Future water demand modeling using water evaluation and planning: a case study of the Indus Basin in Pakistan

The Indus River Basin is the fourth-largest irrigation system in the world, contributing up to 25% of Pakistan’s gross domestic product and 90% of its food production. Various kinds of water users (i.e., rural, urban, subsistence, and commercial irrigated agriculture) exist in the catchment. The rising local population—in conjunction with climate change and the need to meet minimum flow requirements—will significantly exacerbate the complexity of future water resources management in an already water-stressed sub-catchment. The water evaluation and planning system (WEAP) model is widely used to analyze the complex water resources systems and to examine supply and demand management strategies. In this study, a scenario analysis is conducted using WEAP to assess the impacts of possible future water demands on Indus water resources. For each scenario, the water resource is compared to the baseline year of 2015, then analyzed according to two growth rate scenarios. These simulations may help in understanding the potential water management problems of the future. It is estimated that by 2040 if population continue at the census 2017 growth rates, the water demand of Punjab and Sindh provinces will increase to 192.7 billion cubic meters, which is more than the current entitlements and availability.