Weed Committee Co-Chairpersons: David Adilman and Mark Florio
Members: Dick Tyler, Judy Lugus, Steve Ellis, Bill Mooney, David Pollack, Eric Lynn, David Whitefield, Bill Smith, Amy Janovsky, Kenny Tamarkin, and Janet Kenney.
Fundraising Committee Chairperson: Marty Rabinowitz
Members: David Adilman, David Brown, Steve Cotton, Steve Ellis, Janet Kenney, Judy Lugus, Arno Minkkinen, Sandy Minkkinen, Tabatha Ross, and Dick Tyler.
2011: First Whole-Lake Fanwort Treatment in Six Years
Post-Treatment Survey Finds No Trace of Fanwort
2010: Focus on the New Invader, Spiny Naiad
2009: Fanwort Spreads, and New Invader Appears
2008: Where Has All the Fanwort Gone?
2007 Weed Program In Action
2007 Weed Agenda
2006 Weed Program In Action
2006 Weed Agenda
2005 Weed Program: Assessing the Progress
Will hydro-raking spread the cabomba?
What are those huge floating things that look like pineapples? What can we do to treat the water lilies that come back?
What's the effect of the dead fanwort on the O2 and pH levels?
Why has the Pond become a Gatorade color?
What has the effect been on native plants?
What will the Pond look like over the next few years?
Would a drawdown and hand-pulling have done the job?
Should we train "weed-watchers" to look for fanwort outbreaks?
Why is there increased pondweed in Frye's Brook?
2005 Weed Program in Action
Making It Happen: The Last Few Steps
Putting a Program in Place: Getting Approvals
Developing a Program: The Study and What it Recommends
Read more about the elements of the recommended program:
How does Sonar work?
Is there much experience with its use?
What will the effects be on shallow wells?
Are there swimming or fishing restrictions?
Is Sonar a permanent solution?
Post-Treatment Survey Finds No Trace of Fanwort
December, 2011
The Foster's Pond Corporation's lake management consultant slowly wound his way around the Pond in a small boat in September, examining the results of this year's weed treatments. At 50 locations, he dragged a rake across the bottom and tallied the vegetation it picked up.The good news: He found a healthy variety of native plant species. The even better news: He didn't find fanwort and Brazilian elodea, two non-native invasives that were targeted in herbicidal applications earlier in the summer.
The last time the entire 120-acre Pond had been treated was
2005, when fanwort had overwhelmed native species to become the dominant plant throughout Foster's Pond. In 2007, 19 acres were spot-treated. Pond-wide surveys in 2009 and 2010 found only small fanwort colonies in the Main Pond, but by then it was growing densely throughout much of the Channel. The 2011 treatment was aimed at controlling the fanwort before it again took over the entire Pond.
September, 2010: Fanwort in the Channel. In addition, another non-native was found in 2010 carpeting the bottom of Dug Pond, the Town-owned 3.9-acre swimming hole which drains into Foster's Pond and is separated from the larger
water body by a narrow berm. Dug Pond was also targeted for treatment in 2011.
July 7: Brazilian elodea from Dug Pond, just before treatment. The non-native invasive had become widespread in Dug Pond, but had not yet moved to adjacent Foster's Pond. On May 13 and again on June 24, technicians from the Corporation's lake management consultant, Aquatic Control Technology, zoomed around the Pond in an18-foot airboat applying time-release pellets and a liquid formulation of fluridone (sold under the brand name Sonar), the only registered for aquatic use in Massachusetts that is effective in controlling fanwort. They airboat was equipped with a calibrated spreader and pumping unit, linked to a GPS unit which was used for navigation to ensure that the herbicide was applied in the right concentration.
GPS track of the airboat on its June 24 run. Click on the image above to see an enlargement. A key to effective use of Sonar is maintenance of a low but consistent concentration of the slow-acting chemical in the water over an extended period. The target concentration, in parts per billion, is lower than that allowed in public drinking water supplies. Sonar prevents green plants from producing yellow pigments which protect chlorophyll from breaking down under sunlight. Without the yellow pigments, the plants slowly bleach out and die. The process (called “chlorosis”) can take upwards of 6 to 8 weeks - an advantage, since the slow dying avoids sudden oxygen depletion (which could result in fish kills) or nutrient release (which could result in algae blooms).
Map of the 50 data collection points, established in 2004, for consistent monitoring of vegetation in the Pond. Click on image above to view an enlargement. The results could hardly have been better. Fanwort was already showing signs of Sonar exposure within a month after the first 2011treatment, and chlorosis progressed throughout the summer. ACT conducted comprehensive post-treatment survey on September 19, using a set of 50 data points established in the Corporations 2004 vegetation survey and utilized in four subsequent surveys. The consultant’s final 14-page treatment report, which was submitted to the FPC on December 20, states that during the September 19 comprehensive survey, “no viable fanwort was found anywhere in Foster’s Pond.”
The Brazilian elodea in Dug Pond (which had no fanwort to speak of) was treated on July 7 with a different herbicide, diquat (sold under the brand name Reward). ACT reported that this “treatment worked very well,” and that “[n]o Brazilian elodea was found in Dug Pond following treatment.”
No further weed treatments are planned for 2012, but the Corporation will closely monitor aquatic vegetation in the Pond. After earlier treatments, the range and variety of native plants increased, providing better habitat for fish and wildlife and a more balanced ecosystem.
"PurLoo Beetles" Join Their Cousins to Attack Invasive Weeds
July, 2011
The Foster's Pond Corporation has turned to nature for help in combating purple loosestrife, a widespread invasive weed that has been expanding along the shores of the Pond, driving out native species such as cattails.Hand-pulling the deeply-rooted plants is virtually impossible when there are acres of them to deal with, and herbicides are a last resort. The solution recommended by the FPC's lake management consultant: beetles.
July 22: Beetle wrangler Suzanne Robert lifts a net from a potted purple loosestrife plant, freeing the "PurLoo beetles" she has raised. The nearest patch of their favorite food is a stand of purple loosestrife choking an area between Azalea Drive and the mouth of the Mill Reservoir. "PurLoo beetles," as they are called by environmentalists who advocate their use, prefer purple loosestrife to all other plants, and although they have been known to dine on the occasional rosebush, they will return to the purple loosestrife to lay their eggs. And there's plenty of purple loosestrife around Foster's Pond to keep them happy.
With the help of Andover's Conservation Department, the FPC teamed up with "beetle wrangler" Suzanne Robert. A scientist at
the Massachusetts Department of Environmental Protection's Drinking Water Program, Ms. Robert has been raising "PurLoo beetles" on her own time for the last three years, working with municipalities and environmental organizations to release them in various wetlands.
About 3/4 of an acre of purple loosestrife took over the passage between Azalea Drive and the mouth of the Mill Reservoir last summer. She collects beetles and larvae in the wild, placing them on potted purple loosestrife plants surrounded by netting. When the larvae have sufficiently matured, the pots are set on dry land near the targeted patches of purple loosestrife, the netting is removed, and the beetles are free to dine. They can range up to half a mile in search of their favorite meal.
Some purple loosestrife plants, unfortunately, have a built-in advantage that lets them survive the beetle. The beetles propagate twice each summer, and to do so, they must climb down the host plants to the soil. But if those host plants are rooted in standing water, the beetles will drown or get eaten by predators - and a lot of the purple loosestrife in Foster's Pond grows in standing water.
Last summer, dam repairs and an ensuing drought exposed an area between Azalea Drive and the the old Frye's Dam at the
mouth of the Mill Reservoir, leaving that area high and dry. Purple loosestrife took root and flourished. It now covers upwards of three-quarters of an acre in that area alone, but with normal water levels restored, the plants are in standing water. As a result, even though many of them are being eaten by "PurLoo beetles," those beetles are doomed as the summer wears on.
Purple loosestrife on the shore of the Main Pond. It's an invasive weed which drives out native species and is very difficult to control. That's where Ms. Robert's home-grown beetles come in. With help from FPC President Steve Cotton, she brought five potted plants to the area, each hosting beetles she had raised in her driveway. They were positioned on the peninsula directly across from Bessie's Point, and as she removed the netting and merrily encouraged the beetles to take wing, she estimated that there were about 200 of them to join those already attacking the target plants. The difference is that the newcomers are likely to return to the potted plants on which they were raised and will not drown in the course of producing a new generation. The pots will be left in place over the winter, so that another generation will get an early start attacking purple loosestrife in the vicinity next spring.
Ms. Roberts suggested that to make a real dent in the purple loosestrife infestations around the Pond, area residents should raise and release the beetles, which she said is a pretty simple and inexpensive task. She offered to provide instruction to volunteers next spring. She added that she is an avid organic gardener, and that even though the beetles sometimes get loose, she has never seen damage to any of her flowers or vegetables.
Dug Pond Gets Its Reward
July, 2011
July 7: Technicians from Aquatic Control Technology treat Dug Pond. The herbicide is infused into the water from hoses trailing on both sides of the boat. Dug Pond was treated with diquat (sold under the brand name Reward), in an effort to rid the 3.9-acre swimming hole of Brazilian elodea, a non-native invasive weed.
Technicians from the Foster's Pond Corporation's lake management consultant, Aquatic Control Technology, circled
July 7: Brazilian elodea from Dug Pond, just before treatment. The non-native invasive had become widespread in Dug Pond, but had not yet moved to adjacent Foster's Pond. Dug Pond in a small boat trailing hoses to infuse the pond with a dilute formulation of the herbicide, which is expected to kill the weed over the next several weeks. Native species in Dug Pond will rebound following the treatment.
The Town-owned basin on Glenwood Road Extension feeds into the rest of Foster's Pond, and if left untreated the Brazilian elodea would almost certainly find its way into the larger water body. A common species in home aquariums, Brazilian elodea can spread quickly in the wild, driving out native plants.
Dug Pond was treated on July 7. It was closed for the day to boating, swimming and fishing. Residents were advised not to use treated water for irrigation for five days.
Dug Pond to Be Treated July 7
July, 2011
Dug Pond will be treated July 7 to combat a spreading infestation of Brazilian elodea, an invasive weed that last yearspread throughout the 3.9-acre swimming hole just off Glenwood Road Extension.
Dug Pond lies on the right shoulder of the flying duck. For an enlarged map, click on the image above. The Town-owned basin is part of the Foster's Pond watershed, and empties into the larger water body. Dug Pond is separated from Foster's Pond by a narrow berm.
Dug Pond will be closed to fishing, boating and swimming for the entire day. Residents are advised not to use treated water for irrigation for five days.
Brazilian elodea taken from "Dug Pond" in 2006. A Sonar treatment aimed primarily at killing fanwort also slowed the Brazilian elodea that year, but since then it has spread. Diquat will be used this time, as it is more effective against Brazilian elodea. Dug Pond will be treated with diquat (sold under the brand name Reward), the mostly widely used aquatic herbicide in Massachusetts and other Northeastern states. Diquat has been used previously in Foster's Pond. It was applied to 3.25 acres of the Main Pond last year to spot-treat for spiny naiad. Diquat is registered for use in the vicinity of shallow wells; it binds quickly with sediments, so that it does not travel through soils.
The treatment is part of a plan approved by the Andover Conservation Commission.
"Booster" Shot Zaps Weeds; Dug Pond Is Next
June, 2011
June 24: Airboat skims the Main Pond, injecting a "booster" treatment of Sonar below the surface. The Pond received a second dose of Sonar on June 24, six weeks after an initial treatment of the herbicide had begun to decimate nuisance weeds that were staging a comeback.
Technicians roared over the Pond in an 18-foot airboat, dragging hoses that diffused low concentrations of the slow-acting weed-killer, the only approved means of controlling the Pond's most menacing invasive, fanwort.
Residents are advised not to use Pond water for irrigation until August 14. Swimming, boating and fishing are allowed at the low concentrations used for treating fanwort.
As expected, Brazilian elodea has re-appeared in Dug Pond, and a treatment with diquat is tentatively scheduled sometime during the week of July 4. Following that treatment, water from Dug Pond should not be used for irrigation for 5 days.
These treatments are taking place in accordance with a plan approved by the Andover Conservation Commission.
Weeds Start to Fade; Pond Will Get "Booster" Treatment June 24
June, 2011
The Pond will be closed for boating, fishing and swimming on June 24, when the airboat will return for a "booster" treatment with the slow-acting herbicide that is already bringing a faded look to fanwort and water lilies throughout the Pond.This year's Pond-wide treatment of nuisance weeds has sharply reduced problem vegetation, just six weeks into a three-month regimen. Fanwort - which, without the treatment, would appear a luminescent green and by now be choking the Channel - instead is showing sickly white tips. Lily pads are pallid, too, and both species are growing much more slowly than usual.
It's all due to Sonar, the slow-acting herbicide the Corporation is
using to combat fanwort. Sonar works by interfering with the plants' ability to produce yellow pigments which protect chlorophyll from breaking down under sunlight. Without the yellow pigments, the plants slowly bleach out and die. The process (called "chlorosis") can take upwards of 6 to 8 weeks to start - an advantage, since the slow dying avoids the prospect of sudden oxygen depletion (which could result in fish kills) or nutrient release (which could result in algae blooms).
June 21: Fanwort in the Channel showing signs of chlorosis - the bleaching effect triggered by Sonar. Nuisance weeds throughout the Pond are fading. The trick is to maintain a low concentration of Sonar in the Pond over a 60- to 90-day period. Since the Sonar itself breaks down, and works at extremely low doses, effective treatment requires monitoring, with one or two "booster" shots if concentrations fall too far.
Last week, the Corporation's lake management consultant, Aquatic Control Technology, sampled the Pond and found concentrations of 10.6 parts per billion (ppb) near the dam and 17ppb in the Channel. The target concentration is between 10 and 20 ppb. Environmental regulators allow concentrations of Sonar up to 20 ppb in public drinking water supplies, and even though Foster's Pond is not used for drinking, the FPC requires the concentration to be kept below this threshold.
Still to come as part of the FPC's 2011 weed program: treatment of Dug Pond with diquat, if Brazilian elodea re-emerges this year; and release of beetles which dine on purple loosestrife, which last year began to choke the passage between Azalea Drive and the mouth of the Mill Reservoir.
Treatment Starts Under Ideal Conditions
May, 2011
Mother Nature could hardly have been more cooperative as technicians launched their airboat to begin the Corporation's 2011 assault on fanwort.
May 13: Sonar treatment of Foster's Pond begins under cloudless skies. Under sunny skies, Aquatic Control Technology senior biologist Marc Bellaud gunned the prop, steering the craft into the Pond's shallowest coves as it sprayed herbicide-laced pellets into the areas of heaviest fanwort concentration. The pellets release the herbicide over an extended period.
The entire Pond was treated in accordance with a plan approved by the Andover Conservation Commission. Most of open-water areas were infused with a liquid solution of the slow-acting weed-killer, the only effective method authorized in Massachusetts for controlling the invasive weed which once dominated the Pond.
The Pond was closed to fishing, boating and swimming for the day. Pond water should not be used for irrigation for the next 90 days, but there are no restrictions on recreational uses of the Pond after the day of treatment. At the low concentrations at which the Sonar was applied - less than 20 parts per billion - it is permitted in municipal drinking water reservoirs.
Weed Treatment Set for May 13
May, 2011
Foster's Pond will be treated for invasive weeds on Friday, May 13. Fishing, boating and swimming will be prohibited throughout the Pond for the day. Signs will be posted at strategic locations warning visitors and residents to stay out of the water.Residents are also advised not to use Pond water for irrigation
until August 14. A low concentration of Sonar herbicide will be maintained throughout the 90-day treatment period, and using treated water on tender land plants is not recommended.
Fanwort in full bloom. At the concentration used in the Pond - under 20 parts per billion - Sonar is permitted in public drinking water supplies, and it is ok to fish or swim in the treated water after the first day of application.
An inspection of the Pond on May 6 found the target weed, fanwort, was actively growing. The ideal time to begin treatment is when the plant starts emerging in the Spring.
A decision will be made on Friday whether to treat Dug Pond for fanwort. If no plants are visible, no Sonar will be applied. Dug Pond will be treated later for another invasive, Brazilian elodea.
This year's treatment - the first time in six years that the entire Pond has been treated for invasive weeds - is being undertaken in accordance with a plan approved by the Andover Conservation Commission.
Conservation Commission OK's 2011 Treatment Plan
April, 2011
The Andover Conservation Commission has unanimously approved the FPC's plan for treating Foster's Pond and Dug Pond this Summer to control invasive weeds.The routine vote, which was expected, clears the way for the first whole-lake treatment of the Pond in six years.
The plan calls for treating all 120 acres of Foster's Pond in mid- to late May with a low doses of liquid fluridone (sold under the brand name Sonar), the only herbicide approved in Massachusetts for the control of fanwort. Areas of the Pond showing the highest density of fanwort will simultaneously be treated with slow-release pellets. In addition, Dug Pond will be treated for another invasive weed, Brazilian elodea.
Corporation Sets Sights on Fanwort Treatment This Summer
March, 2011
The Foster's Pond Corporation has endorsed a plan to treat the entire Pond this Summer - the first whole-lake weed treatment in six years - to control the spread of fanwort. The plan also calls for treating Dug Pond to rid it of another invasive weed, Brazilian elodea.The treatment program will cost about $50,000, all of which will be paid by the Corporation.
Map from the treatment plan for 2011 shows concentrations of fanwort near the dam, throughout the Channel, and along the shoreline near the foot of Snowberry Road. Some stands were also found in the Main Pond, though nothing like the densities seen in 2005. To view a larger image, click on the map. The treatment plan, approved by the Corporation's Board of Directors in January, has been submitted to the Andover Conservation Commission. The Corporation has been designated by the Conservation Commission to undertake an integrated lake management program to protect Foster's Pond.
The treatment plan was prepared by the Corporation's lake management consultant, Aquatic Control Technology.
The plan calls for treating all 120 acres of Foster's Pond in mid- to late May with a low doses of liquid fluridone (sold under the brand name Sonar), the only herbicide approved in Massachusetts for the control of fanwort. Areas of the Pond showing the highest density of fanwort will simultaneously be treated with slow-release pellets.
The treatment plan for 2011 calls for the areas outlined in red - which have the highest densities of fanwort - to be treated with slow-release pellets. The entire Pond will be treated with liquid Sonar, as well. The aim is to maintain a low but steady concentration of Sonar in the Pond for several weeks. It is anticipated that one or two "booster" treatments of Sonar will be needed to maintain a target concentration of 5 to 12 parts per billion. That level, which is sufficient to kill fanwort, is far below the 20 ppb concentration allowed by regulatory agencies for use in public drinking water supplies. Even though no residents use the Pond directly for their drinking water, the Corporation seeks to use the minimum dose needed to control nuisance invasives.
Sonar was used to treat the entire Pond in 2005, when fanwort had become the dominant plant in most of the Pond, covering nearly half of the open water. Left unchecked, fanwort can literally choke a Pond to death. The results of that first treatment were astonishing, virtually eliminating fanwort throughout the Pond.
But any such treatment is a temporary fix, and many water bodies must be treated every two or three years to keep fanwort from taking over. In Foster's Pond, 18 acres between Mill Reservoir and the dam were re-treated in 2007, though the rest of the Pond remained almost fanwort-free. An aquatic plant survey in 2008 found fanwort in less than 1% of the Pond (as opposed to 50% before the 2005 treatment), and in 2009 it covered just 6.1% (one-ninth of its pre-treatment infestation). In 2010 - three years after the "spot" treatment - fanwort was returning to nuisance levels in the Channel. It was also showing up in the Main Pond. But five years after only one treatment, fanwort levels in the Main Pond have remained far below their pre-treatment densities.
2004: Pink, blue and lighter green areas are mostly fanwort. The darker green denotes water lilies. Black is open water. (Dug Pond wasn't surveyed in '04). 2008: The greenish areas denote water lilies. The blue is open water. That little spot of pink is the only significant colony of fanwort. (Click the images for larger maps.) Previous fanwort treatments have had no adverse effects on fish or wildlife, and have allowed beneficial native plants to re-establish themselves. The 2009 plant survey found 23 native submersed or floating plant species, compared to 11 found in 2004. Native plant species provide better habitat for fish and wildlife than fanwort, which grows in thick mats which overpower other plants.
The treatment plan also calls for a single application of diquat
(sold under the brand name Reward) in Dug Pond during June to control Brazilian elodea. Diquat is the mostly widely used aquatic herbicide in Massachusetts and other Northeastern states, and was applied to 3.25 acres of the Main Pond last year to spot-treat for spiny naiad. Diquat is registered for use in the vicinity of shallow wells; it binds quickly with sediments, so that it does not travel through soils.
Brazilian elodea taken from "Dug Pond" in 2006. A Sonar treatment aimed primarily at killing fanwort also slowed the Brazilian elodea, but since then it has spread. Diquat will be used in 2011 to control this invasive in Dug Pond. The treatment program will require temporary water use restrictions this summer. Although not required by the EPA product labels, all of Foster's Pond and Dug Pond will be closed for swimming, boating, and fishing on the day of any treatment. Water from Dug Pond should not be used for irrigation (or for drinking or watering livestock) for five days following treatment with diquat; water from Foster's Pond should not be used for any of these purposes for 30 days following the final application of Sonar.
Next Up: Consultant Recommends Pond-Wide Fanwort Treatment in 2011
December, 2010
The Corporation's lake management consultant has recommended treating Foster's Pond next Summer to control fanwort, which has slowly grown back to nuisance levels in the Channel and has begun to re-establish itself throughout the Pond.A report presented this month by Aquatic Control Technology's senior biologist Marc Bellaud shows "moderate to abundant densities" of fanwort near the dam, throughout the Channel, and along the shoreline at the foot of Snowberry Road. Colonies of the weed - which once dominated the Pond - were also found in the Mill Reservoir and among dense waterlily beds in the Main Pond.
Map from ACT's 2010 report shows concentrations of fanwort near the dam, throughout the Channel, and along the shoreline near the foot of Snowberry Road. Some stands were also found in the Main Pond, though nothing like the densities seen in 2005. The report notes that fanwort remains far less dense than it was in 2005, when the 120-acre Pond was choking on the non-native invader. Fanwort (Cabomba caroliniana) is an aquarium plant that, once it finds its way into a New England pond, can take over, driving out native plants, destroying habitat, and eventually becoming so dense that fish suffocate and the lake dies. A treatment of the whole Pond in 2005, followed by a "spot" treatment of 18 acres in the Channel in 2007, kept the fanwort in check. Since many ponds require re-treatment every couple of years to stop the spread of fanwort, a six-year span between whole-lake treatments is regarded as an excellent result.
2005: Fanwort in the Main Pond prior to treatment Only one herbicide is currently approved in Massachusetts for the treatment of fanwort. Fluridone (marketed under the brand name "Sonar") works by blocking the plant's production of yellow pigments which protect chlorophyll from breaking down in sunlight. Without the yellow pigments, the chlorophyll bleaches out, the plant can't produce the food it needs, and it dies. The process is called "chlorosis," and it takes at least 6 to 8 weeks to kill the plant. Biologists regard the slowness of the process as a good thing, since a more rapid die-off would run the risk of depleting oxygen in the Pond. Sonar is applied both in spray form and through slow-release pellets.
After the 2005 treatment, no adverse effects were observed in fish or wildlife, and native plants re-established themselves in greater density and variety than before the treatment.
Sonar, at the concentrations used for fanwort treatment, is considered by regulators to be safe for use in public drinking water reservoirs right up to the intake pipes.
The ACT report was based on surveys of the Pond conducted on September 1 and November 12.
Brazilian elodea taken from "Dug Pond" in 2006. A Sonar treatment aimed primarily at killing fanwort was also taking out the Brazilian elodea. Healthy plants are bright green, with no pink or white. Fanwort disappeared from Dug Pond,but the Brazilian elodea hung on. The survey found no fanwort in Dug Pond, the 3.9-acre Town-owned swimming hole separated from the rest of Foster's Pond by a narrow berm. But Bellaud found "healthy growth" of another invasive weed, Brazilian elodea, which had been detected in small amounts in previous years. Brazilian elodea carpeted stretches along the shoreline, leading ACT to recommend treating Dug Pond with a different herbicide, diquat (marketed as "Reward"). Diquat is less expensive than Sonar, and may be more effective against Brazilian elodea,but diquat has no effect on fanwort. Two areas of the Pond were treated last Summer with diquat in order to wipe out newly-discovered colonies of yet another invasive weed, spiny naiad. The report notes that the treatment for spiny naiad appeared to have been successful.
Treating Foster's Pond for fanwort, and Dug Pond for Brazilian elodea, could cost upwards of $50,000. The Foster's Pond Corporation has been collecting contributions from area residents in preparation for just such an effort over the last few years. The Board of Directors will consider the ACT recommendations and decide how to proceed. If the recommendations are adopted, the Corporation will seek approval from the Andover Conservation Commission, which can authorize weed treatments under an ongoing Order of Conditions that governs the Corporation's stewardship of the Pond.
Two Areas of Pond Receive Diquat Treatment
July, 2010
Two areas of Foster's Pond were sprayed with an herbicide on July 19, in an effort to eradicate a potentially troublesome invasive weed that was discovered in the Pond for the first time last year.The new pest, spiny naiad, was found in the Channel and on the north shore of the Main Pond. A fast-acting contact herbicide, diquat, was applied to both infestations. Altogether, about 3.5 of the Pond's 120 acres were treated. The Pond was closed to fishing, boating, and swimming for the day, and residents living near the treatment areas were advised not to use Pond water for irrigation for the next five days.
July 19: Technicians spray diquat in the Channel, in an effort to control spiny naiad. A small section of the Main Pond was also treated. The mid-day spraying operation took less than two hours, as a pair of technicians from the Corporation's lake management consultant, Aquatic Control Technology, passed back and forth in the treatment areas in a motorboat, using a GPS device to track their progress.
The herbicide, diquat, is said to the most commonly used aquatic weed-killer in Massachusetts. It is sold under the brand name Reward.
Two areas of the Pond, marked in red, were treated with diquat on July 19. ACT senior biologist Marc Bellaud, who oversaw the operation, said he expected that the target species in the treatment zones will begin to die off in about a week, and be pretty much gone in about two weeks. The diquat is also expected to kill ribbonleaf pondweed, a native plant which has covered several patches in the Channel due to the low water level in the Pond.
The diquat will not, however, kill fanwort, which has returned in force this year after having been largely beaten down by a weed treatment administered in 2005. Fanwort had before that treatment become the dominant weed in the Pond. The Corporation is planning another whole-lake treatment next year aimed at the fanwort, but that will require the use of a different herbicide, Sonar (fluridone).
Diquat Treatment Set for July 19, Closing Pond and Limiting Irrigation
July, 2010
A chemical herbicide will be applied to two areas of the Pond - one in the Channel and another on the northerly shore of the Main Pond - on July 19. As a precaution, the Pond will be closed to fishing, boating, and swimming for the day, and residents along the shorelines abutting the treated areas are cautioned not to use Pond water for irrigation until July 25.
July 19: Pond will be closed for one day. Water from treatment areas should not be used for five days. Click on poster to see full-sized image. A total of approximately 3.5 of the Pond's 120 acres will be treated in an effort to keep a newly-discovered invasive weed, spiny naiad, from spreading. The non-native invader, first discovered in an inspection last year, is capable of producing millions of seeds and taking over a pond ecosystem.
Licensed applicators from the Corporation's lake management consultant, Aquatic Control Technology, will spray the herbicide from a small boat in the areas where spiny naiad has been found. They will be using diquat (sold under the brand name Reward), said to be the most widely used aquatic herbicide in Massachusetts. The spraying plan was approved earlier this year by the Andover Conservation Commission, and a license for next week's treatment has been issued by the State Department of Environmental Protection.
Warning posters will be put up in various locations with access to the Pond, closing the Pond for boating, fishing and swimming on July 19. The closure does not apply to Dug Pond or the Mill Reservoir, which will not be affected by the treatment. The posters also warn that Pond water within 200 feet of the treatment areas should not be used for drinking, cooking, livestock watering, or irrigation until July 25.
Two areas of the Pond, totaling about 3.5 acres, are slated for treatment with diquat on July 19. The chemical will be applied from a small boat. Diquat binds to sediments, which render the chemical biologically inert. That is one reason the chemical may be used near shallow wells. Nevertheless, owners of shallow wells near the treatment areas have been cautioned to use bottled water, or water that has passed through a charcoal filter, if they want to feel absolutely secure.
No one gets their drinking water directly from the Pond, but some residents use Pond water for irrigating lawns or gardens, and they are cautioned not to use water in the treatment areas for five days - or they may find their lawns going the way of the spiny naiad.
Diquat will also reduce some other weeds in the treatment areas, including ribbonleaf pondweed which has prospered in the unusually low water level this Summer. Diquat will not, however, have much effect on fanwort, the long-term non-native weed which once dominated the Pond and has returned in thick colonies this year. A treatment of the entire Pond next year with another herbicide, Sonar, will be needed to get rid of fanwort.
Inspection Finds Spiny Naiad and Fanwort
July, 2010
As the thermometer hovered at 100 degrees, biologist Marc Bellaud rowed the shoreline of Foster's Pond, occasionally reaching deep into the water to grab a handful of weeds.What he found was no surprise. Fanwort has spread in shallow waters throughout the Pond, and a newer invader - spiny naiad - has established a toehold in a couple of acres of the Channel.
July 6: ACT senior biologist Marc Bellaud collects weed samples from the Channel. Most of the floating weeds in the background are ribbonleaf pondweed, a native plant that expanded this year due to low water levels in the Pond. Spot treatment for spiny naiad this year, and Sonar treatment of the whole Pond next year for fanwort, will also reduce the ribbonleaf pondweed.
Bellaud, who is senior biologist for the Corporation's long-time lake management consultant Aquatic Control Technology, has been surveying weeds in Foster's Pond since 2004, and has systematically assessed the effects of weed treatments that were begun in 2005.Accompanied by FPC President Steve Cotton, Bellaud on July 6 maneuvered a rowboat into the two shoreline areas where spiny naiad was detected last year. And he rowed around much of the Pond, to determine which areas should be treated with an herbicide. Under a plan approved this Spring by the Andover Conservation Commission, the Corporation will spot-treat areas of naiad infestation before the unwanted annual can drop millions of seeds that would sprout next year.
Not much spiny naiad was visible in the Main Pond, but significant stands were evident in the Channel, mixed in with fanwort and a lot of native plants, including coontail and ribbonleaf pondweed.
Bellaud noted that the ribbonleaf pondweed appears to have expanded in a few spots in the Channel as a result of the low water level in the Pond, occasioned by work to repair the dam.
Bellaud collected samples to confirm the identification of target species back in his lab.
In accordance with this year's treatment plan, Bellaud will
prepare a map showing the areas that will be spot-treated with diquat, a fast-acting contact herbicide which will kill not only the spiny naiad but also ribbonleaf pondweed.
Spot treatments to reduce spiny naiad are now slated for July 19. The Pond will be closed for fishing, boating and swimming for the day. The tentative date for the diquat treatments - expected to cover three to five acres of the 120-acre Pond - is July 19. The Pond will be posted as closed to fishing, boating, and swimming for the day. Treated water should not be used for drinking, watering animals, or irrigation for five days following treatment.
Diquat binds to sediments, and so does not travel thought soils. That's why it can be used in areas with shallow drinking water wells. It is probably the most widely used aquatic herbicide in Massachusetts, and has been used at three other ponds in Andover, including Pomp's Pond, where the Town maintains a public beach.
Next year, the Corporation will treat the entire Pond with Sonar (fluridone), the only herbicide licensed in Massachusetts which is effective against fanwort. Sonar will also sharply reduce water lilies, ribbonleaf pondweed, and any remaining spiny naiad.
Conservation Commission Approves Diquat Plan
March, 2010
The Andover Conservation Commission unanimously approved a plan prepared by the Foster's Pond Corporation's lake management consultant to treat portions of the Pond this Summer in an effort to kill newly-discovered colonies of spiny naiad.The Commission's vote came at a meeting March 17, following presentations by FPC President Steve Cotton and Marc Bellaud, senior biologist for Aquatic Control Technology. Bellaud had prepared the treatment plan, which calls for the use of diquat on two colonies of the non-native weed, which was found during a survey of the Pond's aquatic vegetation last Summer.
Under the plan, ACT will inspect the Pond in late June, when the fast-spreading annual begins to grow. Infestations will be treated with low doses of the fast-acting herbicide shortly after the locations are verified. The aim is to kill the plants before they drop their seeds. If not controlled, the weed has the potential to take over the Pond, driving out native species.
Consultant Submits Diquat Treatment Plan
February, 2010
Aquatic Control Technology, the Foster's Pond Corporation's long-time lake management consultant, has prepared a plan to employ low doses of a widely-used herbicide to treat infestations of spiny naiad this year.Spiny naiad is a non-native invasive weed which was discovered in the Pond for the first time last Summer. It is an annual which drops millions of seeds each year, from which new plants grow the following season. If not controlled, it could take over the Pond, much as fanwort did in past years.
Under the plan developed by ACT senior biologist Marc Bellaud, two infestations - one in the Channel and another in the Main Pond - would be spot-treated with diquat, a contact herbicide which Bellaud described as "probably the most widely used aquatic herbicide in Massachusetts and other Northeastern States."
While diquat (which is marketed under the trade name Reward) has not been used previously in Foster's Pond, it has been
employed in three other Andover water bodies, including Pomp's Pond, where the Town maintains a public beach. Because diquat does not migrate through soil, and has a half life of only 1 to 2 days, it is allowed in water bodies that are close to drinking water wells. There are a handful of shallow wells still in use around Foster's Pond, though only a couple are anywhere near the spiny naiad infestations that would be treated.
Spiny naiad, which drops millions of seeds each year, could take over the Pond if not treated, according to experts advising the Corporation. Diquat is usually applied at a rate of 1 gallon per acre in water averaging four feet deep, resulting in a concentration of 0.1 parts per million. The chemical is quickly absorbed by plants. What isn't absorbed by the targeted vegetation sinks to the bottom and binds to sediments, becoming "biologically unavailable" to other organisms, according to Bellaud.
In Foster's Pond, the chemical will not spread far from the anticipated treatment areas, which together total about 5 acres. The Pond is 120 acres. Although there are no restrictions on swimming, boating or fishing on the product label prescribed by the Environmental Protection Agency, the Pond will be closed to these activities on the day of treatment, under the proposed plan.
Treated water should not be used for drinking or cooking for 3 days, irrigating turf or food crops for 5 days, or watering livestock for 1 day. None of these restrictions has much application in Foster's Pond, but they will be posted around the Pond on the day of treatment.
The ACT plan was developed in consultation with FPC Board members Amy Janovsky and David Adilman, who were asked by the FPC Board to look more closely at the use of diquat before the Board determines to go ahead with any treatment. Although diquat use in Foster's Pond has been authorized by an Order of Conditions approved by the Andover Conservation Commission in December, the Commission must still sign off on the treatment plan before diquat can be employed this year.
Spiny naiad starts to grow in June, so a mid-June inspection of the Pond will be needed to verify the locations to be treated. The treatment must be undertaken in the following couple of weeks, before the plants mature and drop their seeds.
FPC Board Moves Cautiously on Spiny Naiad Threat
February, 2010
The Foster's Pond Corporation's Board of Directors has voted to proceed cautiously with herbicidal treatment of spiny naiad, a non-native invasive weed first observed in the Pond last Summer.
The August, 2009, weed survey detected a new invasive, spiny naiad, in the two areas shown in yellow. Click the image to view a larger map. Meeting in January, the Board voted to move forward with securing permits to apply diquat to approximately five acres of the Pond - the course of action recommended by the consultant who performed a comprehensive survey of the Pond's vegetation in August. But the Board held off making a final decision on whether to make use of the permit, while it gathers more information on diquat.
Diquat (which is marketed under the trade name Reward) is one of the oldest and most widely-used herbicides approved by State regulators for use in lakes and ponds, and is approved for use in reservoirs which feed public water systems. It has previously been used in Pomps Pond, where Andover has its Town beach. However, since the chemical has not been used before in Foster's Pond, the FPC Board decided to look more closely before committing to spot-treat two colonies of spiny naiad.
The Board designated two of its members - Amy Janovsky and Weed Committee Chair David Adilman - to investigate further. They were to interview Bob Hartzel, the independent consultant from Geosyntec who detected the spiny naiad and recommended using diquat, as well as Marc Bellaud, senior biologist at Aquatic Control Technology, the FPC's lake management consultant who would apply the chemical if the FPC decides to proceed with a treatment. Amy is also undertaking her own review of scientific literature on diquat.
Spiny (or European) Naiad is a hardy weed with narrow 1-inch long lime-green leaves which are brittle and curved. As noted in Hartzel's report to the Corporation last October, "This invasive plant has the potential to grow densely in
shallow areas and can create monoculture stands that out-compete native species." Hartzel found stands of spiny naiad in the Channel and in on the northwest shore of the Main Pond. He recommended that the Corporation arrange for spot-treating these infestations with diquat in 2010.
Spiny naiad, also known as European naiad, was discovered in Foster's Pond in August. The FPC's consultant has recommended treating the two infestations with diquat in 2010. According to ACT biologist Bellaud, spiny naiad is an annual. It drops seeds - by the millions - which sprout the following year. The strategy for eradicating it is to kill young plants with an herbicide before they can produce seeds. One problem: Seeds which fail to sprout one year can survive in lake-bottom sediments and sprout the next year - or the next - so that successive treatments may be needed to beat back the weed.
Until now, the main threat to the Pond's health has come from fanwort, an invasive weed that became the dominant plant in much of the Pond until the Corporation stepped in with Sonar, a different herbicide which is the only effective way to counteract fanwort. Sonar treatments had spectacular results, virtually eliminating fanwort for several years while allowing native plant species to rebound.
But, as expected, the fanwort has returned, and another whole-lake Sonar treatment is likely to be needed, perhaps in 2011. A major worry now that spiny naiad has appeared is that the next Sonar treatment will clear the way for spiny naiad seeds to sprout with no competition - allowing the new invader to take over the Pond. A 2010 diquat treatment of today's relatively small spiny naiad infestations would block new seed production, so that the only seeds that would sprout in 2011 would be those left over from last year. Sonar treatment in 2011 would take out spiny naiad growing from the left-over seeds, along with the fanwort, giving native plants the upper hand. Neither Sonar nor diquat kills the seeds.
As the FPC Board continues its study of diquat, the Corporation will seek approval from the Andover Conservation Commission for using the chemical this year. The Commission has already voted to approve a three-year Order of Conditions which allows diquat use in Foster's Pond, but must give its okay to a specific treatment plan before the herbicide can be utilized.
The Board has invited ACT biologist Bellaud to the Corporation's Annual Meeting on April 12 to explain the treatment program and answer questions.
Conservation Commission Extends Lake Management Program
December, 2009
The Andover Conservation Commission has extended, through 2012, its approval of the lake management program under which the Foster's Pond Corporation conducts periodic weed treatments and annual winter drawdowns.The Commission voted unanimously on December 1 to keep in place an Order of Conditions that covers hydro-raking, treating the Pond with Sonar to control fanwort, drawing down the water level every winter, maintaining the Foster's Pond Dam, and educating residents and visitors on watershed management practices. The Order was amended to allow the use of another herbicide, diquat, to control a newly-discovered invasive weed, spiny naiad.
The Order of Conditions is the Commission's detailed directive for regulating the management of Foster's Pond. It dates from 1992, when the Commission first authorized the use of hydro-raking to control nuisance weeds and remove muck from shoreline areas. In 2005, after extensive public hearings, the original Order was extended through 2009 and expanded to put in place a wide-ranging program that included herbicide treatment to eradicate non-native weeds such as fanwort. The Foster's Pond Corporation was designated as responsible for implementing the program.
With the 2005 Order scheduled to expire on January 4, 2010, the Commission voted this month to keep the program in place for another three years, the maximum presently allowed by State regulations.
The vote approved the recommendation of FPC President Steve Cotton, who briefly addressed the Commission and thanked members for their long-standing support of efforts to protect and preserve Foster's Pond.
The inclusion of diquat in the arsenal of weed treatments permitted under the Order opens the way for a 2010 spot-treatment
of spiny naiad, detected for the first time last August during a comprehensive survey of aquatic vegetation in Foster's Pond conducted by Geosyntec.
The August, 2009, weed survey detected a new invasive, spiny naiad, in the two areas shown in yellow. Click the image to view a larger map. While the survey also documented the re-emergence of fanwort, Geosyntec recommended that the FPC limit treatment efforts in 2010 to the spiny naiad and delay considering a whole-lake assault on fanwort until 2011. A preliminary cost estimate of the diquat treatment is approximately $4,000; a fanwort treatment of the entire Pond is expected to cost more than ten times that amount.
The FPC Board of Directors has not yet made a decision on whether to treat the spiny naiad in 2010. And before any treatment can be undertaken in 2010, the Conservation Commission must sign off on a schedule and treatment program for the year.
Diquat is marketed under the trade name "Reward." According to Marc Bellaud, senior biologist for Aquatic Control Technology - the FPC's long-time lake management consultant - dquat is a "widely used contact herbicide" that "is applied to lakes and ponds throughout North America to control nuisance submersed aquatic plants." While effective for control of spiny naiad and some other invasive weeds, diquat does not kill fanwort. Among the herbicides permitted in Massachusetts, only Sonar works on fanwort.
Diquat is typically applied in late June or early July, within two weeks of the time that the spiny naiad starts growing. Spiny naiad is an annual that develops from seeds each year.
Although the product label prescribes no restrictions on swimming, fishing, or other recreational activities in treated water, ACT recommends the following temporary water use restrictions for diquat: no boating, fishing or swimming in the treated water on the day of treatment, and no use of treated water for drinking, watering livestock or irrigation for five days.
Based on the extent of spiny naiad observed by Geosyntec in August, it is estimated that approximately 5 acres of the 120-acre Pond would require treatment. Spiny naiad was found in the Channel and at one location along the northeasterly shore of the Main Pond.
2009 Survey Finds More Fanwort and Discovers Spiny Naiad
October, 2009
Four years after the entire Pond was treated with herbicide, and two years after a "spot" treatment was applied to the Channel, fanwort - the invasive weed which had become the dominant plant in most of the Pond - has begun to re-establish itself.Pond residents were reporting fanwort sightings throughout the Summer of 2009, and their observations were confirmed by a systematic study conducted by Geosyntec, an environmental consulting firm retained by the Foster's Pond Corporation.
On August 27, Geosyntec Senior Water Resources Scientist Bob Hartzel took vegetation samples at 50 locations, pulling up
plants with a grappling hook to identify submerged species. The samples were taken from the same locations that FPC consultants have inspected in previous studies.
This vegetation map, from Geosyntec's report, shows areas of moderate to dense weed growth. Most of the vegetation is native, but the red dots depict locations where fanwort was found. (The four red triangles are water sampling locations.) Click the image to view an enlargement. "Fanwort was present at over half of the sampling stations and was distributed throughout the pond, compared to 2008 when Fanwort was observed at less than 10% of the sampling stations," Hartzel wrote in his 11-page report, which was provided to the Corporation on October 15.
Hartzel warned that "recent history clearly indicates that the conditions in Foster's Pond are well suited for dense growth of Fanwort over much of the pond's littoral zone (area of rooted plant growth). As such, the widespread nuisance Fanwort growth that characterized Foster's Pond prior to the 2005 Sonar herbicide treatment appears likely to recur over the next several years if additional herbicide applications are not conducted."
But Hartzel suggested that the Corporation refrain from treating the Pond in 2010. "Given that Fanwort was either absent or growing in very low densities (<5%) at a vast majority (78%) of the sampling stations, Geosyntec recommends that summer 2010 whole-lake Sonar treatment is not warranted at this time," he wrote in his report. "Given the wide distribution of Fanwort around the lake, spot treatment is not warranted at this time."
Hartzel further noted in his report, "It is encouraging that the whole-lake Sonar treatment in 2005 (and follow-up 2007 spot treatment) has yielded such a high degree of Fanwort control over a four-year period."
In a telephone conversation with FPC President Steve Cotton following submission of the Geosyntec report, Hartzel urged the Corporation to "be a little on the conservative side" in considering when to treat the Pond with Sonar again. He suggested that holding off on Sonar treatment for another year would be beneficial for the health of the Pond, as well as more economical for Pond residents. He also said that he would be "surprised" if the Pond did not need a Sonar treatment in 2011.
Hartzel's survey also detected a new invader, Spiny (or European) Naiad, a hardy weed with narrow 1-inch long lime-green leaves which are brittle and curved. As noted in Hartzel's report, "This invasive plant has the potential to grow densely in
shallow areas and can create monoculture stands that outcompete native species." Hartzel found stands of spiny naiad in the Channel and in one location on the northwest shore of the Main Pond. He recommended that the Corporation arrange for spot-treating these infestations in 2010 with diquat.
Spiny naiad, also known as European naiad, was discovered in Foster's Pond in August. The FPC's consultant has recommended treating the two infestations with diquat in 2010. Hartzel also found a third invasive, Brazilian elodea, persisting in Dug Pond. This aquarium plant, which had been detected in prior surveys, has the potential to become a problem. Hartzel reported that the Dug Pond infestation "may be the only known occurrence of Brazilian Elodea in Essex County," and indicated that the State may be interested in trying to eradicate it before it spreads further.
Hartzel is the former Lakes and Ponds Program Coordinator at the Massachusetts Department of Conservation and Recreation. David Adilman, a member of the FPC Board of Directors and Chairman of the FPC's Weed Committee, arranged for Hartzel to conduct this year's survey at the request of the FPC. Adilman is a senior hydrogeologist at Geosyntec.
Weed Survey Shows Sharp Decline in Fanwort After Treatments
December, 2008
Back in 2004, when the Foster's Pond Corporation commissioned a comprehensive survey of vegetation in the Pond, the results were appalling: 79 per cent of the Pond was covered by plants of some type, and by far the most abundant was fanwort - a non-native, water-clogging invasive weed that covered more than half the surface. Virtually anywhere you stuck a pitchfork into the Pond, you'd come up with a clump of the stuff.That's all changed. This year, after herbicidal treatments in 2005 and 2007, the Corporation contracted for a follow-up survey, and the results, contained in a just-completed 13-page report, are pretty close to miraculous: plant cover has shrunk to just under 16 per cent (that's only one-fifth of the area that was covered by weeds in 2004), and fanwort dominated less than 1 per cent of the Pond.
2004: Pink, blue and lighter green areas are mostly fanwort. The darker green denotes water lilies. Black is open water. (Dug Pond wasn't surveyed in '04). 2008: The greenish areas denote water lilies. The blue is open water. That little spot of pink is the only significant colony of fanwort. (Click the images for larger maps.) In 2004, fanwort was everywhere. At 39 locations in the Pond, a biologist dragged the bottom and analyzed the plants; fanwort was the prevalent species in 35 locations. In 2008, using a portable GPS unit, the biologist returned to the exact same locations, plus 10 new ones. Fanwort turned up at only 3 locations (4 if you count the one where a fragment was spotted floating in the water).
Only one spot had a thick colony of fanwort - the mouth of the Mill Reservoir. Although this spot was treated both in 2005 and 2007, it's a narrow channel through which all the water entering Mill Reservoir from Frye's Brook, and from springs which feed Dug Pond, flow into the main water body. One effect may have been to flush away the herbicide, letting deeply-buried root balls of the fanwort survive just in this area.
Marc Bellaud, senior biologist at Aquatic Control Technology, Inc., conducted both surveys for the Corporation, and
oversaw the weed treatments as well. He concluded that there is not enough fanwort in Foster's Pond to warrant treatment in 2009.
2005: Fanwort in the Main Pond prior to treatment Both surveys were conducted at nearly the exact same time of the year. The 2004 survey was done on August 16, and the 2008 survey on September 2.
The survey also included water quality sampling for the Main Pond, the Mill Reservoir, the Outlet Cove (between the Channel and Rock Island), and Dug Pond. In all locations, coliform bacteria were below laboratory detection limits.
In the Mill Reservoir and Dug Pond, phosphorous was below detection limits. There was more phosphorous in both the Main Pond and the Channel - levels, said that report, that are "sufficient to support nuisance algal blooms."
And the report noted a good deal of algae suspended in the water. The good news is that the algae may have blocked enough sunlight to keep down the growth of weeds. The bad news is that algae can get out of hand, too.
The phosphorous finding underscores a lesson for all residents on the Main Pond and the Channel: don't use fertilizers containing phosphorous, and use low-phosphate detergents, even in your dishwasher.
With Fanwort Slow to Rebound, Pond Is Surprisingly Weed-Free
August, 2008
Marc Bellaud was amazed. The biologist who back in 2004 conducted the most comprehensive weed survey ever of Foster's Pond, and has combed the Pond for invasive weeds every year since, was back at it on a gorgeous September afternoon, dragging a rake again and again across the bottom, pulling it up for examination, and finding - absolutely nothing.Bellaud's four-hour canvas of the Pond took him to each of the 39 "data points" - located by GPS - at which he had recorded what aquatic plants were present in 2004. In addition, this time he collected weed data from Dug Pond, and took water quality samples in the Mill Reservoir, the Channel, Dug Pond, and the Main Pond.
In 2004, fanwort - a non-native invasive often found in home aquariums - was the most common plant in the Pond, driving out native plants and covering over half of the Pond's open water. It was then the most prevalent plant in 34 of the 39 data point locations.
What a difference some Sonar makes! Sonar is the trade name for the low-dose herbicide (fluridone) that is the only known treatment to get rid of fanwort. The Corporation contracted with Bellaud's employer - Aquatic Control Technology, Inc. - to treat Foster's Pond with Sonar in 2005. The following year, the Corporation treated near-by Dug Pond, and in 2007 re-dosed the Channel and the passage between the Main Pond and the Mill Reservoir.
Bellaud's survey this month - conducted at the same time of the year as the 2005 study - was commissioned by the
Corporation to yield a systematic view of Pond vegetation in the wake of all these treatments.
September 2, 2008: ACT senior biologist Marc Bellaud pulls up his underwater video camera, along with a clump of bladderwort, in Dug Pond. The mat of floating bladderwort next to the boat doesn't appeal to some residents, but it's a native species that most biologists regard as just part of the natural ecosystem. There were two key questions the survey was designed to answer: What are the enduring effects of these treatments, and will another treatment be needed in 2009?
The answers came up in each sample that Bellaud raked from the bottom, along with his careful observations from the surface and through an underwater video camera. He found a few pockets of fanwort concentrated in widely spread colonies - notably, the mouth of Mill Reservoir, and in two coves at opposite ends of the Main Pond - as well as isolated sprigs in various locations, but there is far too little fanwort anywhere in Foster's Pond to warrant treatment next year.
Since at least two of the fanwort colonies had been observed last fall - triggering the Corporation's concern that it would be prudent to undertake a systematic survey this year - Bellaud was astonished that the weed had not spread further. Indeed, the colonies seemed a bit smaller than they had appeared last year.
Bellaud had a theory. High water levels, coupled with algae in the water that is blocking sunlight to the bottom, may have suppressed the spread of fanwort. And last year's use of pelletized Sonar - slow-release bits of Sonar-infused clay resting on the bottom - may have prolonged the fanwort's exposure to the herbicide, completely killing the root systems and preventing fragments from re-establishing a foot-hold.
Whatever the reason, the results could not be more stark - or more welcome. To the delight of many Pond users, water lilies - which are native, and which are also susceptible to Sonar - have disappeared from much of the Channel, as well as from the passage between the Main Pond and the Mill Reservoir, leaving wide open expanses the likes of which haven't been seen in decades. In 2008, for the first time in years, shoreline property-owners in the Channel saw no reason to call in the hydro-rake. There are too few lilies to bother with.
Native species that are not considered pests have repopulated some areas of the Pond formerly dominated by fanwort.
Some residents have been put off by the appearance of large, brown floating mats in Dug Pond, but Bellaud said that they are composed of bladderwort, a native plant whose tiny "bladders" allow it to float on the surface. It is not usually regarded as a nuisance weed, and is not normally treated, though it can easily be cleared from the surface by hand raking if anyone has the energy or inclination.
Bellaud's detailed written report on the survey is expected before the end of the year.
Report: Channel Is Fanwort-Free, But Not Main Pond
December, 2007
The 2007 Sonar treatment of 18 acres of Foster's Pond left no traces of fanwort in its wake.The persistent, non-native weed - which by 2004 had become the dominant plant in the Pond - had all but vanished after the entire Pond was treated in 2005, but re-emerged by the end of 2006 in shallows from the dam through the Channel, and between the Mill Reservoir and the Main Pond.
It was those areas that the Corporation zapped in 2007, this time using a pelletized formulation of the slow-acting herbicide,
which concentrated the treatment at the roots of plants which had evidently survived the 2005 treatment. Water-impermeable barriers kept the chemical in the treatment area and out of the Main Pond, where the Sonar would have quickly been diluted and where no new fanwort had been observed. Until this year.
The 2007 treatment area (in blue) totaled 18 acres. Water-impermeable barriers (in yellow) kept the Sonar from dissipating in the Main Pond. Click on the image above for a larger view. In an October inspection that covered both the treatment area and the rest of the Pond, the Corporation's lake management contractor - Aquatic Control Technology, Inc. - found no fanwort in the northerly half of the Pond, but in several locations along the western, southern, and southeastern shorelines of the Main Pond.
ACT delivered a written report on its findings to the Corporation in December. (To read the full text, click here.) The report states, "The extent and distribution of this fanwort regrowth suggests that it is regrowing from stem and/or root tissue that was not completely controlled following the 2005 treatment."
The report identifies two five-acre areas - at each end of the Main Pond - where most of the new fanwort is growing, though the actual extent of fanwort within those areas is only an acre each. Isolated stands of fanwort were detected elsewhere along the shore, and their locations were plotted by GPS on a map included in the report.
The purple dots are GPS locations of fanwort colonies observed by ACT in October. Most of the fanwort was growing within the 5-acre areas shaded green, although the total fanwort coverage was estimated at 1 acre in each zone. Click the image above for a larger view. ACT recommended monitoring the fanwort, rather than attempting to treat it, in 2008. "Our experience treating small portions of large, open-water basins with Sonar pellets at other lakes have been largely disappointing," wrote ACT's senior biologist Marc Bellaud.
"For the 2008 season, we would recommend monitoring the fanwort growth in the Main Pond and educating FPC members, lake residents, and lake users to avoid excessive disturbance in areas of heavy fanwort growth (to the extent that is practical) to help minimize fragmentation," wrote Bellaud.
Bellaud also recommended a late-summer survey of weeds in the Pond to monitor expansion of fanwort - and see what is happening in areas treated in 2006 and 2007. The FPC's Board of Directors intends to implement this recommendation in 2008.
One possible outcome: another treatment in 2009. Whether a treatment will be needed, and where, will depend on how fast the fanwort spreads, and whether it gets back into portions of the Pond which are now fanwort-free.
Despite the persistence of the fanwort, one thing is certain. There is far less of it, and it covers far less area, than before control measures were instituted in 2005. Residents along the Channel have marveled all summer at the absence of the weeds which used to clog the area, and anglers have exulted at the areas now accessible for fishing. And the raft in the Main Pond has never, in recent memory, had a busier or more weed-free swim season.
Channel Gets 2d "Booster" Treatment
July, 2007
For the third - and most likely the final - time this summer, the roar of the airboat reverberated across the Pond, as technicians applied another dose of Sonar herbicide to nuisance vegetation in an 18-acre treatment area.
July 27: Marc Bellaud, senior biologist from Aquatic Control Technology, guides the airboat past the dam. It took about an hour for the powerful craft to zoom in and out of coves from the dam to the two temporary barriers near the Main Pond that were put in place earlier this year to keep the chemical from dissipating into the larger basin.
As the boat followed its winding route, a spreader on the bow broadcast tiny herbicide-infused clay pellets - about the size of a grain of rice - into the water. As the pellets break down, they release the chemical. The idea is to maintain a steady concentration of the slow-acting herbicide.
The treatment is showing dramatic results. The primary target, fanwort, would have clogged the Channel with bright green
mats by now; instead, the stunted plants are visible a foot below the surface, their tips a sickly pale color, and stems already beginning to decay. Water lilies have almost vanished from much of the treatment area, leaving vast expanses of open water. The native lilies, however, are expected to rebound.
July 27: Nuisance weeds, including lilies, have nearly vanished from the channel between the Main Pond and the Mill Reservoir. Weed Treatment Is Working Wonders
July, 2007
If you live on the Channel, or have been fishing from the dam, you already know this. This year's weed treatment has reduced nuisance weeds to barely-noticeable stands of sickly stubble, leaving the 18-acre treatment area astonishingly clear.
July 15: Lilies in the treatment area showing signs of "chlorosis." Although they're not the target of the weed treatment, residents are delighted that dense stands are thinning out, even if the effect will be temporary. Fanwort, which is the Pond's most dangerous invader, would have exploded by now into impenetrable mats clogging much of the Channel - a condition with which residents and visiting anglers were all too familiar before the 2005 treatment of the entire Pond. That treatment virtually eliminated the non-native weed, but significant stands began to re-emerge late last summer.
This year's partial-lake treatment, designed to beat back the weeds before they could take over the entire Pond again, has left them reeling. Sonar, the slow-acting herbicide used in the treatment, renders the plants vulnerable to a process called "chlorosis" - bleaching of their chlorophyll, leaving the plants unable to produce nutrients. Now, a foot or more beneath the surface, it is possible to see hundreds of fanwort plants, their normally bright-green tips a sickly shade of pale, their remaining leaves brown and dying.
Pond lilies, too, are taking a hit - much to the delight of residents who prefer the lilies in lesser densities. The lilies, which are native, will rebound after the treatment, as will other indigenous plants.
Fanwort Shows Signs of Fading
June, 2007
We may not know what happened to Tony Soprano, but the handwriting is on the wall for fanwort in the Channel.A little more than three weeks after treating 18 acres of the Pond with a slow-acting herbicide, Aquatic Control Technology's senior biologist Marc Bellaud pointed to the tell-tale signs that the nuisance weeds are beginning to succumb. The tips of the
feathery plants, normally bright green in healthy specimens, are starting to bleach out to a pinkish white.
June 25: Fanwort near the dam begins to show signs of "chlorosis." The tips have started to bleach out as a result of the herbicide treatment. Bellaud and an assistant were back on the Pond June 25 to administer a second dose of the herbicide. The initial treatment was applied June 1.
Fanwort is a non-native aquatic weed that had become the dominant plant in the Pond until the Foster's Pond Corporation had the entire 120-acre water body treated two years ago. Some of the oldest plants, with their basketball-sized root structures, apparently survived that assault, and this year the Corporation is treating only the areas where the fanwort came back.
ACT, the Corporation's lake management consultant, uses fluridone (sold under the brand name Sonar) to kill fanwort. That is the only effective method allowed by environmental authorities in Massachusetts. It is also the least toxic aquatic herbicide that is permitted in the State's lakes and ponds. Sonar does not migrate through soil, does not bioaccumulate in wildlife, and has a short half-life. At the concentrations employed in Foster's Pond, it is allowed in the State's public drinking water reservoirs right up to the intake pipe.
June 25: The airboat makes the turn at the Foster's Pond Dam. The red spreader at the bow is dispersing Sonar-infused pellets, while hoses trailing along the side are infusing liquid Sonar into the water. Sonar works by blocking the plant's production of yellow pigments which protect chlorophyll from breaking down in sunlight. Without the yellow pigments, the chlorophyll bleaches out, the plant can't produce the food it needs, and it dies. The process is called "chlorosis," and it takes at least 6 to 8 weeks to kill the plant. Biologists regard the slowness of the process as a good thing, since a more rapid die-off would run the risk of depleting oxygen in the Pond.
Fanwort is particularly susceptible to the low concentrations - 10 to 20 parts per billion - used for the weed treatment. Native plants are hardier, although they do thin out as a result of the treatment. The effects are quite noticeable on the Pond's lilies, though many residents welcome a reduction in lily density. The lilies rebound in a year or two.
June 25: Two barriers have been set to keep Sonar in the treatment area. At this barrier, between the Main Pond and the channel leading to Mill Reservoir, the herbicide is starting to trigger chlorosis in lilies within in the treated area, while those outside the target zone remain bright green. The June 25 "booster" treatment once again made use of one of ACT's airboats. Two formulations of Sonar were used in the booster treatment. Sonar-infused clay pellets were broadcast from a bow-mounted spreader, while liquid Sonar was pumped directly into the water through submerged hoses trailing from either side of the fast-moving craft. The liquid Sonar was used to quickly restore the Pond's herbicide concentration to the level lethal for fanwort, while the pellets will exude Sonar slowly over a longer period, maintaining the concentration at a steady level.
Before the operation began, the Pond was posted to keep swimmers, boaters, and anglers out of harm's way while the airboat was maneuvering around the treatment area.
The water will be tested in about three weeks to see whether the necessary concentration remains in the Pond. That will be dependent on weather conditions, which can affect both outflow of the chemical and how rapidly it breaks down. Another booster treatment may be needed next month.
First "Booster" Treatment Scheduled for June 25
June, 2007
The airboat will return to the Pond June 25 to administer a second dose of Sonar to the 18-acre section targeted for weed treatment this year.The treated portions of the Pond will be closed to fishing, boating and swimming for the day. The closure is a safety precaution to give the fast-moving craft plenty of room to maneuver in the Pond's narrow coves.
The Pond received its initial treatment on June 1. The June 25 "booster" is the first of two or possibly three repeat treatments aimed at keeping the herbicide concentration high enough to kill fanwort, the non-native weed which once dominated the Pond. Sonar is the brand name of the herbicide (fluridone) being used in the treatment.
Weed Treatment is a (Noisy) Breeze
June, 2007
Treating 18 acres of Foster's Pond with herbicide is a breeze - if you happen to have an airboat. It took little more than half an hour on June 1 for technicians to spray tiny clay pellets over about 15 per cent of the Pond targeted for treatment by the Foster's Pond Corporation this year.
June 1: Airboat, with red cyclone spreader at the bow, skims over the Main Pond on its way to the treatment area. First, however, they had to wrestle a pair of temporary "limno-barriers" into place. The cloth barriers, anchored to the bottom with concrete blocks and held up by bright yellow flotation collars, are needed to keep the herbicide from dissipating into the Main Pond. One barrier blocks the channel from the Main Pond to Mill Reservoir; the other, which has a small gap at one end to allow boats to pass freely, extends across the passage from the Channel to the Main Pond.
It took two hours in muggy near-90 temperatures under a blazing sun to get the barriers in place. The rest of the job was easy.
Sporting a bow-mounted spreader to distribute thousands of tiny, herbicide-laden pellets, the airboat - the same kind that is a common sight in the Everglades - careened noisily down the Channel and around Rock Island, then circled past the dam. Those on board wear earmuffs to drown the sound. The roar never fails to bring residents down to the shore for the rare spectacle of such a powerful craft churning up a cloud of spray in its wake.
ACT technicians begin to stretch a "limno-barrier" across the passage between the Main Pond and the Mill Reservoir. The temporary barrier is intended to keep the herbicide concentrated in the treated passage. The target of all this commotion is fanwort, a nonnative invasive weed which practically took over the Pond until a 2005 herbicidal treatment nearly eradicated it. Adjacent "Dug Pond" was treated last year, and the entire watershed remained almost fanwort-free until late last summer. That's when pockets of the persistent nuisance were observed by the Corporation's volunteer "weed-watchers."
Barrier across the passage between the Mill Reservoir and the Main Pond. View is from the Main Pond, looking towards the Mill Reservoir. Goldsmith reservation is in the background. A more formal assessment in September by the Corporation's lake management consultant, Aquatic Control Technology, picked up the presence of fanwort in much of the outlet cove (near the dam), the Channel, and the passage between the Mill Reservoir and the Main Pond. No fanwort was found in either the Mill Reservoir or the Main Pond, and the decision was made to undertake a "spot treatment" this year, hitting just the areas where the fanwort had survived from the 2005 effort. ACT experts theorized that the surviving plants were the oldest in the Pond, and their basketball-sized root structures had likely not been completely killed by the 2005 treatment.
This year's treatment is using the same herbicide - fluridone, which is sold under the brand name Sonar - that was employed in 2005.
The slow-acting chemical is the only herbicide authorized for use in Massachusetts waters which works on fanwort. Fortunately, it is also the least toxic herbicide that can be used here against aquatic nuisance vegetation. At the concentrations approved for the Foster's Pond program - 10 to 20 parts per billion - it can be used in public water reservoirs right up to the intake pipe. It does not migrate through soils, and it does not bioaccumulate in fish or wildlife. It also has a short half-life.
Temporary barrier across the passage from the Main Pond to the Channel, as viewed from the Main Pond. Orange signs to the right mark a gap between the shore and the floatation collar, which will allow boats to pass easily. But instead of using only liquid Sonar, as in 2005, the formulation used this year will consist mostly of Sonar-infused clay pellets. They sink to the bottom and dissolve slowly, so a higher concentration is delivered to the fanwort at its roots. The aim is to get the plants to absorb more of the herbicide so that the entire root structures die.
Approaching the temporary barrier from the Channel, the gap is on the left. Canoes, kayaks, and bass boats should have no problem getting through - at least, under current conditions. Sonar works by blocking the plants' production of yellow pigments which protect chlorophyll from breaking down under sunlight. Without the yellow pigments, the plants slowly bleach out and die. The process (called "chlorosis") can take upwards of 6 to 8 weeks - an advantage, since the slow dying avoids the prospect of sudden oxygen depletion (which could result in fish kills) or nutrient release (which could result in algae blooms).
Signs at each of the temporary barriers ask boaters to pass through carefully. Please report any vandalism to the signs or the barriers to the FPC. The slowness of the process means that the effective 10 -20 ppb concentration must be maintained in the water over a period of several weeks. Since the Sonar has a short half-life (about 21 days), one or two "booster treatments" are usually needed. That means the airboat will be back on the Pond, probably by the end of June.
The flotation collars on the limno-barriers should prove to be a minor nuisance to canoers and kayakers. The gap at one end of the barrier between the Channel and the Main Pond makes the passage easy, even for a bass boat with an electric motor. The barrier between the Main Pond and the Mill Reservoir, however, takes a bit more effort. There are flattened segments, about a foot wide, every four feet or so, and these present the easiest places to surmount the obstacle. But it still takes a bit of poling to get over - and it helps to reach over both sides at once and pull the canoe or kayak across. Bass boats may find it impossible to get between the Mill Reservoir and the Main Pond until the barrier comes out in September.
Fanwort's Up; Treatment Set for June 1
May, 2007
"There's a patch," said Marc Bellaud, pointing through the Pond's clear water to a half-dozen day-glo-green shoots of fanwort two feet below the surface.
May 23: ACT Senior Biologist Marc Bellaud examines a sprig of fanwort raked from the bottom of the Channel. Bellaud, senior biologist for Aquatic Control Technology, was seated in a small motorboat, plotting locations with his hand-held GPS in the run-up to this year's first herbicidal treatment of the Pond's nuisance weeds. His conclusion: The fanwort is nearing the most vulnerable point in its growth cycle, and treatment should start.
On June 1, ACT - the Corporation's lake management consultant - will launch an airboat onto the Pond, spraying herbicide-infused clay pellets on 18 of the Pond's 120 acres. The targeted areas will be closed to fishing, boating and swimming for the day, to give the fast-moving craft unimpeded room to maneuver.
The treatment areas include the outlet cove (from the dam to Rock Island), the Channel (from Rock Island all the way to the Main Pond), and the channel between the Main Pond and Mill Reservoir.
Bellaud inspected the Pond's vegetation May 23 with FPC President Steve Cotton, focusing on these "hot spots," which had been identified last fall for treatment this summer.
Bellaud, using an underwater camera and occasionally tossing out a rake to bring up samples from the bottom, found shoots of fanwort just where he expected to, concentrated in the targeted treatment areas in the Channel and in the passage between the Main Pond and the Mill Reservoir. As had been the case last fall, none was observed within either the Mill Reservoir or the Main Pond.
Fanwort is a persistent and fast-growing invader that had become the Pond's dominant plant for decades. In 2005, the Corporation, after months of study and public hearings, treated the Pond's entire 120 acres and nearly eradicated the unwelcome guest, which had choked much of the Pond to the detriment of fishing, boating, and swimming. Left untreated, a lake can become so clogged with the stuff that fish die.
Although the Pond remained practically fanwort-free during 2005 and much of 2006, by fall of last year it had re-emerged in several areas. ACT theorized that these were stands of the oldest plants, whose basketball-sized root structures had not been completely killed by the 2005 treatment.
The use of pelletized herbicide is aimed, quite literally, at the roots of the Pond's
fanwort problem. The 2005 treatment used liquid Sonar (the brand name for fluridone, the only aquatic herbicide that can be used in Massachusetts to combat fanwort), which readily disperses through the water. Sonar, a slow-acting herbicide which renders submerged plants vulnerable to the bleaching effects of sunlight, must be maintained at concentrations of between 10 to 20 parts per billion for 60 to 90 days in order to do its job. The clay pellets, infused with Sonar, sink to the bottom and dissolve slowly, releasing the herbicide over an extended period - and close to the roots. The aim is to concentrate the Sonar as near as possible to the root balls of the hardy plants which survived the 2005 treatment.
About 18 acres - 15% of the Pond - are slated for Sonar treatment June 1. Although 3 temporary "limno-barriers" were originally planned, only the two on the left will be installed. Click the image for a larger version. Sonar is expensive. That's one reason the Corporation opted to target this year only the 18 acres where fanwort was detected. The 2005 treatment cost nearly $50,000, and this year's treatment of only 15 per cent of the pond will cost more than $16,000.
But treating only part of a pond is tricky. Sonar is not easily contained within a water body. ACT will install temporary barriers at two points - where treated channels meet the Main Pond - in an effort to keep the Sonar from dissipating into the much larger basin where it is not needed. The cloth "limno-barriers" will be anchored at each end and suspended from flotation collars. Canoes and kayaks can pass over the barriers; just push the floats down on each side of the craft and paddle over them. A gap will be left at one end of the barrier spanning the passage which connects the Channel to the Main Pond; that will allow bass boats with electric motors to get through, though they may have to be poled through the reeds.
Notices of the treatment schedule were mailed May 29 to shoreline owners of property abutting the treatment areas. The notices warn that Pond water should not be used for irrigation until September 1. The reason should be obvious: spraying treated water directly onto a tender garden plant or a lawn could set in motion the same process which kills the fanwort.
At the concentration that will be used in the Pond, Sonar has been approved by State and Federal regulators for use in municipal water reservoirs right up to the intake pipe. No one draws drinking water directly from Foster's Pond, but the Corporation wanted to be sure that the minimal necessary concentration was used.
With $ Coming In, FPC Board OKs Weed Contract
May, 2007
The Foster's Pond Corporation Board has voted to proceed with a contract to treat parts of the Pond with Sonar this Spring. The vote came at an April 23 meeting, after Treasurer Dave Brown and Fundraising Committee Chairman Marty Rabinowitz reported that fundraising efforts are on track to cover the $16,150 cost of applying the herbicide.A biologist from Aquatic Control Technology, the Corporation's lake management consultant, is expected to visit the Pond later this month to determine the best time to administer the treatment. Sonar is the brand name for a chemical called fluridone, which is the only effective way of combating the fanwort, the non-native nuisance weed that had clogged the Pond for years until it was nearly eliminated by a Sonar treatment in 2005. It has come back in about 15% of the Pond, and this year's treatment program will target the affected areas.
Sonar works best when the plant begins its seasonal growth, usually in late May or early June. The treatment will employ a pelletized formulation of the herbicide. The Pond will close for swimming, boating and fishing the day of treatment, but will re-open the following day. Two or three treatments are anticipated to keep the proper concentration in the Pond.
Conservation Commission Approves '07 Sonar Plan
March, 2007
The Andover Conservation Commission has unanimously approved the Foster's Pond Corporation's plan to treat part of the Pond with Sonar this Spring.The vote came at a Conservation Commission meeting on March 6. Andover Conservation Director Bob Douglas recommended approval of the plan, which was submitted to the Commission by the Corporation on February 15. With little discussion, the Commission promptly gave its okay. The Commission has a history of supporting the Corporation's efforts to combat invasive weeds in the Pond.
The 2007 treatment plan, developed by the Corporation's lake management consultant Aquatic Control Technology, calls for
the application of fluridone - an aquatic herbicide sold under the brand name "Sonar" - to 18 acres of Foster's Pond beginning in mid-May or early June. The plan was endorsed by the Corporation's Weed Committee, approved by the Board of Directors, and presented to the Annual Meeting in January.
Most of the Pond stayed fanwort-free in 2006. About 18 acres - 15% of the Pond, where fanwort was spotted - are slated for Sonar treatment this year. Click the image for a larger version. The areas to be treated - about 15% of the Pond's 120 acres - were found late last Summer to have experienced regrowth of fanwort, the nonnative invader that had virtually taken over the Pond until the Corporation's 2005 treatment nearly eradicated it. Inspections by volunteer "weed watchers" last August, followed by a more systematic survey by ACT in September, turned up no fanwort throughout most of the Pond but extensive stands - including a few spots with dense mats - were found in limited areas. The infested areas extended from the dam through the entire Channel, as well as the channel between the Mill Reservoir and the Main Pond.
ACT's senior biologist Marc Bellaud theorized that the infested areas, which are only 3-4 feet deep with thick sediments on the bottom, had probably harbored the oldest fanwort plants, whose large root structures - clumps that can grow to the size of basketballs - had not been fully killed by the 2005 treatment.
The ACT plan, as approved by the Conservation Commission, will treat the target areas with a combination of quick-release and slow-release pellets, with liquid Sonar possibly used as a supplement. The highly-soluble Sonar is embedded in clay pellets, which dissolve over time to release the herbicide into the water. The aim is to maintain a steady concentration of the slow-acting herbicide at 10 to 20 parts per billion - high enough to be lethal to fanwort, but so low that State and Federal regulators regard it as safe for public drinking water supplies. While no one takes drinking water from Foster's Pond, the Corporation has sought to use minimal doses.
Fanwort in the Main Pond, before the 2005 Sonar treatment. Sonar is the only herbicide - indeed, the only effective control technique - approved by the State's Department of Environmental Protection for use on fanwort. It is the least toxic aquatic herbicide allowed in Massachusetts. According to information amassed by the State, it does not bioaccumulate in fish or wildlife, and does not migrate through soils. It has a short half-life - it quickly breaks down in sunlight - and so must be reinfused into the water in order to keep the concentration steady. Up to three treatments are expected during the 60 to 90 days it will take to kill the fanwort.
Sonar retards the growth of yellow pigments which protect the chlorophyll in submerged plants. Without those pigments, sunlight bleaches out the chlorophyll, and the plants die. This is a slow process - and that's a good thing, according to biologists. The slow die-off of the plants results in a lower drain on the water's oxygen than would occur if large masses of plants died suddenly.
Sonar is most effective if it is applied when fanwort is just emerging, usually around mid-May to June. ACT will inspect the Pond to determine the timing of the initial application. There is no mistaking the sprouting fanwort. It is a luminescent green, looking a bit like a test-tube brush.
Consultant Recommends '07 Treatment Plan for Fanwort
December, 2006
The Foster's Pond Corporation's lake management consultant, Aquatic Control Technology, has recommended a plan to treat part of the Pond with Sonar next Spring in an ongoing program to prevent invasive weeds from regaining a chokehold.The plan is contained in ACT's 2006 Year-End Report on the herbicide treatment of Dug Pond, the Town-owned swimming hole adjacent to Foster's Pond treated this year to get rid of fanwort and another non-native weed, Brazilian elodea. Although
ACT's post-treatment inspection of the 3.9-acre basin, which lies at the end of Glenwood Road, showed neither of the treated weeds appeared to have survived there, the news was not as good for the larger water body. A September 13 tour of Foster's Pond by ACT Senior Biologist Marc Bellaud turned up "robust fanwort growth" both "in the channel leading to Mill Reservoir and in the channel leading to the [dam]." No fanwort was found in the Mill Reservoir or in the Main Pond.
Fanwort in the Main Pond, before the 2005 Sonar treatment. Bellaud presented his findings and recommendations to a joint meeting of the FPC Weed Committee, Fundraising Committee, and Board of Directors. He noted that the return of fanwort one year after an initial Sonar treatment is highly unusual, noting that most of the regrowth was found in shallow areas with thick bottom sediments. "The most logical explanation for regrowth in these areas is [that] they harbored the most mature fanwort plants prior to treatment and the herbicide treatment could not completely exhaust the starch reserves in their extensive root structures." Mature fanwort plants, he told the FPC group, have "amazingly large root balls," holding his hands as if he were cradling a basketball.
The proposed plan calls for treating about half the Pond with time-release Sonar pellets, which sink to the bottom and release the herbicide over a period of several weeks. The dosage is calculated to achieve the same concentration as the 2005 treatment of the entire Pond - 10 to 20 ppb, a level which is lethal to fanwort but is approved even for use in public water supplies. The treated areas would be closed to swimming, boating and fishing on the day of treatment, but would be re-opened the following day. Three treatments would likely be needed. Bellaud proposed placing two or three impermeable "limnobarriers" - weighted fabrics suspended from flotation collars stretched across channels leading to Mill Reservoir and the Main Pond - to minimize dilution of Sonar in the treatment area. The barriers allow easy passage of canoes and kayaks.
Cost of the proposed treatment would be $16,150, about 38% of what it cost to treat the entire Pond in 2005. Under the proposal, about half the Pond would undergo treatment in 2007.
BEFORE: Fanwort in the channel, August 16, 2004
AFTER: Same location, August 5, 2005, following Sonar treatment
Prior to the 2005 Sonar treatment, fanwort had become the dominant plant in the Pond, even though it is not native to Massachusetts. It choked most of the Pond, leaving many areas unfit for swimming, fishing, or paddling. It has no natural enemies in the Northeast, and there is only one abatement method for large stands of it that is approved for use by State regulatory authorities - Sonar, a slow-acting herbicide which does not bioaccumulate in fish or wildlife and has proven less lethal on native plant species. The 2005 treatment left no detectable fanwort in the Pond that year, and left much of the Pond fanwort-free in 2006.
Final Report: Sonar KO'd "Dug Pond" Fanwort
November, 2006
Aquatic Control Technology has handed in its year-end report on the Foster Pond Corporation's 2006 weed management program. The conclusion: Sonar treatment of "Dug Pond" this summer was a success, leaving "no viable fanwort or Brazilian elodea" in the 3.9-acre swimming hole.The four-page report, prepared by ACT senior biologist Marc Bellaud, was distributed at a joint meeting of the FPC's Weed Committee, Fundraising Committee, and Board of Directors on November 29. Bellaud was on hand to outline the findings and answer questions.
Dug Pond, which is owned by the Town of Andover, is separated from Foster's Pond by a narrow berm, and flows into the
larger water body. The FPC took on task of treating Dug Pond in order to eradicate the two non-native invasive weeds that had been found growing there. While Foster's Pond has been plagued by fanwort, Brazilian elodea was a new and potentially pesky nuisance.
Dug Pond gets its first Sonar treatment June 5. ACT reported that three weeks after the initial treatment of Dug Pond in June, "both the fanwort and Brazilian elodea were showing strong evidence of chlorosis (whitening symptomatic of Sonar exposure)." A second treatment was performed on June 29. By early August, says the report, "both plants were nearly completely chlorotic." On September 13, when ACT did its final inspection, "no viable fanwort or Brazilian elodea were found in the Basin and the majority of these plants were decomposing on the pond bottom."
Fanwort from Dug Pond June 19, showing signs of chlorosis. On untreated plants, the white tips would be bright green. The report indicates that white water lilies growing by the shoreline of Dug Pond were thinned by the herbicidal treatment but are expected to rebound in 2007. Other native plant species, including bladderwort and emergent pickerelweed and rushes, remained healthy, according to the report. The report states, "No adverse impact to fish or wildlife were observed following treatment."
Bellaud's report also discusses the re-emergence of fanwort in Foster's Pond, recommending that the Corporation undertake a partial-lake treatment of affected areas in 2007. The Board of Directors and the two committees will reconvene later this month to discuss this recommendation in advance of the Corporation's Annual Meeting on January 16.
Biologist: "Dug Pond" Treatment Is Complete
August, 2006
After reviewing the latest lab results and field reports, Aquatic Control Technology's senior biologist has determined that no further treatment is needed to kill fanwort in "Dug Pond".Marc Bellaud informed FPC President Steve Cotton of his conclusion after consulting with field technicians who had inspected the 3.9-acre swimming hole on August 2 and found neither fanwort nor Brazilian elodea, the two nuisance weeds targeted by this year's Sonar treatment. The technicians also took a water sample to test the concentration of herbicide remaining in the basin, which is separated from Foster's Pond by a narrow berm.
Laboratory tests showed the Sonar concentration at 15 parts per billion - exactly midway in the target range of 10 to 20 ppb. A concentration of 10 ppb is adequate to kill fanwort; 20 ppb is the maximum allowable under the permit authorizing the FPC's weed treatment program.
With no nuisance weeds detected, and adequate levels of Sonar remaining to do in any sprouts that might have escaped notice, Bellaud concluded that there is no need for a further dose of the herbicide. The popular swimming hole has been treated twice this summer - initially on June 5, with a "booster treatment" on June 29.
"Dug Pond" Inspection Finds No Fanwort - But There's Some in the Channel
August, 2006
Technicians from Aquatic Control Technology took a slow tour of "Dug Pond" on August 2, looking for fanwort. Peering through the crystal-clear water, they found none of the pesky weed in the 3.9-acre basin. Earlier treatments with Sonar have apparently eliminated that and a second non-native invader, Brazilian elodea.The technicians took a water sample, which will be sent to the lab to determine the concentration of Sonar remaining in the basin, which was last treated on June 29. Biologists at ACT will then decide whether the town-owned swimming hole requires a final booster shot of the herbicide.
But so far the results could hardly be better. The technicians reported excellent water clarity to the basin's full depth of 12.5 feet. From the shore, fish darting through the water could be seen as clearly as trout in a mountain stream.
The technicians also took a quick pass through the main Pond, where they reported finding fanwort in the channel and at the mouth of the Mill Reservoir. That is not such good news. The Corporation will seek more details from ACT, and discuss how to deal with the return of the weed.
"Dug Pond" Gets 2d Sonar Treatment
June, 2006
"Dug Pond" received a second dose of Sonar herbicide on June 29. Technicians from Aquatic Control Technology launched a small motorboat into the 3.9-acre Town-owned swimming hole at the end of Glenwood Road, taking about an hour to spray the basin.The treatment came late in the afternoon, and although the two-man team arrived just after a heavy downpour had drenched the area, neighborhood kids were already back in the water. The kids had to cut short their fun, as the basin was closed to boating, fishing and swimming for the rest of the day.
The basin received it first treatment of the slow-acting weed-killer on June 5. Both fanwort and Brazilian elodea - the invasive
aliens targeted by Corporation's weed-abatement program - are showing signs of ill-health. But Sonar, which has a short half-life, must be kept at concentration of between 10 and 20 parts per billion throughout a treatment period of 60 to 90 days in order to eradicate the weeds. That means applying "booster" doses once or twice during the Summer.
Brazilian elodea taken from "Dug Pond" on June 29 showing signs that Sonar is killing the nuisance weed. Healthy plants are bright green, with no pink or white. ACT senior biologist Marc Bellaud, who headed the treatment team, said he would return in about three weeks to assess progress. He said that if the fanwort and Brazilian elodea continue to succumb, a second booster treatment may be unnecessary.
Water from the treated basin should not be used to irrigate plants until September 6, since treated pond water could have the same lethal effect if sprayed on tender land plants.
"Weed Watchers" Train for Guard Duty
June, 2006
"We call this the 'Green Book'," said Michelle Robinson, passing out copies of a colorful pamphlet picturing on its cover a dense green mat of lily pads with a pair of cheerful yellow flowers. "It's a lot easier to remember than the full name."That would be A Guide to Selected Invasive Non-native Aquatic Species in Massachusetts, and Robinson - an expert on the subject employed by the Department of Conservation and Recreation's Lakes and Pond Program - had come to Andover to train volunteers from the Foster's Pond community on how to identify them.
Nine area residents spent two hours in the cafeteria of South School, gently spreading the leaves of two dozen dripping
specimens, holding them up to the light to look for leaf arrangements, serrations, and bladders, as Robinson guided them through the terminology and techniques of plant identification.
Michelle Robinson (standing) gives pointers to Foster's Pond residents Kenny Tamarkin and Dick Tyler. The idea of the State "Weed Watchers" program - and the reason the Foster's Pond Corporation organized the June 19 training session - is that residents who are frequently out on a pond can be the first line of defense if they recognize a new invasive species or the re-emergence of a pest that's been around for awhile. But they need to know what to look for.
The "Green Book" is like an aquatic version of the FBI's 10-most-wanted list. After giving her students plenty of time to practice identification techniques on a range of native and non-native plants - including specimens one participant had plucked from Foster's Pond earlier in the day - Robinson rounded up examples of some of the worst offenders for what amounted to a watery "perp walk" of villainous weeds.
(L. to r.) Becci Backman, Amy Janovsky, and Lydia Cardin learn identification techniques from Michelle Robinson. There was good news and bad news in the display. The good news: Sprigs of fanwort from "Dug Pond," were already showing signs of chlorosis,
the bleaching effect caused by the Sonar herbicide with which the basin was treated just two weeks earlier. And more good news: The specimens of variable milfoil and Eurasian milfoil had come from another pond. Neither of these dreaded aliens has been found in Foster's Pond.
Fanwort taken from Dug Pond June 19, showing signs of chlorosis. On untreated plants, those white tips would be bright green. But there was some bad news, as well. One of the samples taken from Foster's Pond turned out to be curly-leaved pondweed (Potamogeton crispus), a species that had escaped detection in surveys conducted in August 2004 and September 2005.
Bad news: Curly-leaved pondweed was found in Foster's Pond on June 19.The reason no curly-leaved pondweed showed up on the biologist's rake in the earlier surveys is that both were done in late summer, and this type of pondweed has a unique growing pattern. The plant grows early and quickly, dropping seeds by late spring or early summer, then dying back by July. The seeds sprout in the fall, with the small plants emerging in September, wintering over when ice forms, then putting on a growth spurt when the water warms. Sonar kills curly-leaved pondweed, but last year's treatment obviously did not result in complete eradication.
"Dug Pond" Receives Treatment for Nuisance Weeds
June, 2006
"Dug Pond" got a dose of the Foster's Pond Corporation weed program, as technicians sprayed the Town-owned swimming hole with a slow-acting herbicide on June 5.After months of hearings, planning, and fundraising, the treatment process caused barely a ripple in the 3.9-acre basin at the end of Glenwood Road.
Biologist Keith Gazaille rowed an 8' aluminum boat across the glassy waters of the basin, as his youthful assistant
Steve Metzger aimed the nozzle of a power sprayer which sent a wispy arc of the diluted solution 30' off the stern. They crisscrossed the small, tree-ringed cove for about an hour.
Technicians spray a dilute solution of Sonar into Dug Pond Gazaille and Metzger are employed by Aquatic Control Technology, the lake management company hired by the FPC to implement a nuisance weed control program in Foster's Pond. The Dug Pond treatment used the same herbicide - Sonar, the trade name for fluridone - that last year was applied in the main pond to combat fanwort. Dug Pond, which is separated from the main pond by a narrow berm, was not treated last year, but later inspection found both fanwort and another nonnative invasive weed, Brazilian elodea, growing in the smaller basin, and Sonar is effective against both.
Indeed, Sonar is the only proven antidote to fanwort that environmental authorities allow in Massachusetts. It kills submerged aquatic plants by blocking their formation of carotene, which protects the plants' chlorophyll from degrading in sunlight. As the chlorophyll bleaches out, the plant dies - usually over a period of 30 to 90 days. The bleaching process is known as chlorosis.
Sonar is effective at a very low concentration - 10 to 20 parts per billion. At that level, it is allowed in public drinking water reservoirs. That was the concentration Gazaille was aiming for, and the dose sprayed into Dug Pond was calibrated on the basis of depth soundings, from which the basin's volume was calculated.
Prior to beginning the treatment, Gazaille and Metzger posted orange notices closing the basin to swimming, boating and fishing for the rest of the day. Water from the basin should not be used for irrigation for the next 90 days.
Sonar has a short half-life, breaking down quickly in sunlight. Gazaille will return to Dug Pond in a week or ten days to take water samples, which will be tested to determine the Sonar concentration remaining in the basin. As the concentration declines to 10 ppb, the basin will receive a booster treatment. One or two such boosters are likely to be needed during the 90-day treatment period.
"Dug Pond" Treatment Scheduled for June 5
May, 2006
Treatment of weeds in "Dug Pond" has been scheduled for June 5. The 3.9-acre basin will be closed for swimming, boating and fishing for the day, but will re-open June 6.Technicians from Aquatic Control Technology, the lake management company hired by the Foster's Pond Corporation to combat nuisance weeds in Foster's Pond, will launch a 12-foot motorboat into Dug Pond on Monday morning, using a combination of pelletized and liquid Sonar to kill nonnative weeds in the popular swimming hole.
The pellets will be scattered across the basin using a blower, while the liquid will be sprayed on the surface. Sonar
(the brand name for fluridone) kills submerged aquatic plants by blocking their formation of carotene, which protects the plants' chlorophyll from degrading in sunlight. As the chlorophyll bleaches out, the plant is unable to produce carbohydrates, and it dies - usually over a period of 30 to 90 days. Biologists regard the slow rate of die-off as a benefit of fluridone, minimizing the risk that decaying plants will deplete oxygen in the water.
June 2005: Fanwort fades after 1st Sonar treatment in main pond
A key to the success of a Sonar treatment is keeping the proper concentration in the water over an extended period. The target concentration is between 10 and 20 parts per billion - a level sufficient to kill the target plant species but regarded by State and Federal regulators as safe even for public drinking water supplies.
Sonar has a short half-life, degrading in sunlight. So samples will be taken from Dug Pond every couple of weeks to see if "booster treatments" are needed to maintain a concentration that will kill the weeds. One or two "booster" treatments are anticipated. Heavy rains could also affect the need for "boosters" - especially if the water level in "Dug Pond" rises high enough for water (and some Sonar) to spill out into the main pond. As of May 29, water in "Dug Pond" was lapping at the top of the narrow berm which separates the small Town-owned basin from the main pond, but there was no perceptible flow.
June 19 "Weed Watchers" Class Is Almost Full
May, 2006
Become a "Weed Watcher"! It's one way you can help protect Foster's Pond from prematurely succumbing to a resurgence of fanwort - or any other nonnative nuisance weed seeking to take up residence here.The Corporation is sponsoring a free class for volunteers on June 19 from 7 - 9 p.m. To sign up, and get the location, e-mail info@fosterspond.com. But don't wait too long! The training is limited to 15 participants, and the class is filling fast.
The class will be conducted by staff from the Massachusetts Department of Conservation's Lakes & Ponds Program, which encourages local pond associations to train members in weed identification and conduct regular monitoring. If small infestations are detected in time, there are low-cost, environmentally friendly eradication techniques that can reduce the need to resort to expensive herbicide treatments.
So sign up - and bring in your own sample of any weed you've found in the Pond! For a more detailed description of the State's Weed Watchers Program, visit the DCR web site.
FPC Signs Contract for "Dug Pond" Weed Treatment
May, 2006
The contract has been inked; the permits are all in place; and the weeds have started to grow. Now it's up to the biologists to set the date for applying Sonar, the slow-acting herbicide which will kill nonnative aquatic nuisances just beginning to emerge from the sediments of "Dug Pond."Two biologists from Aquatic Control Technology, the lake management company which treated Foster's Pond last year and will apply the same chemical to near-by "Dug Pond", inspected the 3.9-acre basin on May 12. They reported finding that both target species - fanwort and Brazilian elodea - are actively growing but are "very small."
The first treatment has not yet been scheduled but will likely take place later this month or in early June. May's torrential rains and flood conditions are not helpful, as the key to a successful Sonar treatment is to keep a steady concentration over a period of at least 60 days - not easy to do if Mother Nature is diluting the mix.
"Dug Pond" is owned by the Town of Andover. The Foster's Pond Corporation has raised the $5,750 it will take to treat the popular swimming hole, which is separated from the rest of Foster's Pond by a narrow berm and flows into the larger water body. FPC President Steve Cotton signed the treatment contract with Aquatic Control Technology May 16.
Fund Drive Tops Goal; Look Out, Weeds!
May, 2006
With donations from area residents totaling more than $7,000, the Foster's Pond Corporation has made the formal decision to undertake the treatment of "Dug Pond" with Sonar this summer.The FPC Board of Directors voted unanimously May 7 to contract with Aquatic Control Technology (ACT) to apply the herbicide to the 3.9-acre basin on Glenwood Road. Last year, ACT - the Corporation's long-time lake management
consultant - found infestations of two invasive weeds, fanwort and Brazilian elodea, in the popular swimming hole, which is separated from the rest of Foster's Pond by a narrow berm. The cost of the treatment will be $5,750.
The first step in the process will be a visit from ACT's senior biologist, who will determine the best time to apply the slow-acting herbicide. To be effective, Sonar must be infused in the water just as the target weeds begin their summer growth, usually in early to mid-June. The FPC's treatment plan was approved by the Andover Conservation Commission in February.
When the initial treatment date is established, abutters will be notified. The basin will be posted on the day of the treatment
with warnings against swimming, fishing or boating on that day. Because Sonar has a short half-life - it degrades in sunlight - one or two booster applications are likely to be needed, and the basin will be posted again for each new treatment. Water in the basin should not be used for irrigation throughout the treatment period, since it will have the same lethal effect if sprayed on land that it has on submerged aquatic plants. Sonar is applied to a pond through underwater hoses, leaving emergent wetlands vegetation and land plants unaffected.
"Dug Pond" Fund Drive at 60% of Goal
April, 2006
The Foster's Pond Corporation drive to raise funds for treating invasive weeds in the Glenwood Road basin topped 60% of the target as of April 18.
The project will cost $5,750. Contributions - most of them from residents living near the 3.9-acre Town-owned swimming hole - now total $3,500.
To make a tax-deductible contribution, visit our donation page.
FPC Kicks Off Fund Drive for "Dug Pond" Treatment
March, 2006
The Foster's Pond Corporation has appealed to area residents for money to fund treating the Glenwood Road basin with Sonar this Spring.
The fund drive targets Andover residents in the immediate vicinity of the popular swimming hole, which is locally known as "Dug Pond."
The former gravel pit, now a shallow 3.9-acre basin at the end of Glenwood Road, is infested with fanwort, a non-native invasive weed that plagued Foster's Pond for years until theCorporation undertook a successful herbicide treatment in 2005. Dug Pond, separated from Foster's Pond by a narrow berm, empties into its much larger neighbor, carrying seeds and weed fragments that are likely to reestablish fanwort in the 120-acre main water body.
Glenwood Road basin (or "Dug Pond"), showing areas infested with fanwort
In a letter mailed to residents in the Glenwood Road/Morningside Drive area, FPC President Steve Cotton asked for contributions "to save this wonderful resource in your backyard."
The treatment plan, which has been authorized by the Andover Conservation Commission, will cost $5,750.
The treatment consists of injecting a diluted herbicide through weighted hoses just below the water surface. The herbicide - fluridone, sold under the brand name Sonar - prevents green plants from producing yellow pigments which protect chlorophyll in the plants from breaking down under sunlight. Without the yellow pigments, the plants slowly bleach out and die, a process known as chlorosis. Sonar is the least toxic herbicide approved in Massachusetts for use against aquatic weeds, and the only one effective against fanwort. ( To read a technical review of fluridone, contained in the State's encyclopedic Generic Environmental Impact Report on aquatic plant management, click here.)
Under the treatment program approved by the Conservation Commission,Sonar concentrations in the treated basin would be maintained at between ten and 20 parts per billion - a level which State and Federal regulators allow in reservoirs used for public drinking water. That level is maintained for 60 to 90 days, allowing the fanwort to absorb the chemical and gradually die off. The slow die-off is regarded as a virtue of the Sonar treatment,
August 2004: Fanwort in the main pond
reducing the likelihood that the weed kill will lower oxygen levels in the water.
June 2005: Fanwort shows signs of chlorosis after 1st Sonar treatment in main pond
Temporary water use restrictions endorsed by the Andover Board of Health for the Foster's Pond weed control program prohibit swimming, boating or fishing in the treated water body on the day Sonar is injected. Because the chemical has a short half-life, breaking down in sunlight, one or two "booster" applications may needed in the course of a 60-day period. (Two booster treatments were applied to Foster's Pond in 2005.) Throughout the treatment period, water from the treated basin should not be used for irrigation, since the treated water will have the same effect on lawns as it has on the fanwort.
Sonar is not a permanent solution to the fanwort problem. Treatments typically hold for two or three years, though they may endure for longer periods. But there is no alternative. Leaving fanwort untreated - as was the case in Foster's Pond itself for decades - can lead to a pond-clogging explosion of growth that chokes out other plants, overtakes natural habitats, and precludes fishing, swimming, or boating. There are no biological controls, such as the weevil that eats Eurasian watermilfoil. And while some states permit the use of grass carp to control aquatic weeds, Massachusetts flatly prohibits their use - noting that they can grow into four-foot long, 100-pound behemoths, spread disease, decimate native flora and fauna, and increase algae. In its most comprehensive environmental review, the State's Department of Environmental Protection has termed the use of herbicides to control fanwort "a necessity until some other more long-term control, such as plant-eating insects, can be established."
The fund-raising drive has a deadline imposed by nature. Sonar is only effective against fanwort if applied when the weed is just starting to grow - usually, late May or early June. The first Sonar treatment in last year's successful program was on June 6. There's about a month of pretreatment paperwork required, so the money must be in hand by mid-April for the project to proceed this year.
Download a contribution form.
Conservation Commission OKs Plan to Treat Glenwood Basin
February, 2006
The Andover Conservation Commission has unanimously approved the Foster's Pond Corporation plan to treat the Glenwood Road basin with Sonar this spring.
The February 21 vote sets the stage for the FPC to begin raising the $5,750 cost of the herbicide treatment of the 3.9-acre swimming hole, which is separated by a narrow berm from the rest of Foster's Pond. If the funds are raised, the treatment will begin in late May or early June.
Details of the 2006 treatment plan are contained in a two-page letter to FPC president Steve Cotton from the Corporation's consultant, Aquatic Control Technology. It was this plan that the Commission voted to approve. The treatment of the Glenwood Road basin will be subject to the same Order of Conditions approved by the Commission last year - and upheld by the State's Department of Environmental Protection - to govern weed treatments in Foster's Pond and the adjacent basin.
Last year,the Corporation undertook a $42,500 treatment of the main pond to combat fanwort, a non-native invasive weed that had taken over most of the pond's 120 acres. By mid-summer, the weed - which in previous years was so thick it could be raked in large clumps from the surface - had all but vanished.
August 2004: Fanwort in the main pond
But the same careful survey which found fanwort virtually eradicated from the main pondturned up an alarming infestation in the Glenwood Road basin, more familiarly known as the "dug pond." A second non-native invader, Brazilian elodea, was also detected.
Glenwood Road basin (or "dug pond"), showing areas infested with fanwort
And that could spell trouble not only for the smaller water body - where swimmers complained of being caught up in the weeds - but for the newly cleared main pond. Through much of year, water flows from the Glenwood Road basin into the main pond, and since fanwort spreads both by seeds and fragmentation, that flow is likely to carry the fast-growing weed back into Foster's Pond, where it will quickly re-establish itself.
The Corporation voted in January to tackle the weed problem in the Glenwood Road basin - if contributors come through with the $5,750 cost. The money must be raised quickly, because Sonar - to be effective - must be applied early in the growing season. That usually means sometime between mid-May and early June.
To contribute to this effort, download a contribution form. Your contribution is tax-deductible.
Conservation Commission to Vote February 21 on Glenwood Basin Weeds
February, 2006
The Andover Conservation Commission, after a brief discussion of the Foster's Pond Corporation plan to treat weeds in the Glenwood Road basin, took no action February 7, postponing a vote until the Commission's next meeting.
That meeting is scheduled for February 21.
The FPC proposal was Item #26 on the Commission's February 7 agenda, and - following a two-hour discussion of changes to the Andover wetlands regulations - a weary commission called on FPC President Steve Cotton to address the weed proposal at 10:57 p.m. Earlier, Commission Chairman Don Cooper had said that he would impose an 11:00 p.m. "curfew" on the meeting, which had been scheduled to end at ten. Cooper also announced that with so little time available, he would not put the weed matter to a vote.
Cotton asked the Commission to act at its next meeting, pointing out that Sonar - the only herbicide that works on the nuisance weeds in the basin - must be applied during a narrow window from mid-May to early June in order to be effective. He said the FPC would need time to raise the $5,500 to $6,000 cost of the project and sign a contract with the applicator - who, in turn, will need approximately a month to secure the State permit required for each use of an aquatic herbicide.
The formal issue to be decided by the Commission is whether the treatment of the 3.9-acre basin - which neighbors call the "dug pond" - represents a "significant" change to the treatment plan for Foster's Pond authorized by the Commission last year, and that new conditions are needed to govern treatment of the former gravel pit. If so, a lengthy hearing process will be required, starting with formal notices to abutters and advertising in local papers; if not, a simple majority vote will greenlight the project.
The FPC position is that a 2006 follow-up treatment is not a "significant" change in the plan - and was indeed authorized by the Commission's 2005 approval of herbicidal treatment of nuisance vegetation in the Pond. That approval, which included an Order of Conditions which was subsequently upheld by the State's Department of Environmental Protection, encompassed the Glenwood Road basin, specifically listing the book and page number at the Registry of Deeds where the Town recorded its 1990 Order of Taking of the popular swimming hole. It also allows Sonar treatments, as needed through 2009, subject to advance approval by a majority vote of the Commission.
The 2005 treatment program approved by the Commission targeted the 120 acres of the main pond - but left out the much smaller Glenwood Road basin. Now that fanwort - and Brazilian elodea, another invasive nuisance - have been found in the "dug pond," the Corporation's weed consultant has recommended treatment. The Glenwood Road basin empties into the main pond in high water conditions, and seeds or fragments of the nuisance weeds carried into the larger water body can root and spread.
Conservation Commission to Consider Glenwood Basin Weeds
February, 2006
The Andover Conservation Commission is scheduled to take up a recommendation by the Foster's Pond Corporation to allow Sonar treatment of the Glenwood Road basin. The matter will come before the Commission at its February 7 meeting.
The 3.9-acre former gravel pit off Glenwood Road is owned by the Town. It is separated from the rest of Foster's Pond by a narrow berm, but in high water conditions, the spring-fed basin flows into the main pond. The basin was found last year by the Corporation's weed consultant to be infested with fanwort - the invasive nuisance that was virtually eliminated from the main pond by a $42,500 treatment program. The consultant warned that fanwort - as well as a second invasive plant, Brazilian elodea, which had not been found in the main pond - could spread if not treated in 2006.
FPC President Steve Cotton will present the consultant's findings and urge the Commission to authorize treating the basin with Sonar, the herbicide used in the 2005 to get rid of the nuisance weeds in the main pond. An affirmative vote on Tuesday would allow the Corporation to initiate efforts to raise the $5500 to $6000 cost of the treatment.
Corporation Endorses Treatment of Glenwood Road Basin
January, 2006
Corporation members voted unanimously January 17 to seek Sonar treatment of the Town-owned Glenwood Road basin. The former gravel pit, separated in all but the highest water conditions from the rest of Foster's Pond by a narrow berm, was not treated in 2005.
But the Corporation's weed consultant found fanwort in the 3.9-acre basin last fall,and recommended treatment to forestall reinfestation of the remainder of the Pond. The consultant, in a year-end report to the Corporation, estimated the cost at $5500 to $6000. The consultant also found a second invasive weed in the basin -Brazilian elodea - that had not been found elsewhere in Foster's Pond.
Glenwood Road basin, showing areas infested with fanwort
At the Corporation's annual meeting January 17, members strongly supported treatment of the Glenwood Road basin, a favorite swimming spot for residents of Glenwood and Snowberry Roads. The basin is ringed by Town conservation land. The Town acquired the area in 1990.
FPC President Steve Cotton is scheduled to discuss the matter with the Andover Conservation Commission on January 24. He will recommend that the Commission vote to approve treatment of the basin under the provisions of the same Order of Conditions which authorized the Corporation's 2005 weed program. That Order of Conditions is in force until 2010.
The next step after that: finding the money to undertake the project.
Final Report: Sonar Worked, But Keep an Eye Out for Weeds
January, 2006
At year's end, the Corporation's weed consultant issued its final report on the 2005 treatment of Foster's Pond with Sonar.
The conclusion: "The Sonar treatment completely controlled fanwort growth at Foster's Pond, providing greater than 99% control of the nuisance weed." In August, 2004, the non-native invader had been the dominant plant in the Pond, covering an estimated 50% of its 120 acres, the most prevalent species in 34 of 39 data point locations surveyed by senior biologist Marc Bellaud of Aquatic Control Technology. After treatment of the Pond in 2005, wrote Bellaud in his report, his survey of the same data points found that fanwort had been "nearly eliminated." He described encountering one small patch that was "highly chlorotic and unhealthy" as a result of the herbicide.
The ACT report also documents the survival of nine submerged plant species and eight floating leaf or emergent species that were nottargeted. Noting that the native submerged plants and floating-leafed water lilies had been thinned out, the report indicates that these species "typically rebound the year after treatment." The emergent species (those growing above the water line, such as cattail) were unaffected by the treatment, according to the report. The report also found no adverse effect on fish or other wildlife.
Airboat treatment path, 6/6/05; untreated Glenwood Rd. basin is dark area at top
The report, which was submitted to the Foster's Pond Corporation on December 28, makes five recommendations:
To download the full report, click here.
- Train volunteers on how to identify fanwort and pull it out by hand. Fanwort is easily confused with native look-alikes which are not troublesome. And it must be pulled out carefully by the roots, as floating fragments can develop roots, sink to the bottom, and regenerate. The State runs a "weed-watchers program" which sends experts out to train local groups; State personnel have offered to come to Andover to run a training session for the FPC.
- Conduct a follow-up plant survey in 2006. Under this recommendation, ACT would return to take samples at each of the 39 data points surveyed in the prior studies, documenting conditions and keeping track of weed growth and the appearance of fanwort or any other nuisance plant. The cost: $1,750.
- Treat the dredged basis off Glenwood Road. This 3.9-acre pool is a former gravel pit that, at low water, is separated from the rest of the Pond by a narrow berm. At high water, it merges with the rest of the Pond. Almost all of the land around it is owned by the Town, and it provides public access (albeit, with no parking) for swimming. It was not treated in 2005. But Bellaud discovered that it does contain patches of fanwort, as well as another non-native pest, Brazilian elodea. The recommendation: spot-treatment with Sonar at a cost of $5,500 to $6,000.
- Two further recommendations, if and when conditions warrant, are for using bottom weed barriers on small, dense beds of fanwort or, if larger areas appear, spot-treating them with Sonar.
Biologist Returns for Post-Treatment Assessment
September, 2005
The rake told the story. Again and again, Marc Bellaud tossed it overboard, dragging it a few feet across the bottom of Foster's Pond. And again and again, itcame up with a few leaves, or a handful of filamentous algae. What it didn't come up with was a huge clump of the fanwort that last year - and for many previous years - choked all but the deepest parts of the Pond.
ACT Biologist Marc Bellaud
"I'm not seeing any," said Bellaud, who is senior biologist at Aquatic Control Technology, the contractor employed by the Foster's Pond Corporation to consult on weeds and apply Sonar to the Pond earlier in the summer. "Not even remnants."
Later in the sampling process, he dredged up sickly strands of fanwort in two spots. The larger patch was an outcropping about a foot in diameter in two feet of water in the northerly cove between Azalea Drive and Snowberry Road.
August 2004: This year, the rake was empty
"This is in pretty rough shape," he said as he examined a decaying stem. "I don't think it's going to make it."
Bellaud, accompanied by FPC President Steve Cotton, criss-crossed the Pond in an 8-foot flat-bottomed boat on September 14, using a GPS locator to find each of the 39 points from which he had taken samples in August, 2004. That's when ACT undertook the plant survey that led to the use of Sonar herbicide to control fanwort. The 2004 survey found fanwort to be "the most prevalent [plant] species" in 34 of the locations.
Bellaud stopped at the same spots and tossed the rake in. He came up with a number of native species, including coontail, but the fanwort had all but vanished. (For some before-and-after pictures of the Pond, taken in August 2004 and August 2005, see Weeds Wilt, below.)
Bellaud raked the bottom, peered into an underwater TV camera, tested for oxygen levels, and assessed water clarity. The data will go into a written report that ACT will submit to the Corporation later this year. As he worked, he also answered a series of questions that residents had e-mailed to Cotton.
[Note: Some of the questions have been slightly paraphrased. The answers are based on notes, not an electronic recording.]
Q: Will hydro-raking spread the cabomba (fanwort)?
A: Not now. I doubt very much there are any viable roots which are hardy enough that the hydro-rake uncovering them will stimulate new growth.
Q: What are those huge floating things that look like pineapples? Should we try to get them out of the water? What will happen to them if we do nothing?
A: Those are lily roots. When they float, they're pretty severely beat up, andthey're dying. The decay produces gasses, and that's what causes them to float. Eventually, they'll sink to the bottom, decompose, and turn into muck. That will happen when we get colder temperatures. Frost will stop the decomposition and the build-up of gasses. A small percentage may hang on and re-root. You can see some small sprouts in some of them. Certainly, getting the floating roots out of the water is not a bad thing to do. But they can smell pretty horrible when they break down on dry land. They can give off an ammonia smell.
Q: What can we do to treat the water lilies that come back?
A: I'm surprised we saw so much impact on the lilies. Often, we don't see as much of an effect, particularly along the shorelines. We can expect them to come back, but in fairly reduced densities next year. You can still see a lot of lilies growing. Where you see the sickly leaves at the surface, you can expect to see them back. In places where we see the lilies with more green to them [for example, the channel and Mill Reservoir], they will certainly be back next year.
For individual homeowners, hydro-raking gets out the lilies and the muck. Purely from a cost standpoint, for control of the weeds, glyphosate is cheaper and probably more long-lasting. It's a topical treatment on the pads themselves. Typically, it's applied mid to late summer. The active ingredient is what's in Round-Up. Rodeo is the product that's approved for use in the water. Of course, individuals can't use it. It has to be applied by a licensed applicator.
Q: What's the effect of the dead fanwort on the oxygen and pH levels in the Pond? Has additional biomass started to decay, hastening eutrophication?
A: The effect on oxygen has been fairly low, because the plants die so slowly. There isn't a great surge of plants dying all at once, which would have greater effect. The pH is not affected. [Note: In the absence of Sonar, the fanwort would have grown more robustly, and then, at the end of the season, died, fallen back in the water column, and decayed.]
Q: Why has the Pond become a Gatorade color over the past week? When can we expect that condition to pass?
A: The color you're seeing may be a reflection off the Pond bottom, based on the low water level and the absence of fanwort you've seen in the past. You're also seeing the effects of microscopic algae in the water. Because of the low water level, no water is flowing over the dam, so there's a lack of flushing. That affects water clarity, too. Cooler temperatures will make a difference. And next year, you'll see less algae and greater water clarity.
Q: What has the effect been on native plants? Will they rebound?
A: Native plants have taken a hit, too, but they'll come back. You'll see recolonization of the bladderwort. The coontail will come back. We also saw stonewart - that's a type of algae [near the Goldsmith shoreline]. That's good to see. It's a kind of aquatic mulch, and it provides good habitat. That may have a chance to spread.
Q: What is your estimate of what the Pond will look like over the next few years?
A: Next year it's going to look great. There will be very little fanwort. The lilies will start to come back. I expect less algae, better water clarity. Usually, we see two to three years of very good control [of fanwort]. After four to five years, people begin to ask for retreatment. But predictions beyond the second year start to get a little dicey.
Q: Could we have gotten these results with a big drawdown and hand-pulling?
A: No way. You couldn't draw this pond down enough. You'd have to re-engineer your dam, and I don't think you could get State approval to draw the Pond down far enough even then. If you have low enough density, in a small area, hand-pulling would be a good option to keep the fanwort at bay. In anything 4 feet deep or greater, hand-pulling means diving. It's very slow work. You need to take the time to get out the roots. If you break it off, you'll spread it. Having acres and acres of high-density fanwort - like what you had here - makes hand-pulling impractical.
Q: Would it make sense for us to train some volunteers under the State's "weed-watchers" program to look for fanwort outbreaks?
A: Yes. If you see any next year, it will be late in the season. If you see it when it's low enough density, you can consider hand-pulling. That would be a good option to keep it at bay. In '07, you may need to consider spot treatment if you find an isolated patch in a protected cove. But spot treatment is going to be very hard if you find it in the main Pond, because the Sonar won't stay in one place.
Q: Why is there increased pondweed in Frye's Brook? Is it related to Sonar?
A: The ribbon-leaf pondweed in Frye's Brook is a good plant. It's native, and it's slow-growing. It propagates by seeding itself. I don't know why you're seeing more of it this year, but Sonar would not have anything to do with the increase. It may have something to do with siltation from the sewer project upstream; maybe some seeds washed downstream. We've seen some ribbon-leaf pondweed in the Pond, but it's not something to worry about.
As Fanwort Fades, No More Treatments On Tap
August 2005
With the Pond's fanwort invasion in full retreat, Aquatic Control Technology has concluded that the nuisance weed will continue to die without another round of herbicide treatment.
ACT was responding to laboratory analysis of water samples taken August 11, when the company's senior biologist, Marc Bellaud, toured the Pond to observe the progress of the Corporation's weed control efforts. What little fanwort he could find - even in coves that had been clogged with the stuff this time last year - was stunted and decayed, exhibiting no bright-green tips of viable growth.
He said then that even very low levels of Sonar - the herbicide which has broken fanwort's chokehold - would be adequate to finish the job of killing the non-native species which had become the dominant plant in most of the Pond.
Throughout the treatment regimen, which began June 6, the aim had been to keep the Sonar concentrations at 10 to 20 parts per billion - with 10 ppb adequate to kill healthy fanwort, and 20 ppb considered by State and Federal regulators to be safe even in public drinking water.
The newest test results show that Sonar concentrations in the main Pond - last treated on July 14 - had fallen to 11.9 ppb and 9.6 ppb at the two locations which were sampled. In the Mill Reservoir (the excavated cove near Azalea Drive, where Frye's Brook empties into the Pond, diluting the water), the concentration was 6.6 ppb. In the channel, the Sonar level stood at 13.2 ppb.
These concentrations were considerably lower than they had been in samples tested in late July, reflecting Sonar's short half-life as it deteriorates in sunlight. But in ACT's view, the levels are adequate to do in the already-weakened fanwort.
In an e-mail to FPC President Steve Cotton on August 16, Bellaud stated:
The lakewide average is still over 10 ppb. Mill Reservoir continues to be lower (6.6 ppb), but we didn't find any viable fanwort in there. Considering the condition of the remaining fanwort plants and the higher than expected Sonar concentrations, we are comfortable saying that another booster treatment is not needed. The plants should be completely controlled within the next couple of weeks.
Experts from ACT will return to the Pond in mid-September for another inspection.
Biologist Finds Fanwort Die-Off Throughout Pond
August 2005
Aquatic Control Technology's senior biologist, Marc Bellaud, inspected the Pond August 11, looking for signs that any fanwort might have survived the herbicide treatment aimed at destroying the nuisance weed. But as an assistant dropped a rake, time and again, over the side of ACT's aluminum motorboat, dragging the bottom for weeds, what came up was some algae, a few strands of native coontail, and - occasionally - some stunted and decaying fanwort stems.
Bellaud's conclusion: the Pond will probably not need further treatment this summer as the fanwort die-off progresses. He took water samples, which will be sent to a lab, to determine Sonar concentrations, but said that fanwort in the Pond now appears so weakened that whatever Sonar remains in the Pond will likely be enough to finish the job of killing the non-native pest. Results from the lab tests will be known next week, at which time a final decision will be made about further treatment.
Bellaud noted that algae concentrations in the Pond may have increased somewhat as a result of the Sonar treatment, due to added nutrients from decaying plants killed by the herbicide. But he said that ponds throughout Massachusetts are experiencing increased algae blooms this summer as a consequence of high temperatures and sunny weather. He predicted that next year, as water lilies and other native plants rebound from this year's Sonar treatment, the algae will decline.
Weeds Wilt As Sonar Levels Hold Steady
August 2005
Fanwort in the channel, August 16, 2004
Same location, August 5, 2005
To the delight of area residents, the Sonar treatment of Foster's Pond has visibly cut the dense weed growth that last summer choked even the deepest areas. For the first time in years, previously impenetrable coves are now open to swimming, canoeing, and fishing.
Dave Brown went swimming in the channel from his Glenwood Road dock. Steve Cotton swam to the middle of the main Pond from his dock on Pomeroy Road. And Andover Street resident Jon Richards went fishing for the first time since last year. No big deal - except that all three were amazed to find that they encountered few weeds.
August 2004 (above); August 2005 (right)
As Jon wrote of his experience,
I was STUNNED to see the improvement!...[T]he results are nothing short of dramatic. There is very little sign of ANY visible fanwort in all the areas of the pond that we encountered. Last year on the eastern side of the pond, there was such a large mat of fanwort that we could not fish that area out to almost one-third of the way into the large part of the Pond. Yesterday we were able to fish within a few yards of shore. I never even caught a piece of fanwort on my fishing lures! . . . Oh, and by the way, fishing was better than ever. I caught six different species of very healthy looking specimens, and my friend caught and released a beautiful six-pound largemouth!Laboratory tests of water samples taken on July 27 showed Sonar concentrations in all parts of the Pond holding steady at just the right levels to kill fanwort, the nuisance weed that is the target of the herbicide treatment program. In the main Pond, two samples showed concentrations of 14.2 parts per billion and 13.9 ppb. A sample from the channel had a concentration of 15.2 ppb, while the Mill Reservoir - showing the dilution effect of the inflow from Frye's Brook - had a concentration of 12.6 ppb. A concentration above 10 ppb is effective against fanwort. The maximum concentration allowed under the Corporation's permit is 20 ppb - a level that regulators regard as safe even for such sensitive waters as public drinking supplies.
Based on the newest readings, weed control experts at Aquatic Control Technology determined that there was no immediate need for a third "booster treatment." They will visit the Pond in the next week or so to assess the condition of the weeds and decide whether further testing - or treatment - will be necessary.
August 2004 (left); August 2005 (above)
But for many residents, it didn't take an expert to tell them that the Sonar has made a huge - and welcome - difference.
Fundraising Goal Topped: FPC Raises $43,100
September, 2005
The contract for treating Foster's Pond with Sonar had a price tag of $42,500, and that was the goal set by the Corporation's Fundraising Committee back in April.
It took just four months to get there. As of the end of July, FPC Treasurer David Brown and Fundraising Committee Chairman Marty Rabinowitz reported contributions totaling $40, 850, with another $1,650 pledged. By September 10, contributions totaled $43,100.
The money came from 58 households in the Foster's Pond area - and one Andover contributor who lives a couple of miles away. To see a list of contributors, click here.
The Corporation will need more money to deal with expected weed re-infestations, and for maintaining the Foster's Pond Dam. Contributions are always welcome. To download a donation form, click here.
Second Booster Treatment Targets Pond July 14; Water Use Restrictions In Effect
July 2005
With its invasive fanwort in slow retreat, Foster's Pond got a second "booster" treatment of the herbicide which has begun to kill the nuisance weed.
Booster treatment #2 was applied on Thursday, July 14. One-day water use restrictions took effect Thursday, July 14 - no boating, fishing or swimming until Friday, July 15. Pond water should not be used for irrigation until September 7.
Technicians from Aquatic Control Technology launched their airboat shortly before 10 a.m., then circled the Pond, dropping off warning signs for volunteers to post. Once the signs were up, the treatment began.
The entire Pond received an infusion of Sonar, which is injected into the water through weighted hoses trailing from either side of the fast-moving craft. It took about two hours to finish the job, as the airboat - the same type of craft used to navigate swampy areas such as the Everglades - careened in and out of the Pond's lily-covered coves.
Marc Bellaud, ACT's senior biologist, was at the controls. Observing thecondition of the Pond's abundant fanwort, he said that the Sonar appears to be doing its job. He said that healthy fanwort is bright green, but he noted that fanwort in the Pond - visible a couple of feet below the water's surface, each stem looking like a test-tube brush - is a dull green or brown, with whitened tips. The sickly appearance, he said, is due to the Sonar, which causes the plant to bleach out and slowly die.
Lab results from samples taken from four locations on July 4 indicated that Sonar concentrations throughout the Pond fell, as expected, over the previous two weeks. Sonar has a short half-life, and whenever the weather turns wet, some of the chemical is washed over the dam, further lowering the concentration in the Pond.
At two locations in the main Pond, Sonar concentrations were measured at 11.6 and 11.7 parts per billion. In the channel, the reading was 11.7 parts per billion. In the Mill Reservoir (the excavated cove near Azalea Drive where Frye's Brook feeds the Pond), the concentration had fallen to 6.5 parts per billion, below the level needed to kill fanwort.
The target Sonar concentration is between 10 and 20 parts per billion - high enough to subdue the fanwort, but sufficiently low that native plant species will recover. State and Federal regulators regard 20 ppb as safe for public drinking water, and even though no one drinks directly from the Pond, the treatment plan calls for concentrations to stay within that limit.
The booster treatment will bring concentrations back up to the 20 ppb level.
Herbicide Starts Its Work: Fanwort Begins to Fade
June 2005
Three weeks after the initial Sonar treatment of Foster's Pond, the target weed began showing signs of succumbing to the slow-acting herbicide.
Fanwort, the non-native nuisance that has become the Pond's dominant plant species, is normally bright green, especially at the tips from which new growth emerges.
But those tips have faded to white, tinged with pink - the first symptoms of the herbicide's lethal effect. Sonar (the brand name for fluridone) inhibits the formation of carotene, which protects the plant's chlorophyll from degrading in sunlight. As the chlorophyll bleaches out, the plant is unable to produce carbohydrates, and it dies - usually over a period of 30 to 90 days. Biologists regard the slow rate of die-off as a benefit of fluridone, minimizing the risk that decaying plants will deplete oxygen in the water.
The Sonar is also affecting hardier plants, including native water lilies, which are fading due to the same process, known as chlorosis. The native species, however, will rebound from the low concentration of Sonar that has been applied. That concentration will not exceed 20 parts per billion, a level State and Federal regulators regard as safe enough to be allowed in public drinking water.
To be effective, the a Sonar concentration between 10 and 20 ppb must be maintained for 60 to 90 days. Since Sonar itself has a short half-life, and some is constantly being washed out of the Pond by way of the dam, periodic booster treatments are necessary.
Pond Gets Booster Treatment #1 on June 21; Water Use Restrictions in Effect
June 2005
The weed-zappers made a return visit on June 21 after getting the lab results on the initial Sonar treatment of Foster's Pond two weeks earlier.
Under sunny skies, technicians from Aquatic Control Technology whisked theirairboat from the dam through the channel, and into the Mill Reservoir, injecting a second dose of the herbicide into the weed-choked waters. No additional Sonar was applied to the main Pond.
One-day water use restrictions were put into effect Tuesday, June 21 - no boating, fishing or swimming. These uses may resume on Wednesday, June 22. Pond water should not be used for irrigation until September 7.
Water samples taken from two locations last Thursday - the Mill Reservoir near Azalea Drive and the channel, southeast of Rock Island - revealed that concentrations of the herbicide had fallen below what it takes to kill fanwort. These areas got the "booster" treatment, aimed at bringing the concentration back up to the 10 to 20 parts per billion range needed to vanquish the invasive nuisance that is choking the Pond.
Concentrations of Sonar in the main Pond were right at the target levels - 19.6 ppb at one location, and 17.2 ppb at another. But in the channel, which carries outflow towards the dam, the concentration had fallen to 8.4 ppb, just below the low end of the recommended dosage. And in the Mill Reservoir, where Frye's Brook - the Pond's main water source - flows into Foster's Pond, the concentration had fallen to an anemic 1.5 ppb.
The four water samples were taken on June 16 by Weed Committee Co-Chairman David Adilman and FPC President Steve Cotton, then sent by overnight delivery to a SePRO laboratory for analysis. SePRO is the manufacturer of Sonar. The samples were analyzed Friday, June 17, and the results provided to Aquatic Control Technology late that day. On Monday, ACT notified the FPC of the results and scheduled Tuesday's booster treatment.
The low concentrations in two areas are the result of rainy weather in the days following the June 6 treatment of the Pond. Although the FPC had attempted to draw the Pond down a full foot below the level of the dam's spillway, torrential rains prior to June 6 had left the water level even with the spillway. When the rains came after June 6, water again started spilling over the dam, and the outflow has continued. The Mill Reservoir and the channel are the areas of the Pond most directly affected by the flushing effect of these flows, and the lab results show the consequences.
The process of testing water samples from the Pond, and applying booster treatments as concentrations fall, is all part of the program. Sonar has a short half-life, and its concentration drops off no matter what the weather. In rainy weather, particularly where the outflow rises, dilution contributes to lowering the concentration. In drier conditions, when the Pond water evaporates and outflow decreases, the concentration may be maintained for a longer period. The objective of frequent testing is to keep the Sonar concentration within the target range over a period of 60 to 90 days.
The Pond will be tested again in about two weeks.
Sonar Comes in With a Roar
June 2005
The long-awaited weed treatment of Foster's Pond roared to life June 6, as technicians gunned an 18-foot airboat across the calm waters for two hours, injecting an herbicide to kill nuisance vegetation that has troubled area residents for years.
Months of planning, study, hearings, and fund-raising gave away to the spectacle
The craft is owned and operated by Aquatic Control Technology, Inc., of Sutton, Massachusetts, the contractor hired by the Foster's Pond Corporation to study the weed problem and apply the herbicide.
The airboat arrived at the Willard Circle launch site at 4:30 p.m., and was soon in the water. With ACT President Gerry Smith at the helm, and senior biologistMarc Bellaud taking readings, the boat circumnavigated the Pond to check out inflows from Frye's Brook and outflow over the dam. A week earlier, stop logs had been pulled from the dam, drawing water from the Pond. Although the plan had been to lower the Pond by one foot in preparation for the treatment, torrential rains the previous week left the water level almost exactly at the height of the dam's spillway. As the treatment began, the stop logs were replaced, reducing the outflow to practically nothing. But as the water level rises, with more rains in the forecast, Sonar will be washed out of the Pond, requiring at least one and most likely two "booster" treatments over the next two months.
The Sonar treatment lasted barely two hours, with the airboat out of the Pond by 6:45 p.m.
The Sonar was injected into the Pond through weighted hoses trailing alongside the boat. The quantity of herbicide was calculated to maintain a concentration in the Pond of 20 parts per billion - enough to kill fanwort, the non-native weed which has become the dominant plant species in much of the Pond, but so dilute that State and Federal regulators regard water with that level of Sonar as safe to drink.
Sonar acts on the weeds by retarding the production of yellow pigments whichprotect chlorophyll from breaking down under sunlight. Without the yellow pigments, the plants slowly bleach out and die. Bellaud said that residents who closely observe the fanwort - now visible in some sections of the Pond, with bright green feathery branches about a foot from the surface - may see the tips start turning white, with a pink tinge, in the next two to three weeks, the first sign that the chemical is working.
FPC volunteers will still have work to do to ensure the success of the weed program. The Fundraising Committee is continuing to contact area residents who have not yet contributed to cover the costs of the treatment. And Weed Committee members will be taking samples of Pond water, which will be tested to determine when the first "booster" treatment will be scheduled.
Sonar Contributions Top $38,500 from 50 Households
June 2005
Contributions to pay for treating the Pond with Sonar this Spring have topped 90% of the $42,500 cost of the project.
The Corporation has collected $36,275, with another $2,375 pledged, for a total of $38,650 from 50 households.
Stage Set for Sonar Treatment
June 2005
On May 31, notices went out to nearly 90 households on or near the Pond, and on June 4 orange warning signs went up on trees, mailboxes, and telephone poles near all access points. The message: Sonar is coming to Foster's Pond on June 6, and the Pond will be closed to boating, fishing and swimming for the day.
The notices and posters also advise residents not to use Pond water to irrigate plants for the next 90 days - since the treated water will have the same lethal effect on tender land plants that it is intended to have on fanwort in the Pond.
Mother Nature did not cooperate with the drawdown, however. No sooner had stop logs been removed from the dam than the skies opened up, and before the storms were over, the water level of the Pond had actually risen by about 4 inches. Indeed, so severe was the rise that, had the sluiceway not been opened, it appeared that the dam would have overtopped - a dangerous condition that is never welcome for an earthen dam. But, as the storms subsided by week's end, the Pond level started to drop, with just a trickle coming over the spillway on the Saturday leading up to the Sonar treatment. That's about 2 inches lower than when the drawdown began. With dry weather in the forecast, Dam Committee Chairman Paul Ross and Weed Committee Co-Chairman David Adilman estimated that a drop of another 2 to 3 inches might be achieved before the Sonar treatment begins.
Aquatic Control Technology, under contract with the Foster's Pond Corporation to apply Sonar to the Pond, is scheduled to perform the work Monday afternoon, June 6. ACT will launch an airboat from Willard Circle in the afternoon, then inject the herbicide into the Pond from weighted hoses. The work is expected to be finished by evening.
Drawdown Commences Under Rainy Skies
May 2005
On May 23, the Foster's Pond Corporation program to control nuisance weeds made the transition from talk to action, as Dam Committee Chairman Paul Ross removed the first "stop log" from the dam, starting the first drawdown of the Pond in more than 30 years. Paul started the drawdown at 9 a.m., under a light drizzle that continued through the day, developing into a heavier rain.
The level of the Pond will be allowed to drop by a foot in the next two weeks, in preparation for the main event - the injection of an herbicide, Sonar, to combat the fanwort invasion that is choking the Pond. That will come June 6, when the Corporation's weed abatement contractor, Aquatic Control Technology, will launch an airboat on the Pond and apply a dilute solution of the chemical through weighted hoses.
At least 90% of the targeted weed is expected to die off in the following 60 to 90 days, leaving room for native plants and clearing much of the Pond's open water of a nonnative invader regarded by State regulators (and Pond residents) as a nuisance species.
Drawdown Slated to Begin May 23 in Preparation for Sonar Treatment
May 2005
Twenty months ago, Foster's Pond area residents - meeting to revive the Foster's Pond Corporation - put weed control at the top of the organization's "To Do" list. Since then, hundreds of hours of volunteer labor have gone into studying, discussing, and devising a plan, then securing regulatory approvals and the funding to implement it. On May 23, a simple act will begin the most expansive - and expensive - weed abatement program ever attempted in this Pond: FPC Dam Committee Chairman Paul Ross will remove an 8-inch "stop log" from the dam, allowing the Pond level to start dropping gradually. In about a week, a second board will be removed, letting the Pond level fall by a total of one foot.
The aim of this drawdown - the first time the Pond level has been intentionally lowered in more than 30 years - is to retard outflow starting on June 6, when the Pond will be treated with Sonar, an herbicide that is the only effective remedy for the nuisance weed which is choking the Pond.
The drawdown, previously approved by the Andover Conservation Commission and the State's Department of Environmental Protection, received its final okay on May 18, when officials at the State's Division of Fisheries & Wildlife notified the Corporation that the drawdown could proceed. The Corporation has mailed a notice to 13 occupied Pond-area residences with shallow wells, announcing the start date and providing phone numbers to call in the unlikely event that any well loses water.
Contract Signed, Date Set for Sonar Treatment: June 6
May 2005
On May 16, the Sonar treatment plan made the turn to the home stretch. There is now a scheduled date for the initial infusion of the herbicide into the Pond: Monday, June 6.
Technicians from the FPC's licensed applicator, Aquatic Control Technology, will launch an airboat from Willard Circle, then spend the day injecting the Pond with a diluted solution so weak that State and Federal regulators say treated Pond water would be safe to drink - but strong enough that the company has guaranteed, in its contract with the FPC, that at least 90% of the biomass of the targeted fanwort will be knocked out within 60 days.
The $42,500 contract was signed May 16. Then, ACT Senior Biologist Marc Bellaud and FPC President Steve Cotton toured the Pond, with Bellaud raking the bottom at various points to determine the state of fanwort growth. New, bright green growth was just emerging from last year's plants, leading Bellaud to settle on June 6 as the right moment to zap the invasive weed with the first round of Sonar. One, and perhaps two, "booster" treatments will be applied at intervals of about 30 days.
Later the same evening, Bellaud and Cotton, joined by Weed Committee Co-Chairmen David Adilman and Mark Florio, appeared before the Andover Board of Health to finalize the temporary water use restrictions that will go into effect on the first treatment date. The Pond will be posted with bright orange signs warning against fishing, swimming and boating on June 6 - the treatment date - and further warning not to use Pond water for irrigation for the next 90 days. New signs will go up for each "booster" treatment, with the same one-day restrictions on the day the chemical is applied. The Board of Health unanimously approved these restrictions, which will also be set out in a letter to be mailed to every Pond abutter.
Corporation Board Says This is the Year: Votes to Start Sonar Treatment This Spring
May 2005
The Board of Directors of the Foster's Pond Corporation voted unanimously on May 4 to proceed with applying Sonar this Spring, while continuing to raise money to pay for the project. The vote means that the FPC's weed control program could take the plunge from printed page to treated Pond by the end of the month, as the last few pieces of the complicated regulatory picture fall into place.
The nine-member Board heard first from treasurer Dave Brown and Fundraising Committee Chairman Marty Rabinowitz, who - after tallying checks brought in by some of the Board members - reported that $29,650 had been collected so far, with another $3,700 pledged, for a total of $33,350. The cost of treating the Pond is $42,500.
Rabinowitz reported that the Fundraising Committee is confident that additional contributions will be forthcoming, and other Board members echoed this view.
The Board then took the formal action needed to move the treatment plan forward, voting to authorize President Steve Cotton to sign a contract with Aquatic Control Technology to apply the Sonar this Spring.
A biologist from Aquatic Control Technology (ACT) will look at the Pond on May 16, to check out the stage of plant growth and see what inflow and outflow conditions are like. A schedule for applying the herbicide will be determined then - with treatment likely to take place sometime between the week of May 23 and the week of June 6. There will be one and perhaps two "booster" treatments, to maintain the target concentration of 20 parts per billion, at intervals of about one month.
The Corporation has asked the State's Division of Fisheries and Wildlife (which calls itself "MassWildlife") for authorization to draw the Pond down a few inches to contain the Sonar, but treatment can proceed with or without this drawdown. In the meantime, the State's Office of Dam Safety has given a green light for the drawdown. The drawdown, earlier approved by both the Andover Conservation Commission and the State's Department of Environmental Protection, still requires an okay from MassWildlife.
Representatives of the FPC and ACT will also be meeting with the Andover Board of Health to determine whether the local Board wants to recommend any water use restrictions when Sonar is in the Pond. At the 20 ppb concentration that will be used in Foster's Pond, State and Federal regulators have set no restrictions on swimming, fishing, or drinking; the only advice on the product label is that the water not be used for irrigation for 30 days after each application, because treated water will kill the plants that are being irrigated.
If there are any water use restrictions, they will be set forth in notices the FPC will send to all Pond abutters prior to the application of Sonar. Also, warning signs will be posted at various access points to the Pond. In addition, if there is a drawdown, shallow well-owners will be notified in advance and given phone numbers to call if they lose water. Since, in past years, the Pond was drawn down much further with no water losses, no one is expected to lose water from this drawdown.
FPC Weed Program Clears Final Regulatory Hurdle: Appeal Deadline Passes, DEP Approval Becomes Final
April 2005
The Corporation's weed control program - including the use of Sonar and annual winter drawdowns - has cleared its final regulatory hurdle. The program had been approved by the Andover Conservation Commission, whose decision was affirmed by the regional office of the State's Department of Environmental Protection. The deadline for challenging the DEP action expired on April 5, with no one filing an appeal.
That means that the DEP okay is now final - or, as one DEP official put it in an e-mail to FPC President Steve Cotton, "I would say you should be set to go."
Aquatic Control Technology, the company which has advised the FPC and will apply the Sonar, must still secure a DEP license to use the herbicide in Foster's Pond, but this is a routine process which does not involve hearings and appeals. ACT will also meet with the Andover Board of Health in May to see if Town health officials want to impose stricter water use standards than those required under Federal and State regulations.
DEP Upholds Corporation Weed Program: Regional Office Turns Down Appeal By Area Resident
March 2005
The State's Department of Environmental Protection has rejected the appeal of an area resident who opposed the Corporation's plan to use a combination of Sonar and winter drawdowns to combat the spread of nuisance vegetation in Foster's Pond.
DEP's regional office approved the proposed project, affirming the Andover Conservation Commission's January 21 Order of Conditions, which had paved the way for the Corporation-backed program to go forward.
In a brief letter announcing its decision, DEP officials stated, "In the Department's opinion, the Andover Conservation Commission appropriately reviewed and conditioned the proposed project in a manner adequately protecting the interests of the [Wetlands Protection] Act." The letter was signed by Richard Tomczyk, Acting Section Chief of DEP's Wetlands and Waterways Program, and Jill Provencal, the DEP Environmental Analyst who had earlier conducted a site inspection to review the plan.
DEP issued a formal order adopting the earlier action of the Andover Conservation Commission. The DEP order is dated March 22, 2005, just one week after Ms. Provencal's site visit.
DEP Conducts Site Visit: Decision Near on Review of Conservation Commission Order
March 2005
An environmental analyst from the Regional Office of the State's Department of Environmental Protection conducted a "site inspection" on March 15, the first step in a review of the Andover Conservation Commission's approval of the Foster's Pond weed control program.
The analyst, Jill Provencal, convened the informal one-hour meeting under sunny skies. Participants stood in the driveway of 2 Foster's Pond Road, whose owners offered the venue so that attendees and their cars would be safely off the street.
DEP's review was triggered by a Pomeroy Road resident's appeal of the Conservation Commission's unanimous vote okaying the Corporations integrated management program for Foster's Pond weed control. The Commission issued three pages of "special conditions" allowing herbicide use and annual winter drawdowns.
Provencal's role at the meeting was to hear from all concerned parties. The participants included the appellant; the Town's two conservation agents, Robert Douglas and Linda Cleary; and four FPC representatives - Steve Cotton, Weed Committee Co-Chairman David Adilman (a professional hydrogeologist), Dam Committee Chairman Paul Ross, and Gerry Smith (president of Aquatic Control Technology, which produced the report on which the FPC program is based).
The appellant summarized her opposition to the Conservation Commission order, saying that herbicides "scare the hell out of me." She said that she is "totally against chemicals" for weed control, attributing the weed problem in the Pond to lawn fertilizers and faulty septic systems. She said that use of Sonar is a "Band-Aid" approach. She also opposed drawdowns, expressing concern that the proposed 18" annual drawdowns might adversely affect her artesian well. She said that her well, shown on documents filed with the Board of Health as located 500 feet from the Pond, is 345 feet deep.
Cotton gave an overview of the proposed weed control program, noting that
Cleary, speaking on behalf of the Conservation Commission, noted that Sonar has been used in a pond which is in the same watershed as the Town's drinking water supply, and has also been used in Pomp's Pond, where the Town beach is located. She said that the Conservation Commission stands by its order, which she described as tightly written with more safeguards than are usually contained in such orders.
Smith described specific projects in which the State has approved Sonar use in other ponds, noting that the plan here is completely in accordance with the State's Generic Environmental Impact Report - a comprehensive document covering all weed control techniques.
A decision by the DEP regional office - in the form of a letter sent to the parties - is expected shortly.
Weed Program Advances: Conservation Commission Issues Its Orders, 1 Resident Appeals, FPC Responds, and Fund-Raising Committee Is Launched
February 2005
The Andover Conservation Commission, after unanimously approving the Corporation's integrated management program for weed control in Foster's Pond, formally issued the final text of the rules governing the administration of the program. The three pages of "special conditions" closely follow State requirements for herbicide use and winter drawdowns. For example the Corporation's contractor (Aquatic Control Technology), will have to obtain a State permit to apply Sonar in the Pond, a routine process which will rely on extensive documentation which the Corporation has already assembled. And the Corporation will also need to secure the approval of the State's Department of Fish & Game, Division of Fisheries & Wildlife (which now calls itself "MassWildlife") before initiating any drawdown. The Corporation has previously been in touch with the responsible official at MassWildlife, and this is not likely to be a problem.
As expected, one neighborhood resident appealed the Conservation Commission's decision, requesting a review by the regional office of the Department of Environmental Protection. She expressed concern that her well would be affected by an 18-inch drawdown and by the use of Sonar in the Pond. The appeal was filed three days after the Commission's unanimous vote on January 4 in favor of the Corporation's plan - and a full two weeks before the Commission released the final text of its Amended Order of Conditions on January 21. Under State regulations, the deadline for filing an appeal from the Commission's decision was February 4. No other appeals appear to have been filed.
FPC President Steve Cotton filed a written response to the appeal on February 4, asking DEP to dismiss it. The Corporation, at its January meeting, had authorized the president to intervene in administrative proceedings to defend the Commission's order. Cotton, in a 5-page letter, argued that under State regulations the appeal should be turned down because the complaining resident - whose property is about 200 feet from the Pond, and whose well appears to be about 500 feet from the Pond, according to Town records - does not have legal "standing" to appeal. State regulations allow ten town residents to file appeals of Conservation Commission decisions, but a lone resident must show that he or she is either a direct abutter or "may suffer an injury in fact" that goes beyond something that may affect the general public.
Meanwhile, the Corporation voted at its January meeting to establish a fund-raising committee to brainstorm ways of raising the $42,000 cost of applying Sonar to Foster's Pond. The chairman of the committee, and its members, are listed above.
Conservation Commission Votes Final Approval to Corporation's Program to Control Weeds
January 2005
The Andover Conservation Commission voted unanimously on January 4 to authorize the Foster's Pond Corporation to use Sonar for the control of fanwort and to lower the level of the Pond by up to 18" each winter.
The final vote came at the end of three evening hearings on the Corporation's plan, set out in an October report commissioned by the Corporation and prepared by its weed consultant, Aquatic Control Technology, Inc.
The Commission, as part of its vote okaying an "Order of Conditions," approved a three-page set of procedures which will govern the application of Sonar and the scheduling of drawdowns. The final text will not be released until the Order is formally issued, a process which could take up to three weeks.
The Order of Conditions requires the issuance of a permit by the State Department of Environmental Protection's Division of Watershed Management prior to the use of Sonar. This permit - which is routinely issued by DEP - is obtained by the contractor which will apply the Sonar.
The contractor, under the Order of Conditions, will also meet with the Andover Board of Health prior to the initial Sonar treatment, to review the treatment schedule, application procedures and temporary water use restrictions. The FPC will be required to mail notices to abutters before Sonar is used, containing the treatment schedule and any temporary water use restrictions. (At the low concentrations of Sonar that would be used, there are no State-imposed restrictions on using well water or swimming, but the notices will likely advise residents to stay out of the water for a limited time and not use water from the Pond for irrigation for at least 30 days.)
The Order of Conditions also requires the FPC to notify the Department of Fish & Game's Division of Fisheries and Wildlife prior to any drawdown of the dam and to mail advance written notices to occupied residences which depend on shallow wells for their drinking water. Based on the Corporation's well survey (see box below), a dozen occupied homes around the Pond would be notified. Although the hydrological estimates of the Corporation's Weed Committee indicate that no one will lose water (and some shallow well users have said that they don't care, as long as it's for the good of the Pond), any drawdown will be done slowly, so that the stop logs can be restored if a problem develops.
Technically, the authorization approved by the Commission applies to the Commission itself, which undertook the burden (and expense) of being the applicant. But the Order designates the Foster's Pond Corporation to implement the "integrated management plan" for weed control. Under the plan, individual shoreline owners may continue to have hydro-raking done (following the same procedures which have been in effect, under the same permit, since 1992). The use of Sonar and annual winter drawdowns are now added to the program - along with a requirement that the FPC maintain its on-going program of educating pond abutters, other area residents, and the general public on watershed management practices to reduce the introduction of nutrients to the pond.
The Order also specifically authorizes -and indeed requires - the Corporation to maintain the dam, keeping it clear of woody brush and working with the Andover Department of Public Works to ensure that the Rattlesnake Hill Road culverts are clear of debris.
The Order approved by the Commission will expire in five years, and may be further extended.
Conservation Commission Votes Preliminary Approval of Corporation's Weed Program
December 2004
The Andover Conservation Commission gave a preliminary thumbs-up to the Corporation's multi-pronged weed control program, in two votes taken at a Commission hearing just before Christmas.
The votes followed a presentation by FPC president Steve Cotton, Weed Committee Co-Chairman Dave Adilman, and two representatives of the Corporation's weed consultant, Aquatic Control Technology, Inc. - its president, Gerry Smith, and senior biologist Marc Bellaud.
The Commission's preliminary votes - a unanimous endorsement of the FPC plan for winter drawdowns, followed by another unanimous vote to allow the use of Sonar for treatment of fanwort - set the stage for a final approval, in January, of an "Order of Conditions" detailing the procedures that will govern the weed-control efforts.
Still to come is a decision by the Corporation on whether to try to raise the estimated $40,000 cost of applying Sonar.
The Commission's preliminary votes came on the second of two evening sessions at which the FPC plan was discussed. At an introductory hearing on November 16, the FPC representatives introduced the plan, contained in a report commissioned by the Corporation in May and completed in October. The report was prepared by Aquatic Control Technology (ACT).
At the November hearing, one area resident objected to any drawdown and to the use of Sonar; two others opposed the use of Sonar. About 15 residents came to show their support for the program.
At the second session, a roomful of area residents raised their hands to show their backing for the FPC weed control program. The Commission noted that it had received one letter opposing the entire program (from the resident who had spoken at the earlier hearing); one of the other residents who had earlier opposed Sonar asked questions of the ACT representatives and indicated that she took some comfort from the efforts that would be made to minimize Sonar use and monitor the concentrations.
The FPC weed control plan, in addition to winter drawdowns and Sonar use, will continue to facilitate mechanical weed removal through hydro-raking. And the Corporation will renew its efforts to encourage the use of phosphate-free dishwashing soaps, laundry detergents, and fertilizers.
Weed Study: Drawdowns and 'Sonar' Recommended to Fight Fanwort
October 2004
Weed control experts hired by the Foster's Pond Corporation in 2004 surveyed the vegetation in the Pond and recommended an integrated program including winter drawdowns and chemical treatment to fight the fanwort - a non-native invader that has spread throughout the Pond and is now our most prevalent plant.
The report, prepared by Aquatic Control Technology, Inc., was commissioned by the Corporation in May and completed in October, with a draft submitted in time for consideration at the Corporation's September meeting. To read the entire report, click here.
The report examines all of the alternatives for managing the fanwort problem,
Herbicide use
The report notes that, because Foster's Pond owes much of its area to damming, it has "fertile bottom sediments that can support abundant aquatic plant growth." This means that our efforts to control nutrient inputs - for example, the Corporation's educational efforts to inform homeowners about using phosphorous-free detergents and organic fertilizers - are important to preserve water quality, but these efforts "will do nothing to control nuisance fanwort growth." The reason: rooted plants like fanwort draw their nutrients from bottom sediments, and even the complete shut-off of point and non-point nutrients from other sources won't suppress the spread of fanwort.
The report recommends chemical treatment as "the most effective and commonly employed means of controlling nuisance fanwort growth."
Fluridone (sold under the brand name Sonar) is the only herbicide now registered in Massachusetts for the control of fanwort. The State has approved only six active ingredients for use as aquatic herbicides, describing fluridone as "the least toxic" of those allowed in the State's lakes and ponds. This quote appears on page 4-91 of the Final Generic Environmental Impact Report (GEIR): Eutrophication and Aquatic Plant Management in Massachusetts, published in June, 2004, by the Department of Environmental Protection and Department of Conservation and Recreation. The 514-page GEIR represents the State's definitive position on the environmental effects of all management techniques. To read the entire GEIR (recommended only if you have a high-speed Internet connection or a lot of patience) click here.
How does Sonar work? It prevents green plants from producing yellow pigments which protect chlorophyll from breaking down under sunlight. Without the yellow pigments, the plants slowly bleach out and die. The process (called "chlorosis") can take upwards of 6 to 8 weeks - an advantage, since the slow dying avoids the prospect of sudden oxygen depletion (which could result in fish kills) or nutrient release (which could result in algae blooms).
Is there much experience with its use? Sonar was introduced in 1979. In 2002 (the most recent year for which data are provided in the GEIR), its use was approved for 60 water bodies in Massachusetts.
What will the effects be on shallow wells? At the concentrations that Sonar would be used in Foster's Pond for fanwort control - 20 parts per billion -Federal and State authorities allow application to potable water intakes in lakes and reservoirs. A Washington State Department of Health fact sheet (included in the Aquatic Control Technology report submitted to the Corporation) suggests: "People who wish to avoid even minimal residues can do so by filtering their drinking water with a charcoal-based filter." Shallow well-owners have a natural filter. As the same fact sheet notes, in discussing shallow wells, "Fluridone tends to bind to organic matter and should not leach into groundwater from aquatic sediments. Fluridone shows a limited ability to leach if applied to soil."
Well survey
The Weed Committee, during November and December, 2004, surveyed residents to determine the location and depth of all wells in the vicinity of the Pond. Most residents have deep wells or are supplied with Town water. In all, 15 properties are served by shallow wells; two of these are on properties unoccupied much or all of the time, and one is used only for irrigation. On average, the shallow wells are located 60' from the Pond. Even the wells closest to the Pond are - in the view of hydrogeologist David Adilman, Co-Chairman of the FPC Weed Committee - highly unlikely to be affected by a drawdown or to suck Sonar-treated water from the Pond.
Are there swimming or fishing restrictions? There are no swimming or fishing restrictions associated with use of fluridone in Massachusetts (though New York prohibits swimming for 24 hours after application). The Andover Board of Health will be given an opportunity to add restrictions on swimming or fishing , and if it does so, these will be posted before fluridone is used in the Pond. Fluridone has not been identified as a carcinogen or a mutagen. The Washington State fact sheet says, "Fluridone does not significantly bioaccumulate or biomagnify in fish." Water from the Pond should not be used for irrigation for 30 days after application (unless filtered through a charcoal filter), since it may have the same effect on the plants you're watering as on the target weeds.
Is Sonar a permanent solution? No. Sonar use is likely to provide 2 to 3 years of effective control, after which spot treatments or mechanical removal from "hot spots" might prolong control for another year or two. The cost of the initial treatment has been put at $32,250 to $42,500. In order to prolong the effectiveness of the initial treatment, the Corporation's Weed Committee will arrange for training of volunteer "weed watchers" under a program established by the State's Department of Conservation and Recreation. Our training - in which we will encourage FPC members and the general public to participate - will enable volunteers to spot re-emergence of fanwort infestations and trigger quick-reaction, low-tech (and inexpensive) responses, such as hand-pulling.
Drawdowns
The report also recommends lowering the Pond over the winter months by 12 to 18 inches. The principal reason for winter drawdowns is dam safety. At least twice in the last three years, the Foster's Pond dam has overtopped - that is, water flowing over the dam has exceeded the capacity of the concrete spillway, rushing over the earthen top of the dam on both sides of the spillway.
Overtopping is the most common cause of catastrophic failure of an earthendam, and the remedy is simple: draw down the water level of the Pond during the winter, so that there is room for the Pond to accommodate the combination of snow melts and spring rains without overtopping.
As the report notes, winter drawdowns can also help control nuisance weeds. Exposing aquatic plants to freezing and drying conditions can kill them, and fanwort is one species that is susceptible to this treatment. The report says:
It would enable homeowners to remove leaf litter and other debris from their immediate shorelines, as well as providing access for dock or wall maintenance. Limited drawdowns should provide an added benefit of flushing suspended debris, sediments and nutrients out of the pond and help to preserve water quality.
Drawdowns used to be an annual ritual for Foster's Pond residents. The last drawdown was apparently conducted in 1973, when the level was dropped by about a foot.
The recommended drawdown could be achieved by repairing the "stop logs" in the dam - removable planks which allow the water level to be dropped in stages. The Corporation's plan, approved at the September 2004 meeting, is to implement the drawdown as soon as permission is received from the Town's Conservation Commission - while closely monitoring shallow wells, to ensure that no one loses water. Historically, it appears that drawdowns did not result in water loss when shallow wells predominated around the Pond. Shallow wells would normally be expected to have their intakes at least 3 or 4 feet below the level of the ground water, so that a modest drawdown would not affect them.
Hydroraking
Hydroraking is not recommended for the control of fanwort in the densities we now have in Foster's Pond, although individual homeowners may continue to find the hydrorake useful for removing lilies and muck from their shorelines. Thus, hydroraking will continue to be a part of our integrated management strategy.
Control of nutrient inputs
The Corporation should continue its efforts to educate residents about using phosphate-free dishwashing soaps, phosphate-free clotheswashing detergents, and organic fertilizers. These measures - together with septic system upgrades as homes change ownership and Title V requirements kick in - will keep down the nutrients which fuel algae blooms in the Pond. However, as the report states, "Rooted plants derive the majority of their nutrients from the bottom sediments, which watershed management cannot address." That is why, as the report states, the control of nutrient inputs "will do nothing the control the nuisance fanwort growth." But it is part of a sound integrated management strategy, which includes preservation of water quality.
Learn More
Read the complete report from Aquatic Control Technology. Aquatic Plant Survey and Development of a Nuisance Aquatic Plant Management Plan for Foster's Pond (October, 2004). This is the basis for the Corporation's weed management plan.
Corporation Votes for Weed Study; Biologist Collects Data
August 2004
"That's fanwort," said biologist Marc Bellaud, as he dipped his hand into Foste'r's Pond and pulled out a small, white flower, trailing a couple of feet of delicate, bright-green stem resembling a green test-tube brush.
Bellaud was just starting an afternoon of data collection, the cornerstone of astudy to determine what weeds are clogging the water and what remediation techniques may work.
From the bow of a 12-foot aluminum boat, with an assistant manning the 4HP outboard motor, Bellaud crisscrossed the Pond on August 16, taking soundings, observing weed concentrations, and sampling bottom sediments.
The results of the study, together with recommendations, will be presented to the Corporation in September. The report is critical for any recommendations the Corporation may make to the Andover Conservation Commission, which has jurisdiction to decide what remediation measures may be used in the Pond.
Following an afternoon of sampling, Bellaud found no surprises. He reported that fanwort is the "dominant submerged species - actually, it's the dominant plant overall." Next in order of concentration, said Bellaud, are coontail, bladderwart, and water lilies.
Bellaud hopes to incorporate in his report data on pond depths put together in an earlier study by Weed Committee Co-Chairman David Adilman.
On the recommendation of the Weed Committee, the Corporation voted unanimously at the May, 2004, meeting to fund a study to determine what weeds are in the Pond, and their relative concentration.
The Corporation engaged Aquatic Control Technology, Inc., to perform the study. Bellaud is senior biologist at ACT, which has performed hydro-raking on the Pond since 1992 and has advised the Corporation on past weed-control efforts.
The field work was scheduled to be done in August at the height of the summer weed growth.
Here is ACT's formal description of the scope of the work:
This survey will involve collecting data at sampling points along several transects that will be established in the pond. All sampling points will be recorded with Aquatic Control’s Differential GPS Unit, which is accurate to within one meter. At each sampling point, Aquatic Control will record water depth; bottom type; percent bottom cover for all plants; record and list all plant species observed at the site, in decreasing order of abundance; and assign a biomass value from 0-4 (low to high) based upon height or volume of the plant growth throughout the water column.
Deliverables from this task will be one map showing the distribution and relative cover/biomass of the overall plant assemblages throughout Fosters Pond, including exotic and native plants as well. These maps shall be drawn using Aquatic Control’s ArcView GIS system. The data from each data collection site will also be presented in tabular form to allow for statistical comparison in the future. We will also interpret the data and provide you with a narrative of the conditions in the pond and outline management recommendations complete with cost estimates.
Committee Hears from Expert
At its second meeting, the Foster's Pond Corporation Weed Committee heard a detailed overview of weed control alternatives from one of the foremost experts in the region.
Gerry Smith, president of Aquatic Control Technology, Inc., spent two hours with the committee on December 8, reviewing the cost and effectiveness of a wide range of weed control methods. His company engages in weed control on more than 500 ponds annually in New England and Eastern New York. The company has performed hydroraking for Foster's Pond residents since 1992. The company also sold the FPC a weed harvester which the FPC operated successfully for several years in the 1980's.
One key recommendation Smith made was that the FPC should conduct an aquatic plant survey to identify which weeds are in the pond and where they are
Answering the committee's questions in a lively give-and-take, Smith discussed herbicides, dredging, harvesting, hydroraking, biological controls, and winter drawdowns, providing information on the pros and cons and the cost ranges of each approach. Click here for a 2-page chart of weed control techniques Smith prepared; it lists methods targeting specific plants, how the methods work, concerns relating to each method, and ballpark costs.
This was not be the first time Smith has offered advice to the Foster's Pond Corporation. In 1981, he toured the Pond, examined the weed growth, and met with the FPC committee (then called the Condition of the Pond Committee) which was trying to come up with a weed control program for that era. For a report of the 1981 committee meeting, with its survey of alternative strategies, click here. Smith has also provided advice to the FPC informally over the ensuing years.
The Weed Committee held its first meeting on October 22, reviewing several strategies for dealing with the weed problem in the Pond. There was also discussion of performing a watershed survey, a weed assessment, and a geo-chemical assessment.
The Committee has established an ambitious research agenda, with plans to investigate five pond-restoration alternatives: harvesting, winter draw-down, herbicides, dredging, and grass carp. The Committee hopes to gather information on past and current projects on other ponds (particularly in Massachusetts), and the results and costs of these projects.