The U.S. Geological Survey recently put together a model that estimated the amount of impervious parking lot coverage in the United States. 

According to the report, 5.5% of all developed land in the lower 48 is covered by parking lots. That’s close to 26 billion square feet of surface area that is impervious to stormwater. All of this impervious surface area contributes to stormwater pollution and localized flooding when it rains.

With U.S. cities responsible for discharging up to 10 Trillion gallons of polluted water into clean waterways and flood damage costing the country $9 billion annually, parking lots represent an obvious opportunity for implementing green stormwater infrastructure. 

By my very rough math, parking lots are responsible for tens of billions of gallons of stormwater runoff annually. That represents runoff that not only needs to be treated, but it’s also water that never makes its way back into the ground to recharge groundwater. In drought-plagued regions like the southwest and California, groundwater recharge is one of the most critical water management strategies that can be implemented. 

One easy solution to this problem is to make parking lots surface-permeable. The right permeable pavement technology, when it’s accompanied with good engineering, is a no-brainer approach to stormwater management and groundwater recharge.

Besides the environmental benefits, the economic benefits of permeable pavements are understated. Getting stormwater back into the ground naturally is extremely valuable. Simply put, every gallon of freshwater that doesn’t need to be treated at a downstream wastewater treatment plant or imported from hundreds of miles away, represents real savings for a community.

In a previous post we addressed why we don’t yet see permeable pavement everywhere. At AquiPor, we’re working to change that with a technology that makes permeable paving the norm and not the exception in cities. The parking lot seems like a good place to start this trend.