Climate change impacts on water availability in the Ganges Basin

Abstract

The Ganges is one of the largest river basins in the world with an area of 10,87,500 km2. Water- related issues of the basin are due to both high and low flows and the problem will be more due to climate change. In this context, an attempted has been made in this paper to establish a basin scale hydrological model for the Ganges basin to predict the impact of climate change on water resources availability. A water balance model has been setup using physical based, semi- distributed hydrological model SWAT. Temperature and precipitation data from 9 GCMs and two SRES scenarios (A1B and A2) are used along with various input data (e.g., DEM, land use/cover, soil type, weather). Besides, assessment of statistical confidence of the results from different GCM is done utilizing the non-parametric Mann-Whitney U test. It is found that the average annual flow generated from the Ganges basin is 361,593 Mm3 . The results also indicate that the water availability will decrease during dry period and increase during monsoon. The average annual flow volume increases 22% by 2030, 26% by 2050 and 19% by 2080 for A1B scenario. A similar situation is observed for A2 also.