Aug 24, 2015 by

CREDIT: Shutterstock/Dylan Petrohilos

A 2011 New York Times Magazine story sounded the alarm: “Scientists consider Sacramento — which sits at the confluence of the Sacramento and American Rivers and near the Delta — the most flood-prone city in the nation.” The article went on to note that experts fear an earthquake or violent Pacific superstorm could destroy the city’s levees and spur a megaflood that could wreak untold damage on California’s capital region.

Post-mortem studies blamed the U.S. Army Corps of Engineers and its flawed flood control system for the cataclysmic damage to New Orleans in August 2005. In 2006, the corps’ chief publicly owned responsibility, acknowledging that the levees that were supposed to prevent flooding were improperly built and relied on old data: “This is the first time that the corps has had to stand up and say: ‘We’ve had a catastrophic failure.’”

In the decade since Katrina exposed serious flaws in the nation’s levee system, much has happened. A bipartisan Congressional committee investigated and released a report. New levees were built in Louisiana. Congress voted to create a National Levee Safety Program to mitigate the threat to other high-risk areas, and state, local, and federal efforts began in earnest to prevent Sacramento from becoming the next Katrina. But despite these significant steps, the U.S. Army Corps of Engineers calls the Sacramento area “among the most at-risk regions in America for catastrophic flooding.”

In many ways, Katrina proved to be a wake-up call but much of the subsequent investment in the nation’s inadequate levee system has been driven by politics rather than science, has not received the funding required, and has been insufficiently forward-looking. And by relying on data and standards that do not reflect climate change and the rise of stronger storms that has come with it, things may be even worse than assumed.

A 64 Percent Chance

While the levee infrastructure is in grim shape in many parts of the country, multiple experts point to Sacramento and the unique geographic, seismologic, and economic factors that put it at even greater risk than the Gulf Coast.

“The levee situation was worse than New Orleans in Sacramento before Katrina. Now it’s of course worse,” said Robert Verchick, Gauthier-St. Martin Chair in Environmental Law at Loyola University New Orleans and a former EPA deputy associate administrator, who calls the aging flood-control system “a monstrous accident waiting to happen.”

“Ruptures of the levees would swamp Sacramento and places like San Francisco wouldn’t have water for weeks. That’s what keeps me up at night, thinking about those kinds of problems,” he said.

Tyler Stalker, a spokesman for the U.S. Army Corps of Engineers Sacramento District, agreed that the Sacramento area is uniquely at risk. “Two million people live here” at the “confluence of two major river systems,” he said. “Interstate 5 runs through the heart of Sacramento. Interstates 80 and 50 come right through Sacramento. These are major transportation corridors. And it’s the capital,” he added, with “a lot of water flowing through here, relying on a levee system that is quickly aging.”

To illustrate the challenge, Stalker pointed to the bathtub-like Natomas area to the north of the city of Sacramento, and the 41-mile levee system that surrounds it. “You can’t fix just one segment and expect that to work,” he explained. “If it fails anywhere, ultimately [a flood] will get in there and fill up that whole area, because of the way it’s composed.” Things need to be addressed on a system-wide basis, each is “only as good as its weakest link.”

November 2012 flood in Sacramento, CA

November 2012 flood in Sacramento, CA

CREDIT: AP Photo/Rich Pedroncelli

More than a decade ago, geologist Jeffrey Mount made a terrifying prediction: He estimated that there is a 64 percent chance of a disastrous levee failure in the Sacramento-San Joaquin River Delta (or California Delta) over the next 50 years. In an email, he told ThinkProgress that number, which “summed the risk of flood and earthquake failure” in the levee system, “was and is a conservative estimate.”

Mount, a senior fellow at the Public Policy Institute of California Water Policy Center and founding director of the Center for Watershed Sciences at the University of California, Davis, noted that there are two distinct flood risk areas: Metropolitan Sacramento, which “lies at the confluence of two flood-prone rivers, the Sacramento and the American,” and the California Delta, “the confluence of the Sacramento and San Joaquin Rivers and is the freshwater head of San Francisco Bay.”

“Rising sea level, increasing winter floods, and increasing seismic risk combine together to put this system of levees at risk of failure,” Mount warned, and “the status quo of the Delta cannot be sustained.” A 2013 study by the National Oceanic and Atmospheric Administration found that sea level rises spurred by climate change could make storm surges like those seen in Superstorm Sandy a regular occurrence.

While flooding might seem like less of a concern as California contends with its current drought, upcoming storms like the feared “Godzilla El Niño” could be even more of a threat than usual because dry ground is less able to absorb precipitation.

The Nation’s Failing Levee System

To understand the challenges in Sacramento, it helps to understand some of the history of levees and flood risk reduction. FEMA describes levees as “man-made structures, usually an earthen embankment, designed and constructed with sound engineering practices to contain, control or divert the flow of water in order to provide protection from temporary flooding.”

After the Great Mississippi Flood of 1927, Verchick explained, “Congress said it’s gonna be the job of the federal government” to protect against flooding on the “waters of the United States.” The responsibility for building federal levees was delegated to the U.S. Army Corps of Engineers, though states, localities, and private entities can also build their own levees.

Out of the roughly 14,500 miles of federal system levees, only about 2,800 miles — mostly along the Mississippi River — are owned and operated by the corps. The federal government generally pays 65 percent of the building costs and the states or localities pay the rest. After construction, Larry Larson of the Association of State Floodplain Managers notes, the corps “turns it over to a local sponsor, who is required to operate and maintain it.”

Fast forward to today and many of these and other levees are in a state of disrepair, putting millions of people and the nation’s economy at serious risk.

The corps’ National Levee Database — an inventory of all federal system levees and some state and local ones, plus the condition of each — was built thanks to the post-Katrina Water Resources Development Act of 2007. As of mid-August, it contained more than 2,500 levee systems — mostly federally constructed. Some 425 of those were found to be in unacceptable condition in their most recent routine inspections and over 1,000 more were in “minimally acceptable” condition (of the at least 47 levee systems in the database protecting Sacramento and San Joaquin County, 23 were found to be unacceptable in their last routine or periodic inspection).

Based on this data and other information, the American Society of Civil Engineers gave the nation’s levee system a grade of D-minus in its 2013 “Report Card for America’s Infrastructure.”

The Army Corps’ spokesman Stalker said that a “minimally acceptable” rating means only a minor deficiency that is unlikely to prevent a system from working in a flood and that even an “unacceptable” rating does not necessarily mean a system will fail. “Unacceptable,” he explained, means that the corps “believe it could cause an issue during a storm event,” although it is also possible “it could work just fine.” The ratings are intended help localities prioritize steps for risk reduction.

National Levee Database systems rated “unacceptable” in their most recent routine inspection

How Much Is Enough?

For a long time, Mount said, the urban Sacramento area had an inadequate levee system and was “the most at-risk” region in the country. With significant investment in infrastructure underway, he believes that “within the next ten years the area is likely to no longer be the most at-risk large city. Actually, not even close. It still will have considerable risk, but nothing like the other floodplain or coastal cities.”

Major floods in the Central Valley in 1986 “woke up the community,” said Sacramento Area Flood Control Agency (SAFCA) executive director, Richard Johnson. Another major flood in 1997, followed by the jarring images that came out of New Orleans in the wake of Katrina, were both reminders of what was at stake. “We do not want to be the next Katrina. And to the credit of the citizens of Sacramento, they’ve assessed themselves several times already and continue to give over 80 percent of the vote” to flood control assessments, Johnson said.

December 2014 flooding in Sacramento, CA

December 2014 flooding in Sacramento, CA

CREDIT: AP Photo/Rich Pedroncelli

In 2006, then-Gov. Arnold Schwarzenegger (R) proposed — and the California voters approved — a pair of water bonds that included nearly $5 billion for flood risk reduction, with a significant focus on levee repair and maintenance. “We can spend money on flood protection or we can spend money on cleanup,” he predicted. With these state funds, the California Department of Water Resources says “many of the most urgent repairs have been completed or are near completion.”

The area has also been especially fortunate to have higher-than-average federal investment in levee projects, a fact Johnson attributes to the hard work of Sacramento’s Congresswoman Doris Matsui (D). “Flood control is her number one priority. She spends a huge amount of time, effort, and resources on making sure our projects are funded,” he said, adding that a “concerted effort at all levels of government” have helped keep levee construction and maintenance moving forward.

Frank Mansell, a natural hazards program specialist at FEMA in the region that includes Sacramento, noted that both the city of Sacramento and the surrounding county are taking a lot of positive steps toward floodplain management. “They are doing the right things and exceeding the right things,” he said, noting that both have been granted significant community discounts on federal flood insurance, under FEMA’s community rating system.

But all of this investment may not be enough.

Even with the increased attention on its vulnerability, the California Delta is still at a particularly high risk, Mount, the geologist, explained. “More than 1,100 miles of aging levees of uncertain construction currently protect more than 60 ‘islands’ in the Delta,” he said. As the islands got farmed, the soils oxidized and the land elevation dropped — in many cases to 25 feet or more below sea level. “As the land lowered, the levees needed to be both wider and taller to meet the increasing hydraulic pressure. Most of these levees are privately owned and all have failed at some time in the past,” he said. While he calls the levee maintenance effort by the landowners and state “heroic,” he warns that “they are susceptible to failure from floods, extreme high tides, beavers and other rodents, and earthquakes.”

To do the necessary flood-risk reduction work for the larger region, the Army Corps’ Stalker said the corps are “proposing about $2.5 billion” worth of work. Though Congress has provided a “steady stream of funds” for the corps’ projects, with annual civil works budgets for the district between $141 million and $150 million for the past two years, he said that, even “assuming you get the funding you’re looking for, you’re looking at 20-plus years for construction, a long road.”

Nationally, levees are typically built to a “100-year flood” standard — in other words, providing protection from all but the floods that are just 1 percent likely to hit in a given year — at least, in theory. This stems from the National Flood Insurance Program, which requires those in flood paths without at least that level of protection to carry federal flood insurance. California adopted an even tougher 200-year-flood standard for levees protecting urban areas.

The issue with these estimates, however, is that they do not account for future development and climate change. In one North Carolina watershed, the increased development that came with population growth meant “flood levels went up from anywhere from two to nine feet,” Larson recalled. Every time a parking lot is built over absorbent ground, more burden falls onto the levees.

Verchick added that the 100-year flood is calculated by looking back at history and doing statistical modelling based on the question “what is the frequency with which these monster events, abnormal events will occur?” But historical records only go back so far and, with climate change, he warned, “we are looking at a no-analog future. We used to be able to look at the past and extrapolate. But now we have a future that is going to be controlled by rules of its own.”

And current information Verchick has seen suggests that in 30 years, the once-in-every-500-years flood will be a once-in-everyone-100-years flood.

FEMA is tasked with accrediting levees for the National Flood Insurance Program. The decision on whether a levee meets — or continues to meet — the 100-year-flood requirement is determined by a team of engineers like Robert Bezek. The agency’s flood mapping is based on a careful assessment of scientific data relating to rainfall, water flow, storm gauges, and comparable watersheds.

“It’s not voodoo science,” Bezek joked. But as climate change brings more severe weather, these assessments have the potential to be obsolete quickly. “We map our flood maps on current conditions. We don’t map future conditions,” he said, acknowledging that “[climate change] will have an impact; we don’t know how.”

This lack of consideration for future conditions was also evident in the post-Katrina rebuild in New Orleans.

After the levee system failure in 2005, Verchick believes the investment in New Orleans has improved flood mitigation there. “I’m not an engineer, but from talking to engineers, everything I know suggests the new levee system is a good system. There is no reason to doubt that it will provide the kind of protection that it was promised to provide.” But, even that may not be good enough. “I think there is a serious question about whether the standards that the Army Corps of Engineers was meant to follow were high enough,” he said, and the levees may be “well-built, but not protective enough.”

New levee wall in New Orleans, in 2012

New levee wall in New Orleans, in 2012

CREDIT: AP Photo/Gerald Herbert

Sandy Rosenthal, who co-founded the non-profit levees.org with her then-15-year-old son as both were evacuated from New Orleans, echoed these concerns. “In the context of haste and confusion, Congress gave more power, more authority, and $14 billion [to the Army Corps] to rebuild the system that failed. It’s like when your house falls to the ground, you say to your contractor, ‘This time, do it right! And do it really fast!’”

The rebuild still relied on unrealistic standards and lack of foresight, she explained. To provide 500-year-level protection, she said, they’d have needed to build the new levees only two to 2.5 feet higher and 1000-year-protection would have needed only one more foot beyond that. But instead, they were rebuilt to the same height and just 100-year level protection. “Politics and engineering are a lethal mix,” Rosenthal observed.

‘Fix The Roof When It’s Dry’

And while New Orleans and the Sacramento area and a few other cities have benefited from some flood prevention investments, many more are unprepared for floods or other potential disasters. “Everyone acknowledges we’ve got a levee problem and continues walking down the street,” said Gerald Galloway, a professor of engineering at the University of Maryland, College Park and a member of the American Society of Civil Engineers (ASCE). “It’s the [national] infrastructure problem, on steroids.”

Galloway noted that while teams are “working madly in Sacramento,” a better system is “not something you can put up overnight.” While “the corps and FEMA are trying to assess the challenges,” there are simply not enough budgeted funds to do so nationally.


CREDIT: Dylan Petrohilos

Other parts of the country face the challenges of extreme weather events, but many of them do not have access to the same level of funding. “Unfortunately, all of this is coming about at a time when resources at all levels of government are as strained as they have ever been,” SAFCA’s Johnson said. Few other states or localities have voted explicitly to increase their own taxes to pay for flood protections — and the Army Corps of Engineers Civil Works budget is a very limited pie.

While Washington has authorized action to address the nation’s levee system, it has not appropriated the necessary funds to make that happen. The Association of State Floodplain Managers’ Larson notes that the 2014 Water Resources Reform and Development Act created the National Levee Safety Program, but it has not yet gotten off the ground due to lack of funding: “They said we should develop standards nationally. The corps started that process, but haven’t been able to do anything with it, because Congress hasn’t funded it.”

“People say, ‘fix the roof when it’s dry,’ but we tend to fix the roof after the rainfall has gone through it,” Galloway added. “We got money for New Orleans, after the hurricane. We got money for Sandy after it occurred.” While Congress — hamstrung by spending caps and anti-tax pledges — has been unwilling to make the needed investment, the lack of investment in the needed ounces of prevention will ultimately cost the nation a lot more in pounds of cure.

“You’re gonna pay me now or you’re gonna pay me later,” Galloway said. “The bottom line is that ‘levee’ is not a four letter word. The levees on the Mississippi in 2011 did a lot for people and saved billions in damages. The 1927 flood literally crippled our nation.”

While Katrina’s death toll, the product of a delayed and insufficient evacuation effort, is not a typical characteristic of major floods, the astronomical cost associated with the resultant property damage is, Larson said. And the costs go beyond just the immediate damages, including long-term business costs, health costs, and mental health impacts. “We don’t really know how much floods cost us in the United States. We have these silly estimates that are so far off, it’s unbelievable.”

Larson noted one study found levee failure in the Sacramento area could cost ten times more than Katrina. “We need to get serious, he concluded. “We get a four-to-one return on mitigation money. But we don’t invest — we spend almost all of our money on response and immediate recovery.”

Share This

Leave a Reply

Your email address will not be published.