PJ Helicopters assists in emergency repairs on Oroville Dam

PJ Helicopters’ UH-60 Utility Hawks began work on Feb. 13, 2017, after being called in to assist in stabilizing the tallest dam in the U.S. Lake Oroville, located above Oroville, California, is a reservoir capable of 77,000,000-gallon capacity, created in 1961 to store drinking and irrigation water, as well as generate hydroelectric power while flowing downward into the Feather River.

At 770 feet, the earthen dam ranks as the tallest in the country and was built with a flow capacity of 150,000 cubic feet per second (CFS).

Until recently, this CFS was sufficient but due to a wetter than average winter, the reservoir has swelled to heights not seen in decades. As a result, the dam’s primary spillway has been used heavily to accommodate the excess volume.

Last week, the high rainfall and erosion caused a 200-foot by 30-foot sinkhole to compromise the spillway, and emergency response crews have since been trying to stabilize a backup emergency spillway.

After requesting the evacuation of over 100,000 residents in Oroville and the surrounding towns, state agencies put in a request for PJ Helicopters to begin assisting on the stabilization project. Two UH-60 Utility Hawks began placing 4,500-pound crushed rock bags in high sensitivity areas to bolster the emergency spillway and add mass in the event water levels rise again.

In just under two hours, PJ crews were able to deliver more than 300,000 pounds of rock to the sites, and the current plan is to continue the efforts daily to eventually place as much as 3.3 million pounds of rock in place.

At this point in time there is potential for more of the PJH 30 rotorcraft fleet to be dispatched to the project, but no definitive plans have been made and the two Utility Hawks will continue to lead the efforts.