Action On Uncle Harvey's Pond Wrapped Up In Alum Treatment Debate

By: Ed Maroney

Topics: Waterways

Orleans Conservation Trust land abuts Uncle Harvey's Pond.  FILE PHOTO

ORLEANS Everyone agrees that Uncle Harvey's Pond needs help, but there are several opinions on how to restore its health.

Last week, marine and fresh water quality committee chair Carolyn Kennedy presented an environmental assessment of the freshwater pond's status and a proposed management plan. She told selectmen of “a series of toxic blue-green algae and cyanobacteria outbreaks over the last several years” at Uncle Harvey's. “A high level of nutrients was found there,” she said.

“The neurotoxins produced can be deadly.” Kennedy said, citing a recent study based on satellite and drone images of sections of New England and New York that “found widespread areas of cyanobacteria and clusters of ALS,” better known as Lou Gehrig's Disease.

The environmental assessment, done by the Coastal Systems Group of the School for Marine Science and Technology at UMass Dartmouth, found two primary sources of algae-encouraging inputs to the pond: nutrients released from sediments already present (67 percent of the total) and others delivered via groundwater (26 percent). “The major problem,” Kennedy said, “is what's at the bottom of the pond.”

And so, “with great concern for the residents of the town, and the ecological health of the pond, the committee voted to recommend alum treatment to reduce nitrogen loading coming out of the sediments,” Kennedy said, along with, among others, a recommendation that shoreside homes be connected to the proposed Meetinghouse Pond sewer system. The committee also looked at pond aeration, or oxygenation, as another option if alum was not approved.

Introduction of alum in the deepest part of the pond, about four acres, would “significantly reduce the amount of phosphorus available to plant growth,” said Kennedy, who noted that the treatment has been used “in at least 10 ponds” on the Cape, including at Nickerson State Park in Brewster.

“We realize all of these recommendations may not be digestible to everybody,” Kennedy said; other proposals include an education plan for abutters regarding landscape management and further efforts by the department of public works to manage stormwater runoff. The committee found dredging the pond would “cost 10 times more” than alum treatments and that oxygenation would require operating a mechanical system six months of the year “forever. It does not resolve the problem.”

Before Kennedy's presentation, Uncle Harvey's abutter Lou Morongell spoke during public comment against using alum. He said there are few long-term studies of its effects, and its use amounts to “sweeping under the rug the real issues that are causing these ponds and lakes to turn eutrophic and nasty.” He disagreed with scientists' findings that an alum treatment can deliver benefits for up to 20 years, saying that most do so for no more than five years and sometimes less.

“Over a long period of use, alum could become a serious threat to the water quality of our ponds and our health,” he said.

In an email to The Chronicle after the meeting, pond abutter Betsy Furtney wrote that “once alum has settled on the bottom of the pond it becomes insoluble and part of the sediment and is not a contaminant.” Writing not in her capacity as a member of the marine and fresh water quality committee but as a private citizen, Furtney cited scientific studies and state Department of Environmental Protection guidelines to support her position.

Selectman Kevin Galligan pointed to a practical problem, noting that an alum treatment “would require all abutters to be on board,” clearly not the case with Uncle Harvey's. “We have to be honest,” he said. “If that can't happen, I want to help this pond. I just don't think this will get out of the gate. Do we try in the interim aeration and learn from that? The idea is to get the damn sediments out of that pond.”

For selectmen Mark Mathison and Mefford Runyon, dredging is an option of interest.

“There is a charge being developed to create a dredging committee,” Runyon said. “The fresh water group will have a seat at that table. It may turn out to be incredibly expensive, but it may be the best solution to getting rid of the build-up of sediments in the bottom of the pond.”

Mathison said a dredge “that is trailerable and transportable all over town, whether salt water or fresh water,” could be “a valuable asset to the town...When you start looking at what we could do to the ponds so desperately in need of action and factor that in, the overall cost to the town of owning a dredge starts to make sense.”

But, in her post-meeting email, Furtney pointed again to the DEP's lake management handbook, in which “you can read the section on wet dredging and gain an understanding of the size of the dewatering area that would be required near the pond as well as the extensive permitting required, up to and including the Army Corps of Engineers to move forward. That's why it is 10 times more expensive than alum.”

Furtney wrote that she has asked Selectmen Chairman Alan McClennen to hold another session on the issue in November with abutters, the scientists who prepared the report to the committee, and other experts that some who live around the pond would like to invite. At last week's meeting, Kennedy said the best time for an application to the pond is early spring.

McClennen says the town should proceed with caution.

“Clearly, we have to develop a strategy to deal with Uncle Harvey's Pond and other fresh water ponds,” he said at the Sept. 26 meeting. “There are certain things that can be done in the shorter term in making a final decision on dredging or alum...You note aeration appears to be more expensive. Aeration is not a final decision, alum is. When you decide to put in alum, it's forever. We need to be very careful before we do (the first pond).

“The work done to date is fantastic, but you also recommend thinking about adaptive management. We've got money to continue monitoring, then a pondside education program...We have recognized that 67 percent of the problem is the phosphorous in the bottom. It's too late to solve that problem without some more drastic action. I hope we can focus on things that will make a difference before we make a final decision to do something forever.”