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Issue 2019.4
What’s Happening Now ?

This newsletter is the fourth issue of 2019 and applies to the week of April 4th to April 10th.
MNRF advises that the current average snow water equivalent in the watershed is 192 mm which is an increase from their March 15th measurements. This amount of snow is almost as high as in 2013 when flooding was experienced in the watershed. It is also well above the triggers in the Muskoka River Water Management Plan. As a result, lake levels are being drawn down to the bottom of their Normal Operating Zone in anticipation of a large spring melt. This drawdown has been in progress since January 1st.

 As high water levels are likely due to the snowpack, residents are cautioned to make sure personal effects have been cleared from boat house floors and low lying areas of their property.

Future Weather
For the coming week, a few thawing days in the high single digits and rainfall under 10mm are forecast for Muskoka.  

Flooding Forecast
With gradual melting forecast in the coming week lake levels are expected to continue to gradually lower. Flooding is not expected due to the projected low impact, short duration of the thaw. 
Data for March 27th Lake Muskoka Lakes Rosseau & Joseph
Gauge [m] 8.82 8.55
Elevation [m] 224.77 225.67
Target Level [m]* 224.9 225.65
Normal Zone Range [m]* 224.6 to 225.75 225.4 to 226.25
Summer Zone Range [m]* 225.28 to 225.65 226.0 to 226.65
*Muskoka River Water Management Plan – Figures 12.3.1 and 12.3.2

In Figure 1 [below] lake levels are shown for the past year through April 4th. The right hand side of the graph shows water levels have lowered the past week and are within 3 inches of the level at this time last year. Drawdown of the lake continues with logs out at the Bala dams. Bala Bay water levels are about 8 inches lower than in the main lake due to flow restrictions around Bala Park Island. The current Lake Muskoka water level is about 6.5 inches short of the drawdown objective of bottom of the Normal Zone.

Flow through Bala is about 130 m3/sec. This is well below the 280 m3/sec flood flow for Bala Reach. Inflows from the North and South branches of the Muskoka River are currently 65 m3/sec, so combined inflows [including from upper lakes] are less than outflow and continued drawdown is expected this week.

Figure 1: Lake Muskoka – 2018/19 Water Levels [meters above gauge 02EB018 Beaumaris]

Figure 2 [below] shows lake levels for the past year through April 4th for the Upper Lakes.  Here drawdown is also actively in progress with a further lowering of 2 inches over the past week. Current water level remains about 2 inches short of last year’s low and 10 inches short of the bottom of Normal Zone.

Figure 2: Lakes Rosseau & Joseph – 2018/19 Water Levels [meters above gauge 02EB020 Port Carling]

Copyright © *2019* *Muskoka Lakes Association*, All rights reserved.

Our mailing address is:
65 Joseph St, Port Carling, ON P0B 1J0

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