Definition of the Field Pond Watershed

Field Pond was formed in 1933(?) by creating two dams in what is now the South East corner of the pond. (detailed history here would be nice)

The following topological map shows the boundary line of the Field Pond watershed area:

The red line represents the "divide". A drop of water falling inside the red line will end up in Field Pond, and a drop outside will flow to another watershed. To the North, East, and South of the Field Pond watershed is the Skug River watershed, which Field Pond flows into from the sluice gate on the South East dam. The Skug River flows into Martins Pond, which then flows into the Ipswich River and makes it's way to the Atlantic at Crane Beach in Ipswich. So, Field Pond is a part of the Ipswich River watershed.

To the West of the Field Pond watershed the water flows into Foster's Pond, and then on to the Shawsheen River and the Merrimack, which makes its way to the Atlantic at Newburyport (between Salisbury beach and Plum Island).

Here is an old (1893) topological map which shows the area before the dams, before Rt. 125, and before many of the neighborhoods were developed. The red boundary is the watershed area. Note that, while surprising accurate for a map created 100 years before GPS, the contours and roads of the old map don't correspond to the current topo, from which the watershed divide was derived.

And this is a current aerial map of the area:

You can see the difference in foliage in the low areas of the watershed.

The watershed boundary area was determined by using the topological contours and then confirmed by walking the boundary and inspecting the direction of groundwater flow at each low point.

Notice that the area is remarkably small, and (thankfully) devoid of any industry. The most significant chemical threat to the watershed is the runoff from Rt. 125.

History of Pond Treatments

Field Pond has had recent attention from the Massachusetts Dept of Conservation and Recreation (DCR), who have undertaken programs in 2006 and 2008 to control the invasive plant growth. Attached below are various reports and maps which detail these programs. Here is a brief summary:

2006

• Surveyed by Aquatic Control Technology, Inc. who recommended treatment.
• Program to control the widespread and abundant growth of invasive variable watermilfoil and fanwort, which was near contiguous cover.
• Herbicide: Sonar (fluridone) at initial dose of 15-20 ppb (goal: >10 ppb for 90 days)
• Initial treatment on 6/20, then two booster applications on 7/19 and 8/20
• Result: controlled >95% of milfoil and >99% of fanwort
• Post-treatment new plants: moss, stonewort covering most of bottom (this is good). Traces of elodea and thin-leaved pond weed (also desirable).
• Post-treatment casualties: waterlilies and watershield (but they should grow back).
• No reports of fish mortality
• Conclusion: successful control, good for next 2-3 years.
• Recommendation: Spend $5-10K on 'spot management' of milfoil in 2007 with Reward (diquat). Also hand-pull by volunteers as much as possible.

2008

• Surveyed by Aquatic Control Technology, Inc. on 5/30 who recommended treatment.
• Variable watermilfoil was fairly advanced and widespread.
• Overall cover 10-30%, with some areas of dense cover
• No fanwort anywhere.
• Healthy bed of stonewort throughout most of the bottom (good)
• Thin-leafed pondweed (good) predominant in deeper portion near dam
• Recommend: treat entire pond for milfoil with Reward (diquat) in split treatment (14 days apart)
• Treatment was undertaken, but completion report is not yet posted here.

The surveys, treatment, and follow-up reports were all done by Aquatic Control Technology of Sutton, Ma. The cost of each treatment was $20-30K, paid by DCR.

Here are the detailed reports from both the 2006 and 2008 treatments. This is a large file (20MB) so it might take a few minutes to download. When you unzip the file it will put all of the 2006 and 2008 management reports into a folder.

Below are the individual reports. These might not load correctly into acrobat on Windows, but if you save the file to your drive it should then load into acrobat without a problem.

Attachment	Size
2006-aquatic-mgmt-program.pdf	1.19 MB
2006-vegitation-distribution-map.pdf	6.44 MB
2006-interim-report.pdf	1.09 MB
2006-aquatic-mgmt-completion-report.pdf	4.78 MB
2008-survey-and-vegitation-map.pdf	5.19 MB

The DCR Partner Program Grant

A small group from the FPWA have applied to the DCR's partner program to help fund treatment of Field Pond in 2011. DCR has granted FPWA a maximum of $16,000 on a 2:1 match basis, which requires FPWA to raise $8,000. The contribution from the FPWA must be given to the state by 2/28/11. It is expected that it would cost about $24,000 for another treatment.

FPWA must raise its contribution immediately, or the state's contribution will not be available. In addition, the project must be finished by 6/30/11 to be eligible for payment by the state, so this is a 'use it fast or lose it' deal. In order to take advantage of this program, we would need to initiate another survey of the pond, apply for a permit from the conservation commission and MA, and arrange to have the treatment performed by one of three licensed vendors. In order for the treatment to be done in June, the survey and permitting process would have to start by April. This is an ambitious schedule.

Attached below is a scan from a few pages of the DCR booklet: "A Guide to Selected Invasive Non-native Aquatic Species in Massachusetts", which gives a brief overview of milfoil and fanwort.

Attachment	Size
dcr-invasive-plant-book.pdf	6.37 MB

Arguments Against Herbicidal Treatment

Several people have made a strong argument for delaying treatment in 2011 in order to develop a thorough management plan for the pond. The DCR's Generic Environmental Impact Report (GEIR) is clear that the starting point for any intelligent pond management program is a thorough management plan, which we don't have. It makes sense for us to think about the issues at Field Pond with a long term perspective. The treatment program we're on now (ie. the herbicide treatments of 2006 & 2008) requires an expensive (~$25K) reapplication every 2-3 years for as far as the eye can see. The DCR paid the first few, and FPWA would have to contribute 1/3 of the cost of the treatment this year. Future years are uncertain.

Some relevant quotes from the DCR's GEIR (Generic Environmental Impact Report):

page 4-89

An herbicide treatment can be an effective short-term management procedure to produce a rapid reduction in algae or vascular plants for periods of weeks to months. Although long-term effectiveness from herbicide treatments is possible, in most cases herbicide use is considered a short-term control technique.

The use of herbicides to get a major plant nuisance under control is a valid element of long-term management when other means of keeping plant growths under control are then applied. However, failure to apply alternative techniques on a smaller scale once the nuisance has been abated places further herbicide treatments in the cosmetic maintenance category; such techniques tend to have poor cost-benefit ratios over the long-term.

p 4-116 (about Fluridone)

Doses >10 ppb are almost always applied for fanwort control, with doses of 12- 15 ppb showing signs of success and doses near 20 ppb providing nearly complete fanwort kill. Unfortunately, at doses approaching 20 ppb, nearly all other submergent vegetation will be impacted as well.

(The target dose on Field Pond was 15-20ppb)

"The Practical Guide to Lake Management in Massachusetts," (http://www.mass.gov/dcr/watersupply/lakepond/downloads/practical_guide.pdf) which is a companion guide to the GEIR document outlines the various problems encountered in managing lakes including problems with algae (which have to do with phosphorous levels), introduced plant species (invasive plants) such as milfoil, and native plant species which can become “invasive plants” (the water lilies might fit in this category). This guide could be invaluable as we look for alternatives to the chemicals. The “Guide” includes numerous (40+ varieties) "Techniques to Manage Eutrophication and Aquatic Plants." The two chemicals used in previous treatments of Field Pond are discussed – Fluridone on pp. 131-133 and Diquat on pp. 123-124. The advantages and disadvantages of chemical controls are outlined in Table 4 on page 36. Also important to look at are the seven “Axioms for the Control of Rooted Plants in Lakes” on pp. 22-23. Those axioms could be the basis of a plan.

Fanwort may be "native" to this country, but the way it has taken over certain ponds has put it in the "invasive" category. Fanwort infestation was apparently the motivating issue for the application of chemicals at Fosters Pond. ( http://www.fosterspond.com) Reading the steps they have taken to manage that pond is very interesting. They have used, and apparently plan to continue to use, herbicides to control some of the invasive plants, but in addition they have a well-thought out plan of control that includes education and information about the use of fertilizers and detergents and signs to make recreational users aware of the potential for bringing in invasives on their boats and clothing. They also have a "winter drawdown" and individual homeowners use techniques such a "hydro-raking." Fosters Pond differs from our situation as it is not a state pond. Also, we are not looking to have a "beach" in our back yard, only a nice, fertile, pond welcoming to wildlife, canoeing, and walking around.

One more caution about using chemical treatment is that the FPWA doesn't represent the broader population which has a valid interest in the pond as a public natural resource. Those who strongly object to the use of chemicals may hold the FPWA accountable for their use if we are the ones who drive the process. If the DCR were to drive the process then the FPWA is only one of the interested parties.

Questions

This page lists some questions that we should attempt to answer in the process of creating a management plan:

What is the likely progression of milfoil in FP if no action is taken? Is it most likely to continue to grow rapidly until dense mats cover much of the surface? If so, how long will this take? Or, will it reach an equilibrium far short of that, where most of the growth is sub-surface and mats are only seen in a few shallow areas?

If we don't do anything, will we hit a "point of no return" in which it will become much more difficult to restore the pond to a reasonable level of milfoil, perhaps because it becomes prohibitively expensive to do so. Or, would the anticipated dose of Sonar or whatever other herbicide is used work even if there were twice the level of weeds in the pond?

Are there natural cycles in the growth of milfoil such that there will be good years and bad years? In the years in which it doesn't grow well, would it return to early-2000 levels?

How critical is it to control milfoil in Collins and Brackett ponds in order to control it in Field Pond?

Can we leave significant portions of FP untreated without hampering efforts to control milfoil in the main areas?

How much could road salt be affecting the growth of milfoil?

If milfoil were eradicated, how likely is it that another invasive take its place creating a bigger problem?