Integrated Hydrological Modeling for Assessment of Water Demand and Supply under Socio-Economic and IPCC Climate Change Scenarios using WEAP in Lower Indus Basin

Abstract

Pakistan is one of the most vulnerable countries to water scarcity due to deterioration in socio-economic factors and lack of climate change adoption policies. Different hydrological modeling studies have been conducted in the Indus River Basin in the context of climate change scenarios. However, none of these studies addressed the issue of sustainable water management in the situation of socio-economic scenarios in the lower Indus Basin. This study focused on Scio-economic and IPCC climate change scenarios using the Water Evaluation and Planning (WEAP) model for sustainable water resources management of the lower Indus basin. Different socio-economic (population growth rate and increased agriculture activities) along with IPCC climate change (RCP4.5, and RCP 8.5) scenarios for the period 2015-2050 were used in the WEAP model for future projection of water availability and demand analysis. Indus River discharge data (1995-2014) was used to calibrate and validate the WEAP model. For Calibration (1995-2004) the Nash Sutcliffe efficiency and coefficient of determination statistics were 0.85, and 0.86. While for validation (2005-2014) the Nash Sutcliffe efficiency (NSE) and coefficient of determination statistics were 0.89, 0.87. The results showed that the combined adverse impact of climate change and socio-economic factors would result in less surface water availability and the total water demand will drastically increase to 20 BCM by 2050. The agricultural water management practices proposed by PARC (Pakistan Agricultural Research Council) will help to reduce the agricultural water demand by 50%. The comparative analysis of different scenarios revealed that the management strategies would help to reduce the unmet water demands in the future.