DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 5-6/2021 str. 47 <-- 47 --> PDF |
Evaluation of the effects of some watershed characteristics on water and suspended sediment yield in agricultural and forest dominated watersheds Procjena utjecaja nekih značajki sliva obilježenih dominantno šumarstvom i poljoprivredom na otjecanje vode i produkciju suspendiranog erozijskog nanosa Tark Çtgez, Refik Karagül, Mehmet Özcan Summary Topography, geological structure and land use play a determinative role in the streamflow and total suspended sediment yield of watersheds having similar climate, soil and vegetation characteristics. In order to facilitate sustainable water resource management and effective land use planning, there is an increasing need for research investigating the effects of these factors. This study was carried out in forested and agricultural dominated subwatersheds of the Big Melen watershed in the Western Black Sea Region of Turkey. Hazelnut plantations are grown on most of the agricultural areas in both watersheds. The forested watershed has a steep topography and its geological structure consists of sandstone-mudstone and sedimentary rock. The agricultural watershed area is larger and unlike the forested watershed, there is argillaceous limestone in its geological structure. The precipitation, streamflow and total suspended sediment yield in the watersheds were measured for two years. The total precipitation of the study area over the two years was 2217.3 mm. The water yield of the forested watershed was 867.6 mm, while that of the agricultural watershed was 654.9 mm. In the two years, the total suspended sediment transported from the forested watershed was 19.51 t ha-1 and from the agricultural watershed 7.70 t ha-1. However, except for the high values measured after an extreme rainfall event, the unit surface suspended sediment yield of the agricultural watershed was found to be higher than that of the forested watershed. These findings showed that watershed characteristics such as slope, geological structure and rainfall intensity may be more effective on the streamflow and total suspended sediment yield of the watersheds than land use. Key words: Big Melen watershed, land use, suspended sediment yield, watershed characteristics, water yield INTRODUCTION UVOD Many factors such as precipitation, land use, topography, geological structure, and soil are effective on the streamflow and sediment yield of watersheds (Zhang et al., 2010, 2014; Ebabu et al., 2018). Accordingly, it can be said that land use, geological structure, and topography are the determinative factors controlling precipitation-streamflow relationships for watersheds that have similar vegetation types, precipitation, and soil characteristics. When the effects of one of |