In November, Congress passed a bill backed by local representatives Kevin Brady and Sheila Jackson Lee to study, among other things, why flooding seemed to be increasing in Harris County. Local environmentalists think they already know the answer: urban sprawl.

Flood waters last year submerged many Houston freeways

Researchers said that flooding is just one of the negative impacts of concrete-happy urban planning. With the amount of impervious surfaces increasing in Houston at an alarming rate, billions of gallons of water each year have nowhere to go.

This is no news to nearby residents and commuters who traverse the I-10/Beltway 8 exchange, which frequently ends up underwater after a heavy storm. Larry Dunbar, an engineering consultant for the Galveston Bay Conservation and Preservation Association who specializes in flooding and drainage said expanding the freeway was a terrible idea. Not only would the added lanes gobble up a large amount of land that could absorb rainwater, it would render the freeway impassable for the many streams it crosses. The streams can only overflow, he said, threatening nearby homes and businesses.
Promises from the Texas Department of Transportation to build detention ponds have not silenced freeway expansion opponents. “We’ve seen this before. They tell you, ‘don’t worry, we’ll take care of it,’ and frankly, we don’t trust them,” Dunbar said.

For years, environmentalists have fought construction of the Grand Parkway, a third loop that would stretch 140 miles across seven counties to encircle the Greater Houston area. Most heavily contested is segment C of the parkway, which crosses a frequently overflowing Brazos River.

Pat Tovsen, a Sierra Club member and vocal opponent of the Parkway criticized TXDOT for trying to save money by building an elevated parkway rather than bridges. She said that bridges would allow for sheet flow of rainwater while the elevated road would essentially act as a 10-foot high dam across the watershed.
“It’s my money,” Tovsen said. “If they’re going to build this thing they might as well do it right because it will be my money they’ll have to spend to fix the road when they find out it doesn’t work.”

Freeway opponents also fear that expansion will encourage commercial development along the roads, which will slice through much-needed green space, compounding the flooding problem.

Environmentalists urged city planners to focus funds on improving public transportation rather than adding lane miles of highway at a furious rate. Currently however, Houston business and political leaders support plans to expand every major existing freeway and to add several more.

Elie Alkourhi, a drainage specialist with TXDOT said he was advised by the agency’s lawyer not to discuss the freeway projects with CEC.

The American Rivers report linked other water problems to urban sprawl. Because water that runs off impervious surfaces would normally recharge aquifers and surface waters, urban sprawl could be a leading cause of drought across the country. Researchers estimate that in Houston, an average of about 30 billion gallons of groundwater infiltration is lost each year as it runs off developed land.

Pollution is also a problem compounded by sprawl, but not just because urban pollutants are washed through storm drains into rivers and lakes.

Researchers found that an increase in the amount of driving, a characteristic endemic to sprawling communities, caused higher levels of polycyclic aromatic carbons in some watersheds. Higher levels of PAH, a group of suspected carcinogens, were linked to the increase in miles traveled because of tire wear, crankcase oil, roadway wear and car soot and exhaust.

To download the full report, visit http://www.americanrivers.org/landuse/sprawldroughtreport.htm.