“Ground and surface water resources are in critical conditions and the drought in the region is unparalleled over the last half a century,” ISNA also quoted Mohammad Shahriari as saying.
Tehran has received a meager 0.4 millimeters of rainfall since Sept. 23, indicating a dramatic 97% decline compared with the same period of last year when the figure was 14.3 mm.
The official said water flow into five dams around the capital was 2.214 billion cubic meters in the water year of two years ago (Sept. 2019-20), which decreased by 889 million cubic meters in the last water year (Sept. 2020-21), warning that water scarcity looms in the province.
“Dams supplying water to Tehran, including Taleqan, Latyan, Mamlou, Karaj and Lar, now hold a total of 477 million cubic meters of water, which are 252 mcm less than the same period of last year when it was 729 mcm,” he added.
The five dams together can hold 2 billion cubic meters of water, but now they are less than 30% full.
Giving a breakdown, Shahriari noted that Amir Kabir Dam holds 128 mcm of water, down 40 mcm compared to last year. Taleqan and Mamlou now have 197 mcm and 123 mcm, down 30% and 40% respectively compared to last year.
Water behind Lar and Latyan is 43 mcm and 26 mcm, respectively. The two dams have registered a respective decline of 53 mcm and 28 mcm compared to a year ago.
Cumbersome Regulations
Tehran Regional Water Company is struggling to implement water infrastructure projects because of cumbersome regulations and the bloated bureaucracy, as well as the lack of cooperation from state bodies like the Department of Environment and municipality.
Giving an example, he said DOE does not allow TRWC to increase water supply from Lar Dam to the east of the capital as the dam is a habitat of red spot trout, “an issue that can and should be resolved if they [DOE] were to cooperate”.
Tehran’s population density is 973 per square kilometer, which is 20 times over and above the national average. With nearly 13.5 million people, the capital has a 16.5% share of the total population.
Tehran accounts for less than 1.1% of the country’s land area, but is home to 16.5% of the population and 45% of the industrial base.
Shahriari hoped that with better rainfall in the next two months, the water situation will improve. In the last water year that ended on Sept. 22, 2021, farmers and industries consumed 14% and 8% more water compared to a year ago.
Hydropower Production
Hydropower production in Tehran Province has also decreased by 40% to reach 250,000 megawatt hours over the last six months due to low rainfall, he said.
Shahriari noted that output from nine hydropower plants in the province peaked at 548,000 MW/hours in 2019, but this did not exceed 431,000 MW/hours in 2020 and the downtrend has continued in 2021.
“Electricity generation from plants is designed according to projected water conditions. The rise or fall in power output depends directly on water levels in dams,” he said.
“Due to low precipitation and unsatisfactory conditions of water reservoirs last year, output from these plants was below normal.”
Hydropower constitutes approximately 12,000 MW of the total installed power generation capacity of 84,000 MW and plays a key role during outages by quickly restoring supply and supporting other plants (mostly thermal).