The purposes of this article are as follows:
A. 
To promote the public health, safety and welfare by the protection of steep slope areas and by encouraging the retention of open space located and designed so as to constitute a harmonious and appropriate part of the physical development of Willistown Township.
B. 
To permit only those uses of steep slope areas which are compatible with the conservation of natural conditions and which maintain stable soil conditions by minimizing disturbances to vegetative ground covers and restricting the regrading of steep slope areas.
C. 
To limit soil erosion and the resultant destruction of the land, siltation of streams and damage to the property of individuals.
D. 
To protect low-lying areas from flooding by limiting the increase in stormwater runoff caused by grading of sloped areas, changes of ground cover or the erection of structures.
E. 
To maintain the ecological integrity and habitat value of steeply sloped areas, i.e., indigenous vegetation and wildlife, which could be adversely affected by otherwise permitted disturbances.
F. 
To allow the continuing replenishment of groundwater resources and the maintenance of springs.
A. 
Compliance. No area within the Steep Slope Conservation District shall hereafter be used without full compliance with the terms of this article, Chapter 139, Zoning, and other applicable regulations.
B. 
Steep Slope Conservation District overlay concept. The Steep Slope Conservation District shall be deemed an overlay on any zoning district(s) now or hereafter enacted to regulate the use of land in Willistown Township.
(1) 
The Steep Slope Conservation District shall have no effect on the permitted uses in the underlying zoning district, except where said uses are intended to be located within the boundaries of the Steep Slope Conservation District, as defined herein, and said uses are in conflict with the permitted uses set forth in this article. These regulations apply only to those portions of a tract or lot which come under the Steep Slope Conservation District; portions not under the district shall conform to the standards of the underlying zoning district.
(2) 
In those areas of the Township where the Steep Slope Conservation District applies, the requirements of the Steep Slope Conservation District shall supersede the requirements of the underlying zoning district(s).
(3) 
Should the Steep Slope Conservation District boundaries be changed as a result of legislative or administrative actions or judicial decision, the zoning requirements applicable to the area in question shall revert to the requirements of the underlying zoning district(s) without consideration of this article.
(4) 
For any parcel or any part thereof on which the Steep Slope Conservation District is an overlay, should the underlying zoning classification(s) be changed as a result of legislative or administrative actions or judicial decision, such change(s) in classification shall have no effect on the boundaries of the Steep Slope Conservation District, unless an amendment to said boundaries was included as part of the proceedings from which the subsequent change(s) originated.
C. 
Preservation of other restrictions. It is not intended by this article to repeal, abrogate or impair any existing easements, covenants or deed restrictions. However, where this article imposes greater restrictions, the provisions of this article shall prevail.
D. 
Municipal liability. Any determination that a proposed use complies with this chapter or any approval of a subdivision or land development plan or any issuance of a building permit within or near the Steep Slope Conservation District shall not constitute a representation, guaranty or warranty of any kind by the Township or by any official or employee thereof of the practicability or safety of the proposed use and shall create no liability upon the Township, its officials or employees. This chapter does not imply that areas outside the Steep Slope Conservation District boundaries or land uses permitted within said district will always be totally free from the adverse effects of erosion or other effects of nearby steep slopes.
A. 
The Steep Slope Conservation District consists of two areas which are delineated and defined as follows:
[Amended 3-13-2023 by Ord. No. 2-2023]
(1) 
Prohibitive slope. Prohibitive slopes are those of greater than 25% slope as based upon and mapped using two-foot contours from a topographic survey of the property or on the United States Geological Survey (USGS) Topographic Maps of the Regional Base Map Series of 1973 for the Malvern, Media, Valley Forge and West Chester Quadrangles (i.e., sloping more than 25 feet vertical over a distance of 100 feet horizontal), where such slope exists for five contiguous contour intervals in any continuous horizontal increment along the slope of 50 feet or more.
(2) 
Precautionary slope. Precautionary slopes are those of 15% to 25% slope as based upon and mapped using two-foot contours from a topographic survey of the property or on the USGS Topographic Maps of the Regional Base Map Series of 1973 for the Malvern, Media, Valley Forge and West Chester Quadrangles (i.e., sloping 15 feet to 25 feet vertical over a distance of 100 feet horizontal), where such slope exists for five contiguous contour intervals in any continuous horizontal increment along the slope of 50 feet or more.
B. 
Whenever there is a difference between the Zoning Map overlay and the two-foot contours from a property survey or the applicable United States Geological Survey Topographic Map, the two-foot contours from a site survey or Topographic Map shall determine the boundaries of the Steep Slope Conservation District.
[Amended 3-13-2023 by Ord. No. 2-2023]
C. 
Boundary interpretation and appeals procedure.
(1) 
Each application for construction or land disturbance within the Steep Slope Conservation District shall be submitted in accordance with § 73-33A below. Any area of the Steep Slope Conservation District that falls within the subject lot or lots shall be interpolated and shown on the site plan required under § 73-33A(1) through shading of such area or areas. The site plan shall contain a certification by the registered professional engineer or surveyor having prepared the plan as to the accuracy of the slopes as depicted on the plan. Areas shown as less than 10% slope may be based on United States Geological Survey information. Any area shown as 10% to 25% shall be delineated on the basis of an actual topographic survey of the site where those areas are proposed for disturbance.
[Amended 3-13-2023 by Ord. No. 2-2023]
(2) 
Where the exact location of the boundaries of the district in relation to a given parcel is in question, the applicant's site plan may be supplemented by a topographic survey of the property and any other documentation deemed pertinent. The Township Engineer shall evaluate all such material submitted and shall make a written report of the results of his determination, a copy of which shall be provided to the Board of Supervisors.
(3) 
Any party aggrieved by any such determination of the Township Engineer or other decision or determination under this section may appeal to the Zoning Hearing Board. The party contesting the location of the district boundary shall have the burden of proof in case of any such appeal.
A. 
Standards applicable to all uses within the Steep Slope Conservation District.
(1) 
All grading shall be minimized, and no grading shall be undertaken within any area of the Steep Slope Conservation District except where approved in conjunction with a use permitted under the terms of this article.
(2) 
Finished slopes of all cuts and fills shall not exceed 33% unless the applicant can demonstrate that steeper slopes can be stabilized and maintained adequately. Where standard grading is undertaken, the use of retaining walls shall be minimized. Where grades require a retaining wall, design plans indicating the need for the wall, its height and its impact upon the landscape shall be submitted for review by the Township Engineer.
(3) 
On any lot containing an area or areas of prohibited or precautionary slope, the total amount of impervious surface that may be installed or maintained within the total area or areas of such slope shall not exceed 50% of the maximum amount of impervious surface permitted for such use on any lot in the underlying base zoning district. Provision shall be made and approved by the Township Engineer for control of runoff from impervious surfaces to prevent erosion.
B. 
Uses permitted in areas of prohibitive slope. The following are the only uses permitted as of right in areas of prohibitive slope, provided that they also are in compliance with the base zoning district and all other provisions of this chapter and Chapter 139, Zoning:
(1) 
Parks and outdoor recreational uses, consistent with the goals of watershed protection.
(2) 
Logging and woodcutting, where such activity is limited to highly selective removal of trees. Maximum precautions shall be taken to avoid destruction of or injury to understory brush and trees.
(3) 
Grading for the minimum portion of a driveway necessary to access a single-family dwelling when it can be demonstrated that no other routing which avoids slopes exceeding 25% is feasible.
(4) 
Yard area of any permitted building, so long as such building is itself not within the prohibitive slope area, unless permitted as a conditional use.
C. 
Uses permitted in areas of precautionary slope. The following are the only uses permitted as of right in areas of precautionary slope, provided that they also are in compliance with the base zoning district and all other provisions of this chapter and Chapter 139, Zoning:
(1) 
Parks and outdoor recreational uses, consistent with the goals of watershed protection.
(2) 
Tree farming, forestry and other agricultural uses when conducted in conformity with conservation practices, including minimum tillage methods, approved by the Soil Conservation Service or the Chester County Conservation District.
(3) 
Access roads for the passage of emergency vehicles.
(4) 
Accessory uses (excepting swimming pools) necessary for the operation and maintenance of the above-permitted uses.
(5) 
Yard area of any permitted building.
D. 
Conditional uses in areas of prohibitive and precautionary slope. The following uses shall be permitted in areas of prohibitive and precautionary slope as a conditional use when authorized by the Board of Supervisors, subject to the requirements of this section and § 139-118.1 of Chapter 139, Zoning, of this Code. In making its determination, the Board shall give particular consideration to the criteria and standards in § 73-33B below.
(1) 
Any structure permitted by right, special exception or conditional use according to the terms of the underlying base zoning district.
(2) 
Any road necessary to provide primary access to a use permitted by Chapter 139, Zoning, when no practical alternative exists in an area of lesser slope. Any such road shall be constructed according to the standards of Chapter 123, Subdivision and Land Development.
(3) 
Sealed public water supply wells, where approved by all regulatory agencies.
(4) 
Sanitary or storm sewers, where approved by all regulatory agencies.
(5) 
Extractive uses, including borrow pits, within areas of precautionary slope only, when operated in accordance with recognized conservation practices and, as applicable, where approved by all regulatory agencies.
Administration of this section is governed by Article XIX, Administration, of Chapter 139, Zoning. In addition, the following requirements shall apply:
A. 
Application procedures.
(1) 
Before a permit is issued for any construction or land disturbance activity on land within or affecting the Steep Slope Conservation District, the following material, in full or in pertinent parts, shall be submitted for review by the Township Engineer:
(a) 
An earthmoving plan of the property which indicates existing grades, with contour lines for any area designated for disturbance at two-foot intervals for existing slope up to and including twenty-five-percent grade and five-foot intervals for existing slope above 25%. Proposed grades within the area of any proposed activity, disturbance or construction also shall be shown. All areas within the Steep Slope Conservation District shall be shaded accordingly.
(b) 
A site plan indicating existing and proposed structures, other impervious surfaces, storm drainage facilities and retaining walls. The site plan also shall locate and identify existing vegetation and ground cover within areas of prohibitive and precautionary slopes, as well as proposed landscaping material to be installed.
(c) 
Architectural plans, elevations and sections.
(d) 
A statement, signed and sealed by a registered architect or engineer, explaining the building methods to be used in overcoming foundation and other structural problems created by slope conditions, preserving the natural watersheds and preventing soil erosion and excessive surface water runoff to neighboring properties and/or streets.
(e) 
Plan, profile and typical cross sections of any proposed street, emergency access or driveway, with the seal of a registered professional engineer thereon.
(f) 
A statement, signed by the owner or future occupant at the time of subdivision, land development or building permit application, that there is a full understanding of any difficulties associated with access stemming from steep slopes.
(2) 
No approval or building permit shall be authorized by the Zoning Officer, and no conditional use shall be granted by the Board of Supervisors, without the Township Engineer's review of this material and his recommendation thereon.
B. 
Additional criteria for review of conditional uses. In evaluating any application for a conditional use, the Board of Supervisors shall evaluate the consistency of the proposal with the following criteria:
(1) 
Disturbance to particularly sensitive features of the site shall be minimized; special emphasis in planning for the site should be given to the protection of:
(a) 
The steepest areas of slope, i.e., those approaching and exceeding 25%.
(b) 
Soils with seasonal high water table.
(c) 
Underlying geology which comprises or contributes to a major groundwater resource, including the flow of existing springs.
(2) 
Disturbance shall be minimized where the length or area of prohibited or precautionary slope, both on the site and on adjacent lands within 200 feet of the site, is extensive.
(3) 
The proposed development, any impervious ground cover and the resultant disturbance to the land and existing vegetative cover will not cause runoff and/or related environmental problems off the site.
(4) 
Removal of or disturbance to existing vegetation on the site shall be minimized. The proposed impacts on existing vegetation shall be evaluated in terms of the potentially detrimental effects on slope stability, transpiration and recharge of stormwater, aesthetic and traditional characteristics of the landscape and existing drainage patterns. Mitigation measures may be required by the Board as it deems appropriate.
(5) 
Important visual qualities of the site shall, to the maximum extent feasible, be retained; in addition to vegetation, these may include hilltops or ridgelines, rock outcroppings and the natural terrain and contours of the site.
(6) 
Road construction shall follow the natural topography, with cuts and grading minimized.
(7) 
Innovative, imaginative building techniques that are well-suited to slope conditions shall be encouraged, consistent with other applicable codes and regulations.
(a) 
Every attempt shall be made to situate dwellings and accessory buildings below ridgeline elevations to preserve existing vistas. To achieve this objective, dwellings and accessory buildings should be sited entirely below the elevation of the nearest ridgeline, unless the applicant demonstrates that this is clearly infeasible.
(b) 
Where the applicant contends that the siting of dwellings entirely below ridgelines is infeasible, approval of his proposed siting shall be contingent upon the submission of individual lot landscaping plans and approval of those plans by the Board of Supervisors. Such plans shall identify the dimensions of each proposed dwelling, the architectural style proposed and the location of each dwelling and shall demonstrate how the dwelling will be effectively screened from adjacent tracts. Such siting shall comply in all other relevant respects with the provisions of this article and the underlying base zoning district.
(8) 
The equilibrium of the slope, as characterized by the existing interrelationships among the soil, water and vegetation, shall be disturbed as little as possible.
Following the adoption of this article, any use or structure which is situated within the boundaries of the Steep Slope Conservation District and which does not conform to the permitted uses specified in § 73-32 above shall become a nonconforming use or structure, regardless of its conformance to the district in which it is located without consideration of this article. The expansion or continuance of said nonconforming use or structure shall be governed by the requirements of §§ 139-90 and 139-91 of the Code of Willistown Township. However, the Zoning Hearing Board shall also ensure that the standards contained in § 73-33B above are applied to the expansion or continuance of said nonconforming use or structure.