The Woods Hole Group simulated the hydrodynamics and resulting pollutant transport due to the effects of a historical hurricane in the New Bedford Harbor Region, including the Acushnet River estuary. Of particular interest was the immense flooding of the upland due to the accompanying storm surge, and the release and transport of chemicals from a confidential entity. A combination of historical data retrieval and numerical modeling was used to accomplish these tasks.

The historical data was needed to simulate storm surge due to this 20th century hurricane within the model. This included water level information and bathymetry /topography (pre hurricane barrier construction). By inputting limited data, numerical modeling was capable of representing these complex phenomena.

RMA 2 was used to model the storm surge hydrodynamics due to the hurricane, while RMA 4 was used to simulate the advection/dispersion of the pollutants. These models are finite element models that describe the two dimensional, depth integrated hydrodynamics and pollutant transport, respectively.

RMA 2 modeling consisted of model set up and scenario simulations. Model set-up included generating a finite element grid describing the study area; it included the Acushnet River, New Bedford Harbor, Clarks Cove, Apponagansett Bay, a portion of Buzzards, and the upland area up to +20 feet (MSL). The upland area was included to account for the expected flooding due to the storm surge (+12 feet MSL). Bathymetric and topographic elevations were interpolated to the mesh and a boundary condition of water level , including the surge, was prescribed along the offshore boundary. With this data input, hydrodynamics due to the surge were quantified. One of the most prominent observations due to the surge was the immense flooding of the upland area. Although various scenarios were run to test the model’s sensitivity, the storm surge dominated the water flow.

From these results and with pollutant input data, pollutant transport modeling runs were simulated. Pollutant mass rate, duration of release, and time of release were input into the model. Pollutants were released from a specific area to quantify the transport pathways and concentrations caused by the hurricane’s storm surge.