Faced with a growing number of reasonable alternatives to the Bay Delta Conservation Plan (see below), and faced with growing evidence that recent doomsday scenarios about the vulnerability of Delta levees have been exaggerated, the Department of Water Resources and Jerry Meral have come up with a new reason to write off the Delta as we know it: the ARkStorm.
That’s AR as in Atmospheric River and k for 1000, as in a 1-in-1000 year event. Storm odds are such that we can’t write off this kind of storm happening next winter, even though we just had an Arkstorm-type flood in the winter of 1861-62. (Similarly, we can’t dismiss the possibility that a bus-sized meteor will take out Shasta Dam.) One hundred and fifty years ago, 45 days of pretty much continuous storms caused severe flooding in California, creating a lake in the Central Valley that, Meral said, “dwarfed San Francisco Bay.” It caused loss of life and millions of dollars in damage.
Meral blogged about the Arkstorm this week and then talked about it to the Delta Stewardship Council. He’s talking about “permanent inundation.” His argument seems to be that it would be impossible to strengthen Delta levees to withstand that kind of super storm, especially if we have sea level rise as well. The answer: build those tunnels under the Delta and get ready for an inland sea.
Now, you may have noticed that the 1862 storm did not result in permanent inundation of the Delta region. Eventually, the water went away. Predicted sea level rise does change the 21st century picture. But so does the fact that we have a system of dams, levees, and flood bypasses that didn’t exist in 1862. Part of that system was designed specifically to withstand a flood like the one in 1862. And we have many more people and investments to protect: a much greater incentive.
If an Arkstorm is a serious possibility, and if it were even stronger than the storm of 1862, then both BDCP and the Delta Plan are missing the boat, so to speak, with the Peripheral Tunnels. The tunnels wouldn’t be much use if the areas above the intakes and below the pumps were flooded for weeks or months.
For instance, here’s what we know about the 1862 Arkstorm:
- In the great flood of 1862, one-third of taxable property in California was lost, one-fourth of all cattle were drowned and one house in eight was destroyed (virtually all other homes were damaged).
- San Francisco received 24.36 inches of rain in January 1862 and Sonora recorded over 72 inches of rainfall between 11 November 1861 and 14 January 1862. The American River ran at more than 250,000 cubic feet per second. The bed of the Sacramento River at Sacramento was raised 7 feet by sand and mud and boats floated the streets of the city.
- The flood created a lake in the Central Valley some 300 long by 20 miles wide encompassing approximately three and a half million acres. For a week, the tides at the Golden Gate did not flood and freshwater fish were caught in San Francisco Bay for several months.
- Southern California did not escape. Great lakes formed in Orange County and the Inland Empire. The Santa Anna River ran at an estimated 314,000 cfs.
Planning for this kind of event is already happening elsewhere. In the wake of Hurricane Sandy, cities in the Northeast are beginning to look at coastal infrastructure such as sea walls. The Dutch have mobile storm-surge barriers and strategies for retaining regions below sea level for farming.
While we can and should plan and create infrastructure to protect people and property from earthquakes, floods, and sea level rise, we cannot counter every potential cataclysmic event that could take place in California. Californians being asked to invest billions of dollars in infrastructure deserve a public discussion about whether to spend it on:
- Peripheral Tunnels in a single region that will deliver over-priced water, primarily for unsustainable agriculture, and be useless in a prolonged drought, which will be even more likely with climate change, and then rendered useless when underwater during an Arkstorm:
- Infrastructure enhancements that have a reasonable chance of protecting people and property in many parts of the state from the effects of potential sea level rise, drought, and California’s inevitable floods, in addition to projects that will make each of the state’s regions as water independent as possible.