Riverbanks collapse after #OrovilleDam spillway shut off. https://t.co/lIkgrn9uZP pic.twitter.com/MIt7Pthckk— SFChronicle (@sfchronicle) March 4, 2017
An extreme side effect of the Department of Water Resources' decision to suddenly shut off the flow of water from the Oroville Dam spillway this week in order to assess the major erosion damage there has been the loss of land along the banks of the Feather River downstream. As the Chronicle reports, farmers in Yuba City and Marysville, south of Lake Oroville, have seen almond trees, irrigation lines, and roadways all collapsing into the now lowered river because the soil was so waterlogged and the drop in the river level was so abrupt.
Almond farmer Brad Foster calls the damage "catastrophic," and Yuba County emergency operations manager Scott Bryan says he's never seen anything like this before. "The landowners understand that the water will come up and do damage to their trees," Bryan tells the Chron, "but this is different. This is actual loss of their land due to sloughing."
Most of the damage has been in Yuba and Sutter Counties, and there is potentially risk for damage of other kinds when water releases from Lake Oroville begin again, and the already collapsed sections of land begin to erode.
Water from the spillway went from flowing at 50,000 cubic feet per second to zero in a matter of hours, causing the rapid drop in the level of the river. Prune and walnut farmer Phillip Filter tells the paper that "Most of the time, they’ll give us three to five days, maybe even a week to lower the river," and this rapid change was just "ridiculous."
With the main spillway of Lake Oroville heavily damaged and causing erosion of the hillside beside the dam itself, more drama is likely to ensue as late winter and spring rains, coupled with snowmelt in the Sierra Nevada mountains, require more releases of water from the dam, but hopefully more evacuations won't be necessary like the one that was called two weeks ago, impacting 180,000 people downstream.
Meanwhile, Chinook salmon and steelhead hatchlings are requiring rescues from pools all along the Feather River that were created when the water levels dropped. The river is a main source of local salmon, and muddy, debris-filled water caused by the overflowing dam have already likely killed large numbers of the fish.
Previously: Video: New Drone Footage Shows Massive Canyon Created By Oroville Dam Spillway Erosion