Synthesis of Science in South‐Eastern Georgian Bay and the Nottawasaga Valley Watershed Conducted Under the Lake Simcoe South‐Eastern Georgian Bay Clean Up Fund 2012‐2017 A report prepared by Zoey Duggan and Patricia Chambers for Environment and Climate Change Canada 2017 EXECUTIVE SUMMARY .................................................................................................................................. 3 1.0 INTRODUCTION ...................................................................................................................................... 7 2.0 BACKGROUND ...................................................................................................................................... 10 3.0 NUTRIENT DYNAMICS AND ECOSYSTEM FUNCTIONS FOR SOUTHERN GEORGIAN BAY (NOTTAWASAGA BAY) ................................................................................................................................ 16 3.1 NUTRIENT DELIVERY FROM THE NOTTAWASAGA RIVER WATERSHED ........................................... 16 3.2 NUTRIENT DELIVERY FROM THE BEACHES ALONG NOTTAWASAGA BAY ........................................ 20 3.3 MODELING AND FORECASTING THE FATE OF PHOSPHORUS .......................................................... 22 3.4 PHYTOPLANKTON AND HARMFUL ALGAL BLOOMS ........................................................................ 23 3.5 SCIENCE SUMMARY AND RECOMMENDATIONS .............................................................................. 23 4.0 NUTRIENT DYNAMICS AND ECOSYSTEM FUNCTIONS FOR EASTERN GEORGIAN BAY EMBAYMENTS 26 4.1 HYPOXIA AND ITS CAUSES ................................................................................................................ 27 4.2 PHOSPHORUS DYNAMICS ................................................................................................................. 28 4.3 PHYTOPLANKTON AND HARMFUL ALGAL BLOOMS ......................................................................... 32 4.4 MODEL BUILDING AND FORECASTING ............................................................................................. 35 4.5 SCIENCE SUMMARY AND RECOMMENDATIONS .............................................................................. 37 5.0 FLUCTUATING WATER LEVELS, WETLANDS HEALTH AND FISH POPULATIONS ................................... 40 6.0 ADVANCEMENT OF BASELINE DATA COLLECTION AND MONITORING ............................................... 44 6.1 IMPROVEMENTS TO WATER QUALITY MONITORING ...................................................................... 44 6.2 IMPROVEMENTS TO BASELINE DATA AND MAPPING ...................................................................... 49 7.0 RECOMMENDATIONS AND SCIENCE GAPS .......................................................................................... 53 7.1 MANANGEMENT RECOMMENDATIONS .......................................................................................... 53 7.2 SCIENCE GAPS .................................................................................................................................. 54 7.3 SUMMARY ........................................................................................................................................ 54 8.0 REFERENCES ......................................................................................................................................... 56 9.0 APPENDIX ONE: RESEARCH AND MONITORING PROJECT SUMMARIES ............................................... 60 1 LIST OF FIGURES Figure 1. Geographic scope of Lake Simcoe Georgian Bay Clean Up Fund.. ................................................. 8 Figure 2. Total phosphorus concentration for sampled locations from the Georgian Bay Water Quality Study (2003‐2005) by the MOE ................................................................................................................... 11 Figure 3. Scope of research projects undertaken in the Nottawasaga watershed and southern Georgian Bay ............................................................................................................................................................... 16 Figure 4. (a) Soluble reactive phosphorus (SRP) concentrations observed along Wasaga Beach (2013) (b) SRP concentrations in the groundwater. ............................................................................................... 21 Figure 5. Dispersal of the Nottawasaga River plume: (a) modeled using ELCOM, and (b) photographed from a drone. .............................................................................................................................................. 23 Figure 6. Scope of research projects undertaken in embayments along southeastern Georgian Bay. ..... 26 Figure 7. (a) Volume‐weighted oxygen concentrations in the hypolimnia of Basins, (b) inset map shows locations of basins. ...................................................................................................................................... 27 Figure 8. The ratio of hypolimnetic volume to surface area of the sediment‐water interface (VH:ASWI) , a good predictor of the mean dissolved oxygen consumption rate. ........................................................... 28 Figure 9. Nitrogen (N) and carbon (C) compositional analysis of sediments from (a) North Bay and (b) Tadenac Bay ........................................................................................................................................... 33 Figure 10. Distribution of phytoplankton with depth in South Bay in July 2014 ........................................ 35 Figure 11. Predicted and observed total phosphorus concentrations at stations In Honey Harbour, North Bay, South Bay from June 2014 – November 2015 .................................................................................... 36 Figure 12. Monthly and yearly mean water levels 1918‐2016 for Lake Huron‐Michigan .......................... 40 Figure 13. A screenshot of the Georgian Bay Biosphere Reserve, State of the Bay nutrient water monitoring website ..................................................................................................................................... 45 Figure 14. (a) Flight line indicating shoreline coverage of oblique imagery; (b) orthogonal image, and (c) the same location show as an oblique image ............................................................................................. 50 Figure 15. Bathymetry and sub‐bottom profiling, Sturgeon Bay ................................................................ 51 LIST OF TABLES Table 1. Annual total phosphorus loads (kg/year) for select tributaries to the Nottawasaga River. ......... 19 Table 2. Comparison of phosphorus loads entering Nottawasaga Bay from the Nottawasaga River. ....... 22 Table 3. Estimated annual loads of total phosphorus from major sources discharging to the North‐South embayment system ..................................................................................................................................... 31 Table 4. Summary of monitoring, and monitoring component of research projects in Georgian Bay and surrounding watersheds conducted under the LSGBCUF........................................................................... 47 2 EXECUTIVE SUMMARY To address public concerns about impaired water quality (particularly the presence of algal blooms) and meet commitments to protect ecosystem health under the Great Lakes Water Quality Agreement, Environment and Climate Change Canada initiated the Lake Simcoe South‐Eastern Georgian Bay Cleanup Fund (LSGBCUF) in 2012. The goals of the LSGBCUF were to improve monitoring and research of phosphorus sources, fate and impacts and promote ecosystem restoration and remediation in the watersheds of Lake Simcoe and the Nottawasaga Valley as well as the geographic area encompassing the shores of south‐eastern Georgian Bay (i.e., from the French River in the north, highway 400/69 to the east and south to Port Severn, including the Severn River and Lake Couchiching). Over the program’s five year span (2012‐2017), the LSGBCUF supported 106 projects led by provincial and federal governments, First Nations, universities, conservation authorities and citizen science groups at a total expenditure of $24 million. The objective of this report was to synthesize the science outcomes of the 35 research and monitoring projects funded under the 2012‐2017 LSBGCUF and conducted within the geographic boundary of south‐eastern Georgian Bay. The aim of these projects was to improve understanding of nutrient dynamics (especially phosphorus dynamics) and associated ecosystem functions of Georgian Bay waters, with a particular focus on the Nottawasaga River watershed and its receiving water, Nottawasaga Bay, and the embayments on eastern Georgian Bay. New science findings are summarized and information that can inform decision and policy making is identified, with projects grouped thematically, and in some cases, regionally (Nottawasaga Bay and coastal embayments). The goal of research projects undertaken in the Nottawasaga River watershed and the nearshore area of southern Georgian Bay was to identify potential sources and transport pathways of phosphorus to Nottawasaga Bay, and evaluate the fate of phosphorus once delivered to the Bay. Studies on the Nottawasaga River watershed showed that water quality is generally considered impaired along the entire length of the river. While the percentage of pasture land in the