Water levels for conservation of islands in Lake Urmia, Iran

This data contains the threshold water levels for the conservation of Lake Urmia's southern islands extracted using three methods.
Islands of Urmia Lake are nesting sites for various bird species (Eimanifar and Mohebbi, 2007). Four of these islands located at the south part of the lake have the highest priority for conservation within the ecological boundary of the lake. To determine the threshold water levels at which the islands start to be connected to each other and to the shorelines, we obtained the polygons of the islands' boundary as well as the bathymetry map of the lake (Karimi et al., 2016). We used three methods in parallel. First, we used the bathymetry map to determine the threshold water levels when islands connect to each other and to the lake shore. Also when the north and the south arms of the lake disconnect from each other. Second, we visually inspected daily MODIS satellite images which allow water bodies to be distinguished from land (false color composite of 7-2-1 bands; https://lance-modis.eosdis.nasa.gov). After finding the dates at which islands either merge together or connect to the mainland, corresponding water levels were extracted from the time series of the lake water level and checked with those from the bathymetric map. Finally, we used classified Landsat satellite images of Urmia Lake developed by Alizade Govarchin Ghale, (2014); Alizade Govarchin Ghale et al., (2017); Kabiri et al., (2012) and checked the areal extent of the delineated lake water body to estimate the corresponding lake water levels at which islands merge together, connect to shores, and the lake’s north and south arms disconnect. Then, we assessed the uncertainty of each method.