Estimating and Mapping Soil Loss Rates using RUSLE Model for Soil Conservation Planning in Katar Watershed Central, Ethiopia

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Conservation, GIS, Hot Spot, Katar Watershed, Pioriritization, Remote Sensing, RUSLE and Soil Erosion
Amare Nigussie; Tadesse Hunduma Banja
The rate of soil erosion is severe in the highlands of Ethiopia. Identification of hot-spot areas of erosion and prioritizing areas of intervention is extremely important for reducing further degradation, reclaiming the degraded areas and improving the land productivity of the watershed. The objective of this study was to estimate soil loss rates in the Katar watershed, Central Ethiopia. The Revised Universal Soil Loss Equation (RUSLE) integrated with satellite remote sensing and geographical information systems (GIS) as a useful tool for conservation planning was used. Mean annual precipitation, soil map, 30m digital elevation model, land-cover and management map, land use types and slope length and slope steepness were used to determine the RUSLE values. Based on the level of soil erosion rates, the study area was divided into seven priority categories for conservation interventions. Mainly the practice of removing plant residues, poor physical soil conservation measures, lack of conservation practice and ploughing the land several times may be the reasons for the high soil loss in the study area. Moreover, the total soil loss in the study area was 7,795,936.31 metric tons per year from 316,762.2ha of land with mean soil loss of 24.61 t/ha/yr. The very high soil loss was observed in steep dissected to mountainous terrain of the upstream of watershed. Out of the 23 SWs, only six sub watersheds SW6, SW1, SW2, SW11, SW7 and SW3 were existed under very high erosion rate with mean soil loss ranges from 33.25 to 39.81 t/ha/yr which cover 23 percent of the total land and high soil loss rate was estimated in twelve sub watersheds (13, 9, 17, 12, 10, 15, 14, 5, 8, 18, 19 and 16) which are spatially located at upstream and middle parts of the watershed with mean soil loss ranges from 20.59 to 28.2 and covers 51 percent of the total land.The watershed has a range of the erosion severity classes of extremely severe, very sever and sever. The steep slopes of upstream watershed have contributies high soil loss is more critical and should be given first priority during intervention measures. The poor vegetation cover management and the lack of conservation practice of the area should be improved to reduce the high soil loss throughout of the watershed.