Identification of erosion hot spot area using GIS and gully contribution for reservoir sedimentation in the case of Abrajit reservoir, Upper Blue Nile Basin, Ethiopia

• Published in: Sustainable water resources management Vol. 8; no. 4
• Main Authors: Kifelew, Mekash S., Mesalie, Roman A., Shumey, Eusman E., Fikadie, Fitamlak T., Worku, Tadege A., Kassahun, Fentahun A., Damtie, Menwagaw T., Jumber, Marshet B., Alem, Belachew B., Asitatikie, Asimamaw N., Hishe, Teka G., Bereda, Kidusie T., Alemnew, Habtamu N., Wubneh, Melsew A.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.08.2022; Springer Nature B.V
• Subjects: Bottom trawling; Dams; Development Economics; Dredging; Earth and Environmental Science; Earth Sciences; Geographical information systems; Gullies; Gully erosion; Hot spots; Hydrogeology; Hydrology/Water Resources; Identification; Natural vegetation; Original Article; Plant cover; Remote sensing; Reservoir sedimentation; Reservoirs; Runoff; Sediment; Sediment load; Sediment yield; Sedimentation; Sedimentation & deposition; Sedimentation rates; Sediments; Siltation; Soil erosion; Sustainable Development; Sustainable use; Vegetation cover; Water Policy/Water Governance/Water Management; Watersheds; Ethiopia; RUSLE; Abrajit dam; Short-term gully erosion rate; Erosion hot spot area; Upper Blue Nile Basin
• ISSN: 2363-5037; 2363-5045
• DOI: 10.1007/s40899-022-00680-7

In Ethiopia, dams are adversely affected by sedimentation due to soil erosion from the watershed area. Thus, this study was conducted on the Abrajit watershed and its reservoir in east Gojjam, Amhara region, Ethiopia. The general objective of this study was to the identification of erosion hot spot areas and estimation of watershed sediment yield to the reservoir. For estimation of annual soil loss from the watershed, the RUSLE model integrating with GIS and remote sensing was used. The total soil loss rate was computed spatially by overlaying the five grid layers of RUSLE factors over the Abrajit watershed using Arc GIS. The average annual soil rate of Abrajit was 4.06 tons/ha/year. In addition, from least to the maximum value, yearly soil loss in the watershed ranged from 0 to 66.75 tons/ha/year. RUSLE model has limitations to assess erosion from gullies, besides the reason that gullies are considerably affecting siltation processes, further watershed gully data were collected. The sediment load contributed from the watershed to the reservoir was high. But, only natural vegetation cover is available to reduce sediment entry to the reservoir by runoff. It is implying that this small dam is extremely affected by a high rate of sedimentation. This calls for periodic dredging of deposited sediment in a small dam to recover impounding capacity for sustainable use of the water.