On Wednesday, March 23, the evacuation order for Butte County was lifted after the Butte County’s Sheriff Korey Honea stated that “I feel satisfied with the progress made in reinforcing the primary spillway, emergency spillway and returning the Hyatt Powerhouse to an operational state, as well as the successful efforts by the California Department of Water Resources to lower the lake level enough to buffer for future storms.” Honea ordered the evacuation when the dam workers saw erosion in the emergency spillway, which lead to the spillway being destroyed and having to be rebuilt.

The cause of the spillways destruction was that the erosion which was grinding down not only the concrete on the surface that shaped the spillway, but also through the cracks on the surface and into the base of the spillway format. This combined with the damage already done by the erosion on the surface caused the spillway to crack open and cause large amounts of water to spill out into the surrounding rivers and flood small towns. After working for 24 hours, the workers and contractors had removed enough of the ruined dam material that allowed them to get the powerhouse back to operational level.

As of Wednesday afternoon, the amount of water that flowed out of the dam and into the lake was the same as the amount that flowed into it. This means that with the amount of work the contractors have done, the amount of water that has been allowed to flow freely that the lake has now been equaled out. In addition, the work on the dam can be increased from patching holes and filling cracks to rebuilding and improving the structure of the dam, and its spillways both emergency, which needs to be redesigned and rebuild to handle more water and fight erosion better. In addition, the main spillway that took some damage when the emergency spillway collapsed needs to be fixed and reinforced to be stronger in the case that the emergency spillway breaks again. As of four in the afternoon on Wednesday, the lake level had been changing and fluctuating around 848 feet above the sea level. According to the DWR’s website, that’s about a 9-inch decrease in 24 hours meaning the lake has settled enough for those in charge to cancel the warnings, allow the emergency services to rest, and prepare in case the dam improvement and repair takes a turn for the worse.