Groton Open Space Association

KKC Illustrates Spreadsheet Planning For Zoning, Planning Boards

GROTON — The Zoning and Planning Commissions have been left with much complex material to digest following a March 4, 2009, workshop presentation by Kendig Keast Collaborative, the Midwest firm that the town has hired to help rewrite its land use regulations.

Outlines of KKC’s approach had been made public previously. However, the early-March presentation, by KKC principal Mac Birch, brought the concept down to ground level in Groton. Mr. Birch applied KKC’s “resource protection and site capacity” method of calculating allowable development to four actual properties in Groton. The properties — not at present known to be targets of development plans — were chosen for illustrative purposes.

The public was allowed to attend the joint Planning-Zoning Commission workshop in the Town Hall Annex but could not take part in the discussion.

KKC has said that one of its goals is to eliminate disputes in planning by providing a quantified basis for determining the number of units that may be built on a given tract of land. Details of the calculations presented March 4 are on view at the town’s website. They show how that goal of no-strife development would be realized if KKC’s plan is adopted in land-use rule amendments.

In general terms, KKC formulas determine the number of permitted units on a given tract this way:

A buildable area is determined arithmetically on a spreadsheet. It is total acreage of a tract in acres minus “protected acres.” So-called protected acres are those that host water bodies, wetlands, woodlands, steep slopes, and moderate slopes that are located in sewer avoidance areas. The degree of protection afforded these geographic features varies from 10% of woodland acreage outside RU districts to 120% for bodies of water in the Water Resource Protection District.

Buildable area is multiplied by a density factor to determine the number of permitted lots. Neglecting some details, a density factor is the “other side of the fraction,” in Mr. Birch’s words. For example, 1/2-acre zoning equates to a density factor of 2/1, or 2 units per acre.

Of great interest to GOSA in particular was Mr. Birch’s discussion of a 64.1-acre tract on Hazelnut Hill owned by Groton Lenders LLC. The land, known as the Sheep Farm, has been optioned for purchase by the Groton Open Space Association. Mr. Birch’s spreadsheet-based calculation came up with 79 permitted units on the rugged tract that slopes down to Fort Hill Brook. (The formula calculation: 64.01 total acres minus 21.72 protected acres = 42.29 acres, times a density factor of 1.89 = 79 lots.)

Before the land was optioned to GOSA, it had been scheduled for a development of approximately 34 units. Thus, the KKC formula would sanction a development of about 230% of the density proposed by a developer.

Both Planning Manager Matthew Davis and Planning Director Michael Murphy played down the increased density as a factor in evaluating environmental impact.

Mr. Davis said, “We need to separate out the density bugaboo. It’s about design.” Mr. Murphy indicated that a 79-lot development on the sheep farm would have had a different design from what the developer proposed. “You can do more environmental protection with a different form of housing,” he said.

Mr. Davis said the Sheep Farm could present a chance for “flexible and innovative design in an area that is close to the Pequot Health Center and I-95… It is an opportunity for smart growth and smart design.” He added that the figure of 79 lots had been arrived at by applying a zero level of protection to moderate slopes, which occupy 8.57 acres of the area according to information presented by KKC. He said a higher level of protection would have resulted in a significantly lower number of units, but he gave no figures. He indicated the ultimate protection level for moderate slopes outside of no-sewer areas is still to be determined.

Mr. Birch said, “It’s questionable to put open space where there are utilities and infrastructure because it calls into question the viability of the utilities.”

The other properties analyzed by Mr. Birch included the 197-acre Whittle Farm, which would qualify for 90 lots; the 57-acre Wolfebrook West, 67 lots; and the 201-acre Giordano property, 82 lots.

Mr. Birch mentioned that spreadsheets based on the KKC system can be posted by communities on the internet, meaning “developers can plug in numbers and get the same result as staff.”

Also of interest to conservationists was the general sharp shrinkage of protection factors since KKC’s report in September 2008. For example, the “conceptual resource protection standards” listed on P. 16 of the KKC report distributed then would have given 90% protection to woodlands in RU districts such as the zone in which the Sheep Farm is located, vs 20% in the March 4 report. Moderate slopes of 15% to 25% would have been 85% protected, vs 0% outside sewer avoidance areas. The September document would have afforded protection to riparian and wetland buffers of 90%. These are not mentioned in the March 4 report. (A minor shift on the other side of the ledger: the September report had 95% protection for steep slopes, while the March 4 report stipulated 100%).