California Oroville Dam Flooding By The Numbers: How Much Will The Damage Cost And How Many People Will Be Affected?

Engineers began working on repairs Monday to the damaged concrete chute that helps to keep Northern California’s Oroville Dam from spilling over. Nearly 200,000 residents were told to evacuate amid fears of severe flooding.

Read on for a numerical breakdown of the dam, the risks and amount of water involved.

188,000 people

The number of residents urged to evacuate grew to 188,000 Monday, the Associated Press reported. Previous reports pegged the number at 100,000.

100 percent

The Oroville Dam reached 100 percent of its capacity as of Friday, up from 47 percent on that date in 2016, 45 percent the same day in 2015 and 38 percent on that day in 2014, the Los Angeles Times reported, citing the state’s Department of Water Resources.

200 feet long, 30 feet deep

The 200-foot-long, 30-foot-deep erosion hole that ripped into the main spillway alongside the dam, likely over the weekend, prompted officials to use an emergency spillway running through trees and brush. The hole in the main spillway continued to grow in the following days. (The spillway, not the dam, is the source of the risk.)

100,000 cubic feet per second

The department announced Sunday that, “to avert more erosion” of the emergency chute spilling water into a forested area, it nearly doubled the flow of the main spillway to 100,000 cubic feet per second from 55,000 cfs.

$100 million

State officials put the cost of the main spillway’s repairs at $100 million as of Friday, according to the San Francisco Chronicle. The Los Angeles Times reported a range of $100 million to $200 million.

68 inches

While Northern California normally receives 50 inches of rainfall in a given year, the region had already seen more than five and a half feet as of February, according to the Washington Post.

770 feet

The Oroville Dam is America’s tallest, beating the Hoover Dam by 44 feet, with a height of 770 feet and a crest length of 6,920 feet.

48 years

The state of California constructed the Oroville Dam nearly half a century ago, finishing it in 1968.