The following strategies foster minimal site impact. It is cheaper to ship stone from a local quarry than from one that is miles away in a distant part of the country or world. Further, the use of regional materials benefits the local economy by employing people who live in the area. Regional plant materials or “native plants” are those found growing naturally in the geographic region, which are inherently adapted to local climate, soil, insects, and so on. However large, each region is distinguished by its own particular physical character and environment. What is appropriate in one region is often not suitable in another. These factors should affect the size, location, and orientation of all outdoor spaces and use areas on the residential site. All structures and pavement areas must be detailed with frost in mind in cold regions, whereas there is no need for this in warm climatic regions. In addition to sharing the benefits of other regional materials, indigenous plant materials have the innate ability to survive unattended in the region and are often acclimated to growing in plant associations with other native vegetation. Regional plants might also include vegetation from other locations with similar climate and soil conditions, though care must be taken to ensure that such plants are not invasive or hosts to pests not normally found in the region. Minimal Site Impact
Principle: The residential site design should have minimal impact on the
existing site. Every geographic location has its own unique ecology collectively established by climate, topography, geology, soil, vegetation, and fauna. Use Regional Materials
All materials used in the sustainable landscape should be manufactured, quarried, or found within the region as much as practically possible. In addition, plants should be selected based on temperature ranges (hardiness zones), precipitation amounts, and precipitation cycles. Principle: The residential site should conform to the regional context. First, local materials are visually harmonious with a site because their compositional makeup, color, texture, and so on are all around and part of the material palette that defines the regional character. A second benefit of utilizing regional materials is that they often cost less because transportation expenses are minimized. Ideally, a landscape should be designed to use only as much water as is available from natural precipitation and augmented, if at all, with irrigation in selected areas (also see “Conserve Water” in “Natural Events and Cycles” in this chapter). How materials are joined, are finished, or extend into the ground should similarly be determined by regional climate conditions. These interdependent natural factors along with human-imposed territories such as municipalities, townships, or counties define a region. The regional climate should affect what construction materials and techniques are employed (also see “Use Regional Materials” in this section). On sites that have been drastically changed by a previous homeowner or developer, as is common in many new subdivisions, the challenge is one of saving any remnants of a natural landscape or keeping natural features and elements that were sensitively introduced to the site. Sustainable design recognizes the special qualities of each region and adapts site organization, materials, construction techniques, and overall visual quality to fit them. Employing materials obtained in the region has several advantages. A sustainable design alters the existing site conditions as little as possible by preserving the elements that are present on a site as well as the natural processes and cycles that support them.