Calibration and Economic Evaluation of the Water Yield Ecosystem Services in Basins by the Eastern Border of the Country

Water yield is a key indicator of the performance and valuable ecosystem service that directly affects the sustainable development of the economy, human well-being, and ecosystems of the basin. Using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, were simulated water changes in 10 basins, in the eastern border basin of South Khorasan province under the influence of land use/land cover changes. The model was calibrated using the long-term data of flow at Efin, Khonik Olia, Mansourabad, Gezik, and Ahangaran stations. Also, the economic value of produced water service was calculated in each of the different land uses/land covers. The results showed the highest volume of produced water in the Esfadan basin with 8,126,129 cubic meters, and the lowest in Namakzar khaf Basin equal 185,590 cubic meters. The amount of produced water in the whole studied area was 14836168 cubic meters. The highest amount of produced water was in the land use of dense and semi-dense range with more than 12 million and 430 thousand cubic meters, followed by the land use of sparse range with more than 1 million and 990 thousand cubic meters. The total economic value of produced water in the eastern border basins was equal to 16115806.5 million Rials. The spatial indication of the distribution of economic values of the ecosystem, which was carried out in this research through quantification, mapping and valuation of ecosystem services, can be used as important and reliable tools for natural capital management and policy making.