The Development Footprint - Treading Lightly on the Land
The term footprint makes a good metaphor for the human imprint on the natural world. Since there are few places on the planet that remain untouched by man, our collective footprint on the earth is pretty massive. The actions of each individual also have a footprint, or influence on the natural world. People are not really outside of nature, and our footprints, or imprints, on the natural world are not always negative. Typically, the more our actions are in harmony with natural processes, the more conducive they are to environmental health and well-being. Living sustainably implies treading lightly on the land and minimizing adverse effects of our activities on nature.
The development footprint is the total land area that is affected by development activities, and includes buildings, structures, hardscape, utilities, roads and parking areas, as well as any areas that are driven over, trampled or cleared of natural vegetation and topsoil. Though the total environmental footprint of a development often extends well beyond the property lines, to include off site impacts such as dust & noise pollution, alteration of drainage patterns, migration of pollutants, fragmentation of natural habitats, as well as impacts from material life cycles, and transport, this post focuses on the on-site impacts that can be addressed at the site specific level.
In terms of environmental health, it is important to keep the development footprint as small as possible, in terms of both area and degree of impact. By minimizing the total amount of space needed for a project, we can conserve more of the site for natural areas. The conventional approach involves clearing, grubbing and bulldozing the whole site up to the property lines. This may be necessary, if the whole site needs to be used for buildings and parking, but usually a portion of the site is dedicated to landscape. Construction activities destroy, not only the existing vegetation, but also compact the soil, killing micro-organisms and causing it to lose much of its natural structure, water holding and carbon storage capacity, and making it less suitable for plant growth. Reducing the building footprint and leaving existing vegetation intact, will also reduce the area that will need “landscaping”, which can significantly reduce a project’s construction and operating costs.
One of the most significant actions we can take in terms of protecting native plants and animals is to set aside high-value natural areas for conservation. If a site inventory is done early in the design process to identifying the critical natural resources on a site, the proposed development footprint can be adjusted so that these areas are protected. Often the development foot print can be limited to the smallest area needed to accommodate the proposed buildings roads, parking, walks, and site features, along with a small buffer to for maneuvering and earth grading. Construction and staging activities should be confined to narrowly defined corridors to minimize disturbance to natural features. After construction activities are substantially completed, adjacent areas with disturbed soils can be improved, stabilized and landscaped with native and non-invasive plant species, to transition back to the natural areas. Footprint constraints can be a small inconvenience for construction crews, but a reduced footprint will result in reduced construction and operating costs, due to less area being, cleared, grubbed, graded, landscaped and irrigated.
The area designated as the development footprint should be clearly marked on the site with protective fencing. Penalty/Bonus clauses can be included in contract documents to help insure workers stay within the designated work area. Operation of equipment, driving, walking and materials storage should not be allowed in protected areas. Vehicular and pedestrian circulation routes, storage and staging areas can be typically be located in proposed roadways and parking areas to minimize site disturbance.
The development footprint of a community can be reduced through planning that directs new development to infill areas and previously developed lots. Zoning for high density population centers, combined with conservation of the high value natural and agricultural areas, helps to minimize the community footprint and conserve natural resources. Planning so that living, working, shopping and recreation areas are all in close proximity can greatly reduce the number and distance of automobile trips. This will in turn reduce the land area needed for parking and roads. A network of open space can be incorporated into populated areas to enhance public welfare and quality of life, reducing pollution, improving storm water infiltration and reducing soil erosion, providing recreation areas, creating wildlife corridors, and preserving critical habitats, prime agricultural land and scenic resources.