Imperial Dam Dredging and Recharge Pond Rehabilitation, Laguna Settling Basin Project Location: Yuma, AZ
Customer/Owner Name: U.S. Department of the Interior, Bureau of Reclamation
Point of Contact: Chris Patane
Description: CJW Construction, Inc. performed the maintenance dredging along the overflow weir from the headworks of the All American Canal and north along the Colorado River channel for a distance of approximately 3,000 feet, approximately 2,100 feet along the face of the dam and weir, and approximately 1,200 feet north up the secondary river channel above the Gila Sluiceway adjacent to Hidden Shores (formerly Imperial Oasis) on the Arizona side of the river channel. CJW dredged over 2,000,000 CY of sediment from the Colorado River near Yuma AZ, pumping the sand material over 14,000 feet (over 2.5 miles) to a spreading ground that CJW cleared and managed during the discharge. CJW worked closely with a manufacture in Topeka Kansas to custom design/build a new 18x16-inch Dredge and Booster that produces 3,500hp and pumps well over 12,000gpm. CJW pumped over 11,600 cubic yards per shift, with daily quantity accurately tracked via a nuclear densitometer, calibrated and confirmed by hydrographic surveys.
The subject work in the Colorado River was more challenging than in a tidal influence zone since the river fluctuates in elevation and strong flow velocity without notice. The area, Yuma Arizona, also is challenged with poor GPS satellite reception such that CJW’s Winops GPS grade control system required the purchase of a $20,000 base station upgrade to improve accuracy. The dredge was outfitted with a Doppler flow meter, electromagnetic flow meter and a nuclear density meter. CJW employed a hopper valve system from Cornerstone Industries that regulates and opens a fresh water valve under heavy load conditions to help avoid overloading the dredge pipe yet maximizing production.
For the detail work, CJW also used our state-of-the-art IMS 7012, tier 3 (CA Air Quality Requirements), 5,000 gallons per minute, 12-diameter, Hydraulic Dredge. The vessel is one of the largest one-move machines to fit onto a dropdown low-bed semi for interstate transport and it is well-suited for the detail, hard to reach areas at the Imperial Dam Dredging project. The Dredge Sand Cat is assisted by a refurbished US Coast Guard Buoy Tender the Sand Kitten plus a new service/work boat (designed to move 1,500-lb anchors) and a new 1,200 gallon Fuel Barge to fuel the dredge (4,000 gallon fuel tank).