Abstract

Zerihun Asad, Dametew Adem and Abdulaziz Farah

A study was carried out at Lake Haramaya Catchment (5032 ha) to evaluate soil erosion, sedimentation and conservation practices. The catchment has experienced severe degradation due to intensive cultivation, deforestation, unwise utilization of land and water resources which lead to the onset of soil erosion. The Gumbel's Method and MUSLE were employed to estimate the peak flood and catchment sediment yield respectively. SWAT was used to delineate the catchment and to analyse the catchment slope, soil and land uses. Besides, interview and field observation were carried out to collect data regarding the effects of soil erosion and status of existing conservation measures. The average annual soil loss from the study area estimated is to 24.315 ton/ha/year resulted due to the high rainfall erosivity in the area. Moreover, the results showed a direct relationship between rainfall and sediment yield. With regard to the method of soil and water conservation practices, biological conservation measures like mulching and mixed cropping are widely implemented with almost zero or negligible engineering measures. Small mechanical/engineering measures that could better hit the target are not considered. Generally, soil erosion of the catchment is high and integrated watershed management is needed to minimize the erosion problem.