On Tuesday, the Elementary School Building Committee heard about changes to the stormwater plan for the Charleswood School project. Members also authorized the project team to submit an expanded Environmental Notification Form (ENF) to the Massachusetts Environmental Protection Act (MEPA) office.

Submission of the form on Wednesday initiates the MEPA review of the project.

Christopher Eberly, Vertex’s senior project manager, noted the civil design originally had a small detention basin meant to clear after a 72-hour storm event. Further investigation by CMTA’s project engineer determined that expansion of the stormwater system is necessary “by a good amount.”

He showed on the plans it will go to the back side of the field that separates the two playgrounds.

Eberly relayed that from the well test pits done, on average, groundwater occurred 7 inches down on many of them, prompting the recommendation for expansion.

“In order to deal with the wealth of groundwater the town has on this site, modifications to the stormwater system are necessary,” he said.

In addition to an added structure to deal with stormwater, Eberly said there would be a “slight reconfiguration” of the chamber infiltration system.

He said what looks like plastic shells over gravel create a void where stormwater can go “and be retained while it slowly percolates into the earth or leaves the system through outlets.”

Eberly said wells would have to be relocated so as not to overlap with the detention basin.

Dan Colli, project manager at architectural firm Perkins Eastman, said the expansion of the stormwater detention area is “almost double” what was originally planned.

“There will be water left in there because the water table is very high,” Colli said.

He noted the engineers are aware of the concerns of the site’s southern neighbors regarding retention of stormwater and, “They want to make sure we have ample space.”

Well recommendation relayed

Eberly reminded the EBSC of its earlier desire to keep 10 wells beyond what was recommended to accommodate a future addition of 18 classrooms, about 1,000 square feet each for 400 students.

These future potential additions would be located at each side of the hallway, extending out of the wings on three stories.

Eberly relayed that the engineer recommended a total of 100 wells. With the 10 additional the ESBC wants, the total is the same as what the committee expressed it wanted at the last meeting.

Despite the changes, Eberly said the project remains under budget. He recommended taking the reduction of wells to lessen the monetary impact of the stormwater drainage expansion.

“Nothing makes me overly concerned that it will not fit within the budget,” Eberly said.

He noted the under-budget estimates quoted at a previous meeting would “bump back up” again because of the work. Eberly added there also are “ample contingency allowances.”

However, ESBC chair Jon Graziano said he wanted more of a concrete estimate, because he feels the changes are of a “higher magnitude” from what was previously discussed.

“I want to get a sense of what you are talking about here,” Graziano said.

Colli was instructed to reach out to the estimator for that information.

Graziano said he appreciated the work the designers had done and how they are being thoughtful about the stormwater management.

“We know it has been an issue expressed by the public as pretty significant,” Graziano said. “We want to make sure we do everything we can to mitigate and keep it as zero impact as we can. …So I think this is a good thing.”

Outreach to abutters planned

Graziano noted, with the support of Vertex, he and ESBC member Mike Shepard would be doing outreach to abutters along Hayden Rowe Street to talk about mitigation efforts that will result from the new school being there and roadwork.

“We’ll zero in on what they are thinking and see what is reasonable,” Graziano said before bringing information back to the board for its input.

Scoping session, other milestones outlined

In other business, Claire Hoogeboom of LEC Environmental Consultants spoke about the submission of the ENF to MEPA.

She said it would be published in the Environmental Monitor on May 22, and MEPA would assign an analyst. MEPA will have a “scoping session” online when members of the public and agencies can provide comments and join the meeting.

The comments will be open until June 21, with time for the project team to respond.

Other milestones include receipt of an expanded certificate followed by an outlined scope of the environmental impact report (EIR), which may involve plan modifications, she said.

The time between the certificate and submission of the EIR is unknown, Hoogeboom said. “It is difficult to determine how long it will take. It is sort of a ‘wait and see what comes up’ situation.”

Eberly noted the MEPA process is “a very long one.”

ESBC member Bill Flannery noted that a MEPA-required meeting was held in the town’s Environmental Justice Community, but no one showed up. However, he heard 17 people filled out a survey and asked if any red flags came up.

Eberly replied that comments were “overwhelmingly positive” about the project. Some comments concerned project costs and the growth in town, but those concerns “were not unique to the Environmental Justice Community,” he said, “and they mirrored the thoughts shared by a cross section of town up until now.”