Fill Used for Flood Resilience Scrutinized Post-Harvey

Texas home developers’ practice of using dirt to raise homes above a flood plain is drawing increased scrutiny as experts question flood resilience measures after Hurricane Harvey.

Some experts argued using dirt, or fill, reduces storage for stormwater and worsens flooding, the Houston Chronicle reported.

The practice creates a perception of safety from flooding that might not be justified, said Houston attorney Jim Blackburn.

Using fill to lift property out of flood plains is “legal, but arguably unethical,” Blackburn said. “It sends the wrong message.”

Harris County requires developers to offset fill by creating an equivalent amount of water storage. The county’s rules reduce adverse impacts but don’t eliminate them, according to Larry Larson, director emeritus of the Association of State Floodplain Managers.

“The big problem in the Houston area is, you start using fill, you can fill so much that there’s no storage left,” Larson said.

Bank executive Don Hickey’s home flooded after Harvey despite being raised 5 feet (1.5 meters) above the 100-year flood plain, which refers to land perceived to have 1 percent chance of flooding in a given year. A post-Harvey analysis by Hickey and other residents found most of the flooded homes from Harvey were built on land raised using fill.

Since 2015, the Houston area has experienced three 500-year floods, events with a 0.2 percent chance of occurring any given year. Nearly three-quarters of the 204,000 Harris County homes and apartments damaged during Harvey were outside the 100-year flood plain, according to an analysis by the newspaper.

“The 100-year flood plain is obsolete,” Blackburn said.

The issue is part of a broader debate about responsible development after Harvey. Last week, the Houston City Council narrowly approved stricter development rules proposed by Mayor Sylvester Turner.