Conley, Ethan William2025-05-072025-05-072025-05-06vt_gsexam:42907https://hdl.handle.net/10919/129381Addressing groundwater management and coastal hydrogeology in a changing climate requires an integrated approach using numerical modeling and geophysics. This dissertation explores groundwater sustainability, seismic risks, and submarine permafrost dynamics. The first two chapters examine the SWIFT Project, a managed aquifer recharge initiative for the Potomac Aquifer in coastal Virginia. Numerical models show that injections can induce pressure transients in basement rock, potentially triggering seismicity, but gradual injection increases help mitigate this risk. The Hampton Roads Seismic Network (HRSN) was established to monitor for induced seismicity, and a novel assessment workflow was developed to improve earthquake detection capabilities. Further research assessed freshwater availability on Pacific atolls, revealing significant impacts of sea level rise, precipitation changes, and human activities on water resources. Additionally, numerical simulations of submarine permafrost along a fiber optic cable off Oliktok Point, Alaska, predicted permafrost extent and temperature profiles, aiding in calibration of temperature sensing data and assessing future changes. These studies highlight the power of numerical modeling and geophysical methods in addressing groundwater sustainability, seismic risks, and coastal permafrost dynamics, offering critical insights for water resource resilience and environmental stability in coastal regions.ETDenIn CopyrightHydrogeologyNumerical ModelingInduced SeismicityVariable Density FlowGroundwater SustainabilityDissertation