Quantitative assessment of Urmia Lake water using spaceborne multisensor data and 3D modeling Mehrdad Jeihouni & Ara Toomanian & Seyed Kazem Alavipanah & Saeid Hamzeh Received: 9 July 2017 /Accepted: 12 October 2017 # Springer International Publishing AG 2017 Abstract Preserving aquatic ecosystems and water re- sources management is crucial in arid and semi-arid regions for anthropogenic reasons and climate change. In recent decades, the water level of the largest lake in Iran, Urmia Lake, has decreased sharply, which has become a major environmental concern in Iran and the region. The efforts to revive the lake concerns the amount of water required for restoration. This study monitored and assessed Urmia Lake status over a period of 30 years (1984 to 2014) using remotely sensed data. A novel method is proposed that generates a lakebed digital elevation model (LBDEM) for Urmia Lake based on time series images from Landsat satellites, water level field measurements, remote sensing techniques, GIS, and 3D modeling. The volume of water required to restore the Lake water level to that of previous years and the ecological water level was calculated based on LBDEM. The results indicate a marked change in the area and volume of the lake from its maximum water level in 1998 to its minimum level in 2014. During this period, 86% of the lake became a salt desert and the volume of the lake water in 2013 was just 0.83% of the 1998 volume. The volume of water required to restore Urmia Lake from benchmark status (in 2014) to ecolog- ical water level (1274.10 m) is 12.546 Bm 3 , excluding evaporation. The results and the proposed method can be used by national and international environmental organizations to monitor and assess the status of Urmia Lake and support them in decision-making. Keywords Urmia Lake . Remote sensing . Lakebed topography . 3D modeling . Long-term monitoring . GIS Introduction Human existence depends on global water resources. These resources comprise oceans, seas, lakes, surface water (rivers), and groundwater. Generally, seas, lakes, and wetlands collect the surface and groundwater flows of an area. In recent years, sharp changes in the quantity and quality of lakes water have motivated scientists to develop advanced methods to understand lakes ecosys- tems (Lytras 2007). Continuous monitoring of the char- acteristics of water resources in short- and long-term time scales are the key to sustainable management. Continuous monitoring increases permanent cognizance of the resource status and reveals their trends. Decision- makers can use this knowledge to make management decisions to preserve, restore, and make optimal use of the resources. Aquatic ecosystems are fragile and vul- nerable to damage by many natural and anthropogenic causes. The study of lakes and lake management has become critical to environmental and hydrological stud- ies (Moe et al. 2016; Templar et al. 2016; Al-Fahdawi et al. 2015; Ban et al. 2014; Hacısalihoğlu et al. 2016; Zhang et al. 2017a). Climate change has affected countries in both arid and semi-arid regions and their water resources. These Environ Monit Assess (2017) 189:572 https://doi.org/10.1007/s10661-017-6308-5 M. Jeihouni : A. Toomanian (*) : S. K. Alavipanah : S. Hamzeh Department of Remote Sensing and GIS, Faculty of Geography, University of Tehran, Azin Alley. 50, Vesal Str., Tehran, Iran e-mail: a.toomanian@ut.ac.ir