Lower Santa Ana River Dredging, Orange County, CA DACW09-03-C-0018
Customer/Owner Name: US Army Corps of Engineers
Point of Contact: Joseph Ryan
Description: The Lower Santa Ana River (LSAR) Dredging Project provided final downstream improvements, maintenance and channel capacity for the large Prado and Seven Oaks Dam Flood Control project. It ultimately consisted of dredging/excavation and removal of 1,000,000 million tons of sediment from LSAR, from the Pacific Ocean to the near the 405 freeway, 4.5 miles.
Material within the tidal influence zone was hydraulically dredged utilizing a 165-ft long vessel, crane, zodiac, tug boat, separate floating hydraulic dredge, mile of cable/anchors and 20,000-ft of 12-inch diameter HDPE fusion welded discharge pipe. Sediment material unaffected by the Ocean water was dewatered, dried, gathered, screened and hauled by conventional equipment, including excavators, dozers, off-road rock trucks, loaders, Extec S5 3- Screen Plants, etc.
Operations included widespread clearing, cuts, fills, off-road-onsite and off-site truck and scraper haul of 800,000 ton of sediment material removal and transport, screening and processing of clay, silt, sand & rock products, including riprap and recycling. Millions of dollars in dump fees were diverted from local Landfills. CJW successfully constructed an asphaltic concrete bike trail via an in-house design-build, including survey and control. Work was accomplished with the most current Laser technology, utilizing grade control receivers on excavators, dozers and motor graders.
CJW completed hazardous floating dredge operations and surveys, both within the active river and open ocean without incident. The project received an overall “Outstanding” CCASS evaluation from the client.
Challenges: CJW cleared the channel blockage consisting of dense 40-ft trees, 365-foot wide by 6,000-ft long within an unstable channel bottom, ensuring that future blocks did not occur and prohibiting the willow tree debris from infiltrating the waterways of the four (4) adjacent cities. A portion of the project restored sand to the 6 acre Lease Tern Island, a preservation of natural habitat for endangered species.
All rules, regulations, SWPPP, and time restrictions were positively upheld while work was successfully completed within the largest waterway and in Southern California during the second wettest seasons ever recorded. The wet season work required close coordination with upstream water releases and dam system operators. Water flow during the dredging operation exceeded 20,000 cubic foot per second. Permits, delays and issues that otherwise would have caused cancellation of the project were resolved by partnering with the Owner and local agencies to mitigate delay and problems and potential flooding. This project would have required millions of dollars in dump fees, but CJW used new technology to separate the contaminants from beach-suitable materials, turning landfill bound materials into commodities.
Accident and Injury Free Project: Over twenty-five thousand 18-wheeler loads of material were hauled up the river and throughout City and County Streets without incident. Over ten-thousand operated hours were logged on 3 separate and simultaneously running material screening plants, without incident. CJW completed hazardous floating dredge operations and surveys, both within the active river and open ocean without incident.
LOWER SANTA ANA RIVER DREDGING, ORANGE COUNTY, CA