Investigating the causality of changes in the landscape pattern of Lake Urmia basin, Iran using remote sensing and time series analysis

Abstract

Lake Urmia is the second largest hypersaline lake in the world in terms of surface area. In recent decades, the drop in water level of the lake has been one of the most important environmental issues in Iran. At present, the entire basin is threatened due to abrupt decline of the lake's water level and the consequent increase in salinity. Despite the numerous studies, there is still an ambiguity about the main cause of this environmental crisis. This paper is an attempt to detect the changes in the landscape structure of the main elements of the whole basin using remote sensing techniques and analyze the results against climate data with time series analysis for the purpose of achieving a more clarified illustration of processes and trends. Trend analysis of the different affecting factors indicates that the main cause of the drastic dry out of the lake is the huge expansion of irrigated agriculture in the basin between 1999 and 2014. The climatological parameters including precipitation and temperature cannot be the main reasons for reduced water level in the lake. The results show how the increase in irrigated agricultural area without considering the water resources limits can lead to a regional disaster. The approach used in this study can be a useful tool to monitor and assess the causality of environmental disaster.

Environmental degradation at Lake Urmia (Iran): exploring the causes and their impacts on rural livelihoods

“…The LU basin's semi-arid climate shows considerable seasonal variations in air temperature, generally between 0 and -20°C in winter and up to 40°C in summer (Mehrian et al 2016). Annual precipitation varies between 300 and 400 mm, 77% of which occurs between December and May, while the annual evaporation rate from the lake surface is approximately 1000 mm.…”

“…The causes of the enormous water loss of Lake Urmia are manifold and continue to be extensively studied and discussed in the scientific community (Hassanzadeh et al 2012;Mehrian et al 2016;Shadkam et al 2016;Talebi et al 2016;Khazaei et al 2019). Generally, the decline is blamed on a combination of climate change and human-induced drivers (Agha Kouchak et al 2014;Jalili et al 2016;Alizadeh-Choobari et al 2016;Ghale et al 2017;Arkian et al 2018;Chaudhari et al 2018).…”

“…The availability of irrigation water accumulated behind the dams has in turn led to increasing rates of water withdrawal and evaporation, and these water infrastructure developments have not only reduced direct water inflow into the lake, but they also allowed the overall size of the total cultivated area to triple (Mehrian et al 2016;Dalby and Moussavi 2017). Additionally, many of the previously exclusively rainfed agricultural lands have become irrigated farmland, growing from 3035 km 2 in 1984 to 5086 km 2 in 2014, an increase of 67.5% (Mehrian et al 2016).…”

Health effects of shrinking hyper-saline lakes: spatiotemporal modeling of the Lake Urmia drought on the local population, case study of the Shabestar County

“…Earlier studies also confirmed that drought leads to airborne salt-dust scatter 7 , 14 , 31 – 33 . When the saline flow sources around the lake are activated during monsoon season, they emit a wave of salt-dust into the air that can reach the neighboring cities 34 . The atmospheric aerosol is a complex and dynamic combination of solid and liquid particles affected by natural phenomena and human activities 35 .…”

Monitoring and Assessment of Water Level Fluctuations of the Lake Urmia and Its Environmental Consequences Using Multitemporal Landsat 7 ETM+ Images

“…Furthermore, the water level of Lake Urmia has decreased from 1270.64 to 1270.38 cm in 2011, showing a 0.26 cm decline in 1 year. Some researchers believe that the dam construction on the upstream rivers is the main contributing factor in declining of the Urmia Lake water level [53,54]. At the same time, the water authorities claim that climate change is the main reason [24,55].…”