WorldWide Drilling Resource

26 JANUARY 2022 WorldWide Drilling Resource® Press-In Piling for Gowanus Canal Remediation Compiled by Amy White, Associate Editor, WorldWide Drilling Resource ® Constructed in the mid-1800s, the Gowanus Canal in the industrial zone of Brooklyn, New York, is considered one of the most contaminated water bodies in the United States. The canal discharges into the New York Harbor and was historically used as a prime industrial transportation route. Businesses including manufactured gas plants, paper mills, tanneries, and chemical plants have conducted operations along the canal while also emptying their wastewater into it. Along with industrial waste, overflows of untreated sewage and surface water added to the canal’s contamination over the years. Toxic contaminants including fecal coliforms and heavy metals such as mercury, lead, and copper have been found at high levels in the canal. Due to its close proximity to Manhattan and residential neighborhoods in Brooklyn, environmental cleanup of the site became increasingly necessary. In 2010, the Environmental Protection Agency (EPA) listed the canal on the National Priority List of Superfund sites, and cleanup preparations began in 2013. Work has been ongoing ever since. The project proved to be complex as workers faced issues such as minimal access to the work site. The canal is surrounded by commercial business spaces including a movie studio and special effects studio. A noisy jobsite in the middle of the city proved to be a nuisance, and early construction work on the canal also caused troublesome structural movement of existing buildings. Along with these challenges, the project had to be highly coordinated to allow marine traffic and deliveries to continue. Fortunately, these were problems that could be solved with ingenuity. The noise issue was solved with the installation of a noise dampening curtain along with a 20-foot noise barrier wall. Structural movement issues were tackled by underpinning the foundations of buildings lining the canal and developing less disturbing methods of construction work. A more recent part of the cleanup project included replacing deteriorated bulkheads facing the canal. To complete this work, a nonvibratory press-in method was used. Press-in piling proved to be a better alternative than using a vibratory hammer which had previously resulted in significant ground settlement. Press-in piling also created less noise and vibration, further aligning with requirements of the project. Bulkhead reconstruction included demolishing the old bulkhead and sections of concrete, along with taking away and disposing of contaminated soils. A large drill rig and jack-up barge was equipped for the job to perform predrilling of sheet pile alignment for removal of obstructions. Space was then backfilled with sand up to the bulkhead tip elevation. Micropiles, tiebacks, and a water system were also included in the scope of this project phase. The press-in piling method minimized settlement and displacement while reducing noise and vibrations. It also provided highly accurate installation which allowed for fully interlocked sheet pile walls verified with nondeclutching sensors. Due to the success of press-in piling on the project thus far, this method will likely be used on more segments in future phases of the project. Complete cleanup of the Gowanus Canal is estimated to cost more than one billion dollars. Excavation and restoration of the basin is expected to be finished in late 2022. Press-in piling operations along the Gowanus Canal. Courtesy of Posillico, Inc. ENV