[Added 7-21-2003 by Ord. No. 2003-339]
Palmer Township's topography may be defined
as a karst topography due to the presence of carbonate rock that generally
consists of dolomite and limestone. The limestone and dolomite are
divided into formations. The carbonate formations present in Palmer
Township consist of Epler, Rickenbach, Allentown, Jacksonburg and
Leithsville Formations. These formations are susceptible to the development
of solution cavities and sinkhole development. Therefore, anyone considering
developing property within the Township should be aware of the potential
geological hazards. The regulations contained herein are intended
to minimize the risk of sinkhole occurrence in areas of new development
and on lands adjacent to these developments.
The regulations established by this ordinance
shall apply to all land development or subdivision applications pertaining
to commercial, governmental (except those owned by Palmer Township)
and industrial/office structures, apartment complexes and multiple
single-family home developments with three or more lots.
All single-family homes and the alteration of
single-family homes to include detached structures such as garages,
barns and swimming pools shall be exempt from the regulations established
in this article.
As used in this article, the following terms
shall have the meanings indicated:
Rock types that are affected by dissolution weathering process
caused by slightly acidic groundwater. The most common types of rock
that are categorized as carbonate rock are limestone (calcium carbonate)
and dolomite (calcium magnesium carbonate).
Interconnected solution features within the bedrock surface.
Fine-grained soil that is used in the construction of a liner
that limits the rate of surface water intrusion into the subsurface.
A bowl-shaped depression in the land surface characterized
by internal drainage. A ghost lake is a closed depression which has
visible standing water after a heavy rainfall event.
A fracture in bedrock along which movement has taken place.
Materials that predominantly consist of silt and clay size
particles.
As defined and regulated by the PADEP or EPA.
A liner system that prohibits the infiltration of surface
water into the subsurface.
The terrain that results from the dissolution of carbonate
rock.
The dissolution of carbonate rock by slightly acidic groundwater.
Dissolution weathering, the removal of soluble materials from intact
carbonate rock by slightly acidic groundwater.
Aligned topographic features that locate faults and fractures.
Soils derived from the in-place weathering of the underlying
bedrock.
Localized land surface subsidence or collapse due to karst
processes. Sinkholes are categorized as solution sinkholes, collapse
sinkholes and subsidence sinkholes.
Where water flows naturally out of the bedrock or the overlying
soil mantle on to the land surface.
Biological species or chemical compounds which are deemed
to be toxic or hazardous by the Pennsylvania Department of Environmental
Protection.
A.
All of the following specific requirements shall apply
to land developments and/or subdivisions covered by this article:
(1)
No buildings, structures or stormwater management
basin shall be placed in or over the following features if unremediated
in accordance with the terms of this ordinance: sinkholes, closed
depressions, lineaments, or faults.
(2)
Building structures and stormwater management basins
shall be located no closer than 100 feet from the rim of unremediated
sinkholes, and no closer than 50 feet from lineaments, faults, or
closed depressions.
(3)
Outflow from a stormwater management basin and/or
post-development stormwater flows shall not be directed to any of
the following carbonate features: sinkholes, closed depressions, lineaments,
or caverns.
(4)
Lagoons containing substances defined as toxic and/or
hazardous by the Pennsylvania Department of Environmental Protection
are not permitted.
(5)
Storage and handling areas for hazardous materials
must have impermeable surfaces designed to contain materials stored/handled
and from which they shall be directed to a predetermined collection
point.
(6)
The land application of hazardous materials is not
permitted.
(7)
The underground storage of any hazardous materials,
except gasoline and diesel fuel, shall be prohibited.
(8)
Groundwater monitoring devices approved by the Township
are required for all facilities handling hazardous materials.
B.
The Township Board of Supervisors shall not entertain
requests for waivers from the requirements listed above until a Carbonate
Ordinance assessment report, as required by the ordinance, has been
supplied to the Planning Commission and the Township Engineer for
their review and comment.
A.
All land developments and/or subdivisions covered
by this article shall be evaluated by a licensed professional civil
engineer with expertise in geotechnical engineering or a licensed
professional geologist; each of said experts being licensed in their
field of expertise by the Commonwealth of Pennsylvania. A list of
the engineer's/geologist's qualifications shall be submitted to the
Township prior to the commencement of the site's evaluation. The Township
reserves the right to reject any report that in its opinion was authored
by an individual or firm which does not possess the background to
properly assess the site conditions as they relate to this ordinance.
Further, the Carbonate Ordinance assessment report submitted to the
Township must be signed by the licensed professional civil engineer
with expertise in geotechnical engineering and/or a licensed professional
geologist.
B.
The format and content of the Carbonate Ordinance
assessment report shall include, but not be limited to, the following:
(1)
Statement of purpose. This section shall indicate
those specific Carbonate Ordinance standards being addressed in the
report and whether the applicant is attempting to demonstrate compliance
or justify noncompliance with those specific Carbonate Ordinance standards.
(2)
Description of existing conditions. This section shall
present a description of existing characteristics of the property
with respect to geology, topography, ground and surface water hydrology,
soils, vegetation, and existing improvements and uses of property.
(3)
A map, at a scale no smaller than one inch = 100 feet
and a contour interval of two feet, indicating the location of the
property and all proposed improvements.
(4)
The developer/applicant shall submit information for
the affected properties, indicating the presence of any of the following
carbonate features: depressions, fissures, lineaments, faults, ghost
lakes, bedrock outcrops, sinkholes, seasonal high water levels, soil
mottling, springs, surface drainage entering the ground, disappearing
lakes or streams and caverns.
(5)
A recommended plan for the repair or remediation of
surface or subsurface features that may impact the proposed development
as well as the adjacent improved or unimproved properties.
(6)
The information requested above shall be based upon
previously published data and field surveys which may include test
borings, excavation of test pits, air-track probes, and geophysical
methods.
C.
In addition to the Carbonate Ordinance assessment
report, the developer shall also be required to provide the following
information:
(1)
A plan indicating the existing and proposed drainage
conditions, locations of all proposed private and public sewage disposal
systems, and the location of existing private and public water supplies
on adjoining properties (within 1,000 feet of applicant property).
(2)
Type, location and phasing of proposed site disturbance
and construction, as well as proposed future ownership, utilization
and maintenance of the property and the proposed improvements.
(3)
Proposed measures to control potential adverse environmental
impacts on groundwater quality and stormwater management resulting
from the development and utilization of the property.
(4)
Plans describing the design and construction of the
proposed stormwater management facilities proposed for the project.
A description of the minimum requirements are outlined below.
D.
Stormwater management.
(1)
All submissions for proposed developments must include
a stormwater management plan prepared in accordance with adopted regulations
and which limits surface water runoff and the intrusion of concentrated
flow of surface water into the subsurface. Facilities that are required
as part of the stormwater management plan include the collection of
all runoff from commercial, office and industrial building roofs into
storm drains by watertight gasketed joint conduits or adequately lined
drainage swales and the collection of surface water flow on pavements
into drop inlets connected to a watertight gasketed joint stormwater
conduit or adequate lined drainage swales. The stormwater conduit
must discharge into lined detention basins.
(2)
Approved stormwater conduits include HDPE, PVC, concrete,
steel and cast-iron pipe all with watertight rubber gaskets at each
joint. The use of corrugated metal pipe is not permitted. Construction
of the piping system must follow all other applicable ordinances.
Where rock is encountered at or above the planned conduit design grade,
the rock shall be undercut and over-excavated a minimum of one foot
and backfilled with a compacted fine-grained soil.
(3)
All detention basins in areas of sinkhole-prone soil shall be lined. The liner used in a detention basin may consist of a clay liner, a composite synthetic and soil liner or a synthetic liner. The type of liner required shall depend on the condition of the detention basin bottom and the probability of sinkhole occurrence resulting from the construction of the detention basin. The use of low-flow channel may also be required, depending on the duration and frequency of stormwater discharge into the detention basin. Subsurface detention systems must be in leakproof tanks or piping which follows the same standards as in Subsection D(2). The Township's Geotechnical Engineer shall make the final determination as to what is an acceptable form of liner for the proposed detention basins.
(4)
Additional items that must be included in the stormwater
management plan include details with regard to the sealing of all
pavement curbs and gutters, manholes and drop inlets.
A.
The Carbonate Ordinance assessment report must be
received by the Township when a plan is submitted for preliminary
land development or subdivision approval. However, the report may
be submitted at the time of sketch plan review. Four copies of the
report shall be submitted to the Township. The report shall be reviewed
by the Township Geotechnical Engineer and other consultants as designated
by the Township. Based on this review the Township may require additional
information to be submitted if the Township concludes that such information
would be instrumental in assessing the proposed development as it
relates to the Carbonate Ordinance.
B.
Approvals required.
(1)
Where compliance with this section is required as
part of an application for subdivision or land development approval,
the Township's decision on whether compliance has been achieved shall
be made as part of its review of the subdivision or land development
application.
(2)
Where the application is part of a request for a zoning
permit, the Zoning Officer shall issue no permit until he/she receives
adequate written substantiation from the appropriate designated experts
referred to above that the terms of this section and any conditions
imposed upon the use of the property at the time of subdivision or
land development approval are satisfied.
In carbonate areas, alteration and development
of land may be hazardous with respect to foundation safety of structures,
the creation of unstable land as a result of changes in drainage,
and the contamination of ground and surface waters. Within the limitations
of the information available at the time of the review of individual
applications, the Township shall attempt to make reasonable judgments
as to the applicant's compliance with the Carbonate Ordinance. Under
no circumstances shall the Township of Palmer or any officer or employee
of the Township or consultant to the Township assume any liability
for any damages that may result from an applicant's or any interested
party's reliance upon the regulations of the Carbonate Ordinance or
any decisions made by the Township in the administration of such regulations
by an applicant, developer, and/or any interested party.
