Schematic of grape farm on lake erie coast. Groundwater transports nutrients to the lake and outflow of groundwater contributes to erosion

Groundwater Discharges, Nutrient Transport and Bluff Erosion in Lake Erie

We are spinning up a new Pennsylvania Sea Grant funded project to look at the role of groundwater in coastal erosion and nutrient transport in Lake Erie. We will install groundwater wells at the Lake Erie Grape Research and Extension Center to monitor groundwater levels and nutrient concentrations in the surficial aquifer. We will use the observational data to construct a numerical model to simulate groundwater flow and transport in the study area. The observational data and numerical model results will be used to estimate groundwater and nutrient fluxes being exported to Lake Erie, evaluate whether groundwater is a driver of bluff erosion, and develop curricula to meet new Science, Technology & Engineering, Environmental Literacy and Sustainability (STEELS) standards at local middle and high schools.

Ocean Surge-Driven Salinization of Delaware Inland Bays

Coastal communities around the world face an increasing risk from surge-driven inundation because of rising sea levels and intensifying storm conditions. During storm surges, inland propagation of ocean water drives infiltration of saltwater into the fresh groundwater, jeopardizing coastal water resources. The magnitude, shape, and duration of these ocean surges vary both between storm events and spatially during a given storm, resulting from differences in bathymetry, coastline shape, and the path and characteristics of the storm. This project used a coupled surface water-groundwater model (Hydrogeosphere) to study how these temporal and spatial variabilities in ocean surge affect groundwater salinization and recovery in the Delaware (DE) Inland Bays.

Top: Schematic showing pumping and sea level rise driving salt water  further into a coastal aquifer. Bottom left: Numerical model domain of Dover delaware, showing marsh tidal streams and pumping wells. Bottom right: salt distribution in model

Effects of Sea-level Rise and Groundwater Pumping on Salinization in Coastal Aquifers

Water security has become a global concern as climate change progresses and rising populations increase stress on freshwater resources. Coastal communities face an additional level of risk of contamination from saltwater intrusion (SWI) driven by rising sea levels and groundwater pumping. In Dover, DE there is competition for groundwater from the surficial aquifer between the City of Dover and irrigating farmers. A field-based numerical model (SEAWAT), which includes included salinized marshland and tidal streams, along with irrigation and municipal pumping wells was applied to test various pumping reduction and redistribution approaches to determine the most effective SWI mitigation strategies.

Barrier Island Groundwater Dynamics

Nearly 1.5 million people inhabit barrier islands along the U.S. Atlantic and Gulf Coasts and coastal groundwater dynamics influence the availability of freshwater, ecosystem health, pollutant transport, and flooding in these densely populated communities. However, groundwater dynamics, including the aquifer head distribution and subsurface salinity structure, in coastal aquifers are affected by multiple environmental forcings, such as waves, tides, storm surges, and precipitation that act on a variety of spatial and temporal scales, making coastal groundwater dynamics complex and difficult to predict. In this project, we used 3-years of groundwater observations and community science data to:

  • Characterize ocean-aquifer-sound exchanges and the evolution of the upper saline plum during storms

  • Characterize the difference in the propagation of water table fluctuations driven by tides and ocean surges

  • Predict the timing and location of groundwater-driven flooding along the Outer Banks