Home > Water

Stormwater Control Lessons in the Age of More Extreme Weather

Stormwater Control Lessons in the Age of More Extreme Weather

Debris Removal, Repair and Mitigation of Drainage System Damages, and FEMA Funding

By Matthew Burnette

Water is a cornerstone of life and commerce as well as something we need to manage, specifically through drainage infrastructure. Thus, water presents both opportunities and challenges for localities that are required to control its flow in a great many forms.  Managing water, wastewater, and stormwater are foundational services that local governments provide to their citizens and as such should be a top priority for elected officials and municipal staff.

The issue of properly managing stormwater has become more complex in recent years due in part to the confluence of aging infrastructure and more extreme rain events. Like all levels of government, localities across the country face deteriorating infrastructure in their communities. Our infrastructure is in desperate need of investment. In a 2017 report from the American Society of Civil Engineers, the group estimated that the United States needs to spend trillions of dollars to address all the needs. Capital investment for the nation’s wastewater and stormwater systems will require an estimated $300 billion over the next two decades to fix. Although this level of funding is highly unlikely, especially given budgetary constraints at all levels of government, these numbers illustrate the degree to which aging infrastructure presents a challenge.

Combine that reality with the increased frequency of bigger and more damaging weather events. The National Oceanic and Atmospheric Administration (NOAA) has reported that tropic storm intensities and rainfall rates are expected to rise across the globe in coming years. These extreme rain events tax aging drainage systems to the max and beyond.

Significant rainfall in a short period of time, whether from a hurricane or another storm, will tax already strained systems and could lead to disastrous consequences.

Draper Aden Associates’ field staff recording the dimensions of eroded slope protection near a stormwater pipe outfall. Slope protection helps to prevent further erosion that can encroach on residential dwellings or other important infrastructure.

Exploring the impacts of Hurricane Florence (2018) on the drainage system in the City of New Bern, North Carolina offers instructive insights. The City of New Bern’s drainage system includes over 80 miles of open ditch network for conveying stormwater runoff. Like many municipalities across the country, New Bern’s infrastructure was aging and even included terra cotta piping. Hurricane Florence left a lasting impact on the City by overrunning the stormwater system, flooding the City, and wreaking havoc on the drainage network. Among the storm’s last impacts was the significant amount of debris, such as sediment and vegetative debris, it deposited in the City’s drainage system. This debris greatly reduced the capacity of the City’s drainage system and significantly increased the likelihood of future flooding. After an extreme weather event, it is common for municipalities like New Bern to face complex challenges on multiple levels.

Recognizing the need to repair and improve its drainage system, the City of New Bern is focused on a multitude of solutions to address all damaged elements.

After evaluating the damaged pipe systems constructed of historic materials, such as terra cotta, engineers have recommended replacing those systems with more modern materials, such as concrete, metal, or HDPE.

Additionally, the City of New Bern is exploring mitigation options including upsizing existing pipes to account for current and projected future development in hopes of preventing future damage and flooding during extreme weather events. Thus, undertaking mitigation efforts can yield additional benefits to support further development in a community.

Furthermore, the City of New Bern conducted an exhaustive review of its drainage system and identified areas with erosion concerns. Areas of erosion will be stabilized using a variety of methods. One mitigation option for severely eroded embankments includes the construction of new retaining walls.

Finally, the City of New Bern is exploring debris removal strategies to restore the capacity of the drainage system to the pre-disaster condition. These strategies include the removal of sediment and debris, primarily vegetative including hazardous limbs, trees, and brush, from the City’s drainage ditches.

Draper Aden Associates’ field staff verifying the dimensions of a roadway culvert. High stormwater flows have led to the undercutting of the headwall surrounding this culvert.

These solutions highlight best practices for localities to consider when repairing and improving stormwater infrastructure that is damaged in extreme rain events. Although these solutions offer valuable lessons, there’s a key consideration that has yet to be addressed: funding.

Many localities face a variety of budgetary constraints and the additional money needed to address unexpected repairs and improvements is not always readily available in local budgets. Fortunately, funding support is accessible through the Federal Emergency Management Agency (FEMA) after extreme weather events, such as a hurricane.

Securing FEMA resources for water control repairs and improvements requires both diligence after a disaster and proactive preparation in advance of a disaster. Most localities understand the importance of carefully following FEMA guidelines. For localities that haven’t had to apply for FEMA funding in recent years, it’s crucial that you familiarize yourself with the agency’s new delivery model. The ways in which FEMA wants information packaged and delivered has changed. It’s wise to review this process before disaster strikes or partner with a consultant that has experience with the new delivery model.

Most importantly, though, FEMA is increasingly evaluating requests for funding based on a municipality’s maintenance of their infrastructure before an extreme weather event or other disaster occurs. In short, what you’re doing now will have a significant impact on your ability to access FEMA funds in the future.

What is FEMA looking for?

The agency prioritizes localities that have established and thorough maintenance plans of their drainage systems. How are you maintaining your system on an annual basis? How are you evaluating the system’s performance and adjusting your proactive maintenance efforts?

Maintaining accurate records is crucial as well. Be sure to capture and update routine maintenance in detailed maintenance logs. Demonstrate that your locality has been budgeting money to ensure proper system maintenance as well. These records can make a big difference for municipalities. A town, city, or county that has an established and well documented record of routine maintenance for its stormwater system is in a much better position to receive FEMA funds compared to a municipality that is not conducting routine maintenance, such as cleaning out pipes or mowing around drainage systems.

The biggest recommendation for municipalities is to ensure that you’re maintaining your drainage systems. Accurately track and log that maintenance while ensuring that you’ve budgeted appropriately to continue that routine maintenance.       

Although no one has a crystal ball that allows us to see the future, localities around the United States should be prepared for a new reality of more extreme rain events that can have destabilizing effects on aging infrastructure, especially water control and stormwater drainage systems. Recognizing this likely scenario, you can act now to prepare by ensuring proper maintenance of your existing systems. This proactive approach also will benefit you after a disaster by increasing the likelihood of receiving FEMA funding to repair damage.

Matthew Burnette, PG, CFM is a Senior Project Manager with Draper Aden Associates, a Mid-Atlantic engineering, surveying, and environmental services firm. Based in the firm’s Raleigh, NC office, he manages water resources and stormwater projects for state and local governments. He can be contacted at mburnette@daa.com.