Assessment of future water availability under the changing climate: case study of Klang River Basin, Malaysia

This study aims to assess future water deficit and availability in Klang valley in the context of climate change. A surface water budget model for Klang river basin was developed using MIKE BASIN. The parameters for the Nedbor-Afrstromnings (NAM) model were determined and examined by trial-and-error approach and evaluated based on correlation coefficient (R), Nash-Sutcliffe efficiency (R-NS), and overall water balance error (WBer). The climate change scenario assessment used downscaled projected future rainfall data from 18 Global Circulation Models for the period 2046-2065. The assessment of water availability was carried out for Klang Gates Dam. The calibration and validation results for NAM model were satisfactory. The reservoir model verification result showed that the observed and simulated dam level were slightly dissimilar, which may be due to insufficient input data, particularly rainfall data as rainfall stations were very sparse upstream of the dam. The water deficit analysis for 2046-2065 showed that there will be water shortage in most of the months. The results of this assessment will help decision-makers evaluate the water availability and existing water infrastructure capacity in the vicinity of Klang river basin, particularly with respect to future raw and treated water yield.