Determination of soil losses caused by the streambank and gully erosion in olur micro watershed within the Çoruh river basin

In our country, every year billions of cubic meters of fertile topsoil are eroded and transported to seas and lakes due to erosion. When considering the soil formation process that takes thousands of years, it becomes very clear how important and valuable this loss is. Soil erosion caused by water is considered to be the type of erosion that erodes the soil the most and causes loss of productivity. Along with surface erosion, greater soil losses can occur due to channel and gully erosion. In this study, soil losses due to gully and channel erosion (1st and 2nd order streams) were measured in the Olur Micro Watershed for a total of two years using the "erosion pin method". While the average amount of streambank and gully erosion in the first year of the two-year study period was 10.34 cm/yr, it was 2.77 cm/yr in the second year of the study, and at the end of the two years, the total erosion amount was calculated as 13.11 cm. According to these data set, it was seen that the soil losses in the first year were much higher than the soil losses in the second year of the study. The main reason for this is that the total amount of precipitation (48.6cm) in the first year was much higher than in the second year (34.9 cm). While the average soil losses in the streambanks and gullies in the first year of the study was 256.8 tons/km/yr, it was 77.3 tons/km/yr in the second year, and the average of these two years was 167.05 tons/km/yr. While the total amount of erosion in the 1st order streams was 3421 (28%) tons/yr, it was calculated as 1002 (8%) and 7857 (64%) tons/yr in the 2nd order streams and the gullies, respectively, with the longest length in the whole watershed. In this context, it is of great importance and priority to pay more attention to the gullies in soil conservation measures to be carried out in the Watershed.