Learning from the Past & Planning for the Future

“A Response Boomtown, Flood Town” (Excerpt)

By Michael Bloom & Steve Stagner

Originally printed on Feb. 6, 2017 in TribTalk & ProPublica

City of Houston flood czar Steve Costello meets with Memorial City residents. (Michael Stravato for The Texas Tribune/ProPublica)

In December, the Texas Tribune and ProPublica jointly published “Boomtown, Flood Town,” an article on flooding and development in the Houston region. Since 1989, approximately 23,000 of the 1.5 million houses in Harris County – or 1.5 percent of the homes – have flooded from rainfall (not including coastal surge). In addition, the region experienced fewer than 60 of 9,500 days of high water during the same period – representing 0.6 percent of the time. With the exception of deaths due to basement parking lot flooding during Tropical Storm Allison, all fatalities, have resulted from people driving into flooded underpasses and not from structural flooding. The risk from underpass flooding is being addressed with enhanced warning lights, gates and signage. Below-ground parking areas have been retrofitted with flood-proofing facilities, seals, and doors.

In the early 1900’s, Houston-area drainage districts assumed that a 4-foot-deep ditch with a 4-foot-wide bottom would be sufficient to prevent flooding. Gradually, this standard began to change. Drainage systems designed after 1986 work amazingly well.  They include below-ground storm sewers sized to carry the rain from two-year events (with a 50 percent chance of happening every year).

In spite of its flood-prone nature, Houston has flourished and people still continue to choose to live here. According to the U. S. Department of Commerce, the Houston region’s gross domestic product has grown from $241 billion to $503 billion during the period from 2001 to 2015.

Hydrologists, floodplain managers, and engineers in the private and public sectors have done a remarkable job in reducing flood damages in our region. We will continue to make progress in this area while addressing development, changes in rainfall patterns, and population growth in a sustainable manner.

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