Crescent/Carver Sewer Separation

"Preventing Flooding in an Urban Community"

How should an urban Massachusetts neighborhood find long-term relief from storm flooding?

MWH and S E A Consultants, Inc. have partnered together to address this concern for the Cambridge Department of Public Works. Since 1998, they've worked with city officials to design and construct facilities that provided flood relief to the Crescent/Carver neighborhood.

The team was presented an "Honor Award" by the American Academy of Environmental Engineers for the building and construction of the US $8.6 million sewer separation and stormwater management program. This award was presented at the 2002 Excellence in Environmental Engineering ceremony at the National Press Club in Washington, D.C.

25-Year, 24-Hour Protection

The Crescent/Carver program entailed building approximately 3 acre-feet of underground stormwater storage facilities within highly congested urban neighborhoods. It also included an optimized storm water conveyance system to provide 25-year, 24-hour storm protection for the entire area.

As the project was located in a busy urban environment, the program team applied unconventional construction methods to install large underground stormwater storage tanks. They maximized use of surface storage potential. This minimized the need for additional underground storage tanks. Whenever possible, the MWH team applied trenchless technologies to minimize construction disruptions while improving the infrastructure.

During the entire project, the community's comfort was a key priority.

The needs of local residents, businesses and organizations were taken into account during the project's design and construction phases. A key challenge was to gain the neighborhood's support and understanding during the heavy excavation needed to install underground storage tanks in narrow city streets. During this phase, residents awoke in the mornings to find a 90-ton excavator on their doorsteps for several weeks at a time.

An aggressive ongoing public outreach program helped inform, educate and respond to the community's needs during construction. The efforts worked to keep the community focused on the program's positive goals.

Already the new system has improved the city's stormwater management performance. During past rainstorms, there have been no reported incidents of flooding.