A water pipeline from Mamlou Treatment Plant in Pakdasht County (35 km southeast of Tehran) to Pishva County (45 km southeast of Tehran) was launched on Monday, managing director of Tehran Province Water and Wastewater Company said.
“The aim is to improve the quality of potable water in the southern regions of the overcrowded capital and control land subsidence in the Varamin Plain,” Mohammadreza Bakhtiari was quoted as saying by IRNA.
The 10 kilometer pipeline transfers 35,000 cubic meters of water to Pishva per day. It led to the decommissioning of at least 60 wells in the area where underground tables are plummeting due to excessive (80 million cubic meters per year) water extraction, he said.
Referring to the water quality, he added before Tehran's seventh water treatment plant (Mamlou Treatment Plant) was completed in January, water hardness in Varamin was 1,900 milligrams per liter.
“Hardness of the water that is now being supplied to the county is less than 800 mg/l and does not need to be desalinated before drinking.”
Water hardness is the amount of dissolved calcium and magnesium in the water. Hard water is high in dissolved minerals, largely calcium and magnesium. When using hard water, more soap or detergent is needed for cleaning, be it hands, hair or laundry.
Over 1.5 billion cubic meters of water is extracted from the ground in the capital every year
Built over 11 hectares, Mamlou Treatment Plant (from which the water is channeled to Pishva) has a capacity to treat 160 mcm of water per year and has improved the quality of tap water for at least 2 million people in the downtown districts, namely Shoush, Khavaran, Baqerabad, Khavarshahr, Varamin, Pakdasht, Qiamdasht, Naziabad, Afsariyeh and Yaftabad.
Five dams, namely Amirkabir and Taleqan (in the west) plus Latian, Lar and Mamlou (in the east) supply Tehran with potable water.
An 80-km pipeline connects Mamlou Treatment Plant to Mamlou dam (built on Jajroud River). The first phase of the project came on stream in 2015.
Almost 30% of Tehran's water is supplied from rapidly depleting underground resources and the new plant is helping gradually cut demand to 20%.
Sinking Plains
The earth sinks in some plains in Tehran Province by about 0.5 millimeter every day, and conditions are grave in Shahriar and Varamin counties in southwest and south Tehran, Bakhtiari said.
“An annual 310 mm of land subsidence is reported in Tehran Province. Over 1.5 billion cubic meters of water is extracted from the ground in the capital every year,” he warned.
Land subsidence is defined by scientific references as a gradual settling or sudden sinking of the earth's surface owing to subsurface movement of earth materials.
Principal causes are aquifer-system compaction as well as earthquakes. Nevertheless, the main reason of land subsidence in Iran is unreasonably high groundwater extraction that has caused serious concern among conservationists, environmentalists, economic experts and urban managers.
The disturbing trend has gone way beyond the global norm of annual 4 millimeters land settling.
“More than 200mm of land subsidence per year is considered critical,” Bakhtiari said.
Although reversing land subsidence is practically impossible, slowing its progress is doable provided the government and public mobilize for the task.
Whopping Deficit
Iran’s annual water consumption is 100 billion cubic meters, while it only has 90 bcm of renewable sources. How the ballooning deficit can be reduced is for the policymakers and water managers to answer.
Tehranis consumed close to 1.1 bcm of water in the past 10 months (September 2019-June 2020).
Tehran consumes almost 35% of the entire water produced in the country and accounts for 18% of the total 82 million population.
Bakhtiari said production of each cubic meter of drinking water costs the government 25,000 rials (12 cents) but it is sold for 6,000 rials 3 cents).
This wide gap in the form of costly subsidies has to come to an end sooner rather than later, conservationists and agro experts insist.
