Land subsidence caused by the substantial decline in groundwater resources is expanding in Isfahan Province and has reached a critical juncture in some parts of the region, a lawmaker from the province said.
“Close to 2.5 million residents in the region are being unsettled by the gradual or sudden sinking of the ground,” Mohammad Taqi Naqdali was also quoted as saying by ILNA.
Rapidly declining water resources have impelled water officials in the arid province to increase the number of plains from which water withdrawal is banned to 30, he added, noting that there are totally 35 plains in the region.
Naqdali said plains in Borkhar and Mahyar counties, which extend over 4,000 square kilometers, are in imminent danger, as all aquifers in the areas have already been emptied.
Based on estimates by organizations like the International Association of Hydrological Sciences, if a piece of land sinks 4 millimeters a year, it is in critical conditions and the residents of the region are in danger.
The land is sinking by about 40 centimeters in Borkhar and Mahyar plains annually, which is 100 times more than the global standards.
"The problem has evolved over a long time and cannot be addressed overnight, but we hope that short-term measures will help improve present conditions and prevent the expansion of land subsidence," he said.
The official stressed that as 90% of the water are used in crop irrigation across the province, farmers should be taught to adopt methods compatible with the region's climate.
Disorganized urbanization, old and obsolete farming practices and the presence of water-intensive industries such as Mobarakeh Steel Company are adding pressure on Isfahan’s rapidly dwindling water reserves.
Groundwater resources in the parched region are shrinking by a massive 3.6 billion cubic meters per annum. Of the total annual extraction, 3.3 bcm are drawn from 41,000 authorized wells and the rest from 21,000 illegal wells.
Unauthorized Wells
Over 7,000 unauthorized wells have been sealed since 2005, which helped save 215 million cubic meters of water a year in the dry central region. The drop in groundwater levels is estimated to average 1 to 1.5 meters a year.
Excessive groundwater extraction has resulted in slow but steady land subsidence in the region. The annual subsidence rate in the different plains of Isfahan ranges between 20 cm and 40 cm.
In Iran, the population has more than doubled in the past 50 years, while groundwater pumping remains unregulated. The country’s cities are now among the fastest-sinking urban centers in the world, descending by up to 25 cm each year.
Many provinces, including Hamedan, Markazi, Tehran, Qazvin, Isfahan, Fars, Kerman, Sistan-Baluchestan, Hormozgan as well as South and North Khorasan and Khorasan Razavi, are severely grappling with the phenomenon.
Reportedly, Fars Province has the worst condition of all, since almost all wetlands and lakes have dried up, causing an annual 54 cm of land subsidence, based on figures released in 2016 by the Geological Survey and Mineral Explorations of Iran.
The most alarming situations have been witnessed in the 36-cm subsidence in Moeinabad and the 25-cm sinking of Varamin in southern Tehran. Furthermore, the land has sunk by 20 cm in Tus Plain in Khorasan Razavi Province.
UNESCO Research
Subsidence could affect 19% of the world’s population by 2040, according to new research funded by UNESCO.
If no action is taken, human activity, combined with drought and rising sea levels exacerbated by global heating, could put many of the world’s coastal cities at risk of severe flooding.
Jakarta has sunk more than 2.5 meters in the past 10 years, leading the Indonesian government to make plans to relocate the country’s capital to the island of Borneo.
In Europe, subsidence is responsible for pulling the Netherlands 25% below sea level. Flat coastal regions, as well as urban and agricultural centers in dry climates, are most at risk.
According to Hashem Amini, the head of the provincial water company, Isfahan Province has been suffering from drought for years. It is facing more serious problems this year due to the decline in last year’s precipitation that has resulted in a further reduction of surface water and groundwater.
“The severe decline in rainfall in the central region last year has caused renewed concerns among the residents and irreparable damage has been inflicted on the farming sector,” he said.
A recent report by the Iran Meteorological Organization said 80% of the region are affected by drought and the situation will get worse before it gets better.
In the not-too-distant past, the Zayandehroud river had regular and significant water flow, but is almost dry for more than eight months to the detriment of farmers largely dependent on the river for their livelihood.
Once the pride of the region, Zayandehroud originates in the mountains of Chaharmahal-Bakhtiari Province and flows eastward toward Isfahan before ending up in the famous Gavkhouni Wetland.
According to Amini, the need to treat and reuse wastewater is crucial to cope with the worsening crisis.
“Almost 172 million cubic meters of wastewater are recycled in the province a year,” he said, adding that of this volume, 60% or 100 mcm are used for farming and the rest by industries, green spaces, watersheds and anti-desertification programs.
After Yazd, Isfahan is the second biggest industrial hub in the country and 70% of Iran’s steel are manufactured in the province, which explains why tapping into unconventional water resources has become a pressing need.
