Innovative Stormwater Management POROUS ASPHALT PAVEMENT with Subsurface Recharge Bed Porous Asphalt • Conserves water • Reduces runoff • Promotes infiltration • Cleans stormwater • Replenishes aquifers • Protects streams • Better Water Quality Uncompacted Subgrade - Keeps permeability high to • Allows for better use allow as much infiltration as possible. of land Non-Woven Geotextile - Protects stone recharge bed above from contamination and allows water to flow through to the soil. Stone Recharge Bed - Heart of system. Large, single size, crushed stone with 40% voids stores storm water for infiltration. Choker Coarse - Single size crushed aggregate (1/2-inch) stabilizes surface for paving. Open-Graded Asphalt Pavement - An open-graded asphalt mix that is porous, allowing storm water to flow through surface into stone recharge bed. Unpaved Stone Edge - A backup system in case the pavement surface should ever become sealed. Stormwater can flow off pavement surface to stone edge and into stone recharge bed. Other methods may be used. Additional information can be found at these resources: P.O. Box 668, www.hotmix.org (Porous asphalt design guide) Brainerd, MN 56401 www.thcahill.com (Leading environmental consultants with 218-829-1768 porous asphalt) www.andersonbrothers.com Better Water Quality With Porous Construction and performance Economics pavement have been used in Asphalt California since the 1950s. Salmon The stone bed, often eighteen to thirty-six inches in depth, Porous pavement is a sound hatcheries and fish rearing ponds provides a tremendous sub-base for the pavement. As a choice on economics alone. in the Pacific Northwest use asphalt In 2005 Anderson Brothers was proud to have been the result, porous asphalt pavements tend not to exhibit crack- Because porous pavement is liners. first contractor in the state in install porous pavements. ing and pothole formation problems. The surface wears designed to “fit into” the topogra- Now we’ve been honored to have the largest and the most well. Under the stone bed is a geotextile, which keeps fine phy of a site, there is generally Variations on the theme installations - paving the way for this environmental initia- tive in central Minnesota. less earthwork. The underlying stone bed is usually more expen- Porous asphalt can be used suc- Porous asphalt offers a powerful tool in the toolbox for sive than a conventional com- cessfully in parking lots, walkways, storm-water management. pacted sub-base, but eliminating and playgrounds. Several current the detention basin and other suburban projects are exploring its In the natu- components of stormwater manage- Cooler cities use in subdivision roads. A few porous ral environ- ment systems offsets this cost differ- highways and city streets have been ment, rain- Porous asphalt pavements have been ence. On projects where unit costs constructed, both in the U.S. and in fall sinks into shown to mitigate the urban heat have been compared, the porous Europe, and have performed well. The soil, filters island effect. Open-graded asphalt pavement has been the less expensive open-graded asphalt surface used for through it, roads and highways—which use the option. Porous pavements are there- porous pavements has been used and eventu- same surface material as porous park- fore attractive on both environmental extensively to surface high-volume ally finds its ing lots—have been shown to lower particles from moving into the stone bed from below and and economic grounds. An installa- highways that carry heavy trucks. Its way to nighttime surface temperatures as filling in the spaces. The recharge beds must be built cor- tion at the University of North Carolina benefits include noise reduction, a streams, compared to impervious pavements. In rectly and over permeable soils in order to function prop- in Chapel Hill included parking lots decrease in splash and spray kicked p o n d s , at least one city, the hottest heat erly. Porous asphalt has been proven to last for decades, where some sections were constructed up by vehicles in heavy downpours, lakes, and signature is at the airport, with its even in extreme climates, and even in areas with many from porous asphalt and others used and mitigation of the urban heat island underground aquifers. The built environment, by way of thick, dense, impervious runways. freeze-thaw cycles. The underlying stone bed can also porous concrete. The cost differential effect. contrast, seals the surface. Rainwater and snowmelt provide stormwater management for adjacent impervious Comparisons to other asphalt pave- become runoff, which may contribute to flooding. was approximately 4:1 – that is, the areas such as roofs and roads. To achieve this, stormwa- ments the surface of a porous asphalt Contaminants are washed from surfaces directly into porous concrete pavement cost four If you have an interest or questions ter is conveyed directly into the stone bed, where perforat- pavement wears well. While slightly waterways without undergoing the filtration that nature times as much as the porous asphalt regarding porous pavements please ed pipes distribute the water evenly. coarser than some pavements, it is intended. For these reasons, managing stormwater is a pavement. contact us at Anderson Brothers. We’d attractive and acceptable. Most people significant issue in land use planning and development. love an opportunity to show you how The long-term maintenance of porous asphalt is not diffi- driving or walking on the pavement Stormwater management tools can serve to mitigate the Impact on groundwater we can help your project. cult. Never apply sealant or sand to surfaces that would will not notice (or believe) that it is impact of the built environment on natural hydrology. clog the pores in the pavement. For the same reasons porous. Like all asphalt pave- Unfortunately, however, they also can lead to unsound Asphalt pavements are compatible adjacent landscaping should be designed to ensure that ments, porous pavements meet solutions such as cutting down stands of trees in order to with clean water. Studies show that mud couldn’t be washed into the parking lot surface. the requirements of the build detention ponds. Porous asphalt pavements allow for asphalt pavements and stockpiles of land development plans that are more thoughtful, harmo- Americans with Disabilities Act reclaimed asphalt pavement do not nious with natural processes, and sustainable. They con- (ADA). leach. Contaminants on the surface of serve water, reduce runoff, promote infiltration, which pavements tend to become part of cleanses stormwater, replenish aquifers, and protect Environmental applications runoff, but with a porous pavement, streams. A typical porous pavement has an open graded they are washed into the stone bed. surface over an underlying stone recharge bed. The water Asphalt pavements have been From there they flow down into the drains through the porous asphalt and into the stone bed, used for many years to enhance soil, where beneficial bacteria and then, slowly, infiltrates into the soil. If contaminants were water quality. At landfills, on the surface at the time of the rainfall, they are swept other natural processes cleanse them. asphalt liners and caps keep along with the rainwater through the porous asphalt. From Data are limited, but indicate a very Water is shown standing on regular pavement in the contaminants from leaking into there they infiltrate into the recharge bed and sub-base high removal rate for total suspended lower right corner. While the water is percolating groundwater. Drinking water through the porous asphalt as it leaves the garden which filters out the non-point source pollutants through an solids, metals, and oil and grease. reservoirs lined with asphalt hose. array of physical, chemical and biological mechanisms.
Pages to are hidden for
"Innovative Stormwater Management POROUS ASPHALT PAVEMENT"Please download to view full document