Roof Water Harvesting

APPRAISAL OF ROOF WATER HARVESTING AND ITS POTENTIAL FOR PRODUCTIVE USES IN NORTHERN GHANA

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Draft, IWMI and SARI

TABLE OF CONTENTS ACRONYMS AND ABBREVIATIONS……………………………………………1 CHAPTER ONE

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INTRODUCTION

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1.1 BACKGROUND .......................... ........................................ ............................ ............................ ............................ ............................ ............................ ............................ ...................... ........ 4 1.2. THE EXTENT OF WATER PROBLEMS WHERE RAINWATER HARVESTING SYSTEMS ARE USED .. 6 1.3 GLOBAL USE OF RAINWATER HARVESTING IN SOLVING WATER PROBLEMS ............................... ............................... 7 ‐

CHAPTER TWO

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REVIEW OF ROOF WATER HARVESTING…………… HARVESTING………………………………..... ………………….....10 2.1 ROOF WATER HARVESTING ................ .............................. ............................ ............................ ............................ ............................ ............................ ...................... ........ 10 .............................. ............................ ............................ ........................... ................. .... 10 2.2 IMPORTANCE FOR DOMESTIC WATER SUPPLIES ................ 2.3 RAINWATER HARVESTING COMPONENTS ................ .............................. ............................ ............................ ............................ ........................... ............. 11 .............................. ............................ ............................ ............................ ............................ ............................ ...................... ........11 2.3.1 Catchment Subsystem Catchment Subsystem ................ .............................. ............................ ............................ ............................ ............................ ............................ .................... ......12 2.3.2 Conveyance Subsystem ................ ............................... ............................ ............................ ............................ ............................ ............................ ........................... .............13 2.3.4 Storage Subsystem ................. ............................. ............................ ............................ ............................ ............................ ............................ ........................... .............19 2.3.4 Filtering 2.3.4 Filtering Subsystem Subsystem ............... ............................... ............................ ............................ ............................ ............................ ............................ ............................ ........................ .......... 19 2.3.5 Distribution ................. .............................. ......................... ........... 20 2.4 WATER QUALITY OF ROOFTOP RAINWATER HARVESTING SYSTEMS ................ 2.6 SITE AND RAINWATER HARVESTING SYSTEM SELECTION ................ .............................. ............................ ............................ ................ 22 ............................. ............................ ............................ ............................ ............................ ............................ ............................ ............................ .................... ...... 22 2.6.1 Rainfall............... ............................... ............................ ............................ ............................ ............................ ................. ...2233 2.6.2 Hydrology 2.6.2 Hydrology and Water Resources Water Resources ................. ............................... ............................ ............................ .................... ......23 23 2.6.3 Socio Economic and Infrastructure Conditions ................. .............................. ........................... ............................ ............................ .................... ......2233 2.6.4 Environmental and Ecological Impacts ................. ............................... ............................ ............................ ............................ ............................ ............................ ............................ ............................ ...................... ........ 24 2.6.5 Costs ................. ............................. ............................ ............................ ............................ ............................ .................... ......2244 2.7 Water 2.7 Water Balance Balance and System Sizing ............... .............................. ............................ ............................ ............................ ............................ ............................ ........................... .............25 2.7.1 Supply Calculation ................ ............................... ............................ ............................ ............................ ............................ ............................ ........................ ..........25 2.7.2 Demand Calculation................. ............................... ............................ ............................ ............................ ............................ ...................... ........2266 2.7.3 Storage Capacity Calculation ................. 2.8 POTENTIAL EFFECTS AND IMPACTS – TAKING A LIVELIHOODS BASED APPROACH.................. .................. 27 .............................. ............................ ............................ ............................ ............................ ................. ...2288 2.8.1 Reduction of Burdens of Burdens of the of the Poor ................ ............................... ............................ ............................ ........................... ........................... ............................ ............................ .................... ......28 2.8.2 Health 2.8.2 Health Impacts ................. .............................. ............................ ............................ ............................ ............................ ............................ ............................ ...............30 . 2.8.3 Economic Impacts ................ ............................. ............................ ............................ ............................ ............................ ............................ ........................... .............30 2.8.4 Poverty Alleviation Poverty Alleviation ............... ............................... ............................ ........................... ........................... ............................ ............................ .................... ......31 2.8.5 Environmental Benefits................. .............................. ............................ ............................ ............................ ............................ ................. ...3311 2.8.6 Domestic and Industrial Benefits ................ 2.9 PLANNING AND MANAGEMENT OF RAINWATER HARVESTING SYSTEM .................................... .................................... 31 3. THE CASE OF NORTHERN GHANA……………………………………………………………….3 ‐

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REFERENCES

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Acronyms and Abbreviations AEZ ASA DRWH DTU FAO IDRC IWMI MDGs MLGLH PAF PRAs RHAZ RWH RWHS SARI SSA SIDS SIWI UNICEF UNEP UNCESCR Rights WH WHO

Agro Ecological Zone Arid and Semi‐arid Domestic Rainwater Harvesting Development Technology Unit Food and Agriculture Organization of the United Nations International Development Research Centre International Water Management Institute Millennium Development Goals Ministry of Local Government, Land and Housing, Botswana Agro‐Forestry Project Principal Research Areas Rainwater harvesting Association of Zimbabwe Rainwater Harvesting Roof Water Harvesting System Savanna Agricultural Research Institute Sub‐Saharan Africa Small Island Developing Countries Stockholm International Water Institute United Nation Children’s Fund United Nations Environment Programme United Nations Committee on Economic, Social and Cultural Water Harvesting World Health Organization 3


CHAPTER ONE INTRODUCTION 1.1 Background Water is fundamental for life and health. The human right to water is indispensable for leading a healthy life in human dignity. It is a pre‐requisite to the realization of all other human rights (UNCESCR, 2002). In spite of this, a large proportion of the world’s population does not have access to safe sources of water. WHO/UNICEF has estimated that 1.1 billion people do not have access to “improved drinking‐water sources” (WHO/UNICEF 2000). Despite major efforts to deliver safe, piped, community water to the world’s population, the reality is that water supplies delivering safe water will not be available to all people in the near future. The Millennium Declaration by the WHO established a goal of halving the proportion of the global population without access to safe water by 2015. It is clear that all possible approaches must

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be tried to mitigate the problem of drinking water, maximizing the control of households with regard to their own water security. In this context, rainwater harvesting is receiving increased attention worldwide as an alternative source of drinking water. Rainwater harvesting has been a popular technique in many part of the world, especially in arid and semi‐arid regions (almost 30% of the earth’s surface). Rainwater harvesting was invented independently in various parts of the world and on different continents thousands of years ago. It was especially used and spread in semi‐arid areas where rainfall occurs during some months and at different locations. The application of appropriate rainwater harvesting system can make possible the utilization of rainwater as a valuable and in many cases, necessary water resources. Rainwater harvesting has been practiced for more than 4000 years, and, in most developing countries, is becoming essential owing to the temporal and spatial variability of rainfall. Rainwater harvesting is necessary in areas having significant rainfall but lacking any kind of conventional, centralized government supply system, and in areas where good quality fresh surface water or groundwater is lacking While rainwater may be harvested in a number of ways, this paper focuses only on the collection and storage of rainwater from individual household roof catchments. Traditionally this was the major option to people in water‐scarce regions in rural areas of developing countries where people had to manage to fulfil drinking water and household water needs by rainwater harvesting. Governmental agencies across the world are now introducing policies to promote increased use of rainwater. In India, for example, several state governments have introduced legislation that makes it obligatory to incorporate rooftop rainwater harvesting systems in newly constructed buildings in urban areas. (Meera and Mansoor, 2006) Governments are also providing subsidies to promote the use of rainwater harvesting systems. The Ghana Science Association, GSA organized workshop on the theme: “Rainwater Harvesting: A sustainable Solution to Water Shortage Problems in Ghana” to create forum for cross fertilization of ideas among stakeholders on the subject with a view to evaluating rainwater harvesting as a sustainable practical solution to the perennial water shortage problems in the country. (Daily Graphic, 2006). In Ghana, rainwater harvesting is being practiced especially at Tema and some places in the Northern sector for domestic purposes but the technology is not fully developed for agricultural use. (Anane, 2000) RWH technology is low cost and simple. RWH technologies have a high potential of contributing towards the Millennium Development Goals (MDGs) with a view of eradicating poverty and hunger, provision of safe drinking water 5


and sanitation, ensuring environmental sustainability, promoting gender equity and women empowerment. It is one way of improving the living conditions of millions of people, particularly those living in the dry areas. Water scarcity especially for domestic and agricultural purposes compromises the role of women in food production. Hence, provision of water by promoting rainwater harvesting and management technologies reduces the burden for rural women thus increasing their productivity. The provision of water at the point of consumption from rainwater tanks provides a range of immediate positive social impacts on health, family welfare and domestic productivity. This results when time saved in water collection is utilized elsewhere. Some of the time saved maybe used for productive activities such as agriculture with clearly tangible and easily valued economic benefits. More time can also be spent on activities such as child rearing when women have time freed up from the daily chore of water collection. The value of such benefits to family livelihood and well‐ being are difficult to assess and are rarely appropriately costed. The aim of this paper is to create awareness of successful methods or systems of roof water that resource poor farming households have effectively used to overcome the hardships of nature. 1.2. The Extent of Water Problems Where Rainwater Harvesting Systems Are Used ‐

Successful applications of this domestic rainwater harvesting are used in Amman (Jordan), Edlib and Quneitra (Syria), West Bank highlands (Palestine) and Lebanon, where annual rainfall varies between 300‐500 mm. The practice was also historically used in drier climates in Yemen (Aden) and Syria (Rasafe). In the semi‐arid zones of West Asia, about 65‐80% of the annual rainfall occurs during an approximately four‐month period, with the remaining months having little or no rainfall. Accordingly, rainwater harvesting from residential rooftops represents a viable alternative under certain natural and demographic conditions this will help solve the problem of inadequate domestic water during the dry season and throughout the whole year. (UNEP, 2000b). Katsukunye about 170 kilometre (km) away from Harare, Zimbabwe was well known for perennial water shortage. As the functioning of the local school and clinic also started getting adversely affected, the Ministry of Health and Child Welfare was on the verge of closing down. However, the community ʹs endeavour to harness rainwater and evolve rules for its sustainable management is saving several lives, everyday. About 120 people in the clinic and 700 students 6


are its main beneficiaries. Earlier, absence of rainwater harvesting (RWH) system and adverse hydro geological features like rocky terrain and saline groundwater had intensified the crisis. Pregnant women were the most affected, as the potable drinking water source was almost three km away. (Catch Water, GWP News, 2003) Kooki County in Uganda has very difficult physical and climatic conditions for drinking water supplies. A programme to introduce simple rainwater harvesting techniques in selected households has successfully prompted replication throughout the district on a self‐financing basis. (One World Africa, 2004) 1.3 Global use of Rainwater Harvesting in Solving Water Problems Sri‐Lanka is one place that rainwater is harvested for domestic purpose. Sri‐ Lanka is classified as a country with little or no water scarcity. However, the picture has been made clearer by another classification that divided that country into absolute water scarce districts and economic water scarce districts depending on seasonality. Absolute water scarcity in this instance has been defined as when water abstraction is more than 50% of available water. According to this classification almost all dry regions in Sri Lanka face year round or absolute water scarce conditions. Economic scarcity has on the hand been defined in terms of the magnitude of future development. The rainwater is used for several domestic activities including flushing of toilet, washing, cooking and drinking (occasionally) (Lanka Forum, 1999). Mvuramanzi Trust, a member of Rainwater harvesting Association of Zimbabwe (RHAZ) with community participation constructed a 192 square metres catchment with 15 cubic metre storage tank using granite rocks near the school on a smooth rock surface for the Katsukunye Community in 2001. The project has provided significant economic and environmental gains. A marked improvement has also been noted in the childrens school performance. Cases of diarrhoea and unhygienic child delivery have reduced considerably. The women now have more time to invest in productive ventures. Adequate gully control measures have helped to control environmental degradation around the granite rocks. Rainwater harvesting is used extensively in Latin America and the Caribbean, mainly for domestic water supply and, in some instances for agriculture and livestock supplies on a small scale. In Brazil and Argentina, rainwater harvesting is practiced in semi‐arid regions. In Central American countries like Honduras,

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Costa Rica, Guatemala, and El Salvador, rainwater harvesting using rooftop is employed extensively in rural areas. Estimates show that about 100,000 people in rural Jamaica depend to a large extent on rainwater harvesting (UNEP, 1997). Domestic rainwater harvesting technology widely applied in areas of West Asia where the annual rainfall ranges between 350‐500 mm, especially in the mountainous terrain of Syria, Lebanon, Jordan, Palestine and Yemen has been very helpful. It has also been applied to a certain extent in Saudi Arabia and the Sultanate of Oman. The eastern Mediterranean hills, which receive a high rainfall quantity of 500‐1000 mm/year, also resort to this technology due to the deep groundwater aquifer, the non‐ uniform spatial distribution of the rainfall due to the widespread karst structures, and the high velocity of surface and subsurface water runoff. This results in the high availability of water during the rain seasons and in water scarcity during the dry seasons. Domestic rainwater harvesting has helped households obtain water for most parts of the year. (UNEP, 2000b). Rainwater collection systems are extensively used by most SIDS, (Small Island Developing Countries) especially those low‐lying islands where rainwater catchments constitute the major part of the water supply for the inhabitants. This supply will often be supplemented by groundwater. Some of the Islands include St. Lucia, the Turks and Calicos Islands. In some places government regulations make it mandatory for developers to build rainwater storage tanks. Rooftop and purpose ‐ built catchments also are commonplace in the Bahamas. One settlement (Whale Cay) has a piped distribution system based on rooftop‐collected water. On New Providence, most of the older houses collect rooftop rainwater and store it in tanks averaging 70000 litres capacity. Industrial use of rooftop‐collected rainwater is also practiced. The Islas de la Bahia, off the coast of Honduras, meets a substantial proportion of their potable‐water needs from rooftop catchments. Rainwater catchment systems are practically the sole water supply source for a small group of islands north of Venezuela; these arid islands experience only 500 mm to 700 mm of rainfall per year, and have largely saline groundwater reserves that cannot be used for potable purposes (UNEP, 2000c). Ethiopia is also one country that roof water harvesting has been practiced for some time due to the incidence of dry spells which results in undesirable consequences such as famine and shortage of water for other domestic activities. In high land areas where the terrain is rugged with scattered villages and hamlets developing modern water supply systems is a problem. As a result roof water harvesting has been considered as a viable development option. It is also a means of water supply in areas where ground water is not feasible and perennial

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streams/rivers do not exist. Roof water from schools, churches and individual homes with corrugated roofs are under trial in several areas and the results so far are very encouraging. Adequate water is therefore provided during the rainy season, an occasion where the rural communities are busy with their farming. More and more people are harvesting roof water, as more and more people own houses with corrugated roofs (Alem, 1999). Due to inadequate piped water supplies, the University of Dar es Salaam has applied rainwater harvesting and utilisation technology to supplement the piped water supply in some of the newly built staff housing. Similarly, rainwater is collected from the hipped roof made with corrugated iron sheets and led into two tanks, each with a 70‐litre capacity. The town and district councils under the Ministry of Local Government, Land and Housing (MLGLH) have constructed thousands of roof catchment and tank systems at a number of primary schools, health clinics and government houses throughout Botswana. (UNEP, 2000) Domestic roof water harvesting in the context of South Asia and East Africa were initiated as a source of domestic water especially for drinking and cooking. This was mainly due to the belief that quality of rainwater is better than the commonly found ground water. However, stored water is used for various activities other than drinking and cooking. This in fact was quite evident in the Sri Lankan rainwater‐harvesting programme, especially in the wet zone, where stored water are mainly used for non‐premium water use activities (washing clothes, sanitary purposes, livestock and small‐scale home gardening). This gave the users the added advantage of having a source of water within accessible distance for household use. Experiments conducted in Sri Lanka and Rwanda indicate that improving accessibility of water has increased the per capita consumption of water and increased the rainwater contribution in the total use of rural households. Studies conducted by the Anawan Trust in Tiruchendur Taluk on roof water harvesting from community centers, among coastal fishing villages, indicated that harvested rainwater has particularly benefited children, and 80 % of the people in the area said that water shortage in summer has been overcome by roof water harvesting. (Milestone Report D 5, 2001).

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CHAPTER TWO REVIEW

2.1 Roof Water Harvesting Roof water harvesting is the collecting of runoff during rains from impermeable surfaces on houses or close to houses, its storage in waterproof vessels and its subsequent use as the water supply of the inhabitants of the houses. The use may be “temporary” (for example during the 24 hours following a rainstorm), “seasonal” (throughout the rainy season) or “permanent” (throughout the year except perhaps in years of exceptionally low rainfall. Rooftop rainwater harvesting for household use will only ever represent a small part of the total water balances. In areas with significant variations in the annual rainfall pattern, matching water supply and demand may be difficult. However, in terms of economic and human welfare it has a crucial role to play. Rainwater is in many cases the easiest to access, most reliable, and least polluted source, in addition, because it can be collected and controlled by the individual household or community as it is not open to abuse by other users. Rainwater pollution/contamination may result from air pollution and biological contamination. 2.2 Importance for Domestic Water Supplies Rainwater harvesting systems have a high potential in many countries and are already being widely used not only in ASA environments. Rooftop rainwater harvesting has a number of potential benefits including: 1. The water source is close to people, so it requires a minimum of energy to collect it and therefore it is very convenient. 2. A reduction of the burden of collecting water over long distances; particularly for women 3. Improved health due to cleaner water, improved sanitation, reduced drudgery (previous point), and improved nutrition (through growing vegetables) 4. Reduction in vulnerability to external shocks such as drought, and a diversification of livelihoods due to productive and economically beneficial uses of water

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5. Poverty alleviation through productive use of water, but also through capacity building, reduced isolation, and improved access to basic services as part of the implementation process. 6. Control flood – thus greatly reducing urban runoff. 7. Stormwater drainage ‐ by reducing the size and scale of infrastructure requirements; 8. Firefighting and disaster relief ‐ by providing independent household reservoirs; 9. Water conservation ‐ as less water is required from other sources; 10. Reduced groundwater exploitation and subsidence ‐ as less groundwater is required; 11. Financial savings ‐ where rainwater can be used in place of water purchased from water vendors often charging up to 10‐50 times the official water tariff.

2.3 Rainwater Harvesting Components A rainwater harvesting system consists of the following subsystems: catchment area (roof), conveyance system (guttering, downspouts, and piping), filtration, storage (cistern), and distribution. . 2.3.1 Catchment Subsystem The catchment determines the quantity and to some extent the quality of water that enters the tank. Most losses are through infiltration, although some water will also bounce off the edge of the surface in heavy downpours and usually some water will be lost in wetting the surface. The loss is usually represented by a ʺrun‐off coefficientʺ CR which is a number between zero and one: (1‐ CR) expresses the loss fraction averaged over a year. A good impermeable roof such as corrugated iron will deliver to the guttering system almost all of the water that lands on it. Ground catchments tend to have a lower runoff coefficient as rainwater infiltrates into the ground and flows away as groundwater. Runoff quality also varies by catchment type. Ground catchments are prone to contamination from many sources including human and animal faecal matter, rotting vegetation and the soil itself. Higher quality water for drinking must be caught from a surface that is less easily contaminated. This usually comes in the form of the roof of the building but can be a separate structure. GI sheet roofs 11


fare best due to their relative smoothness (Fujioka, 1993) and the sterilising effect of the metal roof heating under the sun (Vasudevan, Tandon, Krishnan, & Thomas, 2001). Catchments include natural slopes or sealed catchments, rocks, roofs, roads and flood water from seasonal rivers Rooftop Catchments In the most basic form of this technology, rainwater is collected in simple vessels at the edge of the roof. Variations on this basic approach include collection of rainwater in gutters that drain to the collection vessel through down‐pipes constructed for this purpose, and/or the diversion of rainwater from the gutters to containers for settling particulates before being conveyed to the storage container for the domestic use. As the rooftop is the main catchment area, the amount and quality of rainwater collected depends on the area and type of roofing material. Reasonably pure rainwater can be collected from roofs constructed with galvanized corrugated iron, aluminium or asbestos cement sheets, tiles and slates, although thatched roofs tied with bamboo gutters and laid in proper slopes can produce almost the same amount of runoff less expensively (Gould, 1992). However, the bamboo roofs are least suitable because of possible health hazards. Similarly, roofs with metallic paint or other coatings are not recommended as they may impart tastes or colour to the collected water. Roof catchments should also be cleaned regularly to remove dust, leaves and bird droppings to maintain the quality of the product water. 2.3.2 Conveyance Subsystem Conveyance systems are required to transfer the rainwater collected on the rooftops to the storage tanks. This is usually accomplished by making connections to one or more down‐pipes connected to the rooftop gutters. When selecting a conveyance system, consideration should be given to the fact that, when it first starts to rain, dirt and debris from the rooftop and gutters will be washed into the down‐pipe. Thus, the relatively clean water will only be available some time later in the storm. There are several possible choices to selectively collect clean water for the storage tanks. The most common is the down‐pipe flap. With this flap, it is possible to direct the first flush of water flow through the down‐pipe, while later rainfall is diverted into a storage tank. When it starts to rain, the flap is left in the closed position, directing water to the down‐ pipe, and, later, opened when relatively clean water can be collected. A great 12


disadvantage of using this type of conveyance control system is the necessity to observe the runoff quality and manually operate the flap. An alternative approach would be to automate the opening of the flap as described below. A funnel ‐shaped insert is integrated into the down‐pipe system. Because the upper edge of the funnel is not in direct contact with the sides of the down‐pipe, and a small gap exists between the down‐pipe walls and the funnel, water is free to flow both around the funnel and through the funnel. When it first starts to rain, the volume of water passing down the pipe is small, and the *dirty* water runs down the walls of the pipe, around the funnel and is discharged to the ground as is normally the case with rainwater guttering. However, as the rainfall continues, the volume of water increases and *clean* water fills the down‐pipe. At this higher volume, the funnel collects the clean water and redirects it to a storage tank. The pipes used for the collection of rainwater, wherever possible, should be made of plastic, PVC or other inert substance, as the pH of rainwater can be low (acidic) and could cause corrosion, and mobilization of metals, in metal pipes. In order to safely fill a rainwater storage tank, it is necessary to make sure that excess water can overflow, and that blockages in the pipes or dirt in the water does not cause damage or contamination of the water supply. The design of the funnel system, with the drain‐pipe being larger than the rainwater tank feed‐pipe, helps to ensure that the water supply is protected by allowing excess water to bypass the storage tank. A modification of this design has a simple overflow/bypass system. In this system, it is possible to fill the tank from a municipal drinking water source, so that even during a prolonged drought the tank can be kept full. Care should be taken, however, to ensure that rainwater does not enter the drinking water distribution system 2.3.4 Storage Subsystem The storage tank (cistern) must be sized properly to ensure that the rainwater potential is optimized. Cisterns can be located above or below ground. The best materials for cisterns include concrete, steel, ferro‐cement, and fiberglass. When ordering a cistern, specify whether the cistern will be placed above or below ground and if the cistern will be used to store potable water. (Fiberglass cisterns are constructed differently to meet the various criteria.) (Sourcebook, Harvested Rainwater, 1994) Cistern characteristics 1 A cistern should be durable and watertight. 2 A smooth clean interior surface is needed.

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3 Joints must be sealed with non‐toxic waterproof material. 4 Manholes or risers should have a minimum opening of 24 inches and should extend at least 8 inches above grade with buried cisterns. 5 Fittings and couplings that extend through the cistern wall should be cast‐ in‐place. 6 Dissipate the pressure from the incoming water to minimize the stirring of any settled solids in the bottom of the cistern. This can be accomplished in a concrete cistern by placing concrete blocks (cavities facing upward) surrounding the base of the inlet pipe. The blocks can be 8ʺx 8ʺx16ʺ blocks with the pipe exiting one inch above the bottom of the cistern. Baffles to accomplish the same result can be made as part of fiberglass cisterns. This is not a concern for cisterns that always have a large reserve. 7 The use of two or more cisterns permits servicing one of the units without losing the operation of the system. 8 Have a fill pipe on the cistern for adding purchased water as a backup. 9 Have a cover to prevent mosquito breeding and algae growth from contact with sunlight. Commonly used storage subsystems are as follows: Storage Tanks Storage tanks for collecting rainwater harvested using guttering may be either above or below the ground. Precautions required in the use of storage tanks include provision of an adequate enclosure to minimize contamination from human, animal or other environmental contaminants, and a tight cover to prevent algal growth and the breeding of mosquitoes. Open containers are not recommended for collecting water for drinking purposes. Various types of rainwater storage facilities can be found in practice. Among them are cylindrical Ferro cement tanks and mortar jars. The storage capacity needed should be calculated to take into consideration the length of any dry spells, the amount of rainfall, and the per capita water consumption rate. In most of the Asian countries, the winter months are dry, sometimes for weeks on end, and the annual average rainfall can occur within just a few days. In such circumstances, the storage capacity should be large enough to cover the demands of two to three weeks. Rainfall Water Containers

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As an alternative to storage tanks, battery tanks (i.e., interconnected tanks) made of pottery, ferro‐cement, or polyethylene may be suitable. The polyethylene tanks are compact but have a large storage capacity (ca. 1 000 to 2 000 l), are easy to clean and have many openings which can be fitted with fittings for connecting pipes. In Asia, jars made of earthen materials or ferrocement tanks are commonly used. During the 1980s, the use of rainwater catchment technologies, especially roof catchment systems, expanded rapidly in a number of regions, including Thailand where more than ten million 2 m3 ferrocement rainwater jars were built and many tens of thousands of larger ferrocement tanks were constructed between 1991 and 1993. Early problems with the jar design were quickly addressed by including a metal cover using readily available, standard brass fixtures. The immense success of the jar programme springs from the fact that the technology met a real need, was affordable, and invited community participation. The programme also captured the imagination and support of not only the citizens, but also of government at both local and national levels as well as community based organizations, small‐scale enterprises and donor agencies. The introduction and rapid promotion of Bamboo reinforced tanks, however, was less successful because termites, bacteria and fungus attacked the bamboo. More than 50 000 tanks were built between 1986 and 1993 (mainly in Thailand and Indonesia) before a number started to fail, and, by the late 1980s, the bamboo reinforced tank design, which had promised to provide an excellent low‐cost alternative to ferrocement tanks, had to be abandoned. Partially Below Ground Tank for Rainwater Storage The partially below ground tank incorporates the merits of both above and below ground in one simple design. There is no need for structural component beneath it since it takes support from the ground. It has protection against contamination from surface run‐off and damage by vehicles. These tanks are used in Uganda using render linings. The reports from the field have been good suggesting that the tanks are easy to construct. The advantages include the fact that the above ground structure allows for easy inspection for cracks or leakages and can be manufactured from a wide variety of materials, easy to construct from traditional materials. On the other hand, it requires space, generally more expensive, more easily damaged, and prone to attack from the weather and could be dangerous when constructed on soils that are unstable. (DTU, 2000) Single Skin, Externally Reinforced, Brick Tank This has been designed to minimize material input. It has not got enough hoop strength to withstand the stresses imposed by the internal water pressure so it is ‐

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externally reinforced with packaging strap. The packaging straps also reduce the amount of bricks needed to construct the tank. The capacity of the tank is approximately six cubic metres, with an internal diameter of 2.0m and a height of 2.0m. (DTU, 1999) Tarpaulin’ Lined Tank This is used in southern Uganda. This 6000‐litre tank is made by lining a 3m x 2m x 1m deep hole with a standard UNHCR blue tarpaulin (5m x 4m rip‐stop plastic with eyelets near the edge). The tarpaulin is held up with string from nails down to these eyelets. A simple wall (wattle and mud, 600mm high) is built around the tank and roofed with slightly sloping corrugated iron sheets. The wall is lined with plastic sacking to prevent mud falling into the water. The wall‐roof joint is sealed with mud. Water enters via a hole in the roof sheeting (covered by a filter cloth and fed by a sloping metal down pipe). Water is extracted by dipping with a modified (cut‐away) 10‐litre jerry can via a small wooden door in one wall ‐ water is always within armʹs reach. Some work has been done on developing a low‐cost hand pump to extract water. There is normally no overflow and the householder is expected to move aside the down pipe feeding the store when the water level approaches the top of the tarpaulin lining

The Ferro Cement Jar ‐

This jar has been built in areas like Kyera in Uganda. It consists of a brick plinth, a ferro‐cement shell and a filter basin. This technology has been very successful in Thailand. The ferrocement tank consists of a lightly reinforced concrete base on which is erected a circular vertical cylinder with a 10 mm steel base. This cylinder is further wrapped in two layers of light wire mesh to form the frame of the tank. This tank has the potential for small/large scale production by artisans, very low maintenance; repairs can easily be carried out, low cost, suitable for many ground conditions and has good protection against mosquitoes. It however requires a certain high level of skill. This has also been practiced in Kyenjojo in Uganda. (DTU, 2000).

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Brick Jars The jar consists of a brick outer section; a waterproof internal render and a thin mortar cover with a filter basin. It has low manufacture time, low maintenance, repairs easily carried out and conducive for many ground conditions. However, the cost per litre storage is higher than the Plastic Tube Tank. In his work in Western Uganda, Thomas (1995) observed that iron roof is the most common in this area due to the high rainfall.

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The Thai jar The Thai jar programme is very much in practice at present. There are two types of Thai rainwater harvesting systems. The individual household jars and more community oriented tanks. Both are surface structures with jars varying in its capacity from 1.2 to 2.0 m3 and tanks from 7.5m3 to 10m3. Both these structures are widely seen in most rural areas in N‐E Thailand, though jars are more commonly used. Ferro‐cement jars are also in use at a few urban households. Private enterprises are into the manufacture of rainwater collection jars. Almost all people who collect rainwater use it exclusively for drinking and cooking. People prefer rainwater to other water due to its taste. As stated earlier Thai people in this part of the country has been using rainwater traditionally for

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domestic use including drinking. As such, quality of collected water is not a concern for these people. However, judging by the status of collection systems, nothing good is say about the quality of water. Water quality tests conducted during the early part of the programme under IDRC assistance, indicate bacteriological contamination of rain jars. However, the research also shows that contaminations from other sources of water are far greater than rainwater jars. For instance, traditional earthen jars and shallow ground water have indicated higher concentration of contamination than roof run off. (Ariyabandu, 2001). 2.3.4 Filtering Subsystem Dirt, debris, and other materials from the roof surface may contaminate the rainwater. The best strategy is to filter and screen out the contaminants before they enter the cistern. A leaf screen over the gutter and at the top of the downspout is helpful. A primary strategy is to reject the first wash of water over the roof. The first rainfall will clean away any contaminants and is achieved by using a ʺroof washer.ʺ The main function of the roof washer is to isolate and reject the first water that has fallen on the roof after rain has begun and then direct the rest of the water to the cistern. Ten gallons of rainfall per thousand square feet of roof area is considered an acceptable amount for washing. Roof washers are commercially available and afford reliability, durability, and minimal maintenance to this function. Roof washing is not needed for water used for irrigation purposes. However, pre filtering to keep out debris will reduce sediment buildup. A sand filter can also be used. (Sourcebook Harvested Rainwater, 1994) 2.3.5 Distribution Removing the water from the cistern can be achieved through gravity, if the cistern is sufficiently high enough, or by pumping. Most cases will require pumping the water into a pressure vessel similar to the method used to withdraw and pressurize water from a well (except a smaller pump can be used to pump from a cistern). A screened 1.25 inch foot valve inside the tank connected to an 1.25 inch outlet from the cistern approximately one foot above the bottom (to avoid any settled particles) will help maintain the prime on the pump. A float switch should be used to turn off the pump if the water level is too low. Another alternative is the use of a floating filter inside the cistern connected to a flexible water line. This approach withdraws the water from approximately one foot below the surface which is considered to be the most clear water in any body of water. The water that will be used for potable purposes can pass through

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an inline purification system or point of use water purification system. Other uses for the water do not need additional purification. (Sourcebook Harvested Rainwater, 1994)

Rainwater systems can further be classified by their reliability, which gives four types of user regimes: Occasional ‐ water is stored for only a few days in a small container. Suitable when there is a uniform rainfall pattern with very few days without rain and there is a reliable alternative water source nearby. Intermittent ‐ in situations with one long rainy season when all water demands are met by rainwater; however, during the dry season water is collected from non‐rainwater sources. Partial ‐ rainwater is used throughout the year but the ʹharvestʹ is not sufficient for all domestic demands. For instance, rainwater is used for drinking and cooking, while for other domestic uses (e.g. bathing and laundry) water from other sources is used. Full ‐ for the whole year, all water for all domestic purposes is rainwater. In such cases, there is usually no alternative water source other than rainwater, and the available water should be well managed, with enough storage to bridge the dry period. The type of user regimes to be followed depends on many variables including rainfall quantity, rainfall pattern (length of the rainy periods, the intensity of the rains), available surface area, available or affordable storage capacity, daily consumption rate, number of users, cost and affordability, presence of alternative water sources and the water management strategy. •

•

•

•

2.4 Water Quality of Rooftop Rainwater Harvesting Systems The raindrop as it falls from the cloud is soft, and is among the cleanest of water sources. Use of captured rainwater offers several advantages. Rainwater is sodium free, a benefit for persons on restricted sodium diets. Irrigation with captured rainwater promotes healthy plant growth. Also, being soft water, rainwater extends the life of appliances as it does not form scale or mineral deposits. The environment, the catchment surface, and the storage tanks affect the quality of harvested rainwater. The falling raindrop acquires slight acidity as it dissolves

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carbon dioxide and nitrogen. Contaminants captured by the rain from the catchment are of concern for those intending to use rainwater as their potable water source. The catchment area may have dust, dirt, fecal matter from birds and small animals, and plant debris such as leaves and twigs. Water quality of rooftop rainwater harvesting systems is an issue of increased interest particularly in developing countries where the collected water is used as a source of drinking water. Studies reported from different parts of the world reveal that the water quality is often suspected, especially in terms of its microbiological quality. Among various factors that affect the water quality of roof runoff, roof material, rainfall intensity, dry period preceding a rainfall event and proximity to pollution sources seem to determine the physicochemical quality of the collected rainwater. As for microbiological quality, roof material and any dry period could play a significant role in determining the quality. A few studies, however, show that well‐kept rainwater is a good quality source, usually within the WHO “low risk” category (Ariyananda & Mawatha 1999; Coombes et al. 2000; Vasudevan et al. 2001). Poor collection and maintenance practices will reduce the quality considerably. This indicates the need for proper design and maintenance strategies to minimise the contamination of potable roof‐collected rainwater supplies. All studies suggest that some form of treatment of the harvested rainwater is necessary before it can be used as a source of drinking water. More studies are needed to assess the microbial risk associated with the consumption of water from domestic rainwater harvesting systems. A few studies reported in the literature indicate that consumption of untreated rainwater is a definite risk to the health of consumers (Crabtree et al. 1996; Simmons et al. 1999, 2001; Lye 2002). Diseases attributed to the consumption of untreated rainwater include bacterial diarrhea, bacterial pneumonia, botulism, protozoal diarrhea, and diarrheas from Giardia and Cryptosporidium. Most of the studies reported on this aspect are from developed countries. There is a need to assess the health implications of the use of rooftop rainwater harvesting systems in developing countries, where the use of rainwater as a source of drinking water is becoming more widespread. There is also a need to develop some simple and rapid field‐testing methods for use in developing countries to indicate microbial contamination of drinking water. The H2S strip test based on the production of H2S by sulfate reducing bacteria appears to be promising in this regard (Vasudevan et al. 2001). A good correlation was observed between the results of conventional indicators of microbial pollution and the H2S strip test. However, more studies are needed to standardise the procedure. Further, more research is needed on how to improve the quality of rainwater collected from 21


roof catchments through improvements in design features and maintenance practices. The HACCP (hazard analysis and critical control point) approach, introduced by the WHO in its latest edition of Drinking‐Water Quality Guidelines (WHO 2003) is suitable for design, construction, management and operation of rooftop rainwater harvesting systems (Heijnen 2001). HACCP also allows an assessment of risks related to the use of different roof surfaces and fittings would help the public health authorities to develop their own strategies to improve the collected rainwater quality. With minimal treatment and adequate care of the system, however, rainfall can be used as potable water as well as for irrigation. The cleanliness of the roof in a rainwater harvesting system most directly affects the quality of the captured water. The cleaner the roof, the less strain is placed on the treatment equipment. It is advisable that overhanging branches be cut away both to avoid tree litter and to deny access to the roof by rodents and lizards. 2.6 Site and Rainwater Harvesting System Selection It is important when choosing a rainwater harvesting system to consider not only the physical aspects of the project but the socio and economic requirements of the community it is to serve. These may include the initial costs, the quality of the water, operation and maintenance requirements of the technique. The most important parameters to consider in identifying areas suitable for rainwater harvesting are as follows:

2.6.1 Rainfall The knowledge of rainfall characteristics (intensity and distribution) for a given area is one of the pre‐requisites for designing a rainwater harvesting system. The availability of rainfall data series in space and time and rainfall distribution is important for determination of amount of rainwater that can be harvested. Useful rainfall factors for the design of a rain‐ or floodwater harvesting system include: 1. Number of days in which the rain exceeds the threshold rainfall of the catchment, on a weekly or monthly basis, 2. Probability and occurrence (in years) for the mean monthly rainfall, 22


3. Probability and reoccurrence for the minimum and maximum monthly rainfall, 4. Frequency distribution of storms of different specific intensities 2.6.2 Hydrology and Water Resources The hydrological processes relevant to rainwater harvesting practices are those involved in the production, flow and storage of runoff from rainfall within a particular project area. The rain falling on a particular catchment area can be effective (as direct runoff ) or ineffective (as evaporation, deep percolation). The quantity of rainfall that produces runoff is a good indicator of the suitability of the area for rainwater harvesting. The other sources of water must be considered in designing of rainwater harvesting system. For instance, ground water source may need rainwater to recharge the aquifers and therefore harnessing all available runoff will affect it. 2.6.3 Socio Economic and Infrastructure Conditions ‐

The socio‐economic conditions of a region being considered for any rainwater harvesting scheme are very important for planning, designing and implementation. The chances for success are much greater if resource users and community groups are involved from early planning stage onwards. The financial capabilities of the average farmer, the cultural behaviour together with religious belief of the people, attitude of people towards the introduction of new technology, and the role of women and minorities in the communities are crucial issues. This is particularly important in the arid and semi‐arid regions of Africa and may help to explain the failure of so many projects that did not take into account the people’s priorities. For example in a West African study on water harvesting (Tauer & Humborg 1992), the distance between the suitable areas and the villages was regarded as an important criterion. It was assumed that farmers were willing to walk not more than 6 km from their homes if the proposed water harvesting system is acceptable to them. The existing or planned infrastructure as well as regional development plans has to be duly taken into account when planning a rainwater harvesting scheme (Siegert 1994).

2.6.4 Environmental and Ecological Impacts 23


Dry area ecosystems are generally fragile and have a limited capacity to adjust to change (Oweis et al. 1999). If the use of natural resources (land and water), is suddenly changed by water harvesting, the environmental consequences are often far greater than foreseen. Consideration should be given to the possible effect on natural wetlands as on other water users, both in terms of water quality and quantity. New water harvesting systems may intercept runoff at the upstream part of the catchment, thus depriving potential down stream users of their share of the resources. Water harvesting technology should be seen as one component of a regional water management improvement project. Components of such integrated plans should be the improvement of agronomic practices, including the use of good plant material, plant protection measures and soil fertility management (Oweis et al. 1999). 2.6.5 Costs The quantities of earth/stonework involved in construction directly affect the cost of a scheme.

2.7 Water Balance and System Sizing The basic rule for sizing any rainwater harvesting system is that the volume of water that can captured and stored (the supply) must equal or exceed the volume of water used (demand). The variables of rainfall and water demand determine the relationship between required catchment area and storage capacity. In some cases, it may be necessary to increase catchment surface area by addition of a barn or outbuilding to capture enough rainwater to meet demand. Cistern capacity must be sufficient to store enough water to see the system and its users through the longest expected interval without rain. Usually the main calculation when designing a DRWH system will be to size the water tank correctly to give adequate storage capacity. The storage requirement will be determined by a number of interrelated factors which include; •

Local rainfall and weather pattern

•

Roof or other collection area

•

Runoff coefficient (this varies between 0.5 and 0.9 depending on roof material and slope)

•

User number and consumption rates

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Rainfall data is required, preferably for a period of at least 10 years. The more reliable and specific the data is for the location the better the design will be. A figure for the average rainfall in a given area can be found at offices of the Department of Meteorological Services, Department of Agriculture or Water Resources, at airports and in the national atlas used in schools. Domestic water consumption and demand varies substantially by country. Socio‐ economic conditions and different uses of domestic water are among the influencing factors. Where water is very scarce, people may use as little as a few litres per day. 20 lcd is a commonly accepted minimum. An estimate of the amount of water required for economic and productive uses should be added. In general, roof rainwater harvesting is only able to provide sufficient water for a small vegetable plot. The style of rainwater will also play a part in determining the system components and their sizes. There are a number of different methods for sizing system components. These methods vary in complexity and sophistication. The choice of method used to design system components will depend largely on the following; 1. The size and sophistication of it’s components 2. The availability of the tools required for using a particular method (e.g. Computers) 3. The skills and education levels of the practitioner or designer As the cost of domestic rainwater harvesting system depends mainly on the size of the tank, it is important to design the tank to ensure optimum performance at tolerable cost. 2.7.1 Supply Calculation The volume of water (V) that can be harvested over a roof area (supply) is proportional to the amount of rain(R) falling over the roof area (A) is given by the formula: V (I) = R (mm) x A (m2) x CR whereby CR is the runoff coefficient. The runoff coefficient CR for corrugated metal sheet is 0.7 – 0.9 and for tiles is 0.8 – 0.9. 2.7.2 Demand Calculation The first decision in rainwater harvesting system design is the intended use of the water. If rainwater is intended to supply water during the then dry spells, 25


then the demand is calculated for the dry spells period. If the rainwater is intended to be the sole source of water for all indoor and outdoor domestic end uses, then annual consumptive demand is calculated. Water demands depend on the consumption rates and occupancy of the building. Dry Spells Demand = Consumption per capita per day, C x Number of people per household, n x Longest average dry period, t Annual Consumption Demand, D = Consumption per capita per day, C x Number of people per household, n x 365 2.7.3 Storage Capacity Calculation Rainfall occurs seasonally, requiring a storage capacity sufficient to store water collected during rainy times to last through the dry spells. Below outline three different methods for sizing RWH system components. Method 1 demand side approach ‐

A very simple method is to calculate the largest storage requirement based on the consumption rates and occupancy of the building. Typical data needed to estimate the tank size are; •

•

•

Consumption per capita per day, C Number of people per household, n Longest average dry period, t

Annual consumption, D = C x n x 365 = A litres Storage requirement, T = (Annual consumption, D x dry period, t) / 365 = B litres This simple method assumes sufficient rainfall and catchment area that is adequate, and is therefore only applicable in areas where this is the situation. It is a method for acquiring rough estimates of tank size. Another simple method of roughly estimating storage capacity popular among professional installers is to size the storage capacity to meet quarterly demand. The system is sized to meet estimated demand for a three –month period without

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rain. Annual demand is divided by four to yield necessary storage capacity using this approach. Method 2 supply side approach ‐

Rainwater supply depends on the annual rainfall, the roof surface area and the runoff coefficient. Supply = Annual Rainfall (mm/year) x area (m2) x Runoff coefficient To ensure a year‐round water supply, the catchment area and the storage capacity must be sized to meet water demand through the longest expected interval without rain. In this approach, the storage capacity is determined based on the water that can be harvested. Method 3 – computer model Special software for tank sizing called SIM‐TANKA has been developed (www. geocities.com/Rainforest/canopy/4805). It requires at least 15 years of monthly rainfall records for the place of which the rainfall harvesting system is located. If that is not available then that of the nearest place that has the same pattern of rainfall can be used. The included utility rain recorder is used for entering the rainfall data. Daily consumption per person is also entered and then the software will calculate optimum storage size or catchment size depending on the requirement of the user.

2.8 Potential Effects and Impacts – Taking a Livelihoods Based Approach ‐

The impacts of rooftop rainwater harvesting will be greatest where it is implemented as part of wider strategies that take as a starting point people’s overall livelihood strategies. In this context, water should be seen as a key productive as well as domestic resource, with different uses being made of it by men and women. The flexibility of rainwater harvesting gives room for innovation. For example, there can arise an interrelation of variety of both economic and social activities that can improve living standards. The main idea starts from intercepting rainwater as a hydrological cycle component and diverting it to food/feed production including processing, marketing and compost sourcing/recycling. This is a holistic approach of interactions of many profitable activities originating from a controlled water source. From one 27


rainwater harvesting storage structure can arise a myriad of interrelated activities including kitchen gardens, poultry keeping, zero grazing, biogas digester installations, manure harvesting, drip irrigation for horticultural crops production and fish farming among other economic activities. All these activities have a projection on increased income generation, improved nutrition status, improved sanitation and personal hygiene, creation of on‐farm employment leading to poverty reduction and conservation of the environment. (Gould, 1999) The impacts of roof water harvesting taking a livelihood approach would be as follows;

2.8.1 Reduction of Burdens of the Poor Women and female children spend more than 200 million hours each day to collect water from distant, often‐polluted sources. The most important impact in terms of women and the poor is the reduction in time spent collecting water, which can be as much as several hours per day. This time then becomes available for other purposes, both productive and ‘social’; more time to spend with children, friends, etc. 2.8.2 Health Impacts Rainwater is often used for drinking and cooking and so it is vital that the highest possible standards are met. Rainwater, unfortunately, often does not meet the World Health Organisation (WHO) water quality guidelines. This does not mean that the water is unsafe to drink. Gould and Nissen ‐Peterson (1999), in their recent book, point out that the Australian government have given the all clear for the consumption of rainwater ‘provided the rainwater is clear, has little taste or smell, and is from a well‐maintained system’. It has been found that a favourable user perception of rainwater quality (not necessarily perfect water quality) makes an enormous difference to the acceptance of RWH as a water supply option. Generally, the chemical quality of rainwater will fall within the WHO guidelines and rarely presents problems. There are two main issues when looking at the quality and health aspects of DRWH: Firstly, there is the issue of bacteriological water quality. Rainwater can become contaminated by faeces entering the tank from the catchment area. It is advised that the catchment surface always be kept clean. Rainwater tanks should be designed to protect the water from contamination by leaves, dust, insects, vermin, and other industrial or agricultural pollutants. Tanks should be sited away from 28


trees, with good fitting lids and kept in good condition. Incoming water should be filtered or screened, or allowed to settle to take out foreign matter. Water that is relatively clean on entry to the tank will usually improve in quality if allowed to sit for some time inside the tank. Bacteria entering the tank will die off rapidly if the water is relatively clean. Algae will grow inside a tank if sufficient sunlight is available for photosynthesis. Keeping a tank dark and sited in a shady spot will prevent algae growth and also keep the water cool. The dirty first flush water must always be diverted away from the storage tank. The area surrounding a RWH should be kept in good sanitary condition, fenced off to prevent animals fouling the area or children playing around the tank. Any pools of water gathering around the tank should be drained and filled. Gould points out that in a study carried out in northeast Thailand 90 per cent of in‐house storage jars were contaminated whilst only 40% of the RWH jars were contaminated. This suggests secondary contamination (through poor hygiene) is a major cause of concern. Secondly, there is a need to prevent insect vectors from breeding inside the tank. In areas where malaria is present, providing water tanks without any care for preventing insect breeding, can cause more problems than it solves. All tanks should be sealed to prevent insects from entering. Mosquito proof screens should be fitted to all openings. Some practitioners recommend the use of 1 to 2 teaspoons of household kerosene in a tank of water which provides a film to prevent mosquitoes settling on the water. There are several simple methods of treatment for water before drinking. 1. Boiling water will kill any harmful bacteria which may be present 2. Adding chlorine in the right quantity (35ml of sodium hypochlorite per 1000 litres of water) will disinfect the water 3. Slow sand filtration will remove any harmful organisms when carried out properly 4. A recently developed technique called SODIS (SOlar DISinfection) utilises plastic bottles which are filled with water and placed in the sun for one full day. The back of the bottle is painted black However, rainwater is usually a considerable improvement over unprotected traditional sources and stored rainwater maintains a good water quality provided the tank is well maintained. Direct and indirect health impacts include: 1. Water‐related illnesses are reduced because of the use of cleaner and safer rainwater (although household‐ based treatment is recommended), particularly compared to water from surface sources. This results in less sick days, increased economic activities, and savings in medical expenses.

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2. Malnutrition may reduce as rainwater used for vegetable and other crop growing contributes to an improved diet. 3. Improved sanitation and hygiene resulting from increased availability of water can also add to improved health. 4. Reduced transportation of heavy loads over long distances from an early age leads to reduced back problems and growth reduction 5. Increased income streams from productive uses of additional water can in turn lead improved nutritional status and a reduction in communicable diseases due to improved home environmental conditions (better housing, ventilation etc.) 2.8.3 Economic Impacts Direct economic impacts will come almost entirely from the use of water for economic activities. Apart from the environmental gains, there is an economic advantage to the harvesting and use of rainwater, most notably in the commercial sector as the service providers continue to increase charges. Farms, horticultural establishments, public buildings such as schools and visitor centres, public housing, petrol stations (using water for vehicle washing) could all gain an economic advantage by using harvested rainwater and stop using treated water for non drinkable uses. This may lead to significant poverty alleviation leading to improved living conditions as many RWH initiatives have shown. 1. Productive use of rainwater for vegetable gardening (small scale irrigation), 2. Productive use of rainwater for home‐ based economic activities such as beer brewing, brick making, oil making etc and 3. Income generating activities may also be the result of the utilization of time saved in collection of domestic water. 2.8.4 Poverty Alleviation Direct and indirect capacity building, (skill development, knowledge building, access to information), reduction of vulnerability, strengthening of social and physical infrastructure, all help to alleviate poverty. During mobilization (e.g. in PRAs etc.) issues such as injustice, isolation from existing institutions and supplies are analyzed and can be specifically addressed. Children and particularly young girls may be deprived of education due to the need to assist their mothers in collecting water from far‐away sources. The time

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saving in collection from the close to home source will allow them to attend school. 2.8.5 Environmental Benefits Rainwater harvesting promotes independence and self‐sufficiency and also help to develop an appreciation for this precious and finite resource. This activity conserves water and also energy input to treat and pump water over a vast service area for a centralised water system. Aside from conserving water use, it also minimises local erosion and flooding due to runoff from impervious areas such as pavement and roofs and decreases storm water run‐off which picks‐up contaminants and degrades drains, streams, rivers and seas. Since 58% of rainfall in Malaysia ends up as surface runoff, there is a strong case to employ systems such as RWHS to put an end to such wasted resources.

2.8.6 Domestic and Industrial Benefits The exceptional quality of rainwater has made it a viable water resource supplement. Rainwater quality often exceeds that of ground or surface water, as it does not come into contact with soil, dissolving salts and minerals in the process. It is not subject to pollutants found in rivers. Rainwater has hardness approaching zero thereby reducing significantly the quantity of detergents and soaps needed for cleaning, as compared to typical piped water. There is virtually no soap scum and hardness deposits thus eliminate the need for a water softener, which is expensive for well water systems. Water heaters and pipes will be free of deposits caused by hard water and this can prolong their service lifetime. 2.9 Planning and Management of Rainwater Harvesting System Domestic rainwater harvesting needs to be seen as only part of a system to meet the overall water requirements of a household or community. Project planning must take a people ‐centred approach taking socio‐economic, cultural, institutional, and gender issues into account, as well as people ʹs perceptions, preferences and abilities. Factors for success in DRWH are: 1. project starts small and grows slowly to allow for testing and modification of design and implementation strategy;

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2. demand for water is clearly expressed; 3. full involvement of both sexes in all project stages; and 4. substantial contributions from the people in ideas, funds and labour. In a number of countries (e.g. Kenya, Fiji) womenʹs groups have been very successful in financing and building their own RWH tanks. Management by individual households is most successful. This is because the user (often a woman) operates and controls the system, is responsible for its maintenance, manages the use of water (minimum misuse), and appreciates the convenience of water next to her home. Rainwater is managed in a number of ways. The main management strategies are listed below. Maximum Security The water from the tank is not utilized until all the possible water sources are completely depleted. In this case, in the rainy season after the tank has been filled, it is locked up. This has a disadvantage of not maximizing the water from the roofs, thus the tank is left to overflow. Maximum Capture The tank is used as a water source throughout the rainy season. It keeps filling as the stored water is being utilized. However, there is a tendency of reducing the daily consumption as the dry season sets in.

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CHAPTER THREE CASE STUDY OF GHANA

General Background Ghana lies in the center of the West African coast, shares borders with the three French‐speaking nations of Côte dʹIvoire to the west, Togo to the east, and Burkina Faso (Burkina, formerly Upper Volta) to the north. To the south are the Gulf of Guinea and the Atlantic Ocean. With a total area of 238,533 square kilometers, Ghana is about the size of Britain. Its southernmost coast at Cape Three Points is 4° 30ʹ north of the equator. From here, the country extends inland for some 670 kilometers to about 11° north. The distance across the widest part, between longitude 1° 12ʹ east and longitude 3° 15ʹ west, measures about 560 kilometers. The Greenwich Meridian, which passes through London, also traverses the eastern part of Ghana at Tema The climate of Ghana is tropical, but temperatures vary with season and elevation. Except in the north two rainy seasons occur, from April to July and from September to November. In the north, the rainy season begins in April and lasts until September. Annual rainfall ranges from about 1,100 mm (about 43 in) in the north to about 2,100 mm (about 83 in) in the southeast. The harmattan, a dry desert wind, blows from the northeast from December to March, lowering the humidity and creating hot days and cool nights in the north. In the south the effects of the harmattan are felt in January. In most areas the highest temperatures occur in March, the lowest in August. Ghana is a lowland country, except for a range of hills on the eastern border. The sandy coastline is backed by a coastal plain that is crossed by several rivers and streams, generally navigable only by canoe. In the west, heavily forested hills and many streams and rivers break the terrain. To the north lies an undulating savanna country that is drained by the Black and White Volta rivers, which join to form the Volta, which then flows south to the sea through a narrow gap in the hills. Much of the natural vegetation of Ghana has been destroyed by land clearing for agriculture, but such trees as the giant silk cotton, African mahogany, and cedar are still prevalent in the tropical forest zone of the south. The northern two‐thirds of the country is covered by savanna ‐a grassland with scattered trees. Animal life has also been depleted, especially in the south, but it remains relatively diverse and includes leopard, hyena, buffalo, elephant, wildhog, antelope, and monkey. Many species of reptiles are found, including the cobra, python, puff adder, and horned adder. Agriculture is Ghanaʹs most important economic sector,

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employing more than half the population on a formal and informal basis and accounting for almost half of GDP and export earnings. The country produces a variety of crops in various climatic zones which range from dry savanna to wet forest and which run in eastwest bands across the country. Agricultural crops, including yams, grains, cocoa, oil palms, kola nuts, and timber, form the base of Ghanaʹs economy. Background on Northern Region Location and size The Northern Region, which occupies an area of about 70,383 square kilometres, is the largest region in Ghana in terms of land area. It shares boundaries with the Upper East and the Upper West Regions to the north, the Brong Ahafo and the Volta Regions to the south, and two neighbouring countries, the Republic of Togo to the east, and La Cote d’ Ivoire to the west. The region is divided into eighteen (18) districts. These are Bole, Bunkpurugu ‐Yungoo, Central Gonja, East Gonja, East Mamprusi, Gushiegu, Nanumba North, Nanumba South , Saboba/ Chereponi, Saveugu/ Nanton, Sawla‐Tuna‐Kalba, Temale Metropolitan, Tolon/Gumbungu, West Gonja, West Mamprusi , Yendi and Zabzugu. The land is mostly low lying except in the north‐eastern corner with the Gambaga escarpment and along the western corridor. The region is drained by the Black and white Volta and their tributaries, Rivers Nasia, Daka, etc. Climate and vegetation The climate of the region is relatively dry, with a single rainy season that begins in May and ends in October. The amount of rainfall recorded annually varies between 750 mm and 1050 mm. The dry season starts in November and ends in March/April with maximum temperatures occurring towards the end of the dry season (March‐April) and minimum temperatures in December and January. The harmattan winds, which occur during the months of December to early February, have considerable effect on the temperatures in the region, which may vary between 14°C at night and 40°C during the day. Humidity, however, which is very low, mitigates the effect of the daytime heat. The rather harsh climatic condition makes the cerebrospinal meningitis thrive, almost too endemic proportions, and adversely affects economic activity in the region. The region also falls in the onchocerciasis zone, but even though the disease is currently under control, the vast area is still under populated and under cultivated.

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The main vegetation is classified as vast areas of grassland, interspersed with the guinea savannah woodland, characterised by drought‐resistant trees such as the acacia, baobab, shea nut, dawadawa, mango, neem. Demographic characteristics The population of the region is 1,820,806, representing 9.6 per cent of the country’s population. This translates into a growth rate of 2.8 per cent over the 1984 population of 1,162,645. This rate of growth is much lower than that of 3.4 per cent recorded between 1970 and 1984. Economic activities Agriculture, hunting, and forestry are the main economic activities in the region. Together, they account for the employment of 71.2 per cent of the economically active population, aged 15 years and older. Less than a tenth (7.0%) of the economically active people in the region are unemployed. Main source of drinking water The commonest sources of drinking water in the region are the rain, spring, river and stream (27.2%). About a fifth of households (19.6%) use dugouts for the collection of rainwater, followed by pipe borne water in the form of a standpipe, either inside or outside the house (22.4%) and borehole (17.0%). Other sources, constituting mainly tanker supply, represent only about 1.0 per cent of household water sources. This means that only 39.4 per cent of households have access to potable water (pipe‐ borne plus borehole); this has implications for water borne diseases for the region. At the district level, the proportion of households with piped water varies from 0.9 per cent in East Mamprusi District, to 78.9 per cent in Tamale municipality. In most of the districts, the main sources of water are wells, dugouts or rainwater/rain/river/stream. The dependence on these sources of water has major implications for the health of the population. Contaminations during the process of collection may aggravate the incidence of diarrhoea and other water borne diseases. The use of the tanker supply, an important source of household water, is only prevalent in Tamale where it accounts for about 4.0 per cent of the water supply of households.

1. Background on East Gonja District (Northern Region)

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The East Gonja District is the second largest district in the Northern region. It shares borders with the Yendi and Tamale Districts to the north, West Gonja District to the West, Nanumba district of Brong‐Ahafo and Volta Regions respectively to the south. It occupies an area of about 10, 787 square kilometers. Topology and Drainage: The topography of the district is typical of the Northern Region, generally flat with few undulating surfaces. Nowhere does the land rise up to 200 metres. The district is underlain by the Voltarian sedimentary formation with low potential for mineral formations and poor water retention. The area receives annual precipitation averaging 1,050mm, considered enough for single farming season. Temperatures are usually high, averaging 300C. The main drainage system in the district is made up of the Volta and some of its major tributaries including the White Volta, the Daker and Oti Rivers. There is a good flow of water which is collected and stored in the Volta Lake. Potential exists for irrigation and small dam sites. The natural vegetation in the district is Guinea Savannah Woodland, which consists of trees that are drought resistant. Most of these trees are of economic value. Notable amongst them are the shea and dawadawa trees. Compared to the rest of the Northern Region, the tree cover is dense although intense harvesting for fuel wood is fast reducing the natural flora. At the extreme south‐east, the vegetation is dense and semi‐deciduous trees such as oil palm trees, raffia palms and others can be found. There are three major groups of soils in the district: Alluvial Soils, Ground water Laterites and Savannah Ochrosols. Economic Activities East Gonja district’s economy is purely rural, dominated by agriculture, which, include fishing and forestry, accounts for 76% of total employment. Agriculture in the East Gonja District is dominated by crop farming, which provides the main farm income. The district is a major producer of maize, rice cassava, yam and sorghum. Livestock (cattle, goats, sheep and pigs) are kept but not as part of mixed farming system. Inland fishing is a major source of activity in the district particularly

36


along the Volta Lake and its tributaries. Manufacturing accounts for about 6.5% of the labour force. Pito brewing dominates in the area of food and beverage processing; and textile manufacturing, involving small‐scale informal sector artisans is the other major manufacturing activity. Commerce employs about 15% of the total labour force, mostly in the area of retail trading. There are 14 markets located in the district, where, in the main agricultural produce is sold.

Background on West Mamprusi District (Northern Region) The West Mamprusi District is one of 45 new districts created in 1988 under the Government of Ghana’s decentralization and local government reform policy. Carved out of the old Gambaga District in the Northern Region. The district capital is Walewale, which lies on the Tamale‐Bolgatanga trunk road, approximately 68 miles away from Tamale. The district is bordered to the north by Builsa, Kassena ‐Nankana and Bolgatanga districts, in the Upper East Region; to the south west by Gonja, Tolon‐Kumbungu and Savelugu district in the Northern Region; to the west by the Sissala and Wa districts; and to the east by East Mamprusi and Gushiegu ‐Karaga Districts. Location and Size The West Mamprusi District has an area of about 5,013 square kilometers. Topology and Drainage Major rivers that drain the district are the Kulpawn, White Volta and Nasia. Climate and Vegetation The area lies in the Guinea Savannah zone. Consequently, the vegetation comprises short tress, grasses and shrubs. Economic Activities

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Agriculture is the major economic activity in the district. Crops produced in the district are maize, rice, millet, sorghum, groundnuts, beans, yams, cotton and soyabean. Livestock production is another activity in the district with a lot of economic potential. The fairly flat land coupled with the availability of grasses in most parts of the district provides an ideal environment for livestock and poultry rearing. Animals reared include cattle, sheep‐goats, pig and birds. Importantly, there is little or no incidence of tsetsefly in most areas of the district, a further advantage for livestock farmers. The presence of large water bodies also creates a lot of potential for irrigation in the district in the dry season for production of crops. Tomatoes, pepper, soya beans, onions, vegetables and tobacco among others are cultivated along the banks of the main river draining the district, the White Volta. The development of irrigation further from the rivers would greatly enhance agricultural productivity for large scale farmers. 3. Background on Nanumba District (Northern Region) Nanumba North District is located at the eastern part of the Northern Region of Ghana. The district shares boundaries with East Gonja District to the west and south‐west, and Yendi District to the north. To the east, it shares boundaries with Zabzugu/Tatali District and the Republic of Togo, and to the south east with the Volta Region. The district capital is Bimbilla. Location and Size The district has area of about 3,220 square kilometers. Topology and Drainage The main drainage features of the district are River Oti and Dakar. The Oti River has about 85km of its stretch meandering from north to south through the district, while the Dakar River spans 145km of the western boundary with East Gonja District. Other drainage features include Kumbo and Kumar streams, dams and dug‐outs, and Jual Gorge designated as a hydroelectric site on the Oti River. Climate and Vegetation The district lies in the Tropical Continental Climate Zone with the mid‐day sun always overhead. As a result, temperatures are fairly high ranging from 29

38


degrees celsius to 41 degress celsius. Its vegetation type is the Guinea Savannah with tall grass interspersed with drought and fire‐resistant trees. Tree species found are the dawadawa, sheanut, baobab and other fire‐ resistant trees. Geology and Soil Soil types are the Savannah Ochrosols. Savannah Ochrosols are of alluvial ‐ colluvial origin found mainly along major rivers and drainage courses and are located mid‐south through to the north. They are medium textured material, moderately well drained soils suited for a wide range of crops such as cereals, roots and tubers, and legumes. The savannah Ochrosols are well drained soils with the surface having loamy sand or sand‐textured material with good water retention. In the district, these soils are located to the east of the Oti River and the south‐west through to the north. Ground water laterites are shallow sandy or loamy soils composed of rock fragments found on the summits of upland areas. They are suitable for forestry and conservation programmes. The district soils are characteristically heavy and dark coloured. Economic Activities Agriculture is the major economic activity in the district. The soils are suitable for the cultivation of cereals such as rice, sorghum, millet and maize. They are also well suited for legumes, such as cowpea, soyabeans, groundnuts, and bambara beans. The women are involved in the production of oils from groundnut, soya and shea nuts. 4. Background on Yendi District (Northern Region) The Yendi District cut through by the Greenwich Meridian, which passes through a number of settlements in the district. The district shares boundaries with seven other district; to the east, with Saboba/Chereponi and Zabzugu/Tatale, to the south, with Nanumba and East Gonja, to the west, with Tamale and Savelugu and to the north, with Gushiegu/karaga districts. It has an area of about 5,350 square kilometres Economic Activities

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Majority of the people are employed in the Agricultural sector. The major crops grown in the district are maize, rice, sorghum, millet, cassava, yam, groundnut and beans, all of which are outstandingly productive in the area Instructively, the Ministry of Food and Agriculture estimates that the yields per hectare for these crops in Yendi District are all higher than the averages for the whole of the Northern Region. Background on Upper East Region Physical features Upper East is located in the north‐eastern corner of the country between longitude 00 and 10 West and latitudes 100 30”N and 110N. It is bordered to the north by Burkina Faso, the east by the Republic of Togo, the west by Sissala in Upper West and the south by West Mamprusi in Northern Region. The land is relatively flat with a few hills to the East and southeast. The total land area is about 8,842 sq km, which translates into 2.7 per cent of the total land area of the country. Upper East region has eight districts namely: Bawku Municipal, Bawku West, Bolgatanga Municipal, Bongo, Builsa, Garu‐Tempane, Kassena/Nankana and Nabdam. Soil and Drainage The region’s soil is “upland soil” mainly developed from granite rocks. It is shallow and low in soil fertility, weak with low organic matter content, and predominantly coarse textured. Erosion is a problem. Valley areas have soils ranging from sandy candy loams to salty clays. They have higher natural fertility but are more difficult to till and are prone to seasonal waterlogging and floods. Drainage is mainly by the White and Red Volta and Sissili Rivers (Regional Coordinating Unit, 2003). Climate and Vegetation The climate is characterized by one rainy season from May/June to September/October. The mean annual rainfall during this period is between 800 mm and 1.100 mm. The rainfall is erratic spatially and in duration. There is a long spell of dry season from November to mid February, characterized by cold, dry and dusty harmattan winds. Temperatures during this period can be as low

40


as 14 degrees centigrade at night, but can go to more than 35 degrees centigrade during the daytime. Humidity however, very low making the daytime high temperature less uncomfortable. The region is entirely within the “Meningitis Belt” of Africa. It is also within the onchocerciasis zone, but with the control of the disease, large areas of previously abandoned farmlands have been declared suitable for settlement and farming. The natural vegetation is that of the savannah woodland characterised by short scattered drought‐resistant trees and grass that gets burnt by bushfire or scorched by the sun during the long dry season. Human interference with ecology is significant, resulting in near semi‐arid conditions. The most common economic trees are the sheanut, dawadawa, boabab and acacia. Water Supply About 51 per cent of the region’s population have access to potable drinking water. Ghana Water Company Limited (GWCL) supplies pipe‐ born water to Bolgatanga, Chuchuliga, Zebilla, Bawku, Sandema, Navrongo, Bongo and Paga. Almost two thousand (1,627) hand pumps (boreholes) and a number of hand‐ dug wells serve a majority of the rural populations. While water treated for consumption in Bolgatanga is from the Vea Dam, the pipe‐ born water systems in the other townships Housing The majority of the people live in huts built of mud and roofed with straw or zinc. The main features of the predominantly traditional architecture are round huts with flat roofs and small windows with poor ventilation.

Economic Activities Agriculture, hunting and forestry are the main economic activities in the region. About eighty per cent of the economically active population engages in

41


agriculture. The main produces are millet, guinea ‐corn, maize, groundnut, beans, sorghum and dry season tomatoes and onions. Livestock and poultry production are also important. There are two main irrigation projects, the Vea Project in Bolgatanga covering 850 hectares and the Tono Project in Navrongo covering 2,490 hectares. Altogether, they provide employment to about 6,000 small‐scale farmers. Other water‐retaining structures (dams and dugouts) provide water for both domestic and agricultural purposes. The region is also known for its handicrafts and a locally brewed beer known as Pito. 1. Background on Bawku Municipal/ East District (Upper East Region) The Bawku Municipal shares boundaries with the Republic of Burkina Faso to the north, Togo to the north‐east, East Mamprusi District of the Northern Region to the south and Bawku West District to the west. Location and size The district has an area of about 2067 square kilometres Topology and Drainage: Generally, the district has a low topography with the popular Zawse/Yarigungu Agol and Kugri Hills range rising between 1000 and 2000 feet. The White Volta River and its tributaries run into the district from Burkina Faso and Togo. Climate and Vegetation The climate is tropical and the vegetation is savannah, characterized with short trees, mostly nim, shea and mahogany. Geology and Soil The soils are sandy clay loams and alluvial sandy loms with interspersed gravel and rocks which are commonly used for building homes and construction work on roads. Economic Activities Agriculture is the major economic activity in the district. The staple foodstuffs of the Bawku East District include millet, rice, red and white sorghum, groundnut, 42


ginea corn, maize and Bambara Beans. About 90% of the food produced at subsistence level is consumed locally while onions and malts are transported down south for sale. Cotton, sheanuts and sweet potatoes are the cash crops produced in the District. Livestock production is also on the increase. The Bawku East District is noted for the production of high quality smocks, shea butter, groundnut oil, earthweare products and dawadawa. Women are the main producers of these items and they are financed through loans from the Employment and Income Generation Fund of the Dsitrict Assembly, the Bawku East Women Development Association, ACTION AID, (a British NGO), Agricultural Development Bank and the Bawku East Small Scale Farmers Association Rural Banks. Others are engaged in the pottery business. Clay pits, which, for ages, have been the source of material for earthenware production, are sited in several places around the district, as well as special colour pits of soil; red, black and white products, at Goobok near Zabgu. 2. Background on Kasenna Nankana District (Upper East Region) Kassena Nankana District, one of the eight districts in the Upper East Region is located in the northern part of Ghana. It is bordered by the Republic of Burkina Faso, and the Bolgatanga, Bonga, Builsa, Sissala and Mamprusi West Districts. It stretches for 55 kilometres from north to south and 53 kilometres from east to west. The district capital is Navrongo. It has an area of about 1,674 square kilometres. Topology and Drainage The topography is low‐lying with an average height of 100 metres above sea level. The terrain is undulating with isolated hills dotting the landscape. Climate and Vegetation The vegetation of the district is of the Sudan and savannah type with grassland separating deciduous trees. Geology and Soil The geology of the district comprises granite and shale, althouth the rock formations are actually of a diverse nature.

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Economic Activities Agriculture is the main economic activity in the district, employing nearly 68% of the population. The main occupations include farming on subsistence levels in crop production, livestock rearing and fishing. Other areas which offer employment opportunities to the populace include public service, retail / wholesale trade, food processing, textile and leather works, in that order of importance. The main crops grown through irrigation are rice, maize, tomatoes, and millet, sorghum and soya beans.

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Appraisal of village water systems and household water use We assessed the water needs of households, existing rainwater harvesting and storage systems, and potential for income generation using stored rainwater in 300 households in six Districts. Households in two communities in each of six Districts were surveyed for information on existing water resources, and water use patterns. Water resources The results indicate that source of water for domestic needs vary significantly between Districts in the two regions surveyed. In general, boreholes supply approximately 47 % of water for a household’s needs in Northern Ghana. Wells provide a 25 % of the surveyed group whilst dugouts and dams provided for almost the same proportion of the surveyed sample (Table 3). The data indicate that a larger proportion of households in the Upper East Region rely on boreholes. The average distance from a household to the most reliable community water source vary from 0.3 km in the East Mamprusi District to 8.0 km in the East Gonja District.

Type of reservoirs In communities where water resources appear adequate, households spend time and energy to fetch water because of inadequate containers/reservoirs in the house. The survey revealed that the predominant water storage reservoir in the households is clay pots. Only 12 out of 300 households indicated they do not use clay pots. These households use large (200 litres) metal drums and aluminium pots. The metal drums were found in Nanumba, Yendi and Mamprusi districts.

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Table: Sources of domestic water for households in six Districts in Northern Ghana. Percentages in parenthesis. District

Region

Bawku East Kassena ‐ Nankana East Gonja

Upper East Upper East Northern

Bore hole 36 (72.0)

Dam

Dugout Stream Well

Total

3 (6.0)

4 (8.0)

1 (2.0)

6 (12.0)

50

50 (100.0) 0

0

0

0

0

50

1 (2.0)

0

0

0(0)

0(0)

10 (20.0) 45 (90.0) 15 (30.0) 0 (0)

50

5 (10.0)

39 (78.0) 0

76 (25.3)

300 (100)

West Mamprusi Nanumba

Northern Northern

35 (70.0)

0(0)

Yendi

Northern

15 (30.0)

35 0 (0) (70.0) 39(13.0) 43 (14.3)

Total

‐

141 (47.0)

0

0 (0) 1 (0.3)

50 50 50

Capacity of water reservoirs and household water use Responses were obtained from 243 households on capacity of their reservoirs. Approximately 57 % of the households indicated they could store up to 250 litres at a time (table 4). A further 27% can store between 250 and 500 litres. Ten percent of the respondents indicated they have reservoirs to store water between 500 and 1000 litres. The data did not indicate any tendency towards large households having higher storage capacity. Most households, according to the ranges in figure 3, have capacities below 400 litres. The average storage capacity per household was estimated at about 360 litres.

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Table: Volume of household water reservoirs in six Districts in Northern Ghana Volume (ranges) of reservoirs (litres) 1 – 250 251‐500 501 ‐ 750 751‐1000 1001‐1250 1251‐1500 1501 ‐1750 1751‐2000 2001‐2250 2251‐2500 2501‐2750 2751‐3000 3001‐3250 Total

No. of households 139 65 14 10 1 3 5 1 0 1 1 2 1 243

% of households 57.20 26.75 5.76 4.12 0.41 1.23 2.06 0.41 0 0.41 0.41 0.82 0.41 100

60 ) s e r t i l 50 ( a t i p 40 a c ) r l e ( a p t i 30 y p t i a c c a p 20 a c e g 10 a r o t S

0 1-5

6-10

11-15

16-20

21-25

26-30

31-35

36-40

41-45

46-50

56-60

66-70

90-93

Number of household members

Fig 3. Estimate d storag e c ap ac ity pe r ca pita in househo lds of different sizes

The size of households varies from 4.3 to 93, and the majority of households (64 %) comprise 6‐15 members. Water usage per day per head is 30 litres, although with very large households (60‐90 members) per capita usage is much lower.

47


This decrease in water use per head for larger households is associated with a disproportionately larger number of children in larger households. In general usage per household during the wet season was found to be similar as in the dry season. Periods of household water shortage Responses from the survey indicate that most households experience severe water shortage for domestic and livestock needs from March to May (Fig. 4). Few of the respondents mentioned July and August, which are in the middle of the rainy season. Only few people also indicated January, which is a month during which the harmattan is severe. A small number of respondents (5.7 %) indicated that they do not experience any water problems. 30

25

20

s t n e d n o p 15 s e r f o %

10

5

0 January

February

March

April

May

June

July

August

Month of severest water stress

Fig 4. Period of severe water shortage in households as indicated b y ho useh old s in six d istric ts in Northe rn Gha na

The ability of a household to mitigate water shortages during the dry season depend mainly on the volume of reservoirs available for water storage, and the number of household members available to fetch water from a water source. The data from the survey showed that the households with reservoir volumes less than 251 litres are those who form the bulk of those who indicated earlier and longer periods of severe water shortage (Table 5). Households in this category comprise 46.6%, 71.6%, 61.9% 40.5% and 48.1% of the total number of households experiencing severe water shortage for the months of February, March, April, May and June, respectively.

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Table. Water storage reservoir capacity of households in relation to months of severe water shortage in Northern Ghana. Household storage capacity (litres) Up to 250 250 to 500 500 to 7500 750 to 1000 1000 to 1250 1250 to 1500 1500 to 1750 1750 to 2000 2000 to 2250 2250 to 2500 2500 ‐ 2750 2750 to 3000 3000 to 3250

1.1.1

Jan

Feb

Mar

Apr il

Ma y

Jun e

July

Aug Nil

Tota l

0 1 1 0 0 0 0 0 0 0 0 0 0 2

7 5 2 1 0 0 0 0 0 0 0 0 0 15

53 15 2 2 0 1 0 0 0 1 0 0 0 74

39 11 3 2 1 2 3 0 1 0 0 1 0 63

15 16 1 2 0 0 1 0 0 0 1 1 0 37

13 10 2 2 0 0 0 0 0 0 0 0 0 27

1 0 0 0 0 0 0 0 0 0 0 0 0 1

1 0 0 0 0 0 0 0 0 0 0 0 0 1

139 65 14 10 1 3 5 0 1 1 1 2 1 243

3.2.1.5.

5 5 2 1 0 0 0 0 0 0 0 0 1 14

Household acquisition of water

In Northern Ghana, the burden of water acquisition for a household rests on the women and children. The number of men who fetch water from village reservoirs for (domestic use) is 0.7 (or 1 man) per household , ranging from zero to a maximum of seven (Table 9). On the average, four women undertake this activity, but depending on the size of the household it ranges from 1 to 36. Men are most active in this respect in the Districts in the Upper East Region (Kassena ‐Nankana and Bawku East) and least active in the Northern Region. In 207 of the households surveyed (representing 69%) men are not involved in fetching water during the wet season. The corresponding figure for the dry season is 45.6% (Table 10). Only 2 households (0.7%) indicated that women are not involved in fetching water during the dry season.

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Table. Percent of household members in six Districts in Northern Ghana that undertake trips to fetch water for a household District Bawku East East Gonja Kassena ‐Nankana West Mamprusi Nanumba Yendi Total

Males (n=299) Mean Minimum Maximum 0.7 0 7 0.3 0 7 1.4 0 7 1.0 0 6 0.1 0 4 0.4 0 4 0.7 0 7

Females (n=294) Mean Minimum 4.1 1 3.4 1 2.9 1 5.5 1 4.1 1 3.5 1 3.9 1

Maximu 15 11 10 36 24 10 36

n represents number of households surveyed

Table 10. Percentage of household members involved in water acquisition by season, gender and household size Number of household members who fetch water 0 1‐5 6‐10 11‐15 21‐25 36‐40 46‐50

Wet season Male Female

69.23 29.43 1.34 0 0 0 0

Dry season Male Female

Percent of respondents 0 45.64 0.67 83.11 50.17 82.83 15.54 4.18 15.15 0.68 0 0.34 0.34 0 0.34 0.34 0 0.34 0 0 0.34

Surprisingly, the number of times in a week that a household member involved in water acquisition undertakes a trip for water does not change significantly between the dry and the wet seasons. Members normally undertake a trip or two in the morning and again in the afternoon. Table 11 shows that respondents from East

50


Gonja and Bawku East Districts undertake the most number of trips for water, whilst those in Kassena ‐Nankana District undertake the least. Table. Number of times per week that household members fetch water for domestic use District Bawku East East Gonja Kassena ‐Nankana West Mamprusi Nanumba Yendi

Wet season (n=294) Mean Min Max 19.1 3 140 35.1 2 175 5.1 3 15 11.5 2 49 29.5 3 63 24.6 2 42

Dry season (n=293) Mean Min Max. 19.9 2 149 34.1 3 185 13.8 5 14 12.2 0 49 29.4 6 63 34.1 16 126

n refers to number of households surveyed

Rainwater harvesting from household roofs The data from the household survey revealed that a high percentage of inhabitants in Northern Ghana do not collect and store rainwater. On the average, only 37.7% (113) of the 300 households indicated they harvest rainwater for domestic use. Except in the Kassena ‐Nankana District that 74 % indicated that they harvest and use roof rainwater, the average number of households harvesting rainwater from five other Districts is 30.4 %. Among those households not harvesting rainwater, 66.8% have only thatch roofs. Thus 20.6 % of households surveyed who have aluminium roofed houses do not practice rainwater harvesting. We observed that for households that harvest rainwater, the water is channelled through gutters made of aluminium, and typically not exceeding 1 m in length, or the water is collected from the eaves of the roofs without special spouts constructed. Use of stored water for income generating activities A large proportion of households in Northern Ghana rely on stored water for income generating ventures. Of the households who responded to the survey, 88.4 % in five Districts rely on stored water for a significant proportion of the household’s income. The exception was encountered in the East Gonja District where only 30 % of households indicated that water is used in their income generation. Among the economic activities in which water was employed are crop processing (shea nut, rice, groundnuts, Parkia), food vending (preparing rice, maize porridge, kenkey, tubani for sale), watering of livestock, gardening, brewing, composting, charcoal production, and building of houses and kraals. The major uses recorded were crop

51


processing, watering of livestock gardening and food vending (Fig 5). A number of households were engaged in combinations of these activities, but we encountered one household engaged in all four major activities. Crop processing and preparation of food for sale is undertaken by women, whereas gardening and livestock watering is the preserve of men.

Gardening (men)

Food preparation for sale (women)

Crop processing (women)

Livestock watering (men)

Fig 5. Prop o rtion of ho useh old s in six distric ts of northern Ghana engaged in various income ge nerating ac tivities that e mp loy stored w ate r

Perceptions on soil fertility, and soil fertility management Approximately 98 % of the respondents indicated that fertility of their farmlands is in decline. Assigning a crop to a particular farmland depends on its importance to a household, with millet, sorghum and maize being placed on the best soils. Groundnut and cowpea were mentioned as secondary crops. Rice, soybeans, sweet potato and cotton are considered minor crops. Inorg anic fertiliser only

Animal manure only

Plant residue only

Inorg anic fertiliser + animal ma nure Inorg anic fertiliser + plant residues Animal manure + plant residues

Fig 6. Proportion of households indicating use o f various soil am end me nts

Inorg anic fertiliser + animal manure + plant residues

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To increase the yield of their crops, 96 % of the respondents indicated that they apply one form of fertiliser or another. Most households apply inorganic fertilizer, but only in combination with other organic materials (Fig 6). The least popular appear to be plant residue (plant parts in various stages of decomposition) or animal manure applied alone. These soil amendments are applied to millet, sorghum and maize, mainly. We realised from the survey that composting is popular among farmers. Up to 80.5 % of respondents indicated that they practice composting. For those not producing compost, the reasons provided include the scarcity of materials, lack of know‐how, scarcity of water, lack of transport to cart compost and busy schedule. The materials used in composting, as indicated by the respondents were mainly crop residues, animal manure and wood ash. There were others that received mention by very few farmers. These include neem leaves, grass and topsoil. The crop residues were mainly groundnut vines, and cereal stalks. The farmers mentioned that animal manure was the most limiting raw material. In general, of the households actively producing and using compost 45.2 % indicated that adequacy of raw materials was an important limitation to compost production. Availability of water for composting was the second most important constraint for those producing compost (Figure 7). Inadequate raw materials only Inadequate raw materials + water Adequate Water + materials Inadequate water only

Fig 7. Percent of households indicating constraints of availability of water and raw ma terials for com po sting in selec ted Districts in Northern Gha na

The respondents indicated various reasons for producing and using compost on their farmlands. These include doubling grain yield as compared with yield from the same area of unfertilised land, faster growth rate of crops, and drought tolerance.

53


Provision of domestic rainwater harvesting and storage systems Responses from the survey reinforced our belief that adequate water for domestic needs is a key determinant of the labour available for a household to engage in income generation. To proof this concept that harvesting and storing rainwater will free women and children from the drudgery of long daily trips for water, and offer opportunities for income generation, we have designed and introduced a ferro‐ cement reservoir in 44 households in 8 Districts across Northern Ghana. In each community each of three households were provided with 4 partially‐ buried ferro‐ cement reservoirs, each designed to hold 5,000 litres of water together with a collecting system. In the next post‐rainy season this is expected to make available to the household 20,000 litres of water. This is expected to provide an average household with fixed usage of 150 litres/day with more than 130 days supply of water.

Plate 7: An exa mp le of the wa ter harvesting reservoirs

The steps involved an initial removal of earth is removed from the demarcated area such that the excavate area has dimensions of 2 m diameter at the top (soil surface) and 0.8 m diameter at the bottom (Plate 8a). Mortar obtained from a blend of river sand and cement is then used to plaster the excavation, providing the base of the pot. Typically each 5,000 litre reservoir requires six 50 kg bags of cement and 2,000 cm3 of river sand. When the plastering is completed the paper bags from which the cement were poured are used to line the base of the pot, and then filled with earth, in the typical mould of a traditional clay pot, to a height of approximately 1.8 m from the base of the pot. The earth is then plastered with mortar and left for at least 12 hours. The earth is later removed together with the paper lining, and the inner surface of the pot is smoothened with mortar using a hand trowel.

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Reference Development Technology Unit (DTU)(2000). Technical Release series. TR‐RWH 01. Partially below ground (PBG) tank for rainwater storage. Instructions for manufacture. Warwick University. Technical release.16pp Development Technology Unit (DTU)(1999). Single –skin, externally reinforced brick. Instructions for manufacturers. Warwick University. Technical release. 9pp Development Technology Unit (DTU)(1999). Low‐cost, thin‐shell, 2m diameter ferrocement tank cover. Instructions for manufacturer’s. Warwick University. Technical release.12p Development Technology Unit (DTU)(2000). DTU Technical Release Series ‐ TR‐ RWH05. Warwick University. Technical release. Development Technology Unit (DTU)(2000). Ferro‐Cement Jar. Instructions for manufacturer. Warwick University. Technical release.14pp. Development Technology Unit (DTU)(2000). Brick jars. Instructions for manufacturers. Technical release.14pp Bishop‐Sambrook and Akther,S.(2001).Social and Gender Analysis. Findings from the inception stage. Presentation at the meeting of the inaugural programme. Hambatota, Sri‐ Lanka.18pp.

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Bamatraf, A. 1994, Water Harvesting and Conservation Systems in Yemen. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 169‐189, FAO, Rome. Ben‐Asher, J. 1988, A Review of Water Harvesting in Israel. World Bank Working Paper 2. World Bank Sub‐Saharan Water Harvesting Study, p. 47‐69. Boers, T. M. and Ben‐Asher, J. 1982, A review of rainwater harvesting. Agric. Water Management 5: 145‐158 Bruins, H. J.; Evenari M. and Nessler. U. 1986, Rainwater ‐harvesting for Food Production in Arid Zones. Applied Geography 6, 13‐32, Catch Water, 2003, Global Water Partnership News, Vol. 5, No. 2, April – May 2003. Critchley, W R S and Reij, C. 1989. Water harvesting for plant production: Part 2. Case studies and conclusions from sub0Sahara Critchley, W. and Siegert, K. 1991, A manual for the design and construction of water harvesting schemes for plant production, with contributions from: Chapman, C. and Finkel, M., FAO, Rome. Critchley, W.; Reij, C. and Seznec, A. 1992a, Water Harvesting for Plant Production. Vol 2. Case Studies and Conclusions from Sub‐Saharan Africa. World Bank Techn. Paper 157. Critchley, W.; Reij, C. and Turner, S. D. 1992b, Soil and Water Conservation in Sub‐Saharan Africa: towards sustainable production by the rural poor. IFAD, Rome and CDCS, Amsterdam. Critchley, Will and Klaus Siegert. A Manual for the Design and Construction of Water Harvesting Schemes for Plant Production. Rome: Food and Agriculture Organization of the United Nations, 1991 Development Technology Unit (DTU)(1999). Single –skin, externally reinforced brick. Instructions for manufacturers. Warwick University. Technical release. 9pp

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Development Technology Unit (DTU)(1999). Low‐cost, thin‐shell, 2m diameter ferrocement tank cover. Instructions for manufacturer’s. Warwick University. Technical release.12p Development Technology Unit (DTU)(2000). DTU Technical Release Series ‐ TR‐ RWH05. Warwick University. Technical release. Development Technology Unit (DTU)(2000). Ferro‐Cement Jar. Instructions for manufacturer. Warwick University. Technical release.14pp. Development Technology Unit (DTU)(2000). Brick jars. Instructions for manufacturers. Technical release.14pp Esser, K. 1999, Water Harvesting in Dryland Farming, Agricultural Univ., of Norway, Noragric, Centre for Environment and Development Sudies, Noragric Brief, No.:99/7. Evenari, M.; Shanan, L. and Tadmor, N. 1971, The Negev: The Challenge of a Desert. Harvard Univ., Press Cambridge, MA., U.S.A. Finkel and Z. Naveh, Semi‐arid Soil and Water Conservation. CRC Press, Inc., Boca Raton, Florida: USA, p.93‐101. Finkel, H. J. and Finkel, M. 1986, Engineering Measures: Water Harvesting. In: Finkel H.J, M. Frasier, G. W. 1994, Water Harvesting/Runoff Farming Systems for Agricultural Production. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 57‐73, FAO, Rome. French, N. and Hussain, J. 1964, Water Spreading Manual. Range Management Re. 1, Pakistan Range Impr. Scheme. Lahore, Pakistan. Gibberd, V. (1993). Final report EMI dryland farming and dryland applied Gilbertson, D. D. 1986, Runoff (floodwater) farming and rural water supply in arid lands. In: Appl. Geogr. 6:5‐11. Gould, J.; Gould, J.; Lane, J.; Lambert, A.O.; Turton, P.; Dickinson, M.A. and G. Preston, G. 2000, Assessment of Water Supply Options, Final Draft: May 2000, Options Assessment IV.3, Prepared for the WCD by:D.C. Sutherland and C.R. Fenn (WS 58

Atkins Consultants Ltd), With contributions from:World Commission on Dams Secretariat, Harvesting. The World Commission on Dams, Cape Town, South Africa, Report: Dams and Development. (http://www.damsreport http://www.damsreport.org/docs/kba .org/docs/kbase/thematic se/thematic/drafts/tr43_ /drafts/tr43_finaldraft.pdf finaldraft.pdf)) Ibrahim, H. 1994, Rainwater Harvesting in Dier‐Atye (Syria). In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 73‐ 86, FAO, Rome. Kolarkar, A. S.; Murthy, K. N. K. and Singh, N. 1980, Water Harvesting and Runoff Farming in Arid Rajasthan, Indian Journal Indian Journal of Soil Conservation. 8 (2), (http://www.unccd.int/cop/rep http://www.unccd.int/cop/reports/asia/ orts/asia/national/20 national/2000/india 00/india ‐eng.pdf). eng.pdf). Kutsch, H. 1982, Principle Features of a Form of Water‐concentrating Culture on Small‐Holdings With Special Reference to the Anti‐Atlas. Trierer Geogr. Studien 5. Trier. Laing, I. A. F. 1981, Rainfall Collection in Australia. In: Dutt, G.R. et al. (eds.), Rainfall Collection for Agriculture in Arid and Semiarid Regions, p. 61‐66. Commonwealth Agric. Bureaux, Slough, UK. Lalljee, B. and Facknath, S. 1999, Water Harvesting and Alternate Sources of Water forAgriculture, PROSI Magazine – September 1999 – N 368 – Agriculture. Lee, M.D. and J.T. Visscher 1990. Water harvesting in Five African Countries. IRC Occasional Paper No. 14, 108 p. Lövenstein, H. 1994, From Water Harvesting to Crop Harvesting‐Opportunities for the Efficient Use of Runoff Water by Crops. In: FAO, Water Harvesting For Improved AgriculturalProduction. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 301‐315, FAO, Rome. Mittal S.P. and Aggarwal R. K. 2001, Rainwater Harvesting Need of the Hour, The Tribune, Agriculture Tribune, Monday, April 16, 2001, Chandigarh, India, Managem. 5:145‐158. (http://www.tribuneindia.com/20 http://www.tribuneindia.com/2001/2001 01/20010416/agro 0416/agro.htm .htm). ). Nasr, M. 1999, Assessing Desertification and Water Harvesting in the Middle East and NorthAfrica:Number 10, Policy Implications ZEF – Discussion Papers

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on Development Policy,Bonn, ZEF Bonn, Zentrum für Entwicklungsforschung, Center for Development Research,Universität Bonn. Oweis, T. and Prinz, D. 1994, Identification of Potential Water Harvesting Areas and Methods for the Arid Regions of West Asia and North Africa: Proposal for a Regional Research Project. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 401‐412, FAO, Rome. Oweis, T. and Taimeh, A. 1994, Overall Evaluation of On‐Farm Water Harvesting Systems in the Arid Regions, In: Lacirignola, C. and A. Hamdy (eds). Proceedings, CIHEAM Conference “Land and Water Resources Management in the Mediterranean Region” 04. – 08. September, 1994, Valencano (Bari), Vol. III, p. 763‐781. Oweis, T.; Hachum, A. and Kijne, J. 1999, Water harvesting and supplementary irrigation, for improved water use efficiency in dry areas. SWIM Paper 7, Colombo, Sri Lanka, International Water Management Institute. Oweis, T.; Prinz, D. and Hachum, A. 2001, Water Harvesting, Indigenous Knowledge for the Future of the Drier Environments, ICARDA, Aleppo, Syria. Pacey A. and Cullis A. 1986, Rainwater Harvesting. The collection of rainfall and runoff in rural areas. Intermediate Technology Publ., London. Pacey, A and Cullis, A. 1986. Rainwater harvesting; The Collection of rainfall and runoff in rural areas. IT Publication, London. Pacey, A. and Cullis, A. 1991, Rainwater Harvesting. The collection of rainfall and runoff in rural areas. Intermediate Technology Publ., London. Patencheru, India. Prinz, D. 1994, Water Harvesting and Sustainable Agriculture in Arid and Semi‐ arid Regions. In: Lacirignola, C. and A. Hamdy (eds). Proceedings, CIHEAM Conference “Land and Water Resources Management in the Mediterranean Region” 04. – 08. September, 1994, Valencano (Bari), Vol. III, p. 745‐762. Prinz, D. 1996, Water Harvesting: Past and Future. In: Pereira, L. S. (ed.), Sustainability of Irrigated Agriculture. Proceedings, NATO Advanced Research Workshop, Vimeiro, 21‐ 26.03.1994, Balkema, Rotterdam, 135‐144 60

Prinz, D. 2002, The Role of Water Harvesting in Alleviating Water Scarcity in Arid Areas. Keynote Lecture, Proceedings, International Conference on Water Resources Management in Arid Regions. 23‐27 March, 2002, Kuwait Institute for Scientific Research, Kuwait, (Vol. III, 107‐122). Prinz, D. and Singh A. K. 2000, Technological Potential for Improvements of Water Prinz, D.; Tauer, W. and Vögtle, Th. 1994, Application of Remote Sensing and Geographic Information Systems for Determining Potential Sites for Water Harvesting. Proceedings, Expert Consultation on Water Harvesting for Improved Agricultural Production. Cairo, 21 – 25 Nov. 1993. FAO, Rome, 135‐144. Prinz, D.; Tauer, W. and Vögtle, Th. 1994, The Application of Geographic Information Systems to Identify Areas Suitable for Water Harvesting/Runoff Irrigation. Proceedings, XII CIGR World Congress, Milano 29.08 – 01.09.1994, Vol. I, p. 79 – 87.Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 113‐132, FAO, Rome. Reij, C.; Mulder, P. and L. Begemann 1988, Water Harvesting for Plant Production. World Bank Techn. Paper. Washington DC. Research project, 1998‐1993. Rosegrant, M.W.; Cai, X.; Cline, S. and Nakagawa, N. 2002, The Role of Rainfed Agriculture in the Future of Global Food Production, EPTD DISCUSSION PAPER NO. 90, Environment and Production Technology Division, International Food Policy Research Institute, 2033 K Street, N.W., Washington, D.C. 20006 U.S.A. runoff harvesting on maize yield in semi‐arid Eastern Kenya. KARI‐ Katumani Ryan, J. G.; Sarin, R and Pereia, M. 1980, Assessment of Prospective Soil‐Water‐ and Crop Management Technologies for the Semi‐arid Tropics of Peninsular India. ICRISAT, Siegert, K. 1994, Introduction to Water Harvesting. Some Basic Principles for Planning, Design and Monitoring. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 9‐ 23, FAO, Rome. Sustainable Agriculture 3: 305‐315. 61

Tauer, W. and Humborg, G. 1992, Runoff Irrigation in the Sahel Zone: Remote Sensing and Geographic Information Systems for Determining Potential Sites. Markgraf, Weikersheim. Thompson, D.; Quashie‐Sam, J. and McGregor, D. 2001, Testing the Feasibility of Water Harvesting as a Supplement to Clean Water Supply in Peri‐Urban Kumasi, Series Editors: Duncan McGregor and James Quashie ‐Sam, CEDAR/IRNR Kumasi Paper 8, (http://glacier.gg.rhbnc.ac.uk/kumasi/Project_Related_Papers/Cedar_IRNR/Paper _8/paper_8.html). Tobbi, B. 1994, Water Harvesting: Historic, Existing and Potentials in Tunisia. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 189‐201, FAO, Rome. UNEP 1983, Rain and Stormwater Harvesting in Rural Areas. Tycooly, Dublin. Van Dijk, J. and Reij C. 1994, Indigenous Water Harvesting Techniques in Sub‐ Saharan Africa: Examples from Sudan and the West African Sahel. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 101‐112, FAO, Rome. Vijayalakshmi, K.; Vittal, K. P. R. and Singh, L. R. P. 1982, Water Harvesting and Re‐use. In: ICAR. A Decade of Dryland Agricultural Research in India 1971‐1980, p. 103‐119. New Delhi, India.

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Abdi, A. M. 1986, Water harvesting systems in the Northwestern region of Somalia. Paper presented to the World Bank Workshop on Water Harvesting in Sub‐Saharan Africa, Baringo, Kenya, 13‐17. Oct 1986. Baringo, Kenya. A Sourcebook for Green and Sustainable Building, Harvested Rainwater, 1994, www.greenbuilder.com Achouri, M. 1994, Small Scale Water Harvesting in Tunisia. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 87‐ 97, FAO, Rome. Al‐Labadi, M. 1994, Water Harvesting in Jordan‐Existing and Potential Systems. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 221‐231, FAO, Rome. Alternative Treatments of Water Harvesting in Highland Balochistan, Pakistan. J. of Annual report 2000. Antinori, P. and Vallerani, V. 1994, Experiments in Water Harvesting Technology with the Dolphin and Train Ploughs. In: FAO, Water Harvesting For Improved Agricultural Bamatraf, A. 1994, Water Harvesting and Conservation Systems in Yemen. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 169‐189, FAO, Rome. Ben‐Asher, J. 1988, A Review of Water Harvesting in Israel. World Bank Working Paper 2. World Bank Sub‐Saharan Water Harvesting Study, p. 47‐69. Boers, T. M. and Ben‐Asher, J. 1982, A review of rainwater harvesting. Agric. Water Management 5: 145‐158 Bruins, H. J.; Evenari M. and Nessler. U. 1986, Rainwater ‐harvesting for Food Production in Arid Zones. Applied Geography 6, 13‐32, Catch Water, 2003, Global Water Partnership News, Vol. 5, No. 2, April – May 2003. Critchley, W R S and Reij, C. 1989. Water harvesting for plant production: Part 2. Case studies and conclusions from sub0Sahara

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Critchley, W. and Siegert, K. 1991, A manual for the design and construction of water harvesting schemes for plant production, with contributions from: Chapman, C. and Finkel, M., FAO, Rome. Critchley, W.; Reij, C. and Seznec, A. 1992a, Water Harvesting for Plant Production. Vol 2. Case Studies and Conclusions from Sub‐Saharan Africa. World Bank Techn. Paper 157. Critchley, W.; Reij, C. and Turner, S. D. 1992b, Soil and Water Conservation in Sub‐Saharan Africa: towards sustainable production by the rural poor. IFAD, Rome and CDCS, Amsterdam. Critchley, Will and Klaus Siegert. A Manual for the Design and Construction of Water Harvesting Schemes for Plant Production. Rome: Food and Agriculture Organization of the United Nations, 1991 Development Technology Unit (DTU)(1999). Single –skin, externally reinforced brick. Instructions for manufacturers. Warwick University. Technical release. 9pp

Development Technology Unit (DTU)(1999). Low‐cost, thin‐shell, 2m diameter ferrocement tank cover. Instructions for manufacturer’s. Warwick University. Technical release.12p Development Technology Unit (DTU)(2000). DTU Technical Release Series ‐ TR‐ RWH05. Warwick University. Technical release. Development Technology Unit (DTU)(2000). Ferro‐Cement Jar. Instructions for manufacturer. Warwick University. Technical release.14pp. Development Technology Unit (DTU)(2000). Brick jars. Instructions for manufacturers. Technical release.14pp

Evenari, M.; Shanan, L. and Tadmor, N. 1971, The Negev: The Challenge of a Desert. Harvard Univ., Press Cambridge, MA., U.S.A. Finkel and Z. Naveh, Semi‐arid Soil and Water Conservation. CRC Press, Inc., Boca Raton, Florida: USA, p.93‐101.

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Finkel, H. J. and Finkel, M. 1986, Engineering Measures: Water Harvesting. In: Finkel H.J, M. Frasier, G. W. 1994, Water Harvesting/Runoff Farming Systems for Agricultural Production. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 57‐73, FAO, Rome. French, N. and Hussain, J. 1964, Water Spreading Manual. Range Management Re. 1, Pakistan Range Impr. Scheme. Lahore, Pakistan. Gibberd, V. (1993). Final report EMI dryland farming and dryland applied Gilbertson, D. D. 1986, Runoff (floodwater) farming and rural water supply in arid lands. In: Appl. Geogr. 6:5‐11. Gould, J.; Lane, J.; Lambert, A.O.; Turton, P.; Dickinson, M.A. and G. Preston, G. 2000, Assessment of Water Supply Options, Final Draft: May 2000, Options Assessment IV.3, Prepared for the WCD by:D.C. Sutherland and C.R. Fenn (WS Atkins Consultants Ltd), With contributions from:World Commission on Dams Secretariat, Harvesting. The World Commission on Dams, Cape Town, South Africa, Report: Dams and Development. (http://www.damsreport.org/docs/kbase/thematic/drafts/tr43_finaldraft.pdf) Ibrahim, H. 1994, Rainwater Harvesting in Dier‐Atye (Syria). In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 73‐ 86, FAO, Rome. Smet Jo and Moriarty, P., 2001, Rooftop Rainwater Harvesting, DGIS Policy Supporting Paper Kolarkar, A. S.; Murthy, K. N. K. and Singh, N. 1980, Water Harvesting and Runoff Farming in Arid Rajasthan, Indian Journal of Soil Conservation. 8 (2), (http://www.unccd.int/cop/reports/asia/national/2000/india ‐eng.pdf). Kutsch, H. 1982, Principle Features of a Form of Water‐concentrating Culture on Small‐Holdings With Special Reference to the Anti‐Atlas. Trierer Geogr. Studien 5. Trier.

65

Lee, M.D. and J.T. Visscher 1990. Water harvesting in Five African Countries. IRC Occasional Paper No. 14, 108 p. Lövenstein, H. 1994, From Water Harvesting to Crop Harvesting‐Opportunities for the Efficient Use of Runoff Water by Crops. In: FAO, Water Harvesting For Improved AgriculturalProduction. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 301‐315, FAO, Rome. Mittal S.P. and Aggarwal R. K. 2001, Rainwater Harvesting Need of the Hour, The Tribune, Agriculture Tribune, Monday, April 16, 2001, Chandigarh, India, Managem. 5:145‐158. (http://www.tribuneindia.com/2001/20010416/agro.htm). Nasr, M. 1999, Assessing Desertification and Water Harvesting in the Middle East and NorthAfrica:Number 10, Policy Implications ZEF – Discussion Papers on Development Policy,Bonn, ZEF Bonn, Zentrum für Entwicklungsforschung, Center for Development Research,Universität Bonn. Oweis, T. and Prinz, D. 1994, Identification of Potential Water Harvesting Areas and Methods for the Arid Regions of West Asia and North Africa: Proposal for a Regional Research Project. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 401‐412, FAO, Rome. Oweis, T. and Taimeh, A. 1994, Overall Evaluation of On‐Farm Water Harvesting Systems in the Arid Regions, In: Lacirignola, C. and A. Hamdy (eds). Proceedings, CIHEAM Conference “Land and Water Resources Management in the Mediterranean Region” 04. – 08. September, 1994, Valencano (Bari), Vol. III, p. 763‐781. Oweis, T.; Hachum, A. and Kijne, J. 1999, Water harvesting and supplementary irrigation, for improved water use efficiency in dry areas. SWIM Paper 7, Colombo, Sri Lanka, International Water Management Institute. Oweis, T.; Prinz, D. and Hachum, A. 2001, Water Harvesting, Indigenous Knowledge for the Future of the Drier Environments, ICARDA, Aleppo, Syria. Pacey A. and Cullis A. 1986, Rainwater Harvesting. The collection of rainfall and runoff in rural areas. Intermediate Technology Publ., London.

66

Pacey, A and Cullis, A. 1986. Rainwater harvesting; The Collection of rainfall and runoff in rural areas. IT Publication, London. Pacey, A. and Cullis, A. 1991, Rainwater Harvesting. The collection of rainfall and runoff in rural areas. Intermediate Technology Publ., London. Patencheru, India. Prinz, D. 1994, Water Harvesting and Sustainable Agriculture in Arid and Semi‐ arid Regions. In: Lacirignola, C. and A. Hamdy (eds). Proceedings, CIHEAM Conference “Land and Water Resources Management in the Mediterranean Region” 04. – 08. September, 1994, Valencano (Bari), Vol. III, p. 745‐762. Prinz, D. 1996, Water Harvesting: Past and Future. In: Pereira, L. S. (ed.), Sustainability of Irrigated Agriculture. Proceedings, NATO Advanced Research Workshop, Vimeiro, 21‐ 26.03.1994, Balkema, Rotterdam, 135‐144 Prinz, D. 2002, The Role of Water Harvesting in Alleviating Water Scarcity in Arid Areas. Keynote Lecture, Proceedings, International Conference on Water Resources Management in Arid Regions. 23‐27 March, 2002, Kuwait Institute for Scientific Research, Kuwait, (Vol. III, 107‐122). Prinz, D. and Singh A. K. 2000, Technological Potential for Improvements of Water Prinz, D.; Tauer, W. and Vögtle, Th. 1994, Application of Remote Sensing and Geographic Information Systems for Determining Potential Sites for Water Harvesting. Proceedings, Expert Consultation on Water Harvesting for Improved Agricultural Production. Cairo, 21 – 25 Nov. 1993. FAO, Rome, 135‐144. Prinz, D.; Tauer, W. and Vögtle, Th. 1994, The Application of Geographic Information Systems to Identify Areas Suitable for Water Harvesting/Runoff Irrigation. Proceedings, XII CIGR World Congress, Milano 29.08 – 01.09.1994, Vol. I, p. 79 – 87.Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 113‐132, FAO, Rome. Reij, C.; Mulder, P. and L. Begemann 1988, Water Harvesting for Plant Production. World Bank Techn. Paper. Washington DC. Research project, 1998‐1993.

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Rosegrant, M.W.; Cai, X.; Cline, S. and Nakagawa, N. 2002, The Role of Rainfed Agriculture in the Future of Global Food Production, EPTD DISCUSSION PAPER NO. 90, Environment and Production Technology Division, International Food Policy Research Institute, 2033 K Street, N.W., Washington, D.C. 20006 U.S.A. runoff harvesting on maize yield in semi‐arid Eastern Kenya. KARI‐ Katumani Ryan, J. G.; Sarin, R and Pereia, M. 1980, Assessment of Prospective Soil‐Water‐ and Crop Management Technologies for the Semi‐arid Tropics of Peninsular India. ICRISAT, Siegert, K. 1994, Introduction to Water Harvesting. Some Basic Principles for Planning, Design and Monitoring. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 9‐ 23, FAO, Rome. Sustainable Agriculture 3: 305‐315. Tauer, W. and Humborg, G. 1992, Runoff Irrigation in the Sahel Zone: Remote Sensing and Geographic Information Systems for Determining Potential Sites. Markgraf, Weikersheim. Thompson, D.; Quashie‐Sam, J. and McGregor, D. 2001, Testing the Feasibility of Water Harvesting as a Supplement to Clean Water Supply in Peri‐Urban Kumasi, Series Editors: Duncan McGregor and James Quashie ‐Sam, CEDAR/IRNR Kumasi Paper 8, (http://glacier.gg.rhbnc.ac.uk/kumasi/Project_Related_Papers/Cedar_IRNR/Paper _8/paper_8.html). Tobbi, B. 1994, Water Harvesting: Historic, Existing and Potentials in Tunisia. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 189‐201, FAO, Rome. UNEP 1983, Rain and Stormwater Harvesting in Rural Areas. Tycooly, Dublin. Van Dijk, J. and Reij C. 1994, Indigenous Water Harvesting Techniques in Sub‐ Saharan Africa: Examples from Sudan and the West African Sahel. In: FAO, Water Harvesting For Improved Agricultural Production. Expert Consultation, Cairo, Egypt 21‐25 Nov. 1993, p. 101‐112, FAO, Rome.

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