Impacts of catchment restoration on water availability and drought resilience in Ethiopia: a meta‐analysis
The coupled land degradation-drought impacts have been central challengesto ecosystem functions and livelihood of farmers in Ethiopia. As a response, catchment restoration initiatives have been implemented since 1970s. The objective of this paper is to analyze the outcomes of the catchment restoration initiatives on water resources and drought resilience, using metadata from 106 peer reviewed journal articles comprising 361 paired-catchment case studies. The study shows exclosure, fanya juu and soil/stone bunds are major soil and water conservation (SWC) practices introduced to restore the degraded catchments in regions prone to land degradation (with a high value for degradation coefficient). Runoff was less in treated catchments (97±29 mm/year) than in control catchments (168±77 mm/year) (n=217, p<0.0001).
A paired t-test also shows a lower runoff coefficient exists in the treated (13±10%) catchments than control catchments (25±15%) (n=57, p<0.0001). The conjunctive uses of SWC measures enhanced water infiltration into vadose and aquifer zones. These measures are effective in reducing unproductive water losses. Moreover, the water level in shallow wells raised from a depth of 18±11 to 2±1 m after catchment management.
In the dry season, well-functioning catchments promoted upstream-downstream hydrological linkages. Such consistent water flow reduced hydrological, agricultural and socioeconomic drought effects in treated catchment. To conclude, catchment restoration practices at the degraded landscape have twin goals: enhancing freshwater availability and building drought resilience. We suggest scientists, donors and managers to work on spreading of restoration efforts to other degraded landscapes to improve water yield in the face of climate variability.
Meaza, Hailemariam; Abera, Wuletawu; Nyssen, Jan.