WILLIAMSTOWN, Mass. — The "Little Dig" is under way.

 

Williams College on Tuesday began the long process of replacing the culvert that carries Christmas Brook under downtown and into the Green River.

 

The project, part of a larger stormwater management plan that includes new underground detention tanks beneath the Spring Street municipal parking lot, is scheduled to run through May 2019 and, when it is over, greatly reduce the flooding problem that has plagued residents in that part of town.

 

On Monday, college representatives were before the Board of Selectmen to update the town on the project and seek approval of a town-gown agreement on ownership of the new culvert.

 

Like its "big" cousin to the east, the Little Dig will inconvenience motorists — though perhaps not nearly as much.

 

Unlike Boston's "Big Dig," the Williamstown project will not generate scandalous stories about the misuse of public funds. The Little Dig is being paid for by the college.

 

"The town should note that this is a project that benefits the entire watershed area while being done by a private entity," Chairman Hugh Daley said. "The cost is north of $20 million. This is a project the town of Williamstown could not afford on its own. To put it in perspective, that's a little less than our ultimate contribution to the Mount Greylock high school [addition/renovation] project.

 

"So when you're stuck in that one lane of traffic for 10 minutes, think how happy you are there's not another couple of dollars on your tax rate to deal with it."

 

Williams Project Manager Jason Moran and Director of Real Estate and Legal Affairs Jamie Art told the board that the construction plan does not anticipate any road closures during the project, which will tear up parts of Latham Street, Meacham Street, Heating Plant Drive and the old Town Garage site at 59 Water St.

 

Morgan explained that there will be times when Latham or Meacham streets are down to one lane of traffic, but they will not be closed to allow installation of 8-foot lengths of culvert measuring up to 6 feet by 12 feet.

 

"We're never going to have 400 to 500 linear feet open at once," Morgan said. "We might have 100 feet open."

 

The culvert project and parking lot project are separate but related in that they both will deal with water from the approximately 780-acre watershed that feeds into Christmas Brook.

 

"Any drop of water that falls there, if it runs off, eventually ends up draining through Christmas Brook and the undersized culvert under Latham Street and, eventually, the Green River," Art said. "[The parking lot] is where the college investigated ways to capture and retain and slow down stormwater.

 

"This project comes after a long watershed analysis looking at what are the ways the college can try to improve stormwater management in a part of town seeing increased flooding and that is forecast for wetter summers and ‘flashier' storms that are shorter in duration but more intense, leading to more flooding."

 

About 40 percent of the land in the watershed and many of the residences that experience flooding when the current culvert is overwhelmed are owned by the college.

 

"We're not exactly sure when [the culvert was installed, but it was at least 50 years ago when stormwater modeling was not as sophisticated as it is now," Art said. "The new pipe will be much larger instead of being 4 feet [in diameter] at its narrowest point as it is now."

 

The culvert project got under way in earnest on Tuesday morning with the removal of trees where water enters the current culvert, making room for a larger inlet at the site, near the entrance to Weston Field on Latham Street.

 

The parking lot work also began this spring and will be more noticeable as the months progress and portions of the existing college-owned, town-operated lot are turned over to the contractor. Moran and Art on Monday reiterated the college's intention to maximize the number of spaces available to the public during construction.

 

"We're always trying to provide a minimum of 90 [spaces] the whole time," Moran said. "If we can give you 103, we'll give you 103. If we can find a way to get six or seven more spaces above 90, we'll find a way to do it, knowing it's critical."

 

One recent change to the phasing of the parking lot project was made in response to the reaction of Spring Street merchants, who were concerned that starting work in the area closest to the commercial street during the holiday season would impact their customers. Instead, the college plans to keep the spaces closest to the street open and begin work on the west end of the parking lot first before flipping things.

 

"We would like to have the construction component of the underground detention completed by the end of May, the beginning of June," Moran said. "If it's a bad winter, we can't control it. But the idea is sometime in the summer, we'll be putting the surface back together and getting Phase 4 [the expanded municipal lot] as quickly to the town as possible. Could that reach into August? Sure. But the idea is to get 137 parking spaces back to the town as quickly as possible."

 

In addition to Monday's discussion of the project's logistics, the Board of Selectmen voted 5-0 to approve an agreement between the town and college that specifies the town will own the segments of the culvert that run under public property but that the college will be responsible for maintenance of the entire culvert.