Analyzing the Potential of Roof Rainwater Harvesting ... · PDF fileAnalyzing the Potential of...

Analyzing the Potential of Roof Rainwater Harvesting Systems for Water Supply in

Western Mountains in Yemen (Case Study: Manakha Area)

The Study Research Submitted by:

Abdullah Mohammed AL –Saidi1 NWSA Agricultural Eng.

Dr. Sharafaddin A. A. Saleh2Main Supervisor WEC

Dr. Abdul-Rahman Al-Eryani3Co-Supervisor Agri. College SU

Dr. Ahmed M. Alwadei4Co-Supervisor Agri. College SU

Water and Environment Center (WEC)

Sana’a University

Jan 2015

1 MSc Student in WEC & Agri. Eng. NWSA

2Associate Prof. of Civil Engineering and Water Management (WEC)

3Assistant Prof. Agricultural Eng. And Water Management Agri. College SU

4Assistant Prof. Agricultural Eng. And Water Management Agri. College SU

I

TABLE OF CONTENTS

TABLE OF CONTENTS ......................................................................................................... I

LIST OF TABLE .................................................................................................................. III

LIST OF FIGURES .............................................................................................................. IV

ABSTRACT ......................................................................................................................... 3

INTRODUCTION ................................................................................................................ 4

1.1 BACKGROUND ........................................................................................................... 4

1.2 PROBLEM STATEMENT ................................................................................................. 5

1.3 OBJECTIVES OF THE STUDY ............................................................................................ 5

LITERATURE REVIEW ........................................................................................................ 6

2.1 WATER HARVESTING .................................................................................................. 6

2.2 IWRM AND WATER MANAGEMENT THROUGH SUB-SECT ORAL TO CROSS-SECT ORAL: .............. 6

2.2.1 IWRM planning process ................................................................................. 8

2.3 STRATEGIES FOR WATER MANAGEMENT: ......................................................................... 8

2.4 WATER HARVESTING CLASSIFICATION: ........................................................................... 9

2.5 RAINWATER HARVESTING ............................................................................................ 9

2.5.1 Definition ........................................................................................................ 9

2.5.2 Need for rainwater harvesting ..................................................................... 10

2.6 WHAT IS A RAINWATER HARVESTING SYSTEM? ............................................................... 10

2.6.1 Components of rainwater harvesting systems ............................................ 11

2.7 ROOFTOP SYSTEM:.................................................................................................... 11

2.7.1 RRH components .......................................................................................... 12

2.8 SUITABLE COMPONENTS OF RRH SYSTEMS: ................................................................... 12

2.9 DEVICES & TECHNIQUES FOR BETTER WATER QUALITY: ................................................... 14

METHODOLOGY.............................................................................................................. 18

3.1 RESEARCH METHODOLOGY: ....................................................................................... 18

3.2 FIELD WORK DESCRIPTION AND DATA COLLECTION ........................................................... 19

3.3 STUDY AREA ............................................................................................................ 20

II

3.3.1LOCATION .............................................................................................................. 20

3.3.2 POPULATION ......................................................................................................... 21

3.3.4 GEOLOGICAL OF THE MANAKHAAREA ......................................................................... 22

3.3.5 CLIMATE – METEOROLOGICAL CONDITIONS ................................................................. 23

RESULTS AND DISCUSSIONS .......................................................................................... 25

4.1 SURVEY RESULT AND ANALYSIS ................................................................................... 25

4.2 HOUSEHOLD SOCIOECONOMIC PROFILE ........................................................................ 25

4.2.1 Household Characteristics ............................................................................ 25

4.2.2 Household Income and Expenditure: ........................................................... 26

4.2.3 Inhabitants Opinion about RRH: .................................................................. 30

4.3 ROOF TOPS AREA ESTIMATION IN MANAKHA CITY: ......................................................... 33

4.4 TANKS SIZES AND TECHNIQUES OF RRH ........................................................................ 34

4.5 TANKS PLACES SELECTION .......................................................................................... 35

CONCLUSIONAND RECOMMENDATION ........................................................................ 37

5.1 CONCLUSION ........................................................................................................... 37

5.2 RECOMMENDATIONS ................................................................................................ 37

REFERENCE ...................................................................................................................... 39

III

LIST OF TABLE

Table ‎3-1 Data collection techniques and tools at the household level. .................................... 19

Table ‎3-2 Data collection techniques and tools for communities and relate authorities .......... 19

Table ‎3-3 Manakha Population up to 2025 ................................................................................. 22

Table ‎3-4 Shows a summary for the metrological data for Manakha area ................................ 23

Table ‎4-1 Household Characteristics ........................................................................................... 25

Table ‎4-2 Means, frequency and time spent fetching water from the source ........................... 29

Table ‎4-3 Appropriate tanks types and cost estimation in Manakha ......................................... 35

IV

LIST OF FIGURES

Figure ‎2-1 Water use sectors ........................................................................................................ 7

Figure ‎2-2 General framework of IWRM ....................................................................................... 7

Figure ‎2-3 Stage in IWRM planning Process and Implementation ............................................... 8

Figure ‎2-4 The Method of Water Harvesting ................................................................................ 9

Figure ‎2-5 Installation Planning for a RWH System .................................................................... 11

Figure ‎2-6 RRH components systems .......................................................................................... 12

Figure ‎2-7 Sample Filtration screen ............................................................................................ 15

Figure ‎2-8 Sample Top tank filter ................................................................................................ 15

Figure ‎2-9 Semi-automatic Method: Simple down pipe first flush device.................................. 16

Figure ‎2-10 Standpipe first-flush device ..................................................................................... 16

Figure ‎2-11 First flush diverters withfloating ball floating ball ................................................... 17

Figure ‎3-1 Manakha location ...................................................................................................... 21

Figure ‎3-2 Geological Map, Manakha Basin ................................................................................ 23

Figure ‎3-3 Annual rainfall Isohyets map for Manakha area ........................................................ 24

Figure ‎4-1 Monthly income of Manakha people ........................................................................ 26

Figure ‎4-2 The main water resources for domestic uses ............................................................ 27

Figure ‎4-3 Water consumption (L / day ) per capital .................................................................. 28

Figure ‎4-4 The price of water unit from public network............................................................. 28

Figure ‎4-5 Inhabitants opinions and willingness to use RRH ...................................................... 31

Figure ‎4-6 People reasons of not encouraging, sharing RRH ..................................................... 31

Figure ‎4-7 Interviewees’ willingness and ability to participate in RRH projects ......................... 32

Figure ‎4-8 Different uses of rainwater when applying RRWH projects ..................................... 33

Figure ‎4-9 Image of Manakha city showing the rooftops areas in yellow .................................. 34

V

LIST OF ABBREVIATIONS

NWSA National Water and Sanitation Authority

RRH Rooftop Rainwater Harvesting

BCM Billion Cubic Meters

MCM Million Cubic Meters

TWRM Integrated Water Resource Management

GWP Global Water Partnership

UNEP United Nations Environment Program

RWH Rainwater Harvesting

NWRA National Water Resources Authority

NGOs Nongovernmental Organization.

M.A.S.L Meter Above Sea Level

DEM Digital Elevation Model

SE South East

NW North West

CAMA Civil Aviation and Meteorology Authority

H/H Household

YR Yemeni Rial

SFD Social Fund for Development

GIS Geographic Information System

JICA Japan International Cooperation Agency

SPSS Statistical program for Social Science

FGD Facility Group Discussions

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ABSTRACT

Yemen is characterized by arid to semi-arid climate which have few rainfall and surface water.

In this kind of climate the rainfall is limited, while the agricultural water demand is very high.

Therefore, Yemen has been categorized as one of those countries that’s suffering from water

scarcity. In Manakha city, the availability of water that is produced by National Water &

Sanitation Authority (NWSA) is estimate to be about 83,757 m3 per year. This water

production gives a daily water delivery only 15.30 L/ per capita/day. While the average Water

consumption is 28-30 L / per capita /day, that mean the water delivery supply only 50% of the

demand.

The main objective of the research is to assess the technical, economic and social feasibility, of

roof top rainwater harvesting systems in Manakha town, in order to contribute to domestic

water needs and reduce the pressure on groundwater resources and household’s financial

resources. The study also deals to achieve a number of other sub-objectives, which are:

evaluating the socio-economic feasibility of applying RRH techniques in the target area;

calculating the total harvestable water volume from the roofs and suggested bonds of

Manakha; identifying the best water harvesting techniques, including the quality and economic

aspects, which could be used for RRH in Manakha. The study conducted a socioeconomic

survey, which objectives are: to assess the existing socioeconomic conditions in the study area;

to identify the types of existing water supply systems and sanitation infrastructures at the

household level; and to assess people’s willingness and ability to pay for the improvement and

construction of rooftops rainwater harvesting systems. In addition to the field and

stakeholders’ surveys, the study used other materials and methods including data collection;

questionnaire; water measurements; and data analysis using the Statistical Package for Social

Science (SPSS) program.

In this study the surface area as well as the rooftops in the Manakha have been estimated; the

calculations are about 0.138km2 and 138189.65m2 respectively. Adding to that, the potential

quantity of rainwater, which can be harvested from the roofs of Manakha city buildings have

been calculated based on the digitizing 2014 satellite image. The results show that annually

31092.67 Cubic Meters can be harvested from rooftops of the city buildings, which represent

about 21 % from the annually water demand of this city. On the other hand, the results of the

social survey indicate that 94% of the household in the study area is willing to cooperate & pay

for RRH.

Finally, a number of recommendations were highlighted by the study including more

awareness and research.


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Chapter One

INTRODUCTION

1.1 Background

Water is the important source for life and development. The water scarcity and

its quality deterioration have become one of the biggest challenges all over the world.

The water scarcity is more acute in the western part of the country where 90% of the

population is concentrated. Also, major cities are located in this part catchments with

limited local water resources.

Yemen is characterized as arid to semi-arid climate with few rainfall and very

rare surface water is available. The rainfall is limited while the agricultural water

demand is very high. Therefore Yemen has been categorized as one of those countries

that’s suffering from water scarcity.

Yemen became one of the only four countries in the world designated as

absolutely water shortage, with annual water availability per capita is around 2 %of

the other countries. Where the annual water availability per capita is only 120 m3,

while in the other countries in the world the average annual water is 7,500 m3 per

capita. Also, the annual water is represent only 14 % compared to the average of 850

m3 per capita for the Middle East and North Africa countries.

The water studies revealed that, the total annual national renewable water

resources in Yemen are2.5 BCM, while annual abstraction is 3.4 BCM. This means that

0.9 BCM (36%) of groundwater is depleted annually (JICA, 2007).

In Manakha city, the availability of water which is produced by NWSA is about

83,757 m3 per year, which gives a daily water delivery only 15.30 L/ per capita/day.

While the annual water availability per capita is only 120 m3 in Yemen (NWSA, 2010).

Due to the failure shortage of the public system supply, people also fetch about water

from other resources, such as water which is delivered by water tankers. However, in

this area is still enormous water shortage, and high water prices, that is pressing on

household’s economics.


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1.2 Problem Statement

In summary, the problems that lead to water shortage in Manakha area are:

Limited water resources availability, inducing physical and economical water

scarcity.

Manakha town served by only one source (NWSA), which is operated boreholes

from volcanic rocks aquifer with declining yield and high water production

costs. That mean a little water is supplied from the public system and

commercial tankers supply form other resources are common.

The population growth lead to increase water demand.

The expansion of the agricultural areas, which are used the surface irrigation

systems.

Lack of water conservation awareness among societies, and absence of laws

and regulations implementation. Consequently, these reasons have led to the

increase of digging wells which results in an overexploitation of the

groundwater.

Conflicts among the users, degradation of water quality, and increasing costs of

pumping are some results of the increasing pressure on the non-renewable

groundwater resources.

1.3 Objectives of the study

The overall objective:

Assess the technical, economical and social feasibility, of roof top rainwater harvesting

systems in Manakha town, in order to contribute in domestic water needs and reduce

the pressure on groundwater resources and household’s financial resources.

The specific objectives are:

Evaluate socio economic feasibility of applying RRH techniques in the target

area.

Calculate total harvestable water volume from the roofs and suggested bonds

of Manakha

Identify the best water harvesting techniques, including the quality and

economic aspects, that could be used for RRH in Manakha.

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Chapter Two

Chapter Two LITERATURE REVIEW

2.1 Water Harvesting

Water harvesting is a process of renewable water sources, that is known the

activities of available water resources collection. Temporarily storing excess water for

uses when is required, especially in the periods of drought or when no perennial

resources are available. The starting point is the collection of natural water resources

as rainwater, fog water, runoff water, or even treated wastewater. Finally, the water

harvesting is a technique for collection and storage of rain water, runoff or flood water

that can be used for different purposes as follows (Saleh, 2010):

For storage in (tanks, dams, or containers) or in the soil profile as sand dams.

For irrigation or commercial and industrial purposes.

For groundwater recharge.

Moreover, selecting WH technique depends on many factors include: (Aklan, 2011).

Physical factors such as rainfall intensity, hydrology, topography, and soil

profile characteristics.

Socioeconomic factors such as household income, expenditure, awareness.

Environmental factors such as appropriate places, pollution.

Ecological factors.

The purpose of rainwater use factor, such as domestic use, irrigation uses.

2.2 IWRM and water management through sub-sect oral to cross-sect

oral:

Integrated Water Resource Management( IWRM) is the 'integrating handle'

leading us from sub-sect oral to cross-sect oral water management.


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Figure 2-1 Water use sectors

Source: (GWP, 2010)

IWRM is “a process which promotes the coordinated development and

management of water, land and related resources, in order to maximize the resultant

economic and social welfare in an equitable manner without compromising the

sustainability of vital ecosystems”. Relating Global Water Partnership (GWP) (2010),

IWRM is an appropriate approach to water management. It has been accepted

globally as the way of efficient, equitable and sustainable development and

management of the limited water resources. However, achieving sustainable

development management of the whole water sources including the renewable WH

source required three factors to be taken into consideration as shown in (Figure 2-

2)(GWP, 2010).

Figure 2-2 General framework of IWRM

Source: Global Water Partnership ( 2010 )


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2.2.1 IWRM planning process

According to UNEP guide the IWRM planning process and implementation is the

development objectives of IWRM throughout many process, such as establishing

IWRM goals, building IWRM awareness raising, analyzing IWRM framework gaps,

preparing IWRM strategies and action plans, and building commitment at the highest

political levels as shown in (Figure2-3)

Water harvesting is consideration as part of (IWRM). All users manage water

according to different strategies and principles, depending on the amount of rainfall,

potential evapotranspiration, cropping system and other uses of water. (UNEP, 2010)

Figure 2-3 Stage in IWRM planning Process and Implementation

Source. (UNEP,2010)

2.3 Strategies for water management:

According to water harvesting guidelines to good practice(Liniger &Mekdaschi

Studies, 2013). four strategies can be recognized:

1. Management of excess water from rainfall or seasonal flooding through

controlled drainage and water storage for future uses. Where floodwater

harvesting is the most suitable in humid and sub-humid conditions as well as

semi-arid and arid conditions.


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2. Increasing rainwater capture and water availability, by making use of surface

runoff is suitable for dry sub-humid to arid conditions.

3. Reducing in situ water loss: improving water in filtration and reducing

evaporation; where soil water conservation practices that prevent surface

runoff and keep rainwater in place.

4. Increasing water use efficiency (e.g. good agronomic practice, including use of

best-suited planting material and fertility management). Finally, Water

management is the overarching term that covers all practices improving water

availability.

2.4 Water Harvesting Classification:

The classification of water harvesting based on catchment type and size, and the

method of water storage, as shown in (Figure 2-4)

Figure 2-4 The Method of Water Harvesting

Source: Prinze, 2011.

2.5 Rainwater Harvesting

2.5.1 Definition

Rainwater harvesting is the capture, diversion, and storage of rainwater for a

number of different purposes including landscape irrigation, drinking and domestic

use, and aquifer recharge. (Krishna, 2005).

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2.5.2 Need for rainwater harvesting

Due to the development, population growth, climate change, and the overall

increased demand for water resources, many communities all over the world are

approaching the limits of their traditional water resources. Therefore, they have to

turn to alternative or new and renewable water resources like rainwater harvesting.

The Rain water harvesting (RWH) can be contributed to environmental, social, and

economical benefits, as well as to poverty alleviation and sustainable development.

For instance, Roof Top Rain Water Harvesting (RRH) has a socio-gender positive

impact. When RRH is implemented the women and children can be saved from water

fetching. The availability of water from different natural sources such as lakes, rivers

and shallow groundwater can fluctuate strongly. While collecting and storing rainwater

can provide water for domestic uses in the periods of water shortage. Also, when the

water quality is low in rivers or other surface water resources, the rainwater is good

for uses (Worm and Hattum, 2006).

2.6 What is a rainwater harvesting system?

A rainwater harvesting system is all related components that are used together

to collect, store, and distribute rainwater in house .The installation of RWH system

need to be planed and design to ensure the proper operation of the system. Figure 2-5

shows the installation planning for a RWH system that must be taken into account:


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Figure 2-5 Installation Planning for a RWH System

Source. (TBM, 2010)

2.6.1 Components of rainwater harvesting systems

The three main components of RWH systems according to (Worm and Hattum,

2006, and Patil, 2006) are catchment area, storage reservoir, and delivery system.

Therefore, all rainwater harvesting structures will have these three basic

components which will be clarify in the following:

1. Catchment area is the surface area utilized for capturing the rainwater.

2. Storage reservoir is dams, tanks, and cisterns or percolation pits, sand dams,

and trenches which are used for collecting or holding the water in soil profile.

3. Delivery system is the system of pipes or percolation pits and tranches, where

water is transported from the catchment area to the collection device or from

the collection device to the place of use.

2.7 Rooftop system:

Rooftop rainwater harvesting is the process of collecting rainfall run off from

rooftops into a tank or storage devices for future uses as is needed.


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2.8 RRH components

There are three components of RRH systems: the catchment area, the delivery

system and the storage reservoir (tanks), (as shown in Figure 2-6). In the next section

below, the three main components with other secondary components have been

explained.

Figure 2-6 RRH components systems

Source: (CEHI, 2009)

2.9 Suitable components of RRH systems:

a.Roofs

Roofs are made from a variety materials such as concrete, concrete tiles, metal

sheets, ceramic tiles, rock slate and Ferro cement. All these materials are considered

as suitable materials for RWH from roofs,(Frances Carpenter, 2009).However, probably

the most common roofs in Yemen is concrete, cement mortar and corrugated

galvanized steel sheets roofs,(Saleh, 2010). Where the galvanizing protects the steel

from corroding, and metal sheet roofs are smooth and less retain contamination (e.g.

dust, leaves, and bird-droppings) compared with concrete tile roofs. Although, zinc has

a low toxicity to humans, but that run-off water from the common galvanized steel

roofs should not exceed WHO-permitted zinc levels (Mosley, 2005). Farther, RW

contamination from roofs can be prevented by, (Rain Foundation, 2008):

Using non-toxic materials for roofing, like cement, corrugated and galvanized

iron.


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Avoiding metal roofs.

Cleaning the catchments from birds, and crawling animals waste

Frequently cleaning the catchment surface (from human, animal and organic

matter), removing overhanging branches and fencing of the catchment area in

the case of surface runoff.

b.Gutters:

Gutters are the channels around the edge of the roof to collect and transport

rainwater to the storage tank. Gutter can be made using any of the following

materials: Galvanized iron sheet, Aluminum sheet, PVC material, Bamboo and not –

toxic materials. The connection of gutters and down spouts should be done very

carefully to avoid any leakage of water and to maximize the yield. Gutter screen may

be required at the end of gutter (entrance of water) to prevent leaf and other large

materials from entering pipe and then storage tank, (Pophale, 2006).

c.Tanks:

An appropriate storage tank is needed to hold the water that is collected from

roofs and other surfaces. Several types of storage devices have been used, although a

large tank is usually required for storing sufficient quantities of water for a household.

A small storage tanks include those made of Ferro-cement, plastic, metal and

fiberglass should be appropriated. Ferro cement tanks have been used successfully for

over a century with a well maintained it can provide a good water quality. Plastic tanks

are becoming increasingly used and also provide a good water quality. Farther the

plastic tanks should be constructed from food-grade plastic material in order to

prevent leaching of any potentially harmful compounds into the collected water. While

open tanks are not recommended for collection of rainwater for drinking purposes as

it is exposed to contaminants from leaves and dust, which may easily enter into it. It is

important that the storage tank does not introduce contamination into the water from

the material itself or remnants of substances that have previously been stored in it. For

this reason it is not recommended that old oil or chemical drums to be used for water

storage, because these may contain substances harmful to human health. Moreover,

storage tank materials should prevent or minimize light penetration to reduce algal

growth and other biological activity, which helps in maintaining water quality.

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The tap for the tank should be protected from animals, which may drink from it

or brush against it, leading to subsequent water contamination. The level of the tap in

regard to the base of the tank should not be low that debris from the bottom of the

tanks is drawn up with the out flowing water. Tanks with no tap are not recommended

as water abstraction is typically with a lowered bucket which increases the risk of

contamination. An additional tap can be installed in the base of a tank to be made the

emptying for cleaning easier, (Rain Foundation, 2008, Saleh, 2010); Mosley, 2005).

2.10 Devices & Techniques for Better Water Quality:

a.Filtration Screens:

The quality of stored water can be improved if leaves and other debris are kept

out of the system by using a coarse filter or screen. Without screens present, leaves

and other material may enter tanks and provide food and nutrients for micro-

organisms to survive. In the absence of such nutrients, bacteria eventually (2-20 days)

die off from starvation.

A filter or screen should be easy to clean and replace, and should not block. It is

essential that there are no gaps in the storage tank inlets where mosquitoes can enter

or exit. Stainless steel and synthetic mesh as coarse filtration screens are simple, most

inexpensive and widely used technology. Filtration screen can be installed in the inlets

of gutters (Figure 2-7).

The down-pipe from the roof could enter the tank through tank filter, such as

fine cloth filter, the cloth filter can be tied to the top of a bucket or vessel with bores at

the bottom. The fine filter is filled with gravel and sand, (Figure 2-8) the filter should be

cleaned after every rainfall event. New technologies of the top tank filters made from

either aluminum or plastic container and have the advantage of ease in removing,

cleaning and replacing,(RAINWATERCLUB, (n.y.)) .

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Figure 2-7 Sample Filtration screen

Aluminum mesh filter Cloth filter

Figure 2-8 Sample Top tank filter

Source: Mosley (2005). (Architecture Development, (n.y.))

b.First flush instrument:

Debris, dust, blooms, animal faeces, contaminants and dirt collect on the roof

during non-rainy periods when the first rain arrive. A first flush system arrangement is

made to avoid the entering unwanted material into the Filter media & storage tank.

There are a number of simple systems which are commonly used.


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Figure 2-9 Standpipe first-flush device

Figure 2-10 Semi-automatic Method:

Simple down pipe first flush device

Source: RWH for Army Installations ( 2010 ). Source: Luke Mosley (2005).

Down pipe moved away from tank inlet for first flush. The device fills with

rainwater first, and then allows water to flow through the outlet to the storage

system. This is a simple manually operated arrangement, whereby the down pipe is

manually moved away from the tank inlet and replaced again once the first flush water

has been disposed. (Figure 2-9) shows PVC standpipe one.

Other simple and semi-automatic one (Figure 2-11, 2-12) could be used just by

installing a valve at one end of the downpipe while the other end goes to the storage

tank. However, when the runoff from the roof starts, the first flush valve should be

opened for a while to get rid of accumulated contaminants, then the valve should be

closed allowing the clean rainwater to enter the storage tank. The water containing

contaminants in the first flush tanks can, depending on its quality, be used for other

purposes besides drinking (e.g. cleaning, washing, watering vegetable gardens).


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Source: (Water Harvesting Guidelines to Good Practice, 2013)

Figure 2-11 First flush diverters withfloating ball floating ball


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Chapter Three

Chapter Three METHODOLOGY

3.1 Research Methodology:

To achieve the main research aims and a achieve study objectives the following

methodologies was applied:

Relevant data (rainfall, geology, catchment areas, meteorological data, and

social settings) about the study area was collected. And previous studies and

literatures review related to Manakha area and Manakha City were studied as

well.

A questionnaires for socioeconomic settings, current water setting and the

potential water harvesting and techniques were design and the fill.

Key informant interviews: Households, authorities (including NWSA, SDF) and

owners of existing RRH were made.

Multiple-stakeholders survey of water in the study area was conducted,

including direct water users in agriculture namely farmers, and domestic, in

addition to Agriculture Offices, NWRA,NWSA, and Water office institutions on

field level, also, a questionnaires and interviews which were made with

decision makers and NGO representatives.

The potential quantity of rainwater that can be harvested from the rooftops of

Manakha area was calculated.

A matrix for the selection process of tanks and reservoirs types was developed

based on the factors of cost, required capacity, and space area availability and

quality of water.

Data collected is analyzed using the Statistical Package for Social Science (SPSS)

program.

A results and discussion was made and conclusions and recommendations were

derived.

Finally drafting and writing the final report was done (this report will be as a

recommendation to NWSA and SDF).

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3.2 Field work description and data collection

Manakha city was divided into 15 zones (neighborhoods), so the population

density is distributed in these zones. The sample size of household survey in Manakha

town was 10% of 1300 households which represent 130 households and 1262 habitant

of the total population (7,363 people), whom are selected through a randomized

stratified cluster sampling. The fieldwork activities (data collection) started on 3rd of

March 2014 and lasted for ten days. Detailed data collection during this period is

shown in the following table.

Data collection techniques and tools

The following techniques and tools were used in data collection for household,

communities and relate authorities as mentioned in the following tables:

Table 3-1 Data collection techniques and tools at the household level.

Data collection techniques Data collection tools

Organized interview and observation Questionnaire (130 household )

Table 3-2 Data collection techniques and tools for communities and relate authorities

Data collection techniques Data collection tools

Reconnaissance walk Checklist

Men’s group discussion Discussion guide

Women’s group discussion Discussion guide

Organized interviews with a local

official & the head of the water authority

Questionnaire

Organized interviews with schools

(teachers, student)

Questionnaire

Organized interviews with healthcare

provider

Questionnaire

the metrological data Rainwater stations , soft were

Exporting maps Satellite image, ArcGIS

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3.3 Study area

3.3.1 Location

Manakha is one of the 16th districts within Sana’a Governorate. That lies in the

mid-section of the western mountain chain that stretches from the far north of Yemen

to the south. A number of other governorates surround this governorate are Amranin

the north and Dhamar in the south, Al Jowf and Maribin the east and Hodiedah in the

west and Hajja and Mahweet Governorates in the northwest.

The city of Manakha is located at 90 km west of the capital city of Sana’a with an

area about 4.3square km (400 hectare) as found from the satellite images ( Figure 3-1).

It is the administrative Centre of the Manakha district. It’s located on a mountain

ousbo bstay and roughly mid-way between Sana’a and the Red Sea port city

(Hodeidah). It is approximately at 2,250amsland lies on Haraz Mountain (Euroconsult

A., 2008).


21

Figure 3-1 Manakha location

3.3.2 Population

Manakha city was divided into 15 zones (neighborhoods), so the population

density is distributed over these zones.

During the ten year baseline period, 1994-2004, Manakha City indicate an annual

growth rate of population about 1.07 %, resulting in a population increase from 5,894

inhabitants to 6,553 inhabitants. Based on the 1.07 %annual growth rate conducting in

the 2004.According to 2004 census the population was about 6,553 inhabitants in

Manakha City. However, in year 2005 the population was 6,623 inhabitants. With five

year increments the suggested population of Manakha City according to growth rate

will be as shown in Table 3-1 below till 2025.


22

Table 3-3 Manakha Population up to 2025

Manakha 2004 2010 2015 2020 2025

Population 6,553 6,983 7,363 7,764 8,187

Families 1060 1119 1179 1243 1311

Houses 1,071 1,130 1,191 1,256 1,324

3.3.4 Geological of the Manakha area

The study area is composed of volcanic rocks of Yemen's Volcanic Series (Trap

Series), which is form almost continuous highland area in west Yemen. This highland is

dissected by wadi systems which flow to the Red Sea coastal plain. The volcanic

sequence is thick and may exceed 2,000m thick. It is composed of sub-horizontal beds

of basic to acid lavas, ignimbrites and ash flow tuffs and interflow soil horizons. North

of Manakha, granitic rocks are intrusive into the lavas.

Yemen's volcanic rocks exhibit strong regional fracture lineaments along a

dominantly NW-SE direction, as well as local fracture and faulting along NW and NE

trends. Major lineaments control the direction of the deeply dissected wadi channels.

It is possible that the geologically Tawilah Sandstone occur at a great depth

below the Manakha area; however, no boreholes have ever penetrated deep enough

to confirm this layer.

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23

Figure 3-2 Geological Map, Manakha Basin

Source: The natural resources project–Sana’a

3.3.5 Climate – Meteorological Conditions

Climate and meteorological variables which are particular to this feasibility study

include: temperature, rainfall/precipitation, evaporation / evapo-transpiration, solar

radiation, wind speed and humidity. While Yemen does have a meteorological

authority, The Civil Aviation and Meteorological Authority (CAMA) only maintains

climate data for principle cities. Table 3.4 shows a summary for the metrological data

for Manakha area and Figure 3-3shows annual rainfall for Manakha area.

Table 3-4 Shows a summary for the metrological data for Manakha area

Parameter /Month

Jan-Mar Apr-June July-Sept Oct-Dec Average

Temperature, ºC 25.6 - 6.7 28.9 - 12.1 33.2 - 15.2 31.9 - 7.0 29.9 - 10.3

Wind speed, m/s direction

3.0 Southwest

3.9 southwest

4.3 Southwest

3.5 Southwest

3.7 South

Relative Humidity

49% 47% 42% 41% 45 %

Evaporation / transpiration 1,800 mm/Year

Source: Civil Aviation and Meteorological Authority records as detailed annually2005

Statistical Year (Authority, 2005)

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Figure 3-3 Annual rainfall Isohyets map for Manakha area


25

Chapter Four

Chapter Four RESULTS AND DISCUSSIONS

4.1 Survey Result and Analysis

The sample size of household survey in Manakha town was 10% of 1300

households which represent 130 households and 1262 habitant of the total population

(7,363 people), whom are selected through a randomized stratified cluster sampling.

4.2 Household Socioeconomic Profile

4.2.1 Household Characteristics

There are 1,262 household members of which 49% males and 51% females live in

130 households. Household size is an important indicator in socio economic surveys to

estimate the demand for water consumption per capita per day and to calculate the

per capita income, and the households’ ability to pay for water delivery. The survey is

revealed that the overall average household size in Manakha is about 9members.

Household size is associated with crowding which can lead to unfavorable hygiene

conditions.

Table 4-1 Household Characteristics

Household size and

characteristics

Manakh Town ( Total )

Size or No. Percentage

Total households 130 100%

Total household members 1262 100%

Male 620 49%

Female 642 51%

Average household size 9

Dwelling ownership

Dwelling is an important factor for households in their decision to invest in the

construction of RWH or in the improvement of an existing one. Households living in

the rent dwellings maybe reluctant to invest in the installation of domestic water

harvesting or the constructing reservoir, where they will have to share with other


26

tenants in the same house. The survey revealed that 82% of the households live in

their own houses, which willingness to invest in the construction of RRWH or in the

improvement of an existing one, and 18% live in rent dwelling.

4.2.2 Household Income and Expenditure:

The monthly income level of different household is a significant indicator in the

assessment of household potential ability to pay for rainwater harvesting projects, for

improvement of an existing RWH systems, and for water supply and sanitation

services. However, the calculation of household income is methodologically difficult,

due to several factors such as unwillingness of respondents to reveal their income,

because the head of H/H is not present, or due to other problems. Therefore, the

interviewers was trained first to ask for H/H expenditure, which respondents generally

have less difficulty sharing.

When we asked about monthly income we found the higher percentage was low-

income people, where was(45% of sample) suggested they do not have sufficient

income, while only 18% suggested they have sufficient income (as shown in figure 4-1).

That, give an indicator of the need for support in case of implementing RRH projects.

Figure 4-1 Monthly income of Manakha people

Yes 18%

Totally insufficient 45%

Insufficient at times

9%

Cover only basic needs 23%

Cover some of needs

4%

Missing 1%

Yes Totally insufficient Insufficient at times

Cover only basic needs Cover some of needs Missing

ة التبويب "الصفحة الرئيسية" لتطبيق خطأ! استخدم عالم Heading 1 على النص الذي ترغب في أن يظهر هنا.

27

Water Resources Situation:

Through the results of the data analysis for main water sources for domestic uses

in the target group, is found 65% of the household a public network and tankers is a

major water source. However, there are 27% of the households using rainwater for

domestic uses, (Figure 4-2). That is an indicator for groundwater presser and depletion

but by the investment and implementation RRH project, the rainwater harvesting uses

will be increased. For example, If 50% of household will use the RRH system, this will

be increased the ratio of the households who will use rainwater for domestic uses to

50% and this will save the people income spend in water fees and value.

Figure 4-2 The main water resources for domestic uses

According to the survey the result which is conducted for the average Water

consumption (L / day/ per capital) is 28-30 L / day/capita (see Figure 4-3). This is in line

with the average per capita consumption in rural and urban areas (30 - 40 L / day) in

Yemen.

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28

Figure 4-3 Water consumption (L / day ) per capital

According to the survey the result which is conducted for the price of water unit from

public network is 400YR/ m3.

Figure 4-4 The price of water unit from public network

Means, frequency and time spent fetching water from the source

Further analysis for the means time of fetching water for house water supply,

shows that about 53% of adults (boys, girls) who are fetching water from the source

and they are making an effort and suffering to supply water for houses from a long

distances (5 km). While only about 47% of women, men who are supplied water for

house. The trip is mostly made on foot or by donkeys. Most of these households


29

reported, that they spend an average of three trips per day for fetching water, and

each trip takes an average of one hour. All this turn adversely affection the education

deprivation, wasting time, health, social and economic situation. In the case of water

provision from alternatives water sources such as rainwater harvesting from rooftops,

it is possible to provide water for house and save the water cost and have effort in

other economic work . For example, the women can work in sewing and girls can be

assimilating in the education phases. This will help to improve the per capita income

level and the development of economic and social status in the region, (see Table 4-2).

Table 4-2 Means, frequency and time spent fetching water from the source

No Question Manakha area

Analysis

27 Who is fetching water and supplied to your house?

Number Percentage

Girls 53 27%

Boys 50 26%

Women 52 27%

Men 39 20%

28 How much times spend to fetch drinking water from the source (springs)?

Number Percentage

1/2 hour 21 21%

One hour 42 43%

2 hours 21 21%

3 hours 11 11%

More than 3 hours 4 4 %

32 How much time spend to fetch water for domestic and other uses?

Number Percentage

1/2 hour 32 31%

One hour 41 40%

2 hours 19 19%

3 hours 7 7%

More than 3 hours 3 3%

29 How many times in a day, do you go fetching drinking water?

Number Percentage


30

Once 22 22%

Twice 24 25%

Three times 28 29%

More than three 23 24 %

33 How many times in a day, do you go fetching water for domestic and other uses?

Number Percentage

Once a day 19 19%

Twice a day 25 25%

Three times a day 30 29%

More than three times a day 26 25%

Once a week 2 2%

30 How much (amount) of water do you

carried in once time for drinking? Number Percentage

10L 17 18%

20L 35 36%

40L 17 18%

More than 40 L 27 28%

34

How much (amount) of water do you

carried in once time for domestic and other

uses?

Number Percentage

10L 12 12%

20L 38 37%

40L 20 20%

More than 40 L 31 31%

4.2.3 Inhabitants Opinion about RRH:

Another measured factor for RRH uses is the inhabitants opinions and willingness

to use RRH.As a result from the survey, Only 18 % of inhabitants didn't like the use

RRH, as shown in (Figure 4-5).However, their reasons for this objection are illustrated

in(Figure 4-6 ). The other majority the inhabitants about 80 % are encouraging the idea

of using RRH systems. This is an indication of the awareness of inhabitants in the

خدم عالمة التبويب "الصفحة الرئيسية" لتطبيق خطأ! است Heading 1 على النص الذي ترغب في أن يظهر هنا.

31

region to encourage investment on RRH in this area. However, there is no social impact

that could hinder the implementation of such projects in this area.

Figure 4-5 Inhabitants opinions and willingness to use RRH

Figure 4-6 People reasons of not encouraging, sharing RRH

The majority of people with high rate of 94% respondents give their willingness

and ability to participate in such projects (see Figure 4-7). Farther, most of the people,

who encouraged the idea of RRH are not willing to participate financially, while, 47% of

the samples are willing to participate financially and share in work. However there are

some people willing to provide financial support even though they either retired, while

42% of interviewees are willing to participate in sharing in the work. In additional the

women who have shown their willingness to participate in the establishment of such

projects (harvesting projects) to the possible extent even they will soled their gold to

Yes for RTRWH

80%

No 18%

Missing 2%

Yes

No

Missing

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32

participate and create harvesting project in order to alleviate the suffering of fetching

water over long distances. This is also a social indicator and a positive evidence of the

urgent need for water in thisregion.

Figure 4-7 Interviewees’ willingness and ability to participate in RRH projects

Farther, in case of applying (RRH projects), the interview of the households were

conducted and the result is mentioned in (Figure 4-8). This result shows that the

majority of them as 50% will use the harvested rainwater for all domestic uses, while

41% of the respondents are happy to use rooftop rainwater for all domestic uses

except drinking. In this case, the determination of the purity of the harvest water and

raise the level of awareness among citizens through many channels can join this

community to community, which will be used harvesting water for all purposes,

including drinking and this ratio of up to 91% and this is an excellent index.


33

Figure 4-8 Different uses of rainwater when applying RRWH projects

In general, Water insufficiency in the region, is a sign of the fear of citizens in

the depletion of the water. So when they are asked about the solutions of this

situation they answered in insistence, the use of rainwater harvesting. Where this

renewable source will support and develop the technology for irrigation, as well as

prevent the indiscriminate wells drilling in the region. In addition, to the work in water

barriers for groundwater recharge, which in turn is resolved to face water scarcity in

the region.

Moreover, when they are asked about the future of society solutions to face

water supply in the region, about 68% of the community said it is resolved with the

construction of dams and barriers for groundwater recharge. This view is dominant on

people without studied scientifically and economic feasibility.

4.3 Roof Tops Area Estimation in Manakha city:

The total surface area of Manakha City has been estimated using Google earth

data to be about 0.138 km2. The maps is built out of Google Earth data. This was done

by mosaicking which means taking several raster datasets as a picture of the specific

scene. After preparing these scenes, the raster datasets were put together by merging

all the scenes. The result is a high resolute map. To get information about the area

taken by rooftops we need to separate the rooftops from the rest of the map. The

total area of rooftops isabout138189.65m2 (figure 4-9).


34

Figure 4-9 Image of Manakha city showing the rooftops areas in yellow

4.4 Tanks Sizes and Techniques of RRH

Generally, in Manakha the largest expensive part of the water systems is the

storage tank due to the limited available area. The cost of tank is based upon the size

and the material type of tank such as: steel, concrete and plastic tanks, which are the

most common used types. In this study the potential and appropriate type of tanks for

Manakha city depends on two factors, the income and space area available. Farther,

the cost of the tank has been taken as a main factor of the selection process in this

research. In poor and crowded zones, steel and plastic tanks are used, while the

concrete tanks are more used in rich zones. In general the concrete tanks are

indicated and discussed as appropriate tanks that can be installed in different areas

among the city. Table (4-3) shows a range of potential tank materials and related costs

per cubic meters of storage.


35

Table 4-3 Appropriate tanks types and cost estimation in Manakha

Tanks Capacity

(m3)

Cost $/

m3 Source Comments

Concrete < 100 110 – 180 SFD Risks of cracks and leaks but it

is easily repaired

Block tank < 20 75-100 SFD

Brick cement 1– 30 10 – 40 Calculation

Fe rrocement 50 – 100 47 – 65 SFD Risks of cracks and leaks but it

is easily repaired

Masonry 850-

1700 16- 50 Calculation

Risks of cracks and leaks but it

is easily repaired;

Steel 5 42 Invoice

Sentik (plastic) 5 120 Invoice

4.5 Tanks Places Selection

In Manakha city, the tanks places selection are identified to five steps:

Non-crowded areas where is enough space areas, Concrete tanks are suggested

for the required volume up to 40m3.

Crowded areas where there is no enough space for installing big tanks, steel

and plastic tanks are suggested for the required volume up to 4m3 for every

household. Also, general concrete tank is suggested with required volume up to

500m3for all neighborhood.

Public and big buildings such Authorities, Schools, Hospital, Mosques, which

require more capacities, the underground storage Ferro cement tank is

installed where required volume up to 100 m3.

In case of more storage capacity is needed and there is enough area for

installing big tank but building this tank must be, above or underground, block

or concrete tanks are used. So for storage capacity up to 20m3 block tanks are

used, and for more volume concrete tanks are used, where the most expensive

choice among suggested tanks is used.

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36

The areas of already existing tanks, and redesign of the system should be

carried out. If there is not replacement, rehabilitation or/and additional tank

may be needed.


37

Chapter Five

CONCLUSION AND RECOMMENDATION

5.1 Conclusion

In Manakha city the Public water network are insufficient supply by NWSA

In Manakha city rain water harvesting currently being used only by 27% of the

households

RRH contribute in Relieve the pressure on ground water

Harvested roof rainwater can be used for all uses (filtering before drinking)

RRH is applicable, feasible and more reliable than water from other unknown

and infrequently tested sources

General tanks for water harvesting and shared with water project within the

system( NWSA) for the purpose of operation, maintenance and sustainability,

thus relieve the pressure on groundwater

Rain water harvesting currently being used by 27% of the households

Gender sensitive analysis and stakeholder participation aid to choose

acceptable technologies and design of effective management and financial

systems.

Women have been shown their willingness to participate in the establishment

of such projects, so that they will soled their gold to participate and create

harvesting project.

5.2 Recommendations

1. Raise awareness among the people in the region through the media,

workshops, as a first step to define the importance and use of rainwater

harvesting.

2. More research on the application of IWRM in water projects to improve and

develop water management.

3. Rainwater harvesting should be defined as a necessity, not an option

4. Need for coordination and cooperation between the relevant government

institutions private sector and urban, ruler households is required for access to

Better water management.


38

5. Setting of laws, regulations, and building codes to use WH in old and new

buildings is recommended.

6. Rehabilitation of old systems (ponds, caravans, dams), especially those parked

near the buildings and use modern harvesting technology for access to high-

water quality for domestic use .

7. Find incentive funding to support water harvesting projects with the

participation of the community, for example, the introduction of (SFD) and

other funds projects to finance support such projects that’s encourage citizens

and do awareness about the RRH.

8. Trend government, NGOs to implementation RRH system as first step in the

region to encourage all people, stakeholders' relevant agencies.

9. Recommend, work of barriers at the downstream to recharge the groundwater

wells, springs to sustainable water through the dry season.

10. Using silver filters, etc. in household for drinking RRH is recommend.

11. RRH systems on building degassing is required.


39

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