TEHRAN – Two Iranian scientists have warned that Lake Urmia’s revival trend may probably reverse over the coming years due to drought spells, though the lake has been filled mostly by the above-normal rainfall since the past crop year (September 23, 2019).

In an article entitled “analyzing the Lake Urmia restoration progress using ground-based and spaceborne observations” Peyman Saemian from the Institute of Geometry, Stuttgart University, Germany, and Omid Elmi from the Faculty of Geography, Bristol University, England suggested that due to the recent above normal rainfalls, the lake’s water level stabilized, while the revival process may not be sustainable, and with the onset of drought in the coming years, the trend will be reversed.

Lake Urmia, located in the northwest of Iran, was once the most extensive permanent hypersaline lake in the world. Unsustainable water management in response to increasing demand together with climatic extremes has given rise to the lake's depletion during the last two decades. The lake’s restoration program was established in 2013 and aims to restore the lake within a 10-year program.

The study aims to monitor these restoration endeavors using spaceborne and ground-based observations. The water storage change of the Lake Urmia catchment is quantified using the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On satellite observations, which gives us a holistic view of hydrological components.

The analysis shows a positive trend of 14.5 cm/yr, 204 km2/yr, and 0.42 km3/yr in the time series of lake’s water level, lake water area, and water volume from 2015 to 2019 which indicates a short-lived stabilization of Lake Urmia.

This has been achieved mainly due to an increase of 0.35 km3/yr in inflow from rivers to the lake, predominantly driven by anomalous precipitation events in 2016 and early 2019. However, the long-term trend from 2003 to 2019 still shows negative values of 22 cm/yr, 200 km2/yr, and 0.72 km3/yr for the water level, the surface area, and the water volume of the lake, respectively.

The stabilization seems to be fragile, however, since most of the increase in the water volume of the lake has spread over the large shallow southern region with high evaporation potential during hot seasons. Furthermore, due to the high correlation between the lake’s water level and precipitation, the recovery observed in 2016 and the first half of 2019 might not continue in case of a long drought period.

Achieving sustainable rehabilitation requires countless efforts, such as preventing the lake's water flow from entering the agricultural land. The results of this study showed that Lake Urmia’s condition stabilized with a positive trend due to heavy rainfall and there is a fear that this trend will be reversed by drought in the coming years.

Farhad Sarkhosh, head of the Lake Urmia Restoration Program’s office in West Azarbaijan province said that the lake’s level has reached 1,271.87 meters, which is 37 centimeters higher than the last year’s level.

The lake's water volume was estimated at more than 4.620 billion cubic meters, which indicates an increase of 1.010 billion cubic meters compared to the last year and 1.7 meters since 2014.

The above normal levels of rain came to help conservation measures to preserve the Lake Urmia, however, it still needs 9.5 billion cubic meters of water to reach its ecological level of 1274.10.

FB/MG