Investigating Urmia Lake Partial Restoration and Ecological Water Level Using MOHID-2D Water Hydrodynamic Model

Lake Urmia as the third extremely-largest salty lake in the world (Garousi et al. 2013), owing to its unique natural and ecological importance, has been considering as a National Park (Abbaspour and Nazaridoust, 2007), Ramsar Site ( Ramsar Convention, )and UNESCO Biosphere Reserve ( UNESCO Bioephere Reserves, ). Artemia poses of the most important halophytic shrimpspecies that lives in the lake and no flora other than phytoplankton is found within the lake (Sima & Tajrishy, 2013). Four major islands situating in the south of the lake are either protected areas, or the destinations for diverse migratory birds including flamingos, pelicans, spoonbills, storks and gulls. More recently, the lake has been highly regarded due to its drying up caused by emerging drought, low rainfall, as well as decreased rivers flow feeding the lake. So that, the lake with different environmental, economic and tourism functions is now being died out and it experiences one of its most critical condition in the recent decades. The UNEP2 in its Global Environmental Alert Services (GEAS) bulletin dated February 2012, declared the status of the lake as alarming, which requires attention and immediate actions to avoid environmental catastrophe. Based on the conducted studies over the last decades (Abbaspour and Nazaridoust, 2007; Sima and Tajrishy, 2013), as long as the lake water level is greater than 1274.1 m.a.s.l, the lake will continue to its normal ecological function for maintaining biodiversity and Artemia production.Considering the Urmia Lake’s geographical and political location, as well as livelihood, identity and historical dependency of theregional people to it, the issue of the lake restoration and its prevention from drying up have become highlighted so far.According to several universal experiences (e.g. Micklin, 2007) with respect to partial restoration and rehabilitation of the lakescoping with drying up, Urmia Lake partial restoration is also discussed and inspected among Urmia Lake restoration committee experts; that being said, by accomplishing lake’s partial restoration, its ecological, environmental and habitat conditions are survived partially which aids to not confront the catastrophes which would take place in its complete death. By the same token, this study aims at addressing whether Urmia Lake partial restoration could save its ecological, environmental and biodiversity circumstances, or not. To this end, two scenarios were defined and compared including: S1) the continuation of the Urmia lake current status and S2) intersecting the lake from the islands location in the south and making this location behavior as a dike. A 2D hydrodynamic water modelling system named MOHID was used to investigate these scenarios effectiveness. The advantage of exploiting a 2D hydrodynamic model is that it can accurately compute the loss undergone by evaporation from lake water body by determining water body on the lake bathymetry which is the main cause of Urmia Lake water withdrawal