California's Megaflood That Could Change Everything)

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The Flood That Could Change Everything

WRITTEN BY ERIC ZERKEL

California is spending billions to protect the millions at risk of a megaflood, but thanks to climate change, it’s too little too late.

From left to right, flooding in Sacramento during the Great Flood of 1861-62, a breach on the Tyler Island levee during flooding in 1986 and floodwaters overtaking a trailer park in Manteca, California, in the 1997 floods. (California State Library, Dale Kolke/DWR, DWR)

On the first day the storm will seem just like the others. 

But once the water starts falling on Southern California this time, it won’t stop. Not for a day. Not for two days. Not even three. For 10 days the water will fall and hit the earth until the earth there can no longer contain it.

California’s first megaflood in more than a century has only just begun. 

Coastal communities in San Diego, Los Angeles and Santa Barbara will take on the Pacific as storm surge, tides and high winds push water ashore. The ocean will redraw California’s coastline as it claims chunks of beaches like keepsakes on its furthest trek inland in years. 

Cliffsides will crumble, then collapse altogether, burying coastal highways, homes and anything else that happens to get in the way of the mass of tumbling rock. 

Water has a way of exposing earth’s weaknesses, and, like a sculptor chiseling huge chunks from the earth, triggers tens of thousands of landslides, most shallow, but some deep. Each one is like a shot fired from earth’s cannon, tons of unstoppable rock and dirt returning what once was into what now is. 

In some places the water comes fast and furious, a violent inland wave taking the land by surprise. Water never settles for  long or  deeply in this part of the state though, a byproduct of the area’s often steep and narrow topography, but places like Anaheim, San Bernardino, Santa Ana, Newport Beach and Huntington Beach will suffer a different fate.

The land gets flatter where the waterways of Southern California snake through and empty into the sea. What was once Southern California’s major floodplain is now part of the state’s most urbanized area. 

More than half the population of California lives here, in the so-called South Coast hydrologic region, and within that, in the 2,800 square-mile Santa Ana watershed, large stretches of its namesake are nothing more than a concrete flume these days, nature reengineered by man in an attempt to keep what’s happened before from happening again. 

But once again, in a future reality defined by decades, not centuries, nature has exceeded the works of man. The water will burst the artificial banks of waterways like the Santa Ana and 5 to 10 feet of it will inundate the livelihoods of the millions who have changed this place over the course of decades. 

For eight more days extreme precipitation will attack California’s northern flank. From San Francisco to the boundaries of the Sierra Nevada, a new chapter of this watery disaster will begin. 

Only the topography is different here. 

Major rivers from further north in the state collide and form vast, deep floodplains that span the heart of the state. 

This is California’s most flood-prone area, but no one alive has experienced anything like this.

Water will funnel into the Sacramento and American Rivers, and where they meet, in Sacramento, the floodwaters will rise beyond control.

The state’s capital is now underwater. 

The rivers will carry the flood south, pouring it into a 40-to-50 mile wide, 400-plus mile long low-lying, flat area known as the Central Valley. When the flooding peaks, California’s inland sea will return for the first time since the 1860s and a sheen of wave-whipped water 30 miles wide and 300 miles long, 15 to 20 feet deep in places, will fill the horizon as far as the eye can see. 

All across the state nothing of man’s creation can hope to contain the great flood. Dams, reservoirs and miles of levee will be overtaken. Man’s attempt to contain nature could ultimately be the system’s downfall, and the same levees designed to hold back the water could instead prevent its escape. 

Deaths are inevitable, but unpredictable. The chances of survival are cut in half when water tops 3 feet, turning homes into coffins. In this flood, 3 feet of water is widespread. Thousands could die. 

The water will linger for days, weeks and in some places months. By the time it subsides the final toll will redefine the word catastrophe: More than $850 billion in damages (adjusted for inflation), more than four times costlier than Katrina, the costliest natural disaster in U.S. history. More than a million people forced to flee their homes in one of the largest evacuations in U.S. history, and many who return will return to nothing. 

This is California’s megaflood, a catastrophe not seen in a lifetime, but one scientists, disaster experts and officials know is coming in a warming world. No one knows when it will come, but it has happened in centuries past, and these are just some of its scientifically predicted and realistic impacts in modern day California. 

Now climate change is increasing the chances that not only will these rare flood events become the norm in California, but that in the decades to come they could be even more intense than the one predicted here.

California’s once-in-centuries catastrophe is no longer a future problem. Billions of dollars of local, state and federal action to bolster the state’s outdated flood protections have come too late and isn’t enough to protect the millions of Californians currently at risk of such an event and the millions more who will be at risk in the decades to come.

Californians are playing climate catch-up in a state that’s ground zero for climate change’s future megafloods.

What do you do if you know a disaster is coming but can’t hope to prevent it? 

California is still trying to figure out the answers, even though officials and scientists know they can’t hope to protect everyone in time.

California’s Megaflood, the ARkStorm

If this flood catastrophe was a piece of Hollywood fiction, “Megaflood” starring the Rock in bright lights would be all that’s needed to imagine the coming scenes of a disaster porn blockbuster. 

But California’s megaflood isn’t the stuff of fantasy flicks, it’s based on a 200-plus page piece of science that tested the limits of what was humanly possible in disaster prediction eight years ago known as the ARkStorm scenario.  

The ARkStorm scenario was designed with an explicit purpose in mind: to objectively quantify and qualify the California’s threat of a coming flood that only a small group of niche scientists knew the bounds of at the time.

So, when you see ARkStorm, don’t think of animals in twos, think of an equation, of X + Y = Z. Of AR (Atmospheric River) + k (1-in-1,000 chance) = ARkStorm. 

Or, more simply put, an exceptionally rare, exceptionally impactful flood. 

And about that connection to a certain famous ark?

“The double entendre of the name seemed appropriate for a flooding scenario of potentially catastrophic proportions,” said Dr. Marty Ralph. 

Ralph was one of the scientists who, along with a group of 116 others, drafted the so-called ARkStorm scenario. So seminal is his work that he’s considered among his peers as one of the “godfathers” of atmospheric river research. 

And atmospheric rivers (ARs) are the protagonist for this tale. 

An AR isn’t really a singular storm per se, it’s more like opening a narrow, long superhighway from the atmosphere to an indiscriminate point on the map on which extreme amounts of water travel. 

Most of that is carried in the form of water vapor, but there’s so much water — on average 25 Mississippi Rivers’ worth in each AR — that when a storm system taps into one and makes landfall under the right conditions, the results can be devastating. 

From October to March that highway of moisture often gets routed toward the West Coast of the United States, particularly California. Most atmospheric rivers aren’t extreme, or even strong for that matter, but when they are they’re the single greatest weather threat in the state of California. 

Researchers found that just a handful of the wettest days in a year were responsible for 85 percent of all changes to the year-to-year precipitation totals in Northern California.

Ultimately, just five to 15 days with or without ARs a year decide whether California floods or descends into drought.

“By the far the most variable annual hydroclimate is in California and the southwestern part of the country. One of the reasons for that is we’re in a subtropical climate, a mediterranean climate, and these ARs produce big fractions of the annual precipitation,” Ralph said. 

“It turns out we’ve connected ARs to 80-plus, even 90-plus percent of significant flooding events in the West Coastal states. So if we get fewer ARs we don’t get enough rain annually. If we get too many we end up in flood.”

Marty Ralph on a tour of an Air Force “Hurricane Hunter” C-130 earlier this year. Ralph and a crew plan to fly the planes into atmospheric rivers again this winter to acquire more data to improve forecasting of the phenomenon. (Erik Jepsen / UC San Diego Publications)

None of this atmospheric river knowledge even existed two decades ago. Statistics like how much water the average atmospheric river transports — that 25 Mississippi Rivers-worth number — were discovered only in the last couple of years.  

So forecasting atmospheric rivers, predicting exactly where they’ll landfall and how much flood-inducing water they could dump on the state, is still a murky science at best. 

In 2013, researchers discovered that AR landfall forecasts five days out have margin of error of 500 km (310 miles). That’s like saying on Sunday that an atmospheric river could hit somewhere between the Los Angeles Metro or the San Francisco Metro on Friday.

Two days before landfall that margin of error improves to 250 km (155 miles), but the forecast error still lags behind other notorious weather systems, like hurricanes. 

“The ballpark, round number would be that the AR landfall position error at two days is about twice that of the hurricane track error,” said Ralph. 

Predicting exactly how devastating an AR could be is still a struggle, too. In 2010, Ralph’s research revealed that the average AR forecast underestimated the amount of precipitation in these events by up to 50 percent. 

Ralph believes that precipitation forecasts likely have improved since 2010, but said more research needs to be done to quantitatively prove that. 

As for improving landfall predictions? 

“Get back to me in a year or two and we should have some sense of where the trends are in terms of the skill of predicting landfall,” said Ralph.

So much can change in the world of atmospheric rivers in just “a year or two.”

In 1998, no one even knew what an atmospheric river was. Back then they were just West Coast winter storms, devastating flood producers that happened between October and March.  

At the time, Ralph was flying into storms off the coast of California in a NOAA P-3 aircraft, dropping data-collecting tools called dropsondes into the storms over the Eastern Pacific, like some sort of hurricane hunter of the West. 

Ralph was flying into atmospheric rivers. He just didn’t know it yet. 

It took a 1998 paper by Yong Zhu and Reginald E. Newell, the first to outline the specific components of an AR, the dropsonde data that Ralph acquired through his flights into the storms, and a new NASA satellite dubbed SSM/I that allowed scientists to track water vapor in the atmosphere, even with clouds present, for Ralph to realize what he was really studying. 

“You could almost put a plus sign between those and then an equals lightbulb. And that’s exactly how it happened,” said Ralph. “I realized, that’s what we were flying through and studying.”

For Ralph and AR scientists alike, it was all a godsend, a flick of the mental light switch that allowed them to frame their research efforts with this now tangibly defined thing known as an atmospheric river. 

But they needed more data to help predict ARs and understand the hows and whys of their role in California’s water cycle, so Ralph got to work. 

A first of its kind experiment known as CalJet led to more flights into storms through 2003. In 2008, Ralph helped form and lead an initiative called CalWater to develop more advanced measurements by land, sea and air. CalWater-2 followed that in 2014 and beyond with more observations. 

Ralph, now the director of the Center For Western Weather and Water Extremes at University of California San Diego, plans to collect more data this winter, but more than a decade of data acquisition and the ensuing research on atmospheric rivers has yielded dividends.  

The data allowed scientists to see, for the first time, the sort of minutiae that can make or break an atmospheric river forecast.

Through observations gathered through the CalWater project in 2009, researchers found that dust from Asia, transported through the atmosphere, likely helped increase precipitation in an AR in California by 40 percent. 

Before that, there was no physical proof that aerosols — like dust — could influence the forecast of an AR, but now that knowledge could improve forecasts in the future. 

And yet, despite all of this work, if you haven’t heard of an AR until now, you’d be among the majority. 

Only in the past year did an official definition of an atmospheric river make it into the glossary of meteorology, the American Meteorological Society’s document of all things weather and climate. 

It’s a moment that Ralph is proud of, a cherry on top for AR scientists who’ve been working for years on furthering the understanding of this threat. 

Now they’re watching as this “mature science” on the West Coast of the U.S. starts to spread into the public consciousness, something that was unimaginable 20 years ago. 

Ralph recalls a colleague’s story about an NFL commentator using the term to describe the weather while calling a game in the San Francisco Bay area a couple of years ago.

“The announcers were pointing out how heavy it was raining and one of them said, ‘Oh, that must be an atmospheric river,’” Ralph said. “That’s an example of this jargon penetrating to the population.”

Slowly, but surely, Ralph says, the public in affected places is learning the cause for all of these disastrous floods: atmospheric rivers.

“It’s an emerging awareness in the West that this is an important phenomena and there’s information out there about them and it’s only going to continue to grow in terms of public utility and awareness,” said Ralph.

“They are the hurricane problem of the west, except they’re not a hurricane, they’re an AR. But societally, they are the phenomenon in the weather that produces big impacts.”

This January 1862 photo shows floodwaters along K Street looking west from 4th street in Sacramento after the Great Flood of 1861-62. (California State Library, DWR)

The Great Flood and the Greater Floods

“Nearly every house and farm over this immense region is gone. There was such a body of water — 250 to 300 miles long and 20 to 60 miles wide, the water ice cold and muddy — that the winds made high waves which beat the farm homes in pieces. America has never before seen such desolation by flood as this has been, and seldom has the Old World seen the like. But the spirits of the people are rising, and it will make them more careful in the future. The experience was needed. Had this flood been delayed for ten years the disaster would have been more than doubled.”
– William H. Brewer, February 9, 1862, San Francisco — The Journal of William H. Brewer 

For more than 40 days in 1861-62 the rain and snow fell on California, forming California’s 300-mile-long, 20-mile-wide so-called inland sea, flooding Sacramento in feet of water, killing thousands of people and 800,000 livestock. 

So deep and widespread were the floodwaters in Sacramento, that the state’s capital had to be temporarily relocated to San Francisco to keep the government operational. 

California’s so-called Great Flood of 1861-62 is the worst in state history and the state’s first memory of a flood even worse than the ARkStorm. 

But California’s memory of flooding is generational, so very few know of the most intense floods in the region. The floods that happened before California was California. 

These floods predate those in 1861-62, some having occurred before the written history of man, but proof of them lies in the seafloor off the coast of southern California, in the Klamath Mountains and in a small lake called Little Packer. 

Undisturbed layers of sediment deposited in those places by bloated waterways are the only reminders in the geologic record of megafloods past.

Analysis of the sediment, detailed in brief in Scientific American by another one of the scientists on the ARkStorm project, Michael Dettinger, shows that megafloods have a detailed history of occurring every 200-or-so years and that some of those floods were clearly more severe than the one in 1861-62.

“The unsettling bottom line is that megafloods as large or larger than the 1861-62 flood are a normal occurrence every two centuries or so. It has now been 150 years since that calamity, so it appears that California may be due for another episode soon,” the authors write.

And there have been recent reminders of one, as recently as this past wet year in California. 

At least 45 atmospheric rivers hit the state from October 2016 through March 2017, 15 of which were considered strong or extreme.

Those ARs produced the second-most water runoff in state history, eviscerating California’s worst drought in 200 years, but produced a flood disaster.

By the time the drought was gone, floods had caused an estimated $1.5 billion in damage. There were deaths and mass evacuations. Levees failed and a spillway at a major dam’s reservoir was damaged.

Yet, according to the California Department of Water Resources, had the timing of individual storms played out differently, more like the ARkStorm scenario, major flooding would’ve taken place on the state’s largest rivers and the flood disaster would’ve been much worse. 

Despite the destruction, last year’s wet season was a comparative miss, a first major reminder in two decades of what atmospheric rivers were capable of, and maybe, the first example of flood disasters to come.

A woman uses a kayak to check her flooded home on Jan. 11 2017, in Guerneville, California. (Santiago Mejia/San Francisco Chronicle/via AP)

A Changing Climate, a Growing Risk

Dr. Ashley Payne’s first big conference as a grad student studying atmospheric rivers in 2013 didn’t go quite as she’d imagined.

“I went there and said ‘I’m looking at atmospheric rivers’ and there were so many people who came up to me and said ‘that’s not real,’” Payne said. 

Specifically, Payne said, there was still confusion in the atmospheric science community about what an atmospheric river was, before that whole official definition business. 

Now, Payne said, there’s a growing scientific interest and understanding of atmospheric rivers, particularly around improving forecasts by studying recurring climatological and atmospheric features — things with names that you might’ve heard of like El Nino and others with names you probably haven’t, like Rossby waves. 

And that’s important, because the more scientists learn about the complicated, interconnected world of the atmosphere the more they can figure out how the recurring patterns and features of it influence the intensity and frequency of atmospheric rivers on a forecastable scale.

“Being able to forecast the intensity and impact (of an AR) at a sub-seasonal scale — so like two weeks out, maybe 10 days out — comes with looking at these climate patterns that fluctuate on a much higher frequency,” said Payne “You have to think about how everything fits together. It’s a complicated puzzle, that’s why there’s still ongoing research. If we can link AR behavior to the MJO (a recurring disturbance in the atmosphere in the tropics) then we’re more able to tell Joe Schmoe on the coast of California that there’s about to be a bad atmospheric river based on that.”

That’s where Payne comes in, she’s one of the lot trying to identify pieces to that atmospheric puzzle.

Changing Climate, Changing Floods

Climate change's expected increase in temperatures and extreme precipitation will combine to produce more epic floods in California. This graphic shows how warmer temperatures will melt snowpack quicker and dump more rain and less snow on mountain ranges, leading to more prolific floods. Source: California Department of Water Resources 2017

Payne’s work at the University of Michigan, where she’s a research fellow, is focused on the evaluation of weather extremes in climate models, but her past work has shown how changes and features in the atmosphere — particularly those Rossby waves — can influence the behavior of ARs.

Payne’s research found that when Rossby waves — think of waves in the atmosphere that break in predictable places, just like waves in the ocean when they get close to shore — break in a particular direction they tend to produce more intense atmospheric rivers. 

All of the locations where Rossby waves break in the atmosphere already have been identified by scientists and one of them is right off the coast of California.

“It’s easier to predict Rossby waves than atmospheric rivers, so if we can relate atmospheric rivers to Rossby waves breaking then that would be a step forward in the right direction,” said Payne. 

There’s still much to learn to complete our understanding of atmospheric rivers’ role in our atmosphere. 

Yet, there seems to be some relative consensus on one AR topic: “Future atmospheric rivers are going to be more intense. That’s something I would say is a pretty robust result across a number of studies,” Payne said.

The reason? Global temperatures are on the rise due to climate change, and there’s a well established physical law, known as the Clausius-Clapeyron equation, that shows that for every 1-degree change in temperature there’s a 7 percent increase in the atmosphere’s ability to store water.

Dr. Ashley Payne’s work at the University of Michigan, where she’s a research fellow, is focused on the evaluation of weather extremes in climate models. (Ashley Payne)

More water in the atmosphere means more water available for atmospheric rivers to pump into places like California. 

“(Future ARs will) likely (be) more frequent, with some being stronger than we are used to because they may carry more water vapor,” ARkStorm drafter Marty Ralph said in an email.

Further consensus on the future of ARs is found in the federal climate assessment report, a comprehensive assessment of specific climate change risks to the country. 

“The frequency and severity of landfalling ‘atmospheric rivers’ on the U.S. West Coast … will increase as a result of increasing evaporation and resulting higher atmospheric water vapor that occurs with increasing temperature. (Medium confidence),” the recently released fourth national climate assessment states.

In another study, Payne and a team ran simulations using 28 different global climate models to compare and contrast the behavior of atmospheric rivers in a historical world (1980-2005) versus a worst case under climate change future world (2070-2100). 

“What we really saw along the West Coast of the United States was we saw a broadening of the distribution of AR frequency,” Payne said. “So basically saying atmospheric rivers are going to be more variable with climate change. And we saw an increase in the number of years with many AR dates, so a lot more landfalling events at the end of the century.”

All of this adds up to there being more of a chance for the record floods of California’s recent past to become the new normal and for the most extreme events, like the ARkStorm, to become more likely by the end of the century. 

An aerial view of the damaged Oroville Dam spillway on Feb. 26, 2017. (Kelly M. Grow/California Department of Water Resources)

The State of Decay and Confusion

Mike Mierzwa has problems, lots of them. 

As the lead flood management planner for California’s Department of Water Resources (DWR), and a registered civil engineer, Mierzwa has to figure out how to protect California from the floods of today and the climate change-fueled ones of tomorrow. 

Mierzwa is just one flood planner in a state with 20,000 miles of levee and channels, 1,500 dams and reservoirs, managed by a nightmarish bureaucratic hodgepodge of state, federal and 1,300 different local flood management agencies.

A 2013 attempt by the DWR and U.S. Army Corps of Engineers (USACE) to round up flood infrastructure and its responsible parties across the state found that many flood control agencies didn’t even know exactly what they were managing. 

“Because of the fragmented ownership of infrastructure, no single agency in any county was familiar with all existing infrastructure across their respective county. In many cases, agencies did not even have a complete inventory of infrastructure that they owned and/or maintained,” the report states.

The biggest problem of all, though, is that California’s flood infrastructure is too old, ill-maintained, outdated and ill-equipped to deal with the worst floods of today and the even worse floods of tomorrow. The state’s flood protections rotted for decades after initial investment in the 1950s, 1960s and the 1970s.

In 2005, in the wake of the Katrina-induced flood infrastructure disaster in New Orleans, the U.S. Army Corps of Engineers inspected California’s flood control infrastructure and found that much of it was outdated for modern flood protection standards and in disrepair. 

That includes the concrete and earthen structures designed to contain the banks of rivers during floods, called levees, and dams and their reservoirs, which are designed to store and release floodwaters in a controlled manner. 

Many of the state’s levees, for example, were constructed from 1850 to 1920 with outdated engineering criteria and only sporadic improvements/fixes implemented from 1920 to 2000. 

In response, California’s state released a dire report warning of the threat to “aging infrastructure with major design deficiencies.”

“Unless California implements a strategic plan, the next major flood could easily overwhelm the state’s deteriorating 50-year-old flood protection system and have catastrophic consequences for our people, property and environment,” the report said at the time. “The State will continue to pay out millions, and potentially billions, of dollars every time a levee break occurs in the flood control system.”

Most, if not all of the levees, the state admits, aren’t at an adequate level to protect the more than 7 million people and $580 billion worth of resources at risk of worst case scenario flooding in the state. 

But the most recent example of decay, troublingly, comes not from the levees, but the state’s dams, the best-fortified structures in its arsenal of flood protections. 

Sure, the state’s dams are on average 70 years old, but their flood protection standard is much higher than the average levee’s; dams in California are built to withstand the maximum projected flood. 

Even the ARkStorm study itself said it was impossible, and even irresponsible, to speculate about which dams could fail in a megaflood.

But there were warning signs in the 2008 report. Sure, California’s dams might not completely structurally fail in the flood, but there’s more to a dam than a wall holding a reservoir full of water back. 

Experts in the ARkStorm report warned that other dam features could be “plausibly threatened” by a megaflood due to the decaying state of the infrastructure. Waterway experts recruited for the report in 2009 focused on scantily used dam emergency features, known as spillways, used as a last ditch effort to funnel excess water out and away from the dam before it overtops or fails. 

One unnamed expert in the report even ominously predicts, “When spillways sit untested for years, then are subjected to continuous flow for an extensive period, damage is possible or even likely.” Others took it a step further and found it “plausible” that a dam in the San Francisco area might experience spillway damage. 

Flash forward to February 2017, when, on the heels of a prolific atmospheric river, a mass of water had to be released from Oroville Dam’s reservoir into its spillway and emergency spillwayfor the first time ever. 

The force of the water, coupled with poor construction of the spillway in the 1960s and poor maintenance for years, ripped apart one of the spillways, threatening tens of thousands downstream.

The unexpected destruction of the spillway prompted fears that a “30-foot wall of water coming out of the lake” would rush in uncontrolled. Water officials didn’t know if the spillway would be destroyed altogether, putting the whole dam at risk for failure. 

Source: U.S. Army Corps of Engineers, California Department of Water Resources (2013)

Nearly 200,000 people were evacuated out of precaution, causing “pure chaos.” Some of the evacuated only had 30 minutes to grab essentials. Others weren’t afforded time to grab anything. 

That event prompted Gov. Jerry Brown to order the California Department of Water Resources’ Division of Safety of Dams to fast track the investigation of the 1,249 dams and spillways it manages across the state. 

In June and July, the DWS ordered 93 dams with similar designs as Oroville to “conduct more detailed evaluations” of dam structures like spillways for deficiencies and potential hazards. Some of the largest dams in the state were included among the 93.  

In September 2017, the Division of Safety of Dams published a report showing the condition of the state’s dams and the corresponding downstream risk to people and their livelihoods should dam failure occur.   

Dozens of the state’s 1,249 dams were given a rating of “fair” or below.

The DWS notes that dams rated in fair condition, despite having “no existing dam safety deficiencies for normal loading conditions” may still be at risk in the event of “rare or extreme hydrological events” like that of an ARkStorm.

Weather.com analysis of the report shows that 56 dams rated fair or poor had an “extremely high” or “high” downstream risk in the event of failure, indicating that homes or critical infrastructure could be flooded. 

Dams with “extremely high” downstream risk also face “considerable” loss of life and “major” impacts to critical infrastructure and property in the event of failure. 

Twenty-six dams rated fair or poor had an extremely high downstream risk. 

“We are in an era of aging infrastructure in California, which requires a stronger approach to evaluating and investing in the facilities that residents and the economy depend on,” California Department of Water Resources Director Grant Davis said in a statement issued in response to the report. 

Under the governor’s Four-Point Dam and Flood Protection Program, created in response to the Oroville crisis, all dam owners with higher downstream hazards are required by law for the first time to produce “inundation maps” and “emergency action plans” showing the potential downstream impacts from a given dam should the worst case scenario dam break occur. 

All dams mentioned previously with “extremely high” downstream risk must complete and submit emergency action plans by Jan. 1, 2018. 

The hope is to give emergency managers and the public a better idea of who’s really at risk and what that risk is should a dam be threatened.

Mierzwa said that emergency evacuation plans, flood impact maps and other actions, like raising houses and urban planning, are called non-structural flood protections. California’s aging physical infrastructure — its dams, levees and the like — are called structural flood protections in the world of flood management.

“Non-structural measures are ways to keep people away from the water, structural measures are ways to keep the water away from people,” said Mierzwa.

Mierzwa said that non-structural measures were “more effective than the structural measures when you get to these really extreme events” like the ARkStorm “because you’re giving people information, they can take whatever measures to protect themselves.”

“I’ll use myself as an example. I live in Yolo County, to the west of Sacramento County and I’m in the dam inundation area for United States Bureau of Reclamation facility Monticello Dam for Lake Berryessa,” said Mierzwa. “Now, I know I’m in the inundation area for my house, but the good news is I know that it takes nine hours, if there was a complete dam failure, for the water to get to my front door. I also know that I’m going to get a foot of water and my house is elevated so the water will basically be passing under there. So, I’m not worried about that dam failure out there.”

Source: U.S. Army Corps of Engineers, California Department of Water Resources (2013)

The problem is that the more than 7 million Californians at risk for flooding during the ARkStorm don’t have the same institutional knowledge as Mierzwa. The world of flood risk is complicated, perhaps too complicated to communicate the level of actual risk involved in a worst case scenario flood.

Dam failure flood projections are more predictable given flood managers’ knowledge of total capacity and potential discharge. Flood preparation and communication gets much more difficult when flood managers try to explain river flood risk, with topography, river flows and precipitation changes complicating forecasts. 

That’s part of the reason the DWR produces so-called “best available maps” (BAM), an interactive tool designed to allow Californians to see what sort of flood risk they’re living in. 

Floodplain maps are supposed to change based on improvements to flood infrastructure, or changes in projected flood levels due to urbanization, or climate change, which further complicates flood projections.

“With climate change, we know that the rainfall volumes are going to be increasing over time and so the nature of these maps are going to change over time too,” said Mierzwa. “Having maps out there is great, but the role of the state is to go through and update those maps to incorporate the latest information. We just can’t have 30-year-old maps.”

According to Mierzwa that’s a problem in California in areas with less funding or that are less proactive in non-structural flood management, like in Mariposa and Merced Counties where floodplain maps there are “probably older than many Americans.” 

Outdated flood maps put more people in actual flood zones and at risk of flooding.

“People will go buy property somewhere in an area and they’ll say ‘well it’s not in a floodplain map I’m okay.’ Well, what happened was there wasn’t enough money to go around so no one made a map for that area and then you get surprised when you get flooded.”

But if the goal is to help the public understand the true risk of living in a floodplain, even areas with updated maps fall short. The maps and every state, local and federal flood plan requires the public to understand some mind-numbingly confusing nomenclature used to describe the severity of floods, the strength of flood protections and even one’s risk of flooding: the “X-year flood.”

At face value, a 100-year flood sounds like a flood that hasn’t happened in a century, but that’s the furthest thing from the truth. Just because a 100-year flood happened last year, or even last week, doesn’t mean another one can’t occur, say, tomorrow. 

The nomenclature is really just a game of probabilities based on historical data, of so-called “return-periods” used to statistically quantify floods to show how rare a given flood is relative to the next. 

Hydrologists know, based on historical data, what specific rainfall totals and waterway levels produce lower and higher levels of flooding in a given area. Based on that, they know what the probability is for those flood levels to occur in a given year. For instance, the probability of a river reaching 20 feet in a flood is much higher than the probability of a river reaching 50 feet in a flood. 

With each step up in magnitude, from a 100-year flood, to a 200-year flood, to a 500-year flood, to a 1,000-year flood, the severity of a flood increases and the relative probability of it occurring decreases. A 100-year flood is one with a 1-in-100 chance, or 1 percent chance, of occurring in a given year. A 1,000-year flood only has a 0.1 percent chance of occurring in a given year. 

The Federal Emergency Management Agency (FEMA) identifies areas at risk of flooding, known as floodplains, based on those statistical probabilities and maps out flood risk into 100-year and 500-year zones. So, a person living in a 100-year FEMA floodplain should statistically expect their home to flood when a storm produces flood levels that only have a 1 percent chance of occurring in a given year. 

The problem with that statistic, Mierzwa says, is that most people live in floodplains for longer than just a year, so the actual odds of experiencing flooding are much greater over the course of the average 30 year mortgage. 

“Most people don’t use this number, but within 30 years, there’s a 1 in 4 (25%) chance that you will be flooded if you live within a 100-year floodplain,” Mierzwa said.

Back to those maps, because understanding flood risk gets even more complicated once you know the true risk of living in a floodplain. 

Not all flooding is created equal, according to Mierzwa, because the depth of that flooding varies depending on topography and other factors. Those FEMA maps also show flood depth in addition to flood risk. 

For instance, the potential 500-year floods of the Central Valley are much deeper, up to 15 feet in places, than those in Southern California. 

“In New Orleans (during Katrina) most of the fatalities were people who were trapped in their homes,” Mierzwa said. “The flood risk within the Central Valley is the same, it’s a deep floodplain, and if you have over three feet of water in a floodplain your chances of survival are cut in half. If it floods at night, you’re not getting out, you’re trapped in your home, you’re going to die.” 

Ultimately, this system of years, of probabilities and percents, is an imperfect attempt to make objective sense of the abstract and mercurial reality of personal flood risk. In reality, an infinite amount of factors specific to a latitude, longitude combination on a map, are changing at variable speeds independent and dependent of each other, increasing and decreasing flood risk from household to household. 

Climate change only complicates this variability by changing factors that play into flood risk.  

The further scientists glimpse into the future the less they’re able to objectively say about flood risk for a specific place. It’s the reason that the ARkStorm scenario described above simulated the impacts of a theoretical worst-case scenario storm in a pre-2010 version of California. 

All of this uncertainty is the reason that attempting to understand your specific flood risk in a future world with climate change is an impossible task. 

But scenarios like the ARkStorm give us a glimpse into what that future flood risk might look like in the modern world. In it, scientists projected 100-year, 200-year, 500-year and 1,000-year flooding spread out across the state, with 500-year level flooding commonplace in floodplains.

So, the takeaway should be this: The millions of Californians living in a floodplain risk destructive flooding now, and potentially even more destructive flooding in the future.

As scientists and flood managers said, it’s not a matter of if, but when, the next great flood occurs.

This aerial view looks overtop of the east levee breach on the Feather River near the community of Arboga in Yuba County, California on Jan. 3, 1997. (Dale Kolke/California Department of Water Resources)

Billions Spent, But Time is Priceless

Flood control managers have known about the threat of a California megaflood for decades.

The way Mierzwa likes to tell it, the awareness started growing after the Great Mississippi River Flood of 1993, which forced flood managers to dramatically rethink outdated, unscientific flood protection standards in urban areas of the country from the 1960s that still exist today.

Then the devastating atmospheric river fueled floods of 1997 hit California and flood managers in the state realized a similar type of flood could happen there. Katrina followed eight years later, and public interest in flood protection measures skyrocketed. 

Suddenly, levees and flood control permeated the public consciousness and there was a financial forum for potential flood protection measures. Starting in the 2000’s, California started pushing its climate change and flood actions into overdrive. 

Now officials know the state’s flood infrastructure is decaying and its flood plans are outdated. They know a catastrophic ARkStorm flood is coming. They know the threat of atmospheric rivers. They know climate change is making this flood disaster all the more likely. They just don’t know when. 

So the state created programs like the Integrated Climate Adaptation and Resiliency Program, which helps the state develop specific action plans to combat and protect against climate change impacts. 

Funding for climate change resiliency comes from sources like the state’s cap and trade program, which Gov. Brown recently extended through 2030. The program requires companies to buy permits to release greenhouse gases in attempt to reduce pollution. Recent estimates by the independent California Legislative Analyst Office project permit sales from the program could generate $2 billion to $4 billion in 2018 and up to $7 billion in 2030.  

Funds generated from the program are required by law to be used for projects designed to protect against climate change’s impacts, like future megafloods. Major flood management improvement projects are potential beneficiaries, including a potential expansion of the Yolo Bypass, a massive designated floodplain west of Sacramento designed to funnel water away from the city, Mierzwa said.

“Our governor has gone to the world and talked about how California is a climate leader and he is, his policies for all state agencies promote climate resilience to adapt for the future climate change impacts in our state, and we’re very proactive,” said Mierzwa. “But the dollars that are paying for all of this really come from the members of the public. And Californians at both the state and local level have really been proactive in about the past 10 years about recognizing that flood protection is an important expenditure as well.”

The onus doesn’t fall on Mierzwa and the DWR alone to fix California. Cooperation with both the 1,300 local flood management agencies, which are funded on a local level, and the U.S. Army Corps of Engineers, which is funded by Congress on the federal level, is vital to the overall picture of flood protection investment in the state. For example, together federal and local flood management sources are expected to shoulder 44 percent of flood protection costs in the Central Valley the next 30 years.

But a huge chunk of money for the most immediate water related needs, including flood protection improvements, is funded through state water bonds. 

Since 2002, through statewide votes, California voters have authorized the sale of four water bonds worth $24.058 billion. Each subsequent bond measure is greater than the last. There was $3.4 billion in 2002, two water bonds in 2006 worth a combined $9.5 billion and 2014’s $7.12 billion behemoth, which was trimmed down from $11.14 billion

Importantly, a large portion of the funds for these bonds aren’t allocated specifically for flood control measures and are instead used for parks, water conservation, clean water initiatives, groundwater reclamation and a litany of other water-related issues. 

Some, like natural watershed restoration, have so-called “multi-purpose benefits” that apply to more than one area of need, including, according to a water bond drafter, marginal, but likely insignificant improvements in flood control. 

Of the lot, proposition 1E was the only water bond in the last 15 years designated primarily for flood protection improvements. The bond set aside more than $4 billion specifically for such maintenance and improvements. 

Through the bonds, particularly Proposition 1E in 2006, the state could get to work on the area of most immediate need, where an ARkStorm could produce 15 to 20 foot floods: the Central Valley. 

“Bottom line we’re trying to prevent another New Orleans-like, Katrina-like kind of flooding,” Mierzwa said about the investment in the Central Valley. “When you’re looking at 100-year or 200-year floodplain in the Central Valley you can start seeing 20 feet of flooding or 15 feet of flooding. Those are the sure killers.”

At least $2.4 billion has been spent on flood management and protections improvements since 2007 in the Central Valley alone. 

That money has been used on things like refortifying hundreds of miles decaying levees in the Sacramento and San Joaquin watersheds. There’s also bigger, more ambitious ongoing flood protection projects, like the Folsom Dam Raise Project, which, along with other improvements, will reduce the risk of a catastrophic flood in Sacramento by raising the Folsom Dam so it can store more water upstream from the city. A much more comprehensive list of fixes/projects in the Central Valley is detailed in the recently released 2017 Central Valley Flood Protection Plan Update. 

But the most ambitious project to come out of it all is the so-called urban-level of flood protection standard, which mandates that, by 2025, all state/federal run flood protections in urban areas (pop. 10K+) in the Central Valley must have a 200-year level of flood protection. 

“In the Central Valley, when we had the flood in 1986 and 1997 the major damages that occurred — the life loss and the economic losses — really happened in rural and non urban areas, but we realized it could’ve easily been the city of Sacramento, or Marysville or Yuba City that could’ve flooded,” said Mierzwa. 

Because of the risk and cost associated with flood damages most private insurers don’t offer flood insurance for those living in floodplains. So most receive flood insurance from the National Flood Insurance Program (NFIP), which requires a 100-year level of flood protection to obtain insurance. 

Mierzwa said that the 100-year level of protection standard doesn’t realistically do enough to protect people, especially in a state like California, where 200- and 500-year level floods are growing ever more likely.  

“Somebody said, ‘let’s just stick with a 100-year flood’ and we’ve been living with that number even since,” said Mierzwa, who also administers the state’s coordination with the NFIP. “There was no science behind it in 1968. It was just something that we should do, and it’s become the defacto U.S. standard.”

The urban level protection standard is an attempt to build on the NFIP standard, a stepping stone to higher levels of protection. Each improvement in flood protection — through things like rezoning, raising houses, evacuation plans and levee improvements — earns an area credits and points toward rate reductions through FEMA and NFIP. 

The areas with the highest number of credits and points get the highest flood insurance rate reductions, so it’s an easy way to track the progress of the work that’s been done in Northern California over the last 10 years.  

Sacramento, areas of which didn’t even meet 100-year flood protection standards 10 years ago, is now a class 2 FEMA community, meaning it has the second highest level of premium reductions through the NFIP. Only a few communities across the country qualify for class 2 status. Roseville, roughly 20 minutes northeast of downtown Sacramento, is the first and only class 1 FEMA community in the country.

Work is still ongoing to achieve the 200-year standard just in urban areas in the Central Valley, Mierzwa said. It’s projected to be finished in the next 10 years and cost $4.5 billion. 

But that’s where progress on the state’s most ambitious project starts to unravel.

A 2017 analysis of a subsection of the Central Valley’s levees, the same ones being worked on the last 10 years, found that half of the levees in urban areas still didn’t meet current engineering standards. 

Then there are the rural towns and areas that still haven’t received any funding to reach the 200-year standard. Those levees need major work to catch up to their urban counterparts. Three-fifths of levees in non-urban areas in the Central Valley had issues that made them of high concern to the DWR, according to the same report. 

Mierzwa said it would cost $17 billion to $21 billion over the next 30 years for the entire Central Valley to reach to 200-year level flood protection standards. 

But not all areas of California seem interested in investing in systemwide increases in flood protection standards. In Southern California, the approach to dealing with the floods of the future is different. 

High Concern For Aging Infrastructure

This partial analysis of levees in the Sacramento and San Joaquin watersheds by the DWR shows the state of disrepair of levees in the area. 'High Concern' levees are those in the worst physical condition. Half of urban levees, and 3/5ths of rural levees in the area are of high concern. Source: California Department of Water Resources (2017)

Los Angeles County and Orange County have some of the largest areas of 500-year floodplains in Southern California. In the ARkStorm scenario those areas are at risk of deeper, deadlier flooding up to 10 feet.

And this is California’s most urban, population dense area. According to a 2013 analysis by the DWR, 338,100 structures and 48 percent of the population of Orange County, some 1.4 million people, are within in the 500-year floodplain in Orange County alone. Another 1.4 million people are within the 500-year floodplain in Los Angeles County. 

But flood managers in those counties said that, though they had explored a 200-year level flood protection standard around 2005, they were content to follow the federal 100-year level standard and that funding was better served funding specific flood improvement projects, operating and maintaining current facilities and educating the public on the risks of living in a floodplain, regardless of protections.

“For them (DWR) to start upping it (flood protections) and say they’re going to 200 (year levels) I get concerned they’re creating a false expectation for the public that they don’t need to worry about flood protection,” said Los Angeles County Public Works Director Mark Pestrella. 

“The fact of the matter remains that there is still is a floodplain, regardless of that protection. If you’re going forward in new areas, and you choose to do a 200-year-level of flood protection, you have to be able to tell a property owner you can buy a house here, here’s what your risk is going to be. But you still have risk. That risk never goes away. It’s always there.”

Pestrella said that the system in Los Angeles provides a range of individual flood protection measures above and below the 200-year standard, but that overall, the county’s system meets 100-year level standards. 

Orange County, on the other hand, is still struggling to meet the 100-year federal flood protection standard. 

In 2013, a joint report from the DWR and the USACE — which helps manages the maintenance of many of the levees and dams in the highly populated floodplains in Los Angeles and Orange Counties — found something troubling. 

“Orange County estimates that it would take 90 years at current funding levels for the county to fund the approximately $1.5 billion in projects necessary to bring its facilities to a 100-year (1 percent) flood recurrence probability design level,” the report said. 

The Orange County Flood Control District (OCFCD), which manages flood protections in the county, said that the deficiencies identified in the report were still accurate and that the district was using the information from the report to maintain and improve specific projects within its system. 

“The County of Orange is dedicated to improving our flood control system as funding allows,” an OCFCD spokesperson said.

In one specific project, a federal and locally funded study completed in 1975 found that the flood control system for the Santa Ana River, whose floodplain also stretches into San Bernardino and Riverside counties, only had 70-year levels of flood protection.

So, since 1988, the USACE, in tandem with the three local water authorities, has spent $1.3 billion on refortifying the areas flood protections in the so-called Santa Ana River project. The three-phase project even included building a new dam (Seven Oaks Dam), and once completed, will provide 190-year level flood protection for Orange County and other flood prone areas along the Santa Ana River, a massive improvement compared to 40 years ago. 

The work, nearly 30 years later, is still not complete. OCFD said that the total estimated cost of the Santa Ana is expected at around $2.3 billion and work, if federal funding comes through, should be completed by 2024. 

Federal funding and maintenance was a sticking point for both both Orange County and Los Angeles County. Flood control authorities there said the federal government hadn’t funded specific projects or necessary maintenance on the facilities that the federal government is supposed to maintain. 

Pestrella said, for instance, that Los Angeles’ greatest need is investment in maintaining the reservoirs that hold floodwaters back from the area, which have become choked with sediment, reducing their capacity to store water. Funding for that sort of maintenance is often not covered in the water bonds, Pestrella said. 

“For us, it’s investing in maintenance and operation rehabilitation, which the federal government has done a really poor job of,” Pestrella said. “Most of the problems you see are the federal agencies not maintaining the facilities properly. Not that they (the facilities) aren’t big enough, but that they’re not maintained properly over time.” 

Because Mierzwa said that the Central Valley had a more immediate need to improve some of the worst infrastructure in the state, most of the funding from the water bonds has gone there, leaving only relatively small amounts for Southern California. For instance, an OCFCD spokesman said that the district had received grants ranging from $5 million to $15 million in the last 10 years, far short of what’s needed to fill the $1.5 billion gap in funding needed to reach the 100-year standard countywide.

All told, Mierzwa said that the state needs $80 billion over the next 50 years to continue improving flood protections statewide. And $59 billion of that $80 billion is needed to tackle lingering issues in the rest of the state, outside the Central Valley, in places like San Francisco and Orange and Los Angeles Counties.

Even if all of California’s urban areas met the 200-year-level standard being pursued in the Central Valley, the level of protection likely isn’t enough. The 200-year urban level protection, as ambitious as it is, won’t realistically protect against the 500-year-plus level floods of California’s ARkStorm. 

“The 200-year standard is just like the 100-year standard, it’s a number that sounds good,” said Mierzwa. “It doesn’t work, statistically, that 200-year protection cuts risk of flooding down to 1-in-8, it’s more around a 1-in-6 chance over 30 years when you get to a 200-year level flood protection.”

So, if 200-year level protections won’t protect against an ARkStorm, against California’s realistic, climate change-fueled megaflood, why not move toward a higher standard? Why not 500-year levels of protection or beyond?

For Pestrella, investing in flood protections to 200 years and beyond isn’t a cost effective solution to combating climate change and its “incredibly improbable” potential floods. 

“Although, yes, we’re seeing things like Houston (Hurricane Harvey’s floods) happen, Houston is an incredibly improbable event that happened. Could you build facilities large enough to deal with that? Probably not,” said Pestrella. “So those folks that live in the 500-year floodplain would just need to be educated that occasionally, in a very improbable event, you’re going to see water in the home.” 

Mierzwa, on the other hand, seems to think that the Central Valley and other parts of the state could be re-engineered to protect for the potential 500-year floods an ARkStorm could produce if the state had the time. 

“The 200-year level was a stepping stone because we knew it would be cost prohibitive to get to what we’d prefer — which is an even greater level of protection — and we haven’t specified what the number is on that,” said Mierzwa.

There are no current pieces of infrastructure or plans with 500-year levels of protection just yet, Mierzwa said. But he said that, while there’s no official price tag on 500-year level of protection, state officials have been sniffing around a higher level of protection since all of this began in 2005. 

“Is it (500-year-level of protection) cost prohibitive? No. But is it (the 500-year standard) something that’s reasonable to accomplish in the next 30 years? Probably not.” 

The cost of 500-year level protection in just the Central Valley, Mierzwa said, likely wouldn’t be double that of the current $21 billion price tag for the area to reach 200-year levels. 

Mierza said the current 30-year planning horizon in the Central Valley is essentially the limit to public planning. Beyond 30 years, he said, you lose political support for funding through things like bonds because it becomes harder, with inflation and costs, to calculate your return on investment. 

“When you start doing the present worth of all those future benefits anything after 30 years becomes trivial in the present value of money out there, said Mierzwa. “From a fiscal standpoint the way Congress, state and even local municipalities look at it, you don’t look at investments after 30 years. It’s better to have that money in hand to spend on something now.”

And California would have to dramatically re-engineer itself to reach a 500-year level of protection and beyond, something that would take decades to accomplish, well beyond 2050 and that 30 year planning threshold. 

According to Mierzwa, because of the exponentially higher volume of water involved in a 500-year level flood, the current flood protection system would have to be rethought, with bypasses/channels upstream from major urban areas expanded to allow more water to pass through and then be funneled into new, larger designated floodplains away from people. The current system simply can’t handle that much water. 

“If we had 20 inches in two weeks a reservoir alone is not going to do it. There’s no way that we could have a channelized levee system convey those flood flows,” said Mierzwa. We’re absolutely going to require to have big massive bypasses and floodplains that can actually take some of that water on.”

Climate change is the cog turning independent of the state’s efforts through 2050. Global temperatures continue to rise, providing more moisture-laden fuel for atmospheric rivers. And the new, worst case scenario normal for atmospheric rivers, the one that brings more intense ARs, begins in 2070 in Ashley Payne’s research. 

California still needs at least $80 billion, and at least three decades, just to catch the flood protection system up to today’s standards. After 2050, it needs even more money and even more time to catch the flood protection system up to climate change’s worst projected flood. 

Floodwaters overtake The Islander Trailer Park near the San Joaquin River in Manteca, California, on Jan. 7, 1997. (Dale Kolke/California Department of Water Resources)

In 2018, “There’s No Choice”

A new chapter in California’s race against climate change has yet to be written, and once again, Californians will go to the voting booth to decide how the chapter begins.

Nearly $13 billion in water bonds will likely be on the ballot in June and November 2018, and if they pass, the bonds will provide a relatively small amount of much-needed funding for lingering flood protection fixes. 

June’s water bond, the California Drought, Water, Parks, Climate, Coastal Protection, and Outdoor Access For All Act of 2018, calls for another $4 billion in bonds for statewide parks and water projects, but only $1.3 billion of that is allocated for water projects, and further, only $550 million of it is set aside specifically for flood protection and repair. 

Of that $550 million, $350 million is designated to the DWR for flood management in the Central Valley, including $50 million specifically set aside for levee repairs in the San Joaquin and Sacramento Deltas. 

Some $100 million is available for grants for “stormwater, mudslide, and other flash-flood-related protections” and another $100 million for grants for “multibenefit projects in urbanized areas to address flooding” statewide. 

But the bill’s primary goal is investment in parks, particularly in communities without access to parks, leaving flood protection as a footnote. The bill’s author, Kevin De León called it “the single largest investment in the history of the United States to park-starved communities.”  

The proposed November bond, drafted by the former deputy secretary of the state Natural Resources Agency, Jerry Meral, aims to be “complementary” to the June ballot measure and “make sure that no critical problem was totally ignored,” filling in some of the gaps of flood protection funding from the June bond.  

The $8.877 billion Water Supply and Water Quality Act of 2018 would set aside at least $700 million for flood control related measures, Meral said. 

At least $100 million would go again to the Central Valley for flood protections, but there’s also other specific flood protection measures, including $200 million for Oroville Dam repairs and improvements and $100 million for other issues at dams and reservoirs on a local level, which Meral said will likely end up being used in Southern California for the crucial sediment removal projects in Los Angeles County. 

Combined, the two bonds would provide at least $1.25 billion specifically for flood protections, well short of the $80 billion needed statewide to reach the basic level of flood protection. 

Even if all six bonds from 2002 to 2018 were combined and used entirely for flood protections, a pool of $36.935 billion, that wouldn’t cover half the needed cost to fix California’s flood protections. 

And then there’s the yet-to-be defined price point on more advanced protections, beyond 200-year levels, which the state needs to realistically protect against an ARkStorm. 

The bonds aren’t enough, that’s why flood authorities in the Central Valley drafted a strategy for new funding sources, such as a potential state flood insurance program, that could provide a more reliable source of revenue to flood protections. 

“Bond funding by nature is short-lived, and this temporary boost is coming to an end … it is clear that current funding is starkly insufficient to meet public expectations for meaningful flood risk management. … To achieve sustainable funding for flood system investments, changes in funding … (are) required, as well as unprecedented funding commitments from current funding mechanisms at all levels of government.”

And at the local level, in Los Angeles County, Pestrella, the public works director, said the county is “blessed” to have local taxes that allocate funding specifically for flood protections and that officials there were considering a potential local tax increase in November to help bridge the gap in lackluster funding. 

But for now, California’s water bonds are the only real stop gap for the state’s immediate need to protect against the floods of the future. 

“There’s been a water bond in California every two and a half years since 1972 and they’ve all passed but one,” said Meral “Our thought is, ‘this is another one.’ We’re not going to tell anyone we’re solving all of these problems and you won’t need another one. You will need another one. You’re going to need at least one at least every four years for the foreseeable future.”

“We just have to keep investing. There’s no choice,” said Meral. “If we don’t invest we won’t have a society to live in.”

One of the 23,000 homes flooded during the 1997 floods in California. (Norm Hughes/California Department of Water Resources)