Rain, rain go away: climate change, extreme weather events, and floodplains

One of my lines about policy by elected officials is sort of along the lines of the Churchill quote about the US:

You can always trust America to do the right thing.  After she has exhausted all other possible alternatives.

Policy and practice is mostly about doing whatever you can to avoid the reality of economics (e.g., if you restrict housing supply, prices go up) or disaster (e.g., if you build in flood plains and buildings get flooded, but instead of saying don't build in flood plains, people rebuild and/or flood insurance helps pay to do so).

There are almost too many examples to count of problems resulting from flooding because of buildings in flood plains impacted by hurricanes, extreme rain, etc.  And decided actions to try to avoid acknowledging and addressing the required changes.

-- "Flood Insurance Program Increasingly Underwater as Payouts Shatter Records," Scientific American

A recent example is in Arlington County, where Four Mile Run was devastated by last week's extreme rain on Monday July 8th ("After years of talk — and flooding — Arlington residents demand fixes to storm drain system," Washington Post).  People in the article are quoted about Arlington taking a long time on dealing with the need for more robust stormwater drainage systems.

Alexandra Lettow was near tears as she described the losses her family suffered in Monday’s flooding to neighbors and county officials gathered at a home in Arlington’s Waverly Hills neighborhood.

Destroyed this time were the family’s appliances, the heating and air-conditioning system, the hot water heater, a couch, her son’s Xbox, a television and more. It was at least the seventh time the neighborhood had flooded in 19 years.

“We took a home loan out last year to repair the basement from the last flood,” Lettow said. “We have no more money, and we have mold growing down there.”

Arlington officials on Saturday said initial reports put uninsured residential and business losses at more than $4 million.

Um, 7 floods over 19 years is an indicator of a structural problem.

But with rains more and more extreme, the amount of piping and water storage capacity necessary to capture the water to prevent flooding is almost immeasurable. It's certainly very costly to try to build a hard system (pipes and storage). DC's building both hard infrastructure and soft (water capture and diversion from drainage collection systems), but in extreme events it may not be enough. For example, the National Archives after terrible flooding in the past has emergency water barriers, which deployed last week ("The National Archives' floating flood wall helped dodge disaster," Post).

But at the same time, even though it's an extremely hard decision to make, buildings in known flood zones ought to be taken removed. The county and individuals can't keep trying to put things back together only for the problem to repeat. Remember, insurance policies don't typically cover this kind of water damage, especially in areas known for flooding risk.

-- FEMA Flood Risk Maps


Another regional example is Ellicott City in Howard County, just outside of Baltimore, where over a short period the commercial district experienced flash floods twice, each with loss of life. Dealing with this, with the loss of some great historic building stock, has roiled local politics there ("Experts weigh in on development's impact on Ellicott City flooding," Baltimore Sun; "A Historic River Town Confronts a Flooded Future," CityLab).

1. I've written about Tulsa.

The city frequently experienced floods on the Tulsa River, many of which resulted in death and property damage. In 1984, after flooding which resulted in 14 deaths, the city created a Department of Stormwater Management and developed a Citywide Flood and Stormwater Management Plan, which provides for specific improvements across the city.

The primary focus of the plan is removing buildings from the flood plain and converting these spaces to greenways and parks as a way to absorb flooding while minimizing damage. The plan has been frequently updated--another iteration is underway--and since 1990, no structure built before 1987 has been damaged by flooding.

-- "Stormwater Management // After 10 Years, How Is the new department doing?," Tulsa World, 1994
-- "In Tulsa, a National Blueprint for Managing Floods as Cities Grow and Climate Changes," NPR

Although more recently, they don't make the planning documents that easy to find. In other words, you'd think you could find them in a central place on the city website... nope.

-- Phase II Stormwater Management Program (SWMP) for Tulsa County, Oklahoma
-- STORMWATER TORMWATER MANAGEMENT CRITERIA MANUAL, City of Tulsa

2.  And Florida, where post-Hurricane changes to building codes ("Hurricane Andrew prompted better building code requirements," Business Insurance) have made buildings more resilient in the face of extreme storms, although as memories of past disasters fade, there is backsliding on the regulation ("Florida’s building code is tough, but Michael was tougher. Is it time for a rewrite," Miami Herald).

3.  USA Today reports, "Trump tax reform: Don't expect tax break on losses from severe storms," that recent changes to the tax laws make it harder to deduct unexpected losses from flooding.  And that a federal disaster declaration is necessary to be eligible for tax loss deductions.  That seems a bit extreme to me.  State-sanctioned declarations ought to suffice.

4.  The New York Times had a story, "'We Cannot Save Everything': A Historic Neighborhood Confronts Rising Seas," about disaster planning for historic buildings in Newport, Rhode Island, vis a vis the Atlantic Ocean.

There is a nice multimedia graphic showing how the basements of buildings are being rebuilt to accommodate flooding.  ... although that means you can't use the basement for anything else.

5. This year's floods in the Midwest have even overwhelmed cities like Davenport, Iowa, which also took steps similar to Tulsa, and only allowed development along the waterfront, like a baseball stadium and parks, designed to accommodate floods ("Deadly Flooding From Michigan to the South Damages Homes, Sends Mississippi River to 157-Year-High in Davenport, Iowa," Weather Channel).

The city chose to not build a levee system but to rely on water barriers and flood walls. 

Conclusion.  Like what Tulsa started doing 35 years ago, more places are going to have to make hard choices about dealing with pre-existing development in floodplains in river and stream watersheds, on riverfronts, and on coastal waterfronts.


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Frankly, we have a similar issue because while we don't live in a flood plain, it turns out our neighborhood includes at least one "buried creek" and there is a high water table.  Now with more frequent and extreme rains, if the drain in our back porch gets covered in leaves and debris, water can build up (very quickly) and seep into the basement.

It's abetted by "bad perc" (percolation) in our backyard.  The ground is very compacted and water pools during a hard and fast rain.

This is after we already put in a French drain system because of problems with the high water table and water coming into the basement from under the house through the seams in the concrete floor (hydrostatic pressure)-- but we only put it in on three sides (oops).

We lamented why didn't the previous owner put in the French drain system instead of us paying for it?  But rain events probably weren't that extreme in the 50 years she lived here.

They are now.  Regularly.