[Amended 9-29-2005 by Ord. No. 2005-12]
A. Purposes. The purposes of this section are to:
(1) 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 Caln Township.
(2) Permit only those uses of steep slope areas which
are compatible with the conservation of natural conditions and natural
vegetation and which maintain stable soil conditions by minimizing
disturbances to vegetative ground covers and by restricting the regrading
of steep slope areas.
(3) Limit soil erosion and the resultant destruction of
land, siltation of streams and damage to the property of individuals.
(4) 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.
(5) 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.
(6) Allow the continuing replenishment of groundwater
resources and the maintenance of springs.
B. Definitions. As used in this section, the following
terms shall have the meanings indicated below:
STEEP SLOPES
Those areas which have a range of slope of 15% or greater
but less than 20% in predevelopment condition.
VERY STEEP SLOPES
Those areas which have a range of slope 20% or greater in
predevelopment condition.
C. Rules for interpretation of steep slopes and very
steep slopes:
(1) The Steep Slope Overlay District is comprised of areas of steep slopes and very steep slopes, as shown on the map entitled "Topography Map of Caln Township" which is attached hereto and made a part of this chapter. Such map shall be referred to as the Steep Slope Overlay District Map. The Steep Slope Overlay District Map constitutes only a general representation of steep and very steep slopes, based on the analysis of the contours displayed on the United States Geological Survey (USGS) Quadrangles for Downingtown and Coatesville, Pennsylvania. As such, refined mapping will be required to more accurately define the district, as specified in §
155-36C(3) below.
(2) The Steep Slope Overlay District shall be considered
as an overlay to the Caln Township Zoning Map subject to the following:
(a)
The Steep Slope Overlay District shall have no effect on the permitted uses in the underlying zoning district, except to the extent provided for in §
155-36F.
(b)
Should the Steep Slope Overlay District boundaries
be revised as a result of 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
section.
(3) Interpretation of district boundaries.
(a)
The Steep Slope Overlay District Map shall be
used as a general guide for determining the boundaries of the district.
In any application for subdivision and/or land development, the applicant
shall, using two-foot contours, delineate steep slopes and very steep
slopes. Further, the applicant shall use an actual field topographic
survey as the source of contour information and the basis for depicting
such slope categories which shall be differentiated with separate
symbols and legend. However, these regulations shall only apply in
the following cases:
[1]
In the case of a subdivision and/or land development,
where two-foot contours shall be shown, the representative sample
of a steep slope or very steep slope shall be based on a cumulative
change in grade of six feet or more. Therefore, all steep slope and
very steep slope areas shall be shown, but only those occurring over
three consecutive contour intervals will invoke the use restrictions
herein.
(b)
Once delineated, the mapping submitted by the
applicant will be reviewed by the Township Engineer. The applicant
will be required to follow all regulations of this section for those
areas which reflect steep slope and very steep slope conditions as
determined through the Township Engineer's review.
D. Plan requirements for steep slopes. Where any site
has located on it the existence of steep slopes or very steep slopes,
the applicant shall supply the following information at the time of
application for subdivision and land development approval or a building
permit application:
(1) Subdivision or development plan application. The following
information shall be provided:
(a)
A site plan of the property indicating the existing
grades with contour lines at two-foot intervals and proposed grades
within the areas of the proposed construction.
(b)
A landscaping plan indicating proposed paved
areas, storm drainage facilities, retaining walls and ground cover,
together with trees and ornamental shrub locations.
(c)
A soil erosion and sedimentation control plan
showing how disturbed ground areas will be protected during construction
and how disturbed ground areas will be permanently stabilized. All
soil erosion and sedimentation control measures shall follow the requirements
of the Pennsylvania Department of Environmental Protection, Erosion
and Sedimentation Control Manual, latest edition.
(d)
A plan profile and typical cross sections of
the entrance drive and the proposed public street providing access
to such drive.
(e)
A plan for on-site sewage disposal facilities,
if connection to a public sanitary sewer system is not contemplated.
(2) Building permit application. In addition to the above
information, the following additional information shall be provided:
(a)
Architectural plans, elevations and sections
for all permitted buildings, structures or construction, accompanied
by a drainage plan and a soil erosion and sedimentation control plan.
(b)
A statement prepared, signed and sealed by a
registered architect or a licensed civil or structural engineer describing
in detail the building methods to be used in overcoming foundation
and other structural problems created by slope conditions, how the
natural slopes and watershed will be preserved substantially undisturbed,
the method proposed to prevent soil erosion, and details of how overland
stormwater runoff and groundwater will be diverted away from all building
areas below finished grade.
E. Limitation of construction on steep slopes. The construction,
erection and development of buildings or structures on steep slopes
shall be subject to the following limitations:
(1) The total amount of impervious surface that may be
installed or maintained shall not exceed 80% of the maximum amount
of impervious surface permitted in the underlying base zoning district.
(2) The allowable disturbance of all steep slopes on the
entire tract shall be a maximum of 75%.
F. Permitted uses on very steep slopes. The uses permitted
on very steep slopes shall be limited to the following:
(1) Open space reserved as part of a land development
so long as no more than 25% of the open space has a slope greater
than 25%.
(2) Wildlife sanctuary, woodland preserve, arboretum (exclusive
of buildings or structures) and recreation areas (exclusive of buildings
or structures).
(3) Tree farming, forestry and other agricultural uses
(exclusive of buildings or structures) when conducted according to
conservation measures approved by the Soil Conservation Service.
G. Restriction of construction and uses on very steep
slopes.
(1) That portion of any site, parcel or lot that is within
very steep slopes shall not be included in the calculation of net
lot area, with the following limitation: very steep slopes need not
be netted out in the calculation of net lot area if the minimum net
lot area (without reference to steep slopes) is increased to 133%
of the minimum lot size required by the underlying base zoning district
regulations.
(2) The total amount of impervious surface that may be installed or maintained shall not exceed 70% of the maximum amount of impervious surface permitted in the underlying base zoning district. The percent of maximum impervious coverage referred to above shall be calculated on the total lot area as increased in accordance with the requirements of Subsection
G(1) above.
(3) Unless permitted by special exception pursuant to Subsection
H below, or permitted by conditional use pursuant to Subsection
L below, there shall be no erection or construction of any building, structure, road, driveway, parking area or other similar structure or impervious surface on very steep slopes.
[Amended 8-9-2012 by Ord. No. 2012-03]
(4) The allowable disturbance of all very steep slopes
on the entire tract shall be a maximum of 50%.
H. Special exception uses on very steep slopes. The following uses shall be permitted on very steep slopes by special exception when authorized by the Zoning Hearing Board, subject to the requirements of this section. In addition to the criteria contained in §
155-171, the Zoning Hearing Board shall consider the extent to which the requested use will disrupt the stability of soils and natural vegetation and contribute to soil erosion before and after construction or installation of the permitted use. The Zoning Hearing Board shall attach such reasonable conditions as it determines necessary and reasonable in furthering the intent and purpose of this section. The uses which shall be permitted on very steep slopes by special exception shall be as follows:
(1) Sealed public water supply wells that have been approved
by all regulatory agencies having jurisdiction.
(2) Stormwater detention basins.
(3) Sanitary or storm sewers that have been approved by
all regulatory agencies having jurisdiction.
(4) Access roads suitable for passage or emergency vehicles
in the event of fire or accident. Such road shall be constructed only
when no viable alternative for emergency access exists, provided that
all requirements of applicable codes and ordinances are met, and subject
to approval by all regulatory authorities having jurisdiction.
(5) One primary road which is designed and intended to
serve as an access road to a subdivision or a driveway which is designated
and intended to serve as sole access to a lot therein, provided that
there is no other feasible way to design access to the property without
crossing very steep slopes. The criteria for construction of a public
or private street or driveway on very steep slopes is as follows:
(a)
Such street or driveway shall be proposed for
construction only when no viable alternative for access exists. The
burden shall be upon the applicant to show that no other alternative
exists.
(b)
The proposed road or driveway shall be placed
as close to the natural contour of the land in order to minimize cutting
and filling.
(c)
The construction standards and specifications of the proposed street(s) shall comply with the standards and specifications of §§
137-35 through
137-43 of Chapter
137 of the Caln Code (the Subdivision and Land Development Ordinance), and the construction standards and specifications of the proposed driveway(s) shall comply with the standards and specifications of the Caln Township Driveway Ordinance, Ordinance No. 2002-2, enacted on April 25, 2002.
(d)
The proposed street shall be designed to preclude
direct discharge of stormwater into a watercourse without natural
filtration provided by a filtration bed and/or detention basin sized
in accordance with accepted design criteria for stormwater management.
(e)
The construction of the proposed street or driveway
shall be preceded by the installation of the proposed storm drainage
and soil erosion and sedimentation control measures.
(f)
Criteria for compaction and stabilization of
cutting and filling areas shall be proposed by the applicant. Such
criteria shall be in accordance with acceptable engineering standards
and shall be subject to approval of the Township Engineer.
I. Nonconformities. If the imposition of the regulations set forth in this section results in any existing lot becoming nonconforming in terms of area requirements, such lot may not be subdivided but may be developed despite these regulations, provided that compliance is had with §
155-36D(1) and
(2),
E and
G(2) and
(4).
J. Standards for approval of development.
(1) The Board of Commissioners shall consider the following criteria before approving any uses on steep slopes and very steep slopes and the Zoning Hearing Board shall consider the following criteria before approving any of the uses which are permitted by special exception in Subsection
H of this §
155-36 on very steep slopes:
(a)
The degree of modification proposed within the
district to the topographic, soil and vegetation resources and the
techniques proposed to mitigate potential environmental impacts.
(b)
The effect the development would have on adjacent
properties.
(c)
The relationship of the proposed uses to the purposes in §
155-36A.
(2) The applicant shall provide evidence that:
(a)
The Steep Slope Overlay District is being proposed
for development since no other alternative location is feasible or
practical on the basis of access, topography or other physical design
considerations.
(b)
Earthmoving activities and vegetation removal
will be conducted only to the extent necessary to accommodate proposed
uses and structures and in a manner that will not cause excessive
surface water runoff, soil erosion, sedimentation and unstable soil
conditions. Further, it shall be demonstrated that any and all reasonable
mitigation techniques and procedures will be utilized or have been
considered in the preparation of the subdivision and/or land development
plan.
(c)
Proposed buildings and structures are of sound
engineering design, and footings are designed in response to the site's
slope, soil and bedrock characteristics and, where applicable, shall
extend to stable soil and/or bedrock.
K. Liability. Neither the approval nor the granting of
any construction permit, subdivision or land development approval
or site development plan involving any land governed by the provisions
of this section by an officer, employee or agency of the Township
or its officers, officials, employees or agencies shall create liability
upon or provide a cause of action against the Township, its officers,
agencies, agents or employees for any damage that may result pursuant
thereto.
L. Solar energy production facility. Notwithstanding any other limitation in this chapter, a solar energy production facility, along with its accessory uses, shall be permitted on steep and very steep slopes in the I Institutional District if approved by conditional use of the Board of Commissioners and compliance with the criteria set forth in §
155-98. Pruning and/or topping of trees located on the subject property so as to prevent shading of solar panels making up a solar energy production facility shall be permitted within the steep and very steep slopes of a solar energy production facility if approved as part of the conditional use application. In addition, an access road/driveway of a solar energy production facility shall be permitted within very steep slopes, provided that it is no more than 16 feet in width and the cumulative total length does not exceed 1,000 lineal feet.
[Added 8-9-2012 by Ord. No. 2012-03]