While rainfall has surpassed 340 millimeters in the 12-month period, it barely reached 169 millimeters in 2017-18 water year.
"This year's precipitation [340 millimeters] has been 39% over and above the annual average registered over the past 50 years," IRNA reported.
Iran is divided into six primary river basins. The Caspian Sea in the north and Hamoun Wetlands in the east (mainly in Sistan and Baluchestan Province) have the highest and lowest rainfall since last September. The former registered a record of 554 millimeters, up 42% compared to the previous year. The latter was barely 120 millimeters, according to Financial Tribune.
The figure in other basins, namely the Persian Gulf and Sea of Oman in the south, Urmia Lake in northwest, Karakum and the Central Plateau in Markazi Province, amounted to 538 millimeters, 493 millimeters, 311 millimeters and 213 millimeters respectively in the 12-month period.
“Tehran dams hold approximately 993 million cubic meters of water or 342 mcm more than last year and almost 66 mcm more compared to the long-term average,” managing director of Tehran Regional Water Company Hassan Razavi told the news agency.
Since last September, Tehran has received 371 millimeters of rain, which shows a 78% increase compared to the corresponding period last year, and up 48% compared to the long-term average, Razavi said.
Heavy rainfall since last autumn, which peaked in March and April, increased the water in dams to levels unseen in almost half century.
Since September close to 2.3 billion cubic meters of water has entered Tehran dams, namely Taleqan, Latyan, Mamlou, Karaj and Lar, up 64% compared to the same time last year when 1.4 bcm of inflow was registered, Razavi noted.
Chronic Shortage
Despite the fact that rainfall in all basins experienced an upward trend, people and authorities have voiced concern about water scarcity as many regions across the countrystruggle with chronic water shortages that has taken the form of a severe crisis.
Iran has been battling drought for decades because of declining rainfall, rising temperatures, old and inefficient farming practices, excessive consumption in the metropolises and poor water management.
According to a recent report by the prominent National Geographic magazine, in recent years Yazd, Kerman, Fars and Sistan and Baluchestan provinces have been bogged down in persistent environmental disasters. A lingering drought has hastened the depletion of groundwater resources and disappearance of wetlands which were once a major source of water for irrigation.
Furthermore, recent studies in Columbia University show that the proportion of the rural population in Iran is dwindling as urban areas grow fast. Since the 1970s, the usage of groundwater in Iran has increased around fourfold and the average decrease in groundwater tables has been in the region of 50 centimeters per annum.
Despite measures taken to avert the disaster, desertification is still a serious ecological challenge in many regions in Iran. The country has different climatic and geographical zones (mountainous and desert areas), mostly arid and semi-arid, which are suffering from land degradation.
Excessive use of water resources, mainly for agriculture, has created negative water balances, changes in plant cover and accelerated desertification.