water, Sanitation and Hygiene (iWASH) Program, September
2013. 68pp.
McSweeney, C., M. New and G. Lizcano. 2012. UNDP Climate Change Country
Profiles: Tanzania. 27 pp. Available: http://country-profiles.geog.ox.ac.uk/
[Accessed 29 January 2015].
Sarmett, Julius, Elizabeth Anderson and Appa Mandari. 2008. Wami River Sub-
Basin, Tanzania: Initial Environmental Flow Assessment. Wami-Ruvu Basin
Water Office, Global Water for Sustainability Program, Florida International
University, and Water Development Alliance. Synthesis Report, June 2008.
151pp. http://pdf.usaid.gov/pdf_docs/pnads254.pdf accessed on 13
November 2013.
Wami/Ruvu Basin Water Office (WRBWO). 2015. Report on Water Use in Wami
Subcatchment. 23 January 2015. 6 pp.

ENVIRONMENTAL ASSESSMENT
CONSTRUCTION OF MGONGOLA IRRIGATION SCHEME D-9
 Engineering Services for the Tanzania
Irrigation and Rural Roads Infrastructure Project (IRRIP1)

U.S. Agency for International Development

686 Old Bagamoyo Road, Msasani
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