Mega structures being developed by the Caspian Sea littoral states (Iran, Russia, Azerbaijan, Kazakhstan and Turkmenistan) on the tributaries of the sea will substantially decrease water inflow into the lake in the long run, an environmentalist and a researcher at the Research Institute for Forests and Rangelands based in Tehran has warned.
“Close to 200 dams and other huge structures (floodgates and levees) are being built on rivers which feed the lake and upon completion would take a toll on the world’s largest lake,” Mohammad Darvish was quoted as saying by ILNA at the weekend.
The Volga River (Europe’s largest in terms of discharge that runs through Russia) is the largest tributary of the Caspian Sea and provides 85% of its water (260 billion cubic meters a year), he said.
The sea’s water level has seen a dangerous descending order over the past 18 years and registered an unprecedented 22-centimeter drop in 2016, he said.
“Low precipitation and evaporation are other causes of change in the level of the Caspian Sea.”
The water body was separated from the Black Sea in the Pliocene Epoch (around five million years ago) and has experienced numerous cycles of fluctuation ever since.
Caspian water level has decreased by 1.3 meters since 1996 and more decline is expected in the future. Darvish reiterated that transferring water from the Caspian Sea to the arid Semnan Province in north-central Iran would indeed make a bad situation worse.
Serious Danger
However, a more serious danger to the lake is the water quality that has deteriorated over the years.
“Water pollution level in the lake is 40 times greater than international norms,” Darvish added.
According to the expert, shipping in the sea is another growing problem that is contributing terribly to pollution.
Moreover, the release of over one billion cubic meters of industrial, chemical and household wastewater into the Caspian Sea per annum has polluted the water, and reduced oxygen levels, jeopardizing 400 plus aquatic species including sturgeons.
Oil exploration and transportation in the sea are other sources of pollution. According to published surveys, the sea contains close to 33 billion barrels of oil. Proven natural gas reserves in the Caspian region are estimated at 5 trillion cubic meters. Referring to water mismanagement and disorganized exploitation of groundwater resources, he said approximately 65% of Iran’s need for potable water comes from underground sources namely wells, qanat water systems and mineral springs that have been depleting at an alarming rate.
Illegal Wells
Over extraction from renewable and underground water resources is the main reason behind land subsidence in cities like Tehran in which more than 1,300 illegal wells were sealed in 2019.
“Sealing the wells helped save 35 million cubic meters of water,” Darvish said, implying that much more needs to be done to conserve water resources before the taps run dry.
Conditions are fast deteriorating in other dry regions.
“Not long ago wells were dug 40 meters and water gushed out in Kerman and Yazd for pistachio farms. Now farmers need to go down 350 meters, exacerbating the water deficits” that is emptying growing number of rural areas as farmers migrate to the big cites in search of work.
Water exploitation is banned in 420 plains because levels in these areas have plummeted by over 2 meters below minimum level.
In 2010 in Tehran and later in 2015 in Fars Province the earth went under by 36cm and 54cm, respectively.
The pattern of deficits in underground water resources has approached appalling levels due to the digging of unauthorized wells in the banned plains.
Referring to excessive withdrawals from authorized aquifers, Darvish said farmers are supposed to extract 36,000 cubic meters (per day), but the amount has long surpassed 50,000 cubic meters.
