Assessing Future Water Availability Under a Changing Climate in Kabul Basin

Abstract

Climate change affects the patterns of precipitation and evapotranspiration and therefore can affect the future water availability and its spatial and temporal distribution. Climate change is also likely to intensify the global hydrological cycle, which can increase the risk of floods and droughts. This study focuses on Kabul basin which lies in the northeast quarter of Afghanistan. It accounts for thirty-five percent of the population’s water supply, and has the fastest population growth rate in the country. The main objective of this study is to assess the impacts of climate change on water resources. The climate projections are regionally available at finer resolution. Here in this study the future precipitation data were obtained from the selected models available from the Coordinated Regional Downscaling Experiment (CORDEX) program of the South Asian domain. The APHRODITE precipitation and temperature datasets were also used as observations in the lack of in situ measurements for the data-scarce Kabul basin. The SWAT hydrological model was then developed to understand hydrologic response of the Kabul basin and future projections of water availability under future climate scenarios. The median of the results from all used RCMs suggests an increasing trend in maximum and minimum temperature in the future, as compared to the baseline while the projections for precipitation mainly show a decreasing trend under both RCPs. Based on the results of hydrological modeling, the future runoff would likely increase due to the increased snowmelt in the study area. However lack of infrastructures might lead to further problems due to the possibility of more frequent and extreme floods and droughts.