Name: Seyedeh Fardis Pourreza Ahmadi
Date: 03/25/2025
Time (EST/EDT): 11:00 am
Location: Carver Hall Conference Room, University of Maryland Eastern shore
Access: email mees@umd.edu

Committee Chair: Dr. Meng Xia
Committee Members: Dr. Thomas Miller Dr. Qian Zhang

Title: THE CONSIDERATION OF THE GROUNDWATER EFFECT ON THE CHESAPEAKE BAY THERMOHALINE SYSTEM

Abstract: Groundwater and surface water interact dynamically in coastal regions, playing a crucial role in watersheds including rivers, lakes, reservoirs, wetlands, and estuarine systems. Despite its significant role in salinity regulation, stratification, and freshwater balance, the groundwater influence is often overlooked in the surface water modeling system. Simultaneously, limited studies investigated the scenarios of fresh submarine groundwater discharge (SGD) into the surface water, particularly during extreme events which is further affected by the frequency of these events. This study employs a coupled Finite Volume Community Ocean Model (FVCOM) and ParFlow was conducted to analyze the hydrological and hydrodynamic interactions in the Chesapeake Bay, which is highly affected by recent frequent hurricanes. The results reveal a consistent spatio-temporal correlation between SGD and the river discharge patterns yet their influence on the estuarine thermohaline dynamics is inversely linked. Furthermore, we estimated that achieving the same density reduction as the scenario of river discharge removal would require intensifying the normal groundwater discharge approximately three times across the bay. Moreover, despite the river discharge dominance during the Hurricane, SGD played a secondary yet crucial role in controlling the deep thermohaline system. During the passage of the remnant of Hurricane Ida, prolonged precipitation led to a substantial rise in SGD into the Bay (~0.14 m³/s), which intensified the hurricane influences and even further disrupted stratification instead of enhancing it. These results have implications for the geochemical and biological processes of the Chesapeake Bay driven by SGD variations.