Heavy storms have been taxing California's levees. Are they up to the task?
A MARTÍNEZ, HOST:
California residents are assessing the damage after a series of storms battered the state in recent weeks. The weather caused power outages, flooding and landslides and killed at least 20 people. And the rainfall also tested California's water infrastructure. In central California, multiple homes flooded over the weekend when levees were breached. We called Jay Lund, a professor of civil and environmental engineering at the University of California, Davis, to ask if the state's thousands of miles of aging levees can hold up against the pressures of climate change.
JAY LUND: These levees were built at very different times over the last more than 100 years - in some cases, about 150 years. Some of the early levees, which are still around, were made basically by farmers and landowners piling up dirt between them and the river. On some occasions, those have been formalized, and certainly for the major levees that are protecting large cities, we now have, you know, pretty well-engineered, pretty well-maintained levees that all provide finite amounts of protection.
MARTÍNEZ: And generally, Jay, when these levees were built, how long were they expected to last?
LUND: I don't think people were thinking about that so much when they were first built. You know, they were built to try to keep your property safe for the next few years, because California was growing very fast at the time. The horizons, I think, were fairly short.
MARTÍNEZ: How much is climate change affecting the situation with levees in California?
LUND: I think it's going to be increasingly important. The warmer storms can bring more moisture than they would have in the past. The floods will become bigger. We'll kind of have to adapt to that, either by increasing the channel capacities to let them pass, raising the levees to protect human structures and human people and changing the way that we operate reservoirs.
MARTÍNEZ: So it sounds like - that maybe a complete overhaul isn't necessarily required, but maybe a lot of maintenance.
LUND: That's true. We have several hundred local levee districts throughout California, certainly hundreds if not thousands of people that work on those levees all the time. I would say that we certainly have flood problems and levee problems, as you would expect with a system that has thousands of miles of levee. But I wouldn't say we're nearly starting from scratch.
MARTÍNEZ: What's the biggest, then, threat or at least maybe the biggest thing people are thinking about when it comes to - say, if we were to have this conversation 50 years from now, when it comes to California's levees, what kind of shape would we be in then?
LUND: I think we need to prepare for a future that has worse floods. Climate changes that we're seeing are pretty real. The levees function pretty well for the traditions of the past, not only in terms of climate, but also in terms of human settlement. We've been moving quite a few people into some of the flood-prone areas. And so levees that were originally built to protect agriculture now have to protect suburban areas.
MARTÍNEZ: Is California thinking enough about this?
LUND: I think we should think more about it. The hard part is to think about it consistently, even during dry periods, for years at a time, the time that it takes to plan and build flood infrastructure and the time it takes to finance and pay for flood infrastructure. People often aren't willing to pay for flood infrastructure when it's sunny out.
MARTÍNEZ: Is that something that the state of California would need to take the lead on?
LUND: Well, state of California has had several large, multibillion-dollar water bonds over the last 15, 20 years and have worked pretty well for the major urban areas. But we still have a lot of communities in rural areas that are underprotected, I think. And I think we could also do better on some of the urban areas, too.
MARTÍNEZ: That's Jay Lund, professor of civil and environmental engineering at UC Davis. Jay, thanks.
LUND: You're very welcome.
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