Water levels have been sinking in Vermont’s lakes and ponds this summer, and the southern half of the state is in a moderate drought.
Conditions worsened across New England last week, as severe drought conditions developed in parts of Maine, New Hampshire and Massachusetts.
On average, Burlington International Airport gets 23.5 inches of precipitation from January through July, according to the National Oceanic and Atmospheric Administration.
This year, Burlington’s total is only 15.7 inches of rain.
Burlington usually gets 12 inches of rain from May through July, according to the same data set. This year’s number: 7 inches.
Water levels in rivers, lakes and ponds across the state are abnormally low, said Oliver Pierson, lakes and ponds manager at the Vermont Department of Environmental Conservation.
A stream gauge in the Winooski River near Essex Junction, monitored by the U.S. Geological Survey, shows that on Aug. 17, the river normally flows at a rate of 550 cubic feet per second. On that date this year, the flow measured 225 cubic feet per second.
“So, in August of 2020, the Winooski is at half of its normal volume,” Pierson said.
When Tropical Storm Isaias swept through the state on Aug. 4, providing a pulse of rain, levels briefly surged, but quickly returned to well below average, where they remain.
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“You can look at that, really, at almost any river in the state,” Pierson said. The Lamoille River, in the northern part of the state, and the West River, on the state’s southeastern edge, both have abnormally low flow.
Levels in lakes and ponds are also far below normal. Roger Hill, a Worcester-based forecaster, says the water level in his backyard pond is lower than he’s even seen it, having lived on the property since 1998.
“It’s down about 16 inches,” he said. “The entire summer, right from the spring, we’ve been below level.”
Hill expects Vermont will get more rain in the coming week, but not enough to reverse conditions in the state.
“We’re sort of a cumulatively losing ground with this,” Hill said. “We typically need about about an inch a week this time of year to keep us from slipping into drought.”
With above-average rainfall in 2019, Lake Champlain’s water levels were high in the beginning of the year. On Jan. 15, the water sat at 97.6 feet above sea level — a whole 2 feet above average.
Now, the water in Lake Champlain sits at 94.5 feet above sea level, having fallen more than 3 feet in eight months.
“We’re at about one and a half feet below the average lake level,” Pierson said. “That’s a big deal for a lake as large as Lake Champlain.” The lake has 435 square miles of surface water, according to the Lake Champlain Land Trust.
The lake’s water temperatures are also setting records. On June 23, average water temperature in Burlington Bay is 62 degrees Fahrenheit. This year, it was 79.
Vermont’s 800 lakes and ponds are running from 6 inches to 2 feet below average this summer. But levels are not yet low enough for residents to worry about drinking water supplies, Pierson said.
Edward Stromberg, president of Putney-based Green Mountain Well Co., reports an increase of 10 to 15 percent in the number of callers having problems with their wells in southern Vermont.
“The shallow wells are starting to have problems,” he said. “It’s starting about a month and a half early. Usually they start showing up in September to late October. … This year they started showing up at the end of July.”
Jesse Kayan, who owns Brattleboro-based Wild Carrot Farm, said the drought has affected his yield. While the farm has been bolstered by increased interest in its summer CSA, Kayan decided against offering the farm’s winter CSA, partly because of trouble growing winter squash, potatoes and onions.
“Those are the things that kind of carry us through the winter, the heavy producers,” he said. “And that was all water-related.”
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Other farmers have told him the dry early-summer conditions are rare for Vermont.
“Their perspective was that it had never been as dry as it was at that time of the year,” he said. “It’s not that it never gets that dry; it’s that it never happens that early in the season.”
Pierson said water quality could become a concern in lakes and ponds if dry conditions continue. With less water, concentrations of nutrients have greater impact on plant growth, so swimmers may be wading into weedier, shallower water. Warmer temperatures are also ideal for the growth of blue-green algae, which can be toxic when ingested.
However, the lack of precipitation means less runoff from sources like agricultural fields, which can mitigate the algae problem.
Pierson said more stretches of dry weather, punctuated by occasional heavy rain, will likely become more common as Vermont feels the effects of climate change.
“I think what we need to be preparing for is more fluctuations in both precipitation and temperature,” he said, “and being prepared to absorb large precipitation events, but then, as we’re seeing this year, being able to deal with long periods of below-average precipitation.”
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