Gully erosion is a widespread problem in the Borana plateau. Gullies are the main pathway for sediment accumulation in community ponds, especially during heavy rains, which reduces pond capacity. Sediment movement in gullies can be substantially reduced by installation of sieve structures that slow down water flows and allow sediment to settle out of suspension. Sieves can be easily constructed from trees by community labour at low cost. The community should develop a landscape-level plan and follow a suitable sieve design. Project Kalo collaborators have demonstrated that a series of sieve structures down a secondary gully in the Dikale pond enclosure can effectively trap sediment. The main gullies feeding ponds have large catchments generating rushing flood-waters that destroy sieve structures downstream. The appropriate, comprehensive treatment is to begin at the gully head with brush barriers to steer overland flows away from the gully, and branch layers to protect the head cut itself. When gully head treatments are accompanied by a series of sieves in the main channel, gully erosion can be arrested, gully floor and walls revegetated and sediement captured. This approach has been validated by OARI colleagues at the Kobo Watershed gully and on a degraded portion of the Beke pond catchment. It has also proven successful in small channels at Dikale and other enclosures.
Tadele, D., J. Doyo, B. Eba, D. Teshome, B.E. Norton, and D.L. Coppock. 2015. Sieve structures to control gully erosion on the Borana Plateau, Ethiopia. Research Brief-24-2015, Feed the Future—Adapting Livestock Systems to Climate Change, Colorado State University, Fort Collins, CO, USA. 5 pp.