جستجوی مقالات مرتبط با کلیدواژه « pcraster » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

Accurate estimation of a watershed response to rainfall events plays an important role in its soil and water resources management as well as civil works design within watersheds and over or around its downstream rivers. Nowadays, due to improvement in our knowledge and understanding from watershed systems and enhancement in hardware and software technology as well as facilitation in learning and application of these technologies, researchers prefer to design and apply their required models themselves according to their aims and availability of data. The aim of this research is to develop a spatio- temporally distributed model within PCRaster GIS and programming environment to achieve a better representation of watershed processes at a small scale agricultural micro-watershed. In this study, based on the available local data, an event based rainfall – runoff hydrological simulation model was developed within PCRaster GIS and programming software and its performance was evaluated using observed data from a 27.6 ha agricultural micro-watershed discharging to the Shahrak – Behzisti residential area in the Gorgan city. This is a tightly coupled GIS model. During the research period, only two rainfall events leading to runoff generation occurred on 2/11/2014 and 16/9/2015 which were, respectively, used for calibration and validation of the model. Statistical comparison of the simulated and observed hydrographs of the rainfall - runoff events on 2/11/2014 and 16/9/2015 showed the correlation coefficients of of 0.69 and 0.65 and Nash-Sutcliffe criteria of 0.5 and 0.51, respectively. The results indicate that the developed model has a good performance at simulating rainfall-runoff processes during events.

Modeling of hydrological processes provides appropriate information for watershed management through a deep and comprehensive insight on watershed systems. In this research a daily basis distributed water balance model for the Chehelchay watershed in the Golestan province in north east of Iran has been developed using the PCRaster GIS and dynamic modelling language. Various components of the watershed water balance including precipitation, snowmelt, evapotranspiration, soil moisture, surface runoff, interflow and baseflow have been simulated. Total discharge has been obtained by aggregating surface runoff, interflow and baseflow. Calibration of the developed model has been carried out by observed daily discharge during 2007-2008. For validation, the observed data of 2004-2006 period has been used. The Nash-Satcliffe efficiency criterion has been used to evaluate the model results. The results indicated that the value of the Nash-Satcliffe coefficient was 0.7 and 0.5 for the calibration and validation period, respectively. Since a Nash-satcliffe value for both the calibration and validation period is greater than 0.36, it can be concluded that the developed model has a relatively good capability to simulate the Chehelchay watershed discharge. Given that the results are suitable, different components of the water balance of the Chehelchai watershed have been calculated. The model results showed that the runoff coefficient of the watershed is 19.1 percent which is similar to its observed counterpart of 22 percent. The results of the developed model were also compared with the results of WetSpa model in this watershed.