Current Pond Conditions

Current Pond Conditions and Treatment Program News

Update 7/31/08
From Mike Lowery of WSQC:
Dudley Pond was treated today with fluridone (liquid Sonar AS) in order to bring concentrations back to 12ppb. Dosage was based on FasTEST samples taken last week indicating concentrations near 7ppb, and now assumed to be about 6ppb.   As before, dosage calculations were done separately by the four 'basins' in FasTEST sampling.

Gerry (ftom ACT) said that in prior years, had he observed the plants in their current state, ACT probably would not have done a booster treatment.   WSWQC's treatment plan calls for maintaining concentrations at 6-7ppb for 100 days. Gerry believes today's booster should carry us to the end of the 100 day treatment period. (The first treatment was 5/9 and 100 days later is 8/17. Based on this year's history, concentrations should be roughly 7ppb on 8/17)

Gerry and I discussed the utility of doing a final dose should we still be seeing new growth at the end of the 100 day period.   We will review the state of the Pond at that time.

Update 7/8/08
Today was the 2nd booster application (the original treatment was 5/9/08, and the last booster was 6/5/08) - we are close to day 60 of the treatment.

During today's treatment ACT:
—Reapplied Sonar PR and Sonar Q pellets at the same locations as previously (the Mansion beach application emphasized left side (from the beach) along Lakeshore Drive, where the surface infestation is worse).

—Raised the concentration of Sonar AS liquid from an average of 5.6ppb (measured by the recent FasTEST) to a calculated 11ppb (the pellets will contribute the last 1ppb).

ACT checked that at their 'deep-hole' spot, the thermocline is still at about 14' (below which there is little fluridone mixing), and measured Secchi depth at about 8'. Temperature and dissolved oxygen readings were taken at one meter depths.

More from Mike Lowery: Today Gerry Smith and Michael Lennon of ACT and I did a visual inspection of the coves and locations were plants with some healthy portions had been spotted.   We covered most of the shoreline, and it is much the same everywhere: The milfoil is still putting out small (1-3") new 'puffs', but the plants as a whole are rubbery - and mostly dying or dead.

This photo shows a full plant on the deck of the air boat, showing these characteristics.

According to Gerry Smith, this is not uncommon and is referred to as 'poodling' - because like the tail of a poodle, it is hairless except for a few puffs along the way. Gerry observed this has happened in prior treatments on Dudley Pond. Gerry is confident that the treatment will be successful.

The underwater 'fields' of plants are still visible from the surface as brownish, denuded plants with occasional green 'tufts' - the bulk of the plants have not yet dropped.

Update 6/20/08
Water samples were taken on 6/12/08, one week after the "booster treatment" of June 5^th. The average concentration of the four samples was 10.05 ppb. The plan is to do more sample testing near the end of June, to determine the dose and timing of an second "booster" in July.

At present, there is still quite a lot of milfoil in the Pond. The plants have stopped growing, and are mostly below the surface, which would not have been the case without the treatment. The plants are not healthy in appearance, and they should begin to fall over and drop out of the water column within the next few weeks.

Update 6/2/08
A "booster treatment" of Sonar is scheduled for Thursday, June 5^th, based on the tests of the water samples taken on May 21^st. The following is from ACT:

The results from samples collected on May 21^st, some 12 days post-treatment from our May 9^th treatment date, average 7.35 ppb. Sonar has a reported half-life in water of "roughly" three weeks, provided there's no water inflow or outflow that would serve to dilute the concentrations further, in addition to Sonar's normal breakdown from exposure to light. This average Fluridone concentration of 7.35 ppb indicates that we were probably close to but a bit shy of our targeted concentration goal of 12 ppb.

As with the first treatment, the pond will be closed on June 5^th for all activity (swimming, fishing, boating) for 24 hours. Normal activity can resume on Friday, June 6^th.

Update 5/27/08
At this time, there is still a fairly large quantity of floating milfoil fragments at the surface, along with some algae and floating tree pollen. The effect of fluridone on milfoil is a slow process: It is expected that the effects of the herbicide will begin to be apparent within the next few weeks. At first, plant growth is slowed then stopped, then the plants become further degraded until they ultimately die off.

Currently, the conditions are:

	There are a few tips above the surface in spots near the outlet and Mansion Beach.
	Growth rate seems to have slowed way down.
	In many areas the top 6-8" is red.
	Its leaning over in spots.
	In the Mansion Beach arm, much of it is covered by algae
	Water clarity remains very good in most places.

Update 5/21/08
ACT was back at the pond today, taking water samples from four different areas of the pond where fluridone was applied. These samples have been sent to SePRO (the manufacturer of Sonar) and the results will be used to determine the amount of fluridone in the next dosing.

Update 5/9/08
The first application of Sonar (fluridone) was done today, by the contractor, Aquatic Control Technologies (ACT), using an airboat. See pictures and video of the application.