Surveying and Imagery Support for Oroville Spillway Emergency Response

 
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In February 2017, the Oroville Dam’s main and emergency spillways were significantly damaged, resulting the evacuation of more than 180,000 people and the relocation of a fish hatchery due to the high risk of a catastrophic spillway failure. Approximately 1.7 million cubic yards of debris eroded from the side of the spillway and clogged the feather river. This raised the water levels by about 30 ft and almost flooded the upstream Hyatt Hydroelectric Power Plant. Woolpert was called in to provide critical information to assist emergency crews and engineers before, during, and after the evacuation and emergency repairs.

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Woolpert’s extensive experience in marine construction technologies and applications was invaluable to the time-sensitive requirements of onsite emergency contractors. Woolpert provided underwater imagery of the debris piles and their migration and growth towards the upstream powerplant and the diversion dam downstream of the spillway. Woolpert also collected high-resolution multibeam data to determine the safety of the turbine outlets at the power station while the structures were still submerged from the floodwaters. Woolpert set up several water level sensors to monitor the different levels of floodwaters at the bottom of the spillway to provide real-time data to DWR and the dam operators who were controlling the flow of the spillway.
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Woolpert also performed daily LiDAR surveys using a tripod mounted Reigl VZ 400, a Trimble TX8, and a Hypack NEXUS 800 aerial LiDAR drone. Woolpert collected, processed, and delivered the various data sets daily to monitor and quantify the rapidly changing topographical system. In addition, Woolpert computed volumes of erosion and deposition each day using a model that combined the various topographical datasets within the spillway area. Woolpert derived digital terrain models from the combined datasets and uploaded the models to each of the dredges that were excavating the debris from the river. All of the dredges were outfitted with dredge pack software and accompanying sensors produced by Woolpert to increase the efficiency of the debris removal process.

Location
Oroville, CA