Hydrodynamic Modeling of Saco-Casco Bays, the Damariscotta River and Eastern Maine
Project Description
The coast of Maine is highly variable in terms of both geomorphology and levels of coastal development. Among SEANET bioregions, the Saco-Casco Bay areas have the highest human population density in the state. The Cobscook Region (Downeast) has little coastal development and low population densities. Understanding the detailed circulation patterns and consequent temperature, salinity, and nutrient distributions, as well as the movement of water-borne pathogens/detritus, is essential to coastal planning. For example, temperature and current speeds are important drivers of bivalve growth in aquaculture systems. Too little flow through an aquaculture system results in reduced food delivery to animals in the middle of the floats/rafts and temperature is a key factor that affects metabolism.
The modeling group is using coupled hydrodynamic and biogeochemical models to determine carrying capacity in three study sites; the Damariscotta estuary, Saco Bay, and Casco Bay.
Results and Accomplishments
Using high-resolution bathymetry and in situ measurements including data from the SEANET buoy network, project personnel are developing two circulation models, one for Saco-Casco bays and another for the Damariscotta estuary. These models will form the basis for detailed biogeochemical models as well as growth and siting simulations of these areas. The base model code is the Finite Volume Coastal Ocean Model (FVCOM), an unstructured grid, three-dimensional coastal circulation model capable of simulating wetting and drying of tidal flats. The models are forced with the runoff from rivers as well as the oceanic conditions from the North East Coastal Ocean Forecast System (NECOFS) at the open boundary. Project personnel conducted short-term simulations of the circulation in Saco and Casco Bays and compared the modeled water level with tide gauge observations. Simulations of 2016 through 2017 were planned but were terminated due to errors found in the NECOFS provided open boundary condition. The hydrodynamic model for the Damariscotta Estuary experienced the same open boundary issue. Project personnel are working with the NECOFS developer to resolve this issue. The most significant accomplishment in 2017-2018 for this project team is the development of a coupled wave-circulation model for Saco and Casco Bays.
Summary of Data Being Collected
| Data | Type | Quantity | Location |
| Bathymetric Data (25 cm Resolution) | Triple-beam side-scan sonar | 3 data-sets | Bagaduce River, Saco Bay, Damariscotta River |
| Buoy Observations at 1m: temperature, salinity, dissolved oxygen, pH, chlorophyll-a, CDOM, turbidity, current velocities, PAR, Nitrate | Field | Hourly | Saco and Casco Bays and Damariscotta River |
| Buoy Observations at 2m, 5m, 10m, 15m, and 25m: temp, salinity. Current velocity (all depth), chlorophyll-a (5m only) | Field | 15 minutes | Mouth of Saco and Casco Bays and Damariscotta River |