New Orleans’ use of porous pavement gradually expands

23rd March 2015   ·   0 Comments

By Susan Buchanan
Contributing Writer

Pervious or porous payday loans woodridge il concrete is used at a few sites around town to manage storm water. More applications are planned, and they’ll include half the sidewalks at the Lafitte Greenway Bicycle and Pedestrian Path, which should open this summer. The Make It Right Foundation homes in the Lower Ninth Ward have these honeycombed sidewalks and parking lanes, with more to be built this year. The New Orleans Bio­Innovation Center on Canal St. and Xavier University of Louisiana’s Convocation Center have pervious parking lots.

In urban areas, the benefits of pervious applications include water table and aquifer replenishment, fewer pollutants entering waterways, and less need for drain pipes and retention ponds, Brent Magee, a certified pervious installer and president of Mandala Concrete, LLC in Mandeville, said last week.

“Pervious concrete looks like a Rice Krispie treat in texture and color,” he said. A mix of coarse aggregates, cement, water and little or no sand, this porous material is 15 to 25 percent voids or holes. Three to eight gallons of water per minute can pass through one square foot of it. Pervious concrete is usually applied over a bedding layer made of crushed stone aggregate. Bedding supports the concrete, stores payday loans in lodi water and helps treat runoff.

In addition to reducing a city’s drainage demands, pervious pavements are cooler than regular concrete and kinder to trees. “In south Louisiana, pervious concrete allows roots of oak trees to breathe and keeps them from cracking pavement surfaces,” Magee said. “And on porous asphalt streets, noise from traffic is lower than it is on standard asphalt.” Porous asphalt hasn’t been installed in south Louisiana to date, however.

A pervious parking lot costs about 15 percent more to build. “But you’ll save on repairs and maintenance so it’s more economical over its lifespan,” Magee said. This concrete can be power-washed or vacuumed. “In New Orleans, rain usually cleans out matter stuck in the pavement’s pores, however,” he said.

Mayor Mitch Landrieu’s administration supports the use of pervious concrete. But most of the city’s big recovery projects don’t have any porous components. That’s partly because of red tape from government funding sources. And one reason that standard asphalt is widely used here instead of permeable asphalt is that its load-bearing capacity for vehicles is greater.

But Magee said the strong asphalt lobby in this oil-and-gas state means lenders fees standard asphalt is sometimes chosen when a permeable application would have been better. Asphalt pavement is about five percent asphalt cement, a petroleum product that leaches from streets.

Half of the sidewalks at Lafitte Greenway will be pervious concrete, Lt. Colonel Mark Jernigan, the city’s public works director and a former deputy commander at the U.S. Army Corps of Engineers in New Orleans, said last week. The rest will be standard concrete.

A total of $77,000 was budgeted to install 1,300 square yards of pervious concrete in the $9.1 million Lafitte Greenway project, Hayne Rainey, spokesman for Mayor Mitch Landrieu, said last week. The 2.6-mile stretch, running from the French Quarter to Bayou St. John, is funded by federal Disaster Community Development Block Grants and Louisiana Recreational Trails grants.

When asked, Jernigan said pervious concrete won’t be used in the Southeast Louisiana Urban Flood Damage Reduction Project, funded by the Army Corps and the city’s Sewerage and Water Board. But that’s not because of an Army Corps decision. “The Corps’ designs are based on Department of Public Works standards” set by the city, Army Corps spokesman Rene Poche in New Orleans said last week. The loan curtailment price tag for the SELA work on Claiborne, Jeffer­son, Napoleon and Louisiana Avenues is about $300 million, Poche also said.

Major repairs and repaving under the city’s Recovery Roads Pro­gram, funded by Federal Emer­gency Management Agency, don’t include pervious asphalt. FEMA funding created some constraints, Jernigan said.

But the feds, particularly the U.S. Environmental Protection Agency, support the use of pervious pavement when it’s appropriate. The EPA recognizes per­vious concrete as a Best Management Prac­tice to help engineers cope with storm water. Pervious concrete over an aggregate bed reduces storm water runoff volume, rates and pollutants, according to the agency. Permeable pavement can transform areas that were sources of storm water into treatment systems.

That’s important to EPA because it wants local governments to reduce hydrocarbons and other pollutants that storm runoff sends into rivers and streams.

Magee said the open-cell structure of pervious pavement provides a medium for aerobic bacteria to break down pollutants, including those seeping from cars and reaching waterways.

In the rating system known as LEED, or Leadership in Energy and Environmental Design, developed by the nonprofit United States Green Building Council to evaluate structures, pervious concrete can earn lots cash advance rock springs wy of points toward platinum, gold and silver designations, Magee said. LEED points are earned by meeting sustainability goals rather than by product usage, and a building’s pervious installations can contribute to several LEED objectives.

The city has learned the advantages of pervious sidewalk and parking lanes from homes built by actor Brad Pitt’s Make It Right Foundation. In mid-2012, the city began a $2.7 million paving project in the Lower Ninth Ward to test pervious concrete. “It’s been the pervious demonstration project with the biggest impact so far,” Jernigan said. “And it has helped that area deal with storm water.” More pervious concrete will be incorporated in the city’s green infrastructure ahead, he said, and added that it’s encouraging to see that Xavier, the BioInnovation Center and other entities have used it.

“Our company paved the pervious sidewalks and driveways at Make it Right over the last two years,” Magee of Mandala Con­crete said. “Another 15 to 20 homes will be built there this year, and we’ll do their sidewalks and parking areas. We have a pervious parking-lot job coming up at the Volunteers of America building on Canal St.”

Mandala installed express payday loans columbus oh the pervious lots at Xavier and the Bio­Innovation Center. Magee was told that his company will be hired to pave the Lafitte Greenway sidewalks though he hasn’t received a contract yet. As far as he knows, he’s the only Louisiana-licensed contractor to install pervious concrete. He learned his craft in Oregon. A few contractors licensed by states other than Louisiana have done small pervious projects here, he said.

Installation methods for pervious and conventional concrete differ. Because of its low water content, a pervious concrete mix hardens quickly and needs to be poured right away. A screed or metal bar is used to level pervious concrete after it’s poured. Pervious concrete is usually cured for a week to make it hard, versus three days to a week for standard concrete.

The $2.5 million Greater New Orleans Urban Water Plan, released in September and funded by Louisiana’s Office of Com­munity Development, supports pervious concrete for drainage, Hayne Rainey said last week. But for now, the city lags Chicago, along with several cities in the Pacific Northwest and California, in its use of porous pavement.

This article originally published in the March 23, 2015 print edition of The Louisiana Weekly newspaper.