Kansas Street Parallel Force Main Phase I - Lake Crossing

Pine Bluff Wastewater Utility (PBWU)’s existing force main crossing Lake Longhofer needed replacement to ensure reliable service. In partnership with Crist Engineers and Garney, PBWU and the City of Pine Bluff invested $11 million, the city’s largest infrastructure investment to date, to install 3,000 linear feet (LF) of new 42-inch parallel force main. This upgrade increases system capacity to support future growth, while the existing line remains in place to provide critical redundancy during emergencies. 

Installing the new pipeline required a subaqueous crossing and tie-ins to the existing sewer system. Garney’s marine crew used the float-and-sink method to place 1,100 LF of pipe across the lake. Cranes and barges guided the pipeline into a submerged trench, where divers completed the installation. To ensure long-term stability and prevent shifting, articulated concrete mats were placed above and below the pipe. Garney used sonar-based bathymetric survey equipment to minimize lakebed disturbance and verify pipeline alignment. 

To maintain service during construction, Garney implemented a temporary bypass system with multiple line stops, allowing flow to continue. High groundwater levels required extensive dewatering, achieved using hydraulic pumps and well-point systems to keep excavation sites safe and dry. 

With the nearest access road two miles from the work site, most materials and equipment had to be transported by barge. Pipe and marine crews worked closely to coordinate logistics, minimize delays, and keep the project on track. 

The recent upgrades represent a major investment in the future of Pine Bluff’s wastewater system. The new parallel force main provides essential redundancy and increased capacity, reducing the risk of sewer backups and overflows while reinforcing the infrastructure to support growth for the next 60 years. The recent upgrades represent a major investment in the future of Pine Bluff’s wastewater system. The new parallel force main provides essential redundancy and increased capacity, reducing the risk of sewer backups and overflows while reinforcing the infrastructure to support growth for the next 60 years. These improvements also position the system to meet the community’s evolving needs, safeguard against disruptions, and ensure sustainable, reliable service for generations to come.