Water transfers between river basins
Interbasin transfers threaten world’s freshwater resources
But water transfers aren’t always the answerWater transfer schemes attempt to make up for water shortages by constructing elaborate systems of canals, pipes, and dredging over long distances to convey water from one river basin (the donor basin) to another (the recipient basin).
Under certain circumstances, large-scale water transfers fulfill an important role in providing water to those in need, but overall their benefits are doubtful.
Water transfers seriously impact the environment of the donor basin. They create or escalate threats to critically endangered species, Ramsar-listed wetlands, and protected areas. Dams constructed on the river from which water is taken can devastate its ecology, disrupting environmental flows and blocking migrating fish.
Water transfer schemes compromise rivers’ ability to provide food and water. Even when "only" 10 to 15% of water is taken from one basin, it can cause droughts in both basins in times of little rainfall.
Economic and human costs
Economic benefits generated in the recipient basin often come at the cost of those living in the donor basin.
Some projects have displaced entire communities. People whose livelihoods depend on the donor basin have not always been consulted on how they will be affected. In the past, this has created social conflicts between the donor and recipient basins and governments.
And while a water transfer scheme is designed for their benefit, residents of the recipient basin also face negative consequences.
Cost overruns are common and planned benefits may fall short. Without massive government subsidies, farmers in areas receiving water could pay as much as US$1 per cubic metre, making their produce more expensive locally than that available on world markets and threatening their livelihoods.
Down the drain: wasted water and water transfersIn many cases, water use in the recipient basin is not evaluated prior to the construction of a water transfer project. This contributes to the continuation of unsustainable water use practices and, over time, increases the thirst for more water.
For instance, agriculture — which accounts for 70% of the world's accessible water use — wastes 60%, or 1,500 trillion litres, of the water it uses each year.
But improvements are possible. In the case of cotton, one of agriculture's most water-intensive crops, water savings of up to 70% are achievable by switching to sprinkler or drip irrigation systems. If a water transfer scheme is built, there is less incentive to move to such practices.