Parking lots and roads are notorious for sheet flow stormwater runoff. The problem is twofold, first stormwater is diverted from infiltrating the earth in the groundwater as God intended so as to recharge underground aquifer. And second, as it runs off roads and parking lots it collects contaminants and byproducts of vehicular traffic such as nutrients, trace metals, oil and grease, all of which can include harmful elements such as nitrates and orthophosphates. These pollutants concentrate in storm drains and eventually make their way into bodies of water such as our Chesapeake Bay. Once there, the nitrates & orhthophosphates become food sources for algal blooms which are the first step in the eutrophication.
So what is eutrophication? H.W. Art, defined it as “The process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates. These typically promote excessive growth of algae. As the algae die and decompose, high levels of organic matter and the decomposing organisms deplete the water of available oxygen, causing the death of other organisms, such as fish. Eutrophication is a natural, slow-aging process for a water body, but human activity greatly speeds up the process.”
To alleviate this problem, the EPA & the Clean Water Act now require states to adopt total maximum daily load (TMDL) limits as the basis of their water quality improvement. So in one effort to reduce eutrophication among other things, many Architects and Municipalities are choosing to pave sidewalks, trails and parking spaces with Flexi-Pave. Passive Treatment Technologies (PTT), such as Flexi-Pave, provide a cost effective solution for the removal of nutrients from storm water, while saving energy, to reduce nutrient pollution. In fact, a long term water quality study conducted in 2010 by a Civil Engineering & Environmental Firm showed an amazing 83% reduction in nitrates and an 88% reduction in phosphates from contaminated water flowing through Flexi-Pave.
One recent project using Flexi-Pave for this purpose was at Ben Brenman Park in the City of Alexandria, VA where a strip of parallel parking spaces near the baseball fields were installed in 2012. The parking spaces provide 16-20 additional parking spaces and also filter the stormwater runoff from the main roadway. Reviews by city officials and residents have been overwhelmingly positive, so that several additional Flexi-Pave projects are currently in the works for the City of Alexandria.
Ben Brenman Park Parallel Parking Site Plan
