Oroville >> The Department of Water Resources plans to remove at least some of the debris at the bottom of the Oroville Dam spillway and study the structure, but just aren’t sure when they’ll have a chance to do that.

The workers can’t just move into the Diversion Pool and pull out the concrete, mud and other debris that went into the water after the spillway broke Feb. 7 because water is still flowing at around 60,000 cubic feet per second and they’ll need heavy equipment to get the work done.

“Crews are on the banks putting in the infrastructure so that when we decrease the flow, we can move in aggressively and possibly be in and out in a day or two,” said Chris Orrock, a spokesman for the California Department of Water Resources.

The rubble from the broken span of concrete and everything on the hillside that was not bedrock — including trees, plants, dirt and even part of an unimproved road — now lie at the bottom of the spillway and the bottom of the Diversion Pool.

Part of the debris cleanup process includes placing two excavators on barges in the Diversion Pool to dig a channel, Orrock said. Workers also have to build roads in order to get more heavy equipment in place before the department is ready to stop the flow of water.

Elevated water

In Lake Oroville, the water Tuesday was around the 852-foot elevation (the height of the water above sea level). DWR got one foot below its goal of 850 feet and acting director Bill Croyle said Tuesday in a news conference he anticipates it peak around 855 feet.

That leaves some room before water pours over the 901-foot-elevation emergency spillway again, but the lake is around 80 percent full and water continues to come into the reservoir. Plus more rain is predicted this week.

“If we continue on this wet pattern we will break the 1982 wet record for this region of the state,” Croyle said.

Still, the most recent numbers look good.

The peak flow into the lake during the latest series of storms was 106,000 cfs and the forks of the Feather River entering Lake Oroville brought around 85,000 cfs into the reservoir Tuesday. With that inflow expected to continue lessening and 60,000 cfs going down the main spillway, Croyle said the lake should be back to 850 feet Friday morning.

“We’re confident, at least based at this time, that we won’t have to use that emergency spillway,” he said.

Stopping the flow

There’s no timeline or schedule for when the flow will stop.

When the department stops running water down the spillway the geology of the rock at the bottom of the spillway has to be evaluated and the Hyatt Power Plant — at the base of the dam — will be reassessed.

The power plant is currently lower than the water level. It sits at the 232-foot elevation while the water of the Diversion Pool was around 254 feet Tuesday, Croyle said.

Water resources authorities also think they can learn more about what they’ll be able to do to fix the problem by examining the rock at the bottom of the spillway.

The focus of the department has been on responding to the broken spillway and the emergency spillway, Croyle said. After studying the area without water flowing, the department hopes to reassess the site and refine the plans for the future.

A Cal Fire representative stated Tuesday’s press conference would be the last for the spillway emergency, barring any unforeseen circumstances.