New Candlewood Lake Authority (CLA) Executive Director Mark Howarth and CLA Chair Phyllis Schaer led the CLA’s annual State of the Lake event April 22 at the Sherman Fire House. The informative afternoon covered a variety of lake-related topics including an overview of the triploid grass carp program, and presentations by two Western Connecticut State University professors on the carp tracking program and cyanobacteria (blue-green algae) testing.
Mr. Howarth, who was promoted to the Executive Director position last month, kicked the event off with an overview of the history of Candlewood Lake. He noted that 2018 marked the 90th anniversary of the creation of the lake. It was constructed by 900 people over the course of 17 months at a cost of $5 million. He noted that while the lake has had a good history, it faces some challenges, specifically the threat of invasive species such as Eurasian Milfoil and increasing amounts of nutrients and other products of increased development around the lake over the past several decades.
In 2016, there were 506 acres of milfoil in the lake. In 2017 the number dropped to 498 acres. The grass carp program was started in 2015 when 3,850 sterile grass carp were released into the lake. Most of these fish were 12″-14″ in size, except for some larger 16″ fish that were released in the northern portion of the lake near the pumping intake. Fish in this area needed to be larger so that there was less chance of any being pumped out of the lake into the Housatonic River when water was needed to generate power. In 2016, 48 carp were equipped with tracking devices so that enabled researchers to follow their movements and determine if they were staying in the milfoil beds.
A second group of 4,450 carp were released into the lake in 2017, bringing the ratio of carp to the 15 per vegetated acre ratio recommended by the CT Department of Energy and Environmental Protection (DEEP). He also stated that for the first time, 585 carp were added to Squantz Pond as well. Over time the carp will grow and hopefully catch up to control the rate of milfoil growth. Mr. Howarth explained that the carp act like “lawn mowers”, grazing on plants from the top down. He said that DEEP will approve the addition of more carp in the coming years to account for carp attrition.
Dr. Theodora Pinou, Professor of Herpetology, at Western Connecticut State University gave a presentation on triploid grass carp and the fish tracking program that she and two student interns have been working on since 2016. Using 2014 weed bed maps, the team identified four locations in the New Fairfield, Candlewood Lake Club, Sherman, and Danbury areas of the lake. They released 12 tracking device-equipped carp into each of the four sections to see if they would stay to graze in the weed beds or if they would move to other areas of the lake. By and large, the fish have remained in the milfoil weed beds, where the food supply is most plentiful.
Dr. Pinou encouraged those present to be “citizen scientists” when they are out on the lake by becoming familiar with what a triploid grass carp looks like and taking pictures of any dead fish they might come across and emailing those pictures to herself at Westconn or to the CLA with CARP PROJECT in the headline.
Mr. Howarth then gave an overview of the 2017 Water Quality Report that had been assembled by Aquatic Ecosystem Research (AER). In addition to 2017 water quality data, AER was able to draw upon 33 years of data and analysis compiled by the CLA, university studies, and other accumulated documentation which enabled the firm to put results in context.
While water quality in both Candlewood Lake and Squantz Pond has improved in general over the past several years, conductivity levels have increased, particularly in Candlewood Lake. According to AER’s executive summary, the increase in conductivity appears due in large part to increasing concentrations of sodium, calcium, magnesium, chloride and possibly, alkalinity. pH levels in Candlewood are also increasing. AER also found that Candlewood and, to a lesser degree, Squantz are experiencing changes in seasonal patterns of stratification, or the layering of water temperatures by depth.
Mr Howarth noted that these factors create an environment favorable to blue green algae and unfavorable to competing algaes. When the temperature is right, this environment favors blue green alae blooms. While increased lake stratification is most likely due to climate, Mr. Howarth stated that increased levels of dissolved salts—sodium, chloride and magnesium—were likely due in large part to road salt usage on state, town and private roads around the lake.
This led to a presentation by Dr. Edwin Wong, Associate Professor of Molecular Biology and two of his students, Robert McArthur and Kayla Zhang on the cyanobacteria testing they have been conducting around Candlewood Lake and Lake Zoar. Dr. Wong explained that while all types of cyanobacteria, also known as blue-green algae, can produce harmful toxins, they do not produce them all the time. It takes a variety of environmental triggers to do this.
His team has been sampling water from the town parks in Candlewood Lake and from Eichler’s Cove, Jackson Cove, and Kettletown State Park on Lake Zoar for the last couple of years. In 2016, all samples the team took were well below the acceptable level of 4 parts per billion (ppb), set by the EPA. In fact, no samples showed even 1 ppb. However in August of 2017, levels were alarmingly higher, with some samples taken from Kettletown State Park at as much as 18 ppb. Samples in Candlewood, while not as high, were elevated as well.
While he said the factors driving this increase were not clear, Dr. Wong hypothesized that it may have been due to increased nutrient levels and climate conditions. He noted that on a national level, particularly in California and Florida, reported levels were even higher.
Ms. Schaer noted that samples taken by Dr. Wong and his team are analyzed at WCSU and reported to DEEP. The method used has a quicker turnaround to other testing methods used by the University of Connecticut and has proven just as accurate. This potentially shortens the time beaches remain closed when bacteria levels are high.
The event concluded with presentations by the CLA Marine Patrol, the Wood Duck Project, and the New Fairfield Senior Environmental Corps. The Corps was established in 2005. The group collects water samples from 18 sites weekly to test for bacteria. The Corps will hold an informational meeting on May 8 at 9:00 am in the New Fairfield Senior Center for anyone interested in joining.
The Wood Duck Project was started over ten years ago to reintroduce wood ducks to the lake. So far the project has erected seven wood duck boxes. Currently there are two mature nesting pairs and four younger pairs in residence with some single males and females in the area.
Items the CLA is currently working on is the institution of a boat decontamination unit to prevent the spread of invasive species to the lake, a lake-friendly living homeowner’s guide, and an overall lake management plan for the lake. The annual Candlewood Lake Cleanup day is scheduled for May 19.
By Greg Slomba