On August 15, 2017, President Trump issued an executive order to expedite federal infrastructure-related decisions by allowing only 90 days for permit decisions and cutting back on flood safety requirements. Enthusiastic Republicans hailed the step. For instance, Rep. Ralph Abraham (R-LA) said he was “thrilled by Mr. Trump’s decision.” He dismissed catastrophic flooding in Louisiana the previous year as an “isolated event,” saying that the “bigger threat . . . is from costly regulations.” Ten days later, Hurricane Harvey hit Texas and western Louisiana.
An ounce of prevention is worth a pound of cure, or so goes the maxim. It could hardly be more apt than in the case of flood mitigation projects, since investments in resilience pay for themselves many times over when natural disasters strike. For instance, according to a recent report:
Recent studies have indicated that every dollar spent building or improving buildings to comply with the newer codes saves four dollars in damages. . . . [T]he return on investment in building to the upgraded codes parallels similar investment in efforts to create a more resilient infrastructure. Studies have indicated that it’s possible to receive a 6:1 rate of return on federal grants that have been provided for in mitigation efforts, including enhancing the infrastructure.
Current federal requirements for resilience in buildings and infrastructure are spotty and in need of an overhaul.
Current Resilience Requirements
Levees and seawalls
More than 100,000 miles of levees stretch along the waterways of the United States, including about a fifth of all U.S. counties, many of which are owned or operated by states, localities, or private entities. Earthen levees are constructed from compacted soil that is typically covered with grass, gravel, stone, asphalt, or concrete to help prevent erosion. Floodwalls, which are generally found in urban areas, are made of concrete. Levees require active maintenance such as removing trees or other vegetation, repairing concrete damage, or filling in animal burrows.
The Government Accountability Office (GAO) reported that the federal government does not have a program that oversees all levees across the nation, and no national standards for levee safety. Instead, the Army Corps of Engineers (the Corps) attempts to oversee only the 15,000 miles of levees involving federal construction, maintenance, or rehabilitation. Under a 2014 law, the Federal Emergency Management Agency (FEMA) and the Corps were also supposed to establish voluntary federal safety guidelines and a hazard classification system based solely on the potential consequences associated with a levee’s failure, as opposed to the likelihood or probability of a levee failure.
As of mid-2016, the agencies had made little progress on some tasks and no progress on others required by the statute, which they attributed to lack of resources. Apart from some work on incorporating FEMA information into an Army Corps database, the situation was bleak:
The agencies have taken no action on the remaining key national levee-safety-related activities for which they were responsible and have missed several statutory deadlines for developing guidelines and reports. For example, the agencies took no action on . . . the voluntary national levee-safety guidelines, due June 10, 2015; or a report, due June 10, 2015, that was to include, among other things, recommendations for legislation and other congressional actions necessary to ensure national levee safety. Additionally, according to agency officials we interviewed, the agencies have no current plan for implementing the remaining activities.
Other federal infrastructure
In 2015, President Obama issued an executive order requiring greater flood precautions for federally funded infrastructure, especially such critical facilities as hospitals. Although leaving room for some alternatives, the Obama order authorized three main approaches to flood risk management for federal infrastructure:
(i) the elevation and flood hazard area that result from using a climate-informed science approach that uses the best-available, actionable hydrologic and hydraulic data and methods that integrate current and future changes in flooding based on climate science. . . . ;
(ii) the elevation and flood hazard area that result from using the freeboard value reached by adding an additional 2 feet to the base flood elevation for non-critical actions and by adding an additional 3 feet to the base flood elevation for critical actions;
(iii) the area subject to flooding by the 0.2 percent annual chance flood.
Just days before Hurricane Harvey, Trump repealed the order, thrilling Representative Abraham and restoring a previous standard dating from the Carter administration. Section 6 of Executive 13801 states, “Executive Order 13690 of January 30, 2015 (Establishing a Federal Flood Risk Management Standard and a Process for Further Soliciting and Considering Stakeholder Input), is revoked.”
The Obama order seems to have had three fatal flaws from Trump’s perspective: It made construction more expensive, it was issued by Obama, and it mentioned climate change. In the long run, American taxpayers will find themselves paying out more in disaster relief for buildings they helped pay for in the first place because the government failed to require proper flood precautions.
In February 2018, the U.S. Department of Housing and Urban Development (HUD) quietly reinstated some of the Obama requirements for post-hurricane housing funding. Chapter VI(B), § 32(e) of the Notice setting forth requirements for disaster recovery community development block grantees provides:
All structures . . . designed principally for residential use and located in the 100-year (or 1 percent annual chance) floodplain that receive assistance for new construction, repair of substantial damage, or substantial improvement . . . must be elevated with the lowest floor, including the basement, at least two feet above the base flood elevation. Mixed-use structures with no dwelling units and no residents below two feet above base flood elevation, must be elevated or floodproofed, in accordance with FEMA floodproofing standards at 44 CFR 60.3(c)(3)(ii) or successor standard, up to at least two feet above base flood elevation. . . . All Critical Actions . . . within the 500-year (or 0.2 percent annual chance) floodplain must be elevated or floodproofed (in accordance with the FEMA standards) to the higher of the 500-year floodplain elevation or three feet above the 100-year floodplain elevation. If the 500-year floodplain is unavailable, and the Critical Action is in the 100-year floodplain, then the structure must be elevated or floodproofed at least three feet above the 100-year floodplain elevation.
HUD also included a directive for grantees to take "continued sea level rise" into account. Chapter VI(A) § 7 requires grantees to:
Promote sound, sustainable long-term recovery planning informed by a post-disaster evaluation of hazard risk, especially construction standards and land-use decisions that reflect responsible floodplain and wetland management and take into account continued sea level rise, if applicable; and coordinate with other local and regional planning efforts to ensure consistency. This information should be based on the history of FEMA flood mitigation efforts and take into account projected increase in sea level (if applicable) and the frequency and intensity of precipitation events. (emphasis added).
However, other federal infrastructure spending remains subject only to the Carter-era rules.
The hurricane season of 2017 should be a wake-up call. We need to get serious about flood risks and infrastructure. Those risks are only going to increase as sea level rises and extreme weather becomes more common.
In February 2017, the Oroville Dam in California faced a risk of failure after heavy rains, leading to the evacuation of 188,000 people. The dam’s emergency spillway came near to collapse. As reported in the Sacramento Bee:
One day after water started running over the emergency structure, the hillside had eroded so badly that dam officials feared the lip of the emergency spillway would crumble, releasing a "wall of water" on communities below the dam. That necessitated the evacuation. Faced with imminent disaster, dam operators then dramatically ramped up water releases over the main spillway, which lowered lake levels to the point that water stopped flowing over the emergency spillway.
Although the practice of dam safety has certainly improved since the 1970s, the fact that this incident happened to the owner of the tallest dam in the United States, under regulation of a federal agency, with repeated evaluation by reputable outside consultants, in a state with a leading dam safety regulatory program, is a wake-up call for everyone involved in dam safety. . . . Challenging current assumptions on what constitutes “best practice” in our industry is overdue.
The federal government regulates the safety of only a small proportion of dams in the United States. According to the American Society of Civil Engineers, in 2015, there were more than 15,000 dams classified as “high-hazard potential,” a number that had increased by a third since 2005. The federal government owns less than 5 percent of the nation’s dams; the remainder are generally regulated by state governments. The federal government issues dam safety guidelines, but they are not mandatory. The national flood safety program is established by 33 U.S. Code § 467f and includes provisions for training and other support of state programs. According to FEMA, nine states (Alabama, California, Florida, Georgia, Indiana, Iowa, Kentucky, Vermont, and Wyoming) lack the power to require owners of high-hazard dams to prepare emergency action plans covering evacuation and other responses. Clearly, more needs to be done to ensure the safety of our country’s dams.
Estimating maximum flows
Even putting aside the impacts of climate change and land use change, there are a lot of uncertainties about the designation of 100-year or 500-year floods, which are key to planning for important infrastructure such as dams and levees and also for flood maps. For inland flooding, estimates are based on hydrological gauges in streams. (Hurricanes, on the other hand, are fairly rare events, so the database for them is inherently limited.) There may be a limited number of gauges in some areas, or they may not have been in operation very long. Also, gauges may be inaccurate, particularly in periods of high flow. Efforts are made to adjust for some of these issues, for example with comparisons to gauges in nearby areas. But this involves judgment calls.
In addition, we don’t have a theoretical basis for predicting the statistical distribution of river flows over time. The federal government did a study and found that, of the standard distributions used by statisticians, one called the Pearson Type III distribution with log transformation worked the best for fitting the data on high stream flows (i.e., floods). (This is basically a normal “bell curve” that has been stretched in one direction, or “skewed.”) But this is an approximation since we don’t know the true shape of the probability distribution. So the statistical method being used is only approximately right to begin with.
By definition, increasingly rare events are increasingly unlikely to be found in the record of the time period for which we have data. That means that there’s going to be a lot of uncertainty about high-end estimates, which involve rare events like 500-year floods. For example, in a situation studied by the National Research Council in 2000, the expected discharge for the 100-year flood was 4,310 cubic feet of water per second (cfs), the upper confidence limit was 6,176 cfs, and the lower limit was 3,008 cfs. So basically, what we know is that there’s a 90 percent chance that the 100-year flow would involve somewhere between 3,008 cfs and 6,176 cfs, a difference of a factor of two.
What Should Be Done?
Congress needs to fully fund the levee safety program
Trump needs to reinstate Obama’s infrastructure flood safety executive order
If President Trump does not revive the Obama order, Congress needs to enact legislation to do so.
The dam safety program needs to be revamped
FERC needs to assume responsibility for regulating and inspecting the subset of non-federal dams with the highest hazard levels.
FEMA needs to be more explicit about uncertainties in flood modeling and work toward improvements
FEMA should prioritize research on improved modeling techniques that incorporate climate change and landscape changes that increase flood risk. FEMA and other agencies should also take a precautionary approach to federal infrastructure planning, using a margin of safety to account for uncertainties.