[Ord. 671, 3/6/1995, § 101]
1. Purpose. These regulations are adopted and implemented to achieve
the following general purposes and objectives:
A. To manage and control stormwater runoff resulting from land alteration
and disturbance activities in accordance with the watershed stormwater
management plans adopted pursuant to the Pennsylvania Stormwater Management
Act (Act 167 of 1978, as amended).
B. To utilize and preserve the desirable existing natural drainage systems
and to preserve the flood-carrying capacity of streams.
C. To encourage natural infiltration of rainfall to preserve groundwater
supplies and stream flows.
D. To provide for adequate maintenance of all permanent stormwater management
structures in the Township.
2. Applicability. The provisions of this Part shall apply to all subdivisions
and land development activity within the municipality of Elizabeth
Township.
3. Repealer. The Part shall repeal all other ordinances, or parts thereof,
which are contrary to or conflict with the provisions of this Part
to the extent necessary to give this Part full force and effect.
4. Severability. Should any Section or provision of this Part be declared
invalid by a court of competent jurisdiction, such decision shall
not affect the validity of this Part as a whole or any other part
hereof; the Parts or Sections remaining shall remain in effect as
if the part of the Section declared unconstitutional had never been
a part of this Part.
5. Liability Disclaimer.
A. Neither the granting of any approval under the stormwater management
provisions of this Part, nor the compliance with the provisions of
this Chapter, or with any condition imposed by a municipal official
hereunder, shall relieve any person from any responsibility for damage
to persons or property resulting therefrom, or as otherwise imposed
by law, nor impose any liability upon the Township for damage to persons
or property.
B. The granting of a permit which includes any stormwater management
facilities shall not constitute a representation, guarantee or warranty
of any kind by the Township, or by an official or employee thereof,
of the practicability or safety of any structure, use or other plan
proposed, and shall create no liability upon or cause of action against
such public body, official or employee for any damage that may result
pursuant thereto.
[Ord. 671, 3/6/1995, § 102]
1. Stormwater Management Performance Districts.
A. For purposes of stormwater management, the municipality of Elizabeth
Township is divided into the following stormwater management districts
as indicated on the district map for the watershed in which the Township
is located. One or more of these districts may be further subdivided
into subareas which have similar hydrological characteristics and
drain to a common point.
B. The location and boundaries of the watershed(s) and subareas are
shown on the designated Monongahela River Stormwater Management Watershed
Map, which is hereby adopted as part of this Section.
2. General Standards.
A. The following provisions shall be considered the overriding performance
standards against which all proposed stormwater control measures shall
be evaluated and shall apply throughout the municipality of Elizabeth
Township:
(1)
Any landowner and any person engaged in the alteration or development
of land which may affect stormwater runoff characteristics shall implement
such measures as are reasonably necessary to prevent injury to health,
safety or other property. Such measures shall include such actions
as are required:
(a)
To assure that the maximum rate of stormwater runoff is no greater
after development than prior to development activities; or controlled
at the release rate percentage as indicated on the designated Monongahela
River Stormwater Management Watershed Map.
(b)
To manage the quantity, velocity and direction of resulting
stormwater runoff in a manner which otherwise adequately protects
health and property from possible injury.
B. The stormwater management plan for the development site must consider
all the stormwater runoff flowing over the site.
C. No discharge of toxic materials shall be permitted into any stormwater
management system.
3. Watershed Standards; Designated Monongahela River Stormwater Management
Watershed.
A. The stormwater performance standards contained in this Section are
intended to implement the standards and criteria contained in the
designated Monongahela River Stormwater Management Watershed Plan,
adopted and approved in accordance with the Pennsylvania Stormwater
Management Act. If there is any discrepancy between the provisions
of this Section and the standards and criteria of the plan, or if
the watershed plan is subsequently amended, then the standards/-criteria
of the most current watershed plan shall govern.
B. Storm Frequencies. Stormwater management facilities on all development
sites shall control the peak stormwater discharge for the two, 10,
25 and 100 year storm frequencies. The SCS 24 hour, Type II Rainfall
Distribution shall be used for analyzing stormwater runoff for both
pre- and post-development conditions. The 24 hour total rainfall for
these storm frequencies in the watershed are:
|
Storm Frequency
|
Rainfall Depth
(inches)
|
---|
|
2 year
|
2.50
|
|
10 year
|
3.61
|
|
25 year
|
4.31
|
|
100 year
|
5.71
|
|
(For additional information or data on other storm return periods,
consult the "Rainfall Duration Frequency Tables of Pennsylvania,"
produced by PaDER, Office of Resource Management, Bureau of Dams and
Waterways Management, Division of Stormwater Management, Harrisburg,
February, 1983.)
|
C. Calculation Methods.
(1)
Development Sites. For the purpose of computing peak flow rates
and runoff hydrographs from development sites, calculations shall
be performed using one of the following: SCS publications, Technical
Release (TR) 55 or 20, HEC I or Penn State Runoff Model. The rational
formula may be used for small developments, see § 106(2).
(2)
Stormwater Collection/Conveyance Facilities. For the purposes
of designing storm sewers, open swales and other stormwater runoff
collection and conveyance facilities, any of the above calculation
methods or the Rational Method may be used. Rainfall intensities for
design should be obtained from the Pennsylvania Department of Transportation
rainfall charts.
(3)
Predevelopment Conditions. Predevelopment conditions shall be
assumed to be those which exist on any site at the time of adoption
of the designated Monongahela River Stormwater Management Watershed
Plan. Hydrologic conditions for all areas with pervious cover (i.e.,
fields, woods, lawn areas, pastures, cropland, etc.) shall be assumed
to be in "good" condition, and the lowest recommended SCS runoff curve
number (CN) shall be applied for all pervious land uses within the
respective range for each land use and hydrologic soil group.
(4)
Routing of hydrographs through detention/retention facilities
for the purpose of design of those facilities shall be accomplished
using the Modified-Puls Method or recognized reservoir routing method
subject to the approval of Elizabeth Township and Allegheny County.
D. Release Rate Percentage.
(1)
Definition. The release rate percentage defines the percentage
of the predevelopment peak rate of runoff that can be discharged from
an outfall on the site after development. It applies uniformly to
all land development or alterations within a subarea. The subareas
are delineated on the Township stormwater management district map.
(2)
Procedure for Use.
(a)
Identify the specific subarea in which the development site
is located from the watershed map and obtain the subarea release rate
percentage as indicated on the map.
(b)
Compute the pre- and post-development runoff hydrographs for
each stormwater outfall on the development site using an acceptable
calculation method for the two, 10, 25 and 100 year storms. Apply
no onsite detention for stormwater management but include any techniques
to minimize impervious surfaces and/or increase the time of concentration
for stormwater runoff flowing from the development site. If the post
development peak runoff rate and the runoff volume are less than or
equal to the predevelopment peak runoff rate and volume, then additional
stormwater control shall not be required at that outfall. If the post
development peak runoff rate and volume are greater than the predevelopment
peak runoff rate and volume, then stormwater detention will be required
and the capacity of the detention facility must be calculated in the
manner prescribed below.
(c)
Multiply the subarea release rate percentage by the predevelopment
rate of runoff from the development site to determine the maximum
allowable release rate from any detention facility for the four prescribed
storm events.
(d)
Design the outlet control facilities and size the volume of
the detention facility using the calculated post development hydrography
and accepted hydrography routing procedures in consideration of the
maximum allowable release rate.
E. No Harm Evaluation.
(1)
An applicant may seek to exceed the otherwise applicable subarea
release rate percentage by performing the "no harm evaluation." This
evaluation requires an independent engineering analysis to demonstrate
that other reasonable options exist to prevent the occurrence of increase
stormwater runoff discharge rates and/or velocities or that measures
can be provided to prevent increased stormwater discharge rates and/or
velocities from increasing flood elevations and accelerating erosion
at all downstream points in the watershed.
(2)
A "no harm evaluation" will be considered only in instances
where the discharge to a stream channel from the development occurs
directly to the Youghiogheny and Monongahela River, or through a properly
sized and designed regional stormwater detention facility.
(3)
The analysis for the no harm evaluation shall be submitted to
the Township Engineer and Allegheny Planning Department for review
and approval.
(4)
The "no harm evaluation" shall be prepared by a registered engineer
who is experienced in hydrology and hydraulics. The "no harm evaluation"
shall be completed using the following procedures:
(a)
The Penn State Runoff Model (PSRM)
is the hydrologic model required in this procedure. Use of this model
would produce results from a "no harm evaluation" analysis that could
be compared to the results of the watershed study.
1)
Develop the runoff hydrograph(s) for the design storms of the
site and areas tributary to it using the PSRM and the designated Monongahela
River Stormwater Management Watershed Plan and use of the development
for both predevelopment and postdevelopment conditions.
2)
Develop the runoff hydrograph(s) for the proposed site using
the PSRM. If no management or controls or proposed, this would be
equivalent to the runoff hydrograph under postdevelopment conditions.
If some management or controls are proposed, then the runoff hydrograph
under post development conditions would be modified to reflect their
effect on the rate, volume and timing of discharges.
3)
Subtract the runoff hydrograph ordinates under predevelopment
conditions (Step 1) from the discharge hyrdograph ordinates (Step
2), maintaining the time scales of both hydrographs for one-to-one
correspondence.
4)
Obtain the PSRM for existing conditions for the designated Monongahela
River Stormwater Management Watershed from the County.
5)
Locate the subbasin(s) in which the proposed development is
located and into which the discharge hydrograph enters. If more than
one subbasin receives this incremental flow, divide the flow accordingly.
6)
Add the incremental increase computed in Step 3 to the runoff
hydrograph for the subbasin(s) identified in Step 5.
7)
Route the adjusted runoff hydrograph through the Monongahela
River Watershed PSRM and note any increase in peak flows which would
occur in downstream subbasins. If no increase is noted, then the "no
harm" has been demonstrated. If no increase is observed in peak flows,
the increased potential for erosion and/or sedimentation in downstream
channels resulting from any change in the flood hydrograph predicted
by the model shall be evaluated. If no increased potential can be
demonstrated by appropriate technical means, then the "no harm" exemption
may be requested.
8)
If an increase in peak flow is observed in any of the downstream
subbasins or increased potential for erosion and/or sedimentation
is indicated, the "no harm" exemption shall not be granted.
[Ord. 671, 3/6/1995, § 103; as amended by Ord.
835, 6/4/2007, § 1]
1. General Criteria.
A. Applicants may select runoff control techniques, or a combination
of techniques, which are most suitable to control stormwater runoff
from the development site. All controls must be subject to approval
of the Township Engineer. The Township Engineer may request specific
information on design and/or operating features of the proposed stormwater
controls in order to determine their suitability and adequacy in terms
of the standards of this Part.
B. The applicant should consider the effect of the proposed stormwater
management techniques on any special soil conditions or geological
hazards which may exist on the development site. In the event such
conditions are identified on the site, the Township Engineer may require
in-depth studies by a competent geotechnical engineer. Not all stormwater
control methods may be advisable or allowable at a particular development
site.
C. The stormwater management practices to be used in developing a stormwater
management plan for a particular site shall be selected according
to the following order of preference:
(1)
Infiltration of runoff onsite.
(2)
Flow attenuation by use of open vegetated swales and natural
depressions.
(3)
Stormwater detention/retention structures.
D. Infiltration practices shall be used to the extent practicable to
reduce volume increases and promote groundwater recharge. A combination
of successive practices may be used to achieve the applicable minimum
control requirements. Justification shall be provided by the applicant
for rejecting each of the preferred practices based on actual site
conditions.
2. Criteria for Infiltration Systems.
A. Infiltration systems shall be sized and designed based upon local
soil and ground water conditions.
B. Infiltration systems greater than three feet deep shall be located
at least 10 feet from basement walls.
C. Infiltration systems shall not be used to handle runoff from commercial
or industrial working or parking areas. This prohibition does not
extend to roof areas which are demonstrated to be suitably protected
from the effects of the commercial/industrial activities.
D. Infiltration systems may not receive runoff until the entire drainage
area to the system has received final stabilization.
E. The stormwater infiltration facility design shall provide an overflow
system with measures to provide a nonerosive velocity of flow along
its length and at the outfall.
3. Criteria for Flow Attenuation Facilities.
A. If flow attenuation facilities are employed to assist in the control
of peak rates of discharge, their effects must be quantified using
the SCS Technical Release (TR) 55, Urban Hydrology for Small Watersheds
or other approved material. The effects of the flow attenuation facilities
on travel time should be reflected in the calculations.
B. Flow attenuation facilities such as swales and natural depressions
should be properly graded to ensure positive drainage and avoid prolonged
ponding of water.
C. Swales shall be properly vegetatively stabilized or otherwise lined
to prevent erosion.
D. Swales shall be designed according to the recommendations contained
in the Commonwealth of Pennsylvania, Erosion and Sediment Pollution
Control Program Manual.
4. Criteria for Stormwater Detention Facilities.
A. If detention facilities are utilized for the development site, the
facility(ies) shall be designed such that postdevelopment peak runoff
rates from the developed site are controlled to those rates defined
by the subarea release rate percentage for the two, 10, 25 and 100
year storm frequencies.
B. All detention facilities shall be equipped with outlet structures
to provide discharge control for the four designated storm frequencies.
Provisions shall also be made to safely pass, at minimum, the postdevelopment
100 year storm runoff without breaching or otherwise damaging (i.e.,
impairing the continued function of) the facilities. Should any stormwater
management facilities qualify as a dam under PaDER Chapter 105, the
facility shall be designed in accordance with those regulations and
meet the regulations concerning dam safety.
C. Shared storage facilities, which provide detention of runoff for
more than one development site within a single subarea, may be considered
and are encouraged. Such facilities shall meet the criteria contained
in this Section. In addition, runoff from the development sites involved
shall be conveyed to the facility in a manner that avoids adverse
impacts (such as flooding or erosion) to channels and properties located
between the development site and the shared storage facilities.
D. Where detention facilities will be utilized, multiple use facilities,
such as wetlands, lakes, ballfields or similar recreational/open space
uses are encouraged wherever feasible, subject to the approval of
the Township and Pennsylvania Department of Environmental Resources'
Chapter 105 regulations.
E. Other considerations which should be incorporated into the design
of the detention facilities include:
(1)
Inflow and outflow structures shall be designed and installed
to prevent erosion and bottoms of impoundment type structures should
be protected from soil erosion.
(2)
Control and removal of debris both in the storage structure
and in all inlet or outlet devices shall be a design consideration.
(3)
Inflow and outflow structures, pumping stations and other structures
shall be designed and protected to minimize safety hazards.
(4)
Fencing.
(a)
The water depth at the perimeter of a storage pond should be
limited to that which is safe for children. This is especially necessary
if bank slopes are steep or if ponds are full and recirculating in
dry periods. Restriction of access shall be provided in the form of
six-foot high vinyl fencing, dogear shadowbox type panels (Color Wicker)
manufactured veranda or approved equal (Panel Model No. 73020872 (six
feet by six feet), post kit Model 73002139, and Gate Model 73002471.
Installation shall be in strict accord with the manufacturer's
recommendations. The access gate shall be double width for eight-foot
opening for entry (located for easy access and maintenance). Unless
otherwise approved, the fence shall be placed along the outer perimeter
of the pond berm. The access to the facility shall be designed and
dimensioned to allow for entry by vehicular and maintenance equipment
(i.e., truck, backhoe, grass cutting, etc.).
(b)
The Board of Commissioners may consider an alternative fencing
material when requested by the developer if, in the opinion of the
Board, the fence location is suitable aesthetically or chain-link
fence as follows: six foot high galvanized chain-link fence (with
minimum No. 9 woven two-inch mesh, 2 3/8 inches O.D. line posts,
2 7/8 inches O.D. terminal posts, 1 1/4 inches O.D. top
and bottom rail, 1 3/4 inches O.D. gate frame) with eight-foot
access gates for entry (located for easy access and maintenance).
(5)
Side slope of storage ponds shall not exceed a ratio of 2:1
horizontal to vertical dimension on outside slope; 3:1 on interior
pond slopes.
(6)
Landscaping shall be provided for the facility which harmonizes
with the surrounding area.
(7)
Facility shall be located to facilitate maintenance, considering
the frequency and type of equipment that will be required.
5. Criteria for Collection/Conveyance Facilities.
A. All stormwater runoff collection or conveyance facilities, whether
storm sewers or other open or closed channels, shall be designed in
accordance with the following basic standards:
(1)
All sites shall be graded to provide drainage away from and
around the structure in order to prevent any potential flooding damage.
(2)
Lots located on the high side of streets shall extend roof and
French drains to the curb line storm sewer (if applicable). Low side
lots shall extend roof and French drains to a stormwater collection/conveyance/control
system or natural watercourse in accordance with the approved stormwater
management plan for the development site.
(3)
Collection/conveyance facilities should not be installed parallel
and close to the top or bottom of a major embankment to avoid the
possibility of failing or causing the embankment to fail.
(4)
All collection/conveyance facilities shall be designed to convey
the 25 year storm peak flow rate from the contributing drainage area
and to carry it to the nearest suitable outlet such as a stormwater
control facility, curbed street, storm sewer or natural watercourse.
(5)
Where drainage swales or open channels are used, they shall
be suitably lined to prevent erosion and designed to avoid excessive
velocities.
B. Wherever storm sewers are proposed to be utilized, they shall comply
with the following criteria:
(1)
Where practical, designed to traverse under seeded and planted
areas. If constructed within 10 feet of road paving, walks or other
surfaced areas, drains shall have a narrow trench and maximum compaction
of backfill to prevent settlement of the superimposed surface or development.
(2)
Preferably installed after excavating and filling in the area
to be traversed is completed, unless the drain is installed in the
original ground with a minimum of three feet cover and/or adequate
protection during the fill construction.
(3)
Designed (1) with cradle when traversing fill areas of indeterminate
stability, (2) with anchors when gradient exceeds 20 percent, and
(3) with encasement or special backfill requirements when traversing
under a paved area.
(4)
Designed to adequately handle the anticipated stormwater flow
and be economical to construct and maintain. The minimum pipe size
shall be 15 inches in diameter.
(5)
Drain pipe, trenching, bedding and backfilling requirements
shall conform to the requirements of the Township and/or applicable
PennDOT Specifications, Form 408.
(6)
All corrugated metal pipe shall be polymer coated, and with
asbestos bonding and paved inverts where prone to erode. Pipe within
a Township right-of-way shall be reinforced concrete pipe or smooth
interior polyethlene pipe with a minimum diameter of 15 inches.
(7)
Storm inlets and structures shall be designed to be adequate,
safe, self-cleaning and unobtrusive and consistent with municipal
standards.
(8)
Appropriate grates shall be designed for all catch basins, stormwater
inlets and other entrance appurtenances. All items shall conform to
the requirements of PennDOT specifications and/or Township requirements.
(9)
Manholes shall be designed so that the top shall be at finished
grade and sloped to conform to the slope of the finished grade. Top
castings of structures located in roads or parking areas shall be
machined or installed to preclude "rattling." All storm sewer lids
shall be labeled with the word "Storm."
(10)
Where proposed sewer connects with an existing storm sewer system,
the applicant shall demonstrate that sufficient capacity exists in
the downstream system to handle the additional flow.
(11)
Storm sewer outfalls shall be equipped with energy dissipation
devices to prevent erosion and conform with applicable requirements
of the Pennsylvania DER for stream encroachments (Chapter 105 of Pennsylvania
DER rules and regulations).
[Ord. 671, 3/6/1995, § 104]
1. Erosion/sedimentation plan shall be provided in accordance with the
Pennsylvania erosion/sedimentation regulations (25 Pa. Code, Chapter
102) and the standards and guidelines of the County Conservation District.
2. Proposed erosion/sedimentation measures shall be submitted with the
stormwater management plan as part of the preliminary and final applications.
[Ord. 671, 3/6/1995, § 105]
1. Maintenance Responsibilities.
A. The stormwater management plan for the development site shall contain
an operation and maintenance plan prepared by the developer and approved
by the Township Engineer. The operation and maintenance plan shall
outline required routine maintenance actions and schedules necessary
to insure proper operation of the facility(ies).
B. The stormwater management plan for the development site shall establish
responsibilities for the continuing operation and maintenance of all
proposed stormwater control facilities.
C. The Board of Supervisors shall make the final determination of the
continuing maintenance responsibilities prior to final approval of
the stormwater management plan. The Township reserves the right to
accept or reject the ownership and operating responsibility for any
or all of the stormwater management controls.
2. Maintenance Agreement for Privately Owned Stormwater Facilities.
A. Prior to final approval of the site's stormwater management
plan the property owner shall sign and record a maintenance agreement
covering all stormwater control facilities which are to be privately
owned. The agreement shall stipulate that:
(1)
The owner shall maintain all facilities in accordance with the
approved maintenance schedule and shall keep all facilities in a safe
and attractive manner.
(2)
The owner shall convey to the Township easements and or rights-of-way
to assure access for periodic inspections by the Township and maintenance,
if required.
(3)
The owner shall keep on file with the Township the name, address
and telephone number of the person or company responsible for maintenance
activities; in the event of a change, new information will be submitted
to the Township within 10 days of the change.
B. Other items may be included in the agreement where determined necessary
to guarantee the satisfactory maintenance of all facilities. The maintenance
agreement shall be subject to the review and approval of the Township
Solicitor.
[Ord. 671, 3/6/1995, § 106]
1. General Requirements. No final subdivision/land development plan
[shall] be approved, no permit authorizing construction issued, or
any earthmoving or land disturbance activity initiated until the final
stormwater management plan for the development site is approved in
accordance with the provisions of this Part.
2. Exemptions for Small Developments.
A. At the time of application the Township shall determine if the subdivision
development qualifies as a "small development" and, therefore, is
eligible for a simplified stormwater plan submission. For the purposes
of this Part, a small development is any subdivision or land development
which results in (or will result when fully constructed) the creation
of 5,000 or less square feet of impervious area and one acre or less
of any land cover change.
B. Applications for small developments shall include a plan which describes
the type and location of proposed onsite stormwater management techniques
or the proposed connection to an existing storm sewer system. The
plan should show accurately site boundaries, five foot interval contours,
locations of watershed and/or subarea boundaries on the site (if applicable)
and any watercourses, floodplains or existing drainage facilities
or structures located on the site. Contingent upon the approval of
the Township Engineer, alternative runoff computational techniques,
such as the Rational Method, may be used where applicable. The Township
reserves the right to require that the plan be prepared by a registered
professional engineer, surveyor or landscape architect.
C. The Township Engineer shall review and approve the proposed provisions
for stormwater management in accordance with the standards and requirements
of this Part.
3. Stormwater Plan Contents.
A. General Format. The stormwater plan shall be drawn at a scale of
not less than one inch equals 200 feet. All sheets shall contain a
title block with name and address of applicant and engineer, scale,
north arrow, legend and date of preparation.
B. Existing and Proposed Features. The plan shall show the following:
(1)
Watershed Location. Provide a key map showing the location of
the development site within the watershed(s) and watershed subarea(s).
On all site drawings, show the boundaries of the watershed(s) and
subarea(s) as they are located on the development site and identify
watershed name(s) and subarea number(s).
(2)
Floodplain Boundaries. Identify 100 year floodplains on the
development site (as appropriate) based on the municipal flood insurance
study maps.
(3)
Natural Features. Show all bodies of water (natural or artificial),
watercourses, (permanent and intermittent), swales, wetlands and other
natural drainage courses on the development site, or which will be
affected by runoff from the development.
(4)
Soils. Provide an overlay showing soil types and boundaries
within the development site (consult County, SCS and U.S. Geological
Survey for information).
(5)
Contours. Show existing and final contours at intervals of five
feet.
(6)
Land Cover. Show existing and final land cover classifications
as necessary to support and illustrate the runoff calculations performed.
(7)
Drainage Area Delineations. Show the boundaries of the drainage
areas employed in the runoff calculations performed.
(8)
Stormwater Management Controls. Show any existing stormwater
management or drainage controls and/or structures, such as sanitary
and storm sewers, swales, culverts, etc., which are located on the
development site, or which are located offsite but will be affected
by runoff from the development.
C. Professional Certification. The stormwater management plan (including
all calculations) must be prepared and sealed by a registered professional
engineer, surveyor or landscape architect with training and expertise
in hydrology and hydraulics. Documentation of qualifications may be
required by the Township.
D. Runoff Calculations. Calculations for determining pre and postdevelopment
discharge rates and for designing proposed stormwater control facilities
must be submitted with the stormwater management plan. All calculations
shall be prepared using the methods and data prescribed by § 102
of this Part.
E. Stormwater Controls. All proposed stormwater runoff control measures
must be shown on the plan including methods for collecting, conveying
and storing stormwater runoff onsite, which are to be used both during
and after construction. Erosion and sedimentation controls shall be
shown in accordance with applicable Township and County Conservation
District requirements. The plan shall provide information of the exact
type, location, sizing, design and construction of all proposed facilities
and relationship to the existing watershed drainage system.
(1)
If the development is to be constructed in stages, the applicant
must demonstrate that stormwater facilities will be installed to mange
stormwater runoff safely during each stage of development.
(2)
A schedule for the installation of all temporary and permanent
stormwater control measures and devices shall be submitted.
(3)
If appropriate, a justification should be submitted as to why
any preferred stormwater management techniques, as listed in § 103,
are not proposed for use.
F. Easements, Rights-of-Way, Deed Restrictions. All existing and proposed
easements and rights-of-way for drainage and/or access to stormwater
control facilities shall be shown and the proposed owner identified.
Show any areas subject to special deed restrictions relative to or
affecting stormwater management on the development site.
G. Other Permits/Approvals. A list of any approvals/permits relative
to stormwater management that will be required from other governmental
agencies (including DER Chapter 105 and 106 permits) and anticipated
dates of submission/receipt should be included with the stormwater
plan submission. Copies of permit applications may be requested by
the Township where they may be helpful for the plan review.
H. Maintenance Program. The application shall contain a proposed maintenance
plan for all stormwater control facilities in accordance with the
following:
(1)
Identify the proposed ownership entity (e.g. municipality, property
owner, private corporation, homeowner's association or other
entity).
(2)
Include a maintenance program for all facilities, outlining
the type of maintenance activities, probable frequencies, personnel
and equipment requirements and estimated annual maintenance costs.
(3)
Identify method of financing continuing operation and maintenance
if the facility is to be owned by other than the Township or governmental
agency.
(4)
Submit any legal agreements required to implement the maintenance
program and copies of the maintenance agreement as required by this
Part.
I. Financial Guarantees. Submit financial guarantees in accordance with
the provisions of this Part.
[Ord. 671, 3/6/1995, § 107]
1. Preapplication Phase.
A. Before submitting the stormwater plan, applicants are urged to consult
with the Township, County Planning Department and County Conservation
District on the requirements for safely managing from the development
site in a manner consistent with the Township ordinances and applicable
watershed stormwater management plan. These agencies may also be helpful
in providing necessary data for the stormwater management plan.
B. Applicants are encouraged to submit a sketch plan with a narrative
description of the proposed stormwater management controls for general
audience and discussion with the Township and other agencies.
C. The preapplication phase is not mandatory; any review comments provided
by the Township or other agencies are advisory only and do not constitute
any legally binding action on the part of the Township or any County
agency.
2. Stormwater Plan Review.
A. Submission of Plans. Stormwater plan applications shall be submitted
with the preliminary and final subdivision/land development applications.
B. Notification of Affected Municipalities. Copies of the plans will
be made available to upstream and downstream municipalities affected,
upon request. Comments received from any affected municipality will
be considered by the Township Engineer and County agencies in their
review.
C. County Planning Review.
(1)
A copy of the stormwater plan, along with all runoff calculations,
shall be forwarded to the Allegheny County Planning Department. A
report of the findings will be returned to the Township within 30
days.
(2)
If the Planning Department review identifies that the plan fails
to comply with the watershed standards and criteria or that a possibility
exists for harmful downstream impacts from the development site, the
applicant will be advised so that the necessary modifications can
be made to the stormwater management controls for the development
site. The Township Engineer shall not approve the development site's
stormwater management plan until modifications are made and the plan
receives a positive review from the County Planning Department.
D. Township Engineer's Review. The Township Engineer shall approve
or disapprove the stormwater management plan based on the requirements
of the Township ordinances, the standards and criteria of the watershed
plan and good engineering practice. The Engineer shall submit a written
report, along with supporting documentation, stating their reasons
for approval or disapproval.
E. Status of the Engineer's Determination. The approval/disapproval
of the site's stormwater management plan by the Township Engineer
shall be considered final. The Board of Supervisors shall not reverse
the Engineer's determination by approving or disapproving the
site's stormwater management plan or any specific control measure
in contradiction to the Engineer's action. The Board of Supervisors
may request information or alternative approaches to the stormwater
management controls, provided these are agreed to by the Township
Engineer and the applicant's engineer.
F. Permits Required From Other Governmental Agencies. Where the proposed
development requires an obstruction permit from the Pennsylvania DER
or an erosion/sedimentation permit from the County Conservation District,
then final stormwater management plan approval shall be conditional
upon receipt of such permits. However, no building permit shall be
issued, nor construction started, until the permits are received and
copies filed with the Township.
[Ord. 671, 3/6/1995, § 108]
1. Upon final stormwater plan approval and receipt of all necessary
permits, the applicant may commence to install or implement the approved
stormwater management controls.
2. If site development or building construction does not begin within
two years of the date of final approval of the stormwater management
plan, then before doing so, the applicant shall resubmit the stormwater
management plan to verify that no condition has changed within the
watershed that would affect the feasibility or effectiveness of the
previously approved stormwater management controls. Further, if for
any reason development activities are suspended for two years or more
then the same requirement for resubmission of the stormwater management
plan shall apply.
[Ord. 671, 3/6/1995, § 109]
1. If the request for a plan modification is initiated before construction
beings, the stormwater plan must be resubmitted and reviewed according
to the procedures contained in § 107 above.
2. If the request for a plan modification is initiated after construction
is underway, the Township Engineer shall have the authority to approve
or disapprove the modification based on field inspection provided:
(1) the requested changes in stormwater controls do not result in
any modifications to other approved Township land use/development
requirements (e.g., building setbacks, yards, etc.) and (2) the performance
standards in § 102 are met. Notification of the Engineer's
action shall be sent to the Board of Supervisors which may issue a
stay of the plan modification within five days and require the permittee
to resubmit the plan modification for full stormwater plan review
in accordance with § 107 above.
[Ord. 671, 3/6/1995, § 110]
1. If required due to the size of location of the stormwater control
facility the Township Engineer or a designated representative shall
inspect the construction of the temporary and permanent stormwater
management system for the development site. The permittee shall notify
the Engineer 48 hours in advance of the completion of the following
key development phases:
A. At the completion of preliminary site preparation, including stripping
of vegetation, stockpiling of topsoil and construction of temporary
stormwater management and erosion control facilities.
B. At the completion of rough grading but prior to placing topsoil,
permanent drainage or other site development improvements and ground
covers.
C. During construction of the permanent stormwater facilities at such
times as specified by the Township Engineer.
D. Completion of permanent stormwater management facilities including
established ground covers and plantings.
E. Completion of final grading, vegetative control measures or other
site restoration work done in accordance with the approved plan and
permit.
2. No work shall commence on any subsequent phase until the preceding
one has been inspected and approved. If there are deficiencies in
any phase, the Township Engineer shall issue a written description
of the required corrections and stipulate the time by which they must
be made.
3. If during construction the contractor or permittee identifies any
site condition, such as subsurface soil conditions, alterations in
surface or subsurface drainage which could affect the feasibility
of the approved stormwater facilities, he/she shall notify the Township
Engineer within 24 hours of the discovery of such condition and request
a field inspection. The Township Engineer shall determine if the condition
requires a stormwater plan modification.
4. In cases where stormwater facilities are to be installed in areas
of landslide-prone soils or other special site conditions exist, the
Township may require special precautions such as soil test and core
borings, full-time inspectors and/or similar measures. All costs of
any such measures shall be borne by the permittee.
5. All inspection cost as incurred from compliance with §§ 110(1)
through (4) shall be borne by the permittee.
[Ord. 671, 3/6/1995, § 111]
1. Guarantee of Completion. A completion guarantee in the form of a
bond, cash deposit, certified check or other negotiable securities
acceptable to the Township shall be filed. The guarantee shall cover
all streets, sanitary sewers, stormwater management facilities, water
systems, fire hydrants, sidewalks and other required improvements;
it shall be in the amount and from prescribed by the Municipalities
Planning Code, § 509.
2. Release of Completion Guarantee. The completion guarantee shall be
returned or released upon written certification by the Township Engineer,
or a designated agent, that improvements and facilities have been
installed and completed in accordance with the approved plan and specifications.
The procedures for requesting and obtaining a release of the completion
guarantee shall be in a manner prescribed by the Municipalities Planning
Code, § 510.
3. Default of Completion Guarantee. If improvements are not installed
in accordance with the approved final plan, the Board of Supervisors
may enforce any corporate bond or other security by appropriate legal
and equitable remedies. If proceeds of such bond or other security
are insufficient to pay the cost of installing or making repairs or
corrections to all the improvements covered by said security, the
Board of Supervisors may, at its option, install part of such improvements
in all or part of the development and may institute appropriate legal
or equitable action to recover the monies necessary to complete the
remainder of the improvements. All proceeds, whether resulting from
the security or from any legal or equitable action brought against
the developer, or both, shall be used solely for the installation
of the improvements covered by such security and not for any other
Township purpose.
4. Dedication of Public Improvements.
A. When street, sanitary sewers, stormwater management facilities, water
lines or other required improvements in the development have been
completed in accordance with the final approved plan, such improvements
shall be deemed private until such time as they have been offered
for dedication to the Township and accepted by separate ordinance
or resolution or until they have been condemned for use as a public
facility.
B. Prior to acceptance of any improvements or facilities, the Township
Engineer shall inspect it to ensure that it is constructed in accordance
with the approved plan and is functioning properly. In the case of
any stormwater control facility, it must be free of sediment and debris.
C. The owner shall submit as-built plans for all facilities proposed
for dedication.
5. Maintenance Guarantee. Prior to acceptance of any improvements or
facilities, the applicant shall provide a financial security to secure
the structural integrity and functioning of the improvements. The
security shall: (1) be in the form of a bond, cash, certified check
or other negotiable securities acceptable to the Township, (2) be
for a term of 18 months, and (3) be in an amount equal to 15 percent
of the actual cost of the improvements and facilities so dedicated.
[Ord. 671, 3/6/1995, § 112]
The Township may adopt by resolution, from time to time, a reasonable
schedule of fees to cover the cost of plan review, inspections and
other activities necessary to administer the provisions of this Part.
All fees shall be set in accordance with the applicable provisions
of the Municipalities Planning Code and any dispute over the fee amount
shall be resolved in the manner described by the Planning Code.
[Ord. 671, 3/6/1995, § 113]
1. Right of Entry. Upon presentation of proper credentials, duly authorized
representatives of the Township may enter at reasonable times upon
any property to investigate or ascertain the condition of the subject
property in regard to an aspect regulated by this Part.
2. Notification. In the event that the applicant, developer, owner or
his/her agent fails to comply with the requirements of this Part or
fails to conform to the requirements of any permit, a written notice
of violation shall be issued. Such notification shall set forth the
nature of the violation(s) and establish a time limit for correction
of the violation(s). Upon failure to comply within the time specified,
unless otherwise extended by the Township, the applicant, developer,
owner or his/her agent shall be subject to the enforcement remedies
of this Part.
3. Preventive Remedies.
A. In addition to other remedies, the Township may institute and maintain
appropriate actions by law or in equity to restrain, correct or abate
a violation, to prevent unlawful construction, to recover damages
and to prevent illegal occupancy of a building or premises.
B. In accordance with the Planning Code, § 515.1, the Township
may refuse to issue any permit or grant approval to further improve
or develop any property which has been developed in violation of this
Part.
4. Enforcement Remedies.
A. Any person who has violated or knowingly permitted the violation
of the provisions of this Part shall, upon being found liable therefore
in a civil enforcement proceeding commenced by the Township, pay a
fine of not less than $50.00 and not more than $500.00 plus court
costs, including reasonable attorney fees incurred by the Township.
No judgment shall commence or be imposed, levied or be payable until
the date of the determination of a violation by the district justice.
B. If the defendant neither pays nor timely appeals the judgment, the
Township may enforce the judgment pursuant to applicable rules of
civil procedure.
C. Each day that a violation continues shall constitute a separate violation
unless the district justice further determines that there was a good
faith basis for the person violating this Part to have believed that
there was no such violation. In such case there shall be deemed to
have been only one such violation until the fifth day following the
date of the district justice's determination of a violation;
thereafter, each day that a violation continues shall constitute a
separate violation.
D. All judgments, costs and reasonable attorney fees collected for the
violation of this Part shall be paid over to the Township.
E. The court of common pleas, upon petition, may grant an order of stay,
upon cause shown, tolling the per diem fine pending a final adjudication
of the violation and judgment.
F. Nothing contained in this Section shall be construed or interpreted
to grant to any person or entity other than the Township the right
to commence any action for enforcement pursuant to this Section.
5. Additional Remedies. In addition to the above remedies, the Township
may also seek remedies and penalties under applicable Pennsylvania
statutes, or regulations adopted pursuant thereto including, but not
limited to, the Stormwater Management Act, 32 P.S. §§ 693.1-693.27,
and the Erosion and Sedimentation Regulations, 25 Pa. Code, Chapter
102. Any activity conducted in violation of this Part or any Pennsylvania
approved watershed stormwater management plan may be declared a public
nuisance by the Township and abatable as such.
[Ord. 671, 3/6/1995, § 114]
ACT
The Stormwater Management Act (Act of October 4, 1978, P.L.
864, No. 167; 32 P.S. §§ 680.1-680.17, as amended by
Act of May 24, 1984, No. 63).
APPLICANT
A landowner or developer who has filed an application for
development including his/her heirs, successors and assigns.
CHANNEL
A perceptible natural or artificial waterway which periodically
or continuously contains moving water or which forms a connecting
link between two bodies of water. It has a definite bed and banks
which confine the water.
CULVERT
A closed conduit for the free passage of surface drainage
under a highway, railroad, canal or other embankment.
DESIGN CRITERIA
1.
Engineering guidelines specifying construction details and materials.
2.
Objectives, results or limits which must be met by a facility,
structure or process in performance of its intended functions.
DETENTION
The slowing, dampening or attenuating of runoff flows entering
the natural drainage pattern or storm drainage system by temporarily
holding water on a surface area in a detention basin or within the
drainage system.
DETENTION POND
A pond or reservoir, usually small, constructed to impound
or retard surface runoff temporarily.
DEVELOPER
The person, persons or any corporation, partnership, association
or other entity or any responsible person therein or agent therefore
that undertakes the activities associated with changes in land use.
The term "developer" is intended to include but not necessarily be
limited to the term "subdivider," "owner" and "builder," even though
the individuals involved in successive stages of a project may vary.
DEVELOPMENT
Any activity, construction, alteration, change in land use
or practice that affect stormwater runoff characteristics.
DISCHARGE
The flow or rate of flow from a canal, conduit, channel or
other hydraulic structure.
DRAINAGE
In general, the removal of surface water from a given area.
Commonly applied to surface water and ground water.
DRAINAGE AREA
1.
The area of a drainage basin or watershed, expressed in acres,
square miles or other unit of area. Also called catchment area, watershed,
river basin.
2.
The area served by a sewer system receiving storm and surface
water, or by a watercourse.
ENCROACHMENT
Any structure or activity which in any manner changes, expands
or diminishes the course, current or cross section of any watercourse,
floodway or body of water.
EROSION
Wearing away of the land by running water, winds and waves.
EROSION CONTROL
The application of measures to reduce erosion of land surfaces.
GROUND WATER
Subsurface water occupying the saturation zone, from which
wells and springs are fed.
GROUND WATER RECHARGE
Replenishment of ground water naturally by precipitation
or runoff or artificially by spreading or injection.
IMPERVIOUS
Not allowing or allowing only with great difficulty the movement
of water; impermeable.
INFILTRATION
1.
The flow or movement of water through the interstices or pores
of a soil or other porous medium.
2.
The absorption of liquid by the soil.
LAND DEVELOPMENT
any of the following activities:
1.
The improvement of one lot or two or more contiguous lots, tracts
or parcels of land for any purpose involving: (a) a group of two or
more residential or nonresidential buildings, whether proposed initially
or cumulatively, or a single nonresidential building on a lot or lots
regardless of the number of occupants or tenure; or (b) the division
or allocation of land or space, whether initially or cumulatively,
between or among two or more existing or prospective occupants by
means or, for the purpose of streets, common areas, leaseholds, condominiums,
building groups or other features.
LAND DISTURBANCE
Any activity involving the changing, grading, transportation,
fill and any other activity which causes land to be exposed to the
danger of erosion.
MAINTENANCE
The upkeep necessary for efficient operation of physical
properties.
NATURAL STORMWATER RUNOFF REGIME
A watershed where natural surface configurations, runoff
characteristics and defined drainage conveyances have attained the
conditions of equilibrium.
OUTFALL
1.
The point, location or structure where drainage discharges from
a sewer, drain or other conduit.
2.
The conduit leading to the ultimate discharge point.
OUTLET CONTROL STRUCTURE
The means of controlling the relationship between the headwater
elevation and the discharge, placed at the outlet or downstream end
of any structure through which water may flow.
PERFORMANCE STANDARD
A standard which establishes an end result or outcome which
is to be achieved but does not prescribe specific means for achieving
it.
RELEASE RATE PERCENTAGE
The watershed factor determined by comparing the maximum
rate of runoff from a subbasin to the contributing rate of runoff
to the watershed peak rate at specific points of interest.
RETENTION POND
A basin, usually enclosed by artificial dikes, that is used
to retard stormwater runoff by temporarily storing the runoff and
releasing it at a predetermined rate.
RETURN PERIOD
The average interval in years over which an event of a given
magnitude can be expected to recur.
RUNOFF
That part of precipitation which flows over the land.
RUNOFF CHARACTERISTICS
The surface components of any watershed which affect the
rate, amount and direction of stormwater runoff. These may include,
but are not limited to, vegetation, soils, slopes and manmade landscape
alterations.
SCS
U.S. Department of Agriculture Soil Conservation Service.
SEDIMENT
Mineral or organic solid material that is being transported
or has been moved from its site of origin by air, water or ice and
has come to rest.
SEDIMENTATION
The process by which mineral or organic matter is accumulated
or deposited by moving water, wind or gravity.
STORM FREQUENCY
The average interval in years over which a storm event of
a given precipitation volume can be expected to occur.
STORM SEWER
A sewer that carries intercepted surface runoff, street water
and other drainage but excludes domestic sewage and industrial waste.
STORMWATER
That portion of precipitation which runs over the land.
STORMWATER COLLECTION SYSTEM
Natural or manmade structures that collect and transport
stormwater through or from a drainage area to the point of final outlet
including, but not limited to, any of the following: conduits and
appurtenant features, canals, channels, ditches, streams, culverts,
streets and pumping stations.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff adopted by Allegheny
County as required by the Stormwater Management Act.
SWALE
A low-lying stretch of land which gathers or carries surface
water runoff.
WATERCOURSE
any channel for conveyance of surface water runoff.
WATERSHED
The entire region or area drained by a river or other body
of water whether natural or artificial. A "designated watershed" is
an area delineated by the Pennsylvania DER and approved by the Environmental
Quality Board for which counties are required to develop watershed
stormwater management plans.
WATERSHED STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff throughout a designated
watershed adopted by Allegheny County as required by the Pennsylvania
Stormwater Management Act.
[Ord. 841, 7/2/2007, § 1]
1. General Requirements.
A. No person in the Township shall allow, or cause to allow, stormwater
discharges into the Township's separate storm sewer system which
are not composed entirely of stormwater, except:
(1)
As provided in Subsection
B below; and
(2)
Discharges allowed under a state or federal permit.
B. Discharges which may be allowed, based on a finding by the Township
that the discharge(s) do not significantly contribute to pollution
of surface waters of the Commonwealth are:
(1)
Discharges from fire-fighting activities.
(2)
Potable water sources, including dechlorinated waterline and
fire hydrant flushings.
(4)
Routine external building washdown (which does not use detergents
or other compounds).
(5)
Air conditioning condensate.
(6)
Water from individual residential car washing.
(7)
Uncontaminated water from foundation or from footing drains.
(8)
Flows from riparian habitats and wetlands.
(10)
Pavement washwaters where spills or leaks of toxic or hazardous
materials have not occurred (unless all spill material has been removed)
and where detergents are not used..
(11)
Dechlorinated swimming pool discharges.
(13)
Uncontaminated groundwater.
C. In the event that the Township determines that any of the discharges identified in Subsection
B significantly contribute to pollution of waters of the Commonwealth, or is so notified by the Pennsylvania Department of Environmental Protection, the Township will notify the responsible person to cease the discharge.
D. Upon notice provided by the Township under Subsection
C, the discharger will have a reasonable time, as determined by the Township, to cease the discharge consistent with the degree of pollution caused by the discharge.
E. Nothing in this Section shall affect a discharger's responsibilities
under state law.
2. Prohibited Connections. The following connections are prohibited,
except as provided in Subsection B above:
A. Any drain or conveyance, whether on the surface or subsurface, which
allows any non-stormwater discharge, including sewage, process wastewater,
and wash water, to enter the separate storm sewer system and any connections
to the storm drain system from indoor drains and sinks; and
B. Any drain or conveyance connected from a commercial or industrial
land use to the separate storm sewer system which has not been documented
in plans, maps, or equivalent records, and approved by the Township.
[Ord. 841, 7/2/2007, § 2]
1. No regulated earth disturbance activities within the Township shall
commence until approval by the Township of an Erosion and Sediment
Control Plan for construction activities.
2. The Pennsylvania Department of Environmental Protection (DEP) has
regulations that require an Erosion and Sediment Control Plan for
any earth disturbance activity of 5,000 square feet or more, under
25 Pa. Code § 102.4(b).
3. In addition, under 25 Pa. Code Chapter 92, a DEP NPDES Construction
Activities permit is required for any earth disturbance one acre or
more with a point source discharge to surface waters or the Township's
storm sewer system, or five acres or more regardless of the planned
runoff (hereinafter collectively referred to as "regulated earth disturbance
activities"). This includes earth disturbance on any portion of, part
of, or during any stage of, a larger common plan of development.
4. Evidence of any necessary permit(s) for regulated earth disturbance activities from the appropriate DEP regional office or County Conservation District must be provided to the Township. The issuance of an NPDES Construction Permit (or permit coverage under the statewide General Permit (PAG-2)) satisfies the requirement of Subsection
3.
5. A copy of the Erosion and Sediment Control Plan and any required
permit, as required by DEP regulations, shall be available at the
project site at all times.
[Ord. 841, 7/2/2007, § 3]
1. No regulated earth disturbance activities within the Township shall
commence until approval by the Township of a plan which demonstrates
compliance with State Water Quality Requirements after construction
is complete.
2. The best management practices (BMPs) must be designed to protect
and maintain existing uses (e.g., drinking water use; cold water fishery
use) and maintain the level of water quality necessary to protect
those uses in all streams, and to protect and maintain water quality
in "special protection" streams, as required by statewide regulations
at 25 Pa. Code Chapter 93 (collectively referred to herein as "State
Water Quality Requirements").
3. To control post-construction stormwater impacts from regulated earth
disturbance activities, State Water Quality Requirements can be met
by BMPs, including site design, which provide for replication of preconstruction
stormwater infiltration and runoff conditions, so that post-construction
stormwater discharges do not degrade the physical, chemical or biological
characteristics of the receiving waters. As described in the DEP comprehensive
Stormwater Management Policy (#392-0300-00, September 28, 2002), this
may be achieved by the following:
A. Infiltration: replication of preconstruction stormwater infiltration
conditions;
B. Treatment: use of water quality treatment BMPs to ensure filtering
out of chemical and physical pollutants from the stormwater runoff;
and
C. Streambank and Streambed Protection: management of volume and rate
of post-construction stormwater discharges to prevent physical degradation
of receiving waters (e.g., from scouring and erosion).
4. DEP has regulations that require municipalities to ensure design,
implementation and maintenance of best management practices (BMPs)
that control runoff from new development and redevelopment (hereinafter
"development") after regulated earth disturbance activities are complete.
These requirements include the need to implement post-construction
stormwater BMPs with assurance of long-term operations and maintenance
of those BMPs.
5. Evidence of any necessary permit(s) for regulated earth disturbance activities from the appropriate DEP regional office or County Conservation District must be provided to the Township. The issuance of an NPDES Construction Permit [or permit coverage under the statewide General Permit (PAG-2)] satisfies the requirements of this Subsection
5.