DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 11-12/2017 str. 28 <-- 28 --> PDF |
WEPP Input Data Files Ulazni podaci projekta WEPP To describe hillslope geometry, meteorological characteristics, soil properties, and ground cover, four input files including slope, climate, soil, and management files were produced. The slope file consisted of necessary hillslope parameters such as slope gradient, shape, width and orientation along its length. TOPAZ was used to produce sub-catchment profiles based on DEMs (30 m x 30 m). Then, the soil and management data are assigned into each sub-catchment so that spatial variability between sub-catchments can be represented. To generate climate data, „Rock: Clime” application in WEPP was used to access database of PRISM (Parameter-elevation Regressions on Independent Slopes Model), which estimates precipitation and temperature based on orographic effects (Daly et al., 1994). „Rock: Clime” is able to read and adjust the inputs of monthly average precipitation and temperature values (Elliot and Hall, 2000). Climate data for the study area were first obtained from the weather station in the city of Kahramanmaras, and then entered into the WEPP as a climate file of CLIGEN. The soil data, which are used in GeoWEPP to predict erosion, include soil texture (sand, dust, and clay ratio), organic matter content, and cation exchange capacity values. These soil properties were determined based on field study and laboratory analysis. Soil sample plots were taken from different bedrocks (sandstone and limestone), elevation levels (1250-1650 m and 1650-2050 m) and aspect groups (north and south), according to „Factorial Trial Design” approach. Besides, disturbed and undisturbed soil samples were taken from two different soil depth classes (0-20 cm and 20-50 cm). Management file data (i.e. plant height, vegetation surface ground cover, grazing periods, etc.) were obtained by field studies and then entered into the model. The management file was generated for each sub-watershed for every year of simulation. Then, the land cover layer was generated based on management file using GIS tool. RESULTS AND DISCUSSION REZULTATI I RASPRAVA Physiographic and climatic factors – Fiziografski i klimatski čimbenici In this study, the soil loss, sediment yield, and runoff values for a sample watershed in Kahramanmaras were predicted by using GeoWEPP model. The study was conducted in |