Source: https://www.ecode360.com/30829027
Timestamp: 2019-04-20 21:00:22
Document Index: 319110152

Matched Legal Cases: ['§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', 'art 2', '§ 1', '§ 1', 'art 2', '§ 2', '§ 1', 'art 2', 'art 2', '§ 3', '§ 1', 'art 2', '§ 4', '§ 1', '§ 5', '§ 1', '§ 26', 'art 2', '§ 6', '§ 7', '§ 8', '§ 1', '§ 26', '§ 26', 'art 2', '§ 1', '§ 9', '§ 1', '§ 2', '§ 680', '§ 691', '§ 3', '§ 851', '§ 2704', '§ 67704', '§ 10101', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 102', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 26', '§ 735', '§ 26', 'art 1', '§ 26']

Township of Frazer, PA Water
§ 26-101 Purpose and Short Title.
§ 26-104 Stormwater Management Requirements.
§ 26-105 Plan Requirements.
§ 26-106 Inspection.
§ 26-107 Fees.
§ 26-108 Financial Guarantees.
§ 26-109 Waiver Procedure.
§ 26-110 Enforcement and Penalties.
Ch 26 Pt 2 DEER CREEK WATERSHED
§ 26-203 Definitions.
§ 26-204 General Provisions.
§ 26-205 Stormwater Management Plan.
§ 26-206 Permanent Stormwater Management Design Standards.
§ 26-207 Operation and Maintenance Responsibilities.
§ 26-208 Plan Submission, Review and Review Fees.
Stormwater Management; Water
Ch 23, Ch 26 Pt 1
Attachment 1 Appendix 26-2-A Attachment 2 Appendix 26-2-B Attachment 3 Appendix 26-2-C Attachment 4 Appendix 26-2-D Attachment 5 Appendix 26-2-E Attachment 6 Deer Creek Watershed
Part 2 DEER CREEK WATERSHED
[Ord. 70, 5/4/1989, § 1; as amended by Ord. 153, 10/7/2008, § 1]
The purpose of this Part is to control stormwater throughout the Township, except as modified by any watershed regulations set forth in this chapter, including the Deer Creek Watershed Ordinance [Chapter 26, Part 2] in a manner consistent with good engineering practice and applicable Federal, State, County and Township laws, statutes, ordinances, resolutions and regulations. This Part shall be known and cited as the "Frazer Township Stormwater Management Ordinance."
[Ord. 70, 5/4/1989, § 2; as amended by Ord. 153, 10/7/2008, § 1]
Unless otherwise stated, the following words, terms and phrases shall have the meanings indicated in this section.
The removal of the surface of the land through the combined action of man's activities and natural processes at a rate greater than would occur because of the natural processes alone.
The Allegheny County Conservation District, which serves Allegheny County, or its successor.
The watershed area identified in Appendix 26-2-F of the Deer Creek Watershed Ordinance [Chapter 26, Part 2].
DEER CREEK WATERSHED ORDINANCE
Chapter 26, Part 2 of the Frazer Township Code of Ordinances, Deer Creek Watershed, as amended.
As defined by the Subdivision and Land Development Ordinance [Chapter 22].
A surface which prevents the penetration of water into the ground.
The flow of water overland and/or in water bodies that results from and occurs during and immediately following a rainfall event.
The approved detailed analysis, design and drawings of the stormwater management system required under this Part.
That individual authorized by the Board of Supervisors to be the administrator of the day-to-day application of the provisions contained in this Part.
[Ord. 70, 5/4/1989, § 3; as amended by Ord. 153, 10/7/2008, § 1]
General. The following activities are regulated under the provisions of this Chapter:
Stormwater activities in the Deer Creek Watershed are regulated under the Deer Creek Watershed Ordinance [Chapter 26, Part 2].
Compliance with Laws. The developer and the use and development of all property shall comply with all applicable Federal, State. County and Township laws, statutes, ordinances, resolutions and regulations, including, but not limited to, the Zoning Ordinance [Chapter 27], the Subdivision and Land Development Ordinance [Chapter 22] and this Part.
Permits and Approvals. The developer shall apply for and obtain any and all necessary Federal, State, County and Township permits and approvals for the use and development of property in the Township. The developer and use and development of any such property shall comply with all such Federal, State, County and Township permits and approvals.
[Ord. 70, 5/4/1989, § 4; as amended by Ord. 153, 10/7/2008, § 1]
The following requirements apply to all activities regulated by this Part:
Stormwater Runoff. The quantity, velocity and direction of stormwater runoff must be managed in a manner which protects health and property from possible injury. Stormwater drainage facilities shall be installed to insure that rates of runoff after development shall not be greater than the runoff which would occur on the site in its natural state. Any plan submitted under this Part must consider all runoff flowing over the property covered by the plan.
Erosion and Sedimentation. Measures to prevent accelerated erosion and resulting sedimentation must at a minimum meet the standards of the Conservation District. The provisions of the most recent edition of the Pennsylvania Department of Environmental Protection's "Stormwater Best Management Practices (BMP) Manual" should be used where applicable during earth disturbance activities and after such earth disturbance activities are completed.
Toxic Materials. No discharge of toxic materials into any stormwater management system shall be permitted.
[Ord. 70, 5/4/1989, § 5; as amended by Ord. 137, 7/5/2005; and by Ord. 153, 10/7/2008, § 1]
Prior to the commencement of any activity regulated by this Part, the owner, subdivider, developer, his agent, or other responsible party must have a stormwater management plan reviewed by the Township Engineer and approved by the Board of Supervisors. Stormwater management plans submitted as part of a subdivision and/or land development plan application under the Township Subdivision and Land Development Ordinance [Chapter 22] shall be reviewed and approved by the Board of Supervisors as part of the subdivision and/or land development plan application.
The following activities are specifically exempt from the stormwater management plan requirements of this Part:
Subdivision or land development which results in earth disturbance of three acres or less, or new impervious surfaces of 7,500 square feet or less. For parcels under single ownership, no more than three subdivisions or land developments will be permitted before requiring stormwater management plans in all subsequent cases.
Agriculture when operating in accordance with a conservation plan approved by the Conservation District.
Forest management operations which are following the Department of Environmental Protection management practices contained in its publication "Soil Erosion and Sedimentation Control Guidelines for Forestry" and are operating under an erosion and sedimentation control plan.
All existing and proposed structures, land disturbances and impervious surfaces.
All temporary and permanent, stormwater management controls.
All erosion and sedimentation controls.
The two-, ten- and one-hundred-year design storm frequencies shall be used for analyzing stormwater runoff in pre- and post-development conditions, as well as for designing runoff control facilities. The Soil Conservation Service twenty-four-hour total rainfall for these storm frequencies are:
Two-year storm - 2.14 inches of rainfall.
Ten-year storm - 3.23 inches of rainfall.
One-hundred-year storm - 5.72 inches of rainfall.
The release rate percentage for property in the Township shall be 100%. The developer's engineer shall compute the pre- and post-development hydrographs for each stormwater outfall draining the site, using the soil cover complex method in the Soil Conservation Service's Technical Manual No. 55, for the two-, ten- and one-hundred-year design storms. If the post development rate exceeds the pre-development value, then on-site stormwater detention will be required.
Detention facilities shall be designed to:
Be equipped with multi-stage outlet structures to handle the two-, ten- and one-hundred-year storm frequencies, and to pass larger storms without damage to the structure.
Minimize the effects of erosion on inflow and outflow structures.
Ease control and removal of debris from all parts of the facility.
Keep side slopes of water storage areas not steeper than one-foot vertical rise to each three feet horizontal. Steeper slopes may be allowed only if accompanied by a geotechnical report in a form and manner acceptable to the Township Engineer that demonstrates proposed stable slopes steeper than one-foot vertical to three feet horizontal.
Protect the storage area by surrounding it with a chain-link fence not less than four feet high, or other appropriate security measure acceptable by the Township Engineer.
The stormwater management plan shall establish responsibility for the continuing maintenance of all proposed stormwater control facilities in accordance with the requirements of § 26-207 of the Deer Creek Watershed Ordinance [Chapter 26, Part 2] (relating to responsibility for ownership, operation and maintenance of post-construction stormwater control facilities).
Completed stormwater management plans, accompanied by the requisite fees, are to be submitted to the Planning Commission for approval. The Commission shall notify the applicant within 45 days of its decision. A disapproval of an applicant's plan shall contain the reasons for the disapproval.
Immediately upon receipt of a stormwater management plan, the Township Secretary shall submit one copy to the Planning Commission and one copy to the Township Engineer for review. The Engineer shall submit a written review of the plan to the Planning Commission prior to the time set for hearing.
Provisions governing stormwater management which are adopted as part of the Subdivision and Land Development Ordinance [Chapter 22] and Zoning Ordinance [Chapter 27] shall remain in force unless inconsistent with the language of this chapter.
[Ord. 70, 5/4/1989, § 6]
During construction, the Township Engineer shall inspect the work in progress at least 48 hours before completion of each of the following tasks.
Preliminary site preparation.
Placing of structures.
Activation of the facility.
Final site restoration work.
No work shall begin on one task until the previous one has been completed to the Township Engineer's satisfaction. The costs of inspection incurred by the Engineer shall be borne by the developer. The Engineer shall inform the developer in advance of his rate and the estimated total cost of the work.
[Ord. 70, 5/4/1989, § 7]
The Board of Supervisors may by resolution adopt a schedule of fees to be paid by the applicant.
[Ord. 70, 5/4/1989, § 8; as amended by Ord. 153, 10/7/2008, § 1]
Improvement bonds or guarantees shall be required in accordance with the provisions of the Subdivision and Land Development Ordinance [Chapter 22], except as otherwise required under § 26-105.7 of this Part and § 26-207 of the Deer Creek Watershed Ordinance [Chapter 26, Part 2].
[Ord. 70, 5/4/1989; as added by Ord. 153, 10/7/2008, § 1]
General. The provisions of this Part are intended as minimum standards for the protection of the public health, safety and welfare. The Board of Supervisors may grant a waiver from literal compliance with mandatory provisions of the Part if the applicant can demonstrate either (A) that compliance would cause undue hardship as it applies to a particular party or (B) that an alternative proposal will allow for equal or better results.
Purpose and Conditions. The approval of the waiver shall not have the effect of making null and void the intent and purpose of this Part. In the approval of a waiver, the Board of Supervisors may impose such conditions as will, in its judgment, secure substantially the objectives of the purposes, standards and requirements of the Part, and the applicable purposes standards, and objectives of the Subdivision and Land Development Ordinance [Chapter 22].
Application Procedures. All requests for waivers shall be processed in accordance with the following:
A request for a waiver shall be submitted to the Zoning Officer on such form or forms prescribed from time to time by the Township. The request shall be made in writing and identify (1) the specific section of the Part or decision which is requested for waiver; (2) the proposed alternative to the requirement, when applicable, and (iii) justifications for an approval of the waiver.
The Township shall (1) schedule the request for consideration at a public meeting of the Board of Supervisors and (2) provide adequate notice to the applicant of the meeting at which consideration of the request is scheduled.
The Board of Supervisors shall, following the consideration of the request, take such public action as it shall deem advisable and transmit a written decision to the applicant.
[Ord. 70, 5/4/1989, § 9; as amended by Ord. 137, 7/5/2005; and by Ord. 153, 10/7/2008, § 1]
The Zoning Officer and any authorized representatives of the Township shall have the right to enter private property at reasonable times to inspect and/or investigate any condition associated with this Part.
Any person, firm or corporation who shall violate any provision of this Part, upon conviction thereof in an action brought before a district justice 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 less than $300 nor more than $1,000 plus costs, including reasonable attorneys fees incurred by the Township, 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.
In addition, the Township 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.
Any person aggrieved by any decision of the Township relative to the provisions of this Part may appeal the decision to the Allegheny County Court of Common Pleas within 30 days of the Township's decision.
[Ord. 153, 10/7/2008, § 2]
This Part shall be known and cited as the "Deer Creek Watershed Ordinance."
In order to protect the health, safety, and general welfare of the residents of the Township, as well as to protect, sustain, and enhance the surface and ground water resources of the Township, drainage and stormwater management practices shall be utilized as directed herein to achieve the following goals and objectives within the Deer Creek Watershed:
Accommodate site development and redevelopment in a manner that protects public safety and that is consistent with (or re-establishes) the natural hydrologic characteristics of each watershed and sustains ground water recharge, stream baseflows, stable stream channel (geomorphology) conditions, the carrying capacity of streams and their floodplains, ground water and surface water quality, and aquatic living resources and their habitats.
Reduce and minimize the volume of stormwater generated.
Protect natural infiltration and ground water recharge rates in order to sustain ground water supplies and stream baseflows.
Maintain runoff characteristics of the site after completion of development that are consistent with the carrying capacity and stable channel conditions of the receiving streams.
Ensure that the chemical, physical, and biological quality of ground and surface waters are protected by requiring appropriate management of stormwater pursuant to this Part.
Protect in-stream channels and geomorphology conditions of the receiving streams; protect their flood carrying capacity and aquatic habitats and to reduce in-stream erosion and sedimentation.
Reduce flooding impacts and prevent a significant increase in surface runoff rates and volumes, predevelopment to post-development, which could worsen flooding downstream in the watershed, enlarge floodplains, erode stream banks and create other flood-related health-welfare-property losses; in general, to preserve and restore the natural flood-carrying capacity of streams and their floodplains.
Protect adjacent lands from adverse impacts of direct stormwater discharges.
Ensure effective long-term operation and maintenance of all permanent stormwater management facilities.
Maintain natural drainage patterns and encourage the use of natural drainage systems.
Treat and release stormwater as close to the source of runoff as possible using a minimum of structures and maximizing reliance on natural processes.
Maintain the existing water balance in all watersheds, subwatersheds, and streams in the Township, and protect and/or restore natural hydrologic characteristics and habitats wherever possible throughout the watershed systems.
Address requirements of the Municipal Separate Storm Sewer System (MS4) National Pollution Discharge Elimination System (NPDES) Phase II Stormwater Regulations as applicable to the Township.
Reduce the impacts of runoff from existing developed sites undergoing redevelopment while encouraging development and redevelopment in urban areas and areas designated for growth.
Meet legal water quality requirements under applicable State law, including regulations at 25 Pa.Code, Chapter 93.4a, as amended, to protect and maintain "existing uses" and maintain the level of water quality to support those uses in all streams, and to protect and maintain water quality in "special protection" streams.
Minimize the potential for accelerated erosion and sedimentation from regulated activities.
AASHTO — American Association of State Highway and Transportation Officials.
The Allegheny County Conservation District or its successor.
The Allegheny County Health Department or its successor.
The Pennsylvania Storm Water Management Act, 32 P.S. § 680.1 et seq., as amended.
ACCELERATED EROSION AND SEDIMENTATION
The work of producing crops including 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.
The Department of Real Estate for Allegheny County or its successor.
ALLEGHENY COUNTY PLANNING AGENCY
The Allegheny County Department of Economic Development or its successor.
A landowner, developer or other person who has filed an application for approval to engage in any regulated earth disturbance activity at a project site in the Deer Creek Watershed.
To reduce the magnitude of the flow rate by increasing the time it takes to release a specified volume of runoff (for example the one-year, twenty-four-hour storm event). Attenuation is a method of reducing the peak flow rates for post development compared to the peak flow rates in predevelopment.
A geologic formation, group of formations, or part of a formation that contains sufficient saturated, permeable material to yield useful quantities of ground water to wells and springs.
Portion of stream discharge derived from ground water; the sustained discharge that does not result from direct runoff or from water diversions, reservoir releases, piped discharges, or other human activities.
Methods, measures or practices and facilities to prevent or reduce surface runoff and/or water pollution including, but not limited to, structural and nonstructural stormwater management practices and facilities and operation and maintenance procedures.
A natural or artificial watercourse that conveys, continuously or periodically, flowing water.
The Pennsylvania Clean Streams Law, 35 P.S. § 691.1 et seq., as amended.
A series of holistic land development design practices that maximize protection of key land and environmental resources, preserve significant concentrations of open space and greenways, evaluate and maintain site hydrology, and ensure flexibility in development design to meet community needs for complementary and aesthetically pleasing development. Conservation design encompasses the following objectives: conservation/enhancement of natural resources, wildlife habitat, biodiversity corridors and greenways (interconnected open space); minimization of environmental impact resulting from a change in land use (minimum disturbance, minimum maintenance); maintenance of a balanced water budget by making use of site characteristics and infiltration; incorporation of unique natural, scenic and historic site features into the configuration of the development; preservation of the integral characteristics of the site as viewed froth adjoining roads; and reduction in maintenance required for stormwater management practices. Such objectives can be met on a site through an integrated development process that respects natural site conditions and attempts, to the maximum extent possible, to replicate or improve the natural hydrology of a site.
A conservation district, as defined in § 3(c) of the Conservation District Law (3 P.S. § 851(c)), which has the authority under a delegation agreement executed with the Department to administer and enforce all or a portion of the erosion and sediment control program in this Commonwealth.
Surface runoff from rainfall events, which converges and flows primarily through water conveyance features such as swales, gullies, waterways, channels or storm sewers and which exceeds the maximum specified flow rates of filters or perimeter controls intended to control sheet flow.
The watershed area of the Township identified in Appendix 26-2-F of this Part.
The magnitude and temporal distribution of precipitation from a storm event measured in probability of occurrence (e.g., a five-year storm) and duration (e.g., 24-hours), used in the design and evaluation of stormwater management systems.
An impoundment designed to collect and retard stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate. Detention basins are designed to drain completely shortly after any given rainfall event and are dry until the next rainfall event.
As defined in the Subdivision and Land Development Ordinance [Chapter 22].
To release of water from a project, site, aquifer, drainage basin or other point of interest (verb); The rate and volume of flow of water such as in a stream, generally expressed in cubic feet per second (volume per unit of time) (noun).
An unstabilized land area where an earth disturbance is occurring or has occurred.
That land area contributing runoff to a single point and that is enclosed by a ridge line.
All facilities and natural features used for the movement of stormwater through and from a drainage area, including, but not limited to, any and all of the following; conduits, pipes and appurtenant features: channels, ditches, flumes, culverts, streets, swales, gutters as well as all watercourses, water bodies and wetlands.
Environmental Protection Agency or its successor.
A construction or other human activity which disturbs the surface of the land, including, but not limited to, clearing and grubbing; wading; excavations; embankments; road maintenance; building construction; the moving, depositing, stockpiling, or storing of soil, rock or earth materials.
A right of use of a specified portion of land of another for a specified purpose.
The wearing away of land surface by water or wind which occurs naturally from weather or runoff, but is often intensified by human activity.
Federal Emergency Management Agency or its successor.
The channel of the watercourse and those portions of the adjoining floodplains that is reasonably required to carry and discharge the one-hundred-year flood. Unless otherwise specified, the boundary of the floodway is as indicated on maps and flood insurance studies provided by FEMA. In an area where no FEMA maps or studies have defined the boundary of the one-hundred-year floodway, it is assumed, absent evidence to the contrary, that the floodway extends from the stream to 50 feet from the top of the bank of the stream.
Upper-most perennial tributary in a watershed that has not yet confluenced with another perennial stream. The confluence of two first order streams forms a "second" order stream.
The difference between the elevation of the design flow in the emergency spillway (usually the one-hundred-year peak elevation) and the top elevation of the settled basin embankment (that is, top of berm). The minimum freeboard shall be one foot.
Infiltration rates of soils vary widely and are affected by subsurface permeability as well as surface intake rates. Soils are classified into four HSG's (A, B, C, and D) according to their minimum infiltration rate, which is obtained for bare soil after prolonged wetting. The Natural Resources Conservation Service (NRCS) of the US Department of Agriculture defines the four groups and provides a list of most of the soils in the United States and their group classification. The soils in the area of the development site may be identified from a soil survey report that can be obtained from local NRCS offices or conservation district offices. Soils become less pervious as the HSG varies from A to D.
The study of the properties, distribution, circulation and effects of water on the earth's surface, soil and atmosphere.
A graph of discharge versus time for a selected point in the drainage system.
A surface (area), which has been compacted or covered with a layer of material so that it is resistant to infiltration by water. It includes semi-pervious surfaces such as compacted clayey soils, as well as most conventionally surfaced streets, roofs, sidewalks, parking lots, and other similar surfaces. Net increase of impervious surface refers to the difference between the existing impervious coverage and the total impervious surface proposed.
Movement of surface water into the soil, where it is absorbed by plant roots, evaporated into the atmosphere, or percolates downward to recharge ground water.
A defined channel in which surface water is absent during a portion of the year, as ground water levels drop below the channel bottom.
A type of topography that is formed over limestone or other carbonate rock formations by dissolving or solution of the rock by water, and that is characterized by closed depressions, sinkholes, caves, a subsurface network of solution conduits and fissures through which ground water moves, and no perennial surface drainage features.
A low earthen berm constructed perpendicular to the direction of slope and extending across the width of the slope for the purpose of intercepting surface runoff and spreading it behind the berm to enhance infiltration and reduce erosion and runoff from the slope. The purpose of a level spreader is to prevent concentrated, erosive flows from occurring and to spread out stormwater runoff uniformly over the ground as sheet flow.
The total amount (generally measured in pounds or kilograms per acre per year) of material (sediment, nutrients, oxygen-demanding material, or other chemicals or compounds) brought into a lake, stream or water body by inflowing streams, runoff, direct discharge through pipes, ground water, the air (aerial or atmospheric deposition) and other sources over a specific period of time (often annually).
A natural ground cover with less than one viable tree of a DBH of six inches or greater per 1,500 square feet within 10 years of application; a cover condition for which SCS curve numbers have been assigned or to which equivalent rational method runoff coefficients have been assigned.
National Oceanic and Atmospheric Administration or its successor.
Natural Resources Conservation Service or its successor.
Created in 1972 under the Clean Water Act to authorize discharges to local receiving waters only pursuant to governmental permits, in an effort to reduce point source and non-point source pollutants.
Any activity regulated by this Part that is not considered a redevelopment as defined in this Part.
NON-STRUCTURAL STORMWATER MANAGEMENT PRACTICES
Passive, site design approaches or regulatory approaches that positively impact water quality and reduce or minimize the generation of stormwater runoff without requiring the construction of specific or discrete stormwater management control structures.
Any natural or man-made watercourse or conduit in which water flows with a free surface.
Also known as swales, grass channels, and biofilters. These systems are used for the conveyance, retention, infiltration and filtration of stormwater runoff.
The Department of Environmental Protection of the Commonwealth of Pennsylvania or its successor.
A ground cover of grassland or range with continuous forage for grazing and greater than 75% ground cover and lightly or only occasionally grazed; a cover condition for which the Soil Conservation Service curve numbers have been assigned or to which equivalent rational method runoff coefficients have been assigned.
The Department of Transportation of the Commonwealth of Pennsylvania or its successor.
The rate of movement of water under hydrostatic pressure through interstices of rock or soil. For stormwater analysis, it is typically measured as a distance per unit of time (e.g., inches per hour).
The ground cover assumption used when analyzing the stormwater runoff characteristics of a drainage area prior to the proposed development.
The specific area of land where any regulated activities in the Township are planned, conducted or maintained.
Any person licensed by the Pennsylvania Department of State or otherwise qualified by law to perform the work required by this Part, including a professional engineer, a professional landscape architect, and a professional land surveyor.
Any water bodies, watercourses or wetlands into which surface waters flow.
An existing, developed property and/or a graded, altered and compacted site (as of or after the date of adoption of this Part) that is proposed for reconstruction involving the demolition or partial demolition of the property.
Any earth disturbances or any activities that involve the alteration or development of land in a manner that may affect post construction stormwater runoff.
Activity involving earth disturbance subject to regulation under 25 Pa. Code, Chapter 92, Chapter 102, or the Clean Streams Law.
The percentage of predevelopment peak rate of runoff from a watershed subarea (as delineated in the Act 167 watershed plan), which defines the allowable post-development peak discharge from any development site in that subarea.
The prevention of direct discharge of stormwater runoff into receiving waters or water bodies by temporary or permanent containment in a pond or depression; examples include systems which discharge by percolation to ground water, exfiltration, and/or evaporation processes and which generally have residence times of less than three days.
The average interval, in years, within which a storm event of a given magnitude can be expected to occur one time. For example, the twenty-five-year return period rainfall would be expected to occur on average once every 25 years.
An area of land adjacent to a body of water and managed to maintain the integrity of stream channels and shorelines to (A) reduce the impact of upland sources of pollution by trapping, filtering and converting sediments, nutrients and other chemicals, and (B) supply food, cover and thermal protection to fish and other wildlife.
Soil Conservation Service or its successor.
Fragmented material that originated from weathering rocks and decomposing organic material that is transported by, suspended in, and eventually deposited in the streambed.
Occurs when sediment particles that have been suspended within flowing water are deposited on the stream bottom or floodplain.
Source loading and management model. This model is based on small storm hydrology and pollutant runoff from urban land uses. Pollutant sources are identified and both structural and nonstructural stormwater practices can be accounted for in the model.
Those areas identified by the FEMA, Federal insurance administration (FIA) as floodway area (FW), flood fringe area (FF), and general floodplain area (FA); where determined by the Township, identified alluvial soils may be included as well.
The regulatory requirements to protect, maintain, reclaim, and restore water quality under Pennsylvania Code, Title 25, and the Clean Streams Law.
See "Act 167."
The approved detailed analysis, design, and drawings of the stormwater management system required under this Part.
The designed and/or constructed features which infiltrate, treat, collect, convey, channel, store, inhibit, or divert the movement of stormwater; such practices include structural and non-structural practices.
Any measures that require the design and construction of a facility to help reduce or eliminate a non-point source of pollution and control stormwater.
Anything constructed or installed with a fixed location on the ground, or attached to something having a fixed location on the ground.
A portion of the watershed (basin) that has similar hydrological characteristics and drains to a common point.
The top elevation of graded and compacted earth underlying roadway pavement.
An artificial or natural waterway which may contain contiguous areas of standing or flowing water only following a rainfall event, or is planted with or has stabilized vegetation suitable for soil stabilization, stormwater treatment, and nutrient uptake, or is designed to take into account the soil erodibility, soil percolation, slope, slope length, and contributing drainage area so as to prevent erosion and reduce the pollutant concentration of any discharge.
Stormwater management model. EPA developed this model for analyzing stormwater quantity and quality associated with runoff from urban areas. Both single event and continuous simulation can be performed on catchments having storm sewers, or combined sewers and natural drainage, for prediction of flows, stages and pollutant concentrations.
The Township of Frazer, Allegheny County, Pennsylvania.
The professional engineer licensed as such in the Commonwealth of Pennsylvania and duly appointed as the engineer of the Township or his designee.
United States Department of Agriculture or its successor.
United States Department of Transportation Federal Highway Administration or its successor.
Any natural or artificial pond, lake, reservoir, or other area which ordinarily or intermittently contains water and which has a discernible shoreline and receives surface water flow.
A permanent or intermittent stream or other body of water, whether natural or man-made, which gathers or carries surface water.
The upper most level of saturation of pore space or fractures by subsurface water in an aquifer. Seasonal high water table refers to a water table that rises and falls with the seasons due either to natural or man-made causes.
Land area that drains to a common water body or downstream point.
Land areas that are inundated or saturated by surface or groundwater with a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions (wetlands generally include swamps, marshes, bogs, and similar areas); or areas that are defined and delineated in accordance with the Federal Manual for Identifying and Delineating Jurisdictional Wetlands, dated January 10, 1989, and as may be amended from time to time; or as further defined and delineated by the United States Army Corps of Engineers, the United States Environmental Protection Agency, or the Pennsylvania Department of Environmental Protection.
A natural ground cover with more than one viable tree of a DBH (diameter at breast height) of six inches or greater per 1,500 square feet which existed within 10 years of application; a cover condition for which SCS curve numbers have been assigned or to which equivalent rational method runoff coefficients have been assigned.
The individual authorized by the Board of Supervisors to be the administrator of the day-to-day application of the provisions in this Part.
Chapter 27 of the Frazer Township Code of Ordinances, as amended.
Primary Authority. The Township is empowered to regulate stormwater pursuant to the Pennsylvania Stormwater Management Act (commonly referred to as Act 167), and § 2704 of the Pennsylvania Second Class Township Code, 53 P.S. § 67704, as amended.
Secondary Authority. The Township also is empowered to regulate land use activities that affect stormwater pursuant to the Municipalities Planning Code, 53 P.S. § 10101 et seq.
The standards contained herein shall apply to all regulated activities within the Deer Creek Watershed. In addition, all Township, County and State erosion and sedimentation control approvals must be in place to proceed with any regulated activity within the Deer Creek Watershed.
Regulated activities (as defined in § 26-203 of this Part) regulated by this Part include, but are not limited to, the following:
Construction of new or additional impervious or semi-pervious surfaces (including driveways and parking lots).
Any earth disturbances or any activities that involve the alteration or development of land or removal of tree and vegetation in a manner that may affect post construction stormwater runoff.
Redevelopments shall conform to the requirements contained in § 26-206.1 when more than a 2,000 square feet area of an existing facility are reconstructed, following the demolition, or partial demolition of the existing facility. The area determination shall be made using the footprint of the area being reconstructed, including all impervious surfaces proposed in the reconstructed area and the area of the parking lot required to support the reconstructed facility. The area of the parking lot required to support the reconstructed facility shall be determined using the Zoning Ordinance [Chapter 27] requirements for parking.
Exemptions. The following regulated activities are exempted from the requirement for on-site stormwater facilities and the preparation of a stormwater management plan. All other stormwater management design elements, such as a storm sewer system, road culverts, erosion and sedimentation control, and runoff quality, are required. The Township Engineer may require implementation of on-site stormwater facilities and/or the preparation of a stormwater management plan if he/she believes the facilities and/or stormwater management plans are reasonably necessary to prevent flooding or protect surface water or groundwater of the Township.
Regulated activities smaller than 400 square feet are exempt from the requirements of this Part to implement SWM BMPs, unless the activity is found to be a significant contributor to pollution of the waters of this Commonwealth.
Small Project Exemption. Activities having a disturbed area of less than 5,000 square feet are exempt from the peak rate control requirements of this Part. These projects shall comply with the water quality volume standards contained in § 26-206.3.A(1)(b) and the extended detention requirement contained in § 26-206.3.A(1)(a). The "Small Project Standardized SWM Guidance" document provided in Appendix 26-2-E was prepared to assist applicants in meeting this requirement for individual lots only. The reduced site plan requirements contained in the "Small Project Standardized SWM Guidance" document shall apply.
Emergency Exemption. Emergency maintenance work performed for the protection of public health, safety and welfare may be exempted from the requirements in this Part to obtain approval for a stormwater management plan before commencement of the activity; however, a written description of the scope and extent of any emergency work performed shall be submitted to the Township within two calendar days of the commencement of the activity. If the Township finds that the work is not an emergency, then the work shall cease immediately and may not resume until a written stormwater management plan is submitted to and approved by the Township.
Maintenance Exemption. Any maintenance to an existing stormwater management system made in accordance with plans and specifications approved by the Township Engineer or the Township.
Agricultural Activities. Agriculture when operated in accordance with a conservation plan, nutrient management plan or erosion and sedimentation control plan approved by the ACCD, including activities such as growing crops, rotating crops, tilling of soil and grazing animals. Installation of new or expansion of existing farmsteads, animal housing, waste storage and production areas having impervious surfaces that result in a net increase in impervious surface of less than 1,000 square feet are exempt from the requirement to submit a written stormwater management plan.
Forest Management. Forest management operations, which are consistent with a sound forest management plan as filed with the Zoning Officer and which comply with: (1) applicable provisions of the Zoning Ordinance [Chapter 27] and Subdivision and Land Development Ordinance [Chapter 22]; and (2) the PADEP's management practices contained in its publication "Soil Erosion and Sedimentation Control Guidelines for Forestry." Such operations are required to have an erosion and sedimentation control plan as well as a Township timber harvesting permit.
Roads. Earth disturbance including road maintenance activities within the right of way of existing public roads.
The provisions of this Part are the minimum standards for the protection of the public health, safety, property, and welfare.
If an applicant demonstrates to the satisfaction of the Township or its designee that any mandatory provision of this Part is unreasonable or causes unique or undue hardship as it applies to the proposed project, or that an alternate design may result in a superior result within the context of §§ 26-202, 26-206.1.A, and 26-206.1.B of this Part, the Township or its designee upon obtaining the comments and recommendations of Township the ACCD may grant a waiver or relief so that substantial justice may be done and the public interest is secured; provided that such waiver will not have the effect of nullifying the intent and purpose of this Part.
Applicants shall refer to the "Pennsylvania Stormwater Best Management Practices Manual," Pennsylvania Department of Environmental Protection No. 363-0300-002 (2006), as amended and updated, or the "Erosion and Sediment Pollution Control Program Manual," Pennsylvania Department of Environmental Protection No. 3632134-008 (2000), as amended and updated, or other appropriate references for guidance in the design of stormwater management facilities most appropriate to individual site conditions. References to the Maryland Manual, if not deleted, should be to specific sections of Maryland's manual in order to minimize NPDES permitting conflicts with the guidance provided by the Pennsylvania Stormwater BMP Manual. The applicant shall state in full the facts of unreasonableness or hardship on which the request is based, the provision or provisions of the Part 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 of §§ 26-102, 26-106.1.A, and 26-106.1.B of this Part.
The applicant shall submit all waiver requests to the Township Board of Supervisors or its designee for review and approval.
The Township shall keep a written record of all actions on waiver requests.
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, the County and the ACCD for reasonable and necessary fees that may be incurred in any review of a waiver request.
In granting waivers, the Township or its designee may impose reasonable conditions that will, in its judgment, secure substantially the objectives of the standards or requirements that are to be modified.
The Township or its designee may grant applications for waivers when all of the following findings are made:
That the waiver shall result in an equal or better means of complying with the intent of §§ 26-202, 26-206.1.A, and 26-206.1.B of this Part.
There will be no increase in the rate of the post-development total runoff volume for all storms equal to or less than the two-year/twenty-four-hour storm event.
That the amount of stormwater generated has been minimized to the greatest extent practicable.
That infiltration of runoff throughout the proposed site has been provided where practicable and pre-development ground water recharge protected at a minimum.
That long term operation and maintenance activities are established.
That no receiving streams and/or water bodies within 2,000 feet downstream will be significantly adversely impacted in flood carrying capacity, aquatic habitat, channel stability or erosion and sedimentation.
The management of stormwater on site, both during and upon completion of the disturbances associated with activities permitted under subsection .2, shall be accomplished in accordance with the standards and criteria of this Part. The design of any temporary or permanent facilities and structures and the utilization of any natural drainage systems shall be in full compliance with this Part.
The intent of the design standards contained in this Part is to encourage environmentally sound stormwater management practices that provide necessary drainage facilities while protecting the hydrologic characteristics and water quality of the site and watershed.
Developments shall be required to incorporate stormwater management controls.
Stormwater management design shall blend into the natural environment and be aesthetically integrated into the site design.
Applicants shall refer to the "Pennsylvania Stormwater Best Management Practices Manual," as amended, "Pennsylvania Handbook of Best Management Practices for Developing Areas" (PACD, 1998), the 2000 "Maryland Stormwater Design Manual" (MDE, 2000) or other appropriate references for guidance in the design of stormwater management facilities most appropriate to individual site conditions. Objectives for design are to reduce the volume of stormwater generated, infiltrate runoff at its source to the maximum extent possible, achieve water quality improvement at the source or during conveyance, and provide for peak flow attenuation. Applicants shall examine design alternatives by viewing them in a series. In addition, applicants are strongly encouraged to use structural and nonstructural stormwater management practices that reduce or eliminate the need for detention basins.
All SWM design work must be completed by a qualified design professional. All designs proposing the use of a SWM retention or detention facility with outlet structure(s) shall be completed by an engineer.
All development activity within a special flood hazard area designated by the Federal Emergency Management Agency (FEMA) shall comply with Chapter 8 of the Frazer Township Code of Ordinances, Floodplains, as amended, and this paragraph. All development shall be designed to maintain the flood carrying capacity of the floodway such that the base flood elevations are not increased, either upstream or downstream, unless an approval is received from PADEP. The natural conveyance characteristics of the site and the receiving floodplain shall be incorporated into the stormwater management practices proposed for the site.
The stormwater management system shall not create an adverse impact on stormwater quantity or quality in either upstream or downstream areas. Off-site areas which discharge to or across a site proposed for development shall be addressed in the stormwater management plan prepared for the development. No stormwater management plan shall be approved until it is demonstrated that the runoff from the project shall not significantly adversely impact downstream areas.
All proposed stormwater management systems shall be designed to prevent the pollution of ground water resources by stormwater, promote safety, minimize health hazards, preserve natural features and provide infiltration and ground water recharge where appropriate. Neither submission of a plan under the provision herein nor compliance with the provisions of these regulations shall relieve any person from responsibility for damage to any person or property otherwise imposed by law.
Where deemed necessary by the Township Engineer, or as addressed in an approved Act 167 stormwater management plan, the applicant shall construct storm drains to handle on-site runoff; provide on-site/off-site drainage easements to the maximum extent permitted under the Municipalities Planning Code and Act 167, or any amendments thereto; and provide for the conveyance of off-site runoff to an acceptable outlet in the same watershed.
For all regulated activities, stormwater management BMPs shall be designed, implemented, operated, and maintained to meet the purposes and requirements of this Part and to meet all requirements under Pennsylvania Code, Title 25, the Clean Streams Law, and the Storm Water Management Act.
Any regulated activity that may affect the stormwater discharges toward or onto a State or County highway right-of-way or facility shall be designed, implemented, operated, and maintained in accordance with the regulations of PennDOT or Allegheny County, as the case may be.
At the time of application for a building permit for any approved lot created by a subdivision and/or improved as a land development project, issuance of the permit shall be conditioned upon adherence to the terms of this Part.
Stormwater discharges to critical areas with sensitive resources (e.g., special protection waters, cold water fisheries, recharge areas, water supply reservoirs, etc.) may be subject to additional performance criteria or may need to utilize or restrict certain stormwater management practices.
For all regulated earth disturbance activities, erosion and sediment control BMPs shall be designed, implemented, operated, and maintained during the regulated earth disturbance activities (e.g., during construction) to meet the purposes and requirements of this Part and to meet all requirements under the Pennsylvania Code, Title 25, and the Clean Streams Law, including permits, where applicable. Various BMPs and their design standards are listed in the "Erosion and Sediment Pollution Control Program Manual" (E&S Manual), Commonwealth of Pennsylvania, Department of Environmental Protection, No. 363-2134-008, as amended and updated.
No regulated earth disturbance activities within the Deer Creek Watershed Area of the Township shall commence until the requirements of this Part are met.
Post-construction water quality protection shall be addressed as required by the stormwater management requirements contained in this Part.
Operations and maintenance of permanent stormwater BMPs shall be addressed as required by § 26-207.
All best management practices (BMPs) used to meet the requirements of this Part shall conform to the State water quality requirements, and any more stringent requirements as required by the Township.
Techniques described in Appendix 26-2-B (Non-Structural Stormwater Management Practices) of this Part are encouraged, because they reduce the costs of complying with the requirements of this Part and the State water quality requirements.
Transference of runoff from one PADEP designated Act 167 watershed to another shall be prohibited unless approved by the Township.
Severability. Should any section or provision of this Part be declared invalid by a court of competent jurisdiction, such determination of invalidity shall not affect the validity of the remaining provisions of this Part.
Compatibility with Other Requirements. Permits and approvals issued pursuant to this Part shall not relieve the applicant of the responsibility to comply with or to secure other required permits or approvals for activities regulated by any other applicable code, rule, act, statute or ordinance. This Part shall not preclude the inclusion in such other permit of more stringent requirements concerning regulation of stormwater and erosion within the Deer Creek Watershed. Where a conflict exists between a provision within this Part and that of the PADEP Phase II NPDES regulations, as amended, or any other ordinance of the Township applicable to the Deer Creek Watershed, the more stringent requirements shall govern.
All regulated earth disturbance activities subject to permit requirements by PADEP under regulations at 25 Pa.Code, Chapter 102.
Any stormwater management facility that would be located in or adjacent to surface waters of the Commonwealth, including wetlands, subject to permit by PADEP under 25 Pa.Code, Chapter 105.
Any stormwater management facility that would be located on a State highway right-of-way, or require access from a State highway, shall be subject to approval by PennDOT.
Culverts, bridges, storm sewers or any other facilities which must pass or convey flows from the tributary area and any facility which may constitute a dam subject to permit by PADEP under 25 Pa.Code, Chapter 105.
No regulated earth disturbance activities within the Deer Creek Watershed shall commence until the Township receives a copy of any required approvals from the ACCD or PADEP for an erosion and sediment control plan.
PADEP has regulations that require an erosion and sediment control plan for any earth disturbance activity of 5,000 square feet or more, under 25 Pa.Code § 102.4(b).
In addition, under 25 Pa.Code, Chapter 92, a PADEP "NPDES Construction Activities" permit is required for certain regulated earth disturbance activities.
Evidence of any necessary permit(s) for regulated earth disturbance activities from PADEP or ACCD must be provided to the Township.
A copy of the erosion and sediment control plan and any required permits, as required by PADEP regulations, shall be available at the project site at all times.
Areas proposed for infiltration BMPs shall be protected from sedimentation and compaction during the construction phase to maintain design infiltration capacity.
No person in the Deer Creek Watershed shall allow, or cause to allow, stormwater discharges into the Township's separate storm sewer system and/or waters of this Commonwealth which are not composed entirely of stormwater, except (1) as provided in subsection .11.B below, and (2) discharges allowed under a State or Federal permit.
The following discharges are authorized unless they are determined to be significant contributors to pollution to the waters of this Commonwealth:
In the event that the Township determines that any of the discharges identified in subsection .11.B significantly contribute to pollution of waters of the Commonwealth, or is so notified by PADEP, the Township or PADEP will notify the responsible person to cease the discharge.
Existing roof drain, underdrain and sump pump discharges should be directed to lawn area or other pervious areas where feasible and consistent with good engineering practice. If required by the Township, the discharge shall be directed to a stone sump or infiltration BMP. If approved by the Township, the discharge may also be directly connected to the storm sewer system.
Right-of-Entry. The Zoning Officer and any authorized representative of the Township shall have the right to enter any property within the Township at reasonable times to inspect and/or investigate any condition associated with this Part.
Inspection. SWM BMPs should be inspected by the land owner/developer (including Township for dedicated facilities) according to the following list of frequencies:
During or immediately after the cessation of a ten-year or greater storm event.
It shall be unlawful for a person to undertake any regulated activity except as provided in an approved SWM plan.
It shall be unlawful to alter or remove any control structure required by the SWM plan.
Inspections regarding compliance with the SWM plan are a responsibility of the Township.
Any approval for a regulated activity issued may be suspended or revoked, in whole or in part, by the Township for:
Non-compliance with or failure to implement any provision of the approval.
A violation of any provision of this Part or any other applicable law, ordinance, rule or regulation relating to the regulated activity.
A suspended approval may be reinstated by the Township when:
The Township is satisfied that the violation has been corrected or will be corrected according to an enforceable schedule agreed to by the Township.
An approval that has been revoked by the Township may be reinstated, or the Township may require the applicant to apply for a new approval under the provisions of this Part.
Prior to revocation or suspension of a permit, if there is no immediate danger to life, public health, or property, the Township may notify the land owner/developer to discuss the non-compliance.
Penalties. Any person, firm or corporation who violates any provision of this Part, or fails to comply therewith, or with any of the requirements thereof, upon conviction thereof in an action brought before a magisterial district judge in the manner provided for the enforcement of summary offenses under the Pennsylvania Rules of Criminal Procedures, shall be sentenced to pay a fine of not less than $300 nor more than $1,000 plus costs, including reasonable attorney fees incurred by the Township, and in default of said fine and costs, to a term of imprisonment to the extent permitted by law for the punishment of summary offenses. A separate offense shall arise for each day or portion thereof in which a violation of this Part is found to exist or for each section of this Part is found to have been violated. The Township may also commence appropriate actions in equity or otherwise to prevent, restrain, correct, enjoin, or abate violations of this Part. All fines and penalties collected for violation of this Part shall be paid to the Township Treasurer. The initial determination of violation and the service of any required notice of violation are hereby delegated to the Township Manager, the Township Code Official/Building Inspector, the Code Enforcement Officer, the Zoning Officer and their designees and to any other officer or agent that the Township Secretary or the Board of Supervisors shall deem appropriate.
Appeals. Any person aggrieved by any decision of the Township, relevant to the provisions of this Part, may appeal to the Allegheny County Court of Common Pleas within 30 days of the Township's decision.
For all regulated activities not eligible for exemptions pursuant to § 26-204.3 of this Part, the applicant shall submit to the Township a stormwater management plan and report prepared by an engineer, which shall contain, but not be limited to, the following. Final copies of all plans, specifications and reports shall also be submitted to the Township in Adobe PDF electronic format.
A suitable map of the watershed for any and all named streams within which the project is proposed (a United States Geological Survey quadrangle map is usually sufficient) with existing and proposed development areas presented on the map.
Hydrologic (watershed) and water feature boundaries, including all areas flowing to the proposed project, existing streams (including first order and intermittent streams), springs, lakes, ponds, or other bodies of water within the project area.
Notes pertaining to and locations of existing standing water, areas of heavy seepage, springs, wetlands, streams, and hydrologically sensitive areas. The Chapter 93, Water Quality Standards, use designation must also be provided on the plan.
Description of current and proposed ground cover and land use. The total area and percent impervious cover shall be noted.
The design computations for all proposed stormwater drainage systems, including storm-drain pipes, inlets, runoff control measures and culverts, drainage channels, and other features, facilities, and stormwater management practices.
A grading plan, including all areas of disturbance of the subject activity. The total area of disturbance shall be noted in square feet and acres. Topographic contours showing the existing and proposed final contours at an interval of two feet; in areas having slope of greater than 15%, a five-foot contour interval may be used.
A plan, of the erosion and sedimentation procedures to be utilized as required by applicable Township, Allegheny County and State laws, statutes, ordinances and regulations.
An operation and maintenance plan consistent with the requirements of § 26-207. Such a plan should clearly explain how the proposed facilities operate and the functions they serve.
A north arrow, submission date, graphic scale and revision dates as applicable shall be included on each page of all plans submitted.
Complete delineation of the flow paths used for calculating the time of concentration for the pre-developed and post-developed conditions.
Construction details sufficient to completely express the intended stormwater design components consistent with this Part.
A listing of all permits required for the site providing the status of the permit application(s) and approval(s).
All existing and proposed easements and rights of way for drainage and/or stormwater control facilities shall be shown and the proposed owner identified. Show any areas subject to special deed restrictions relative to or affecting stormwater management on the development site.
Design Goals, Principles and Standards.
Design Goals. Applicants shall adhere to a holistic design process incorporating the goals listed below. The objective is to achieve post-development hydrologic conditions that are consistent with the predevelopment ground cover assumption for new development (refer to subsection .2.A(2)) and improve the runoff conditions for redevelopment (refer to subsection .2.E). The design goals are:
Minimize the volume of runoff that must be collected, conveyed, treated and released by stormwater management facilities.
Maintain the natural infiltration process and rate, and infiltrate runoff at its source when appropriate.
Remove and/or treat pollutants at the source or during conveyance through the application of best management practices.
Provide for peak flow attenuation, as needed.
Attenuate runoff to protect the in-stream channel of the receiving stream.
General Principles. The following general principles apply to all regulated activities pursuant to § 26-204.2.
Incorporate conservation design practices to minimize the amount of stormwater generated on a site, encourage the disconnection of impervious land cover, and maximize the use of pervious areas for stormwater treatment and on-site rainfall infiltration.
Infiltration of surface water runoff at its source is to be a mechanism for stormwater management based on hydrologic soil group (or infiltration testing). Infiltration practices include, but are not limited to, those referenced in subsection .3.B(1) and as outlined in the publications listed in subsection .3. Infiltration practices shall adhere to the following criteria:
Discourage concentration of flows.
Encourage disconnection of flows.
Infiltrate as close to the source of runoff as possible.
Where high water tables, subsurface contamination, slope stability concerns, or other site constraints preclude achieving the required infiltration volume, additional conservation design practices and alternative stormwater management practices should be implemented to reduce to the maximum extent practicable the total volume of stormwater released to streams. Applicant shall follow the stormwater runoff hierarchy of subsection .3.A(1)(a).
Infiltration areas should be designed to maintain any broad and even infiltration pattern which existed prior to development. Such facilities should use the natural topography and vegetation in order to blend in with the site. Infiltration designs, which do not provide this may be used if the applicant demonstrates to the Township's satisfaction that alternative approaches would be more effective, more harmonious with their existing environment and as easily maintained.
Aboveground stormwater infiltration facilities should be as shallow as possible while still achieving the requirements of this Part.
Water quality improvement shall be the goal to be achieved in conjunction with or as part of infiltration practices. Water quality improvements shall also be provided for drainage areas not otherwise addressed by infiltration practices either at the source of runoff and/or during conveyance away from the source of runoff.
When designing stormwater management facilities to satisfy the peak flow attenuation and extended detention requirements (refer to subsection .1.D(2)), the effect of structural and non-structural stormwater management practices implemented as part of the overall site design may be taken into consideration when calculating total storage volume and release rates.
Site hydrology and natural infiltration patterns shall guide site design, construction and vegetation decisions. All channels, drainageways, swales, natural streams and other surface water concentrations shall be considered and where possible incorporated into design decisions.
The following minimum performance standards shall apply to all regulated activities, whether they are new development or redevelopment, pursuant to § 26-204.2.
Water quality management shall be provided through the use of structural and/or non-structural stormwater management practices. Water quality stormwater management practices shall be designed to reduce or eliminate solids, sediment, nutrients, and other potential pollutants from the site. It is presumed that a stormwater management practice complies with this requirement if it is:
Designed according to the specific performance criteria outlined in § 26-204.5.B.
Constructed in accordance with all permits and approved plans and specifications.
Maintained per an approved operation and maintenance plan or agreement or, in lieu of that, in accordance with customary practices.
Stormwater discharges from land uses or activities with higher potential for pollutant loadings (hotspots) may require the use of specific structural stormwater management practices and pollution prevention practices. In addition, stormwater from a hotspot land use shall be provided with proper pretreatment prior to infiltration. For the purpose of this Part, the sites/facilities listed in subsection .3.C(1)(d) below, are considered hotspots.
Certain industrial sites 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. Other industrial sites storing significant quantities of chemicals/wastes should also prepare a prevention plan. Sites that are required by EPA to prepare a plan include, but are not limited to:
Fleet storage areas for buses, trucks etc.
Conveyance structures/channels shall be designed and adequately sized so as to protect the properties receiving runoff from impacts of flooding and erosion. Where necessary, and to the maximum extent permitted under the Municipalities Planning Code and Act 167, or any amendments thereto drainage easement from adjoining properties shall be obtained to ensure the drainage way and the property and shall also establish the operation and maintenance requirements for the drainage way.
All stormwater management practices shall have an operation and maintenance plan pursuant to § 26-207.3 of this Part, and if to be privately owned, an enforceable operation and maintenance agreement per § 26-207.4 of this Part to ensure the system functions as designed and to provide remedies for system failure.
Stormwater runoff generated from development and discharged directly into wetlands or waters of the United States and their adjacent wetlands shall be treated by an approved stormwater management practice prior to release into a natural wetlands and shall not be used to meet the minimum design requirements for stormwater management or stormwater runoff quality treatment, except when used as part of a treatment train that incorporates a portion of the outer zone (filter strip) of the wetland's riparian buffer as a stormwater outfall. In such instances, the discharge velocity from the terminal end of a pipe or associated energy dissipation practice shall not exceed two feet per second for the two-year frequency storm event. Where such a management strategy is used, all feasible methods shall be used to convert concentrated flow to uniform, shallow sheet flow before entering the outer zone of the wetlands' riparian buffer. In addition, it shall be demonstrated that such an approach will not cause erosion.
The following minimum performance standards shall apply to all new development regulated activities, pursuant to § 26-204.2.A.
Water quality improvement shall be the goal in conjunction with or as part of infiltration practices (if used). Water quality improvements shall also be provided for drainage areas not otherwise addressed by infiltration practices either at the source of runoff and/or during conveyance away from the source of runoff. Stormwater quality management practices shall be designed to capture and treat stormwater runoff generated by the one-inch rainfall event. Refer to subsection .3.A.(1)(b) for water quality volume design standards and assumptions. Stormwater quality management practice selection, design and implementation shall be based upon appropriate reference materials, as provided in § 26-204.5.B.
The post development peak discharge rate shall not exceed the predevelopment peak discharge rate multiplied by the "subbasin release rate percentage" (where determined in Act 167 watersheds) for the two-, ten-, twenty-five-, and one-hundred-year twenty-four-hour storm events pursuant to the predevelopment cover assumption described in subsection .2.A(2). Refer to Appendix 26-2-A for release rate percentages information.
Facilities capable of attenuating rainfall runoff shall be provided and be designed to attenuate the runoff volume from the one-year twenty-four-hour storm event for at least 24 hours.
Structural and non-structural stormwater management practices that make best possible use of infiltration on-site shall be considered in all site designs, when appropriate.
The following minimum performance standards shall apply to all redevelopment regulated activities, pursuant to § 26-204.2.B.
One of the following minimum performance standards shall be accomplished. Selection of the performance standard shall be whichever is most appropriate for the given site conditions:
Reduce the total impervious cover on the site (e.g., by using pervious pavement, replacement of pavement with pervious planting areas or green roof systems) by at least 25%, based on a comparison of existing impervious cover to proposed impervious cover.
Provide facilities designed to attenuate the runoff volume from the one-year twenty-four-hour post development storm event for at least 24 hours.
Provide facilities to insure that the post development peak discharge rate shall not exceed the predevelopment peak discharge rate multiplied by the "subbasin release rate percentage" (where determined in Act 167 watersheds) for the two-year and ten-year twenty-four-hour storm events. A predevelopment cover CN of 71 shall be assumed.
In addition to the minimum performance standards for redevelopment areas in subsection .1.E above, water quality improvements shall be provided for drainage areas not otherwise addressed by infiltration practices either at the source of runoff and/or during conveyance away from the source of runoff. Stormwater quality management facilities shall be designed to capture and treat 0.25 inch of runoff from all pavement areas (i.e., parking lots, pavements and non-covered sidewalks). Roof area may be excluded from this calculation.
Stormwater Runoff Calculation Criteria.
In addition to the infiltration and water quality requirements of this Part, peak flow from those activities resulting in increases in impervious surface and/or regrading and compaction shall be attenuated consistent with the following stormwater calculation methods:
The following design storms shall be used for analysis of the pre and post development conditions. These values are applicable to the soil-cover-complex method:
The precipitation values for each frequency storm listed above were abstracted from the precipitation frequency estimates developed by the National Oceanic and Atmospheric Administration as set forth in NOAA Atlas 14, Volume 2 (NOAA June 2004). The NOAA data are available from the Hydrometeorological Design Studies Center of the National Weather Service. The NOAA Atlas 14, volume two report can be accessed from the NOAA website at http://hdsc.nws.noaa.gov/hdsc/pfds/.
Wooded sites shall use a ground cover of woodland in good condition. Portions of a site having more than one viable tree of a DBH (Diameter at breast height (DBH) is the diameter of the tree stem 4 1/2 feet above the ground) of six inches or greater per 1,500 square feet shall be considered wooded where such trees existed within 10 years of application. If there is evidence of logging within the ten-year period logged area shall be consider as woodland in good condition.
All watershed area(s) contributing to the point of interest including off-site area shall be considered.
For redevelopment sites, see subsection .1.E.
The runoff curve numbers listed in the table below shall be used in developing the runoff calculations for the ground covers noted in subsection .2A(2)(a). These values are referenced from the Urban Hydrology for Small Watersheds Technical Release No. 55 (USDA, 1986). Coefficients for equivalent ground cover conditions shall be used if a runoff method other than the soil cover complex method is used.
Average antecedent moisture conditions, or AMC II, shall be used (for the soil cover complex method only for example, TR-55, TR-20).
For time of concentration calculations, sheet flow lengths shall not exceed 100 feet and shallow concentrated flow lengths shall not exceed 1,000 feet.
The kinematic "n" value in the sheet flow equation should be applied as per the following table. (Values taken from TR-55)
In all plans and designs for stormwater management systems and facilities submitted to the Township Engineer for approval, stormwater peak discharge and runoff shall be determined through the use of the NRCS Soil Cover Complex Method as set forth in Urban Hydrology for Small Watersheds, Technical Release No. 55 (USDA, 1986), with specific attention given to antecedent moisture conditions, flood routing, time of concentration, and peak discharge specifications included therein and in Hydrology National Engineering Handbook, section 4, (USDA, 1985) both by the U.S. Department of Agriculture, Natural Resources Conservation Service. Note that when TR-55 is used for natural system-based approaches and practices encouraged herein, calculations must be performed on a detailed small sub-area basis. Use of Technical Release No. 20 and other methods listed in Table 26-206-1 are also acceptable. The design professional's selection of a specific method shall be based on the suitability of the method for the given project site conditions with due consideration to the limitations of the method chosen. Table 26-206-1 herein summarizes the computational methods available.
Table 26-206-1
HEC — HMS
A modified rational method analysis may be used for drainage areas smaller than two acres when permitted by the Township Engineer. The term "modified rational method" used herein refers to a procedure for manipulation of the basic rational method techniques to reflect the fact that storms with a duration greater than the normal time of concentration for a basin will result in a larger volume of runoff even though the peak discharge is reduced. The methodology and model chosen for use shall be well documented as being appropriate for use in this region, and all relevant assumptions, methodologies, calculations and data used shall be provided to the Township Engineer for review. Information on the Modified Rational Method is presented in the Recommended Hydrologic Procedures for Computing Urban Runoff from Small Watersheds in Pennsylvania (PADEP, 1982).
Peak flow rate, cubic feet per second (CFS)
Runoff coefficient, dependent on land use/cover
Design rainfall intensity, inches per hour
Runoff characteristics of off-site areas that drain through a proposed development shall be considered and be based on the existing conditions in the off-site area.
Standards for Stormwater Management Practices. The Pennsylvania Stormwater Best Management Practices Manual shall serve as a guide for the design of stormwater management practices. Additional design guidance may also be obtained from other related sources, including the 2000 Maryland Stormwater Design Manual, Volumes I and II (MDE, 2000), Design of Stormwater Filtering Systems (CWP, 1996), and the American Society of Civil Engineers Manual and Report on Engineering Practice, No. 87, Urban Runoff Quality Management (ASCE, 1998) for the design of stormwater runoff quality control features for site development. A list of references is provided with this Part. The water quality volume design measures used herein are partially based on the methodology expressed in the Maryland manual referenced above.
Pursuant to the design options recommended in the above documents, the following standards shall be adhered to:
Extended Detention, Water Quality Volume, Infiltration and Nonstructural BMP Credits Criteria.
The following sizing criteria shall be followed at all sites required to meet the standards of this Part.
Detention ponds shall detain the one-year storm event and allow it to naturally infiltrate and recharge the groundwater table. All subsequent orifices for the two-, ten-, twenty-five-, and one-hundred-year storm events shall be placed above the maximum water surface elevation of the one-year storm.
Flow from off-site areas must be considered as pass-through flow if it is conveyed through the BMP and should be modeled as "present condition" for the one-year storm event.
The length of overland flow used in time of concentration (Tc) calculations is limited to no more than 100 feet for post development conditions.
Treatment of the water quality volume (WQv) of stormwater prior to its release to receiving waters or water bodies shall be provided at all developments where stormwater management is required. The WQv equals the storage volume needed to capture and treat the runoff from storms of one inch or less. Runoff from the first one inch of rainfall transports most of the total pollutant load.
Volumetric runoff coefficient, 0.05 + 0.009(I) where I is percent impervious cover.
The formula assumes approximately 5% runoff from pervious surfaces, and 90% runoff from impervious surfaces. A minimum of 0.2 inches per acre of runoff volume shall be met at sites or in drainage areas that have less than 15% impervious cover.
Stormwater Quality Treatment: The final WQv shall be treated by an acceptable stormwater management practice(s) from those described in this section or as approved by the Township.
For new developments, the WQv requirements of this section shall be sized and designed in conjunction with the standards under subsection .3.A(1)(b).
Multiple Drainage Areas: When a project contains or is divided by multiple drainage areas, the WQv volume shall be addressed for each drainage area.
Off-site Drainage Areas: The WQv shall be based on the impervious cover of the proposed site. Off-site existing impervious areas may be excluded from the calculation of the water quality volume requirements.
Infiltration Volume. Where possible, all of the water quality volume should be treated using infiltration BMPs. The following calculation shall be used to determine the minimum recharge goal for the site.
Rev = (S)(Ai) Where; S = soil specific recharge factor in inches
Ai = the-measured impervious cover
Infiltration should not be considered for sites or areas of sites that have activities that may allow pollution to be infiltrated. For example the use of infiltration for the runoff of a service stations paved lot would not be appropriate, although roof water from the service station may be infiltrated.
Infiltration should only be used when in the opinion of a professional engineer it will not contribute to slope instability or cause seepage problems into basements or developed down-gradient areas.
All infiltration facilities shall be set back at least 15 feet from all structures with sub-grade elements (e.g., basements, foundation walls).
Credits for Use of Nonstructural BMPs. The developer may obtain credits for the use of nonstructural BMPs using the procedures outlined below. Examples of nonstructural credit calculations are provided in Appendix 26-2-D.
A water quality volume reduction can be taken when undisturbed natural areas are conserved on a site, thereby retaining their pre-development hydrologic and water quality characteristics. Under this method, a designer would be able to subtract the conservation areas from the total site area when computing the water quality protection volume. An added benefit is that the post-development peak discharges will be smaller, and hence, water quantity control volumes will be reduced due to lower post-development curve numbers or rational formula "C" values.
Rule: Subtract conservation areas from total site area when computing water quality protection volume requirements.
Conservation area cannot be disturbed during project construction and must be protected from sediment deposition. The conservation area shall be protected with a safety fence until construction has been completed. After construction the area shall be posted with signage indicating that it is a conservation area.
Shall be protected by limits of disturbance clearly shown on all construction drawings.
Shall be located within an acceptable conservation easement instrument that ensures perpetual protection of the proposed area. The easement must clearly specify how the natural area vegetation shall be managed and boundaries will be marked [Note: managed turf (e.g., playgrounds, regularly maintained open areas) is not an acceptable form of vegetation management.]
Shall have a minimum contiguous area requirement of 10,000 square feet.
The minimum undisturbed buffer width shall be 50 feet from top of bank.
Not applicable if overland flow filtration/groundwater recharge reduction is already being taken.
Volume Reduction Method #3: Enhanced Swales.
This reduction may be taken when enhanced swales are used for water quality protection. Under the proposed method, a designer would be able to subtract the areas draining to an enhanced swale from total site area when computing water quality protection volume requirements. An enhanced swale can fully meet the water quality protection volume requirements for certain kinds of low-density residential development (see Volume Reduction Method #5). An added benefit is the post-development peak discharges will likely be lower due to a longer time of concentration for the site.
Rule: Subtract the areas draining to an enhanced swale from total site area when computing water quality protection volume requirements.
This method is typically only applicable to moderate or low density residential land uses (three dwelling units per acre maximum).
The maximum flow velocity for water quality design storm shall be less than or equal to 1.0 feet per second.
The bottom width shall be a maximum of six feet. If a larger channel is needed use of a compound cross section is required.
Volume Reduction Method #4: Overland Flow Filtration/Groundwater Recharge Zones.
This reduction can be taken when "overland flow filtration/infiltration zones" are incorporated into the site design to receive runoff from rooftops or other small impervious areas (e.g., driveways, small parking lots, etc.). This can be achieved by grading the site to promote overland vegetative filtering or by providing infiltration or "rain garden" areas. If impervious areas are adequately disconnected, they can be deducted from total site area when computing the water quality protection volume requirements. An added benefit will be that the post-development peak discharges will likely be lower due to a longer time of concentration for the site.
Rule: If impervious areas are adequately disconnected, they can be deducted from total site area when computing the water quality protection volume requirements.
Downspouts shall be at least 10 feet away from the nearest impervious surface to discourage "re-connections."
The length of the "disconnection" shall be equal to or greater than the contributing length.
The entire vegetative "disconnection" shall be on a slope less than or equal to 3%.
For those areas draining directly to a buffer, reduction can be obtained from either overland flow filtration -or-stream buffers (see Method #2).
Volume Reduction Method #5: Environmentally Sensitive Large Lot Subdivisions.
This reduction can be taken when a group of environmental site design techniques are applied to low and very low density residential development (e.g., 1 dwelling unit per two acres (du/ac) or lower). The use of this method can eliminate the need for structural storm water controls to treat water quality protection volume requirements. This method is targeted towards large lot subdivisions and will likely have limited application.
Rule: Targeted towards large lot subdivisions (e.g., two acre lots and greater). The requirement for structural facilities to treat the water quality protection volume may be waived.
Rooftop runoff is disconnected in accordance with the criteria in Method #4.
Lot areas should be at least two acres, unless clustering is implemented. Open space developments should have a minimum of 25% of the site protected as natural conservation areas and shall be at least a 1/2 acre average individual lot size.
Grass channels should be used to convey runoff versus curb and gutter (see Method #3).
Overland flow filtration/infiltration zones should be established (see Method #4).
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 and slope stability. The general process for designing the infiltration BMP shall be:
Soil characteristics, as subject to the specific considerations below:
Infiltration BMPs are particularly appropriate in hydrologic soil groups A and B, as described in the Natural Resources Conservation Manual TR-55.
The infiltration system shall have positive overflow controls to prevent storage within one-foot of the finished surface or grade.
Infiltration rates shall not be used the computing the storage volume of the infiltration system.
The recharge volume provided at the site shall be directed to the most permeable hydrologic soil group available, except where other considerations apply such as in limestone geology.
The Township may require additional analyses for stormwater management facilities proposed for susceptible areas such as:
Storage areas for salt, chloride, other materials for winter deicing.
During the period of land disturbance, runoff shall be controlled prior to entering any proposed infiltration area. Areas proposed for infiltration BMP's shall be protected from sedimentation and compaction during the construction phase, so as to maintain their maximum infiltration capacity.
Infiltration BMP's shall not be constructed nor receive runoff until the entire contributory drainage area to the infiltration BMP has received final stabilization.
All infiltration facilities that serve more than one lot and are considered a common facility shall have a drainage easement. The easement shall provide to the Township the right of access.
Soil evaluations shall be performed to determine the feasibility and extent to which infiltration systems can be used. The evaluation shall be performed by a qualified, licensed geologist, geotechnical/civil engineer or soil scientist and, at a minimum, address soil types, soil permeability, depth to bedrock, limitations of soils, presence/absence of carbonate geology susceptibility to subsidence and/or sinkhole formation and subgrade stability. The testing and evaluation should be completed at the preliminary design stage.
Soil infiltration tests shall be performed to an equivalent depth or elevation of the bottom of the proposed infiltration areas. These tests shall follow the procedures of percolation test holes as established by the ACHD for on-lot septic systems. The testing shall include a test pit and percolation test holes. The test hole shall be excavated to a depth so that the presence or absence of bedrock and/or seasonal high water table can be determined. A soil log describing the soils present in each test pit shall be performed. All test holes used for evaluating the percolation rate shall be pre-soaked in accordance with the procedures established by the ACHD. The location and number of test pits and percolation holes shall be determined based on the type(s) of stormwater management facilities being designed. Acceptability of infiltration rates shall be based on sound engineering judgment and recommended design considerations described in the design manuals listed in the references or other source material acceptable to the Township Engineer.
The lowest elevation of the infiltration area shall be at least two feet above the seasonal high water table and bedrock.
During site construction, all infiltration practice components shall be protected from compaction due to heavy equipment operation or storage of fill or construction material. Infiltration areas shall also be protected from sedimentation. Areas that are accidentally compacted or graded shall be remediated to restore soil composition and porosity. Adequate documentation to this effect shall be submitted for review by the Township Engineer. All areas designated for infiltration shall not receive runoff until the contributory drainage area has achieved final stabilization.
The tops and sides of all seepage beds, trenches, or like facilities shall be covered with drainage fabric. Fabric shall meet the specifications of PennDOT Publication 408, § 735, Construction Class one.
Open vegetated channels primarily serve a water quality function (WQv), they also have the potential to augment infiltration. Examples of such systems include, but are not limited to: dry swales, wet swales, grass channels, and biofilters. Open vegetated channels are primarily applicable for land uses such as roads, highways, residential developments (dry swales only) and pervious areas.
The peak velocity of the runoff from the ten-year storm shall be non-erosive for the soil and ground cover provided in the channel.
Accumulated sediment within the channel bottom shall be removed when 25% of the original WQv volume has been exceeded. The channel shall be provided with a permanent concrete cleanout marker that indicates the 25% loss level.
Retention basins shall be designed to create a healthy ecological community with sufficient circulation of water to prevent the growth of unwanted vegetation and mosquitoes or other vectors. If circulation cannot be provided via natural means, then artificial aeration and circulation shall be provided. Care shall be taken to landscape retention basins in accordance with subsection .4.
The retention basin shall be of sufficient size to allow the appropriate aquatic community needed to maintain healthy pond ecology and avoid mosquitoes capable of carrying West Nile Virus and other diseases. The ACHD, Pennsylvania Fish and Boat Commission, the Natural Resource Conservation Service, the Pennsylvania Extension Service, or other qualified professional consultant shall be consulted during the design of these facilities in order to ensure the health of aquatic communities and minimize the risk of creating mosquito breeding areas.
The design of a retention basin shall include the determination of the proposed site's ability to support a viable permanent pool. The design shall take into account such factors as the available and required rate and quality of dry weather inflow, the stormwater inflow, seasonal and longer-term variations in ground water table, and impacts of potential pollutant loadings.
A sediment forebay with a hardened bottom shall be provided at each inlet into the retention basin. The forebay storage capacity shall at minimum be 10% of the permanent pool storage. The forebay shall be designed to allow for access by maintenance equipment for periodic cleaning. A permanent concrete cleanout maker shall be installed in the forebay to indicate the level where 25% for the forebay storage has been used.
Emergency spillways shall be sized and located to permit the safe passage of stormwater flows from an unattenuated one-hundred-year post-development storm with one foot of freeboard. The maximum velocities in vegetated spillways excavated in otherwise undisturbed soil shall be analyzed based upon the velocity of peak flow in the emergency spillway during an assumed clogged primary outlet condition. Where maximum velocities exceed design standards contained in the Engineering Field Manual for Conservation Practices (USDA, SCS, July 1984) suitable lining shall be provided. All emergency spillways placed on fill materials shall be lined. Lining for emergency spillways shall incorporate native colors and materials where possible including mono slab revetments, grass pavers, rip rap and native stone.
Basin and pond embankments must be designed by a professional engineer registered in the Commonwealth of Pennsylvania. The design must include an investigation of the subsurface conditions at the proposed embankment location to evaluate settlement potential, groundwater impacts, and the need for seepage controls. The submittal of a geotechnical report from a geotechnical engineer for any embankment over 10 feet in effective height or posing a significant hazard to downstream property or life is required. The selection of fill materials must be subject to approval of the design engineer. Fill must be free of frozen soil, rocks over six inches, sod, brush, stumps, tree roots, wood, or other perishable materials. Embankment fills less than 10 feet in fill height must be compacted using compaction methods that would reasonably guarantee that the fill density is at least 90% of the maximum density as determined by standard proctor (ASTM-698). All embankment fills more than 10 feet in fill height must be compacted to at least 90% of the maximum density as determined by standard proctor (ASTM-698) and must have their density verified by field density testing. A PADEP dam permit is required for embankments having a maximum depth of water, measured from the upstream toe of the dam to the top of the dam at maximum storage elevation, of greater than 15 feet; and/or for ponds having contributory drainage area of greater than 100 acres; and or for impoundments of greater than 50 acre-feet.
The embankment's interior slope may not be steeper than three horizontal to one vertical. The exterior slope of the embankment may not exceed two horizontal to one vertical.
The minimum embankment width shall be four feet for embankments less than six feet in height, six feet if the embankment is between 6.1 feet and 9.9 feet in height and eight feet if the embankment is between 10 feet and 15 feet in height.
Fencing of the facility is not required if the interior slope of the pond is 4H:1V or flatter and the design also includes a five-foot wide bench around the pond perimeter at an elevation one foot below the permanent water surface elevation.
Stabilization. Proper stabilization structures, including stilling basins, energy dissipators, and channel lining shall be constructed at the outlets of all retention basins and emergency spillways. The stabilization structures shall control water to: avoid erosion; reduce velocities of released water and direct water so that it does not interfere with downstream activities.
Energy dissipators and/or level spreaders shall be installed to prevent erosion and/or initiate sheet flow at points where pipes or drainage ways discharge to or from basins. Level spreaders shall be used only where the maximum slope between the discharge point and the waterway does not exceed 5%. Energy dissipators shall comply with criteria in "Design of Energy Dissipators for Culverts and Channels," HEC 14, FHWA, July, 2006. Such facilities shall be both functional and harmonious with the surrounding environment; for example, native rock shall be used in constructing dissipators where practical.
Discharge Points. The minimum distance between a proposed basin discharge point (including the energy dissipator, etc.) and a downstream property boundary shall in no case be less than 15 feet. Where there is discharge onto or through adjacent properties prior to release to a stream, designers shall demonstrate how downstream properties are to be protected. The Township Engineer may require that the setback distance be increased based upon factors such as topography, soil conditions, the size of structures, the location of structures, and discharge rates. A drainage easement may also be required.
Basin outlet structures shall have childproof non-clogging trash racks over all design openings exceeding 12 inches in diameter except those openings designed to carry perennial stream flows. Periodic cleaning of debris from trash racks shall be included in the operation and maintenance plan.
The landscape standards of subsection .4 shall apply.
The maximum inside side slopes shall not exceed three horizontal to one vertical. The minimum required slope for the basin bottom is 2%. A level bottom is acceptable, provided the designer demonstrates to the Township's satisfaction that the basin bottom will be landscaped with appropriate wetland vegetation pursuant to subsection .4. In addition, detention basins of sufficient size and slope may serve other functions as well, including recreational uses which do not hinder or conflict with the function of the detention basin.
Low Flow Channels. Low flow channels constructed of concrete or asphalt are not permitted. Where low flow channels are necessary, they shall be composed of a natural or bioengineered material. Low flow channels shall be designed to promote water quality and slow the rate of flow through the basin. Low flow channels may also be designed to infiltrate where practical.
Basin outlet structures shall have childproof non-clogging trash racks over all design opening exceeding 12 inches in diameter except those openings designed to carry perennial stream flows.
Emergency spillways shall be sized and located to permit the safe passage of stormwater flows from an unattenuated one-hundred-year post-development storm with one-foot of freeboard. The maximum velocities in vegetated spillways excavated in otherwise undisturbed soil shall be analyzed based upon the velocity of peak flow in the emergency spillway during an assumed clogged primary outlet condition. Where maximum velocities exceed design standards contained in the Engineering Field Manual for Conservation Practices (USDA, SCS, July 1984) suitable lining shall be provided. In general, emergency spillways should not be located in fill areas; all such facilities placed on fill materials shall be lined. Lining for emergency spillways shall incorporate native colors and materials where possible, including mono slab revetments, grass pavers, rip rap and native stone.
Basin and pond embankments must be designed by an engineer. The design must include an investigation of the subsurface conditions at the proposed embankment location to evaluate settlement potential, groundwater impacts, and the need for seepage controls. The submittal of a geotechnical report from a geotechnical engineer for any embankment over 10 feet in effective height or posing a significant hazard to downstream property or life is required. The selection of fill materials must be subject to approval of the design engineer. Fill must be free of frozen soil, rocks over six inches, sod, brush, stumps, tree roots, wood, or other perishable materials. Embankment fills less than 10 feet in fill height must be compacted using compaction methods that would reasonably guarantee that the fill density is at least 90% of the maximum density as determined by standard proctor (ASTM-698). All embankment fills more than 10 feet in fill height must be compacted to at least 90% of the maximum density as determined by standard proctor (ASTM-698) and must have their density verified by field density testing. A PADEP dam permit is required for embankments having; a maximum depth of water, measured from the upstream toe of the dam to the top of the dam at maximum storage elevation, of greater than 15 feet; and or for ponds having contributory drainage area of greater than 100 acres; and or for impoundments of greater than 50 acre-feet.
The embankment's interior slope may not be steeper than 3:1 (three horizontal to one vertical). The exterior slope of the embankment may not exceed 2:1 (two horizontal to one vertical).
Freeboard. Freeboard is the difference between the elevation of the design flow in the emergency spillway (usually the one-hundred-year peak elevation) and the top elevation of the settled basin embankment (that is, top of berm). The minimum freeboard shall be one-foot.
Energy dissipators and/or level spreaders shall be installed to prevent erosion and/or initiate sheet flow at points where pipes or drainage ways discharge to or from basins. Level spreaders shall be used only where the maximum slope between the discharge point and the waterway does not exceed 5%. Energy dissipators shall comply with criteria in "Hydraulic Design of Energy Dissipators for Culverts and Channels," HEC 14, FHWA, July, 2006. Such facilities shall be both functional and attractive; for example, native rock shall be used in constructing dissipators where practical.
Wherever conveyance channels are necessary, drainage shall be maintained by an open channel with landscaped banks designed to carry the ten-year, twenty-four-hour stormwater runoff from upstream contributory areas. The Township Engineer may increase the design storm, as conditions require. All open channels shall be designed with one-foot of freeboard above the design water surface elevation of the design runoff condition.
Where drainage swales are used in lieu of or in addition to storm sewers, they shall be designed to carry the required runoff without erosion and in a manner not detrimental to the properties they cross. Drainage swales shall provide a minimum grade of 2% but shall not exceed a grade of 9%. Drainage swales used strictly for conveyance are not the same as open vegetated channels. Design standards for open vegetated channels are provided under subsection .3.C of this Part.
All storm sewers, drainage swales, channels, permanent detention/retention basins and/or other stormwater management facilities providing stormwater control for other than a single lot shall be located within a defined drainage easement that allows proper legal access and maintenance vehicle access. This drainage easement shall be a minimum of 20 feet wide.
Water Quality Inlets. Storm drainage systems that collect runoff from parking areas and/or loading areas exceeding 10,000 square feet of impervious coverage and discharge to stormwater management systems, including surface or subsurface infiltration systems, shall have a minimum of one water quality inlet per each acre of drainage area. The purpose of water quality inlets is to remove oil, grease, and heavy particulates or total suspended solids, hydrocarbons and other floating substances from stormwater runoff. Methods other than water quality inlets may be permitted if the applicant demonstrates to the Township's satisfaction that any such alternative will be as effective and as easily maintained. Periodic cleaning of these systems shall be addressed in the operation and maintenance plan submitted to the Township.
Landscaping of Stormwater Management Facilities. Stormwater management facilities shall be landscaped in accordance with the following standards:
Stabilizing the soil within such facilities to minimize and control erosion.
Enhancing the visual appearance of such facilities.
Wet meadows including floors of stormwater management facilities.
Wet meadows and floors of stormwater management facilities shall be planted with non-invasive plants native to western Pennsylvania such as wildflowers and non-invasive grasses, the intent being to create a mixed meadow of such plantings, where appropriate. Selection of plantings shall be based on whether the area in question is usually well drained or permanently wet and whether the area will be used for recreation purposes. No woody plants shall be planted within the saturated zone (phreatic line) of a stormwater management practice or on a berm constructed for impounded water.
Seeding shall take place either between April 1 and May 15 or between September 1 and October 15. Planting areas shall be soaked to maintain a consistent level of moisture for at least four to six weeks after planting. For seeding recommendations, reference the DEP's E&S Pollution Control Program Manual.
On steep slopes as defined by the Zoning Ordinance [Chapter 27], dense spreading shrubs (shrubs tolerant of dry soils) shall be planted. Heavy mat mulch shall be used during the period of establishment.
Stream Buffer Requirements. Stream buffers shall be provided for new development sites as per the following requirements:
Stream buffer averaging shall be applied to each side of a stream independently. If the property being developed encompasses both sides of a stream, buffer averaging can be applied to both sides of the stream, but must be applied to both sides of the stream independently.
The owner of stormwater management facilities, as defined and/or set forth in the operation and maintenance agreement referenced in subsection .4, shall be responsible for the proper operation and maintenance of those facilities during and after construction. An operation and maintenance plan consistent with the requirements of subsection .3 shall be prepared for review and approval by the Township Engineer and shall be executed and signed by the Township Engineer and applicant.
The owner of the stormwater management facilities, as defined and/or set forth in the operation and maintenance agreement referenced in subsection .4, shall be responsible for the proper installation and function of those facilities in accordance with the approved stormwater management plan. All temporary soil erosion and sedimentation control measures shall be removed or converted to their permanent configuration in accordance with an approved erosion and sedimentation control plan. This requirement in no way precludes the authority of the ACCD to determine when sufficient stabilization has occurred on a site in order to convert to the permanent stormwater management facilities.
Dedication and Acceptance of Stormwater Management Facilities.
After completion of construction of stormwater management facilities shown on an approved subdivision and/or land development plan, the applicant may submit a written offer of such stormwater management facilities for dedication to the Township or other authorized public entity. Said offer shall include a deed of dedication covering said facilities together with satisfactory proof establishing an applicant's clear title to said property. Such documents are to be filed with the Township Secretary for review by the Township Solicitor. Deeds of dedication for stormwater management facilities may be accepted by resolution of the Township, at the Township's sole discretion, but the Township is under no obligation to accept an offer of dedication.
The Township may require that stormwater management facilities remain undedicated, with operation and maintenance the responsibility of individual lot owners or a homeowners association or similar entity, or an organization capable of carrying out maintenance responsibilities.
Regardless of ownership, the applicant shall submit an actual "as built" plan to the Township for the stormwater management facilities required by the approved stormwater management plan. The "as built" plan shall show all final design specifications for all permanent stormwater management facilities including, but not limited to, pipe material and diameter, inlet, outlet and overflow elevations, two-foot contours for all detention/retention basins and drainage swales and a comparison of "as-built" capacities compared to the capacities of the approved design facilities and shall be prepared and certified by an engineer. The "as built" plan shall be based on an actual field survey performed by a professional land surveyor licensed as such by the Commonwealth of Pennsylvania. The surveyor shall certify as to the accuracy of the plan. The "as built" plan shall be submitted to the Township for review and approval by the Township Engineer. The "as-built" plan(s) shall be submitted to the Township in a digital format or formats approved by the Township.
Ownership and Maintenance. All stormwater management facilities identified within an approved stormwater management plan shall be owned and maintained by one, or a combination of, the following entities:
Where individual on-lot stormwater management facilities are proposed, the subdivision and/or land development plan shall contain a note in a form acceptable to the Township Solicitor designating the entity responsible for operation and maintenance of the on-lot facilities consistent with an approved operation and maintenance plan and, in the event that the responsible person or entity fails to do so, granting to the Township the right but not the duty to enter upon the premises to repair or restore said facilities, to charge and assess the costs thereof to the owner, including reasonable attorneys fees, and to enforce said charges and assessments by lien upon the property. In addition, the deed for each lot shall contain a perpetual covenant binding the grantee and all successors in interest designating the responsibility for operation and maintenance of the on-lot facilities essentially in the following form and otherwise acceptable to the Township Solicitor:
"UNDER AND SUBJECT, to the following conditions and restrictions: Prior to any Earth Disturbance for which stormwater management facilities are required by the Township, Grantee shall construct the permanent stormwater management facilities as shown on the stormwater management plan (the "Plan") prepared by <NAME>, P.E., dated <DATE> and last revised <DATE> and approved by the Township; thereafter, the Grantee, his heirs, executors, administrators, successors and assigns ("Owner"), at his sole cost and expense, shall operate, maintain and repair said stormwater management facilities on the lot in accordance with said Plan, so that the facilities shall at all times continue to operate and function in the same manner and capacity as they were designed. In the event of the failure of the Owner to comply with these conditions and restrictions, the Township may have said stormwater management facilities repaired or restored as required, and any costs thereof, including reasonable attorneys fees, shall be assessed to the Owner; said assessment shall be a charge and a continuing lien upon the property herein."
In addition to the above, developers of parcels with more than one dwelling unit shall record with the Allegheny County Department of Real Estate a declaration of covenants and restrictions in a form satisfactory to the Township Solicitor describing the responsibility for operation and maintenance of the on-lot facilities, consistent with an approved operation and maintenance plan, prior to the sale of any individual lots. The terms of this covenant and restriction shall run with the land and be binding upon the grantees of each lot within the subdivision, his, her or their heirs, administrators, successors or assigns.
Homeowners or Condominium Association Ownership. Where a homeowners association or condominium association (collectively, the "association") is created to own and manage common facilities, the subdivision and/or land development plan shall contain a note in a form satisfactory to the Township Solicitor designating the entity responsible for construction and/or maintenance of the stormwater management facilities consistent with an approved operation and maintenance plan and, in the event that the responsible entity fails to do so, granting to the Township the right but not the duty to enter upon the premises to repair or restore said facilities, to charge and assess the costs thereof, plus reasonable attorneys fees, to each owner of property within the development and to enforce said charges and assessments by lien upon each property within the development. In addition, the developer shall record with the Allegheny County Department of Real Estate a declaration of covenants in a form satisfactory to the Township Solicitor setting forth the rights and responsibilities of the association for operation and maintenance of the stormwater management facilities, prior to the sale of individual lots. The terms of this covenant and restriction shall run with the land and be binding upon the grantees of each lot within the subdivision, his, her or their heirs, administrators, successors and assigns.
Public Entity Ownership.
Where the Township or other authorized public entity has accepted an offer of dedication of the permanent stormwater management facilities, said public entity shall be responsible for operation and maintenance of the stormwater maintenance facilities. Public entity ownership notwithstanding, the applicant is required to prepare a stormwater management plan and an operation and maintenance plan, as defined herein. Upon approval of the stormwater management facilities by the Township, the applicant shall provide a lump sum long-term maintenance payment to the Township, to be reserved and used at any time by the Township only for costs of operation and maintenance of the dedicated facilities, as follows:
Long-Term Maintenance Payment. The long-term maintenance payment shall be in an amount equal to the present value of operation and maintenance costs for the facilities for a ten-year period. The long-term maintenance payment shall be based on a ten-year cost estimate prepared by the applicant's engineer and reviewed and approved by the Township Engineer. The amount of the payment shall include all costs of operation and maintenance which shall include but not be limited to, typical operation and maintenance costs as well as costs such as landscaping and planting, and construction of any kind associated with the use, benefit and enjoyment of the facilities by the owners. In particular, a description of routine facility operation and day-to-day management requirements and a description of projected maintenance actions and schedules necessary to ensure proper operation of stormwater management facilities shall be submitted for review and approval to the Township Engineer.
Documentation. The terms of the long-term maintenance payment shall be documented as part of the stormwater management plan and the operation and maintenance plan.
Operation and Maintenance Plan. An operation and maintenance plan shall be prepared by an engineer which identifies the ownership, operation and maintenance responsibilities and as-built conditions for all stormwater management facilities. Security for such operation and maintenance shall be established in the operation and maintenance agreement referenced in subsection .4.A. At a minimum, the operation and maintenance plan shall include the following:
Any obligations concerning perpetuation and/or maintenance of natural drainage or infiltration facilities, and other facilities identified within the stormwater management plan. Ownership of and responsibility for operation and maintenance of stormwater management facilities, including names and contact information, shall be required.
A description of the permanent stormwater management facilities on the site, explaining how each facility is intended to function and operate over time. All drainage and access easements shall be depicted and any site restrictions to be recorded against the property shall be identified on the recorded plan. All such easements and restrictions shall be perfected to run with the land and be binding upon the landowner and any successors in interest.
A description of the actions, budget and schedule for operating and maintaining the stormwater management facilities. This description should be written in a clear manner, consistent with the knowledge and understanding of the intended user.
A general description of operation and maintenance activities and responsibilities for facilities held in common or on-lot including, but not limited to, lawn care, vegetation maintenance, clean out of accumulated debris and sediment (including from grates, trash racks, inlets, etc.), liability insurance, maintenance and repair of stormwater management facilities, landscaping and planting, payment of taxes and construction of any kind associated with the use, benefit and enjoyment of the facilities by the owners. In particular, a description of routine facility operation and day-to-day management requirements (as needed) and a description of routine maintenance actions and schedules necessary to ensure proper operation of stormwater management facilities shall be submitted.
Assurances that no action will be taken by any lot owner to disrupt or in any way impair the effectiveness of any stormwater management system, setting forth in deed restrictions the ability of the Township to take corrective measures if it is determined at any time that stipulated permanent stormwater management facilities have been eliminated, altered, or improperly maintained, including the ability of the Township to cause the work to be done and lien all costs including reasonable attorneys fees against the property should the required corrective measures not be taken by the lot owner, following written notification, within a period of time set by Township Engineer.
Parties responsible for the long term operation and maintenance of stormwater management facilities shall make records of the installation and of all maintenance and repairs, and shall retain the records for at least 10 years. These records shall be submitted to the Township as established by the operation and maintenance plan or as otherwise required by the Township.
Operations and Maintenance Agreement.
Prior to a developer and/or landowner commencing grading or construction activities related to the stormwater management plan, the developer and/or landowner shall execute an operations and maintenance agreement, in a form acceptable to the Township Solicitor, containing provisions to guarantee and secure the proper operation and maintenance of the stormwater management facilities. This operation and maintenance agreement may be referred to as the stormwater management agreement. A standard form of this operation and maintenance agreement may be adopted from time to time by resolution of the Township Board of Supervisors.
The owner of any land upon which permanent stormwater management facilities and/or BMPs will be placed, constructed or implemented, as described in an approved stormwater management plan and the operations and maintenance plan, shall record the following documents in the Office of the Recorder of Deeds for Allegheny County, within 15 days of approval of the operations and maintenance plan by the Township:
Operation and maintenance agreement referenced in subsection. 4.A above.
Access and/or drainage easements.
The Township may suspend or revoke any approvals panted for the project site upon discovery of the failure of the owner to comply with subsection .4.A or the operation and maintenance agreement referenced in subsection .4.A of this Part.
Plan Submission. The Township shall require receipt of a complete plan, as specified in this Part.
Six copies of the stormwater management plan shall be submitted and distributed as follows:
Two copies to the Township accompanied by the requisite application fee and deposit pursuant to subsection .5.
Two copies to the ACCD.
One copy to the Allegheny County Planning Agency.
The Township Engineer shall review the stormwater management plan for consistency with this Part. Any stormwater management plan found incomplete shall not be accepted for review and shall be returned to the applicant.
The Township Engineer shall review the stormwater management plan for any subdivision or land development against the provisions of the Subdivision and Land Development Ordinance [Chapter 22] not superseded by this Part.
When required by regulation, the ACCD shall review and approve the erosion and sedimentation control plan for consistency with PADEP's regulations.
For activities regulated by this Part, the Township Engineer shall notify the applicant and the Township, whether the stormwater management plan is consistent with this Part.
Should the stormwater management plan be determined to be consistent with this Part, the Township Engineer shall forward an approval letter to the Township Secretary who will then forward a copy to the applicant.
Should the stormwater management plan be determined to be inconsistent with this Part, the Township Engineer shall forward a denial letter to the Township Secretary who will then forward a copy to the applicant. The denial letter shall cite the reason(s) and specific sections of this Part for the denial. Denial may be due to inadequate information to make a reasonable judgment as to compliance with the requirements of this Part. Any denied stormwater management plans may be revised by the applicant and resubmitted consistent with this Part.
For regulated activities specified in § 26-204 of this Part which require a building permit, the Township Engineer shall notify the Township Building Code Official in writing, within a time frame consistent with Chapter 5, Part 1 of the Frazer Township Code of Ordinances, Construction Code, as amended, whether the stormwater management plan is consistent with this Part and forward a copy of the approval/denial letter to the applicant. Any denied stormwater management plan may be revised by the applicant and resubmitted consistent with this Part.
For regulated activities under this Part that require an NPDES permit application, the applicant shall forward a copy of the Township Engineer's letter stating that the stormwater management plan is consistent with this Part to the ACCD, PADEP and the ACCD may consider the Township Engineer's review comments in determining whether to issue a permit.
No building permits shall be issued for any regulated activity specified in § 26-204 of this Part if the stormwater management plan has been found to be inconsistent with this Part, as determined by the Township Engineer, or without considering the comments of the Township Engineer. All required permits from PADEP must be obtained prior to issuance of a building permit.
The applicant shall be responsible for completing record drawings of all stormwater management facilities included in the approved stormwater management plan. The record drawings and an explanation of any discrepancies with the design plans shall be submitted to the Township Engineer for final approval. In no case shall the Township approve the record drawings until the Township receives a copy of an approved PennDOT highway occupancy permit, NPDES permit, and any other applicable permits or approvals, including such permits and approvals from PADEP or the ACCD. The above permits and approvals must be based on the record drawings. The record drawings must include copies of all applicable permits and approvals.
The Township's approval of a stormwater management plan shall be valid for a period not to exceed five years commencing on the date that the Township approves the stormwater management plan. If stormwater management facilities included in the approved stormwater management plan have not been constructed, or if constructed and record drawings of these facilities have not been approved within this time period, then the Township may consider the stormwater management plan denied and may revoke any and all permits. Stormwater management plans that are considered denied by the Township shall be resubmitted in accordance with Subsection 4 of this section.
Modification of Plans. A modification to a stormwater management plan under review by the Township for a development site that involves a change in stormwater management facilities or techniques, or that involves the relocation or re-design of stormwater management facilities, or that is necessary because soil or other conditions are not as stated on the stormwater management plan as determined by the Township Engineer, shall require a resubmission of a modified stormwater management plan consistent with this Part and shall be subject to review under this Part.
Resubmission of Disapproved Stormwater Plans. A denied stormwater management plan may be resubmitted, provided that it includes revisions addressing the grounds for denial and the Township Engineer's concerns in the written denial letter referenced under Subsection 5 of this section. Any such resubmittal shall be subject to review as specified in this section of this Part. The applicable Township application fee and deposit pursuant to subsection .2 must accompany a resubmission of a denied stormwater management plan.
Application Fees and Deposits. The Township Board of Supervisors shall establish, from time to time by resolution, application fees and deposits to be paid by the applicant/developer at the time of filing the relevant application under this Part.
Review Fees and Expenses. The applicant/developer shall reimburse the Township for all fees and expenses incurred by the Township related to a stormwater management plan and/or the review of any application under this Part, including but not limited to the reasonable and necessary charges by the Township Engineer and/or Township Solicitor for review and report on an application and/or stormwater management plan under this Part and the inspection of improvements related thereto.