Tunneling Kicks Off Under Hudson Bayou



After years of confronting engineering obstacles, workers started drilling a micro-tunnel under the Hudson Bayou. The project needs to be done to connect homes on one side of the bayou with a City of Sarasota lift station being constructed in a park on US 41, and marks a step forward in the relocation of a sewage system facility in the works for more than a decade. 

While prior contractors have left the construction effort after encountering drilling problems in Hudson Bayou, the project manager for the lift station says he’s confident every precaution has been taken to avoid damage to bridges spanning the bayou or to the waterway itself. Crews on Saturday launched a micro-tunnel boring machine from a 30-foot-deep shaft south of the Osprey Bridge and will eventually connect to another shaft under new Lift Station 87. When everything is done, a 36-inch wastewater main will span under the bayou and Luke Wood Park. “In this type of operation, we are constantly watching pressure and lubrication systems—all kinds of indicators,” says Robert Garland, vice president of McKim & Creed, engineer of record for the project. “We don’t expect anything to happen, and we have measures in place in case something does happen." 

Workers will be drilling the tunnel slowly, advancing between 20 and 40 feet per day. Garland says that’s in service of carefully keeping the project on track rather than blasting through work quickly and risking environmental damage or harm to nearby infrastructure. The tunnel will be located only about eight feet below the bottom the Hudson Bayou. As the earth gets removed from the tunnel, a 60-inch diameter steel casing will be put in place in anticipation of the main being installed. “It’s a very methodical process,” he says. 

Oversight will also be constant. “We scheduled this work first to protect the City’s investment and minimize risks,” says Mitt Tidwell, Sarasota utility director. “Our microtunneling expert, Staheli Trenchless, is on site, and we look forward to completing this crucial phase of work.”

The city elected years ago to relocate a lift station in the Hudson Bayou neighborhood after high-profile spills at an aging station. City Commissioner Susan Chapman, who was involved in the early stages of that process as a neighborhood leader before being elected to the commission four years ago, says she feels optimistic about the microtunnelling work that started this Saturday. “I’m hoping it goes well,” she says. “Staheli is the national expert in microtunneling, and they are on site. That gives me confidence.” She also noted the current contractors would use much more powerful drilling machinery, something less likely to be stifled by the rocky bottom in the bayou.

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