Rochester City Zoning Code
ARTICLE 33
Conservation Subdivisions
§ 275-33.1 Purpose.
A.
Master Plan. Promotion of conservation subdivisions is a core goal of the City of Rochester Master Plan. This section is adopted pursuant to RSA 674:21, Innovative Land Use Controls, I(f), Cluster development.
[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II)]
B.
Development of choice. Through density bonuses, cost savings, flexibility in design, and other advantages, it is the City's desire that conservation subdivisions will be the development pattern of choice in the R2 and AG Districts.
C.
Objectives. Conservation subdivisions provide myriad public benefits. The various objectives are to:
(1)
Maintain the rural character of Rochester.
(2)
Create open space that is usable and accessible.
(3)
Provide active and passive recreational opportunities.
(4)
Prevent disruption of existing topography.
(5)
Accommodate natural drainage systems.
(6)
Preserve important ecological features, wetlands, streams, ponds, floodplains, forests, fields, natural vegetation, and tree cover.
(7)
Protect aquifers and groundwater quality.
(8)
Protect significant archaeological resources.
(9)
Discourage fragmentation of undeveloped parcels of land.
(10)
Preserve high quality farm soils and provide opportunities for agriculture.
(11)
Minimize site disturbance, erosion, and sedimentation.
(12)
Promote innovative site design.
(13)
Reduce costs for the developer and maintenance costs for the City by reducing infrastructure.
(14)
Discourage the creation of frontage lots and provide buffers on scenic collector roads.
(15)
Protect scenic views.
(16)
Provide a mix of housing types.
(17)
Encourage bicycle and pedestrian paths.
(18)
Promote efficiency in road and utility layout.
(19)
Locate houses on parts of the land most conducive to development.
§ 275-33.2 Applicability.
A.
Conditional use. A conservation subdivision is a major subdivision involving the creation of a new road. It is allowed by conditional use in the R1, R2, AG, OC, and HC Districts when the Planning Board determines that the proposal meets the intent of a conservation subdivision as expressed in this article, in the Subdivision Regulations, and in the City of Rochester Master Plan. While the conservation subdivision is the preferred form of subdivision it is allowed by conditional use rather than by right in order to ensure that it does meet this intent.
[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II)]
B.
Five acres or five lots. A conservation subdivision may be developed for any parcel of at least five gross acres or where the total number of buildable lots is five or more and which involves the creation of a new road.
§ 275-33.3 General provisions.
A.
Subdivision regulations.
(1)
Special procedures and additional standards for conservation subdivisions may be established in the Subdivision Regulations including the following, as appropriate:
(a)
Procedures for submission, review, and approval.
(b)
Lot orientation.
(c)
Road design.
(d)
Determination of appropriate open space areas with due consideration for natural, scenic, and cultural resources.
(e)
Treatment and ownership of open space.
(f)
Required improvements to open space.
(g)
Dedication of open space to the City or another organization.
(h)
Requirements for covenants, easements, and deed restrictions.
(i)
Standards for a homeowners' association.
(j)
Setting up a stewardship fund for the open space.
(k)
Treatment of individual or community wells and leach fields.
(2)
Absent such special procedures, the ordinary subdivision procedures shall apply.
B.
Meeting all requirements. Obtaining subdivision approval for the number of lots "permitted" in this article is subject to meeting all requirements of the Subdivision Regulations and complying with the requirements of New Hampshire Department of Environmental Services. This is not guaranteed, particularly where there are significant density enhancements.
C.
Dimensions. See Table 19-A, Dimensional Standards - Residential Districts, for dimensional regulations for conservation subdivision lots.
D.
Open space percentage. The proposed open space areas shall consist of a minimum of 40% of the buildable area of the property. All parts of the parcel constitute buildable area except for those lands which are wetlands, steep slopes over 25%, or aboveground utility easements.
E.
Other zoning district. If a portion of a parcel of land is situated in a zoning district in which conservation subdivisions are not permitted, that portion of the land shall not be developed as a conservation subdivision.
F.
Frontage lots. If any recently created lot has been subdivided from the parent tract within two years prior to the date that the application for the conservation subdivision is submitted (or from the date that a conventional subdivision is submitted, if it is subsequently modified to be a conservation subdivision), then the total number of lots permitted in the conservation subdivision shall be reduced by 1.5 lots for each such frontage lot formerly created.
G.
Frontage on new roads. All new lots shall have frontage only on newly created local roads on the interior of the subdivision.
H.
Buffer. The portion of the tract fronting on existing roads shall be preserved as a buffer to the maximum extent practical.
I.
Merging of frontage lots. Undeveloped existing frontage lots that are part of the overall tract shall be merged with the remainder of the tract as part of a resubdivision for the development, to the extent practical.
J.
Adjacent development. Where proposed lots will be contiguous to existing single-family dwellings, the Planning Board may, at its option, require that the proposed lots conform to the dimensional requirements for conventional subdivisions or that other buffering methods be used.
§ 275-33.4 Base density.
The base density for a conservation subdivision shall be determined by one of the following two approaches, as stipulated by the Planning Board:
A.
Yield plan approach. The yield plan is the theoretical layout showing the lots that would reasonably be approvable and buildable under a conventional subdivision. The Planning Board must vote to endorse the yield plan as meeting the objective of this subsection. The number of lots in the endorsed yield plan is then multiplied by 1.3, which is the base density bonus for a conservation subdivision.
B.
Adjusted tract acreage approach. The adjusted tract acreage approach is used to derive an objective and consistent measure of the total carrying capacity of the tract. The method is less subjective than the yield plan approach but it is not as good an indicator of what could be built conventionally. The steps are to:
(1)
Determine gross tract acreage;
(2)
Subtract the acreage of any existing road rights-of-way and existing rights-of-way for overhead utilities;
(3)
Subtract the acreage of very poorly drained soils, ponds and streams to ordinary high-water mark, and slopes of 25% or greater;
(4)
Subtract 1/2 the acreage of non-wetland floodplains;
(5)
Multiply by 0.75 (allowance for new roads, other infrastructure, wetland buffers, poorly drained soils, inaccessible upland areas, and typical loss of density due to platting constraints);
(6)
Divide by the minimum permitted lot size for a conventional single-family subdivision in the district; calculate proportionally if the tract lies in two zoning districts (see Table of Dimensional Standards in Article 19); and
(7)
Multiply by 1.3 (density bonus).
§ 275-33.5 Base density bonus.
Conservation subdivisions receive a base density bonus of 30% beyond conventional subdivisions based upon yield plans or assumed in the adjusted tract acreage approach. Additional density enhancements beyond the base density bonus may be awarded as specified in § 275-33.6 below.
§ 275-33.6 Density bonus enhancements.
Density enhancements beyond the base density determined above shall be awarded where the Board determines that the applicant meets the intent of the requirements below. Each enhancement percentage shall be based upon the number of dwelling units established in the base density. Multiple enhancements are cumulative and shall be added to the base density (except that only one additional open space enhancement shall be allowed among the three alternatives). Appropriate easements, covenants, and/or deed restrictions shall be incorporated to protect the enhancements where deemed necessary by the Board.
A.
Additional open space enhancement.
(1)
A five-percent enhancement shall be awarded where the percentage of open space as defined in this article exceeds 50%.
(2)
A ten-percent enhancement shall be awarded where the percentage of open space as defined in this article exceeds 60%.
(3)
A fifteen-percent enhancement shall be awarded where the percentage of open space as defined in this article exceeds 70%.
B.
Open space access/linkage enhancement. A five-percent enhancement shall be awarded when at least one of the following three is incorporated in the plan:
(1)
Special trail designs are incorporated in the open space areas.
(2)
The general public is granted access to the open space.
(3)
The open space/trail network is linked with open spaces/trail networks on an adjoining parcel(s).
C.
Natural resources enhancement. A five-percent enhancement shall be awarded when recommended by the Conservation Commission where significant environmental resources are protected, including specimen trees, other important vegetation, boulders, rock outcrops, and/or important wildlife habitats.
D.
Agriculture enhancement. A five-percent enhancement shall be awarded where the development protects agriculturally valuable lands and allows for agricultural use in perpetuity through an appropriate legal instrument. The affected lands must constitute a significant proportion of the open space. It is required only that permission be granted in a way that reasonably provides for agricultural use; whether the lands are actually placed in agricultural use does not affect the validity of this enhancement.
E.
Viewshed enhancement. A five-percent enhancement shall be awarded where lands or corridors that contribute significantly to the visual landscape, such as open fields containing stone walls, are protected.
F.
Historic resources enhancement. A five-percent enhancement shall be awarded when recommended by the Historic District Commission where historically or architecturally significant buildings or structures are preserved, restored, and/or protected, as appropriate.
G.
Architectural design enhancement. A five-percent enhancement shall be awarded for establishing architectural standards for single-family houses to promote excellence in building design. The standards shall be established either through private covenants or as conditions of approval. The architectural regulations contained in the Site Plan Regulations, Article 14, Historic Overlay District, and the Architectural Jewels series in the Rochester Times Newspaper may be used for guidance.
H.
Other enhancement. A five-percent enhancement may be awarded for any other measure which the Planning Board deems worthy, such as making a contribution to the school or other department to mitigate costs of serving the project, contributing to a stewardship fund to monitor the open space if donated to a nonprofit organization, instituting innovative methods of protecting resources, or offering special traffic mitigation approaches.
§ 275-33.7 Allowed uses.
[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. II)]
All uses permitted in the zoning district within which the conservation subdivision is located are permitted in the conservation subdivision under the same terms. Two-family, three-family, and four-family dwellings are permitted in conservation subdivisions provided:
A.
At least half of the proposed units are single-family dwellings;
B.
A system of street blocks or a modified grid is used;
C.
The units are carefully integrated into the development (such as placing the units on larger lots at intersections, fronting on greens, or on alternating or cross streets);
D.
The architectural designs provide for a harmonious fit with single-family dwellings.
E.
The development standards under Article 5, Residential Zoning Districts, shall apply;
F.
None of these multifamily uses are located within 200 feet of the project boundary; and
G.
Each unit shall be considered equivalent to one house lot for density purposes.
§ 275-33.8 Zero lot line subdivision.
A zero lot line subdivision is a special technique where side setbacks are reduced on the same side of all adjoining lots to accommodate usable side setbacks. (Example: All of the houses along one block would have no side setback on the southerly side but an extra large setback on the northerly side, resulting in usable side setbacks for all properties on the northerly side.) A zero lot line subdivision is permitted subject to the following:
A.
One-foot setback. The minimum side setback for the building and all appurtenant elements of the building (chimney, porches, windowsills, etc.) shall be at least one foot (rather than zero feet, to allow for error).
B.
Block. The same standards shall apply to all lots along an entire section or block to ensure adequate spacing between houses.
C.
Privacy. Special design standards shall be incorporated to foster privacy in side setbacks, such as through prohibitions on windows on the facing side elevation of the adjacent house, and are established in deeds or through other appropriate mechanisms.
D.
Usability. Special standards are incorporated to foster quality design and usability of side setbacks and are established in deeds or through other appropriate mechanisms.
E.
Clearance zone. A minimum six-foot clearance is established (on one or both lots) by easement or other method alongside the facade of the building on the reduced setback side. The purpose is to allow for firefighting access and maintenance for both lot owners. No fence or other obstruction may be constructed within this clearance zone.
F.
Total side setbacks. The total side setbacks for the subject district must be maintained. (Example: If the ordinary side setback in the zoning district is 15, then the total of both side setbacks in the zero lot line subdivision must total at least 30.)
G.
Fire Department. Approval by the Fire Department to ensure all necessary access for firefighting.
§ 275-33.9 Open space.
A.
Undeveloped. Areas designated as open space shall be set aside as such in perpetuity, free of any roads, development or subdivision (except for minor lot line adjustments that do not decrease the amount or quality of open space).
B.
Allowed uses. The following uses and activities are allowed within the open space by right:
(1)
Agriculture;
(2)
Forestry;
(3)
Gardens;
(4)
Paths;
(5)
Outdoor recreational activities;
(6)
Open-air recreational structures; and
(7)
Cemeteries.
C.
Discretionary uses. The Planning Board may approve any of the following uses and activities within the open space at its discretion:
(1)
Underground utilities;
(2)
Individual or common leach fields and wells;
(3)
Small accessory structures; and
(4)
Drainage structures.
D.
Separate lots. The open space shall be established as one or more separate open space lots, independent from individual house lots.
E.
Frontage. The open space lots shall have at least 10 feet of frontage to allow for reasonable access but wider frontages are preferred.
F.
Public access. Allowing for public access to open space is encouraged but it is not required. However, residents of the subdivision may not be restricted from access to the open space.
G.
Noncontiguous tracts. At its discretion, the Planning Board may approve a conservation subdivision that incorporates two noncontiguous tracts, one for development on which the dwelling units will be developed, and a second that will be preserved as open space.