Dams and irrigated plantations being built in Ethiopia will bring major changes to the flow of the Lower Omo River, which in turn will harm ecosystem functions and local livelihoods all the way to the river’s terminus at Lake Turkana in Kenya. More dams are planned for the basin that would compound the damages.
Here we outline some of the basic changes that can be expected as a result of these developments, and include resources on where to get more information.
The video below illustrates the hydrological risks the dam and plantations bring to the Lower Omo and Lake Turkana:
- The Gibe III reservoir is expected to start filling at the beginning of the next Kiremt rainy season (approximately May 2014); filling the reservoir will take up to three years. During this time, the river’s yearly flow will drop as much as 70%.
- The Gibe III will provide stable flows year-round that will enable the growth of large commercial agricultural plantations in the Lower Omo. The Kuraz sugar plantation and additional areas identified for cultivation could eventually take almost half of the Omo River inflow to Lake Turkana.
- These projects will cause a decrease in river flow and the size, length, and number of floods, which will be disastrous for downstream users. This is the first year in which runoff from the Kiremt season, which is vital for flood-recession agriculture, restoration of grazing areas, and fisheries production, will be almost completely blocked.
- Changes to the flooding regime will disrupt fish spawning cues and decrease productive habitat for fish in Lake Turkana and the river. Lake fish catches may decrease.
- Because the Omo River contributes almost all of Lake Turkana’s inflows each year, these developments could cause a big drop in lake water levels. Lake Turkana is projected to drop by about two meters during the initial filling of the dam. If current plans to create new plantations move forward, the lake could drop from 16 to 22 meters. The average depth of the lake is just 31 meters.
Climate change could worsen the water situation in the Omo. More extreme droughts and unpredictable precipitation patterns, combined with higher temperatures (which increase evaporation), could cause further stress to a region that already experiences extreme precipitation variability. There is evidence that there will be a drying trend and warmer temperatures.
- The Gibe III and associated irrigation projects will limit people’s mobility and ability to practice diverse livelihoods, which are important ways people in the region have adapted to climate variability in the past.
- The primary means of livelihood for about 500,000 people will be dismantled by the Gibe III and large-scale commercial agriculture. Conflicts over scarce resources are expected to increase.