[Ord. No. 1528,[1] 9-26-2022]
(a)
The Town of McCandless finds that:
(1)
Inadequate management of accelerated runoff of stormwater resulting
from development throughout a watershed increases flows and velocities,
contributes to erosion and sedimentation, overtaxes the carrying capacity
of streams and storm sewers, greatly increases the cost of public
facilities to carry and control stormwater, undermines floodplain
management and flood-control efforts in downstream communities, reduces
groundwater recharge, threatens public health and safety, and increases
non-point-source pollution of water resources.
(2)
A comprehensive program of stormwater management, including
reasonable regulation of development and activities causing accelerated
runoff, is fundamental to the public health, safety, and welfare and
the protection of people of the commonwealth, their resources, and
the environment.
(3)
Stormwater is an important water resource, which provides groundwater
recharge for water supplies and base flow of streams, which also protects
and maintains surface water quality.
(4)
Federal and state regulations require certain municipalities
to implement a program of stormwater controls. These municipalities
are required to obtain a permit for stormwater discharges from their
separate storm sewer systems under the National Pollutant Discharge
Elimination System (NPDES).
(b)
In order to protect the health, safety, and general welfare of the
residents of the Town of McCandless, as well as to protect, sustain,
and enhance the surface water and groundwater resources of the Town,
drainage and stormwater management practices shall be utilized as
directed herein to achieve the following goals and objectives:
(1)
Accommodate site development and redevelopment in a manner that
protects public safety and that is consistent with (or reestablishes)
the natural hydrologic characteristics of each watershed and sustains
groundwater recharge, stream baseflows, stable stream channel (geomorphology)
conditions, the carrying capacity of streams and their floodplains,
groundwater and surface water quality, and aquatic living resources
and their habitats.
(2)
Reduce and minimize the volume of stormwater generated.
(3)
Protect natural infiltration and groundwater recharge rates
in order to sustain groundwater supplies and stream baseflows.
(4)
Maintain runoff characteristics of the site after completion
of development that are consistent with the carrying capacity and
stable channel conditions of the receiving streams.
(5)
Protect water quality by removing and/or treating pollutants
prior to discharge to groundwaters and surface waters throughout the
Town, and protect, restore, and maintain the chemical, physical, and
biological quality of groundwaters and surface waters.
(6)
Protect in-stream channels and geomorphology conditions of the
receiving streams, protect their flood-carrying capacity and aquatic
habitats, and reduce in-stream aggradation, degradation, and scour.
(7)
Reduce flooding impacts and prevent a significant increase in
surface runoff rates and volumes, predevelopment to post-development,
which could worsen flooding downstream in the watershed, enlarge floodplains,
erode stream banks, and create other flood-related health-welfare-property
losses; in general, preserve and restore the natural flood-carrying
capacity of streams and their floodplains.
(8)
Protect adjacent lands from adverse impacts of direct stormwater
discharges.
(9)
Ensure effective long-term operation and maintenance of all
permanent stormwater management facilities.
(10)
Maintain natural drainage patterns and encourage the use of
natural drainage systems.
(11)
Treat and release stormwater as close to the source of runoff
as possible using a minimum of structures and maximizing reliance
on natural processes.
(12)
Maintain the existing water balance in all watersheds, sub-watersheds,
and streams in the Town and protect and/or restore natural hydrologic
characteristics and habitats wherever possible throughout the watershed
systems.
(13)
Address certain requirements of the municipal separate storm
sewer system (MS4) National Pollutant Discharge Elimination System
(NPDES) Phase II Stormwater Regulations.
(14)
Reduce the impacts of runoff from existing developed sites undergoing
redevelopment while encouraging development and redevelopment in urban
areas and areas designated for growth.
(15)
Meet water quality requirements under state law, including regulations
at 25 Pa. Code Chapter 93.4a, to protect and maintain existing uses
and maintain the level of water quality to support those uses in all
streams and to protect and maintain water quality in special-protection
streams.
(16)
Prevent scour and erosion of stream banks and streambeds.
[1]
Editor's Note: This ordinance also repealed former Ch.
913, Stormwater Management, adopted 11-26-2018 by Ord. No. 1481.
[Ord. No. 1528, 9-26-2022]
(a)
Primary authority. The Town of McCandless is empowered to regulate
these activities by the authority of the Act of October 4, 1978, P.L.
864 (Act 167), 32 P.S. § 680.1 et seq., as amended, the
Storm Water Management Act.
[Ord. No. 1528, 9-26-2022]
The standards contained herein shall apply to all regulated
activities within the Town. In addition, all local, county and state
erosion and sedimentation control approvals must be in place to proceed
with any regulated activity.
(a)
Activities regulated by this article include, but are not limited
to, the following:
(1)
Land development and redevelopment.
(2)
Subdivision.
(3)
Construction of new or additional impervious or semipervious
surfaces (driveways, parking lots, etc.).
(4)
Construction of new buildings or additions to existing buildings.
(5)
Diversion or piping of any natural or man-made stream channel.
(6)
Installation of stormwater management facilities or appurtenances
thereto.
(7)
Any earth disturbances or any activities that involve the alteration
or development of land or removal of trees and vegetation in a manner
that may affect post-construction stormwater runoff.
(8)
All stormwater runoff entering the Town's separate storm
sewer system.
(b)
Redevelopments shall conform to the requirements contained in § 913.14(c)(3) when more than a 2,000-square-foot area of an existing facility is reconstructed following the demolition or partial demolition of that facility. The area determination shall be made using the footprint of the area being reconstructed, including all impervious and semi-impervious surfaces proposed in the reconstructed area and including the increased area of any parking lot required to support the reconstructed facility. The area of the parking lot required to support the reconstructed facility shall be determined using the Town Zoning Ordinance[1] requirements for parking. The presence of existing impervious
or semi-impervious surfaces in predeveloped conditions does not justify
a waiver of this provision.
[1]
Editor's Note: See Part 13, Planning and Zoning Code.
[Ord. No. 1528, 9-26-2022]
Any permit or authorization issued or approval based on false,
misleading, or erroneous information provided by an applicant is void
without the necessity of any proceedings for revocation. Any work
undertaken or use established pursuant to such permit or other authorization
is unlawful. No action may be taken by a board, agency or employee
of the municipality purporting to validate such a violation.
[Ord. No. 1528, 9-26-2022]
(a)
If the Town determines that any requirement under this article cannot be achieved for a particular regulated activity, Town Council may, after an evaluation of alternatives, approve measures other than those in this article, subject to § 913.05(b) and (c). The request for a waiver or modification shall originate with the landowner, shall be in writing, and shall accompany the stormwater management site plan submission to the Town. The request shall provide the facts on which the request is based, the provision(s) of the ordinance involved and the proposed modification. The Town Engineer shall review the request to determine if it meets the requirements of this article, including § 913.05(b) and (c), and issue a recommendation to Town Council. If acceptable to Town Council and the regulated stormwater activity involving earth disturbance is less than one acre, Town Council may grant the waiver or modification.
(b)
Waivers or modifications of the requirements of this article may
be approved by Town Council if enforcement will exact undue hardship
because of unique physical circumstances or preexisting site conditions
peculiar to the land in question, provided that the modifications
will not be contrary or detrimental to the public interest and will
achieve the intended outcome, and that the purpose of the article
is preserved. Hardship must be due to such unique physical circumstances
or preexisting site conditions and not the circumstances or conditions
generally created by the provisions of this article, and there is
no possibility that the property can be developed in strict conformity
with the provisions of this article. Cost or financial burden shall
not be considered a hardship. Hardship cannot have been created by
the landowner or developer. Modification shall not substantially or
permanently impair the appropriate use or development of adjacent
property. Modification may be considered if an alternative standard
or approach will provide equal or better achievement of the purpose
of this article.
(c)
No waiver or modification of any regulated stormwater activity involving
earth disturbance greater than or equal to one acre may be granted
by Town Council unless that section is approved in advance by the
Department of Environmental Protection (DEP).
[Ord. No. 1528, 9-26-2022]
The following activities may be exempt from on-site stormwater
runoff control, provided that they follow all other applicable requirements
of this section. An exemption shall apply only to the requirement
for on-site stormwater facilities and the preparation of a stormwater
management plan. All other stormwater management design elements,
such as a storm sewer system, road culverts, erosion and sedimentation
control, and runoff quality, shall be required. All exemption requests
must be filed with the Zoning Officer and approved by the Engineer.
(a)
Regulated activities smaller than 400 square feet of impervious area
are exempt from the requirements of this article to implement SWM
BMPs, unless the activity is found to be a significant contributor
to pollution of the waters of this commonwealth.
(b)
Small project exemption.
(1)
Table 1 and Table 2 present stormwater management requirements for small projects. For projects that propose additional impervious area or earth disturbance to a parcel, the total proposed impervious area and total proposed earth disturbance on the parcel is subject to the requirements of this article. Impervious area is described in § 913.07.
|
Table 1
Stormwater Management Requirements for Increase in Impervious
Area
| ||
|---|---|---|
|
Number
|
Square Feet of Proposed Impervious Surface
|
Stormwater Management Requirement
|
|
1
|
Less than 400
|
No requirements if there were no previous impervious surface
additions
|
|
2
|
400 to 2,500
(small project)
|
Capture and detain the first 2 inches of any storm event
(Appendix F)[1]
|
|
3
|
More than 2,500
|
Comply with requirement of this article
|
|
Table 2
Stormwater Management Requirements for Proposed Earth Disturbance
| ||
|---|---|---|
|
Number
|
Square Feet of Proposed Earth Disturbance
|
Stormwater Management Requirement
|
|
1
|
Less than 10,890
|
No requirements if there were no previous impervious surface
additions
|
|
2
|
10,890 to 43,559
(small project)
|
Capture and detain the first 2 inches of any storm event (Appendix
F)[2]
|
|
3
|
More than 43,559
|
Comply with requirements of this article
|
(2)
An erosion and sedimentation (E&S) control plan must be
submitted to the Town for review and/or approved by the Allegheny
County Conservation District (ACCD), as deemed necessary.
(3)
An approved E&S plan is required to be on-site.
(c)
Emergency exemption. Emergency maintenance work performed for the
protection of public health, safety and welfare may be exempted from
the requirements in this article to obtain approval for a stormwater
management plan before commencement of the activity; however, a written
description of the scope and extent of any emergency work performed
shall be submitted to the Town within two calendar days of the commencement
of the activity. If the Town finds that the work is not an emergency,
then the work shall cease immediately and may not resume until a written
stormwater management plan is submitted and approved.
(d)
Maintenance exemption: any maintenance to an existing stormwater
management system made in accordance with plans and specifications
approved by the Engineer or the Town.
(e)
Gardening: use of land for gardening for home consumption.
(f)
Agricultural activities: agriculture, when operated in accordance
with a conservation plan, nutrient management plan or erosion and
sedimentation control plan approved by the Allegheny County Conservation
District, including activities such as growing crops, rotating crops,
tilling of soil and grazing animals. Installation of new or expansion
of existing farmsteads, animal housing, waste storage and production
areas having impervious surfaces that result in a net increase in
impervious surface of less than 1,000 square feet are exempt from
the requirement to submit a written stormwater management plan.
(g)
Forest management: forest management operations which are consistent
with a sound forest management plan as filed with the Town Land Use
Administrator and which follow the Pennsylvania Department of Environmental
Protection's management practices contained in its publication
Soil Erosion and Sedimentation Control Guidelines for Forestry. Such
operations are required to have an erosion and sedimentation control
plan.
[Ord. No. 1528, 9-26-2022]
As used in this article, the following terms shall have the
meanings indicated:
American Association of State Highway and Transportation
Officials. The website home page for AASHTO is http://transportation1.org/aashtonew/.
Allegheny County Conservation District.
Allegheny County Health Department.
The Storm Water Management Act (Act of October 4, 1978, P.L.
864, No. 167; 32 P.S. §§ 680.1 through 680.17, as amended).
The Girty's Run, Lowries Run, and Pine Creek Stormwater
Management Plan for managing stormwater runoff adopted by the County
of Allegheny as required by the Act of October 4, 1978, P.L. 864 (Act
167), as amended, and known as the "Storm Water Management Act."
The work of producing crops, including tillage, land clearing,
plowing, disking, harrowing, planting, and harvesting crops, or pasturing
and raising of livestock and installation of conservation measures.
Construction of new buildings or impervious area is not considered
an agricultural activity.
A landowner, developer or other person who has filed an application
for approval to engage in any regulated activity at a project site
in the Town.
A geologic formation, group of formations, or part of a formation
that contains sufficient saturated, permeable material to yield useful
quantities of groundwater to wells and springs.
To reduce the magnitude of the flow rate by increasing the
time it takes to release a specified volume of runoff (for example,
the one-year, twenty-four-hour storm event). Attenuation is a method
of reducing the peak flow rates for post-development compared to the
peak flow rates in predevelopment.
The portion of stream discharge derived from groundwater;
the sustained discharge that does not result from direct runoff or
from water diversions, reservoir releases, piped discharges, or other
human activities.
Activities, facilities, designs, measures, or procedures
used to manage stormwater impacts from regulated activities, to meet
state water quality requirements, to promote groundwater recharge,
and to otherwise meet the purposes of this article. Stormwater BMPs
are commonly grouped into one of two broad categories or measures:
structural or nonstructural. In this article, "nonstructural BMPs
or measures" refer to operational and/or behavior-related practices
that attempt to minimize the contact of pollutants with stormwater
runoff, whereas "structural BMPs or measures" are those that consist
of a physical device or practice that is installed to capture and
treat stormwater runoff. Structural BMPs include, but are not limited
to, a wide variety of practices and devices from large-scale retention
ponds and constructed wetlands to small-scale underground treatment
systems, infiltration facilities, filter strips, low-impact design,
bioretention, wet ponds, permeable paving, grassed swales, riparian
or forested buffers, sand filters, detention basins, and manufactured
devices. Structural stormwater BMPs are permanent appurtenances to
the project site.
Cubic feet per second.
A natural or artificial watercourse that conveys, continuously
or periodically, flowing water.
Surface runoff from rainfall events which converges and flows
primarily through water-conveyance features such as swales, gullies,
waterways, channels or storm sewers and which exceeds the maximum
specified flow rates of filters or perimeter controls intended to
control sheet flow.
A series of holistic land development design practices that
maximize protection of key land and environmental resources, preserve
significant concentrations of open space and greenways, evaluate and
maintain site hydrology, and ensure flexibility in development design
to meet community needs for complementary and aesthetically pleasing
development. Conservation design encompasses the following objectives:
conservation/enhancement of natural resources, wildlife habitat, biodiversity
corridors and greenways (interconnected open space); minimization
of environmental impact resulting from a change in land use (minimum
disturbance, minimum maintenance); maintenance of a balanced water
budget by making use of site characteristics and infiltration; incorporation
of unique natural, scenic and historic site features into the configuration
of the development; preservation of the integral characteristics of
the site as viewed from adjoining roads; and reduction in maintenance
required for stormwater management practices. Such objectives can
be met on a site through an integrated development process that respects
natural site conditions and attempts, to the maximum extent possible,
to replicate or improve the natural hydrology of a site.
A conservation district, as defined in Section 3(c) of the
Conservation District Law [3 P.S. § 851(c)], that has the
authority under a delegation agreement executed with the DEP to administer
and enforce all or a portion of the regulations promulgated under
25 Pa. Code Chapter 102.
The Pennsylvania Department of Environmental Protection.
The magnitude and temporal distribution of precipitation
from a storm event, measured in probability of occurrence (e.g., a
five-year storm) and duration (e.g., 24 hours), used in the design
and evaluation of stormwater management systems. Also see "return
period."
An impoundment designed to collect and retard stormwater
runoff by temporarily storing the runoff and releasing it at a predetermined
rate. Detention basins are designed to drain completely shortly after
any given rainfall event and are dry until the next rainfall event.
The prevention of, or to prevent, the discharge, directly
or indirectly, of a given volume and rate of stormwater runoff into
surface waters by temporary storage.
See "project site."
An unstabilized land area where an earth disturbance is occurring
or has occurred.
An artificial waterway for irrigation or stormwater conveyance.
That land area contributing runoff to a single point and
that is enclosed by a ridgeline.
All facilities and natural features used for the movement
of stormwater through and from a drainage area, including, but not
limited to, any and all of the following: conduits, pipes and appurtenant
features, channels, ditches, flumes, culverts, streets, swales, gutters,
as well as all watercourses, water bodies and wetlands.
A construction or other human activity which disturbs the
surface of the land, including, but not limited to, clearing and grubbing;
grading; excavations; embankments; road maintenance; building construction;
and the moving, depositing, stockpiling, or storing of soil, rock
or earth materials.
A right of use of a specified portion of land of another
for a specified purpose.
A professional engineer duly appointed as the Municipal Engineer
and/or the Stormwater Management Engineer for the Town.
Environmental Protection Agency.
The wearing away of land surface by water or wind which occurs
naturally from weather or runoff but is often intensified by human
activity.
The dominant land cover during the five-year period immediately
preceding a proposed regulated activity.
Any residential or commercial building or impervious or semi-impervious
surface.
Federal Emergency Management Agency.
The uppermost perennial tributary in a watershed that has
not yet confluenced with another perennial stream. The confluence
of two first-order streams forms a second-order stream.
Any land area susceptible to inundation by water from any
natural source or delineated by applicable Federal Emergency Management
Agency (FEMA) maps and studies as being a special flood hazard area.
The channel of the watercourse and those portions of the
adjoining floodplains that are reasonably required to carry and discharge
the one-percent-annual-chance flood (100-year flood). Unless otherwise
specified, the boundary of the floodway is as indicated on maps and
flood insurance studies provided by FEMA. In an area where no FEMA
maps or studies have defined the boundary of the floodway, it is assumed,
absent evidence to the contrary, that the floodway extends 50 feet
from the top of the bank of the stream into the floodplain parallel
to the stream.
Planning and activities necessary for the management of forestland.
These include timber inventory and preparation of forest management
plans, silvicultural treatment, cutting budgets, logging road design
and construction, timber harvesting, site preparation and reforestation.
The difference between the elevation of the design flow in
the emergency spillway (usually the 100-year peak elevation) and the
top elevation of the settled basin embankment (that is, top of berm).
The minimum freeboard shall be one foot.
Water that occurs in the subsurface and fills or saturates
the porous openings, fractures and fissures of underground soils and
rock units.
An area where land use or activities generate highly contaminated
runoff, with concentrations of pollutants in excess of those typically
found in stormwater.
A graph of discharge versus time for a selected point in
the drainage system.
Infiltration rates of soils vary widely and are affected
by subsurface permeability as well as surface intake rates. Soils
are classified into four HSGs (A, B, C, and D) according to their
minimum infiltration rate, which is obtained for bare soil after prolonged
wetting. The Natural Resources Conservation Service (NRCS) of the
U.S. Department of Agriculture defines the four groups and provides
a list of most of the soils in the United States and their group classification.
The soils in the area of the development site may be identified from
a soil survey report that can be obtained from local NRCS offices
or Conservation District offices. Soils become less pervious as the
HSG varies from A to D.
The study of the properties, distribution, circulation, and
effects of water on the earth's surface, soil and atmosphere.
See "impervious surface."
A surface that prevents the infiltration of water into the
ground. Impervious surfaces (or areas) shall include, but not be limited
to: roofs; additional indoor living spaces, patios, garages, storage
sheds and similar structures; and any new streets or sidewalks. Decks,
parking areas, and driveway areas are counted as impervious areas
if they directly prevent infiltration. Aggregate areas shall be considered
impervious in post-developed conditions.
Movement of surface water into the soil, where it is absorbed
by plant roots, evaporated into the atmosphere, or percolates downward
to recharge groundwater.
The depth of accumulated rainfall per unit of time.
A defined channel in which surface water is absent during
a portion of the year, as groundwater levels drop below the channel
bottom.
A type of topography or landscape characterized by surface
depressions, sinkholes, rock pinnacles/uneven bedrock surface, underground
drainage, and caves. Karst is formed on carbonate rocks, such as limestone
or dolomite.
Inclusive of any or all of the following meanings:
A low earthen berm constructed perpendicular to the direction
of slope and extending across the width of the slope for the purpose
of intercepting surface runoff and spreading it behind the berm to
enhance infiltration and reduce erosion and runoff from the slope.
The purpose of a level spreader is to prevent concentrated, erosive
flows from occurring and to spread out stormwater runoff uniformly
over the ground as sheet flow.
The total amount (generally measured in pounds or kilograms
per acre per year) of material (sediment, nutrients, oxygen-demanding
material, or other chemicals or compounds) brought into a lake, stream
or water body by inflowing streams, runoff, direct discharge through
pipes, groundwater, the air (aerial or atmospheric deposition) and
other sources over a specific period of time (often annually).
Site design approaches and small-scale stormwater management
practices that promote the use of natural systems for infiltration,
evapotranspiration, and reuse of rainwater. LID can be applied to
new development, urban retrofits, and revitalization projects. LID
utilizes design techniques that infiltrate, filter, evaporate, and
store runoff close to its source. Rather than rely on costly large-scale
conveyance and treatment systems, LID addresses stormwater through
a variety of small, cost-effective landscape features located on-site.
The action taken to restore or preserve the as-built functional
design of any facility or system.
A natural ground cover with less than one viable tree of
a DBH of six inches or greater per 1,500 square feet within 10 years
of application; a cover condition for which SCS curve numbers have
been assigned or to which equivalent Rational Method runoff coefficients
have been assigned.
Municipal separate storm sewer system.
The Town of McCandless.
Created in 1972 under the Clean Water Act to authorize discharges
to local receiving waters only pursuant to governmental permits, in
an effort to reduce point-source and non-point-source pollutants.
Any activity regulated by this article that is not considered
a redevelopment as defined in this article.
National Oceanic and Atmospheric Administration.
Passive site design approaches or regulatory approaches that
positively impact water quality and reduce or minimize the generation
of stormwater runoff without requiring the construction of specific
or discrete stormwater management control structures.
Natural Resources Conservation Service.
Any natural or man-made watercourse or conduit in which water
flows with a free surface.
Also known as "swales," "grass channels," and "biofilters."
These systems are used for the conveyance, retention, infiltration,
and filtration of stormwater runoff.
Pennsylvania Association of Conservation Districts.
Pennsylvania Department of Environmental Protection.
A ground cover of grassland or range with continuous forage
for grazing and greater than 75% ground cover and lightly or only
occasionally grazed; a cover condition for which the Soil Conservation
Service curve numbers have been assigned or to which equivalent Rational
Method runoff coefficients have been assigned.
The maximum rate of stormwater runoff from a specific storm
event.
Pennsylvania Department of Transportation.
The rate of movement of water under hydrostatic pressure
through interstices of rock or soil. For stormwater analysis, it is
typically measured as a distance per unit of time (e.g., inches per
hour).
Any area not defined as impervious.
The ground cover assumption used when analyzing the stormwater
runoff characteristics of a drainage area prior to the proposed development.
The specific area of land where any regulated activities
in the Town are planned, conducted, or maintained.
Any person licensed by the Pennsylvania Department of State
or otherwise qualified by law to perform the work required by this
article.
The depth of accumulated rainfall per unit of time.
Volume per unit of time.
Any water bodies, watercourses, or wetlands into which surface
waters flow.
The replenishment of groundwater through the infiltration
of rainfall, other surface waters, or land application of water or
treated wastewater.
An existing developed property, as of or after the date of
adoption of this article, that is proposed for reconstruction involving
the demolition or partial demolition of the property.
Any earth disturbances or any activities that involve the
alteration or development of land in a manner that may affect post-construction
stormwater runoff.
Activity involving earth disturbance subject to regulation
under 25 Pa. Code Chapter 92, Chapter 102, or the Clean Streams Law.[2]
A watershed or portion of a watershed for which a release
rate has been established by an adopted Act 167 Stormwater Management
Plan.
The percentage of predevelopment peak rate of runoff from
a watershed subarea (as delineated in the Act 167 watershed plan),
which defines the allowable post-development peak discharge from any
development site in that subarea.
An impoundment designed to collect and retard stormwater
runoff by temporarily storing the runoff and releasing it at a predetermined
rate. Retention basins may also be designed to permanently retain
additional stormwater runoff. Retention basins are designed to retain
a permanent pool of water during dry weather.
The prevention of direct discharge of stormwater runoff into
receiving waters or water bodies by temporary or permanent containment
in a pond or depression; examples include systems which discharge
by percolation to groundwater, exfiltration, and/or evaporation processes
and which generally have residence times of less than three days.
The average interval, in years, within which a storm event
of a given magnitude can be expected to occur one time. For example,
the twenty-five-year return period rainfall would be expected to occur
on average once every 25 years.
Pertaining to anything connected with or immediately adjacent
to the banks of a stream or other body of water.
An area of land adjacent to a body of water and managed to
maintain the integrity of stream channels and shorelines to:
See "stormwater."
Soil Conservation Service.
Fragmented material that originated from weathering rocks
and decomposing organic material that is transported by, suspended
in, and eventually deposited in the streambed.
Occurs when sediment particles that have been suspended within
flowing water are deposited on the stream bottom or floodplain.
A surface that allows a certain amount of rainfall or runoff
to be abstracted or infiltrated into the substratum of the area.
A flow process associated with broad, shallow water movement
on sloping ground surfaces that is not channelized or concentrated.
Source Loading and Management Model. This model is based
on small storm hydrology and pollutant runoff from urban land uses.
Pollutant sources are identified, and both structural and nonstructural
stormwater practices can be accounted for in the model.
Those areas identified by the Federal Emergency Management
Agency (FEMA), Federal Insurance Administration (FIA) as floodway
area (FW), flood fringe area (FF), and general floodplain area (FA);
where determined by the Town, identified alluvial soils may be included
as well.
The regulatory requirements to protect, maintain, reclaim,
and restore water quality under Pennsylvania Code Title 25 and the
Clean Streams Law.[3]
The storm of a specific duration, intensity, and frequency.
Is abbreviated as "SWM BMPs" or "BMPs" throughout this article.
A professional engineer hired or appointed by the Town for
the review of stormwater-management-related issues.
The designed and/or constructed features which infiltrate,
treat, collect, convey, channel, store, inhibit, or divert the movement
of stormwater; such practices include structural and nonstructural
practices.
The approved detailed analysis, design, and drawings of the
stormwater management system are required for all construction. The
plan prepared by the developer, or his representative indicates how
stormwater runoff will be managed at the development site in accordance
with this article. "Stormwater management site plan" will be designated
as "SWM site plan" throughout this article.
Drainage runoff from the surface of the land resulting from
precipitation or snow or ice melt.
Any measures that require the design and construction of
a facility to help reduce or eliminate a non-point source of pollution
and control stormwater.
Anything constructed or installed with a fixed location on
the ground or attached to something having a fixed location on the
ground.
A portion of the watershed (basin) that has similar hydrological
characteristics and drains to a common point.
As defined in the Pennsylvania Municipalities Planning Code,
Act of July 31, 1968, P.L. 805, No. 247.[4]
The top elevation of graded and compacted earth underlying
roadway pavement.
An artificial or natural waterway which may contain contiguous
areas of standing or flowing water only following a rainfall event
or is planted with or has stabilized vegetation suitable for soil
stabilization, stormwater treatment, and nutrient uptake, or is designed
to take into account the soil erodibility, soil percolation, slope,
slope length, and contributing drainage area so as to prevent erosion
and reduce the pollutant concentration of any discharge.
Stormwater Management Model. EPA developed this model for
analyzing stormwater quantity and quality associated with runoff from
urban areas. Both single event and continuous simulation can be performed
on catchments having storm sewers, or combined sewers and natural
drainage, for prediction of flows, stages and pollutant concentrations.
Information on SWMM is available at http://www.epa.gov/ceampubl/swater/swmm/index.htm.
Total area of the parcel(s) being developed.
United States Department of Agriculture.
United States Department of Transportation, Federal Highway
Administration.
Any natural or artificial pond, lake, reservoir, or other
area which ordinarily or intermittently contains water, and which
has a discernible shoreline and receives surface water flow.
The uppermost level of saturation of pore space or fractures
by subsurface water in an aquifer. "Seasonal high water table" refers
to a water table that rises and falls with the seasons due either
to natural or man-made causes.
A permanent or intermittent stream or other body of water,
whether natural or man-made, which gathers or carries surface water.
Any and all rivers, streams, creeks, rivulets, impoundments,
ditches, watercourses, storm sewers, lakes, dammed water, wetlands,
ponds, springs, and all other bodies or channels of conveyance of
surface and underground water, or parts thereof, whether natural or
artificial, within or on the boundaries of this commonwealth.
A region or land area drained by a river, watercourse, or
other surface water of this commonwealth to a downstream point.
Those areas that are inundated or saturated by surface water
or groundwater at a frequency and duration sufficient to support,
and that under normal circumstances do support, a prevalence of vegetation
typically adapted for life in saturated soil conditions, including
swamps, marshes, bogs, fens, and similar area.
Land areas that are inundated or saturated by surface water
or groundwater with a frequency and duration sufficient to support,
and that under normal circumstances do support, a prevalence of vegetation
typically adapted for life in saturated soil conditions (wetlands
generally include swamps, marshes, bogs, and similar areas); or areas
that are defined and delineated in accordance with the Federal Manual
for Identifying and Delineating Jurisdictional Wetlands, dated January
10, 1989, and as may be amended from time to time; or as further defined
and delineated by the United States Army Corps of Engineers, the United
States Environmental Protection Agency, or the Pennsylvania Department
of Environmental Protection.
A natural ground cover with more than one viable tree of
a DBH (diameter at breast height) of six inches or greater per 1,500
square feet which existed within 10 years of application; a cover
condition for which SCS curve numbers have been assigned or to which
equivalent rational method runoff coefficients have been assigned.
[Ord. No. 1528, 9-26-2022]
(a)
Standards and intent.
(1)
The management of stormwater on-site, both during and upon completion of the disturbances associated with activities permitted under § 913.03, shall be accomplished in accordance with the standards and criteria of this article. The design of any temporary or permanent facilities and structures and the utilization of any natural drainage systems shall be in full compliance with this article.
(2)
The intent of these design standards is to encourage environmentally
sound stormwater management practices that provide necessary drainage
facilities while protecting the hydrologic characteristics and water
quality of the site and watershed. Developments shall be required
to incorporate stormwater management controls. Stormwater management
design shall blend into the natural environment and be aesthetically
integrated into the site design.
(b)
Applicants shall refer to the Pennsylvania Storm Water Best Management
Practices Manual, as amended, Pennsylvania Handbook of Best Management
Practices for Developing Areas (PACD, 1998), the 2000 Maryland Stormwater
Design Manual (MDE, 2000) or other appropriate references for guidance
in the design of stormwater management facilities most appropriate
to individual site conditions. Objectives for design are to reduce
the volume of stormwater generated, infiltrate runoff at its source
to the maximum extent possible, achieve water quality improvement
at the source or during conveyance, and provide for peak flow attenuation.
Applicants shall examine design alternatives by viewing them in a
series. In addition, applicants are strongly encouraged to use structural
and nonstructural stormwater management practices that reduce or eliminate
the need for detention basins.
(c)
All SWM design work must be completed by a qualified design professional.
All designs proposing the use of an SWM retention or detention facility
with outlet structure(s) shall be completed by a professional engineer
licensed in the Commonwealth of Pennsylvania.
(d)
All development activity within a special flood hazard area designated
by the Federal Emergency Management Agency (FEMA) shall comply with
floodplain provisions of Article 1342 of the Town Code[1] and this paragraph subsection. All development shall be
designed to maintain the flood-carrying capacity of the floodway such
that the base flood elevations are not increased, either upstream
or downstream, unless an approval is received from PADEP. The natural
conveyance characteristics of the site and the receiving floodplain
shall be incorporated into the stormwater management practices proposed
for the site.
[1]
Editor's Note: See now Article 912, Floodplain Construction
and Development Requirements.
(e)
The stormwater management system shall not create an adverse impact
on stormwater quantity or quality in either upstream or downstream
areas. Off-site areas which discharge to or across a site proposed
for development shall be addressed in the stormwater management plan
prepared for the development. No stormwater management plan shall
be approved until it is demonstrated that the runoff from the project
shall not adversely impact downstream areas.
(f)
Existing wetlands shall not be used to meet the minimum design requirements
for stormwater management or stormwater runoff quality treatment,
except when used as part of a treatment train that incorporates a
portion of the outer zone (filter strip) of the wetland's riparian
buffer as a stormwater outfall.
(g)
All proposed stormwater management systems shall be designed to prevent
the pollution of groundwater resources by stormwater, promote safety,
minimize health hazards, preserve natural features and provide infiltration
and groundwater recharge where appropriate. Neither submission of
a plan under the provisions herein nor compliance with the provisions
of these regulations shall relieve any person from responsibility
for damage to any person or property otherwise imposed by law.
(h)
Undue hardship. Waivers or modifications of the requirements of this
article may be approved by the Town if enforcement will exact undue
hardship because of unique physical circumstances or conditions peculiar
to the land in question, provided that the modifications will not
be contrary or detrimental to the public interest and will achieve
the intended outcome, and that the purpose of this article is preserved.
Hardship must be due to such unique physical circumstances or conditions
and not to circumstances or conditions generally created by the provisions
of this article. Cost or financial burden shall not be considered
a hardship. Modifications shall not substantially or permanently impair
the appropriate use or development of adjacent property. A request
for modifications shall be in writing and accompany the stormwater
management site plan submission.
(i)
Where watercourses traverse a development site, drainage easements
shall be provided conforming to the line of such watercourses. The
terms of the easements shall prohibit excavation, the placing of fill
or structures, except as needed for roadways, driveways and walkways,
or any alterations that may adversely affect the flow of stormwater
within any portions of the easement and require the establishment
and protection of riparian buffers.
(j)
For all regulated activities, stormwater management BMPs shall be
designed, implemented, operated, and maintained to meet the purposes
and requirements of this article and to meet all requirements under
Pennsylvania Code Title 25, the Clean Streams Law, and the Storm Water
Management Act.
(k)
Any regulated activity that may affect the stormwater flows toward
or onto a state or county highway right-of-way or facility shall be
designed, implemented, operated, and maintained in accordance with
the regulations of the Pennsylvania Department of Transportation (PennDOT)
or Allegheny County, as the case may be.
(l)
At the time of application for a building permit for any approved
lot created by a subdivision and/or improved as a land development
project, issuance of the permit shall be conditioned upon adherence
to the terms of this article.
(m)
Stormwater discharges to critical areas with sensitive resources
(e.g., special-protection waters, cold water fisheries, recharge areas,
water supply reservoirs, etc.) may be subject to additional performance
criteria or may need to utilize or restrict certain stormwater management
practices.
(n)
For all regulated earth disturbance activities, erosion and sediment
control BMPs shall be designed, implemented, operated, and maintained
during the regulated earth disturbance activities (e.g., during construction)
to meet the purposes and requirements of this article and to meet
all requirements under Pennsylvania Code Title 25 and the Clean Streams
Law. Various BMPs and their design standards are listed in the Erosion
and Sediment Pollution Control Program Manual (E&S Manual), Commonwealth
of Pennsylvania, Department of Environmental Protection, No. 363-2134-008,
as amended and updated.
(o)
No regulated earth disturbance activities within the Town shall commence
until the requirements of this article are met.
(p)
Post-construction water quality protection shall be addressed as
required by the stormwater management requirements contained in this
article.
(q)
Operations and maintenance of permanent stormwater BMPs shall be addressed as required by § 913.19.
(r)
All best management practices (BMPs) used to meet the requirements
of this article shall conform to the state water quality requirements,
and any more-stringent requirements as required by the Town.
(s)
Techniques described in Appendix B (Nonstructural Stormwater Management
Practices)[2] of this article are encouraged, because they reduce the
costs of complying with the requirements of this article and the state
water quality requirements.
[2]
Editor's Note: Appendix B is included as an attachment
to this article.
(t)
In selecting the appropriate BMPs or combinations thereof, the applicant
shall consider the following:
(1)
Total contributing area.
(2)
Permeability and infiltration rate of the site soils.
(3)
Slope and depth to bedrock.
(4)
Seasonal high water table.
(5)
Proximity to building foundations and wellheads.
(6)
Erodibility of soils.
(7)
Land availability and configuration of the topography.
(8)
Peak discharge and required volume control.
(9)
Stream bank erosion.
(10)
Efficiency of the BMPs to mitigate potential water quality problems.
(11)
The volume of runoff that will be effectively treated.
(12)
The nature of the pollutant being removed.
(13)
Maintenance requirements.
(14)
Creation/protection of aquatic and wildlife habitat.
(u)
Transference of runoff from one release rate district to another
shall be prohibited unless approved by the Town.
(v)
Completion of applicable PA DEP PCSM worksheets documenting volume,
rate, and water quality requirements shall be completed for all projects
unless they are considered a small project or do not require any stormwater
management.
(w)
At the discretion of the Town or the Town Engineer, the Town reserves
the right to require the completion of additional studies for developments
occurring in areas of concern.
[Ord. No. 1528, 9-26-2022]
(a)
This section shall pertain to any and all persons making any change
of land in the Town that will block, close, impede, or divert any
existing drain or block, close, impede, or divert any watercourse
or stormwater collection system.
(b)
The provisions of this section are established with the following
intentions:
(1)
Preventing the creation of swamps, bogs, pools of drainage flow,
stagnant water or other similar conditions that do, or threaten to,
injuriously affect the health and welfare of the residents of the
Town.
(2)
Safeguarding the residents of the Town from consequences of
flood and stormwaters diverted from their accustomed courses.
(c)
Prohibited acts.
(1)
No person shall block, close, impede or divert any watercourse
or drain in the Town.
(2)
No person shall cause discharge or drainage into a sewer line
or into a drain or watercourse without first obtaining a written permit
from the Town.
(3)
No person shall make any construction on or adjacent to any
street, alley or other public thoroughfare in the Town in such manner
as to block, partially block or bridge any gutter, drain or watercourse
in or adjacent to such street, alley or other public thoroughfare
without first obtaining a written permit from the Town.
(4)
No one shall be permitted to direct or divert water onto or
into a public street or public street right-of-way so as to cause
an accumulation of water or ice which, in the opinion of the Town
Manager or Police Chief, constitutes a safety hazard.
(5)
No person shall throw, drop, or deposit into any of the storm
sewers within the Town any garbage, refuse, rubbish, petroleum, chemical
products, liquid wastes, grass, tree or brush trimmings, or any litter,
as defined by Town ordinance.
(6)
No person(s) shall permit material from an unpaved road or unpaved
driveway to enter a public road or public storm sewer.
(d)
Permit; prerequisites. The Town shall issue a written permit authorizing any installation or construction otherwise a violation of § 913.09(c) only after:
(1)
All applicable permits from the PA DEP, U.S. Army Corps of Engineers,
and the Allegheny County Conservation District have been issued.
(2)
The receipt of a dated request signed by the person desiring
such installation or construction. If such request contemplates the
installation of a sewer line, then such request shall set forth such
information as will adequately locate the beginning and end of the
sewer line, the type of sewer line to be used, the thickness of the
wall of the sewer line to be used, the material from which the sewer
line is constructed and the amount, contents and location of fill,
if any, that will be placed over the sewer line to be installed. The
request for any other installation or construction must set forth
the proposed installation and/or construction in such detail as shall
be requested by the Town.
(3)
The Town ascertains that the construction and/or installation
described above does not threaten to create any such condition as
is sought to be avoided by the intent of this article.
(4)
The applicant has furnished such engineering plans, specifications
and information, or has agreed to reimburse the Town for the preparation
of such engineering plans, specifications and information, as, in
the opinion of the Town, may be required for a proper evaluation of
the particular installation or construction.
