How do we mitigate flooding like Florence?

To say that Hurricane Florence was bad would be the understatement of the century. Like most other people, my heart breaks to see so many suffer such incredible loss and tragedy, and it also fills with warmth at the outpouring of love and support from people across the state and the country. Disasters have a way of bringing people together and bringing out the best in good people.

sat image

NASA: Satellite image of Hurricane Florence just before noon on September 12, 2018.

If you’ve kept up with my Facebook posts or those of other meteorologists over the past 2 weeks, you know we did what we could to describe how much rain was possible from the molasses-in-the-Arctic-paced storm. Unfortunately, some people have trouble visualizing that much water or even believing it could happen again so soon after Hurricane Matthew inundated much of the same parts of the state. I’m not here to judge those who didn’t evacuate. I get it. I may not have made the same choice, but I get it.

While other people are debating the need for a better way to rate hurricanes, whether people took the warnings seriously, which viral photos were fake news, and the best way to get help to those in dire need right now (grassroots organizations or government bureaucracies), I want to focus on how to mitigate future disasters like Florence and Matthew. Some may think it’s too soon, but often, the best time to prepare for the next disaster is right after the last one.

What lessons can we learn from Matthew and Florence here in North Carolina, especially in the areas that suffered/are suffering severe flooding from both storms? What lessons can we learn from other regions that have suffered similar flooding like Houston did with Harvey? How do we lessen the impact of the next intense rain-maker of a tropical system?

There are some seemingly obvious answers to these questions such as improve dams and levees that breeched during the days-long rain, but those tasks only go so far against one to three feet of rain over the course of a few days. As creeks and rivers rise, the water is going to go where it wants to go, and we have to figure out how best to deal with it.

So, what do we know about where the water will go? Gravity takes water downhill, which is why low-lying areas tend to flood first. Streams also have a preferred route. Even when humans try to engineer a new route, stories tell of the rising water returning to its natural path, often resulting in flooding of the same area the engineers said wouldn’t flood again.

Owners of homes and businesses existing in a flood plain can and should buy flood insurance. If you live in a floodplain and have a mortgage, most likely your lender required you to buy flood insurance. If it isn’t a requirement, it’s still a good investment. However, the National Flood Insurance Program is being called insolvent by some. Storms with financially high costs such as Harvey have caused FEMA to borrow funds from the U.S. Treasury to pay out claims. According to the U.S. Government Accountability Office, “As of February 2018, FEMA’s debt stood at $20.5 billion.” Translation: the tax payers are going to pay for what the premiums can’t cover.

Raising National Flood Insurance Program premiums could help cover those costs, but it would prove detrimental to many of the people who live in floodplains. Often those people are on the lower-income side of the economic spectrum.

In an article published last week, Bloomberg described how Charlotte and Mecklenburg County in North Carolina are handling the potentially recurring costs of rebuilding after each flood. To summarize, they have been buying up properties that flood repeatedly, or are likely to flood, at fair prices as the funds are available. Once purchased, they demolish the buildings and do not allow development on that land. With that tactic, they are helping those sellers escape places they might not otherwise be able to sell because their potential for flooding is well known.

Flooded cars are another concern and one that can be easy to avoid by moving them to higher ground. During the weekend of Florence’s rainfall, the City of Raleigh opened the city-owned downtown parking decks for residents who live in low-lying areas to temporarily store their cars without a fee. It was a practical way to give people an option and a little peace of mind with regard to the security of their vehicles.

In the Netherlands, they have designed dikes, levees, walls and giant floodgates to hold back the sea, and many people point to their grand-scale technology as the perfect example of how to deal with rising sea level and coastal storms. Still, no solution is perfect, and trade-offs are necessary. While their floodgates and walls do their job, ecologists see problems such as toxic algal blooms arising from limiting the natural ebb and flow in the wetlands and bays behind those walls.

There are many other ways to mitigate flood risks including restoring wetlands in coastal areas, building floodways to relieve pressure on levees, restoring rivers to their natural channels, and raising the structural elevation of buildings. Public and private entities – towns and homeowners alike – need to do their own cost-benefit analyses to decide what works best for them. In the case of towns and cities, political support of the best plan is necessary since taxes will most likely – at least in part – be used to pay for it.


Note: I’ve included multiple hyperlinks in this post because some may want more information than I have space/time to include on the ideas listed.