THE WATER METABOLISM OF RESIDENTIAL BUILDINGS IN

ADAMA CITY, ETHIOPIA

Kedija Fedlu Jemal

A Thesis submitted to

The department of Architecture

School of Civil Engineering and Architecture

Presented in Partial Fulfillment of the Requirement for the Degree of

Master of Science in Environmental Architecture

Office of Graduate Studies

Adama Science and Technology University

Adama, Ethiopia
November 2020
THE WATER METABOLISM OF RESIDENTIAL BUILDINGS IN
ADAMA CITY, ETHIOPIA
Kedija Fedlu Jemal

Advisor: Tibebu Assefa (PhD)

A Thesis Submitted to

The department of Architecture

School of Civil Engineering and Architecture

Presented in Partial Fulfillment of the Requirement for the Degree of

Master of Science in Environmental Architecture

Office of postgraduate studies

Adama Science and Technology University

Adama, Ethiopia

November 2020
 APPROVAL OF BOARD OF EXAMINER

We, the undersigned, members of the Board of Examiners of the final open defense by
Kedija Fedlu Jemal has read and evaluated her thesis entitled “The water metabolism of
residential buildings in Adama city, Ethiopia.” and examined the candidate. This is,
therefore, to certify that the thesis has been accepted in partial fulfillment of the requirement
of the Degree of Master of Science in Environmental Architecture.

____________________________ _____________________ ___________________

Advisor Signature Date

____________________________ _____________________ ___________________

Chairperson Signature Date

_________________________ _____________________ ___________________

Internal Examiner Signature Date

____________________________ _____________________ ___________________

External Examiner Signature Date

________________________ _____________________ ___________________

Head of Department Signature Date

________________________ _____________________ ___________________

School dean Signature Date

________________________ _____________________ ___________________

Postgraduate dean Signature Date

 DECLARATION

I hereby declare that this MSc Thesis is my original work and has not been presented for a
degree in any other university, and all sources of material used for this thesis have been duly
acknowledged.

Name: Kedija Fedlu Jemal

Signature: ______________

This MSc Thesis has been submitted for examination with my approval as a thesis advisor.

Name: Tibebu Assefa (PhD)

Signature: _____________

Date of submission November 12, 2020

 ADVISOR’S APPROVAL SHEET

To: Architecture department

Subject: Thesis Submission

This is to certify that the thesis entitled “The water metabolism of residential buildings in
Adama city, Ethiopia” submitted in partial fulfillment of the requirements for the degree of
Master of Science in Environmental Architecture, the Graduate Program of the Department
of Architecture, and has been carried out by Kedija Fedlu ID. No PGR/18268/11, under my
supervision. Therefore, I recommend that the student has fulfilled the requirements and hence
hereby she can submit the thesis to the department.

Tibebu Assefa (PhD) ________________ _____________________

Name of major Advisor Signature Date
 ACKNOWLEDGMENT

From the beginning of the research idea, my Advisor supports me in clarifying, organizing,
and finalizing the paper. I would like to present my gratitude for Dr. Tibebu Assefa. He was
such an aspiring and supportive throughout the research. I want to thank Adama town water
supply and sewerage enterprise; specifically Ato Hassen Ture for the collaboration and
support he showed throughout this study. I have no words to thank my mother Seada for all
the sacrifices she paid for me that I could stand here today. All the credit for this work belongs
to her. At last, I couldn’t mention all of you my lecturer's, family, and friends thanks all for
your appreciation, idea, and support.
 Table of Contents

Chapter Page

LIST OF TABLES ................................................................................................................. iii

LIST OF FIGURES ............................................................................................................... iv

ACRONYM AND ABBREVIATION .................................................................................... v

ABSTRACT ........................................................................................................................... vi

CHAPTER ONE: INTRODUCTION ..................................................................................... 1

1.1 Background .............................................................................................................. 1

1.2 Statement of the problem ......................................................................................... 3

1.3 Objective of the study............................................................................................... 4

1.4 Research question ..................................................................................................... 4

1.5 Scope of the research ................................................................................................ 4

1.6 Significance of the research...................................................................................... 5

1.7 Limitation ................................................................................................................. 5

1.8 Description of the study area .................................................................................... 5

1.9 Definition of key terms ............................................................................................. 6

CHAPTER TWO: LITERATURE REVIEW ......................................................................... 7

2.1 Theoretical review .................................................................................................... 7

2.2 Contextual review................................................................................................... 15

2.3 Summary of literature review ................................................................................. 17

CHAPTER THREE: MATERIALS AND METHODS ........................................................ 18

3.1 Sampling technique ................................................................................................ 18

3.2 Data ........................................................................................................................ 21

3.3 Data collection ........................................................................................................ 21

3.4 Methods .................................................................................................................. 21

i
3.5 Data Analysis ......................................................................................................... 26

3.5.1 Residential water consumption pattern ............................................................... 26

3.5.2 Recycled water use of Adama residents ............................................................. 26

3.5.3 Rainwater harvesting capacity ............................................................................ 26

3.6 Research design ...................................................................................................... 27

CHAPTER FOUR: RESULT ................................................................................................ 28

4.1 Residential water consumption pattern .................................................................. 28

4.2 Recycled water use of Adama residents ................................................................. 36

4.3 Rainwater harvesting capacity................................................................................ 37

CHAPTER FIVE: DISCUSSION ......................................................................................... 40

5.1 Residential water consumption pattern .................................................................. 40

5.2 Recycled water use of Adama residents ................................................................. 41

5.3 Rainwater harvesting capacity................................................................................ 42

CHAPTER SIX: FINDING, CONCLUSION, AND RECOMMENDATIONS .................. 44

6.1 Finding.................................................................................................................... 44

6.2 Conclusion .............................................................................................................. 44

6.3 Recommendation .................................................................................................... 45

REFERENCE ........................................................................................................................ 46

APPENDIX-1 ........................................................................................................................ 51

ANNEX …………………………………………………………………………………….52

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 LIST OF TABLES

TABLE PAGE

Table 1: Water supply standard 2.1: water quantity, minimum basic survival water needs ... 8

Table 2: Samples per kebele ................................................................................................. 19

Table 3: WSC index goal 4 indicator 1 ................................................................................. 22

Table 4: Estimated runoff coefficient for urban surfaces...................................................... 23

Table 5: Summary of methods .............................................................................................. 25

Table 6: Volume of water used for toilet flush ..................................................................... 30

Table 7: Volume of water used for Shower .......................................................................... 31

Table 8: Volume of water used to wash cloth ....................................................................... 32

Table 9: Family size and water consumption ........................................................................ 33

Table 10: Volume of water reused by residents .................................................................... 36

Table 11: Potential support of Rainwater for potable water with family size annually ........ 39

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 LIST OF FIGURES

Figure 1: The study area .......................................................................................................... 6

Figure 2: Digitized Samples (Google Earth lastly updated 09.09.2019) .............................. 20

Figure 3: Thiessen polygon ................................................................................................... 24

Figure 4: Research design ..................................................................................................... 27

Figure 5: Tap water availability ............................................................................................ 28

Figure 6: Average indoor water use in percentage................................................................ 29

Figure 7: Overhead shower water use by duration (min) and frequency per week .............. 30

Figure 8: Relationship between the volume of water consumed and family size ................. 32

Figure 9: Monthly average water consumption by family size ............................................. 35

Figure 10: Linear water flow per person per day .................................................................. 36

Figure 11: Monthly potential volume of rainwater ............................................................... 37

Figure 12: Monthly percentage contribution of rainwater harvesting potential ................... 38

Figure 13: Potential estimated harvested rainwater volume ................................................. 38

iv
 ACRONYM AND ABBREVIATION

AWSSE Adama Water Supply and Sewerage Service Enterprise

GIS Geographic Information System

GTP II Growth and transformation plan II

L Liter

LCA Life cycle analysis

L/C/D Liters per capita per day

m.a.s.l Mean above sea level

RWH Rainwater harvesting

UN United Nation

WHO World Health Organization

WSC Water sensitive city

v
 ABSTRACT

Water is the basic metabolic requirements of a city. The fastest population growth and raise
per capita income put pressure on the water resource. Within the scarce supply, consumption
intensifies the scarcity. The research aims to identify water consumption pattern, recycled
water use, and rainwater harvesting potential of residences in the Oromia region Adama city
using 203 samples selected by combined stratified and simple random sampling. Resident’s
consumption data using interview and meter reading from Adama water supply, sanitation,
and sewerage enterprise were used. MS Excel was used to analyze data and plot graphs. The
result of the analysis had shown inconsistent supply in which 84% was consumed for hygiene
purposes including 33.7% for cloth washing and 24.7% for toilet flushing. Indoor utilities,
frequency, and duration of indoor activities, and family size affect consumption volume
directly. The consumption trend is linear where the input water expelled without further uses.
From 20,199.4m2 sampled residents roof area with 804mm mean annual rainfall potentially
15,428 m3 of rainwater can be harvested that could support the supply. It is concluded that
the water management of Adana residents is poor with low environmental consciousness. The
largest percentage of potable water is used for non-potable purposes which can be easily
compensated by rainwater harvesting and greywater reusing. It is finally recommended to
offset the non-potable use of water by harvesting rainwater and aware consumers the
importance of roof water harvesting system to be sustainable enough. Tariff adjustment can
also be done for those who used rainwater and offset most of their potable water demand
from the municipality.

Keywords: consumption, demand management, potable water, rainwater, water supply

vi
 CHAPTER ONE

INTRODUCTION

Water is the blood of life. Human life and the ecosystem depend on the availability of
efficient water for existence. Adama city is located in the major transportation corridor and
is one of the fastest-growing intermediary cities of Ethiopia with a high rate of migration
which Intensifies water stress. Due to this fact, the motive for this research is the desire to
contribute a sustainable solution that is environmentally and financially acceptable both by
the residents and stakeholders for the critical survival question of water scarcity in Adama
city.

This chapter describes the background information around the topic area that has been done
before, states; the problem, objective, research question, scope, and significance of the study.

1.1 Background

The water treatment expert Wolman introduces the concept of urban metabolism in 1965.
Inhabitants of a city require resources for their livelihood. Metabolic flow refers to the flow
of material and resources in cities. Urban metabolism is broadly subdivided into two
processes as anabolic which refers to resource consumption to produce products and
catabolic refers to decomposition and recycling of wastes (Zhang et al., 2015). Water is the
most essential resource required for life. Life exists with water and perishes without it.
Human activities in the environment are water-centered and also Two-thirds of the human
body is composed of water and requires water to live (Chaplin, 2001).

Cities are the center of human activities which represent an important point of contact
between natural and socio-economic systems. The expansion of cities and unsustainable
urban development challenges the water supply which becomes the basic metabolic problem
of cities globally (Zhang et al., 2015). The history of urban hydro-social transition shows
from human and nature interdependence to a biocentric approach. In hydro-precarity which
is the first era, water management objective was based on expanding the service later on at
the era of hydro-modernism changed to industrializing and after 1992 hydro-security focuses
on multi-functioning and sustainable approaches like rainwater harvesting. Each country
experiences its geo-historical sequence of water service development but in developing

1
countries, there are still billions of peoples without adequate access to basic water service
(Meissner et al., 2017).

This century marks the proportion of the urban population surpassed living in a rural
environment which makes sustainable practice hard (Brown et al., 2009). The urban
population is expected to increase from 3.6 billion to 6.3 billion by 2050 also by the same
year it’s expected that the global population to increase from its current level of 7 billion to
9.2 billion (UN, 2012). This along with unprecedented economic development leads to
unparalleled stress in the water system.

Increasing city density due to urbanization was one of the factors for the expansion of urban
water service but in developing nations the water service system is still poor due to a lack of
clear governmental policy and economic weakness in addition to urbanization, population
growth, demand-driven supply which didn’t follow sustainable approaches, and Peri-urban
areas that combine urban and rural characteristics (Meissner et al., 2017). This implies most
of the developing countries are in the era of hydro-precarity where water is not secure and
institutions work mainly on expanding the service.

Globally, the water supply is in critical stress due to demand leading cities to a challenge of
effective water resource management. Supplies that support large populations are becoming
compromised like the world’s largest rivers such as the Colorado River, Rio Grande, Indus
River, and the Yellow River is running dry long before they reach their river mouths. Also,
land-use dynamics affect indoor demand-supply it creates a storm at the level of cluster and
sub-catchment (Willuweit & O’Sullivan, 2013).

A resource is a key to the sustenance of a city and water as a crucial resource is depleting
globally which should be managed efficiently. All over the world cities are facing a range of
regional pressure especially the developing nations. The problem is not only the supply but
disposal, environmental impacts, and overutilization so to develop solution studies should
be done on a global and regional scale. After all the studies should be used for the
management of urban water as a design parameter and monitoring consumption
(Vairavamoorthy, 2007)

How water is managed affects the health of ecosystems. While climate change will create
important pressures on water, it is not currently the most important driver of these pressures

2
outside the water sector. The most important drivers, forces, and processes generated by
human activities are demographics and the increasing consumption that comes with rising
per capita incomes. Growing pressure on water resources affects ecosystems and threatens
the ecosystem goods and services on which life and livelihoods depend (United, n.d.).

Water demand management should be based on forecasted water demand, stormwater, and
the whole life cycle cost therefore it important to quantify water resources by expressing
input-output in the form of a chart to determine the daily metabolic requirement of a city
(Willuweit & O’Sullivan, 2013; Zhang et al., 2015).

1.2 Statement of the problem

Access to water is recognized as a human right by the United Nations. Although residence
covers the largest percent coverage in land use, the primary goal of water service should be
consumers or residents because development comes after survival. The fastest urbanization
and increasing consumption that comes with rising per capita incomes put pressure on water
resources. By nature, the human interest is unlimited while the resource is limited and within
this situation, resource consumption should be wise for the sustainability of the ecosystem
but the less concern and awareness of this critical condition create a gap in the use of
resources in developing countries. This time the human race is facing threatening challenges
due to resource depletion. The increase in per capita income of developing countries led to
an increase in demand for comfort and luxury which lead to extravagance and waste.
Misunderstanding of Globalization trends in the developing countries is creating vast
consumption problems that could lead to crisis. Evaluating product from inputs to outputs
and potential environmental impacts throughout its life cycle is necessary. Water as a vital
survival component of the environment should be evaluated regarding human consumption.

The study undertaken by Fekrudin & Ababa, (2019) in eight kebeles of the three Adama sub-
cities (Boku, Dabe, and Lugo) showed that Adama water supply doesn’t satisfy the
increasing population and the demand. According to the GTP II standard, it was planned to
address 80 l/c/d but 48.6 l/c/d is supplied for residents of Adama. Population growth,
urbanization, migration, and an increase in per capita income intensified water scarcity in
Adama. The scarce and intermittent supply of water exposes Adama residents to water
scarcity. Knowing this fact and understanding that even if atmospheric water is one of the
resources that one can get easily with no cost the collection and use of rainwater seem not

3
that much practical by the residents of Adama. Another is reusing used water which is coined
in the literature of Architectural sustainability. This is also not practiced as it is found in a
short mockup observation of the use of water in residents of the city.

The water supply performance of Adam city was examined by Fekrudin & Ababa, 2019 only
in three sub cites of Adama. The study didn’t assess the end-use of water which intensifies
scarcity so this study intended to fill the gap in the water supply system which is driven by
the demand by understanding and quantifying the domestic water metabolism of Adama city
in the eighteen kebeles to make the residents sustainable.

1.3 Objective of the study

General objective:

To understand the domestic water metabolism of Adama city.

Specific objectives:

1. To assess residential water consumption patterns.

2. To estimate the recycled water use.
3. To compute rainwater harvesting capacity from the resident roof.

1.4 Research question

1. What type of water use pattern is practiced by Adama residents?

2. How much water is recycled?
3. How much water can be harvested from the resident's roof and to what extent it augments
the water needs?
1.5 Scope of the research

The study focuses only on Adama city's residential water consumption after the water has
been delivered to the resident's house by a pipe. Residential water is highly essential since it
is needed for survival. It has been confined within the 18 Kebeles of Adama city and spans
for seven months from March to August 2020 at which rainwater, is both scarce and
abundant.

4
1.6 Significance of the research

Water is vital for the livelihood of residents in any city. Supplying potable water for residents
to the level of their satisfaction is critical. The domestic water metabolism shows the
residents' habit of their water consumption from cradle to grave. By this, residents will
understand their extravagant usage of the scarce water resources supplied from the municipal
main spending huge resource to water each resident. They could also learn to utilize
untapped rainwater at their compound to offset their municipal water demand thereby spares
their finance for any other crucial benefits (i.e. save money). The sole supplier of water for
the city, the municipality of Adama, would also benefit to reroute its supply to other uses
such as industrial and urban agriculture activities. It also relieves the administration from
public annoyance which can be escalated to political unrest as water is critical for survival.
The study is also beneficial for researchers to do similar types of research for other cities of
Ethiopia so as to contribute their part for sustainable water use.

1.7 Limitation

It has been tried to address the objective of this research as much as possible however, the
sudden outbreak of the COVID-19 pandemic has affected the face-to-face data collection
and forced to use of secondary data gained from Adama water supply, sanitation, and
sewerage enterprise. Besides, as the residents do not measure each of their water use for
different activities, standards from different pieces of literature, have been used to estimate
the quantity of water. Except for all these, the research has been done diligently.

1.8 Description of the study area

Adama is one of the cities found in Oromia National regional state of Ethiopia. The city is
located about 100 km southeast of the national capital Addis Ababa along the main highway
leading to Djibouti. It is situated between 8.250-8.370 N longitude and 39.120-39.220 E
latitude at an altitude that ranges from 1444 to 1974 m.a.s.l covering 134.1 km2. It has a
tropical wet-dry climate according to Köppen climate classification. Its average annual
temperature and precipitation are 20.5 °C and 804 mm, respectively (fig.1).

5
 Figure 1: The study area

1.9 Definition of key terms

Metabolism: Quantitative assessment of resource flow to evaluate city sustainability.

Anabolic processes: Resource consumption to produce products.

Catabolic processes: Decomposition and recycling of wastes.

Urban water metabolism: Framework used to study water flowing through and being
transformed and consumed.

Linear water metabolism: Removal of water after a single-use.

Circular water metabolism: Recycling and reusing of water.

Water consumption pattern: The end use of water for indoor and outdoor activities.

Rooftop rainwater harvesting: The easiest and most common method of capturing
rainwater for utilization.

6
 CHAPTER TWO

LITERATURE REVIEW

2.1 Theoretical review

2.1.1 Water basics

Water is the largest percentage composition of the environment and an essential element for
life. “We all live on this beautiful water planet which we have mistakenly chosen to call
earth” Anonyms. Even though water covers the largest percentage of the earth only 3% of it
is fresh the rest is saline and ocean-based. Even from 3% of the freshwater, only 1% of it is
easily accessed with much of it taped in snowfields. The Hydrological cycle is responsible
for rain; which is the primary source of water in the form of precipitation after surface
evaporation and precipitation (McMullan, 2018). Water is a source of life. Early human lived
near water source by which survival and emigration pattern was affected. Reliable water
supply was the base for settlement (C.J. Kroehler, 2014). Because of its clear importance,
water is that the most studied material on Earth. Even though it is crucial for survival and
well-studied, it is poorly understood not only by human beings but also by scientists working
with it every day (Chaplin, 2001). Nowadays ground and surface water are becoming the
two main sources of the modern water supply system. Groundwater is found under the earth's
surface in rock fractures and soil pores space. It is an important resource for a nation. It
requires skill and finance to access. It is not directly connected to the hydrology cycle and
due to urbanization, the hydrological cycles have got into profound impact. Urbanization
transforms the natural surface into an impermeable surface by construction and pavement
which reduces the infiltration of water to recharge groundwater and increases runoff
(Lawrence et al., 1998). Even if surface water is directly connected to the hydrological cycle,
overutilization is affecting it (Arpke & Hutzler, 2006). The ecosystem balance is getting an
endangered and critical challenge due to unparalleled human activity.

2.1.2 Basic water requirements for domestic consumption

Domestic water is all the water used for activities taking place in the resident's house. The
activities subdivided broadly as consumption, hygiene, and amenity. In some cases, water is
used for additional productive purposes such as small scale gardening and livestock to
support the economy and livelihood consumption of residents. The volume of water being

7
consumed depends on accessibility or service level, reliability, and the cost of water (Howard
& Bartram, 2003). Furthermore, an individual's life standard or economic status, climatic
condition, and culture have an impact on consumption volume. The above variables and
human unpredictable behavior make it difficult to generalize the standard water demand
pattern Agudelo-vera et al., (2013) but some norms have been proposed for the quantity of
water to be supplied and used (Table 1). According to the WHO report and sphere, a
minimum of 7.5l/c/d meets most people's needs under most conditions. Humanitarian
Charter and Minimum Standards in Humanitarian Response states 50 liters per person per
day as the minimum acceptable amount of water in an urban middle-income context (Sphere
Association, 2018). Drinking water volume varies regarding the human-environmental
interaction and personal experiences based on this WHO standard is 1-2.4L for normal
condition, 2.8-3.4L for average high temperature, and above 3.7 for moderate activity (Guy
Howard, 2003).

Table 1: Water supply standard 2.1: water quantity, minimum basic survival water needs

Needs Quantity Adapt to context based on

(liter/person/day)

Survival: water intake (drink 2.5-3 Climate and individual physiology

and food)

Hygiene practice 2-6 The social and cultural norm

Basic cooking 3-6 Food type, Social, and cultural

norm

Total basic water 7.5-15

(Source: The Sphere Handbook: *Humanitarian Charter and Minimum Standards in Humanitarian Response)

2.1.3 Water supply Challenges

Water supply is the provision of water by public utilities, commercial and community
organizations, or private endeavors using pumps and pipes. Water supply is a crucial element
of human survival. Cities around the world are facing challenges in the management of ever
scarce water resources due to depletion and overutilization (Vairavamoorthy, 2007).

8
Population growth is the main global phenomenon creating pressure on resources. As the
population grows peoples migrate from an agricultural-based rural area to industrial-based
urban areas for a better life standard which put a critical impact on water supply (C.A. Grady
et al., 2014). In developing countries, unstructured settlements in urban areas along with
high demand create a concern of supply and shortage whereas still, large sections of the
community are living without a safe water supply (Serrao-Neumann et al., 2017). Hydrology
is an interrelated section of the environment with land use planning. Historically land fabric
affects hydrology and now the world is facing water management issues due to the above
urban settlement and expansion issues (Serrao-Neumann et al., 2017).

The new era of economic development and modernization had created an impact on the
natural environment and resources. A variety of environmental movements has been
exploded globally because of industrialization and economic development consequences in
consumption and removal of resources. Such movements aim at creating Environmental
consciousness in the use and management of resources. According to the study by Arpke &
Hutzler (2006), indoor water uses have a large impact on the water supply.

From the institutional level up to the individual units, neglected water management strategies
are the other challenges for the water supply. habitual consumption trends in society are the
main indicators of poor water management (Bauer et al., 2010; McMullan, 2018). The future
is in the question of a clean source of drinking water. Individuals strive for increased comfort,
therefore, the emphasis will thus be got to place on reducing energy and water requirement
without decreasing either comfort level or living standard (Bauer et al., 2010).

The water supply system is based on the rate of production and consumption. This supply
requires extraction, purification, and delivery cost. Although in the developing nations the
supply rate is very low related to the industrial world the socio-economic and political
situations play its role in the scarcity(Vairavamoorthy, 2007). To meet this challenge there
should be a paradigm shift in the way water being used and removed (Vairavamoorthy,
2007).

2.1.4 Origin of urban metabolism for planning water sensitive cities

The metabolism concept originates from the contradiction between economic development
and the ecological environment due to the industrial revolution and urbanization. It was first
used by Wolman in 1965 to evaluate environmental resources and consumption (Zhang,

9
2013). Metabolism is a quantitative assessment of resource flow used to evaluate the
sustainability of a city. Sustainability is maintaining the natural system. The planet carrying
capacity depends on natural limitations (Mostafavi et al., 2014). From the ranges of urban
resource sustainability evaluating approaches, metabolism is preferred the most (Zhang,
2013).

A water metabolism study is crucial for the future city's sustainability and high relevance to
the water industry. Urban sustainability comes from each unit. Water is the most critical
element in urban flow. Water sensitive urban design focuses on water management, runoff
use, reuse, and water-saving measures (Paolini & Cecere, 2015).

Cities around the globe struggle to become water-sensitive and enhance livability (Rogers et
al., 2020). Water service plays an important role in cities' livability, sustainability, and
productivity (Chesterfield et al., 2016). Water-sensitive city concept emerging coiled to the
Australian academic sector due to the millennium water drought which becomes top of
political and community concern of the country. The target of the concept was the delivery
of safe water service to all sustainably based on three pillars; water supply catchment:
diversify source also reduces the sole dependence on large capital-intensive infrastructure
network, providing ecosystem service: featuring green spaces, and comprise water sensitive
community. Academically it is considered the final stage in the evolution of urban water
management. The shift in urban water management promotes reliable water supply, quality
of water at the point of use, and increase technical, economical, and environmental resilience
performance (Bichai & Cabrera Flamini, 2018).

WSC index is a tool used to benchmark a city's current performance based on the seven goals
of water sensitive city (indicators ensure good water-sensitive governance, increase
community capital, achieve equity of essential services, improve productivity and resource
efficiency, improve ecological health, ensure quality urban spaces, and promote adaptive
infrastructure) in three dimensions; societal, biophysical, and ecological. The goals were
further organized into 34 corresponding indicators (Chesterfield et al., 2016; Rogers et al.,
2020). WSC index is a quantitative framework based on a qualitative rating description used
as a diagnostic tool to set targets and track progress, inform management response to improve
water-sensitive to enable the transition to a Water Sensitive City; and Foster industry
collaboration (Rogers et al., 2020).

10
Higher integration between water and land-use coming up is important for each urban system
departments to still exist whereas reducing their impact on water resources at the city-region
scale (Paolini & Cecere, 2015; Serrao-Neumann et al., 2017). Urban design and planning
for a sustainable city should integrate ecosystem service which is necessary for all other
ecosystems like water cycling into the urban environment, focuses on building Water
Sensitive Communities and Institutions, and create water Supply Catchments Cities
(Mostafavi et al., 2014).

The urban water performance evaluation of the three Australia city regions by water
metabolism framework helps to better understand the impact of water sensitive intervention
and inform water management by comparing the current water use and after the
implementation of water sensitive interventions which helps by improving water efficiency
and diversifying supply by the use of rainwater and recycling (Renouf et al., 2018).

To solve current urban water issues, it's necessary to investigate and solve the metabolic
processes by reducing metabolism and reusing water in consideration with the standard of
the demand. In a circular model, the input water is reused many times that minimize wastage.
Reducing material flows in the city with increasing human livability and overall well-being
represents each a transparent property pathway and also a challenge (Paolini & Cecere, 2015;
Serrao-Neumann et al., 2017).

2.1.5 Domestic water use study using LCA

LCA is a cradle to grave analysis or comparative tool used for evaluating the production,
consumption, and environmental burdens of a product. It is a process-based framework used
to evaluate the metabolic flow of resources within a city. LCA is an accepted comprehensive
method by the environmental research community. The domestic water cycle has four
phases’; natural existence as a source, treatment, consumption, and removal with the use of
energy in the transition of each phase (Arpke & Hutzler, 2006).

It took energy and finance to treat and deliver water to users (S. Lawson et al., 2014;
McMullan, 2018). cleaning water through settling, filtering, and disinfecting took place
before millennia (C.J. Kroehler, 2014). Water-energy nexus is the energy that took to collect,
clean, store, distribute, and dispose of water. It depends on the source of water. Drinking
water in the USA requires 0.51 KW/m3 energy and 0.39 KW/m3 in Australia. It's been
increasing throughout the years due to demand and energy intensive-sources. Groundwater

11
extraction takes 30% more energy than surface water whereas it took 4.3KW/m3 for
desalination and 1.7KW/m3 for recycling (S. Lawson et al., 2014;).

2.1.6 Water conservation and tools for conservation

Conservation means generally the wise use of resources. Water conservation is managing
the entire water cycle, starting from door-step resources like rainwater and try to get as many
uses out of that water as possible (Yudelson, 2007). The efficient use of water resources is
one of the criteria for a green building. Households are the main consumers of water
resources as a result efficient utilization minimizes water footprint and promotes ecosystem
sustainability (Bauer et al., 2010). There are a lot of factors that affect water consumption
volume in residents. According to the national institute of building science, from the main
factors which put pressure on the water resource one of them is inefficient home appliances
water consumption which includes toilets and urinals flush, showerheads, dishwashers, and
washing machines (Inman & Jeffrey, 2006). For instance, the Standard washing machine
consumes 114-189 liters of water per wash but a new energy star certified washer takes 38
liters per wash which minimizes water consumption 30-60%. Low flush toilets that use 3.8-
6 liters save 15-25% of water (Lancaster, 2014). Water conservation technologies and
strategies are often the most overlooked aspects of whole building design strategies but it is
crucial to consider such aspects for the efficient utilization of water resources. (Water
Conservation | WBDG - Whole Building Design Guide, n.d.).

The tools for residential water conservation review by Inman & Jeffrey (2006) implies a
work that should have to be done on the demand-side management for the water scarcity
around the globe than exploiting new resource as a solution. A small amount of water is
required for drinking but much for washing and cleaning (McMullan, 2018). On average
68% of drinking water is used for toilet and washing, 19% for laundry and dishwashing, the
remaining for cooking, drinking, and gardening (Bauer et al., 2010). Low level of
Environmental consciousness, need for comfort and luxury, and consumption habits are
other factors that affect consumption volume. Some habits like leaving the tap running at the
time of shaving, face washing or teeth cleaning, utensils and vegetable washing, and taking
shower for a long time wastes water. As statistics show shower decrease 35% of water
instead of a bath, and 75% of tooth-cleaning water decrease if the pipe opens when needed
(Bauer et al., 2010).

12
Implementing water conservation tools needs commitment from both sides; institutions and
consumers. Awareness creation, maintenance, regulations, water pricing with the
consideration of low-income customers, and outdoor consumption restriction are some of
the measures that could be adopted to manage demand and promote conservation for
managing the scarce demand. (Inman & Jeffrey, 2006).

Due to the fact that the rate of the hydrology cycle doesn’t meet demand nowadays, the
traditional approaches like rainwater harvesting and conservation are coming back as a trend
for sustainable approaches (Lancaster, 2014). Innovative management and water sensitive
interventions like supply diversification and efficient use are required to withstand the water
demand stress (Renouf et al., 2018).

2.1.7 Empirical experience of water consumption globally

European Mediterranean coasts (France, Italy, and Spain) volume of water consumption
increase in the 1960s and 1970s, reaching its highest peaks in the late 1990s and early 2000s
due to city expansion and population also the interest of green areas incorporation by the
scientific community in the urban areas. In the metropolitan area of Barcelona (Spain)
percentage of indoor water consumption for toilets and taps is high (29-34%) followed or
sometimes precede by hygiene (bath and shower) (22-34%). Other uses consist such as;
Laundry (14-17%), dishwashing (16-12%), food and drinking (5-10%), and other uses (3-
5%) (Morote et al., 2016).

Water usage drops in the mid and later 1990s on European Mediterranean coasts. For
instance in Germany between 1994 and 2004 water consumption drop by 13%. The average
personal consumption of water per day reaches 126L. In Spain, in 2005 the personal
consumption of water per day was 225L which drops by 23% in 2012 to 198 l/c/d, and in
Denmark 1989-2008 consumption drop by 22%. Comparatively from the European
Mediterranean coast countries Jerusalem (650 l/c/d), Sydney (206 l/c/d), London (154 l/c/d),
and the USA (409 l/c/d) consume a large volume of water (Inman & Jeffrey, 2006; Morote
et al., 2016).

Factors for the drop in the consumption trend include; progression of personal habits
(citizens awareness with water-saving ), social and demographic changes, higher water
price, technological advancements (efficient technologies for home appliances), and drought
which translate water use (the use of greywater and rainwater) (Morote et al., 2016). The

13
study by Thompson et al., (2000) in selected East Africa countries urban areas implies the
factor of available water in the consumption volume. The mean per capita daily water use of
households with a pipe is 64.2 litters but unpiped households consume only 24.3 L per day.
Kenya, Tanzania, and Uganda consume at average daily 45.2, 70.5, and 47 liters of water
per person, respectively.

Developed nations are now working on minimizing consumption and promoting

conservation and sustainable approaches due to the environmental impacts and supply
challenges whereas developing nations are struggling with addressing efficient water supply
that neglects the incorporation of sustainable approaches (Morote et al., 2016; Thompson et
al., 2000).

2.1.8 Rainwater harvesting

Rainwater harvesting is the capturing, storage, and use of rainwater close to where it falls.
Rain is the first form of water in the hydrologic cycle in the continuous circulation of water
in the earth-atmosphere system. It is a freely available resource and naturally distilled
through evaporation (Lancaster, 2014). Historically it has been recorded that many cultures
throughout the world used captured rainwater (Kinkade-Levario, 2007). Roof runoff was the
main source of Water in the 6thcentury B.C. for the Phoenician and Carthaginians
settlements. It's been practiced in Italy and Rome from 300-600 A.D and 4,000 years old
tradition in the Indian subcontinent. It also practiced in China 6,000 years before and 2,000
years back in North Africa, the Mediterranean, the middle east, and Thailand (Lancaster,
2014).

Rainwater captured from roof catchments is the easiest and most common method used to
harvest rainwater which can be used for residential potable water. The amount of water
collected depends on catchment size, surface texture, surface porosity, and slope conditions.
It provides easily and economically in a cheap way a self-sufficient water supply located
close to the user which reduces the use and dependency on municipal water, mitigates urban
flooding, and as a result, reduces soil erosion in urban areas Kinkade-Levario (2007) but
gradually this tradition moved to ground and surface water pumping and utilization as a
source of water in the modern water management system over the past 150 years. This
system highlight rainwater as a source of a flood that should be drained (Lancaster, 2014).
The impact on the ecosystem and resource is now implying the measures that should have

14
to be done on the utilization of the neglected resource. Rainwater use was limited in the areas
where water access was limited but worldwide this century brought water supply challenge,
accordingly rainwater harvesting system become an alternative water supply system.
Systematic rainwater utilization reduces drinking water consumption by half. 68% of the
drinking water is used for toilet and washing so rainwater which is soft doesn’t have calcium
carbonate or magnesium needs less powder could help the demand for hygiene and amenity.
On the other hand, rainwater is a natural fertilizer having sulfur and other minerals from the
atmospheric dust for plants nourishment and growth which makes it suitable for gardening
purposes (Bauer et al., 2010; Lancaster, 2014).

2.2 Contextual review

2.2.1 Ethiopian Water Resource Management

By Article 55 (1) of the Constitution of the Federal Democratic Republic of Ethiopia (FDRE,
1995), Proclamation No. 1997/2000, Ethiopian Water Resource Management was
proclaimed on the 9th of March 2000. The purpose includes ensuring that the water resources
of the country are protected and utilized for the highest social and economic benefits of the
people of Ethiopia (Proclamation No, 197/2000). Under this proclamation, water resource is
defined as surface or groundwater which doesn’t include rain or stormwater as a resource to
be utilized. Also states water resource management as; utilization, conservation, protection,
and control of the existing water resource. Ethiopia water authority is the responsible
institute for the execution.

2.2.2 Adama Town Water Supply system

Adama is a rapidly growing economic center and transportation hub of Ethiopia situated in
Rift valley within the Awash River watershed. It was established in 1916 on flat terrain
characteristics and surrounded by plateaus, mountainous, and ridged topography. The first
water supply system was constructed by the former Ethiopian Electric Light and Power
Authority (EELPA) in 1948 using Ten Boreholes at the place Melka Hidda along Wonji
Road. The water was characterized by high Fluoride concentration. It serves till 1979 and
transferred to Water Supply and Sewerage Authority. In November 2002 again restructured
to Adama Water Supply and Sewerage Service Enterprise which is a municipality-owned
company responsible for water and sewerage service in Adama (Enterprise, 2012). In
Ethiopia, the cities of Addis Ababa, Adama, and Hawassa are facing the issues of urban

15
dynamics due to their uncontrolled fast-growing nature Terfa et al., (2019)Which puts
pressure on the water supply system.

Even though Ethiopia is the source of many major rivers including the Nile which constitute
more than 85 %, groundwater is being used for drinking as the main source. The country
access only 3% of the water resource (Keredin Temam Siraj, 2016). In the case of Adama,
the groundwater contains fluoride in high content. There are more than 20 boreholes, from
which only 3 of them are operational for the case of emergency and as an alternative source.
Also, there are private boreholes with permission. The main source of fresh drinking water
for the city is the upper catchment of the Awash River.

The Awash River stretches 1,200 km; located 15 km from the center of Adama and 3 km
downstream of the Koka dam. The quantity of raw water being used from the Awash River
sources was around 285 l/s (24,624 m3/d) before the upgrade system. The newly upgraded
system provides 411 l/s which cover only 78% of the demand. From the total demand,
residence covers 63%. It is estimated that domestic water Demand will increase by a double
rate in 2025 (Enterprise, 2012).

The strategic direction of the second growth and transformation plan of Ethiopia in the
potable water sector is the efficient utilization and development of potential water resources
with increasing total coverage. The planned period for the achievement of the goal is about
to come to an end but the goals are not achieved fully. According to GTP II standard, it was
planned to satisfy the water demand by the provision of, (rural; 25 l/c/d within 1km radius,
Urban: based on-demand categories of 100, 80, 60, 50 and 40 l/c/d from first to fifth level
towns, respectively). The cities ranked based on the population size (National Planning
Commission, 2016). Adama is categorized under Level-II city with a population of 220,212
(CSA, 2007) and the current population based on a CSA official population projection is
410,738 but the average per capita consumption of Adama city doesn’t fulfill the standard,
and still, there is demand and supply gap with 34.67% water loss from system input volume
(Fekrudin & Ababa, 2019). The rural, urban, and national level water supply coverage was
estimated as 59%, 51%, and 58% respectively (National Planning Commission, 2016).

16
2.3 Summary of literature review

Water is the basic requirement for life and a well-studied but still misunderstood resource.
Globally the increase in water demand creates supply challenges so frameworks developed
for quantitative assessment of resource flow for sustainability such as urban metabolism and
LCA. Also, water sensitive city concept developed by the pillars of minimizing water usage
and diversifying water supply using; recycled greywater, and harvested rainwater and
stormwater to minimize the demand-supply gap.
Under the proclamation of Ethiopia Water Resource Management greywater, rainwater, and
stormwater are not proclaimed as water resources. Currently, Adama city is struggling with
the water supply challenges of the unsatisfied and ever-increasing demand by a centralized
water supply system that neglects sustainable approaches that are financially and
economically reliable.

17
 CHAPTER THREE

MATERIALS AND METHODS

3.1 Sampling technique

Adama city is divided into six sub-city administrations, which are in turn divided into 18
kebeles. The sampling unit is households with individual connections located in the 18
kebeles. A combination of simple random and stratified sampling technique was used since
it gives the proportional probability for all the sampled populations.

The National Census report shows 59,431 housing units (CSA, 2007) found in Adama city.
It is estimated that the current number of housing units could be 64,701 from those housing
units 30,416 connected to the municipal water line based on the AWSSE report so taking
this number as a population the sample was extracted by using the Taro Yamane (1967:886)
sampling formula. The samples were selected randomly to represent the large population
without bias. Similar hydrology studies like (Asgedom, 2014; Umegbolu, 2017) use the
formula for determining sample size.

Formula 1: n = N / (1 + Ne2)

Where; n= sample size, N = population size (30,416), and e = Margin of error (MoE) which
is 0.07 for 93% confident level. The total sample is 203. Graphically the digitized Samples
are illustrated under Fig. 2.

Tables 2 present the samples per each Kebele using the method of proportional allocation
defined by the formula:

Formula 2: 𝑛𝑝𝑒𝑟 𝐾𝑒𝑏𝑒𝑙𝑒 = 𝑛𝑡𝑜𝑡𝑎𝑙 × 𝑝𝑝𝑒𝑟 𝑘𝑒𝑏𝑒𝑙𝑒

𝑁𝑃𝑒𝑟 𝐾𝑒𝑏𝑒𝑙𝑒
Formula 3: 𝑝𝑝𝑒𝑟 𝐾𝑒𝑏𝑒𝑙𝑒 =
𝑁𝑡

18
 Table 2: Samples per kebele

Kebele Total number of residences with a private connection Sample size

(population)

01 4,948 33

02 2,624 18

03 1,244 8

04 3,415 23

05 711 5

06 507 3

07 685 5

08 526 4

09 2,034 13

10 438 3

11 3,082 21

12 681 4

13 3,441 22

14 3,414 23

Boku shana 597 4

Dhaka Adi 1,153 8

Dabe Sollogee 460 3

Melkaa Adaamaa 456 3

19
The randomly selected customer’s water meter GPS data collected all together in an excel
sheet and added to ArcGIS software as a table data to allocate it exactly in the Adama kebele
shapefile, then this data converted into KMZ file format to be interpreted in Google Earth.
After conversion, the data loaded to Google Earth, and the related house roofs were digitized
from it. The Google Earth digitized image is saved back as a KMZ file format. Again using
the conversion tool in Arc GIS the KMZ file converted to the Arc GIS layer (Fig. 2).

Figure 2: Digitized Samples (Google Earth lastly updated 09.09.2019)

20
3.2 Data

The monthly billed water consumption in meter cube, the roof area of the residential houses
in meter square, and rainfall data in mm were collected. Data sets were collected from
residents, Adama town water supply and sewerage enterprise reports, unpublished
documents, journals, water consumption standard documents, aerial photos, meteorological
data, and books.

3.3 Data collection

Before the pandemic, it was planned to collect the data using a questionnaire by conducting
house to house survey. Before this, to be sure a pilot study has been done using this
questionnaire (appendix-1) from March 1-7, 2020. As it is explained in (Project, 2018) the
best way to collect water consumption data is by using observation and questionnaires or
group discussion. But due to the pandemic, the resident's water consumption volume for
different activities was collected by using a phone interview. The data collection method for
each objective and methodology is generalized in Table 5 below.

3.4 Methods

3.4.1 Residential water consumption pattern

To get a wider view of consumption; sampled residents volume of consumption collected

from the households head by interview using their contact number registered on the AWSSE
customer report by raising the questions organized under Appendix-1 and meter reading data
was taken from AWSSE customers report. The mean value of annual consumption data
divided by the number of days (30) and organized by family size to determine the correlation
between consumption and family size using regression. Under each category, the maximum
and minimum range identified and mean and standard deviation calculated using the
formulas;

Formula 4: Mean: x̅ = ∑ 𝑥 /𝑁

Where; x = sum of all data points, N = number of data points/population

2
Formula 5: Standard deviation 𝜎 = √∑ (𝑥𝑖 − x̅ ) /𝑁

21
Where; xi = each value from the population, x̅ = the population mean, N = size of the
population *

3.4.2 Recycled water use of Adama residents

The mean volume of water used by residents diagrammatically presented using the Sankey
diagram. Each square represents 10L of water and the arrow width represents the volume of
water used for specific indoor/outdoor activity. The performance level rated by the
ecological dimension of the WSC index goal “Improve productivity & resource efficiency”
using the maximized resource recovery indicator (Table. 3). Scoring was based on a rating
from 1 to 5, assigned according to the description that Adama city best fits its current
situation.

Table 3: WSC index goal 4 indicator 1

Indicator Rating Scale

Optimized resource recovery: Optimize the 1. No resource recovery occurs. All

recovery of water, energy, heat, and recoverable resources are wasted
nutrients through the circular design of
2. Low level of recovery. Resource
water systems.
recovery is considered but remains
incidental and limited to specific
recoverable resources such as recycled
water.

3. Fair level of recovery of one or two

recoverable resources usually wastewater
recycling or biogas, occurs.

4. Fairly high levels of resource recovery of

a number of recoverable resources occur.
New infrastructure and demonstration
projects used to provide proof-of-concept
for novel ideas and innovation in
technology.

22
 5. High levels of resource recovery across
most recoverable resources. Practices are
common across all new infrastructure, and
progressive upgrade of existing
infrastructure occurs.

(Source: Water Sensitive Cities Index: A diagnostic tool to assess water sensitivity and guide management actions.)

3.4.3 Rainwater harvesting

By calculating the annual rainfall from station five (fig. 3) and digitize the roof area from
Google Earth (fig. 2) the total volume of water that can be harvested from the residence's
roof calculated by;

Formula 6:

net runoff (𝑚3 ) = catchment area(m2 ) × runoff coffiecent × rain fall (mm) × (0.001)

Table 4: Estimated runoff coefficient for urban surfaces

Coefficient Surface

0.85-0.95 Impervious paving or a building’s roof

0.2-0.75, average 0.35-0.55 Bare earth

0.05-0.35, average 0.1-0.25 Grass/lawn

(Source: Lancaster, 2010. Rainwater Harvesting for Drylands and Beyond Volume 2. Rainsource press. Page number 354)

The nine weather stations rainfall data taped from the NCEP site around Adama city arranged
in an excel sheet by their geographic coordinate and inserted into Arc GIS. The shapefiles
representing the stations and Adama city also inserted and using Thiessen polygons under
the Analysis tolls of Arc GIS the proximate weather station developed for the study area (fig.
3). Thiessen polygons divided the area covered by the stations to the proximal zones so
Adama represented by station five or Boset wereda.

23
 38°42'30"E 39°12'40"E 39°42'50"E

9°2'50"N

9 7 8
# # #

4 5 6
8°32'40"N

# Dhaka Adil
Goro
# #
14
05 Dabe Solloque
Elka Adama02
Boku Kebele

1 2 3
# # #
8°2'30"N

´ Kilometers
Legend
#
7°32'20"N

0 5 10 20 30 40 Weather station

Figure 3: Thiessen polygon

Annual Percentage cover of rainwater for non-potable water use was calculated by:

Formula 7:

𝐴𝑣𝑎𝑟𝑎𝑔𝑒 𝑝𝑒𝑟𝑠𝑜𝑛𝑎𝑙 𝑐𝑜𝑛𝑠𝑢𝑚𝑝𝑡𝑖𝑜𝑛 𝑣𝑜𝑙𝑢𝑚𝑒 𝑝𝑒𝑟 𝑑𝑎𝑦 (𝐿) × ℎ𝑜𝑢𝑠𝑒ℎ𝑜𝑙𝑑 𝑠𝑖𝑧𝑒 × 365 × 100
𝑝𝑜𝑡𝑒𝑛𝑡𝑖𝑎𝑙 𝑒𝑠𝑡𝑖𝑚𝑎𝑡𝑒𝑑 ℎ𝑎𝑟𝑣𝑒𝑠𝑡𝑒𝑑 𝑟𝑎𝑖𝑛𝑤𝑎𝑡𝑒𝑟 (𝑚3 ) × 1000

24
 Table 5: Summary of methods

No Specific objective Data used Source of data Collection method Instrument used Analysis

1 To identify Municipal water volume AWSSE Phone interview and phone Compute using
residential water used by the residents in Secondary data Standards
and residents
consumption m3 per day, month, and (customers report)
x̅ = ∑ 𝑥 /𝑁
patterns year for home use

𝜎=

√∑ (𝑥𝑖 − x̅ )2 /𝑁

2 To measure the Input water volume, Sampled Phone Interview Phone, bucket mean volume of
recycled water consumed volume, and residents water flow in the
volume. reused volume residents and WSC
index

3 To compute Residence water meter to Google Earth, Secondary data Computer catchment area(m2 )
Rainwater allocate their roof for area AWSSE, and (customers report), × runoff coffiecent
harvesting calculation, digitized NCEP weather and published × rain fall (mm)
capacity satellite image, and site literature sources × (0.001)
rainfall data = net runoff (𝑚3 )

25
3.5 Data Analysis

3.5.1 Residential water consumption pattern

The generated data from the administered interview and AWSSE customers report data
analyzed and simplified using Microsoft Excel (Excel 2013). The meter reading data analyzed
with the range of maximum and minimum, mean values, and standard deviation. The end-use
analysis includes consumption, hygiene, and amenity. The data is presented in a pie chart,
graphs of cluster column, line, Scatter plots, and simple tables to clearly show the result.

During the survey, the available indoor utilities with the volume of water consumption were
collected but toilet water consumption was analyzed using standards from the literature due to
the resident's uncertainty of the water used for toilet flush. The modern world strives for a
better life standard by minimizing effort and increasing comfort. These innovations perform in
the natural system using natural resources so studies have been developing in the integration
of these two polar with the minimum impacts one on another. The analysis comparatively
presents conventional methods to the modern way regarding resource consumption.

3.5.2 Recycled water use of Adama residents

The recycled volume of water used by residents who recycle water is estimated based on the
survey data; water used for the last rinsing of cloth and kitchen purpose. The mean volume of
water flow from the supply to the end disposal illustrated and in general, using the WSC index
the level of water recycling in the city was rated.

3.5.3 Rainwater harvesting capacity

To be sure about the rainfall, data tapped from NCEP from 1979-2008 (30 years) and a
Thiessen polygon was developed. The city falls in a polygon represented by station five (fig.
3). This data was used for estimating the amount of water harvested by each sampled house.
The mean annual rainfall for the years 1979-2008 is 804 mm. From the four climatic seasons,
keremt (summer) is the rainy period from (Jun-August) also there is an average rainfall in
Tseday (spring) in September. The average amount of rainfall in these three months is 200mm,
207mm, and 94mm, respectively (Refer to annex-4). The proportion of precipitation in these
three months is about 62.3% of the annual total. The built-up area was calculated for each
sampled plot and the total yearly harvested water volume has been calculated.

26
3.6 Research design

The analytical procedure of the research presented in (fig. 4)

Legend: Figure 4: Research design

Terminator

- Data

Process

Decision

27
 CHAPTER FOUR

RESULT

4.1 Residential water consumption pattern

I. Water availability
The availability of efficient water is the main concern of the modern world. From the surveyed
sample 19% of the residents used to get 24-hour water access, 23% (16 hours), 16% (pick
hour), and 42% of the residents used to get with schedule or day off but the supply in all the
above categories is not regular within the mentioned time boundaries it fluctuates (fig. 5).
Residents in Kebele 06, 07, 08, 12, 14, and 04 got an average of 18 hours/day of water access
whereas expansion areas (Boku Shana, Dhaka Adi, Dabe Sollogee, and Melkaa Adaamaa) got
intermittent supply with a schedule. The other kebeles got an average of 4 hours/day water
supply.

79 % of the residents use elevated storage and Jerrycans to store 1,000-5,000 liters for indoor,
outdoor, and emergency use.

19%

42%

23%

16%

24-hour access 16 hour access pick hour access other

Figure 5: Tap water availability

28
 II. Percentage volume of water consumed for indoor and outdoor uses

Residents use piped water almost for everything including cleaning their house compound,
gardening (small-scale farming and livestock), car washing, and toilet flushing. More water is
consumed for hygiene purposes 75.64 l/person/day (7 times the consumption water use 12.3L).
Under the hygiene category, cloth washing takes the largest percentage consumption (33.7%)
followed by toilet flush (24.7%) and bath (16.8%). The utility factors in the consumption of
the three hygiene categories have been explained below. The other is cleaning (9.2%) which
includes utensil, house, and compound cleaning. Drinking and cooking together consume 7.9%
of the total consumption. Gardening (5.5%) and other water use contribute 2.2% of the total
consumption (fig.6).

2.2%

5.5% 7.9%

16.8%
24.7%

9.2%
33.7%

drinking and cooking bathing cloth washing cleaning toilet gardening other uses

Figure 6: Average indoor water use in percentage

III. Water consumption by utilities

A. Toilet flush
Of the sampled residents 24.1% of the residents use only the squat toilet. This means 241
individual users. The rest of the 656 individual users use combined sitting and squat toilets. On
average the 241 individuals use 395.8 m3 of water annually for squat toilet flushing; 1.5L of
water used per flush with the frequency of three times a day and the 656 individuals use an
average of 2,772.6 m3 of water using 4.5L per flush three times a day (Table 6).

29
 Table 6: Volume of water used for toilet flush

Toilet type Households No of No of Average volume Volume of water

users flush per per flush (L)/day used annually
day (m3)

Pit toilet 49 241 3 4.5 395.8

Combined pit 154 656 3 1.5 2,772.6

and siting

B. Shower
The question survey includes only the bathtub and overhead shower but during the survey,
some respondents reply to the use of bucket water for shower. 85% of the residents use an
overhead shower with a range of 5-15 min duration and 1-5 times frequency per week. (Fig. 7)
present the total volume of water per liter calculated using a 7.5 average flow rate per min
(lpm).

800
Overhead shower water use per liter

700

600

500

400

300

200

100

0
5 min 10min 15min
Duration

once per week three times a week five times a week

Figure 7: Overhead shower water use by duration (min) and frequency per week

30
The duration and frequency of the shower are related directly to the volume of water used. 11%
of the residents take shower at average using10-20 liters of bucket water. Time duration doesn’t
affect the volume of water while using bucket water for the shower but the frequency per week
related directly to the total volume of water being used per week. Taking a 5min average
duration and frequency of 3 days per week 85% of residents use 1,092.4 m3 of water within 52
weeks of the year. 11% of the residents use 102.9 m3 of water annually with an average of 15
liters per shower (Table 7).

Table 7: Volume of water used for Shower

Shower Households in percentage (%) Volume of water used annually (m3)

By bucket water 15 284.9

Overhead 85 1,092.4

Duration: 5min, frequency: 3 times a week, flowrate: 7.5 l/pm

C. Cloth washing
Washing by hand takes energy, time, and labor compared to mechanical cloth washing but
consumes comparatively less water. The volume of the water washing machine used depends
on the type of machine. The mean volume of water used by the residents for cloth washing
using a washing machine is 115 L per wash load. 67% of the survey residents wash their clothes
by hand and the rest 33% of them use a washing machine. From the survey on average, a person
uses 25 - 40 L of water to washcloth. 67% of the residents consume 3,042 m3 annually with an
average of 32.5 L per wash three times a week whereas 33% of the residents using the washing
machine consume 5,289 m3 of water (Table 8). The statistics show washing machine users;
half of the residents who wash by hand with the same frequency per week consume a large
volume of water

31
 Table 8: Volume of water used to wash cloth

Cloth washing Households in percentage Volume of water used annually

technique (%) (m3)

By hand 67 3,042

Machine 33 5,289

IV. Family size and water consumption

A. Correlation
Household size and water consumption have a positive linear association (fig. 8). The volume
of water consumed is correlated (r = 0.88) to household size. The volume of water being
consumed increases as household size increases. (Refer annex 2&3)

0.7
Volume of water consumed (m3/day)

0.6 y = 0.05x + 0.13

R² = 0.77
0.5

0.4

0.3

0.2

0.1

0
0 1 2 3 4 5 6 7 8 9 10 11
Family size

Figure 8: Relationship between the volume of water consumed and family size

B. Mean water volume used per day

Table 9 relates household size with the meter reading volume of consumption. The SD shows
the range of water consumption volume within the same family size comparing to the mean
value. A low standard deviation indicates each household's water consumption volume tends
to be very close to the mean (family size 1) whereas a high standard deviation indicates that

32
the average volume of household water consumption is spread out over a range of value. (For
further detail refer to annex-1)

Table 9: Family size and water consumption

Demographic data Water consumption (m3/day)

Family size Number of Min Max Mean SD

households

1 7 0.04 0.16 0.15 0.14

2 13 0.14 0.23 0.19 0.02

3 29 0.22 0.30 0.26 0.04

4 68 0.32 0.42 0.36 0.03

5 53 0.39 0.46 0.43 0.02

6 14 0.43 0.55 0.47 0.04

7 6 0.44 0.52 0.47 0.03

8 6 0.49 0.56 0.53 0.03

9 4 0.54 0.57 0.55 0.02

10 3 0.53 0.58 0.56 0.01

C. Average monthly consumption

The monthly meter reading cubic water consumption data of the residents presented graphically
under (fig. 9). Relatively there is a higher consumption in March and April whereas minimizes
in August and September.

33
 -
volume of water (m3)
supplied to household
Volume of water (m3)

0
1
2
3
supplied to household 4

0
5
10
15
Jan
Jan Feb
Feb Mar
Mar Apr
Apr May
May Jun
Jun Jul
Jul

(a) Solo consumer

Aug
Aug
Sep

(d) Four consumer

Sep
Oct Oct
Nov Nov
Avarage water consumption (m3/month)

Dec

Avarage water consumption (m3/month)

Dec

volume of wate (m3)

Volume of water (m3) supplied to household
supplied to household
0
2
4
6
8

0
5
15

10

Jan
Jan Feb
Feb Mar
Mar Apr

34
Apr May
May Jun
Jun Jul
Jul Aug
Aug Sep
(b) Two consumer

Sep Oct
(e) Five consumer

Oct Nov
Avarage water consumption (m3/month)

Nov Dec
Avarage water consumption (m3/month)

Dec

Volumw of water (m3)

volume of water (m3)
supplied to household
supplied to household
0
2
4
6
8
10

0
5
10
15
20

Jan Jan
Feb Feb
Mar Mar
Apr Apr
May May
Jun Jun
Jul Jul
Aug Aug
(f) Six consumer

Sep Sep
(c) Three consumer

Oct Oct
Nov Nov
Dec
Avarage water consumption (m3/month)

Dec
Avarage water consumption (m3/month)
 volume of water (m3)
supplied to household
Volume of water (m3)

0
5
10
15
supplied to household

0
5
10
15
20
Jan
Jan Feb
Feb Mar
Mar Apr
Apr May

(j) Ten consumer

May
Jun
Jun

(g) Seven consumer

Jul Jul
Aug Aug
Sep Sep
Oct Oct
Nov Nov
Avarage water consumption (m3/month)

Dec

Avarage water consumption (m3/month)

Dec

volume of wate (m3)

supplied to household
0
5
10
15
20

Jan
Feb
Mar
Apr

35
May
Jun
Jul
Aug
(h) Eight consumer

Sep
Oct
Nov
Avarage water consumption (m3/month)

Dec
Figure 9: Monthly average water consumption by family size

volume of water (m3)

supplied to household
0
5
10
15
20

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
(I) Nine consumer

Sep
Oct
Nov
Dec
Avarage water consumption (m3/month)
4.2 Recycled water use of Adama residents

Only 12.65% of the households reuse the water used for the last cleaning of cloth for the pit
toilet cleaning and water used for cooking pasta, washing vegetables, and fruits for gardens.
From a total of 26 residents (124 individuals) 693.84 L of greywater is reused (Table 10).

Table 10: Volume of water reused by residents

Number of households Family size Volume of water reused L/day

5 3 94.08

9 4 229.32

6 5 164.64

3 6 86.3

2 8 50.9

1 9 68.6

87.35% of the residents expelled the tap water to the environment after a single-use. In
general, the consumption pattern of the surveyed residents is linear (fig. 10). There is no
recycling of used water.

Figure 10: Linear water flow per person per day

36
The current linear water metabolism of Adama city best fits rating 1 “no resource recovery
occurs” of the “optimized resource recovery” indicator for the ecological goal “improve
productivity & resource efficiency” of the WSC index.

4.3 Rainwater harvesting capacity

14 % of the sampled residents collect rainwater for day to day purpose of cleaning and
washing but they didn’t store it for future consumption. From the total residents who harvest
rainwater 79.6% of them found in the category of the residents with schedule or day-off tap
water availability. A total of 203 sampled residents cover a 20,199.4 m2 roof area and from
this, it is potentially estimated that a total of 15,428 m3 of water can be harvested annually
(Refer annex-1). Within rough estimation, it costs around 210,448.11 birrs with the current
Adama water tariff system (Refer annex-6).

Within the months of the rainy seasons, a total of 9,750.02m3 of water can be harvested from
the 203 sampled roof area (20,485.4 m2). It is possible to collect 3892.2 m3 in July, 4028.5
m3 in August, and 1829.3m3 in September (fig. 11).

Dec
Nov
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
Jan
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Potential estimated harvested rainwater in cubic meter

Figure 11: Monthly potential volume of rainwater

July, August, and September separately contribute 25%, 26%, and 12% respectively to the
total annual harvesting potential. Together the three months covers 62.3% of the total
rainwater that could be harvested annually (fig. 12).

37
 3.2% 1.5% 0.9% 1.1% 2.7%
5.8%

12.0% 7.0%

5.6%

10.0%
26.0%

25.0%

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 12: Monthly percentage contribution of rainwater harvesting potential

Fig 13 illustrates the potential estimated volume of rainwater that can be harvested from the
resident’s roof area. The volume of water harvested from the roof is directly related to the
roof area.

250.00
potential estimated harvested rain

200.00
water volume (m3)

150.00

100.00

50.00

0.00
0 50 100 150 200 250 300 350
Roof area (m2)

Figure 13: Potential estimated harvested rainwater volume

38
Annually harvested water from single households can entirely cover the non-potable water
demand of the residents (Table 11). As the family size increases the percentage demand cover
of the rainwater harvested decreases but still supports the demand and promotes
sustainability. The volume of harvested water depends on the roof area (fig. 13). (Refer
annex-7 for each household Annual % coverage of rainwater for non-potable demand)

Table 11: Potential support of Rainwater for potable water with family size annually

Family Number of Total roof Potential estimated Annual % coverage

size sampled area (m2) harvested rainwater for non-potable
households (m3) demand

1 7 533.6 407.6 101

2 13 953.2 728.1 48.5

3 29 2,064.9 1,577.2 31.4

4 68 7195.8 5,496.2 35.03

5 53 4393.5 3,355.9 21.9

6 14 2044.1 1561.3 32.2

7 6 726 554.5 22.8

8 6 1052 803.5 29

9 4 563 430 20.7

10 3 673 514 29.7

39
 CHAPTER FIVE

DISCUSSION

5.1 Residential water consumption pattern

Cities require natural resources for the survival of its population. According to the UN report,
cities occupy only two percent of the earth’s surface but consume over 75% of the natural
resource. Water is the main essential natural resource for cities. The growth and expansion of
cities with an increase in the inhabitants exacerbate the issue of sustainability. Metabolism
provides a metaphorical framework for the study of material flow, the interaction of a natural
and human system, and tracks the level of sustainability in cities.

The availability of water, utilities used at home, and the size of the family affect the volume
of water consumed by the residents. The distribution of water in the city is not equal. 42% of
the surveyed residents found water within schedule. Other than the 17% of the residents who
use bottled water for drinking the residents depend on the tap water supply for indoor and
outdoor activities so they collect when water is available using water tankers.

From the anthropogenic water uses hygiene takes the lion share by which cloth washing contributes
the largest percent 33.7 followed by toilet flush 24.7% and bath 16.8%. This implies the water that
passes through various levels of tests for drinking purposes is being used for hygiene. The volume of
water used for the three hygienic activities depends on the fixture type, frequency of the activity, and
time duration. For instance, the dual flush toilet provides an alternative volume of flush for liquid
waste and solid waste removal while older toilets use the same amount of water for both waste
removal. Modern world innovations only have a choice to be environmentally friendly as long as it
depends on nature. Specifically, toilets which are located indoor require regular cleaning unless it
could be a source of indoor air pollutant so water is the most essential element for the toilet. Squat
toilet consumes less water to remove waste than the western toilets and is very easy to clean it also
due to the lack of direct contact with the seat it’s more hygienic to share. The survey data shows
residents with sitting indoor toilets also have alternative outdoor squat toilets. Technological Fixtures
and Appliances used at home could help residents in daily life routines and give them extra comfort
but comparatively for the same amount of cloth the washing machine could take 50-100 liters of
more water than hand washing also washing water volume and frequency depend on the
family age composition, work exposure, and habit. As indicated in other researches (Arpke
& Hutzler, 2006; Wada et al., 2013) consumption intensifies the global water crisis.

40
Taking both the survey and volume of water used by residents the size of the household was
directly related to the volume of consumption. Currently, the water supply covers 78% of the
total water demand and 45% (10,132.82 ha) of the city master Plan by area. The supply is
expanded in the low laying areas which intensify water scarcity in the high laying zones. As
a level II city, the supply doesn’t satisfy the GTP II planed standard (80 l/c/d) also the
population is increasing at an exponential rate. Residence covers the largest percentage of the
land-use composition and is a place where life starts and flourish so it’s the primary line in
the supply system but due to the incompatible demand and supply and water-energy nexus
the resource becomes scarce. The recognition of sustainable approaches helps to manage the
ever-growing water scarcity.

Within the same family size, residents' utility utilization alters the volume of water being
consumed. Even though rainwater harvesting and greywater harvesting reduces demand for
tap water and promotes sustainability it does not contribute to a reduction in water
consumption so studying metabolism helps to identify the gap and promote efficient
utilization.

In general, the monthly consumption of the residents creates a pattern that flows throughout
the year with minimum fluctuation. Relatively there is higher consumption in March and
April whereas minimizes in August and September. Within the scarce supply diversified
water source than the centralized distribution system helps minimize the demand-supply gap
and also promotes sustainability.

5.2 Recycled water use of Adama residents

Circular metabolism aims to reuse or treat an outgoing resource as a new incoming resource
so the waste would be a resource instead of a problem. The pressure is on reducing water
demand by reducing wastage and reusing as much as possible. This helps to minimize or
reduce the impact of consumption in the environment and promote sustainability. Recycled
water has become a new alternative and reliable source of water in the cities. Wastewater has
been recognized by the UN through the world water development report as a resource
(Angelakis et al., 2018). Cities of the future improve today on sustainable models. Currently,
800 million peoples live under water stress predicted to be 3 billion in 2025 (Oteng-Peprah
et al., 2018).

41
The recycled use of water by the residents estimated by the end-use of water delivered to the
residents from the AWSSE. 12.65% of the residents reuse the water used for the last cleaning
of cloth and food preparation for the squat toilet cleaning, house compound cleaning, and
gardens. This helps to save tap water and use water resources to its maximum utilization level
rather than removing it from the system with limited uses. Compared to other cities around
the world with water recycling trends almost no one recycles water in Adama. The flow of
water is linear. Once the tap water was used, the quality diminished and become wastewater
and it was removed from the urban system. As a city which is struggling with supply
challenge consumption and removal are basic segments

The reuse of greywater is an old practice. Nowadays greywater reuse is an alternative water
supply in water stress areas (Oteng-Peprah et al., 2018). Greywater accounts for 75% of
wastewater which increases to 90% if a dry toilet is used. 14-116 liters of greywater generate
in Africa and the middle east, 75-225 L in Asia, and 123 L in the USA per person per day
(Oteng-Peprah et al., 2018). The generated greywater can be a source of water rather than a
waste to be removed by the means of recycling for compensating the growing water stress.
Currently, china increases the water reuse rate due to the water crisis (Zhu et al., 2018). In
Australia, the millennium drought (2000-2019) changes water reform policy to diversify
water source and secure continuous supply. This led to the expansion of recycling and the
provision of dual-pipe for drinking and recycled water (Radcliffe & Page, 2020).

By collecting the gray water, settling, filtering with natural charcoal and sand, and
disinfecting households can reuse wastewater and reduce potable water use by 25 - 30 %. The
use of recycled water for drinking, however, is less common, but a few countries like
Singapore, Australia, and Namibia, and states such as California, Virginia, and New Mexico
use recycled water for drinking (Menge, 1997).

5.3 Rainwater harvesting capacity

Rain is the major component of the hydrologic cycle and source of fresh water. Residents
depend on water supplies rather than using rainwater. Only 14% of the residents collect
rainwater for daily use but do not store it for future use. The development of cities changes
the natural landscape into impervious surfaces like roads and buildings. Such changes affect
the hydrology of the city and create runoff and flood. Rainwater harvesting can not only be a
source of water but reduce runoff, erosion, and can be stored for future use to compensate for

42
scarcity. It also increases water security by decentralized supply and reduces rural conflictive
invasion due to rural water sources cater to urban demand. Such sustainable practices are
being parts of the industrialized nations and urban areas (García Soler et al., 2018).

Roof-top water was a source of domestic water in small Islands in the Caribbean for more
than three Centuries and still, 500,000 peoples depend on it similarly 100,000 Jamaicans
depend on rainwater catchment. Honduras, Brazil, and Paraguay use rainwater as an
important source of water (Sendanayake, 2016).

From a total of 20,485.4 m2 roof area, it is potentially estimated that a total of 15,646.7m3 of
water can be harvested annually from 203 residences. By harvesting rainwater, residents can
support their Annual non-potable water demand. Australia is the driest inhabited continent
with the highest water use (300,000L) annually per household. In 2004 17% of the total water
source was rainwater. In southern Australia, 48% of households depend on rain for drinking.
From the ten most water-stressed countries Jordan with a low potential where 85% evaporates
back and 4% recharge the ground 5.6% of total domestic water supply can be meet by RWH
(Sendanayake, 2016). Within the blessed nature, rainwater is an unrecognized free resource
in Adama that can be harvested cheaply by the residents and can be used directly or with
further simple steps. It’s a lot for a city that is struggling to address the water demand problem.

In many countries to address water sustainability, Rainwater harvesting integration in new

buildings is enacted in law. US Virgin Islands, Sri Lanka, Bermuda, and Guinea-Bissau are
some of the countries that enacted RWH by law. Belgium enforces RWH system installation
and storm attenuation for buildings more than 100m2 roof area, Singapore mandates the RWH
system installation for new developments, and in Brazil, the government supports 1 million
RWH system installation to semi-arid areas. From east Africa Northern Kenya and Somalia
construct brick-lined large holes in the ground for water retention (Sendanayake, 2016). The
finding of the study compared to the global trend implies the vast work that should have to
be done in the sector of rainwater harvesting in residential buildings to support their water
demand. Promoting rainwater harvesting and developing water sensitive city fosters livability
and development in a sustainable base.

43
 CHAPTER SIX

FINDING, CONCLUSION, AND RECOMMENDATIONS

6.1 Finding

The municipal water supply is the main source of water in Adama city. The supply is
inconsistent where the largest volume of water is used for hygiene purposes (7 times the
consumption volume). Flush toilet takes (3times) water than a pit toilet. The volume of water
used for overhead shower depends on the shower duration and flow rate of the tap. The annual
volume of water used both by an overhead shower and bucket water depends on the frequency
per week. Washing cloth by machine takes (3.5 times) more water than washing by hand. In
general, the volume of water consumption is directly related to the size of the family in the
household. The average annual consumption of Adama residents relatively increases in April
and March and minimizes in August and September.

The water metabolism of the residents is linear. Within the rainy season (July to September)
it is possible to collect rainwater that can compensate for the non-potable use of residents
from their respective roofs.

6.2 Conclusion

Adama city is one of the fastest-growing cities in Ethiopia. This puts pressure on the water
supply along with poor management, increase demand with an increase in population and per
capita income, and less awareness of users towards environmental resource and consumption.
The projected population of Adama city in 2020 is 410,738 which will be 513,374 in 5 years.
The population residing in Adama is expected to exceed 1M in near future. Within the next
five years, the domestic water demand will grow from 19,971 m3/d to 27,017 m3/d. The
current upgraded system covers 78% of the total demand in which the production rate should
increase from 411 l/s (35,510.4 m3/d) to 511 l/s to satisfy the demand. Adama residents are
living under water scarcity. According to WHO 50l/c/d is an intermediate supply level, in
order to assure optimal supply minimum of 100 l/c/d should be supplied. 80l/c/d was the
service level aimed to be attained at the end of the GTP II but the current supply is 48.6 l/c/d
(Refer annex-5). Only increasing production rate couldn’t coup up with the exponentially
growing demand. Understanding the end-use of water helps in focusing on conservation
methods that are financially and environmentally acceptable.

44
There is no recycling of water by the Adama residents. The critical resource is discarded
without any further use also 84% of the total water demand, is used for non-potable usages
such as hygiene and amenity uses. The municipal water line is the only water source for the
residents so the scarce treated water is being used for non-potable purposes while drinking
water is the question of many other peoples.

Adama residents can support their non-potable water demand by harvesting rainwater and
reusing greywater but such sustainable approaches are neglected both by the officials and
residents.

6.3 Recommendation

 Understanding consumption and applying demand-side management rather than

exploiting a new resource should be done to address the demand-supply gap and
promote sustainability.
 Environmental issues need to be centralized with knowledge, research, and awareness.
The overall process should be supported with such studies, awareness‐raising, and
education which are very important for changing the current trend and develop a
sustainable society. This needs to be addressed by media, governmental, and non-
governmental institutes working on the water sector by organizing public awareness
programs. Evolving environmental consciousness in society is the key to a change.
 Adama residents should have to be aware of the importance of; appropriate fixtures
choice for home, efficient water consumption habits, roof water harvesting systems,
and water recycling to be sustainable enough.
 The tap water passes through a variety of disinfecting stages to remove all the potential
hazards for human health and wellbeing which consumes resources such as; energy,
finance, and time; therefore the non-potable use of water should have to be offset by
harvesting rainwater and reusing greywater.
 Tariff adjustment should be done for those who used rainwater and offset most of their
potable water demand from the municipality.
 AWSSE should develop strategies for the application of sustainable approaches like
rainwater harvesting and greywater reuse and implement it to support the demand-
supply gap.
 The integration of a rainwater harvesting system in the Architectural design of
residential buildings should be enacted in law.

45
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APPENDIX-1

ADAMA SCIENCE & TECHNOLOGY UNIVERSITY-(ASTU); Kebele

Department of Architecture, Post Graduate Program/ MSc in Environmental Architecture Block no.

Domestic water Use of Adama residents surveying form Date

Demography Meter serial number

o Family size

Water Availability Scarce Efficient Water Availability per day

24 hr.
Average Water use per litter per person per day
16 hr.
o Consumption
Peak hour
Drinking Cooking Other
o Hygiene
Toilet flush
Bathing
Gravity Fed Toilet Flush toilet
Teeth washing
Bathing
Hand and face cleaning Bath Tub Shower head

Cloth washing Frequency per day Time duration

Cloth washing
Utensils washing
Washing machine manually
House cleaning

Toilet flush

o Amenity

Gardening Car washing Other use

Rain water harvesting

o Did you collect Rain Water? Yes No

o For wat purpose do you use the rain water?

Consumption Hygiene Amenity
o Roof area
Waste water treatment
o Did you recycle water? Yes No
o For what purpose do you use the waste water

Water storage
What Volume of water did you store? Tanker size

51
Annex 1. Consumption data

52
53
54
55
56
57
58
59
Annex 2: Correlation “r”

x̅ = 5.5, ̅y = 0.4, SDx = 3.03, SDy = 0.15

X Y ZX ZY ZXZY

1 0.15 -1.49 -1.64 2.43

2 0.19 -1.16 -1.38 1.60

3 0.26 -0.83 -0.87 0.72

4 0.36 -0.50 -0.27 0.13

5 0.43 -0.17 0.18 -0.03

6 0.47 0.17 0.43 0.07

7 0.47 0.50 0.49 0.24

8 0.53 0.83 0.86 0.71

9 0.56 1.16 1.07 1.24

10 0.57 1.49 1.11 1.65

Avg. ZXZY, r =0.88

X: household size, Y: volume of water consumption

Formula: 8

(xi − x̅) (yi − y̅)

zxi = zyi =
SDx SDy

R2 = 0.77

60
Annex 3: Linear Regression Equation

NO X Y XY X2 Y2

1 1 0.15 0.15 1 0.02

2 2 0.19 0.37 4 0.03

3 3 0.26 0.79 3 0.07

4 4 0.36 1.43 16 0.13

5 5 0.43 2.13 25 0.18

6 6 0.47 2.80 36 0.22

7 7 0.47 3.31 49 0.22

8 8 0.53 4.23 64 0.28

9 9 0.56 5.06 81 0.32

10 10 0.57 5.68 100 0.32

Total 55 3.98 25.93 385 1.79

Formula: 9

(∑ 𝒚)(∑ 𝒙𝟐 )−(∑ 𝒙)(∑ 𝒙𝒚) 𝒏(∑ 𝒙𝒚)−(∑ 𝒙)(∑ 𝒚)

a = 𝟐 b = 𝟐
𝒏(∑ 𝒙𝟐 )−(∑ 𝒙) 𝒏(∑ 𝒙𝟐 )−(∑ 𝒙)

a = 0.13 b = 0.05

y = a + bx

y = 0.13 + 0.05X

Annex 4: Annual rainfall and average monthly and annual rainfall in mm

The weather station is located at 39.375 longitudes, 8.586 latitudes, and 151 elevations.

Using the Arithmetic mean method;

Average annual rainfall = total annual rainfall/period (30 years)

Average annual rainfall = 804

61
 Annual rainfall
160
Precipitation (mm) 140
120
100
80
60
40
20
0
1980

2006
1979

1981
1982
1983
1984
1985
1986
1987
1988
1989
2000
2001
2002
2003
2004
2005

2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
Year

Annual precipitation (mm)

Annual rainfall in mm

July, August, and September are the wettest months of the year. December is the month
with the lowest rainfall.

Monthly avarage rainfall

250
200 207
200
Precipitation (mm)

150

94
100 79
47 56
45
50 26
22
9 12 7
0
Jan Feb Mar Apr May jun Jul Aug Sep Oct Nov Dec
Month

Rainfall in mm

Average monthly rainfall in mm

62
Annex 5: per capita water supply calculation

From the total daily production of water 63% (19,971 m3/d) supplied to residences. The per

capita water supply (l/c/d) calculated for 410,738 population as:

Formula 10:

𝑑𝑎𝑖𝑙𝑦 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 (𝑚3 ) × 1000𝑙/ 𝑚3

𝑝𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛 𝑛𝑢𝑚𝑏𝑒𝑟

Annex 6: Adama city current water tariff

Water tariff

Block Range Birr/ m3

1st 0-5 m3 6.85

2nd 6-10 m3 7.80

3rd 11-15 m3 10.70

4th 16-20 m3 11.95

5th >20 m3 13.45

(Source: Adama water supply, sanitation, and sewerage enterprise)

63
Annex 7: correlation between potential estimated harvested rainwater and percentage offset for non-potable water use with family size
150 200

percentage offset of potabel

harvested rain water (m3)

150 150

percentage offset of
harvested rain water (m3)
150
Potential estimated

100
100 100

Potential estimated

potabel water
100
50 50 50 50

water
0 0 0 0
1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 10 11 12 13
No of households No of households

Potential estimated harvested rain water (m3) Potential estimated harvested rain water (m3)
percentage offset of potabel water percentage offset of potabel water

(a) One family households (b) Two family households

150 (b) 80 400 150

percentage offset of potabel

percentage offset of potabel

harvested rain water (m3)

harvested rain water (m3)

60 300
Potential estimated

Potential estimated
100 100
40 200
50 50
20 water 100

water
0 0 0 0

13
17
21
25
29
33
37
41
45
49
53
57
61
65
1
5
9
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
No of households
No of households

Potential estimated harvested rain water (m3) Potential estimated harvested rain water (m3)
percentage offset of potabel water percentage offset of potabel water

(c) Three family households (d) Four family households

1.
64
 200 60 250 60

percentage offset of potabel

percentage offset of potabel

Potential estimated harvested

Potential estimated harvested

50 200 50
150
40 40
150
rain water (m3)

rain water (m3)

100 30 30
100

water

water
20 20
50
10 50 10
0 0 0 0
10
13
16
19
22
25
28
31
34
37
40
43
46
49
52
1
4
7

1 2 3 4 5 6 7 8 9 10 11 12 13 14
No of households
No of households
Potential estimated harvested rain water (m3) Potential estimated harvested rain water (m3)
percentage offset of potabel water percentage offset of potabel water

(e) Five family households (f) Six family households

2.
150 40 250 50

percentage offset of potabel

Potential estimated harvested

percentage offset of potabel

Potential estimated harvested
30 200 40
100
150 30
rain water (m3)

20

rain water (m3)

50 100 20

water

water
10 50 10
0 0 0 0
1 2 3 4 5 6 1 2 3 4 5 6
No of households No of households

Potential estimated harvested rain water (m3) Potential estimated harvested rain water (m3)
percentage offset of potabel water percentage offset of potabel water

(g) Seven family households (h) Eight family households

3.
65
 160 30 350 60

percentage offset of potabel watere

Potential estimated harvested rain

percentage offset of potabel water

Potential estimated harvested rain water

140 300
25 50
120
250
20 40
100
200
water (m3)

80 15 30
150
60

(m3)
10 20
40 100
5 50 10
20
0 0 0 0
1 2 3 4 1 2 3
No of households No of households

Potential estimated harvested rain water (m3) Potential estimated harvested rain water (m3)
percentage offset of potabel water percentage offset of potabel water

(I) Nine family households (j) Ten family households

4.

66