OROVILLE (CBS SF) — Butte County officials attempted to quell fears Wednesday, triggered by social media rumors, that the newly rebuilt Oroville Dam was on the brink of a catastrophic collapse.

Sheriff Kory Honea posted an open letter to Oroville residents on Twitter that proclaimed there was no “current imminent threat” of a collapse.

“I spoke to engineers and hydrology experts, I questioned them about their ability to manage the inflow,” he posted. “Based upon all that, I don’t believe there is a current imminent threat. If I come to believe there is a problem that puts the safety of our community in imminent danger I will not hesitate to alert people.”

Two years ago, about 200,000 people had to evacuate amid fears the Oroville Dam could collapse after heavy rains and mountain runoff sent a torrent of water roaring down the Feather River.

The exodus was chaotic — streets were clogged and local agencies overwhelmed. A catastrophe was normally averted.

In April, water thundered down the dam’s rebuilt spillway for the first time since 2017. Officials released 10,000 to 20,000 cubic feet of water per second to relieve pressure from the snowmelt and a rainy week of spring weather.

“We certainly have looked at the independent forensic team’s report as well as many other studies as to what caused the failure of the main spillway in 2017,” said Erin Mellon of the California Dept. of Water Resources at the time of the release. “We’ve made those adjustments and improvements based on those reports. Much of that was addressed in using 21st century design.”

A series of winter storms this year have drenched California with rain and snow that has left many of its reservoirs almost full, including the Oroville Dam, which was at 95% capacity Tuesday.

California Office of Emergency Services Director Mark Ghilarducci said state officials have been monitoring reservoir levels and releasing waters throughout the season because of this year’s high rain and snowfall totals.

The current storm “will dump some new snow in the mountains,” but is not expected to create widespread flooding because some of the snow has already melted, he said.

Comments (2)
  1. Siv Ananda says:

    ………….Much of that was addressed in using 21st century design.”

    When it comes to strength, reliability and more importantly durability of dams, I am not sure about 21st century design. Dams of yester years stood the test of times more than newer dams are likely to hold. Dam building was semi-retired since the 1970s and a lot of experiential memory was lost. The new wave of dam building internationally is fraught with inexperience of engineers being only a factor. Other factors include institutional decay such as manipulating feasibility studies to look attractive to bankers and developers and politicians. Cost cutting due to procurement methods has been a bane resulting in poor engineering, contractors cutting corners, limiting cost overruns caused by unforeseen conditions during construction as a result of having skimped on field investigations can only lead to questionable safety of dams.

    As for Oroville spillway, the independent report touches on the past shortcomings. Even the much experienced USBR was not up to par on Teton Dam while Ririe Dam only 20 miles away and with nearly the same foundation conditions as Teton was built at the same time frame by USACE and operating well. Will the future of safe dams be in good hands?