West Spratt Platte Soil-Bentonite Cutoff Wall & Pump Station

Project Location: Thornton, Colorado

Project Description:

Hall-Irwin was awarded this contract through a competitive bid process with the City of Thornton. Our project team was hired to construct a 311,000 SF perimeter soil-bentonite cutoff wall (also referred to as a slurry wall) around the perimeter of an existing site. This cutoff wall extended between 4 and 15 feet below the top of bedrock and up to 55 feet below the ground surface. This site posed several challenges as portions of the cutoff wall were constructed on narrow platform areas (as narrow as 18’), adjacent to roads, trails reservoirs, a river, and under high-voltage power lines.

Hall-Irwin constructed 2 underground pump stations also referred to as groundwater drain lift stations. These lift stations consisted of cast-in-place concrete wet wells and pump vaults. Each lift station contained 2 skid-mounted variable speed pumps programmed to pump based on the water levels in the wet well. Each pump is 5 horsepower and can pump up to 400 gallons per minute.

It was important to the City of Thornton that the citizens in the community were not highly inconvenienced by construction; therefore, they asked Hall-Irwin to build a multi-use trail bypass as a part of this water storage project. Our construction team constructed a new regional bike/pedtrian trail which was 10FT wide and more than a mile long to provide continuous pedestrian traffic around the area because the site required removing the existing, highly used pedestrian trail.