Forecasting and monitoring improvements in the Ashbridges Bay Coastal Zone from the ABTP Project

Session: 55. - Solutions for Lake Ontario: Addressing the Human Footprint on Regional Water Quality

Bill (William) Snodgrass, City of Toronto, wsnodgr@toronto.ca
Todd Howell, Ontario Ministry of the Environment, Env. Monitoring & Reporting Br, todd.howell@ontario.ca
Fiona Duckett, W.F. Baird & Assoc. Coastal Eng. Ltd., duckett@baird.com
Raymond Dewey, Modelling Surface Water Ltd., rdewey@pathcom.com
Susan Atlin, City of Toronto, susan.atlin@toronto.ca

Abstract

 A new outfall is proposed for the Ashbridges Bay Treatment Plant(ABTP), Toronto’s largest wastewater treatment plant, to address infrastructure related limitations in the existing outfall. The MIKE3 platform was used to forecast the spatial changes in total phosphorus concentrations [TP], after extensive calibration studies with observed temperature, current vectors at 5 locations, and [TP]. The paper will discuss the approaches used for assessing the degree of fit in model calibration studies. The new outfall is predicted to reduce the nearshore TP levels, results in a small dispersion zone, and supports the Toronto and Region Remedial Action Plan. The new outfall, positioned near the limits of the coastal zone, will deliver nutrients more directly to the deeper offshore waters, contributing to minimizing the oligotrophication of the deeper waters. Based on the spatial changes in forecast [TP] in Ashbridges Bay, a proposed MOECC design for spatial monitoring during the intensive 2018 CSMI sampling year for Lake Ontario is presented, which will provide baseline information for long term monitoring studies to document future improvements in water quality. 

1. Keyword
lake management

2. Keyword
eutrophication

3. Keyword
coastal processes

4. Additional Keyword
infrastructure project

5. Additional Keyword
modelling

6. Additional Keyword
monitoring