LONDON (Thomson Reuters Foundation) – New water management strategies will be needed to ensure sufficient water supplies in West Africa’s Volta River Basin, a region likely to be hard hit by climate change, researchers say.
Around 24 million people in Ghana, Burkina Faso, Benin, Ivory Coast, Mali and Togo depend on the Volta River for domestic water, agriculture and hydroelectric power. Current water management practices are unlikely to keep up with projected changes in temperature and rainfall over the next century, found a new study by the International Water Management Institute (IWMI) and its partners, which used climate models to work out how climate change might affect the region.
Researchers based their study on the most moderate of four scenarios outlined by the Intergovernmental Panel on Climate Change (IPCC), which explore different degrees to which greenhouse gas emissions might change in the future, in combination with technological interventions to bring emissions down.
The model predicted “very significant changes which will have serious consequences for the rural poor, food security and economic growth in the riparian countries,” the study said. “Future water resources development in the basin requires integrated planning that bolsters resilience and water security,” it added.
Matthew McCartney, lead author of the study, noted that the study results are drawn from a single scenario, “and so are at best indicative and not absolute”. But emissions have already increased more rapidly than even the worst-case scenarios would indicate, and climate change experts are now more certain that the global average temperature is likely to increase by as much as 3.6 degrees Celsius, and that rainfall variability will continue increasing, he added.
These two trends already pose challenges to farmers who must make decisions about when to plant their crops, for example. The study also indicated that shifts in temperature and rainfall could reduce the power generated by hydroelectric projects in the basin, even below current levels.
At the same time, the study highlighted how several adaptation measures could help farmers protect themselves from less predictable rain patterns and ensure the water supply of the Volta River Basin can keep up with growing demands.
The most important of these will likely involve building the capacity of smallholder farmers to manage their water supply, McCartney said. Most farming in the region is rain-fed, so switching to irrigated agriculture would ensure a more predictable water supply.
There is also a need to consider the smartest ways to collect and store irrigation water. “Groundwater makes a lot more sense than using river flow because it will evaporate less,” McCartney said. “One thing we suggested was thinking about how to recharge groundwater aquifers as a way of storing water, so farmers with individual wells can access it when they want.”
Farmers could also collect rainwater on their rooftops or in a small pond, for example. That extra supply could be useful during dry spells or for giving their crops a little extra water when needed.
McCartney said that, on a broader level, water management around the Volta River Basin must become much more cohesive. “Right now all the countries in the basin do their own thing,” he said. “When they want to build a dam, they build it without asking and without any context.”
Dams in particular are a significant problem, because they sometimes force people to relocate from areas where the reservoir floods, and change the river flow, negatively impacting fisheries downstream. Much more consideration should be given to the effects of large-scale infrastructure on river flow and the people whose livelihoods depend on it, McCartney said.
There is a Volta Basin Authority responsible for this, but “it hasn’t got much clout,” McCartney said. “In reality it needs to be much more powerful,” he added.
One of the study’s key recommendations is that countries around the Volta River Basin need to work together to manage water resources.
That means helping farmers who may not have the money or knowledge to adopt a new water strategy, looking into wind or solar energy to supplement hydropower, and exploring innovative ways to store water. “It’s about making the best use of the water across the whole region,” McCartney said.
Erin Berger is a Thomson Reuters Foundation intern, writing on climate change issues.