Rainbow Lake may get some ‘hydro-raking’

A cove on Rainbow Lake had some muck but fairly clear water when these boys were fishing early May.

A cove on Rainbow Lake had some muck but fairly clear water when these boys were fishing early May.

Macklin Reid / Hearst Connecticut Media

Seeking cleaner, deeper water for a lake that is the visual and recreational centerpiece of their neighborhood, the Ridgefield Lakes Association is working on a plan for the “hydro-raking” of Rainbow Lake — or at least parts of it.

“We just want to remove some of the muck from the lake,” said David Sarath, a member of the Ridgefield Lakes Association board.

“It’s pretty straightforward. The lake is getting older, and a lot of coves are filling in with mostly leaf debris, organic matter that’s built up over the years. Whatever falls into the lake kind of floats along the top and gets caught in the coves.

“Coves that used to be two- or three-feet deep are now a foot deep, six inches even,” Sarath said.

Rainbow Lake — also known as Wataba Lake or Lake Wataba — is man-made. The 44-acre lake was created in the 1920s. Though they are nearly all now used year-round now, many of the houses around Rainbow Lake were originally summer homes.

The lake — which has two small beaches — isn’t that deep.

“It depends on who you talk to,” said Sarath. “Some people say between eight and 10 feet in the really deepest part, but a lot of it is three or four feet.”

“We spend a lot of money every year on herbicides, to prevent the algae from growing, prevent the weeds from growing — a lot of non-native species of weeds,” he said.

“So, our treatment company keeps saying if you can get rid of that stuff, you won’t have to spend as much on herbicides and algaecides.”

Wetlands board

The Ridgefield Lakes Association appeared before the town’s Inland Wetlands Board Thursday night, July 9, seeking a permit for the hydro-raking.

The public hearing was adjourned after it became clear the board wanted more information, including specifics on the area of the lake to be hydro-raked and the areas where the muck would be put to dry out before it is carted away.

“If you could delineate where you’re working, and exactly where the debris is going to be staged, and what kind of equipment will be in there — just maybe more information might be helpful,” said Pat Sesto, the wetlands board chairwoman.

The lakes association is scheduled to return to the Inland Wetlands Board Aug. 27 — although the association president Douglas Carroll kept open the possibility that, if the needed information came together quickly, the association might try to get on the agenda of the board’s July 23 meeting.

Carroll was disappointed, after hiring a soils scientist to do mapping and thinking the association had come into the hearing with all it needed.

“I hope you understand this is such a challenge for us, trying to figure out what you want,” Carroll said.

Expanding project

One source of confusion at the hearing was that the association had hoped to expand the project.

The initial permit request is to remove about 200 cubic yards of material from a cove near 65 Crescent Drive, accessing the lake via the established Crescent Drive Beach.

But Carroll told the board that there was some thinking that once arrangements were made for the hydro-rake to come and clean that cove, individual homeowners — or maybe groups of homeowners who shared stretches of lakefront — might add to the contract and hire the firm to have the lake in front of their properties hydro-raked.

“Our intent is to have homeowners who are members also jump in on this,” he said.

There is an initial fee from bringing the machine to the lake, and the association would cover that cost, and then homeowners who wanted additional areas done would only pay an hourly fee — in essence renting the machine and it’s operator, Sarath later explained.

“I know other people in the neighborhood want to jump in on this. So we’d take this, hopefully approved permit and then add to it, perhaps — does that make sense?” Carroll said to the board.

“I understand how it makes sense from your perspective. It legally does not make sense,” said Sesto.

“...If you are proposing additional activities, it’s important for you to show those on the map, as well. It’s difficult to tentatively approve something that maybe could happen.”

When it became apparent the board was dubious of an more open-ended permit, Carroll said the association would limit this application to the cove near Crescent Beach, and seek a separate application if it sought to hydro-rake other areas as more homeowners sought to take advantage of the machine being there.”

Contractor absent

The board also seemed disappointed that the contractor the association has been talking to about doing the work, SOLitude Lake Management, wasn’t at the hearing to help explain what was proposed.

“My contact with SOLitude, on my board, says SOLitude has no intention of coming before your board,” Carroll said. “We may be able to talk them into it. If they chose not to, would that derail the project?”

“If the questions can be satisfied, that’s what matters,” said Sesto. “Having them be part of the consideration is helpful because they could answer some of the technical questions.”

SOLitude’s website offers this description of the process: “Hydro-raking (mechanical raking) is a widely used and effective technique for selective removal of nuisance, rooted vegetation. The hydro-rake is also used to clear accumulations of unconsolidated bottom sediment and debris (i.e. decaying leaves, peat, etc.).”

Sarath said the machine that’s used is kind of like an excavator that floats on a barge, rather driving around on wheels or caterpillars.

Wetland board member Alan Pilch said he thought a “turbidity curtain” would be needed for the project, to keep what’s stirred up by the work from having too much affect on the water in the rest of the lake.

He also suggested hydro-raking might not be a long-term solution, since the lake would likely begin to return to how it was.

“By next summer it may not be as conducive to swimming or recreation, because things grow back,” Pilch said.

“I’m just trying to figure out what they sold you,” he added.

“They sold us on cost, largely,” said Carroll. “And this is what they told us would be the best solution.”


The Ridgefield Lakes Association has about 120 members — it varies from year to year — and there are about 200 homes in the lake’s “catchment area,” Sarath said.

If the project is approved by the wetlands board and proceeds as envisioned, the cost might be considerable. There’s an initial cost for bringing the machine to the lake, and once it’s there the charge is $250 an hour, Sarath said.

“I think the lake association budget is like $10,000 and we’re hoping the neighbors will kick in another $10,000,” Sarath said. “I’d say $20,000 to $30,000. It’s sort of like a test of the system: How doable it is? How much benefit can you see out of spending that kind of money?”

Still, Sarath said the association board thought the argument for at least trying to remove the debris from the lake was compelling.

“The organic material that’s in the lake is promoting all this algae and weed growth,” he said.

“As it is now, the biggest part of our budget is herbicides,” he said.

The association hires professional lake management firms to do chemical applications “several times a year, half a dozen or more, depending on the conditions,” Sarath said.

The chemical treatments require a permit through the State Department of Energy and Environmental Protection (DEEP)

“it’s all very scientific,” he said.

“Every treatment company we’ve ever hired has told us if you could get some of that out of there, it would benefit the lake tremendously.,” Sarath said.

“The lake is loaded with nutrients, those nutrients are organic material weeds and leaves. The more of those nutrients we can get out of the lake, the less herbicides we need to use to control the weeds,” he said.

Blue-green algae

One of the concerns is what is called blue-green algae — although it isn’t really algae, but cyanobacteria. The bacteria thrives in warm, nutrient-rich water, and some varieties of it produce toxins that are linked to illness in humans and animals.

“Four or five years ago, we had a blue-green algae outbreak, to prevent that has been our biggest goal,” Sarath said.

While other lakes in Connecticut have had problems recently, Rainbow Lake hasn’t, he said.

“Rainbow Lake has not had a blue-green algae outbreak in five years,” Sarath said.

Sarath said he understands that the Inland Wetlands Board — in its first year as a separate agency form the Planning and Zoning Commission — feels a need for specifics and exactness in it’s permitting process.

But he also sees the project as an environmental benefit.

“It’s a win-win,” Sarath said. “We want to remove organic material from the lake — it’s to benefit the wetland, it’s to benefit the lake. It’s to benefit the environment.”