May 2022 Water Level Chart Archived

5 Clary-Lake-Water-Level-May-2022

May 2022

I have archived the May 2022 Water Level Chart (at left). From the beginning of the month on we saw an abrupt change from the above-average precipitation which has been the norm for the first 4 months of the year, almost as though someone had turned off the spigot! Total rainfall for the month was only 1.34 inches, well short of the normal 3.71 inches. Because we were 3.78 inches above normal at the end of April, we’re still 1.41 inches ahead of where we’d be in a “normal” year. However, simply looking at total precipitation gives you an unrealistic picture of actual ground water conditions: the fact of the matter is, the entire coast of Maine including Clary Lake is considered to be “Abnormally Dry” by the USDA Drought Monitor program.

Just how drastically short of precipitation May was is evident from a look at the 2022 Precipitation chart (below). The green line represents average rainfall and you can see that in May, we never even got close to it. Granted, March fell a little short of average, but April made up for it. The fact that the lake stayed as high as it has through the month of May is simply a result of our efforts to preserve water by minimizing outflows at the expense of minimum flows. For the first half of the month the lake level never varied more than a couple of hundredths of a foot from the top of the dam elevation. Then when it appeared the drought conditions were going to continue, we closed the gate completely. As expected, continued dry weather and a depletion of ground water led to a slow but steady decrease in the lake level, the majority of which has been due to evaporation. Also, when ground water levels are high, water seeps out of the ground to at least partially replace water loss. When ground water levels are low as they are now, water is actually wicked up into the surrounding shore line, contributing to the lake level dropping.

Since the middle of the month, the lake level has dropped all of 2.25 inches to a low for the month of -0.49 inches below the HWM, lower than usual for this date but still high by historical standards. Dam leakage is currently estimated to be only 2 CFS (cubic feet per second) which accounts for slightly less than an inch of water level loss. Even a modicum of rainfall would be more than enough to maintain the lake level. Fortunately, according to the Maine Climate Office the precipitation outlook for the next 8 to 14 days is 40% to 50% above normal and it won’t take much rain to make a big difference in our lake level. Currently the lake is somewhat lower than it has been on this date in the previous 3 years. You can see just how much lower it is on this chart from our 2022 Dam Operation Log comparing lake water levels for 2019, 2020, 2021, and 2022:

Given the circumstances, I think we’re lucky the lake level isn’t lower than it is.  Here’s hoping we get some rain soon!