The standards for resource conservation, as set forth in this Article, shall apply to all land subdivision and developments in the Township. The standards for Greenspace Land delineation shall apply to all land subdivision and developments within the Township.
A. General Standards to Minimize Adverse Impacts
All subdivisions and land developments shall avoid or minimize adverse impacts on the Township's natural, cultural and historic resources, as defined below.
B. Groundwater Resources
This section is intended to ensure that the Township's limited groundwater resources are protected for purposes of providing water supplies for its residents and businesses, and to protect the base flow of the Township's surface waters. These regulations shall be applied in conjunction with all other provisions of this ordinance dealing with groundwater conservation and replenishment.
1. The proposed subdivision and land development of any tract shall be designed to cause the least practicable disturbance to natural infiltration and percolation of precipitation to the groundwater table, through careful planning of vegetation and land disturbance activities, and the placement of streets, buildings and other impervious surfaces in locations other than those identified on the Existing Resources and Site Analysis Map as having the greatest permeability where precipitation is most likely to infiltrate and recharge the groundwater.
C. Stream Valleys, Swales, Springs, and Lowland Areas
The Township's Open Space Plan describes and maps stream valleys (which include stream channels and flood plains), swales, springs and other lowland areas as resources that warrant restrictive land use controls because of flooding hazards to human life and property, their ground water recharge functions, their importance to water quality and the health of aquatic communities, and their wildlife habitats. They are generally poorly suited for on-site subsurface sewage disposal systems.
1. The following activities shall be minimized:
a. Disturbance to streams and drainage swales
b. Disturbance to year-round wetlands, areas with seasonally high water tables, and areas of surface water concentration.
c. Because of their extreme limitations, stream valleys, swales and other lowland areas warrant designation as Greenspace lands. They may also require adjoining buffer lands to be included in the Greenspace, to be determined by an analysis of the protection requirements of such areas on a case-by case basis. In certain instances, seasonal high water table soils may be excluded from the Greenspace where it can be demonstrated that they are suitable for low density residential uses and conventional on-site sewage systems.
D. Woodlands
1. Woodlands occur extensively throughout the Township, often in association with stream valleys and wet areas, poor and erodible agricultural soils, and moderate to steep slopes.
2. Woodland conditions within the Township vary with respect to species composition, age, stocking, and health. They range from relatively recent post-agricultural young stands to mature mixed-age forests. Most woodlands in the Township represent one or more of the following resource values:
a. As soil stabilizers, particularly on moderate to steep slopes, thereby controlling erosion into nearby streams, ponds, impoundments and roads. A closely related function is their enhancement of ground water recharge.
b. As a means of ameliorating harsh micro climatic conditions, in both summer and winter.
c. As a source of wood products, i.e., poles, sawtimber, veneer and firewood.
d. As habitats for woodland birds, mammals and other wildlife.
e. As recreation resources for walkers, equestrians, picnickers and other related outdoor activities.
f. As visual buffers between areas of development and adjacent roads and properties.
3. Because of their resource values, all woodlands on any tract proposed for subdivision or land development shall be evaluated by the applicant to determine the extent to which such woodlands should be designated partly or entirely as Greenspace or development lands. Evaluation criteria shall include:
a. Configuration and size.
b. Present conditions, i.e., stocking, health and species composition
c. Site potential, i.e., the site's capabilities to support woodlands, based upon its topographic, soil and hydrologic characteristics.
d. Ecological functions: i.e., in protecting steep slopes, erodible soils, maintaining stream quality and providing for wildlife habitats.
f. Relationship to woodlands on adjoining and nearby properties and the potential for maintaining continuous woodland areas.
4. The evaluation of the tract's woodlands shall be undertaken by a forester, landscape architect, horticulturist or another qualified professional acceptable to the Township. This evaluation shall be submitted as a report and made a part of the application for a preliminary plan. At a minimum, that report shall include one or more maps indicating boundaries and conditions of woodland areas accompanied by a report addressing the criteria in paragraph I above.
5. In designing a subdivision and land development plan for any tract, the applicant shall be guided by the following standards:
a. Healthy woodlands exceeding one acre shall be preserved and designated as Greenspace areas, to the maximum extent possible. Proposed site improvements shall be located, designed and constructed to minimize the loss or degradation of woodland areas.
b. Subdivisions shall be designed to preserve woodlands along roadways, property fines and lines occurring within a site such as streams, swales, stone fences and hedgerows. Such lines and the native vegetation associated with them shall be preserved as buffers between adjacent properties and between areas being subdivided within a property. Preservation shall include ground, shrub, understory and canopy vegetation.
c. Disturbance or removal of woodlands occupying environmentally sensitive areas shall be undertaken only when approved by the Board and on a limited, selective basis to minimize the adverse impacts of such actions. This shall include but not necessarily be limited to, vegetation performing important soil stabilizing functions on wet soils, stream banks and sloping lands.
d. No clearing or earth disturbance (except for soil analysis for proposed sewage disposal systems) shall be permitted on a site before the completion of subdivision and land development agreements. The determination of sight distance clearances along roadways shall be made graphically and not by clearing on-site prior to final plan approval.
E. Upland Rural-Agricultural Areas
These areas comprise fields, pastures, meadows, and former agricultural areas in early stages of woodlands succession, with fences, stone walls, tree copses and hedgerows, typically bordered by stream valleys and upland woodlands. These comprise the Township's historic working landscape, dotted with historic houses, barns and other structures. They give the Township much of its rural character. They also contain the greatest concentration of prime agricultural soils. Because of their openness and high visibility, development in these areas is Rely to be most readily seen and disruptive to the historic landscape. They sometimes provide habitat for wildlife, in conjunction with nearby woodlands and stream valleys. However, it is recognized that these areas also frequently offer the fewest constraints for development.
1. Several elements of these working landscapes lend themselves to incorporation into the Township's Greenspace network. These include prime agricultural soils and natural features which visually punctuate the landscape, such as hedgerows, tree copses, stone walls, and visually prominent places such as knolls and hilltops.
2. These areas can also accommodate development, with preferred locations being the non-prime agricultural soils and lower topographic settings where development will be visually less obtrusive. Compact clustered residential designs, with coordinated architectural and landscape architectural themes, are encouraged in highly visible locations where future development cannot be avoided (such as at the far edge of open fields).
F. Slopes
Moderately sloping lands (12 to 20 percent) and steeply sloping lands (over 20 percent) are prone to severe erosion if disturbed. Erosion and the resulting overland flow of soil sediments into streams, ponds and public roads, are detrimental to water quality and aquatic life, and a potential hazard to public safety.
1. Areas of steep slope shall be preserved in accordance with Article 12 of the Zoning Ordinance and as required below.
2. All grading and earthmoving on slopes exceeding 12 percent shall be minimized.
3. No site disturbance shall be allowed on slopes exceeding 20 percent except grading for a portion of a driveway accessing a single family dwelling when it can be demonstrated that no other routing which avoids slopes exceeding 20 percent is feasible.
4. On slopes of 12 to 20 percent, the only permitted grading beyond the terms described above, shall be in conjunction with the siting of a single family dwelling, its access driveway and the septic system (which should typically be designed with a long, narrow drainage field following the land contours.
5. Grading or earthmoving on all sloping lands of 12 percent or greater shall not result in earth cuts or fills whose highest vertical dimension exceeds six feet except where in the judgment of the Board no reasonable alternatives exist for construction of roads, drainage structures and other public improvements, in which case such vertical dimensions shall not exceed 12 ft. Roads and driveways shall follow the line of existing topography to minimize the required cut and fill. Finished slopes of all cuts and fills shall be as required to minimize disturbance of natural grades.
G. Other Significant Natural Areas and Features
Natural areas containing Tare or endangered plants and animals, as well as other features of natural significance exist throughout the Township. Some of these have been carefully documented, e.g., by the Pennsylvania Natural Diversity Inventory, whereas for others, only their general locations are known. Subdivision applicants shall take all reasonable measures to protect significant natural areas and features either identified by the Maps IA through IC in the London Britain Township Open Space, Recreation and Environmental Resource Plan or by the applicant's Existing Resources and Site Analysis Map (as required in Section 401A31 by incorporating them into proposed Greenspace areas or avoiding their disturbance in areas proposed for development.
H. Historic Structures and Sites
The Township's documented historical resources begin with the Native Americans in the early 18th century and extend through its colonial agricultural, residential and industrial development in the late 18th and 19th centuries. Many of the Township's historic structures and sites have been extensively researched and remain intact. The Township's extensive historic records are maintained by its Historical Commission.
1. Plans requiring subdivision and land development approval shall be designed to protect existing historic resources of all classes. The protection of an existing historic resource shall include the conservation of the landscape immediately associated with and significant to that resource, to preserve its historic context. Where, in the opinion of the Board, a plan will have an impact upon an historic resource, the developer shall mitigate that impact to the satisfaction of said Body by modifying the design, relocating proposed lot lines, providing landscape buffers, or other approved means.
2. Municipal participation, review and approval of the applicant's interaction with the Pennsylvania Historical and Museum Commission with regard to the preservation of historic resources.
1. Historic Rural Road Corridors and Scenic Viewsheds
The Township's Open Space, Recreation, and Environmental Resources Plan identifies a number of historic rural roads in various parts of the Township. All applications for subdivision and land development shall attempt to preserve the scenic visual corridors along such roads by incorporating them into Greenspace areas or otherwise providing for building setbacks and architectural designs to minimize their intrusion. In instances, where such designs fail to satisfactorily protect corridors, applicants will be required to provide naturalistic landscape buffers to minimize their adverse visual impacts. The species required for such buffers shall be selected on the basis of an inventory of tree and shrub species found in existing hedgerows and along wooded roadside edges in the vicinity of the development proposal.
Trails
1. See Section 511
2. The land area permanently designated for trails for public use may be credited toward the open space requirement described in Article VII of this Ordinance and Article XIII of the Zoning Ordinance.
A. Resource Inventory and Analysis.
The tract's resources shall be delineated on an Existing Resources and Site Analysis Map, as required in Section 401A3
B.. Four-Step Design Process.
Following the resource inventory and analysis, all residential subdivisions with Greenspace lands shall generally follow a four-step design process as described below. Applicants will be required to document the design process as described in Section 401A3.
1. Step I - Delineation of Greenspace Lands and Development Areas
Greenspace lands and development areas shall be delineated according to the following procedure, as illustrated below, using as an example a hypothetical 50-acre subdivision parcel.
a. All lands deducted from the gross tract to determine adjusted tract size, i.e., floodplains, wetlands and slopes over 20 percent, shall be delineated in their entirety as "Primary Conservation Areas", comprising 10 acres in the illustration.
b. Additional minimum acreage requirements for Greenspace areas consist of "Secondary Conservation Areas". In the example, a minimum of 50% of the total tract acreage (or 15 acres) must be Class B Greenspace Lands.
c. Total Greenspace area requirements are the sum of Primary and Secondary Conservation Areas.
d. The locations and boundaries of Primary Conservation Areas shall follow the actual boundaries of floodplains, wetlands and slopes as indicated in paragraph I above.
e. The locations and boundaries of Secondary Conservation Areas shall be based upon the applicant's analysis of the tract's resource features, using the design standards in Section 703. The applicant shall also be guided by any written recommendations provided by the Township regarding the delineation of Secondary Conservation Areas lands, following the Site Inspection or the Pre-Sketch Conference.
f. Development areas constitute the remaining lands of the tract outside of the designated Greenspace Lands, which in the above example consist of 20 acres, where house sites, streets and lots are to be delineated in accordance with steps 2, 3 and 4 below.
2. Step 2: Location of House Sites
a. Applicants shall identify house site locations in the tract's designated development areas, designed to: fit the tract's natural topography, served by adequate water and sewerage facilities, and provide views of and access to adjoining Greenspace areas (without encroaching upon them in a manner visually intrusive to users of such areas). House sites should be located no closer than 100 feet and 50 feet from Primary and Secondary Conservation Areas, respectively.
3. Step 3: Alignment of Streets and Trails
a. With house site locations identified, applicants shall delineate a street system to provide vehicular access to each house in a manner conforming to the tract's natural topography and providing for a safe pattern of circulation and ingress and egress to and from the tract.
b. Streets shall avoid or at least minimize adverse impacts on the Greenspace areas. To the greatest extent practicable, wetland crossings and new streets or driveways traversing slopes over 12 percent shall be avoided.
c. Street connections shall generally be encouraged to minimize the number of new cul-de-sacs to be maintained by the Township and to facilitate easy access to and from homes in different parts of the tract (and on adjoining parcels),
d. A tentative network of trails shall also be shown, connecting streets with various natural and cultural features in the conserved Greenspace lands. Potential trail connections to adjacent parcels shall also be shown, in areas where a township trail network is envisioned.
4. Step 4: Design of Lot Lines
Lot lines for the subdivision should be drawn as the last step in the design procedure. They should follow the configuration of house sites and streets in a logical and flexible manner.
A. Prioritized List of Resources to be Conserved.
The design of Greenspace lands in any subdivision or land development plan shall reflect the standards set forth in Section 601-A and, to the fullest extent possible, incorporate any of the following resources if they occur on the tract (listed in order of significance):
1. Areas where precipitation is most likely to recharge local groundwater resources because of topographic and soil conditions affording high rates of infiltration and percolation.
2. Stream channels, floodplains, wet soils, swales, springs and other lowland areas, including adjacent buffer areas which may be required to insure their protection.
3. Healthy woodlands, particularly those performing important ecological functions such as soil stabilization and protection of streams, wetlands and wildlife habitats.
4. Significant natural areas of species listed as endangered, threatened, or of special concern, such as those listed in the Pennsylvania Natural Diversity Inventory.
5. Class I, II and III agricultural soils as defined by the USDA Natural Resource Conservation Service.
6. Moderate to steep slopes, particularly those adjoining water courses and ponds, where disturbance and resulting soil erosion and sedimentation could be detrimental to water quality.
7. Visually prominent topographic features such as knolls, hilltops and ridges, and scenic viewsheds as seen from public roads (particularly those with historic features).
8. Historic structures and sites.
9. Hedgerows, groups of trees, large individual trees of botanic significance, and other vegetational features representing the site's rural past.
10. Existing trails connecting the tract to other locations in the Township.
B. Other Design Considerations.
The configuration of proposed Greenspace Lands set aside for common use in residential subdivisions shall comply with the following standards:
1. They shall be free of all structures except historic buildings, stone walls, and structures related to Greenspace uses. The Board may grant approval of structures and improvements required for storm drainage, sewage treatment and water supply within the Greenspace provided that such facilities would not be detrimental to the Greenspace (and that the acreage of lands required for such uses is not credited towards minimum Greenspace acreage requirements for the tract, unless the land they occupy is appropriate for passive recreational use).
2. They shall generally not include parcels smaller than three acres, have a length-to-width ratio of less than 4: 1, or be less than 75 feet in width, except for such lands specifically designed as neighborhood greens, playing fields or trail links.
3. They shall be directly accessible to the largest practicable number of lots within the subdivision. Nonadjoining lots shall be provided with safe and convenient pedestrian access to Greenspace Land.
4. They shall be suitable for active recreational uses to the extent deemed necessary by the Board, without interfering with adjacent dwelling units, parking, driveways, and roads.
5. They shall be interconnected wherever possible to provide a continuous network of Greenspace Lands within and adjoining the subdivision.
6. They shall provide buffers to adjoining parks, preserves or other protected lands.
7. Except in those cases where part of the Greenspace is located within private houselots, they shall provide for pedestrian pathways for use by the residents of the subdivision. Consideration shall be given to providing for public access on such trails if they are linked to other publicly-accessible pathway systems within the Township. Provisions should be made for access to the Greenspace Lands, as required for land management and emergency purposes.
8. They shall be undivided by public or private streets, except where necessary for proper traffic circulation.
9. They shall be suitably landscaped either by retaining existing natural cover and wooded areas and/or according to a landscaping plan to protect Greenspace resources.
10. Greenspace Lands shall not be excavated or filled without an approved grading plan for such areas, which shall be submitted to the Board for its review and action.
11. They shall be made subject to such agreement with the Township and such conservation easements duly recorded in the office of the Chester County Recorder of Deeds as may be required by the Board for the purpose of preserving the common open space for such uses.
12. They shall be consistent with the Township's Comprehensive Plan and its Open Space, Recreation, and Natural Resources Plan.
