August 12, 2023 ...read the report
Since my last report on July 23, the water level of Grand Lac Rond has increased by 7 cm to 147.28 m. The lake water level has been very stable lately and it is at a very healthy water level. The reasons for the stability are mainly due to heavy precipitation and constant discharge from the dam at Lac des 31 Milles.
When comparing the water level of Grand Lac Rond to previous years during the same period, it is located in the highest water levels:
August 12, 2023 - 147.28 m
August 10, 2022 - 147.15m
August 15, 2021 - 147.10 m
August 09, 2020 - 147.23 m
August 11, 2019 - 147.05 m
August 14, 2018 - 147.21 m
August 14, 2017 - 147.13 m
August 10, 2016 - 147.03 m
August 15, 2015 - 147.16 m
July 22, 2023...read the report
Since my last report on July 10, the water level of Grand Lac Rond has decreased only 2 cm to 147.21 m. In other words, the water level of the lake is stable and at a healthy level. (I consider that a level between 147.10 and 147.30 m is good for the lake.) The reasons for the stability of the water level of the lake are mainly that there has been a continual flow from the Lac des 31 Miles (it's been down 4cm since July 10) and that there has been good rain recently.
When we compare the water level of Grand Lac Rond to previous years during the same period, it is about average:
July 22, 2023 - 147.21 m
July 15, 2022 - 147.21 m
July 24, 2021 - 147.33 m
July 21, 2020 - 146.99m
July 22, 2019 - 147.39 m
July 20, 2018 - 147.09 m
July 22, 2017 - 147.48m
July 24, 2018 - 147.06 m
July 20, 2017 - 147.03 m
July 25, 2016 - 147.03 m
July 21, 2015 - 147.24m
July 10, 2023...read the report
Since last week, the water level of Grand Lac Rond has increased by 20 cm (8 inches)! As there was little precipitation during this period, the reason for this increase seems to be entirely due to the flow of the Lac des 31 Milles dam. The water level at Lac des 31 Milles decreased by 3 cm from 162.23 to 162.20 m, which is slightly higher than its normal water level for the summer.
The water level of Grand Lac Rond is currently at a very healthy level, although it is slightly lower than the levels of the same period in previous years.
July 10, 2023 - 147.23 m
July 13, 2022 - 147.23 m
July 10, 2021 - 147.35m
July 10, 2020 - 146.95m
July 14, 2019 - 147.35m
July 10, 2018 - 147.33 m
July 10, 2017 - 147.64 m
July 10, 2016 - 146.97 m
July 11, 2015 - 147.02 m
July 11, 2014 - 147.14 m
July 08, 2013 - 147.54 m
I would like to mention that at the annual meeting of the Association du Grand Lac Rond yesterday, there was a great deal of interest in discussing the issue of the lake's water level. Many people expressed the feeling that unstable water levels are problematic and were interested in finding solutions.
June 30, 2023...read the report
Here is my update of the water level report for Grand Lac Rond. Since my last report on June 25, the water level has increased by 5 cm to 147.03 m. But the water level of the lake is still low. A water level between 147.10 and 147.30 will be healthy for the lake.
The main reason for the increase in the water level of Grand Lac Rond is due to a fairly abundant and much needed precipitation (41.5 mm). Upstream at Lac des 31 Milles, the water level increased by 6 cm and remained at 162.23 m from June 28 until today. This is at least 8 cm higher than the normal summer level maintained for this lake. As I mentioned in my last report, Grand Lac Rond has experienced drought conditions recently while Lac des 31 Milles has experienced above normal conditions. It is puzzling that two lakes in the same watershed have such differences. The amount of water entering Grand Lac Rond is not equal to the water leaving it, raising questions about the controlled flow of the Hubert Tremblay Dam spill as well as the uncontrolled flow of the Grand Lac Circle in the Gatineau River. A hydrometric station on Grand Lac Rond would be an important step for the CEHQ to understand the effect of the dam on the lake.
When we compare the water level of Grand Lac Rond with the same period of the past years, it is low:
June 30, 2023 - 147.03 m
June 25, 2022 - 147.69 m
July 1, 2021 - 147.18 m
June 25, 2020 - 147.05 m
July 2, 2019 - 147.54 m
July 6, 2018 - 147.37 m
June 22, 2017 - 147.60m
June 30, 2016 - 146.97m
June 25, 2015 - 147.14 m
June 30, 2014 - 147.19m
June 30, 2013 - 147.44 m
June 25, 2023 ....read more
Since my last report last week, the water level of Grand Lac Rond has continued to decrease. When I took my measurement on June 25 it was 146.98m, which is 6cm lower.
The water level was already very low the last time I measured it, but now it is in a critical state which is not good for the environment and besides other problems it can lead to the formation of blue algae in hot water. Yes, I took this measurement before the rains started and I hope the water level will rise again to healthy levels. However, this kind of fluctuation is not good for the environment and I believe it can be avoided. It is disheartening that the CEHQ does not have the capacity to know the effect on the water level of Grand Lac Rond when it retains or releases water from the dam. A hydrometric station on the Grand Lac Rond would be a step to correct this oversight.
Since June 4, the water level of Grand Lac Rond has dropped by 25 cm while that of Lac des 31 Milles has dropped by 3 cm. As there was little precipitation during this period, the water leaving Grand Lac Rond was not replaced by the water discharged upstream. Consequently, the discharge rate of 2.8 m3/s from the dam at Lac des 31 Milles does not seem sufficient to maintain a minimum water level for Grand Lac Rond. Also, it is disturbing to see two lakes in one watershed where one is experiencing drought conditions and the other is experiencing slightly above normal conditions. There should be an explanation why this is happening.
When we compare the water level of Grand Lac Rond with the same period of the past years, it is low:
June 25, 2023 - 146.98 m
June 25, 2022 - 147.69 m
June 24, 2021 - 146.98 m
June 25, 2020 - 147.05 m
June 24, 2019 - 147.56 m
June 19, 2018 - 147.52m
June 22, 2017 - 147.34 m
June 25, 2016 - 147.03 m
June 25, 2015 - 147.14 m
June 24, 2014 - 147.19 m
June 30, 2013 - 147.44 m
June 17, 2023 - read more...
Since last week, the water level of Grand Lac Rond has dropped by 6 cm to 147.04 m. The water level of the lake is very low for this time of year:
June 17, 2023 - 147.04 m
June 06, 2022 - 147.79 m
June 17, 2021 - 146.98 m
June 17, 2020 - 147.26 m
June 15, 2019 - 147.46 m
June 16, 2018 - 147.47m
June 18, 2017 - 147.34 m
June 18, 2016 - 147.11 m
June 15, 2015 - 147.19 m
June 17, 2014 - 147.31 m
On the other hand, the water level of Lac des 31 Milles is slightly higher than its normal summer levels. This may be due to the reserve he held in May to prevent catastrophic flooding on Grand Lac Rond. However, it is hoped that both lakes will reflect the same situation in the watershed as the summer progresses.
June 16, 2023
Here is my update of the water level of Grand Lac Rond.
Since last week the water level of Grand Lac Rond has decreased by 13 cm (5 inches) to 147.10 m. If you recall last week the water level dropped 16cm, so the lake is currently going through a period of active instability.
When we compare the water level of Grand Lac Rond with the same period in past years, it is low:
June 11, 2023 - 147.10 m
June 6, 2022 - 147.79 m (the year of heavy flooding)
June 12, 2021 - 147.00 m
June 11, 2020 - 147.39 m
June 13, 2019 - 147.49 m (the year of heavy flooding)
June 7, 2018 - 147.36 m
June 12, 2017 - 147.57 m (the year of heavy flooding)
June 11, 2016 - 147.24 m
June 11, 2015 - 147.21 m
June 8, 2014 - 147.26 m
June 8, 2013 - 147.51 m
Good week,
Michael
June 3, 2023
Here is my update of the water level of Grand Lac Rond.
Today the water level is at 147.23 m, which is 16 cm lower than last week. (Since yesterday the water level has dropped by 3 cm, which is quite fast.)
The reasons for the changes are due to the lack of precipitation and the water level of the Gatineau River which has dropped by 90 cm (from 163.85 m to 162.95 m) which increases the water discharge from Grand Lac Rond. . At Lac des 31 Milles, the water level gradually dropped by 4 cm (from 162.24 to 162.20 m).
When we compare the water level of Grand Lac Rond with the same period of the past years, it is within the norms or perhaps slightly low:
June 4, 2023 - 147.23 m
June 6, 2022 - 147.79 m (the year of heavy flooding)
June 1, 2021 - 147.05 m
June 9, 2020 - 147.44 m
June 4, 2019 - 148.34 m (the year of heavy flooding)
June 3, 2018 - 147.29 m
June 9, 2017 - 147.68 m (the year of heavy flooding)
June 11, 2016 - 147.24 m
June 6, 2015 - 147.29 m
June 6, 2014 - 147.30 m
June 8, 2013 - 147.51 m
May 8, 2023
The water level of Grand Lac Rond is still flooded. It is now at 147.81m, which is 5cm higher than last week. During the weekend it remained stable but very flooded.
The Gatineau River has remained high at 165.15 m since May 1. When the river is high, it prevents water from flowing out of Grand Lac Rond, which increases the water level at the lake.
Lac des 31 Milles has risen 6 cm to 162.26 m since May 1. When the water level of this lake rises, it generally discharges less water downstream, which prevents the water level of Grand Lac Rond from rising.
The following is a comparison of water levels on Grand Lac Rond for periods when it was severely flooded:
May 8, 2023 - 147.81m
May 7, 2022 - 147.81 m
May 8, 2019 - 148.24m
May 9, 2018 - 147.92m
May 9, 2017 - 148.69m
May 8, 2016 - 147.87m
So although the Grand Lac Rond is not at the same level as the floods of 2017 and 2019, it is at a water level comparable to that of last year when the lake was heavily flooded for 3 months (April 9 to June 25, 2022). This is why it is essential that the Lac des 31 Milles keep a good reserve for the next period until the Gatineau River drops, otherwise the Grand Lac Rond will be severely flooded like last year.
May 5, 2023
The Grand Lac Rond is still flooded. Since last week, the water level has increased by 9 cm (3.5 inches) to 147.85 m.
I thought it would have been worse with all the precipitation for the week and with the rise of the Gatineau River (which slows the exit of water from the lake and therefore raises the water level of Grand Lac Rond). Fortunately, the water level of Lac des 31 Milles has risen by 10 cm to 162.25 m (which slows down the discharge of water downstream and prevents the water level of Grand Lac Rond from rising even higher).
I believe that in the next few days the Lac des 31 Milles will have to continue to keep a significant water reserve, otherwise the already bad situation on the Grand Lac Rond could become catastrophic.
May 2, 2023
Since my last report on April 21, the water level of Grand Lac Rond has decreased by 22 cm (8.5 inches) to 147.76 m, on Saturday April 29 - before the precipitation.
The problem is that the situation can change quickly on the lake.
On Saturday, the Gatineau River was still very high. The hydrometric station in Maniwaki was at 165.05 m on Saturday and today it rose another 10 cm. When the river is high, it prevents the water from coming out of the Grand Lac Rond.
On Saturday, the water level of Lac des 31 Milles was stable at 162.14 m (which means that there was a discharge downstream). Today, the level rose 7 cm to 162.21 m (which means - perhaps - that the discharge has decreased). Please note that on May 4, 2019, the water level of Lac des 31 Milles was authorized to rise to 162.60 m in order to prevent flooding at Grand Lac Rond.
And, since Saturday, the area has had 44.5mm of precipitation (meaning water levels have risen due to runoff in the watershed).
So, it's just to say that the situation on the lake can change drastically from day to day. If you remember last year the water level dropped 52cm from April 22nd to May 7th and then rose 128cm by May 28th! Unfortunately, I can't measure the water level until next weekend (which is another illustration of why Grand Lac Rond needs a permanent hydrometric station to alert residents and the CEHQ of dramatic changes).
April 21, 2023
Since Wednesday, the water level of Grand Lac Rond has decreased by 4 cm (1.5 inches) to 147.98 m. It goes without saying that the water level is still extremely high for this time of year. As I explained on Wednesday, April 18, 2021, its water level was 147.21 m - 77 cm (30.5 inches) lower than today!
As for the Gatineau River, from April 14 to 19, it rose 82 cm (32 inches) at the hydrometric station in Maniwaki (164.84 m). This has the effect of slowing down the water flow of Grand Lac Rond and therefore raising its water level. Fortunately, today the river level dropped slightly by 3 cm (1 inch). It is hoped that this trend will continue since it will reduce the flooding of Grand Lac Rond.
As for Lac des 31 Milles, the water level continues to rise but at a much slower pace. I don't know the reason for this. The level of Lac des 31 Milles is now at 162.09 m - 6 cm less than its normal water level in summer. As I explained on Wednesday, the Lac des 31 Milles dam has the capacity to create a much higher reserve. (On May 4, 2019, the water level of Lac des 31 Milles rose to 162.60 m.) On page 12 of my report A decade of measuring water levels at Grand Lac Rond (Lac Roddick) 2010 - 2022, I demonstrated that:
if the water level of Lac des 31 Milles can be held back by 20 cm (8 inches), this can save Grand Lac Rond an additional 59 cm (23 inches) of flooding!
These repercussions on Lac des 31 Milles would be quite minor but would have a significant effect on Grand Lac Rond.
The weather forecast for this weekend calls for rain. If the river level continues to decrease and if the water level of Lac des 31 Milles can rise more quickly, perhaps Grand Lac Rond will be spared further flooding.
April 18, 2023
Grand Lac Rond is already flooded. Its water level is 148.02 m.
By comparison, on April 18, 2021, its water level was 147.21 m - 81 cm (32 inches) lower than today!
In 2019 and 2022 when the lake was heavily flooded, the water level was 148.20 m (April 25, 2019) and 147.99 m (April 22, 2022).
The forecast is not good.
The water level of the Gatineau River is very high, which has the effect of preventing water from leaving Grand Lac Rond and consequently its water level rises.
The water level of the Lac des 31 Milles is increasing, which has the effect of slowing down the entry of water into the Grand Lac Rond. Currently the water level of Lac des 31 Milles is at 162.07 m. It is hoped that its water level will continue to rise, otherwise there will be severe flooding downstream. (On May 4, 2019, the water level of Lac des 31 Milles rose to 162.60 m.)
Finally, the weather forecast announces up to 18 mm of precipitation this weekend.
Unfortunately I cannot make regular measurements of the water level on Grand Lac Rond despite the need to monitor it closely.