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United States Department of Agriculture

Agricultural Research Service

Research Project: Modeling Nearsore Bacterial Fate and Transport in the Manitowoc River Plume in Lake Michigan

Location: Environmental Microbial and Food Safety Laboratory

2013 Annual Report


1a.Objectives (from AD-416):
Create and test a nearshore hydrodynamic model of Lake Michigan in the vicinity of the Manitowoc River. The nearshore model, which will extend upstream into the Manitowoc River, will be coupled to and forced by a larger lake-wide circulation model of Lake Michigan. Both models will be based on the unstructured grid model FVCOM. Identify all inputs to and outputs from the FVCOM flow and transport models in order to facilitate linkages with watershed and risk assessment microbial water quality models. Test the near-shore models for hydrodynamics and bacterial transport using available E. coli data.


1b.Approach (from AD-416):
Models will be developed for the Manitowoc River discharging into Lake Michigan. The three-dimensional FVCOM model will be used to describe both large-scale (that is, lake-wide) and nearshore aspects of flow and transport. The nearshore grid will extend into the upstream river segments to include the USGS gauge and other points of interest to ARS. High-resolution bathymetry and meteorological forcing datasets will be interpolated to model grids to create input files for the flow modules in FVCOM. Similarly bacterial loading from the river will be used in the form of time series data to define upstream boundary conditions for the transport models. E. coli monitoring data supplied by ARS will be used to test models. Plume dynamics and flow reversals which impact E. coli transport will be described by the models. Interface protocols and dictionaries for FVCOM and time series of microbial densities and hydrodynamics at selected locations (e.g., Read Arrow Park Beach) will be made available to be used for later analyses.


3.Progress Report:

The cooperator has evaluated data (provided by ARS, USGS, and EPA) on flow and on Enterococci transported in Manitowoc River water discharging into Lake Michigan. A three-dimensional FVCOM model was applied to describe nearshore aspects of flow and microbial transport. The nearshore grid was extended into the upstream river segments to include the USGS gauge and other points of interest to ARS. High-resolution bathymetry and meteorological forcing datasets were interpolated to model grids to create input files for the flow modules in FVCOM. Bacterial loading from the river was used in the form of time series data to define upstream boundary conditions for the transport models. E. coli and Entecocci monitoring data were used to test models. Plume dynamics and flow reversals which impact E. coli transport were described by the models. Interface protocols and dictionaries are under development to interface FVCOM with the USDA-ARS model SWAT that is capable of handling overland bacterial fate and transport.


Last Modified: 8/21/2014
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