Category Archives: Technical Lake Stuff

01 September 2015: August 2015 water level chart archived

I’ve archived the August 2015 water level chart (at left), and what a chart it is. One glance and you can see that the water level hardly moved. For the entire month the lake level never rose above -63″ below the top of the dam and on August 7th it reached -65.16″ below the top of the dam, the lowest level I’ve ever recorded. The lake is so low in fact that water is no longer flowing out of the lake into the outlet channel and hasn’t been since early July; there’s a trickle of water flowing through the open gate in the dam but it is coming from ground water and springs in the meadow area. It’s actually been at or below -60″ below the top of the dam since July 10th. This makes it the longest stretch of the lowest water levels we’ve experienced in the last 4 years. It’s gotten almost this low before, but it has never stayed this low for this long.

The low water condition has been exacerbated by the near-drought conditions we’ve experienced so far this year. As of the end of August we had received only 18.88″ of precipitation for the year compared to 32.83″ on this date a year ago. As a result, because the ground is so dry, there has been no absolutely no runoff as the result of what little rain we have received. To make matters worse, because of the topography of the shoreline around lake, when it does rain the lake doesn’t so much get deeper as it does bigger. This then explains how last August 11th and 12th when we received 2.29″ of rain, the lake only came up 1.92″ total. This defies logic, but as those of you who have stuck sticks in the mud on your water front to mark where the water line is can attest, it ain’t moved.

This extended period of excessively low water levels has severely restricted everyone’s use and enjoyment of Clary Lake even more than usual, not to mention the ongoing impact on wildlife habitat, and water quality. There will be consequences.

10 August 2015: Drained Beaver flowage adds water to Clary Lake

A funny thing happened over the weekend: the lake level which has been falling a consistent 1/4″ daily (due to evaporation only) had, without warning, risen 1/4″ by early Saturday afternoon without us having received any rain at all… This situation had me thinking I’d made a mistake in measuring the water level until I discovered early that evening that the marsh on the south side of Route 126/215 at the primary inlet to Clary Lake which had been recently flooded by beavers was draining into Clary Lake. The picture at left shows the inlet of the culvert well plugged by sticks and mud on Thursday afternoon with the water level less than a foot from the top of the culvert. Sometime early Saturday morning someone, most likely a Town of Jefferson work crew, brought an excavator to the site and dredged out the blockage. Continue reading →

July 2015 Water Level Chart archived

July 2015

I’ve archived the July 2015 water level chart. The most notable thing about it is that it shows the lake level fell to 60″ below the top of the dam on the 9th of the month and remained well below that mark for the rest of the month. It has never been this low for this long. And no wonder given how little rain we’ve received this year: as of July 31st we have received a total of only 15.29″ of precipitation since the beginning of the year. Last year on the same date we had received 29.74″ or almost twice as much. The lake level also fell to a 4 year record low of 62.64″ on July 18th (see 21 July 2015: A new high in lows“). It has since fallen even lower than that, ending the month at 63.48″ on the end of the month.

It’s been so dry this year and especially this past month that when it does rain, very little of it runs off into the lake because most of the precipitation that falls on the ground is being soaked up. This fact, in combination with the topography of the exposed shoreline around the lake, results in a runoff multiplier less than 1x meaning that an inch of rain will bring the lake up something less than an inch. This doesn’t really make sense until until you realize that as the lake level rises it also spreads out, increasing the area of the lake. In other words, when it rains the lake gets bigger, not so much deeper. We’ve seen this phenomena before. How cruel is that?

Because of the berm at the outlet of the lake, very little water is actually leaving the lake now and flowing down the channel to the dam; most of the water that you see flowing out through the dam these days is seeping out of the ground in the meadow area itself, which is quite wet, and also coming in from Clark’s Meadow Brook. As a result, most of the ongoing daily drop in water level (about 1/4″ per day) is due to evaporation.

21 July 2015: Lake level reaches a new high in lows

I don’t need to tell anyone that the lake level is low, that much is obvious. However the lake is now lower than anyone has seen it in more than 54 years judging from a picture taken back in the summer of 1961, and that seems like something worth telling people about. On April 21, 2012 the lake fell to a then-record low of -62.53″ but as of the other day, the lake level had fallen even lower than that, to -62.64″ below the top of the dam, where it sits now. I went over to the State boat launch with my camera to take yet another picture of how useless it is and found the water level had fallen off the end of the ramp. Continue reading →

10 July 2015: Declining water quality, by the numbers [UPDATED]

Get ready for an algae bloom. Jack Holland and I went out and conducted our regularly scheduled water quality monitoring today and the secchi disk reading was only 2.50 meters (8.20′), down from 3.16 meters (10.36′) just two weeks ago. A lake is considered to be experiencing an algae bloom when the secchi disk reading is 2.0 meters or lower. We’re within only 1/2 a meter (1.6′) of that threshold now, and it’s only July 10th. Last year on the 18th of July the secchi disk reading was 3.25 meters (10.66′) and we didn’t approach the 2.0 meter threshold until almost the end of July. We’re good two to three weeks ahead of last year.

I’ve noticed over the past 4-5 days the lake color has gotten decidedly murky and brownish/green but I was still surprised the secchi disk reading so low. I probably shouldn’t have been given how dry it’s been and how low the lake is as these factors contribute to conditions conducive to the growth of filimentous cyanobacteria (aka blue green algae) which are responsible for algae blooms. Once the conditions are right for cyanobacteria to start multiplying, their growth can be explosive.

We’ll take a water sample for phosphorus testing during our next water quality monitoring session in 2 weeks. Phosphorus tests cost $25 a pop to get them analyzed by the State so we usually only do 3 tests per year.

[UPDATE: 7/14/2015] Based on the latest secchi disk reading taken about 1/2 hour ago, Clary Lake is officially having an algae bloom. The reading was 1.95 meters (6.40′). As mentioned above, a reading at or below 2 meters is considered to be an algae bloom.

08 July 2015: Lake shore owners concerned about invasive aquatic plants [UPDATED]

Last week I noticed some large and extensive mats of a green pond weed over by my shoreline in about 2′-3′ of water, thick enough to foul my trolling motor and bring my boat to a halt. I collected a sample and identified it as Elodea or American water weed (or Common Pond Weed). I was therefore not particularly surprised when Thomas Gillette showed up at my house yesterday with a shopping bag full of this plant, concerned that Clary Lake might have an invasive plant infestation underway. Thomas told me that Butch Duncan had brought it to him, saying that there were thick mats of it over in the cove on the north side of the lake by Duncan Road.

I reassured Thomas that this was not an invasive species. We’ve had this plant growing in Clary Lake forever but it’s always remained under control. You’d see a few pieces of it wash ashore from time to time or you might see patches of it up in the channel. Recently however, conditions around the lake have become quite conducive to this plant’s rapid growth in areas where it was not found before. Elodea is not a recognized invasive plant species but under the right conditions it can and does become a nuisance, clogging shallow water areas with thick mats of vegetation. Elodea likes nutrient-rich water down to several meters (5′-7′) in depth, plenty of sunlight, water temperatures between 10° C and 25° C and a soft, silty or muddy bottom where it’s thin wiry roots can get a good foot hold. You won’t find Elodea on a rocky or gravel bottom. With the water level down 5′ and 50% of the volume of the lake gone, conditions around Clary Lake are near perfect for this plant’s growth to explode: the reduced lake volume increases the concentration of nutrients in the water and the lowered lake level allows sunlight to reach down to silty/muddy areas that would normally be under 7′ to 10′ of water where Elodea wouldn’t normally be found, or be able to survive. Now our shallow water areas are a perfect habitat for Elodea.

Continue reading →

June 2015 Water Level Chart archived

6 waterlevelchart_June2015 I’ve archived the June 2015 water level chart. The lake level remained in a fairly tight range for the whole month, fluctuating only ± 3.7″ and ending up the month a little off its lows at -57.36″ below the top of the dam. It fell to 62″ below the top of the dam on June 20th, only the second time in 4 years it has gotten that low. In comparison, during the month of May the lake level fell precipitously at over 1″ per day, for the entire month. Despite the above average amount of rain we received in June (5.46″ compared to an average of 0nly 3.54″) the lake level remained largely unaffected because so much of the precipitation soaked into the ground rather than running off into the lake. As a result, the runoff multiplier was closer to 1X to 1.5X rather than the normal 4X multiplier. May’s rainfall total was so far below average (only 0.60″ compared to an average of 3.7″) that even with all the rain we received in June, we’re still several inches below normal.

The state boat launch remains largely unusable except for carry-in traffic and small boats if you’re able to manhandle them on and off their trailers and are willing to drag them across the rocks and shallows to get to and from deeper water; not many people are. I’ve seen a number of vehicles pull into the launch area with boats on trailers only to leave after seeing exposed rocks off the end of the ramp. Can’t blame them. As a result, boat traffic on Clary Lake this summer is noticeably below normal. Anyone who does manage to get their boat launched has to contend with shallow water and rocks where you least expect them. Only a few of the hazards are marked, leaving vast areas too shallow for safe boating to surprise the unfamiliar boater.

There is ample evidence around the lake of the impact of the ongoing severely low lake levels besides an unusable boat launch, and rocks sticking out of the water. As a result of fluctuating water levels, the loons that call Clary Lake home have not even bothered to try nesting this year, or last. Their last successful nesting attempt was back in 2008. Even more damaging to the ecosystem is the loss of 350+ acres of sensitive, high-value wetlands and the shallow-water littoral zone around the edge of the lake so important for lake health and for bird, fish, and animal habitat. Gone.

13 June 2015: Using the Clary Lake depth map on the lake

When I first posted about the Clary Lake Depth Map last week I mentioned that you could use it with a GPS in real time on a tablet or smartphone. I should have said “in principle” because at the time I actually hadn’t tried it yet… A couple of people asked me about this and I had to tell them that I was still working on it. Well now I have tried it, and I thought I ought to post something more about it. It turns out it DOES work (I knew it!) but it did take a little doing to get it working well out on the lake without an internet connection.

The tricks includ saving the map for “offline use” (see Google Maps “tips and tricks” for how to do this) turning off automatic screen rotation so the app doesn’t try to reload the map, not trying to zoom too much (people with a 3G or 4G data plan from their service provider and who can access the internet anywhere won’t have these issues). Above is a screenshot from my Nexus tablet I took the other day showing the Clary Lake depth map overlaid on Google Maps with GPS positioning enabled (the blue dot with the arrow head and ring around it shows where I was at the time, on my deck). As you move around the lake, the GPS updates your location shown on the map which makes it easy to locate a rock, ridge, or slope where you’re likely to find fish hanging out. How cool is that? This combines things I enjoy a lot, fishing, computers, and using maps. Now if I could just figure out how to convert the depth map into a format that can be uploaded to a Lowrance Mark IV depth finder, I’d be truly happy. You’d think this would be easy.

If you want to give this a try using your smartphone or tablet, first make sure you have location services enabled then copy and paste the following URL into your browser, and head out onto the lake:

https://www.google.com/maps/d/viewer?mid=zb1eVxqneIkk.kyhM9B_EX4Ks

If you try this let me know how you make out. Remember to subtract the current lake level (in feet, presently about 5′) from the depths shown on the map. This will also give you a good idea of areas around the lake to avoid due to lack of water.

05 June 2015: Interactive Clary Lake Depth Map v2.0 now available

Fullscreen capture 652015 114727 AM.bmp (Mobile)

Clary Lake depth map v2.0 (click on the image to view the page)

I’ve added an updated version of the Clary Lake depth map to the site using an embedded Google Map. The page is located under the Charts & Data main menu heading and is entitled “Clary Lake Depth Map” and it’s pretty cool if I do say so myself. This new map has a contour interval of 1 foot and uses dynamically rendered depth labels so as you zoom and pan around the map the labels redraw so you can usually tell the depth of any line you’re looking at. If not you can click on any contour lines and find its depth. The depth contours are also color coded so the darker the line, the deeper it is. There are 8 color ranges, some of which are a little hard to distinguish. Click on the Legend link on the top left corner of the map to see them (if you can’t see the legend symbol, try resizing your browser window). I’ve also added a few colored dots marking rocks and ledges and plan to add a few more as time will permit. You can click on them as well to find out the depth. You can also change the map to use a satellite image instead of the standard terrain base map. Unfortunately, this can make the blue depth contour lines a little hard to see; when I have some time I’ll prepare a map with depth contours intended to be viewed on a satellite image. There are a lot of neat features available with Google Maps and I’m still learning, so expect the map to go through some changes.

Continue reading →

May 2015 water level chart archived

May 2015 Water Level Chart

Behold the May 2015 water level chart. After rising to within 12″ of the top of the dam on 23 April, the lake has fallen steadily to about where it was before the spring melt started back on March 24th. At that time the lake level was at -57.12″ below the top of the dam. At -56.04″ we’re within an inch of that now.

For the month of May, the lake level dropped 35.76″ in 31 days, or about 1.15″ per day, a rate that was negatively affected by the lack of rain. Normally we get about 3.7″ of rain in May which would have offset the fall in the lake level considerably, however this year we received only 0.60″ of rain for the entire month. As a result, as a quick look at the chart will show, the lake level fell every day. Also, because it was so dry, evaporation contributed significantly to the daily water level drop. Since the high on April 23rd, the lake level has fallen 43.32″ in 39 days or 1.11″ per day. Normally you would expect the rate of fall to slow gradually as the level dropped. Below 48″ the usual rate of fall is about 1/2″ per day.

We can all take comfort in knowing that this ongoing ecological disaster won’t be ongoing forever. It will be a little while longer, but normal water levels WILL BE RESTORED.

02 May 2015: Clary Lake water quality monitoring resumes

Water quality monitoring for 2015 resumed on April 30th. David Hodsdon and I tried to get out the previous week but the wind was so strong my anchor was dragging and we couldn’t stay in one place. This date is about average for the first data collection exercise of the year. We’ll try to get out every 2 weeks throughout the boating season. This also marks David Hodsdon’s 40th consecutive year of water quality monitoring for the VLMP. Quite a record!

The water was quite clear with a secchi disk reading of just over 11 feet. You can view current data and that for recent years on our Clary Lake Water Monitoring Data page (we also have data back to 1975 when David Hodsdon started his water quality monitoring efforts, available upon request). Our collection station is over the “deep hole” which we locate with a GPS and the data we normally collect includes air temperature and wind speed, water depth, clarity (secchi disk reading), and dissolved oxygen and temperature measurements at the surface and at 1 meter increments all the way to the bottom of the lake. Approximately 3 times per year we take a core water sample for phosphorus which we send off to the State for analysis. We took one this time.

You can read more about the VLMP and our water monitoring efforts on the Volunteer Lake Monitoring Program page.

01 March 2015: Resumed water level measurements, sort of

Well, not really. I did go over to the dam today and took the picture at left showing some open water between the railroad bridge abutments. By carefully measuring the image using known distances for the length of the southerly abutment (~23′) and the distance between the abutments on the west end (~17′) and after adjusting for the skew angle (simple trigonometry) I came up with a water level value of approximately -48″ below the top of the dam (which is probably within ±3″ of the true value). This value is consistent with the amount of water I observed flowing out of the dam, which wasn’t a whole lot. It is also within a couple of inches of where the lake level was at the end of January when I halted water level measurements. I think the lake level has been fairly stable: while there wasn’t a lot of runoff last month, there’s a lot of snow piled up on the lake and that’s almost the same thing.

At the end of the description of the above picture there’s a link to a full sized version (or click here) on which you can easily see dark stain on the abutment representing the approximate normal high water line, about 1′ below the top of the abutment.

I also added a chart for February 2015 (using precipitation data from the Weather Underground) to the 2015 archive more or less for a place holder since there really isn’t much to look at on it, and I updated the Current Water Level Charts page with a rudimentary chart for March. I’ll try and get an approximate water level more or less weekly until conditions allow me to resume regular measurements. I expect when our awesome 48″ snow pack melts we’re going to see a substantial rise in the lake level.

While I was at it, I corrected the mislabeled January 2015 water level chart which unfortunately claimed to be for December 2014. Nobody noticed, or else nobody bothered to point it out to me.

Think spring!

01 March 2015: A clear and cold start to the month

It was a clear and cold -15° F this morning when I got up, pretty chilly for the 1st day of March. As cold as it has been this winter, it appears the channel has remained open. You can see in the web cam image from this morning that there is some fog up in the northwest end of the lake where the channel starts. This indicates open water. I’ve seen this phenomena off and on this winter when conditions were right. Sure hope the weather starts warming up soon.

I had hoped to resume water level measurements today but the weather is going to have to moderate a lot and a whole load of snow is going to have to melt before I venture down to the lake. There’s easily 6′ of snow on my shoreline and I have no inclination to try floundering through that to find the ice, and then have to chop a hole in it, find my bench mark, yada yada. I will make a point of swinging by the dam today and guestimate the water level at the railroad abutment, that should give us an idea within a few inches of what the lake level is.

January 2015 water level chart archived

And so we come to the end of another month. I’ve archived the first chart of 2015 in a new album “2015 Water Level Charts.” Due to heavy rains in December combined with frozen ground, significant runoff brought the lake level up to 24″ below the top of the dam at the start of the month, right where it would be this time of year if the water level order were being followed. The water level has steadily fallen since the 1st of the year and ended the month at 46″ below the top of the dam.

Like last year, I have decided to halt further water level measurements for the month of February. Weather permitting I’ll resume water level measurements on or about March 1st.

2014 Water Level Charts Archived

And so we come to the end of another month, and for that matter, another year. I’ve just posted the 2014 chart (below) in the 2014 Water Level Charts album. This makes the third full year that I’ve been recording Clary Lake water levels. You’ll notice that last winter I stopped making water level measurements in early February and didn’t resume until April

1st due to cold weather, deep snow, and (for a while) ill health. I’ll keep measurements up as long as practical this winter but I imagine when winter really sets in that I’ll take a break and resume when weather permits.

The December 2014 chart (at left) is interesting. The rainfall we received back on the 9th of the month and over the next few days, though only 1.78″ in total was enough to bring the lake level up fully 16″ and to within an inch of 2 feet below the top of the dam for a runoff multiplier of 9 x (1 inch of rain = 9 inch rise) due to partly melting snow but mostly just because the ground was frozen. In other words, little if any rainfall soaked into the ground. It all ran off (the runoff multiplier during summer months is generally more like 4 x). Subsequent additional rainfall brought the lake level to 22″ below the top of the dam, right about where it would be this time of year if the Water Level Order being adhered to.

I’d also like to take this opportunity to wish everyone a safe and happy New Year’s Eve and a happy and productive New Year. I sincerely hope that 2015 sees the Clary Lake water level order implemented, the lake level restored, and a satisfactory resolution of all the issues surrounding the Clary Lake dam, for all parties. The Clary Lake Association is diligently working to bring these things about. With your help, we will succeed.

November 2014 water level chart archived

November 2014

And so we come to the end of another month. You’ll find the November 2014 water level chart in the 2014 Water Level Charts Album. The lake level stayed in a fairly tight range for the entire month, right around -50″ below the top of the dam, give or take a few inches. It got as high as -48″ at one point and low as -52″ below the top of the dam. With only 2.66″ of precipitation for the month (average is 4.36″) you’d have expected the lake level to have fallen more. However, the ground is fairly well saturated from heavy October rainfall so most of the precipitation we received ran off into the lake. Also, the lake only falls about 1/2 inch per day when it’s at this level so it doesn’t take much precipitation to keep the lake level constant.

And that’s the way it looks from here.

11 November 2014: DEP issues Lake Elevation Survey

The Department of Environmental Protection has released an Elevation Survey for Clary Lake dated October 28th conducted by CES, Inc. , a consulting engineering and surveying firm with offices in various cities around Maine. The field work for the survey was conducted in the vicinity of the State boat launch on October 14th and refers to engineering work completed back in 2002 during the construction of the boat launch. The elevations on the survey are referenced to the NAVD88 elevation datum and are based on GPS measurements.

Clary Lake Elevation Survey

Special Condition 4 of the Clary Lake water level order required the dam owner to retain the services of a licensed professional land surveyor to establish the historical normal high water line of Clary lake. This survey was to have been completed and submitted to the Department by June 2nd of this year. Since the dam owner failed to complete the work as required, the Department of Environmental Protection has done so. This is a welcome development.

The survey concludes that the crest of the dam has an elevation of 151.17′ (NAVD88) and that the highest observed stain line on a rock in the vicinity of the boat launch has an elevation of 151.2′ (NAVD88). Thus, the survey has concluded that the historical normal high water line of Clary Lake is the same elevation as the top of the dam.

October 2014 water level chart archived

I’ve archived the October 2014 water level chart. The lake started the month down about as low as it can get, around 60″ below the top of the dam. It has only been that low 4 other times in the past 3 years. This condition was the result of having received less than average rainfall in August and almost no rain (<1″) in September. While August and September were both short on rainfall, so far this year we’ve received a total of 39.40″ of precipitation, almost an inch more than normal.

03 October 2014: The lake is about as low as it’s going to get

The other day I posted the September Water Level Chart and I speculated at that time that I thought the lake was about as low as it is going to get. Tim Harkins had related how he’d tried to get into the channel and couldn’t find it. Well today I headed out in my kayak to the northwest end of the lake to try to find my way into the channel. I couldn’t. I could see where the water was flowing, but I ran aground in about 3″ of water trying to follow it. I didn’t push it because I didn’t want to get stuck.

The rate at which the lake level has been falling has been dropping off rapidly and as the following plot shows, it has about hit bottom:

Plot of water level versus day number.

The chart shows 36 days of falling water levels starting on August 16th and extending through today. Now I’m not saying the lake can’t fall any lower, but from the looks of that curve it is unlikely. Theoretically it could drop another couple of inches if we continue without receiving any rain, but that is unlikely. Without any rain, springs and water seeping out of the water table is sufficient flow to offset the 1/8″ per day the lake is falling.

What it interesting is that back in April 2012 the lake level fell to 62.25″ below the top of the dam, 2″ lower than it is now. It is hard to imagine the lake falling that low again. I suspect the sediment “dam” blocking the channel is the result of ice pushing against the lake bottom.

01 October 2014: September water level chart archived

I’ve just archived the September 2014 water level chart… and what a month it was. The effect of only having received 0.95″ of rain for the whole month (average is 3.74″) is painfully evident in the slowly but steadily declining water level over the course of the month. The water level is currently 60.24″ below the top of the dam. It can fall further, but not a whole lot further: an examination of the data used to create the chart shows that the rate at which the lake is falling is dropping off fairly quickly. At the beginning of the month it was falling between almost 3/4″ per day. Now, at the end of the month, it is falling about 1/4″ per day. At that rate, it won’t take much rain at all to offset the drop and the lake will bottom out, and stop falling. Last Friday Tim Harkins told me that he’d tried to get up into the meadow in his kayak but was unable to find the channel.

The likely explanation for the situation Tim encountered is that low water conditions combined with ice over the past couple of winters have caused the bottom sediments in the vicinity of the outlet to be pushed up forming a bar of sediment and that this bar is blocking the outlet channel, impeding the flow of water out of the lake and limiting how low the lake get get. This same mechanism- ice pushing against the lake bottom over time- is likely what created the sand bar that can be seen down by the State boat launch. In that case, there was enough water flowing into the lake to cut a channel through the sand bar. It remains to be seen if there’s enough water flowing out of the lake to do the same thing. I doubt it.

Two years ago the lake got down to 63.25″ below the top of the dam. Realistically I don’t think it can fall that low again, but I might be wrong. In any case I intend to go out and try to find the channel myself, later this week. Stay tuned.