Trent-Severn WaterwayTrent-Severn WaterwayNational Historic Site of CanadaNational Historic Site of Canada

Water Management ProgramWater 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

1 Set winter stoplog settings at most dams.

2 Use snow survey results and other data to show whether early refilling

is necessary.

3 Monitor the spring rise of the lakes and adjust the dams accordingly.

4 Aim to have the lakes full by the end of Spring.

5 Draw water according to the need for navigation (equal percentage

basis). A computer model is utilized to aid this process.

6 Set the dams to their winter settings in the fall.

Annual Cycle of Operation - Kawartha Lakes

1 Draw down on the larger lakes commences January 1.

2 Snow surveys are conducted weekly.

3 Mid February decision point.

4 Spring Freshet begins, lakes are refilled with snowmelt and rainfall.

5 Try to maintain minimum flows in the Spring for the walleye spawn.

6 Lake levels must be maintained using water from the reservoirs.

7 After navigation, most smaller lakes are lowered in preparation for winter.

Data CollectionLevel 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.