Update – The Drawdown Begins

Parks Canada – TSW has Posted a New Water Management Update and the first Drawdown Forecast of the Year. (see links below)

The first Drawdown Forecast of 2020 indicates that all reservoirs will begin to experience declining water levels over the next two week period. Several reservoirs will see declines of as much as 25 cms or 10 inches.

This spring the snowpack was normal in March but it melted very early with peak flows in late March and early April. In order to protect against the risk of flooding from extreme spring rainfall events like have occurred in several recent years, the TSW water management team adopted the strategy of only filling reservoirs to 90% of full and then allowing levels to come up with spring rainfall. Because of the dry spring many reservoirs did not get to their full levels or close to full until mid or late June.

As of last week all reservoirs had risen to be near normal levels for this time of year. But we are in a significant drought across the entire Trent Basin. April and May and now June have all been months with less than normal precipitation. The deficit for May and June is at least 25% less than normal and conditions are very dry with very little inflow to our lakes. There have been some exceptional thunderstorm rainfall events localized to a few areas in the reservoirs but the localized rainfall has not impacted inflows and lake level much. The dry conditions extend all the way south to the lower Trent River.

TSW has already reduced the flow on the Otonabee River at Peterborough to its minimum level to conserve water throughout the Trent River basin. Travelers may have noticed the very low minimum flows controlled by the dams at crossings like Bobcaygeon, Buckhorn and Burleigh Falls. We are facing a situation quite like or potentially more extreme than we did in 2016, when we experienced two months without significant rainfall. The flows on the Gull and Burnt rivers are now being regulated to provide just the minimum flow required to offset evaporation and maintain minimum levels and minimum flows downstream.

Beginning this week we expect to see a slow drawdown on all reservoirs. In the Central Lakes, Eels Lake saw log operations begin last week, and Crystal and Mississagua lakes will see log operations begin a drawdown this week increasing flows on their downstream rivers which have had very low flows and levels.

As we head into July the long range weather forecast is not yet showing major precipitation events. However we will need a major general rainfall across the whole of the Trent Basin to allow the water management regime to begin to return to more normal conditions.

The TSW Drawdown forecast for the next two weeks can be accessed here.

The TSW Water Management Update can be accessed here.