SITUATION: Population growth pressures forced municipal officials in Martin County to contract installation of multiple pipelines to transport wastewater to a remote treatment site. These pipelines have to cross state submerged lands, protected waterways, sensitive ecosystems as well as Eagle Nest Protection Zones. Charged with project oversight is a Who’s Who list of federal, state and local agencies. These include the U.S. Fish & Wildlife Service, Arm Corp. of Engineers, Department of State, Florida departments of transportation, environmental protection and turnpike authority; and the South Florida Water Management District. When completed, the transport system will link the county’s entire water pumping and distribution chain for the first time.

 

METRICS: The project includes multiple horizontal directional bores under the St. Lucie River at a crossing distance of about 4,280 lineal feet (about 0.8 miles). The pipelines consist of two 30-inch force mains; 24-inch reuse main and two 4-inch fiber optic conduits, plus two ancillary drills of 1400 feet each, including a 30-inch and a 16-inch water main. 

 

ENGINEER: Culpepper and Terpening, Inc.

 

CONTRACTOR: Felix Associates, LLC

 

OWNER: City of Port St. Lucie, Florida

 

CHALLENGE: The drilling project was very complex with limited space available for ECI’s large drilling equipment. It involves a close working relationship between the client, contractor, sub-contractors and engineer. ECI used boring logs and 3-D mapping software to identify a viable subsurface corridor integral to the project’s success. Due to the environmental sensitivity of the crossing area, the project had to overcome major political and geographical obstacles. Community awareness issues were also taken into account, and news fliers, public meetings, door hangers and a regular stream of press releases were an integral part of the project to keep the public informed.

 

 

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To say there was a lot riding on the success of the St. Lucie River crossing is probably best reflected in what would have happened if the project was not a success.

 

·        The sub-regional wastewater plant, already on overload, would have to be expanded in spite of strong opposition by area residents and politicians.

·        The enlarged wastewater treatment plant would have included significant expenditures for odor control, sludge treatment and enhanced landscaping to mask the facility from public view.

·        Effluent disposal using reclaimed water and deep injection would be needed.

·        Increased truck traffic through residential communities---the result of increased septage, biosolids, chemicals and other routine maintenance.

·        Additional annual operation and maintenance, plus increased manpower allocations required by state regulatory agencies.

 

ECI was contacted when the project began to encounter problems.

 

Two attempts at drilling adjacent to the initial bore hole had left sheared drilled stems and loss of back-reamers.

 

ECI was called principally because of its reputation for innovative application of 3-Dimensional existing technology and its vast experience in analyzing bore logs from original drilling operations. Other factors that prompted the contact included worldwide drill experience and some of the best equipment in the highly specialized underground boring business.

 

The upshot of that call is now in the annals of HDD (horizontal directional drilling) engineering achievement and best described in the words of a St. Lucie County environmental engineer: “The way they (ECI) had to do it, I don’t think anybody in the world could have done this, but they did. It was like threading a needle blindfolded and wearing gloves.

 

After setting up at the first of what would be multiple drill sites, ECI’s first bore dug into an opposing riverbank and started heading for a point in the north fork of the St. Lucie River, 4,280 feet to the south. It was steered by a guidance engineer relying on data from the drill bit and a sophisticated computer program.

 

That’s also when a multitude of challenges to the ECI’s drill team expertise began to surface. Some would even later characterize it as a driller’s perfect storm, and unless

handled professionally---a nightmare.

 

Local geology resulted in a road collapse that had to be repaired in order to complete drilling.

 

Drill fluid containment problems ensued.

 

Then there were several steering problems that occurred over the course of the lengthy bore. Unless corrected with the right remedy, these directional challenges had the potential to unhinge the entire project.

 

“Fortunately for us, and because of the diligence and vast experience of the field crew, we were able to overcome these obstacles and successfully complete the project,” sums up ECI President Philip Andrus. “Confronted with a situation like this where one oops leads to another, it’s nice to have some luck on your side. But the truth is, were it not for the skills and savvy of our drill team and the right equipment, any one of the challenges we encountered could have meant costly delays or perhaps even worse.” 

 

Following the project’s completion, engineers Culpepper & Turpening submitted the ECI HDD project to the Florida Institute of Consulting Engineers for its prestigious state Project of the Year Award. It won this honor, sharing it with another nominee.