The Water Management Program
The Trent-Severn Waterway is a 386-kilometre inland canal system crossing central Ontario from Trenton on the Bay of Quinte to Port Severn on Georgian Bay. Natural rivers and lakes are connected by canal cuts, locks, and dams to form a navigable route through two neighbouring watersheds – the Trent and the Severn. There are three key components to the Waterway: the Trent River watershed, the Reservoir Lakes, and the Severn River watershed (Figure 1
). The characteristics of the three components are summarized here and described in more detail in fact sheets provided as appendices.
Figure 1. Watersheds of the Trent-Severn Waterway© Parks Canada
Runoff and Evaporation
Runoff rates and evaporation losses are determined by the characteristics of the lands in the watersheds and weather conditions.
South of the Shield
- Primarily rock and shallow soils
- Rapid runoff
- Less evaporation due to deeper lakes
- Deeper soils
- Slower runoff: depending on the time of year, only about 25% of precipitation appears as runoff flows
- Greater evaporation due to shallower lakes with larger surface
The Trent River watershed drains to Lake Ontario. The river basin has an area of 12,200 square kilometres and includes the reservoir lakes. Approximately one third of the basin lies in the Canadian Shield, with the other two thirds in the rolling farmlands of southern Ontario. The Trent River basin contains the Kawartha Lakes: Rice, Katchewanooka, Clear, Stony, Lovesick, Lower Buckhorn, Buckhorn, Chemong, Pigeon, Sturgeon, Scugog, Cameron and Balsam. These lakes lie primarily south of the Canadian Shield in rolling countryside, where rainfall runoff is usually slow and evaporation losses in the summer are high. The Otonabee and the Trent are the two primary rivers, with the Otonabee connecting Katchewanooka Lake and Rice Lake and the Trent connecting Rice Lake and the Bay of Quinte.
The Reservoir Lakes to the north consist of forty-four lakes in the Haliburton Highlands area that are dammed to collect spring runoff water. Water from the Reservoir Lakes is released over the summer to supply the Trent component of the Waterway. These lakes lie in the Precambrian Shield on the tributaries of the Gull, Burnt, and Mississagua River, as well as Nogies, Eels, and Jack Creek. The drainage area of the Haliburton tributaries (Gull and Burnt River) is in the order of 3,200 square kilometres.
The Severn River watershed
lies immediately west of the Trent River watershed and drains into Georgian Bay. This 6,160 square kilometre drainage area has three major components:
- The Lake Simcoe and Couchiching basin, including the Talbot River
- The Black River watershed that feeds into the Severn River downstream of Lake Couchiching
- The lakes and channels of the Severn River below Washago, including Sparrow Lake, Six Mile Lake and Gloucester Pool
Most of the drainage area for the Lake Simcoe-Couchiching basin is in the rolling farmland and deeper soils characteristic of the southern area. As a result, water run-off is slow and evaporation losses from both land and lake surfaces are high.
The Black River watershed, located in the thin soils and rock of the Precambrian Shield, is virtually unregulated and produces rapid run-off of precipitation with lower evaporation losses. Consequently, even though the Black River watershed is less than half of the area of the Simcoe-Couchiching basin, its long-term average flow is comparable. The Black also has high peak flows during the spring period. The watercourses of the Black and the Severn Rivers contain numerous narrow sections and natural constrictions that increase water levels in the river and create upstream flooding during high flows.