DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 11-12/2017 str. 29 <-- 29 --> PDF |
Keklik watershed covered by only rangeland. Physiographic and climatic factors (slope, aspect, soil, landuse, and climate) of the study area were determined to provide WEPP input data files required for the prediction process. The topographic conditions are important in terms of erosion and surface runoff in watersheds (Yuksel et al., 2007). Especially, average ground slope plays important role in formation of surface runoff. The results indicated that the average slope in the watershed was 45.7%. Based on the digital slope map of the study area (Figure 3), about 84.4% of the watershed was classified as high, very high, and steep slope (Table 1). This topographic condition increases water erosion and sediment delivery (Figure 4). The aspect of the study area was mostly south aspect (55.7%), followed by north (31.5%), west (10.9%), and east aspects (1.9%). In general, the watershed represents the typical climate and vegetation features of southern aspects. The soil loss and runoff is usually higher in southern aspects since vegetation cover density is potentially less than that of other aspects (Balci, 1996). The results from laboratory analysis and field studies indicated soils are usually located on sandstone and limestone bedrocks. Soil textures characteristics formed from these rocks were sandy loam, clay, sandy clay loam, and loam. Geological and pedological properties of soils affect soil losses (Butorac et al., 2009). The watershed can be subject to surface runoff risk due to lower infiltration capacity of clay soils. It was also found that the average dispersion ratio (76%), as one of the erodibility indices, was greater than the boundary value of 15% (Nipon and Kasem, 1969). Thus, it can be concluded that the study area of soils in Keklik watershed is generally susceptible to erosion. Climate data including average precipitation and temperature values, obtained from local weather station, were 976.50 mm, and 15.2 °C, respectively. Since most of the precipitation in the watershed occurs as snow, rainfalls and melted snow during spring season results in high runoff effects. Management data obtained by field studies indicated that plant height and vegetation surface ground cover was found as 30 cm (maximum) and 16%, respectively. The grazing periods in the watershed was from April to mid of November. Sediment Yield and Runoff – Produkcija nanosa i otjecanje Sediment yield and runoff values were computed once generating WEPP input data files using CLIGENE, TOPAZ, |