Water Resources Supply and Demand Modeling using the Concept of Ecosystem Services in Sirvan Transboundary Basin

Water resources have always been a limiting factor in environmental planning. Understanding the status of this critical resource can have a significant impact on proper land use planning. This study aimed to estimate the water supply and demand as an ecosystem service and to identify areas with water stress in the Sirvan transboundary basin. This goal could be achieved using the concept of ecosystem services, which is new thinking in the earth sciences, and using geographical, climatic data, and satellite images. After relative corrections, Landsat satellite images for 2019 were prepared, and the LULC map was produced. Then precipitation, evapotranspiration, and root depth layers were created. The latest inputs, including the Evapotranspiration coefficients of the land cover and related tables, were prepared and modeled in the InVEST 3.8.9 software environment. The results showed that the amount of water yield in this watershed is 5,381 million m3/yr, where the sub-basin 5, 11, and 1 have the highest water yield with 1426, 906, and 621 million m3/yr. and sub-basin 2 with 100 million m3/yr have the lowest water yield. The sub-basin 5 with 110 million m3/yr has the highest consumption, and the sub-basin 2 with 7 Mm3/yr has the lowest consumption. Sub-basin 4, where the city of Sanandaj is located, has the highest water stress.