Clarence Cannon Dam Flood Repair

Work consisted of repairing damage caused by the 2008 flood event, during which water side-stepped the dam and topped the access road, destroying the road and creating a large scour in the outlet channel downstream of the dam.

The contract required RKE to complete, within a 28-day dam "shutdown" period, all phases of work that would be underwater once the gates reopened — approximately half of the project (about $3 million of work). Before construction, RKE built a cofferdam across the outlet channel, salvaged remaining aquatic life, and drained the channel via pumps. To meet the schedule, RKE ran 30 personnel 24 hours a day for 28 days straight, finishing on day 28 as the gates reopened as scheduled, then completed the remaining $3 million of work.

Major features of work: care of water; 100,000 tons of stone protection ranging from 140 lb to 5,000 lb; 60,000 SF of articulated concrete block revetment; shotcrete retaining wall; approximately 1,000' of chain-link fencing; pipe bollards; 85 tons of sheet piling; 90 LF of precast concrete toe protection anchored into bedrock with caissons; removal of channel debris; 142,000 CY of excavation; 92,000 CY of off-site disposal; geosynthetics; aggregate base course; concrete barriers; sidewalks, stairs, and handrails; turf establishment; surveying and staking; and electrical work. RKE self-performed all construction except caisson drilling and shotcrete installation.