Township of Cranberry, PA
Butler County
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Table of Contents
Table of Contents
[Ord. 2011-415, 5/5/2011, § 3]
These regulations shall be known as and referred to as the "Township of Cranberry Stormwater Management Regulations" in accordance with the Butler County Act 167 Stormwater Management Plan.
[Ord. 2011-415, 5/5/2011, § 3]
The general purposes of these regulations are to promote health, safety, and welfare within Cranberry Township, Butler County, by minimizing the harms and maximizing the benefits described in § 17-102 of Chapter 17 through provisions intended to:
A. 
Meet legal water quality requirements under state law, including regulations at 25 Pa. Code Chapter 93 to protect, maintain, reclaim, and restore the existing and designated uses of the waters of the commonwealth.
B. 
Manage accelerated runoff and erosion and sedimentation problems close to their source by regulating activities that cause these problems.
C. 
Preserve the natural drainage systems as much as possible.
D. 
Maintain groundwater recharge to prevent degradation of surface and groundwater quality and to otherwise protect water resources.
E. 
Maintain existing flows and quality of streams and watercourses.
F. 
Preserve and restore the flood-carrying capacity of streams and prevent scour and erosion of stream banks and streambeds.
G. 
Manage stormwater impacts close to the runoff source with a minimum of structures and a maximum use of natural processes.
H. 
Provide procedures, performance standards, and design criteria for stormwater planning and management.
I. 
Provide proper operations and maintenance of all temporary and permanent stormwater management facilities and best management practices (BMPs) that are constructed and implemented.
J. 
Provide standards to meet the NPDES permit requirements.
K. 
For MS4 permittees, implement an illegal discharge detection and elimination program in MS4 permanent urbanized areas to address non-stormwater discharges into Cranberry Township's separate storm sewer system.
[Ord. 2011-415, 5/5/2011, § 3]
The Township shall be responsible for the administration, enforcement and interpretation of the Stormwater Management Regulations.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
These regulations shall be applicable to the construction of all public and private improvements in the Township as follows.
A. 
In Cranberry Township all regulated activities and all activities that may affect stormwater runoff, including land development and earth disturbance activity, are subject to regulation by this Part.
B. 
Cranberry Township 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, and the Public Private Improvement Code.
C. 
Cranberry Township also is empowered to regulate land use activities that affect runoff by the authority of the Act of July 31, 1968, P.L. 805, No. 247, the Pennsylvania Municipalities Planning Code, as amended.[1]
[1]
Editor's Note: See 53 P.S. § 10101 et seq.
D. 
Earth disturbance activities and associated stormwater management controls are also regulated under existing state law and implementing regulations. This Part shall operate in coordination with those parallel requirements; the requirements of this Part shall be no less restrictive in meeting the purposes of this Part than state law.
E. 
"Regulated activities" are any earth disturbance activities or any activities that involve the alteration or development of land in a manner that may affect stormwater runoff. "Regulated activities" include, but are not limited to, the following listed items:
(1) 
Earth disturbance activities.
(2) 
Land development.
(3) 
Subdivision.
(4) 
Construction of new or additional impervious or semipervious surfaces.
(5) 
Construction of new buildings or additions to existing buildings.
(6) 
Diversion or piping of any natural or man-made stream channel.
(7) 
Installation of stormwater management facilities or appurtenances thereto.
(8) 
Installation of stormwater BMPs.
2. 
See § 17-350.7C(1)(c) of this Part for exemption/modification criteria.
[Ord. 2011-415, 5/5/2011, § 3]
Public and private improvements constructed by any person or entity, including a developer, shall be constructed in accordance with Part 3 of this chapter.
[Ord. 2011-415, 5/5/2011, § 3]
All construction of public and private improvements in the Township by developers shall be conducted in accordance with this Part.
A. 
Notice Prior to Start of Work. In order that the Township may provide proper inspection and emergency services during construction, the developer shall file with the Township a notice of commencement in the form set forth in Part 3 not less than two days prior to the start of work and shall also submit the following:
(1) 
Names, addresses and telephone numbers of the superintendent, contractor and subcontractors and other responsible persons to be contacted in case of emergencies.
(2) 
A general schedule of construction which is to be updated during construction if changes are made.
B. 
Supervision and Superintendence.
(1) 
The developer shall supervise and direct the work and be solely responsible to see that the work is done in accordance with the construction standards and specifications.
(2) 
The developer shall have available at all times while construction is continuing a competent superintendent who may be contacted during an emergency. The superintendent will be the developer's representative at the site and shall have authority to act on behalf of the developer. All communications given to the superintendent shall be as binding as if given to the developer. If the superintendent is replaced, the developer shall give written notice thereof to the Township immediately.
(3) 
The developer shall be fully responsible for the acts and omissions of the contractors, subcontractors, persons and organizations directly or indirectly in his employ.
C. 
Site Appearance. The developer shall keep the site free from accumulation of waste materials, rubbish and other debris resulting from the work. At the completion of the work, the developer shall remove all waste materials, rubbish and debris from and about the site as well as all tools, construction equipment and machinery, and surplus materials and shall leave the site clean.
D. 
Parking. No construction vehicles, vehicles of construction employees, equipment, materials or supplies shall encroach onto a public street. In the case where there is a private street or proposed public street not yet accepted by the Township, the developer shall maintain an eighteen-foot unobstructed clear path on such street for emergency vehicle purposes.
E. 
Hours of Construction. The operation of heavy construction or excavation machinery, including, but not limited to, bulldozers, high-lifts, backhoes, trucks, power shovels, pumps and jack hammers, and the operation of equipment such as saws and drills or any other type of machinery in conjunction with the construction of public and private improvements which causes noise sufficient to disturb the peace and general tranquility of the general public shall be prohibited in the entire Township between the hours of 9:00 p.m. and 7:00 a.m., Monday through Saturday, and all day Sunday.
F. 
Dust Control. The developer shall maintain the site so as to control the dust. The developer shall employ measures necessary to control dust. At the Township's direction, the Township may require routine maintenance of the site for dust control if, in the opinion of the Township, the developer is not maintaining the site in a reasonable manner.
G. 
Responsibility for Compliance. The developer shall have the sole responsibility to comply with all federal, state, and local laws, and the Township disclaims any duty to enforce any violation of such laws or inform the developer of noncompliance.
H. 
Notwithstanding any provision(s) of this Part, including exemptions, any landowner or 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 also shall include actions as are required to manage the rate, volume, direction, and quality of resulting stormwater runoff in a manner which otherwise adequately protects health, property, and water quality.
[Ord. 2011-415, 5/5/2011, § 3]
A Township road occupancy permit is required for the installation of any utilities or stormwater infrastructure within an existing public street in accordance with the procedures and requirements set forth in this Code.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
It shall be unlawful for any developer or public utility company to construct public or private improvements regulated by this Part, or cause the same to be done, in conflict with or in violation of any of the provisions of this Part.
2. 
Notice of Violation. The Township shall serve a notice of violation or order on the developer or utility company responsible for the violation of the provisions of this Part or of the plans approved thereunder. Such order shall direct the discontinuance of the illegal action or condition and the abatement of the violation.
A. 
In the event that a person fails to comply with the requirements of this Part, an approved SWM site plan, or fails to conform to the requirements of any permit or approval issued hereunder, the Township shall provide written notification of the violation. Such notification shall set forth the nature of the violation(s) and establish a time limit for correction of these violation(s).
B. 
Failure to comply within the time specified shall subject such person to the penalties provisions of this Part. All such penalties shall be deemed cumulative and shall not prevent the Township from pursuing any and all other remedies. It shall be the responsibility of the owner of the real property on which any regulated activity is proposed to occur, is occurring, or has occurred to comply with the terms and conditions of this Part.
3. 
Any person who shall violate a provision of this Part or who shall fail to comply with any requirement thereof, upon conviction thereof in an action brought before a district judge in the manner provided for the enforcement of summary offenses under the Pennsylvania Rules of Criminal Procedure, shall be sentenced to pay a fine of not more than $1,000 plus costs and, in default of payment of said fine and costs, to a term of imprisonment not to exceed 90 days. Each day that a violation of this Part continues or each section of this Part which shall be found to have been violated shall constitute a separate offense.
A. 
In addition, the Township, through its solicitor, may institute injunctive, mandamus, or any other appropriate action or proceeding at law or in equity for the enforcement of this Part. Any court of competent jurisdiction shall have the right to issue restraining orders, temporary or permanent injunctions, mandamus, or other appropriate forms of remedy or relief.
4. 
Abatement of Violation. The imposition of the penalties herein prescribed shall not preclude the Township from instituting appropriate action to prevent unlawful construction or to restrain, correct or abate a violation or to stop an illegal act.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
Notice to Stop Work. Upon notice from the Township that work on the installation of public or private improvements is being prosecuted contrary to the provisions of this Part, such work shall be immediately stopped. The stop-work order shall be in writing and shall be given to the developer or to the person doing the work. The stop-work order shall state the conditions under which the work may be resumed.
2. 
Unlawful Continuance. Any person who shall continue any work in or about a work site after having been served with a stop-work order, except such work as that person is directed to perform to remove a violation or unsafe conditions, shall be liable to the violations and penalties set forth herein.
[Ord. 2011-415, 5/5/2011, § 3]
The procedure for acceptance of public improvements shall be in accordance with the Subdivision and Land Development Ordinance [Chapter 22]. The Township is under no obligation to accept such dedication, and acceptance may occur only by action of the governing body of the Township.
[Ord. 2011-415, 5/5/2011, § 3]
This Part may be amended by action of the Supervisors in accordance with this Public and Private Improvements Code; however, the construction standards in Part 3 of this chapter as they pertain to any particular public improvement may be amended by motion of the Supervisors upon recommendation of the Engineer and Township Manager.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
Should there arise any dispute between the developer or the Township with regard to any provisions of this Part, the developer and Township may elect to use the provisions of this section to mediate such dispute. Participation in mediation shall be wholly voluntary. The appropriateness of mediation shall be determined by the particulars of each case and the willingness of the parties to negotiate.
2. 
Parties agreeing to enter into mediation shall first enter into a written mediation agreement containing at least the following minimum provisions.
A. 
Identification of the selected mediator who, at a minimum, shall have a working knowledge of municipal zoning and subdivision procedures and engineering practices. The mediator shall have demonstrated skills in mediation.
B. 
Time frame in which the mediation will be conducted and completed.
C. 
Provisions for suspension of time limits, if necessary, for applications subject to the same in regards to subdivision, land development, PRD or other application or procedures pursuant to the Pennsylvania Municipalities Planning Code, 53 P.S. § 10101 et seq.
D. 
Identification of all parties and affording them the opportunity to participate.
E. 
Subject to legal restraints, determining whether the mediation sessions or parts thereof shall be open to the public.
F. 
Identification as to whether the results of such mediation shall be binding upon the parties.
3. 
Funding for mediation shall be born equally by the Township and the developer.
4. 
Mediated solutions shall be in writing and signed by the parties and become subject to review and approval by the appropriate decisionmaking body when necessary.
5. 
No offers or statements made in the mediation sessions, excluding the final written mediated agreement, shall be admissible as evidence in any subsequent judicial or administrative proceedings.
[Ord. 2011-415, 5/5/2011, § 3]
No subdivision and/or land development shall be finally approved unless the public and private improvements as shown on plans have been improved, constructed or installed as may be required by Chapter 22, Subdivision and Land Development. In lieu of the completion of any improvements required as a condition for the final approval of plans, the developer shall deposit with the municipality a financial security in an amount sufficient to cover the costs of such improvements which may be required in conformance with the requirements of the Pennsylvania Municipalities Planning Code. The deposit of financial security shall be in a format and amount as determined acceptable by the Township and in accordance with Chapter 22, Subdivision and Land Development, Part 3, Administration, § 22-305, Subsection 10.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
Neither the granting of any approval under this Part nor the compliance with the provisions of this Part, or with any condition imposed by a Township 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 damages to persons or property.
2. 
The granting of a permit that 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. 2011-415, 5/5/2011, § 3]
1. 
A violation of any provision of this Part is hereby deemed a public nuisance.
2. 
Each day that a violation continues shall constitute a separate violation.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
In the event that a person fails to comply with the requirements of this Part, an approved SWM site plan, or fails to conform to the requirements of any permit or approval issued hereunder, the Township shall provide written notification of the violation. Such notification shall set forth the nature of the violation(s) and establish a time limit for correction of these violation(s).
2. 
Failure to comply within the time specified shall subject such person to the penalties provisions of this Part. All such penalties shall be deemed cumulative and shall not prevent the Township from pursuing any and all other remedies. It shall be the responsibility of the owner of the real property on which any regulated activity is proposed to occur, is occurring, or has occurred to comply with the terms and conditions of this Part.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
The Township governing body is hereby authorized and directed to enforce all of the provisions of this Part. The approved SWM site plan shall be on file at the project site throughout the duration of the construction activity. The Township or its designee may make periodic inspections during construction.
2. 
Adherence to Approved SWM Site Plan.
A. 
It shall be unlawful for any person, firm, or corporation to undertake any regulated activity on any property except as provided for by an approved SWM site plan and pursuant to the requirements of this Part.
B. 
It shall be unlawful to alter or remove any control structure required by the SWM site plan pursuant to this Part.
C. 
It shall be unlawful to allow a property to remain in a condition that does not conform to an approved SWM site plan.
3. 
Stormwater BMPs shall be inspected by the landowner or the landowner's designee according to the inspection schedule described on the SWM site plan for each BMP.
A. 
The Township may require copies of the inspection reports, in a form as stipulated by the Township.
B. 
If such inspections are not conducted or inspection reports not submitted as scheduled, the Township, or its designee, may conduct such inspections and charge the owner appropriate fees. Nonpayment of fees may result in a lien against the property.
4. 
PADEP or its designees normally ensure compliance with any permits issued, including those for stormwater management. In addition to PADEP compliance programs, the Township or their Township assignee may inspect all phases of the installation of temporary or permanent stormwater management facilities.
5. 
Prior to conducting such inspections, the Township shall inform the owner of its intent to conduct such inspections. The owner shall be given 30 days to conduct required inspections and submit the required inspection reports to the Township.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
Any person aggrieved by any action of the Township or its designee relevant to the provisions of this Part may appeal to the Township within 30 days of that action by directing a written appeal to the Township Department of Code Enforcement.
2. 
Any person aggrieved by any decision of the Township relevant to the provisions of this Part may appeal said decisions in accordance with the Municipalities Planning Code 53 P.S. § 10909.1.
[Ord. 2011-415, 5/5/2011, § 3]
As used in this Part, the following terms shall have the meanings indicated:
ACCELERATED EROSION
The removal of the surface of the land through the combined action of human activity and natural processes at a rate greater than would occur because of the natural process alone.
AGRICULTURAL ACTIVITIES
Activities associated with agriculture, such as agricultural cultivation, agricultural operation, and animal heavy-use areas. This includes the work of producing crops, tillage, land clearing, plowing, disking, harrowing, planting, 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.
ALTERATION
As applied to land, a change in topography as a result of the moving of soil and rock from one location or position to another; changing of surface conditions by causing the surface to be more or less impervious; land disturbance.
APPLICANT
A landowner or developer, as hereinafter defined, who has filed an application for development, including his heirs, successors and assigns.
AS-BUILT PLAN
A drawing showing the final as-built location, elevation and/or depth, size and materials of all completed public and private improvements as well as all easements.
BEST MANAGEMENT PRACTICES (BMPs)
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 Part. Stormwater BMPs are commonly grouped into one of two broad categories or measures: nonstructural or structural. "Nonstructural BMPs" are measures referred to as operational and/or behavior-related practices that attempt to minimize the contact of pollutants with stormwater runoff whereas "structural BMPs" are measures the 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.
CARTWAY
That paved road surface from front of curb to front of curb.
CHANNEL EROSION
The widening, deepening, and headward cutting of small channels and waterways due to erosion caused by moderate to large floods.
CISTERN
An underground reservoir or tank used for storing rainwater.
CONSERVATION DISTRICT
The Butler County Conservation District. The Butler County Conservation District has the authority under a delegation agreement executed with the Department of Environmental Protection to administer and enforce all or a portion of the regulations promulgated under 25 Pa. Code Chapter 102.
CONSTRUCTION STANDARDS
The construction standards for streets, stormwater management facilities, sanitary sewer systems, pedestrian circulation, driveways, parking areas, fire hydrants, guiderails, cable TV and other facilities as set forth in this Part.
CULVERT
Any structure not classified as a bridge that provides an opening under the roadway.
DAM
An artificial barrier, together with its appurtenant works, constructed for the purpose of impounding or storing water or another fluid or semifluid, or a refuse bank, fill or structure for highway, railroad or other purposes which does or may impound water or another fluid or semifluid.
DESIGNEE
The agent of this Township and/or agent of the governing body involved with the administration, review or enforcement of any provisions of this Part by contract or memorandum of understanding.
DESIGN SPEED
Anticipated posted speed limit plus five miles per hour.
DESIGN STORM
The magnitude and temporal distribution of precipitation from a storm event measured in probability of occurrence (e.g., a twenty-five-year storm) and duration (e.g., 24 hours), used in the design and evaluation of stormwater management systems. Also see "return period."
DETENTION BASIN
A stormwater facility that collects and temporarily stores surface runoff and releases it at a controlled rate. Detention basins may be classified into the following categories:
A. 
A detention basin designed to completely drain following a storm event. (See Chapter 17.)
B. 
A detention basin designed to completely drain following a storm event and which blends into the surrounding environment by being curvilinear in shape and using native plants to provide soil stabilization. (See Chapter 17.)
C. 
Detention storage located in underground tanks or vaults designed to provide water quantity control through detention of stormwater runoff.
D. 
(1) 
A basin that has a permanent pool of water throughout the year.
(2) 
Also may be called a "wet basin" or "retention pond." (See Chapter 17.)
DETENTION VOLUME
The volume of runoff that is captured and released into waters of the commonwealth at a controlled rate.
DEVELOPER
Any landowner, not a public utility company, agent of such landowner, including the landowner's contractor or resident or superintendent or tenant with permission of such landowner, who constructs or causes to be constructed any public or private improvements anywhere in the Township not under a contract.
DISTURBED AREA
An unstabilized land area where an earth disturbance activity is occurring or has occurred.
DOWNSLOPE PROPERTY LINE
That portion of the property line of the lot, tract, or parcels of land being developed located such that all overland or pipe flow from the site would be directed toward it.
DRAINAGE CONVEYANCE FACILITY
A stormwater management facility designed to convey stormwater runoff and shall include streams, channels, swales, pipes, conduits, culverts, storm sewers, etc.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the use of private land for stormwater management, drainage, or conveyance purposes.
DRAINAGEWAY
Any natural or artificial watercourse, trench, ditch, pipe, swale, channel, or similar depression into which surface water flows.
DRIVEWAY
A private area used exclusively for circulation and ingress and egress to a street by the owner or owners or visitors of the lot. All driveways shall meet the requirements of this Part.
DRY BASIN
A detention basin designed to completely drain following a storm event.
DWELLING, SINGLE-FAMILY
A residential building containing one dwelling unit occupied by one family and which is the only principal building on the lot.
EARTH DISTURBANCE ACTIVITY
A construction or other human activity which disturbs the surface of the land, including, but not limited to, clearing and grubbing, grading, excavations, embankments, land development, agricultural plowing or tilling, timber harvesting activities, road maintenance activities, mineral extraction, and the moving, depositing, stockpiling, or storing of soil, rock or earth materials.
EMERGENCY
Any unforeseen circumstance that calls for immediate action.
ENGINEER
The Township Engineer who is charged with the design and inspection of the work, and with determining the quantities of materials and labor to be paid for. During the execution of the work the Engineer shall also be interpreted to mean the assistant, inspector, or other representative acting within the authority given. The Engineer is to be considered an agent of the Township.
EROSION
The movement of soil particles by the action of water, wind, ice, or other natural forces.
EROSION AND SEDIMENT POLLUTION CONTROL PLAN
A plan that is designed to minimize accelerated erosion and sedimentation.
EXCEPTIONAL VALUE WATERS
Surface waters of high quality which satisfy Pa. Code Title 25, Environmental Protection, Chapter 93, Water Quality Standards, 93.4b(b) (relating to antidegradation).
EXISTING CONDITIONS
The initial condition of a project site prior to the proposed construction. If the initial condition of the site is undeveloped land and not forested, the land use shall be considered as "meadow" unless the natural land cover is documented to generate lower curve numbers or Rational "C" coefficient.
FEMA
The Federal Emergency Management Agency.
FINANCIAL SECURITY
A corporate bond letter of credit or escrow account from a surety or a financial institution acceptable to the Township, naming the Township as obligee in forms specified in Part 3 of this chapter.
FLOOD
A temporary inundation of normally dry land areas.[1]
FLOODPLAIN
Any land area susceptible to inundation by water from any natural source or delineated by applicable Department of Housing and Urban Development, Federal Insurance Administration Flood Hazard Boundary, mapped as being a special flood hazard area. Included are lands adjoining a river or stream that have been or may be inundated by a one-hundred-year flood. Also included are areas that comprise Group 13 soils, as listed in Appendix A of the Pennsylvania Department of Environmental Protection (PADEP) Technical Manual for Sewage Enforcement Officers (as amended or replaced from time to time by PADEP).
FLOODWAY
The channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot.
[Amended by Ord. 2015-454, 5/6/2015]
FOREST MANAGEMENT/TIMBER OPERATIONS
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.
FREEBOARD
A vertical distance between the elevation of the design high water and the top of a dam, levee, tank, basin, or diversion ridge. The space is required as a safety margin in a tank, pond or basin.
A. 
A slope, usually of a road, channel or natural ground specified in percent and shown on plans as specified herein.
B. 
To finish the surface of a roadbed, top of embankment or bottom of excavation.
GROUNDWATER RECHARGE
Replenishment of existing natural underground water supplies.
HEC-HMS MODEL CALIBRATED (HYDROLOGIC ENGINEERING CENTER HYDROLOGIC MODELING SYSTEM)
A computer-based hydrologic modeling technique adapted to the watershed(s) in Butler County for the Act 167 Plan. The model has been calibrated by adjusting key model input parameters.
HIGH-QUALITY WATERS
Surface water having quality that exceeds levels necessary to support propagation of fish, shellfish, and wildlife and recreation in and on the water by satisfying Pa. Code Title 25, Environmental Protection, Chapter 93, Water Quality Standards, 93.4b(a).
HYDROLOGIC SOIL GROUP (HSG)
Infiltration rates of soils vary widely and are affected by subsurface permeability as well as surface intake rates. Soils are classified into one of four HSGs (A, B, C, and D) according to their minimum infiltration rate, which is obtained for bare soil after prolonged wetting. The Natural Resource Conservation Service (NRCS) of the United States 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 interest may be identified from a soil survey report from the local NRCS office or the County Conservation District.
IMPERVIOUS SURFACE (IMPERVIOUS AREA)
A surface that prevents the infiltration of water into the ground. Impervious surface (or areas) includes, but is not limited to: roofs, additional indoor living spaces, patios, garages, storage sheds and similar structures, parking or driveway areas, and any new streets and sidewalks. Any surface areas proposed to initially be gravel or crushed stone shall be assumed to be impervious surfaces.
IMPOUNDMENT
A retention or detention basin designed to retain stormwater runoff and release it at a controlled rate.
INFILTRATION STRUCTURES
A structure designed to direct runoff into the ground (e.g., french drains, seepage pits, seepage trench, etc.).
INLET
A surface connection to a closed drain. A structure at the diversion end of a conduit. The upstream end of any structure through which water may flow.
LAND DEVELOPMENT (DEVELOPMENT)
Any of the following activities:
A. 
The improvement of one lot or two or more contiguous lots, tracts, or parcels of land for any purposes involving:
(1) 
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.
(2) 
The division or allocation of land or space, whether initially or cumulatively, between or among two or more existing or prospective occupants by means of or for the purpose of streets, common areas, leaseholds, condominiums, building groups or other features.
B. 
A subdivision of land.
LANDOWNER
The legal or beneficial owner or owners of a lot, including the holder of an option or contract to purchase (whether or not such option or contract is subject to any conditions), a lessee (if he is authorized under the lease to exercise the rights of the landowner) or other persons having a proprietary interest in the lot.
LANE WIDTH
The width of the travel lane. Typically set at 11 feet when painted with yellow and white lines.
LOW-IMPACT DEVELOPMENT (LID)
An approach to land development that uses various land planning and design practices and technologies to simultaneously conserve and protect natural resource systems and reduce infrastructure costs. LID still allows land to be developed, but in a cost-effective manner that helps mitigate potential environmental impacts.
MAIN STEM (MAIN CHANNEL)
Any stream segment or other runoff conveyance facility used as a reach in the Butler County Act 167 watershed hydrologic model(s).
MANNING EQUATION (MANNING FORMULA)
A method for calculation of velocity of flow (e.g., feet per second) and flow rate (e.g., cubic feet per second) in open channels based upon channel shape, roughness, depth of flow and slope. "Open channels" may include closed conduits so long as the flow is not under pressure.
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)
The federal government's system for issuance of permits under the Clean Water Act, which is delegated to PADEP in Pennsylvania.
NATURALIZED BASIN
A detention basin designed to completely drain following a storm event and which blends into the surrounding environment by being curvilinear in shape and using native plants to provide soil stabilization.
NOAA ATLAS 14
Precipitation-Frequency Atlas of the United States, Atlas 14, Volume 2, US Department of Commerce, National Oceanic and Atmospheric Administration, National Weather Service, Hydrometeorological Design Studies Center, Silver Spring, Maryland (2004). NOAA's Atlas 14 can be accessed at Internet address http://hdsc.nws.noaa.gov/hdsc/pfds/.
NON-POINT SOURCE POLLUTION
Pollution that enters a water body from diffuse origins in the watershed and does not result from discernible, confined, or discrete conveyances.
NRCS
Natural Resource Conservation Service [previously Soil Conservation Service (SCS)].
OPEN CHANNEL
A drainage element in which stormwater flows with an open surface. Open channels include, but shall not be limited to, natural and man-made drainageways, swales, streams, ditches, canals, and pipes not under pressure.
A. 
Point where water flows from a conduit, stream, or drain;
B. 
"Point Source" as described in 40 CFR 122.2 at the point where the Township's storm sewer system discharges to surface waters of the commonwealth.
OUTLET
Points of water disposal from a stream, river, lake, tidewater, or artificial drain.
PADEP
The Pennsylvania Department of Environmental Protection.
PARKING AREA
A public or private garage or a paved, open, off-street area other than a driveway or street with adequate means of access, which meets the requirements of this Part and which is used exclusively for the parking of vehicles of occupants or visitors of the lot; however, a driveway serving a single-family dwelling or which is for the exclusive use of an individual dwelling unit in a residential building may be used as a parking area.
PARKING LOT STORAGE
Involves the use of impervious parking areas as temporary impoundments with controlled release rates during rainstorms.
PEAK DISCHARGE
The maximum rate of stormwater runoff from a specific storm event.
PERSON
An individual, partnership, public or private association or corporation, or a governmental unit, public utility or any other legal entity whatsoever which is recognized by law as the subject of rights and duties.
PERVIOUS AREA
Any area not defined as impervious.
PIPE
A culvert, closed conduit, or similar structure (including appurtenances) that conveys stormwater.
PLANNING ADVISORY COMMISSION
The Planning Advisory Commission of Cranberry Township.
POINT SOURCE
Any discernible, confined, or discrete conveyance, including, but not limited to: any pipe, ditch, channel, tunnel, or conduit from which stormwater is or may be discharged, as defined in state regulations at 25 Pa. Code § 92.1.
PRIVATE IMPROVEMENT
A street, sidewalk, walkway, gutter, curb, sewer, water line, driveway, parking area, streetlight, street sign, or related facility to be operated and maintained by a private entity, but which must comply with this Part.
PROBABLE MAXIMUM FLOOD (PMF)
The flood that may be expected from the most severe combination of critical meteorological and hydrologic conditions that are reasonably possible in any area. The PMF is derived from the probable maximum precipitation (PMP) as determined on the basis of data obtained from the National Oceanographic and Atmospheric Administration (NOAA).
PROJECT SITE
The specific area of land where any regulated activities in the Township are planned, conducted, or maintained.
PUBLIC IMPROVEMENT
A street, sidewalk, walkway, gutter, curb, sewer, water line, streetlight, street sign or related facility to be dedicated to or maintained by the Township and which must comply with this Part.
PUBLIC UTILITY COMPANY
Any company subject to the jurisdiction of and control by the Pennsylvania Public Utility Commission or franchised cable television company.
QUALIFIED PROFESSIONAL
Any person licensed by the Pennsylvania Department of State or otherwise qualified by law to perform the work required by the ordinance.
RATIONAL FORMULA
A rainfall-runoff relation used to estimate peak flow.
RECORD DRAWING
A drawing that provides surveyed engineering data of constructed infrastructure.
REDEVELOPMENT
Earth disturbance activities on land that has previously been developed.
REGULATED ACTIVITIES
Any earth disturbance activities or any activities that involve the alteration or development of land in a manner that may affect stormwater runoff.
REGULATED EARTH DISTURBANCE ACTIVITY
Activity involving earth disturbance subject to regulation under 25 Pa. Code Chapter 92, Chapter 102, or the Clean Streams Law.[2]
RELEASE RATE DISTRICT
Those subwatershed areas in which post-development flows must be reduced to a certain percentage of predevelopment flows as required to meet the plan requirements and the goals of Act 167.
RETENTION BASIN
An impoundment in which stormwater is stored and not released during the storm event. Stored water may be released from the basin at some time after the end of the storm.
RETENTION VOLUME/REMOVED RUNOFF
The volume of runoff that is captured and not released directly into the surface waters of this commonwealth during or after a storm event.
RETURN PERIOD
The average interval, in years, within which a storm event of a given magnitude can be expected to recur. For example, the twenty-five-year return period rainfall would be expected to recur on the average of once every 25 years; or stated in another way, the probability of a twenty-five-year storm occurring in any one given year is 0.04 (i.e., a four-percent chance).
RIPARIAN BUFFER
A vegetated area bordering perennial and intermittent streams and wetlands that serves as a protective filter to help protect streams/wetlands from the impacts of adjacent land uses.
RISER
A vertical pipe extending from the bottom of a pond that is used to control the discharge rate from the pond for a specified design storm.
ROAD MAINTENANCE
Earth disturbance activities within the existing road right-of-way, such as grading and repairing existing unpaved road surfaces, cutting road banks, cleaning or clearing drainage ditches, and other similar activities. Road maintenance activities that do not disturb the subbase of a paved road (such as milling and overlays) are not considered earth disturbance activities.
ROOFTOP DETENTION
Temporary ponding and gradual release of stormwater falling directly onto flat roof surfaces by incorporating controlled-flow roof drains into building designs.
RUNOFF
Any part of precipitation that flows over the land surface.
RUNOFF CAPTURE VOLUME
The volume of runoff that is captured (retained) and not released into surface waters of the commonwealth during or after a storm event.
SEDIMENT
Soils or other materials transported by surface water as a product of erosion.
SEDIMENT BASIN
A barrier, dam, retention or detention basin located and designed to retain rock, sand, gravel, silt, or other material transported by stormwater runoff.
SEDIMENT POLLUTION
The placement, discharge, or any other introduction of sediment into waters of the commonwealth occurring from the failure to properly design, construct, implement or maintain control measures and control facilities in accordance with the requirements of this Part.
SEDIMENTATION
The process by which mineral or organic matter is accumulated or deposited by the movement of water.
SEEPAGE PIT/SEEPAGE TRENCH
An area of excavated earth filled with loose stone or similar coarse material into which surface water is directed for infiltration into the ground.
SEPARATE STORM SEWER SYSTEM
A conveyance or system of conveyances (including roads with drainage systems, Township streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains) primarily used for collecting and conveying stormwater runoff.
SHEET FLOW
Runoff that flows over the ground surface as a thin, even layer not concentrated in a channel.
SIDEWALK
A walk for pedestrians constructed to the standards set forth in this Part.
SOIL COVER COMPLEX METHOD
A method of runoff computation developed by the NRCS that is based on relating soil type and land use/cover to a runoff parameter called curve number (CN).
SPECIFICATIONS
Those portions of the contract documents consisting of written technical descriptions of materials, equipment, construction systems, standards and workmanship as applied to the work.
SPILLWAY (EMERGENCY)
A depression in the embankment of a pond or basin, or other overflow structure, that is used to pass peak discharges greater than the maximum design storm controlled by the pond or basin.
STATE WATER QUALITY REQUIREMENTS
The regulatory requirements to protect, maintain, reclaim, and restore water quality under Title 25 of that Pa. Code and the Clean Streams Law.
STORAGE INDICATION METHOD
A reservoir routing procedure based on solution of the continuity equation (inflow minus outflow equals the change in storage) with outflow defined as a function of storage volume and depth.
STORM FREQUENCY
The number of times that a given storm event occurs or is exceeded on the average in a stated period of years. See also "return period."
STORM SEWER
A system of pipes and/or open channels that convey intercepted runoff and stormwater from other sources, but excludes domestic sewage and industrial wastes.
STORMWATER
Runoff from the surface of the land resulting from precipitation, snow, or ice melt.
STORMWATER HOTSPOT
A land use or activity that generates higher concentrations of hydrocarbons, trace metals, or toxicants than are found in typical stormwater runoff.
STORMWATER MANAGEMENT FACILITIES
Any structure, natural or man-made, that due to its condition, design, or construction, conveys, stores, or otherwise affects stormwater runoff. Typical stormwater management facilities include, but are not limited to: detention and retention basins, open channels, storm sewers, pipes and infiltration facilities.
STORMWATER MANAGEMENT PLAN
The Butler County Stormwater Management Plan for managing stormwater runoff in Butler County as required by the Act of October 4, 1978, P.L. 864 (Act 167) and known as the "Storm Water Management Act."
STORMWATER MANAGEMENT SITE PLAN (SWM SITE PLAN)
The plan prepared by the applicant or his representative indicating how stormwater runoff will be managed at the project site in accordance with this Part.
STREAM ENCLOSURE
A bridge, culvert, or other structure in excess of 100 feet in length upstream to downstream which encloses regulated waters of the commonwealth.
STREET
An avenue, boulevard, road, highway, freeway, parkway, lane, viaduct and any other ways used by vehicular traffic, but not including driveways, parking areas or walkways. "Street" includes the entire right-of-way.
STREET EXCAVATION
Excavation of 18 inches or more performed within public rights-of-way or easements within the Township.
SUBWATERSHED AREA
The smallest drainage unit of a watershed for which stormwater management criteria has been established in the stormwater management plan.
SUBDIVISION
The division or redivision of a lot, tract or parcel of land by any means into two or more lots, tracts, parcels or other divisions of land, including changes in existing lot lines, for the purpose, whether immediate or future, of lease, partition by the court for distribution to heirs or devisees, transfer of ownership or building or lot development; provided, however, that the subdivision by lease of land for agricultural purposes into parcels of more than 10 acres, not involving any new street or easement of access or any residential dwelling, shall be exempted.
SUPERVISORS
The Board of Supervisors of the Township.
SWALE
A low-lying stretch of land that gathers or carries surface water runoff.
TEMPORARY ROADWAY
A roadway that is constructed for a defined amount of time to facilitate a construction activity.
TOWNSHIP
The Township of Cranberry, Butler County, Pennsylvania.
TIMBER OPERATIONS
See "forest management."
TIME OF CONCENTRATION (Tc)
The time for surface runoff to travel from the hydraulically most distant point of the watershed to a point of interest within the watershed. This time is the combined total of overland flow time and flow time in pipes or channels, if any.
UNDERGROUND BASIN
Detention storage located in underground tanks or vaults designed to provide water quantity control through detention of stormwater runoff.
USDA
The United States Department of Agriculture.
UTILITY
A public service including but not limited to electric service, gas service, and cable TV service.
WALKWAY
A walk for pedestrians constructed to the standards set forth in the Public Improvements Code.
WATERCOURSE
Includes all existing and proposed rivers, streams, creeks, runs, rivulets, channels, ditches, drains and drainage facilities which may flow continuously or flow intermittently during periods of wet weather or rain.
WATERS OF THE COMMONWEALTH
Rivers, streams, creeks, rivulets, impoundments, ditches, watercourses, storm sewers, lakes, dammed water, wetlands, ponds, springs and other bodies or channels of conveyance of surface and underground water, or parts thereof, whether natural or artificial, within or on the boundaries of the Commonwealth of Pennsylvania.
WATERSHED
Area drained by a river, watercourse, or other surface water, whether natural or artificial.
WETLAND
Those areas that are inundated or saturated by surface 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 and similar areas. (The term includes but is not limited to wetland areas listed in the State Water Plan, the United States Forest Service Wetlands Inventory of Pennsylvania and a wetland area designated by a river basin commission. This definition is used by the United States Environmental Protection Agency and the United States Army Corps of Engineers.)
WET POND
A basin that has a permanent pool of water throughout the year. A wet pond also may be called a "wet basin" or "retention pond."
[1]
Editor's Note: The definition of "flood fringe," which immediately followed this definition, was repealed 5/6/2015 by Ord. 2015-454.
[2]
Editor's Note: See 35 P.S. § 691.1 et seq.
[Ord. 2011-415, 5/5/2011, § 3]
1. 
Storm Sewer Pipe. A minimum fifteen-inch diameter pipe shall be installed for all storm sewers to be maintained by the Township. The following are acceptable pipes for use in the Township. All pipe shall meet appropriate AASHTO and ASTM standards.
[Amended by Ord. 2014-440, 1/30/2014]
A. 
Reinforced concrete pipe (RCP), Class III and Class IV.
B. 
Corrugated polyethylene (HDPE) culvert pipe and Type S.
C. 
Polyvinyl chloride (PVC) pipe.
D. 
Corrugated aluminum alloy pipe and corrugated aluminum coated pipe and pipe arch.
2. 
Storm Inlets. Storm inlets in street paving shall conform to the construction standard in SS-05, Type "M" Inlet Detail, when used with asphalt wedge curbs. Storm inlets in private developments that utilize concrete curbing and Type "C" inlet tops may utilize the construction standard in SS-06, Type "C" Inlet Detail. Storm inlets along streets that will be dedicated for public use shall conform to the construction standard in SS-06a, Concrete Curb Inlet Construction, when used with concrete curbs. Type "C" inlets shall not be used on streets dedicated for public use. Inlets shall be placed at all low points, at street intersections and at points along both sides of the street to ensure adequate drainage, but in no case shall the distance between inlets along the street exceed 300 feet unless approved by the Engineer. Inlets shall be installed at street intersections and shall be placed on the tangent and not on the curved portion. Additional inlets shall be constructed in areas as may be directed by the Engineer during construction to provide for proper control of surface water.
[Amended by Ord. 2014-440, 1/30/2014]
A. 
Inlet Grates.
(1) 
All grates on slopes less than 12% shall be bicycle-safe and constructed of steel and conform to the construction standards of SS-05B.
(2) 
All grates situated on roadways with a long grade steeper than 12% shall be constructed with a vane grate and shall conform to the construction standards of SS-05C.
B. 
Top Units (SS-05A). All tops shall be steel type M, unless otherwise approved by the Engineer. Units shall be constructed and conform to the construction standard in SS-05A.
C. 
Ladder bars shall be installed in all inlets exceeding a depth of five feet, and shall be in accordance with PennDOT Publication No. 72, Drawing RC-34. A poured concrete invert shall be formed in the base of all inlets to provide full drainage of the structure.
D. 
Inlets shall be specified as Type I-3 to meet maximum pipe outside diameters (O.D.) as set forth in PennDOT Publication 702, Drawing RC-34.
E. 
Type M Inlet Connections (SS-15). Any connection to an existing storm inlet shall be constructed and conform to the construction standard in SS-15. Any connection to an existing inlet must be approved by the Township in advance.
F. 
For inlets containing a change in pipe size, the elevation for the crown of the pipes shall be the same or the smaller pipe's crown shall be at a higher elevation.
G. 
All inlets shall provide a minimum two-inch drop between the lowest inlet pipe invert elevation and the outlet pipe invert elevation.
H. 
On curbed sections, a double inlet shall be placed at the low point of sag vertical curves, or an inlet shall be placed on each side of the low point at a distance not to exceed 100 feet, or at an elevation not to exceed 0.2 foot above the low point.
I. 
At all roadway low points, swales and easements shall be provided behind the curb or swale and through adjacent properties to channelize and direct any overflow of stormwater runoff away from dwellings and structures.
J. 
Inlets must be sized to accept the specified pipe sizes without knocking out any of the inlet corners. All pipes entering or exiting inlets shall be cut flush with the inside wall of the inlet. A note to this effect shall be added to the SWM site plan or inlet details therein.
K. 
Inlets shall have weep holes covered with geotextile fabric placed at appropriate elevations to completely drain the subgrade prior to placing the base and surface course on roadways.
L. 
Inlets shall not have a sump condition in the bottom (unless designed as a water quality BMP or specifically approved by the Township). Pipe shall be flush with the bottom of the box or concrete channels shall be poured.
M. 
Inlets shall not be leveled with bricks or wooden shims. Prior to final paving, a poured in-place riser shall be constructed in accordance with Detail SS-25, Poured Concrete Riser.
3. 
Storm Manholes. All manholes shall be precast concrete constructed in accordance with the construction standards in SS-08, Typical Storm Sewer Manhole, and Figure SS-07, Standard Manhole Frame and Cover. Manholes shall be installed at all changes in alignment and grades of storm sewers as may be directed by the Engineer to provide for proper maintenance. If maintenance is not a problem, pipe may be installed on a curve, provided that the deflection angle of the pipe joint does not exceed the manufacturer's specifications. See SS-09 for pipes under 48 inches in diameter and SS-10 for pipes over 48 inches in diameter. Inlets may be substituted for manholes where practical.
4. 
Maximum Distance Between Structures. The maximum distance between structures (inlets or manholes) shall be 300 feet unless otherwise approved by the Engineer.
A. 
Yard Drains (rev. 2/01) SS-11. Yard drains shall be precast concrete constructed in accordance with the construction standards in SS-11. The top unit may be substituted with Type M tops, if approved by the Engineer.
B. 
Special Underdrains (rev. 1101) (SS-12). Underdrains shall be installed in accordance with the standard in SS-12. The underdrain type shall be directed by the Engineer.
5. 
Inlet Connections (SS-03). All connections to Type C inlets shall be in accordance with SS-03.
6. 
Storm Sewer Lateral Connection. All sewer lateral connections shall be in accordance with applicable law. All sewer lateral connections shall be located at manholes, catch basins, or at locations approved by the Township Engineer or his designated representative.
A. 
All storm sewer laterals or runs designed to collect and/or connect to individual residential lot roof drains shall be smooth-lined HDPE (high-density polyethylene pipe).
7. 
Township Design Requirements for Stormwater Management.
A. 
General Requirements.
(1) 
The design criteria are intended to elaborate on Township ordinances such as Part 5, Required Improvements, and Part 6, Design Standards, of the Subdivision and Land Development Ordinance [Chapter 22] and to complement the Storm Water Management Act, P.L. 864, No. 167, 32 P.S. § 680.1 et seq. Said Act requires that actions be taken:
(a) 
To assure that the maximum rate of stormwater runoff is no greater after development than prior to development activities.
(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.
(c) 
To comply with federal and state regulations to implement a program of stormwater controls. The Township is required to obtain a federal permit for stormwater discharges from its separate storm sewer systems under the National Pollutant Discharge Elimination System (NPDES).
(d) 
To utilize and preserve the desirable existing natural drainage systems and to preserve the flood-carrying capacity of streams; to maintain existing flows and quality of streams and watercourses.
(e) 
To encourage natural infiltration of rainfall to preserve groundwater supplies and streamflows.
1) 
Minimization of impervious surfaces and infiltration of runoff through seepage beds, infiltration trenches, etc., are encouraged, where soil conditions and geology permit, to reduce the size or eliminate the need for detention facilities.
2) 
Infiltration BMPs should be dispersed throughout the site, made as shallow as practicable, and located to maximize use of natural on-site infiltration features while still meeting the other requirements of this Part.
(f) 
To implement an illegal discharge detection and elimination program to address non-stormwater discharges into the Township's separate storm sewer system.
(2) 
Stormwater management design and construction will conform in general to the applicable recognized national and state acts, manuals, and references such as the Pennsylvania Storm Water Management Act, 32 P.S. § 680.1 et seq., and PennDOT published forms.
(3) 
The SWM site plan approved by the Township shall be on site throughout the duration of the regulated activities.
(4) 
Applicants are encouraged to use low-impact development practices to reduce the costs of complying with the requirements of this Part and the State Water Quality Requirements.
(5) 
When stormwater management facilities are proposed within 1,000 feet of a downstream township, the developer shall notify the downstream township and provide a copy of the SWM plan, if requested, for review and comment.
(6) 
A copy of the approved erosion and sediment control plan and any other permit, as required by PADEP or the Butler County Conservation District, shall be available at the project site at all times if required under Chapter 102.
(7) 
All stormwater management plans shall be designed and certified by individuals registered in the Commonwealth of Pennsylvania and qualified to perform such duties.
(8) 
Where applicable, stormwater management facilities shall comply with the requirements of 25 Pa. Code, Chapter 105, Dam Safety and Waterway Management, and § 404 of the Clean Water Act as authorized by the United States Corps of Engineers. All regulated earth disturbance activities are subject to permit requirements by DEP under regulations at 25 Pa. Code, Chapter 102. When there is a question whether wetlands may be involved, it is the responsibility of the applicant or his agent to show that the land in question cannot be classified as wetlands; otherwise, approval to work in the area must be obtained from PADEP. The applicant shall meet requirements as contained in 25 Pa. Code, Chapters 92 and 102, as required and applicable as follows:
(a) 
The implementation and maintenance of erosion and sediment control BMPs.
(b) 
Development of written plans.
(c) 
Submission of plans for approval.
(d) 
Obtaining erosion and sediment control and NPDES permits.
(e) 
Maintaining plans and permits on site.
(9) 
Stormwater management facilities that may impact a state highway shall be subject to the approval of the Pennsylvania Department of Transportation.
(10) 
Stormwater runoff from a project site shall flow directly into a natural watercourse or into an existing storm sewer system or onto adjacent properties in a manner similar to the runoff characteristics of the predevelopment flow. All natural streams, channels, swales, drainage systems and/or areas of surface water connection shall be maintained in their existing condition unless an alteration is approved by the Township. All encroachment activities shall comply with the requirements of 25 Pa. Code, Chapter 105, Dam Safety and Waterway Management.
(a) 
If diffused flow is proposed to be concentrated and discharged onto adjacent property, the applicant must document that adequate downstream conveyance facilities exist to safely transport the concentrated discharge, or otherwise prove that no erosion, sedimentation, flooding, or other harm will result from the concentrated discharge.
1) 
The applicant must provide an easement for proposed concentrated flow across adjacent properties to a drainageway or public right-of-way.
2) 
Such stormwater flows shall be subject to the requirements of this Part.
(11) 
Stormwater runoff shall not be transferred from one watershed to another unless the watersheds are subareas of a larger watershed that are tributary to a common point of interest within or near the perimeter of the property. Transfer of runoff from one watershed to another under any other circumstances shall only be approved at the discretion of the Township. Documentation shall be provided that peak flow rates are not increased following development and there will be no detrimental impact in downstream areas.
(12) 
All stormwater runoff flowing over the project site shall be considered in the design of the stormwater management facilities.
(13) 
For any stormwater management facility requiring a permit to be issued by PADEP, said permit along with supporting report and plans used to secure the permit shall also be submitted.
B. 
Stormwater Management Standards.
[Amended by Ord. 2014-440, 1/30/2014]
(1) 
Design Storms. Stormwater management facilities on all development sites shall control the peak stormwater discharge for the one- , two- , ten- , twenty-five- , fifty- , and one-hundred-year design storms. SCS twenty-four-hour, Type II rainfall distribution shall be used in conjunction with rainfall depths from NOAA Atlas 14 for analyzing stormwater runoff in pre- and post-development conditions, as well as for designing runoff control facilities, except as noted in § 17-350.7B(2)(b). The rainfall data to be used for SCS TR-55 computations in Cranberry Township are:
Design Storm Return Period
24-Hour Rainfall Depth
(inches)
1-year
2.02
2-year
2.41
10-year
3.38
25-year
4.00
50-year
4.50
100-year
5.03
All calculations shall be consistent with guidelines set forth in the BMP Manual. The Pennsylvania Department of Transportation Drainage Manual, Intensity-Duration-Frequency Curves, Publication 584, Chapter 7A, latest edition, shall be used in conjunction with the appropriate time of concentration and return period to determine the rainfall intensity in inches per hour. (For additional information or data on other return periods, consult the Rainfall Duration Frequency Tables for Pennsylvania, produced by PADEP, Office of Resource Management, Bureau of Dams and Waterways Management, Division of Stormwater Management, Harrisburg, February 1983, or in its most recent update.)
(2) 
Calculation Methods.
(a) 
Development Sites. For the purposes of computing peak flow rates, runoff hydrographs, and storage requirements for development sites, either the NRCS Rainfall-Runoff Method as presented in the most recent version of Technical Release 55 (TR-55) shall be used, or the Rational Method as specified in § 17-350.7B(1). When the Rational Method is used, the technical data in Appendix 17-A[1] shall be used to determine rainfall intensities, time of concentration, and runoff coefficients. The use of alternative hydrologic methodologies may be approved by the Township if sufficient justification and documentation of their application is provided.
1) 
The Rational Method shall not be used to calculate runoff volume.
1.1) 
Rational Method. This method may be used for design of conveyance facilities only. Extreme caution should be used by the design professional if the watershed has more than one main drainage channel, if the watershed is divided so that hydrologic properties are significantly different in one portion versus the other, if the time of concentration exceeds 60 minutes or if stormwater runoff volume is an important factor. The combination of Rational Method hydrographs based on timing shall be prohibited.
2) 
NRCS Rainfall-Runoff Method. This method shall be used to estimate the change in volume due to regulated activities. Combining curve numbers for land areas proposed for development with curve numbers for areas unaffected by the proposed development into a single weighted curve number is not acceptable.
3) 
NRCS Rainfall-Runoff Method. This method is recommended for design of stormwater management facilities and where stormwater runoff volume must be taken into consideration. The following provides guidance on the model applicability:
a) 
NRCS's TR-55: limited to 100 acres in size.
b) 
NRCS's TR-20, WinTR-20, WinTR-55, HEC-HMS: no watershed size limitations.
c) 
The NRCS antecedent runoff condition II (ARC II, previously AMC II) must be used for all simulations. The use of continuous simulation models that vary the ARC are not permitted for stormwater management purposes.
d) 
For comparison of peak flow rates, flows shall be rounded to a tenth of a cubic foot per second (cfs).
4) 
The time of concentration is to represent the average condition that best reflects the hydrologic response of the area. The following time of concentration (Tc) computational methodologies shall be used unless another method is preapproved by the Township Engineer:
a) 
Predevelopment — NRCS's Lag Equation:
Time of Concentration = Tc = [(Tlag/.6) * 60] (minutes)
Where
Tlag = Lag time (hours).
L = Hydraulic length of watershed (feet).
Y = Average overland slope of watershed (percent).
S = Maximum retention in watershed as defined by: S = [(1,000/CN) — 10].
CN = NRCS curve number for watershed.
b) 
Post-development; commercial, industrial, or other areas with large impervious areas (greater than 20% impervious area): NRCS Segmental Method. The length of sheet flow shall be limited to 100 feet. Tc for channel and pipe flow shall be computed using Manning's equation.
c) 
Post-development; residential, cluster, or other low-impact designs less than or equal to 20% impervious area: NRCS Lag Equation or NRCS Segmental Method.
5) 
Additionally, the following provisions shall apply to calculations for time of concentration:
a) 
The post-development Tc shall never be greater than the predevelopment Tc for any watershed or subwatershed. This includes when the designer has specifically used swales to reduce flow velocities. In the event that the designer believes that the post-development Tc is greater, it will still be set by default equal to the predevelopment Tc for modeling purposes.
b) 
The minimum Tc for any watershed shall be five minutes.
c) 
The designer may choose to assume a five-minute Tc for any post-development watershed or subwatershed without providing any computations.
d) 
The designer must provide computations for all predevelopment Tc paths. A five-minute Tc cannot be assumed for predevelopment.
e) 
Undetained fringe areas (areas that are not tributary to a stormwater facility but where a reasonable effort has been made to convey runoff from all new impervious coverage to best management practices) may be assumed to represent the predevelopment conditions for purpose of Tc calculation.
6) 
In addition to § 17-350.7.B(2)(a) and (b), stormwater runoff volume controls shall be implemented using the Design Storm Method or the Simplified Method as defined below. For regulated activity areas equal to or less than one acre that do not require hydrologic routing to design the stormwater facilities, this Part establishes no preference for either method; therefore, the applicant may select either method on the basis of economic considerations, the intrinsic limitations on applicability of the analytical procedures associated with each methodology, and other factors.
a) 
The Design Storm Method (CG-1 in the BMP Manual) is applicable to any sized regulated activity. This method requires detailed modeling based on site conditions.
i. 
Do not increase the post-development total runoff volume when compared to the predevelopment total runoff volume for the two-year/twenty-four-hour storm event.
ii. 
For hydrologic modeling purposes:
[A]
Existing nonforested pervious areas must be considered meadow (good condition) for predevelopment hydrologic calculations.
[B]
Twenty percent of existing impervious area, when present within the proposed project site, shall be considered meadow (good condition) for predevelopment hydrologic calculations for redevelopment.
b) 
The Simplified Method (CG-2 in the BMP Manual) is independent of site conditions and should be used if the Design Storm Method is not followed. This method is not applicable to regulated activities greater than one acre or for projects that require detailed design of stormwater storage facilities. For new impervious surfaces:
i. 
Stormwater facilities shall capture at least the first two inches of runoff from all new impervious surfaces.
ii. 
At least the first one inch of runoff from new impervious surfaces shall be permanently removed from the runoff flow, i.e., it shall not be released into surface waters of the commonwealth. Removal options include reuse, evaporation, transpiration, and infiltration.
iii. 
Wherever possible, infiltration facilities should be designed to accommodate infiltration of the entire permanently removed runoff; however, in all cases at least the first 0.5 inch of the permanently removed runoff should be infiltrated.
iv. 
Actual field infiltration tests at the location of the proposed elevation of the stormwater BMPs are required. Infiltration tests shall be conducted in accordance with the BMP Manual. Notification of the Township shall be provided to allow witnessing of the testing.
c) 
In cases where it is not possible or desirable to use infiltration-based best management practices to partially fulfill the requirements in either § 17-350, Subsection 7B(2)(a)6)a) or b), the following procedure shall be used:
i. 
At a minimum, the following documentation shall be provided to justify the decision to not use infiltration BMPs:
[A]
Description of and justification for field infiltration/permeability testing with respect to the type of test and test locations.
[B]
An interpretive narrative describing existing site soils and their structure as these relate to the interaction between soils and water occurring on the site. In addition to providing soil and soil profile descriptions, this narrative shall identify depth to seasonal high water tables and depth to bedrock, and provide a description of all subsurface elements (fragipans and other restrictive layers, geology, etc.) that influence the direction and rate of subsurface water movement.
[C]
A qualitative assessment of the site's contribution to annual aquifer recharge shall be made, along with identification of any restrictions or limitations associated with the use of engineered infiltration facilities.
[D]
The provided documentation must be signed and sealed by a professional engineer or geologist.
ii. 
The following water quality pollutant load reductions will be required for all disturbed areas within the proposed development:
Pollutant Load
Units
Required reduction
Total suspended solids (TSS)
Pounds
85%
Total phosphorous (TP)
Pounds
85%
Total nitrate (NO3)
Pounds
50%
iii. 
The performance criteria for water quality best management practices shall be determined from the Pennsylvania Stormwater Best Management Practices Manual, most current version.
7) 
The applicable worksheets from the BMP Manual must be used in calculations to establish volume control.
[1]
Editor's Note: Appendix 17-A is included as an attachment to this chapter.
(b) 
Stormwater Collection/Conveyance Facilities. For the purpose of designing storm sewers, open swales and other stormwater runoff collection and conveyance facilities, the Rational Method shall be utilized employing the technical data referenced in § 17-350.7B(2)(a). The design storm for storm sewers and swales that will discharge to detention facilities is the one-hundred-year storm. The ten-year design storm for storm systems discharging to detention facilities shall be acceptable, provided that it can be documented that runoff exceeding the ten-year capacity of the storm system during a one-hundred-year storm event will ultimately discharge to the detention facility by alternative means, without endangering public safety or damaging private property. The design storm for all other on-site storm sewers or swales is the ten-year storm event, provided that larger storm events will not impact private property.
1) 
All stormwater collection and/or conveyance systems routing water through or around the development site shall be designed for the one-hundred-year storm event, unless it can be documented that said facilities will not create a hazard.
2) 
A drainage easement shall be provided to contain and convey the one-hundred-year flood event throughout the project site, beginning at the furthest upstream property line of the proposed development in the watershed. Where watercourses traverse a development site, drainage easements (with a minimum width of 20 feet and including the one-hundred-year water surface) shall be provided conforming to the line of such watercourses. The terms of the easement shall prohibit excavation, the placing of fill or structures, and any alterations that may adversely affect the flow of stormwater within any portion of the easement. Also, maintenance, including mowing of vegetation within the easement, may be required, except as approved by the appropriate governing authority.
3) 
The Rational Method may be used for design of conveyance facilities only. Extreme caution should be used by the design professional if the watershed has more than one main drainage channel, if the watershed is divided so that hydrologic properties are significantly different in one versus the other, if the time of concentration exceeds 60 minutes, or if stormwater runoff volume is an important factor. The combination of Rational Method hydrographs based on timing shall be prohibited.
4) 
All structures (culverts or bridges) proposed to convey runoff under a Township road shall be designed to pass the fifty-year design storm with a minimum one foot of freeboard measured below the lowest point along the top of the roadway.
(c) 
Stormwater Management Facilities. Peak runoff rates for all on-site areas and off-site areas impacting the project site shall be determined and considered in the design of stormwater management facilities. These calculations shall be based on land use, time of concentration and other standard hydrologic parameters as noted in § 17-350.7B(2)(a).
(d) 
All calculations shall be consistent with the guidelines set forth in the BMP Manual, as amended herein.
(e) 
Impervious Areas:
1) 
The measurement of impervious areas shall include all of the impervious areas in the total proposed development, even if development is to take place in stages.
2) 
For developments taking place in stages, the entire development plan must be used in determining conformance with this Part.
(3) 
Cranberry Township HEC-1 Watershed Model. All proposed subdivision and land developments employing stormwater management facilities designed to control five acres or more of watershed area, or less at the Township's discretion, shall be analyzed by the Township with the Cranberry Township HEC-1 Watershed Model. The resulting impacts in downstream areas associated with the watershed modeling shall be the determining factor for approval of proposed stormwater management plans.
(4) 
Performance Standards.
(a) 
Where, in the judgment of the Township, the additional volume or peak flow of stormwater runoff associated with a proposed development site will have a detrimental impact on downstream properties or drainage structures and/or on existing documented downstream flooding concerns, post-development peak flows may be required to be reduced to less than otherwise determined site allowable release rates [§ 17-350.7B(4)(e)]. Under these circumstances, acceptable peak flow rates will be determined at the discretion of the Township for a given storm event(s) based on existing downstream restrictions. Additional hydrologic studies or analyses may also be required. Alternative mitigation measures in lieu of increased peak flow reduction may be considered by the Township on a case-by-case basis.
(b) 
Release Rate Percentage (RR%).
1) 
The release rate percentage defines the percentage of the predevelopment peak rate of runoff that can be discharged from the site following development as determined in the Cranberry Township Stormwater Management Plan. As per the plan, the Township shall be divided into three separate watersheds as noted below.
a) 
Brush Creek Watershed.
b) 
Wolfe Run Watershed.
c) 
Kaufman Run Watershed.
2) 
These watersheds are further subdivided into subwatersheds of similar hydrologic characteristics upon which release rate percentages for each subwatershed are determined. All subdivisions and land developments located in these subwatersheds that result in an increase in site runoff following development shall use the release rate percentages designated on the Release Rate Percentage Map in Appendix 17-C[2] as a guideline to determine allowable release rates [§ 17-350.7.B(4)(e)] for the development site.
[2]
Editor's Note: Appendix 17-C is included at the end of this chapter.
(c) 
The following sites may be exempted from the designated release rate percentage upon approval by the Township.
1) 
Development sites comprising three acres or less located in a subwatershed with a designated release rate percentage of less than 100% shall employ a release rate of 100% to determine the site's allowable release rate, provided that conditions cited in § 17-350.7B(4)(a), are not evident in downstream areas.
2) 
Development sites where application of the designated release rate percentage may induce significant economic or site layout constraints may request a modification of the designated release rate percentage. Under these circumstances, the developer shall submit a proposed stormwater management plan with sufficient detail for the Township to evaluate the impact of the development with the Township HEC-1 Watershed Model [§ 17-350.7B(3)]. The Township shall approve or disapprove the proposed plan based on the resulting impacts in downstream areas indicated by the watershed model. Based on the watershed analysis, the following procedures shall be followed at the discretion of the Township.
a) 
The developer shall submit a revised stormwater management plan reducing peak flow rates to a level acceptable to the Township on the basis of the evaluation with the Township HEC-1 Watershed Model. With the exception of provisions noted in § 17-350.7B(4)(a), the maximum reduction that may be imposed on a site is the designated release rate percentage as per the Release Rate Percentage Map (Appendix 17-C).[3]
[3]
Editor's Note: Appendix 17-C is included at the end of this chapter.
b) 
The Township may approve the developer's plan, provided that the Township HEC-1 Watershed Model shows minimal impact at any point downstream that may result from runoff associated with the proposed development site. This approval shall be evaluated by the Township on the basis of numerous factors, including watershed location, erosional concerns and provisions cited in § 17-350.7B(4)(a).
(d) 
Predevelopment Conditions. The cover type(s) for all sites shall be consistent with site conditions based on aerial photography of the Township dated May 27, 1999, and employed in the watershed models developed for the Cranberry Township Stormwater Management Plan. These cover types shall be field verified, and the runoff curve numbers (RCN) presented in Table 1 shall be used to determine predevelopment peak flow rates when employing the SCS TR-55 Soil Complex Methodology.
1) 
For the purposes of predevelopment peak flow rate and volume determination, existing nonforested pervious areas conditions shall be considered as meadow (good condition).
2) 
For the purposes of predevelopment peak flow rate and volume determination, 20% of existing impervious area, when present, shall be considered meadow (good condition).
Table 1
SCS Runoff Curve Number (RCN)
Cover Type
Hydrologic Soil Group
B
C
D
Woods
55
70
77
Meadow (good condition)
58
71
78
3) 
The runoff coefficients (c) to be employed with the Rational Formula for these cover types shall be consistent with the table provided in Appendix 17-A.[4]All hydrologic parameters used to calculate peak flow rates shall use the appropriate coefficients pertaining to these conditions as noted in § 17-350.7B(2)(a).
[4]
Editor's Note: Appendix 17-A is included as an attachment to this chapter.
(e) 
Allowable Release Rates. The allowable release rates from stormwater management facilities, or a development site in general, shall be less than or equal to the predevelopment peak runoff rates generated for the site. All stormwater runoff discharged from the site that is not controlled by a stormwater management facility shall be accounted for in the determination of the allowable release rates for the full range of storm events. The allowable release rate (RR) for a site as per § 17-350.7B(4)(b), shall be determined by the following equation for each design storm event:
Predevelopment Peak Flow Rate x RR%/100 = Allowable RR
(f) 
Post-Development Conditions. The hydrologic parameters used to develop peak flow rates shall be reflective of anticipated soil runoff characteristics following grading operations of the site, with areas disturbed by heavy machinery associated with topsoil stripping, excavation and engineered fill modeled as meadow (good condition) with Hydrologic Soil Group D characteristics as per Table 1 of § 17-350.7B(4)(d).
(g) 
Redevelopment Sites. Existing sites proposed for redevelopment that currently provide no stormwater management, and/or sites that will remove existing or inadequate stormwater management facilities, shall provide stormwater management as per § 17-350.7B. For the purposes of determining predevelopment peak flow rates, the developed site shall be considered as meadow (good condition) with Hydrologic Soil Group D characteristics as per Table 1 of § 17-350.7B(4)(d), or a weighted runoff coefficient of existing cover types should that yield lower coefficient values.
(5) 
The low-impact development practices provided in the BMP Manual, as may be amended from time to time, said amendments incorporated herein by reference, and in the Operation and Maintenance Agreement, in form and substance approved by the Township Solicitor and the Board of Supervisors, of Chapter 17 shall be utilized for all regulated activities to the maximum extent practicable.
(6) 
Drainage areas tributary to sinkholes or closed depressions in areas underlain by limestone or carbonate geologic features shall be excluded from the modeled point of analysis defining predevelopment flows. If left undisturbed during construction activities, areas draining to closed depressions may also be used to reduce peak runoff rates in the post-development analysis. New, additional contributing runoff should not be directed to existing sinkholes or closed depressions.
(7) 
Where uniform flow is anticipated, the Manning's equation shall be used for hydraulic computations and to determine the capacity of open channels, pipes, and storm sewers. The Manning's equation should not be used for analysis of pipes under pressure flow or for analysis of culverts. Manning's "n" values shall be obtained from PennDOT's Drainage Manual, Publication 584. Inlet control shall be checked at all inlet boxes to ensure the headwater depth during the ten-year design event is contained below the top of grate for each inlet box.
(8) 
The Township has the authority to require that computed existing runoff rates be reconciled with field observations, conditions and site history. If the designer can substantiate, through actual physical calibration, that more appropriate runoff and time of concentration values should be utilized at a particular site, then appropriate variations may be made upon review and recommendation of the Township.
C. 
Stormwater Management Plan.
(1) 
General Requirements.
(a) 
No final subdivision or 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. The design of all stormwater management facilities shall incorporate sound engineering principles and practices. The Township shall reserve the right to disapprove any design that would result in the continuation or exacerbation of a documented adverse hydrologic or hydraulic condition within the watershed, as identified in the plan.
(b) 
A letter from the Butler County Conservation District approving the erosion and sedimentation control plan must also be received prior to the initiation of any grading. In the event that submission to the Butler County Conservation District is not required by the Township, an erosion and sediment pollution control plan prepared in accordance with the most recent version of PADEP Chapter 102, Erosion and Sedimentation Control Program Manual, must be approved by the Township.
(c) 
Exemptions.
1) 
The following activities are specifically exempt from this Part.
a) 
Use of land for gardening primarily for home consumption.
b) 
Use of land for construction of landscaping improvements, provided that such improvements do not significantly alter the runoff characteristics for the land.
c) 
Agricultural use of lands when operated in accordance with a farm conservation plan approved by the local soil conservation district, or when it is determined by the local soil conservation district that such use will not cause excessive erosion and sedimentation. Agricultural activities are exempt from the rate control and SWM site plan preparation requirements of this Part, provided that the activities are performed according to the requirements of 25 Pa. Code Chapter 102.
2) 
Under no circumstance shall the applicant be exempt from implementing such measures as necessary to:
a) 
Meet state water quality standards and requirements.
b) 
Protect health, safety, and property.
c) 
Meet special requirements for High-Quality (HQ) and Exceptional Value (EV) watersheds.
3) 
The applicant must demonstrate that the following BMPs are being utilized to the maximum extent practicable to receive consideration for the exemptions:
a) 
Design around and limit disturbance of floodplains, wetlands, natural slopes over 15%, existing native vegetation, and other sensitive and special value features.
b) 
Maintain riparian and forested buffers.
c) 
Limit grading and maintain nonerosive flow conditions in natural flow paths.
d) 
Maintain existing tree canopies near impervious areas.
e) 
Minimize soil disturbance and reclaim disturbed areas with topsoil and vegetation.
f) 
Direct runoff to pervious areas.
4) 
The applicant must demonstrate that the proposed development/additional impervious area will not adversely impact the following:
a) 
Capacities of existing drainageways and storm sewer systems.
b) 
Velocities and erosion.
c) 
Quality of runoff if direct discharge is proposed.
d) 
Existing known problem areas.
e) 
Safe conveyance of the additional runoff.
f) 
Downstream property owners.
5) 
An applicant proposing regulated activities may be eligible for exemption from rate control, volume control, or stormwater management site plan requirements in this Part according to the following table:
Table 350.7C5
Exemptions and Submission Requirements
New Impervious Area1, 2
(square footage)
Applicant Must Provide
0 to less than 2,500
No submission is required
2,500 to less than 5,000
Documentation of new impervious surfaces3
5,000 and greater
Rate controls, volume controls and SWM site plan
NOTES:
1
New impervious area since the date of adoption of this Part.
2
Gravel in existing condition shall be considered pervious and gravel in proposed condition shall be considered impervious.
3
The small project stormwater management application in form and substance approved by the Township Solicitor and the Board of Supervisors shall be used to document new impervious surfaces.
6) 
Single-family residential activities are exempt from these requirements, provided that the construction:
a) 
Complies with §§ 17-350.7C(1)(c)8), 17-350.7C(1)(c)2), 17-350.7C(1)(c)3), and 17-350.7C(1)(c)4); and
b) 
Has building setback 75 feet from downstream property lines; and
c) 
Driveways:
i. 
Runoff must discharge onto pervious surface with a gravel strip or other spreading device.
ii. 
No more than 1,000 square feet of paved surface may discharge to any one point.
iii. 
The length of flow on the pervious surface must exceed the length of the paved surface flow.
d) 
The Township can require more information or require mitigation of certain impacts through installation of stormwater management BMPs if there is a threat to property, health, or safety.
7) 
An applicant proposing regulated activities, after demonstrating compliance with §§ 17-350.7C(1)(c)2), 17-350.7C(1)(c)3), and 17-350.7C(1)(c)4) may be exempted from various requirements of this Part if documentation can be provided that a downstream man-made water body (i.e., reservoir, lake, or man-made wetlands) has been designed or modified to address the potential stormwater flooding impacts of the proposed development.
8) 
The purpose this section is to ensure consistency of stormwater management planning between local ordinances and NPDES permitting (when required) and to ensure that the applicant has a single and clear set of stormwater management standards to which the applicant is subject. The Township may accept alternative stormwater management controls under this section, provided that:
a) 
The Township, in consultation with the PADEP (or delegated authority), determines that meeting the volume control requirements [See § 17-350.7B(2)(a)6).] is not possible or places an undue hardship on the applicant.
b) 
The alternative controls are documented to be acceptable to PADEP (or delegated authority) for NPDES requirements pertaining to post-construction stormwater management requirements.
c) 
The alternative controls are in compliance with all other sections of this Part, including but not limited to §§ 17-350.7A(1)(c), 17-350.7C(1)(c)8), 17-350.7C(1)(c)2), 17-350.7C(1)(c)3), and 17-350.7C(1)(c)4).
9) 
Forest management and timber operations are exempt from the rate and volume control requirement and SWM site plan preparation requirement of this Part, provided that the activities are performed according to the requirements of 25 Pa. Code Chapter 102. It should be noted that temporary roadways are not exempt.
10) 
The Township may deny or revoke any exemption pursuant to this section at any time for any project that the Township believes may pose a threat to public health, safety, property or the environment.
11) 
Small Developments. A "small development" shall be defined as a site that creates less than 5,000 square feet of impervious surface, and shall be exempt from the preparation of a detailed stormwater management plan as specified in § 17-350.7C. However, such developments must still provide safe management of stormwater runoff in accordance with the performance standards specified in § 17-350.7B of this Part and as approved by the Township.
a) 
Applications for small developments shall include a plan that describes, narratively and graphically, the type and location of proposed on-site stormwater management techniques or the proposed connection to an existing storm sewer system.
b) 
Runoff calculations, as required at the discretion of the Township, shall be prepared in accordance with § 17-350.7B(6).
c) 
The Township shall review and approve the proposed provisions for stormwater management for a small development.
d) 
Under the appropriate circumstances, the Township may waive stormwater management requirements required per § 17-350.7B(1), provided that it is documented that no detrimental impacts associated with erosion or capacity of storm structures will occur in downstream locations. Design provisions to effectively manage stormwater runoff discharged from the site shall be required.
12) 
Proposed impervious surfaces (structures, roads, paved areas and buildings) shall include plans and profiles of roads and paved areas and floor elevations of buildings.
[Added by Ord. 2014-440, 1/30/2014]
(2) 
Stormwater Management Report. A written and bound report shall be submitted, including, but not necessarily limited to, the following information:
(a) 
Proposed name or identifying title of project, the name and address of the landowner and developer of the project site, as well as the name, address, and phone number of the consultant who prepared the stormwater management plan.
(b) 
Stormwater management report date and date of the latest revision to the report.
(c) 
Typewritten narrative report that should include sections describing the following items:
1) 
Stormwater management plan objectives. Statement of the regulated activity describing what is being proposed. Overall stormwater management concept with description of permanent stormwater management techniques, including construction specifications and materials to be used for stormwater management facilities.
2) 
Hydrologic procedures used to develop plan.
3) 
Description(s) of predevelopment watershed conditions.
4) 
Description(s) of post-development watershed conditions.
5) 
Descriptions of proposed plan and methods to handle post-development runoff.
6) 
Description(s) of proposed detention facility(s) and proposed outlet control.
7) 
Summary tables for:
a) 
Predevelopment Hydrologic Soil Group (HSG) assumptions, curve numbers (CN), computation of average slope, hydraulic length, computed time of concentration.
b) 
Existing conditions runoff volume and peak rate of runoff.
c) 
Post-development runoff volume and peak rate of runoff.
d) 
Undetained areas; areas to ponds.
e) 
Land use for each subarea.
f) 
Hydrologic Soil Group (HSG) assumptions, curve numbers (CN).
g) 
Time of concentration computed for each subarea.
h) 
Post-development peak rate of runoff routed to ponds and out.
i) 
Pond maximum return period design data, including: maximum water surface elevation, berm elevation, and emergency spillway elevation.
j) 
Water quality depth and volume requirements.
8) 
Soil names and boundaries with identification of the Hydraulic Soil Group classification, including rock outcroppings.
9) 
Expected project schedule.
10) 
Location map showing the project site and its location relative to release rate districts.
11) 
Detailed description of the existing site conditions, including a site evaluation completed for projects proposed in areas of carbonate geology or karst topography and other environmentally sensitive areas such as brownfields.
12) 
Total site area pre- and post-, which must be equal or have an explanation as to why it is not.
13) 
Total site impervious area.
14) 
Total off-site areas.
15) 
Number and description of stormwater management facilities.
16) 
Whether the site is a water quality sensitive (WQS) development.
17) 
Whether the site is in a defined sensitive area.
18) 
Types of water quality and recharge systems used, if applicable.
19) 
Other pertinent information, as required.
20) 
Reports that do not clearly indicate the above information may be rejected for review by the Township and will be returned to the applicant.
21) 
The effect of the project (in terms of runoff volumes, water quality, and peak flows) on surrounding properties and aquatic features and on any existing Township stormwater collection system that may receive runoff from the project site.
22) 
Description of the proposed changes to the land surface and vegetative cover, including the type and amount of impervious area to be added.
(d) 
Watershed maps delineating predevelopment and post-development watershed boundaries, as well as the flow path and segments used to determine time of concentrations for each watershed. The Chapter 93 watershed and discharge waterway classification (CWF, TSF, etc.) must also be included on the plan.
(e) 
All hydrologic, hydraulic, and structural computations, calculations, assumptions, and criteria associated with the stormwater management plan, appended and referenced in the narrative.
1) 
Details of the berm embankment and outlet structure indicating the embankment top elevation, embankment side slopes, top width of embankment, emergency spillway elevation, perforated riser dimensions, pipe barrel dimensions and dimensions and spacing of antiseep collars.
2) 
Design computations for the control structures (pipe barrel and riser, etc).
3) 
A plot or table of the stage-storage (volume vs. elevation) and all supporting computations.
4) 
Routing computations.
(f) 
Storm sewer calculations and watershed map delineating all subareas used to size and compute flows for the storm sewer system.
(g) 
Operation and Maintenance Program. The report shall contain a proposed maintenance plan for all stormwater control facilities, in accordance with the following:
1) 
Identify the proposed ownership entity (e.g., Township, property owner, homeowners' association, other management entity) and maintenance responsibility for all permanent stormwater management facilities.
2) 
A maintenance program for all facilities that outlines the anticipated maintenance tasks, required inspection, frequencies and inspection guidelines. Provisions for scheduled vegetation maintenance for open facilities shall be included to prevent overgrowth from limiting proper operation and inspection of the facility(s).
3) 
Include a maintenance program for all post-construction stormwater BMPs, outlining the type of maintenance activities, probable frequencies, personnel and equipment requirements, and estimated annual maintenance costs. The maintenance program shall include specific requirements for during construction and for after construction.
4) 
Identify the method of financing for continuing operation and maintenance of the facility.
5) 
The owner is responsible for operation and maintenance of the stormwater BMPs. If the owner fails to adhere to the operation and maintenance (O&M) agreement, the Township may perform the services required and charge the owner appropriate fees. Nonpayment of fees may result in a lien against the property. A note shall be placed on the recorded plan: "As per the approved stormwater management plan, the Township shall have right of access to the on-site detention facility for the right of maintenance, monitoring, and/or sampling, in the event the owner, assigns or heirs do not adequately maintain or monitor the facility. The owner, assigns or heirs shall reimburse the Township for all costs associated with said maintenance. The aformentioned rights granted the Township in no way diminish the responsibility of the owner, assigns or heirs of said maintenance and monitoring, and no liability will be assumed by the Township associated with required access for maintenance or monitoring purposes."
6) 
Identification of short-term and long-term ownership, operation, and maintenance responsibilities as well as schedules and costs for inspection and maintenance activities for each permanent stormwater or drainage BMP, including provisions for permanent access or maintenance easements.
7) 
If a development consists of structures or lots that are to be separately owned and in which streets, sewers, and other public improvements are to be dedicated to the Township, stormwater control facilities/BMPs may also be dedicated to and maintained by the Township. The Township has full discretion to accept any such dedication.
8) 
If a development site is to be maintained in a single ownership or if sewers and other public improvements are to be privately owned and maintained, then the ownership and maintenance of stormwater control facilities/BMPs shall be the responsibility of the owner or private management entity.
9) 
Facilities, areas, or structures used as stormwater BMPs shall be enumerated as permanent real estate appurtenances and recorded as deed restrictions or easements that run with the land.
10) 
The SWM site plan and report shall be recorded as a restrictive deed covenant that runs with the land.
11) 
The Township may take enforcement actions against an applicant for failure to satisfy any provision of this Part.
12) 
The Township, upon recommendation of the Township Engineer, shall make the final determination on the continuing maintenance responsibilities prior to final approval of the SWM site plan and report. The Township may require a dedication of such facilities as part of the requirements for approval of the SWM site plan. Such a requirement is not an indication that the Township will accept the facilities. The Township reserves the right to accept or reject the ownership and operating responsibility for any portion of the stormwater management controls.
13) 
The Township's acceptance of any dedicated stormwater BMP may be conditioned upon the payment of a fee to cover future costs of inspection, operation, maintenance and replacement, said fee to be calculated by the Township Engineer.
14) 
It shall be unlawful to alter or remove any permanent stormwater BMP required by an approved SWM site plan or to allow the property to remain in a condition that does not conform to an approved SWM site plan, unless the Township grants an exception in writing.
15) 
Prior to final approval of the SWM site plan and report, the applicant shall sign an operation and maintenance (O&M) agreement in form and substance approved by the Township Solicitor and the Board of Supervisors.
16) 
No person shall modify, remove, fill, landscape, or alter any existing stormwater BMP, facilities, areas, or structures, unless it is part of an approved maintenance program, without the written approval of the Township.
17) 
No person shall place any structure, fill, landscaping, or vegetation into a stormwater BMP, facilities, areas, structures, or within a drainage easement which would limit or alter the functioning of the BMP without the written approval of the Township.
(3) 
A copy of the proposed erosion and sedimentation control narrative and plans shall be submitted. The narrative and accompanying plans shall also be submitted to the Butler County Conservation District for review and approval.
(4) 
Stormwater Controls. All proposed stormwater runoff control measures must be shown on the development site plans, including methods for collecting, conveying and storing stormwater runoff on-site. The preliminary plan should provide information on the general type, location, sizing, etc., of all proposed facilities and their relationship to the existing watershed drainage system.
(a) 
The development site plan shall show the present contours of the land and the proposed contours of the land after completion of the proposed grading at one-foot intervals where slopes are less than 5%, two-foot intervals where the average slope is between 5% and 15% and at five-foot intervals where the average slope exceeds 15%.
(5) 
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. Drainage easements shall be delineated and recorded for all permanent facilities, swales and storm sewers to identify their owner, purpose, permanency and provide maintenance access. Any areas subject to special deed restrictions relative to or affecting stormwater management on the development site shall be shown. Easements shall prohibit excavation, the placement of fill, vegetation, or structures, and any alteration that may adversely affect the flow of stormwater or the function of a stormwater BMP in the easement.
(a) 
Easements are required for all areas used for off-site stormwater control.
(b) 
Where possible, easements shall be centered on side and/or rear lot lines.
(c) 
Nothing shall be planted or placed within the easement that would adversely affect the function of the easement or conflict with any conditions associated with such easement.
(d) 
All easements shown on the plan shall identify the owner, purpose or use. Example: "Private drainage easement to homeowners' association for ownership and maintenance."
(6) 
Permits/Approvals. A list of any approvals/permits relative to stormwater management that will be required from other governmental agencies (e.g., dam or encroachment permits from PADEP) and anticipated dates of submission/receipt should be included with the plan submission. Copies of applications may be requested by the Township. All stormwater or drainage-related computations or reports associated with these permit applications shall be submitted to the Township for reference and for review. Copies of all approved aforementioned permits and conditions shall be submitted to the Township upon receipt for reference purposes.
(7) 
One-Hundred-Year Floodplain Delineation.
(a) 
Stormwater management facilities located within or affecting the floodplain of any watercourse shall also be subject to the requirements of § 27-504, Floodplain Areas Overlay District, of the Zoning Ordinance [Chapter 27], as amended from time to time, which regulates construction and development within areas of the Township subject to flooding.
(b) 
The one-hundred-year floodplain must be delineated on all plans for all watercourses which have a watershed area of 150 acres or greater. Where, in the judgment of the Township, private property or public facilities may be adversely affected by the proposed activity, the one-hundred-year floodplain shall be established for any watercourse.
(c) 
The one-hundred-year floodplain shall be delineated by one of the following methods:
1) 
The Flood Insurance Study by the Federal Emergency Management Agency (FEMA).
2) 
A hydrologic report prepared by an individual registered in the Commonwealth of Pennsylvania to perform such duties. Calculations and channel hydraulic characteristics used to determine floodplain limits shall be provided.
(d) 
Minimum Basement Elevation. The minimum basement elevation of all structures adjacent to a stream, pond or stormwater management facility shall be a minimum of 1 1/2 feet above the one-hundred-year water surface elevation, measured at the upstream extent of the building. The regulating one-hundred-year water surface elevation associated with ponds or stormwater management facilities shall be the one-hundred-year elevation determined for emergency spillway calculations. All other provisions cited in § 27-504, Floodplains Areas Overlay District, of the Zoning Ordinance [Chapter 27] shall apply.
(8) 
Post-Construction Stormwater Management BMP Controls. Show any and all existing and proposed stormwater management or drainage controls and/or structures, such as storm sewers, swales, culverts, etc., that are located on the development site, or that are located off-site but will be affected by runoff from the development.
(9) 
Municipal Liability Disclaimer. Approval of a stormwater management plan by the Township shall not be construed as an indication that said plan complies with the requirements, laws, or standards of any agency of the commonwealth which may or may not govern said activity.
D. 
Design Criteria for Stormwater Detention Facilities. The following criteria shall be utilized for the design of proposed detention facilities:
(1) 
Detention facility(s) shall be designed such that the post-development peak runoff rates from the developed site are controlled at levels consistent with the allowable release rates determined for the one-, two-, ten-, twenty-five-, fifty-, and one-hundred-year design storms.
(2) 
All detention facilities shall be equipped with outlet structures to provide discharge control for the one-, two-, ten-, twenty-five-, fifty-, and one-hundred-year storm events. Provisions shall also be made for auxiliary structures (e.g., emergency spillways) that are capable of passing the unattenuated, post-development one-hundred-year storm peak flows, presuming blockage of all lower flow controls, without damaging the facilities. Open channel type emergency spillways shall be designed at an elevation above the design one-hundred-year water surface elevation for the facility.
(3) 
Shared storage facilities, which provide stormwater detention for more than one development site, will be encouraged. Such facilities shall meet the design criteria contained in this Part. Runoff from the development sites involved shall be conveyed to the facility in a manner so as to avoid adverse impacts, such as flooding or erosion, to channels and properties located between the development site and the shared storage facilities.
(4) 
Where detention facilities are used, the design of multiple-use facilities, such as ballfields or similar recreational uses, are encouraged wherever feasible. In addition to stormwater management, facilities should, where appropriate, allow for recreational uses including play areas, picnic grounds, etc. Consultation with the Township and prior approval are required before design. Provision for permanent wet ponds with stormwater management capabilities may also be appropriate.
(a) 
Multiple use basins should be constructed so that potentially dangerous conditions are not created.
(b) 
Water quality basins or recharge basins that are designed for a slow release of water or other extended detention ponds are not permitted for recreational uses, unless the ponded areas are clearly separated and secure.
(5) 
As a general rule, detention facilities will be designed as dry basins, although wet facilities will be considered in specific situations where they can be shown to represent a significant amenity or environmental benefit to the development and/or the Township. Facilities should be designed to induce water depths as shallow as possible.
(6) 
Except in approved wet basins, stormwater detention basins will be designed to drain completely. A low-flow channel with a minimum slope of 1% shall be installed to facilitate the conveyance of storm sewer flows to the basin outlet during frequent storm events. All interior portions of the basin will slope toward the outlet or low flow channel at a minimum slope of 2% (SS-19). Except in approved wet basins, all impoundment areas shall be adequately underdrained to prevent long-term ponding of water.
(7) 
Detention facility outfall pipes shall have a minimum of two antiseepage collars installed along the profile of the pipe. Antiseepage collars shall be constructed of reinforced concrete. Pipe bedding material shall be specified to prohibit seepage along the pipe trench and shall be in accordance with pipe manufacturer specifications (SS-20).
(8) 
All detention facilities designed with an earthen dam shall provide a minimum of one foot of freeboard between the peak emergency spillway design flow elevation [§ 17-350.7D(2)] and the top of the embankment.
(9) 
Emergency spillways not excavated in existing ground shall be designed with a suitable erosion protection lining approved by the Township. Riprap spillways shall provide a concrete cutoff wall at the spillway design crest elevation or grass-lined emergency spillway from a detention pond (Drawings SS-21A and SS-21B).
(10) 
All embankments will be designed according to sound engineering practice for such structures and must meet the approval of the Township. Facilities with a design water depth in excess of 10 feet may require a supporting report from a geotechnical engineer and shall be constructed under the supervision of the geotechnical engineer. In general, impoundment areas shall be designed to be contained within areas excavated within existing ground, rather than fill, whenever possible. Impoundment areas designed within fill shall require a supporting report from a geotechnical engineer addressing potential infiltration concerns and recommended solutions.
(11) 
A minimum embankment crest width of 10 feet shall be constructed for all earthen fill embankments. The outside slopes of the embankment shall not exceed two horizontal to one vertical. The interior slopes of the facility within the pool area shall not exceed a slope of three horizontal to one vertical. Design of facilities with flatter slopes for aesthetics and as a maintenance consideration are encouraged (SS-16).
(12) 
Except where special erosion protection measures are provided, all disturbed areas will be graded evenly, topped with four inches of topsoil, fertilized, seeded, and mulched by methods consistent with PennDOT Publication 408. PennDOT Formula C or equivalent seed mixtures containing crown vetch shall not be applied to the fill embankments of stormwater management facilities. The placement of trees within these areas shall also be prohibited.
(13) 
All outfalls to and from the facility shall be provided with endwalls and erosion control measures as per § 17-350.8C. Where land use and topography are suitable, detention facility outfalls to existing or constructed wetland areas will be encouraged to promote the water quality benefits of such areas.
(a) 
No outlet structure from a stormwater management facility or swale shall discharge directly onto a Township or state roadway without approval from the Township or PennDOT.
(14) 
Outlet control structures shall be constructed of reinforced concrete (cast-in-place or precast) and shall be recessed into the embankment (SS-17). Trash racks for low-flow control openings should be designed to provided four to 10 times the area of the low-flow opening and to facilitate debris removal and maintenance (SS-18).
(15) 
Access to all detention facilities shall be provided to the Township for maintenance purposes. This access shall be via a minimum ten-foot-wide gravel access road (SS-23) at a maximum grade of 15% as necessary to access the facility location, and by a written statement on recorded plans from the owner/operator of the facility granting access to the Township as noted in § 17-350.7C(2)(g)5) (SS-23).
(16) 
Detention facilities that are designed as sedimentation facilities during construction operations shall be desilted and regraded to original design dimensions and have all temporary sedimentation control devices removed prior to their conversion to detention facilities. Low-flow channels and underdrains should be installed with the conversion of the facility.
(17) 
In subdivisions or projects that are constructed in phases with individual detention facilities employed as sedimentation basins, said facilities shall be converted to their ultimate use as stormwater management facilities as soon as their tributary areas are stabilized per Butler County Conservation District standards. This conversion may be requested by the Township, with supportive corroboration from the Butler County Conservation District, and shall be implemented as outlined in § 17-350.7D(16), and the approved erosion and sedimentation control plan.
(18) 
An as-built drawing shall be required for each stormwater detention facility and BMP constructed. The drawing shall represent certification of the volume of the facility and the depth versus storage relationship, as well as the elevational relationships and dimensions of flow controls, including emergency spillways as appropriate. These relationships shall be shown on the drawing in table form or in report form. In the event that these relationships vary from the computations provided in the approved plan, revised storm routings may be required at the discretion of the Township. Modifications to the stormwater management facilities may be required by the Township based on the results of these routings. Final submission of as-built drawings shall be in accordance with § 17-350.3, and Appendix 17-B.[5]
[5]
Editor's Note: Appendix 17-B is included at the end of this chapter.
(19) 
Inlets structures shall be recessed into the embankment except when an alternative design is approved by the Township.
(20) 
In addition to the requirements of the Code, underground detention facilities shall meet the following minimum design standards:
(a) 
Underground tank facilities shall utilize the largest practical pipe diameter in order to provide ease of access for maintenance and inspection.
(b) 
Design measures to prevent pipe floatation and allow for visual inspection capabilities, adequate pipe ventilation and access for maintenance shall be provided.
(c) 
Underground chambers or pipes shall be aligned parallel to the contours.
(d) 
A minimum of two separate accessways to the underground detention facilities shall be provided for maintenance personnel.
(e) 
The underground detention facilities shall be designed to include overflow controls that either divert runoff via a flow splitter placed at the facility entrance or an overflow weir/orifice system designed in conjunction with the outlet of the facility.
(f) 
Maximum life expectancy of the underground system shall also be a design consideration for pipe material specifications.
(21) 
Wet Basins. Existing ponds or permanent pool basins may be used provided they meet the following requirements:
(a) 
A report, prepared by a biologist, ecologist, or similarly qualified professional, shall be submitted to the Township for review that evaluates the design of the proposed wet basin's ability to meet the following criteria:
1) 
The minimum permanent pool level to be maintained shall provide sufficient depth throughout the year to reduce the growth of unwanted vegetation and mosquitoes.
2) 
The pond is of sufficient size to allow the appropriate aquatic community needed to maintain a healthy pond ecology.
3) 
The design of a wet basin shall include the determination of the proposed site's ability to support a viable permanent pool. The design should take into account such factors as the required rate and quality of dry weather inflow, the quality of stormwater inflow, seasonal and longer-term variations in groundwater table, and effects of suspected pollutant loadings.
a) 
The wet basin shall be aerated with a fountain or stream bubbler to provide significant water movement to minimize algae accumulation and to maintain a healthy pond ecology.
b) 
An outlet structure shall be designed to allow complete drainage of the pond for maintenance.
(22) 
In addition to other requirements of the Code, naturalized basins shall meet the following requirements:
(a) 
The interior slopes of the basin within the pool area shall not exceed a slope of four horizontal to one vertical.
(b) 
The perimeter of stormwater detention basins shall be curvilinear so that from most edges of the basin the whole basin will not be in view. The Township may permit a more traditionally shaped (oval or rectangular) basin when conditions such as topography, parcel size, or other site conditions warrant. When permitted, the basin shall be designed in consultation with the Township to include a landscaped island or peninsula large enough and appropriately placed to reduce the perceived size of the basin.
(c) 
All areas of the naturalized basin, including basin floors, side slopes, berms, impoundment structures, or other earth structures, shall be planted with suitable vegetation such as naturalized meadow plantings or lawn grass specifically suited for stormwater basins. The plantings shall provide a satisfactory continuous cover to all areas of the basin and shall not interfere in the safe and efficient function of the basin as determined by the Township.
(23) 
Geological Assessment.
(a) 
Soils investigation report, including boring logs, compaction requirements, and recommendations for construction of detention basins.
(24) 
Stormwater management facility bottom (or surface of permanent pool) elevations must be greater than adjacent floodplain elevations (FEMA or HEC-RAS analysis). If no floodplain is defined, bottom elevations must be greater than existing ground elevations 50 feet from top of stream bank in the facilities' vicinity.
(25) 
Basin outflow culverts discharging into floodplains must account for tailwater. Tailwater corresponding to the one-hundred-year floodplain elevation must be used for all design storms, or the applicant may elect to determine flood elevations of the adjacent watercourse for each design storm. The floodplain is assumed to be 50 feet from top of stream bank in areas where a floodway is not designated or no other evidence is provided.
(26) 
The invert of all stormwater management facilities and underground infiltration/storage facilities shall be located a minimum of two feet above the seasonal high groundwater table. The invert of stormwater facilities may be lowered if adequate subsurface drainage is provided. Flows from underdrains need not be accounted for in volume or rate control calculations.
(27) 
Whenever possible, the side slopes and basin shape shall be amenable to the natural topography. Vertical side slopes and rectangular basins shall be avoided whenever possible.
(28) 
Landscaping and planting specifications must be provided for all stormwater management basins and be specific for each type of basin.
(a) 
Minimal-maintenance, saturation-tolerant vegetation must be provided in basins designed as water quality/infiltration BMPs.
(29) 
Berms shall be constructed using soils that conform to the unified soil classification of CH, MH, CL or ML. Soils used shall be tested to determine its density analysis per ASTM 698. The embankments will be constructed in a maximum of six-inch lifts. The lifts will each be compacted to a density at least 98% of its maximum dry density. Each layer of compacted fill shall be tested to determine its density per ASTM 2922 or ASTM 3017. One test per 50 cubic yards of material placed (at least one per layer) shall be performed by an independent testing agency.
(30) 
A cutoff and key trench of impervious material shall be provided under all embankments four feet or greater in height. The cutoff trench shall run the entire length of the embankment and tie into undisturbed natural ground.
(31) 
Compaction test reports shall be kept on file at the site and be subject to review at all times with copies being forwarded to the Township Engineer upon request.
(32) 
Temporary and permanent grasses or stabilization measures shall be established on the sides and base of all earthen basins within 15 days of construction.
E. 
Design Criteria for Collection/Conveyance Facilities.
(1) 
As a general rule, no stormwater may be discharged to unprotected areas such as hillsides or fills. Stormwater shall either be conveyed to the nearest established stream channel, as approved by the Township, or provided with an approved energy dissipation device. Conveyance shall be by pipe or erosion protected ditch.
(2) 
The design for culverts, pipes, and other stormwater conveyance structures shall be consistent with the design of the other stormwater management facilities. In the event that these structures are to be permitted by PADEP or PennDOT, the design criteria required by the state agency shall be utilized.
(3) 
All sites shall be graded to provide drainage away from and around structures, including on adjacent properties, to prevent potential flooding damage.
(4) 
Collection/conveyance facilities should not be installed parallel and close to the top or bottom of major embankments to avoid the possibility of embankment failure, with the exception of those facilities specifically designed to prohibit stormwater runoff from eroding slopes or preventing runoff from damaging downstream properties.
(5) 
Stormwater shall be collected and conveyed from upslope areas in a manner designed to prevent damage to downslope property(s) consistent with appropriate engineering standards. This system shall be identified by permanent easements, with the party responsible for ownership and maintenance identified.
(6) 
The design of storm sewer systems shall include evaluation of inlet grate capacities, bypass flows, entrance losses, storm pipe capacities, hydraulic grade line computations and outfall velocities, as appropriate. The storm sewer system shall function as intended under all these conditions for the required design storm as specified in § 17-350.7B(2)(b).
(7) 
Private stormwater may be connected to the public system pursuant to Detail SS-15.
(8) 
The stormwater management site plan shall included horizontal alignment, vertical profiles, and cross sections of all open channels, pipes, swales and other BMPs.
(9) 
Stormwater drainage systems shall be provided in order to permit unimpeded flow along natural watercourses, except as modified by stormwater management facilities or open channels consistent with this Part.
(10) 
When it can be shown that, due to topographic conditions, natural drainageways on the site cannot adequately provide for drainage, open channels may be constructed conforming substantially to the line and grade of such natural drainageways. Work within natural drainageways shall be subject to approval by PADEP under regulations at 25 Pa. Code Chapter 105 through the joint permit application process, or where deemed appropriate by PADEP, through the general permit process.
(11) 
The design of facilities over karst shall include an evaluation and implementation of measures to minimize adverse effects.
(12) 
In curbed roadway sections, the maximum encroachment of water on the roadway pavement shall not exceed half of a through travel lane or one inch less than the depth of curb during the ten-year design storm of five-minute duration. Gutter depth shall be verified by inlet capture/capacity calculations that account for road slope and opening area.
(13) 
Horizontal alignment, vertical profiles and cross sections of all open channels, pipes, swale and other BMPs shall be provided.
[Added by Ord. 2014-440, 1/30/2014]
F. 
Disposal of Stormwater from Roof, Foundation and Driveway Drains.
(1) 
Individual lots that are required to provide for on-lot stormwater management facilities per the stormwater management plan shall be identified on the recorded plan(s) for the subdivision.
(2) 
No roof, driveway or foundation drain shall be discharged onto the right-of-way of any street or the pavement of any street. Roof drains shall discharge to infiltration areas or vegetative BMPs to the maximum extent practicable. When it is more advantageous to connect directly to street or storm sewers, then the Township shall permit it on a case-by-case as per Subsections 6 and 6A. All residential dwellings not connected to a private or public stormwater collection and management system shall install a stormwater containment and disposal system at the direction of the Township in accordance with (SS-13). This system must be equipped with BMPs to address runoff quality if the development plan is not designed with a regional stormwater management facility containing BMPs. BMP measures shall be privately owned and maintained and must be implemented on the system on private property. Other acceptable methods of disposal include underground tanks, infiltration devices, storm sewers, water gardens, rain barrels, and grassed or other ground surfaces provided that adequate consideration is given to erosion protection, or any other method approved by the Township.
(3) 
At no time will any roof, driveway or foundation drains be allowed to be connected to the sanitary sewer line.
(4) 
The use of splash blocks is permitted. The location of the splash block discharge must be a minimum of five feet from foundations and 10 feet from the property line. Exceptions to this method may be permitted in the instance of townhouses or similar structures where common property lines exist. No stormwater runoff may be directed in such a manner as to disturb or damage neighboring properties.
(5) 
Houses located on the low side of the road can discharge drains (minimum of four-inch diameter) to the rear of the lot to a point of discharge onto a rock apron (size and dimensions to be specified) not less than 10 feet from the adjacent neighboring property line when the adjacent property has no development potential or there is a body of water between the properties and, provided that said discharge has been accounted for within the approved stormwater management plan and the discharge does not impact downstream property owners.
(6) 
Lots shall be graded in such a manner as to divert stormwater runoff away from adjacent property and structures consistent with appropriate engineering standards.
(7) 
French drain systems and rainwater collection systems shall be kept completely separate in all instances.
8. 
Standard Design Criteria.
A. 
Storm Sewer Trench SS-01 Within ROW. All storm sewer pipe within the right-of-way shall be installed in accordance with the standard in SS-01, Typical Storm Trench Detail, where located under all proposed pavements. Impervious area shall be installed in accordance with the standard in SS-01A.
B. 
Cradles and Reinforcements for Sewers. All cradles and reinforcements for sewers shall be approved by the Engineer.
C. 
Headwall/Endwall (SS-02). Concrete headwalls and splash aprons shall be constructed in accordance with the construction standard in SS-02, Standard Type D-W Endwall Detail, at the outfall of all storm sewers. Where watercourses are piped and filled, concrete headwall and splash aprons shall be constructed at both ends of the pipe. Riprap shall be placed at endwalls in accordance with SS-02 as appropriate. Preformed end-sections are an acceptable alternative with Township approval.
D. 
Concrete Encasement and Anchors for Sewers. All concrete encasement and anchors for sewers shall be approved by the Engineer. All storm sewers laid at slopes of 20% or greater shall have concrete anchors installed in accordance with SS-14.
E. 
Connection for Drop Manholes. All connections for drop manholes shall be approved by the Engineer.
F. 
Storm Sewer Outfall Channels and Drainage Swales. Permissible velocities of various channel linings [vegetation, rock lined, riprap, gabions (SS-04), etc.] shall be in accordance with the most recent version of the Erosion and Sediment Pollution Control Program Manual published by the Pennsylvania Department of Environmental Protection. Storm sewer outfall channels shall be trapezoidal or triangular shape with side slopes not to exceed two horizontal one vertical (ratio). Storm sewer outfall channels shall be designed in accordance with Chapter 13 of the Pennsylvania Department of Transportation Design Manual Part 2, Publication 13, § 13.3, titled "Watercourse Erosion Protection." Where drainage swales or open channels are used, they shall be suitably designed for ease of maintenance.
(1) 
Energy dissipators and/or level spreaders shall be installed at points where pipes or drainageways discharge to or from basins. Discharges to drainage swales shall be dissipated or piped to an acceptable point.
G. 
Springs. Any springs encountered during construction shall be piped and connected to the storm sewer system or extended to a natural watercourse as may be approved by the Engineer.
H. 
Riprap. All riprap used for outlet protection, bank stabilization or other means of protection shall be designed and installed in accordance with specifications outlined in PennDOT Publications 408 and 72.
I. 
Erosion and Sedimentation Control. Erosion and sedimentation control measures shall be designed and used during construction as per the approved plan from the Butler County Conservation District [Subsection 7C(1)(b)] and in accordance with details presented in the most recent version of the Erosion and Sediment Pollution Control Program Manual, Chapter 102, published by the Pennsylvania Department of Environmental Protection [25 Pa. Code, Chapter 102]. The following measures shall also be required by the Township in conjunction with the aforementioned plan:
(1) 
Individual On-Lot Controls. Individual on-lot controls shall be used for all residential lot development (SS-24).
(2) 
Rock Construction Entrance. All individual residential lot development shall employ a rock construction entrance for vehicular access to the lot from paved roadways. The construction entrance shall be installed in accordance with details provided in the most recent version of the PADEP Erosion and Sediment Pollution Control Program Manual.
(3) 
Slope Stabilization. All cut or fill slopes that exceed 10 feet in vertical height and a 3:1 (h:v) slope shall be stabilized with an erosion control blanket to prevent slope erosion and promote seed growth in accordance with the most recent version of the PADEP Erosion and Sediment Pollution Control Program Manual requirements. A detail shall be included with the plans specifying the type of blanket and installation procedures. Slopes shall be redressed with topsoil prior to final stabilization to promote optimum growth of vegetation.
(4) 
Energy Dissipators. All energy dissipators, such as riprap aprons, plunge basins, etc., shall be designed based on outlet velocities associated with the design storm for the subject outfall pipe.
(5) 
Construction of temporary roadways (e.g., for utility construction, timber harvesting, etc.) shall comply with all applicable standards for erosion and sedimentation control and stream crossing regulations under 25 Pa. Code, Chapters 102 and 105. The Erosion and Sedimentation Control Plan shall be submitted to the Butler County Conservation District for approval and shall address the following, as applicable:
(a) 
Design of the roadway system, including haul roads, skid roads, landing areas, trails, and storage and staging areas.
(b) 
Runoff control structures (e.g., diversions, culverts, detention ponds, etc.).
(c) 
Stream crossings for both perennial and intermittent streams.
(d) 
Access to public roadways, including design of rock construction entrance for mud and debris control.
(e) 
A remediation plan for restoring the disturbed area through regrading, topsoil placement, reseeding, and other stabilization techniques, as required.
(6) 
The location of all erosion and sedimentation control facilities, shown on a plan separate from the SWM site plan (typically an E&S Plan).
(7) 
Construction sequence.
(8) 
Identification of short-term and long-term ownership, operations, and maintenance responsibilities.
(9) 
Notes and Statements:
(a) 
A statement signed by the landowner acknowledging that the stormwater BMPs are fixtures that cannot be altered or removed without prior approval by the Township.
(b) 
A statement referencing the operation and maintenance (O&M) agreement and stating that the O&M agreement is part of the SWM site plan.
(c) 
A note indicating that record drawings will be provided for all stormwater facilities prior to occupancy or the release of the surety bond.
(d) 
The following signature block for the qualified professional preparing the stormwater management plan:
"I,__________, hereby certify that the Stormwater Management Plan meets all design standards and criteria of the Cranberry Township Stormwater Management Ordinance."
(e) 
The following signature block for the Township Engineer or approved Township representative reviewing the Stormwater Management Plan:
"I,__________, have reviewed this Stormwater Management Plan in accordance with the Design Standards and Criteria of the Cranberry Township Stormwater Management Ordinance."
J. 
Prohibition Against Non-Stormwater Discharges. No person shall allow or cause to allow discharges or deposition of foreign material into the Township's separate storm sewer system or stormwater management systems which are not composed entirely of stormwater, except discharges allowed under a state or federal permit or as set forth below:
(1) 
Prohibited Connections. The following connections to a Township separate storm sewer system are prohibited:
(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.
(b) 
Any drain or conveyance connected from a nonresidential land use to the Township's separate storm sewer system that has not been documented in plans, maps, or equivalent records, and approved by the Township.
(2) 
Discharges that 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:
(a) 
Discharges from firefighting activities.
(b) 
Uncontaminated water from foundation or from footing drains.
(c) 
Potable water sources, including dechlorinated water line and fire hydrant flushings.
(d) 
Flows from riparian habitats and wetlands.
(e) 
Lawn watering.
(f) 
Irrigation drainage.
(g) 
Springs.
(h) 
Pavement wash waters 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.
(i) 
Routine external building washdown (which does not use detergents or other compounds).
(j) 
Air-conditioning condensate.
(k) 
Water from individual residential car washing.
(l) 
Dechlorinated swimming pool discharges.
(m) 
Uncontaminated groundwater.
(n) 
Water from crawl space pumps.
(3) 
In the event that the Township subsequently determines that any of the discharges identified within Subsection J(2) significantly contribute to pollution of waters of the commonwealth, or if so notified by DEP, then the Township will immediately notify the responsible person to cease the discharge or provide testing data that shows the discharge in question does not degrade the receiving stream characteristics as listed in 25 Pa. Code, Chapter 93.
(4) 
Upon notice provided by the Township under Subsection J(3), 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.
(5) 
Nothing in this section shall affect a discharger's responsibilities under state law.
K. 
Suggested Post-Construction Stormwater BMPs.
(1) 
Innovative stormwater BMPs and recharge facilities are encouraged (e.g., rooftop storage, drywells, cisterns, recreation area ponding, diversion structures, porous pavements, holding tanks, infiltration systems, in-line storage in storm sewers, and grading patterns). They shall be located, designed, and constructed in accordance with the latest technical guidance published by PADEP, provided that they are accompanied by detailed engineering plans and performance capabilities and supporting site specific soils, geology, runoff and groundwater and infiltration rate data to verify proposed designs. Additional guidance from other sources may be accepted at the discretion of the Township Engineer (a preapplication meeting is suggested).
(a) 
The following is a listing of detention and control methods that may be used in stormwater management systems, if appropriate. The choice of control techniques is not limited to those appearing on this list.
1) 
Detention/retention basins.
2) 
Roof-top storage.
3) 
Parking lot and street storage.
4) 
Seepage pits, seepage trenches, level spreaders or other infiltration structures.
5) 
Bioretention areas.
6) 
Porous payement and concrete lattice block surfaces.
7) 
Grassed channels and vegetated strips.
8) 
Routed flow over grass.
9) 
Decreased impervious area coverage.
10) 
Water quality storage volume in detention facilities.
(b) 
The use of other control methods which meet the criteria in this section shall be permitted when approved by the Township Engineer. Various combinations of methods should be designed to suit the particular requirements of the type of development and the topographic features of the project area. Additional erosion and sedimentation control design standards and criteria that must be applied where infiltration BMPs are proposed include the following:
1) 
Areas proposed for infiltration BMPs shall be protected from sedimentation and compaction during the construction phase so as to maintain their maximum infiltration capacity.
2) 
Infiltration BMPs shall be protected from receiving sediment-laden runoff.
3) 
The source of protection for infiltration BMPs shall be identified (i.e., orange construction fence surrounding the perimeter of the BMP).
(2) 
Infiltration. Prevention of stormwater runoff is the key objective of 25 Pa. Code, Chapter 93, of the PADEP regulations since runoff can change the physical, chemical, and biological integrity of waterbodies thereby impacting water quality. All stormwater management plans shall describe how these water quality protection requirements will be met.
(a) 
Infiltration BMPs shall be evaluated and utilized to the maximum extent possible to manage the net change in stormwater runoff generated so that post-construction discharges do not degrade the physical, chemical, and biological characteristics of the receiving waters. These BMPs may be used to satisfy all or part of the requirements in this subsection.
1) 
Description of, justification, and actual field results for infiltration testing with respect to the type of test and test location for the design of infiltration BMPs.
(b) 
Post-construction stormwater infiltration of runoff shall replicate preconstruction infiltration of runoff to the maximum extent possible. In calculating the recharge volume of runoff that can be infiltrated at a site, the following methodology shall be used:
REv = [(S){0.05+0.009(I)}(A)]/12
Where
S
=
Soil specific recharge factor in inches (obtain from table below).
I
=
Impervious surface percentage.
A
=
Project area in acres.
REv, recharge volume, is computed in acre-feet
Hydrologic Soil Group (HSG)
S
A
0.38
B
0.25
C
0.13
D
0.06
If more than one HSG is present at a site, a composite recharge volume shall be computed based on the proportion of the total site area within each HSG.
(c) 
A detailed soils evaluation of the project site shall be performed to determine the suitability of infiltration BMPs. The evaluation shall be performed by a qualified professional and, at a minimum, address soil permeability, depth to bedrock, susceptibility to sinkhole formation, and subgrade stability. If infiltration is not a viable option on the subject site, the water quality storage option must be implemented as described in Subsection 8K(3).
(d) 
All infiltration BMPs shall be located a minimum of 10 feet away from the foundation wall of any structure.
(e) 
Any infiltration BMP shall be capable of infiltrating the impounded water within 48 hours.
1) 
Unless specifically designed as a volume control or water quality facility, all stormwater management facilities must empty over a period of time not less than 24 hours and not more than 72 hours from the end of the facility's inflow hydrograph. Infiltration tests performed at the facility locations and proposed basin bottom depths, in accordance with the BMP Manual, must support time-to-empty calculations if infiltration is a factor.
(f) 
The infiltration system shall have positive overflow controls to prevent storage within one foot of the finished surface or grade.
(g) 
Infiltration rates shall not be used in computing the storage volume of the detention/retention system for the development.
(h) 
Infiltration BMPs shall not be used in areas of known strip mining or in limestone areas.
(3) 
Water Quality Storage. In order to protect and maintain water quality, additional stormwater runoff created by proposed developments must be captured, stored, and treated. In addition, post-construction stormwater infiltration of runoff must replicate preconstruction infiltration of runoff to the maximum extent possible.
(a) 
The volume of additional stormwater runoff to be captured, stored, and treated is called the "water quality volume" (WQv). The formula for determining WQv is:
WQv = [(P){0.05+0.009(I)}(A)]/12
Where
P
=
Rainfall depth of 1-year storm = 1.13 inches.
I
=
Impervious surface percentage.
A
=
Drainage area in acres.
WQv is computed in acre-feet.
(b) 
This volume is to be released over a twenty-four-hour extended detention period. This calculation is to be performed as a separate detention facility routing in the submitted stormwater management report.
(c) 
Meet the water quality goals of this Part by implementing measures to:
1) 
Minimize disturbance to floodplains, wetlands, natural slopes, existing native vegetation and woodlands.
2) 
Create, maintain, or extend riparian buffers and protect existing forested buffers.
3) 
Provide trees and woodlands adjacent to impervious areas whenever feasible.
4) 
Minimize the creation of impervious surfaces and the degradation of waters of the commonwealth and promote groundwater recharge.
5) 
Protect natural systems and processes (drainageways, vegetation, soils, and sensitive areas) and maintain, as much as possible, the natural hydrologic regime.
6) 
Incorporate natural site elements (wetlands, stream corridors, mature forests) as design elements.
7) 
Avoid erosive flow conditions in natural flow pathways.
8) 
Minimize soil disturbance and soil compaction.
9) 
Minimize thermal impacts to waters of the commonwealth.
10) 
Disconnect impervious surfaces by directing runoff to pervious areas wherever possible and decentralize and manage stormwater at its source.
(4) 
Alteration of BMPs. No person shall modify, remove, fill, landscape, or alter any existing stormwater BMP, including stormwater channels, unless part of an approved maintenance program, without the written approval of the Township.
L. 
Best Management Practices (BMPs). The use of practical structural and nonstructural BMPs will be encouraged by the Township in the design of site drainage systems and land development. Design of such measures shall consider the limitations of the site topography and soils, as well as identify the benefits of proposed measures and maintenance requirements. Technical requirements and limitations of BMPs are provided in the Pennsylvania Handbook of Best Management Practices for Developing Areas. The standard set forth in the most current version of this document shall be considered the construction standards of this Part.
M. 
Sensitive Areas and Stormwater Hotspots.
(1) 
Sensitive Areas and Stormwater Hotspots: Sensitive areas and water quality sensitive developments as defined below which require special consideration with regard to stormwater management.
(a) 
"Sensitive areas" are defined as those areas that, if developed, have the potential to endanger a water supply. These areas consist of the delineated one-year zone of contribution and direct upslope areas tributary to the water supply wells. Municipalities may update the sensitive area boundaries based on new research or studies as required.
(b) 
"Stormwater hotspots" are defined as a land development project that has a high potential to endanger local water quality, and could potentially threaten groundwater reservoirs. The Township Engineer will determine what constitutes these classifications on a case-by-case basis. The PADEP wellhead protection contaminant source list shall be used as a guide in these determinations. Industrial manufacturing site and hazardous material storage areas must provide NPDES SIC codes.
(2) 
Performance Standards.
(a) 
The location of the boundaries of sensitive areas is set by drainage areas tributary to any public water supply. The exact location of these boundaries as they apply to a given development site shall be determined using mapping at a scale that accurately defines the limits of the sensitive area. If the project site is within the sensitive area (in whole or in part), two-foot contour interval mapping shall be provided to define the limits of the sensitive area. If the project site is adjacent to but within 500 linear feet of a defined sensitive area, a five-foot contour interval map defining the limits of the sensitive area shall be included in the stormwater management plan to document the site's location relative to the sensitive area.
(b) 
Stormwater hotspots may be required to prepare and implement a stormwater pollution prevention plan and file notice of intent as required under the provision of the EPA Industrial Stormwater NPDES Permit Requirements.
(c) 
Stormwater hotspots must use an acceptable pretreatment BMP prior to volume control and/or rate control BMPs. Acceptable pretreatment BMPs for these developments include those based on filtering, settling, or chemical reaction processes such as coagulation.
N. 
Protected Watershed Requirements.
(1) 
For any regulated activity within a protected watershed (High Quality or Exceptional Value), the applicant shall meet requirements as contained in 25 Pa. Code, Chapter 93, as required and applicable.
(2) 
An existing resources and site analysis plan shall be prepared to provide the developer and the Township with a comprehensive analysis of existing conditions, both on the proposed development site and within 500 feet of the site. Conditions beyond the parcel boundaries may be described on the basis of existing published data available from governmental agencies and from aerial photographs. The Township shall review the plan to assess its accuracy, conformance with Township ordinances, and likely impact upon the natural and cultural resources on the property. The following information shall be required:
(a) 
Complete current perimeter boundary survey of the property to be subdivided or developed prepared by a registered surveyor, showing all courses, distances, and area and tie-ins to all adjacent intersections.
(b) 
A vertical aerial photograph enlarged to a scale not less detailed than one inch equals 400 feet, with the site boundaries clearly marked.
(c) 
Natural features, including:
1) 
Contour lines at intervals of not more than two feet. (Ten-foot intervals are permissible beyond the parcel boundaries, interpolated from USGS published maps.) Contour lines shall be based on information derived from a topographic survey for the property, evidence of which shall be submitted, including the date and source of the contours. Datum to which contour elevations refer and references to known, established benchmarks and elevations shall be included on the plan.
2) 
Steep slopes in the following ranges: 15% to 25%; 25% and greater. The location of these slopes shall be graphically depicted by category on the plan. Slope shall be measured over three or more two-foot contour intervals.
3) 
Areas within the floodway, flood fringe, and approximated floodplain.
4) 
Watercourses, either continuous or intermittent and named or unnamed, and lakes, ponds or other water features as depicted on the USGS Quadrangle Map, most current edition.
5) 
Wetlands and wetland margins.
6) 
Riparian buffers.
7) 
Soil types and their boundaries, as mapped by the USDA Natural Resource Conservation Service, including a table listing the soil characteristics pertaining to suitability for construction and, in unsewered areas, for septic suitability. Alluvial and hydric soils shall specifically be depicted on the plan.
8) 
Existing vegetation, denoted by type, including woodlands, hedgerows, tree masses, tree lines, individual freestanding trees over six inches DBH, wetland vegetation, pasture or croplands, orchards, permanent grass land, old fields, and any other notable vegetative features on the site. Vegetative types shall be described by plant community, relative age, and condition.
9) 
Any identified Pennsylvania Natural Diversity Inventory (PNDI) site conflicts.
10) 
Geologic formations on the tract, including rock outcroppings, cliffs, sinkholes, and fault lines, based on available published information or more detailed data obtained by the applicant.
(d) 
Existing man-made features, including:
1) 
Location, dimensions, and use of existing buildings and driveways.
2) 
Location, names, widths, center-line courses, paving widths, identification numbers, and rights-of-way of existing streets and alleys.
3) 
Location of trails that have been in public use (pedestrian, equestrian, bicycle, etc.).
4) 
Location and size of existing sanitary sewage facilities.
5) 
Location and size of drainage facilities.
6) 
Location of water supply facilities, including wellhead protection areas.
7) 
Any easements, deed restrictions, rights-of-way, or any other encumbrances upon the land, including location, size, and ownership.
8) 
Site features or conditions such as hazardous waste, dumps, underground tanks, active and abandoned wells, quarries, landfills, sandmounds, and artificial land conditions.
(e) 
Total acreage of the tract, the adjusted tract area, where applicable, and the constrained land area with detailed supporting calculations.
(3) 
Stormwater Management System Concept Plan. A written and graphic concept plan of the proposed post-development stormwater management system shall be prepared and include:
(a) 
Preliminary selection and location of proposed structural stormwater controls;
(b) 
Location of existing and proposed conveyance systems such as grass channels, swales, and storm drains;
(c) 
Location of floodplain/floodway limits;
(d) 
Relationship of site to upstream and downstream properties and drainages.
(e) 
Preliminary location of proposed stream channel modifications, such as bridge or culvert crossings.
(4) 
Consultation Meeting. Prior to any stormwater management permit application submission, the land owner or developer shall meet with the Township for a consultation meeting on a concept plan for the post-development stormwater management system to be utilized in the proposed project. This consultation meeting shall take place at the time of the preliminary plan or other early step in the development process. The purpose of this meeting is to discuss the post-development stormwater management measures necessary for the proposed project, as well as to discuss and assess constraints, opportunities and potential ideas for stormwater management designs before the formal site design engineering is commenced.
(5) 
All proposed regulated activities within a protected watershed shall utilize, to the maximum extent possible, low-impact development practices as contained in Appendix 17-B.[6]
(a) 
The SWM plan and report shall address the following:
1) 
Design using nonstructural BMPs:
a) 
Lot configuration and clustering.
i. 
Reduced individual lot impacts by concentrated/clustered uses and lots.
ii. 
Lots/development configured to avoid critical natural areas.
iii. 
Lots/development configured to take advantage of effective mitigative stormwater practices.
iv. 
Lots/development configured to fit natural topography.
b) 
Minimum disturbance.
i. 
Define disturbance zones (excavation/grading) for the site and individual lots to protect maximum total site area from disturbance.
ii. 
Barriers/flagging proposed to protect designated nondisturbance areas.
iii. 
Considered mitigative practices for minimal disturbance areas (e.g., soil restoration).
iv. 
Considered reforestation and revegetation opportunities.
c) 
Reduce impervious coverage.
i. 
Reduced road width.
ii. 
Reduced driveway lengths and widths.
iii. 
Reduced parking ratios and sizes.
iv. 
Utilized porous surfaces for applicable features.
d) 
Stormwater disconnected from impervious area.
i. 
Disconnected drives/walkways/small impervious areas to natural areas.
ii. 
Use rain barrels and/or cisterns for lot irrigation.
2) 
Apply structural BMP selection process that meets runoff quantity and quality needs.
a) 
Manage close to source with collection with conveyance minimized.
b) 
Consistent with site factors (e.g., soils, slope, available space, amount of sensitive areas, pollutant removal needs).
c) 
Minimize footprint and integrate into already disturbed areas/other building program components (e.g., recharge beneath parking areas, vegetated roofs).
d) 
Consider other benefits such as aesthetic, habitat, recreational and educational benefits.
e) 
BMPs selection based on maintenance needs that fit owner/users.
f) 
BMPs sustainable using a long-term maintenance plan.
[6]
Editor's Note: Appendix 17-B is included at the end of this chapter.
O. 
Riparian Buffer Requirements. Riparian buffers shall be provided for any regulated activity to meet the requirements of 25 Pa. Code, including Chapters 93, 96, and 102.
9. 
SWM Site Plan and Report Review.
A. 
The Township shall require receipt of a complete SWM site plan and report as specified in this Part. The Township shall review the SWM site plan and report for consistency with the purposes, requirements, and intent of this Part.
(1) 
SWM site plans shall be of one size and in a form that meets the requirements for recording in the Office of the Recorder of Deeds of Butler County.
(a) 
Plans for tracts of less than 20 acres shall be drawn at a scale of one inch equals no more than 50 feet;
(b) 
Plans for tracts of 20 acres or more, plans shall be drawn at a scale of one inch equals no more than 100 feet;
(c) 
Lettering shall be drawn to a size to be legible if the plans are reduced to 1/2 size.
B. 
The Township shall not approve any SWM site plan and report that is deficient in meeting the requirements of this Part. At its sole discretion and in accordance with this Part, when a SWM site plan and report is found to be deficient, the Township may disapprove the submission and require a resubmission, or in the case of minor deficiencies, the Township may accept submission of modifications.
C. 
The Township shall notify the applicant in writing within 45 calendar days whether the SWM site plan and report is approved or disapproved if the SWM site plan and report is not part of a subdivision or land development plan. If the SWM site plan and report involves a subdivision or land development plan, the timing shall follow the subdivision and land development process according to the Municipalities Planning Code.
D. 
The Township shall not issue a building permit for any regulated activity if the SWM site plan and report has been found to be inconsistent with this Part, as determined by the Township. All required permits from PADEP must be obtained prior to issuance of a building permit.
10. 
Modification of Plans.
A. 
A modification to a submitted SWM site plan and report for a development site that involves a change in stormwater management facilities or techniques, or that involves the relocation or redesign of stormwater management facilities, or that is necessary because soil or other conditions are not as stated on the SWM site plan as determined by the Township, shall require a resubmission of the modified SWM site plan in accordance with this Part.
11. 
Resubmission of Disapproved SWM Site Plan and Report.
A. 
A disapproved SWM site plan and report may be resubmitted with the revisions addressing the Township's concerns documented in writing, to the Township in accordance with this Part. The applicable Township review fee must accompany a resubmission of a disapproved SWM site plan and report.
12. 
Authorization to Construct and Term of Validity.
A. 
The Township's approval of a SWM site plan and report authorizes the regulated activities contained in the SWM site plan for a maximum term of validity of five years following the date of approval. The Township may specify a term of validity shorter than five years in the approval for any specific SWM site plan. Terms of validity shall commence on the date the Township signs the approval for a SWM site plan. If stormwater management facilities included in the approved SWM site plan have not been constructed, or if a record drawing of these facilities has not been approved within this time, then the Township may consider the SWM site plan disapproved and may revoke any and all permits or approvals.
13. 
Record Drawings, Completion Certificate and Final Inspection.
A. 
The applicant shall be responsible for providing record drawings of all stormwater BMPs included in the approved SWM site plan. The record drawing and an explanation of any discrepancies with the approved SWM site plan shall be submitted to the Township as a prerequisite for the release of the guarantee or issuance of an occupancy permit.
B. 
The record drawing shall include a certification of completion signed by a qualified professional verifying that all permanent stormwater BMPs have been constructed according to the approved SWM site plan and report.
(1) 
Drawings shall show all approved revisions and elevations and inverts to all manholes, inlets, pipes, and stormwater control facilities.
(2) 
Submission shall include a comparison of the constructed stage-storage (volume vs. elevation) of all aboveground and below ground stormwater storage facilities to the approved design.
C. 
After receipt of the record drawing and certification of completion by the Township, the Township may conduct a final inspection.
14. 
Financial Guarantee.
A. 
The applicant shall provide a financial guarantee to the Township for the timely installation and proper construction of all stormwater management controls as required by the approved SWM site plan and this Part, equal to 110% of the full construction cost of the required controls in accordance with the Municipalities Planning Code.
B. 
At the completion of the project and as a prerequisite for the release of the financial guarantee, the applicant shall:
(1) 
Provide a certification of completion from an engineer, architect, surveyor or other qualified person verifying that all permanent facilities have been constructed according to the SWM site plan and report and approved revisions thereto.
(2) 
Provide a set of record drawings.
(3) 
Request a final inspection from the Township to certify compliance with this Part after receipt of the certification of completion and record drawings by the Township.
15. 
Suspension and Revocation.
A. 
Any approval or permit issued by the Township may be suspended or revoked for:
(1) 
Noncompliance with or failure to implement any provision of the approved SWM site plan or operation and maintenance (O&M) agreement.
(2) 
A violation of any provision of this Part or any other applicable law, ordinance, rule or regulation relating to the regulated activity.
(3) 
The creation of any condition or the commission of any act during the regulated activity which constitutes or creates a hazard or nuisance, pollution, or which endangers the life or property of others.
B. 
A suspended approval or permit may be reinstated by the Township when:
(1) 
The Township or its designee has inspected and approved the corrections to the violation(s) that caused the suspension.
(2) 
The Township is satisfied that the violation(s) has been corrected.
C. 
An approval that has been revoked by the Township cannot be reinstated. The applicant may apply for a new approval under the provisions of this Part.
16. 
Waivers. All waivers must be applied for or submitted at the same time as an application for land development, subdivision, grading.
A. 
The provisions of this Part are the minimum standards for the protection of the public welfare.
B. 
All waiver requests must meet the provisions of Subsections E and G.
(1) 
Waivers shall not be issued from implementing such measures as necessary to:
(a) 
Meet state water quality standards and requirements.
(b) 
Protect health, safety, and property.
(c) 
Meet special requirements for High Quality (HQ) and Exceptional Value (EV) watersheds.
(2) 
Municipalities will then consider waivers in accordance with § 17-350.16D.
C. 
If an applicant for SWM plan and report approval demonstrates to the satisfaction of the Township that a mandatory provision of the Stormwater Management Ordinance is unreasonable or causes unique or undue hardship, or that an alternate design may result in a superior result in meeting the intent and purpose of the Stormwater Management Act and the Township ordinances, the Township may, at its sole discretion, grant a waiver to such provision if the requirements of this Section are met.
D. 
The applicant shall submit all requests for waivers in writing and shall include such requests as a part of the plan review and approval process. The applicant shall state in full the facts of unreasonableness or hardship on which the request is based, the provision or provisions of the ordinance that are involved, and the minimum waiver or relief that is necessary. The applicant shall state how the requested waiver and how the applicant's proposal shall result in an equal or better means of complying with the intent or purpose and general principles of this Part.
E. 
The Township may grant applications for waivers when the following findings are made, as relevant:
(1) 
That the waiver shall result in an equal or better means of complying with the intent of this Part.
(2) 
That the waiver is the minimum necessary to provide relief.
(3) 
That the applicant is not requesting a waiver based on cost considerations.
(4) 
That existing down gradient stormwater problems will not be exacerbated.
(5) 
That runoff is not being diverted to a different drainage area.
(6) 
That increased flooding or ponding on off-site properties or roadways will not occur.
(7) 
That potential icing conditions will not occur.
(8) 
That increase of peak flow or volume from the site will not occur.
(9) 
That erosive conditions due to increased peak flows or volume will not occur.
(10) 
That adverse impact to water quality will not result.
(11) 
That increased one-hundred-year floodplain levels will not result.
(12) 
That increased or unusual Township maintenance expenses will not result from the waiver.
(13) 
That the amount of stormwater generated has been minimized to the greatest extent allowed.
(14) 
That infiltration of runoff throughout the proposed site has been provided where practicable, and predevelopment groundwater recharge protected.
(15) 
That peak flow attenuation of runoff has been provided.
(16) 
That long-term operation and maintenance activities are established.
(17) 
That the receiving streams and/or water bodies will not be adversely impacted in flood-carrying capacity, aquatic habitat, channel stability and erosion and sedimentation.
F. 
The Township may charge a fee for each waiver request, which shall be used to offset the administrative costs of reviewing the waiver request. The applicant shall also agree to reimburse the Township for reasonable and necessary fees that may be incurred by the Township Engineer, Township Solicitor or other professional as the Township deems necessary in any review of a waiver request.
G. 
In granting waivers, the Township may impose reasonable conditions that will, in its judgment, secure substantially the objectives of the standards or requirements that are to be modified.