As Kenya gears to move away from rainfed agriculture and invest heavilly in alternatives mainly irrigation, reports have raised the red flag saying at long run such a move may cause more harm than good. A report on a study done by United Nations Environment Programme (UNEP) and released in 2012 indicates that heavy usage of water from river and lake for agricultural use has a negative impact on ecosystems.

Recognising the valuable services provided by ecosystems such as wetlands and forests - and not only focusing on water productivity in agriculture - can improve livelihoods and help meet the rising demands on the world's water resources in a sustainable way, according to a new report from the UNEP.

Services provided by forests, mangroves and other ecosystems should be taken into account when managing water use, says a new report from UNEP. A broader view of water productivity will be needed if demands on water resources are to be met, and global food security ensured, argues the study. Kenyan government is considering investing heavilly into alternative ways of food production such as irrigation. This follows chronic drought that has made the rainfed farming ineffective.

The UNEP report, entitled Releasing the Pressure: Water Resource Efficiencies and Gains for Ecosystem Services, which was produced by researchers at the Stockholm Environment Institute (SEI), urges policymakers and resource managers to shift from the traditional focus on water productivity per unit of agricultural yield ("more per crop drop"), to a broader view of the concept, which would include ecosystems services.

“There are growing concerns over the loss and degradation of aquatic habitats such as wetlands, lakes and river systems, in part due to the syphoning off of these precious resources to agriculture and energy developments;” said Achim Steiner,Under Secretary General and Executive Director UNEP.

Such an approach would take into account water regulation and purification, pollination, erosion control and other ecosystems services performed by wetlands and forests. These water-dependent services, and the communities that rely on them, can be adversely affected when water is siphoned off from rivers or streams, or drained from marshes, for agricultural use, reads the report in part.

“The quantity, timing, and quality of water flows in landscapes need to be sustained to improve human well-being reliant on landscape ecosystem services,” it added. The study uses several case studies among them one case study done in Cameroon.

“The Waza Logone Floodplain in camerroon lies in the far northern portion of Cameroon, and is one of the most biodiverse portions of the Sahel. Historically, the Waza Logone was a seasonal wetland that was flooded by the Logone River, and the seasonal rivers Mayo Tsanaga, Mayo Boula, and Mayo Vrick. However, due to extensive upstream irrigation, the flooding has been reduced by nearly 30% relative to 1970 flow rates,” states the study.

This has severely reduced wetland function and the associated benefits to local and regional livelihoods and incomes. A quarter of a million people live in the region, and the lack of seasonal flooding of the Waza Logone region has had significant consequences, including: agricultural Losses from lack of irrigation, loss of 90% of fisheries, decrease in dry-season pasture, loss of grasses used in cultural and livelihood activities, and loss of surface water for livestock watering and transport.

Farmers will need 19 percent more water by 2050 to meet increasing demands for food, much of it in regions already suffering from water scarcity, according to fourth United Nations World Water Development Report.
Agriculture already accounts for 70% of freshwater use and with the UN Food and Agriculture Organization says that food output must increase by 70 percent by 2050 to feed a world population increase by 2.3 billion to 9.3 billion by then. A quarter of world farmland is “highly degraded” by intensive agriculture that has depleted water resources, reduced soil quality or increased erosion, according to the agency.

Farming is causing a large stress of water in some parts of the world such as Middle East and Syria. Saudi Arabia is reducing grain production to avert potential water crisis and already encouraging companies to lease large tracts of land in Africa for production of grains, blooemberg quotes the report.
“India is growing maize, sugarcane, lentils and rice in Ethiopia, Kenya, Madagascar, Senegal and Mozambique to feed its domestic market,” it states.

By acquiring rights to grow crops in other countries it implies they acquire right to use their water in the process spreading water stress to other regions too.