December 2021

I have archived the December 2021 Water Level Chart (at left), bringing 2021 to a close. Our general goal in December is to get the lake down to about 18 inches by the time it freezes over, without overshooting the mark. We have after all only 24 inches to play with. As it turns out, the lake froze over on December 20th with the lake level down just 1 foot. Precipitation for the month was 3.44 inches, average for December, bringing us to 46.18 inches for the year, 2.12 inches more than average. It is only because of the excessive rainfall we received in July (9 inches) and September (8.5 inches) that we ended the year a bit ahead of average precipitation because for most of the rest of the year, we fell short of monthly averages. And that’s about all I’m going to say about December. It’s a New Year.

One big difference between 2020 and 2021 turned out to be the flushing rates and retention times. In 2020 we had a flushing rate of about 2.3x with a retention time of 140 days. In 2021 the flushing rate was 1.8x (the same as the published rate for Clary Lake) with a retention time of 240 days. This is in effect a measure of the amount of water that passed through Clary Lake: in 2020, a total of 16,632 acre feet of water passed through the lake, in 2021 that figure was  significantly less, only 13,274 acre feet. The lower flushing rate in 2021 very likely had a beneficial effect on water quality.

[UPDATE]: I was so intrigued with the difference in flushing rate and retention time for 2020 and 2021 that I decided to graph them to make the differences more evident. Here’s the result:

I’ll add data for 2022 as it becomes available.

I can’t end 2021 without highlighting an interesting but ultimately useless bit of data analysis I wasted time on this year. Everyone knows that I love charts. If you don’t know that by now, then you simply haven’t been paying attention! I’d like to show you two fascinating but useless charts I made this year. First a bit of explanation. I have long thought it would be cool if I could somehow correlate the flows from Clary Lake with the flows in the Sheepscot River as measured at the Sheepscot River Gaging Station which is located at the foot of Grand Army Hill. It turns out you really can’t correlate the two flows in any reasonable fashion for two primary reasons. First, because the hydrological characteristics of the Clary Lake watershed (9.9 square miles) and that of the larger Sheepscot River watershed (142 square miles) are quite different. Clary should contribute 6.9% of the water measured at the gaging station but that figure actually varied from a low of around 1% to a high of 60% with an average of around 12.4%. Sheesh. Second, nobody actually controls the flows on the river, but we do in fact do control the outflows from Clary Lake so it is largely our own management activities that make correlating the two flows almost impossible. It would be nice if Clary outflows were always 6.9% of Sheepscot River flows, but I guess that would be too easy! Anyways, here are two charts I made while investigating whether a correlation between lake and river flows exists. One shows Clary Flows as a percentage of the Sheepscot River flows. The average turned out to be 12.43%. The other is a simple visual comparison of the two flow amounts which I did to see if anything jumped out at me. Nothing did:

Here’s the 2021 Water Level Chart gallery:

[Show slideshow]

Happy New Year everyone 🙂

Clary Lake has been trying to freeze over for about 3 weeks now, first at one end, then at the other. Each time it’s melted off. A good section out in front of my place has been ice free all along thanks to the ducks that come to our bird feeding station, they splash around and keep the ice from forming. Clary has just been waiting for a good cold night to freeze over, and last night was it. This morning the temperature was a paltry 9.9° F and from all appearances, the lake is now solidly frozen over. There is no sign of ducks today! Historically, A review of our Ice In and Ice Out Dates page shows that 12/20 is on the late side for the lake to freeze over. With the exception of the freak year in 2016 when the lake actually didn’t freeze over completely until January 15th, this is the latest ice-in date since the lake froze over on December 30, 2006. Continue reading →

November 2021

I have archived the November 2021 Water Level Chart (at left). The lake level in November was like a roller coaster ride. Our general plan for a dam operations in November is to get the lake level down a foot or so below the HWM in preparation for the lake freezing over sometime in December. A large rain event on the last day of October however brought the lake up to +0.25 ABOVE the high water mark, the highest the lake has been all year! On the first day of November we pulled one of the three remaining stop logs and opened the gate 1.05 feet to drain off some water which resulted in the lake level dropping 1.18 feet over over the next 12 days. Over the rest of the month we had numerous rain storms including one of 1.22 inches on the 12th and a 1.10 inch storm on the 22nd. This rainfall kept the lake level up higher than we would have liked. We ended the month with the lake level down 1.13 feet. Continue reading →

October 2021

I have archived the October 2021 Water Level Chart (at left). October was looking to be a very dry month with rainfall well below normal until the next to the last day of the month when a significant wind and rain storm blew through the area. I recorded 2.68 inches of rain by the time the weather cleared on the 31st, bringing our monthly total to 4.34 inches, just shy of the average for October of 4.45 inches. There was a major 3 day northeaster back on the 25th of the month that was forecast to drop 3-5 inches of rain here, but it turned out to be mostly a southern Maine rain event; here we received less than an inch of rain. I thought we’d end the month with the lake level down around 1 foot below the top of the dam, but instead, by the end of the day on the 31st the there was water running OVER the top of the dam, with the lake level the highest it’s been all year. This morning as I’m writing this, the lake level is 0.25 above the High Water Mark, and still rising. Continue reading →

June 2021

I have archived the June 2021 Water Level Chart (at left). The drought deepens. We were shy 5.20 inches of rainfall at the end of May, now we’re shy 6.76 inches of rainfall at  the end of June. We received a total of only 2.15 inches of rain in June, fully 1.58 inches less than normal. This brings us to 14.1 inches for the year to date. Our drought is nowhere near as severe as they’re experiencing in the western half of our country and especially in the southwest, but that is small consolation: this deficit will have a profound impact on our environment and ground water supplies for the rest of the year, and it’s not over. It’s so dry that even when we received a significant rainfall of 0.99 inches on the 22nd of June, the lake level only came up 1/3 of an inch. Lesser rainfall amounts during the month had almost no measurable effect on the lake level. There are two reasons for this: The primary explanation is that the ground around the lake is so dry that when the lake receives rain, the rising water is quickly wicked off into the surrounding dry shoreline. The other reason is that at this lake elevation, adding more water to the lake mostly makes the lake bigger, not deeper. Continue reading →

May 2021

I have archived the May 2021 Water Level Chart (at left). The dearth of precipitation which has plagued us all winter continued through the month of May. At the end of April we were 3.50 inches short of normal for the year and today, on the last day of May, having received an underwhelming 1.91 inches for the month (normal for May is 3.71 inches), we’re now worse off at 5.20 inches short of where we would be in a normal year. It would have been even worse but for the 0.93 inches of rain we received on Memorial Day, the last day of the month. The timing was lousy but the rain itself was very much needed and I’m glad we got it. It also seemed like a fitting end to a long cold weekend that had me burning wood in my stove again; I’m OK with putting on a sweater in the house but I draw the line at wearing gloves at dinner! The three day weekend also marked the start of our Courtesy Boat Inspection program and unsurprisingly, we didn’t inspect any boats entering or leaving the lake. It was not the 3 day weekend you were looking for! Continue reading →

April 2021

I have archived the April 2021 Water Level Chart (at left). The dearth of precipitation that has plagued us for much of last year and for the first three months of this year has continued into April with total monthly rainfall amounting to only 3.12 inches, a good deal of which we received on the last day of the month. This is well below the April average of 3.87 inches. Year to date we’re 3.5  inches below normal and we’re only a third of the way through the year. This does not bode well for ground water supplies this summer, even if precipitation returns to something like normal. The USDA has categorized this area of Maine as “Abnormally Dry” (see below) which is certainly an unusual condition for Springtime in the Northeast. Nationwide, drought conditions are much worse as this next graphic from the Maine Climate Office clearly shows: Continue reading →

March 2021

I have archived the March 2021 Water Level Chart (at left). Precipitation was again slow to accumulate in March and we ended the month with only 2.00 inches of rain, well below the monthly average of 3.77 inches. Despite the lack of snow pack and the lack of rain, we did succeed in filling the lake before the end of the month, and on pretty much the same date as last year. We did this by adding one or two stop logs, gradually raising the lake level (the black dashed line on the chart represents the height of stop logs in the weir). The dam’s gate was closed for the entire month and was only opened 1 foot on the 30th in anticipation of a significant rain event on expected on April 1st, no fooling! Filling the lake in the spring is made easier when there is more water to work with; we were able to do it this spring largely at the expense of meeting the minimum flow requirement. We started the month with the lake level down -1.15 feet below the HWM and ended up on March 31st with the lake at -0.20 feet below the HWM with a little water running over the dam. The ice went out on March 29th. Continue reading →

February 2021

I have archived the February 2021 Water Level Chart (at left). Precipitation was slow to accumulate this month but a rain/snow storm on the 27th finally pushed us to 2.67 inches for the month, just a hair above the February average of 2.61 inches. Year to date however we’re still the better part of an inch below normal and without any snow pack to speak of, we are looking at a drier than usual Spring. Most of Maine is not in drought this winter but there are some areas on the coast not far south from here that are considered “abnormally dry.” A lot can (and probably will) change between now and April. Continue reading →

January 2021

I have archived the January 2021 Water Level Chart (at left). The drought conditions that plagued us last year have returned early in 2021 with January’s precipitation of 2.16 inches falling considerably short of the normal monthly precipitation of 3.19 inches. February is the month with typically the lowest (2.61 inches) monthly precipitation of the year. We’re going to start February with a decent shot of snow in a couple of days. Hopefully we’ll develop a good snow pack by spring. Continue reading →

December 2020

And so we arrive at the end of another year. I have archived the December 2020 Water Level Chart (at left) and much like 2020 was a roller coaster year, December was a roller coaster month in terms of rainfall and resulting water level fluctuations! On the last day of November we received 1.75 inches of rain followed by 0.76 inches more the next day. This pushed the lake level from 0.68 feet below the HWM to 0.07 feet above the HWM almost overnight, resulting in water flowing over the top of the dam for the first time since last spring. Then on December 5th we received 2.00 inches of rain which drove the lake level even higher, to 0.18 feet above the HWM, despite our efforts to mitigate the lake level rise. From there the lake fell more or less steadily to the month low of 1.34 feet below the HWM. More rain on the 23rd and 25th of the month again pushed the lake level up to a little less than 1 foot below the HWM. It would have gone a lot higher if we hadn’t opened the gate to drain off more water in anticipation of the additional rainfall. The heavy rains, warm temperatures, and high winds on Christmas day resulted in most of the lake’s ice melting off. The lake completely froze over for the first time on December 19th. At the time of this writing, most of the lake remains ice free. Continue reading →