Projects & Programs
3-D Modeling of Suspended Sediment and PCB Fate and Transport in a New York Reservoir
Polychlorinated Biphenyl (PCB) contamination in the sediments of the Hudson River at the Sherman Island Hydroelectric Reservoir was documented in the mid-1990s. The raw water intake for the town of Queensbury, New York, is less than a mile from the site of the PCB contamination, and there was community concern that PCB could be re-introduced into the water supply. Niagara Mohawk retained PNNL staff, to provide engineering services to evaluate suitable remedial technologies (dredging/capping) for addressing the sediment contamination. The objective of this component of the study was to evaluate if the dredging operations, proposed as part of the remedial actions at the Queensbury site on the Hudson River, will cause extensive re-suspension and transport of PCBs and result in suspended PCBs reaching the water intake.
PNNL staff, developed a three-dimensional 3-D hydrodynamic and suspended sediment and PCBs transport model for the Queensbury site. The hydrodynamic model was calibrated using Acoustic Doppler Current Profiling current data. Sediment transport, resuspension and deposition were modeled using multiple particle sizes based on field data. Toxic contaminant (PCBs) configuration parameters initial concentrations, and partitioning coefficients were also estimated from field data. Reservoir inflows and outflows, temperature stratification due atmospheric forcing and inflow temperature and wind effect were considered in the model. Sediment and PCB fluxes through the sediment bed and water column interface were also considered. Different scenarios of sediment and PCB transport and their effects on the water quality at the drinking water treatment plant intake due to dredging operation are being simulated and investigated.
Project Highlights:
- Developed a 3-D hydrodynamic and sediment contaminants fate and transport model
- Calibrated the hydrodynamic model using observed water surface, velocity and temperature data and validated the sediment transport model for the existing condition
- Applied the model to simulated sediment contaminants transport under different dredging conditions
- Provided guidelines to prevent potential contaminants transport to the water treatment intake during dredging operations.