Map of Lac Blue Sea with depth contours

Lac Blue Sea

46.2407° N, 76.0528° W

Depth contours from the 1980 government survey. Not for navigation.

Download the depth map (SVG)

Lac Blue Sea is 59.8 m deep at its deepest point, deeper than 96% of the 1,506 surveyed lakes in Quebec. It covers 14.2 km² and lies beside Orlo.

Maximum depth
59.8 msurveyed 1980
deeper than 96% of the 1,506 surveyed lakes in Quebec
Area
14.2 km²
larger than 96% of the 29,407 lakes in Quebec
Shoreline
46.6 km
longer than 95% of the 29,407 lakes in Quebec
Water clarity
7.3 mSecchi depth, 2025
clearer than 93% of the 805 monitored lakes in Quebec
Elevation
165 m

Today on the water

6.2 °C

Wind W 3 km/h, gusts 29

Observed at Maniwaki, as of 2:00 a.m. EDT

choppy Estimated waves, next 12 hours: up to 0.3 m.

Hourly forecast, next 24 hours
Time3 a.m.6 a.m.9 a.m.12 p.m.3 p.m.6 p.m.9 p.m.12 a.m.
Wind km/hW 10NW 10NW 20NW 20NW 20NW 10var. 5var. 5
Waves (est.) m0.10.10.30.3
Temp. °C6561011952
Precip. %6030303030000

Tonight: Partly cloudy with 60 percent chance of showers. Wind west 20 km/h becoming light early this evening. Low plus 5.

Weather: Maniwaki (local forecast), as of 2:02 a.m. EDT

Sun and moon

Civil dawn
6:43 a.m.
Sunrise
7:13 a.m.
Sunset
6:28 p.m.
Civil dusk
6:58 p.m.
Moonrise
6:04 a.m.
Moonset
5:47 p.m.
Moon
Waning crescent, 1% lit

Data Source: Environment and Climate Change Canada. Local times.

How waves are estimated

Significant wave height from the forecast hourly wind and the open-water distance (fetch) upwind, using the SMB method (US Army Corps of Engineers Shore Protection Manual, 1984), rounded up to the next 0.1 m. It is not a measurement: gusts, leftover swell and shoals can make water rougher. Under 0.2 m: calm; 0.2–0.5 m: choppy; over 0.5 m: rough.

Depth

8% of Lac Blue Sea is shallower than 3 m, and 20% is deeper than 30 m.

How to read it: the lake’s area is sorted from the shore to the deepest point. Where the curve is flat, large areas share one depth (flats and weed beds); where it drops, depth changes quickly (drop-offs).

The government depth survey from 1980 records a maximum depth of 59.8 m, drawn from 280 depth contours.

Not for navigation. Depths are from government surveys and may be outdated.

Water

Trophic status from the latest monitoring: oligotrophic.

Clarity was measured with a Secchi disk in 22 years between 2004 and 2025; the latest annual mean is 7.3 m.

Water clarity (Secchi depth, m)
Total phosphorus (µg/L)