Water Management Across TSW Reservoirs: Review of 2019

1. Overview of the TSW And Review of 2019 Winter and Spring Weather and Water Management Across the TSW Reservoirs with Focus on Mississagua Lakes CCRAI Meeting – June 22, 2019 Ted Spence CCRAI Board member; Chair CEWF and Professor Emeritus in Environmental Studies York U. 1

2. CEWF Background • A Volunteer Organization established in 2006 to provide input to - Panel on the Future of the Trent Severn Waterway (2007) • Aims to represent the interests of more than 30,000 waterfront property owners on “Reservoir” and “Flow-Through” (RaFT) lakes in Haliburton and Northern Peterborough Counties • 32 Member Lake Associations Including CCRAI representing 91% of the TSW’s reservoir lake storage capacity (reservoirs with no association = 3%) • Sub-watersheds included: • Gull, Burnt & Mississagua Rivers plus Nogies, Eels & Jack’s Creeks • In 2016 entered a new partnership with 6 local municipalities in Haliburton and Peterborough Counties, the Upper Trent Water Management Partnership (UTWMP). 2

3. CEWF Objectives • To promote an Integrated Approach to Water Management at the Watershed Level • To maintain dialogue with TSW management • To promote shared information and understanding of Water Management issues/practices • To promote approaches to ensure safe navigation, access to waterfront property, economic sustainability and the avoidance of negative environmental and economic impacts for residents on the Reservoir and Flow Through (RAFT) lakes.

4. Cewf.caLinks to TSW and CEWF News, TSW Water Levels, Water Management Updates and Level Forecasts

5. The Trent Watershed & the Trent-Severn Waterway • Trent River watershed is the largest in Southern Ontario with drainage area of 12,530 sq. km. covering 3 sub-watersheds. • The Haliburton Sector Reservoir Lakes – (3,320 sq. km.) • The Kawartha Lakes & Otonabee River - (4,862 sq. km.) • Rice Lake, the Trent River & Crowe River – (4,348 sq. km.) • Main feature of the watershed is the Trent-Severn Waterway which stretches 386 km from Georgian Bay to Lake Ontario and includes 45 locks from #1 Trenton to #45 Port Severn. 5

6. The Trent-Severn Watershed(Source: Parks Canada Water Levels Website)

7. Reservoir & Flow-Through (RAFT) Lakes • In the “Haliburton Sector” (Haliburton County and northern Peterborough County) there are 35 reservoirs – • 17 in the Gull River system (23,669 ha-m storage), • 13 in the Burnt River System (7,609 ha-m storage), and • 5 in the Central Lakes area (12,388 ha-m storage) including the Mississagua chain of lakes, Anstruther , Eels, Jacks and Crystal lakes. • The reservoir seasonal water level changes of up to 10 feet (3.4 m) combined with severe flow constraints at some points downstream (e.g. Minden, Peterborough) • There are also challenges to maintaining navigable water levels on connecting rivers and flow-through lakes and minimum flows and levels for fisheries management.

8. Trent River System Flow Chart(Source: Parks Canada 2013)

9. Key Water-Flow & -Level Constraints • TSW priorities public safety (flood management and water supply) and canal navigation; • Minimum flow at Peterborough for water supply and sewage treatment; • Maintaining the Canal Regulations draught limits is understood to govern the drawdown from the reservoirs; • While maintaining reservoir levels within historic norms • MNR Fisheries constraints in spring (walleye) and fall (lake trout) based on limited data for many lakes; • The reservoirs are not a flood control system particularly in late spring and early summer!

10. Since 2016 TSW have taken Substantial Action To Make Water Management More Data and Analysis Driven • Added 5 real-time snow gauges to augment manual readings • Adopted enhanced weather forecasting based on AES satellite information • Monitor inflow/outflow water balances to understand groundwater storage • Adopted a precipitation/runoff model to provide inflows to lakes based on forecast precipitation and snowmelt • Adopted a routing model to forecast flows and water levels throughout the system

11. Recent Experience • In last three summers reservoir levels have been good for us but TSW has had to continuously adjust to and manage for extreme weather conditions each year. • 2016 extreme rain and flooding in March, record setting drought May to August. • 2017 early snowmelt, extreme rain early May, flooding and continuing excess rainfall. Higher than normal levels all summer and into fall. • 2018 extreme rain/snow/ice in April followed by drought conditions and spotty rainfall through to end of July with slow filling of some reservoirs in May and June and drawdown beginning in early July. Very wet August.

12. 2018 TSW Water Management Strategy • Objective until early May was to minimize flood risk with variable and extreme winter weather events. Daily water management decisions based on data on water levels, river flows, snowpack water content, and soil conditions. April 29th logs removed and levels drawn down quickly in anticipation of major rain event that did not materialize. • In early May objective shifted to filling reservoirs and canal lakes taking account of levels and forecast precipitation. Spotty rainfall and drought led to slow filling of some reservoirs especially Mississagua. • May to July 22nd drought management with minimum flow on Trent and Otonabee rivers. Reservoir drawdown began in early July. • From July 22 onward rains returned and levels managed towards October Minimums.

13. 2018 Mississagua Lake Water Levels

14. 2019 Winter/Spring Precipitation Haliburton

15. 2019 Mississagua Lakes Water Management Experience • Dam remained at winter setting throughout March and April. • Higher than normal snowpack combined with April rainfall resulted in exceptional reservoir filling to above full with logs still out. • Same conditions applied throughout Trent Basin - too much water and storage full. Canal opening delayed because of high water and flows. • Strategy at Mississagua through May and into June was to pass as much water as possible while reacting to rainfall to avoiding flooding. High river flows and active log operations. • In mid June some logs still out as they work to manage level back down to normal range. However we have has 92% of normal rainfall in first 15 days • Serious shoreline erosion issues on the lakes because of above normal levels and boat wakes.

16. 2019 Mississagua Lake Levels

17. 2019 Mississagua Lake Levels Table

18. Example of Kawartha Lakes’ Levels 2019

19. Comparison of Four Recent High Water Events

20. 2019 Summary Conclusions • With climate change it appears that the year to year variability is increasing and we are seeing more extreme events. • TSW now has much more data at hand and analysis capacity than only a few years ago. • TSW bases operations on daily analysis with flood mitigation top priority in Spring. • In 2019, even with 3.5 times the normal snowpack at end of March and 180% of normal rain in April the flood levels were less than in 2017. Extreme flooding avoided in all areas. High water levels persist throughout Basin.

21. What CEWF is telling Residents that they should be thinking about and doing • Be aware of the increased risk of extreme flood levels, potentially with ice on the lakes • Review your infrastructure and if appropriate make changes now – dock systems, electrical, boat storage • Be aware of increased risk of low lake levels earlier in the season and at levels not previously experienced. • Review infrastructure for low levels – water lines, access, boat mooring, etc.