Lake St. Francois-Xavier

Lake Saint-François-Xavier's tributaries

Lake Saint-François-Xavier is a lake in the Laurentians located in the village of Montfort, in the municipality of Wentworth-North. One travels approximately 80 km to get there from Montreal, by the Laurentian highway, then road 364 and finally the Chemin de Montfort.



If you're a resident of Montreal, like me, you may not have the right explanations on the process.  In spring, the winter ice cover on a lake starts to give way and sink when the temperature rises above zero Celsius. But ice floats on water, right? The undersigned had noticed this phenomenon and had rather thought that a layer of water had accidentally ended up on top of the ice, without being able to quickly regain its place under it. This was not the correct explanation.

Here are reported a few explanation on some of the interrelated phenomena based on temperature changes. The central point is that water is the densest at 4°C. Above or below this temperature, it is less dense, less heavy, and will tend to lodge above the water at 4°C.  In the spring, the temperature of the melting ice eventually reaches 1, then 2, then 3, then 4°C. If the water from rain or melting snow around this ice is warmer, it will cover the ice. This is the beginning of the show. (in french)

This anomaly, since one would expect a correlation in only one direction between the change in temperature and the change in water density, explains several phenomena. And why does the water at the bottom of our lakes stay at about 4°C, except for lakes that are too shallow, among other cases?

In winter, "because of this dilatometric anomaly, below a temperature of 4°C, cold surface water no longer conveys downwards, preventing deeper water from cooling". anomalie dilatométrique, Without this rule, the water in a lake could freeze to the bottom, preventing all aquatic life from surviving.

Furthermore, the temperature, and thus the density (or weight) of a lake's water, from the surface we understand, changes with the seasons. If it varies with depth, as it does in summer or winter, thus following a thermal stratification, the water does not tend to mix. However, when it reaches about 4°C at any depth, at some point in the spring or fall, a little bit can trigger what is called spring or fall mixing. The latter then causes a mixing of the elements present in the lake water.

Note: This is not a scientific treatise; the idea is to put the reader on the path to understanding the phenomenon.  The reader should seek a more rigorous analysis from competent sources.

Translated with (free version)

By Carl Chapdelaine

Lac-Thurson road on Google Earth:

Aid for rehabilitation of LSFX's dam?

In the spring of 2018, the Department of L’Environnement et la Lutte contre les changements climatiques announced investments of 45, 7 M$ for the upgrade of public (Government) and municipal dams. In a new financial assistance program for the upgrading of the municipal dams (PAFMAN), $ 13.7 of that amount would go to "financial support to municipalities which are owners of a high-capacity dam".

The dam at the foot of Lake Saint-François-Xavier seems to meet the criteria of the program and it has been, to our knowledge, identified as requiring to be brought up to standards. The municipality of Wentworth-Nord and the regional county municipality of the Pays-en-Haut, which has engineering studies on the state of the dam, were also indicated in the data sheet of the Repertoire of the dams of the MELCC as being its owners or agents. Lake St. François-Xavier ; PAFMAN

"The PAFMAN unfolds in two parts:
Part 1: A study of security assessment of the municipal dam in accordance with the obligations laid down by the law on the safety of dams;
Part 2: Execution of repairs arising from the recommendations of the evaluation study on the security of each dam and which are required to ensure its security and its compliance with standards in accordance with the law."

January 29, 2019, a release of the MELCC, now under the authority of the Minister Benoit Charrette, announced that eligible municipalities could now benefit from the program. MELCC, communiqué

PS. Would it not be normal, in the presence of any dam in inhabited areas, to assess the risk of flooding below in case of a dam burst? Urgence Québec gives some measures to be taken in front of such a risk. In the case of Lake St. François-Xavier and according to the form that would take such a burst, we can well imagine that the flow would instantly take the direction of Deer Lake and its shoreline, 40 meters below and only 600 meters from the dam. This short route is also enough incised to form a channel for water, mud and debris of all kinds. Today, simulation software use topographic and hydrological data, among others, to allow specialists to visualize the effect of such an eventuality. Risk level, Portrait de la ZGIE, Abrinord, pages 140 to 143 ; Loi sur la sécurité des barrages

With the use of Microsoft Translator and Linguee

By Carl Chapdelaine

Topographic profile of the Newaygo Basin

The Lakes of the Canadian Shield were still occupied by glaciers 10,000 years ago. Sliding slowly upstream downstream in the valleys, the latter have overdeepened closed depressions by abrasion, often giving these glacier lakes their typical U or pot shape. Here, the North-South profile crosses two depressions: the Lake and the adjoining Bay. By combining theory to bathymetric or isobaths curves, one can imagine their own profile. The isobaths are themselves extrapolations from spot measures. The Google Earth elevation profile would be, on the other hand, in full from the satellite photo obtained.

With Microsoft Translator + Linguee
View a path’s elevation profile on Google Earth Pro
Carl Chapdelaine

Grade: % and degree

On Google Earth, by moving the arrow along the profile of the chart, you will get a reading of the elevation at this new point, of the distance between the point of origin of the profile and this point, and the percentage of grade at the latter. The inclination of the slope seen on the chart does not represent the actual inclination; it is simply the result of the ratio between the vertical axis, here the altitude, and the horizontal axis, here the length on the field of the profile. The slope percentage, however, is real. A grade of 100% corresponds to an inclination of 45 ° (degrees). It is given a positive or negative value to differentiate the two directions. A grade of 40.2%, as on this graph is equal to 22 °. It is this last measure you would visually see on the ground. Looking at the Laurel-Montfort topographic profile, one would see the Rocky Mountains rather than the Laurentians...  Wikipedia         

Please report any mistake or misleading translation that you would have noted.                                                                                     C.C.                             

topographic profile of the Montfort Basin

Here the profile crosses both the summit of Mount Napoleon and the pit of the East Basin.  
Topography and altitude are specific to the Google Earth methodology. Approximate bathymetry based on interpretation of the CRE-Laurentides map.

 Bathymetric map, East                     C.C.

Map of the region, 1894

This inset map is from a larger one that covers a large area north of Montreal and part of the Outaouais Region. The link allows you to access the entire map scanned by the Direction de la Collection nationale et des collections patrimoniales, from the  Bibliothèque et Archives nationales du Québec.
Roads, from which the roads of today have used some sections, are plotted in red. The train would have come to Montfort in 1894, the year of publication of the map; however, the railway which was a branch line from the «P’tit train du Nord»’s main has not yet been sketched. The latter had joined Chute aux Iroquois (Labelle) in December 1893.
The map also shows the division of the territory into townships, ranks (Roman numerals) and lots. Wentworth-Nord did not exist yet; Montfort was in the large Township of Wentworth.
The detail does not allow us to precisely appreciate the outline of Lake Saint-François-Xavier.  Following the construction of a first dam by the brothers to run the orphanage sawmill, had it already overflowed its original bed? It is unlikely. Is then the 1894 map giving us the contour of the original lake?  In the inventory of the MDDELCC’s Centre d’expertise hydrique, the dam is said having been built in 1900 and modified in 1920.
Also, why can the two meters level of depth of the bathymetric map let us believe that there were originally two lakes, while literature always makes mention of one lake from the start? Would the ballast probably used for the construction of the railway have divided the Lake into two basins?

Note: We should soon have, for the first time, another map being scanned, dating from 1897 and showing the major Lakes of the region North of Montreal accessible by the Canadian Pacific railway or that of the Montfort Rail Road.
Carl Chapdelaine
Collections nationale et patrimoniales, BAnQ

Density of the habitat 

It would be interesting to have a figure of the density of the habitat around Lake St-François-Xavier, in its various facets.  Without it, how could we possibly define the support capacity of the Lake, i.e. what degree of impact of human activities on its border it can absorb, without having its natural balance disrupted?
There is the road network; its maintenance and traffic that it supports that threaten it greatly. There is the input of wastewater, the flow of motorized boats, etc. And all of these factors are more or less substantial depending, somehow, on their frequency. They are indeed based on the seasons, the length of stay of residents and visitors, yearly, seasonal or occasional. But data are too scarce at the Lake to measure the weight of each of these variables.
Here, using the houses localization by determined sector around the Lake and the ratio of their number in a half square kilometre1, one can have a quick overview of the diversity in the density of habitat in these same areas. It's a bit like making an inventory of the periphyton after having divided the Lake in a certain number of sectors, or the characterization of the shore.
We could also assume that seasonal cottages are occupied for less than 100 days per year on average; that is certainly the case for those who are not winterized. The traffic generated by the cottagers frequenting them follows the same curve. With an average of two people per household in Wentworth-Nord, we could estimate the number of residents who live in the various sectors identified in the Lake by counting the number of houses. The resulting figure could be compared with the data on residents possibly already available at the Municipality and adjusted. But only a survey on their length of stay and that of their visitors would allow us to associate to it the density on a day to day basis of this habitat or, let’s say, its actual frequentation.
Our cartographic approach does not claim to be scientific; we would need to push more deeply in details and calculations in order that it slightly is. However, if our glance can already give us a good idea of our environment, we can expect at least an overview of the situation. It would be interesting, following a more rigorous analysis, to see if there is a correlation between the degree of vulnerability of a specific sector and the density of its habitat, once weighted any other variable involved.
1. In order to respect the ratio, the number of houses is multiplied by two for the areas of 1/8 of 1 km2 (125 000 m2).

The sawmill duct


Lake St. François-Xavier's dam

September 6, 2015
 In the inventory of the MDDELCC’s (Quebec’s Department of Environment) Centre d’expertise hydrique, the X0005087 dam, built in 1900 and modified in 1920, is said to be of "high-capacity" since, among other things, it has a holding capacity of more than 1 million m3.*  And it has just been reclassified on the rise, as a "B", following, for one, the visit of Mr. Éric Martel, representative of the Centre d’expertise, could we learn from the MRC’s recent release.  It has a height of 2.4 m, a length of 103 m;  and it is said to be an "earthen dam".  However, there is no information about its strength; and the level of consequences of its failure is unknown.  It was not the first dam built at the foot of the lake; a previous one must have been dating from the 1880s, at the beginning of the founding of Montfort.  
Engineer Pierre Dumas showed us a cropping of the original bathymetric maps of Dr. Richard Carignan. (They are in possession of the municipal authorities). By following the 2 meters isobath, they show us the Western and Eastern sections of the lake with their corresponding lowered water levels; it must have been the height and initial rough outline of the Lake, before the construction of a dam. Both basins would have then been forming two separate lakes.  You could look at their two hypsometric sheets in the Laurentians lakes web Atlas and see what area and what volume of water that represents. Other data, such as time of renewal and drainage ratio, are also evaluated, Atlas des lacs : Lake St. François-Xavier (West)Atlas des lacs: Lake St. François-Xavier (East). (When following the 2m isobath, looking at the global bathymetric map gives an idea of the former lake contour : Bathymetric map of LSFX)
 In its 1941 report, the Commission of Common Waters of Quebec mentions the existence of two concrete dam sections, a first one of 29 feet. (It was at the entrance of the road access leading to the Montfort Pavilion, where the observation trench has just been dug and where is the fire water intake; but where you will not see much visible traces of still present concrete parts. According to the report, the dam had a hole to let the water pass to a wooden supply line (girdled with iron); its diameter is not specified.
 (Our hypothesis is that the original duct was at least of four feet in diameter. The dam was demolished and replaced by the current dike. A huge funnel, possibly in metal, would eventually be incorporated into the structure to direct water towards the duct, while the wooden one was replaced by a metallic, of only two feet in diameter The latter proved to be insufficient to supply the saw mill and the power plant situated below, without forgetting, at a time, the wooden pool for the orphans. A large diesel Chrysler engine had to be added, as well as a huge reservoir for this hydrocarbon that has had the misfortune to flow into Deer Lake to kill quantity of fish.)
 This duct appears to have been in a straight line, from the opening in the dam to the last concrete pillar.  It borrowed a depression in the land while leaving the dam, at the crossing of route Principale and the access road to the Pavilion, where it passed under a bridge.  A long series of these supporting pillars, spaced by ten feet, are always present at the entrance of the village and join the Main road at Hydro Quebec’s post 14-42. But they are almost completely hidden by shrub lands.  Strangely enough, these pillars are sometimes of arch opening for receiving an about two feet in diameter duct, while others, interspersed in the alignment, are rather designed to receive one of at least four feet; i.e. probably for the earlier wooden conduct but as well used to support the new one.
 The second section of concrete was a 70-foot dam (probably the one blocking the current channel that opens next to the Pavilion), pierced with two openings for overflow, a bottom valve and a wooden sluice 8 feet wide (Is it a door that can be used to remove water during floods?). It was probably the section that was demolished to be replaced by culverts under the Chemin de Lisbourg and on which the boys liked to show fearlessness.
 As we were told by Mr. Mayor Genest, water leaks appeared in downstream of the structure in recent years. On dry weather indeed, several small water leaks are now visible in the observation trench dug for this purpose. The MRC has recently hired Mr. Pierre Dumas, an engineer and consultant in hydraulics, energy and environment, expert in dammed lakes, to conduct a safety study on the century-old dam. We saw the engineer at work on earth and, using a tuba, in the lake, not far from where the fire water intake is located.
 No tree planting should have dressed this structure had already learned Mayor Genest; with decomposition, tree roots, which have drilled deep paths, will eventually leave as many inappropriate channels to pressurized water.  He had also let know that an engineering firm, briefly consulted, was already suggesting a widening of the dam where are the seen leaks, while a second, specialized in dams, would have gone for digging there a trench to be filled with clay.
The rupture of a lake or river dam may occur, as was the case with the artificial Lake Bison (600 meters long) at Saint-Raymond, in Portneuf, which emptied in about five minutes in June, after having yet undergone the prescribed inspections successfully.  Some local residents reported having experience a mini tsunami and believe that water infiltration in the dam could be the cause, while heavy rainfalls had completed the work. The unlikely failure of the dam of Lake Saint-François-Xavier would be of a different order of magnitude; mais dont le Québec a eu de tristes exemples. but Quebec has known sad examples of such.
A first dam and duct were therefore built at Lake St. François-Xavier from the beginning of colonization;  it was essential to the operation of a sawmill that would allow the construction of the village and the orphanage.  That probably was the dam that would have collapsed, as reported by the elders, taking away all the facilities of the mill it served at the time; mais apparemment sans faire de victime. but apparently causing no casualties.
 Thank you to Mr. Gérard Chartier for his valuable collaboration.
 Information and old photos from residents to shed light on the overall picture of this issue would be most appreciated.

 Carl Chapdelaine


observation trench

Former Lake (West)

Former Lake (East)

Oh Lake!

With the best wishes for the Christmas Holidays from the RSVL team.


Alphonse Beauregard (1881-1924)

At the feet of three hills dressed with firs lies a deep, clear and wise lake, where many times I got off, in the morning, to pick up the peace it offers.

Round and lush, at its centre, an island looks like the diamond of a ring. Around, leaning trees, at the water's edge, draw there vague shapes.

Still free of any dock, of any open path; useless and pure tiara; it is in the harshness of this desert country, a work of art to the art itself.

I'm your poor lover, Lake; but can't stop sinister axes. Hear their sound around, the bell tools of the trees which dress-up and hide you.

You will become, among houses and bare fields, water without attractions, a pool, a thing which is used to navigate over, grabbed by masses.

Who cares! They will not, these imposed masters, have known your smile of virgin; I keep it in my heart like a secret kiss that I would have picked on your bank.


Lake St. Francois Xavier

Topographic map of the lake

«Toporama» is a service of the Atlas of Canada. The arrow turns into cross to go in all directions, covering all of Canada. The search tool takes you directly to the desired location (but you will have to find your way back…).
The map can be enlarged to full page using the link at the bottom, to the left of the latter; you then discover new interesting strong tools. One of them allows you to measure the distance between two points that you have placed anywhere on the map, or to get the area of a polygon that you have managed to draw around a lake, for example.
Click on the small image, here on the right, to see how I got 0.7 square km for Lake Saint-François-Xavier, by drawing its outline, in fact, by a succession of straight segments forming the sought polygon (blue line). 
As a first step, once the map is zoomed in, you "put under the magnifying glass" i.e. maximize what you want to measure; it will be more accurate. You click on "To measure". The icon of the tool for measuring a surface appears darker; then you point the arrow on your starting point and click left once. You move the line to the first change in direction, then release. You click left once again; and so on until you have closed the polygon. You then double-click, always left, and look at the result. Don't worry about the other side of the polygon that follows your every movement. But don't do anything else at the same time; you could ruin your effort...
If you find more interesting options, let us know. 

Enlarge map


Bathymetric maps

Bathymetric Map (West)                          Bathymetric map (East)

Lake St. Francois Xavier watershed

A first publication of such a map, thanks to Abrinord.
Lake Saint-François-Xavier watershed is a sub-basin of the Rivière-à-Simon’s one. This watershed is itself included in the Rivière du Nord watershed, which with that of the Rivière Rouge cover a large part of our region before both flowing into the Ottawa River. The bold black line on this map delineates this whole from the Rivière rouge watershed, at West and South here, with Notre-Dame and Saint-Victor Lakes left blank. Our thanks to Abrinord, the Rivière du Nord watershed organization, involved in several research projects carried out by the MRC or other and with which we look forward to collaboration in certain issues.


Rivière-à-Simon's watershed

Here, at a smaller scale, is the Rivière-à-Simon watershed in which are included Lake St. François-Xavier and Deer Lake. 
You will find our lake at the southwestern end, just over the word Wentworth-Nord, since the limit separating us from Rivière Rouge watershed goes between our lake and the Lake St. Victor - Lake Notre-Dame duo.
You will notice that we are at the head of our part of the watershed, only topped by small Lac-à-la-Croix. We may be a risk for others, namely Lake Chevreuil, but no one is a risk to us.
Now, isn’t that amazing to see the area covered by the Rivière-à-Simon watershed?

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