COI Funded Project: Developing the Concept of a Coastal Groundwater Observatory


Project Funded: 2004
Keywords: groundwater, nitrogen, eutrophication, coastal ocean, observatory

Proposed Research

With 75% of the world’s population expected to live within 35 miles of a coastline by 2020, it is vitally important that we understand how anthropogenic contamination is transformed in the environment as it is transported from land to the ocean.  A major source of coastal pollution arrives via groundwater, which can accumulate contaminants from wastewater, agriculture and atmospheric deposition.  Beneath beaches along the coastline, fresh groundwater mixes with salty groundwater (a zone called the “subterranean estuary”) and the resulting changes in salinity and oxygen content leads to the potential for significant chemical transformations.  The objectives of this project are to establish a pilot Coastal Groundwater Observatory, with the overall scientific goal of determining how tidal and seasonal changes in the subsurface flow and solute regime in a coastal setting control land-derived nutrient fluxes to estuaries.  Water level and salinity measurements in both high and low flow coastal groundwater areas will allow us to determine how groundwater velocities influence the shape of the subterranean estuary, while nutrient analyses will allow us to determine the extent to which salinity and groundwater velocities, and hence residence times, affect nutrient transformations.