‘Paradigm shift’ on flooding emerging after Harvey

In October 1957, three days of heavy rains pushed the Turia River out of its banks in Valencia, Spain, causing floods that destroyed thousands of homes and businesses and killed at least 81 people.

In response, Spanish authorities moved the river.

The diversion of the Turia from the heart of Valencia to its outskirts - the dry riverbed is now a popular park — was a remarkable feat of engineering that took nine years. It was, by any measure, a bold step to protect a beloved city.

That strategy is not an option in the Houston area, crisscrossed by at least 20 bayous and streams that can become raging torrents in a heavy spring thunderstorm. Yet, public officials and flood-weary residents, determined to avoid a recurrence of the devastation caused by Hurricane Harvey a year ago, are calling for the same kind of audacious thinking that informed the decision in Spain.

“We’ve got to take our head out of the sand and recognize that we have to do things differently,” Houston Mayor Sylvester Turner said recently.

The need for transformative strategies to break the cycle of flood/rebuild/flood again has been a persistent theme of the post-Harvey public conversation. The term “paradigm shift” appears three times in an April report by the Greater Houston Flood Mitigation Consortium, a group of academic researchers.

“The problem in the past,” said Christof Spieler, the consortium’s project manager, “is that not long after a flooding event, we forget about flooding again, and then don’t think about it until the rain starts.”

In the months after Harvey, area leaders discussed new, bolder strategies in several policy realms: imposing stricter limits on development in flood-prone areas; dramatically increasing buyouts of homes that have flooded repeatedly; investing in major projects, such as a third detention reservoir or a canal near the downtown confluence of White Oak and Buffalo bayous.

A key test of the community’s commitment to change, Turner and others agreed, would come with Saturday’s referendum on $2.5 billion in Harris County bonds for flood resilience projects. Paying off the bonds would require many residents to pay higher property taxes, always a tough sell.

Even before Saturday’s election, local leaders could cite evidence that attitudes were shifting after Harvey. A notable example was the Houston City Council’s 9-7 vote in April to require all new development in floodplains be built two feet above the projected water level in a so-called 500-year storm. Politically powerful real estate interests had lobbied against the proposal.

“That represented a game-changer,” Turner said, “especially when you had the Realtors, the developers, many contractors that were down at City Hall saying, ‘No, don’t do it.’”

A determination to do things differently also is surfacing on a smaller scale, within neighborhoods where many residents still are struggling to recover .

All 164 homes in the Somerset Place townhome development off Memorial Drive took on water from Harvey. None had ever flooded before, said Jim Muckle, the president of the resident board who has not finished repairs to his own home.

As Muckle and others assessed the need for repairs to the development’s common areas after Harvey, they decided to go beyond replacing dead plants and repairing chipped pavement. Residents agreed to increase their association fees to regrade the property, improving its drainage, Muckle said.

“We didn’t want to leave ourselves with the same bevy of issues that we had before Harvey,” he said. “I have yet to meet with a single homeowner who does not agree with this alternate path.”

On a regional level, consensus has been harder to achieve.

Some argue that the incremental approach represented by the city’s stricter floodplain rules falls short of what’s needed. John Jacob, a Texas A&M University professor who runs the Texas Community Watershed Partners program, suggested in a recent essay that 100,000 homes should be removed from floodplains at a potential cost of $20 billion: “That would buy us some real resilience,” Jacob wrote, acknowledging that his idea would take “a generation or two” to achieve.

Whether the region’s leaders are prepared to turn entire, long-established neighborhoods into green spaces is questionable. Still, many public officials, civic leaders and others who have dealt with Houston floods for decades sense something different about the reaction to Harvey, which caused an estimated $125 billion in damages and flooded more than 150,000 homes.

“At the end of the day, I am more encouraged by what I’ve seen in the last six months than from any other flood we’ve ever had in Houston,” Phil Bedient, the director of Rice University’s Center for Severe Storm Prediction, Education and Evacuation from Disasters, said on a recent Houston Public Media program. “Things are moving.”

Questions remain, though, about how the region’s leaders can apply the lessons learned from floods that have pummeled the area with increasing frequency and intensity. Flooding has been a feature of life in Houston almost since the city’s founding in the 1830s, but a flurry of particularly severe floods, starting with Tropical Storm Allison in 2001, has led to sustained public attention on the problem.

Allison caused $2 billion in damage to the Texas Medical Center, one of Houston’s crown jewels. Harvey, a more severe storm, had little impact on the medical center because its hospitals, clinics and office buildings were protected by a sophisticated Brays Bayou warning system developed by Rice University scientists.

“Because of that great feat of engineering, we had cars floating down the streets of the medical center, and all of our hospitals remained active during Harvey and afterward,” said Bill McKeon, the medical center’s chief executive officer. Getting specific information in advance enabled the medical center’s leaders to take action, such as closing underground storm doors.

The report by the flood mitigation consortium estimated that a similar system could be put in place for all 22 of the county’s watersheds for $5 million to $10 million - less than the cost of a single detention basin.

Why was that not done in the 16 years between Allison and Harvey? Perhaps because no single official or agency had the authority or resources to make it happen.

“Most of the things we need to do to really address flooding are things that we as a region have already figured out how to do and have already been doing to some extent,” Spieler said. Lapses in applying this knowledge, he said, have “been a case of resources and will as much as anything else.”

As the consortium’s report notes, development regulations vary among cities and counties, and even within the same watershed — an area that drains into a particular body of water. Contradictions exist within the same jurisdiction; Houston’s floodplain ordinance and its building codes, for example, impose different requirements on the elevation of building slabs.

Millions of people live in unincorporated communities in Harris and surrounding counties, but county government lacks enforcement tools such as the authority to “red-tag” a building to stop construction if the structure does not comply with flood-protection rules. A county’s only option is to take the owner to court.

Turner said Houston and Harris County cooperate effectively on disaster response, but he suggested the Texas Legislature may need to create some sort of regional “entity” with authority to ensure that jurisdictions do not work at cross-purposes.

“Flooding is not just a city issue or a Harris County issue; it becomes a regional issue,” Turner said. “Ultimately, for that sort of regional coordination with any degree of enforcement, that’s going to require legislation from the state.”

Any regional flood resilience strategy also must account for the influence of climate change, which experts agree has made intense storms more frequent while rendering maps defining regulated flood hazard zones — the so-called 100- and 500-year floodplains — all but obsolete.

A 100-year floodplain is an area expected to flood during a storm that has a 1 percent chance of occurring in a given year. In a 500-year floodplain, the chance is calculated at .2 percent.

The floodplain maps are based on historical rainfall data, and a Rice University report released this month noted that several big storms in the past 20 years have changed the database: “The bottom line is that current estimates of 100-year and 500-year floodplains are no longer accurate. They simply are too small given recent storm experiences and rainfall trends.”

Government scientists have estimated that in central Harris County, the amount of rain that defines a 100-year storm has increased from 13 inches to 16 to 17 inches over 24 hours. And the ongoing effects of climate change, the Rice report says, will make it even more difficult to continually update the data and resulting maps.

“Instead, we should consider how to get ahead of the issue, something we can only do if we stop arguing about whether the climate is changing and instead start analyzing and understanding this serious problem,” the report states.

In the end, the quality that distinguished Harvey from all the floods that came before it — the sheer scope of its devastation — may be what prevents the same thing from happening again.

Muckle, the Somerset Place resident leader, said he and his neighbors may have fallen into complacency after previous floods that did not affect them personally. Now, they know better — and so do thousands of others around the area who found themselves mucking out their houses for the first time.

The force of that collective experience is powerful.

“This was much more universal in scope and scale,” Muckle said of Harvey. “It all feeds into this constant reminder of what we have gone through and are still going through in many ways. It feeds the will and desire and motivation.” 

Editor's Note: The Greater Houston Flood Mitigation Consortium is funded and supported by the Cynthia and George Mitchell Foundation. To download the consortium's report, please click here.


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