Water Supply Distribution System Design in Ethiopia

This report targets on the design of water supply system for warder town. The objective of this project is to provide adequate, good quality, safe and sustainable water for warder town based on primarily source of water (ground water). The general information of the area, including its location, climate condition, and other important additional information’s are described in the first chapter, i.e. the introduction. This chapter also includes General and specific objectives of the project as well as the methodology; by which the project is undertaken the demand analysis part has taken through which per capita per head as well as the total population. Societal demands are analysed and this based on the ultimate design horizon demand, potential alternative sources of water are identified and the corresponding facilities that enable to utilize the respective source will be designed in order to obtain the most feasible option.

The report gives also emphasis for the design of the pumps as the central and key part of the design procedure. In connection to this the reservoir capacity and the design procedure of the reservoir. The last to come is the Environmental and social impact assessment session which will be briefly at the end of the report. Water supply is among the most essential natural requisites for sustenance of living things. As States without water, life on earth could be impossible. No living thing such plant, Animal or human live without this precious liquid. Water is essential not only for survival but also contributes immeasurably to the quality of our lives.

Provision of adequate water supply and sanitation services for the Urban and Rural population is a major concern regarding the development and enhancement of reasonable conditions of social Welfare. Therefore, the provision of safe, clean, sufficient and potable water and disposal of garbage and undesirable material has become an important factor to live with. This is the main responsibilities of the water Engineers Especially water resource and irrigation Engineers to design, construct, operate and maintain the water supply. Ethiopia is very well known for its enormous potential all of which is generated in its own tertiary and it is still known the water tower of Africa. However, most of the Ethiopian towns have a problem of adequate and potable supply of water. In pursuance to the above goal, Warder Town Water Supply Project is formulated.

TABLE OF CONTENTS

ACKNOWLEDGEMENT

ABSTRACT

ABBREVIATIONS AND ACRONYMS

LIST OF TABLES

LIST OF FIGURES

CHAPTER ONE
INTRODUCTION
1.1. General Project Description and Background
1.2. Objectives of the project
1.2.1. The general objective
1.2.1. The Specific objective is as described here below;
1.3. Location, and Accessibility
1.4. TOPOGRAPHY and Climate
1.5. Physiography
1.6. Significance of the study

CHAPTER TWO
SOCIO-ECONOMIC SITUATION OF WARDER TOWN
2.1 General
2.2 Approach and methodology for socio economic study
2.3 Current Population
2.4 Health and Sanitation
2.4.1. Health Situation
2.5 Access Road and Other Infrastructures
2.5.1 Road and Drainage Network
2.5.2 Telecommunication Service
2.5.3 Transportation
2.5.4 Electric Power Supply
2.5.5 Market Service

CHAPTER THREE
POPULATION FORECASTING
3.1. Design Period
3.1.1. Factor affecting design period
3.2. Design Horizon
3.3. Population Forecasting
3.3.1. Population projection
3.4. Base population of the town
3.5. Population and Domestic Demand
3.6. Methods of population forecasting
3.6.1. Geometrical increase method

CHAPTER FOUR
WATER DEMAND AND WATER CONSUMPTION
4.1. Existing water supply
4.1.1. Introduction
4.1.2. Water Sources
4.1.3. Reservoirs
4.1.4. Distribution Network
4.2. Water demand assessment (Future)
4.2.1. General
4.3. Water demand
4.4. Water Demand Assessment
4.5. Domestic water demand
4.5.1. Population distribution (Projection of per capital water demand) by mode of service .
4.5.2. Establishment of per capita water demand for each mode of service
4.5.3. Domestic (House hold) demand
4.5.4. Adjustment for climate
4.6. Livestock Water Demand
4.7. Non-Domestic Demand
4.7.1. Industrial demand
4.7.2. Institutional demand
4.7.2.1. Educational demand
4.7.2.2. Health institutes
4.7.3. Prisons
4.7.4. Public and governmental offices: -
4.7.5. Commercial demand
4.7.6. Fire Demand
4.8. Losses and Wastes
4.9. Variation in rate of consumption
4.10. Design of pipelines
4.10.1 Design of Rising Main diameter
4.10.2. Design of delivery Main diameter

CHAPTER FIVE
SOURCE OF WATER
5.1. General
5.1.1. Source of water supply
5.2. Ground sources
5.3. Potential water sources of the town
5.3.1. Deep Ground water
5.4. Water Source Selection

CHAPTER SIX
PUMPS
6.1. General
6.1.1. Purpose of pump
6.1.2. Classification of pumps
6.1.3. Selection of A pump
6.2. Centrifugal pumps
6.2.1. Comparison between Vertical spindle pump and submersible pump
6.2.2. Position of pumping station and service Reservoir
6.3. Economical pumping Mains Diameter
6.3.1. Calculation of Economical Diameter
6.4. Pumping power
6.4.1. Pumping power calculation

CHAPTER SEVEN
SERVICE RESERVOIR
7.1. General
7.2. Service Reservoir Necessity
7.3. Design capacity and location
7.4. Reservoir type
7.5. Accessories of Service Reservoirs
7.6. Depth and shape
7.7. Reservoir Capacity Determination

CHAPTER EIGHT
DISTRIBIUTION SYSTEM
8.1. General
8.2. Lay out of Distribution system
8.3. Design procedure of the distribution system
8.4. Selection of pipe material
8.5. Design of pipe lines
8.6. Pressure in the distribution system
8.7. Nodal Demand computation
8.8. Appurtenances

CHAPTER NINE
ENVIRONMENTAL AND SOCIAL IMPACT ASSESSMENT (ESIA)
9.1. Introduction
9.2. Objectives the ESIA Study
9.2.1. General Objective
9.2.2. Specific Objectives
9.3. Environmental Considerations for Development Projects in Urban Areas
9.4. The Scope of the Environmental Study
9.5. Methodology of ESIA
9.6. Description of the Existing Environment of Warder Town
9.6.1. Physical Environment of Warder town
9.6.1.1. General
9.6.1.2. Socio-Economic Environment
9.7. Policy, Legal, Institutional and Administrative Frameworks
9.7.1. NATIONAL Policies and Strategies
9.7.1.1. The Constitution of FDRE
9.7.1.2. Conservation Strategy of Ethiopia (CSE)
9.7.1.3. Environmental Policy of Ethiopia (EPE)
9.7.1.4. Policies on Land Tenure, Expropriation and Compensation
9.7.1.5. Water Supply and Sanitation Policy
9.7.1.6. Ethiopian Water Resources Management Proclamation, No 197/2000
9.7.1.7. Wildlife Policy
9.7.1.8. Forest Policy and Strategies
9.7.1.9. National Population Policy
9.7.1.10. National Policy on Women
9.7.1.11. National Environmental Impact Assessment /EIA/ Procedural Guidelines
9.8. Environmental Impacts
9.8.1. General
9.8.2. POSITIVE Impacts On the Bio-Physical and Social ENVIRONMENT
9.8.3. Detrimental negative impacts on the bio-physical and social environment
9.8.4. Mitigation measures
9.8.5. The CEQ regulations provide the following example of mitigation

REFERENCES

ABSTRACT

This report targets on the design of water supply system for warder town. The general information of the area, including its location, climate condition, and other important additional information's are described in the first chapter, i.e. the introduction. This chapter also includes

General and specific objectives of the project as well as the methodology; by which the project is undertaken the demand analysis part has taken through which per capita per head as well as the total population. Societal demands are analysed and this Based on the ultimate design horizon demand, potential alternative sources of water are identified and the corresponding facilities that enable to utilize the respective source will be designed in order to obtain the most feasible option The report gives also emphasis for the design of the pumps as the central and key part of the design procedure. In connection to this the reservoir capacity and the design procedure of the reservoir. The last to come is the Environmental and social impact assessment session which will be briefly at the end of the report.

ABBREVIATIONS AND ACRONYMS

ADD Average daily demand

CSA Central Statistical authority

SRS Somali regional state

MoWR Ministry of water resources

EIA Environnemental Impact Asses ment

EIS Environmental Impact Solutions

HC House connection

M.A.S.L Meter above Sea Level

ML million liters

L/C/D Liter per capita per day

PF Public Fountains

GTP I growth and transformation plan-I

GTP II growth and transformation plan-II

PVC Polyvinylchloride

YC Yard connection

NW-SE north-west, south-east

NP nominal pressure

LIST OF TABLES

Table 1. Design Life for Major Components

Table 2. medium variant growth rate (%) for SRS

Table 3 population projection using geometric increase method

Table 4. Projected population

Table 5. population percentage

Table 6. Connection profile

Table 7. Per capita demand per day (l/c/day) by mode of service

Table 8. Domestic demand projection

Table 9. Adjustment factors for climate

Table 10 Adjustment factor for socio-economic condition

Table 11 livestock water demand

Table 12. Non-Domestic Water Requirements public and commercial users

Table 13. Summary of day schools

Table 14. Number of student-teacher ratio

Table 15. Demand projection of students and teachers attending day schools

Table 16. Water demand projection for health institute projection

Table 17. water demand projection for prisons

Table 18. Water demand projection for governmental offices

Table 19 commercial water demand

Table 20. Summary of Non-domestic water demand (m3/d)

Table 21 Percentage of losses

Table 22 Max. Day demand (MDD) and peak hourly demand (PHF) population

Table 23. Summary of total water demand

Table 24 description of existing wells

Table 26 Reservoir capacity computation for phase I

Table 27. Reservoir capacity computation for phase II

LIST OF FIGURES

Figure 1 and 2 have been removed by GRIN for copyright reasons

Figure 1: Location Warder town and surroundings

Figure 2 Physiographic map of warder area

Figure 3. Procedures of socio-economic study in the town

Figure 4. Population growth rate

Figure 5 graphical summary of demand

Figure 6 graph of mass curve for phase I

Figure 7 mass curve graph for phase II

CHAPTER ONE

INTRODUCTION

1.1. General Project Description and Background

Water supply is among the most essential natural requisites for sustenance of living things. As States without water, life on earth could be impossible. No living thing such plant, Animal or human live without this precious liquid. Throughout history, water has been people's slave and their masters. Great civilizations have risen when water supplies were plentiful. They have fallen when these supplies failed. People have killed one another for a muddy water hole. Water accounts for about 65% of our body weight. If we lost as little as 12% of it, we would soon die. Water is essential not only for survival but also contributes immeasurably to the quality of our lives. Provision of adequate water supply and sanitation services for the Urban and Rural population is a major concern regarding the development and enhancement of reasonable conditions of social Welfare. Therefore, the provision of safe, clean, sufficient and potable water and disposal of garbage and undesirable material has become an important factor to live with. This is the main responsibilities of the water Engineers Especially water resource and irrigation Engineers to design, construct, operate and maintain the water supply. Ethiopia is very well known for its enormous potential all of which is generated in its own tertiary and it is still known the water tower of Africa. However, most of the Ethiopian towns have a problem of adequate and potable supply of water. In pursuance to the above goal, Warder Town Water Supply Project is formulated.

Safe drinking water is one of the basic necessities for human beings. However, billions of people especially in the developing countries have no access to it at required level of service. Of this women and children are the most vulnerable segments of the society.

To improve this situation, the international community adopted the Millennium Development Goal (MDG) and committed to reduce by half the proportion of people without sustainable access to safe water and basic sanitation by 2015. As the main development objective of the Ethiopian Government is poverty eradication, the country's development policies and strategies are geared towards this end. The provision of safe and adequate water supply for the population has far reaching effects on health, productivity, quality of life, and at large to reduce poverty and ensure sustainable socio-economic development. In 2005 the government of Ethiopia has ratified Universal Access Program (UAP) that enables to provide safe water to all citizens of the nation.

In addition, the first Growth and Transformation Plan (GTP-1) covering the period from 2011 to 2015 was also endorsed in 2010.

As the first growth and transformation plan was finalized in the mid of 2015, the Second Growth and Transformation Plan (GTP-2) covering the period from 2016-2020 is prepared. As the country has a vision to reach to a level of middle income country in its socio-economic development by the year 2025, the plan is prepared taking into consideration this national vision. Hence, the main focus of the plan related to water, supply, sanitation and hygiene is to ensure availability of water supply and sanitation services that satisfies the need of middle income countries' citizens by the year 2020. For this purpose, the experiences of some middle income countries such as Indonesia, Vietnam, Ghana, and Kenya which have some similarities to our country in demography, population settlement patterns, etc. is reviewed and their best experiences and achievements are used to set the objective of the plan.

The core strategic directions of GTP-2 related to water supply, sanitation and hygiene sector are:

- Upgrade the water supply service infrastructure to the level of middle income countries by 2020.
- Increase the water supply access coverage upgrading the service level.
- Ensure good governance improving sustainability, effectiveness and efficiency of water supply services.
- Build the sub-sector's implementation capacity.
- Build effective and efficient civil service development army through strengthening the civil service reform program.
- Empower women including decision making.
- Ensure urban water supply customers' satisfaction by enabling the water supply utilities financially self-sufficient including investment cost recovery and ensuring good governance in the service delivery.
- Establish urban wastewater management system.
- Encourage use of labor intensive low cost technologies using renewable energies such as wind and solar and utilize piped system water supply technologies in urban areas and in rural areas where there are significant number of settlers such as Kebele centers.
- Facilitate enabling environments for the private sector to import substitution manufacturing.
- Provide due support to build implementation capacity of pastoralist regions.
- Provide due focus to community mobilization.

Having the above directions, the sectorial plan has drawn general & specific objectives with defined goals as indicated in the following figure here below.

As per the GTP-2 water supply service level standard for towns, categories of towns is prepared as indicated here below;

- Category 1 towns/cities (towns/cities with a population more than 1 million),
- Category 2 towns/cities (towns/cities with a population in the range of 100,000-1million),
- Category 3 towns/cities (towns/cities with a population in the range of 50,000 -100,000),
- Category 4 towns/cities (towns/cities with a population in the range of 20,000-50,000)
- Category-5 towns/cities (towns/cities with a population less than 20,000)

In general terms, GTP-2 for the sector has one general objective, four specific objectives and 20 goals for rural and urban water supply and sanitation services.

As this study is for town water supply and sanitation service (category 4) town in the case of warder,

1.2. Objectives of the project

The objective of this project is to provide adequate, good quality, safe and sustainable water for warder town based on primarily source of water (ground water).

1.2.1. The general objective

Is as described here below;

The main objective of the study is to assess the challenges of potable water supply and distribution system in Warder town. The overall objective of the project is to design safe adequate, accessible and sustainable water supply system for the proposed design periods for town there by improve the health condition of the community and increase productivity.

The town is under the deficit of water, from the fact that the existing system does not satisfy the water requirement of the tremendously increasing population of the town. The objective of the project is to identify the suitable source to fulfill the demand of the swiftly increase population both in quality and quantity at a reasonable cost without affecting the environmental circumstance of the project area.

1.2.1. The Specific objective is as described here below;

The specific objectives of the project are:

- To access water demand of warder town
- Identification of potential water sources
- Design and selection of pump
- To design conveyance system for water supply scheme of warder town
- To design reservoir capacity of the system

1.3. Location, and Accessibility

Warder town is the administrative centre of Dollo zone, which located in Somali regional state. The town extends from769,000m to 774,000m N and 536,000m E to 540,000mE UTM with in 38N.The Highway Asphalt road 478Km from Jigjiga to kebredhare is accessible throughout the year but the rest 126 Km to Warder is not accessible during Rainy season.. Has altitude and longitude of 6.58oN 45.21oE and elevation of 541 m.a.s.l

This figure has been removed by GRIN for copyright reasons.

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Figure 1: Location Warder town with and surroundings

Source: - Somali regional state administration map

1.4. TOPOGRAPHY and Climate

The topographic feature is a direct result of the wide physiographic setting. Warder plain is dominantly characterized by flat to undulating topography dissected into tablelands features. The Ogaden has an elevation above sea level that ranges from 1,500 metres in the northern Somali platu near to Dire Dewa, falling to about 300 metres along the southern limits and the receiving as much as 500-600 mm of rainfall annually. More typical of the Ogaden is an average annual rainfall of 350 mm and less. The landscape consists of dense shrubland, bush grassland and bare hills. The climate is hot, arid to semiarid, corresponding to the Ethiopian bereha climatic zone .Ogaden basin relatively considered as dry in most cases with seasonal river flows.

1.5. Physiography

Physiography of catchment provides a limited surface area within which physical processes pertinent to the general hydrology may be considered. The climatic variables and the water and sediment discharge, water storage, and evapotranspiration may be measured, from these measurements, denudation rates and moisture and energy balances may be derived, each of which is useful in the consideration and understanding of landscape formation. The assessment area found within The Ogaden Basin, which is located on the Somali Plateau, southeast Ethiopia. Ogaden Basin Physiographical bordered with Wabi Sheble basin on the west and Awash basin on the north.

This figure has been removed by GRIN for copyright reasons.

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Figure 2 Physiographic map of warder area

Source: - feasibility study on warder town

1.6. Significance of the study

Studying the extent and coverage and dynamics of urban water supply service in warder helps to identify the pressing problems in service delivery. This study is expected to increase the knowledge and up to date information on the city water supply size and its undesirable impacts on the urban community due to shortage of water supply. It will also serve as a working document to policy makers in the water sector of Somali Regional state (SRS), especially policy making bodies, and the Warder town water supply and sanitation authority and the Nongovernmental organizations (NGOs) which have interest in assisting warder town with financial and technical support in the area of urban water supply. Moreover, the finding will further serve as reference data and it opens avenue for any further investigation in the area, and as a useful material for academic purposes.

CHAPTER TWO

SOCIO-ECONOMIC SITUATION OF WARDER TOWN

a. General

The town's administration is divided into four Kebeles named as Kebeles 01, 02, 03 and 04.

The consultant has conducted the socio-economic study in the town using, the approach and methodology described here below to come up with the required findings described in the sub­sections here below.

b. Approach and methodology for socio economic study

The method that the consultant uses to conduct socio-economic in the town is unique. The consultant uses a two stage process to carry out the study. The study starts at each block with the general and particular information in each block included, and then conducts detail study at each block related to the economic standards of the dwells selecting random samples from each block. The study was carried out with the process as indicated in the figure here below;

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Figure 3.Procedures of socio-economic study in the town

The socioeconomic study in the town classifying the information in to three major groups described as;

1. Summarized socio-economic related information in each blocks within each village and Kebele of the town, and
2. Detail socio-economic house hold survey for domestic users covering at least 10% of the total Households in the town.
3. Detail data collection on 100% of the non-household users in the town.

c. Current Population

According to the study the total current population of the town is about 21,425

According to the Federal Democratic Republic of Ethiopia Central Statistical Agency Population projection values for 2009 at Zonal and Worde levels by rural residence, the projected population for Warder town is estimated to be 12,018.

Evaluating the above figures, consulting the local authorities and considering the special facts on the ground, the client has approved the design base population to be 21,425. Hence, the consultant has prepared this design taking this figure as a base for year 2011 E.C.

d. Health and Sanitation

2.4.1. Health Situation

The health system in Ethiopia is under-dimensioned. Most people live in rural areas with little access to any type of modern health care. It is estimated that 75% of the national population suffers from some communicable disease and malnutrition, major causes of death (DHS 2008). Mothers and children are the most exposed. Infant and maternal mortality rates are as high as 96.8 per 1000 live births, and 850 per 100,000 live births, respectively. High birth rates spearhead Ethiopia among Africa's populous countries, boosting the demand for health services, which are bogged down by the shortage of trained staff and medical supplies. The most common diseases in the town of Warder are RTI followed by Diarrhea and UTI (as shown in the table here below). RTI is covering up 38.65% of health-unit visits, is a common cause of outbreaks. In the town there is one health institution that is owned and run by government serving the residents of the town and periphery communities who reside in rural villages. There is one Referral Hospital which is under construction in the Town.

The Health Centre has well documented evidence on the most common diseases and infections associated with poor water supply and sanitation services. In the last two years, water borne and water related diseases which are mostly affecting children less than 5 years old were skin diseases, intestinal parasites and diarrhea.

e. Access Road and Other Infrastructures

2.5.1 Road and Drainage Network

The road and access route network in the Town is not well organized. The new roads networks as per the official development plan are not all opened.

The town has no drainage system at all as the run off due to rain is also small.

2.5.2 Telecommunication Service

Telecom service is one of the major means by which people interact with in and outside the town for the different purpose. The town has mobile network communication facility.

2.5.3 Transportation

In Warder town there is bus transportation service between Jigjig and Warder three times in a week.

2.5.4 Electric Power Supply

In the town there is no electric power supply, but the town uses diesel generator from 5:00 PM to mid night.

2.5.5 Market Service

There is only one Market place in Warder town that is primary market (Ferfeda). The secondary markets are held at village level, opened every day for trading commodities. The secondary market held in the open locations. A range of commodities is traded in the market which includes household food, and other consumable offered by outside traders and farm products such as grains and livestock products offered by the farmers. The quantities of farm products are small and purchased by local consumers.

CHAPTER THREE

POPULATION FORECASTING

3.1. Design Period

Design period is the number of years for which the design of water works has been done. Before designing & construction of water supply scheme, it is necessary to assure that the water works have sufficient capacity to meet the future water demand of the town for the fixed design period. The design period should be either long or short. A water supply scheme shall, almost without exception, supply for a requirement which is continuously increasing with the coming years. Hence a new water supply scheme is normally made large enough to meet the needs of growing communities for an economically justifiable number of years in future. Huge and costly construction works like dams, reservoirs, treatment plants and distribution pipelines are required for a complete water supply scheme. These works cannot be replaced easily and conveniently for future expansion. Hence these works should be designed for sufficient capacity to meet the future demand of the town for an established span of time. This span of time or the number of years for which the design of the water supply works is done is known as design period. The design period should neither be too long that the financial burden is thrown on the future generation nor should be too small that the whole financial burden is thrown on the present generation and the design of water work becomes uneconomical. The design period is not only limited by general economic consideration but also the following factors.

3.1.1. Factor affecting design period

- Funds available for the completion of the project if more funds are available design period may be more, but if small funds are available the design period shall be less.
- As far as possible the design period should be nearly equal to the construction materials used in the water supply work.
- Rate of interest on the loans taken to complete the project.
- Life of structural materials used in construction
- Anticipated expansion of the town

3.2. Design Horizon

- 20 years' design period

The design periods of most of different components is summarized in Table below.

Table 1. Design Life for Major Components

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Source: Design criteria MoWR (2006)

3.3. Population Forecasting

The term forecasting is reserved for those circumstances in which additional information on future changes in technology society and even the regional and national economy are incorporated. The production of accurate demand forecast is a prerequisite to successful water resource planning. After the design period is fixed the next step is to determine the population in various periods because the population of towns generally goes on increasing since population is always a relevant factor to estimated future water demand, it is necessary to predict in the same manner what the future population will be. The data in the future for which the population is made depends on the particular component of the system which being designed. Elements of the system which are relatively easy to expand tend to have shorter design lives, hence population projection periods may range from 19-30 years. Determination of population is one of the most important factors in the planning. If the project has to serve the community for certain design period. What will be the population at the end of the design period is the basic question. This can be achieved by using various methods for population forecast.

3.3.1. Population projection

In order to predict the future population of a certain town, it is necessary to know the factors affecting its population distribution, size and growth rate. The major factors that accounts for changes in population are births, death and migration. All these factors are influenced by social & economic factors and conditions prevailing in the various communities among which the important ones are:

- Family planning practice
- Spread of education
- Development and advancement of medical facilities
- Industrialization and commercialization of a town
- Factors like war and natural disaster

While designing water supply facilities, one must recognize that the various units are adequate to serve the present as well as the future population. Therefore, population projection is one of the important factors, which greatly influences system unit capacity. Knowing the base population of a town along with some indications on future growth trend would enable to design a reliable and sustainable water supply system. Adopting erroneous and non-reliable base population figure and formulating nonrealistic growth rate assumption would lead to either over designed scheme which have an impact on capital investment cost or under designed scheme which does not serve the purpose it is planned for. Hence, in order to avoid or minimize the aforementioned population related risks, efforts have been made to review & justify the credibility of the available population and growth rate figures.

3.4. Base population of the town

Since a town or city population determines water requirements for the purpose of water supply system, an exact population of the town is categorically necessary. It includes all peoples, who utilize water for drinking, washing clothes, cooking, bathing, cleaning utensils and watering animals. According to the study the total current population of the town is about 21,425.

Consulting the local authorities and considering the special facts on the ground, the client has approved the design base population to be 21,425. Hence, the consultant has prepared this design taking this figure as a base for year 2011 E.C.

3.5. Population and Domestic Demand

Population Growth Rate

In order to avoid over or under estimation of the future population, medium variants growth rate is adopted for Somali Regional State region according to the 1998 CSA Analytical Report by CSA up to the year 2030. The following table shows the growth rates adopted for the future population projection of the medium variants.

Table 2.medium variant growth rate (%) for SRS

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Source” CSA 1998 Analytical Report

Factor affecting population growth

- Accident in the nature of big fire, epidemic, floods, earth quakes, wars etc.
- Changes in educations, politics, recreation etc.
- Economic changes, development of new industries etc.
- Increase in transport and conveyance faculties.
- Unforeseen circumstance such as discovery of oil, mine etc.
- Sudden increase in religious importance of the city
- Starting of project of national importance in or around the city
- Political changes in the adjoining country and nearness to the national borders.

3.6. Methods of population forecasting

There are several methods for population forecast. But the judgment must be exercised by the engineer as to which method is most applicable for a particular location. Followings are some of the important methods of population forecasts or population projections.

Methods used to forecast future populations of a town are: -

- Arithmetic increase method
- Geometric increase method
- Incremental increase method
- Decreasing rate method
- Method used by Ethiopian Statistics Authority(CSA)
- Master plan curve method
- Ratio &correlation & others...

For the selection of best methods, we have considered the following factors: -

- Availability of data for calculating of the future population.
- The incremental situation of the population from decade to decade or from year to year.
- The oldness or wideness of the cities or the towns.
- The increment of population due to migration under estimation of the population and percentage error etc.

The knowledge of population forecasting is very important for design of any water supply scheme. The design of the water supply project is done on the basis of projected population at the end of the design period. Otherwise the present scheme may be inadequate in the near future.

3.6.1. Geometrical increase method

In this method it is assumed that the percentage increase in population from decade to decade remains constant. If the present population is Po and average percentage growth is k, the population at the end of n decade will be

Abbildung in dieser Leseprobe nicht enthalten

This method is mostly applicable for growing towns and cities having vast scope of expansion.

Sample calculation

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Table 3 population projection using geometric increase method

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This method is mostly applicable for growing towns and cities having vast scope of expansion.

Table 4.Projected population

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From all population forecasting methods, the geometrical has been found more suitable for warder town. Hence population at the end of the design period (2031 E.C) is 43,463

Table 5.population percentage

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CHAPTER FOUR

WATER DEMAND AND WATER CONSUMPTION

4.1. Existing water supply

4.1.1. Introduction

The existing water supply system was examined in close cooperation with the representatives of the warder town water office regarding the field of production transmission storage and distribution of water as the feasibility study.

In general, the existing system is more or less in functional condition but executed on a quite low technical stand.

4.1.2. Water Sources

According to the feasibility study the town is supplied with water from four boreholes the boreholes. Since the boreholes are 5km apart there is one stand by generator which is being used in case of electrical power interruptions.

From these boreholes the water is pumped via one 4'' PVC pipe (length: approximately 2km) in to a 250m3 elevated concrete reservoir, which is located close to the municipality office at the eastern edge of the town.

4.1.3. Reservoirs

As mentioned before there is one reservoir in the town located near the municipality office. The first one is a 250m3 elevated concrete reservoirs.

The reservoir does not have control equipment. There is no disinfection facility at the reservoir site which means that the water is being distributed to population without any chlorination.

4.1.4. Distribution Network

The distribution network consists of galvanized steel and PVC pipes with a diameter ranging between 2'' and 4'' and an estimated length of about 2km. For the existing network no data or plans are available. However, a consultant in association with the town's water supply office plotted the existing network on the master plan of the town in order to analyze the efficiency of the system.

4.2. Water demand assessment (Future)

4.2.1. General

A water supply system capable of supplying sufficient quantity of portable water is necessary for city or town. In order to estimate as correcting as possible, the total demand of a particular community, all demands must be considering. Generally, speaks in design the water supply scheme. For a town, it is necessary to determine the total quantity of water required for various proposes. Some of the factors that affect water demand are: -

Climatic condition size of the town, culture of people industries cost of wale, fault of water pressure in the distribution system, system of supply etc.

1. Climatic condition: - Water consumption during summer is more than winter during summer everybody taxes both twice and thrice, clothes also become dirties, more water is used for drinking and more water s consumed, in running coolest. This is why we say water consumption is much more in summer than in winter,
2. Size of the town: - Generally, the demand of water per head will be more on big city than that in small city. In big cities lot of water is required for maintaining clean and health environments while in small towns more or less small.
3. Culture of people: - High class community uses more water due to their better standard of living and high economic status. Middle class people uses water at average rate and for poor people a single water tap may be sufficient for several families.
4. Industries: - more water is used in highly industrial city
5. Cost of water: - If cost of water is high, the water demand will be less Hence the rate at which water is supplied to consumer may affect the rate of demand.
6. Quality of water: - A water work system having good facility and portable water supply will be more popular with consumers.
7. Pressure in the distribution system: - There would be of great importance in the case of localities having number of two or three storied buildings. Adequate pressure would mean an uninterrupted and constant supply of water.
8. System of supply: - The system of water may be continuous or intermittent. In continuous system water is supplied all 24 hours. While in the case of intermittent system water is supplied for hours of the day only results in some reduction in the consumption. This may be due to decrease in loss and other waste of full use.
9. Method of charging: - In a town where meters are used less quantity of water will be used than in towns without meters in their system. A metered supply ensures minimum of waste as the consumer then know that he was to pay. For water used by him and consequently. It more carefully in use.

4.3. Water demand

Water is normally used for domestic purposes such as drinking, cooking, ablution, washing clothes and utensils and cleaning houses, and for nondomestic purposes such as public, commercial, and firefighting institutions, and livestock watering. In addition unaccounted for water should be considered while calculating the total water requirement of the system.

4.4. Water Demand Assessment

The demand includes domestic, non- domestic (commercial, industrial, institutional, public use etc.), demand due to loss (unaccounted for water), animal drinking and fire demand. Generally, we have the following demands:

a) Domestic water demand
b) Non domestic water demand

- Commercial water demand
- Institutional water demand
- Industrial water demand

c) Animal water demand
d) Compensate losses demand
e) Fire demand

Water consumption for various purposes is divided under the following categories.

1. Domestic demand
2. Public demand
3. Commercial & industrial demand
4. Fire demand
5. System loss
6. Animal water demand
7. Institutional water demand

4.5. Domestic water demand

Domestic water demand includes water used for basic needs including water finished to in- house purpose such as drinking, cooking ablution washing utensil washing clothe, washing toilets, watering animal. The amount of water used for domestic purpose varies depending on the life style living standard, climate mode of service and all the price of water and affordability of users.

In projecting the domestic water demand of warder town the following procedure have been followed.

a) population percentage distribution by mode of service
b) Establishment of per capita water demand by purpose for each mode of service.
c) Adjustment for climate
d) Adjustment by socio - economic conditions
e) Projection of domestic water demand

4.5.1. Population distribution (Projection of per capital water demand) by mode of service

The following common three types of service levels have been adopted for urban centers of Ethiopia.

- HOUSE connections(HC)
- Yard connections(RC)
- Public connections(pc)

The population percentage distribution for each mode of service is determined by sample survey and published statistical data in to consideration. In order to attribute certain characteristics to each town, the towns have been grouped into categories according to their population size.

As per the GTP-2 water supply service level standard for towns, categories of towns is prepared as indicated here below;

- Category 1 towns/cities (towns/cities with a population more than 1 million),
- Category 2 towns/cities (towns/cities with a population in the range of 100,000-1million),
- Category 3 towns/cities (towns/cities with a population in the range of 50,000 -100,000),
- Category 4 towns/cities (towns/cities with a population in the range of 20,000-50,000)
- Category-5 towns/cities (towns/cities with a population less than 20,000)

These categories have been used to determine present and future service levels, as well as present and future per capita consumption for each of the connection type. The population of Warder at end of 2030 E.C (43,463) is in between 20,000 and 5, 0000 so based on the town category grouping the population size of the town lies in category 4 as shown in table above. These categories have been used to determine present and future service levels (connection profiles).as well as present and future per capital consumptions for each of the connection types. Based on the above table, since, our work focused on category 4 the connection profiles as well as present and future per capital demand lies on it.

Table 6.Connection profile

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SOURCE: feasibility study on 25 Ethiopian towns

The projected per capita distribution by mode of service up to 2030 is taken from CSA of 2007

4.5.2. Establishment of per capita water demand for each mode of service

The present per capita water demand in Warder town, as stated in feasibility study is low. The existing water demand is in adequate to satisfy the demand of the community. Per capita demand for any mode of service is determined by adding water requirement of the users for different purposes such as drinking, cooking. Ablution washing dishes, laundry, house cleaning, baths shower etc. According to CSA 2007 the projected per - capita consumption of different mode of service for category 4 is shown below. The adequate water supply level for per capital water demand has to be determined based on basic human water requirements and adjusted to specific condition of each area as required. The basic human water requirement for different use could vary based on the mode of service to be used and the closeness to water supple facility. The following g table shows the composition of the basic human per capital water demand based on need for different use adopted for the estimation of water demand for Warder town.

Table 7.Per capita demand per day (l/c/day) by mode of service

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SOURCE: feasibility study on 25 Ethiopian towns.

4.5.3. Domestic (House hold) demand

Consumption depends on many factor. The most important of which are economic, social and climatic. Consumptions by house hand public

Table 8.Domestic demand projection

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4.5.4. Adjustment for climate

A change in climate is one of the factors which affect the war demand of the population under consideration. Warder town is categorized under warm temperature type of climate mean monthly temperature is 24 0c warder is however about 541 and appropriate climate adjustment factor 1.3 is adopted as it is shown in the following table

Table 9.Adjustment factors for climate

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Source: - data compilation and analysis project (1997)

3 4.4 Adjustment due to socio - economic condition

Socio - economic condition of particular community also plays an important role in determining the water consumption. The design criterion is provided for this in the form of categories for various degrees of development. It is however different to quantity many aspects of development and consequently the classification of particular town is made in relation to the other.

Table 10 Adjustment factor for socio-economic condition

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Source: - 9/25 towns water supply feasibility study and engineering design report

It is obvious that Warder town is grouped under the towns under normal Ethiopia condition. So 1.0 is adopted.

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Therefore, the overall adjustment factors for domestic dials demand consumption is 1.3 And the total domestic water demand projection is calculated in above table.

4.6. Livestock Water Demand

The livestock water demand is considered where there are no traditional sources such as rivers and streams available within a radius of 5 km from the area to be considered for water supply provision. Assumptions in estimating livestock water demand vary from consultant to consultant. Estimating livestock water demand vary from consultant to consultant.

NOR consultant has determined the water requirements of in terms of a weight equivalent name called Tropical Livestock Unit (TLU). The average body weight of one TLU is 250 kg and on average, an animal consumes one liter of water per day for each 10 kg of body weight. Therefore, about 25 liters of water is required daily for each livestock unit. Hence, the daily water demand is estimated by calculating the equivalent TLU estimate of the domestic animals in the project area and multiplying the result with 25 liters.

In other cases the following figures are recommended for average per head per day water demands to be considered for different types of livestock

Warder is one of the areas in the country with acute water shortage for animal watering. In the dry seasons, Pastorals from the surrounding 30km radius are using water for their Animal Watering from the town's water supply system. In designing the future water supply system,. There is no data regarding the number of animals served by the town's water supply system. Thus, the animal water demand is estimated as a percentage of the domestic water demand. It is assumed the animal water demand be 15% of the 2011 domestic water demand and remains constant for the rest of the design periods

Sample calculation

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Table 11 livestock water demand

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4.7. Non-Domestic Demand

Non - domestic demand: - Under this head the quantity of water required for various non - domestic usages, is ascertained non domestic needs, such as hotels, hospitals, schools, office etc. Non- Domestic demandes are : -

- Institutionnel demand
- Commercial demand
- Industrial demand
- Fire demand

For the town warder we are only interested on institutional demand, commercial demand, Industrial demand and fire demand of the town.

Table 12.Non-Domestic Water Requirements public and commercial users

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4.7.1. Industrial demand

The development plans of many towns indicate that there are plans to the development plans of many towns indicate that there are plans to industries are assumed to have their own water supply systems. However, the following values can be taken for some industries.

The following values can be used for the planning purpose in the absence of defined water demands for specified industries:

- 5m3 /ha/day for small industries
- 10m3 /ha/day for large industries
- Where there is no land use plan for the project area, it is recommended take 5 to 10% of the domestic water demand, depending on the size of the project.

In our case 5% of domestic water demand is used as industrial demand

Abbildung in dieser Leseprobe nicht enthalten

4.7.2. Institutional demand

4.7.2.1. Educational demand

The water demand for educational institutes is classified in to

i. Elementary and intermediate schools
ii. Senior secondary school

There are five elementary schools with 6965 no of students, and one senior high school with 1621 students attending day school according to the warder town administration office education desk and the schools themselves. Totally there are 8586 students in 2010 which account, 40.07% of total population of the base year of 2011.

Table 13.Summary of day schools

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Source: - feasibility study on warder town (national WASH) Using the specific student -teacher ratio in Warder Day School

Table 14.Number of student-teacher ratio.

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Source: - feasibility study on warder town (national WASH)

This has a total population of 151 which is added to the number of students which will be 8,737 at 2011.

Table 15.Demand projection of students and teachers attending day schools

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4.7.2.2. Health institutes

In 2011, there is one hospital and one health center in warder town with a total of about 150 beds. The future water demand of hospitals is estimated with the assumption that there will be one bed

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Table 16.Water demand projection for health institute projection

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4.7.3. Prisons

In warder there are 2 prisons accommodating about 2%, 3%, 6% of the population per decades.

Table 17.water demand projection for prisons

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4.7.4. Public and governmental offices:

According to CSA about 51% of the population of Warder town is economically active of which 15.31% are employed in public or governmental officer.7.81% of the population of warder is employed in public or government offices. And their consumption is recommended as 30 l/c/d.

Table 18.Water demand projection for governmental offices

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4.7.5. Commercial demand

Commercial demand includes water requirement for restaurants, Cinema ouses railways, bus stations, hoping centers, Local drinks (Teji, Areqe, Xela) etc where as institutional/public demand includes water required by schools, hospitals, public offices, military camps, public parks, dispensaries, day-care centers and so on. And commercial services, the following water demand figures can be adopted.

In case where exhaustive estimation of the public and commercial institutions are not possible it is recommended to take 20 to 40% of the domestic water demand, depending on the size of population.

The commercial water demand depends on the type and number of commercial establishments. However, the water demand in various types of commercial establishments may vary greatly.

Then, Commercial water demand=15% * total domestic water demand

For 2011 Commercial water demand=15% * 856.46=128.469

Table 19 commercial water demand

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Table 20.Summary of Non-domestic water demand (m 3/d)

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4.7.6. Fire Demand

Fire generally breaks out at commercial centers, stores etc. Big cities which have valuable properties require large quantity of water for fire-fighting. Fire demand is the quantity of water needed to extinguish fire which depends upon population, centers of buildings density of buildings and their resistance to fire. The quantity of water for fighting is small compared to the annual average consumption of water which will not be more than the amount of water distributed during the max day water demand.

For our project what we have done is that 10% of the reservoir has to be considered for firefighting purpose during fire break down beside to accommodating total designed water demand of the town.

4.8. Losses and Wastes

These include the quantity of water due to wastage, losses, thefts etc. i.e.

- Waste in pipe line due to defective pipe joints, cracked and broken pipes, faulty values and fittings.
- Water that lost when consumers keep open their taps and public taps even when they are not using water and allow continuous wastage of water.
- Water that is lost due to unauthorized and illegal connection.

While estimating the total water demand for a town or city, allowance for this losses and wastage should be done from the feasibility reporting it is given that as fellows.

Table 21 Percentage of losses

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Source: - past experience of experiments of 25 towns

4.9. Variation in rate of consumption

The per capita demand which we have calculated in the previous articles, is the over consumption of the years. In practices it has been seen that this demand has not remain constant throughout the year. But it varies from season to season; even form hour to hour, variation rate of demand may be termed as.

- Seasonal or monthly variations
- Daily variation & Hourly variation

1. Seasonal variations: - The water demand varies from season to season. In summer the water demand is maximum.
2. Daily variation: - the rate of demand for water supply may vary from day to day. This is due to habits of the consumers, climatic conditions; holydays etc.
3. Hourly variation: - the rate of demand for water during 24hrs does not remain uniform and it varies according to the hour of the day

Table 22 Max. Day demand (MDD) and peak hourly demand (PHF) population

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Source: - The World Bank Issue Paper For Project, Draft Final Report

Table 23.Summary of total water demand

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Figure 5 graphical summary of demand

4.10. Design of pipelines

4.10.1 Design of Rising Main diameter

The well field water rising main from collection chamber to the booster station. Also the diameter of rising main is obtained from continuity equation. Assumed velocity through the rising main; V=2 m/s (recommended velocity from 0.3 to 2m/s)

Abbildung in dieser Leseprobe nicht enthalten

4.10.2. Design of delivery Main diameter

The well field water rising main from collection chamber to the booster station. Also the diameter of rising main is obtained from continuity equation. Assumed velocity through the rising main; V=2 m/s (recommended velocity from 0.3 to 2m/s)

Abbildung in dieser Leseprobe nicht enthalten

CHAPTER FIVE

SOURCE OF WATER

5.1. General

Water source is the critical part of any water supply scheme. It's important that sources of supply be capable of providing service for both the short term and long term demands being projected. After deciding the water demand of the population at the design period, the next step is to search water source, which may be able to supply the required quantity of water.

There are mainly two aspects on which the success of a water supply scheme depends. These aspects are amount of available water from the source and the amount of water actually needed by the town. The source of water should be such that can provide adequate quantity of water. Availability of water from the source should at least be equal to the demand. Availability of water from a source which may be surface or ground ultimately depends upon rainfall. Rainfall is a natural feature, which may be more in one year and very slack in the next. In drought year, availability of water is minimum. The source of water for water supply schemes should be such which can provide adequate water even during severe drought conditions.

Water sources will be selected to meet the expected maximum day demand for the relevant design period. A 24-hour basis is not mandatory given the need for consideration of maintenance and operation activities when pumping is involved. Gravity system sources, however, should operate 24 hours per day. To have efficient water supply scheme, we require permanent source of water. The capacity of the source should be such as to meet all water requirements of the people. The best available source should be selected for meeting the demand.

The existing water supply source of Warder town is, from two groups of water sources, grouped as;

1. Four boreholes;

a. Three wells dug by the government for dwells of the town all dug in 2000 E.C at different places with one of them serving for town dwellers and livestock and the other two to serve for dwellers of the town, which are also planned to be part of the towns water supply system

b. One private well serving the dwellers of the town

2.7 large diameter hand dug wells, depth ranging from 10-20 meters

a. Three of them for drinking by nearby dwellers of the town,

b. Two of them for livestock use

c. One for both domestic use of nearby dwells and animals

The data on the above wells dug by the government which are planned to be the part of the sources for town's water supply system is not yet found from the Bureau. The Bureau is to organize and deliver the information on above wells following the request by the consultant. The names and locations of the above source with their location is as indicated the table here

Table 24 description of existing wells

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In 2009 E.C., the Bureau has dug a well having a safe yield of 7.5 l/sec. A new system is laid from this wall to the existing reservoir with ND150mm uPVC rising main to the newly constructed reservoir described here below. In addition, there is also a well with 20 l/sec capacity which is not connected to the system.

Water shortage is the major problem with the existing system. Domestic supplies are Supplemented from secondary sources from the river, small springs and hand dug wells

5.1.1. Source of water supply

After knowing the population number and the demand of the town or city the source should be clearly known in quality as well as quantity.

The source of water supply may be generally classified as: -

1. Surface sources
2. Ground sources

5.2. Ground sources

Staged development of boreholes will be considered where more than one borehole is required to meet the anticipated demand. Where access to the well field for future mobilization is not a problem, the number of boreholes adequate to satisfy the maximum day demand for 10 years will be considered if two-stage development is more economical than constructing all boreholes at once. The remaining infrastructure of the well field shall, in any case, be designed for 20 years. Location, depth, diameter and screen position, discharge with the pump depth and specification shall be determined related to the hydro geological investigations. Chlorination of groundwater (springs or boreholes) will be recommended where there is pollution, or risk of pollution, and the source is not, or cannot, be excluded on pollution grounds.

Ground water is important source of water supply which has a number of advantages. They may require no treatment, have uniform temperature thought out the year, are chapter than impounding resource and amounts of water available are more certain. Practically speaking they are not affected by drought in the short run.

Ground water sources are further divided into

1. springs
2. infiltration galleries
3. Wells

5.3. Potential water sources of the town

According to the feasibility study major water sources of the areas (warder town) are: -

1. Deep ground water and
2. Ground water as spring

5.3.1. Deep Ground water

The geological and hydrological investigations around warder indicated that the sand and gravel aquifer interbred in the pyroclastic deposits is some better aquifer. In this aquifer around the town a continuous decline reported in the discharge of walls as a result its unfavorable location of the wells. Therefore, wells located close to the town, which is a water divided would not be sustainable source for the future supply.

1. Quality and Quantity of Ground Water

Generally speaking, the amount of ground water from any source is limited and cannot company with surface supplies. At the same time, it is of a much better quantity and should always be preferred for small populations and moderate water supplies they do not require costly and exhaustive purification needed for surface water.

2. Advantages of Ground Water for water supply

- It is true that when pumping head is large, energy costs may be significantly high. However, if one considers relatively high investment required for hydraulic structure such as dam, weir, canons and pipes, the overall economic pictures will show a clear advantage of ground water.
- Climatic fluctuations in ground water levels are usually small relative to the thickness of aquifer, so that large volume of water stored in the aquifer may serve as aquifer and supply water during dry season.
- Ground water can be supplied to the consumers with little treatment

5.4. Water Source Selection

The process of choosing the most suitable source of water for development into a public water supply largely depends on the local condition. When a spring of sufficient capacity is available, this may be the most suitable source of supply. When springs are not available, or not suited to development, generally the best option is exploring ground water resources for small supplies. The selection of the source of water supply to a town or city depends on the following factors:

1. Location of the water sources
2. Quantity of water
3. Quality of water
4. The cost of the water supply scheme.

1. Location and capacity of the water source

The source should be as near to the town or city as possible. Is ground sources is available to a town, then other deciding factors are also taken into account. Etc.

2. Quantity of water

The source of water should have ample amount of water to meet up all the demands of the city as domestic, industrial, fire resistance, public etc., throughout the whole year. It should also meet the extra quantity of water to be used, in the future if the city is expanded. It should also be able to meet the maximum demand in dry season (Weather).

3. Quality of Water

The quality of water should be such as which can be easily and cheaply treated. It should not contain disease germs which may endanger the human life. Therefore, as far as possible the water of the sources should be whole some, safe and quite free form pollution.

4. The cost of the water supply scheme

While selecting the source the cost of water supply project should also be taken into consideration. The cost depends on many factors as system of supply, ground levels of the town, distance between source and distribution etc. The water flowing under gravity will be cheaper than lifting by pumps. The selection of source of water is done on the above factors, but that source should be selected which is big in quantity and good in quality at the comparative least cost.

Having mentioned the above sources of water supply and criteria for selection the best source is selected by comparing each other as follows: -

- Deep ground water sources: -

In warder there are limited numbers of ground water sites. The advantages of ground water are mentioned above under the subtitle advantages of ground water for water supply.

Out of available bore hole site around warder town, we select for our water supply project site which is situated to the north of warder about 4km close to the highway because of the following reasons: -

- The site has good yield (20l/s)
- Its location only 2 km from the town
- During feasibility study it was checked that the place has sustainable recharge capacity.

CHAPTER SIX

PUMPS

6.1. General

The primary function of a pump is to add hydraulic energy to certain values of fluid. This is accomplished which the mechanical energy imparted to the pump from a power source is transferred to the fluid, there by becoming hydraulic energy. Thus, a pump serves to transfer energy from a power source to a fluid, thereby creating flow or simply creating greater pressures on the fluid.

6.1.1. Purpose of pump

Pumps are used in water works for the following reasons

- To lift raw water from a surface source of supply
- To lift raw water from wells (underground source of supply)
- To deliver treated water to consumer's taper at desired pressure
- To boost line pressure
- To fill elevated storage tanks (distribution reservoirs)
- To supply fire - pressure for fire hydrants
- To back wash filters
- To dewater tanks, basing, sumps etc.
- To provide bailer food
- To pump chemical solutions

6.1.2. Classification of pumps

A general method of classifying pumps on the basis of Engineering design is to divide them in to two groups.

1. Positive dis placement pumps.
2. Variable dis placement pumps

1. Positive Displacement pumps

Those pumps in which the liquid is sucked and then it is actually pushed or displaced due to the thrust exerted on it by a moving member. These pumps usually have one or more chambers which are alternately filled with liquid to be pumped and emptied again.

2. Variable Displacement pumps

The distinguishing characteristic of variable displacement pumps is the inverse relationship that exists between the rate at which they deliver water and the head against which pumping takes place. The greatest impute of power for most variable displacement pumps is required at low head because the volume of water increase as pumping head decreases.

6.1.3. Selection of A pump

For proper selection of pump, it is necessary, to brave certain essential data on the pump installation. The information should include: -

- Number of pump units required
- Nature of liquid to be pumped
- Capacity of pump
- Suction conditions
- Discharge conditions
- Total head
- Position of pump (i.e. horizontal or vertical)
- Intermittent or continuous service

Location geographical, in door, outdoor elevation etc.

After having the idea of essential data on the pump installation, the following points may be kept in mind while selecting any pumping machinery for water works.

1. Reliability of service: - It should be variable and should not fail suddenly and cause trouble.
2. Capacity: - It should be capable of pumping required quantity of water
3. Cost: - It should be cheap in initial cost
4. Power: - The power which is used for running pumps should be available easily at low cost.
5. Maintenance: - The maintenance cost of running pumps should be as less as possible.
6. Efficiency: - Pump should have higher efficiency
7. Deprecation: - pump should have long life and depreciation cost should be less.
8. Cost of labor: - It should be less.

Having motioned the above points in selecting pump type, appropriate type has to be selected for our project variable displacement specifically centrifugal pump is selected.

6.2. Centrifugal pumps

Centrifugal pumps are the most important types of variable displacement pump because of their wide use. It is capable of delivering large quantities of water, against high as well as low head condition, with good efficiency, combining those features with its other attributes such as simplicity, completeness, and adaptability to different methods of driving initiated us to select this type of pump.

The two most commonly used types of centrifugal pumps are: -

1. Vertical spindle pump
2. Submersible pump

1. Vertical spindle pump: - It is frequently used for pumping water form a well. The driving motor is at the surface and the pump is immersed in water and it must, therefore, driven by a vertical spindle. This spindle rotates with in tube or sleeve which is held centrally in the raising main by spindle bearing the pumped water is delivered to surface via the annular space between the sleeve and the raising main.
2. Submersible pump:- It is the modification on the deep well pump as the name indicates in this, electric motor and pump both are submersed in the water. By

Submersing electric motor large economy can be made by avoiding long shaft, large number of bearing and large size rising main etc.

6.2.1. Comparison between Vertical spindle pump and submersible pump

1. Power consumption

a. vertical spindle pump

Due to friction of the rotating parts, it causes high power loss

b. Submersible pump

It uses electrical cable for power supply, hence no power loss due to shaft friction.

2. Service life: -

a. Vertical spindle pump

These are low speed machine usually 1400rpm consequently subjected to less wear & hence last longer:

b. Submersible pump

Due to its high - speed machine it has shorter life

3. Capital and maintenance cost

a. vertical spindle pump

They are expansive in the first cost and take a considerable time and skill to dismantle or erect when repair is necessary.

b. Submersible pump

Quickly and easily installed and they can be of smaller diameter and hence these pumps are less costly and less efficient than vertical spindle pumps.

4. Security

a. Vertical spindle pump

- Pump motors and their parts are exposed to the surface so they may be taken by thieves.

b. Submersible pumps: -

- These pumps have the motor and low assembly as a unit submerged below the lowest pumping water level.

- The water proof cable supplies to the motor

Considering the above comparison criteria and special merits of submersible pump over vertical spindle pump despite its less efficiency for deep tube wells, submersible pump is selected to our water supply project well site.

6.2.2. Position of pumping station and service Reservoir

The position of pumping station and service reservoir is very important for our design system to distribute water economically to the consumers. These positions are determined by observing the top map of the place and other geographical arrangement.

But for our case the two positions are taken from feasibility study due to lake of important materials like the top map of the town. And their positions are such a way that the distribution system has to be supplied by gravity system.

6.3. Economical pumping Mains Diameter

For pumping a particular fixed discharge of water, it can be pumped through bigger diameter pipe at low velocity or through lesser diameter pipe at very high velocity. But, if the diameter of the pipe is increased, it will lead to the higher cost of the pie line. On the other hand, if the diameter of the pipe is reduced, the increased velocity will lead to higher frictional head loss and will require more horse - power for the required pumping, thereby increasing the cost of pumping.

For obtaining the optimum conditions, it is at most necessary to design the diameter of the pumping main, which will be overall most economical in initial cost as well as maintenance cost for pumping the required quantity of water.

The following formula given by Lea is commonly used in determining the diameter of the pumping mains.

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And this formula the Design velocity in the transmission and or gravity pipelines will be with minimum velocity of 0.6 m/s and maximum velocity of 2.0 m/s for economical operation of the system.

(Source Water supply and sanitary Eng'g By. G.S. Birtie)

6.3.1. Calculation of Economical Diameter

Using the formula given previously

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Check for velocity: -

A = area of pumping in m2

Therefore, the velocity is OK since it is with in the allowable limit i.e. 0.6 to 2.0m/s

the selected well site is at an elevation of 564 m a.s.l. Form this elevation the water has to be pumped to a collection chamber which is located at an elevation of m a.s.l. through pumping mains of diameter 100mm.And from this collection chamber water has to be pumped to the service reservoir which is located at an elevation of 188m a.s.l. through another pipe. The diameter of this pipe is calculated as follows: -

Abbildung in dieser Leseprobe nicht enthalten

6.4. Pumping power

Pumps can operate by prime movers which use steam power, gasoline power, diesel power or electrical power. The various types of engines used to operate pumps may be: -

- Diesel Engines
- Steam Engines
- Electrical motors
- Gasoline engines

Since hydroelectric power is cheaper as compared to other power sources, our pumping system will be operated by it. Diesel engines have to be provided to cope with electric power failure.

6.4.1. Pumping power calculation

To calculate or design the pumping power we have to first know the total head i.e. losses and elevation differences between the places for both phases.

Sample calculation

Where, f = friction loss Factor

Abbildung in dieser Leseprobe nicht enthalten

Total Dynamic head from bore hole to pumping station is

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Power calculation

From well site to P.S (pump station)

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CHAPTER SEVEN

SERVICE RESERVOIR

7.1. General

Service reservoir requires storing the treated water for supplying water to the users. The reservoir balances the hourly fluctuation in the water demand. To store and supply purified water and to treat the residual effluents, well build structures are required. It is important to restrain cracking so that cracking will be minimum (or do not take place). The design is generally governed by the requirements of the serviceability . Service state, but stability considerations are important and design must take careful account of the construction methods to be used.

7.2.Service Reservoir Necessity

Water is stored for several purposes and the following functions are fulfilled by storage or service reservoirs.

- To equalize supply and demand oven a long period of high supply.
- To furnish water for such emergencies as firefighting or accidental break down.
- It reduces the size of purification facilities and the number of wells required.
- It reduces the necessary capacity of high rate pumping equipment's.
- It reduces the site of the transmission mains.
- It makes uniform pumping rate possible.
- It reduces friction head losses
- It provides uniform water pressure
- It reduces operating cost by operating pumps at the rate for maximum efficiency.
- Water already pumped it to the elevated tank is more certain of availability that water at the lower level.

7.3. Design capacity and location

Reservoir capacity is determined on the following basis

1. Balancing storage: - is required to equalize between the fluctuations of demand rate with constant rate of pumping.
2. Fire reserve - is the storage required for fighting a fire out break for warder town, the fire demand is considered as 10% of the reservoir capacity.
3. Break dawn storage: - This is the amount of storage down during the failure of power supply or break down of pumps. The period against which it is stored is difficult to ascertain and storing cannot be done for a long period, as that will make the reservoir capacity uneconomically large.

7.4. Reservoir type

The operational processes within the water and other industries dealing with fluids often require circular structures to ensure their systems of work carried out efficiently and economically. Hence circular tank is chosen for the design of warder town water supply.

The primary stresses setup with in the structure are usually a result of the ring tension generated by the contained liquid and the main reinforcement, therefore, consists of bond of circular steel hoops. The ability of the cylinder to increase in diameter is resisted; however, at the base cohere restraints occur. I f out ward movement is prevented by a fixed jointed the ring tension well be zero and vertical bending movement and sheared force will occur. If out ward movement is prevented by a fixed joint the ring tension will be zero and vertical bending movement and shear force will have occurred.

Out of three types of base conditions, i.e. free sliding, pined and fixed base, fixed base is the most effective due to the above reasons i.e. the ring tension will be zero and only vertical bending moment and shear force will occur. Therefore, due to its effectiveness, fixed base type is selected for the design of the circular reservoir.

7.5. Accessories of Service Reservoirs

The service reservoirs are to be provided with the following accessories.

1. Storage tank: - is the most important component. The site and shape of which depend on the design requirements.
2. In let pipe: - for enter of water
3. Man holes: - for providing entry to the inside of reservoir for inspection and cleaning.
4. Out let Pipe: - for the exit of water above full supply level
5. Wash out pipe: - (Drain off pipe) - for removing water after cleaning of the reservoir. This is fitted at the lowest possible water level in the reservoir.
6. Float Games: - This is a float arrangement fitted with a graduated scale, which indicates the water level in the tank at any time.
7. Over flow pipe: - For some reason or other if the water raises above the full designed level of the tank it goes out of the tank through the over flow pipe.
8. Ladders: - They give facilities of climbing the top of the reservoir form tank roof.
9. Ventilators: - This will allow fresh air to enter the reservoir which helps keeping the stored water under better condition.

7.6. Depth and shape

1. Depth

There is an economical depth of service reservoir for any given site. For a given quantity of water either a shallow reservoir having long wells and a large floor area may be constructed. A deep reservoir may be constructed with high retaining walls and a smaller floor area.

Depths most usually used are as follows.

Abbildung in dieser Leseprobe nicht enthalten

2. Shape

Circular reservoir is geometrically the most economical shape giving the least amount of walling for a given volume and depth.

7.7. Reservoir Capacity Determination

The capacity can be analytically determined by finding out maximum cumulative surplus during the stage when pumping rate is higher than water consumption rate and adding to this maximum cumulative deficit which occurs during the period when the pumping rate is lower than the demand rate of water.

The service reservoirs are also modeled to verify continuous balancing capacity of demand and supply without stopping of pumps. From the result it has been proved that the proposed reservoirs can sufficiently satisfy all hydraulic and operational requirements including a reserve for fire and emergency provisions.

The new proposed reservoir will be circular with flat roof and will be made of concrete. The reservoirs will be provided with a valve chamber for both inlet and outlet valve requirements. The reservoir size for the design period of phase I and phase II.

Demand of water always keeps on varying hour, but treated water continuous to come out of treatment plant of a constant rate. Balancing reserve is that quantity of water required storing for balancing the variable demand in the distribution system.

Reservoir capacity is determined on the following basis:

Computation of storage capacity of a reservoir can be obtained from one of the following methods.

a. Analytical method
b. Mass curve technique

Mass curve and analytical method are adopted for the case warder town water supply system.

The analysis of storage capacity can be calculated as follows

i. PHASE I (2011- 2021)

a)By Analytical method

- Total demand of the town = 4492.81m3/day
- Total demand of the town in liters per day = 4492813 lit/day
- Hourly demand of the town =4492.81/24= 187.20 m3/hr.

Table 25 Reservoir capacity computation for phase I

Abbildung in dieser Leseprobe nicht enthalten

Thus the reservoir capacity for phase I from the above table will be

Abbildung in dieser Leseprobe nicht enthalten

Figure 6 graph of mass curve for phase I

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Table 26.Reservoir capacity computation for phase II

Abbildung in dieser Leseprobe nicht enthalten

Thus the reservoir capacity for phase I from the above table will be

A. Volume calculation

Abbildung in dieser Leseprobe nicht enthalten

CHAPTER EIGHT

DISTRIBIUTION SYSTEM

8.1. General

The system of distribution water to consumers is called distribution system. The main objectives of a distribution system are:

- To convey the treated water to the consumers with the same degree of purity.
- To deliver sufficient quantity of water for domestic, industrial and for emergency cases like firefighting.
- To deliver water to the consumers with the required rate of flow & pressure head.

A good distribution system is one which fulfills the above criteria and which is also economical easy to maintain & operate and water tight to the allowable extent.

There are various types of distribution system depending up on the method of distribution. The adoption of one system or the other depends up on the relative elevation of the principal elements of the scheme & the topography of the city.
1. Gravity system: - This is the most reliable method of distributing water when there is some ground level sufficiently above the distribution system (city). The adequate pressure of distribution is maintained by gravity force only. The reliability of this system depends up on the size & vulnerability to accident of the main conduit joining the source & the city.
2. Pumping system: - In this system the distribution pressure is maintained by direct pumping to the mains. This system has an increased maintenance cost for the pumps have to work at varying rates, their life is also reduced. Stand-by diesel pumps are also required in this system to cope with power failure. These stand-by units can also be used for meeting fire demand.
3. Combined gravity and pumping system: - this method is the combination of the above two. In this system the pump is connected to the mains as well as to an elevated

Reservoir. When the demand increases it is satisfied by flow from the pump and the reservoir. Since this system requires uniform rate of pumping and also meets the varying demand it is economical and reliable. The balance reserve in the reservoir serves for both requirements of demand during pump break down and firefighting.

O For warder town the adopted system is combined gravity and pumping system.

8.2. Lay out of Distribution system

There are mainly four types of systems adapted for the layout of pipelines to distribute water.

1. Dead end or tree system: - In this system a main starting from the reservoir is laid along the main road and sub mains are taken off from it along roads joining the main road. Branches and distributors are taken off from the sub main along streets and lanes joining the road service connections are made from these branches.

This system is suitable for towns develops in irregular manner and has the advantages of cheap initial cost, simple design calculation and easy extension of the system when desired. The main disadvantages of this system are: the supply will be cut off if repair work is carried on the main or sub mains, there are dead ends which may contaminate the supply and it is difficult to meet the fire demand during repair.

2) Grid iron system: - In this system the lay out of pipe lines assume the shape of a network and all the dead ends are eliminated by inter connection. The main is laid along the main road and the sub mains are taken off from it in both directions along other roads & streets. Branches are taken off from the sub mains and are inter connected This system is most suitable for towns that have a rectangular lag out of roads & for newly developed cities. The main advantages of this system are all dead ends are eliminated; very small area will be affected during repair work, the friction losses and the sizes of pipes are reduced, and in case of fire demand more quantity of water can be diverted to the affected area by closing the valves of near by localities.

The main disadvantages of this system are increased in the over all cost, difficult design calculation & increased in the over all cost, difficult design calculation & increase in the number of valves to be closed for repair work.

3) Ring or circular system: - In this system the supply main is laid around the distribution district (town). The town is divided in to a number of square districts and around each district sub-mains are laid. The branches are taken from the sub-main and are interconnected.

This system is used only in well planned cities. It's main advantage is that water can reach the consumer very quickly.

4) Radial system: - This is the reverse of ring system. The distribution district is divided into different zones, and a distribution reservoir is placed at the center of each zone. Supply pipes are laid radially and away towards the boundary from the reservoir. This system is suited for

towns which has radial lay out of roads and has the advantage of quick and satisfactory service & easy computation of pipe diameters. After considering the lay out of warder town and comparing the above advantages the Grid iron system is adopted for the lay out of pipes.

8.3. Design procedure of the distribution system

The first step in designing a distribution system is preparing the lay out of the distribution pipes with valves, fire hydrants etc. marked on it.

- Then the total population to be served at each mode is also marked on the plan. Having completed the above the minimum pressure head required at the tail end and near the highest building of the city are also determined and noted on the plan. Finally the main work is to determine the sizes of the distribution pipes, which could carry the required quantity of water at the desired pressure.
- The reduced levels of the town at various points are also marked on the plan.

8.4. Selection of pipe material

Pipes are made from different materials like cast iron, wrought iron, asbestos, steel, plastic etc. so that the material should be selected keeping in mind the following points

- strength, durability & life of pipe
- carrying capacity of the pipe
- Type of water to be converged & its possible corrosive effect on the pipe
- Ease of transportation, handling & installation
- Tightness of joints & ease to tap for making connections
- Maintenance cost, repair etc

The pipe material which fulfills the above criteria and also gives less cost will be selected because it will be most economical.

For Warder water supply project PVC pipes are selected for the distribution system. These pipes have the advantages of low cost, light weight, easy joining & installation etc. CI pipes are used from the borehole to the service reservoir due to its strength, resistance to corrosion & low cost.

8.5. Design of pipe lines

Till date there are no direct methods available for the design of distribution pipes. While doing the design, first of all the diameters of the pipes are assumed, the terminal pressure heads which could be made available at the end of each pipe line after allowing for the loss of pressure head in the pipe link when full peak flow discharge is flowing are then determined. The determination of the friction losses in each pipe line is done. The total discharge flowing through the main pipes is to be determined in advance.

The following points are to be considered wile designing the pipe lines:

The water demand at various points in the city

The velocity of flow in the pipes should be kept between 0.6 m to 2 m

The mains should be designed to carry 3 times the average demand of the city.

The service pipes should be able to carry twice the average demand.

The minimum size of distribution pipe is 40mm and service pipe of 20mm is used for giving house connections.

8.6. Pressure in the distribution system

Due to friction in pipes, the water head is continuously lost as the water enters the distribution main. Head loss occurs at entrance of reducers, valves, bends, and meters etc. till the water reaches the consumers tap.

The effective head available at the service connection to a building is very important, because the height up to which the water can rise in the building will depend up on it only. If adequate head is not available at the connection to the building the water will not reach the upper storage. To overcome this difficulty, the required effective head is maintained in the street pipes.

Since water has to reach each and every consumer it should reach the upper most storage in the city. The following factors determine the required pressure which has to be maintained in the system:

- The height of the highest building up to which water should reach with out boosting.
- The distance of the town from the distribution reservoir.
- The supply is to be metered or not. Higher pressure will be required to compensate for the high

loss of head in meters.

- How much pressure will be required for fire hydrants?
- The availability of funds.

8.7. Nodal Demand computation

The nodal demand of the town was calculated based on land use. In this method the town was divided according to land use and using average day demand a demand to area ratio is calculated for the three types of land use i.e. domestic, public and industrial.

The nodal demand of each junction is then calculated by multiplying the corresponding demand area ratio with the area the node is supposed to serve.

8.8. Appurtenances

Appurtenances are different devices used for controlling the flow of water, for preventing leakage and other similar purposes in the distribution system. The following appurtenances are used for this distribution system:

i) Pipe fittings: - different types of pipe fittings like tees, elbows, caps, ripples, plugs, flanges etc. are to be used during the laying of the distribution system.
ii) Valves: - these are used to regulate pressure, prevent flow of water in the desired direction, release and admit air, control flow of water etc. in the distribution system. Various types of valves like pressure valves, air relief valves, check valves & gate valves are to be used in the distribution system when the condition necessitates their use.

CHAPTER NINE

ENVIRONMENTAL AND SOCIAL IMPACT ASSESSMENT (ESIA)

9.1. Introduction

Environmental and social impact assessment has been one of the most effective measures and nowadays all countries in the world have introduced environmental and social impact assessment (ESIA) requirements and regulations into their development activity. Historically, the role of development projects was aimed at removing strategic economic bottlenecks such as lack of basic infrastructure and creating the basis for economic growth. As a result in most of the developing countries the environment has not featured on the development agenda in the past, since the project evaluation and decision-making mechanisms have focused on short-term technical feasibility and economic benefits. Past development practices have not anticipated, eliminated or mitigated potential environmental problems early in the planning process. This has resulted in a situation where countries experienced a seriously degraded natural environment. Further development also has the potential to further damage fragile environmental systems. With time and as often associated negative environmental and social impacts became better understood, measures are formulated and implemented to identify and mitigate them. In Ethiopia as well the need for integration of environmental concerns into development activities has been accepted. Accordingly, environmental assessment has been recognized as effective tools for facilitating the inclusion of the principles of sustainable development into development proposals. Water supply and sanitation projects are among those development interventions that should have to be subjected to environmental and social impact assessment. With this understanding and conviction. Somali Regional State Water resource Bureau and the National One WASH Program has devoted to solve the critical water problems of Warder town and has made consultancy agreement with ABEBAW DAGNE WATER WORKS CONSULTANT consultants to carry out the detail expansion and rehabilitation designs of water supply and sanitation systems of the Warder town.

9.2. Objectives the ESIA Study

9.2.1. General Objective

The general objectives of the environmental and social impact assessment of the proposed water supply and sanitation rehabilitation and development project is to assess and clearly identify the potential negative and positive impacts of the project and to propose mitigation measures to reduce or avoid the adverse impacts while enhancing the advanced ones and integrate them into the project activities.

9.2.2. Specific Objectives

The specific objectives of the ESIA are to:

- Present baseline data on the existing physical, biological and socio-cultural environment of the project area;
- screen the benefits and adverse effects of the proposed subproject on the biological, physical and socio-economic environment;
- Identify different stakeholders, their involvements and concerns on the proposed project;
- Propose mitigation measures to reduce the adverse impacts while optimizing the positive once associated with the implementation of the proposed subproject.

9.3. Environmental Considerations for Development Projects in Urban Areas

Urban areas (cities and towns) play a key role in the development process of any country. They are, in general, productive places that make more than a proportionate contribution to national economic growth. However, the very process of urban growth often brings with it deterioration in surrounding environmental conditions. As a locus for population growth, commercial and industrial activity, cities concentrate energy and resource use and waste generation to the point that both man-made and natural systems are overloaded and the capacities to manage these systems are overwhelmed. This situation is exacerbated with rapid urban population growth. The resulting environmental damages or costs threaten the continued productivity of cities and the health and quality of life of its citizens. Urban systems and services like water supply, sanitation, etc. are increasingly congested due to population, commercial and industrial growth coupled with poor urban management. Natural resources (water, air, forests, minerals, land) vital to the cities' economic development and to future generations are lost or misused through inappropriate urban policies and lack of environmental awareness. The radius of impact of cities on resources lying far beyond their boundaries is steadily increasing. Furthermore, urban areas are inundated interior waste and choked on their own emissions as a result of inadequate pollution control and waste management practices. As a result many negative impacts are associated with these conditions. The greatest health risks in many urban areas of developing countries including ours are linked to the traditional problems of excreta & solid waste disposal and lack of important services like water supply and proper housing among others. The impacts of greatest concern are still often found at the household and community scale, and are related to deficiencies in urban infrastructure and services. Urban growth has its own environmental impacts including pollution from the waste, household and industrial air pollution, water resources degradation both in quality and quantity, land and ecosystem degradation and loss of cultural property. This shows that urban areas as it is internationally accepted, they have become major "environmental hotspots" that require special attention in project environmental assessments and in environmental planning and management. Therefore any development intervention in the urban areas should have to be seen from all aspects of the environment to make the development sustainable and improve the quality of life.

9.4. The Scope of the Environmental Study

This environmental study covers the impact of the activities that will be accomplished during the construction and operation phases of the Warder town sanitation project with the aim of improving the sanitation and health of the community through the implementation of properly designed appropriate sanitation facilities, with special emphasis on sewerage system, low cost sanitation facilities, storm water drainage system and solid waste management for Warder Town.

9.5. Methodology of ESIA

The ESIA study methodology followed the standard EISA guideline set by Environmental Protection Land Administration and Use Authority (EPLAUA). Data collection both from primary and secondary sources have been conducted to get the overview of the existing situation. This is followed by analyses and identification of problem areas, prediction and evaluation of impacts of the proposed development project, suggestion possible mitigation measures for adverse impacts, and preparation of environmental monitoring and management plan. For the impact evaluation the matrix method with numerical ranking is used for quantitative ranking of the predicted impacts. Methods or approaches were used by the consultants in formulating this report are the following:

- Preparation of checklists and/or questionnaires as appropriate to facilitate data collection.
- Review of pertinent legislations and previous similar studies, and reconnaissance field visit in the project area.
- Conducting field visits to project areas to make physical observation and have an overview of the sites
- Consultation with the community, representatives of local communities' administration and all stakeholders to ensure that relevant issues are identified and their opinions and views to those uses and to the proposed subproject are obtained.
- Analysis of the collected data and information to assess and predict the potential impacts of the proposed project as it is designed.
- Developing feasible mitigation measures that would help to eliminate and/or minimize and compensate for the diverse impacts.
- Formulating a monitoring program to ensure the proper implementation of the recommended mitigation measure and their effectiveness as well as to detect any unforeseen impacts.

9.6. Description of the Existing Environment of Warder Town

9.6.1. Physical Environment of Warder town

9.6.1.1. General

Warder is one of the towns in the country, which faces serious problem regarding water supply and sanitation services. Currently the town does not have safe water supply system at all. Most of the physical environment of Warder town including: Location; Topography & Climate & physiography, Drainage, etc. are also discussed in the previous chapters of this report.

9.6.1.2. Socio-Economic Environment

The Socio economic environment of Warder including: population, health, education trade and Industry are also discussed in the previous chapters of this report.

9.7. Policy, Legal, Institutional and Administrative Frameworks

9.7.1. NATIONAL Policies and Strategies

9.7.1.1. The Constitution of FDRE

As the supreme law of Ethiopia, all national policies, laws and regulations as well as the institutional frameworks of the country must comply with the constitutional provisions. The constitution of the Federal Democratic Republic of Ethiopia, Proclamation No. 1/1995, contains a number of articles, which are relevant to environmental matters in connection with development projects, as well as to the environment in general. Article 43 gives the right to people to improved living standards and to sustainable development. Article 44 provides that all persons have the right to live in a clean and healthy environment. And states in its sub article 1 that: “All persons have the right to live in a clean and healthy environment Furthermore, concerning compensation to project affected people (PAPs), sub article 2 provides that: “All persons who have been adversely affected or whose rights have been adversely affected as a result of state programs have the right to commensurate monetary or alternative means of compensation, including relocation with adequate state assistance”. Article 40.3 of the constitution provides for the public ownership of both rural and urban land as well as all natural resources. It further states that land is the common property of Ethiopian people and cannot be subject to sale or to other means of exchange. Article 40.7 of the constitution states that “every Ethiopian shall have full right to the immovable property he builds and to the permanent improvements he brings about on the land by his labor or capital”. It further states, among other things, that the owner of such rights is entitled to compensation and that the particulars shall be determined by law. Article 40.8 in turn strengthens this by providing for expropriation of private property by the Government for public purposes subject to the payment in advance of compensation commensurate to the value of the expropriated property. The right of the public and the community to full consultations and participation as well as to the expression of their views in the planning and implementation of Environmental Policies and development projects that affect them is enshrined in the constitution (Article 92.3 and 43.2). Women have the right to full consultations in the formulation of national development policies designing and execution of projects, particularly in the case of projects affecting the interests of women. In general, the Constitution is the primary regulation on which the other proclamations and regulations have been based.

9.7.1.2. Conservation Strategy of Ethiopia (CSE)

Since the early 1990s, the Federal Government has undertaken a number of initiatives to develop regional, national and sectoral strategies for environmental conservation and protection. Paramount amongst these was CSE, approved by the Council of Ministers, which provided a strategic framework for integrating environmental planning into new and existing policies, programs and projects. The CSE provides a comprehensive and rational approach to environmental management in a very broad sense, covering national and regional strategies, sectorial and cross sectorial strategy, action plans and programs, as well as providing the basis for development of appropriate institutional and legal frame works for implementation. Based on CSE, the SOMALI Regional State have already developed Conservation Strategy document for its respective Zones and Woredas. The document gives details about environmental issues prevalent in the territory and outlining how the environmental issues to be addressed.

9.7.1.3. Environmental Policy of Ethiopia (EPE)

The Environmental Policy (EPE) of the Federal Democratic Republic of Ethiopia was approved by the Council of Ministers in April 1997 (EPA/MEDAC 1997). It is based on the CSE, which was developed through a consultation process over the period 1989-1995. The policy has the broad aim of rectifying previous policy failures and deficiencies, which in the past have led to serious environmental degradation. It is fully integrated and compatible with the overall long term economic development strategy of the country, known as Agricultural Development Led Industrialization (ADLI), and other key national policies like the National Population Policy and the National Policy on Women. EPE's overall policy goals may be summarized in terms of the improvement and enhancement of the health and quality of life of all Ethiopian's and the promotion of sustainable social and economic development through the adoption of sound environmental management principles. Specific policy objectives and key guiding principles are set out clearly in the EPE, and expand on various aspects of the overall goal. The policy contains sectoral and cross- sectoral policies and also has provisions required for the appropriate implementation of the policy itself.

9.7.1.4. Policies on Land Tenure, Expropriation and Compensation

The constitution of the FDRE states that the right to ownership of rural and urban land, as well as all natural resources. Land is the property of the state/public and does not require compensation. The Constitution gives every person the ownership right for the property he has invested on the land, and in this regard article 40 (7) states that every Ethiopian shall have the full right to the immovable property he builds and to the permanent improvements he brings about on the land by his labor or capital. If the land that is owned by an individual is expropriated by the Government for public use, the person is entitled for compensation. In this regard, article 44 (2) of the Constitution states that all persons who have been displaced or whose livelihoods have been adversely affected as a result of state programs have the right to commensurate monetary or alternative means of compensation, including relocation with adequate state assistance.

9.7.1.5. Water Supply and Sanitation Policy

The water supply and sanitation policy of the federal government has identified the type of water supply to include the supply for human as well as animal consumption industrial and other uses outside irrigation and hydropower. The human water supply as per the policy document is meant rapid socio economic development through better health care and productivity of the Ethiopian peoples. Thus, as stated in the policy document, the overall objective of water supply and sanitation policy is to enhance the well-being and productivity of the Ethiopian people through provision of adequate, reliable and clean water supply and sanitation services and to foster its tangible contribution to the economy by providing water supply services that meet the livestock, industry and other water users' demands. The General Policies of water supply include the following:

- Recognize that water supply is an integral part of the overall water resources management and incorporate water supply planning in the domain of comprehensive water resources management undertakings.
- Promote the development of water supply on participation driven and responsive approaches without compromising social-equity norms.
- Integrate and co-ordinate the development of water supply with other sector development objectives including irrigation, hydro-power.. .etc.
- Create and promote a sense of awareness in communities of the ownership and their responsibilities for operation and maintenance of water supply systems and develop participatory management practices.
- Enhance the development of different indigenous water sources being used by communities to improve rural water supply.
- Ensure that rural drinking water and livestock water supply undertakings shall be integral part of the overall socio-economic development, centered on self-reliance, community participation and management

In relation to water supply tariffs the policy document use to describe the following major points that should be considered during the project design and tariff setting

1. Ensure that Tariff structures are site-specific and determined according to local circumstances,
2. Insure that rural tariff settings are based on the objective of recovering operation and maintenance costs while urban tariff structures are based on the basis of full cost recovery.
3. Ensure that tariff structures in water supply systems are based on equitable and practical guidelines and criteria.
4. Establish a "Social Tariff that enables poor communities to cover operation and maintenance costs.
5. Establish progressive tariff rates, in urban water supplies, tied to consumption rates.
6. Develop flat rate tariffs for communal services like hand pumps and public stand posts.

Regarding the enabling environment the policy document provides the following Institutions and Stakeholders involvements for water supply schemes

1. Ensure that the management of water supply systems to be at the lowest and most efficient level of institutional set up, which provides for the full participation of users and to promote effective decision making at the lowest practical level.
2. Develop coherent and streamlined institutional frameworks for the management of water supply at the Federal, Regional, Zonal, Woreda and Kebele levels and clearly define the relationships and interactions among them.
3. Develop coherent and appropriate guidelines, standards, principles and norms for streamlining the intervention of ESAs, NGOs loans, grants and other donations.
4. Develop a framework for the sustainable and effective collaboration amongst all stakeholders including the public sector, donors, communities and the private sector at all levels as well as creates and legalize forum for the participation of all stakeholders.
5. Define and implement the respective roles of the various institutions and stakeholders at all levels including Federal, Regional governments, ESAs, NGOs, private sector, etc.

9.7.1.6. Ethiopian Water Resources Management Proclamation, No 197/2000

Ethiopian Water Resources Management Proclamation The proclamation has provide the following article 21 and its sub articles on Water charges

1) Water charge shall be paid to use water resources for any use allowed under this proclamation. The amount of water charge shall be as may be specified in the regulations to be issued for the implementation of the proclamation
2) The supervising body is authorized to collect the water charge determined under sub article (1) of this article
3) The Supervising body may exempt certain persons from the payment of water charge as may be specified in the regulations to be issued for the implementation of this Proclamation

Part eight of the proclamation recognizes the establishment of Association of water users and describes the nature of organization under article 27/1 - 4

1) The Supervising body may. In consultation with the appropriate public bodies, encourage the establishment of water users' associations. As it deems necessary to utilize water for beneficial uses.
2) Without prejudice to the provisions of sub-Article (I) of this Article association of water users may be established upon initiation and the will of the users.
3) Details of the organization of water users' association shall be pursuant to regulations to he issued for the implementation of this Proclamation.
4) The relevant provisions of the Civil Code regarding the formation of such associations shall apply

The project study and design has been done based on these policy provisions and legal frameworks to benefit from all angles.

9.7.1.7. Wildlife Policy

The wildlife policy covers a wide range of policies and strategies relating, amongst others, to wildlife conservation and protected areas. It is developed by Ministry of Agriculture /MoA/ whose prime objective is the preservation, development and sustainable utilization of Ethiopia's wildlife resources for social and economic development and for the integrity of the biosphere.

9.7.1.8. Forest Policy and Strategies

There is no forest policy statement in place at the federal level. However, draft forest development and conservation policy is currently under discussion in the Moa and also at regional levels. They are expected to express the determination and commitment of the government to conserve and develop and rehabilitate the forest resources of the country and regions.

9.7.1.9. National Population Policy

This policy was issued in April 1993 and aims at closing the gap between high population growth and low economic productivity, through a planned reduction in population growth, combined with an increase in economic returns. With specific references to natural resources, the population policy had the following specific objectives:

- Marking population and economic growth compatible and the over exploitation of natural resources unnecessary.
- Ensuring spatially balanced population distribution patterns, with a view to maintaining environmental security and extending the scope of development activities.
- Improving productivity of agriculture and introducing off-farm non-agricultural activities for the purpose of employment diversification.
- Maintaining and improving the carrying capacity of the environment by taking appropriate environmental protection and conservation measures.

9.7.1.10. National Policy on Women

This policy was issued in March 1993 and stresses that all economic and social programs and activities should ensure equal access of men and women to the country's resources and in the decision making process so that they can benefit equally from all activities carried out by the central and regional institutions.

9.7.1.11. National Environmental Impact Assessment /EIA/ Procedural Guidelines

The Federal Environmental Protection Authority /F EPA/, 2003, EIA Guidelines are based on the Constitution, the Environmental Policy of Ethiopia, the Proclamations on EIA, Pollution Control and Establishment of EPA and other Environmental Organs in the country. The document gives detailed required procedures for conducting an EIA in the country and the requirements for environmental management. The FEPA EA Procedural Guideline mainly aims particularly at:

- Ensuring the implementation of the EPE and compliance of EA related legal and technical requirements,
- Providing a consistent and good practice approach to EA administration in Ethiopia,
- Assisting proponents and consultants in carrying out their environmental assessment related tasks,
- Assisting Interested and Affected Parties, especially communities in realizing their environmental rights and roles,
- Assisting Environmental Protection Organs, Competent and Licensing agencies in discharging their roles and responsibilities, and
- Establishing partnership and networking among and between key stakeholders in EA administration.

9.8. Environmental Impacts

9.8.1. General

Development interventions including development of proper water supply system that is expected to have positive and negative impacts at different degree on biophysical and/or socio-economic environment during different stages of development process mainly construction and operation phases

In this regard the potential positive and negative impacts associated with the water supply system development for Warder town are discussed below.

9.8.2. POSITIVE Impacts On the Bio-Physical and Social ENVIRONMENT

The main positive impacts likely to result from implementation of the proposed water supply project include the following:

- Improved scarcity of potable problems and nutritional status through increased and varied home consumption
- Improved economic status and access to health care;
- Gain of time, especially for women and girls that may be used for other, productive activities, and resulting gains in overall economic productivity
- Improved domestic water supply for Better comfort, better lifestyle and hygiene;
- Creation of employment opportunities at both construction and operation phases for more productive labor;
- Reduction in water-borne diseases such as dysentery, cholera and others
- Enhancing Investment - The construction of this project enhances the investment attraction for privet investors.
- Urban development and urbanization process - create the opportunity for urbanization process to the villages found around town and corridor.
- Sustainable development- project will contribute the major role for sustainable development of the nation in general and region in particular.

9.8.3. Detrimental negative impacts on the bio-physical and social environment

- Disturbance to topsoil; created by earthmoving works and heavy vehicle traffic at construction phase
- Impact of ground water; abstraction on ground water table level and its availability to other users
- Impact of ground water; abstraction on potential changes in water salinity where there is a complex balance within the aquifer between fresh water and salty water
- Public Health; Impacts on public health due to increased dust, noise, traffic accidents, and increased wastes, Particularly asbestos/cement pipes; The increased production of drinking water may lead to an increased generation of wastewater and will affect the sanitation
- Impact of the chemicals; contained in the drilling fluids, Spillage of fuel, oil, grease from the garage and pump house of the project may result in the pollution of the nearby and around the borehole site.
- Transmission Pipelines; Potential leaks at operation phase with health risks associated with standing water.

9.8.4. Mitigation measures

Mitigation measures are actions that minimize the negative environmental impacts of a proposed action. Negative impacts are the environmental “Problem” and mitigation is the “solution” in an EIS. It is a difficult to have a solution for all environmental problems however, and mitigation is discussed in by the country as required where “practicable “and where it is feasible.

9.8.5. The CEQ regulations provide the following example of mitigation

- Reduce the impact by not taking a certain action or parts of an action.
- Case the impact by repairing rehabilitating or restoring the affected environment
- Reduce or eradicate the impact over tine by preservation and maintenance operations during the life of the action
- Counterweigh for the impact by replacing or providing substitute resources or environment

Appropriateness, effectiveness, implement, monitoring, enforcement should be considered when identifying and evaluating mitigation measures.

For the negative impacts listed above mitigation measures have to be applied before or during the commencements of the project as much as possible. The corresponding mitigation measures during the construction stage are: -

- To reduce the problem of interruption and decreasing of yields of the existing water supply it is better to lay pipes part by part.
- To prevent the soil erosion due to digging of truncated for pipe laying, disturbed top soil should be pressured and restored with adequate precaution.
- The impact of noise can be limited by imposing maximum noise levels on the contact and by restoration of working hourly particularity with respect to locally recognized days of rest.
- For the traffic obstacle problem, the works should be facilitated as possible.

REFERENCES

- Water Supply Project for Urban Centers (Japan International Cooperation Agency,1997)
- E.W STEEL and TERENCE J. MC GHEE, Water Supply and Sewerage, Fifth Edition. 1984
- G.S. BIRDIE, Water Supply and Sanitary Engineering, 1990.
- Water supply and sanitary Eng'g By. G.S. Birtie
- SAM Y.EDIDIAH. Centrifugal Pump Users Guide Book, Problems and solution, 1996. Dr. P.N.
- MODI, Hydraulics and Fluid Mechanics, March, 1998.
- H.M Rughuntah, Ground Water Hydrology, Ground water Survey, and Pumping Test, Rural
- Water Supply and Irrigation System, 1983.
- D.L. Gupta Bharat Singh, Water Supply and Sanitary Engineering, Jan, 1976.
- 9- G, DRISCOLL, Ground Water and Wells, Second Edition, 1986.

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Details

• Course: thesis for undergraduate
• Grade: A+
• Author: Mahamed Bakar (Author)
• Publication Year: 2019
• Pages: 89
• Catalog Number: V1158444
• ISBN (eBook): 9783346566560
• ISBN (Book): 9783346566577
• Language: English
• Tags: water supply distribution system design ethoipia