Trent-Severn Waterway National Historic Site of Canada Water Management Program

Trent and Severn Watersheds

The outlet of the Severn River at Lock 45 in Port Severn The outlet of the Trent River at Lock 1 in Trenton

Water Management Program Priorities Navigation Mandate along the Canal System Green Energy Environment (Wildlife and the Fishery) Public Health and Safety Appropriate Water Levels and Flows for other uses

Competing Interests In the event of wet conditions: Public Safety can be endangered with increased water levels/flows. Resulting high flows can disrupt navigation along the waterway. High flows allow fish to spawn in elevated areas prone to declines. Excess spill at many hydro generating stations.

Competing Interests In the event of dry conditions: Public Health is not initially endangered, water quality. Navigation can be threatened as lake levels decline Fish spawn in shallow areas are in danger of being left dry. Reservoir lake levels drop more than normal. Hydro generation is diminished as water flow is reduced.

Annual Cycle of Operation – Reservoir Lakes 1Set winter stoplog settings at most dams. 2Use snow survey results and other data to show whether early refilling is necessary. 3Monitor the spring rise of the lakes and adjust the dams accordingly. 4Aim to have the lakes full by the end of Spring. 5Draw water according to the need for navigation (equal percentage basis). A computer model is utilized to aid this process. 6Set the dams to their winter settings in the fall.

Annual Cycle of Operation - Kawartha Lakes 1Draw down on the larger lakes commences January 1. 2Snow surveys are conducted weekly. 3Mid February decision point. 4Spring Freshet begins, lakes are refilled with snowmelt and rainfall. 5Try to maintain minimum flows in the Spring for the walleye spawn. 6Lake levels must be maintained using water from the reservoirs. 7After navigation, most smaller lakes are lowered in preparation for winter.

Data Collection Level gauges on the Kawartha Lakes, Haliburton Reservoirs, and the Severn River system 100 Manual Level Gauges (weekly/daily readings) 50 Automatic Level Gauges (daily readings) 12 Flow Gauges: rated level gauges, flow meters 11 Rainfall Accumulation Gauges

Snow Surveys Snow survey sites are laid out throughout the watershed to better anticipate the magnitude of spring melt water. Sampling tube is forced into the snow pack to measure depth Sampling tube is weighed to determine moisture content

Flooding…A Natural Event Upper Otonabee River: Frazil ice blocking the flow of the river causing flooding downstream of Peterborough. Dam at Lakefield: dams are wide open to pass high spring flows.

Lock 1 at Trenton: Sudden heavy rains and warm weather cause localized flooding. Healey Falls Dam: Extremely fast melt coupled with above average snowfall accumulation. Flooding…A Natural Event

Some Program Challenges Natural restrictions that impede flow Intense rainfall and snowmelt near Furnace Falls Log lifter and manual winches can slow response time

Summary The Trent-Severn Waterway NHSC: Considers the interests and needs of all stakeholders. Manages water levels/flows based on an annual cycle of operation and current conditions. It is important to understand that Mother Nature drives the Water Management Program on the TSW. We do our best to steer it but sometimes She has other ideas.