Northern Saskatchewan Summer High Water Update – July 30, 2020
July 30, 2020 -- Northern Saskatchewan has received extremely high cumulative precipitation since April 1, 2020, resulting in very high flows and lake levels across the Churchill River and Lower Saskatchewan River basins. Much of this rainfall has come in the months of June and July. As shown below, much of the central portion of the province has received record or near record precipitation over the past two months.
Rainfall over the past three days has been negligible over the Churchill and Lower Saskatchewan river basins where water levels are highest.
Flows and Lake Levels:
High river and lake levels can be expected for the remainder of summer and in some cases, such as the mainstem of the Churchill River, into the fall and winter. In most areas flows and water levels are expected to peak, or have peaked, slightly lower than previous historical highs. However, flows and levels in the Lower Churchill River, including Reindeer River and Churchill River near Sandy Bay, have exceed previous historical highs.
Below are specific conditions at various locations as well as projected future peak levels.
Ile a la Crosse:
Present elevation: 421.07 m
Estimated peak: 421.1 m on or near July 28, 2020
It appears as if levels at Lac Ile a la Crosse are at peak; however, they are expected to remain high for some time resulting in a risk of wind and wave action resulting in short-term higher levels.
Lac La Ronge:
Current elevation: 364.90 m
Projected peak: 364.97 m on or near August 20, 2020
With drier conditions over the last few days closer to Lac La Ronge and minimal precipitation over headwater areas over the past week, inflows appear to be near peak and lake level rises are also slowing in response. If conditions remain dry, the lake level will track in the lower portion of the confidence band shown on the hydrograph.
Present Elevation: 10.06 m (2370 m3/s)
Forecasted peak: 10.29 m (2460 m3/s) on or near August 4
SaskPower has begun to reduce outflows at the Whitesand Dam. This reduction will offset some of the higher flows arriving from further upstream.
- Spiritwood station received 14 mm of precipitation on July 25 (20 km N of Meeting Lake).
- Spiritwood has recorded 247 mm of Precipitation since April 1, 2020
- July 29, 2020, lake level is 739.48 m, which is unchanged from July 22.
- Outlet spill elevation is 739.23 m (25 cm lower than current lake level)
- Meeting Lake has reached its outlet and is confirmed flowing into outlet channel
- There is not significant flow moving through outlet currently as it is congested with thick vegetation.
- Berms around the lake should now be built to WSA recommended standard (739.83-740 m)
Present Elevation: 267.63 as of 8:00 AM July 27, 2020
Forecasted peak: Peak observed on July 24, 2020
With Cumberland Lake well into its recession and the threat of higher levels diminishing, it will not be included in future updates. Forecasted levels for Cumberland Lake are part of WSA’s 10-Day Saskatchewan River Forecasts which can be found here: https://www.wsask.ca/Lakes-and-Rivers/Provincial-Forecast/
Jan, Amisk, and Deschambault Lakes
- These lakes are an area of increasing concern with the significant rainfall over this area July 25-26.
- Our current expectation is for 2017 levels to be surpassed and for levels to approach those observed in 1974.
Aside from some scattered showers over southern areas of Saskatchewan’s boreal forest today, brining 5-10 mm of rain, drier conditions are expected to persist over the next five days.