soil and pollutants, thus cleansing the water entering into a stream, wetland, or lake. These habitats are easily disrupted or removed when a house and associated landscape are inserted into a natural setting. Diversity is essential to a healthy ecosystem because it supports interdependence and is more resistant to disease and stress. Retained natural habitats should be as large as possible and connected to each other within the site or to others in adjoining sites to promote species diversity and the movement of flora and fauna within them (Figure 3—7). Figure 3-5
A vegetation buffer should be located at the edge of all water bodies to filter surface runoff. Although small drainage ways can be relocated, it is nevertheless disruptive and may require unnecessary grading. Likewise, no structural element should be placed in low areas and wetlands, because these are critical wildlife habitats and places where water percolates into the ground to recharge subsurface water. Figure 3-4
All structures and paved areas should be located outside drainage ways. Surface water in all these forms should be protected to maintain is natural flow, reduce erosion, minimize pollution, and protect aquatic life in the water. This is especially desirable where water from driveways, pool areas, fertilized lawn areas, and vegetable gardens drains into a water body. Even the well — intentioned objective of preserving selected habitats or forms of wildlife while removing others can cause environmental harm because of the interdependent aspect of the life in a natural setting. In addition, different habitats should be preserved if the site permits. Open lawn or meadow areas, perennial and annual gardens, woodland edges composed of shrubs and small trees, woodlands, wetlands, and so on should all be present in temperate climates to create diverse environments for a range of living
Figure 3-3
Alternative techniques for minimizing grading on steep sites. Figure 3-6
A diverse range of environments should be created for wildlife habitats. Maintain Wildlife Habitats
Birds, animals, insects, and microorganisms live in a range of habitats from within the ground to tree canopies above. Surface water exists on all sites, if only temporarily. organisms, as in Figure 3—6. Fragmented and isolated habitats should be avoided. During and after a storm, water drains across and through a site seeking low channels and areas to collect. Local and regional environmental regulations should be consulted to determine the depth of the required buffer.
