Reply #8: No, this would be much, much worse than Katrina. [View All]

A catastrophic levee burst on the Delta can cause the systems inflow to cease as the rivers are redirected to flood the new area. This is bad for those being flooded, but that inflow also permits saltwater from the Suisun Bay to rush up into the normally fresh delta. The LA basin gets a very large chunk of its drinking water from the Tracy pumps, which is only a few miles up from the saltwater boundary in the bay.

In addition, there's no easy way to get that water back OUT after a flood. New Orleans has been dealing with groundwater seepage for centuries, and the city is already equipped with massive pumps that keep the water level down, and it was those pumps that cleared the water from the city after Katrina inundated it. Without the pumps the city might have stayed under water for months (you may remember the speculation about whether that might happen early on, because engineers weren't certain whether the pumps would be operable). Sacramento, like the rest of the major riverside Central Valley cities, has no similar pumping system. The vast majority of these areas have stormwater systems that drain to local evaporation ponds...which are below the levee level. In a major flood, these systems become useless.

Widespread flooding caused by a levee break could take a month or more to fully recede. When the Jones Tract flooded (a nearby island on the delta...which was flooded when a BEAVER tunneled through the levee), it took four or five months for the water to finally evaporate and saturate out, and a year until it was stable enough to be farmed again.