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Green BuildingGuidelines for Design
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Landscape : Introduction
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Landscape Introduction
Minimize Stormwater Runoff
Water Efficient Irrigation
Use of Water Features
Shading Buildings
Enhance Building Ventilation
Environmental Landscaping
Urban Agriculture & Gardens
Shelter & Habitat for Wildlife
Recycled Materials |
Lawns, ornamental shrubs and trees, often poorly adapted to difficult
urban conditions, have for many years dominated urban landscape design.
To survive, these landscapes require high levels of maintenance,
irrigation, fertilizers, herbicides and pesticides. These not only
increase the cost of ownership, but pollute stormwater runoff and
provide little or no habitat for local wildlife.
Ecologically
based landscape design can change this pattern. It considers a region’s
water flows, climate, open spaces, native vegetation, wildlife and
existing urban development. Understanding the ecology of the region
helps when working with the needs of a specific site design, including
its solar access, wind patterns, topography, rainfall and drainage
patterns, the preservation of existing vegetation and unique features
of the site. |
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In recent years the City of Santa Monica has promoted a more environmentally responsive approach to landscape design, particularly in water conservation. Through the City requirement to use drought-resistant plants, restrict the amount of lawn and the use of efficient irrigation systems, water consumption has dropped significantly.
The Required Practices focus on landscape design that conserves water and improves water quality. Outdoor water use accounts for approximately 35% of overall water consumption in Greater Los Angeles, of which half is used to irrigate gardens and landscaping. Planting drought-tolerant vegetation, minimizing lawn areas and using drip irrigation can reduce water use in the garden by 50% to 70% and overall water consumption by 20% to 25%. By managing stormwater runoff through on-site surface water retention and reducing the area of impermeable paving, fewer pollutants enter Santa Monica Bay.
The Recommended Practices address a broader range of environmental benefits gained through landscape design. These include improving the microclimate around buildings to reduce cooling energy consumption and improve occupant comfort, reducing glare, enhancing the appeal of exterior spaces, providing habitat for urban wildlife and creating opportunities for local food production.
Controlling Solar Gain and Improving Ventilation
Controlling solar gain in a building through planting on south, southwest and southeast sides of buildings is a very effective way to reduce cooling loads. In Santa Monica, where southwest-oriented building facades have the greatest solar heat gain, planting shade trees regulates heat gain and reduces air-conditioning needs. Trees and other vegetation can also shade paved areas and provide a canopy for pedestrians.
In addition to controlling solar gain, landscaping and landscape structures can enhance a building’s natural ventilation and cooling by influencing wind flow. This requires the landscape design to respond to prevailing wind patterns and local wind flow variations, and strategically locating trees, hedges and shrubs to direct winds toward ventilation inlets and create low-pressure areas at outlets. Dissipating turbulent, higher velocity winds in circulation areas around buildings can also be achieved by placing a multi-layered planting of large trees and shrubs with dense foliage at the base and corners of buildings.
Air Quality and Wildlife Habitat
Ecologically based landscape design can improve local air quality by absorbing carbon dioxide, producing oxygen and filtering particulates. Landscaped parks and streets provide a “green lung” for the community. Building roofs and balconies can be deliberately designed to accommodate vegetation. Conventional roofs degrade air quality by replacing a site’s original vegetative cover with an impervious surface that absorbs solar energy and contributes to the urban heat island effect. Planted roofs provide a living surface that cools and insulates the building, improves air quality and protects roof membranes from ultraviolet breakdown.
Landscape design can create important habitat for resident and migratory wildlife by providing food and shelter. Through mulching and composting green matter, ecologically-based landscaping can maintain and improve soil fertility, retain soil moisture, stimulate soil-based microbial activity and maintain the cycle of nutrients in the soil. In addition, the use of native and other ecologically appropriate plants reduces water consumption, maintenance requirements, and the use of pesticides and herbicides, and increases the area's suitability for wildlife.
Health Benefits of Ecological Landscaping
Finally, environmentally based landscape design practices can have direct financial and human health benefits. Capital and annual utility costs and regular maintenance requirements can be reduced, resulting in lower overall operating costs. Incorporating areas to grow food within developments encourages local food production and reduces monthly food expenses. It can provide occupants with a secure source of organically grown, fresh produce. Opportunities to garden provide personal health benefits that can improve the quality of life, particularly for older people with leisure time to enjoy gardening. |
Last updated: Tuesday, 02/09/2010
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