Groundwater Depletion in an Arid Aquifer: Insights from Long-Term MODFLOW Modeling of the Kerman Plain

The significant impact of climate change, reduced precipitation, and drought in recent decades has led to a marked decline in both surface and groundwater levels. This crisis has particularly affected regions with arid and semi-arid climates, resulting in excessive abstraction from various aquifers. The Kerman Plain aquifer, which is located in an arid to semi-arid region, has also experienced a severe drop in groundwater levels over these years. Therefore, quantitative assessment of groundwater levels in this plain is of great importance for improving management and decision-making during serious water crises. In the present study, a 22-year simulation of groundwater levels in the plain was conducted using the GMS software and the MODFLOW numerical model. Future aquifer conditions up to the point of reaching the bedrock were predicted based on groundwater levels in the Bodaghabad well, located in the northern part of the aquifer within the Kerman urban area. According to the modeling results for the period 2002–2024, the greatest annual decline was observed in the western and eastern regions, averaging 1.23 meters, while the minimum decline 0.27 meters per year occurred in the central and southern parts of the aquifer. Furthermore, the findings showed that the diversion of Kerman’s urban wastewater for use by adjacent industries, and the consequent lack of aquifer recharge from the city’s natural wastewater drainage, have increased the groundwater level decline rate by 15.85% and shortened the time to reach bedrock in the Kerman urban area by 14 years.