Somerville, Mass., is known as the city of seven hills. Every hill has a valley, of course, and the centerpiece of one of the city’s valleys is an urban arterial called Somerville Avenue.

Somerville Avenue runs from Porter Square at the Cambridge city line through a commercial district known as Union Square, ending about a half-mile further east at Route 28 (The McGrath Highway).

Somerville Avenue has not always been a hospitable place. During rainstorms, the more than 100-year-old combined sewer system would often overflow, dumping raw sewage onto the street. Even moderate storms would flood low-lying areas, earning the area the derisive nickname “Lake Somerville.”

Gridlock awaited Boston-bound motorists attempting to drive this poorly signaled, functionally obsolete connector road from Cambridge through Somerville. Accommodations for bicyclists and pedestrians were absent, and commuters waiting for a bus had no shelter at the few stops along the route. Additionally, Americans with Disabilities Act (ADA) compliance was scant, at best.

Transforming the roadway
This all changed with the recently completed $22 million full-depth reconstruction of 1.3 miles of Somerville Avenue from Porter to Union squares. The project improved vehicular, pedestrian, and bicycle safety and efficiency; enhanced streetscape aesthetics; and updated utilities and the water/sewer system.

“Somerville Avenue was a classic example of the failure of 100-year-old infrastructure,” said David Giangrande, P.E., president of Somerville, Mass.-based Design Consultants Inc. (DCI) and engineering project manager from inception through construction. “It was an antiquated system long beyond its reasonable service life. As a result, the combined sewer system was collapsing and large sections of roadway were being swept away, creating sinkholes big enough to swallow an MBTA bus.”

Work consisted of full-depth roadway construction; sidewalk reconstruction with new granite curbing and wheelchair ramps; installation of a new drainage system; slip-lining of the existing sewer line; a new 1-1/2 mile water line; replacement of old traffic signal equipment and the addition of new signals at two warranted locations; new decorative street lighting poles and lumineres; and new trees and streetscape amenities, signage, pavement markings, and landscaping.

Additionally, private utility companies were enticed to join the effort, upgrading all gas mains and some electrical conduits to provide sufficient capacity for anticipated future needs.

Because of the project’s size, the Massachusetts Highway Department (MassHighway) was project manager. However, the project’s technical and funding complexity required the prime consultant and city staff to participate in all aspects through the construction phase.

A comprehensive approach
Originally conceived as a modest roadway reconstruction in 1997, the project’s scope expanded under the city’s current Mayor Joseph Curtatone. Recognizing the benefits of tackling the project comprehensively, Curtatone made it a priority to build consensus and encourage investment, both financial and emotional, from all stakeholders. “Most importantly, the mayor refused to take ‘no’ for an answer,” Giangrande added.

MassHighway, which has since been folded into the newly formed Massachusetts Department of Trans-portation, paid for the roadway drainage and signal improvements, while the city paid for water and sewer upgrades through the Massachusetts Water Resources Authority. A state-funded grant with a 50-percent city match covered the streetscape amenities.

“The reconstruction of Somerville Avenue is one of the most ambitious capital projects in the city’s history,” said Curtatone, who became mayor in 2004 and has overseen several major infrastructure improvement projects in the city. “It’s a vitally important project that will provide the infrastructural underpinnings to support the revitalization and growth of Union Square as an important regional commercial district.”

Somerville, the densest city by population in New England, has some experience with this type of commercial rejuvenation. Now-trendy Davis Square — one of “the hippest 15 places in America,” according to one source — was “tired, old, boarded up, and pretty seedy” in the 1970s, said one former city councilor.

Union Square never sank to those depths, nor has it rebounded to the heights of Davis Square (though its culturally diverse residents, restaurants, and shops earned it a spot among the state tourism office’s “1,000 Great Places to Visit in Massachusetts”). Yet, prior to the reconstruction project, Union Square was not only literally at a crossroads, it was facing one figuratively as well. The deficiency of the area’s public works infrastructure threatened Union Square’s viability as a commercial and residential hub.

“I’ve always said that adequate infrastructure is a basic test for any city government,” Curtatone said. “It really is a necessary foundation for any serious and effective effort to promote a livable community with sustainable economic development.”

Before reconstruction, Somerville Avenue was called “Lake Somerville” for its lack of ability to handle even moderate rainstorms.

The project took this sentiment to heart. Among the notable above-ground improvements along Somerville Avenue are a 5-foot dedicated bicycle lane with detectors at intersections; upgrades to signals at nine intersections and new signals at two additional intersections; brick paver accent strips and crosswalks with granite edging; attractive and functional bus stop shelters; and black, fluted, ornamental light poles along the entire route.

“Transportation equity was an important consideration,” said DCI’s Giangrande. “We wanted to ensure that motorists, bicyclists, pedestrians, and transit riders all gained equally.”

The end of “Lake Somerville”
The project’s most dramatic benefit, however, results from the water, sewer, and drainage improvements. Driven largely by a 1970s Environmental Protection Agency-ordered separation of the city’s combined sewer system, the changes helped resolve the city’s chronic flooding problem.

“There are two major factors,” said Massachusetts Congressman Mike Capuano, who was mayor of Somerville from 1990-1998 and helped initiate the project. “First, the street is near the end of a regional sewer system, which means that lots of water from other communities flows through Somerville on its way to the regional Deer Island treatment plant. The second factor is that the street is at the bottom of several hills covered with lots of asphalt, [concrete], and housing, which means that most rain water is directed into the sewer system, not into groundwater. These two points combine to make the project critical to flood prevention in a large, heavily populated city.”

Well-documented cases of severe flooding on Somerville Avenue underscored the adverse impact the aging infrastructure had on the local area and reinforced the need for an upgrade. In a 2005 report to the city, DCI stated: “Between 1994 and 2000, [Department of Public Works] records indicate that significant flooding occurred at least 18 times. In recent years, it has been observed that significant flooding still occurs approximately three times per year.”

In spring 2010, the Northeast suffered some of the worst rainstorms it has seen in decades. On the backs of two 50-year storms in the span of a few weeks, Massachusetts obliterated its previous March rainfall record, and a state of emergency was declared twice across the region.

Engineers installed a new storm drain along the length of Somerville Avenue, beginning as a 48-inch reinforced concrete pipe at the Cambridge line and expanding to a 66-inch pipe at Union Square to accommodate drains from side streets that empty into the system.

On newly reconstructed Somerville Avenue, however, the storms barely caused a ripple. The road that once experienced impassible flooding in even moderate storms — including dislodged manhole covers, clogged drains, sinkholes, and raw sewage overflowing into the street — experienced no extraordinary delays in the wake of the historic storms.

Following one storm, a local newspaper blog reported: “These past few days, Somerville Avenue didn’t turn into Lake Somerville. Dozens of other locations across the city didn’t flood out roadways for the first time in many, many years. That’s progress.”

Working with the city and the state, DCI’s design solution was to install a new storm drain along the length of Somerville Avenue, beginning as a 48-inch reinforced concrete pipe at the Cambridge line and expanding to a 66-inch pipe at Union Square. The increased size is to accommodate drains from side streets that empty into the system.

The project team also reinforced the existing brick-arch combined sewer main by slip lining, and added a 12-inch water main under the roadway.

These improvements do not completely separate the combined sewer system because some contributing pipelines are still combined. However, the size and composition of the new underground system will accommodate future efforts to finish the job.

“Planning for future growth was a major consideration in the design of this entire project,” Giangrande said. “A major factor in the revitalization of Davis Square was that the [MBTA] put a new Red Line station there. The Green Line is coming to Union Square in a few years, and with the investment the city and state made to reconstruct Somerville Avenue, the area is well positioned to enhance its status as a center of commerce, community, and culture.”

After more than three years of inconvenience brought on by the ambitious construction project, the residents, businesses, and commuters of Somerville Avenue and Union Square are growing accustomed to their efficient, attractive, up-to-date transportation and public works infrastructure.

“This project has already accomplished much-improved pedestrian and bicycle safety infrastructure, as well as an updated streetscape,” Curtatone said. “But the unseen aspects can mean a world of difference to a city, its economic tax base, and the quality of life for residents. Three years of infrastructure improvements and capital investments are a small price to pay for a dry basement, level roadways, and improved traffic flow for vehicles and pedestrians alike.”

Jerry Guerra is principal of The JAGG Group, a strategic consulting firm serving the AEC industry. He can be contacted at jguerra@jagg-group.com.