Last fall we crossed our fingers that the predicted El Niño weather pattern would drench us just enough to alleviate California's critical drought conditions, but not so much that the flood control system would be overwhelmed (even though, as I explained here, past El Niño patterns have not been associated with big flooding events).
The critical factors for past major floods have been how early in the year water falls (earlier means reservoirs fill up and there's less room for additional rains) and whether there is significant rainfall in a short period of time.
So, did El Niño come through? Yes and no.
Yes, it came through, because we got a lot of rain and snow, at least compared to what we've received in the past four years of drought. It's been the wettest year since the drought began in 2012. Our critical Northern California reservoirs (Shasta, Folsom and Oroville) were each over 100% of historical average levels as of April 7. The State Water Project Contractors, who receive water by contract with the Department of Water Resources, are expecting to get 45 percent of requested water for 2016 (that's comparatively high based on the last few years of precipitation).
Our statewide snowpack has also fared well in the winter of 2016. As of April 1 it was 89 percent of average; skiers have rejoiced after a few dismal years.
But no, it didn't come through, because our precipitation remains below average in both Northern and Southern California, and Southern California is particularly low. Reservoirs in the San Joaquin Valley have not recovered the way northern reservoirs have.
Compared to strong El Niño patters in the past, and certainly 1997-1998, this El Niño has not impressed. Nor have we experienced major "pineapple express" storms of the kind that led to catastrophic flooding in early 1997.
Which brings us back to the first question I posed in my last blog post:
Did the 1997 floods lead to changes in the flood protection system to protect against future pineapple express storms?
Yes. After the 1997 flooding event, the Sacramento region got serious about studying and improving its levee system. That year the Governor's Flood Emergency Action Team identified a number of deficiencies in the system and priorities for investments to fix them. The team's final report made specific recommendations for (1) needed improvements in emergency response capabilities; (2) floodplain management; (3) flood control system restoration and improvement; and (4) recommendations for further studies and investigations.
It was Hurricane Katrina, though, that more urgently brought flood control to the top of the State's agenda, resulting in major bond funds for flood control improvements as well as a set of laws tying flood protection improvements to land use in the Central Valley.
One of the six strongest Atlantic hurricanes on record, Katrina caused severe destruction along the Gulf coast, most catastrophically in New Orleans where over 1,800 people were killed. Nearly 80% of the city was flooded after the levee system failed. One result of Hurricane Katrina was that the national microscope turned toward Sacramento as the next most at-risk city in the United States with respect to catastrophic flooding.
The following year California voters approved nearly $5 billion in bond funding for flood protection in the Central Valley, representing a mandate by California residents to fix the levees to prevent the kind of serious catastrophe caused on the Gulf Coast by Hurricane Katrina. Then in 2007, the Legislature passed a set of laws requiring that the State develop a flood management plan for the valley and creating a link between land use planning and flood protection. First, the law established a flood protection requirement for urban areas that is more stringent than the standard used by FEMA for flood insurance requirements. Second, the law provided that after 2017, cities and counties cannot grant development permits unless the community already enjoys that higher level of protection, or the permit is conditioned on achieving that level of protection, or the community has made adequate progress toward it.
In other words, the State wants to ensure that no new development is built behind levees until those levees are sufficient protective of urban areas. Local flood protection agencies have since been busy implementing projects to rehabilitate or improve levees, in large part with state funds.
Simultaneously the State and locals are planning for what future flooding might look like in the face of climate change.
How do you plan for a future system of facilities, the rehabilitation of which is very expensive and time-consuming, in the face of anticipated changes in precipitation patterns that we do not fully understand today? Stay tuned!
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