Pumps Provide Critical Support for Massive Tunnel Operation on D.C. Clean Rivers Project

The D.C. Clean Rivers Project in Washington, D.C., is a massive infrastructure project that will capture the combined sewer overflows (CSOs) that are wreaking havoc on the region’s waterways. The project involves the construction of four tunnels that will divert the CSOs for wastewater treatment before they reach the capital city’s rivers.

The first phase of the ambitious program was the Blue Plains Tunnel Project. A massive excavation was needed to construct the 23,600-ft. tunnel that measures 23 ft. in diameter and runs more than 100 ft. below the surface. The completed tunnel would extend from the Blue Plains Wastewater Treatment Plant past Joint Base Anacostia-Bolling to a main pumping station on the north bank of the Anacostia River, just south of Nationals Park.

Traylor Skanska Jay Dee (TSJD) was the joint venture contracting team in charge of operating a massive tunnel boring machine — dubbed “Lady Bird” by engineers — to construct the Blue Plains Tunnel. The team consisted of Traylor Brothers, an Evansville, IN-based heavy civil contractor; Skanska, a global construction group based in Stockholm, Sweden; and Jay Dee Contractors, a Livonia, MI-based firm that specializes in underground construction.

Effective Moisture Removal Throughout Excavation

As the “Lady Bird” made its way along the tunnel’s path some 100 ft. underground, pumps removed groundwater from the shaft. Concrete slurry was poured behind concrete support segments to construct the 23 ft-wide pipe through which CSOs would eventually travel.

J&K Equipment, based in Glenelg, MD, was the pump distributor responsible for supplying dewatering pumps and overseeing operations during the tunnel’s excavation. Jeff McKissack, vice president of J&K, said that he advised contractors on the job to use Tsurumi pumps based on their durability and efficiency when handling high volumes of water while enclosed in tight spaces.

“I find that Tsurumi pumps can handle higher head using less horsepower,” McKissack explained. “The process of removing excess moisture from a shaft as its excavated is a rigorous job that requires non-stop pump usage. The [15-hp] LH311W submersible dewatering pump in particular can move nearly 200 gpm at the required 160 ft. of head.

“While it’s never the intention, concrete slurry also gets removed through the pumps on a tunneling job like this,” he continued. “This typically results in the pump being scrapped fairly quickly, but we were able to wear out four sets of impellers on one of our LH311Ws before having to replace the internal seal. Since the impellers in the Tsurumi pumps are made using high-chrome cast iron, they could withstand the toll.”

The narrow dimensions of the excavation tunnel also presented a challenge on the jobsite, but the compact nature of the submersible dewatering pump helped J&K to overcome tight quarters.

“Space always matters when you’re dealing with tunneling applications,” McKissack said. “Because of [their] slimline design, the pumps don’t take up a lot of room in a sump that only measures between 10 in. and 12 in. of diameter. The 10 5/8 in.-wide LH311W was particularly handy for this project, as it was able to fit into these tight spaces and still move a significant amount of water.”

Furthering D.C.’s Cleanup Cause

The Blue Plains Tunnel Project finished construction in July of 2015, but progress toward environmental conservation in Washington continues. Excavation of the Anacostia River Tunnel Project began in June of 2013 and is expected to finish in November of 2017. When completed, the tunnel will extend from Robert F. Kennedy Stadium in Northeast D.C. to the Poplar Point pumping station in Southeast D.C. It’s expected to reduce CSOs by 98% each year for the Anacostia River alone. It is the second of four proposed tunnels that will be constructed for The D.C. Clean Rivers Project.

“Tsurumi pumps have been instrumental in our success in the first phase of the D.C. Clean Rivers Project,” McKissack said. “The efficiency, toughness and space-saving design of these pumps have helped us greatly in keeping on schedule. I have no doubts that the second phase of the project will go just as smoothly.”