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The discharge of nitrate-contaminated groundwater from developed shoreline to marsh-fringed estuary

Water Resources Research

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Abstract

As residential development, onsite wastewater disposal and groundwater contamination increase in the coastal zone, assessment of nutrient removal by soil and sedimentary processes becomes increasingly important. Nitrogen removal efficiency depends largely upon the specific flow paths taken by groundwater as it discharges into nitrogen-limited estuarine waters. Shoreline salinity surveys, hydraulic studies and thermal infrared imagery indicated that groundwater discharge into the Nauset Marsh estuary (Eastham, MA) occurred in high-velocity seeps immediately seaward of the upland-fringing salt marsh. Discharge was highly variable spatially and occurred through permeable, sandy sediments during low tide. Seepage chamber monitoring showed that dissolved inorganic nitrogen (principally nitrate) traversed nearly conservatively from the aquifer through shallow estuarine sediments to coastal waters at flux rates of 13 mmoles m2 h1. A significant relationship found between porewater NO3N concentrations and NO3N flux rates may provide a rapid method of estimating nitrogen loading from groundwater to the water column.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The discharge of nitrate-contaminated groundwater from developed shoreline to marsh-fringed estuary
Series title:
Water Resources Research
Volume
34
Issue:
11
Year Published:
1998
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
3095-3104
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Water Resources Research
First page:
3095
Last page:
3104
Number of Pages:
10