ASLA 2013 Professional Residential Design Honor Award. Catalina Foothills / D. A. Horchner / Design Workshop, Inc.
Due to reoccurring drought conditions worldwide, using potable (drinkable) water for landscapes is increasingly unviable. Homeowners often wastefully irrigate their lawns with water than should be reserved for human consumption. According to the Sustainable Sites Initiative, irrigation of unsustainable residential landscapes accounts for more than a third of residential water use—more than seven billion gallons of potable water per day in the U.S.
Sustainable residential landscape architecture—if part of a broader "integrated site design," a comprehensive approach to sustainable building and site design—can dramatically reduce water usage over the long term while creating a healthy residential environment.
Integrated site design is a framework for increasing the quality of the built environment, and involves maximizing existing natural systems to minimize water use. These types of designs leverage the many benefits of natural systems, thereby significantly cutting down the need for centrally distributed water. Decreased water usage also means homes are more resilient to shifts in the availability of water and climate change.
Homeowners can promote the infiltration, storing and recycling of water, and limit the use of valuable potable water for landscapes. Bioswales / bioretention ponds, rainwater gardens, and local sustainable water recycling and drip irrigation systems can all be used to efficiently conserve water. Homeowners can use these systems to recycle and reuse greywater (and even blackwater) for landscape maintenance, car washing, and toilet flushing.
Homes that include natural stormwater management technologies, such as a bioswales or bio-retention ponds, which infiltrate and remove pollutants, not only better manage stormwater runoff, but also reduce the massive energy costs associated with running complex stormwater management systems. Water utilities' centralized stormwater management infrastructure are heavy users of energy in local areas.
Local governments are also partnering with non-profit organizations to increase public awareness about using sustainable residential design practices for improving water efficiency.
American Water Works Association
Clean Water Network
Renewable Natural Resources Foundation
Sustainable Sites Initiative
Water Infrastructure Network
Water Resources, Natural Resources Defense Council
"Cities of the Future: Towards Integrated Sustainable Water and Landscape Management," Vladimir Novotny and Paul Brown (editors), IWA Publishing, 2007
"Water Consciousness," Tara Lohan, Alternet books, 2008
"When the Rivers Run Dry: Water: The Defining Crisis of the 21st Century," Beacon Press, 2007
"Handook of Water Use and Conservation: Homes, Landscapes, Industries, Businesses, Farm," Amy Vickers, WaterPlow Press, 2001
Cases in Water Conservation, U.S. Environmental Protection Agency
Landscape Watering by the Numbers, City of Phoenix, Arizona
Sustainable Infrastructure for Water & Wastewater, U.S. Environmental Protection Agency
Water Conservation, City of Vancouver
Water Efficiency, Energy Efficiency & Renewable Energy, U.S. Department of Energy
Water Resources Plan, City of Phoenix, Arizona
WaterSense, U.S. Environmental Protection Agency
Ways to Save Water, New York Department of Environmental Protection
Victoria Garden Mews
Santa Barbara, CA
Woody Creek Garden, Pitkin County, Colorado
Design Workshop, Inc., Aspen, Colorado
Other Resource Guides in this Series:
Sustainable Design Resource Guides:
Residential Bioswales / Bioretention Ponds
Bioswale and bioretention ponds use plants and soils to infiltrate and treat stormwater runoff. These systems can also dramatically reduce pollutants and contaminants in an effort to increase water quality. Bioswales, which are wet or dry swales made out of grass, rocks, and other types of vegetation, must be sloped to move water through the system in an efficient manner. Bioretention ponds, depressed vegetated area areas that capture and store stormwater runoff, can work in combination with bioswales.
Under federal and state requirements, local governments must implement stormwater management plans and systems. Centralized stormwater management systems are energy-intensive and costly to create and maintain. Local communities can instead invest in decentralized stormwater management systems by expanding the use of bioswales and bioretention ponds in residential areas. Bioswales and bioretention ponds can dramatically reduce water flowing into centralized stormwater management systems, and therefore, limit the energy consumed by centralized water utilities pumping and recycling water.
Local governments work with planners and design professionals to develop more sustainable, decentralized stormwater management systems featuring bioswales and bioretention ponds. Homeowner associations and local community groups play a part in maintaining these systems. Local governments can offer homeowners incentives to create decentralized stormwater management systems on their properties.
Bioswale/bioretention pond benefits include:
- Reduced runoff: In a typical road, a 4-meter swale can reduce approximately 25 percent of total rainfall runoff.
- Reduced pollutants: Bioswales/bioretention ponds remove pollutants by filtering stormwater runoff through natural vegetation and soil-based systems.
- Recharged groundwater: Instead of releasing stormwater into the drainage system, stormwater can be filtered and may provide some groundwater recharge.
- Improved energy efficiency: Sustainable, decentralized stormwater management systems may be more cost effective than centralized stormwater systems. At the minimum, these natural technologies reduce pressure on existing systems and the maintenance costs associated with centralized stormwater management systems.
Sources: Bioswales, Capital Regional District, Vancouver
Residential Rain Gardens
The Low Impact Development Center
Bioswales, Natural Resources Conservation Service, USDA
Certified Projects, Sustainable Sites Initiative (SITES)
Stormwater Solutions Handbook, City of Portland
Urban Design Tools / Low Impact Development
Vegetated Swales Fact Sheet, Charles River Watershed Association
Model Storm Water-based Landscape Code, Department of Environmental Quality, State of Louisiana
San Francisco Better Streets Plan, San Francisco, California
Stormwater Program, Environmental Protection Agency
High Point, West Seattle, Washington
NE Siskiyou Green Street, Portland, Oregon
Kevin Robert Perry, ASLA
SEA Street, Seattle, Washington
SW 12th Avenue Green Street Project, Portland, Oregon
City of Portland, Department of Transportation
Rain gardens are a depressed vegetated area that use rainfall and stormwater runoff as irrigation. Rain gardens capture and hold water, usually through the use of native plants. By using highly porous plant materials, rainfall and stormwater runoff can drain more effectively. Rain gardens allow approximately 30 percent of runoff to be filtered into the ground. A properly designed rain garden can filter one inch of rainfall in four hours
Instead of extending conventional water infrastructure at great cost, rain gardens can be used to collect rainwater, store it at the residential level, and reduce residential stormwater runoff. Like bioswales or bioretention ponds, the main role of rain gardens is to reduce water flow and limit water volume.
Sources: Rain gardens fact sheet, Rutgers University
Bluegrass Rain Garden Alliance
Rain Garden Initiative
"The Rain Garden Planner: Seven Steps to Conserving and Making Water in the Garden," Terry Wallace, Schiffer Publishing, 2008
"Rain Gardens: Managing Water Sustainably in the Garden and Designed Landscape," Nigel Dunnett & Andy Clayden, Timber Press, 2007
Residential Rain Water Harvesting
10,000 Rain Gardens
Central Ohio Rain Garden Initiative
Rain Garden Design Templates, Low Impact Development Center
Rain Garden Manual for Homeowners, Geauga Soil and Water Conservation District
Rain Gardens, Water Resources Program, Rutgers New Jersey Agricultural Experiment Station
Toledo-Lucas County Rain Garden Initiative
Build a Rain Garden, City of Gresham, Oregon
Rain Gardens, City of Bowling Green, Ohio
Rain Gardens, County of Washtenaw, Michigan
Rain Garden Grant Program, Milwaukee Metropolitan Sewage District
Rain Garden Grants, City of Savage, Minnesota
Residential Rain Garden Grants, Clermont County, Ohio
Forbes House Rain Garden, City of Kirkland, Washington
"Greening" Stormwater with Rain Gardens: Virgin Islands Rain Garden Demonstration Project, Estate Lower Love, St. Croix, Virgin Islands, National Resources Conservation Service, USDA
Private Residential Garden, Minneapolis, Minnesota
Oslund.and.assoc., Minneapolis, Minnesota
Rainwater harvesting is a system that collects, diverts, and stores rain in a catchment tank. Rainwater can be successfully used for landscape irrigation because rainwater is collected directly from the sky, and avoids many pollutants water collects by flowing through streets. The harvested rainwater can also be used for car washing and toilet flushing.
Rainwater harvesting is an efficient sustainable water management technique common before public utility departments centralized and then re-distributed water.
Rainwater harvesting benefits include:
- Reduced consumption of distributed potable water: 30 to 50 percent of potable water is currently used for landscape irrigation.
- Reduced water bills and demand on existing water supply.
- More efficient use of rainwater resources.
Sources: Rainwater Harvesting, Texas A & M University
American Rainwater Catchment Systems Association
Rainwater Harvesting, Centre for Science and Environment
"Design for Water: Rainwater Harvesting, Stormwater Catchment, and Alternate Water Reuse," Heather Kinkade-Levario, New Society Publishers, 2007
"Rainwater Harvesting for Drylands and Beyond: Water-Harvesting Earthworks," Brad Lancaster, Rainsource Press, 2007
Rain Barrels and Cisterns, Urban Design Tools, Low Impact Development
Rainwater Harvesting, Texas A & M University
Toronto Homeowner’s Guide to Rainfall, RiverSides
Residential Water Recycling
How to Manage Stormwater – Rain Barrels, Environmental Services, City of Portland
Los Angeles Rainwater Harvesting Program, City of Los Angeles, California
Managing Wet Weather with Green Infrastructure: Municipal Handbook – Rainwater Harvesting Policies, Chris Kloss, Low Impact Development Center for U.S. Environmental Protection Agency
Oregon Smart Guide – Rainwater Harvesting, Department of Consumer & Building Services, State of Oregon
Portland Residential Rainwater Harvesting Code Guide, Bureau of Development Services, City of Portland
Rainwater Harvesting, Bureau of Planning and Sustainability, City of Portland
Recycled water is highly treated domestic wastewater that can be used for landscapes. There are multiple grades of wastewater -- Greywater is domestic wastewater from kitchen sinks, dishwashers, and washing machines. Greywater may include household cleaning products and food particles. Blackwater refers to water used in toilets -- water that contains human excrement. In total, 50 to 80 percent of water used in homes is recyclable. Greywater (and even blackwater) can be diverted and treated through a filter system and then further used to irrigate landscapes.
Depending on the extent of treatment, recycled water can be cleaner and safer to use than tap water. This practice has become more widespread in California and other arid states. Each state has a set of specific regulations on the use of recycled water use, and some states require permits. Using recycled water can significantly reduce residential water waste.
Source: Household Waste Water Recycling Systems, Green Living
Australian Water Association
National Onsite Wastewater Recycling Association
Water Reuse Association
"Water Recycling 2030: Recommendations of California’s Recycled Water Task Force," Department of Water Resources / California Recycled Water Task Force
"The New Create an Oasis with Greywater: Choosing, Building and Using Greywater Systems – Includes Branched Drains," Art Ludwig, Oasis Design, 2006
"Guidelines for Water Reuse," U.S. Environmental Protection Agency, 2004
Grey Water Policy Center
Household Waste Water Recycling Systems, Green Living
Recycled Water in Australia
Green Plumbers: Best Practice Guidelines for Installation of Household Stormwater and Greywater Recycling Systems, National Water Commission, Australian Government
Greywater and Wastewater, Australian Government
Greywater and Wastewater, Deparment of the Environment, Water, Heritage and the Arts, Australian Government
Groundwater Replenishing System, Orange County Water District, California
National Rainwater and Greywater Initiative, Department of Environment, Water, Heritage and the Arts, Australian Government
Recycled Water Codes and Ordinances, Marina County Water District
Recycled Water Policy, California State Water Resources Control Board, California Environmental Protection Agency
Recycled Water Program, City of San Diego, California
Recycled Water Use in the Landscape, Government of Canada
Waste Water Systems, Department of Planning and Development, City of Berkeley, California
Water Recycling and Reuse: The Environmental Benefits, U.S. Environmental Protection Agency
Virginia Polytechnic Institute and State University
Residential drip Irrigation
Drip irrigation systems conserve water by providing water through slow application directly at plants’ root zones, keeping the plant root zone at optimum moisture level. Residential drip irrigation systems reduce over-watering, evaporation, runoff, and deep percolation of water.
Drip irrigation is a cost-efficient means of improving water efficiency. Unlike other irrigation systems, drip irrigation is adaptable to any landscape and requires minimal maintenance. This system is predominantly used in agriculture and nurseries, but can also be used in residential landscapes for vegetable and perennial gardens.
"Drip Irrigation for Every Landscape and All Climates," Robert Kourik, Metamorphic Press, 2009
"Basic Landscape Irrigation," Neil W. Johnson, Vignettes Publishing, 2009
How Irrigation Works, How Stuff Works
Draft Water Efficient Landscape Ordinance, City of Paso Robles, California
WaterSense-based Irrigation Controllers, Environmental Protection Agency
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