Hydrology of mountainous areas in the upper Indus Basin, Northern Pakistan with the perspective of climate change

Abstract

Mountainous areas in the northern Pakistan are blessed by numerous rivers that have great potential in water resources and hydropower production. Many of these rivers are unexploited for their water resource potential. If the potential of these rivers are explored, hydropower production and water supplies in these areas may be improved. The Indus is the main river originating from mountainous area of the Himalayas of Baltistan, Pakistan in which most of the smaller streams drain. In this paper, the hydrology of the mountainous areas in northern Pakistan is studied to estimate flow pattern, long-term trend in river flows, characteristics of the watersheds, and variability in flow and water resource due to impact of climate change. Eight watersheds including Gilgit, Hunza, Shigar, Shyok, Astore, Jhelum, Swat, and Chitral, Pakistan have been studied from 1960 to 2005 to monitor hydrological changes in relation to variability in precipitation, temperature and mean monthly flows, trend of snow melt runoff, analysis of daily hydrographs, water yield and runoff relationship, and flow duration curves. Precipitation from ten meteorological stations in mountainous area of northern Pakistan showed variability in the winter and summer rains and did not indicate a uniform distribution of rains. Review of mean monthly temperature of ten stations suggested that the Upper Indus Basin can be categorized into three hydrological regimes, i.e., high-altitude catchments with large glacierized parts, middle-altitude catchments south of Karakoram, and foothill catchments. Analysis of daily runoff data (1960-2005) of eight watersheds indicated nearly a uniform pattern with much of the runoff in summer (June-August). Impact of climate change on long-term recorded annual runoff of eight watersheds showed fair water flows at the Hunza and Jhelum Rivers while rest of the rivers indicated increased trends in runoff volumes. The study of the water yield availability indicated a minimum trend in Shyok River at Yogo and a maximum trend in Swat River at Kalam. Long-term recorded data used to estimate flow duration curves have shown a uniform trend and are important for hydropower generation for Pakistan which is seriously facing power crisis in last 5 years.

Prevailing climatic trends and runoff response from Hindukush–Karakoram–Himalaya, upper Indus Basin

“…The DCP data were found of high quality and homogeneous. Only Naltar station has experienced inhomogeneity in T n , during September 2010, which was most probably caused by a heavy precipitation event that resulted in a mega-flood in Pakistan (Houze et al, 2011;Ahmad et al, 2012) followed by similar events in 2011 and 2012. Since station history files were not available, it was not sure that any statistically found inhomogeneity only in T n is real.…”

Assessment of Climate Change Impact on Reservoir Inflows Using Multi Climate-Models under RCPs—The Case of Mangla Dam in Pakistan

“…This approach has been used successfully [47][48][49][50]. Calibration of a model is a procedure in which the model parameters are adjusted in such a manner that the simulated flow captures the discrepancies of the observed flow [51].…”

Potential Impacts of Climate Change on Water Resources in the Kunhar River Basin, Pakistan

“…They used a Statistical Downscaling Model (SDSM), a combination of multiple linear regression and a stochastic weather generator, to downscale temperature and precipitation over the period of 2011-2099 under A2 and B2 scenarios of HadCM3, a global climate model. Different studies such as Akhtar et al [13], Ahmad et al [19], Shrestha et al [20], and Bocchiola et al [21] have assessed the impacts of climate change on the water resources of Pakistan [13,[19][20][21]. These studies were mostly conducted in the Upper Indus basin using hydrological models such as Snowmelt Runoff model (SRM), Hydrologiska Byråns Vattenbalansavdelning (HBV), Soil and Water Assessment Tool (SWAT), and the WEB-DHM-S model.…”