Over the Target: Oroville Dam -

AENN

Lake Oroville is about to rise to the top of the Ogee Weir on the Emergency Spillway at 900 feet. The date February 11, 2017 was the last time the lake level was at its current level but it quickly rose above 901 feet and “overtopped” the Ogee Weir creating a major life threatening event.

Now over 2 years later following a 2 year rebuild at an expense of over $1.2 billion to replace a destroyed main spillway and recreate an emergency spillway the risk to life and property is even greater than ever before.

Let’s be clear the purpose of the main spillway, and why it’s called the Flood Control Outlet, is to be able to release water in order to maintain storage space for anticipated future snowmelt and (rain) precipitation.

Following the re-grand opening of the main spillway on April 2, 2019 and the sudden unplanned shut down of the spillway on April 11, 2019 it was clear the spillway was severely damaged. In spite of DWR reassurances the spillway is safe and will be used again in the future the facts to date the facts defy DWR logic.

From Department of Water Resources:

April 6, 2019

Update on Oroville Operations

DWR will begin adjusting flows from the Oroville complex Sunday morning. Around 10 AM, releases from Hyatt Powerplant will decrease to zero while releases from the main spillway will gradually increase from 14,800 cubic feet per second (cfs) to 25,000 cfs. Releases to the Feather River will remain consistent at 25,000 cfs. By reducing flows from Hyatt, DWR can continue managing lake levels to provide flood protection while also observing spillway performance at higher releases. DWR will continue adjusting operations in response to updated forecasts.

In an exclusive to Agenda 21 Radio it was revealed the California State Department of Water Resources may have run an undisclosed test of the rebuilt main spillway at 60,000 csf on April 10, 2019. The Department of Water Resources gave assurances the spillway would not be opened greater that 25,000 csf but sources inside the DWR who spoke on condition of their identity would be protected said the test went to 60,000 cfs.

“the vibration was so intense, they cut it back, then off.”

Those close to the DWR commented: “that during the recent water release down the spillway, “they took it up to 60,000 cfs, but the vibration was so intense, they cut it back, then off.” “Vibration?” “Yeah, the spillway vibrates under greater releases of water.” “What causes that?”

Oroville Dam Spillway. Photo Curtis Armstrong. April 3, 2019. Copyright 2019

Facts that have developed just since the shut down of April 10, 2019 begin with massive leaks that are seen to anyone who visits the DWR live cams on top of the spillway and across the Feather River on Oro Dam Road.

Massive Leaks, Buckled Plates

The Oroville dam spillway system was suddenly and unexpectedly shut down after 12:00 pm pst Thursday April 11, 2019. The next morning there was equipment on the main spillway. At the time there was no explanation as to why the sudden complete shut down of the Hyatt power plant and the main spillway occurred or the nature as to why there appears to be equipment on the spillway deck making repairs.

According to Oroville Mercury-Register there was a planned shutdown.

From the Wednesday April 10, 2019 edition:

“OROVILLE — The state Department of Water Resources stopped releases from the Oroville Dam spillway on Wednesday because of forecasts showing upcoming dry weather.

The department said releases were halted at 1 p.m. on Wednesday. Outflows from the newly reconstructed spillway started at 8,300 cubic-feet per second, or cfs, on April 2 and peaked at 25,000 cfs on April 7.

“Releases over the past 10 days have provided adequate space in the reservoir to help provide flood protection,” said Erin Mellon, assistant director of public affairs, in a written statement. “DWR’s experts, state and federal regulators have concluded the main spillway performed as designed. Once the spillway gates close, a team of engineers will inspect and assess the spillway, and continue to monitor the instrumentation and share those updates with the regulators.”

What was not expected was the complete shut down of both the Hyatt power plant releases and the main spillway. DWR records show that both systems were stopped at 3:00 pm April 11, 2019. Later the system in the Hyatt power plant resumed.

The picture above shows the spillway partially closed but not completely sealed. DWR officials were unable to completely seal the main gates and were forced to expose workers who appeared on the spillway surface to work in several inches of water streaming in a thin sheet down the spillway.

The spillway on the right side dried enough to expose the spillway seams. As the picture above indicates there was a chalky substance that streamed down the spillway in the area where workers were seen using equipment.

After spending $1.1 billion on the Oroville Dam reconstruction, major buckling and leaking of the plates on the new spillway appeared in photos taken Tuesday, April 16, 2019.

This was the first public look at what appears to be major problems, after only a few days of the new spillway being used. According to those familiar with the situation, the plates in the spillway should be smooth, not buckling, with no leakage from between the plates, as there appears to be in these first-look photos.

An engineer inspects plates that appeared to be buckled on the Oroville Spillway April 16, 2019. The plates on the main spillway look to have buckled on the entire spillway perhaps rendering it unusable.

Picture taken April 17, 2019 shows cavitation of water on the left side of the spillway. The water is flowing down the spillway and slams into the buckled plate seams and creates a wave. The spillway is suppose to be a flat smooth surface which prevents cavitation. On the right side of the picture are leaks as water under pressure from behind the spillway forces water through the concrete.

An engineer walks the spillway inspecting buckled seams. The water are leaks from the buckled seams. To the right can be seem buckled plates against the training wall. The plate seams have lifted which is indicated by their black stripe appearance. In front of the inspector to his right at the third and fourth plate buckling of the two plates is evident.

From Department of Water Resources:

April 26, 2019

Oroville Operations and Main Spillway Update

Oroville’s current reservoir elevation is 877 feet, an increase of 10 feet from last week. Total releases to the Feather River have also increased slightly to 10,500 cubic feet per second (cfs). Oroville’s operations plan is designed to safely accommodate inflows from the above average snowpack, and DWR is aiming to keep lake levels high through spring and summer. Currently, releases from the Hyatt Powerplant are adequate to meet operational requirements of the reservoir and there is no need to use the main spillway at this time. However, we may need to use the main spillway again this year to manage inflows from increased snow melt. DWR will notify the public and media of any planned use of the main spillway.

The main spillway performed as designed when it was used April 2 through April 10, with releases topping out at 25,000 cfs. DWR engineers will continue to perform a thorough inspection of the main spillway to further evaluate its performance and will continue to be visible on the spillway structure. Water currently seen on the spillway results from normal seepage through the spillway radial gates, which are not designed to be watertight. Sandbags are used to direct the flow of water to one side of the spillway or the other to allow for safe access by DWR engineers.

Massive Leaks from Damaged Tainter Radial Arm Gates

In a release from April 26, 2019 from the DWR claimed: “Water currently seen on the spillway results from normal seepage through the spillway radial gates, which are not designed to be watertight. Sandbags are used to direct the flow of water to one side of the spillway or the other to allow for safe access by DWR engineers”.

In researching Tainter Radial Arm Gates there is NO supportive evidence that claims its “normal” for these gates to leak. In fact the day when the spillway April 2, 2019 the spillway gates were NOT leaking.

Below is the You tube from April 2, 2019 provided by the DWR which shows there were NO leaks from any of the eight Tainter Radial Arm gates.

Still images from the video prove there are is NO leakage from the gates prior to their opening. Note the deck of the spillway is smooth and even. Also the deck is wet from rain not from any leaks.

Water on the deck of the spillway is from rain not leaks from the gates.

New late spring storms are coming into Oroville and combined with a snow pack at 60% no doubt the level of the lake will rise. Remember that with the main spillway out of operation the dam must rely on either the emergency spillway or from the Hyatt Power Plant outlets which have capacity to for 13,000 cfs. At current levels of 893 feet the risk of new water coming into the lake is enormous.

In the chart from the DWR’s Lake Oroville 2018/2019
Flood Operations Plan the water level is well into the “Flood management pool” which is between 848.5ft to 900 ft. At 901 ft the lake over tops the Ogee weir of the emergency spillway which could occur in the matter of hours.

The question is what is the DWR going to do with a main spillway they cannot use and by directive in their Flood Operations Plan are directed to not use the emergency spillway? Logic would say the Hyatt Power Plant with it 13,000 cfs capability is all that’s left to use yet the DWR has lowered out flows to 4,953 cfs while inflows have jumped to over 12,304 cfs.

If they upped the Hyatt outflow, they could nearly match inflows. One has to wonder why they don’t buy more time by releasing more? Is there now a problem with Hyatt? Is it profit? Maybe they’re targeting the overtopping for a specific day. If so, I wonder why – & when.

One thing is for sure with current storms hitting the Feather River watershed the Oroville Dam is the target of choice for the next disaster.