Stormwater runoff from the built environment, often mixed with contaminants, has a damaging effect on local and downstream ecosystems. Porous paving products and vegetated roofing systems result in less rainwater runoff and thereby reduce surface water pollution. Stormwater treatment systems reduce pollutant levels in any water that is released. Again, quantifiable benefit and a strong track record are important determinants here of “green.”
Bio-Aquifer Storm System
The Bio-Aquifer Storm System (BASS) from Advanced Pavement Technology is an engineered permeable paving system which provides post-construction runoff rates that are the same or better than preconstruction, without the use of detention ponds. The system includes subsurface drainage/detention layers of rocks and aggregate to a minimum depth of 18”, topped with concrete porous pavers. The system permits exceptionally heavy vehicle traffic and is not affected by extreme thermal conditions.
Porous paving seeks to combine the load-carrying capacity we expect of paved areas with the rainwater-infiltration qualities of natural landscaping.
Porous unit pavers made from concrete are of two main types: a grid of openings that can be planted with grass or filled with gravel, and solid unit pavers. The solid pavers are made of concrete with the “fines” left out so that rainwater can be absorbed more readily.
All porous paving systems must be installed over a carefully engineered subsurface that acts as a reservoir for stormwater. This allows pollutants to break down slowly beneath the paved area instead of contaminating surface water. In addition, solid concrete unit pavers also need to have drainage voids along the installed edges.
In addition to managing stormwater, porous paving systems planted with grass also minimize contributions to the urban heat-island effect while providing visually appealing outdoor space.
When possible, look for recycled content and less portland cement.
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