WILLIAMSTOWN -- The Massachusetts Department of Transportation took a significant step last Thursday to address flooding caused by a culvert system on Route 2. In recent years, runoff from the hills to the south of The Spruces Mobile Home Park has threatened homes not only in the park, which lies in 500- and 100-year floodplains, but also those across Route 2 and as far uphill as Longview Terrace.
Eric Bollich, a Mass DOT engineer, was alerted to the issue by Mark and Chanda Shin, whose yard has flooded several times this year. Bollich toured the property and investigated the Route 2 culvert in July. The culvert was enlarged about 10 years ago, but feeds ineffectively into a smaller pipe directly after entering the Spruces property. The smaller pipe, which continues to the Hoosic River, was installed by the park's original owner in the 1960s.
Bollich ran computer models of the hydrologic activity surrounding the culvert and the nearby watershed, and presented those findings to the Conservation Commission on Thursday, Sept. 26. He was joined by Nick Hopkins and Mark Moore, also of Mass DOT, who at the same meeting presented a proposal for repaving most of the state highways in town. The culvert discussion did not involve a formal request for determination.
After receiving the Shins' complaint, Mass DOT identified streams and drainage areas uphill from the culvert. Bollich visited the site with Mrs. Shin on June 7 and further identified a 120-acre watershed near Luce Road.
Initially the computer models focused on the area directly upstream of the culvert, revealing that during 50- and 100-year storms, upstream floodwaters came about two feet out-of-bank. "So that's telling us our pipe is definitely undersized to convey water under Route 2," Bollich said. "And I think the department has acknowledged that and is willing to upgrade and install improvements there."
In another model, which included the system downstream of the culvert, upstream flooding increased from 2.2 to 2.7 feet out-of-bank. Bollich suggested that installing a new pipe underneath Route 2 might address the immediate upstream flooding, but that the smaller pipe on the Spruces property would still be a problem. He added that without control of the Spruces property, it would be difficult to make improvements.
The Spruces is currently owned by Morgan Management, which has entered into an agreement with the town to sell the park. (The town's FEMA Hazard Mitigation Grant requires that the town acquire and decommission the park, which was seriously damaged by flooding during Tropical Storm Irene in 2011.) The Spruces residents voted to waive their right of first refusal, but did so two days before receiving Morgan Management's official notice of intent to sell the park.
According to the Attorney General's Office, that made the vote invalid and the residents' best option will be to wait for the 45-day right-of-first-refusal period to expire on Oct. 5. The absence of a response from the residents will amount to a vote not to exercise their right of first refusal.
A lawyer for Morgan Management, who was present at the Sept. 26 meeting, said that Morgan Management would not be willing to pay for improvements to the park, but that if Mass DOT is "just looking for permission to come onto the land, absolutely they are going to consider that." Town Manager Peter Fohlin said the town would not acquire the park until 2016.
Bollich's conceptual plan to address the Route 2 flooding involved replacing the existing culvert with a larger, 54-inch pipe, and removing a long stretch of the older pipe on the Spruces property. In its place, Mass DOT would construct an open attenuation swale with a six-foot-wide bottom and gently sloping banks.
"I think the DOT would have no problem doing the construction, the earthwork, building it," he said. "I don't think [Morgan Management is] going to maintain it afterwards, but this does just a tremendous benefit." Based on the computer models, the stream "would not be flooding. It would be two feet below top-of-bank for the 100-year storm, 2.6 feet below for the 50-year storm."
The swale would act as a conveyance system and also as a storage area to hold the water until it has time to discharge into the river through the smaller pipe. Bollich said it would eliminate overflow on both sides of Route 2.
But there may be further obstacles. Bollich was told by an unofficial source that in the past a section of the downstream pipe experienced a failure and was replaced with a smaller 30-inch pipe. He had no documentation of that event, but ran a model for it as an added precaution. If the 30-inch pipe does exist, the swale could still store the backup water, he said, but there would need to be some extra berming "as an insurance in case the whole system collapses or fails."
At its meeting on Sept. 12 and also earlier in the summer, the Conservation Commission discussed the possibility of un-piping, or "daylighting" the entire stream between Route 2 and the river.
Commissioner Henry Art raised that possibility again at the Sept. 26 meeting. Bollich supported the idea.
"That would be beautiful because swales are always better than pipes," Bollich said. But he again pointed to the need for permission to work on the Spruces property.
Tim Kaiser, director of the Department of Public Works, pointed out that the current pipe discharges into the river through a berm, and that removing that portion of the berm may increase the likelihood of flooding from the river. There is also a 48-inch interceptor sewer coming from North Adams that crosses the culvert pipe at the river's edge. "Those issues have to get worked out," he said.
But in general, Kaiser was pleased with Mass DOT's conceptual plan for addressing the flooding. "As far as solving the issue of getting water from one side of Route 2 to the other while minimizing impact to the Spruces property, I think this is a good plan that should be developed further," he said. Kaiser will likely be involved in the project.
Bollich also investigated additional causes for the flooding, since his modeling did not account for the "flashiness and [high-flood] stages from the lower-frequency storm events." One possibility is that a drainage ditch on Luce Road connects to a lateral canal that collects runoff from a large watershed and swampy area farther east. He said the DOT has not yet investigated the area on foot. "So that's something we want to go and validate," he said.
Kaiser suggested last Monday that beaver activity near Luce Road could be redirecting more water into the Route 2 culvert. He said beavers have been observed in that area over the years, but he has not confirmed any recent activity.
Philip McKnight, chairman of the Conservation Commission, asked if the Luce Road runoff in question could be directed into the new culvert. Bollich had not considered that, but suggested that it might require a larger crossing. He did not believe the current proposal would address the uphill flooding issues. Moore said that combining the Luce Road and Route 2 drainage issues into one project would exceed Mass DOT's jurisdiction.
Moore said he would much prefer to install the new culvert prior to repaving that section of Route 2, and that Mass DOT "will have some flexibility to delay the contractor's paving of this section of Route 2 to allow time to install the pipe."
The commission unanimously approved the proposal to repave sections of Routes 2 and 7. That work will likely begin in April 2014, with completion by April 2015. Hopkins said that no roads would be shut down during that period. The project may include upgrading guardrails, sidewalk endings and curb ramps. (The new sidewalks installed near the Colonial Shopping Center this year will not be removed.)
Commissioner Sarah Gardner inquired about options for improving bikeability on the highways. Moore said that some of the road lanes will likely be narrowed from 12 to 11 feet, which would allow for easier bike travel on the road shoulders. The Planning Board has been investigating options for improved bike travel in town.
Regarding the culvert project, McKnight encouraged Mass DOT "to work with Mr. Kaiser and the other town officials to try to address this situation in the most comprehensive way possible. This is not simply a matter of getting a pipe in before it's paved over. It's trying to relieve a serious problem that's occurred for many years in the Luce Road area, and now has had an impact on the Spruces area."
Kaiser and the three Mass DOT representatives were unaware of other state-owned culverts in town in need of replacement.