The amendment also would increase the minimum site required to build cluster zoning from 10 acres to 15. Under cluster zoning, minimum individual lot sizes are reduced to allow for open space elsewhere in the development.
Residents for an Environmental Sustainable Thornbury (REST) opposed the proposal at a meeting Wednesday night on the ground that even a 15-acre minimum site is not acceptable.
REST is pushing for a 40-acre minimum, which would mean only a handful of sites could be developed under cluster zoning, member Harry Zane said. Many more sites would qualify with a 15-acre minimum.
Zane said that maintaining large sections of open space with only 15 acres would be more difficult than setting aside the space on a 40-acre site.
After a two-hour hearing, packed with more than 50 Thornbury residents, the supervisors tabled the amendment. They now have 90 days to act on it.
As Supervisor William Lovejoy pointed out, Thornbury is a rural township surrounded by more-developed areas - ``the hole in the doughnut,'' as Lovejoy put it.
Most of the township is zoned R-1, which calls for about two acres per home. The current cluster ordinance allows about 13 homes on 10 acres, with 40 percent of the land dedicated to open space.
Supervisors Chairman George Morley said he would be interested in looking at all of the township's high-density zoning in an effort to remove the planned residential development (PRD) zoning that allowed construction of two large Toll Bros. subdivisions in the township. But before the PRD can be removed, other high-density classifications - such as the cluster zoning - must be in place to fulfill legal requirements, he said.
Morley said it was a delicate balancing act to have strict zoning that maintained the country feel of the township but still fell within the legal requirement that townships allow varied residential densities.
``We're trying to tread just far enough without getting attacked,'' he said.
Morley said the supervisors and members of the Planning Commission would hold a joint meeting soon on the proposed amendment.