We’ve been wondering how long it will take to construct a permanent solution to the mangled main spillway at the Oroville reservoir. A good analog might be the 3,000 foot auxiliary spillway currently being constructed at the nearby Folsom dam. The new spillway is the massive slash from upper right to lower left:
From the Roseville Press Telegram on February 5, 2017, two days before everything went to hell at Oroville:
The $900 million structure, which runs parallel to Folsom Lake Crossing, has been in construction since [January] 2008 and is a joint project between several federal and state agencies: the U.S. Army Corps of Engineers, U.S. Bureau of Reclamation, State of California and Sacramento Area Flood Control Agency. The Corps of Engineers built the dam, while the Bureau of Reclamation excavated the spillway chute and will operate the dam when it is finished.
So assuming the all hands on deck emergency at Oroville hasn’t distracted from working on Folsom and thus the new spillway is completed on schedule this fall, construction will only have gone on for 9 years and 9 months. That schedule appears to have succeeded in keeping the cost under a billion dollars.
So, if they could get plans for a replacement spillway at Oroville drawn up this summer and start work during the dry season, they ought to get it finished by spring 2026. Hope there’s going to be a big drought until then!