A.
Plan approval.
(1)
No change shall be made in the contour of land, no
earth-moving activity, including cut and fill, grading, excavation,
removal or destruction of the topsoil, trees or other vegetative cover
of the land, shall commence on any parcel except in strict conformance
with the West Deer Township Grading Ordinance[1] and no subdivision or land development plan shall be given
final plan approval until:
(a)
There has been a plan approved by the Pennsylvania
Department of Environmental Protection or the Allegheny County Conservation
District, or both, where required, that provides for temporary control
of erosion and sedimentation consistent with this section and acceptable
financial security is deposited with the Township which will ensure
installation and completion of the required improvements; or
(b)
There has been a determination by the Board
of Supervisors upon recommendation of the Township Engineer that a
plan for minimizing erosion and sedimentation is not necessary.
(2)
Where an erosion and sediment pollution control plan
has been filed and approved, the developer is solely responsible for
on-site pollution control measures.
B.
Stream channel construction on watersheds with drainage
areas in excess of 100 acres or in those cases where downstream hazards
exist shall conform to criteria administered by the Division of Dams
and Encroachments, Pennsylvania Department of Environmental Protection.
C.
The Township Engineer, or other official as designated,
shall ensure compliance with the appropriate erosion and sedimentation
control plans and specifications.
D.
Erosion and sedimentation controls.
(1)
The erosion and sedimentation plan shall be prepared in accordance with the Pennsylvania Erosion and Sedimentation Regulation (25 Pa. Code, Chapter 102) and the standards and specifications of the Allegheny County Conservation District.
(2)
The erosion and sedimentation control plan shall specifically
indicate all erosion and sedimentation control measures to be utilized
on the site. The plan shall meet the following requirements:
(a)
The erosion and sedimentation control plan shall
be prepared by persons trained and experienced in erosion and sedimentation
control methods and techniques.
(b)
The erosion and sedimentation control plan shall
be designed to prevent accelerated erosion and sedimentation and shall
consider all factors which contribute to erosion and sedimentation,
including but not limited to the following:
[1]
The topographic features of the project area.
[2]
The types, depth, slope and areal extent of
the soils.
[3]
The proposed alteration to the area.
[4]
The amount of runoff from the project area and
the upstream watershed area.
[5]
The staging of earthmoving activities.
[6]
Temporary control measures and facilities for
use during earthmoving.
[7]
Permanent control measures and facilities for
long-term protection.
[8]
A maintenance program for the control facilities,
including disposal of materials removed from the control facilities
or project area.
(3)
Proposed erosion/sedimentation control measures shall
be submitted with the stormwater management plan as part of the applicant's
preliminary and final plans.
(4)
The plan should show the type, location and application
of the proposed erosion/sedimentation control measures, and include
the calculations and criteria used in designing them.
(5)
Some of the guides to be followed in designing the
erosion/sedimentation control measures include the following:
(a)
The smallest practicable area of soil should
be exposed at any one time during construction, and exposure should
be limited to the shortest practicable period of time.
(b)
Temporary ditches, dikes, vegetation and/or
mulching shall be used to protect critical areas exposed during development.
(c)
Sediment basins (debris basins, desilting basins
or silt traps) shall be installed and maintained to remove sediment
from runoff waters from land undergoing development.
(d)
Wherever possible, temporary erosion/sedimentation
control measures should be designed to serve as part of a site's permanent
stormwater management control system.
(e)
Permanent vegetation and erosion control structures
should be installed as soon as practicable during construction activities.
(f)
Wherever feasible, natural vegetation should
be retained and protected and natural grade alterations kept to a
minimum.
The following activities shall be conducted
as outlined, except that earth disturbance activities related to agricultural
use shall be regulated by the Allegheny County Conservation District:
A.
Stripping of vegetation, grading or regrading, or
other earth disturbance shall be done only after review and approval
of an erosion and sedimentation plan by the Township Engineer and
all agencies with jurisdiction.
B.
Development plans shall preserve salient natural features,
keep cut-fill operations to a minimum and ensure conformity with existing
topography.
C.
Whenever feasible, natural vegetation shall be retained,
protected and supplemented.
D.
The maximum disturbed area and the duration of exposure
shall be in compliance with Pennsylvania Department of Environmental
Protection regulations.
E.
Disturbed soils shall be stabilized in compliance
with Pennsylvania Department of Environmental Protection regulations.
F.
The permanent (final) vegetation and structural erosion
control and drainage measures shall be installed as soon as practical
in the development.
G.
Provisions shall be made to effectively accommodate
the increased runoff caused by changed soil and surface conditions
during and after development. Where necessary, the volume of surface
water runoff generated after development shall be detained as per
an approved stormwater management plan.
In order to provide more suitable sites for
building and other uses, improve surface drainage and control erosion
and sediment pollution, the following requirements shall be met:
A.
All lots, tracts, or parcels shall be graded to provide
proper drainage away from buildings and dispose of the runoff without
ponding, and all land within a development shall be graded to drain
and dispose of surface water without ponding, except where other arrangements
are approved by the Township Engineer.
B.
All stormwater management facilities shall be of such
design to adequately handle the surface runoff and carry it to the
nearest suitable outlet such as a curbed street, storm drain or natural
watercourse. Where drainage swales are used to divert surface waters
away from buildings, they shall be sodded or planted or, where applicable,
rock-lined to reduce accelerated runoff, and shall be of such slope,
shape and size as to conform with the requirements of this section
and/or the standards of the Pennsylvania Department of Protection
Erosion and Sediment Pollution Control Program Manual.
C.
Concentration of surface water runoff shall be permitted
only in swales or detention ponds.
D.
Excavations and fills.
(2)
Adequate provisions shall be made to prevent surface
water from damaging the cut face of excavations or the sloping surface
of fills.
(3)
Cuts and fills shall be engineered so as to prevent
damage to adjoining property.
(4)
Fill shall be placed and compacted so as to minimize
sliding or erosion of the soil.
(5)
Fill shall not encroach on natural watercourses or
constructed diversion channels.
(6)
Fills placed adjacent to natural watercourses or constructed
channels shall have suitable protection against erosion during periods
of flooding.
E.
Grading shall not be done in such a way so as to divert
stormwater or fill onto the property of another landowner unless the
stormwater is being channeled into an existing natural drainage swale.
F.
During grading operations, necessary dust control
will be exercised.
G.
Topsoil shall be stockpiled only temporarily and be
preserved and redistributed as ground cover. Said topsoil shall be
expeditiously planted with perennial grasses or ground planting.
H.
Tree guards during construction and grading, and limitations
as to cuts and fills, both temporary and permanent near trees shall
be provided as necessary to give reasonable assurance of their continued
healthy growth.
I.
Grading equipment shall not cross live streams. Provision
shall be made for the installation of culverts or bridges.
A.
In connection with any subsurface-mined areas, a subsidence
risk assessment shall be provided by a geotechnical engineer with
experience and qualifications in mined land reclamation and licensed
by the Commonwealth of Pennsylvania. Should the geotechnical engineer
determine, in his or her assessment, that a geotechnical report is
required for the mined area(s), the report shall include:
(1)
A minimum of three core borings for the first five
acres and one additional boring for each additional five acres, with
borings uniformly spaced across the building site(s) unless otherwise
recommended by the geotechnical engineer.
(2)
An evaluation of the integrity, stability and nature
of the overburden.
(3)
An evaluation of the integrity, stability and nature
of the material used to fill the mine excavation.
(4)
An evaluation, based upon the above evaluations, of
the risk of subsidence associated with the area in its undeveloped
condition, and the increase in such risk that would be caused by the
proposed construction.
(5)
An identification of unsafe construction locations,
suitable construction sites and any measures and practices necessary
to minimize the risk of subsidence.
B.
In connection with any subsurface-mined areas, a subsidence
risk assessment shall be provided by a geotechnical engineer with
experience and qualifications in mined land reclamation and licensed
by the Commonwealth of Pennsylvania. Should the geotechnical engineer
determine, in his or her assessment, that a geotechnical report is
required for the mined area(s), the report shall include:
(1)
A minimum of three core borings for the first acre
and one additional boring for each additional acre of land proposed
for development unless otherwise recommended by the geotechnical engineer.
All borings shall be taken from proposed or potential construction
sites.
(2)
A map locating all known mine features within 300
feet of any proposed construction, whether such are located on or
off the development site. Such map shall identify the known limits
of the mine and any surface features caused by past mining activity,
such as mine waste dump areas, seepage areas and wetlands.
(3)
An identification of all environmental problems caused
by past mining activities, including, without limitation, subsidence,
acid runoff, residual ponding, disturbed drainage patterns, unstable
spoils piles or degraded water quality, that may affect the construction,
occupation or environmental integrity of the site.
C.
In addition to the subsidence risk assessment and/or
geotechnical investigation reports, the applicant shall submit with
his or her preliminary plan a description of the measures proposed
for eliminating or mitigating any risks or hazards associated with
past mining activities.
