Sustainable site design begins with the realization that much can be learned from nature. It is important to understand the relationships of natural systems in order to work within these constraints and creating the least amount of environmental impact.

wind

The major advantage of wind in site development is its cooling aspect. For example, trade winds in the tropical environments often come from the northeast to the southeast quadrant, orientation of structures, and outdoor gathering places to take advantage of this cooling wind movement, or "natural" air conditioning.

Wind can also result in heat loss. The following design practices can minimize this effect:

• grouping buildings to avoid long uninterrupted passages and short gaps between buildings;
• joining buildings, particularly housing, to create shelter and reduce the external wall:volume ratio;
• building to a uniform height;
• the use of densely planted shelterbelts, but take care to avoid overshadowing;
• avoiding development in frost pockets or on exposed hillcrests;
• designing large buildings to avoid increasing air speed and turbulence

sun

The layout of a site will have a direct impact on the potential for maximizing both passive and active solar gain in any development. Site orientation for sustainability will take advantage of daylighting, passive heating, and easier sun control. Passive solar gain alone can save up to 10% of heating demand and does not impose significant additional costs or design constraints on a development.

The following principles should be applied:

• roads should run east-west wherever possible to enable the orientation of dwellings to face within an angle 30 degrees of due south;
• consider the impact of trees, other buildings, walls and fences on overshadowing which may result in limited passive solar heating, particularly on north facing slopes;
• maximum use should be made of south facing slopes which will allow closer spacing of buildings and trees while avoiding overshadowing;
• taller buildings should be located to avoid overshadowing neighboring buildings;
• generally all buildings should be spaced to avoid overshadowing;
• car parking areas and garages should be located to the north of buildings;
• consider the use of active solar technologies, such as photovoltaics;

rainfall

Wastewater or excess runoff from developed areas should be channeled and discharged in ways that allow for groundwater recharge instead of soil erosion. Minimizing disturbance to soils and vegetation and keeping development away from natural drainageways protect the environment as well as the structure. Please visit the stormwater section for specific design recommendations.

topography

Slopes do not have to be an insurmountable site constraint if innovative design solutions and sound construction techniques are applied. Topography can potentially provide vertical separation and more privacy for individual structures. Again, protection of native soil and vegetation are critical concerns in high slope areas, and elevated walkways and point footings for structures are appropriate design solutions to this problem.

geology and soils

Designing with geologic features such as rock outcrops can enhance the sense of place. Soil disturbances should be kept to a minimum to avoid erosion and discourage growth of exotic plants. If limited soil disturbance must take place, a continuous cover over disturbed soils with erosion control netting should always be maintained.

aquatic ecosystems

Development near aquatic areas must be based on an extensive understanding of sensitive resources and processes. In most cases, development should be set back from the aquatic zone and protective measures taken to address indirect environmental impacts. Particularly sensitive habitats such as beaches should be identified and protected from any disturbance.

vegetation

Exotic plant materials, while possibly interesting and beautiful, are not amenable to maintaining healthy native ecosystems. Sensitive native plant species need to be identified and protected. Existing vegetation should be maintained to encourage biodiversity and to protect the nutrients held in the biomass of native vegetation. Native planting should be incorporated into all new developments on a 2:1 ratio of native plants removed. Vegetation can enhance privacy, be used to create "natural rooms," and be a primary source of shade. Plants also contribute to the visual integrity or natural fit of a new development in a natural setting.

wildlife

Sensitive habitat areas should always be avoided.

visual character

Natural vistas should be used in design whenever possible. Creating onsite visual intrusions (road cuts, utilities, etc.) should be avoided, and views of offsite intrusions carefully controlled. It is easier to minimize the building footprint initially than it is to heal a visual scar at the end of construction.