River water management using satellite radar altimetry data and WEAP model

This research aims to quantify the availability of water in the Indus River down Guddu barrage using advanced remote sensing technology. Pakistan's Indus Basin Irrigation System (IBIS) is the world's largest contiguous irrigation system and the backbone of the agriculture sector of Pakistan. The availability of water becomes challenging as we move downstream of the River. The most downstream province along Indus is Sindh, and Guddu is the most upstream barrage of the province from where major canals offtake from the river. The water supply-demand gap in the region is another challenge which needs to be correctly identified before proposing any remedial management options. For this purpose, we run Water Evaluation and Planning System (WEAP) model to determine this gap down Guddu Barrage. Seasonal River flows, and demand for agricultural, industrials and domestic consumers were used in the model. The major problem faced here was the unavailability of flow gauges at locations where supply information was needed. For that, we utilized satellite altimetry data for measuring water flows at various sites along Indus. We found a good match between gauge and altimetry data with root mean square error (RMSE) = 0.68 and Nash-Sutcliffe efficiency (NSE) = 0.61 for the validated model at upstream Guddu. Different scenarios were tested for determining the supply-demand gaps. The results show that the agriculture water requirement in the study area is not fulfilled especially for water-intensive summer crops such as rice when the River flows are also low. Management options, at the demand side to reduce these gaps, are also suggested in the paper.