Pittsburgh-based geotechnical specialty contractor Nicholson Construction was recently awarded the contract for construction of a 42-inch thick, concrete diaphragm wall as part of the Louisville and Jefferson County Metropolitan Sewer District’s (MSD) Portland Combined Sewer Overflow (CSO) Basin project in Kentucky.

MSD initiated Project WIN, which includes the construction of several CSO basins, as a commitment to take the necessary measures for controlling overflows under a consent decree with the Environmental Protection Agency (EPA). A CSO basin provides temporary storage for wet weather overflows that would otherwise flow directly into nearby creeks, streams and rivers. The project’s goal is to allow for an increase in combined sewage flow to go through preliminary and primary treatment during a significant wet-weather event.

Project WIN is part of an $850 million dollar initiative that includes a series of overflow reduction projects that will be constructed over the next seven years.

The Portland CSO Basin, located on the old Portland Wharf, has a drainage area of approximately 850 acres with 61 overflows. The project is expected to reduce the number of overflow occurrences by 87% and provide for almost seven million gallons of storage.

Nicholson’s diaphragm wall will act as the support of excavation wall, and will extend approximately 46 feet to the top-of-shale for a total of more than 36,000 square feet.

 “We’re bringing many years of expertise with one of our favorite techniques to this project,” said John Wise, Senior Vice President, Nicholson Construction. “We just successfully installed a similar diaphragm wall in Omaha, Nebraska, and we’re excited about the opportunity to move our Omaha team to Louisville for another installation.”

  The General Contractor for the project is Dugan & Meyers. Construction is expected to commence in the fall of 2017.