The intersection of Boston Avenue and College Avenue in Medford has been a little busier this semester due to upgrades of water pipes beneath the roadway.
The construction is part of an ongoing effort, called the East and West Spot Pond Supply Main project, to provide clean water, according to Jonathan Yeo of the Massachusetts Water Resources Authority (MWRA).
"The water in the pipelines used to go up to the Spot Pond in Stoneham, where it would be dumped into the pond and get used later to serve the North Shore," Yeo said.
In 1997, the exposed Spot Pond reservoir was taken offlineand replaced by underground covered storage tanks, which are less susceptible to contamination.
MWRA no longer uses open-air reservoirs like ponds. "Now, the water never is exposed to the atmosphere throughout the system," Yeo said. "The water now goes through these pipelines and serves quite a few communities from Somerville and Malden and Medford, all the way out to Marblehead."
The upgrades consist of cleaning and lining the 48-inch underground pipes that are more than a century old.
Yeo said the construction crews "turn off the pipeline, reroute the water and then access the pipeline through pits every couple thousand feet," after which they can "go inside and ... scrape out the inside of the old cast iron pipe."
After it's cleaned, workers line the inside of the pipe with cement to help the hydraulic flow of the water, Yeo said.
The cement "is a good surface that doesn't allow for the iron to corrode inside of the pipe. It's better for water quality, it's better for the hydraulic flow," he said. While doing this, workers also perform general maintenance work on the system.
Work has been ongoing intermittently for most of the semester, but the current project outside Curtis Hall will be completed soon. "These projects take long periods of time to complete, because they're essentially running underground in long sections and have to be done carefully," Yeo said.
Gary Rogers, a mason working at the site, said construction was wrapping up. "Construction will hopefully be done by tomorrow or Wednesday at the latest," he said yesterday afternoon. "We're just doing some touch-ups ... we're working overtime right now. We ran into some problems this time. The cement truck didn't come in until 3:30 [p.m.], which was really late."
Water for Medford and Somerville comes from a large, newly-built, covered storage reservoir next to the Massachusetts Turnpike in Weston.
"It's a 30-foot-deep water storage tank, it covers 17 acres, it holds about 115 million gallons of water," Yeo said. "Water comes in from the reservoirs in the central part of the state, is treated and then flows through a giant new tunnel underground and pops up into that tank. Water flows by gravity from that tank all the way out into the community."
Both Somerville and Medford buy their water from MWRA, which is a wholesaler, and distribute it through their own pipelines.
