By Faranak Bakhtiari

Saving karst aquifers vital to survive drought

August 9, 2021 - 21:39

TEHRAN – While the country is dealing with severe drought due to improper withdrawal of groundwater and low rainfall, karst water resources can supply the whole water needed by the country, only if managed.

Mohammad Reza Espahbod, an expert in groundwater resources, said that Iran is the fifth country in the world in terms of karst water resources.

Well known and described as a landscape, karst is a geological formation established in carbonate, limestone, and dolomite rocks. It is first and foremost an aquifer, a formation in which groundwater accumulates, circulates, and emerges at often important sources. It is often a remarkable and very special groundwater reservoir.

On a global scale, these karst formations cover 12 to 15 percent of the continental surface. It is estimated that about,25 percent of the world’s population is supplied with domestic water from groundwater extracted from the karst.

Many countries supply 30 to 40 percent of their drinking water from karst water, which can reduce the drop in water levels in aquifers and access to renewable water with appropriate quality.

Currently, the country, especially in the Zagros region, has abundant karst water resources.

In karst areas, water can be withdrawn by digging wells of at least 250 meters to a maximum of 500 meters. In order to achieve deep water, a well with a depth of more than one thousand meters must be drilled, Espahbod explained.

On a global scale, karst formations cover 12 to 15 percent of the continental surface.

At present, 5,000 liters, or 5 cubic meters of water per second, is extracted from karst sources in the world, the highest of which is in Yugoslavia, he added.

Vital resources that migrate

Alireza Shahidi, head of the Geological Survey and Mineral Explorations Organization said that the task of identifying karst waters is our responsibility, and based on this, we published the National Atlas of karst water areas.

Due to the climate change and drought that has been happening in recent years, karst water can be replaced as unconventional water that has a very high quality, he highlighted.
Referring to the studies conducted in the field of karst water in “Kopet Dag” region, Shahidi stated that “If these studies were successful, we could supply a large part of Mashhad's water, but due to the lack of proper attention, karst waters, especially in border areas, flow to neighboring countries.”

According to Shahidi, Turkmenistan is located at the top of the Kopet Dag region, and karst water in Iran enters Turkmenistan.

Saravan region in Sistan-Baluchestan province is a water-rich region, and despite the urgent need for water in this region, karst water is flowing into Pakistan, he lamented.

He went on to note that karst water resources in some cities of the country are emerging as springs in the ground, and the amount of water flow in these springs depends on the amount of rainfall.

Unlike groundwater, karst water resources can be regenerated, but the water that we extract from the underground reservoirs results in their shrinking day by day, therefore, many aquifers are in danger of depletion and the phenomenon of subsidence, he regretted.

Due to the fact that karstic waters are mostly in calcareous rocks and mountains if the water is harvested improperly, it will eventually dry out, but when it rains, water will enter the cavities in the mountains through the pores and these water sources will be regenerated, he said, emphasizing that underground aquifers cannot be regenerated.

Water resources shrinking

Renewable water resources have decreased by 30 percent over the last four decades, while Iran’s population has increased by about 2.5 times, Qasem Taqizadeh, deputy minister of energy, said in June.

The current water year (started on September 23, 2020) has received the lowest rain in the past 52 years, so climate change and Iran’s arid region should become a common belief at all levels, he lamented.

A recent report by Nature Scientific Journal on Iran’s water crisis indicates that from 2002 to 2015, over 74 billion cubic meters have been extracted from aquifers, which is unprecedented and its revival takes thousands of years along with urgent action.

Three Iranian scientists studied 30 basins in the country and realized that the rate of aquifer depletion over a 14-year period has been about 74 billion cubic meters, which is recently published in Nature Scientific Journal.

Also, over-harvesting in 77 percent of Iran has led to more land subsidence and soil salinity. Research and statistics show that the average overdraft from the country's aquifers was about 5.2 billion cubic meters per year.

Mohammad Darvish, head of the environment group in the UNESCO Chair on Social Health, has said that the situation of groundwater resources is worrisome.

More drought, water crisis

In March, Ahad Vazifeh, head of the national center for drought and crisis management, forecasted that the country will not receive much rain until the end of summer. A month later, he announced that an unprecedented drought had occurred in some parts of the country.

This is while in the following weeks, statistics showed that precipitation has declined by 60 percent in Iran over the first two months of the current [Iranian calendar] year (March 21-May 21) compared to the same period last year.

And, it dropped by 41 percent compared to the long-term average.

Drought impacts on human societies

The drought consequences will be very severe, and as long as we do not manage water consumption, we will attack groundwater resources. All the lakes, rivers, and wetlands of the country have environmental water rights, but in drought conditions, it is always natural ecosystems that are neglected and their water rights are not paid.

In drought conditions, the water right of rivers and wetlands must be granted, but not only does this not happen, but the water goes to agricultural lands where water-intensive crops such as onions and watermelons are grown. Therefore, water resources are wasted, because the Ministry of Agriculture has not succeeded in implementing the cultivation pattern.

Iran is a country where rainfall is one-third of the world average and has gone through many periods of drought throughout history, some of which have led to famine.

However, employment in the country is water-based and based on agriculture. However, due to the dry climate of the country, we should have used the tourism and handicraft capacities of local communities, but unfortunately, we have put all our energy, capital, and focus on agriculture.

During the severe drought of this year, the possibility of migration from rural to urban areas and from southern to northern provinces will definitely increase.

FB/MG

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