Africa: New Study Calls for More Water Storage Options for Farmers
By Henry Neondo
Increasingly erratic rainfall related to climate change will pose a major threat to food security and economic growth, especially in Africa and Asia, a new report now warns that there is need to boost investment in diverse forms of water storage as an effective remedy.
“Millions of farmers in communities dependent on rainfed agriculture are at risk from decreasing and erratic availability of water,” said Colin Chartres, director general of the Sri Lanka-based International Water Management Institute, IWMI.
The report argues against overreliance on single solutions like big dams, proposing instead an integrated approach that combines large- and small-scale storage options, including the use of water from natural wetlands, water stored in the soil, groundwater beneath the earth’s surface and water collected in ponds, tanks and reservoirs.
“Just as modern consumers diversify their financial holdings to reduce risk, smallholder farmers need a wide array of ‘water accounts’ to provide a buffer against climate change impacts,” said Matthew McCartney, the report’s lead author and a hydrologist at IWMI, which is supported by the Consultative Group on International Agricultural Research (CGIAR). “That way, if one water source goes dry, they’ll have others to fall back on.”
IWMI and its research partners estimate that up to 499 million people in Africa and India can benefit from improved agricultural water management.
In Asia, where irrigation was greatly expanded in recent decades, rainfed agriculture is still extensive, accounting for 66 percent of the total cropped area, the IWMI study notes.
In sub-Saharan Africa, the proportion is far greater at 94 percent. Yet, these are precisely the regions where water storage infrastructure is least developed.
“Unless we can reduce crippling uncertainty in rainfed agriculture through better water storage, many farmers in developing countries will face a losing battle with a more hostile and unpredictable climate.”
The IWMI study also advocates giving more weight to a continuum of small-scale storage options, citing strong evidence that when such measures are well planned, they can contribute importantly to local food security and economic growth.
Field studies in various semi-arid environments, for example, have proven the effectiveness of using small planting basins to “harvest” water, together with targeted application of organic or inorganic fertilizer.
In Zimbabwe, such basins have been shown to boost maize yields, whether rainfall is abundant or scarce, while in Niger, they have permitted three- or four-fold increases in millet yields.
But in some places, the results of major water storage initiatives have been uneven. In Ethiopia, for example, one study showed that groundwater wells and small dams reduced poverty by 25 to 50 percent.
But another analysis in the country’s Amhara region found that most of the approximately 4,000 water harvesting ponds constructed from 2003 to 2008 were no longer functioning, mainly because of poor site selection, technical failures and weak community involvement in maintenance.
“None of these options is a panacea,” said McCartney. “They all have pros and cons, which depend on their inherent characteristics, on the way they are planned and managed, and on the conditions at specific sites.”