Estimation of Soil Losses in Capakcur Watershed (Bingol, Turkey) Using RUSLE Method and Comparison of Predicted Soil Losses with Sediment Yield

The present study aimed to determine the total and net erosion in the Capakcur watershed, which has a high erosion risk. Accordingly, annual soil loss in the Capakcur watershed was estimated using RUSLE method. Net erosion was determined directly by measuring the monthly flow rate and sediment concentrations of the Capakcur stream, which originated from the Capakcur watershed and flowed into the Murat River throughout 2019. Estimated soil loss in the Capakcur watershed was 96916.20 ton yr(-1), and the amount of soil transported from the Capakcur stream was 68656.09 ton yr(-1). Sediment delivery ratio (SDR) was calculated as 0.78. This ratio was well above the average SDR of Turkey (0.23). Topographic factors such as slope length and degree, rainfall, and low vegetation cover ratio in the watershed are the main causes of the high SDR. Due to the high SDR, the fertile surface soil layers of lands in the basin are carried to the streams. This causes both decrease in fertility in soils and pollution of the limited freshwater resources. In order to improve vegetation and management practices in the watershed, soil protection practices such as afforestation and terraces, wire cages and stone walls in gullies should be increased.