Half of New Orleans is located below sea level. When water enters the area, the only way to remove it is with pumps. But what happens when the pumps fail? Water collects at ground level creating devastating floods; damaging infrastructure, homes and property. That’s precisely what happened during Hurricane Katrina.
Image: Japan's storm water drainage system. Credit: The Blog Below
Now, city engineers want to apply a different solution to this decades old battle by using permeable concrete to replace old sidewalks and streets in an area of New Orleans. Instead of having water run down the streets and collecting at the lowest level, they are building tiny air pockets into the concrete which allows the water to be absorbed, rather than running off into storm sewers. The initial rain is stored in the concrete until it is full, then flows through it, and into the ground below. The city of New Orleans partnered with Hard Rock Construction, Lafarge North America and the Make It Right Foundationfor this exciting new project.
With every rain event, several hundred thousand gallons of water will be saved from hitting the storm sewer. Frank Fromherz II, a New Orleans-based, civil engineer, has worked with Make It Right said "with pervious concrete, an urban drainage system can handle a larger rainfall. Initial runoff at the beginning of a storm never makes it to the city's drainage system, so for the overtaxed infrastructure in New Orleans, the benefits of using more pervious concrete would be huge."
Image: Permeable Concrete. Credit: TecEco.
The effects on public infrastructure are clear, but what does this mean for the environment? Storm water management practices are crucial for a healthy environment; they can impact localized water quality and quantity in receiving water systems. Natural receiving areas (rivers and lakes) are negatively affected by the sediment and contamination of urban storm water runoff. This also has a cascade effect on water handling systems downstream. Water drainage patterns have changed with our development practices and as a result we have flooding problems that have grown over time. Storm water management practices are clearly a critical component of sustainability. In fact, there is an entire section dedicated to it in the LEED certification program.
Finding solutions that are practical and useful in urban settings that limit the disruption and contamination of natural water flow benefits everyone. Although the cost of permeable concrete is approximately 10% higher than conventional concrete, on larger-scale projects, the city will be able to recover those costs through savings in their drainage budget. We look forward to seeing more innovative uses of concrete that dually serve a functional purpose in addition to a sustainable one!
Watch this informational video we found of Extreme Engineering:
