Iran and Water Depletion

 Anthropogenic depletion of Iran’s aquifers | PNAS

Noori, R. et al. Anthropogenic depletion of Iran’s aquifers. Proc. Natl Acad. Sci. USA 118, e2024221118 (2021).

Decline in Iran’s groundwater recharge | Nature Communications

Noori, R., Maghrebi, M., Jessen, S. et al. Decline in Iran’s groundwater recharge. Nat Commun 14, 6674 (2023). https://doi.org/10.1038/s41467-023-42411-2

The article below is to a large extent excerpted from the work cited above.

In arid and semiarid areas like California and the Middle East, groundwater is the backbone of water and food security.  Groundwater provides about 60% of the total water supply in Iran, where agriculture is responsible for more than 90% of water withdrawal. Iran’s exports turn out to be food and oil.

from Noori, R. et al 

However, despite the importance of groundwater as one of the pillars of food and water security, extractions from aquifer systems exceed their natural recharge, -Iran is mining their limited water resources. Therefore, re-establishing the balance between the amount of groundwater withdrawal and recharge is essential to sustainably use groundwater resources if they are to avoid crisis.

Systematic groundwater extraction in Iran dates back to the Persian Empire at least two and a half millennia, when underground aqueducts known as “qanats” were excavated to transfer groundwater to the surface by gravity. The nature of how a quant works forces it to be sustainable. The Persian qanats that had enabled the development and agricultural production in Iran for thousands of years mostly dried up in the 20th century with “modern” agricultural practices the enabled population growth that demanded more water.

Deep well drilling and powered pumps made groundwater overexploitation possible, while increased surface water damming and diversion reduced groundwater recharge, together drawing down groundwater tables.  Aggressive water resources development to support the livelihood of over 80 million people and irrigate about 5.9 million hectares of agricultural land heightened the pressure on groundwater. Iran’s water scarcity in the 21st century has been exacerbated by frequent droughts and climatic changes.

The imbalance between groundwater withdrawal and recharge (i.e., groundwater depletion) was first reported in some aquifers in Iran in the 1970s. Currently, Iran records the volume of groundwater withdrawal from over one million extraction points, including wells, springs, and still functioning qanats, through its national groundwater monitoring network that covers all 30 national hydrological basins.

Groundwater overdraft has contributed to a host of problems, including the drying up of wetlands, desertification, sand and dust storms, deteriorating water quality, saltwater intrusion and population displacement. Land subsidence due to groundwater depletion is now a manmade hazard to vital infrastructure and residents in vulnerable plains where the land has been subsiding almost a foot a year

Nonrenewable groundwater extraction caused a cumulative decline in groundwater levels that averaging about 49 cm/y across the country. Groundwater consumption decreased from 60.7 km3 in 2002 to 55.2 km3 in 2015. This was not due to improved management of water resources, but due to surface water and fresh groundwater shortages. Not only is groundwater being used faster than the recharge rate, but the rate of groundwater recharge has also been falling.

from Noori, R., Maghrebi, M., Jessen, S. et al.  

 

In Professor  Roohollah Noori’s 2023 paper, he found that Iran’s countrywide groundwater recharge ratio (chart above), defined as the fraction of recharge to precipitation, declined from 21% in 2006 to14% in 2017. This is not far from what has been happening in other areas where groundwater has been mined, but rainfall in Iran is very low.  The researchers found that human interventions (not a changing climate) have dominantly impacted the decline in Iran’s groundwater recharge. Their research found that the average nationwide groundwater recharge was 39.6 mm/yr during the study period (that is less than 1.6 inches).  

Reduction in groundwater recharge combined with the nonrenewable groundwater discharge from the country’s aquifers further contributes to decline in groundwater storage and falling groundwater table. The current declining trend in groundwater recharge and the reducing trend in groundwater table reported by both Noori et al. and Ashraf et al. has resulted in a gradual decrease of Iran’s water and food security and makes the country’s landscapes prone to a wider spread of already occurring disasters, such as desertification, dust storms, landslides, land subsidence, sinkholes, droughts, floods, and fires.

Artificial recharge is a promising engineering solution to recover depleted groundwater resources globally. Iran is also making efforts to complete a national plan that aims to artificially recharge groundwater up to about 1km3. However, this amount is considerably less than the deficit between recharge of groundwater and use of groundwater Iran experiences each year. They could only slow the depletion of groundwater this way.

Engineering solutions alone cannot prevent the alarming depletion of groundwater resources for Iran, particularly when other factors such as countrywide land subsidence can hinder the effectiveness of recharge efforts. (You can not recharge land that has subsided.) The poor management of water resources, characterized by unsustainable land use changes, planning, inequitable allocation of water  rules, and institutional ineffectiveness in water management combined with the very poor economic conditions appear to have Iran on a slow path to extreme crisis without the added strain of outside actors.  The only way to address this over extraction of groundwater is through a cooperative and bottom-up approach that considers the interests of local stakeholders, particularly farmers, as the main consumers of groundwater resources. Without action Iran is moving towards water bankruptcy.