Determining soil erosion occurring from forest roads using WEPP-Road model within the Godrahav Creek Watershed in Artvin

Soil erosion is accepted as the most important environmental problem in Turkey. Besides agricultural areas, disturbed forests, burned areas, forest roads built for transporting harvests produced by forest management can also be listed as the most important sources for soil erosion. On the other hand, it is very difficult and costly to estimate or measure soil loss in a quick and reliable way. Therefore, the number of studies on using models such as USLE, SWAT, and WEPP to find out soil loss and/or sediment yield has been increasing and their application in the country is spreading especially in the last decade. However, since it is a rather new study subject, scientific researches using such models are quite limited in Turkey. In this study, using WEPP-Road Model, the estimation of sediment amounts produced by forest roads within the Godrahav Creek Watershed, a sub-watershed of Çoruh River Watershed, located in Artvin were investigated. For this purpose, based on parent material (granite and basalt) and forest management type (productive and coppice), 12 different forest roads were chosen. After dividing each road into 3 segments, values required by WEPP-Road model including slope, length, width, type, and surface of roads, traffic degree, fill slope and length, buffer zone slope and length, and rock content were determined and the sediment amounts were estimated by running the model. The results showed that 16.87 ton/ha/yr sediment were produced from the forest roads, the amount of sediment yield was reached to 746.15 ton/ha/yr when all the forest roads within the Godrahav Watershed were considered and the contribution ratio of all the forest roads among the total sediment produced within the whole watershed was 2.6%. In addition, both the parent material and the forest management type did not reveal any significant differences in respect to the produced sediment amounts. KeyWords: WEPP-Road, forest roads, bedrock and forest cover