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.
2007 Weed Program In Action
Report: Channel Is Fanwort-Free, But Not Main Pond
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?
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&nbs
