In the conservation subdivision River Valley, 34 houselots average 36,000 square feet (0.85 acres, just under one acre) each, on the 85 acre site, preserving 48.5 acres, almost two-thirds of the site, as permanently protected open space. Click image above for larger image.

I like Randall Arendt’s approach to conservation subdivisions: “Do It Backward”.

First, set aside land for conservation. This eliminates the left-over conservation areas that are traditionally created.

Last, divide up the land into parcels. This allows the developer to penpoint the prime developable area, while maintaining conservation areas.

According to Randall Arendt, “The term ‘conventionally designed subdivision’ refers to residential developments where all the land is divided into houselots and streets, with the only open space typically being undevelopable wetlands, steep slopes, floodplains, and stormwater management areas.”

“The term ‘conservation subdivision design’ refers to residential developments where half or more of the buildable land area is designated as undivided, permanent open space” at a neutral density (same number of homes) to existing zoning.

Let’s have more of the first, and less of the later. Planners (and homebuilders), are you learning and listening?

Note: The original site plan for River Valley called for a conventional subdivision of 34 house lots of 80,000 square feet (just under two acres) each on the 85 acre site, taking up all but the unbuildable land.

Text courtesy Randall Arendt, Conservation Design for Subdivisions (A GREAT book if you don’t already own it!) Images courtesy LandChoices, and Randall Arendt, Growing Greener: Putting Conservation into Local Plans and Codes, Island Press, 1999 (planners, this is a must read for ALL of you!)