Sustainable land development: is sustainable development a contradiction in terms? Alice Dodson and David Tuch explain how we can develop land in harmony with natural processes.

The intention behind sustainable development is to create a balanced living environment for humans, one that can be maintained in harmony with our planetary environment and nature's life supporting systems. Depending on geographical location and social and environmental circumstances, the application could be very different from place to place. Large crowded cities or the countryside, newly developed areas or historical places, underdeveloped countries versus high-tech societies each carry their own unique set of issues to be resolved.

A high-speed, high-tech, consumer-oriented society creates over-consumption of natural resources and energy, and pollution in the air, in water systems, and on land. Not only are human life and relationships affected by all this, but also our natural environment. In the mountains of Western North Carolina we greatly value the beauty of the land, the cleanliness of water and air and a sense of community is important as well. To create a sustainable development in our region, we need to consider planning low impact land use to preserve natural beauty. Thought must be given to the following issues:

* carefully selecting building sites in order to preserve natural features, habitats

* applying sustainable landscape design principles

* if possible, incorporating the use of alternative non-polluting energy sources, like solar, wind or hydro, when feasible

* using natural, non-toxic building materials and appropriate construction methods

* recycling and reusing

* plans for creating a sense of neighborhood or community

PLANNING AND ARCHITECTURE

With little effort, one can create a healthier living environment by carefully selecting non-toxic finishes, or by using sustainable building materials. With proper design and orientation of the sun considered, a "passive solar design" can be created, which conserves energy by utilizing the solar heat. Solar energy also can be used for hot water-based heating and for domestic hot water as well as creating electricity. There is tax credit for using solar. If you are thinking about the cost consequences of these ideas, some would cost more, and some only require extra attention. One can also consider exchanging the quantity of space for quality, by building smaller but better quality spaces. [For more on passive solar construction, see the article on page 8 of this issue. For more on active solar and tax credits, see page 6.]

The experience of living in addition to the quality of a building can be enhanced greatly by the conceptual design of the housing development as a whole. In most common circumstances, a large tract of land is subdivided, cut up into smaller parcels, and each lot is developed independently. As an alternative, there are several successful examples of Traditional Neighborhood Developments (TNDs). TNDs try to recreate a sense of community through their planned use of the land in some or all of the following ways:

* concentrating or clustering homes on some part of the land, leaving large green areas undisturbed, and creating smaller pocket parks and playgrounds for common use.

* developing streets and walking trails

* planning for all age groups and for various income groups

* planning for mixed use so there could be community and/or recreational buildings as well as live-work arrangement, including stores or small restaurants, etc.

* including sustainable landscaping with possibilities for gardening, etc.

By designing a development with these ideas, there is a better chance to create sustainable land use and preserve some of the natural features of the land. At the same time, spaces and opportunities for people to interact with each other are created, breaking down the barriers of isolation, providing a safer and more comforting community.

LANDSCAPING AND LAND USE

When addressing sustainable residential development from a landscape perspective, it is important to address two key issues. First, respond to the ecology of the landscape. Second, create environmentally sensitive design solutions. These two key issues can be broken into two basic phases: the site analysis phase and the site design phase. The site analysis phase examines the landscape in order to identify areas most suitable for development and areas most suitable for conservation and protection. While the site design phase utilizes ecologically sensitive design principles to create a development that uses nature as a model.

SITE ANALYSIS PHASE

Typically a site analysis provides detailed information regarding a site's hydrology, soils, slopes, solar aspect, microclimate, vegetation, wildlife, scenic qualities, and cultural features. This information should be combined with the site's overall landscape ecological patterns.

The pattern and arrangement of trees, water bodies, and other natural features can characterize a landscape. These patterns are defined as landscape ecological elements and include patches, corridors, and the overall matrix.

A landscape patch can be a wetland, a stand of trees, or a plant community. The significance of a patch for protection is dependent on its contribution to the overall landscape. For example, a large landscape patch that provides interior habitat for birds and is located adjacent to a stream provides a safe connection for wildlife to access the stream. This is significant and should be protected. Also, if a patch contains any rare, threatened, or endemic species, it should also be protected. Patches can serve as steppingstones for species movement to larger patches or as a connection to corridors.

A landscape corridor can be a drainage way, creek, or river and is important because it provides connectivity to other landscape ecological elements, serving as a passageway for wildlife and acting as a filter or buffer. The overall dominant character of the landscape can be identified as the matrix. The matrix is the overall arrangement of the patches and corridors in the landscape. The overall matrix can also help identify areas most important for protection. For example, if the overall matrix is dominated by several large patches of white pine and only a single open meadow exists, then it becomes clear that the rarer open meadow is the most significant landscape ecological element. Therefore, it should be protected.

The landscape ecological pattern not only determines a landscape's ability to house a diversity of plant and animal species, but also influences the landscapes ability to function and carry out natural processes. When roads and houses are placed in the landscape, the entire landscape can be significantly changed, impacting animal routes, water flow, erosion of soil, etc. When the landscape ecological patterns are retained, roads and houses are placed in the landscape without negatively impacting natural processes. If the basic features of a site analysis combined with the information revealed by analyzing the landscape ecological patterns are utilized during the planning of the development, then the most suitable locations for conservation and protection can be determined.

SITE DESIGN PHASE

There are many aspects inherent in a good site design. If certain aspects are approached differently from conventional site design, the site's sustainability can be improved. Among these design issues, the following will be addressed: wastewater, stormwater, and landscaping.

Wastewater refers to all the water used by a home, including the water used in bathrooms, in the kitchen, in the laundry etc. A residential community can be designed to utilize alternative solutions to wastewater treatment. Traditionally, wastewater is piped to a treatment plant where it typically receives chemical treatment prior to being dumped into a stream or river. If a sewer system is not available, septic systems are used. There are alternatives to these traditional approaches, including the use of constructed wetlands, which use plants to create favorable conditions for enzymes, bacteria, protozoa, and fungi that break down and digest organic pollutants.

Gray water is also wastewater, but it does not contain effluent. Gray water is the water used for bathing, dishwashing, or laundry, and it can be reused. For example, gray water can be collected from each house in a residential community and transported to a central location to be used for irrigation of a community's vegetable garden or other plantings. On the smaller scale, if the individual house is plumbed to separate gray water, the water can be reused for watering plants immediately around the house.

Stormwater: Typical development creates impervious surfaces that do not allow rainwater to infiltrate into the ground and collects. The rainwater in a storm drainage system carries the rainwater away from the site. The goal of a sustainable development should be "zero runoff," meaning that all rainwater is collected on-site and either stored for future use or allowed to infiltrate into the ground to replenish the local aquifer. The stored water could be used to irrigate vegetable gardens or landscape plantings, or it could be used during a drought. The use of impervious surfaces (like pavement and concrete) can be minimized and replaced with pervious surfaces (like stone and gravel) whenever possible.

Landscaping: Traditionally, landscape plantings in residential development have been used purely for aesthetic purposes to mark an entrance, define a space, or to screen an unpleasant view. The lawn and introduced plants from other countries have been the major landscape elements used in design. However, sustainable design uses new plantings not only for aesthetic purposes but also to produce food, help conserve a building's energy needs, and create additional wildlife habitat.

A sustainable landscape contains native plants, which are well adapted to the local climate and require less maintenance and watering once established. Lawns require supplemental watering and fertilization to be well maintained, so their use should be limited. There are many native plants that can provide food for wildlife and people as well. Also, there are many nonnative plants that could be beneficial for landscaping purposes and provide food for the community. Orchards, vineyards, herb gardens, and vegetable gardens can all be part of a community's sustainability and self-sufficiency. Site design that incorporates ecologically sensitive design principles including such design elements as using native plants, collecting and reusing rainwater, and cleansing wastewater through biological processes can significantly contribute to the site's ability to be sustainable.

Alice Dodson is an Architect in Asheville, NC, specializing in environmentally conscious residential design. For information, call 828-645-9326 or email [e-mail]

David Tuch is a Landscape & Environmental Designer for Equinox Environmental, an Asheville-based Environmental Consulting firm providing conservation subdivision planning and design services. For information, call 828 253-6856 or e-mail [e-mail]