Rainwater Harvesting

By Dan Kane

In sub-Saharan Africa, many farmers are already watching their crop yields dwindle as water becomes more scarce and difficult to access. Even in areas where freshwater is still available, technologies such as pumps and filtration facilities can be prohibitively expensive.

Innovations in irrigation, such as this home-made water pump, are helping many small-scale farmers in sub-Saharan Africa. (Photo credit: Bernard Pollack)

Maintaining food security in Africa, especially as climate change takes a bigger hold on the continent, will require finding inexpensive, sustainable ways of obtaining freshwater. Fortunately, some farmers have already found their solution by returning to an age-old practice of rainwater harvesting.

Rainwater usually infiltrates the soil and is retained within the first foot or so, but a significant portion is also lost to evaporation and runoff. Most sub-Saharan African nations are using less than 5 percent of their rainwater potential. Capturing even a fraction of rainwater can provide several gallons for consumption and irrigation at minimal cost.

While researching for the recently released State of the World 2011: Innovations that Nourish the Planet report, Nourishing the Planet found that with the help of international NGOs, many communities across Africa have installed successful rainwater harvesting techniques that are cheap and useful.

In Rwanda, the World Agroforestry Centre of Nairobi, Kenya has collaborated with the country’s Ministry of Agriculture and Animal Resources to help farmers construct systems to funnel rainwater runoff into ponds lined with plastic sheets that can hold more than 30,000 gallons (113,562 liters). Farmers can then use simple, inexpensive siphons and foot pumps to collect this water for irrigation. Over 400 such ponds have already been built across ten districts and another 800 are slated for construction in the near future.

And in Kenya, the World Agroforestry Centre has been working with the United Nations Environment Programme (UNEP) to build cement tanks for Maasai women that collect water off of rooftops. These tanks provide a domestic supply of water that eliminates the burden of having to travel long distances to collect water every day—a burden often borne by young girls.

These water-saving initiatives are helping to improve food security and livelihoods in many parts of sub-Saharan Africa.

Dan Kane is a research intern with Nourishing the Planet.

To purchase your own copy of State of the World 2011: Innovations that Nourish the Planet, please click HERE. And to watch the one minute book trailer, click HERE.

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