Investigating effects of climate change, urbanization, and sea level changes on groundwater resources in a coastal aquifer: an integrated assessment

Urbanization and climate change are causing numerous side effects on groundwater resources. In this study, an integrated modeling approach by linking soil and water application tool (SWAT), modular finite difference groundwater flow (MODFLOW), and three-dimensional variable-density groundwater flow coupled with multi-species solute and heat transport (SEAWAT) models were used to exhibit responses of groundwater systems, in terms of flow and salt concentrations to current and future climatic and anthropogenic changes. Future climate scenarios for periods of 2010–2040 were generated from the Canadian Global Coupled Model (CGCM) for scenarios A1B, B1, and A2 which was downscaled by the Long Ashton Research Station weather generator (LARS-WG) providing precipitation and temperature patterns for the period 2018–2040. The GCM’s outputs were applied to SWAT model to estimate recharge rate for the ten scenarios designed to assess the sensitivity of the aquifer to urbanization and climate change. The estimated recharge rate from SWAT was utilized as an input in numerical groundwater model to evaluate saltwater intrusion (SWI), changes in freshwater storage within the aquifer system, and changes in groundwater level. Based on the results of each scenario’s simulation, increase of pumping rate yield by future population growth will have more adverse effects on the unconfined aquifer. The derived information from this study can be used to improve future works by developing a better understanding of the managed and unmanaged response of freshwater storage and unconfined groundwater systems to climate change and anthropogenic activities.