Water yield modeling in the watershed: a framework for sustainable water resources management

Water is a crucial strategic resource that greatly affects land use planning and ecosystem services. This study focuses on estimating the extractable water in the Qorveh-Dehgolan watershed in Iran using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model. The model utilizes various input parameters such as average annual precipitation, evapotranspiration, land use map, and water consumption. The water yield was modeled for two time periods, 2010 and 2022. To optimize water allocation, a linear programming model (LPM) was applied considering different scenarios for cropping patterns and water requirements of crops. The findings reveal that the water supply in the entire watershed was 336,921,424 m3 in 2010 and is projected to be 366,009,785 m3 in 2022, indicating a difference of 30 million m3. Meanwhile, the annual water requirement for agriculture in the watershed is approximately 300 million m3, leaving an excess supply of 45 million m3 (excluding drinking water and industry needs). Results of LPM indicated that net economic profit can increase up to 10.11% when groundwater consumption is reduced by 20% compared to current conditions. The results highlight the importance of optimizing cropping patterns based on water requirements for effective water management. By considering uncertainties and using a linear programming model, the optimization of cropping patterns can lead to more efficient water consumption and ensure sustainable livelihoods.