Kleinfelder has been the City of Cambridge’s prime consultant for combined sewer overflow (CSO)-related sewer separation and stormwater management programs since 1998. Many of the projects are part of a Massachusetts Department of Environmental Protection (MassDEP) court-ordered program, administered through Massachusetts Water Resources Authority (MWRA) in conformance with its Long-Term Control Plan to provide a reduction in combined sewer overflows to the Charles River and Alewife Brook.
Cambridge is a densely developed community of historic structures and narrow roads. Much of its infrastructure is more than a century old. In executing the program, the City targeted adequate storm-level protection, complete sewer separation, improved aesthetics and public safety, and provision of more green space or landscaped areas. Each project area demanded different design approaches, water quality practices, and construction techniques. The City was also mindful of other water quality requirements under a separate stormwater MS4 permit and wanted to ensure that permit requirements under both permits would be advanced through this program.
Kleinfelder’s design recommendations incorporate innovative technologies, such as trenchless construction and repair, which cumulatively has saved the City millions of dollars and reduced construction-related surface impacts. Each project leverages the opportunity to enhance streetscapes through sustainable infrastructure improvements. A recent project included several low-impact techniques, such as tree planters, porous paving, low cut-off lighting, recycled materials specifications, and traffic-calming measures.
The team defined and sequenced four distinct projects, phased over a period of years, that targeted the most cost-effective program for achieving sewer separation—to improve stormwater service, minimize disruption, and promote the best solutions for retail, traffic, transit, and residential goals. To date, Kleinfelder has completed 28 projects with a construction value of more than $125 million.