Complex Sewer System Design for Senior Living Facility

Nestled into a plot of previously uncommercialized land near the Assabet River Rail Trail, Artisan at Hudson posed significant design challenges for the development team. Facing limitations to the existing public sewer and connection across the river, Bohler’s engineers met the sanitary system obstacles head-on, navigating around roadblocks and leveraging key relationships to bring the project to life.

Bohler provided civil engineering, permitting, and landscape architecture services for the 170-unit senior living facility. Artisan offers 61 independent living apartments, 86 assisted living units, and 23 memory care units.

Overcoming Distance to Make a Connection

With the site located more than a quarter-mile away from the closest public sewer connection point, Bohler’s team designed and permitted a private sewer line extension. Covering this distance required the engineers to navigate around other underground utilities, keeping appropriate separation between pipes, while maintaining the proper slope to allow gravity to move the wastewater.

Passing through Town-owned land, the extension also required coordination with numerous stakeholders before receiving approval.

Navigating Around Roadblocks for a Successful Upgrade

Once the facility was successfully connected, the team tackled the next challenge. The public system’s undersized pipes required an upgrade – across the river. Because it used gravity to move wastewater through the pipes, designing a system that crossed over the river wasn’t viable.

Pushing forward, the team took the design underground and decided to run the new sewer pipe beneath the river. For proper installation, piping needed to be placed at least five feet under the riverbed.

To achieve the depth required despite the river’s size and rapid flow, Bohler’s team proposed the new 12” sanitary sewer siphon be installed via directional drilling. Less invasive than trenching or cofferdams, this method uses a robotic drilling machine to bore a tunnel beneath the river, pulling the pipe through the hole to the other side.

Expediting Approvals With Local Relationships

Bohler’s collaboration with municipal stakeholders helped to design and permit the project on an expedited timeline. Since permitting a sewer pipe under a clean water source isn’t an ordinary process, Bohler’s close relationships with local reviewers allowed us to work through the design and ensure everyone was comfortable with the result. The selected pipe materials were environmentally sensitive, and Bohler specified extra layers to protect against leakage. The team successfully obtained approvals from the Conservation Commission and the United States Army Corps of Engineers (USACE), which is a complex process involving several technical reviews.

Faced with significant design challenges, this project team gave it their all. Overcoming distance, existing public system limitations, and a complicated river crossing, Bohler pressed forward, creating time-saving solutions to keep the project on track.