Infrastructure improvement is an unavoidable priority for the city, according to Mayor Curtatone in his presentation to the Board of Aldermen last week.

By Jordan Deschenes

Somerville’s Board of Aldermen held an official meeting on Thursday to officially discuss a variety of items, most notably a communication from Mayor Joe Curtatone regarding infrastructure redevelopment.

Mayor Curtatone’s communication pertained to the city’s outdated sewage system, the redevelopment of which he considered a responsibility to both the state and the city’s SomerVision Comprehensive Plan.

“Infrastructure … is one priority that is not optional. We can’t just kick this can down the road any longer,” said Curtatone. “I’m not gonna sugar coat this. I never have, and I’m not gonna start tonight. It will take significant investment to undergo our most significant infrastructure projects.”

To explain specific strategies required to meet such needs, Curtatone invited Richard E. Raiche, Director of the Somerville’s Engineering Department, to give a presentation.

Raiche revealed that the city’s outdated drainage pipe system is “taxed beyond capacity” during heavy rainfall, resulting in substantial flooding in downtown business districts like Union Square. Historically, most of Somerville’s drainage infrastructure was built as a one-pipe system, an antiquated practice that does not separate sewage and rainwater.

“Almost half of our system was built before 1900 and by 1940, the entire city system had been built out,” revealed Raiche. “So not surprisingly, most of our system is of the combined variety.”

Currently, around sixty percent of Somerville’s drainage flows downhill and runs eastward into a century-old line that has been regulated by the Massachusetts Water Resources Authority (MWRA) since the 1980s. This system is shared with multiple communities, including Charlestown and Cambridge.

Flooding has been exacerbated by both a lack of strategic overflow locations and a high percentage of runoff on hillsides. Recent data shows that 77 percent of Somerville’s land is impermeable to rainwater.

The city’s past efforts at addressing the flooding problem have been complicated by issues such as cost-efficiency and a lack of progressive solutions. Throughout the 20th century, nationwide floodwater management planning for cities was still based upon 19th century solutions that have now been proven to be ineffective.

By using a process known as Targeted Sewer Separation, Raiche recommended that the city build a system that would separate sewage and usable rainwater.

Raiche attributed the Engineering Department’s ability to identify specific problem areas to the rapid technological advancements in the hydraulic modeling process, many of which were not available less than ten years ago.

In identifying twelve high-risk areas around the city, Raiche and his colleagues estimated that potential damages over the next century could cost between $38.5 and $192.5 million if renovations are not made.

Somerville city officials are currently been pursuing plans to reopen the city’s pipeline capacity by redirecting rainwater into localized storm water pipes alongside existing pipes. Raiche explained that the city is hoping to link part of its waterworks with the new Green Line Extension (GLX) system in an effort to reduce reliance on that of the MWRA.

“Our biggest limitation is simply a physical one with regards to our connection to both our 100 year-old sewers, and the 150 year-old MWRA sewers,” said Raiche.

“So, when you put these things together, it’s very clear that our greatest engineering challenge lies in Union Square, which is the nexus of flows.”

For the second portion of the presentation, Robert T. King, Director of Capital Projects proposed three major infrastructure projects related to targeted sewer separation: a stormwater storage facility under Nunziato Field, a pump station at Redbridge, and sewer separation and streetscape development on Somerville Ave at Union Square.

At Nunziato Field, stored stormwater would be used for “green infrastructure” purposes, particularly for added greenery on redeveloped streetscapes in Union Square. Sewage separation at Union Square would help divert some of the volume away from the MWRA drain and into the new GLX system, with assistance from the proposed Redbridge pump station.

With the help of multiple-scenario hydraulic modeling tests, projects were ranked according to three parameters: flood reduction, cost effectiveness, and conclusions based upon consideration of all proposed projects.

Although the numbers have not officially been finalized, King estimated that costs would be around $14.6, $19.6, and $50.35 million respectively. MassWorks has agreed to cover $13 million of the $50.35 million cost as a partner for the Union Square redevelopment if a proposal is submitted before their funding deadline.

Both the Nunizato and Union Square projects are predicted to have construction timeframes of about three years.

BOA President William White Jr. reminded the board that the presentation was not an official proposal and was simply for general information purposes. He requested that the idea be submitted to the Finance Committee for consideration.

With regards to the time sensitivity of the issue, Alderman Mary Jo Rossetti questioned Director King about the transparency of the process and how to employ a more formal means of keeping residents informed about proposed developments.

Rossetti suggested that official notices for upcoming projects be sent in the mail rather than be posted as fliers, referring specifically to complaints she received from residents who did not receive information in time to submit input for past projects.

“We want to start this conversation earlier than later,” Director King replied.