Map of Lac des Plaines with depth contours

Lac des Plaines

47.0702° N, 70.1223° W

Depth contours from the 2012 government survey. Not for navigation.

Download the depth map (SVG)

Lac des Plaines is 3.1 m deep at its deepest point, shallower than 97% of the 1,506 surveyed lakes in Quebec. It covers 0.59 km² and lies 7.2 km southeast of Saint-Jean-Baptiste.

Maximum depth
3.1 msurveyed 2012
shallower than 97% of the 1,506 surveyed lakes in Quebec
Area
0.59 km²
larger than 65% of the 29,407 lakes in Quebec
Shoreline
4.8 km
longer than 59% of the 29,407 lakes in Quebec
Water clarity
1.5 mSecchi depth, 2024
less clear than 94% of the 805 monitored lakes in Quebec
Elevation
390 m

Today on the water

8.6 °C

Wind SW 20 km/h

Observed at L'Islet, as of 3:00 a.m. EDT

choppy Estimated waves, next 12 hours: up to 0.2 m. Around 4 a.m., wind from the southwest: the southwest shore is sheltered, waves build toward the northeast shore.

Hourly forecast, next 24 hours
Time4 a.m.7 a.m.10 a.m.1 p.m.4 p.m.7 p.m.10 p.m.1 a.m.
Wind km/hSW 20SW 20SW 20SW 20SW 20SW 20SW 20SW 20
Gusts km/h40404040404040
Waves (est.) m0.20.20.20.20.2
Temp. °C98910111088
Precip. %3030303030000

Tonight: A few showers ending early this evening then mainly cloudy with 30 percent chance of showers. Risk of a thunderstorm early this evening. Wind southwest 20 km/h gusting to 40. Low 8.

Weather: L'Islet (local forecast), as of 3:05 a.m. EDT

Sun and moon

Civil dawn
6:19 a.m.
Sunrise
6:50 a.m.
Sunset
6:04 p.m.
Civil dusk
6:34 p.m.
Moonrise
5:39 a.m.
Moonset
5:22 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

11% of Lac des Plaines is shallower than 1 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 2012 records a maximum depth of 3.1 m, drawn from 11 depth contours.

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 Depths are from government surveys and may be outdated.

Water

Trophic status from the latest monitoring: eutrophic.

Clarity was measured with a Secchi disk in 17 years between 2008 and 2024; the latest annual mean is 1.5 m.

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