Final Submission - Ndolo. F.

UNIVERSITY OF NAIROBI

Feasibility Study for a Community Water Project in

Misuuni, Machakos County

By Ndolo Festus Kavita, F16/1288/2010

A project submitted as a partial fulfilment for the requirement for the award of

the degree of

BACHELOR OF SCIENCE IN CIVIL ENGINEERING

2015

Abstract

Water is crucial not only for sustaining life but also for socio-economic development of a

community. Its availability in the right quality and quantity at the required time and space

remains a great challenge. This is more so evident in rural areas in Kenya. In this particular

report, focus was on Misuuni area in Machakos County. Before embarking on a water

project, it is crucial to know its impacts and assess the feasibility of meeting the objectives

without any major drawbacks. This particular study sought to find out the ability of the

proposed water supply system to sufficiently provide water to residents, institutions and

businesses in the area.

Misuuni experiences 5-6 months of continuous dry weather and in some instances years of

continuous dry periods. Currently, good resource management practices like the Integrated

Water Resources Management Approach (IWRM) adopted by the Kenyan government

demand participation of users including communities in the decision making processes

concerning the water resources. Therefore, the study consulted various stakeholders in the

community seeking their input on various issues. Their input was key in investigating the

water supply situation and assessing its strengths, as well as highlighting its downfalls and

suggesting appropriate counter measures to ensure that the residence of the study area receive

sufficient and safe water supplies. This study was conducted using a mix of methods i.e.,

simple tests (water quality), door to door interviews with residents, administering

questionnaire to the water users.

The options considered were; the drilling of a new borehole with water kiosks at different

points in the community, the abstraction of water from existing sources with basic treatment

where required and the use of rain water catchment as a supplement to the water supply

system. Feasibility was considered according the ability to meet the legal requirements, water

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quality standards, provision of the quantity demanded and acceptability by the community.

After analysis of the existing systems, laboratory tests and calculations. Based on all the

results, the study recommended the use of rain water catchment as an initial short-term

mitigation followed by the rehabilitating of the existing sources by treating dam water by

slow sand filtration system, optimization of Manos Unidas borehole and incorporation of

Patrick Mailang’a’s borehole in the public supply system by with a water supply system to

various water kiosks.

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Dedication

This project is dedicated to the Misuuni community, for they understand the struggles of

living without adequate water. The output of this project will have a direct impact in their

life.

I also dedicate my work to my family who have provided support, both in material and in

person in undertaking this project. They have helped collect samples, administer

questionnaires and with general research concerning the area.

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Acknowledgements

I would like to acknowledge, first of all, the input of my supervisor, Eng. Gitonga, in the

course of doing this project. His guidance has been crucial in doing this project.

Also, the help of Ms. Wambui of the Environmental Health laboratory cannot go without

note. Her assistance in conducting the qualitative analysis of the various water samples was

very important in the completion of my work.

I would finally like to acknowledge the input of my lecturers throughout the five years of my

civil engineering undergraduate program at the University of Nairobi. The various things I’ve

been taught have been helpful in completing this project.

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Table of contents

1. INTRODUCTION ............................................................................................................ 1

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

1.2. Definition .................................................................................................................... 2

1.3. Objectives .................................................................................................................... 3

2. METHODOLOGY ........................................................................................................... 4

2.1. Desk Study .................................................................................................................. 4

2.2. Reconnaissance stage .................................................................................................. 4

2.3. Fieldwork stage ........................................................................................................... 5

2.4. Analysis ....................................................................................................................... 5

3. EXISTING CONDITIONS .............................................................................................. 6

3.1. Physical Conditions ..................................................................................................... 6

Location .............................................................................................................................. 6

Topography ......................................................................................................................... 6

Climate................................................................................................................................ 7

3.2. Socio-Economic Conditions ........................................................................................ 7

Population ........................................................................................................................... 7

Administration .................................................................................................................... 7

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Institutions .......................................................................................................................... 8

Commercial centres ............................................................................................................ 9

Physical infrastructure ........................................................................................................ 9

Willingness to pay for water ............................................................................................... 9

Diseases [waterborne] ....................................................................................................... 10

3.3. Existing water supply condition ................................................................................ 11

Rivers ................................................................................................................................ 11

Earth dams ........................................................................................................................ 12

Boreholes .......................................................................................................................... 14

Rainwater Collection ........................................................................................................ 16

3.4. Existing Demand ....................................................................................................... 19

Institutional Demand ........................................................................................................ 19

Commercial Demand ........................................................................................................ 20

Domestic demand ............................................................................................................. 20

3.5. Existing Quality......................................................................................................... 20

4. ANALYSIS ...................................................................................................................... 28

4.1. Water Demand Projections........................................................................................ 28

Domestic Consumption Projection ................................................................................... 28

Commercial Demand Projections ..................................................................................... 29

Institutional Demand Projections ..................................................................................... 29

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Demand vs Supply Deficit ................................................................................................ 30

4.2. Overview of Options ................................................................................................. 32

Borehole Drilling .............................................................................................................. 32

Utilization of Existing Water Resources .......................................................................... 33

Rainwater Collection as Supplement ................................................................................ 35

4.3. Evaluation of Alternatives ......................................................................................... 36

Option 1; Drilling a New Borehole .................................................................................. 39

Option 2; Rehabilitation of Existing Resources ............................................................... 41

Option 3; Rain Water Collection as Supplement .............................................................. 46

5. CONCLUSION AND RECOMMENDATIONS.......................................................... 50

5.1. Conclusion ................................................................................................................. 50

5.2. Recommendations ..................................................................................................... 51

Capacity of Works ............................................................................................................ 51

Time of Implementation ................................................................................................... 51

Operation and Maintenance Requirements ....................................................................... 52

Cost of Implementation .................................................................................................... 52

Selected Alternative .......................................................................................................... 53

6. REFERENCES ............................................................................................................... 54

APPENDIX A: LABORATORY TESTS ................................................................................ 56

APPENDIX B: QUESTIONNAIRE ........................................................................................ 60

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APPENDIX C; Manos Unidas Borehole Usage Log ............................................................... 66

APPENDIX D; Water Quality Standards (EMCA) ................................................................. 67

APPENDIX E; Independent Test Results ................................................................................ 68

APPENDIX F; WRMA FORMS ............................................................................................. 69

APPENDIX G: MAP OF THE PROPOSED BOREHOLE PLUS SUPPLY SYSTEM ......... 82

APPENDIX H; Quotation for borehole drilling ...................................................................... 84

APPENDIX I; Photos .............................................................................................................. 87

APPENDIX J; SSFs - FURTHER DETAILS .......................................................................... 90

APPENDIX K; Hydro-geological survey report for proposed borehole site .......................... 92

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Table of Figures

Figure 3-1 Map of the project area ............................................................................................ 6

Figure 3-2 Water Source - Consumption. ................................................................................ 17

Figure 3-3 Water Retrieval Difficulties. .................................................................................. 17

Figure 3-4 Retrieval Demographics ......................................................................................... 18

Figure 3-5 Water Consumption - Agriculture. ......................................................................... 18

Figure 3-6 Volume of Water Stored ........................................................................................ 19

Figure 3-7 Reported Waterborne Illness. ................................................................................. 21

Figure 3-8 Particles Present in Water ...................................................................................... 22

Figure 3-9 Percentage of Homesteads That Treat Their Water ............................................... 22

Figure 3-10 Drinking Water Descriptions ............................................................................... 23

Figure 3-11 Filtration Methods Used for Water Treatment ..................................................... 23

Figure 3-12 Water Quality Reference. ..................................................................................... 23

Figure 4-1 WRMA water permit application process .............................................................. 38

Figure 6-1Illustration of a slow sand filter with a regulating valve and a subsequent reservoir

.................................................................................................................................................. 91

Figure 6-2 Principle of a slow sand filter................................................................................. 91

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List of Tables

Table 3-1 Institutional demand of water per day ..................................................................... 19

Table 3-2 Commercial demand per day ................................................................................... 20

Table 3-3 Laboratory results for Kathaana River water sample .............................................. 24

Table 3-4 Laboratory results for Kathuku Dam water sample ................................................ 25

Table 3-5 Laboratory results for Misuuni Dam water sample ................................................. 25

Table 3-6 Laboratory results for Miumbuni Secondary School Borehole water sample ........ 26

Table 3-7 Laboratory results for Phillip Ndolo Treated Water sample ................................... 26

Table 3-8 Laboratory results for Lazarus’ homestead rain water sample ................................ 27

Table 3-9 Laboratory results for Manos Unidas Borehole water sample ................................ 27

Table 4-1 Population projections ............................................................................................. 28

Table 4-2 Domestic water demand projections ....................................................................... 29

Table 4-3 Commercial water demand projections ................................................................... 29

Table 4-4 Commercial water demand projections ................................................................... 30

Table 4-5 Summary of Water Demand Projections ................................................................. 30

Table 4-6 Summary of demand and supply deficit .................................................................. 31

Table 4-7 Typical treatment performance of slow sand filters. ............................................... 43

Table 4-8 Breakdown of cost for ground water options .......................................................... 44

Table 4-9 Revenue from water sales ........................................................................................ 44

Table 4-10 Breakdown of costs for filtration plants ................................................................ 45

Table 4-11 Revenue from sale of treated water ....................................................................... 46

Table 4-12 Quantity supplied by roof catchment vs demand .................................................. 47

Table 4-13 Cost estimations for Rain water harvesting ........................................................... 48

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Table 4-14 Comparative costs after Rain water system........................................................... 49

Table 5-1 Demand vs Supply Conclusion ............................................................................... 50

Table 6-1 Independent Test Results by EWB-USA team ........................................................ 68

Table 6-2 Features of SSFs ...................................................................................................... 90

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List of Abbreviations

APHA American Public Health Association

AWWA American Water Works Association

CBO Community Based Organization

EDTA Ethylenediamine Tetraacetic Acid

EMCA Environmental Management and Coordination Act

EWB-USA Engineers without Borders, United States of America

FTU Formazin Turbidity Unit

NTU Nephelometric Turbidity Units

O&M Operations and Maintenance

pH Pondus Hydrogenium

PHE Public Health Engineering

ppm parts per million

TDS Total Dissolved Solids

TSS Total Suspended Solids

UNESCO United Nations Educational, Scientific and Cultural Organization

WHO World Health Organization

WRMA Water Resources Management Authority

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List of Symbols

mg CaCO3/L Calcium Carbonate in milligrams per litre

mg Cl/L Chloride in milligrams per litre

mg F/L Fluoride in milligrams per litre

mg Fe/L Iron in milligrams per litre

mg TSS/L Total Suspended Solids in milligrams per litre

mg TDS/L Total Dissolved Solids in milligrams per litre

1. INTRODUCTION

1.1. Background

Water is a basic human need. Life depends on the availability of water. However, it is not

just about the availability but also the characteristics of the water that matters the most. For a

proper life, water must be available of good quality and sufficient quantity. Quality standards

are globally set by WHO and locally in Kenya set as per the EMCA act of 2006. Quantity

needs are determined by the user’s need.

In Kenya’s rural areas, water availability in quality and quantity is a major problem. The

sessional paper no. 1 of 1999 on national water policy on water resources management and

development provided the policy direction to address these challenges. The Water Act 2002

birthed from this paper was developed with the principles such as to equitably allocate water

for all Kenyans and acceleration of supply and distribution of water in rural areas through

special funding. Misuuni area in Machakos County is one such rural area in need of a water

supply system.

The Machakos County government had set among its development priorities, the need to

provide water to every household. This, as stated in their goals, was to be done by drilling

boreholes, digging water pans and developing existing water resources. Since the task was

expensive, the county government sought to achieve this goal in conjunction with donors and

community groups. Misuuni area was a benefactor of such, through donor funding from

EWB-USA for a water supply project in conjunction with Misuuni Self Help Group. The

project sought to provide safe drinking water to the community by drilling a borehole. It also

sought to find enough water to irrigate the land. Therefore, a feasibility study was required to

establish the viability of the borehole idea, find out alternatives and to recommend the

appropriate action to be taken.

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1.2. Definition

A feasibility study is a thorough evaluation of a proposed activity undertaken in order to

formulate a description of the most desirable actions to be taken. Feasibility of a project

implies that it will effectively serve its intended purpose without any serious negative

impacts. The feasibility of a project is measured by specifying the project objectives and also

specifying the notes for measuring success. Generally, feasibility studies precede technical

development and project implementation. Perceived objectivity is an important factor in the

credibility of the study for potential investors at lending institutions. It must therefore be

conducted with an objective, unbiased approach to provide information upon which decisions

can be based.

In this specific case, the objective was to find out whether the proposed water supply

proposals could sufficiently supply water of desirable quality and quantity. The specific

objectives of the water supply project were;

(i) Provision of sufficient drinking water to residents of Misuuni area throughout the

year.

(ii) Provision of water for irrigation within Misuuni area.

The potential negative impacts were:

(i) Expense in implementation

(ii) Low uptake by residents

(iii) Environmental deterioration

The rules of measurement of the success of the project were:

(i) Water Quality – The water quality must confer to the required standards.

(ii) Water Quantity – The project must supply enough water for the desired uses.

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(iii) Economy – The recommended course of action must be within the budget cap

of the donor and also have operation economic value.

(iv) Legal feasibility – The prepared system should not conflict with legal

requirement and must also meet the required legal steps.

1.3. Objectives

With such objectives of the water supply project stated, and the rules of measurement of

achievement specified, the objectives of this feasibility study were;

(i) Survey of existing conditions

(ii) Analysis of suggested course of action

(iii) Analysis of alternatives

(iv) Recommendation of course of action

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2. METHODOLOGY

In order to achieve the set objectives, there were a number of stages required. In the case of

this study they were;

(i) Desk study

(ii) Reconnaissance

(iii) Fieldwork

(iv) Analysis

The specifics of these stages are stated below:

2.1. Desk Study

In this stage, available information was obtained from relevant websites/organizations and

studied. This involved;

Studying the map of the area

Studying the legalities undertaken for a water supply project.

Obtaining online information pertaining to this specific project and also general data

on such a project.

Planning on the steps to be taken in accomplishing this study

2.2. Reconnaissance stage

This involved an initial visit to the Misuuni area. Its purpose was to identify the aspects that

need further study and eliminate options that are obviously infeasible. This involved:

General survey of the study area

Familiarisation with authorities/stakeholders

Determination of equipment needed in further data collection

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2.3. Fieldwork stage

This was a thorough visit to the area and to the pertinent authorities. It was a much more

detailed study of existing conditions and obtaining of the data needed for further analysis.

The actions undertaken here were:

(i) Mapping of area; by photography and obtaining maps

(ii) Mapping suggested water points

(iii) Analysis of topography

(iv) Questionnaires – These were given to schools and hospitals for data on school

attendance and hospital records

(v) Interviews; These were done as listed below;

Households - Household surveys were conducted related to the entire

homestead. Twenty homesteads were surveyed, with a total of 249 individuals

represented in the survey. This consists of about 12% of Misuuni’s population

(about 2000 people).

Farms

Community groups

(vi) Sampling - For laboratory purposes, samples of water were taken. These were

done by use of sampling bottles from PHE lab of the University of Nairobi.

2.4. Analysis

The acquired data from the above studies was analysed in this section of work to obtain

useful information in regards to the study. This involved further studying of the maps,

tabulating the laboratory results, selection of appropriate photos and calculations based on

obtained data. Then, conclusions were made from the analysed data.

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3. EXISTING CONDITIONS

Before any course of action was considered it was key to analyse the study area. The existing

conditions surveyed in this study were divided into these categories:

(i) Physical conditions

(ii) Socio-economic conditions

(iii) Water supply conditions

These categories were studied as follows:

3.1. Physical Conditions

Location

Misuuni village, is located in Kathiani Sub-county of Machakos County. It is located about

40 km from Machakos town and 70 km from Nairobi.

Topography

Below is a map from Survey of Kenya, dated 1976 and although it is a bit outdated, it depicts

the vertical profile more accurately.

Figure 3-1 Map of the project area

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The area enclosed by the red envelope shows a rough boundary of the area under study.

Altitude data from the map indicates that the highest point is 1460 meters above sea level and

the lowest is 1400 meters above sea level. The area generally slopes outwards to the rivers,

with several streams feeding into the rivers through valleys. The earth dams are located at the

mouths of the major valleys

Climate

According to the Agro-climatic map of Kenya (Braun, 1980) the climate of the study area is

semi-humid to semi-arid zone (zone IV to V), characterized by a low, bi-modal rainfall and

high evaporation. The total average annual rainfall can be estimated to be in the range of 450

mm to 600 mm which falls mainly during two distinct rainy seasons. The long rains are

expected between March and May and the short rains between October and December.

The mean monthly temperature varies between 22◦C and 28◦C. July is the coldest month

while October and March are the hottest.

3.2. Socio-Economic Conditions

Population

The estimated population during the study period was around 2,000 scattered over an

estimated area of 6 kilometres long by 3 kilometres wide, and dispersed on either side of a

central dirt road bisecting the village area. The households were fairly distributed with a few

clustered areas.

Administration

The area is governed by Machakos County Government. It’s within the jurisdiction area of

Kathiani Sub-County. Water-related activities are coordinated through the sub-county water

engineer in Kathiani.

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There is one police post in Miumbuni.

Institutions

There were five schools in the area. These were;

(i) two public primary schools,

Misuuni Primary School

Miumbuni Primary School

(ii) two private primary schools

Miumbuni AIC Junior Academy

Miumbuni Preparatory Academy

(iii) a public secondary school

Miumbuni Secondary School

The local dispensary, Miumbuni Dispensary, was the only medical institution in the area. It

served an average of 50 patients per day and used an average of 350 litres per day.

Miumbuni Primary School Survey.

This is one of the schools visited during the study to investigate and understand the impact of

water scarcity on the day to day life of the students in school. From the school attendance

record about 10-20 students per day were absent, with a large percentage of them speculated

to be due to water-borne diseases. The principal confirmed that about 100 students are out of

school at least once in a term due to water borne diseases. Generally, an hour or two is wasted

daily by the majority of the students so that they can travel to retrieve water for the school

and their homestead. Also, it was discovered that the school barely has enough water to keep

it running efficiently.

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Commercial centres

There were three markets in the area; Miumbuni, Misuuni and Musaalani. Each had a few

businesses that used water. The major consumers of water in the markets were hotels,

butcheries and bars. The local shops mainly used water for basic cleaning of facilities.

There were a few private agricultural farms that relied entirely on irrigation from rivers, earth

dams and boreholes. The amount of water used and the method of supply for these were

studied.

Physical infrastructure

Power supply

The area is fairly connected to the power grid though the uptake is distributed mostly to

commercial businesses that require electricity. Only a few homes are connected.

The hospital and secondary school are connected. Solar power and generators are commonly

used. Solar power must be considered.

Willingness to pay for water

Generally, 40% of the population were already paying for drinking water especially during

the dry season. Only those with the means, about 10%, would pay for irrigation water.

Uptake depended on viability in terms of profit and not most residents were entrepreneur-

minded. They would rather fetch from rivers near the farms than pay for water for irrigation.

This meant that during the dry season, most farms would lay idle.

The institutions were willing to pay for water because they are funded by the government and

it’s a basic need for operation.

Businessmen were willing to pay if it improved profitability.

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Diseases [waterborne]

A portion of the survey also asked about water quality and the homesteads’ experience with

sickness. Moreover, inquiries were made at the local clinic about their records. In regards to

health, 85% of the homesteads surveyed have experienced sickness due to the water and out

of those individuals, 82% reported that they have experienced sickness that was severe

enough to keep them out of school or work for a significant amount of time (on average 16

days). According to the surveys conducted at the school in Misuuni, there was a reported 100

absences per term.

The primary source of healthcare for people in Misuuni, besides the local dispensary, is the

Kathiani Hospital, which is significantly far from most of the homes, such that is accessibility

to the hospital is an adverse task. It is located about 5 km from Misuuni. Moreover, the

nearby health dispensary can only accommodate two patients at a time (mostly maternity

patients). A survey conducted at Kathiani Hospital and at community dispensary delineated

that the most common cause of these illnesses is due to the wide usage of contaminated water

in drinking, cooking, and domestic use. It was reported that in the six to twelve months

previous to the study, cases of bilharzias, diarrhoea, bloody diarrhoea, and leishmaniasis had

been received. At the dispensary, 300 of the patients received were under the age of five,

while 200 of the patients they received were over the age of five. The dispensary served

about 50 people per day and used about 250 litres of water daily. It was reported from

surveys that the peak season for diarrhoea cases included the dry season (around August to

late September) and the harvest season (around March to May). This appears to corroborate

the aforementioned data stating that the water during the dry season is of a poorer quality.

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3.3. Existing water supply condition

The existing water sources were divided into the following categories;

(i) Rivers

(ii) Earth Dams

(iii) Boreholes

(iv) Rainwater Harvesting

Rivers

There were two rivers in this area which actually run along the border lines of the study area.

These rivers were Muvaa and Kathaana. Both of these rivers were seasonal. They had

flowing water for four months annually. There were stagnant ponds within the rivers that

lasted for about two months after river flow had ceased. The rivers had bridges without

culverts hence trapping water behind them to form temporary reservoirs that in some cases

could hold water for up to four months in a year.

River water was mainly used for irrigation of adjacent farms and for animals. However, some

families that lived nearer to the river than other water sources, opted to use river water for

domestic purposes because of the long distances and also, because of ignorance of the

potential impacts of using such water for domestic purposes.

Kathaana River

This river is on the Eastern side of the area under study. There was no existing data on river

flow quantities. Based on interviews, the river usually flows for about four months in a year,

during the rainy season. There was only one bridge reservoir along this river. This was the

only watering point considered in the study. It was designated as Mutanda, which is the local

name used for it.

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At Mutanda, water had three uses; livestock use, irrigation of adjacent farms and domestic

use. Livestock use was the most common use, as was also for all the other water points along

this river. Irrigation was the secondary use. The farms were small scale and the average size

of a farm was one acre. The main crops irrigated were vegetables, for both subsistence

purposes and small-scale commercial purposes. Sometimes the water was used for domestic

purposes.

From the field study, water samples were taken and laboratory tests conducted to assess the

water quality.

Muvaa River

This river flows along the western boundary of the study area. There was also no existing

data on flow quantities. Based on interviews, the river flows for about six months in a year.

There were three bridges and only two had reservoirs. Therefore, only these two were

considered for further study and water-sampling. They were designated as Kithuka and

Kithanze water points. The reservoirs at both points were quite small so they only held water

for about one month after river flow ceased.

Water from both points was mainly used for livestock, irrigation of adjacent farms and for

domestic purposes.

Earth dams

These are whereby earth embankments are constructed to trap run-off water and create a

reservoir. In the study they were categorized into two;

(i) Public dams

(ii) Private dams

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The earth dams retained water longer than the rivers and the water was also observed to be

cleaner, during the rainy season but the quality would deteriorate during the dry season.

However, they would still dry up due to insufficient rainfall coupled with a growing demand.

Water was fetched directly from the dam either by hand-carried containers, or transported on

bicycles, wheelbarrows and animal driven carts.

All the public dams were studied and two of the private dams were randomly selected as

representative samples.

Public Dams

There were three public earth dams in this area namely,

a) Misuuni,

b) Kwa-Kathuku

c) Kwa-Lazarus

They were situated near the markets and were fairly accessible. However, there is a

significant percent of the populace who live quite a distance away from the dams.

Water from these dams was used for domestic purposes, agriculture, in schools and for

businesses. Only Kathuku dam was used for livestock drinking because of the lack of an

alternative source for that. For the others, livestock drinking was prohibited because there

were rivers nearby for such purpose.

For each of the dams, measurements were taken to calculate the capacity and water samples

for laboratory analysis of the water quality.

Kwa-Lazarus dam had been recently constructed by the county government and started

functioning in October 2014 when rains started. The rains were short lived so it was only

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filled to about a quarter capacity. Since it was quite new, there was not sufficient information

to be obtained on usage and useful storage per year.

Private Dams

These were usually constructed and used to the owner’s specific needs and regulations. There

were of smaller size than the public dams. There were several such dams and two were

considered; Phillip’s and John’s dams.

Phillip’s dam was used for irrigation, domestic supply and livestock. The domestic water was

pumped to tanks and treated before use. The irrigation water is also pumped into elevated

tanks and then allowed to flow by gravity to the farms.

John’s dam was used mainly for domestic supply and livestock. Occasionally it would be

used for irrigation too.

Boreholes

In the attempt to increase water resources and to provide clean drinking water, there had been

efforts to sink boreholes in the area, usually by donor-funding. There were three dug for the

public namely, Manos Unidas, Musaalani Egyptian Project and Miumbuni Secondary School.

Only one was functioning without significant problems, i.e. the Manos Unidas borehole in

Misuuni village. There was one private borehole, owned by one Patrick Mailang’a.

Water from the boreholes was mainly used for domestic purposes. Borehole water was

usually hard water therefore compromising taste and mineral content. Water samples from

each boreholes were taken for laboratory analysis. Readings from the various meters and

records available were also taken to get the yield from each borehole. Below are details about

these boreholes;

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Manos Unidas Borehole

This was a project conducted by a donor organisation from Spain, namely, Manos Unidas.

Their main objectives were to supply clean drinking water, water for domestic use and water

for irrigation. Residents who could afford piping had water pumped to their houses from the

borehole. There was a huge irrigation farm, located near the borehole, which entirely relied

on irrigation with water from the borehole. Initially, the borehole project had a planned water

distribution system via water kiosks in various parts of Misuuni but only two of such kiosks

were fully functional.

Access to the borehole’s water by some residents of this area was limited because of long

distances. This water was also obtained at a fee hence only those with the necessary funds

could have a stock enough for a full tank or for farming. The fee was Ksh. 3.00 per 20-litre

container of water. Most people using this facility would fetch just enough water for drinking,

usually 40 litres per week for one household.

The yield of this borehole is 20 cubic meters per day. There are 5 elevated tanks on site with

a storage capacity of 100 m3.

Musaalani Borehole

This was a project done in corporation with the Egyptian government, in 2002. Its sole

objective was to provide clean drinking water. The borehole had a hand pump installed on

site to help in drawing water. However, the project collapsed after a few months for unknown

reasons. No checks or repairs had been attempted to determine and remedy the cause.

Miumbuni Secondary School Borehole

This was a project also done by the Egyptian government in 2002, to supply water for use in

the school. The school had a water tank for storage. There were no borehole logs available.

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The borehole sometimes has very low yields. Attempts have been made to remedy the

problem but the main cause for the problem is yet to be identified.

Patrick’s Borehole

By the time of this study, it had just been recently drilled and it was noted that it had

comparatively higher yields. The output capacity per day is 33m3. The boreholes supplied

water to his house, to water kiosk where it’s sold to the public at Ksh. 3.00 per 20-liter

container and to his farm for irrigation. The owner had installed elevated water tanks for

storage whose capacity is 40 m3 and also to enable flow by gravity to a water kiosk and to

irrigation farms.

Rainwater Collection

During the rainy season, a few households collect rain water by the use of roof gutters for

storage in tanks. This method was exclusive to those with the means to afford a water tank

and also a corrugated sheet roof.

Usually this water was exclusively used for drinking. Water for all other domestic purposes

was drawn from other sources. In some cases where the owner had a large roof and a

sufficient storage tank, this method sustained an all year round drinking water supply. As in

the case of privately owned dams, the public is allowed restricted access to these tanks for

drinking water in rationed portions in the case of severe drought.

It was noted that roof gutters were not regularly cleaned so there was accumulation of

sediments into the tanks. Counts were made of the number of households with rainwater

collection. Readings of the volumes of storage were made and where there were not

available, measurements were done to compute volumes. Water samples were taken from

randomly selected rainwater collection tanks for further analysis in the laboratory.

17

Below are some charts depicting data on the water sources and the existing water supply

condition.

Figure 3-2 Water Source - Consumption.

Figure 3-3 Water Retrieval Difficulties.

18

Figure 3-4 Retrieval Demographics

Figure 3-5 Water Consumption - Agriculture.

19

Figure 3-6 Volume of Water Stored

3.4. Existing Demand

This was analysed by splitting the demand in to several categories. These categories were;

(i) Institutional demand – water needed at schools and hospitals

(ii) Commercial demand – water needed at commercial centres

(iii) Domestic demand – water for needed for residential use

Institutional Demand

The table below shows institutional demand as from the surveys conducted.

Name of institution Attendance per day water consumption (m3/day)

Miumbuni Sec. School 450 6.8

Primary schools 400 5

Dispensary 300 0.35

Police Station 10 0.20

TOTALS 12.35

Table 3-1 Institutional demand of water per day

20

Commercial Demand

The table below shows the demand from commercial establishments operating in the area.

Business activity Number of each Total m3/day

Hotels/restaurants 7 1.5

Slaughter houses 2 0.2

Butcheries 6 0.96

Shops/kiosks 34 2.04

Hair and beauty 9 1.08

Commercial Farms 1 2.5

TOTALS 8.28

Table 3-2 Commercial demand per day

Domestic demand

From the survey. Most homesteads have an average of 5 to 6 household members. From the

exact calculations of the households surveyed the total demand per day is 5.308 m3/day. By

extrapolation of this number to reflect the entire population, the total domestic water demand

in the area is 42.64 m3/day.

3.5. Existing Quality

To obtain date on quality there were two phases;

Administering questionnaire, conduction interviews and visual observations.

Laboratory analysis of collected water samples.

Those who were surveyed were asked to determine the quality of their water, using

a scale from 10 to 250, with 10 being the most clear and 250 being the least clear. It was

determined that the quality of the water varies between the wet and dry seasons. The average

21

water quality reported for the wet season was 50 per the test comparison samples and the

average water quality reported for the dry season was 125. Furthermore, 55% of the

homesteads surveyed reported described the water as “sour” and 35% described the water as

“dusty/muddle,” along with other negative descriptions. During the dry season, the water

contained more particles and the water was not as transparent, in comparison to the wet

season when fewer particles and clearer water was observed. Although 95% of the

homesteads reported particles present in their drinking water, only 45% of the homesteads

consistently filter their water and 10% of the homesteads rarely treat their water. The most

common filtration methods were straining through a cloth and using the chemical ‘Water

Guard’. However, many homesteads chose not to use ‘Water Guard’ because it was either too

expensive or because they had been misinformed that ‘Water Guard’ caused birth defects.

Below are charts of data obtained from the initial survey with questionnaires.

Figure 3-7 Reported Waterborne Illness.

22

Figure 3-8 Particles Present in Water

Figure 3-9 Percentage of Homesteads That Treat Their Water

23

Figure 3-10 Drinking Water Descriptions

Figure 3-11 Filtration Methods Used for Water Treatment

Figure 3-12 Water Quality Reference.

24

For laboratory tests, samples of 7 water sources were considered. These were; Kathaana

River, Misuuni Dam, Kathuku Dam, Manos Unidas Borehole, Miumbuni Secondary School

borehole, Rain Water and Phillip Ndolo’s home-treated water. These samples were then

analysed for the following parameters; turbidity, pH, colour, fluoride ion content, chloride ion

content, hardness, total solids, suspended solids. Four sources were considered for coliform

test which were; Kathaana River, Misuuni Dam, Kathuku Dam and Manos Unidas Borehole.

Since it was not possible to E. Coli tests in the University of Nairobi, test data conducted by

an independent team in August 2014 were considered. Other test data was also obtained from

the results send by this team. The procedure followed for each testing method is found in the

appendix. Below are tables, showing the results obtained from laboratory analysis for each

sample;

Parameter Units Results WHO standard KEBS standard

Fluoride ion mg F/L 0.266 Max 1.5 Max 1.5

Turbidity FTU 4.4 Max 5 Max 5

Total hardness mg CaCO3/L 152 Max 500 Max 300

pH 1-14 scale 7.70 6.5 – 8.5 6.5 – 8.5

Colour Hazen 10 Max 15 Max 15

Chloride ion mg Cl/L 44 Max 250 Max 250

Suspended Solids mg/L 120 Max 1000

Total solids mg/L 3.4 Max 30 Max 30

Coliform MPN/100ml 39 - -

Table 3-3 Laboratory results for Kathaana River water sample

25

Parameter Units Results WHO standards KEBS standard


Turbidity FTU 330 Max 5 Max 5


pH 1-14 scale 7.36 6.5 – 8.5 6.5 – 8.5




Suspended Solids mg/L 240 Max 1000 240


Table 3-4 Laboratory results for Kathuku Dam water sample



Turbidity FTU 310 Max 5 Max 5


pH 1-14 scale 7.29 6.5 – 8.5 6.5 – 8.5



Suspended Solids mg/L 1250 Max 1000 -



Table 3-5 Laboratory results for Misuuni Dam water sample

26





pH 1-14 scale 7.55 6.5 – 8.5 6.5 – 8.5




Coliform MPN/100ml - -

Table 3-6 Laboratory results for Miumbuni Secondary School Borehole water sample





pH 1-14 scale 7.78 6.5 – 8.5 6.5 – 8.5



Suspended Solids mg/L 160 Max 1000 Max 1000



Table 3-7 Laboratory results for Phillip Ndolo Treated Water sample

27





pH 1-14 scale 8 6.5 – 8.5 6.5 – 8.5





Table 3-8 Laboratory results for Lazarus’ homestead rain water sample





pH 1-14 scale 7.56 6.5 – 8.5 6.5 – 8.5




Coliform MPN/100ml Nil - -

Table 3-9 Laboratory results for Manos Unidas Borehole water sample

The results above have been compared with standards to check for conformity. From that

comparison it is clear that the sources that can provide safe domestic and drinking water are

rain water collection, the boreholes and the treated dam water. The untreated dam water and

river water are unsafe for drinking and domestic use.

28

4. ANALYSIS

4.1. Water Demand Projections

The method adopted for preparing the water demand projections has been to analyse water

consumption for each category separately and provide forecast for 2016, 2020 and 2025

which are respectively the immediate, immediate future and future design horizons.

Domestic Consumption Projection

Domestic consumers constitute the largest category of consumers. The consumption per

person in litres per day has been projected and combined with the population projections in

order to derive the total domestic water demand. The population is projected to grow at 4%

per annum for the next four years and then at 6% per annum for the next ten years.

Also taken into account is the proximity to water source, the income level, the price of water

and the quality of supplied water. The tables showing both the population projections and

domestic water demand projections are shown below;

Year Population

Present (2014) 2000

2016 2117

2020 2638

2025 3561

Table 4-1 Population projections

29

Year Water demand (m3/day)

Present (2014) 42.64

2016 47.12

2020 61.11

2025 82.49

Table 4-2 Domestic water demand projections

Commercial Demand Projections

Commercial water demand is expected to rise at a rate at east equivalent to the growth in

population and in line with the performance of the area’s economy. A growth rate of 5% is

assumed.

Year Commercial demand (m3/day)

Present (2014) 8.28

2016 8.96

2020 10.95

2025 14.06

Table 4-3 Commercial water demand projections

Institutional Demand Projections

The institutional water demand is dealt with on a more general basis. It is assumed that this

demand grows in sync with population growth and also in line with economic growth. The

assumed growth is 5%.

30

Year Institutional demand (m3/day)

Present (2014) 12.35

2016 13.38

2020 15.71

2025 20.15

Table 4-4 Commercial water demand projections

Demand vs Supply Deficit

Below is a table showing the totals from water demand projections.

Category Demand in m3/day

2014 2016 2020 2025

Domestic demand 42.64 47.12 61.11 82.49

Commercial demand 8.28 8.96 10.95 14.06

Institutional demand 12.35 13.37 15.71 20.15

TOTALS 63.27 69.45 87.77 116.7

YEARLY TOTALS in m3/year 23,093.55 25,349.25 32,036.05 42,595.5

Table 4-5 Summary of Water Demand Projections

The only available water sources at the moment whose capacity can be gauged is rainwater

collection and borehole water. The other sources are not viable for current supply unless they

are treated so they were not analysed as supply volumes. Only about 4% of the population

had means to afford and had installed rain water collection systems on their roofs with

enough storage for year round supply of drinking water. The supply was however not enough

31

for any other purpose besides drinking. Dam water and river water were unsafe for drinking

without treatment, but were a considerable supply of water.

The maximum capacity of Kathuku dam was an average of 32,572 m3 per year. However, it

was usually at 1/3 capacity which is 10,857 m3. Misuuni dam had a capacity of 10,908 m3 but

was also usually at 1/3 capacity throughout the year, which was 3,636 m3 per year. For both

dams, once the rainy season was over, the water quality would deteriorate such that only half

of the aforementioned quantity was useful storage. Hence combine, the capacity from dams is

7, 246.5 m3 per year. This figure also considered sedimentation.

The Manos Unidas borehole has a daily yield of up to 20 m3/day which amounts up to 7,300

m3 per year. The yield of the Miumbuni Secondary School borehole is estimated to be about 3

m3 per day. This amounts to about 1090 m3 per year. In total therefore, the publicly used

supply systems yield a supply of 15,636.5 m3 per year which falls short of the current demand

of 23,093.55m3 per year. Only the borehole water out of the publicly available supplies is

safe for drinking. This leaves a further deficit of 14,703.55m3 per year.

The above date is represented on the table below

Source Capacity (m3/year) Safe Supply Capacity (m3/year)

Kathuku Dam 10,857 -

Misuuni Dam 3.636 -

Manos Unidas Borehole 7300 7300

Miumbuni Secondary School

Borehole

1090 1090

TOTAL 15636.5 8390

Demand – Supply Deficit 7,457.05 14,703.55

Table 4-6 Summary of demand and supply deficit

32

As per the above computations, the selected measures must be able to meet the needs as

indicated above. The options shall thus be evaluated in terms of ability to meet this deficit.

Since there is already a current deficit, then it must be met as soon as possible hence the

option should be viable immediately.

4.2. Overview of Options

The options were chosen with regard to viability and also acceptability by the community.

There were three options considered:

(i) Borehole drilling

(ii) Rehabilitation of existing water resources

(iii) Rainwater collection as supplement

Borehole Drilling

This was the community’s preference. It was mainly chosen based on their knowledge. The

common perception in the area is that borehole is safer for drinking and is guaranteed

throughout the year. This option involved drilling a borehole at a specific site centrally

placed within the area. A plot of land had already been identified and a hydrographic survey

was already done by the landowner.

The suggestion was to drill a borehole here with the necessary pumping station. Water is to

be pumped to storage tanks elevated above the ground. From there, it would flow by gravity

to water “kiosks” in six different points in the areas. The water points were fairly distributed

to serve residents, commercial centres and public institutions. Pumping would be required to

some areas where the slope doesn’t allow flow by gravity. [Pipes laid to these sources by the

33

community]. There was no treatment suggested for the groundwater, in the initial plans.

This was partly because the locals assumed groundwater was safe for drinking.

A map of the intended supply system is shown in the appendix.

Utilization of Existing Water Resources

This option was based on the argument that the existing sources, if well managed and

coordinated, could have been sufficient to meet the need. This would involve several

undertakings for different sources to improve quality and increase uptake.

For clearer analysis, the various possible measures were analysed in two categories;

(i) Ground water options

(ii) Surface water options

The suggested options are discussed briefly below;

(i) Groundwater Options

There were three existing boreholes in the area that could have either been optimized in use

or repaired to increase the water supply. The various options are discussed below;

a. Optimization of Manos-Unidas Borehole

The Misuuni Manos-Unidas borehole was not being used to maximum capacity. It could still

be utilized to supply water to current users. It could serve the Misuuni Market by the

construction of a water kiosk there. There would be no need for storage in this case, just

construction of water kiosks. Flow would happen by gravity from the on-site tanks.

It was also noted that it would improve supply to repair broken pipes to two existing water

kiosks that weren’t functional and to install meters in all the water points to facilitate

measurement of the water (for payment). Revenue from sales would be used for O&M.

34

b. Incorporation of Patrick’s Borehole

Patrick Mailang’a was willing, at a fee, to be incorporated into the public water supply

system by using his borehole to supply the surrounding area with water. There already was a

water kiosk outside his home with sufficient storage and a meter. Water was being sold at

Ksh. 3 per 20 litre container.

The idea involved setting up two other water kiosks; one near the Miumbuni Preparatory

School and another at the Ngiti water point as shown in the appendix map. Every kiosk

would have a meter and a storage tank. Sales from the water kiosk would go directly to

Patrick Mailang’a. Maintenance would also be from the funds collected through such fee.

Surface Waters

Dams and rivers are the main sources of surface water in this area. If rehabilitated, improved

and their use controlled, water yields could increase. Several options were considered here:

a. Differential use/Restricted Access

To monitor and regulate use, it was suggested to fence the dam boundaries. This would

prevent people from dirtying the water by wasting which the boundaries and also monitors

water use. For the various dams, proper regulations on use would set. For instance, pumping

water for irrigation would be billed to help in maintenance or also, putting a cap on the

maximum amount of water pumped must be set. Also, at Kwa Kathuku Dam, livestock could

be denied direct access. Instead, water could be pumped to a watering point for livestock.

This would alleviate water contamination by faecal matter.

35

b. Filtration of Dam Water

For abstraction from site and use in the surrounding areas, water from the dams could be

treated. Since dams are the main source of water for domestic use this could provide a safe

supply. For this system, four tanks could be set up. One for sedimentation to reduce turbidity

and settle-able solids, two for slow sand filtration to disinfect the water and then one elevated

tank for storage to allow flow by gravity. Two pumping stations would be needed; one for

pumping water from the dam to the sedimentation tank and another for pumping water up to

the storage tank.

At Misuuni dam, this could supply three water points, one at Musaalani market and another

at a settlement near the proposed boreholes site and one on site.

For Miumbuni market and the surrounding residential areas, a similar water system would be

set up with water being drawn from Kathuku dam. Three water points would be set up too;

one at Miumbuni market, one at a settlement near the dam and one onsite at Kathuku dam.

c. Rivers

These shall be left to livestock and irrigation of nearby farms. For livestock there shall be no

control. For irrigation, in order not to deplete the water resources available for livestock;

there shall be set up controls as per riparian rights.

Rainwater Collection as Supplement

From reconnaissance studies, it was observed that rainwater collection is a viable option.

This was suggested especially for institutions with high demand water demand. It was an

option with one time investment and supplied considerable quantity. It was considered to

have rainwater collection from roots of following institutions:

Secondary School

36

Primary Schools

Police Post

Dispensary

The collected water supplied would last for a considered amount of time in a year, in most

cases, more than 6 months. It would require fixing water gutters on roofs, buying storage

tanks, doing some treatment in case of compromised quality and periodic maintenance. No

billing is required. This would supplement water from other sources.

4.3. Evaluation of Alternatives

This delved deeper into the suggested options and analysed them according to the

measurements of success. Key features of each possible options were further broken down

specifics and analysed.

Before getting into each option, one by one, it must be noted that the legalities concerned

with each of them are quite similar. So below is an overview of legal feasibility issues.

Legal feasibility

According the water act of 2002, every water resource is vested in the State, subject to any

rights of user granted by or under the act or any other written law. The right to the use of

water from any water resource is vested in the Cabinet Secretary in charge of the Ministry of

Water, except to the extent that it is alienated by or under the act or any other written law.

The act also creates WRMA which is in charge of the following as pertain this particular

project;

i. to develop principles, guidelines and procedures for the allocation of water

resources;

ii. to receive and determine applications for permits for water use

37

iii. to monitor and enforce conditions attached to permits for water use;

iv. to regulate and protect water resources quality from adverse impacts;

v. in accordance with guidelines in the national water resources management

strategy, to determine charges to be imposed for the use of water from any water

resource;

vi. to gather and maintain information on water resources and from time to time

publish forecasts, projections and information on water resources;

vii. to liaise with other bodies for the better regulation and management of water

resources;

It is therefore key to ensure that the process as required by WRMA is followed for each of the

steps. Each option will be analysed as per the ability to meet these requirements and also

checked whether there are measure already taken to ensure the conditions are met.

The permit application process is as follows;

38

Figure 4-1 WRMA water permit application process

Also, as per the act, a "community project" means a project approved by the Authority and

operating under a permit for one or more purposes which are;

(a) connected with the use of water or the drainage of land situate entirely, or for the most

part, within a given area; and

(b) classified by the Authority, with the approval of the Minister, as community purposes;

which has been declared by the Authority, by notice published in the Gazette, to be a

community project for the purposes of this Act

This project thus as per the above sufficiently meets the requirements to be classified as a

community project.

39

Option 1; Drilling a New Borehole

Legal feasibility – first of all a water searching permit is applied for, which has already been

done. After that, a hydrological survey is done. This has already been done. The results are

compiled in a report after which a drilling permit is applied for in the regional WRMA office.

This has already been done. The land rights and the water rights required have been hence,

required and every legal step followed. Only the drilling is yet to be done at this point. All the

relevant certifications and approvals are attached in the appendix.

Water quality feasibility – According to the results in the analysis section of this report, all

boreholes within this area have a safe supply of water for domestic use. It is expected

therefore that the water will be of good quality. The only concern is the hardness which could

affect the pumping machinery and pipe system.

Water quantity feasibility – The two boreholes closes to the borehole proposed site have a

yield of 33 m3 and 20 m3 per day. The yield is expected to be within the range of 28 to 47 m3

per day. The deficit required for the current demand is about 40.5 m3 per day. This means that

this borehole has the probability of between 75 – 95% of meeting the deficit.

Economic feasibility – the major concern for this option is the amount of money required an

s one time investment. The quotations indicated in the appendix indicate a sum of about 1.5

million shillings as the initial capital for drilling the borehole. The purchase of water tanks,

their erection, and construction of water kiosks with laying of pipes for water supply

altogether will cost another 1.75 million bringing the cost of the project to 2.75 million. Most

of the manual labour as agreed by the community group will be voluntary. This initial amount

makes it very expensive. It is the most expensive of all the options. Especially in terms of

first time investment. The water would be supplied at a rate and based on studies and using

the Manos Unidas borehole project as a reference, there is a chance of making enough money

40

for maintenance of the project. Water is usually sold at 3 shillings per 20 litres. For farms and

other bulk supply demanded, the rate is 40 cents per litre. A meter is installed on all water

kiosks and on site to measure all water that is sold and to keep a log against the monies

collected. A record by the community group showing previous sales from their first borehole

project is attached in the appendix. It is projected that the average daily collection will be

2,000 to 3,000, which amounts to a maximum of 1 million shillings per year and a minimum

of 700, 000 shillings. This money will be used to pay for the maintenance which includes;

staff, generator fuel, pump maintenance, water supply system repairs. These shall be logged

and since the community project is externally audited, there shall be accountability in the

financial handling of all payments.

Operational Feasibility – for the operation of this project, a good design and a systems

approach is crucial. The design proposed is pumping water to elevated tanks and then

allowing flow by gravity to other parts of the area. This is feasible because the area is higher

than most of the area. The additional elevation due to the elevated tanks makes it possible to

supply some points which are a bit higher than the borehole location. Labour is also required

on site for pumping, running of recurrent sales, maintenance and security. Since all the labour

besides professional labour such repair of pumps. For recurrent technical jobs such as fuelling

of generator and operation of pumps, the staff shall be trained. Operation for this particular

option is therefore feasible.

41

Option 2; Rehabilitation of Existing Resources

Legal Feasibility – for the ground water options, permits will be required for the expansion

of works. Since there are already permits for the existing boreholes systems, the legal

requirements would land easement documents for the pipes to be laid and the kiosks to be

constructed and also approval of works by the county council of Machakos. This is subject to

the submissions of the engineering and architectural designs of work. It will also be required

to have a written agreement with Mr Patrick Mailanga concerning the incorporation into the

public system.

For surface water options, it shall be required to acquire land easement for construction of the

facilities suggested, water permit for abstraction of water from the dams for treatment and

distribution and approval of all construction works by the county council authorities.

The suggestion to set community rules for the separated uses of water would require public

sensitization. It would be difficult to set up written laws as this would involve engaging

WRMA and there would be several legal fees required so instead, there should be mutual

agreement within the community for differential water use. This would help in preventing

contamination of dam, water by livestock.

Operational Feasibility - For the groundwater options the operational and maintenance

works will be as before. Since it’s only an expansion of works, no extra training is required.

Only labour for sale of water at the new water points will be required. The major concern is

the maintenance of pipe and repairs to be conducted and by hiring a professional plumber this

can be easily done.

For the surface water plan, initial training of the staff operating the filtration plant is

necessary after which they can train others. Slow Sand filters have a very high self hep

compatibility hence the locals can be trained to run it. Since the CBO would oversee the

42

implementation of the project, it would provide the initial labour force required. There O&M

practices for SSF required are mainly for cleaning the filter and this can easily be done since

the system provides for two filters. Hence as one operates, the other can be cleaned. Material

for the plant shall be locally sourced and provided by the community for free so maintenance

and replacement should not pose a problem. The pumps for the system require fuel and

periodic maintenance. The funds for these shall come from the sales of water from this

treatment plant. Operational costs are incurred almost solely from the cleaning of the filter

beds. No chemicals or other materials are needed for the process. No compressed air,

mechanical stirring, or high-pressure water is needed for backwashing. There is thus a saving

not only in the provision of plant but also in the cost of fuel or electricity

Water Quantity Feasibility – The groundwater option for expansion works at Manos Unidas

and repair of the pipes/water kiosks would only improve the distribution system. It would not

add any more water into the existing system but rather eases access to it. It would be expected

that the water point at Misuuni market would cater for all commercial needs at the market

amounting up to 1.53 m3/day. However, the incorporation of Patrick’s borehole into the

system would plug in only half of his yield, amounting to 16.5 m3 per day or 6022.5 m3 per

year.

For the surface water plans, the only supply added will be safe supply of domestic water.

Since water from the dam will also be used for other purposes only ½ the water in Misuuni

dam will be treated by filtration annually. As for Kathuku dam, the fraction of water treated

will be 1/3 because livestock supply is required, besides the other uses. Initially the water

would have been unsafe for domestic use but after treatment, the supply would be as follows;

Kathuku Dam – 3619 m3 per year

Misuuni Dam – 1818 m3 per year

43

The summation of both the groundwater and surface water options would provide a total

supply of 11, 459.50 m3 per year of safe domestic water. It would meet 78% of the demand

for needed safe supply of water.

Water Quality Feasibility – the groundwater plans are okay in terms of water quality. The

existing boreholes have been tested for water quality and all standards are meant.

The surface water option incorporates slow sand filtration to disinfect the water. Slow sand

filtration is an extremely efficient method for removing microbial contamination and will

usually have no indicator bacteria present at the outlet. If the effluent turbidity is below 1.0

nephelometric turbidity units (NTU), a 90 to 99% reduction in bacteria and viruses is

achieved (NDWC 2000). To reduce turbidity to such levels, a sedimentation tank has been

provided and also a basic filter will be put in the pipes linking the sedimentation tank to the

SSF so as to reduce turbidity. Slow sand filtration is generally not effective for the majority

of chemicals. However, it can be argued that chemical standards for drinking water are of

secondary concern in water supply subject to severe bacterial contamination (WHO 1996). A

summary of the effectiveness of SSFs is shown in the table below;

Highly effective for Somewhat effective for Not effective for

- Bacteria

- Protozoa

- Viruses

- Turbidity

- Heavy metals (Zn, Cu, Cd, Pb)

- Odour, Taste

- Iron, Manganese

- Organic Matter

- Arsenic

- Salts

- Fluoride

- Trihalomethane (THM) Precursors

- Majority of chemicals

Table 4-7 Typical treatment performance of slow sand filters.

http://www.sswm.info/glossary/2/letterf#term3351

http://www.sswm.info/glossary/2/letteri#term1444

http://www.sswm.info/glossary/2/letterb#term38

http://www.sswm.info/glossary/2/lettere#term143

http://www.sswm.info/glossary/2/lettert#term2687

http://www.sswm.info/glossary/2/lettern#term376




http://www.sswm.info/glossary/2/letterd#term1069

http://www.sswm.info/glossary/2/letterw#term1336


http://www.sswm.info/glossary/2/letterp#term421


http://www.sswm.info/glossary/2/letterh#term115

http://www.sswm.info/glossary/2/letterc#term2372

http://www.sswm.info/glossary/2/lettero#term2693



http://www.sswm.info/glossary/2/letters#term2406

44

The water in the dams has no trace of chemicals found that would need disinfection therefore

this option is feasible for provision of safe water for domestic use.

Economic Feasibility – For the groundwater options, it would be one time investments in

lying of pipes and construction of water kiosks. The breakdown of costs is as follows;

Item Cost (Ksh)

Manos Unidas Construction of one water kiosk + fitting of meter +

installation of tap

Purchase and Laying of pipes to water kiosk

Repair of water pipes + installation of meters at 2 water

kiosks

45, 000

56,000

23,500

Incorporation

of Patrick’s

Legal fees for agreements

Construction of two water kiosks + fitting of meter +

installation of tap

Purchase and Laying of pipes to water kiosk

5,000

90,000

147,000

TOTALS 366,500

Table 4-8 Breakdown of cost for ground water options

It is projected that this will have a direct uptake with sales per day as follows;

Water point Sales per year (Ksh.)

Misuuni market 56,395

Manos Unidas water points 182,500

Patrick’s water points 547,500

TOTALS 786,395

Table 4-9 Revenue from water sales

The collected revenue will be enough for fuelling and maintenance operations throughout the

year. Therefore the groundwater option will be self-sustainable after implementation.

45

As for the surface water option, the costs will be mainly for construction works, pumps

required and the pipes. Land will be provided by the community as well as labour and the

locally available materials such as sand and gravel. There will be a cost for initial training of

personnel who will be running the plant. The breakdown of costs for the treatment plant and

related works is generally as follows;

Location Item Cost (Ksh.)

Misuuni Dam Construction of SSFs and RC sedimentation

tank

Piping and pumping system on site

Elevated storage tank + supporting structure

Construction of three water kiosks + laying

of pipes + installation of meter

325,000

37,000

128,000

105,000

Kathuku Dam Construction of SSFs and RC sedimentation

tank

Piping and pumping system on site

Elevated storage tank + supporting structure

Construction of three water kiosks + laying

of pipes + installation of meter

325,000

37,000

128,000

145,000

TOTALS 1,230,000

Table 4-10 Breakdown of costs for filtration plants

It is projected that there will be a 90% uptake at the markets and a 75% uptake in the

settlements hence the sales of water will collect revenue as follows;

46

Source Revenue per Year (Ksh.)

Misuuni Dam 204,525

Kathuku Dam 447,851

TOTALS 652,376

Table 4-11 Revenue from sale of treated water

It is projected that the cost of pumping water the basic O&M cost (fuel + staff) will be

sufficiently covered by the revenue collected hence the treatment option will be self-

sustaining.

The total cost of rehabilitation of existing sources is Ksh. 1,596,500 and all the suggested

plans are one time investments which are self-sustainable.

Option 3; Rain Water Collection as Supplement

Legal Feasibility – There are no legal requirements for trapping rain water using roof

catchment system. Therefore, this option is legally feasible.

Operational Feasibility – This system would be easy to operate since all water would be

directed to tanks and fetched from there. There would be no pumping required and

maintenance would be minimal. The only maintenance to be done would be the cleaning of

roofs every now and then and repair of gutters.

Water Quality Feasibility – From the water tests done on the sampled roof-collected rain

water within the area, the water would be safe for drinking and all other domestic uses. No

extra treatment would be required. To improve quality it is advisable to install a water filter at

the entry point of water into tanks from roof gutters. This would trap sediments from roofs.

Also, it would be further improve quality to clean the roofs periodically.

47

Water Quantity Feasibility – The water collected from a roof catchment system is

dependent on the area of the roof and the intensity of rainfall in the area. The formula used in

calculations is;

Q = KIA where;

K is a coefficient, I is rainfall intensity and A is area of catchment roof

The area of all roofs at the institutions that would be used for roof catchment were measured

and the total flow calculated and the results tabulated below and then compared with demand

for each of the institutions. All the primary schools have been summed up together as in the

analysis for demand because the design is similar for all, having 8 classrooms, a detached

kindergarten block and a detached staff office block.

Institution Roof Area

(m2)

Quantity

(m3/year)

Demand

(m3/year)

Deficit

(m3/year)

%

Mitigated

Dispensary 108 86.4 127.75 41.35 68%

Miumbuni Sec. 740 592 1870 1278 32%

Primary Schools 1560 1248 1350 102 92%

Police Station 68 54.4 73 18.6 75%

Table 4-12 Quantity supplied by roof catchment vs demand

For the above, it is plain that although it is not enough to meet all the demand it mitigates the

demand to some percentage above 50% except for Miumbuni Secondary School. In the case

of Miumbuni secondary school, the borehole providing safe drinking water of 1090 m3 per

year hence the deficit mitigated increases to 73% from the projected 32%.

As an initial measure then this option is viable for now and will also provide to future needs.

However, this option does not help with domestic demand or commercial demand.

48

Economic Feasibility – The cost for this option is a one-time investment. The O&M costs

are negligible and would only be for cleaning of roofs and gutters. The initial cost involves

setting up concrete bases for all tanks, installation of roof gutters, purchase of litre tanks for

storage, installation of taps and filters. The total cost breakdown is as indicated below;

Institution Item Cost (Ksh.)

i. Sec. school

ii. Primary schools

iii. Police Station

iv. Dispensary

Reinforced concrete bases for tanks,

4x4

129,600

129,600

129,600

129,600

i. Sec. school

ii. Primary schools

iii. Police Station

iv. Dispensary

Purchase of tank of capacity

- 15, 000 litres

- 12,000 litres

- 8,000 litres

- 10, 000 litres

186,000

143,000

78,000

104,700

i. Secondary

school

ii. Primary schools

iii. Police Station

iv. Dispensary

Purchase of gutters for roofs

- 120 m

- 260 m

- 14 m

- 20 m

10, 200

22,100

1,190

1,700

i. Sec. school

ii. Primary schools

iii. Police Station

iv. Dispensary

Installation of gutters, taps and placing

tanks

4,000

10,000

2,000

2,000

TOTALS 1,083,290

Table 4-13 Cost estimations for Rain water harvesting

49

As a mitigation effort for institutional water demand, the one-time cost of this option would

be Ksh. 1,083,290.

The current deficit is met by purchasing water at Ksh. 3 per 20 litres delivered from nearby

dams which not even safe for drinking. The primary schools cannot afford to pay for water so

the students have to fetch themselves from nearby dams hence precious time is lost walking

long distances. The total cost for buying water by the institutions is thus Ksh. 603,987.50.

The breakdown for the cost mitigation per institution is as shown below. The calculation have

considered that the rain water collection only meets needs up to a certain percentage;

Institution Cost of Rain

Collection System

Current Cost of

Water per Year

(Ksh.)

Cost with Rain

Water Collection

per Year (Ksh.)

Miumbuni Sec. School 329,800 117,000 31,590

Dispensary 238,000 19,162.50 1,533

Police Station 209,600 10,950 2,738

Table 4-14 Comparative costs after Rain water system

For the above three institutions, there’s economic gain because this one time investment

saves a greater amount of money and is therefore advisable.

50

5. CONCLUSION AND RECOMMENDATIONS

5.1. Conclusion

In accordance with the set objectives for this project and the discussion found ion the analysis

chapter above, the following conclusions can be drawn from this investigation.

1. The water needs of the community were determined primarily based on accessibility

to a water source and the general availability of clean water. The Misuuni community

requires non-available clean water for domestic uses such as but not limited to

drinking, cleaning, sanitation, and personal farm use. Currently, only the boreholes

and personal home rain-water catchment systems have a good supply of safe domestic

water. With the lack of clean water individuals from the community are susceptible to

waterborne disease and are prone to miss days of work and school.

2. The present total water demand vs the water supplied are as follows;

Capacity (m3/year) Safe Supply Capacity (m3/year)

Supply 15636.5 8390

Demand 23093.55 23093.55

Demand – Supply Deficit 7,457.05 14,703.55

Table 5-1 Demand vs Supply Conclusion

The current water resources are not enough in quantity and are lacking, even more in

Quality and are therefore there’s a need for new water supply system. This new water

system must be able to meet the current need either fully or to a suitable percentage.

3. The availability of clean water will substantially improve the quality of life for the

overall Misuuni community. Further the availability of clean water will allow for

51

increased productivity in the agricultural sector, both in terms of crops grown and

available human capital.

5.2. Recommendations

In the selection of the most viable alternative source of water for the Misuuni community,

several factors were taken into account. These were;

i. Capacity of the works

ii. Time of implementation

iii. Cost of implementation

iv. Operational and maintenance requirements

Capacity of Works

(i) The borehole option has a capacity of an estimated 28 m3 to 47 m3 per day. Given the

50% success rate of the borehole yield predictions in the area, this is not enough to

meet the current demand but it mitigates it by about 59% hence it would require to be

implemented in conjunction with another option. It is not a sure option and true data

can only be determined from actual drilling.

(ii) The rehabilitation of existing water resources would yield an estimate of 32 m3 per

day. This would leave a deficit of 5.1 m3 currently and but would not be able to cope

with future demand.

(iii) The rain water collection option would mitigate the water shortage in institutions by

83% percent if current rainfall statistics remain the same. It would provide the

institutions with a combined supply of 1980.80 m3 compared to a unmet demand of

2306.25 m3 per year

Time of Implementation

52

(i) The borehole option would take between six months and a year to implement. This

would include drilling and construction of all relevant works. Taking 2015 to be the

year of implementation, this project can be commissioned to meet this target

(ii) The rehabilitation of the existing supplies would be in phases and could take between

one year and one and a half years to implement mainly because of the technical, legal

and operational issues that must be coordinated. 2017 is the realistic date of possible

completion.

(iii) Rain water collection at the public institutions could be implemented by the end of

2015.

Operation and Maintenance Requirements

(i) The borehole option will be gravity flow so most O&M costs will be for the generator

on borehole site and for pipes.

(ii) The major cost in the rehabilitation of existing sources would be operations of water

treatment as well as generator and pump maintenance cost.

(iii) The only O&M cost in the rain water harvesting case would be cleaning of rooftops

and repair of roof gutters which is very cheap.

Cost of Implementation

(i) The cost of implementation for the borehole would be Ksh. 3,523,459. It is a one-time

initial investment which O&M costs catered for by sales from water kiosks.

(ii) The cost of the rehabilitation of existing sources would be Ksh. 1,596,500. The O&M

costs would be catered for by sales of water at the water kiosks.

(iii) The cost of mitigation by rain water harvesting would be Ksh. 1,083,290. The O&M

costs are negligible.

53

Selected Alternative

The immediate mitigation of the water scarcity by rain water harvesting in institutions was

chosen as the first measure based on its economy and also the ability to mitigate the

institutional demand beyond 50% in each case.

For a follow up project, the rehabilitation of existing water sources was chosen as the viable

option because of the ease in implementation, economy and ability to meet a greater

percentage of the current demand than the borehole option. The borehole option would

require further field studies to check for suitability of other sites and also, there’s a chance

that it could be fully operational to the projected output. The filtration of dam water by use of

SSFs guarantees clean water without a high initial cost. Slow sand filtration systems are

characterised by a high reliability and rather low lifecycle costs. It is recommended to

implement it in phases. First at Misuuni Dam then afterwards in Kathuku Dam.

54

6. REFERENCES

Government Press (2002). Act No. 8 of 2002 - Water Act

Government Press (2006). The Environmental Management and Co-Ordination (Water

Quality) Regulations, 2006

Dezuane, J. (1997). Handbook of Drinking Water Quality, 2nd Edition, Published by John

Wiley and Sons. Edmunds,

American Water Works Association (1990). Water Quality and Treatment: A Handbook

of Community Water Supplies – 4th Edition, McGraw Hill, Inc.

Environmental Protection Agency. (1999). Water Quality Sampling Manual, 3rd Edition,

Published by EPA.

Gray, N. F. (2008). Drinking Water Quality: Problems and Solutions, 2nd Edition,

Published by Cambridge University Press.

Hem, J.D. (1967). Study and Interpretation of the Chemical Characteristics of Natural

Waters, Published by United States Government Printing Office, Washington.

Kenya Bureau of Standards. (2007). Kenya Standard: KS 459 – 1:2007, Part 1.

Letterman, R.D. (1999). A Handbook of Community Water Supplies, 5th Edition,

Published by McGraw Hill.

Linsley, R.K and Franzini, J. B (1979). Water Resources Engineering, 3rd Edition,

Published by McGraw Hill, Inc, New York.

Leonard, L Ciaccio, (1973). The 2009 Population and Housing census: Counting Our

People for Development, Volume 1, Published by the Central Bureau of statistics.

55

Ministry of Water and Irrigation. (2005). Practise Manual for Water Supply Services in

Kenya, Part A, Published by the Government Press.

National Research Council. (2006b). The Examination of Waters and Water Supplies, 7th

Edition, Published by J. and A. Churchill Ltd.

UNESCO and WHO. (1996). Water Guideline for Drinking Water Quality, Volume 1,

Published by WHO.

Huisman L. and Wood, W.E. (1974), Slow Sand Filtration, Published by WHO

BRIKKE, F.; BREDERO, M. (2003): Linking Technology Choice with Operation and

Maintenance in the context of community water supply and sanitation. A reference

Document for Planners and Project Staff. Geneva: World Health Organization and IRC

Water and Sanitation Centre.

Internet sources

i. http://ga.water.usgs.gov/edu/waterquality.html

ii. http://www.nema.go.ke/

iii. http://www.epa.gov/safewater/contaminants/index.html

iv. http://www.wrma.or.ke/

v. http://www.mit.edu/course/21/21.guide/reports.htm

vi. http://en.wikipedia.org/wiki/Feasibility_study

vii. http://www.machakosgovernment.com

viii. http://en.wikibooks.org/wiki/Professional_and_Technical_Writing/Feasibility

ix. http://oasisdesign.net/water/treatment/slowsandfilter.htm

http://www.sswm.info/library/619



http://ga.water.usgs.gov/edu/waterquality.html

http://www.nema.go.ke/

http://www.epa.gov/safewater/contaminants/index.html

http://www.wrma.or.ke/

http://www.mit.edu/course/21/21.guide/reports.htm

http://en.wikipedia.org/wiki/Feasibility_study

http://www.machakosgovernment.com/

http://en.wikibooks.org/wiki/Professional_and_Technical_Writing/Feasibility

http://oasisdesign.net/water/treatment/slowsandfilter.htm

56

APPENDIX A: LABORATORY TESTS

Field water samples obtained and tested in the laboratory. The following tests were carried

out.

a) PH

Apparatus and reagents

i. pH Meter.

ii. Beaker

Procedure

Approximately 75ml of the sample was placed in 100ml beaker. Carefully, the electrodes of

the pH meter were raised out of the beaker they are kept in and rinsed with distilled water.

Drops of water were wiped from electrodes. The electrodes were then immersed in the beaker

containing the sample. The selection was then switched to pH. The pH was read directly from

the meter. The selector switch was then turned to “CHECK”. The electrodes were then raised

carefully, rinsed with distilled water and replaced in the beaker of distilled water.

b) Chloride ion concentration


i. Potassium chromate solution.

ii. Silver Nitrate solution (0.0141N)

iii. Conical flask

iv. Pipette

v. Burette

57

Procedure

100ml of sample water was poured into the conical flask. 1ml of Potassium Chromate

solution was added. This was titrated with standard silver nitrate solution with constant

stirring until a slight red precipitate appeared. The guideline value set for aesthetic quality of

water is 250mg/L of chloride. Therefore the sample of water is below the guideline value.

c) Colour


i. Nessler cylinder.

ii. Lovibond nessleriser.

iii. Standard Hazen disc No. N5A.

Procedure

The Nessler cylinder was filled with water. It was then transferred to the right hand

compartment of a Lovibond nessleriser and used in conjunction with a white light cabinet.

The colour was then matched against the Standard Hazen disc No. N5A.The reading was then

obtained directly in degrees haven. The guideline value set for aesthetic quality of water is

15TCU (True Colour Units).

d) Turbidity


i. Turbimeter (Model 2100A).

ii. Pipette.

58

Principle of a Turbimeter

The Turbimeter 2100A operates on the principle that light passing through a substance is

scattered by particulate matter that is suspended. A strong light is passed upward through a

cell containing a sample under test during which the beam, proportional to turbidity present,

it is scattered at 90 ̊ and received by photo-multiplier tube. The light energy is then converted

to an electrical signal which is measured by the instrument. The Turbimeter is fitted with 4

sample cells; when measuring turbidities on 0 -1000 FTU a cell riser is inserted into the

holder to raise the sample cell. The riser decreases the light path length resulting in increased

linearity in measurement of high turbidities. Calibration of the equipment is based on

Formazin and unit of measurement is FTU. The sensing range is changed by turning the

range switch on the panel.

Procedure

The Turbimeter was switched on and allowed to warm up for 110minutes before taking any

measurements. 30ml of the sample was than pipetted into a clean sample cell. The sample

was then compared to the given standards and one having turbidity closest but greater than

that of the sample chosen. The turbidity was read in units of FTU. (Formazin Turbidity Units.

The guideline value set for aesthetic quality of water is 5NTU (Nephelometric turbidity

units).

e) Total hardness


i. Ammonia buffer solution

ii. N/50 EDTA solution

iii. Total hardness indicator tablets.

59

Procedure

50 ml of the sample was pipetted into a conical flask, 1 ml of ammonia buffer solution and

one total hardness indicator tablet (crushed with one rod end) were added. Standard N/50

ETDA solution was titrated with constant stirring until the colour changed from purple to

blue. Total hardness was calculated as mg CaCO3/l (=ml EDTA×20)

60

APPENDIX B: QUESTIONNAIRE

Please fill out the following survey questions. We are collecting information on the current

water situation we can better aid the Misuuni Village with their water crisis. This survey is

completely anonymous, the information you supply will be completely confidential and used

only for us to better understand the local area.

Family

1.) How many people live in your home?

Male Members____ Female Members____

Water Source

1.) Where do you get your water from (Check all that apply)?

Piped Water Public Tap

Clean Well Clean Spring

Rainwater Collection Bottled Water

Water Truck/Cart Surface Water

Other ________

2.) What is your main source of water?

_____________________________________________________

_____________________________________________________

61

Water Consumption

1.) Do you farm?

Yes No

2.) If you do farm, list the crops you produce.

_____________________________________________________

_____________________________________________________

3.) How much of each crop do you produce?

_____________________________________________________

_____________________________________________________

4.) Do you have anyone who helps with the farming?

Adult Males____ Adult Females____

Youth Males____ Youth Females____

5.) How do you irrigate your crops?

_____________________________________________________

____________________________________________________

62

Health

1.) What is the water quality (directly from the source)?

Please circle the colour your water most resembles

Are there many particles (dirt, gravel) present in your water?

Yes No

Please describe the taste of your water (Metallic, bitter, sour)

____________________________________________________

____________________________________________________

____________________________________________________

2.) Have you ever felt that your drinking water made you ill?

Yes | No

3.) Did your sickness cause you to miss work/school?

Yes | No

If yes, how many days did you miss? _________________

4.) Do you know anyone who has felt sick from drinking water?

Yes | No

___________________________________________________

63

5.) If you were sick, what type of treatment did you receive?

Health Post/Hospital

Home Treatment

No Treatment

Other (Specify) ____________

_____________________________________________________

Water Usage

1.) Do you store your water at home?

Yes No

If so, where do you store it? _______

How much water do you have in storage? ______

____________________________________________________

2.) What does your family use water for?

(_____ Washing Clothes) (___ Bathing) (___ Cooking)

(____ Drinking) ( _____ Farming)

(_____ Other-[Please Specify _______])

64

Water Retrieval

1.) How often does your family go to retrieve water?

________________________________________________

2.) How long does the collected water last?

________________________________________________

3.) Who retrieves this water?

________________________________________________

4.) List any difficulties you have had while retrieving water (Hazards/Obstacles)

________________________________________________

________________________________________________

________________________________________________

5.) What type of containers do you use to carry water? Please describe the containers; are

they used for anything else? How clean are they?

________________________________________________

________________________________________________

________________________________________________

65

Water Filtration

1.) Do you treat your water?

Yes No Don’t Know

2.) If yes, how do you treat it (Select all that apply)?

Boiling

Water Filter

Let it stand and settle

Strain it through a cloth

Bleaching

Let it sit in the sun

Other ________

___________________________________________________

General Comments

If you have any comments or questions about the survey please put them below.

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

66

APPENDIX C; Manos Unidas Borehole Usage Log

67

APPENDIX D; Water Quality Standards (EMCA)

68

APPENDIX E; Independent Test Results

Manos Unidas

Borehole

Kathuku Dam Rain Water

Collection

Misuuni

Alkalinity 240 40 40 240

E. Coli No Trace Count; 19 Count; 7 Count; 7

Table 6-1 Independent Test Results by EWB-USA team

69

APPENDIX F; WRMA FORMS

1. Application for search for water permit

70

2. Ground water/Borehole Form

71

3. Borehole Completion Certificate

72

4. Borehole completion record

73

74

75

76

77

5. Application for water permit

78

79

80

81

82

APPENDIX G: MAP OF THE PROPOSED BOREHOLE PLUS

SUPPLY SYSTEM

KEY;

Yellow: School

Red Cross: Health Centre

Blue: Rivers access points

1- Kathaana River

2- Muvaa River

83

3- Mvaa River

Green: Existing Boreholes

1- School Borehole

2- Patrick Mailang’a’s

3- Borehole 3- Manos Borehole

Purple: Dam

1- Usiumu Dam

2- Misuuni Dam

3- Mbiti Dam

4- Kathuku Dam

Red: Proposed Water Taps (except for Manos water point)

1- Miumbuni Water Point

2- Kavoi Water Point

3- Ngatata Water Point

4- Ngiti Water Point

5- Manos Water Point

Blue Pin: Proposed Drill Site

84

APPENDIX H; Quotation for borehole drilling

85

86

87

APPENDIX I; Photos

88

89

90

APPENDIX J; SSFs - FURTHER DETAILS

Working Principle

Freshwater flows through a sand-bed with a thin layer populated by

microorganisms. Hereby, the water gets purified through various

biological, physical and chemical processes.

Capacity/Adequacy Primarily small, rural communities due to large land requirements

Performance

Removes turbidity, protozoa, pathogens, viruses and heavy metals.

100–300 litres per hour per square metre of surface)

Costs 100–300 USD per square

Self-help

Compatibility

Very high

O&M Simple, low costs

Reliability Very high if properly operated and maintained

Main strength

Simplicity; can be constructed, operated and maintained by the

community; often no need for pumps/electricity

Main weakness

Large land requirements; excessive turbidity (>30 NTU) in the fresh

water can cause the filter to clog rapidly (BRIKKE & BREDERO 2003)

Table 6-2 Features of SSFs


http://www.sswm.info/glossary/2/letterm#term368




http://www.sswm.info/glossary/2/letterh#term115

http://www.sswm.info/glossary/2/lettero#term382



91

Figure 6-1Illustration of a slow sand filter with a regulating valve and a subsequent reservoir

Figure 6-2 Principle of a slow sand filter

92

APPENDIX K; Hydro-geological survey report for proposed

borehole site

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

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