Unlocking the potential of sand rivers

Our vision

The vision of the sand river alliance is that farming families in the drylands of Sub-Saharan Africa can become prosperous through turning locally available resources into secure diversified diets and higher incomes. These available resources include water from sand river aquifers, soils, energy, and agricultural and entrepreneurial skills.

Climate-smart agriculture in African drylands is possible through unlocking the potential of nature-based water storage in sand rivers. Sand rivers can be lifelines for resilient livelihoods.

The concept

Most people living in the drylands of Sub-Saharan Africa, comprising zones between semi-arid and arid lands, have insecure livelihoods and many belong to the poor. Here rainfed crop cultivation is risky due to frequently occurring long dry spells during the rainy season. In many of these drylands, harvests fail every other year. As a result farmers are reluctant to invest in their cultivation, e.g. fertilizers, because if the crop fails, also the money invested is lost. They rather invest in small ruminants and livestock that can graze on the rangelands. But most nevertheless remain poor.

There is however a way to make farming climate smart, namely through irrigation. But where to find water in these drylands? The answer may be surprising: in the seemingly dry sand rivers that crisscross these drylands. These are seasonal (also known as ephemeral) rivers that experience only a few flow events per year, and fall dry most of the time. Many of these sand rivers have a river bed that consists of a thick layer of coarse sand that lies on impervious or less pervious soil layers. This sand layer can store a lot of water, and, importantly, that water does not evaporate (which would occur if a large dam would collect the water during flow events). So most dry rivers are not dry at all, but rather form a nature-based “cradle” for the scarce water. Another important feature of this water is that it occurs at shallow depths, which thus requires relatively little energy to access and use it to irrigate crops.

Once a farming household has access to this sand river water, it can “drought-proof” the crops it grows, and thus may be in a position to invest in fertilizer and other inputs to increase yields.

Creating climate-smart livelihoods in the harsh drylands of Sub-Saharan Africa is therefore a real possibility!

One of the innovations our alliance has developed is a method to construct a well-point that can be hand-drilled, that has a water yield that is sufficient for irrigating at least 1 ha, and that costs less than $100 and can be constructed within a day. Smallholder farmers in Zimbabwe and Mozambique have connected small solar-powered pumps to these well-points, and irrigate vegetables and staple crops initially at 2,000 m² per well-point. Part of the produce they sell for cash, typically at a value of between $100 and $500 per season.