Abbas Kashani

The phenomenon of groundwater depletion and land subsidence, particularly in the Marvdasht plain, represents a serious ecological and infrastructural problem resulting from unsustainable groundwater extraction. Excessive and uncontrolled use of groundwater for agricultural, industrial, and water supply purposes leads to the depletion of aquifers, which not only causes a drop in groundwater levels but also leads to physical changes in the structure of the soil.

1. Ecological and Economic Impacts

Groundwater is a crucial source of fresh water, and its over-exploitation can have long-term consequences for both ecosystems and human activities. In the case of the Marvdasht plain, the drop in groundwater levels leads to land subsidence, which threatens agricultural production, destroys infrastructure, reduces groundwater quality, and increases water salinization. This phenomenon impacts not only agricultural lands but also aquifers, which are the second-largest source of fresh water in the world, making the issue even more severe from an ecological standpoint.

2. The Link Between Subsidence and Unauthorized Drilling

Land subsidence in the Marvdasht plain is largely associated with unauthorized well drilling, which leads to improper groundwater extraction. This practice is often a result of a lack of adequate regulations and control by authorities, which leads to excessive water withdrawal from aquifers. In this context, regulating well drilling and implementing strict monitoring of groundwater extraction are crucial for preventing further damage.

3. Solutions and Strategies

Addressing this issue requires a multidisciplinary approach that integrates ecology, policy, and technology. First, stricter laws and regulations regarding well drilling must be enacted, along with more efficient monitoring of groundwater levels. Given the specificity and severity of the problem, it is important to implement long-term protective measures, such as:

• Introducing a sustainable groundwater extraction system, which would include precise control over groundwater use and stricter penalties for illegal activities.
• Utilizing alternative water sources, such as wastewater reuse or desalination, to reduce dependence on groundwater.
• Rehabilitating ecosystems through the restoration of water resources and the reconstruction of damaged land.

4. Subsidence Zoning

Although the creation of a land subsidence zoning map is vital for assessing the damage, it only provides a temporary framework for analysis. Continuous monitoring of both the soil and groundwater is necessary to identify changes in a timely manner and adjust protective measures. Given the severity of the problem, this map must be the foundation for a long-term strategy involving all relevant sectors (agriculture, water management, urban planning, and ecological agencies).

The phenomenon of land subsidence caused by the excessive use of groundwater in the Marvdasht plain highlights a serious issue that requires urgent and comprehensive action. In addition to technological solutions, effective resource management, regulation, and education are key to ensuring the long-term sustainability of groundwater resources, protecting land and infrastructure, and preserving the environment.

In addition to local subsidence and sinkholes, there is likely to be some regional-scale subsidence above much or most of the connected aquifer system. In terms of water resources, even a small amount of subsidence can irreversibly reduce the aquifer porosity, resulting in permanent decrease in available storage space for future groundwater recharge, and potentially even more significantly a permanent decrease in permeability of the aquifer; such that the aquifer system becomes permamently degraded for future role as a source of groundwater for human use.