8. OPEN SPACE RESIDENTIAL DESIGN BYLAW
Overview
Open Space Residential Design (OSRD), also known as conservation subdivision design, is a method of planning residential subdivisions to maximize the amount of preserved open space and protect natural and cultural resources without reducing the number of homes constructed. OSRD is an alternative to conventional subdivision design under existing zoning bylaws, which often mandate a minimum lot size of one acre or more. Even when lot sizes exceed one acre, sprawling lawns, driveways, and other developed surfaces may reduce the integrity of open spaces and natural resource areas.
OSRD involves a four-step planning process:
- Designate open spaces, including “primary conservation areas” such as wetlands and floodplains under regulatory jurisdiction and “secondary conservation areas” with other ecological resources worth protecting, such as steep slopes, mature woodlands, prime farmland, and meadows. The remainder is the buildable area.
- Locate house sites within the buildable area.
- Locate roads and trails to ensure connectivity and access to open spaces.
- Draw lot lines for individual house lots
Municipalities can adopt OSRD bylaws to enable and promote the OSRD process for site design. The bylaw may be structured to allow OSRD “by-right” or even to require the use of OSRD on developments larger than a minimum size or located in sensitive areas such as aquifer recharge zones. Alternatively, the bylaw may allow OSRD by special permit from the Planning Board, as an exception to conventional zoning. By-right OSRD is generally preferable because it gives OSRD parity with conventional zoning, requiring no more burdensome permitting requirements. However, some municipalities prefer the discretion afforded to the Planning Board under a special permit process.
Local Examples
In the Ipswich River watershed, Hamilton, Beverly, and Wilmington have passed OSRD bylaws, and Ipswich has refined a similar cluster bylaw that includes OSRD principles. Ipswich allows clustered subdivisions by special permit, which gives the Planning Board wide latitude to protect community and ecological interests. On the other hand, Wilmington requires new subdivisions on more than 20 acres to use an OSRD approach rather than conventional design.
In 2006, Beverly adopted mandatory by-right OSRD for developments of four homes or more. While Beverly has had a cluster provision in its zoning ordinance for 16 years, it has only been used once since it required special approval from the Zoning Board of Appeals. The by-right OSRD bylaw substantially streamlines the process and makes OSRD the default method of subdivision design.
The development of Partridgeberry Place, a new subdivision near Hood Pond in Ipswich, illustrates the benefits of OSRD. The site originally consisted of 37 acres of forest and forested wetland. After following the four-step OSRD process, 30 acres were set aside as permanent open space, the majority of which was transferred to the Massachusetts Department of Conservation and Recreation state forest system. Twenty lots were then sited in the remaining buildable area.
Resources
Green Neighborhoods, Open Space Residential Design in Massachusetts (html)
Massachusetts Executive Office of Environmental Affairs, Smart Growth Toolkit (pdf)
Water Wise Communities: Index
- Introduction & Using the Handbook
- How Development Affects Water (link to IRWA site)
- Checklist: Is Your Community Water Wise?
- Water Wise Tools:
