RESTORING THE CONNECTION BETWEEN CREEK AND LAKE: FRESH WATER ESTUARINE CREATION IN MISSISSAUGA

Transcription

1 RESTORING THE CONNECTION BETWEEN CREEK AND LAKE: FRESH WATER ESTUARINE CREATION IN MISSISSAUGA Jeff Doucette, Kenneth Dion and Sally-Beth Betts 6 th International Conference on Natural Channel Systems Guelph, ON May 24 th, 2018

2 Acknowledgments Region of Peel Credit Valley Conservation Toronto and Region Conservation Authority

3 Presentation Overview Introduction to the Lakeview Waterfront Connection Project Introduction to Serson Creek Freshwater Estuaries Opportunities and Constraints for Serson Creek Design Construction Challenges

4 Introduction to the Lakeview Waterfront Connection Project

5 Introduction to the Lakeview Waterfront Connection Project

6 Introduction to the Lakeview Waterfront Connection Project

7 Introduction to the Lakeview Waterfront Connection Project Produced by Brook McIlroy

8 Introduction to the Lakeview Waterfront Connection Project Produced by Brook McIlroy

9 Introduction to Serson Creek Outlet for Serson Cr

10 Introduction to Serson Creek

11 Introduction to Serson Creek

12 Introduction to Serson Creek

13 Introduction to Serson Creek

14 Introduction to Serson Creek

15 Freshwater Estuaries Semi-enclosed areas of lake shoreline where lake water mixes with water from tributaries of the lake Chemically distinct combinations of river and lake water Mixing is storm driven: Surges Seiching River flow Source: NOAA Ocean Service Education: Freshwater Estuaries (July 6, 2017)

16 Opportunities and Constraints for Serson Creek Design Design consisted of 4 main components: 1. Stormwater corridor enhancement 2. Estuary Channel 3. Outlet through Shoreline Revetment 4. Connection details between coastal wetlands and estuary channel

17 Opportunities and Constraints for Serson Creek Design Stormwater corridor opportunities: Widen stormwater corridor Direct base flow and bankfull down the corridor and increased connectivity to the lake Enhance existing aquatic habitat through formalization of a low flow and bankfull channel Create pool-riffle habitat features Stormwater corridor constraints: Widened channel still confined Limited sediment transport from upstream Stabilization will still be required No increase in flood potential

18 Opportunities and Constraints for Serson Creek Design Estuary channel design opportunities: Re-connect watercourse to the lake increasing fish passage potential Create fresh water estuary Create wetlands Link wetlands to the lake Carp control gate for fish access to wetlands in Cells 1 and 2, and water level control Control overtopping into wetlands Estuary channel design was guided by the following criteria: Match existing grades Lake level controls tie-in location No increases in upstream flood levels Narrow width to maximize space for leveed wetland

19 Opportunities and Constraints for Serson Creek Design Outlet design was guided by the following criteria: Linkage at low water levels to fish gate at the levees Compatibility with the shoreline revetment design Levee overtopping must be above the 10-yr flow event Flushing events to clear the outlet of accumulated sediment and woody debris must be possible Pedestrian bridge crossing Access for fishing Low flow channel must be possible at low lake levels

20 Opportunities and Constraints for Serson Creek Design Shoals and pools High estuary hooks Rock habitat features Woody features Vegetated rock buttress Levees Connected wetland habitats

21 Construction Challenges

22 Construction Challenges

23 Construction Challenges

24 Construction Challenges

25 Construction Challenges

26 Sixteen Mile Creek

27 Habitat Art Photography by Annette Seip, December Cell 1 wetland habitat art.