Hydraulic Isolation of Lagoons or Holding Ponds
Brighton, CO: Soil-Bentonite Slurry Wall, Brannan Pit #29
Geo-Con installed a slurry wall around a sand and gravel pit adjacent to the South Platte River near Brighton, Colorado. The gravel pit will be used for municipal water storage once the mining of the property is completed. The slurry wall encircles the site and traverses the center of the property to create two separate cells.
The slurry wall is approximately 580,000 vertical square feet, with depths varying from 35 to 70 feet. The total length of wall is approximately 13,000 feet. The wall is keyed 4 feet into the Denver Blue shale formation. Geo-Con created backfill with some of the trench spoils along with overburden imported from other areas of the site. Dry bentonite was also added to the backfill to achieve permeability in the range of 1x10-8 to 1x10-9 cm/sec. This low permeability will help to meet the State of Colorado Engineer's Office requirements for leakage in this type of water storage system.