Abstract:
Water resources management within a basin has always been challenging. With the continuous increasing demand and a finite supply, an effective management of water resources is needed to meet these demands in a sustainable manner. Land management practices can alter the hydrological system as land-use change has a direct effect on hydrologic processes. Korang River catchment is an important watershed in Margalla Hills. Rawal Dam is first Dam in Pakistan constructed on Korang River in 1969. The Rawal Lake located in Margalla Hills National Park Islamabad. However, sustainable water resources management has become a challenging issue in this catchment in recent years. Land-use change such as deforestation followed by inconsiderate highland agricultural activities and rapid urbanization have already affected hydrological regime of the Korang River catchment. Furthermore, rising pressures to meet urban, industry, agricultural and environmental demands will have an impact on available resources. Proper management of this resource is important to meet the water demand and sustainable future water use. Water resources modelling of a catchment can provide essential information required to assess the impact of land use on available resources. In this study hydrological modelling technique will be used to evaluate effects of land use change on Korang River catchment hydrologic response and the spatial configuration of the developed areas in Margalla Hills over the time. The study will also evaluate impacts of land use change in the hydrological parameters of the Korang River catchment using Soil and Water Assessment Tool (SWAT). Land use maps of years 1992, 2000 and 2013 were used to identify the land management practices occurring over the years. Unsupervised classification was performed and six land use classes were formed. After calibration and validation of the data in SWAT model simulated discharge was obtained which showed a significant decrease in discharge over the years. Model simulation was done and it showed increase in water yield and runoff but a decrease in ground water and lateral discharge. Furthermore three land use scenarios were created to predict the future land use impacts on the water yield.
