The basic principle of “open space zoning” based upon the technique of “clustering” is by no means limited to townhouses, apartments, or condominiums, as is typical in many planned unit developments. In fact, the classic rural village settlement pattern is a superb example of single-family clustering, sometimes with a central green constituting the permanently preserved open space.
- The intent of cluster development ordinances is simple: develop less land while allowing the same number of housing units that would be permitted under conventional subdivision ordinances. By allowing the same number of units, landowners and developers are not penalized financially for using a cluster development strategy.
- There are three basic goals of cluster development: preserving open space; protecting critical ecological habitats; and preserving agricultural land.
- Cluster development protects open space by establishing the number of units allowed per parcel completely independent of any minimum lot size.
- Many communities offer voluntary clustering ordinances, allowing the developer to choose between a conventional subdivision or a cluster development.
- Clustering is particularly appropriate in rural areas that wish to remain rural while accommodating additional growth.
- Clustering offers an alternative to large lot rural sprawl which consumes open space and creates lots that are too small for farming.
- Clustering places development in less sensitive areas preserving forested land, steep slopes, wetlands and valuable landscape features.
- Cluster housing developments have become very popular in the rural areas of Wayne, Lake, Geauga, Medina, Summit and Madison Counties in Ohio.
- Clustering can save infrastructure costs by reducing the length of roads and utility lines to new developments.
Clustering Options
This plan, developed by Calthrope and Associates, shows several different styles and sizes of cluster development. The most valuable open space, with an existing pond and prairie, is preserved in it natural state.
“Homes clustered in groups ranging from about 5 to 30 homes. Each cluster has a central green, which functions as a gathering and recreation space for the community. Streets circulate around the space, providing convenient parking and enhancing safety and the overall activity level.
Clusters are differentiated by their distinctive features. The cluster at the top integrates an important community component through the incorporation of a civic feature; in this case an interpretive center that showcases the wildlife and habitat of the region. The larger cluster in the middle, situated near the high point of the area, includes an overlook that is linked to a trial system that passes through the site. The clusters at the bottom of the drawing have lots that are sufficiently large to allow small agricultural plots or additional open space.
Although the streets within the cluster developments do not form an interconnected network, pedestrian paths and trials facilitate walking and cycling by linking different neighborhoods and clusters. Clustering will not significantly reduce dependence on the automobile, since homes are still far from major retail, schools, and offices, and it is difficult or impossible to serve the small, dispersed clusters with transit. However, bicycling may be a viable alternative to driving in some situations if a regional network of trails or bicycle-friendly roads exist, and distances are not too long.”
A Hierarchy of Uses in Cluster Developments
This concept, developed by Calthorpe and Associates shows the hierarchy of allowable activities and uses in cluster development. Homes, garages, and other structures occupy a small building “envelope” that is clustered around a community green. Typically, this green is maintained through a homeowners’ association. Gardens, lawns, and pets are permitted in a larger “active open space” area within each lot.
The remainder and majority of each lot, typically 50 to 70 percent, is set aside as natural open space, where activities are restricted to those that do not disturb the natural landscape or habitat.
Beyond the private lots is the preserved natural habitat or farmland. A land trust or public agency should maintain permanent control over this land.
"Clustering" also called open space development, is a preferable alternative to large lot "rural sprawl" which consumes open space, privatizes all land and creates lots that are too small for farming or meaningful habitat protection.
Images Reprinted by permission of the Minneapolis Council/Calthorpe & Associates