New Jersey Water Science Center
Great Falls of the Passaic River at Paterson, N.J.
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Toxics Hydrology Program - Unsaturated Zone Processes and Shallow Groundwater Quality
Project Title: NJ109 Toxics Hydrology Program - Unsaturated Zone Processes and Shallow Groundwater Quality
To develop quantitative understanding of the relation between unsaturated zone transport and shallow ground water quality. To document the relevance of unsaturated zone processes to major ground water contamination problems including natural attenuation.
Statement of Problem
The Unsaturated Zone is a critical, yet poorly-understood part of the hydrologic cycle. Although it controls the flux of water and chemicals between land surface and the water table, the data necessary to evaluate transport, storage, and reactions occurring within the unsaturated zone are not routinely collected. The unsaturated zone, although often considered a black box, is a fundamental part of watershed budgets for non-point source contaminants. Unsaturated zone geology controls the movement of chemicals from land application to aquifer. Storage, transformation, and recharge and the effect of the spatially variability of these processes on the flux of compounds needs to be better understood to evaluate the effect of land use on ground water quality
Strategy and Approach
Field studies expressly designed to quantify unsaturated zone processes have been conducted including studies of natural attenuation at gasoline spill sites, evaluation of the atmosphere as a non point source for MTBE, and the effect of unsaturated zone geology on recharge variability. Mathematical models are developed to interpret the data and supplemental laboratory studies can also be part of the approach. The project’s current focus (2007) is on variability of recharge, storage, and partitioning of ions in the unsaturated zone and the effect of these processes on the flux of nitrate and pesticides to ground water in agricultural watersheds.