The World Heritage Centre and IUCN have jointly decided to inscribe the Lake Turkana Parks heritage site into the List of World Heritage in Danger. This decision is awaiting approval by the World Heritage Committee during their 36th session at St. Petersburg, Russia, June 24 till July 6, 2012.
The decision is based on findings of the joint mission visit to Lake Turkana in March 2012 that identified the dangers posed by Gibe 3 Dam construction and associated irrigation fed plantations and dams in the Lower Omo basin, oil exploration, pressure from poaching and livestock grazing and impacts of other larger developments in northern Kenya. The joint team concludes that these dangers are severe enough to place the Lake Turkana heritage site in the danger list.
Gibe 3 Dam and associated irrigation plans is the biggest danger to the lake. Gibe 3, according to the official Ethiopian website for the project, is 50% complete and it will take 3 years to fill up once completed. During this 3-year period, the water levels on Lake Turkana will reduce by 1.65 to 4m above normal flactuation levels according to joint team's models. But this is not the biggest problem. According to the team's assessment:
After filling is complete and if no water would be extracted from the Omo river downstream of the dam, normal river flow volumes would return to the lake, but it could take 12 years for the lake to return to its equilibrium level. Thus the impact of filling may last 15 years in total. The drop in water levels will move the shoreline of the lake significantly, particularly in the northern part of the lake where two components of the property are located (estimated at 2-3 km minimum at a drop of 1.65 m). This significant drop in lake levels could result in increased salinity and in likely impacts on wildlife which depends on the riparian flood plains and wetland habitats along the lake’s shore for food and breeding as well as on fish stocks as a result of the drying out of major fish spawning areas, such as Ferguson’s Gulf and the delta of the Omo River)
There will also be direct impacts of reduced oscillation due to the dams flood control capacity. Cummulative irrigation projects in the Lower Omo will complicate this matter further. For instance "the Kuraz sugar development is already under construction and there are plans to convert 278,000 ha of land along the river to sugar plantations and other agricultural developments using irrigation. The African Development Bank study cites the Omo-Gibe basin master plan in which irrigation developments by 2024 would use 16% of the basin’s water and calculates this would lead to a reduction in lake level of 8.4 m. This is a significant hydrological change to the lake."
The World Heritage and IUCN team cites many other reasons for inscribing Lake Turkana into the danger list. You can read the section on Lake Turkana in their report which can be downloaded here. Lake Turkana is on page 11 of this PDF document.