Evaluation of technical standards of physical soil and water conservation practices and their role in soil loss reduction: The case of debre mewi watershed, north-west Ethiopia

Abstract

Soil and water conservation (SWC) measures had been implemented for the last four to five decades to reduce the severe soil erosion problem in north-west Ethiopia. A study was conducted at Debre Mewi watershed, north-west Ethiopia, Upper Blue Nile Basin, to evaluate the technical standard of the implemented SWC measures and their role in reducing soil loss using the RUSLE model, farmers’ interviews, transect walk, field observation and direct measurements. Soil bund, fanya juu, stone check dam, gully reshaping and artificial waterways were evaluated based on vertical interval and width between bunds, gradient and length of bunds, embankment height and compaction and size of artificial waterway parameters. As a result, most of the gully treatment designs and waterway layouts fail to meet the standard. Most of the SWC structures constructed in the study area didn’t meet vertical interval, bund length, bund gradient, embankment compaction and height standards, which reduced the effectiveness of the measures in reducing soil erosion.SWC measures technical standards deficient construction and management was found to be an important cause of soil erosion. Although based on modelling, soil erosion after SWC applications is reduced, but is still higher than the tolerable soil loss rate. Increased effort in guideline improvement and implementing SWC measures based on their technical standards is required to manage soil erosion.