Erosion-control interventions associated with pond-catchment rehabilitation on the Borana plateaus, Southern Ethiopia

Among the major problems of Borana pastoralists are scarcity of potable water inside dry season and gully erosion in a widespread on the Borana plateau. Gullies are the main pathway for sediment accumulation in community ponds, which reduces pond capacity. Ponds are therefore a critical source of water during dry seasons the Borana rangelands. However, most ponds rapidly fill with sediment from eroding catchments after rainfall events and hence, their water holding capacity gradually get reduced. Much work is then required each year from the communities to remove sediment manually. Erosion of pond catchments is the consequence of uncontrolled grazing that causes heavy grazing and trampling by livestock. 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. Yabello researchers have demonstrated that a series of sieve structures down a secondary gully in Bunaka and Liban Jatani pond that effectively trap sediment. When gully head treatments are accompanied by a series of sieves in the main channel, gully erosion can be arrested, gully floor and walls re vegetated and sediment captured. Overall, protection of grazing land from livestock reach for only one year led to a 55.45% increase in ground cover. Similarly, increases in cover tended to be greater (118.1 % more) at Liban Jatani pond that had less cover at the beginning when compared to Bunaka pond. Protection from livestock grazing led to substantial increases in ground cover. Within the Liban Jatani pond enclosure, ground cover steadily increased at each sampling period by 7.1% in June 2019, 11.13% in November 2019.