‘Recent heavy rainfall not to compensate for water scarcity’

November 14, 2018 - 20:52

TEHRAN — Since the beginning of autumn, the country has been poured with rain, experiencing a 14 millimeters increase compared to the long-term average, nevertheless the water scarcity or the severe drop in groundwater resources are not compensated, director for drought and crisis management department at Iran’s Meteorological Organization has said.

Since the beginning of the current water year (September 23) up to November 12, the whole country has received some 35.5 millimeters of precipitation which demonstrates a 14 mm increase compared to its long term mean of 21.6 mm, ISNA quoted Sadeq Ziaeian as saying.

“It also exceeded the last year’s autumn rainfall rate of 11.2 millimeters by 24 millimeters,” he added.

The capital also has experienced 44.7 millimeters rainfall while the long-term averages are 29 millimeters which indicates a 15.7 millimeter increase in mean precipitation, Ziaeian explained.

He went on to say that during the aforesaid period last year, Tehran precipitation rate has been recorded 9.2 millimeters, so it increased by 35.5 mm this year, which was unprecedented.

Pointing out that since the beginning of autumn, most provinces of the country has faced an increase in rainfall compared to the long-term averages, he highlighted that the provinces of Ilam, Bushehr, Khuzestan and Kohgiluyeh and Boyer-Ahmad have experienced significant precipitation raise. 

On the other hand, the provinces of Ardebil, East Azarbaijan, Sistan and Baluchestan, Zanjan and Qazvin has met lower than the long-term rainfall averages, he lamented.

Referring to the impact of recent rainfall on water shortages, Ziaeian said that “initially we need to know how much the autumn rainfall normally contributes to rainfall of the entire current crop year (September 23, 2018-June 20, 2019).”

Autumn rainfall constitutes 25 percent of the total rainfall in a crop year, so that 3 percent of the country's total precipitation must be received in the Iranian calendar month of Mehr (September 23-October 22), 8 percent in the Iranian calendar month of Aban (October 23-November 22), and 14 percent in the Iranian calendar month of Azar (November 23-December 22).

Since two first months of the current crop year constitute 11 percent of the country’s total precipitation amount, so far, some 11 percent share of the two months has been provided and even the country got 6 percent above normal rainfall over the aforesaid period, he stated.

He further noted that it is anticipated that by the end of the autumn, most provinces of the country will meet normal or above normal rainfall rates.

While precipitation rate in the country has exceeded by 14 millimeters, it is not satisfactory enough to compensate for severe water shortages, since in the last 11 water years, the precipitation rates was below normal or, eventually, normal, as a result of which the groundwater resources and water stored behind the dams had fallen sharply, he regretted.

So, at least 11 years of normal precipitation average is needed to compensate for the current situation, he concluded.


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