Joining Forces VHB + The Johnson Company
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Sediment & Surface Water Characterization

Sediment & Surface Water Characterization

Sediment & Surface Water Characterization

Contaminated sediments in rivers, lakes, and harbors pose significant challenges for clean-up. Our skilled and experienced teams of professional engineers, hydrologists, aquatic biologists, ecologists and risk assessors use a multi-disciplinary and site-specific approach to create solutions that are cost effective. JCO teams rely on innovative field techniques and risk-based approaches to assess the sediment problem. Whether a site is a large Superfund site or is one of hundreds of smaller sediment sites containing heavy metals, polychlorinated biphenyls (PCBs), or polycyclic aromatic hydrocarbon (PAH) contaminants, we successfully develop effective remedies that meet the objectives consistent with the National Research Council in their risk management strategy for contaminated sediments.

For more than a decade, we have worked with clients to successfully develop solutions for surface water, wetlands, and sediment problems. Our services include:

  • sampling for chemical, physical and biological analysis

  • in-situ and laboratory testing of sediment geotechnical characteristics

  • surface water monitoring, and

  • evaluating groundwater/surface water interactions.

Our teams use an extensive inventory of sediment and water sampling equipment to conduct projects in wetlands and shallow, near-shore environments; fresh water rivers, streams and lakes; inter-tidal zones, and; harbors and bays.

Sediment Sample Collection

We meet a myriad of challenges collecting soft sediment samples using proprietary techniques for sediment coring that have been designed, developed, and used by our skilled team members. We have successfully collected hundreds of sediment samples from a wide variety of sediment types throughout the U.S.

Our specialized vibratory coring device for soft sediments can be mounted on any sampling vessel to collect cores using clear butyrate core liners that allow for stratigraphic observations without disturbing the core and without loss of volatile organic compounds. This equipment also enhances recovery and reduces consolidation and compaction in the core. It can be used with thin-walled or piston corers when laboratory geotechnical testing is required, since these methods provide the best recovery and least disturbance of the sediment core.

In-Situ Weak Sediment Strength Testing

We have developed a unique method of assessing very weak sediment strength through the use of high-sensitivity in-situ vane shear test equipment. These data can be collected rapidly in the field to provide inexpensive vertical and horizontal characterizations of sediment strength, and which correlate well with laboratory undrained, unconfined triaxial tests.

Biological Sampling and Testing

Our aquatic biologists and ecologists possess years of extensive experience in freshwater aquatic plant and benthic invertebrate surveys; fish and aquatic vertebrate collection, dissection and tissue sampling; and periphyton sampling. Our deployment of underwater video cameras linked to Global Positioning System (GPS) units allows detailed visual evaluation and precise mapping of benthic habitat and subaqueous conditions.

Surface Water/Groundwater Interaction Studies

Our national and international experience assessing the interaction of contaminated groundwater and surface water to evaluate surface water impacts contributes to our significant record of designing and implementing remedial solutions.

Surface Water Current and Flow Studies

We use current meters, salt dilution, and automated stage gauging to measure surface water flow.  To measure dilution and dispersion characteristics of direct discharge plumes into surface water, our specialized staff uses low detection-limit fluorometers during dye studies using procedures developed by the U.S. Geological Survey.

Automated Monitoring

We meet the challenges of continuous monitoring and data collection by custom designing remotely-operated data collection stations that use durable, versatile and programmable data loggers. This approach, often using solar-energy as a power source and direct cell phone communications, delivers stage and flow, water quality, weather, and treatment system data at a significantly lower cost than manual monitoring.

Proof of Expertise: Completed Projects and Successes

Natural Resources Damage Compensation Site

PCB Contaminated Sediment

Manufactured Gas Plant Superfund Site


JCo Sediment and Surface Water Field Program Experts