Hurricanes and Stormwater: What Managers need to Know

We’ve survived April showers, enjoyed our Spring flowers, and now hurricane season is (almost) upon us! Normally, when we think about hurricane preparedness, tasks such as boarding up windows, putting batteries in flashlights, and preparing an evacuation plan come to mind. We are taught to always be weather aware. All good ideas…and I’d like to add one to the list- it’s time to be stormwater aware!

Stormwater problems can be caused by more than just rain:

When we think stormwater, we usually think rain. Powerful tropical storms bring with them a host of other ways to reap havoc on stormwater infrastructure. For starters, the storm surges that accompany these events can be responsible for much of the damage caused by the storm. Did you know that rain totals in the NYC/NJ region during Superstorm Sandy were only 1 to 2 inches?  This amount of rain is usually a “meh” storm event. Still, this storm will go down in history due to the catastrophic flooding and damage to the region caused by a massive storm surge that accompanied the event.

Flooding in DUMBO Brooklyn during Superstorm Sandy (Image Suzie Housley, StormSensor)

In addition to storm surges, winds are also a major concern. Powerful winds can lead to power outages that halt operations at portions of your system that require electricity to function. High winds can also blow debris into or onto stormwater infrastructure, and they can cause clogs or block BMPs from functioning to control flooding and pollution as they were designed to do.

Suggested BMPs:

  • As a storm approaches (48 hours before landfall, to be safe!), perform an inspection of all vulnerable infrastructure. Detecting clogs or other issues before the storm arrives will decrease changes of failure once the storm hits the region.
  • Before rain begins, lower water levels in storage BMPs where possible; this will increase storage throughout the system.

Combined System or Not, SEWAGE is a Main Concern:

We all know that stormwater often carries pollutants such as heavy metals, bacteria, pesticides, and nutrients.  During a hurricane, risks of contamination increase, particularly those related to raw sewage. Power outages at lift stations and wastewater treatment plants add stress to systems already struggling to address blockages, storm surges, and increased rain totals. This combination often leads to combined and sanitary sewage overflows, meaning that runoff into local surface waters or water left flooding streets and sidewalks is likely to contain raw sewage.

Path of Hurricane Florence and Affected wastewater systems (Image, NOAA, WatrHub Inc.)

This no small issue. For example, Superstorm Sandy hit the NYC area in 2012 and caused 11 BILLION gallons of untreated sewage to be released, and an estimated $4.6 Billion in damages. And just last fall, the entire country watched as Hurricane Florence took aim at the East Coast, threatening a full third of the nation’s wastewater infrastructure.

Suggested BMPs:

  • Before a storm arrives, inspect all back-up generators to ensure proper performance during the anticipated event.
  • As the storm arrives, properly warn the public as to the hazards of sewage in polluted flood waters, waiting until after flooding occurs can risk unnecessary public health threats.
  • As the storm arrives, direct the public to fill bathtubs or otherwise store water in case of an outage, and ask that they conserve water during the event to reduce stress on the system.

NPDES May or May NOT apply:

Obviously, your safety and the safety of those in your community is the primary concern during a hurricane, but does that mean that NPDES requirements fly out the window? Not necessarily. Permits have different requirements in different States, and it is important to know what yours are. Most NPDES permits have exemptions for “natural disasters” and clearly (or, not so clearly in some cases) state the level of statistical storm you are required to treat. This can typically range anywhere from a 25-year to a 100-year storm. Which brings up another complicating factor. As climate change progresses and intense storms become more frequent, 50-year storms aren’t what they used to be! As more intense storms become the new normal, local municipalities may soon be expected to handle runoff for much larger events.

Suggested BMPs:

  • Know what the requirements of your NPDES permit are during extreme events.
  • Create a “Hurricane Checklist” for your stormwater management team to follow in advance of each storm. Review this list with your entire team prior to June 1.

We cannot prevent hurricanes from happening, but we can do our best to be prepared: 

The EPA provides a checklist that managers can use to “batten down the hatches”  when a hurricane is forecast, and recover once it has passed. However, the most vital preparation for the increasing threat of powerful hurricanes must be completed long before a storm starts brewing out at sea. Collecting local data, validating models, and updating design standards to reflect current (and predicted!) trends in climate change will be key in the movement towards achieving resiliency in coastal regions.

Forward thinking BMPs

At StormSensor, we are committed to offering affordable networks of real-time stormwater data. Our analytics platform is specifically designed to help those maintaining stormwater and combined sewage infrastructure manage immediate needs while planning for future demands.

If you’re interested in incorporating smart technology into your hurricane preparedness strategy, contact us and let’s get started!

 

About the author

Suzie Housley

Suzie has over a decade of experience in the Stormwater industry including both government and academic work. She leans on her experience to meaningfully interpret scientific studies and government policies to communicate a practical message. Suzie lives just outside Nashville, TN and gets outside whenever she can to explore nature with her husband and two small children.