Lake Fairlee Dam Project on Hold

[this article was published in the Valley News and is excerpted here for private use only]

By Maggie Cassidy, Valley News Staff Writer

Friday, July 24, 2015, (Published in print: Saturday, July 25, 2015)

Contractor Parts Ways After Dispute

Thetford — The long-planned project to replace the ailing Lake Fairlee Dam this summer abruptly halted this week after the contractor and the three towns involved — Thetford, Fairlee and West Fairlee — parted ways over a dispute about the unsigned construction contract.

Speaking for the towns, Fairlee Selectboard Chairman Frank J. Barrett Jr. said the $850,000 project, which voters in the three towns approved through bond votes in May, would go back out to bid next year.

This winter, the towns plan to sandbag the dam, which is located in Thetford and controls Lake Fairlee’s shoreline, he said.

[ . . . ]

You are invited to read the rest of this longish article HERE.  The Valley News encourages you to visit their website, where everyone can read one article for free, and up to five per month at no cost by providing an email address.


Where We Treated in 2015, and Why

Chemical control of Eurasian milfoil is strictly regulated by the State.  According to the conditions of our permit we are allowed to apply triclopyr only to those “portions of the lake where EWM is too abundant (moderate to dense) to be cost-effectively managed using non-chemical techniques and is highly susceptible to fragmentation and continued spread.”  The state determines those locations based on the required quantitative aquatic plant survey from the previous fall.  Here are the results of that survey.  Red dots indicate dense milfoil, yellow is moderate, green is sparse, and empty circles indicate no milfoil found at that location.

2014 fall survey map

Click on map for larger image

These surveys are designed to take statistically accurate samples.  They do not report every instance of observed milfoil.  Rather they collect plant samples from a predetermined grid of locations and observe all the species present.  This allows the State (and us) to measure long term changes on all plant populations in the lake, to preclude unanticipated effects of the herbicide use.

Here are the results of the pre-treatment survey done this May.  For this survey every instance of observed milfoil was recorded.  Again, red circles are dense patches, etc.  This map also shows the areas approved for herbicide application.  For the most part they coincide with many of the densest growths of milfoil.

spring survey

Click on map for larger image

The herbicide was applied in the indicated areas on Tuesday, June 16th.  Note that not every location where there is milfoil was treated.  To those (including the author) whose littoral zone contains milfoil but was not treated, we offer apologies and hope that you understand the constraints under which these treatments are done.  We understand that there are divers who are experienced with Eurasian milfoil removal who can be hired to clear it from your shoreline.

More about the Herbicide Application

renovate otfThe herbicide is delivered in 40 pound bags that look like they might contain fertilizer.  Although we are only putting a very little bit of chemical in the water, we want it to be absorbed at or near the roots of the plants so far as possible.  So the chemical comes blended in pellets of chunks of clay, which will sink to the bottom before dissolving and releasing their active ingredient.

P1050350_SnapseedIt is poured into hoppers on the back of the boat.  Under each of these there is a powered spinning disk that spreads the pellets several yards either side of the boat.  (click on the thumbnail to enlarge)  The driver follows a programmed course that zigs and zags back and forth to cover the designated treatment area.  And the speed of the boat and the hoppers’ flow rates are regulated to ensure that the herbicide is delivered at the desired concentration.

Dam Vote Passes — Construction to Proceed this Summer

On May 19th the towns of Fairlee, Thetford, and West Fairlee each approved ballot measures which will allow them to proceed with the rebuilding of the Lake Fairlee dam this summer.  The measures were supported by 76% of the voters in Fairlee, by 78% in Thetford, and by 85% in West Fairlee.  This result is most gratifying to those of us who have devoted many hours over the past three years learning what could be done for the dam and developing a plan to bring it about.  It also represents a welcome level of cooperation among the three towns that we hope can be replicated in other areas.

The contractor is set to begin work on the dam sometime in mid June.  Recreational use of the lake should not be affected at all.  In the near future each town will select delegates to the new Tri-Town Commission which will take over responsibility for the dam in the future.  We will keep you advised of our progress.

Thank you to all who helped make this happen.  Today’s decisions are a victory for our lake’s ecosystem, for fiscal sustainability, and for common sense.


Milfoil Density Map for Herbicide Treatment

click above for larger

click above for larger

The conditions of our State issued Aquatic Nuisance Control Permit only allows us to apply the herbicide where the milfoil growth is moderate or dense.  The attached map reflects data collected last September, but conditions probably have not changed significantly since then.  Another survey has been completed in the past week.  Those results will govern the treatment locations on June 16th.  We will share them here when we can.

Herbicide Treatment Scheduled for Tuesday, June 16th

Due to the harsh winter and late ice-out in the northeast, the plant growth in the lakes behind previous years. As we know, the Milfoil must be growing for the herbicide treatment to be effective. We had previously had a soft treatment date of June 8, 2015 however that is now not an option. Our treatment contractor is moving the treatment date back a week to 6/16/15 in order to have the best efficacy as possible. The more growth of the Milfoil, the more effective the treatment. The lake will be surveyed in the coming days to confirm.

We apologize for any inconvenience this may cause however it is in all of our best interest for the treatment not to fail.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

As with previous treatments, the lake will be closed to all uses for the day of the treatment and the day following.  On Thursday June 18th recreational use may resume.  This includes swimming, boating, fishing, etc.  We recommend not using lake water to irrigate your lawn for several weeks, however.  The herbicide (triclopyr) is a plant hormone which is very safe for us (humans, pets, etc) but toxic to certain kinds of plants.

Details of our Herbicide Treatment Permit

The State of Vermont is very strict about the release of chemicals in the environment.  Our use of triclopyr is subject to a long list of conditions and restrictions that are enumerated in the permit issued to us earlier this week.  The application process is exhaustive, and approvals have to be obtained from the Department of Health and the Department of Fish and Wildlife before the final permit is issued by the Lakes & Ponds Management and Protection Program of the Department of Environmental Conservation.  Yes, we get to learn quite a bit about navigating the State’s bureaucracy along the way.

permit final

Click on image above to view document


How Safe is Triclopyr?

We have made the decision to again treat Lake Fairlee with the herbicide triclopyr (Renovate™).  Based on our experience with this chemical in 2010 and 2013 we believe this to be a safe and effective way to deal with the growth of Eurasian milfoil in our lake. At that time we did as much research as we could to reassure ourselves that what we were doing would not have any harmful effects.  You can see what we found then on the page called Herbicide Resources.

Can the chemical get into my well water?

Property owners who have wells near the lake, particularly shallow wells, have experssed concern for the safety of their drinking water supply.  The State of Washington’s Department of Health has looked at this question, and found:

“The limited mobility of triclopyr in soil, low absorption constant, and high rate of microbial and photolytic degradation in water and sediment would indicate that this compound would have little potential for the extensive mobility required to contaminate groundwater supplies.”

They go on to note that:

“This assumption is supported by data collected by the US Geological Survey (USGS), as this federal agency has collected over 850 groundwater samples over a five-year period in the Pacific Northwest area and these samples have been examined for pesticide residues. Triclopyr has never been detected in any of the groundwater samples taken by the USGS, despite extensive use as an herbicide in this region in forestry applications over a 20-year timeframe.”

We only know of one published instance of well water being tested for triclopyr after an adjacent lake was treated.  In this case the level detected was 0.0 ppb after two weeks.

 How do we know it is safe?

Triclopyr is a manmade chemical that does not occur naturally.  Although it has been used for more than three decades without any recorded incidents, how can we know that it never will?  It is hard to prove a negative.

Knowledge is power, and in this case we believe that understanding more about what triclopyr is and how it works can inform our belief in its safety for this use.

Auxins are a class of plant growth hormones.  They are involved in the regulation of the growth of plant cells.  They are directly responsible for phototropism, the tendency for a plant to grow towards the sun.  A simplified version of the way this works is that within a given cell the auxins are inhibited by sunlight, so the growth occurs more at the end of each cell that is not exposed to sunlight, and the whole plant appears to reach towards the sunlight.

A little about auxins

Chemical formula for triclopyr

Triclopyr is a synthetic chemical called an auxin. Auxins are a class of chemicals found in plants that help regulate their growth. For example, phototropism is caused by inhibition of auxins by sunlight, so that the shaded underside of the plant grows more than the sunny part, causing the plant to ‘grow toward the sun.’  Abnormal amounts of these auxins can disrupt the normal growth of a plant, even kill it, so auxins are also used as herbicides.  Also, different species of plants respond differently to auxins, making them useful for weed control. Finally, triclopyr is an effective herbicide for dicots(flowering plants and trees) but not for monocots (grasses and conifers).  More information HERE.



Tri-Town Committee Hosts Dam Meeting

About 50 people turned out on a fine Saturday afternoon to hear the latest plans for the repair of the Lake Fairlee dam.   Members of the Tri-Town Committee  spoke on a panel for about 45 minutes, then answered questions and heard discussion for about the same period.  Although the meeting had been publicized on the three towns’ listservs most of the attendees seemed to be residents from around the lake and other friends of the Lake Fairlee Association.  Three additional meetings will be held in the fall, one in each of the three towns, which will cover the same material and hopefully attract a wider audience.

569        570
  Jay Barrett, Fairlee Selectboard member, spoke about the importance of the lake to the community, mentioning some intangible and less easily quantified benefits.  The lake attracts visitors who support local businesses.  The lake is a source of recreation and relaxation for local residents.  He explained how the three towns had come together around their shared interest in preserving the lake, and had formed the Tri-Town Committee.  He gave an overview of the committee’s process to date, and the committee’s decision to complete the planning and bidding process before bringing a finished proposal  to the voters at Town Meeting next March.

Shawn Patenaude spoke next. He is an engineer working for Dubois & King, a consulting firm which has been engaged to examine the condition of the dam and develop plans for its repair.  He related his firm’s involvement, and described some of the testing and analysis they had done.  He brought drawings of the planned “replacement in place” of the dam, and explained how this method of repair would involve less permitting.  He explained how the State of Vermont would likely not allow replacement of a failed dam if the permit applications had not been filed by the time the dam breached.  He spoke about the “Phase II” planning which is beginning now that will result in completed plans which can be part of a request for bids.

Donn Downey, a member of Thetford’s Selectboard, gave a thorough analysis of the comparative costs to the towns of allowing the dam to fail, on the one hand, versus passing a bond issue to repair the dam.  If the dam fails, the value of lakeshore properties will drop, as will the property tax income of the towns from those properties.  This decrease in tax revenue will have to be made up by increasing the tax rate of all the properties in the towns.  He used a cost figure of $750,000 for the completed project, and assumed that the towns might issue bonds to be repaid at 4% interest over 20 years.  Based on what he believes are conservative estimates, it will be less expensive for the towns, and for their taxpayers, to fix the dam now before it fails than allowing it to fail and then suffering the shortfall.

final slide

One slide from Downey’s presentation showing annual tax increases

Skip Brown, the Chairman of the committee, spoke briefly about some  legal considerations.  It is proposed that the towns will enter into a so-called interlocal agreement, by which they will agree to cooperate in the rebuilding and subsequent care of the dam.  This agreement will include the creation of a Tri-Town Commission, an appointive municipal board that will oversee the process.  The three towns will acquire an ownership interest in the dam prior to any work being done.

The floor was then open to questions.  They were many and varied.  A few offered suggestions of alternative locations for the dam, or innovative construction methods.  Most of these had already been explored by the committee. Several questions involved the problem of private benefit from public funds.  In order to rebuild the dam, the camp that sits over it will have to be raised up before the work and then lowered back down afterwards.  Through its permitting process the State will require us to return the camp to a sturdier foundation than the one it now sits on.  This will confer a benefit on the landowner at public cost.  Brown explained that the committee had explored various alternatives, and that the one proposed seems to be the most efficient and cost effective.  There were also several comments about the thoroughness of the committee’s presentation and gratitude for its work.