Open Space Residential Design (OSRD)
Case Study

Wild Pasture Estates, Rowley, MA

Wild Pasture Estates is a 30-unit housing project that was recently permitted under the OSRD provisions of Rowley's Zoning Bylaw. Construction of the project began in the spring of 2005 on a 63-acre parcel of undeveloped open space. Of the 63 total acres, 37 acres will be maintained as open space. The general design of the development used three clusters of homes to concentrate the development envelope between two large tracts of conservation area. Restrictions for these areas were subsequently recorded with the Registry of Deeds.

Aerial view plan for Wild Pasture Estates.The Bylaw

The Town of Rowley has been addressing the issue of open space development in their Zoning Bylaw for over a decade. These efforts began with a standard cluster zoning bylaw that provided guidelines and incentives for concentrating residential development through the subdivision process. Over the years, the Planning Board and other local agencies identified the need for a more flexible resource-oriented approach through continued inter-agency discussions and the development of their Master Plan. As a result, the cluster bylaw has gradually evolved into the existing OSRD bylaw after several revisions adopted through Town Meeting. The Planning Board played the lead role in facilitating a dialogue at Town Meeting and was able to successfully address any concerns regarding six separate sets of Bylaw revisions.

In its current form, the Rowley OSRD Bylaw uses the fundamental tenets of OSRD with the four step site planning process.

  1. Identify all conservation areas to determine the potentially developable area.
  2. Locate housing sites.
  3. Align streets and trails.
  4. Draw in the lot lines, if the OSRD is not a condominium development.

Discussions with Rowley's citizenry revealed that many people were concerned that a more flexible approach to development would allow for a higher volume of residential units than what is allowed through conventional zoning bylaw provisions. To help address these concerns, the individuals who drafted the bylaw added another level of analysis to the Yield Plan. As with most OSRD Bylaws, the Rowley Bylaw requires a Yield Plan to determine how many units of housing could be developed under conventional zoning provisions. This plan is similar in form and content to a preliminary subdivision plan and shows the basic lotting that could occur with a conventional approach. However, in addition to a physical site plan, the yield analysis in the Rowley OSRD Bylaw requires a basic mathematical calculation to substantiate the number of units illustrated in the conventional lotting layout. The formula for potential site yield is as follows:

formula for potential site yieldAn applicant is required to both develop a Yield Plan and perform the computations above as part of the site yield analysis. The method that produces the lower number is the one chosen for the final yield.

As an incentive to developers, the bylaw provides for density bonuses for historic preservation, creation of affordable housing, or protection of additional open space. The density bonus for the OSRD development cannot exceed 50% of the basic maximum number, which is determined by the basic "by right" zoning regulations of the underlying district. Density bonuses can be awarded in the following circumstances:

  1. For each 10% of the site (over and above the required 50%) set aside as open space, a bonus of 5% of the Basic Maximum Number may be awarded.
  2. For every dwelling unit set aside as affordable in perpetuity, one dwelling unit may be added as a density bonus.
  3. For every historic structure preserved and subject to a historic preservation restriction, one dwelling unit may be added as a density bonus.

* Primary Conservation Area is defined as "Areas consisting of wetlands, riverfront areas, or floodplains protected by the Wetlands Protection Act, M.G.L. Ch. 131, § 40, land included within the Floodplain and Watershed Protection District, or land protected by restrictive order under M.G.L., Ch130, § 105."