[Added 7-2-2002 by Ord. No. 4-02]
The standards for resource conservation, as set forth in this section, shall apply to all major subdivision and land developments in the Township. The standards for greenway delineation shall apply to all subdivision and land developments within the optional Conservation Design (CD-1) Overlay District.
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.
(1) 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 those provided for in other sections of this chapter dealing with groundwater conservation and replenishment.
(2) 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 plan as having the greatest permeability where precipitation is most likely to infiltrate and recharge the groundwater.
(3) The proposed subdivision and land development shall be designed in accordance with the general provisions of the Washington Township Wellhead Protection Plan.
C. Stream valleys, swales, springs, and other lowland areas. The Township's Comprehensive Plan describes and maps watercourses (which include stream channels and floodplains), wetlands, lakes, and other lowland areas as natural resource areas that warrant preservation and protection.
(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 and other lowland areas warrant designation as greenway lands. They may also require adjoining buffer lands to be included in the greenway, 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 greenway where it can be demonstrated that they are suitable for low-density residential uses and conventional on-site sewage systems.
D. Woodlands. 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.
(1) 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 groundwater recharge.
(b) As a means of ameliorating harsh microclimatic 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.
(2) 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 greenway or development lands. Evaluation criteria shall include:
(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.
(e) Relationship to woodlands on adjoining and nearby properties and the potential for maintaining continuous woodland areas.
(3) 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 Subsection
D(1) above.
(4) 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 greenway 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 lines 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 likely 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 greenway 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 nonprime 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 (15% to 25%) and steeply sloping lands (over 25%) 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 §
150-21 of the Zoning Ordinance and as required below.
(2) All grading and earthmoving on slopes exceeding 15% shall be minimized.
(3) No site disturbance shall be allowed on slopes exceeding 25% 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 25%, is feasible.
(4) On slopes of 15% to 25%, 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 15% 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 feet. 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. Significant natural areas and features. Natural areas containing rare or endangered plants and animals, as well as other features of natural significance, exist throughout the Township. Some of these features have been carefully documented, e.g., by the Pennsylvania Natural Diversity Inventory (PNDI), 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 Township's Comprehensive Plan or by the applicant's existing resources and site analysis plan (as required in §
119-10.1C) by incorporating them into proposed greenway areas or avoiding their disturbance in areas proposed for development.
H. Historic structures and sites. The Township's documented historical resources begin with the Seneca and Iroquois 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 the Pennsylvania Historical and Museum Commission, the Local Historical Society, and/or the Township.
(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 Township Council, a plan will have an impact upon an historic resource, the developer shall mitigate that impact to the satisfaction of the Township Council by modifying the design, relocating proposed lot lines, providing landscape buffers, or other approved means.
(2) Township participation, review and approval of the applicant's interaction with the State Historical and Museum Commission with regard to the preservation of historic resources, as required for DEP approval of proposed sewage disposal systems, shall be required prior to detailed final plan approval.
I. Historic rural road corridors and scenic viewsheds. Historic rural roads are located 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 greenway 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 specified 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.
J. Trails.
(1) When a subdivision or land development proposal is traversed by or abuts an existing trail customarily used by pedestrians and/or equestrians, the Township may require the applicant to make provisions for continued recreational use of the trail.
(2) The applicant may alter the course of the trail within the tract for which development is proposed under the following conditions:
(a) The points at which the trail enters and exits the tract remain unchanged.
(b) The proposed alteration exhibits quality trail design according to generally accepted principles of landscape architecture (for example: Bureau of State Parks publication "Non-Motorized Trails").
(c) The proposed alteration does not coincide with a paved road intended for use by motorized vehicles.
(3) When trails are intended for public or private use, they shall be protected by a permanent conservation easement on the properties on which they are located. The width of the protected area in which the trail is located should be a minimum of ten feet. The language of the conservation easement shall be to the satisfaction of the Township upon recommendation of the Township Solicitor.
(4) The land area permanently designated for trails for public use may be credited toward the greenway land requirement described in §
150-21E of the Zoning Ordinance.
(5) An applicant may propose and develop a new trail. If said trail is available for use by the general public and connects with an existing trail, the land area protected for said trail may be credited toward the open space requirement described in §
150-21E of the Zoning Ordinance.
(6) Trail improvements shall demonstrate adherence to principles of quality trail design.
(7) Trails shall have a vertical clearance of no less than 10 feet.
(8) Width of the trail surface may vary depending upon type of use to be accommodated, but in no case shall be less than three feet or greater than six feet.
(9) No trail shall be designed with the intent to accommodate motorized vehicles.