Professional Practice
Using Low-Impact Materials: Permeable Surfaces
The site's impervious surfaces where reduced by almost 70% with gravel paths and drought-tolerant planting. Ë¿¹ÏÊÓƵ 2014 Professional Residential Design Honor Award. Vineyard retreat, Napa Valley, California / Scott Lewis Landscape Architecture. Rainfall picks up contaminants from impervious surfaces such as asphalt and concrete streets, driveways, and other pathways, which further contribute to water pollution. In comparison, increasing a site¡¯s permeable surfaces allows for natural filtration and reduces the costs associated with adding stormwater management systems.
Permeable surfaces increase evapotranspiration, filtration and infiltration, and mitigate elevated water temperatures caused by contact with impervious surfaces. Permeable surfaces mitigate and control stormwater runoff by allowing water to pass through into the underlying soils. This kind of natural filtration process is the most effective way of eliminating water contaminants and pollutants.
Soil on residential properties can be degraded and compacted after years of development. Often times, thin layers of turf are rolled out over degraded soil, leaving the grass roots with no soil to grown into. The lawn will need a lot of fertilizer and water to survive, and the thin veneer of grass does not help capture any stormwater. Homeowners can use soil remediation techniques like subsoiling and adding soil amendments to improve water absorption, promote plant root establishment, and increase surface permeability.
Landscape architects can design residential properties to increase a site¡¯s permeability with additional vegetation and soils and limit hardscapes by using porous materials like gravel and mulch.
More Resources
Permeable Pavers
Organizations
Resources
, RecycleWorks, County of San Mateo
, The DIRT, American Society of Landscape Architects
, The DIRT, American Society of Landscape Architects
¡°,¡± Timothy Beatley, Island Press, 2016
, Paths for All, Scottish Government
, The Dirt, American Society of Landscape Architects
, The Dirt, American Society of Landscape Architects
Government Resources
, City of Chicago
, City of Chicago
, Florida Field Guide to Low Impact Development, University of Florida
, Department of Energy & Environment, D.C.
, Los Angeles Trust for Public Land
Projects
Vineyard Retreat, Napa Valley, California
Scott Lewis Landscape Architecture
, Cambridge, Massachusetts
Julie Moir Messervy Design Studio
The Crack Garden, San Francisco, California
CMG Landscape Architecture
, Paris, France
Espace Libre
Permeable Pavers
strongly encourages permeable over impervious surfaces. Where hardscapes are needed permeable pavers, or pavement with high porosity, can be used to help reduce stormwater runoff and water infiltration into the ground. Permeable pavers can also trap pollutants that would otherwise enter local water sheds. Permeable paving can allow up to 80 percent of annual rainfall to infiltrate the underlying soil. Residential driveways and walkways can incorporate permeable materials while still maintaining a high-level of aesthetic quality. Often, these materials are also more reflective, which can help decrease the heat island effect.
Source:, Green Building Alliance; , Metropolitan Area Planning Council
Organizations
Resources
, Interpave
, Green Building Alliance
, Landscaping Network
Research
¡°,¡± Permeable Pavements Task Committee, LEED AP Bethany Eisenberg, P.E. Kelly Collins Lindow, David R. Smith, American Society of Civil Engineers, 2015
"," Bruce K. Ferguson. CRC, 2005
Government Resources
, Minnesota Stormwater Manual
, City of Philadelphia
, Permeable Pavement, Environmental Protection Agency
, Environmental Services, City of Portland
Projects
Drs. Julian and Raye Richardson Apartments, San Francisco
Andrea Cochran Landscape Architecture