California May Use Partially Rebuilt Oroville Spillway

By Jonathan J. Cooper,  Associated Press

(AP) — Oroville Dam operators said Tuesday they may have to release water over a partially rebuilt spillway for the first time since repairs began on the badly damaged structure last summer.

Department of Water Resources officials said anticipated storms could trigger releases this week or next. They've stepped up releases through other outlets in hopes of avoiding the need to use the spillway.

Damage on the main spillway was the catalyst for a near catastrophe in February 2017 when authorities ordered nearly 200,000 people to evacuate amid fears of massive flooding, though the crisis was eventually averted.

Construction crews last year fully rebuilt about a third of the spillway with rebar-reinforced structural concrete that's anchored into bedrock. The other two thirds were left with temporary concrete until construction resumes, which is expected in May.

Construction work to fix the damage has paused for the winter but crews have been working in the area to fortify the adjacent emergency spillway.

State officials say inspectors will closely monitor the chute if water is released. They have said the spillway, even in its partially finished state, is capable of handling up to 100,000 cubic feet per second of water. Once finished — expected later this year or early in 2019 — it will be able to move 240,000 cubic feet per second.

Water officials last fall adopted a plan that calls for releasing water over the main spillway if the lake reaches 830 feet during April, about 36 feet above its level on Tuesday. That would ensure there's always enough room to take in more water without using the emergency spillway or releasing more than 100,000 cubic feet per second of water.

Erin Mellon, a spokeswoman for the Water Resources Department, said it's too early to know how much water might have to flow over the spillway.

"The forecasts are pretty unpredictable and dynamic right now," Mellon said.