ASSESSMENT OF TEMPORAL FLOW VARIABILITY OF THE KABUL RIVER

Abstract

Water resources estimation under changing flow regimes is required for planning and smooth distribution of water to provinces. Since the hydrological parameters are changing significantly due to climate change, the changes in the pattern of flow regimes are definite. The objective of present study was to assess the spatial and temporal hydro variability of Indus basin. The data of Kabul river at Nowshera before its confluence with Indus river were collected from Surface water Hydrology Project (SWHP), WAPDA. The seasons were divided as three and six month keeping in view the hydrological cycle. Trends and variation were investigated by applying the Mann-Kendall test and Sen’s method. The presence of trends tested at different significant level, 99.9%, 95% and 90%. The overall analysis indicates that there is more flow variation on seasonal basis as compared to the annual basis. The Kabul river showed decreasing trend in the maximum mean annual discharge, whereas the minimum mean annual discharge showed increasing trend. It was concluded that Kabul river showed decreasing trend in annual mean and maximum discharge, whereas annual minimum discharge showed increasing trend. It was also noticed that Kabul river mean minimum discharge time series decreased during 1961-1985, whereas it increased during 1986-2010. It was also found that annual mean and maximum discharge decreasing rate was greater during 1986-2010. It was further concluded that each decade experienced one or two years of both dry and wet periods and that 2000-2004 was the driest period in the history of Kabul River.