Stormwater Infrastructure and Management: Unsafe for Human Contact

by Evan Isaacson

As millions of Americans in Houston and throughout Florida and Puerto Rico are acutely aware, the most dangerous aspect of a hurricane is the water. In Houston, the 50 inches of water that fell over the course of a few days broke records and overwhelmed the city’s flood control system. In Florida, Hurricane Irma’s storm surge ravaged coastal communities hundreds of miles up and down the Atlantic and Gulf coasts. And in Puerto Rico, Hurricane Maria dumped more than two feet of rain in some areas, generating floodwaters more than a dozen feet high in low-lying areas throughout the island.

The pathway of waterborne devastation was different for each of these storms. But as the winds faded and the waters receded, one thing that remained in each of these locations was hazardous and even lethal contaminants left behind by the floodwaters. Thousands of Americans returned to their homes and communities, wading through inches, even feet, of water that carried anything and everything that you would expect to find in sewers, basements, parking lots, and factory floors.

A top official at one of the several trade associations that lobby for municipal water and sewer systems told Bloomberg News in the wake of Irma that “there’s no sewer system in the world that can be built that’s completely leak proof.” Behind this specious statement, however, lie some important questions that must be asked about the state of America’s water infrastructure and our preparedness for a new and more extreme reality.

Costly Lessons

The combined severity of Hurricanes Harvey, Irma, and Maria may be unprecedented, but the type of damage caused by these storms is, of course, nothing new. Just one year prior, when Hurricanes Hermine and Matthew briefly passed over and around Florida, respectively, the storms caused more than 250 million gallons of sewage to overflow and spill into nearby communities.

It may take some time to estimate the total volume of sewage overflows in Florida more recently caused by Irma, but more than 100 spills or releases were reported to the state by local governments across Florida in just the first several days following the storm. A geospatial analysis of EPA data combined with federal estimates of the extent of Irma’s storm surge shows that major wastewater treatment plants from Tampa to Naples on the Gulf Coast and from Miami to Daytona Beach on the Atlantic Coast may have all experienced coastal flooding during the storm.

The map on the left shows the extent of coastal inundation caused by Hurricane Irma as estimated by NOAA, while on the right is a smaller scale map of the Naples-Ft. Myers metropolitan area showing major wastewater facility dischargers, such as large sewage treatment plants. In both maps, light blue areas represent inland inundation from the storm, while darker blue areas are inundation of intertidal zones and estuarine wetlands. Light green squares on the right are all major wastewater facilities, while larger red squares are sewage treatment plants located in areas projected to have been inundated during Irma’s storm surge.

While researchers and the insurance industry continue to tally up the damage from the 2017 hurricanes, it is imperative that our elected leaders and agency officials take heed of the lessons from these recent catastrophic storms. Just because a perfectly leak-proof sewage system cannot be designed does not mean we can ignore the awful condition of our nation’s water and sewer infrastructure or defer action on creating more resilient urban landscapes. Nor can we afford to continue pretending that our flood zone maps accurately reflect the true nature of flood risk. If these maps had any basis in reality, then perhaps the majority of Houston estimated to have flooded during Hurricane Harvey would have been shown to be located within the 500-year floodplain.

Many EPA-regulated industrial sites in the Houston area containing toxic pollution are located in FEMA flood zones, while many other low-lying facilities are not included in these zones drawn by government officials. These EPA- regulated sites are coded by elevation in the above map, with dots ranging from dark green at the highest elevation to red at the lowest elevation. Dark blue areas show the 100-year flood zone and light blue show the 500-year flood zone. As the map reveals, many low lying sites at risk of inundation are not in a FEMA flood zone.


Regulatory Progress on Flood Control: A Slow Drip

The history of flood control in the United States is generally a history of growing federal involvement and increasingly large engineering projects to keep water from spilling over riverbanks, reservoirs, and levees. Within cities, storm sewer systems eventually emerged as an engineering solution to channel the ever greater volumes of rainwater down the drains and into the nearest waterway, as quickly as possible.

For obvious reasons, this practice of using urban streams and rivers as an extension of the local sewer system implicated the Clean Water Act. One of the most consequential and underappreciated points in America’s history of flood mitigation is the 1987 amendments to the Clean Water Act. The Environmental Protection Agency was required by that law to establish a new permitting program for municipal separate storm sewer systems (“MS4s”) to reduce the impact of discharges from urban outfalls into the waterways around which most Americans lived and from which many draw their drinking water.

We are now more than 45 years from the enactment of the Clean Water Act and more than 30 years from the 1987 amendments, but, with some exceptions, our storm sewers look much the same today as they did in the middle of the twentieth century. There are three primary reasons for this stagnant pace of regulatory development.

The first reason is that EPA and the state permit writers have largely dragged their heels in developing new permits and moving cities, counties, and other municipal MS4 permit holders from one five-year permit cycle to the next. A second and closely related reason is that our cities and counties have been successful in marshalling their considerable political clout to lobby permit writers to maintain this sluggish pace, thereby delaying or avoiding costs associated with the modernization of MS4 permits and incorporation of the latest technologies into local permit implementation plans. Finally, in fairness to cities, states, and EPA, the menu of options for addressing pollution carried by rainwater has historically been much more limited and slower to develop than the “end of pipe” technologies that have long existed for most wastewater dischargers regulated under the Clean Water Act.

But over the last decade, the range of technological options for improving the quality of polluted urban runoff and reducing the quantity of storm and flood waters has improved substantially. The evolution of this technological progress and increasing availability of new solutions is reflected in a series of guidance documents developed primarily by EPA’s Office of Water.

Initially, EPA gave cities and states a pass when it came to addressing the pervasive problem of stormwater pollution through stormwater permits. But throughout the first and second terms of the Obama administration, EPA’s guidance evolved in a way that pushed state and local governments to consider addressing the problems caused by the impervious surfaces that drain to the MS4 system. EPA accomplished this by drawing a clear and direct link between stormwater permit pollution limits and the pollution reductions called for in watershed restoration plans required by the Clean Water Act, known as Total Maximum Daily Load (TMDL) requirements. This shift occurred largely because the development of “green infrastructure” techniques and technologies had expanded dramatically, opening new opportunities for MS4 permit holders to help meet water quality goals.

The problem, however, is that technological innovation and EPA’s evolving expectations for the way in which cities should be controlling polluted runoff and floodwaters have both outpaced the enforceable standards and pollution limits that state permit writers have actually placed in the MS4 permits. If permit writers made sure that each MS4 permit was renewed on schedule every five years, they could ensure that each and every new permit reflected the latest technologies and their ever decreasing costs. That is how the 1987 Clean Water Act amendments were supposed to work in order to ensure cities and counties were protecting their communities to the “maximum extent practicable” from urban runoff.


Pointing Fingers Rather than Taking Action

Unfortunately, many state and local governments and water utilities, and the variety of associations that represent them, have employed the same tactics as any private sector or industrial trade group to combat regulatory progress. Local governments and utilities have sued, lobbied, and advocated to halt the modernization of permits and regulations. Accelerating water infrastructure upgrades to protect water quality and public health, it seems, is a far less important goal for many local leaders than paring back municipal budgets. This fiscally conservative, if shortsighted, strategy to deal with environmental, public health, and flood control challenges is typically the one most appealing to local officials, at least until catastrophe — generally foreseeable — strikes.

In the weeks after Harvey hit, Houston Mayor Sylvester Turner publicly feuded with Texas Governor Greg Abbott over the need for Texas to open up its “Rainy Day” fund to help rebuild the city after yet another major weather event hit the city. Turner also urged the state to begin investing in a series of multi-billion-dollar projects to hurricane-proof the city and the area’s oil and gas infrastructure. The mayor rightly pointed out that the $12 billion cost to build this new system of dikes, levees, and a massive storm gate would be a tiny fraction of the cost to rebuild the areas of Houston that would be devastated again and again after each new hurricane.

But it’s hard to propose an utterly sensible investment like this, or even to point the finger at the state, when you don’t have clean hands yourself. Houston’s famous resistance to city planning and its permissive stance toward development and the vast resulting expanses of pavement have been important contributors in causing repeated and regular flooding in the city, amplifying the impact of hurricanes. Being one of the most vulnerable cities in the nation to tropical storms and recurrent flooding should be reason enough to switch to smarter growth policies or to join other cities investing in green infrastructure and more climate-resilient urban landscapes.


The Storms’ Toxic Legacy

In one of the most important postmortems of Hurricane Katrina, the National Academy of Engineering published an article examining the toxic contaminants stirred up by the hurricane. The authors noted that the greatest threat of exposure to hazardous substances came not from the obvious stew of chemicals seen swirling in the floodwaters, but from what evaporated or settled out from those floodwaters.

Long after a hurricane passes, the sediments it unearths and disseminates are left coating the ground in and around homes and businesses in the affected area. And these toxic sediments also settle between the cracks of our regulatory system, with no obvious regulatory tools for controlling their impact.

These chemicals may have been regulated at one point under our pesticide, insecticide, or solid waste disposal laws, or they may have seeped through the ground of a regulated hazardous waste site. The substances may have been deemed pollutants of concern as part of an impaired waterway restoration plan under the Clean Water Act. Or perhaps the sediments blew from a stockpile or site that had failed to properly undertake dust control or good housekeeping practices required under one of several environmental laws.

Regardless of their journey through the regulatory process, once toxin-laden sediments are mobilized in a storm they simply become part of the ambient environment ready to imperil the health of local communities, wildlife, or ecosystems the next time the wind blows or water runs its course. Clearly, current regulatory standards are lacking and insufficient to protect storm-ravaged communities from the storm’s long-lasting impacts.


What Should Be Done?

Local Jurisdictions Should Invest in Green Infrastructure

The significant recent advances in technological development for controlling polluted urban runoff provide more than just a powerful new tool for MS4 permit writers looking to devise new stormwater permit conditions and meet lower pollution limits. As it turns out, this developing suite of stormwater best management practices, which collectively fall within the label of “green infrastructure,” are helpful for achieving a variety of community goals beyond stormwater management.

Municipal officials around the United States are beginning to invest in green infrastructure for many different reasons. Some cities and counties are greening their urban landscapes to tackle stormwater pollution, reduce sewer overflows, improve urban air quality, reduce energy use, beautify streetscapes, increase property values, or provide recreational amenities for residents, all while providing a boost to the local economy with construction and engineering jobs that cannot be exported.

Going forward, jurisdictions will likely continue to invest heavily in green infrastructure for a powerful new benefit: resilience in the face of a changing climate. By virtue of the fact that many green infrastructure projects are designed to soak up rainfall, they end up converting the city’s impermeable layer of pavement into a spongier landscape. Bioswales, green roofs, and sidewalk trees allow urban neighborhoods to handle the more frequent and intense storms that are now battering communities around the United States. In conjunction with coastline protection projects and large-scale “gray infrastructure” approaches to controlling runoff, green infrastructure programs have become an important tool in the climate adaptation toolbox for progressive urban jurisdictions.

Of course, cash-strapped cities are often reluctant to commit substantial resources in their capital budgets to address pollution from stormwater or sewer overflows, or to adapt to a slowly changing climate. Any one of the benefits afforded by green infrastructure alone may not be enough to convince elected officials to make the politically difficult choice of raising or diverting public funds from other pressing needs. In fact, all of these reasons together may not even be enough motivation to convince some short-sighted elected officials either.

The Federal Government Should Prod Local Government on Green Infrastructure

However, the important point is that these jurisdictions should not really have much of a choice in this matter. Congress made the decision three decades ago that the Clean Water Act necessitates a local response to water quality concerns from polluted urban runoff. Local programs to control stormwater became a federal concern (and a state concern due to delegations of permitting authority) through the MS4 permit requirement. Thus, as stormwater control technologies advance, state and federal permit writers should be nudging local governments towards greening their urban environment and infrastructure as permit renewals continuously modernize the MS4 permit.

Some large urban jurisdictions have been subject to federal consent decrees to eliminate sewer overflows under Long Term Control Plans. As green infrastructure projects have become an accepted method for reducing sewer system infiltration, these Long Term Control Plans provide another regulatory or enforcement tool to push urban jurisdictions to unlock the myriad benefits of greening urban areas.

Thus, EPA and state environment agencies play an important role in moving local governments and utilities forward in creating a more resilient urban environment. We need EPA to hold states accountable for modernizing MS4 permits through timely renewals and strict oversight of permit conditions. An active and vigorous EPA can and should push urban jurisdictions to commit to investing in green infrastructure. Cities and counties that do so will fare better in handling future hurricanes than Houston, Jacksonville, or San Juan did in 2017.