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Harvesting Rainfall a Key Climate Adaptation Opportunity for Africa

UNEP and World Agroforestry Centre Underscore the Continent's Untapped Potential to Boost Agriculture and Drinking Water Supplies

Nairobi, 13 November 2006 - The massive potential of rainwater harvesting in Africa is underlined in a new report released today at the climate convention talks in Nairobi.

The report, compiled by the United Nations Environment Programme (UNEP) and the World Agroforestry Center, concludes that many communities and countries suffering or facing water shortages as a result of climate change could dramatically boost supplies by collecting and storing rain falling freely from the clouds.

Kenya, for example, with a population of somewhere under 40 million people, actually has enough rainfall to supply the needs of six to seven times its current population.

Ethiopia, where just over a fifth of the population are covered by domestic water supply and an estimated 46 per cent of the population suffer hunger, has a potential rainwater harvest equivalent to the population needs of over 520 million people.

Not all can or should be harvested for drinking water and agricultural uses. Indeed over a third of rainfall is needed to sustain the wider environment including forests, grasslands and healthy river flows.

It makes the actual rainwater harvesting potential somewhat less but still much more than adequate to meet a significant slice of population needs.

Until recently the importance of rainwater harvesting as a buffer against climate-linked extreme weather events has been almost invisible in water planning with countries relying almost exclusively on rivers and underground supplies, says the report.

UNEP and the World Agroforestry Centre are urging governments and donors to invest more widely in a technology that is low cost, simple to deploy and maintain, and able to transform the lives of households, communities and countries Africa-wide.

Unlike big dams, which collect and store water over large areas, small-scale rainwater harvesting projects lose less water to evaporation because the rain or run-off is collected locally and can be stored in a variety of ways.

The report says rainwater harvesting also holds important potential for assisting managers of protected areas with the technology already having been tested to help wild animals in places like Nairobi and Tsavo national parks during drought.

Achim Steiner, UN Under-Secretary-General and UNEP Executive Director, said: "The figures are astonishing and will surprise many. It is important to emphasize however that it is not desirable, realistic or environmentally sensible to harvest every last drop for human needs.

Nevertheless, the numbers do underline the huge untapped potential for rainwater harvesting as a promising adaptation measure for coping with climate change that has largely gone unnoticed".

"Over the coming years we are going to need a range of measures and technologies to capture water and bolster supplies. Conserving and rehabilitating lakes, wetlands and other freshwater ecosystems will be vital and big dams, if sensibly and sustainably designed and constructed, may be part of the equation too. However, large-scale infrastructure can often by-pass the needs of poor and dispersed populations. Widely deployed, rainwater harvesting can act as a buffer against drought events for these people while also significantly supplementing supplies in cities and areas connected to the water grid," he added.

"Rainwater harvesting can also assist in meeting wider aspirations, including the Millennium Development Goals as they relate to fighting poverty and hunger, delivering environmental sustainability and gender equality. Maasai women, taking part in a pilot in Kisamese, Kenya, are gaining four hours in a day because of the reduced demands on their time to find and fetch water. Having water supplies on their doorstep has thus liberated them from a daily chore, giving them more time to spend on education, child-care, cultivation and alternative livelihoods," said Mr Steiner.

Dennis Garrity, Director General of the World Agroforestry Centre, said: 'In the popular mind. Africa is seen as a dry continent. But overall, it actually has more water resources per capita than Europe. However, much of Africa's rain comes in bursts and is rapidly swept away or is never collected. The time has come to realize the great potential for greatly enhancing drinking water supplies and smallholder agricultural production by harvesting more of the rain when and where it falls".

"Some countries are already successfully exploiting their rainwater. In South Australia, over 40 per cent of households use rainwater stored in tanks as their main source of drinking water. Germany has over half a million rainwater harvesting schemes. So this is not a second rate technology but a first rate, low cost one. It is a technology that needn't await further research and development. With little adaptation it is available now".

Last week Kenya's water minister announced plans to require all new buildings to include rainwater harvesting measures and similar plans have been drawn up in India where, via work coordinated by the Barefoot College, some 470 schools and community centres now collect 29 million litres of rainwater in regions where conventional supplies are unsafe as a result of salt contamination and metals.

The impact on lives and livelihoods of rainwater harvesting is underscored by a five-year-old project established by UNEP and the non-governmental organization EarthCare Africa with funding from the Government of Sweden. It is also now backed by the Regional Land Management Unit (RELMA) in the World Agroforestry Centre and the Rotary Society's Water & Sanitation Action Group (RWASP).

Rainwater harvesting equipment including containers and mini-reservoirs or "earth pans" have been installed in a Maasai community in Kisamese, Kajiado, some 30 minutes drive from Nairobi in the Ngong Hills.

The project has the capacity to store over half a million litres of water and has led to the development of small kitchen gardens and improved agricultural plots that are contributing to food security. Wood lots, which can be harvested for fuel for cooking, have also been established.

Agnes Mosoni Loirket, a Maasai community leader in Kisamese, said: "Accessibility of water has lessened the work load and time spent to fetch water. Before the project, some women used to leave early and sleep close to the river, leaving school children going to school unattended"..

RWASP, in alliance with UNEP and the World Agroforestry Centre, are planning to extend the Maasai pilot into other parts of Kenya and Africa.

Key Points from the Study

The report, compiled by UNEP and the Regional Land Management Unit of the World Agroforestry Centre, has mapped the rainwater harvesting potential of nine countries in Africa. These are Botswana, Ethiopia, Kenya, Malawi, Mozambique, Uganda, Tanzania, Zambia, and Zimbabwe.

Maps estimating the rainwater harvesting potential of Nairobi and Kampala have been completed and similar assessments are underway for Addis Ababa, Dar es Salaam, Kigali, Maputo, Lusaka, Lilongwe, and Harare.

The work is assessing the potential from various angles including the levels of rainwater that could be directly harvested from roofs, run-off on agricultural land, and from flood overflows.

Currently, 14 out of Africa's 53 countries are classed as water stressed or water scarce. A water stressed country has water availability of less than 1,700 cubic metres per person per year and a water scarce one less than 1,000 cubic metres per person per year.

It is estimated that the number of countries in Africa in this situation could double by 2025 to around half of all countries.

The report's overall conclusion is that "Africa is not water scarce. The rainfall contribution is more than adequate to meet the needs of the current population several times over. For example Kenya would not be categorized as a "water stressed country" if rainwater harvesting is considered. The water crisis in Africa is more of an economic problem from lack of investment, and not a matter of physical scarcity".

Overall the quantity of rain falling across the Continent is equivalent to the needs of nine billion people or one and half times the current global population.

Country Studies

Around a third of Africa is deemed suitable for rainwater harvesting if a threshold of 200 mm of rainfall a year is used. 200mm is considered to be at the lower end of the scale.

Ethiopia-the rainwater harvesting potential is estimated at over 11,800 cubic metres per person compared with annual renewable--river and ground water-- supplies of only around 1,600 cubic metres.

Kenya- the rainwater harvesting potential is estimated at over 12,300 cubic metres per person compared with the current annual renewable water availability of just over 600 cubic metres.

Uganda-the rainwater harvesting potential is estimated at over 9,900 cubic metres per person compared with the annual renewable water availability of 1,500 cubic metres.

Tanzania�the rainwater harvesting potential is estimated at over 24,700 cubic metres per person when compared with the annual renewable availability of around 2,200 cubic metres.

City Studies

Nairobi-Nairobi-The city could support the water needs of a population of between six and 10 million with 60 litres a day if rainwater were efficiently and effectively harvested. At present the city�s water supply potential is 460,000 cubic meters, but only 50% reach consumers due to leakages and illegal connections.

Kampala-The city could support the water needs of a population of between 3.5 million and 5.5 million with 60 litres a day if rainwater were efficiently and effectively harvested.

Notes to Editors

A more detailed evaluation of the rainwater harvesting potential, based on the new mapping study, can be found at www.unep.org and the World Agroforestry Centre www.worldagroforestry.org

Barefoot College is at www.barefootcollege.org

For More Information Please Contact Nick Nuttall, UNEP Spokesperson, on Tel: +254 20 7623084; Mobile: 0733-632 755; E-mail: nick.nuttall@unep.org

Or Elisabeth Waechter, Associate Information Officer, on Tel: +254 20 7623088, Mobile: 0720-173 968; E-mail: Elisabeth.waechter@unep.org


Further Resources

UNEP Resources on UNFCCC Climate Conference

Rain Water Harvesting
- Potential for Rainwater Harvesting in Africa
- Potential for Rain Water Harvesting in ten African Cities:

Rainwater & the MDGs Booklet (PDF):
- Introduction
- Case Studies
- Rainwater Harvesting & Disaster Management

Maps of Rainwater Harvesting in Africa

Global Rainwater Partnership

World Agroforestry Centre (ICRAF)

UNEP Resources on Freshwater

Vital Water Graphics

Dams and Development Project

UNEP Resources on Climate Change

Regional Office for Africa

African Cities Symposium on Climate Change