Level Recorder

Water Level Recorder - In-stream

Tidal Fluctuations

Measured Tidal Fluctuations in Marsh - Water Level, Velocity, and Flow Data

 

acoustic doppler flowmeter

Preparing Culvert Mount for Acoustic Doppler Flow Recorder


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Success Story

Contaminated Sediments and Flow Hydrodynamics in a New Jersey Tidal Salt Marsh

LimnoTech conducted focused field investigations at the Universal Oil Products (UOP) Site in East Rutherford, New Jersey, to characterize bottom sediments and hydrodynamic flow patterns in a tidally influenced salt marsh environment. LimnoTech’s expertise in conducting sediment and hydrodynamic characterization field studies was used to provide critical data to refine the site conceptual model, support development of a tidal hydrodynamic model, and develop critically focused, cost-effective sampling strategies for an ensuing remedial investigation.

Problem
The potential for elevated concentrations of semivolatile organic compounds, polychlorinated biphenyls, chromium, and mercury was identified for surface waters and sediments at the UOP site. The study area consisted of tidal salt marsh with a series of man-made creeks. The creeks and wetland portions of the site drain the site during ebb tides; however, potential impacts to sediment and surface water may have migrated inland throughout the marsh and channel areas as a result of the tidal flow dynamics.

The site is highly complex, with strong tidal effects, complex wetlands hydrodynamics, multiple contaminants and many contaminant sources with varying source histories.  The primary challenge was to collect data that would provide sufficient insight into the site to allow planning and decision-making to go forward.

Approach
LimnoTech coupled conventional sampling and laboratory analysis methods with state-of-the-science instrumental deployments. Manual sediment coring and sampling techniques for an unstable water and marsh environment were employed to collect sediment samples for physical characterization and contaminant analysis. Sediment thickness probing was conducted to provide data for characterizing depositional characteristics in the system of waterways at the site. Water level (pressure transducers) and flow (acoustic doppler) recording instruments were installed at critical points throughout the waterway system to evaluate tidal flow dynamics throughout the site.

Result
LimnoTech’s work provided crucial data that supported the creation of an initial conceptual site model used to develop a sampling and analysis strategy that focused chemical characterization efforts to portions of the system most likely to act as repositories of contaminated sediment and to areas most critical to ongoing transport of contaminants. In addition, the generated data resolved data gaps critical to determining whether additional remediation actions were required and for determining offsite impacts to the UOP site.

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