Over the River and Through the Levee: The York Street Pump Station and Connecticut River Crossing Project

Gus O'Leary, PE, Principal, Kleinfelder

The Springfield Water & Sewer Commission’s York Street Pump Station and Connecticut River Crossing Project is transforming the environment and ensuring a cleaner, more sustainable future for the community. Faced with an Administrative Consent Order from the U.S. Environmental Protection Agency (EPA) and the challenges of operating an aging wastewater collection system, the Springfield Water & Sewer Commission embarked on a 40-year effort to address Combined Sewer Overflow (CSO) abatement through their Integrated Wastewater Plan (IWP), one of the nation’s first approved by the EPA. The $137.6 million York Street Pump Station and Connecticut River Crossing Project is the cornerstone of the Commission’s IWP, making significant reductions in CSO frequency and volume and laying the groundwork for further reductions in the future.

To facilitate the construction of the new York Street Pump
Station, a 1,400 square foot internally braced slurry wall
system was built over the month of October 2019 (foreground).
A separate microtunnel machine launching pit was built to
facilitate the trenchless construction of the pipelines
underneath the active Amtrak Northeast Commuter Rail line and
the US Army Corps of Engineers Flood Damage Reduction System (background).

The project was also one of the first horizontal pipeline projects in Massachusetts to adopt the Construction Manager at Risk (CMAR) delivery method. This approach brought flexibility to the procurement process, enabling careful selection of scope to meet the Commission’s budgets. The involvement of the Construction Manager in discussions of contractor means and methods also played a crucial role in facilitating the project's success. Kleinfelder and Stantec together took on the responsibility of designing the improvements and supporting the Commission’s project managers, William Fuqua and Steven Frederick, and the CMAR, Daniel O’Connell’s Sons, during construction. 

Navigating site geology, environmental factors, and costs posed significant challenges for the project team. The project involved an extensive planning phase, considering 48 alternatives to achieve the objectives of the IWP. This comprehensive approach included evaluating expansion of the conveyance capacity across the Connecticut River, replacing the aging river crossing, and creating redundancy for a parallel existing system. The project scope ultimately included a new 62 MGD combined sewer pump station to replace the existing 30 MGD station; two new 42-inch force mains serving the station, each over 1,100 feet long, to replace the existing 1939 40” force main; a new 1100-ft long 72” siphon to create redundancy for the Commission’s existing 66” siphon crossing; and improvements at the Commission’s Springfield Regional Wastewater Treatment Facility to receive the additional flow. The new pump station is also resilient to a 500-year flood, providing a long-term solution to potential environmental challenges. 

An example of the benefits of the CMAR delivery method in tailoring scope to budget and mitigating risk is the use of slurry wall support of excavation for the Pump Station and tunneling excavations. This method of support of excavation is less commonly used in western Massachusetts but was successfully implemented without significant issues in both excavations. Slurry walls successfully supported both excavations for several years while minimizing groundwater management and coordination with concrete placements as construction of the pump station progressed. 

Crossing the Connecticut River was the most challenging
element of the project. A temporary trestle was built at
the Springfield Regional Wastewater Treatment Facility in
Agawam to facilitate the work (left). Steel H-piles were
installed to support the sturgeon exclusion and turbidity
barriers used to protect the endangered species (right).
The pipeline installation was completed in multiple phases
over 2 years to maintain both wildlife and vehicular passage
along this critical natural highway.

One of the project's challenges involved crossing the USACOE Flood Wall and Amtrak Rail Corridor, obstacles that required unique problem-solving. Initially, the plan was to use the jack and bore method, but unfavorable groundwater and soil conditions, coupled with the need for a receiving pit in the riverbank, posed challenges. Microtunneling not only reduced the risk of ground loss and mitigated groundwater issues, eliminating difficult and messy ground improvements near the river, but also allowed for the "daylighting" of the bores in the river, eliminating the need for a costly receiving pit. This method showcased the project team’s commitment to balancing cost with risk reduction and environmentally friendly solutions.

Another challenge was crossing the river itself. Early in design the project team vetted trenchless crossing methods. Local geology, coupled with the size of the crossing pipes, made trenchless approaches impractical leaving an open cut or dredged approach the preferred alternative. Once this approach was established, protecting both federally and state listed endangered species inhabiting this reach of the Connecticut River became the primary challenge. Controlling turbidity and excluding wildlife posed significant difficulties dredging in a riverine environment. The team utilized silt/turbidity exclusion barriers, typically employed in tidal areas, in a river setting. This unique application was critical for protecting downstream endangered mussel species and maintaining water quality standards. The barriers also served to exclude endangered species of sturgeon from the work zone, demonstrating an environmentally conscious approach.

The new 62 MGD York Street Pump Station has been built
to replace the sanitary pumping functions of the former
34 MGD York Street Pump Station. This nearly twofold
increase in pumping capacity has resulted in a reduction
of over 100 million gallons of combined sewer overflows
annually to the Connecticut River. 

Beyond its engineering feats, the project's impact extends to social, economic, and sustainability realms. The reduction of CSOs contributes to the improved health of the Connecticut River, benefiting ecosystems as far south as Long Island Sound in New York. The community's health and well-being, especially concerning recreational uses of the river, are safeguarded.

The newly constructed and operational Influent Structure
at the SRWTF was built to receive the two force mains
from the new 62 MGD York Street Pump Station as well as
the new 72-inch siphon that is a critical piece of the
next phase of the Commission’s Integrated Wastewater Plan.
Construction of this structure was complicated by the need to
maintain up to 180 MGD of incoming flows from Springfield and
neighboring communities through the use of a gravity bypass
around the project site.

Despite the complexities and challenges faced, construction commenced in June 2019 and was successfully completed in July 2023. The Connecticut River Crossing Project stands as an example of ingenuity, resilience, and environmental responsibility. The team’s willingness to consider all of the available techniques and technologies, including both microtunneling and dredging, and their commitment to sustainable solutions have set a standard for future projects. Beyond meeting regulatory requirements, this transformative project ensures the long-term health of the Connecticut River and leaves a lasting legacy of responsible engineering in the heart of Springfield.