N.C. should build past heavy flooding

Future anthropologists will quizzically reflect on our hurricane history and marvel; a nation which could land a spacecraft on an asteroid could not mitigate flood damage.

One nation with a history of flooding that has succeeded in mitigating flood damage is Holland. Some homes and streets are constructed on what we would perceive as floating docks with flexible utility connections. The structures become dynamic under flood load and can rise and fall as the flood elevation rises and subsides.

Solving some of the catastrophic flooding, coastal and inland, requires the skills of Naval Architects and Coastal Engineers. The home builders may need to acquire some ship-building skills. Some solutions are incredibly simple as providing buoyancy tanks and moorings under the mobile homes. (FEMA can only buy from the willing grantors in the NCFMIP zones.)

Impoundments such as Lake Crabtree and Falls Lake routinely mitigate downstream impacts. Eastern North Carolina has no such protections. The model could be replicated in Eastern N.C., probably at a lower cost than the cumulative damage. The resulting lakes would provide recreation opportunities and water quality improvements. The spoil could enforce levies in areas such as Princeville.

I recently asked a Professional Engineer if he thought that the simple addition of headwalls and wing walls would have prevented some of the highway wash-outs from Hurricane Matthew. He replied yes! The damage from Hurricane Katrina could have been mitigated had the policy makers included levee reinforcement as suggested by engineers. The front-end load of prevention outweighs the future damages. You can pay now or you (or succeeding generations) can pay later.

One of the objectives of the Transportation Improvement Program was to locate four-lane highways within 90 miles of everywhere in the state. Road construction creates dams which obstruct the natural flow of water. Many drainage system guidelines only required to be designed for the 10-year storm.

Conventional wisdom states that if you did not design for the 10-year storm, the cost of development would be prohibitive. Creative building and site development, accompanied by prudent stormwater mitigation strategies, building codes and development regulation can help mitigate flood damage, and we may be able to continue to build in these areas.

During my 62 years I have seen at least two 100-year storms. Said storm definition may have been created prior to the increase in road building and municipal development which creates higher runoff coefficients. (Many development codes now require detention and retention of stormwater.)

When settlers moved off of the barrier islands and migrated to areas such as the Promise Land in Morehead City, they capitalized on elevation and small structure size (low-wind load). The advent of mega coastal homes with their wind loads are an invitation to disaster. Even the size of highway guide signs is limited by wind load.

North Carolina has the intellectual capital to solve the perpetual “flooding” problems. Do we have the resolve to protect those downstream suffering from wind and flooding? While flooding captures our attention, who is planning for the next drought as the economically successful state increases our population?

Let us not embarrass ourselves to future generations.

This story was originally published October 20, 2016 at 5:49 PM with the headline "N.C. should build past heavy flooding."