Modeling the Impact of Surface Inflow in Declining the Urmia Lake Level by System Dynamics

Urmia Lake is the largest lake in Iran and the second largest saline lake in the world. This ecosystem is the habite for different species of birds and animals. Due to various aspects like economy, sociality, and ecology Urmia Lake has important role in the country. In fact, because of the high salinity of the lake, number of visiting birds is reduced significantly and thousands of them died. Unfortunately, this ecosystem faces many problems nowadays. Because of droughts, overuse of surface water resource, and dam construction, water level has been decreased and one quarter of the lake is changed to saline area within the last 10 years. The important aim of this research is to determine the effect of decrease in surface water on the lake's level. Therefore, in order to investigate the probability of lake's water level decrease in the result of each scenarios, a simulation model based on the system dynamic is developed for the Urmia Lake basin. Results show that between two factors, constructing 4 dams has 25%, and overuse of surface water resource has 65% effect in decreasing the lake's level in recent years respectively.