OROVILLE, Calif. (AP) — Water levels dropped Monday at California’s Lake Oroville, stopping water from spilling over a massive dam’s potentially hazardous emergency spillway after authorities ordered the evacuation of nearly 200,000 people from towns lying below the lake. The California Department of Water Resources said on Twitter that the spillway next to the dam was "predicted to fail within the next hour," but hours later the situation appeared less dire as the spillway remained standing. "Immediate evacuation from the low levels of Oroville and areas downstream is ordered," the Butte County sheriff said in a statement posted on social media. Nearly 200,000 people remained under evacuation orders Monday as California authorities try to fix erosion of the emergency spillway at the nation's tallest dam that could unleash uncontrolled flood waters if it fails.About 150 miles northeast of San Francisco, Lake Oroville - one of California's largest man-made lakes - had water levels so high that an emergency spillway was used Saturday for the first time in almost 50 years.The evacuation was ordered Sunday afternoon after engineers spotted a hole on the concrete lip of the secondary spillway for the 770-foot-tall Oroville Dam and told authorities that it could fail within the hour. "About 188,000 residents of Yuba, Sutter and Butte counties were ordered to evacuate.Acting Director Department of Water Resources Bill Croyle said officials will be able to assess the damage to the emergency spillway now that the lake levels have been lowered.The erosion at the head of the emergency spillway threatens to undermine the concrete weir and allow large, uncontrolled releases of water from Lake Oroville. ​Water began flowing over the emergency spillway — basically a route quickly cleared of brush to allow water to be released in a somewhat controlled fashion — for the first time in the dam's history on Saturday.
The California Department of Water Resources orders residents near Oroville Dam to evacuate, including low-lying levels of Oroville, after an emergency spillway severely eroded.