The scenario that is most concerning is if persistent warm heavy rains come into high elevations with a deep snowpack. This is the combination that caused a 300 mile long by 20 mile wide lake in the valley to occur in 1861. It lasted for 6 months.
https://www.scientificamerican.com/article/atmospheric-rivers-california-megaflood-lessons-from-forgotten-catastrophe/
==subtitle excerpt:
A 43-day storm that began in December 1861 put central and southern California underwater for up to six months, and it could happen again
http://littlepebble.org/2017/02/18/large-usa-dam-failure-risk-emergency-evacuations/
=== excerpt:
The Central Valley of California may be facing a crisis of flooding of such massive proportions that some are concerned of the formation of an “inland lake”. In the 1860’s, this same region experienced the formation of an “inland lake” that was devastating***. It was 300 miles long and as wide as the Sierra Nevada mountain foothills to the coastal foothills. If a repeat of this massive “inland lake flood” were to occur today, millions of people will be affected. In contrast, the 1861 “Megaflood” took thousands of human lives, drowned an estimated 800,000 cattle, and bankrupted the state of California.
yes but now much of that water and runoff can be stored then released over time....
I guess the time will come, after the current situation has passed, for
“Monday morning quarter-backing” all of the decisions over the last 50 years,
but at the present time the focus is on ... “yeah, OK, so what do we do now?”
It seems like the plan is:
1- armor-up the emergency spillway as best as they possibly can;
2- drain as much water as they possibly can through the main spillway before it is no longer usable;
3- shut off the main spillway and get the hydro-electric discharge running;
4- evaluate and repair the main spillway.
What a mess.
Whoever is in the concrete business in the area is making a ton of bucks.
So much for Moonbeam Brown’s, “Oh well, stuff happens...”