River of risk

Natomas residents are voting by mail right now on whether to assess themselves a little extra to finish bulking up 42 miles of river levees around the giant bowl they decided to live in. It’s a billion-dollar project, but for Natomans, it will work out to about $60 a year on average, or just $5 a month.

And it’s not like residents have a choice, unless they want to pay outrageously high flood-insurance rates and/or become frog people. It’s not called the Natomas basin for nothing.

Truth is, the levee project is kind of a bargain. The feds are picking up most of the tab; homeowners are just paying the local match.

But bear in mind that while the assessment will help protect people who live in Natomas now, it’s also going to open the door for more sprawl. Taking the long view, bigger levees mean more growth, and more lives and property put at risk.

“It should always be understood that it is a double-edged sword to invest in the Natomas basin,” said Ron Stork, with the environmental group Friends of the River.

Just to be clear, Stork thinks the project is the right thing to do. But investing in levee repairs means moving one giant step closer to lifting the building moratorium now in place on Natomas. (The moratorium and the new tax assessment were both the result of new studies by the Army Corps of Engineers.)

According to the Sacramento Area Flood Control Agency, if the assessment vote goes through, the building moratorium could be lifted in late 2012, early 2013.

But ultimately, it doesn’t matter how much you beef up the levees. “It’s just the geography of the place,” Stork noted. “On a typical winter, the Sacramento River is way higher than the bottom of the basin.”

That’s going to continue to be the case for a few thousand years—especially given climate change and rising sea levels. “When it comes right down to it, [Natomans] live in one of the most dangerous places in the state,” Stork said.

And when it comes right down to it, Sacramento needs to be realistic about how it calculates risk.

Right now, the probability of a flood is too high. When you build the levees up, the probability of a major catastrophe goes down. But the overall “risk” may only grow worse, because the consequences of a flood become more dire with further development. And the basin has the capacity for much, much more development.

Right now a flood would be bad, says Stork. “But it would be a lot worse with a million people living there.”

Doesn’t SAFCA take that into account? Well, yes and no. The agency does collect fees from new development to keep making flood-control improvements. Which is sort of a perverse incentive to keep building.

It would be much safer to fix the levees, then stop building new stuff in the flood plain. But that’s not too likely.

“SAFCA is not a flood-plain manager. We don’t make any land-use decisions,” said SAFCA spokesman Jay Davis. Those decisions are in the hands of Sacramento’s elected officials like the Sacramento City Council, for whom continued development in Natomas is a top priority. Stork’s advice for our city leaders? “They should take some geology and hydrology classes.”