[Ord. 689, 3/23/2016]
1.
No grading, stripping of topsoil, excavation, or any other land disturbance
activity which changes the existing contours of the land, and no clearing,
grubbing, or any other activity which results in the removal of existing
vegetation (other than the removal of dead or diseased plant material)
shall be permitted before the final grading permit has been approved.
2.
A soil erosion and sedimentation control plan shall be prepared in
accordance with the provisions of 25 Pa. Code, Chapter 102, "Erosion
Control."
3.
Grading shall be limited to the minimum area necessary to provide
for buildings, roads, parking areas, utilities, other facilities and
other work related to the grading.
4.
For slopes greater than 20% the applicant shall prepare a summary
of the records, if any, of the Pennsylvania Department of Environmental
Protection, Bureau of Mining and Reclamation, Division of Mine Subsidence
Insurance and Mine Subsidence Regulations, regarding the location,
depth and physical characteristics of any mine that underlies the
property or adjacent properties.
5.
The following requirements shall apply to all grading sites:
A.
All earth disturbance activities greater than 250 cubic yards require
a geotechnical report.
B.
The applicant shall be responsible to protect properties from any
damage which occurs as a result of the grading of his property. Such
protection shall include cleaning up and restoring to their original
condition any adjacent and downstream properties adversely affected
by silt, debris, flooding, or other damage resulting from the earth
disturbance activity.
C.
All topsoil shall be removed from the area to be graded and stockpiled
and preserved for possible reuse on the site.
D.
Fill areas shall be prepared by removing organic material, such as
vegetation and rubbish, and any other material determined by the administrator
to prevent proper compaction and stability.
E.
Proposed grading shall be accomplished so that existing stormwater
runoff flows are neither increased from predevelopment rates nor concentrated
at the point of release onto abutting properties. A stormwater management
report must be provided in accordance with the Township's stormwater
management ordinance.[1]
6.
No grading, removal of vegetation, construction, or other disturbance
shall be permitted on soils that are classified per the latest edition
of the Soil Survey of Allegheny County (USDA – Soil Conservation
Service) as landslide-prone or where mapping or other evidence exists
that indicates the land is subject to subsidence from mining activities,
or on any other areas of a site that exhibit signs of instability,
except in accordance with the provisions of the following:
A.
Unstable areas of a site may be set aside as common or private open
space.
B.
Limited disturbance of unstable areas may be allowed if the applicant
demonstrates to the satisfaction of the administrator that the proposed
disturbance will not cause sliding, movement, or any unsafe condition
either on the site or on any adjacent property.
C.
Evidence of the safety of any proposed disturbance shall require
site investigation and certification, in writing, by a registered
professional soils engineer, engineering geologist, or professional
engineer with experience in soils engineering that the proposed activity
will not create or exacerbate unsafe conditions.
[Ord. 689, 3/23/2016]
1.
To minimize the potential for erosion and landslide, maximum slope
steepness for cut and fill slopes shall be generally limited to:
A.
Cut and fill slopes up to 2 1/2 horizontal to one vertical will be permitted up to a maximum aggregate height of 30 feet. A ten-foot (minimum) vegetated bench with a negative slope of 20:1 toward the cut/fill must be provided before additional slope height would be permitted. A detailed geotechnical report, as described in § 9-129, is required.
B.
Cut and fill slopes up to two horizontal to one vertical will be permitted up to a maximum aggregate height of 20 feet. A ten-foot (minimum) vegetated bench with a negative slope of 20:1 toward the cut/fill must be provided before additional slope height would be permitted. A detailed geotechnical report, as described in § 9-129, is required.
C.
Cut and fill slopes steeper than two horizontal to one vertical will
be permitted only where retaining walls designed and sealed by a registered
professional engineer, licensed by the Commonwealth of Pennsylvania,
are constructed to support the face of the slope.
2.
In the case of existing dwellings or structures on any abutting property,
a buffer area shall be provided and be comprised of a continuous line
of evergreen trees that will grow together when mature and that are
a minimum of six feet in height at the time of planting. The administrator
may accept alternative buffer areas where existing trees and/or existing
topography provides an adequate screen to meet the intent of the required
buffer area. None of the required planting shall encroach across any
property line. The new or existing buffer area shall adequately screen
the grading activities from the existing dwelling or structures on
any abutting properties and be acceptable to the administrator.
3.
Excavation adjacent to any footing, foundations or structure shall
not extend below the minimum angle of repose or natural slope of the
soil under the nearest point unless the footing, foundation or structure
is first underpinned or otherwise protected against settlement. Before
starting any excavation which may affect physically in any way an
adjoining property or structures, the permit holder shall give written
notification to each owner of adjoining property or structures not
less than 30 days before excavation is to be made, informing them
that excavating is planned. A copy of the notification shall be submitted
to the administrator. Adjoining properties and structures shall be
protected as provided in the Building Code and/or as required by the
administrator.
4.
The tops and bottom edges of cut or fill slopes shall be kept back
from property or right-of-way lines five feet plus 1/5 the height
of the cut or fill.
5.
The administrator may require that the fill be constructed with exposed
slopes less than or flatter than three horizontal to one vertical
if he finds that, under the particular conditions, such flatter slope
is necessary for stability and safety.
6.
Topsoil stripped from the site in preparation for earthmoving activities
shall be stockpiled and replaced on the site over graded, nondeveloped
areas at a minimum depth of four inches.
7.
To prevent soil erosion, provide adequate slope treatment and ground
cover as shall be approved by the administrator.
8.
Finish grading shall be completed between March 15 and October 15
so turf and ground cover can be established.
A.
All land, regardless of its slopes, from which structures or ground
cover has been removed, shall be graded to the approximate finished
surface and seeded within 30 days after each phase of the construction
activity is completed.
B.
For slopes steeper that three horizontal to one vertical, the ground
cover shall be an approved variety of erosion-resistant vegetation.
[Ord. 689, 3/23/2016]
1.
Maximum steepness of a fill slope or embankment shall be no greater
than two horizontal to one vertical.
2.
The site shall be prepared by cutting toe benches and other keyways
so as to provide a firm base on which to place the fill.
3.
The administrator may require that the fill be constructed with exposed
slopes less than or flatter than three horizontal to one vertical
if he finds that, under the particular conditions, such flatter slope
is necessary for stability and safety.
4.
Debris or waste shall not be considered as fill material.
5.
No rock or material in excess of 12 inches in any dimension shall
be buried in fills.
6.
No organic or frozen materials shall be placed in fills.
7.
No fill of any kind shall be placed over trees, stumps or other material
which would create a nuisance or be susceptible to attracting rodents,
termites or other pests.
8.
Benching of the existing surface shall be required and indicated
on the cross sections.
9.
A porous drain shall be installed on the bottom and back wall of
the toe bench, together with a drainpipe and suitable discharge pipe
to the existing nonerosive surface beyond and below the toe of the
proposed fill.
10.
At the end of each workday, the horizontal surface of the fill shall
be shaped, compacted and rolled to provide drainage.
11.
All fills shall be compacted to provide stability of material and
to prevent undesirable settlement. The fill (excepting rock) shall
be spread in a series of layers, each not exceeding 12 inches in thickness,
and shall be compacted by a sheepsfoot roller or other approved method
after each layer is spread. Fill shall be placed at the optimum moisture
content for the specified degree of compaction. The administrator
shall require tests or other information if, in his opinion, the conditions
of materials are such that additional information is needed. Where
fills are to have streets, structures or public utilities placed in
or on them, they shall be compacted to 95% of the determined dry weight
density of the material. The dry weight density shall be determined
by the Modified Proctor Compaction Test in accordance with ASTM Standard
Test Method D1557-02. The permittee shall submit to the Township certified
compaction test results performed by a soils testing laboratory contracted
by the permittee prior to release of the completion bond security.
[Ord. 689, 3/23/2016]
1.
All earth disturbance activities greater than 250 cubic yards require
a geotechnical report, including detailed on-site subsurface investigation,
prepared to the satisfaction of the administrator, signed and sealed
by a registered professional engineer, licensed in the Commonwealth
of Pennsylvania and experienced in geological sciences, certifying
that he has inspected the site, reviewed the subsurface investigation
data and that it is his professional opinion that the proposed slope
will have sufficient stability and construction and will not endanger
or result in injury to persons, adjacent property, utilities, streets,
alleys or structures or, when complete and stabilized, be subject
to accelerated erosion.
2.
The report shall include specific findings and recommendations, including,
but not limited to, core boring methods of construction, benching,
minimum compaction rates, surface and subsurface drainage and erosion
control measures.
3.
During construction, the geotechnical engineer shall be required
to conduct site inspections and conduct or observe compaction tests
to ensure that the construction is proceeding in accordance with his
recommendations and good engineering and construction practices.
4.
At the conclusion of construction, and prior to release of the bond
or financial security provided in connection with the permit, the
geotechnical engineer shall provide a written report, including compaction
test results, and a signed and sealed certification stating the he
has inspected the construction of the fill slope(s) and that it is
his professional opinion that the slope(s) was/were constructed in
accordance with his recommendations and sound engineering and construction
practices.
5.
A geotechnical report is not required for excavations of house foundations
unless they exceed the exemption specified in this chapter and the
house location is not in slide-prone soils.
6.
The applicant shall agree, in writing, to follow all the recommendations
and designs of the geotechnical engineer.
7.
The Township may, at its sole option, hire its own geotechnical engineer
at the applicant's expense to review the engineering design,
grading and construction plans and specifications of the applicant's
geotechnical engineer to determine their compliance with the requirements
of this chapter. The Township shall determine the amount of the escrow
account to be established for purposes of compensating its geotechnical
engineer.
[Ord. 689, 3/23/2016]
1.
No grading work shall be started prior to approval and implementation of a stormwater management plan in conformance with Chapter 23, Stormwater Management.
A.
If the stormwater management report provides for infiltration, then
a geotechnical report must be provided that addresses the suitability
of the soils to allow for the infiltration and provide information
regarding field-measured infiltration rates.
B.
The report must address slope stability considering saturated conditions.
2.
Adequate provisions shall be made in accordance with sound engineering
practice to prevent surface water from damaging the cut face of excavations,
the face of fill and embankment slopes and/or adjacent properties.
Interceptor and diversion facilities for stormwater and surface water
runoff, both above and below the cut and fill slope areas, during
and after construction, shall be included in the design.
3.
The drainage pattern of the existing site conditions and proposed
construction shall be indicated on the plans. Measures according to
sound engineering practice shall be taken to prevent any erosion and
water runoff damage to adjacent properties during construction and
after completion of construction.
4.
Storm sewers, inlets, drainage ditches and swales necessary to protect
adjacent properties, and reduce erosion, whether temporary or permanent
in nature, shall be constructed before any excavation or filling is
started. The storm sewers, inlets, drainage ditches and swales shall
be maintained, cleaned, and kept open during and after construction.
If this requirement is not complied with, the administrator shall
stop all clearing, grubbing and grading on the site until the necessary
drainage facilities are completed.
5.
New storm sewers and utilities traversing a proposed fill area shall
have a minimum cover of three feet from the top of pipe to proposed
grade. Fill shall be constructed in that area prior to installation
of the new sewers and utilities. The minimum size storm sewer, exclusive
of toe or bench drains, shall be 15 inches in diameter, unless the
administrator approves a variation in size. The type of storm sewer
pipe to be located under pavement areas shall be approved by the administrator.
6.
Drainage ditches and swales with a grade of 5% or greater shall be
surfaced with concrete, hot bituminous material, brick, half pipe,
stone or other hard, nonerodible material or fabric material designed
and approved to prevent erosion for the proposed grades.
7.
Drainage ditches with a grade of less than 5% shall be lined with
grass using a fabric material and sloped in such a manner that they
can be conveniently cut and maintained.
8.
Constructed benches in the fills or cuts or at the top of slopes
shall have 2% reverse slopes and horizontal slopes perpendicular to
the flow of the bench of at least 2% for the purpose of carrying off
surface waters. If conditions warrant, the administrator shall require
a stabilized liner to be installed on any bench to prevent erosion.
9.
The planting of landscaping on slopes to reforest the slope and prevent
localized erosion shall be required. When requested by the administrator,
a landscaping plan shall be submitted for review and approval by the
administrator.
10.
Drainage structures, storm sewers, detention ponds, sedimentation
ponds and appurtenances shall be designed and constructed according
to sound engineering practice to discharge surface and subsurface
water to the nearest existing storm drain or natural watercourse approved
by the administrator or his authorized representative. Approval by
the administrator does not relieve the owner of his legal responsibilities
to adjacent property owners. The owner shall also comply with all
state laws and regulations dealing with enclosing or discharging stormwater
runoff into existing streams, channels or storm sewers.
11.
Storm sewers, inlets, drainage ditches and swales necessary to prevent
illicit discharges into the Township's separate storm sewer system
(MS4), whether temporary or permanent in nature, shall be constructed
before any excavation or filling is started. The storm sewers, inlets,
drainage ditches and swales shall be maintained, cleaned, and kept
open during and after construction. If this requirement is not complied
with, the administrator shall stop all clearing, grubbing and grading
on the site until the necessary drainage facilities are completed.
12.
The grading plan shall follow vegetative control methods and ditch
conduit control methods as specified in the current Department of
Environmental Protection Erosion and Sediment Control Manual.
13.
The one-hundred-year storm shall be used to design all permanent
storm sewers and drainage facilities. The twenty-five-year storm shall
be used to design all temporary storm sewers and drainage facilities.
14.
No rock fill shall be placed around or over storm sewers or drainage
facilities other than that designed as part of the site drainage facilities.
[Ord. 689, 3/23/2016]
In order to prevent erosion, the permittee shall be required
to provide adequate surface treatment by installing ground cover of
such kind and character as may be approved by the administrator. The
applicant shall submit a soil erosion and sedimentation control plan
and post-construction stormwater management plan for review and approval
of the administrator prior to the commencement of any grading or other
regulated earth disturbance activity. The plan shall be prepared in
accordance with the provisions of 25 Pa. Code, Chapter 102, "Erosion
Control." The administrator may require that the applicant's
plan also be approved by the Allegheny County Conservation District
(ACCD), the Pennsylvania Department of Environmental Protection (DEP),
or the Army Corps of Engineers. If an NPDES permit is required, documentation
of the permit issuance must be provided.
[Ord. 689, 3/23/2016]
1.
The regulations in this section are intended to promote the public
health, safety and welfare by ensuring that watercourses and wetlands
will be preserved in their natural condition so that they may continue
to convey and store water, provide habitat for flora and fauna, and
serve as recreational and aesthetic resources.
2.
No grading, cutting, filling, removal of vegetation or other disturbance
of land shall be permitted within the required setback.
A.
The minimum setback for watercourses shall be 50 feet, measured from
the top of the channel bank.
B.
The setback for wetlands shall be as follows:
(1)
Wetlands one acre and larger shall have a fifty-foot setback
average depth.
(2)
Distribution of the required setback area shall be either:
(a)
At the uniform setback depth from the delineated edge of the
wetland; or
(b)
At a variable setback depth, based on a wetland management plan
prepared by a certified professional wetlands biologist. In no case
shall the setback be less than 10 feet from the delineated edge of
a wetland less than one acre or 20 feet from the delineated edge of
a wetland one acre or greater.
(3)
Minor grading and construction within the area of the required
setback or easement, required for development in other areas of the
site, may be allowed in accordance with all regulations of the DEP
and the Township.
C.
When a proposed grading plan encompasses or adjoins a watercourse
or wetland, the design of the proposed grading shall not alter site
drainage in ways that will reduce the ability of the watercourse or
wetland to support the vegetation and animal life that characterized
the area before grading. Existing wetlands may be used to control
stormwater runoff flows from a grading site, provided a certified
wetlands biologist participates in the design of the proposed stormwater
detention facility or certifies that the proposed facility will not
adversely affect the wetlands.
[Ord. 689, 3/23/2016]
Grading equipment shall not cross streams without approved protection.
Permits shall be obtained from the Pennsylvania Department of Environmental
Protection for temporary and permanent encroachment, relocations,
enclosures and temporary crossings of streams.
[Ord. 689, 3/23/2016]
No grading shall be permitted within 20 feet of designated or
known floodplains unless a permit is obtained from the appropriate
DEP office. Grading shall conform to the requirements and standards
of Title 25 of the Pennsylvania Code, Chapter 105, Environmental Resources,
Dam Safety and Waterways Management, and Title 25 of the Pennsylvania
Code, Chapter 106, Flood Plain Management.
[Ord. 689, 3/23/2016]
1.
Retaining walls shall be designed and constructed in accordance with
sound engineering practices and the current edition of the International
Building Code (IBC). The design for construction of a proposed retaining
wall shall be included in the application for a grading permit and
shall meet the requirements for approval and inspection.
2.
An engineer shall design the retaining wall and the plans submitted
for approval shall bear his seal and signature on walls exceeding
four feet in height.
3.
All walls on commercial property exceeding four feet in height, and
within 10 feet of a walking or driving surface, shall require safety
fencing along the top of the retaining wall. The safety fencing, not
more than 60% solid, shall be at least four feet but not more than
six feet in height. The retaining wall and fence material shall be
compatible with the building architecture. All walls and fences shall
be maintained and, when necessary, repaired or replaced.
4.
A geotechnical report, as described in § 9-129, is required for all walls four feet in height and greater. The maximum aggregate height of a wall shall not exceed 20 feet. A ten-foot (minimum) vegetated bench with a negative slope of 20:1 toward the cut/fill must be provided before additional slope height would be permitted. A detailed geotechnical report, as described in § 9-129, is required.
5.
The backfilling of retaining walls and the construction of below-grade
drainage facilities shall be performed in accordance with sound engineering
practice.
6.
Where a retaining wall is to be constructed, the vertical face of
the wall shall be at least two feet back from the adjoining property.
A.
This requirement may be waived by the administrator if it can be
satisfactorily demonstrated that an exception is necessary to ensure
reasonable use of the property and does not create a hazard.
B.
No portion of the retaining wall structure shall encroach upon adjacent
property. This requirement may also be waived when the proposed retaining
wall is a joint venture between adjacent property owners and the necessary
documents formalizing the joint venture are filed with the application
for the permit.
[Ord. 689, 3/23/2016]
Lot dry sumps:
1.
Provide limited stormwater management for a limited roof area.
2.
May be either an excavated pit filled with uniformly graded aggregate
wrapped in geotextile or a prefabricated storage chamber or pipe segment
that discharges stored runoff by infiltration into the surrounding
soil.
3.
The dry sump shall be designed, signed and sealed by a professional
engineer in accordance with the Pennsylvania Stormwater Best Management
Practices Manual.
4.
Typically, 18 inches to 48 inches of clean, washed, uniformly graded
aggregate with 40% void capacity (AASHTO No. 3 or similar) wrapped
in a nonwoven geotextile. At least 12 inches of soil shall be placed
over the dry sump.
5.
There shall be 10 feet of separation between the dry sump and building
foundations.
6.
Convey system overflows to downstream drainage systems.
7.
The design depth shall take into account frost depth to prevent frost
heave.
8.
Install during later stages of site construction to prevent sedimentation
and/or damage from construction activity.
9.
Excavate the dry sump bottom to a uniform, level, uncompacted subgrade
free from rocks and debris. Do NOT compact the subgrade.
10.
Completely wrap dry sump with nonwoven geotextile overlapping the
geotextile rolls by a minimum of 24 inches within the trench. Fold
back and secure excess geotextile during stone placement.
11.
Install continuously perforated pipe and other dry sump structures.
Connect the roof leaders to the structures.
12.
Place uniformly graded, clean, washed aggregate in six-inch lifts,
lightly compacting between lifts.
13.
Fold and secure nonwoven geotextile over trench, with minimum overlap
of 12 inches.
 Pennsylvania Stormwater Best Management Practices Manual
BMP 6.4.6 Dry Well/Seepage Pit 363-0300-002/December 30, 2006
|
14.
Dry sumps require regular and effective maintenance to ensure prolonged
functioning. The following represents minimum maintenance requirements
identified in the Pennsylvania Stormwater Best Management Practices
Manual for dry sumps:
A.
Inspect dry sumps at least four times a year, as well as after every
storm exceeding one inch.
B.
Dispose of sediment, debris/trash, and any other waste material removed
from a dry sump at suitable disposal/recycling sites and in compliance
with local, state, and federal waste regulations.
C.
Evaluate the drain-down time of the dry sump to ensure the maximum
time of 72 hours is not being exceeded. If drain-down times are exceeding
the maximum, drain the dry sump via pumping and clean out perforated
piping, if included. If slow drainage persists, the system may need
replacing.
D.
Regularly clean out gutters and ensure proper connections to facilitate
the effectiveness of the dry sump.
E.
Replace filter screen that intercepts roof runoff as necessary.
F.
If an intermediate sump box exists, clean it out at least once per
year.
[Ord. 689, 3/23/2016]
Discharges into the storm sewer system not composed entirely of stormwater, allowed by an NPDES permit or permitted by Chapter 23, Stormwater Management, are prohibited MS4 discharges. The administrator shall stop all clearing, grubbing and grading on the site until the necessary drainage facilities are completed to eliminate illicit discharges into the storm sewer system. The applicant shall be responsible, at his own cost, for cleaning the storm sewer system fouled by illicit discharges into the storm sewer system that are a result of the grading operation.
