عنوان مقاله [English]
Domestic, industrial and agricultural water supply has become a formidable challenge in light of population growth. Various water stakeholders, particularly in arid and semiarid basins, compete for profit that brings about severe conflicts in water allocation. Upstream stakeholders usually take their increasing share such that downstream water demands are becoming more difficult to meet. In this respect, environmental demands, such those of lakes and wetlands, are increasingly neglected.Urmia Lake in northwestern Iran, known as the second largest saline lake in the world, is a vivid example of negligence in providing environmental water rights. Urmia Lake is currently under the environmental threat due to prolonged droughts which causes reduction in rainfall, inflow, and water level in the lake. For a realistic water resources management in such situation, the estimation of inflow threshold for each drought severity state is the first and most important step . In this study, based on the analysis of lake’s historical inflow time series, environmental requirement subject to various drought severity conditions was estimated as thresholds for decision making in the future. Then analysis of existing condition (current inflow with regard to in operation dams and water withdrawals) was considered by system dynamic approach and water inflow to the lake was calculated under each scenario and compared by determined thresholds. Results of basin simulation revealed that if the water inflow to the lake remained the same as the current condition and water withdrawals were continued as previous, the lake will remain in moderate hydrological drought condition even with no dam construction or development in the basin. Therefore we need a trade-off between the current development in the basin due to water withdrawals and water resources projects and maintain required lake inflow for surviving it.