Hennessey updates see pushback

The design team at Stantec met with about 40 residents last Wednesday at the Norwood Senior Center for the 75 percent design meeting on the proposed Hennessey Field detention basin.

The project has sparked some controversy, as some neighbors contend the area holds protected species and water features – like salamanders and monarch butterflies, as well as vernal pools – which would be lost if turned into a detention basin.

Norwood Town Engineer and Department of Public Works Director Mark Ryan said the plan is part of a $40-million-plus prescription for water issues in Town known as the Meadowbrook Drainage Study that was originally put forth in the mid 2000s (about $8 million then, the costs have ballooned and will likely still increase since the $40 million number is a couple of years old).

Hennessey’s design is being funded completely by federal funds, and Ryan said they would be seeking more state and federal funds to help Norwood pay for it if the Town decides to move forward.

The plan, according to Stantec Geotech Engineer Stephen Karpenko, is to basically put the site back to where it was before a drainage culvert put the associated stream underground. He showed a map of the stream systems from the 1930s, before Norwood was as developed as it is now.

“Where those current stormwater drain pipes are now running through Hennessey Field was an original creek channel there, and this project is restoring that creek channel there by daylighting the stormwater pipe at the northern end,” he said. “You can already see if you go out there today that there is some water that runs through there as a natural path. We just wanted to show you that this is restoring the original channel through Hennessey Field.”

Stantec Senior Associate Water Planning Engineer Stefani Harrison said there isn’t really a better location for this water storage. She said this basin collects water from essentially the Downtown and central area of Town – simply by accidents of geography and elevation providing the downhill power to do so – and brings it to Meadowbrook (which also saw some upgrades recently), which then flows the water out through the Neponset River.

But she pointed to recent flooding events like the June 2020 flood that inundated many areas in the basin and said they are unlikely to remain isolated flooding events.

“We did a technical study to understand how to best manage flooding in key neighborhoods that are subject to repeated flooding,” she said, pointing to a computer predictive model that used rain data and pipe-flow data recently collected. She said they ran the computer model against collected data and found that the model mirrored real-life data.

“So then we can take this model we think is doing a reasonable job of representing flow in the underground system and apply different designed storms,” she said. “We simulated these large storms and we looked at what kinds of projects in the drain system would it take to manage flooding in these key neighborhoods that are vulnerable to flooding. What we came up with was a series of projects, which will take the floodwater out of the neighborhoods.”

Harrison said the best way to do that is to store some of the water – six million gallons in this project’s case – so that the current pipes can get the water out before it spills over into the neighborhoods.

“So places like Pleasant Park and Hennessey Field were considered for this purpose, and Hennessey Field is ideally suited,” she said. “It already has a lot of flood flow coming through it and it has a natural bowl shape.”

The detention basin, according to Karpenko, would drain out several hours or a day after a big rain event, if it doesn’t overflow into its spillway. During normal operation, it would be either a small running stream or dry stream bed. He said it would handle storms up to a 10-year storm without using the spillway.

Residents were concerned about blasting during construction, and Karpenko said they would follow all state-required procedures for such blasting, which includes allowing residents within a certain area to ask them to come in and take pictures of their foundations before and after blasting. That would ensure if there is any damage to residents’ foundations that the company pay for it. Residents asked that a horn or some kind of warning be sounded before blasting take place, and Karpenko said they would consider it.

Another concern was wildlife protection. Resident Anne Mackiewicz said she wanted an independent wildlife study conducted, as she believes there are several species in there that might upset the detention basin plans.

“Independent of you people, I’ve spent two or three hours on the phone with Mass Wildlife explaining what we’re looking for, and they said they can’t do that, we need to fund an independent certified Massachusetts botanist,” she said. “There is a species (of butterfly) called the frosted elfin that relies on Hennessey’s habitat. I have seen that butterfly down there, it’s an endangered species, which is why we want someone independent of this Board and consultant to go down there… I’m convinced there is a vernal pool there. There is scrub oak there, which certain species need to survive.”

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Ryan said Town Meeting would be the appropriate body to approve such a venture.

Selectman Michael Saad said he feels the cost of the project – estimated at around $8 million-$10 million at this point – would be too expensive with not enough return.

“We’re taking down open space for a retention pond (sic) and we don’t know if that retention pond is going to work,” he said. “This is like $100 million risk, and these people don’t deserve that. If you people can guarantee it, and put your name and company on the line that this will work 100 percent, that’s a different story. But now? There is no work I’ve seen that says it will work in a big storm. I’m not sure the Town can take it in the (water) enterprise fund… And the cost of it, I don’t think is justified.”

Ryan reiterated that the 2022/2023 estimate for the entire slate of the Meadowbrook Drainage projects was estimated at $40 million, and he didn’t know where the $100 million came from.

“The $100 million number Mr. Saad mentioned, we have this in Capital Outlay for $10 million, and I’m not sure where that $100 million came from,” he said.

The project, at least when it was originally pitched, is supposed to be one piece of the Meadowbrook Drainage Study area designed to slow water and stop flooding in the area. Harrison and many others said the Town can’t increase the rate of water flow out of the Town and impact other areas downstream, so the Town has to slow its water flow with detention facilities, and this is just one of a $40 million series planned for the Town – https://gvimes.link/hennessey

Ryan said they expect to finish design work by September of this year, and will have another meeting with residents around that time.