Determination of water erosion in Kowsar catchment area and evaluation of Gabion structures in its control

Abstract

Water erosion is one of the problems in the country that reduces soil fertility, environmental degradation, food security threats, and the filling of dams’ reservoirs. Therefore, the use of sedimentation control methods such as Gabion structures is considered important. The purpose of this study was to evaluate the geotechnical structures of Kowsar watershed in the Khuzestan province with an area of 64.81 km2, located in the longitude 48°25′36″ to 48°33′27″ east, and the latitudes 32°40′54″ to 32°45′38″ north. In this basin, 279 structures with a volume of 13,374.35 m3 were studied in 2017. The results of this study showed that the specific erosion and sediment production in this basin were 5742 m3 km−2 and 145,130 m3 year−1. Based on the area of each of the sub-basin and based on PSIAC factors, it was found that 76.12% of the basin area was in the very erosive class, 0.3% in the erosion class and 23.58% in the moderate erosion class. In general, it was expected that 13,442.99 m3 of sediment would be inhibited in this sub-basin, but due to the destruction of some structures, the trapped sediment rate was determined to be 79,421.8 m3. Therefore, the structures constructed in the Kowsar basin with an efficiency of 59% had a relatively good ability to contain sediments in this basin.