The chemical dissolution of carbonate rocks and the over-pumping of the groundwater and reservoirs in Varamin Plain could eventually cause the collapse of the entire surface layer of Tehran province, according to Mehrdad Katal Mohseni, the deputy director of the Tehran Municipality Department of Environment.
In a meeting with farmers and factory owners in Varamin County, Mr. Mohseni warned: “We may see the gradual or sudden appearance of massive sinkholes in the region.”
He added: “One of the leading causes of land subsidence is the over-pumping of reservoirs and groundwater. The standard practice is to pump 40 percent of the reservoir. However, the volume of water pumped in Varamin is four times that amount. The surface area of Varamin County sinks 36 centimeters a year.”
Mr. Mohseni warned that the over-pumping of water by farmers and cattle owners had severely depleted the Band Alikhan Wetland in southern Tehran. Traditional farming is one of the leading causes of water shortage in many plains that had previously been fertile. According to Mohseni, since 2015 the government has placed a ban on pumping water in 309 lowlands out of a total of 609 that have groundwater and reservoirs. Another 300 plains are either arid or hold salt water.
The Rafsanjan, Zarand, Mashhad, and Ghazvin plains sink by 30, 25, 25 and 24 centimeters every year, respectively.
Many seismologists have warned about the rapid sinking of the surface layer in southern and western parts of Tehran. According to the Tehran Province Water and Wastewater Company, the reservoir and surface layer of Varamin County drops by 1.3 cubic meters and 16 centimeters a year, respectively. Close to 370 million cubic meters of water is pumped from the Varamin reservoir every year, of which 340 million cubic meters is from licensed wells and the rest from unauthorized sources.
Translated from Persian by Fardine Hamidi