MANDATES & INCENTIVES FOR CONSERVATION DESIGN
User Tips: Conservation Subdivision Standards
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Many Pennsylvania municipalities have adopted the “four-step approach” to conservation
subdivision design, known as Growing Greener, within their local subdivision and zoning
ordinances. This four-step conservation subdivision design approach can generally be described
as:
- Identify Conservation Areas;
- Locate residential sites within the Potential Development Areas where views of open space are maximized;
- Align streets and trails;
- Draw lot lines.
- A Conservation Subdivision process operates in the reverse of the traditional subdivision process. In the traditional approach a developer first designs the road network and then subdivides lots, which results in little to no preservation of open space or natural features. Using the Conservation Subdivision approach, the developer begins by designating sensitive land areas and then determines where lots and roads should be located. Between 50-70% of a development site is required as open space.
- The more flexible site design standards of the Conservation Subdivision process will be an important tool for allowing some new development along the AT while significantly protecting natural resources and minimizing visibility of the new development from the Trail. GIS viewshed and natural features layers (see Principle 2) are available to analyze as part of the Conservation Subdivision process.
- Where Conservation Subdivision is being used for farmland preservation, the site design standards should maintain the farming viability of the preserved agricultural lands.
- Consider Conservation Subdivision as the permitted use and conventional subdivisions only by conditional use to promote better site design and resource protection in a district.
- Lot Averaging is an incentive that allows developers a reduced minimum lot size and width if certain conditions (e.g., increased open space, preservation of natural features) are met.
- To be eligible for lot averaging, many municipalities require a minimum lot site size of at least 10 acres with contiguous parcels and specify qualifying zoning districts (e.g., agricultural preservation, rural residential density).
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Lot averaging permits flexibility in lot size and dedication of open space. Here are two
examples from the Albany Township Ordinance:
- Instead of requiring 5-acre minimum lots, a 10-acre tract may be subdivided into a 2-acre and an 8-acre lot. In such case, a conservation easement, enforceable by the Board of Supervisors, shall be required on the 8 acre lot to ensure that the lot is not further subdivided and to protect any portions of such lot that have important natural features, such as portions along a creek.
- A 10 acre tract may be subdivided into two 2 acre lots, if 6 acres are dedicated to the State Game Commission, to a homeowner association or to another approved entity to serve as common open space.
- To incentivize conservation design, a municipality can allow diverse housing types. Allowing a mix of housing types (e.g., single-family, townhomes, apartments, etc.) and/or a mix of market-rate and affordable housing in one neighborhood or block is often desirable to a municipality and can be encouraged with conservation design.
- Additional units (increased density) and/or flexibility with street design are two very valuable incentives to provide developers in exchange for natural or historic preservation measures.