Lake Currents – August 2012

by | Aug 29, 2012 | Newsletter | 0 comments

Dear GLA members and Friends,

A lot of news to cover since our last newsletter as your representatives have been very busy trying to coordinate botanical fieldwork, preparation of the Notice of Intent (NOI) and the Resource Management Plan (RMP). We are beginning to look towards the Community Preservation Act as a source for financing the treatment of our lakes next spring. We are going to continue building the awareness of the lake’s demise by having a booth at Grotonfest on September 22nd and by hosting free boat tours from Grotonwood’s beach on September 29th. Many of you have volunteered to help us and we are very grateful.

Conservation Commission Tours Lakes
In July, GLA President Art Prest hosted a boat tour of the lakes for the Conservation Commission ably assisted by Paul Markham piloting his boat and John Diezemann, former GLA President, serving as botanical guide. By all accounts this tour was successful and vividly demonstrated to the commissioners the extent of the problem. We hope they will be supportive when they evaluate the NOI, RMP and the DNA analysis from the botanical field work.

Botanical Survey by Professional Botanist and State Botanist
A few days following this tour, Josh Sulman a botanist with a specialty in the genera Sparganium arrived from Wisconsin to begin his survey of both Knops Pond and Lost Lake. Josh was hired by GLA to once and for all determine if the endangered species, Sparganium natans exists in our lakes. His fieldwork is wrapped around a DNA study funded in part by Natural Heritage (NH) to make this determination. Josh was easily certified to work as a botanist in Massachusetts by NH. Over two days, July 24-25th both lakes were thoroughly surveyed and samples collected. He was joined by Bryan Connolly on July 25th to collect samples in Knops Pond.

Simultaneously, two Wisconsin botanists were collecting samples of Sparganium natans and shipping them to the DNA lab. This plant is not endangered in Wisconsin. These botanists were contacted by GLA and volunteered their services. Thanks go to Susan Knight and Steve Garske.

The DNA analysis will look at all these samples and arrive at a DNA profile for Sp natans. The plants in our lakes cannot be visually identified because they have no fruit or flowers. This was the identical problem last year when four botanists could not definitively identify them.
If a positive identification is made, we can fairly easily shield these plants before treatment of the invasive weeds. We are awaiting the final report.

NOI and RMP have been completed
Our consultant Aquatic Control Technology has completed the NOI application. The Resource Management Plan has also been finished and is available to anyone who wishes a copy. There were many who contributed to this project and we thank them all. These reports will be submitted together with the final botanical and DNA report hopefully very soon. It is now time to turn our attention to financing this project.

The Herbicide Sonar
For over twenty years the GLA and its counterparts have been trying to stop the increasing infestation of non-native weeds that threaten the health of the lakes, their recreational potential, the safety of its residents, their quality as a Zone II water resource and the property values along its shoreline. Every conceivable method that was technically, legally and economically feasible has been tried including hydro raking, benthic barriers, drawdown and mechanical weed harvesting. None of these methods has succeeded except for the use of an herbicide in 2002-2004.

As a result of our past experiences we have developed a Notice of Intent (NOI) that will be filed with the Groton Selectmen that is based on a plan to use the herbicide Sonar to kill the non-native invasive weeds that are destroying our lakes and ponds. Sonar has been approved by the EPA since 1986 and is used extensively by at least twenty- one towns on twenty three lakes/ponds in eastern Massachusetts (see Excel chart below for a list of towns and lakes that we know about that are using Sonar). The list of local towns using Sonar includes Littleton (on a primary water resource), Ayer, Chelmsford, Westford, Shirley, Lunenburg, Wayland and Concord.

Sonar (a.i. fluridone) is selective and does not kill all aquatic plants. As an example in June of 2012 Sonar was applied to Flanagan’s Pond (next to Sandy Pond which was treated with Sonar years ago) in Ayer and while milfoil and fanwort are dying many of the native aquatic plants such as the lily pads and arrowhead are doing fine. In cases where lily pads and native aquatic plants are impacted they typically recover in about a year as they have in Sandy Pond in Ayer. Sonar acts by being absorbed through leaves, shoots and roots of susceptible plants and destroys the plant by interfering with its ability to make and use food. Specifically, Sonar inhibits carotenoid synthesis, a process that is unique to plants. Sonar is slow acting and thus does not cause a reduction in dissolved oxygen levels and thus does not cause fish kills.
According to the EPA the No Observed Effect Level (NOEL) for Sonar is 150 parts per billion (ppb) in potable water supplies. As an example a 154 pound adult would have to drink over 1,000 gallons – a child over 285 gallons – of water daily , containing the maximum 150 ppb legally allowable concentration of Sonar in potable water for a significant portion of their lifetime to receive a dose equivalent to the NOEL. Since most adults drink less than two quarts of water per day their margin of safety would be 2,000 times below the NOEL.

Two other examples include an adult swimmer would have to swim 24 hours per day for over 57 years to receive an amount equal to the NOEL, and adults would have to consume over 2,400 pounds of fish daily for a significant portion of their lifetime to receive the dose equal to the NOEL.

The concentration of Sonar to be used in Lost Lake & Knops Pond is about 20 ppb well below (about 7.5 times below) the allowable EPA concentration of 150 ppb. At 20 ppb or less Sonar can be used at potable water intakes. Testing for residues of Sonar in well water in both public and private wells has been done on Spectacle Pond in Ayer and on Neponset Reservoir in Foxborough. In all cases no Sonar was detected in any of the wells. People who wish to avoid even minimal concentrations of Sonar can do so by filtering their drinking water with a charcoal-based filter.

With respect to toxicity when used at the EPA concentration limits, Sonar does not adversely affect humans, animals, birds, earthworms, honey bees, fish, and invertebrates. There is no fishing or swimming restrictions associated with Sonar treatments. Water treated with Sonar should not be used for irrigation purposes.

Sonar was not found to be an acute poison, chronic toxicant, chemical irritant, carcinogen, teratogen or mutagen. Sonar disappears from the aquatic environment due to photo degradation from sunlight, plant uptake and hydrosoil adsorption. As Sonar is released from the hydrosoil it is photo degraded. Sonar residues in the hydrosoil typically decline to a non-detectable level after 16 to 52 weeks.

Over time Sonar breaks down to carbon, hydrogen, oxygen, nitrogen and fluorine. Sonar is comprised of fluridone plus inactive ingredients that include propylene glycol (a compound used in facial creams), wetting agents, dispersants and thickeners. None of the inert ingredients in Sonar formulations are on the USEPA’s list of “Inerts of Toxicological Concern” or list of “Potentially Toxic Inerts/High Priority for Testing”.

We have concluded that the only economical and environmentally sound method to cope with the non-native invasive weeds in Knops Pond and Lost Lake is to use the herbicide Sonar. It has a proven effective and safe record of keeping in check invasive weeds without harming the ecosystem. Sonar has passed the rigorous standards set by EPA and the even more restrictive examination by the State of Massachusetts as a tool in preserving and protecting our native habitats and wildlife diversity at our ponds and lakes. Numerous towns in and around Groton have successfully used this herbicide without any harm to the food chain from humans down to the tiny invertebrates that support wildlife.

Community Preservation Funds
The Community Preservation Act established twelve years ago imposes a property tax surcharge of 3% matched by State funds to support affordable housing, open space, historic preservation and recreation projects. New legislation has given communities more flexibility in how they can use these funds. This change makes our lake restoration project eligible for such funding. And it may also be a way to re-open Sargisson Beach!
The Community Preservation Committee (CPC) in town will be speaking to members of the Great Ponds Advisory Committee (GPAC) in September about these changes. The GLA must now begin to prepare an application for submittal by November to be in the pipeline for funding by the spring of 2013. These funds, however, will not be available in time for paying our consultant, Aquatic Control Technology (ACT), next April, but the CPC will reimburse any expenditure we made.

Of course, no funds will be forthcoming if we don’t have an approved project. One step at a time. The GLA will take up this topic at its next meeting as we begin to move towards a crucial stage in this long process towards restoring our lakes.

Public Boat Launch
Thanks go to Erich Garger for contacting the local representative in charge of public access. A new kiosk has been placed adjacent to the boat ramp with information for boaters about cleaning off before and after they launch. The problem is there is no way to enforce these rules. The GLA has to actively support legislation (that is supposedly pending) otherwise the problem will persist. It is now pretty clear that the boat launch is the main source for these non-native invasive weeds both entering and exiting the lake. We need more volunteers for this project. Please step up!

Grotonfest Booth for GLA
On September 22, 2012 the GLA will be manning a booth near the concessions. We hope to have Art Prest’s video of the weeds in the lake and photos taken by a lake resident showing the beauty of the ponds on display. We hope to also have T-shirts, hoodies and caps with a GLA logo. Finally, we will be signing up residents for free boat rides on September 29, 2012 from Grotonwood. We are calling the event “Meet the Lakes Day.” We thank Marty O’Bryan for all her efforts in these matters.

Meet the Lakes Day Saturday, September 29, 2012, 10AM-3PM (Rain date September 30th)
Many volunteers are putting together flyers and newspaper announcements. We have four pontoon boat captains so far and could probably use a couple more as standbys in case we have a big response. Please contact me directly at if you can help out. Other volunteers will register residents at Grotonwood’s parking lot, escort them to boats and help them board. There will be a tour guide with each boat discussing the lake, its history and issues, as they travel around. The Selectmen have been invited. Wave when you see the armada go by that day.

Aerial Map of 2011 Water Chestnut Location
A recent search of this area found no sign of this plant, but a mudflat was spotted nearby amongst a large patch of lily pads and other weeds. The mudflat had wild fowl feathers and their droppings all over it. It lends credence that this plant may have been brought in by birds. A kayak or canoe is the best means for exploring this area. I hope everyone will keep their eyes peeled. We hope to soon place a marker where these plants were originally spotted.

Groton Conservation Trust’s Island Ownership
There are two islands in Knops Pond owned by the Groton Conservation Trust (GCT) and two in Lost Lake opposite Grotonwood. The latter two have sustained vegetative and erosional damage due to misuse and overuse by boaters. The GCT wants residents to enjoy these islands, but to take responsible care in their use. Signage will be prepared disallowing fires, food and drink and docking on the islands. We hope to repair the damage on the larger of the two Lost Lake islands and place docking posts, so that boats will not impact the islands directly. To that end, GCT is looking for Eagle Scout candidates who may want to be involved in such a conservation project. Many of you have sons or know others who may be reaching that age and in search of a project to attain the Eagle Scout level. Please contact me at with any such information.

Dr. Bill Eger
Dr. Bill Eger who lives on Knops Pond, turned 90 in March! He and his late wife Marjorie or Jo as she was known to all, worked very hard over the years to preserve and protect our lakes. Jo was heavily involved in a precursor to the GLA and headed a search committee that selected Baystate Environmental to conduct one of the most comprehensive studies of our lakes. Bill was chairman of the Great Pond Advisory Committee for a number of years and led the effort to eliminate milfoil from our lakes from 2002-2004. Bill applauds the work we are doing and is fully supportive of our efforts in 2012. We all owe him our gratitude for all his spirited and diligent hard work. I am sure he would love to hear from you. His phone number is 978-448-5683. Our heartfelt congratulations, Bill, for reaching this plateau. May you continue to be our neighbor and friend for many years to come.

This newsletter was a combined effort of Art Prest and Alex Woodle
Respectfully submitted to the GLA membership and its friends and supporters