Modeling the effects of irrigated agricultural development on the hydroclimate of the Lake Urmia Basin

Abstract

Lake Urmia is one of the world’s largest hyper-saline lakes, which has faced a severe drop in water level in the last three decades. To study the effects of irrigated agriculture development on the hydrology of the Lake Urmia basin, a regional climate model, RegCM, was used to simulate the hydroclimate of the basin under different land use and land cover (LULC) scenarios. The findings demonstrated that the growth of irrigated agriculture increases actual evapotranspiration, and affects other components of water and energy balances. Under the past scenario, the lake’s water right is fully provided. But, under the current scenario, only about 42.2% of the lake’s water right is supplied, and under the future scenario, even the agricultural sector will face a water deficit. Regarding the implementation of the Urmia Lake Restoration Program (ULRP) strategy of reducing water consumption by 40% in the agricultural sector, 59.8% and 15.3% of lake’s water right is provided under current and future scenarios, respectively and if other solutions (water transfer from Kani Sib dam and Silweh dam) are used, 85.3% and 40.8% of the lake’s water right is supplied under current and future scenarios, respectively. Considering the effect of climate change on the hydroclimatic conditions of the basin, it is necessary to study the combined effects of LULC change and climate change on the water balance of Lake Urmia.