MODULE

INTEGRATED WATER RESOURCES MANAGEMENT

AND THE GROUNDWATER MANAGEMENT FRAMEWORK

INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

2 INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA
 MODULE

CONTENT 2

Integrated Water Resources

MODULE 2 Management and the

Groundwater Management
Framework
Integrated Water Resources Management and the Groundwater Management
Framework
2.1 Introduction 4
2.2 Groundwater in the hydrologic cycle 5
2.3 Characteristics of groundwater 7
2.4 Sustainable groundwater use 9
2.5 What is Integrated Water Resources Management (IWRM)? 10
2.6 IWRM principles and framework 10
2.7 Groundwater management for river basins 13
2.8 Summary 18
2.9 References 18
2.10 Exercise 19

Imprint
© Copyright 2015, all rights reserved
The use of the manual is FREE of cost. AGW-Net simply requests that users give proper
attribution “Integration of Groundwater Management into Transboundary Basin Organizations in
Africa - a Training Manual by AGW-Net, BGR, IWMI, CapNet, ANBO, & IGRAC” . Modification is
only allowed with permission of AGW-Net.
Photos are copyright to their respective owners.

■■ A4A – Aqua for All

■■ AGW-Net – Africa Groundwater Network
■■ ANBO – African Network of Basin Organisations
■■ BGR – Bundesanstalt für Geowissenschaften und Rohstoffe
■■ BMZ – Federal Ministry for Economic Cooperation and Development
■■ GWP – Global Water Partnership
■■ IGRAC – International Groundwater Resources Assessment Centre
■■ imawesa – Improved Management of Agricultural Water in Eastern and
Southern Africa
■■ IWMI – International Water Management Institute
■■ UNDP-CapNet – United Nations Development Programme Capacity Development
Network in Sustainable Water Management

Editorial Staff: Vanessa Vaessen, Ramon Brentführer – BGR

Layout: ff.mediengestaltung GmbH, Hannover, Germany
Picture: IWMI

Implemented by:

INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA 3

MODULE

2
INTEGRATED WATER RESOURCES MANAGEMENT
Integrated Water Resources
AND THE GROUNDWATER MANAGEMENT
Management and the
Groundwater Management
FRAMEWORK
Framework

LEARNING OBJECTIVES
This module emphasises the need for managing groundwater in the context of
Integrated Water Resources Management. The module will contribute to the
following learning objectives:

■■ Appreciate the characteristics of groundwater in the context of all available

freshwater resources
■■ Understand the challenges facing groundwater management and the need for
improved approaches to address the resource management problems
■■ Understand key principles and themes in IWRM with respect to joint sur-
face-groundwater management
■■ Emphasize key advantages of incorporating groundwater management into
national and river basin water resource planning

2.1 Introduction
One of the cornerstones of the IWRM philosophy is that the fundamental management
unit for water should be a ‘river basin’ or ‘surface water catchment’. A river basin is
a naturally occurring physical entity that has a contiguous integrated surface water
system with a unique outlet. Water management by river basin is therefore based on
physical ecological reality. Due to this guiding philosophy, many nations now manage
their water by river basin, and many River Basin Organizations (RBOs) and other
catchment water management authorities have been created.

The conjunctive management of groundwater and surface water is also a guiding prin-
ciple of IWRM. However the integrated management of surface and groundwater has
lagged behind in many RBOs for various reasons. These include traditional institution-
al separation of groundwater and surface water management, the different knowledge
and skill systems required for surface and groundwater management, and the fact that
aquifer systems may not coincide with river basin boundaries. Aquifers may be trans-
boundary between adjacent river basins, and / or shared between two or more states.
(See Module 4: Management of transboundary aquifers)

Given their overarching prominence in regional transboundary water management in

Africa, RBOs have a unique opportunity to fully integrate groundwater and surface
water management and thereby manage their catchment water supplies in an optimal
and sustainable manner.

A fundamental purpose of this short course is to promote this objective by providing

an overall understanding of groundwater management within IWRM and by providing
tools for river basin water managers to manage their groundwater resources conjunc-
tively with their surface water resources.

4 INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

 MODULE

2.2 Groundwater in the hydrologic cycle 2

■■ The hydrologic cycle is the continuous circular process by which water evaporates from the
oceans, condenses and falls to the Earth as rain or snow, becomes run-off and ground- Integrated Water Resources
Management and the
water recharge and eventually returns to the oceans through river flow and groundwater Groundwater Management
Framework
discharge. (Figure 2.1).
■■ The implications of the hydrologic cycle are that surface water and groundwater cannot be
sustainably managed separately since they are inextricably bound together in the water
cycle.

Figure 2.1 Hydrologic cycle: linkages between surface and groundwater.

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MODULE

2
Importance of groundwater
■■ Although groundwater is the hidden part of the hydrologic cycle, it represents a
Integrated Water Resources much larger volume than surface water. Groundwater makes up 97% of the availa-
Management and the
Groundwater Management ble unfrozen freshwater on our planet (Figure 2.2)
Framework
■■ The surface water / groundwater ratio in Africa is similar (Fig 2.3), with groundwa-
ter at (5,500,000 km3) dominating the available freshwater resources (31,776 km3).
■■ Africa is blessed with abundant groundwater resources, although perversely most
of the largest aquifers are located either in the humid and water rich Congo basin
or in the sparsely populated Sahara / Sahel areas (Fig 2.4)
■■ Groundwater is the main source of water for domestic use for more than 2 billion
people in the world – that is almost 30% of the estimated 7 billion global popula-
tion. It is often the only source of water for all uses for dispersed rural communities
in semi-arid regions
■■ The accelerated global development over the past few decades has been signif-
icantly supported by groundwater, as a low-cost, drought-resistant and (mainly)
high-quality water supply for urban and rural populations and for irrigation (Module
9: Groundwater for food production.)
■■ It is the major source of water for many mega cities (Mexico City, Dhaka, Dar es
Salaam, etc.)
■■ Groundwater is under-developed in many parts of the continent
■■ Additional and sustainable use of groundwater will be vital for the achievement
of the ‘UN Sustainable Development Goals’ and for adaptation to climate change
(Module 11: Groundwater and Climate Change)

Figure 2.2 Distribution of earth’s freshwater resources

6 INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

 MODULE

Integrated Water Resources

Management and the
Groundwater Management
Framework

Figure 2.3 Regional distribution of global groundwater resources.

Source: UNEP, 2008. http://www.unep.org/dewa/vitalwater/article32.html

2.3 Characteristics of groundwater

Besides its importance in terms of quantity, groundwater has a number of other
natural and physical characteristics that makes it an important resource for eco-
nomic and social development. (Table 2.1)

However although groundwater has many positive characteristics, there are

some critical issues that make groundwater management complex and difficult
■■ Groundwater is invisible and often there is very limited data available on its physi-
cal distribution and aquifer characteristics
■■ Groundwater flow within the aquifer systems is difficult to ascertain and can vary
over time due to pumping, natural discharge and recharge, climate change, etc.
■■ There are usually many independent users pumping groundwater, thus making
monitoring abstraction and managing users complicated
■■ The interaction between surface water and groundwater is often little understood
but can have great implications for management decisions

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MODULE

Integrated Water Resources

Management and the
Groundwater Management
Framework

Figure 2.4 Aquifer productivity map of Africa. Source: British Geological Survey, 2011.
http://www.bgs.ac.uk/research/groundwater/international/africangroundwater/mapsDownload.html

Table 2.1 Beneficial characteristics of groundwater resources

Characteristics Explanation
Available where Groundwater can be found almost everywhere (not neccesarily in the quantities desired)
needed
Naturally Groundwater is protected against direct pollution and evaporation, and often provides
protected potable water without treatment
Our largest Global groundwater storage is vast, providing a water buffer that can be used to
reservoir mitigate droughts and water scarcity
Untapped There are many untapped aquifers that can provide water for future needs if managed
resource sustainably. This is particularly true in Africa (e.g. Addis Ababa and Dar es Salaam)
Stable Groundwater is becoming increasingly used as an important and safe source of
temperature renewable energy for heating and cooling, although this use is still minor in Africa.
Environmental Dry season river baseflow is maintained by groundwater discharge. Groundwater
function dependent ecosystems (GDE) such as wetlands provide vital environmental services.
Natural Soils and aquifers have the capacity to improve water quality by degradation and
treatment sorption of biological and some chemical contaminants.

8 INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

 MODULE

2.4 Sustainable groundwater use 2

Worldwide, sustainable water resources development and management is rec-
ognized as an ultimate goal of national water strategies. The sustainability of Integrated Water Resources
Management and the
groundwater is closely linked with a range of micro- and macro-policy issues in- Groundwater Management
Framework
fluencing water and land use, and represents one of the major global challenges
in natural resource management.

Whilst groundwater storage is vast (more than 97% of freshwater reserves) its replen-
ishment by recharge is finite and mainly limited to shallower aquifers, which can also
be seriously degraded by pollution. Groundwater is the invisible part of the hydrologic
cycle and a clear understanding of its physical environment in space and time (qual-
ity, depth, recharge, productivity) is required to take decisions on cost-effective and
sustainable exploitation (Module 3: Aquifer systems characterization for groundwater
management). However such information about groundwater is not routinely obtained
in most countries.

Investment in the assessment, management and protection of the resource base

has been seriously neglected. Practical advances are urgently needed; there is no
simple blueprint for action, due to the inherent variability of groundwater systems and
related socioeconomic situations. Many developing nations need to appreciate their
socio-economic dependency on groundwater, and invest in strengthening institutional
provisions and building institutional capacity for its improved management before it is
too late.

For example, in Harare (2014), the water distribution network based on surface water
and the water treatment plant, due to aging, lack of investment and lack of mainte-
nance, lacks the capacity to serve the needs of the expanding population. Water sup-
plies are erratic, insufficient and have not reached some parts of the city for several
years. The result has been an explosion of borehole drilling, mushrooming of bulk
water sellers, and uncontrolled private pumping of groundwater, particularly in parts of
the city where people can afford private boreholes. Over the past decade, groundwa-
ter levels have declined by more than 10 m and many boreholes have already dried
up. Water level and compliance monitoring are hampered by lack of investment into
the catchment authorities, and the situation continues to deteriorate. Many other cities
in Africa face similar problems, e.g. Lusaka, Accra, Nairobi.

Traditional institutional separation of surface water from groundwater has created

fundamental communication barriers that now extend from technical experts to policy
developers, operational managers and water users (Module 7: The role of stakeholder
participation and communication in groundwater management). These barriers impede
the understanding of the processes and consequences of groundwater-surface water
interactions.

INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA 9

MODULE

2
Ultimately sustainable groundwater use requires a comprehensive understand-
ing of the multiple factors that impact on the resource. These may include:
Integrated Water Resources ■■ The impact of land use / land management which has a direct impact on both
Management and the
Groundwater Management groundwater recharge and on groundwater pollution.
Framework
■■ The protection of the groundwater resource though separation of important water
supply wells and groundwater recharge areas from polluting activities such as
waste disposal sites, sewage treatment plants etc.
■■ In water scarce areas, managed aquifer recharge (MAR), from e.g. occasional
flood waters or irrigation excess water, can be introduced to promote sustainability
of the groundwater resource
■■ In all circumstances where possible, conjunctive use of surface and groundwater
can be used to ensure the optimum sustainable use of the total water resource.

2.5 What is IWRM?

Integrated Water Resources Management (IWRM) is an approach that promotes the
coordinated development and management of water, land, and related resources, in
order to maximize the resultant economic and social welfare in an equitable manner
without compromising the sustainability of vital ecosystems.

IWRM is not just about managing physical resources, it is also about reforming human
systems to enable people, women as well as men, to benefit from those resources and
to protect and manage them. Integrated water resources management is a compre-
hensive process for the sustainable development, allocation and monitoring of water
resources and their use in the context of social, economic and environmental objec-
tives. The integration of groundwater into the IWRM paradigm can provide important
benefits for both the water managers and the societies that they serve.

2.6 IWRM principles and framework

There are three key ‘pillars’ that provide a framework for the implementation of IWRM
(Figure 2.5). These are: economic efficiency; environmental sustainability; and social
equity. All IWRM plans need to operate with these three fundamental objectives in
mind.

Ecosystem Sustainability

Enabling
Environment
ts
en In
m st
tru itu
ns tio
tI Aquifer & n R
en ol
e m Assessment Policy River Basin es
ag
an Information Legislation Central-Local
M Allocation tools Regulation Public-private

Social Equity

Figure 2.5 The IWRM Implementation Triangle

10 INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

 MODULE

To enhance IWRM, there are three key areas for IWRM reforms: 2
■■ Enabling Environment – water policy; water laws and regulations; financial and
economic instruments (Module 6: Groundwater regulation, licensing, allocation Integrated Water Resources
Management and the
and institutions) Groundwater Management
Framework
■■ Institutional Roles – organizational frameworks; institutional capacity development
■■ Management Instruments – assessment and monitoring of (ground)water re-
sources; water demand information; allocation tools, predictive models (Module 5:
Groundwater Monitoring and Information Management).

These three action areas are known to be essential for implementing IWRM and are
presently driving country level reform at all stages in water planning and manage-
ment in Africa. This usually begins with a new water policy to reflect the principles of
sustainable management. To put the policy into practice requires the reform of water
law and water institutions. This can be a long process and needs to involve extensive
consultations with affected agencies and the public.

Implementation of IWRM is best done in a step-by-step iterative process, with some

changes taking place immediately and others requiring several years of planning and
capacity building.

When beginning the process of change, consider:

■■ What changes must happen to achieve agreed-upon goals?
■■ Where and when is change possible given the current social, political, economic
and institutional situation?
■■ What is the logical sequence for change? What changes need to come first to
make other changes possible?

When considering how water should be managed in the future, the various areas for
change available to the planners are identified in the Tool Box in table 2.2

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MODULE

2
Table 2.2: IWRM Tool Box: Change Areas (http://www.gwp.org/en/ToolBox/)

Integrated Water Resources

Management and the
Groundwater Management THE THIRTEEN KEY IWRM CHANGE AREAS
Framework

THE ENABLING ENVIRONMENT

1. Policies – setting goals for water use, protection and conservation.
2. Legislative framework – the rules to enforce to achieve policies and goals.
3. Financing and incentive structures – allocating financial resources to meet water
needs.
INSTITUTIONAL ROLES
4. Creating an organizational framework – forms and functions.
5. Institutional capacity building – developing human resources.
MANAGEMENT INSTRUMENTS
6. Water resources assessment – understanding resources and needs.
7. Plans for IWRM – combining development options, resource use and human interac-
tion.
8. Demand management – using water more efficiently.
9. Social change instruments – encouraging a water-oriented civil society.
10. Conflict resolution – managing disputes, ensuring sharing of water.
11. Regulatory instruments – allocation and water use limits.
12. Economic instruments – using value and prices for efficiency and equity.
13. Information management and exchange– improving knowledge for better water
management.

There are many courses and manuals (IWRM for River Basin Organizations; IWRM
Plans, etc. at www.cap-net.org) that expand on the principles and implementation
of IWRM more broadly. This manual focuses on the specific issues associated with
groundwater management for basin organizations.

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 MODULE

2.7 Groundwater management for river basins 2

Although the principles of IWRM emphasize that groundwater and surface water
must be managed as a single resource, how to achieve this may not be imme- Integrated Water Resources
Management and the
diately obvious to RBO professional and technical staff, who tend to be more Groundwater Management
Framework
skilled in managing surface waters. There are certain distinct features about
groundwater that water managers need to take into account in order to achieve
an optimum level of conjunctive management of surface and groundwater.

Table 2.3 Comperative features of groundwater and surface water

Feature Groundwater Surface Water

Resources & Aquifers Resources & Reservoirs
Hydrological Characteristics
Storage Very large Small to moderate
Resource Areas Relativity unrestricted Restricted to water bodies
Recharge Restricted to unconfined Takes place everywhere with
aquifers rainfall
Response to changes Very slow Rapid
Flow velocities Low Moderate to high
Residence time Generally decades / centuries Mainly weeks / months
Drought vulnerability Generally low Generally high
Evaporation losses Low and localised High for reservoirs
Resource evaluation High cost and significant Lower cost and often less
uncertainty uncertainty
Abstraction impacts Delayed and dispersed Immediate
Natural quality Generally (but not always) high Variable
Pollution vulnerability Variable natural protection Largely unprotected
Pollution persistent Often extreme Mainly transitory

Socio-Economic Factors
Public perception of the Mythical, unpredictable Aesthetic, predictable
resource
Development cost Generally modest Often high
Development risk Less than often perceived More than often assumed
Style of development Mixed public and private, often Largely public
by individuals

Table 2.3 compares the hydrological characteristics of groundwater and surface water
as well as the socio-economic factors that are important in terms of management and
provide insight into how management strategies may be adjusted when managing
groundwater resources.

While no specific ‘toolbox’ for groundwater management in river basins has been
created, water resources managers will find that as their understanding of the ground-
water resource grows, their appreciation of how groundwater can be integrated into
river basin water resources management will increase too. The aim is to conjunctively
manage surface and groundwater for optimum sustainable water resources manage-
ment.

A focus on conjunctive management will require that the basin authority develops
capacity in groundwater management. Groundwater management often entails signif-

INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA 13

MODULE

2
icant uncertainty, for example in the extent of the resource, the recharge rate and the
discharge and abstraction. These complexities require an adequate level of profes-
Integrated Water Resources sional groundwater skill to be retained in-house by the basin authority.
Management and the
Groundwater Management
Framework
A key issue for sustainable groundwater management is balancing the increas-
ing demands of water users with the available resources by:
a. balancing groundwater abstraction against long term average annual groundwater
recharge
b. protecting groundwater from all forms of pollution, but especially from pollution by
persistent toxic chemicals

A schematized illustration of sustainable management of the groundwater balance is

shown in Fig 2.6. This supply vs. demand illustration captures all sources of supply
from both recharge and from storage as well as considering the range of demand for
groundwater including subsistence, economic and environmental demands.

Although figure 2.6 focuses on groundwater management, the direct interaction

between surface water and groundwater is a critical reason to manage these
resources conjunctively. Some of the direct interactions are given below:
■■ Groundwater recharge is impacted by surface water use. Damming rivers and
abstracting water reduces downstream flow for indirect groundwater recharge
through riverbed infiltration. This is often the major component of groundwater
recharge in arid and semi-arid environments. Irrigation excess and wastewater dis-
charge are also sources of groundwater recharge.
■■ Similarly groundwater use, particularly from shallow unconfined aquifers, delays
the timing and reduces the amount of surface run-off in the rainy season and de-
creases baseflow in the dry season. Such baseflow may be of critical importance
especially during the periods of low flow and in semi-arid climates.
■■ Groundwater may provide perennial water to groundwater dependent ecosystems
and the communities that survive from these resources.
■■ Interaction between surface water and groundwater can cause pollution to be
transferred from one to the other. Groundwater pollution can persist for centuries
thereby reducing water resources availability for generations to come.

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2
Natural recharge Indirect recharge
(irrigation losses, (excess rainfall, (aquitared leakage, cross
Integrated Water Resources
wastewater returns) surface water seepage) Management and the
Groundwater Management
Framework

Aquifer storage
(groundwater resource)

SUSTAINABLE GROUNDWATER DEVELOPMENT

Economic benefits Environmental benefits Human benefits

Water for the

Water for people
Water for development environment
groundwater supply
groundwater abstractiob groundwater discharge
(drinking water
(agriculture & industry) (springs, surface water,
& sanitation)
wetlands, coastal zone)

Figure 2.6 The elements of sustainable groundwater management:

supply (above) and demand (below)

Once RBO water managers embrace the groundwater resource as a component of

their available water resources and part of their management responsibilities, they
soon begin to appreciate the opportunities and advantages of conjunctive manage-
ment strategies. Examples of opportunities for conjunctive management may include:
■■ Groundwater holds large volumes of water in storage, while surface water storage
is moderate or small and often ephemeral. A conjunctive management strategy
suggests to allocate surface water ressources before running off and evaporating.
In contrast groundwater use should be increased in the dry season to offset the
shortfall from surface water. Groundwater resources provide a buffer in times of
drought and water scarcity.
■■ Managed aquifer recharge (MAR) of sandy aquifers may be done with surplus
surface water during the wet season if there is excess flow. Recharging aquifers
in this way will not only provide additional dry season water resources but will also
allow for natural purification of any bacterial contamination in the surface water.
■■ Groundwater may be developed where demand is dispersed and moderate, while
development of surface water may focus on large-scale demand and irrigation
development.
■■ Upstream and downstream interests: by considering the entire suite of water re-
sources, both surface and groundwater, along the length of a catchment, manag-
ers are better able to provide for equitable upstream and downstream demands.

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MODULE

2
■■ Financing of groundwater development is a key area for flexibility. In many instanc-
es, private and individual development of the resource takes place, particularly if
Integrated Water Resources the basin authority establishes a positive enabling environment such as, for exam-
Management and the
Groundwater Management ple, subsidies for electricity or borehole drilling.
Framework
■■ Public development of groundwater may be incremental as demand rises, thus
avoiding high financing charges and interest payments. The funds saved can
provide the basin authority with financial flexibility to manage its expenditure for
surface water infrastructure and other development in an optimal manner.
■■ Many sectors depend on water: agriculture, energy, water supply, and environ-
ment. By integrating the entire suite of available water resources, water managers
are better able to balance the different competing needs in the catchment.

Water resources management includes many opportunities and threats. The wise wa-
ter manager looks beyond the obvious and acts prospective in order to enhance and
protect the catchment water resources. Some of these issues are listed below:
■■ Land and water. Land management plays a fundamental role in a number of
groundwater related factors such as recharge and non-point source pollution, as
well as being linked to baseflow, overland flow and run-off.
■■ The river basin and its adjacent coastal and marine environment. The salinization
of coastal groundwater resources has become a major issue for many coastal
cities. Overpumping of coastal aquifers is the major cause of this.
■■ Rural water supply. Groundwater may often be used as a potable source of water
without treatment, providing water managers with useful options for dispersed
smaller communities.
■■ Groundwater pollution. Polluted groundwater may take a very long time to reme-
diate, and precautionary protection from pollution is strongly recommended. This
may include oversight of waste management practices in the catchment. (Module
8: Groundwater hazards)
■■ Groundwater often developed privately. Unlike surface water which is usually
developed and managed by an external authority, groundwater may be developed
by users for their own needs. This requires a different management paradigm to
ensure the sustainability and protection of groundwater resources. (Module 7: The
role of stakeholder participation and communication in groundwater management)
■■ Water as a free human right and a chargeable, tradeable commodity or service.
Groundwater resources may be traded just as surface water is, but knowledge
is needed about the impact of groundwater abstraction when engaging in such
transactions.

These examples and other conjunctive use strategies provide the basin authority,
whether transboundary or not, with a variety of diverse challenges but also significant
flexibility for water management under a variety of climatic and socio-economic chal-
lenges.

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 MODULE

Table 2.4 suggests that the approach taken to groundwater management at any 2
moment in time will depend on information about, and interaction between, the
following factors: Integrated Water Resources
Management and the
■■ The depth, size and complexity of the groundwater resource Groundwater Management
Framework
■■ The climate and the rate of aquifer recharge and resource renewal
■■ The scale of groundwater abstraction and the number and types of groundwater
users
■■ The ecosytems and environmental services dependent upon groundwater (Module
10: Groundwater and environment)
■■ The susceptibility and vulnerability of the aquifer system to degradation (Module 8:
Groundwater hazards)
■■ Natural groundwater quality concerns
■■ Present degradation of the groundwater resource (from depletion or pollution)
■■ Other available water resources

Table 2.4 Typical aquifer types and their appropriate management strategies

Hydrogeological Setting Main Feature Recommendation African Examples

Significant aquifers but with Specific aquifer units or Plans need to take into Stampreit aquifer.
more limited extension than groundwater bodies will require account that groundwater Orange-Senqu river basin.
the river basin catchment independent local management recharge may be dependent South Africa, Namibia,
plans upon upstream river flow and Botswana.
downstream river flow may
be dependent upon aquifer
discharge
River basins extensively Management of surface water Fully integrated ground The Limpopo River alluvials
underlain by shallow and groundwater interactions and surface water resource Limpopo basin.
aquifers are critical to avoid problems planning and management is Botswana, South Africa,
such as salt mobilization on essential Zimbabwe Mozambique
land clearance, water logging,
salinization from irrigated
agriculture
Extensive deep aquifer Groundwater flow system It may not be helpful to Nubian Sandstone
systems occurring in arid dominates, there is little establish a ‘river basin Libya, Egypt, Sudan.
regions permanent surface water organization’, but more valid to Nile Basin
define a groundwater resource
management plan and to
manage at ‘aquifer level’
Minor aquifers predominant, Such aquifer systems occur Storage not sufficient to Crystalline basement aquifers
characterized by shallow in many parts of the Sub- justify comprehensive in eg: Tanzania, Ghana,
depth, patchy distribution Sahara African continental groundwater resource planning Zambia etc.
and low potential shield – these will have limited and administration. Social
interaction with the overlying importance in rural water
river basin supply makes it appropriate to
put effort into design of water-
wells to maximize their yield
and reliability, and to identify
any geogenic groundwater
quality problems
Transboundary aquifers May be of different types; Need to assess the degree of Kalahari aquifer: Zambezi /
local or extensive. Requires transboundary interaction and Limpopo basins.
legal and political oversight the strategies required Zambia, Botswana Zimbabwe

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MODULE

2
2.8 Summary
Groundwater management for river basin organizations is essential as part of IWRM
Integrated Water Resources to ensure the long-term sustainability of the overall basin water resources and to
Management and the
Groundwater Management optimize the water use in the basin by conjunctive management of the surface and
Framework
groundwater resources and associated land uses. The importance and potential
benefits of such management become clearer as water scarcity and groundwater
quality degradation increases. Transboundary aquifer systems are a special case that
requires a political and legal framework as well as transboundary institutional cooper-
ation.

Important questions that water managers may ask themselves are:

■■ What is the RBO already doing on GW management?
■■ What they see as the most important GW management issues to take up next?
■■ Why (political, technical economic, social reasons) do you consider these to be the
most important next steps?

2.9 References
GWMate, 2004.
Briefing Note 0: Series Overview.
http://water.worldbank.org/node/83769.

GWMate, 2004.
Briefing Note 1: Groundwater Resources Management.
http://water.worldbank.org/node/83769.

GWP ToolBox C2.03.

http://www.gwptoolbox.org/index.php?option=com_tool&id=30

Cap-Net, 2005.
Integrated Water Resources Management Plans.
http://cap-net.org/node/1515

GWMate, 2004.
Briefing Note 15: Groundwater Dependent Ecosystems.
http://water.worldbank.org/node/83769.

Cap-Net, 2008.
Integrated Water Resources Management for River Basin Organzations.
http://cap-net.org/node/1494

GWP, 2004.
Catalysing Change Handbook.
http://www.gwp.org/en/ToolBox/PUBLICATIONS/Catalyzing-Change-Handbook1/

18 INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

 EXERCICE

2.10 Exercise 2

Limpopo transboundary basin Integrated Water Resources

Management and the
Alluvial aquifers and large-scale irrigation along the banks of the Limpopo Groundwater Management
River. Framework

* Answers are in red

The Issues: The Limpopo River is an international river and the Limpopo Basin Com- and must be removed
mission (LIMCOM), a transboundary basin organization, manages the water flows. before providing
exercise to course
River flows are gauged at a number of gauging stations and weirs along the main participants.
stem of the Limpopo River and also along some of the major tributaries.

Just upstream of the towns of Messina and Beit Bridge (Figure 1 – Map / Satellite
image of area), there is large-scale commercial irrigation development, growing prin-
cipally citrus and cotton, on both the South African and the Zimbabwean sides of the
stream (figure 2).

A total area of 6500 ha are irrigated from alluvial groundwater. Assume an irrigation
demand of 1 litre/sec per ha. continuously for 300 days per year. The 65 days without
irrigation occur between December and February during the rainy season. Assume
that the irrigation water is pumped from the alluvial sands in the active river channel,
and that this water is at the expense of river flow. Table 1 provides a water balance
data and figure 3 is a graphic chart that shows the water balance components. River
flow blue line is the Limpopo flow prior to irrigation development. Assume that the allu-
vial aquifer must be fully recharged before the onset of any surface flow.

What is the delay (months) in the onset of surface flow at the start of the annual hydro-
logical year due to the irrigation? 3 months.
Identify the months during which aquifer recharge takes place. Dec, Jan, Feb
In which month does the aquifer first become fully saturated? Jan
In which month does river flow start again? and in which month does river flow end?
Jan and Feb
How many months earlier will surface flow in the Limpopo end at the end of the rainy
season due to the irrigation? 6 months
What is the difference between river flow without groundwater abstraction and river
flow with groundwater abstraction? 63.4 m³/s

■■ Draw a new Limpopo river flow hydrograph taking into account the irrigation ab-
straction.
■■ Discuss the potential impacts of these flow reductions on downstream communi-
ties and downstream countries.
■■ Discuss the possible impacts on the environment, and on water quality.
■■ Propose a monitoring strategy to identify the impacts of the irrigation on the river
flow, the groundwater and the local ecosystems.
■■ Suggest methods for integrating the irrigation abstraction into the surface water
management planning.

INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA 19

EXERCICE

2
Methodology:
The solution to this problem lies in developing a simple water balance for inflows to
Integrated Water Resources and outflows from the alluvial aquifer linked to the river. For simplicity, it is convenient
Management and the
Groundwater Management to start the water balance at a time when there are no surface river flows ie. in Sep-
Framework
tember each year, but also note that we bring forward the deficit in the alluvial aquifer
for the year to date.
1. All abstractions of groundwater from the alluvial aquifer result in a decline in the
water level in the aquifer … part of the aquifer becomes “desaturated”.
2. The degree of desaturation is cumulative if the abstraction is higher than recharge,
so that the aquifer becomes progressively more empty as groundwater abstraction
for irrigation continues. The amount of groundwater in storage becomes progres-
sively less.
3. When the rainy season begins run-off / river flow is generated. When the run-off /
river flow is greater than the groundwater abstraction and there is a positive value
for the water balance*. This first goes to refilling the empty aquifer.
4. The positive balance between run-off (positive) and abstraction (negative) accu-
mulates as groundwater in storage until the aquifer becomes fully saturated again
(i.e. no deficit).
5. Once the aquifer is fully saturated, the positive balance between abstraction and
runoff becomes river flow.
6. Note that river flow is not cumulative – it is not stored anywhere; it flows down-
stream and is no longer available for recharge to the aquifer.
7. Note also that we assume that there is no delay between groundwater abstraction
and impact on the river. This may not be entirely realistic.
8. Once the rains stop, river flow declines and then ceases when run-off becomes
less than aquifer abstraction.
9. As the dry season progresses, groundwater abstraction continues and the aquifer
again becomes progressively depleted.
10. The cycle continues when the next rains begin.

*It should be noted that the river flow hydrographs from the Limpopo are al-
ready disturbed due to the fact that irrigation and groundwater abstraction are
already taking place. It will be necessary to go back in time and look at Limpopo
hydrographs from times prior to the establishment of the irrigations to be able
to assess the impact of groundwater abstractions on river flows. This can also
be achieved by comparing old pre-irrigation hydrographs with post irrigation
hydrographs. Another simple strategy is to simply calculate the volume of
abstracted groundwater in any year, and equate this to the amount of river flow
that is diverted to irrigation.

20 INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

 Month a) Rainfall mm b) River flow: no c) GW abstraction d) Monthly water e) Alluvial aquifer deficit m3/sec f) River flow with GW
GW abstraction m³/sec balance m3/sec nb: max < 0 abstraction m3/s
m³/sec e (previous) + d

Previous dry Brought Forward = -28

season

September 0 0 -6.5 -6.5 -28 - 6.5 = -34.5 0

October 17 0.2 -6.5 -6.3 -34.5 - 6.3 = -40.8 0

November 39 5.3 -6.5 -1.2 -40.8 - 1.2 = -42.0 0

December 73 27.5 -3.2 +24.3 -42 + 24.3 = -17.7 0

January 129 88.7 0 +88.7 -17.7 + 88.7 = 71.0 = 0 71.0

Table 1: LIMPOPO Water Balance:

February 108 42.1 -1.7 +40.4 0 + 40.4 = 40.4 = 0 40.4

March 19 5.4 -6.5 -1.1 -1.1 0

April 0 1.9 -6.5 -4.6 -5.7 0

May 0 1.4 -6.5 -5.1 -10.8 0

June 0 1.1 -6.5 -5.4 -16.2 0

July 0 0.7 -6.5 -5.8 -22 0

The impact of alluvial groundwater abstraction on river flow.

August 0 0.5 -6.5 -6 -28 0

Annual Totals 385 174.8 63.4 111.4 Monthly total is the deficit at that time. 111.4

Calculate the monthly water balance for each month.

Calculate the monthly water deficit in the alluvial aquifer.
Calculate the monthly river flow with groundwater abstraction.
Calculate the annual totals for all columns.

INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

NB – this is the

them to complete
participants, we will
leave last row & last
answer sheet – for the
2

three columns blank for

21
Framework
Groundwater Management
Management and the
Integrated Water Resources
EXERCICE
EXERCICE

Integrated Water Resources

Management and the
Groundwater Management
Framework

Figure 1: Beit Bridge / Musina area with alluvial irrigation development along Limpopo main-
stem river.

Figure 2: Detail showing the irrigated areas with Centre Pivots (2000 ha) and rectangular
field (4500 ha) layouts. Rectangular fields are largely Citrus, and centre pivots are for cotton.
Limpopo river runs west to east through the middle of the image.

22 INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA

 EXERCICE

Integrated Water Resources

Management and the
Groundwater Management
100
Framework

80

60

40
river flow

groundwater abstraction
20
water balance

groundwater deficit
0

-20

-40
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Figure 3: Limpopo chart showing water balance components. Vertical axis is m³/sec. River flow
line is prior to groundwater abstraction.

Zimbabwe
Flood Irrigation – 4500 ha
Mozambique

Alluvial San
ds Aquifer
Limpopo Riv
er

South Africa

Centre Pivot Irrigation

2000 ha per centre pivot

Figure 4: Schematic illustration of the Limpopo alluvial aquifer irrigation.

INTEGRATION OF GROUNDWATER MANAGEMENT INTO TRANSBOUNDARY BASIN ORGANIZATIONS IN AFRICA 23