Conservation Subdivision Design

Some new and unique residential subdivisions in the Atlanta metro area are offering what many home buyers would consider as the best of both worlds — modern suburban homes surrounded by woods, wetlands, and other undisturbed green spaces. A recent article in the Atlanta Journal-Constitution discussed the increasing popularity of “conservation subdivision design” (CSD) in several metro Atlanta counties. Developers, consumers, and environmentalists alike are finding CSD increasingly appealing, and it offers a flexible, market-oriented approach to local environmental protection worthy of greater attention.

CSD represents a subtle, but significant, twist to the traditional subdivision design and review process. In a more “traditional” subdivision design — often referred to as the “cookie cutter” approach — all of the developable land within a tract is divided into roads and house lots, typically subject to minimum lot size requirements. Open space typically consists only of the undevelopable portions of the tract, such as wetlands and steep slopes. In other words, most of the land is either built upon, apportioned to individual lots as yards, or surfaced for roads.

In contrast, CSD, also referred to as “open space design,” is basically a “green” version of an approach to subdivision design known as “clustering.” With CSD, developers are allowed to build homes on smaller lots if they leave a portion of the land undisturbed as protected open space. For example, if a “traditional” residential zoning ordinance requires a minimum lot size of 10,000 square feet, a 50-acre parcel could yield roughly 200 houses. In contrast, a CSD-friendly zoning ordinance might allow a developer to build the same 200 houses on 5,000 square foot lots if the other half of the land is left undeveloped. Some communities have even adopted incentive-based ordinances that offer density bonuses to developers that utilize CSD, allowing them to build more homes on a given parcel than would have been allowed under traditional zoning.

Compared to traditional subdivision design, CSD offers the full development potential of a parcel while minimizing environmental impacts and protecting desirable open spaces. The developed portion of the parcel is concentrated on those areas most suitable for development, such as upland areas or areas with well-drained soils. The undeveloped portion of a conservation subdivision can include such ecologically or culturally-rich areas as wetlands, forest land, agricultural land/buildings, historical or archeological resources, riparian zones (vegetated waterway buffers), wildlife habitat, and scenic viewsheds.

Typically, the open space is permanently preserved via easement or dedication and managed through a homeowners association, land trust (or other conservation organization), or local government agency. In some conservation subdivisions, preserved areas have been leased to farmers for small-scale agricultural production, used for community gardens, and even used as community-owned horse farms.

From the developer’s perspective, CSD offers lower development-related expenses with a high-quality, highly-marketable product as the end result. Having homes clustered on smaller lots reduces development costs since there are fewer trees to clear, less land to grade, and less road, water, and sewer infrastructure needed to serve the development.

Conservation subdivisions also target the growing consumer market for homes in natural settings with less property to maintain. Even with smaller lots, housing prices and resale values in conservation subdivisions compare favorably to those in traditional subdivisions. In fact, consumers have shown a willingness to pay a premium for the environmental amenities and quality of life that conservation subdivisions offer. Many people would gladly trade lot size for proximity to natural scenery.

The community-at-large can also benefit from CSD. It can be a useful tool to help address local concerns regarding the loss of environmental resources, farmland and community character. Local governments can also use CSD as a vehicle for creating community-wide open-space networks, reducing the need to purchase and maintain new tracts of public land. Establishing open-space networks and reducing impervious surface cover can benefit the community by providing new recreation opportunities, protecting wildlife habitat, maintaining the ecological and water filtration functions of wetlands and riparian areas, and reducing stormwater runoff and flooding.

The Prairie Crossing development in Grayslake, Illinois is one of the more famous conservation subdivisions. It contains 337 single-family homes on 667 acres, with 350 acres of preserved prairies, farmland, wetlands and lakes and is the western anchor of the 2,500-acre Liberty Prairie Reserve. The development offers over a dozen different home styles that range in size from 1,100 square feet to over 3,400 square feet and in price from roughly $250,000 to $400,000. It also includes a charter school, community horse stables, a community-supported organic garden, and a farmer’s market.

Golf course communities provide an interesting parallel to conservation subdivisions. Planning expert Randall Arendt, the leading proponent of CSD nationally, sometimes refers to conservation subdivisions as “golf course communities without the golf courses.” Surveys have shown that many homeowners in golf course communities do not actually play golf; rather, they enjoy the open space and park-like atmosphere that the golf course provides. Also, the high home values and housing demand in these communities provide an example of the marketability and profit potential associated with open space designs.

Since CSD seems like a win-win for developers, consumers, and environmentalists, why aren’t we seeing more conservation subdivisions in our communities? Put simply, developers are not allowed to build them in many parts of the country. Outdated and inflexible local zoning and subdivision codes make it difficult, if not impossible, for developers to utilize CSD and other innovative designs. In this type of regulatory environment, developers often settle for tried-and-true traditional subdivision designs rather than navigate a long, difficult, and expensive approval process for a non-traditional subdivision.

To encourage the use of CSD, local governments need to modify their comprehensive plans, zoning ordinances, and subdivision regulations to allow conservation subdivisions and to incorporate the flexibility into key development codes – such as lot sizes, building setbacks, and road frontages and standards – needed to implement CSD. Providing incentives such as density bonuses to developers that incorporate CSD into their projects is further step that local governments can take to promote this type of high-quality, ecologically sensitive type of development.

The first step for local governments is to think strategically about what CSD offers for their community, what types of resources are most desirable to target for protection, and how to most clearly define community preservation goals so that developers can easily understand them and incorporate them into their designs. It is also crucial for local governments to understand that CSD is just one of many growth management tools and that it will not be appropriate for all locations and all types of residential development.

Rather, CSD should be thought of as an option that should be made available to developers and consumers interested in ecologically-sensitive development. Communities may find CSD to be an effective tool in their efforts to balance local economic growth with the preservation of environmental resources and community character.

Leonard Gilroy is a senior fellow in urban and land use policy at the Reason Foundation