wait, i can't even see an area of water near sacramento. is the delta that area of water north of concord? it would flood all the way over to sacramento??? wow.
No, the Delta is the area from (roughly) Sacramento to Tracy to Antioch.
http://www.sacdelta.com/charts/index.html
See all those islands? They are mostly surrounded by levees made up of dredged sand and silt from the channels by farmers about 100 years ago. Not engineered. Not compacted. Not a nice clay core to prevent seepage.
One strong quake in the East Bay area and bye-bye.
You thought there was a lot of flooding in New Orleans? That would be nothing. Only plus here is that these areas are sparcely populated, however if these islands flood you have all kinds of environmental and water delivery problems throughout the area and for SoCal as well. They pump water out of the south end of the Delta.....and if saltwater is intruding in the area (which it would), all those pumps shut down.