Climate Change Impact on River Flows in Chitral Watershed
Abstract
The impact of climate change has always been very important for water resources in the world. In countries like Pakistan where different weather conditions exist, the effects of climate change can be more crucial. Generally, the climate changes are considered in terms of global warming i.e. increase in the average temperature of earth’s near surface air. The global warming can have a strong impact on river flows in Pakistan. This may be due to the melting of snow and glaciers at a higher rate and changes in precipitation patterns. Glaciers in Pakistan cover about 13,680 km2 which is 13% of the mountainous regions of the Upper Indus Basin. Glacier and Snowmelt water from these glaciers contributes significantly to the river flows in Pakistan. Due to climate change, the changes in temperature and the amount of precipitation could have diversified effects on river flows of arid and semi-arid regions of Pakistan. This paper reviews the existing research studies on climate change impact on water resources of Pakistan. The past trend of river flows in Pakistan has been discussed with respect to the available data. Further, different projections about future climate changes in terms of glacier melting & changes in temperature and precipitation have also been taken into consideration in order to qualitatively assess the future trend of river flows in Pakistan. As a case study, the flows were generated for the Chitral watershed using UBC Watershed Model. Model was calibrated for the year 2002, which is an average flow year. Model results show good agreement between simulated and observed flows. UBC watershed model was applied to a climate change scenario of 1oC increase in temperature and 15% decrease in glaciated area. Results of the study reveal that the flows were decreased by about 4.2 %.References
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