WILLIAMSTOWN, Mass. — Williams College on Monday night announced plans to install a 6 foot-by-12 foot box culvert under downtown, 

 

Williams College project manager Jason Moran explained to the Board of Selectmen that the college has put in motion a multi-phase plan that will alleviate flooding problems in and around Spring Street by, in part, replacing the undersized pipe that carries Christmas Brook under downtown and into the Green River to the east.

 

The inadequacy of the pipe that carries Christmas Brook under Williamstown has long been a vexing issue for residents in and around the Spring Street and Latham Street area.

 

"The pipe was put in at a time when people weren't quite as sophisticated about sizing the capacity of pipes," Williams College Director of Real Estate Jamie Art told the board. "When those pipes were put in, they put in the biggest pipe that would fit or whatever was lying around. We have a bottleneck somewhere on the east side of the Facilities Building, where water is forced into a 4-foot pipe, which is probably not enough for a one- or two-year storm."

 

The solution is obvious but far from easy: replace the culvert.

 

"The college has decided to bite the bullet and try to do everything it possibly can to come up with, hopefully, a permanent solution to this issue," Art said. "What the plan involves is a new culvert … that's sized properly, that's sized in connection with other stormwater infrastructure to handle a 100-year storm."

 

The culvert replacement, which goes approximately from the college's field house to a discharge point into the Green River, is part of a four-phase plan to address the entire stormwater issue at that end of town, Art and Moran explained.

 

Other aspects include restoring the Christmas Brook flood plain to the south and west, piping in Latham Street and lower Spring Street and an underwater stormwater detention system under the public parking lot that the college owns at the base of Spring Street.

 

"It's a big project, and it's going to be disruptive," Art said. "Plans are being developed to minimize disruptions, but, at the end of the day, we should have a system that will last for the rest of our lives."

 

Moran outlined some of the specifics of the plan, including what figures to be the most visible and potentially disruptive piece: the culvert replacement.

 

"It is a bottleneck at the 48-inch size pipe," he said. "At the end of the day, when trying to design for the 100-year flood event — with the actual volume given the watershed of Christmas Brook, this culvert should be 6 feet tall and 12 feet wide. That's a pretty big hole at the of the day when we start excavating.

 

"It's going to be a pretty good sized project."

 

Moran said the college planned to file paperwork with the various regulatory agencies involved — including the town's Conservation Commission on June 1 — with the hope of starting construction as soon as this fall.

 

"The culvert work is not dependent on season as much as other work because we'll be so deep in the ground that we'll be below the frost line," he said. "The goal is to complete all these projects sometime in 2019. That's a fairly aggressive construction schedule."