Understanding Lake Nipissing And French River Water Levels
Managing the Lake Nipissing / French River watershed is difficult. Prior to the construction of the Chaudiere control dams at Dokis, the water level of Lake Nipissing was actually lower than at present and was subject to extreme fluctuations. Despite being shallow, Lake Nipissing does hold a vast amount of water, and downstream on the Lower French, sudden rises or drops in water level can cause havoc. The mind-set of those managing the water levels is that we must “share the pain”, and that sometimes we might be inconvenienced by higher or lower than average water levels. The Operating Guideline signed in 1995 by all stakeholders stipulate that at least a minimum flow must be maintained even in dry times. In the dry summer of 2010, Lake Nipissing was about 60 cm (2 feet) below the summer average, and that was definitely an inconvenience. The Lower French was 2 m (6 feet) lower than average, causing even greater difficulty.
The Canada Public Works web site http://www.tpsgc-pwgsc.gc.ca/ontario/eaux-water/renseignement-information-eng.html
provides information that is updated Monday of every week. Note the reference to the “long-term average”. This means the average for the present date, similar to the concept of the “average temperature” given in weather forecasts.
The goal for the summer is a 20 cm (8 inch) operating range
from 195.75 metres above sea level (masl) to 195.95 masl. (The goal for the winter draw-down is 194.5 masl.)
Another website gives continual data from recorders on Lake Nipissing and the French River and hundreds of other stations across Ontario and Canada.
Lake Nipissing (Government Dock at North Bay):
At the French River outlet (Chaudiere Dam):
The graph uses a base line of 190 m. Thus “5.25” on the vertical axis means 195.25 metres above sea level.
You can search for the water level of other rivers and lakes at http://www.wateroffice.ec.gc.ca/text_search/search_e.html?search_by=p®ion=ON
In the fall, usually beginning at the end of October, the lake is drawn down slowly to its winter level 194.5 masl. This level is reached in late winter before the spring freshet.
INTERVIEW WITH PHIL HALL - MNR Nov. 11, 2010
In the October newsletter, I briefly described the meeting at Sturgeon Falls on October 19 regarding the economic impact of low water in Lake Nipissing. Putting everything in perspective, and despite the many inconveniences presented by the past summer, the record shows that the system is working fairly well despite the many challenges faced.
The following two charts show the planned and actual water levels during 2010. Click to enlarge.
January to June, 2010
July to December (2010)
These graphs are confusing to say the least as there is a lot of extra data portrayed at once (like precipitation at the top). Note that the left side vertical axis is for Lake Nipissing, while the right side vertical axis is for Dry Pine Bay on the Lower French.
Look for the two very straight lines
, parallel during the summer and converging downward after late September; these lines represent the target operating range for Lake Nipissing. The heaviest bold line mid-graph is the Lake Nipissing level, while the line at the bottom is the level of the Lower French
The following is presented in an interview format to show the answers to questions presented to Phil Hall, Land and Water Specialist at the North Bay MNR, after the October 19 meeting in Sturgeon Falls.
Dave Minden: (At the Sturgeon Falls meeting) you referred to the minimum outflows at the Chaudiere and Portage Dams that were set in May. At the Portage Dam, you said one gate was open 5”, another 2”; and the Big Chaudiere was open 5”. So when other dams in the area were shut tight, there was, therefore, very little water coming in but a significant amount still going out. Why was this practice not modified when it became evident there was a problem? Would the natural Free Flowing Channel not have served the purpose of providing some water to the river below the dams?
Phil Hall: The minimum outflow of 35 cubic metres per second was established after much negotiation between 1992 and 1995 following the flooding in Field (on the Sturgeon River) in 1979. This is the lowest possible outflow allowed under the Operating Guideline, and to alter it would require very extensive re-negotiations with all parties, especially those on the Lower French. While those on Lake Nipissing were quite affected, some, like marine owner Mike Palmer on the Lower French, could not put his barge in all summer. It’s worthy to note that the target summer operating range on Lake Nipissing is between 195.95 metres above sea level (masl) and 195.75 masl, a range of 20 cm (8 inches). But on the Lower French, they regularly deal with a fluctuation from a high point of 182.0 masl to 180.43 masl, a range of 1.6 m, or over 5 feet. On November 1, they were still 96 cm below the long-term average, while Lake Nipissing has climbed back to just 17 cm below average for this date.
The water was low in a very wide geographic area, due to practically zero precipitation in March (when we normally receive huge amounts of snow and rain) and then a very dry spring and summer. Lady Evelyn Lake (north of Temagami) was about 5 feet low; Rabbit Lake was 3 feet low. West of Thunder Bay, Kakabeka Falls and the Magpie River were dry. In Quebec, the head-waters of many major rivers were very low, and docks were high and dry on Lake Temiskaming and the Ottawa River.
Dave: When it did rain, we saw the water level come up a bit. Then a day later it dropped to a level even lower than it was before it had rained. We observed and photographed this on several occasions (rare as they were). What was going on that caused this?
Phil: This is hard to explain. We saw that there was virtually no run-off from the scant rainfall that occurred during the summer months. It took until mid-September for some substantial rain to begin to make it to Lake Nipissing and the levels started to rise. Probably the ground was so dry that it took a while for the system to re-charge.
Dave: Can the draw-down be postponed to later in the winter (like in February) when the snow-pack and water content are known, not just predicted?
Phil: No, partly due to the operational problem that the gates are frozen in place. While the level is still presently below the long term average, it is climbing and is presently 17 cm below the long term average for this date (Nov. 1); the draw-down would have started in early October, but will not occur until the level gets back into the target range, which could occur mid-November. The water has to be drawn down very carefully to avoid a huge surge further down-river, and is controlled at a rate of an additional 25 to 30 cubic metres per second, which translates into an increase of about 12-15 cm downstream. The target draw-down level is 194.5 masl which is attained in January. During the winter, the committee meets to discuss snow depth, water content of the snow, and to plan for the spring freshet and spawning seasons.
Dave: Could you reiterate your summary of the last dozen or so years, when you referred to the number of years the lake was within the target range, above, below, etc. These statistics put things in perspective. You mentioned that last year, “there were no complaints” when it rained a lot and the water level was quite high. Does this suggest there might be a preference for and an acceptability of a higher level than what is presently aimed for. (I, for one, would prefer a generally higher level overall.)
Phil: In most years, we did achieve the target range. In 1998 and especially 1999, the water was low, but it did recover in the summer of ‘99. The operational range for the navigation season is 195.75 metres above sea level to 195.95 masl. The figures cited below are for June 1 of that year to provide a consistent base line.
1992 In range
1993 In range
1994 In range
1995 In range
1996 In range
1997 High by 15 cm; 122% of normal precipitation in May
1998 Low by 15 cm; 40% of normal precipitation in May
1999 Low - 60 cm below long term average in June; 10 cm below in July
2000 In range
2001 High by 15 cm on June 1. High water in the fall by 40 cm (end of October).
2002 In range
2003 In range
2004 High by 20 cm; 183% of normal precipitation in May
2005 Low by 25 cm; 30% of normal precipitation in May
2006 In range
2007 In range
2008 In range
2009 In range - it was near the top of the operating range but only above it in early summer
2010 Very low (as we know) Low by 60 cm and never recovered in the navigation season.
2011 ? Not predicting a repeat! (The lake was quite high after heavy June rainfall; the level dropped through the summer as there was very little rain in July and August.)
The level of Lake Nipissing on Nov. 09, 2010 was 195.48 masl. The draw down which would have started at the beginning of October has been delayed and will not occur until the level reaches the target range or draw down level – the downward sloping straight lines on the graph. While the present level is higher than it has been all summer, it is still about 17 cm below the long term average for this date. It is still about 27 cm (just under 1 foot) below the bottom of the summer operating range.
Source: Dave Minden