Graph showing water level and discharge on Weslemkoon Lake, 2022.

Water levels report by director marty blake

Water Levels

Water levels on Lake Weslemkoon are maintained by the Ministry of Natural Resources and Forestry (MNRF). The MNRF does their best to follow the planned Madawaska Water Management Plan but are often constrained by how much water they can release from the lake as too much would damage the infrastructure downstream of Weslemkoon.

LWCA Director Marty Blake stays in contact with the MNRF, communicating any concerns about high or low water levels or the functioning of the dam.

We are always concerned about lake levels. As you may recall, in late April 2019, water levels were VERY high. Docs were under ice, and when as the considerable snow in the bush melted, the lake rose even higher. This caused all sorts of damage to boathouses and docks.

Nathan Hack from the MNRF gave the LWCA directors a tour of the dam in September 2022. There are a few things worth noting about the Dam:

The lake level plan is part of the larger Madawaska Water Management Plan involving many lakes and dams in the Madawaska River watershed.
The water level gauge measures the lake level in near real time and updates the MNRF regularly.
The plan, originally written in 2009, notes that summer levels are maintained by the Lake association. This is no longer the case and the MNRF monitors and adjusts throughout the year.
Due to an older, low bridge downstream in the McArthurs Mills area, the outflow of the dam is restricted to 34 cubic meters per second. Meaning unlimited amounts of water cannot be released from the lake when levels rise so as to protect the bridge.
Some lakes in the area have a specific draw down in the fall for Trout
spawning and then raise their levels again so as to protect the eggs early the next year. This is NOT the case with Weslemkoon. There is a slight draw down around Thanksgiving and then left there pretty much until the spring.
In March there is a significant draw down to prepare for spring runoff.
There are 9 logs in the dam and a spare that is left on top.

Water Levels Graph (above)

The graph at the top of this section was produced and shared by Nathan Hack who works with the MNRF. He gave several of the LWCA Directors a tour of the dam in mid September 2022.

Looking at the chart, you can see that the blue is the actual lake level and the green line is the target level. (The blue line stops just prior to Sept. 15, as that's when the tour was.)

Feb 2, 2026 update:

From Nathan Hack (MNRF contact), via email:

"We had troubles with the (water level) gauge in the fall. We fixed it a few times briefly but it continued to give us headaches. We ended up getting an entirely different system as those are so old you can’t really get them anymore.

Long story short. The Data Garrison link you had from before will no longer work. The location where I viewed the water level data online is now an internal location that requires a government login.

Right now the water level is at 317.82 which is within our pretty tight winter range.

I'll see what I can do for getting a new link but I have a hunch it might be a difficult task."

Photo Credit: Steve Latto

Excerpts from Madawaska Water Management Plan

Below are a few excerpts from the Madawaska Water Management Plan and a water level discharge chart for this year as of Mid September:

The Weslemkoon Lake dam is in Ashby Township and is located towards the end of Weslemkoon Lake. Weslemkoon Lake flows into the Little Mississippi River.
The Weslemkoon Lake dam was originally a timber structure, but was replaced in the autumn of 1938 by a concrete structure. It was rebuilt in 1952 to better maintain the reservoir levels in Weslemkoon Lake.
The dam is a 3.8 m high by 16 m long with a single log sluice and two weirs. The log sluice is 4.9 m long with a sill elevation of 313.98 m CGD. Both weirs are 4.6 m long with a crest elevation of 316.89 m CGD. The overflow weirs are located to either side of the main spillway.
Water levels are maintained for recreation and for Lake Trout spawning in the fall. Flow releases are maintained below 34 m3s to protect a downstream bridge. A water level gauge is installed at the dam on the right wing wall.
The compliance framework for MNRF facilities in the Madawaska River watershed does not require the use of mandatory level or flow limits. The level of Weslemkoon Lake is usually maintained between 317.40 and 318.05 m CGD. The annual variation of the operating band is shown in Figure 9.14 on page 195 of the Management Plan.
The typical annual mode of operation of Weslemkoon Lake Dam is summarized in Table 9.24, page 194 of the Management Plan. We have reproduced the contents of this table immediately below.

Weslemkoon Lake Dam Operating Regime

The following information originated in the Weslemkoon Lake Dam Operation Plan, 1985, and was reproduced as Table 9.24 in the Madawaska Water Management Plan:

Spring
In anticipation of high flows, one to two weeks prior to the freshet the lake level
should be drawn down as slowly as possible yet succeed in providing at least an extra 0.3 m of additional storage below the summer minimum level. After spring freshet, the level should be in the upper portion of the summer range unless the watershed is saturated and/or rainfall is expected (lower portion of summer range should be used).Lake level should be maintained in late spring in its upper summer range by having approximately eight stop logs in the dam.

Summer
As the summer begins, eight to nine stop logs will be required to hold the water
level in the upper half of the summer range between 317.8 m and 318.05 m.

Fall
The lake should achieve its minimum summer level by the Thanksgiving weekend. By the end of October, a lake level of 317.8 m or lower should be achieved and held constant throughout the winter.

Winter

A log setting of six to seven logs should hold a level of 317.8 m.