Keywords

GEMSS, urbanization, impacts, hydrodynamics, water quality, mixing zone, probability plume

Location

Session H2: Water Resources Management and Planning - Modeling and Software for Improving Decisions and Engaging Stakeholders

Start Date

18-6-2014 2:00 PM

End Date

18-6-2014 3:20 PM

Abstract

The Lake Simcoe Region Conservation Authority (LSRCA) in partnership with the Nottawasaga Valley Conservation Authority (NVCA) has been interested in addressing the cumulative impacts of land use changes due to urbanization to two water bodies, the Nottawasaga River and Nottawasaga Bay. In order to assess these impacts, an Assimilative Capacity Studies (ACS) was planned for decision-making on land use. The ACS involved application of a comprehensive 3-D hydrodynamic and transport model called GEMSS®. The model was calibrated both for hydrodynamics (currents and drogue trajectories) and baseline water quality measurements. The model was then applied to simulate conditions which are representative of existing and future land uses. These land use values were derived through use of the CANWET model which was established as part of the overall ACS work. The CANWET results for existing and future land uses where river discharge and constituent concentrations would combine to present a maximum loading I maximum plume condition were considered. The calibrated model was then run to simulate all forms of each water quality parameters within the model region. "Probability envelopes" for TP and TN were developed that summarize the response of each model cell within the model domain to the changing conditions in the lake (currents, momentum and loadings). The model results were analyzed in relation to near, intermediate and far-field mixing of the river with the lake. Comparisons were made between the near-field and far-field plumes resulting from land use changes due to urbanization for TP and TN simulations. The simulations for TP showed that there were minimal differences in the near­ field and far-field mixing zones for existing and future land uses. The TN simulations showed that there is an extension in the probability of finding higher TN concentrations along the shore in the future, but that these increases are relatively small. The modeling approach and the models used in this study can be easily applied to another basin or lake provided all the loadings from land use is obtained from a watershed model like the one used in this study.

 
Jun 18th, 2:00 PM Jun 18th, 3:20 PM

Evaluation of Urbanization and Impacts on Water Quality in Nottawasaga Bay Using an Integrated 3-D Modeling Framework

Session H2: Water Resources Management and Planning - Modeling and Software for Improving Decisions and Engaging Stakeholders

The Lake Simcoe Region Conservation Authority (LSRCA) in partnership with the Nottawasaga Valley Conservation Authority (NVCA) has been interested in addressing the cumulative impacts of land use changes due to urbanization to two water bodies, the Nottawasaga River and Nottawasaga Bay. In order to assess these impacts, an Assimilative Capacity Studies (ACS) was planned for decision-making on land use. The ACS involved application of a comprehensive 3-D hydrodynamic and transport model called GEMSS®. The model was calibrated both for hydrodynamics (currents and drogue trajectories) and baseline water quality measurements. The model was then applied to simulate conditions which are representative of existing and future land uses. These land use values were derived through use of the CANWET model which was established as part of the overall ACS work. The CANWET results for existing and future land uses where river discharge and constituent concentrations would combine to present a maximum loading I maximum plume condition were considered. The calibrated model was then run to simulate all forms of each water quality parameters within the model region. "Probability envelopes" for TP and TN were developed that summarize the response of each model cell within the model domain to the changing conditions in the lake (currents, momentum and loadings). The model results were analyzed in relation to near, intermediate and far-field mixing of the river with the lake. Comparisons were made between the near-field and far-field plumes resulting from land use changes due to urbanization for TP and TN simulations. The simulations for TP showed that there were minimal differences in the near­ field and far-field mixing zones for existing and future land uses. The TN simulations showed that there is an extension in the probability of finding higher TN concentrations along the shore in the future, but that these increases are relatively small. The modeling approach and the models used in this study can be easily applied to another basin or lake provided all the loadings from land use is obtained from a watershed model like the one used in this study.