Abstract:
Climate change is expected to affect Pakistan's hydrologic resources. The impact of climate change has always been very important for water resources in the world. Generally, the climate changes are considered in terms of global warming i.e. increase in the average temperature of earth's near surface air. Climate changes can strongly affect the river flows in Pakistan and the hydrological processes are notably influenced by, climatic changes, such as precipitation and temperature variation. The Khanpur watershed in Pakistan has a high spatial changeability of precipitation attributable to extremely undulating surface topography and complex interactions between the inflow, precipitation and temperature. The climate data i.e. precipitation and temperature (maximum and minimum) is obtained from the meteorological stations adjacent to the study area Islamabad, Murree and Khanpur while the inflow data of Khanpur dam was obtained from Water and Power Development Authority (WAPDA) for years (1988-2016). The SRTM DEM of 90-meter resolution of the Khanpur watershed was required to carry out the research, ArcGIS software version 10.2 is used for the delineation of the catchment area, the Minitab 18 and Microsoft Excel 2013 is used for finding the statistical analysis and graphical representation of the data. The results revealed that mean precipitation over the past 28 years at Khanpur, Islamabad and Murree station is (1026.0, 1244.4 and 1726.54mm) while mean temperature at Islamabad and Murree station is (28.9 and 18.10 °C). Mean inflow at Khanpur over the past years is 8.667 m3/sec, it was evident from the study that the overall trend of precipitation at Khanpur, Murree and Islamabad station is 'changing the increasing trend of precipitation is observed at Islamabad and Khanpur station while decreasing trend is observed at Murree station. As the trend of temperature is also observed and both the stations Islamabad and Murree shows increasing trend, but inflows at Khanpur shows the decreasing trend over the years.
