Evaluation of water management strategies to protect coastal wetlands as an ecosystem dependent on groundwater

Understanding the hydraulic connection between groundwater sources and coastal wetlands, as an ecosystem dependent on groundwater, plays a crucial role in the protection and management of coastal wetland ecosystems. This study focuses on the hydraulic management of the Anzali coastal wetland, situated in a shallow coastal aquifer with numerous rivers flowing into it. To investigate the intricate hydraulic interplay between surface water and groundwater, the MIKE SHE model was employed. The results revealed that the groundwater level surrounding the wetland is lower than the water level within it. Consequently, the study evaluated options for controlling groundwater extraction (scenarios 1 and 2) and river management (scenarios 3 and 4) in three different conditions: drought, extreme drought, and normal years. The study focused exclusively on how different scenarios affect the groundwater level of the wetland area, despite the known significant impact of changes in river flow on wetland water protection. The findings demonstrated that changes in groundwater extraction significantly affect the groundwater level, particularly in drought conditions. The results show that changes in groundwater extraction have a significant impact on the groundwater level, especially in drought conditions, such that in these conditions, the first and second scenarios result in an average decrease of 0.96 meters and an increase of 1.56 meters in the groundwater level in some areas close to the wetland. The results of the scenarios 3 and 4 caused minimal changes in the groundwater level, with the most significant impact observed in observation well located near the river.