[Ord. 1087, 10/17/2006]
This Part 3 shall be known and may be cited as the "Borough
of Mechanicsburg Sinkhole Ordinance."
[Ord. 1087, 10/17/2006]
Borough of Mechanicsburg topography may be defined as karst
due to the presence of carbonate rock that generally consists of dolomite
and limestone. The limestone and dolomite are divided into formations.
These formations are susceptible to the development of solution cavities
and sinkhole development. Anyone considering developing property or
conducting land disturbance activities within the Borough 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 those developments.
[Ord. 1087, 10/17/2006]
The regulations established by this Part 3 shall apply to all
zoning permits, building permits, land disturbance activities, land
development and/or subdivision applications pertaining to all uses,
(except those owned by Mechanicsburg Borough).
[Ord. 1087, 10/17/2006]
Minor land disturbance activities on a single lot existing on
the date of enactment of this Part 3 shall be exempt from the preparation
of a carbonate assessment report; however, such applications shall
be governed by the regulations established in this Part 3. This exemption
shall be subject to the submission of a letter of certification prepared
by a licensed professional that no visible features are present on
the land that would indicate a high risk of karst activity that would
negatively impact existing structures or proposed structures, roads,
utilities, and other features on the tract and within 100 feet of
the subject tract. If visible features are present, a carbonate assessment
report shall be submitted.
[Ord. 1087, 10/17/2006]
As used in this Part 3, 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 PA DEP or U.S. 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.
The use of land for activities in the following categories:
1) installation of new impervious or semi-impervious surface in excess
of 1,000 square feet; or 2) diversion or piping of any natural or
man-made watercourse; or 3) removal or disturbance of an area in excess
of 4,000 square feet for purposes of ground cover, grading, filling,
or other excavation, except for the agricultural use of land when
operated in accordance with a farm conservation plan approved by the
Cumberland County Conservation District.
A professional civil engineer with expertise in geotechnical
engineering or a professional geologist being licensed in their field
of expertise by the Commonwealth of Pennsylvania.
Aligned topographic features that locate faults and fractures.
The use of land involving:
The installation of new impervious or semi-impervious surface
between 1,000 and 4,000 square feet; or
Removal of ground cover, grading, filling or excavation between
4,000 square feet and one acre, except for the agricultural use of
land when operated in accordance with a farm conservation plan approved
by the Cumberland County Conservation District.
Soils derived from the in-place weathering of the underlying
bedrock.
Localized land surface subsidence or collapse due to karst
activity. 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 the land surface.
biological species or chemical compounds which are deemed
to be toxic or hazardous by the Pennsylvania Department of Environmental
Protection and United States Environmental Protection Agency.
[Ord. 1087, 10/17/2006]
1.
All of the following specific requirements shall apply to all permits, applications and activities described in § 26-303, Governance:
A.
No land disturbance activities shall be conducted and no buildings,
structures, road, utilities or stormwater conveyance or management
facilities shall be placed in or over sinkholes, closed depressions,
lineaments, or faults if unremediated in accordance with the terms
of this Part 3.
B.
No land disturbance activities shall be conducted and no buildings,
structures, roads, utilities, stormwater management basins and infiltration
facilities (where permitted) shall be located closer than 100 feet
from the rim of unremediated sinkholes, and no closer than 50 feet
from lineaments, faults, or closed depressions.
C.
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.
D.
Lagoons containing substances defined as toxic and/or hazardous by
the Pennsylvania Department of Environmental Protection are not permitted.
E.
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.
F.
The land application of hazardous materials is not permitted.
G.
The underground storage of any hazardous materials, except gasoline
and diesel fuel, shall be prohibited.
H.
Groundwater monitoring devices approved by the Borough are required
for all facilities handling hazardous materials.
2.
Borough Council shall not entertain requests for waivers from the
requirements listed above until a carbonate assessment report, as
required by this Part 3, has been supplied to the Planning Commission
and the Borough Engineer for their review and comment.
[Ord. 1087, 10/17/2006]
1.
All applications covered by this Part 3 shall be evaluated by a licensed
professional. A list of the licensed professional's qualifications
shall be submitted to the Borough prior to the commencement of the
site's evaluation. The Borough 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 Part 3. Further, the carbonate assessment
report submitted to the Borough must be signed and sealed by the preparing
licensed professional. The Borough may reject any report prepared
by a licensed professional whose qualifications have not been approved
by the Borough.
2.
The format and content of the carbonate assessment report shall include,
but not be limited to, the following:
A.
Statement of purpose. This section shall indicate those specific
sinkhole/carbonate regulations being addressed in the report and whether
the applicant is attempting to demonstrate compliance or justify noncompliance
with those specific sinkhole/carbonate regulations.
B.
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.
C.
A map, at a scale no smaller than one inch equals 100 feet and a
contour interval of two feet, indicating the location of the property
and all proposed improvements.
D.
Description and mapping information for on-site and adjacent properties
within 200 feet of the subject tract, 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.
E.
A recommended plan for the repair or remediation of surface or subsurface
features that may impact the proposed development or land disturbance
activity as well as the adjacent improved or unimproved properties
within 200 feet of the subject tract.
F.
The information requested above shall be based upon newly obtained
or previously published data and field surveys, which may include
test borings, excavation of test pits, air-track probes, and geophysical
methods.
G.
A plan indicating the existing and proposed drainage conditions,
locations of all proposed private sewage disposal and public sewerage
systems, and the location of existing private and public water supplies
on adjoining properties (within 100 feet of applicant's property).
H.
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.
I.
Proposed measures to control potential adverse environmental impacts
on groundwater quality and stormwater management resulting from the
land disturbance activities or the development and utilization of
the property.
J.
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.
3.
Stormwater Management.
A.
All regulated activities must include a stormwater management plan where required and prepared in accordance with Part 1 of this chapter limiting 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 buildings or structures for all uses, other than one single-family detached or one two-family detached dwelling, into storm drains by watertight gasketed joint conduits or adequately lined drainage swales and the collection of surface water flow on pavements into inlets connected to a watertight gasketed joint stormwater conduit or adequate lined drainage swales. The stormwater conduit must discharge into detention basins or designed infiltration areas.
B.
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 overexcavated a minimum of one foot and backfilled
with a compacted fine-grained soil.
C.
All detention basins in areas of sinkhole-prone soil shall be lined,
unless specifically identified as an infiltration recharge area. 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 follow the same standards as in Subsection 3B.
The Borough Engineer shall make the final determination as to what
is an acceptable form of liner for the proposed detention basins.
D.
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 inlets.
E.
Infiltration facilities will be permitted only where required by
PaDEP as part of the NPDES permit process for construction runoff
associated with construction activities. All infiltration facilities
shall be engineered by a licensed professional with experience in
the field of infiltration in karst areas.
[Ord. 1087, 10/17/2006]
1.
The carbonate assessment report must be received by the Borough when
a plan is submitted for permit application or at the time of preliminary
land development or subdivision approval and/or before any land disturbance
activities commence. The report may also be submitted at the time
of sketch plan review. Three copies of the report shall be submitted
to the Borough. The report shall be reviewed by the Borough Engineer
and other consultants as designated by the Borough. Based on the review,
the Borough may require additional information to be submitted if
the Borough concluded that such information would be instrumental
in assessing the proposed development as it relates to the sinkhole/carbonate
regulations.
2.
Approvals Required.
A.
Where compliance with this section is required before land disturbance
activities commence or as part of an application for subdivision or
land development approval, the Borough's decision on whether
compliance has been achieved shall be made as part of its review of
the land disturbance activities, permit, subdivision or land development
application.
B.
Where the application is part of a request for a building or zoning
permit, the Zoning/Code Officer shall not issue a permit until he/she
receives adequate written substantiation from the appropriate licensed
professionals that the terms of this Part 3 and any conditions imposed
upon the use of the property at the time of land disturbance activities,
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 Borough
shall attempt to make reasonable judgments as to the applicant's
compliance with the sinkhole/carbonate regulations. Under no circumstances
shall the Borough of Mechanicsburg or any officer or employee of the
Borough or consultant to the Borough assume any liability for any
damages that may result from an applicant's or any interested
party's reliance upon the regulations of the sinkhole/carbonate
regulations or any decisions made by the Borough in the administration
of such regulations by an applicant, developer, and/or any interested
party.
[Ord. 1087, 10/17/2006]
[Ord. 1087, 10/17/2006]
When there is or appears to be a violation of the provisions
of this Part 3, the Borough Zoning or Code Enforcement Officer or
his designated representative, in addition to any other remedies,
may institute in the name of the Borough any appropriate action at
law or in equity to prevent, restrain, correct or abate such violation.
[Ord. 1087, 10/17/2006]
Any person, including any association, partnership, corporation
or other entity, who shall violate any provision of this Part 3 or
shall fail to comply with any requirements thereof shall be guilty
of a summary offense and shall, upon conviction thereof, be sentenced
to pay a fine of not more than $1,000, plus costs of prosecution;
in default of payment of said fine and costs not caused by indigency,
said person may be subject to imprisonment of up to 30 days. Each
day that a violation exists shall constitute a separate offense. All
fines collected shall be paid over to the Borough.
