جستجوی مقالات مرتبط با کلیدواژه « Bar Arye Watershed » در نشریات گروه « کشاورزی »

A review over the rainfall-runoff studies shows that, humid regions have received worth more attention than arid and semi-arid regions. So that, in this study, the rainfall-runoff process of an arid and semi-arid district, namely; Bar Arye Watershed with an area of about 112km2 and a mean annual precipitation of 307mm was simulated by using the spatially distributed rainfall-runoff model, WetSpa which has the ability to be connected to the geographical information systems. The period from 2003 to 2008 was applied for modeling. In the present study, according to Nash-Sutcliff criteria with the value of 0.69% for the validation phases it was indicated that the model has shown a good performance in modeling the rainfall-runoff. The rainfall-runoff coefficients of the observed and simulated values were equal to 0.59 and 0.57, respectively. This shows that the model has a good performance in estimating the values of runoff.

In this study, the WetSpa model was utilized to simulate the snow accumulation and melting processes in the Bar Arye mountainous watershed with an average altitude of 2225 meters above the mean sea level. The input data used in this study included daily records of precipitation, air temperature and potential evapotranspiration, covering the period of 2003 to 2008, as well as three types of maps, namely; land use, soil texture and topography maps. According to Nash-Sutcliffe assessment index values (0.67, 0.69) for the calibration and validation periods, the model could simulate the Bar Arye river flow with high accuracy. The results indicated that the temperature threshold for snow formation in this catchment was 0.11°C. According to the water balance components, it was indicated that the maximum amounts of equivalent snow water belonged to the months of December (29.25 mm) and January (37.94 mm), while the maximum snow melt values were observed during March and April , as 38.89 mm and 37.14 mm, respectively.