Characterizing flow pattern and salinity using the 3D MIKE 3 model: Urmia Lake case study

Abstract

In this study, MIKE 3 model was used to simulate flow pattern and salinity distribution in Urmia Lake. About two decades ago, a causeway was constructed in the lake. The causeway has a 1.25-km opening and divides the lake into northern and southern basins. To perform the simulation, different influential variables such as the discharge of inflow rivers, wind speed, variation in water density, bed roughness, air temperature, relative humidity, cloud coverage, and heat flux through water surface were taken into account. Using the available water level data, salinity, and current velocity, the numerical model was calibrated and validated. Results revealed that the northern part of the lake was saltier due to the negligible entrance of fresh water into the northern part as well as the construction of causeway which restricts water exchange between the northern and southern parts of the lake. Results also showed that density-driven currents are dominant and that the fresher surface water layer in the southern part moves north and circulates counterclockwise in the northern portion of the lake, increasing water salinity and density. This water then moves to deeper layers and circulates back to the southern part.