Restoring a Saline Lake to a Range of Water Levels With Noisy Data and Diverse Objectives
Abstract
Saline lakes are drying worldwide and there is widespread interest to restore them as the costs of lake desiccation can decimate adjoining economies and ecosystems. Here we synthesize 40 years of the available experimental, field, satellite, and model data for Lake Urmia in northwest Iran, which once was one of the world’s largest hypersaline lakes. We use the noisy data to define 10 restoration objectives for dust control, salinity, ionic composition, brine shrimp (Artemia spp.) survival, greater flamingo (Phoenicopterus roseus) abundance, island separation from each other and the mainland, connection between the north and south arms of the lake, recreational access, and agricultural benefits. We relate each objective to lake level and find: 1) The current government-set ecological lake restoration level of 1274.1 m above sea level is insufficient to reach a salinity target of 240 g/L nor is the salinity target sufficient to recover brine shrimp (Artemia spp.) and flamingos. A higher lake level may be needed. 2) Lake ecosystem services do not converge neatly to a single lake level as the ecological target of 1274.1 m implies. Instead, managers should identify the range of lake levels that maintain multiple ecosystem services. 3) Identifying a range of lake levels will offer managers of Lake Urmia and other international saline lakes flexibility to adopt and adapt their water allocation, agricultural development, and restoration strategies over time as they learn more about the lake system.
