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Notwithstanding any provision(s) of this chapter, including exemptions, any landowner or any person engaged in the alteration or development of land which may affect stormwater runoff characteristics shall implement such measures as are reasonably necessary to prevent injury to health, safety or other property. Such measures also shall include actions as are required to manage the rate, volume, direction and quality of resulting stormwater runoff in a manner which otherwise adequately protects health, property and water quality.
(Ord. 1508, passed 12-20-2010)
(A) Neither the granting of any approval under this chapter, nor the compliance with the provisions of this chapter, or with any condition imposed by a municipal official hereunder, shall relieve any person from any responsibility for damage to persons or property resulting therefrom, or as otherwise imposed by law nor impose any liability upon the municipality for damages to persons or property.
(B) The granting of a permit which includes any stormwater management facilities shall not constitute a representation, guarantee or warranty of any kind by the municipality, or by an official or employee thereof, of the practicability or safety of any structure, use or other plan proposed, and shall create no liability upon or cause of action against such public body, official or employee for any damage that may result pursuant thereto.
(Ord. 1508, passed 12-20-2010)
(A) For the purpose of this chapter, certain terms and words used herein shall be interpreted as follows.
(1) Words used in the present tense include the future tense; the singular number includes the plural; and the plural number includes the singular; words of masculine gender include feminine gender; and words of feminine gender include masculine gender.
(2) The word INCLUDES or INCLUDING shall not limit the term to the specific example but is intended to extend its meaning to all other instances of like kind and character.
(3) The word PERSON includes an individual, firm, association, organization, partnership, trust, company, corporation or any other similar entity.
(4) The words SHALL and MUST are mandatory; the words MAY and SHOULD are permissive.
(5) The words USED OR OCCUPIED include the words “intended, designed, maintained or arranged to be used, occupied or maintained”.
(B) For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
ACCELERATED EROSION. The removal of the surface of the land through the combined action of human activity and natural processes at a rate greater than would occur because of the natural process alone.
AGRICULTURAL ACTIVITIES. Activities associated with agriculture, such as agricultural cultivation, agricultural operation and animal heavy use areas. This includes the work of producing crops, tillage, land clearing, plowing, disking, harrowing, planting, harvesting crops or pasturing and raising of livestock and installation of conservation measures. Construction of new buildings or impervious area is not considered an AGRICULTURAL ACTIVITY.
ALTERATION. As applied to land, a change in topography as a result of the moving of soil and rock from one location or position to another; changing of surface conditions by causing the surface to be more or less impervious; land disturbance.
APPLICANT. A landowner, developer or other person who has filed an application for approval to engage in any regulated activities at a project site within the municipality.
BEST MANAGEMENT PRACTICES (BMPS). Activities, facilities, designs, measures or procedures used to manage stormwater impacts from regulated activities, to meet state water quality requirements, to promote groundwater recharge and to otherwise meet the purposes of this chapter. STORMWATER BMPs are commonly grouped into one of two broad categories or measures: “non-structural” or “structural”. NON-STRUCTURAL BMPs are measures referred to as operational and/or behavior-related practices that attempt to minimize the contact of pollutants with stormwater runoff, whereas STRUCTURAL BMPs are measures that consist of a physical device or practice that is installed to capture and treat stormwater runoff. STRUCTURAL BMPs include, but are not limited to, a wide variety of practices and devices, from large-scale retention ponds and constructed wetlands, to small-scale underground treatment systems, infiltration facilities, filter strips, low impact design, bioretention, wet ponds, permeable paving, grassed swales, riparian or forested buffers, sand filters, detention basins, and manufactured devices. STRUCTURAL STORMWATER BMPs are permanent appurtenances to the project site.
CHANNEL EROSION. The widening, deepening and headword cutting of small channels and waterways, due to erosion caused by moderate to large floods.
CISTERN. An underground reservoir or tank used for storing rainwater.
CONSERVATION DISTRICT. The Erie County Conservation District. The Erie County Conservation District has the authority under a delegation agreement executed with the Department of Environmental Protection to administer and enforce all or a portion of the regulations promulgated under 25 Pa. Code Chapter 102.
CULVERT. A structure with appurtenant works that carries a stream and/or stormwater runoff under or through an embankment or fill.
DAM. An artificial barrier, together with its appurtenant works, constructed for the purpose of impounding or storing water or another fluid or semifluid, or a refuse bank, fill or structure for highway, railroad or other purposes which does or may impound water or another fluid or semifluid.
DESIGN STORM. The magnitude and temporal distribution of precipitation from a storm event measured in probability of occurrence (e.g., a 25-year storm) and duration (e.g., 24-hours), used in the design and evaluation of stormwater management systems. Also see RETURN PERIOD.
DESIGNEE. The agent of this municipality and/or agent of the governing body involved with the administration, review or enforcement of any provisions of this chapter by contract or memorandum of understanding.
DETENTION BASIN. An impoundment structure designed to manage stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate.
DETENTION VOLUME. The volume of runoff that is captured and released into waters of the state at a controlled rate.
DEVELOPER. A person, partnership, association, corporation or other entity, or any responsible person therein or agent thereof, that undertakes any regulated activity of this chapter.
DEVELOPMENT SITE (SITE). The specific tract of land for which a regulated activity is proposed. Also see PROJECT SITE.
DISTURBED AREA. An unstabilized land area where an earth disturbance activity is occurring or has occurred.
DOWNSLOPE PROPERTY LINE. The portion of the property line of the lot, tract or parcels of land being developed located such that all overland or pipe flow from the site would be directed toward it.
DRAINAGE CONVEYANCE FACILITY. A stormwater management facility designed to convey stormwater runoff and shall include streams, channels, swales, pipes, conduits, culverts, storm sewers and the like.
DRAINAGE EASEMENT. A right granted by a landowner to a grantee, allowing the use of private land for stormwater management, drainage or conveyance purposes.
DRAINAGEWAY. Any natural or artificial watercourse, trench, ditch, pipe, swale, channel or similar depression into which surface water flows.
EARTH DISTURBANCE ACTIVITY. A construction or other human activity which disturbs the surface of the land, including, but not limited to, clearing and grubbing, grading, excavations, embankments, land development, agricultural plowing or filling, timber harvesting activities, road maintenance activities, mineral extraction and the moving, depositing, stockpiling or storing of soil, rock or earth materials.
EROSION. The movement of soil particles by the action of water, wind, ice or other natural forces.
EROSION AND SEDIMENT POLLUTION CONTROL PLAN. A plan which is designed to minimize accelerated erosion and sedimentation.
EXCEPTIONAL VALUE WATERS. Surface waters of high quality, which satisfies Pa. Code Title 25 Environmental Protection, Chapter 93 Water Quality Standards 93.4b(b) (relating to anti- degradation).
EXISTING CONDITIONS. The initial condition of a project site prior to the proposed construction. If the initial condition of the site is undeveloped land and not forested, the land use shall be considered as “meadow” unless the natural land cover is documented to generate lower curve numbers or rational “C” coefficient.
FEMA. The Federal Emergency Management Agency.
FLOOD. A general but temporary condition of partial or complete inundation of normally dry land areas from the overflow of streams, rivers and other waters of the state.
FLOOD FRINGE. The remaining portions of the 100-year floodplain outside of the floodway boundary.
FLOODPLAIN. Any land area susceptible to inundation by water from any natural source or delineated by applicable Department of Housing and Urban Development, Federal Insurance Administration Flood Hazard Boundary mapped as being a special flood hazard area. Included are lands adjoining a river or stream that have been or may be inundated by a 100-year flood. Also included are areas that comprise Group 13 Soils, as listed in Appendix A of the Pennsylvania Department of Environmental Protection (PADEP) Technical Manual for Sewage Enforcement Officers (as amended or replaced from time to time by PADEP).
FLOODWAY. The channel of the watercourse and those portions of the adjoining floodplains that are reasonably required to carry and discharge the 100-year frequency 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 100-year frequency floodway, it is assumed, absent evidence to the contrary, that the FLOODWAY extends from the stream to 50 feet landward from the top of the bank of the stream.
FOREST MANAGEMENT/TIMBER OPERATIONS. Planning and activities necessary for the management of forest land. These include timber inventory and preparation of forest management plans, silvicultural treatment cutting budgets, logging road design and construction, timber harvesting, site preparation and reforestation.
FREEBOARD. A vertical distance between the elevation of the design high water and the top of a dam, levee, tank, basin or diversion ridge. The space is required as a safety margin in a tank, pond or basin.
GRADE. A slope, usually of a road, channel or natural ground specified in percent and shown on plans as specified herein.
(TO) GRADE. To finish the surface of a roadbed, top of embankment or bottom of excavation.
GROUNDWATER RECHARGE. Replenishment of existing natural underground water supplies.
HEC-HMS MODEL CALIBRATED (HYDROLOGIC ENGINEERING CENTER HYDROLOGIC MODELING SYSTEM). A computer-based hydrologic modeling technique adapted to the watershed(s) in the county for the Stormwater Management Act, being 32 P.S. §§ 680.1 et seq. The MODEL has been calibrated by adjusting key model input parameters.
HIGH QUALITY WATERS. Surface water having quality, which exceeds levels necessary to support propagation of fish, shellfish and wildlife and recreation in and on the wafer by satisfying Pa. Code Title 25 Environmental Protection, Chapter 93 Water Qualify Standards 93.4b(a).
HYDROLOGIC SOIL GROUP (HSG). Infiltration rates of soils vary widely and are affected by subsurface permeability as well as surface intake rates. Soils are classified into one of four HSG (A, B, C and D) according to their minimum infiltration rate, which is obtained for bare soil after prolonged wetting. The Natural Resource Conservation Service (NRCS) of the U.S. Department of Agriculture defines the four groups and provides a list of most of the soils in the United States and their group classification. The soils in the area of interest may be identified from a soil survey report from the local NRCS office or the County Conservation District.
IMPERVIOUS SURFACE (IMPERVIOUS AREA). A surface that prevents the infiltration of water into the ground, impervious surface (or areas) include, but is not limited to: roofs; additional indoor living spaces; patios; garages; storage sheds and similar structures; parking or driveway areas; and any new streets and sidewalks. Any surface areas proposed to initially be gravel or crushed stone shall be assumed to be IMPERVIOUS SURFACES.
IMPOUNDMENT. A retention or detention basin designed to retain stormwater runoff and release it at a controlled rate.
INFILTRATION STRUCTURES. A structure designed to direct runoff into the ground (e.g., french drains, seepage pits, seepage trench and the like).
INLET. A surface connection to a closed drain. A structure at the diversion end of a conduit. The upstream end of any structure through which water may flow.
LAND DEVELOPMENT (DEVELOPMENT).
(a) The improvement of one lot or two or more contiguous lots, tracts or parcels of land for any purpose involving:
1. A group of two or more buildings; or
2. The division or allocation of land or space between or among two or more existing or prospective occupants by means of, or for the purpose of, streets, common areas, leaseholds, condominiums, building groups or other features.
(b) Any subdivision of land; or
(c) Development in accordance with 53 P.S. § 503(1.1) of the Pa. Municipalities Planning Code.
LOW IMPACT DEVELOPMENT (LID). An approach to land development that uses various land planning and design practices and technologies to simultaneously conserve and protect natural resource systems and reduce infrastructure costs. LID still allows land to be developed, but in a cost-effective manner that helps mitigate potential environmental impacts.
MAIN STEM (MAIN CHANNEL). Any stream segment or other runoff conveyance facility used as a reach in the Stormwater Management Act, being 32 P.S. §§ 680.1 et seq., watershed hydrologic model(s).
MANNING EQUATION (MANNING FORMULA). A method for calculation of velocity of flow (e.g., feet per second) and flow rate (e.g., cubic feet per second) in open channels based upon channel shape, roughness, depth of flow and slope. “Open channels” may include closed conduits so long as the flow is not under pressure.
MUNICIPALITY. The City of Corry, Erie County, Pennsylvania.
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES). The federal government’s system for issuance of permits under the Clean Water Act, which is delegated to PADEP in the state.
NOAA ATLAS 14. Precipitation-Frequency Atlas of the United States, Atlas 14, Volume 2, U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Weather Service, Hydrometeorological Design Studies Center, Silver Spring, Maryland (2004). NOAA’S ATLAS 14 can be accessed at Internet address http://hdsc.nws.noaa.gov/hdsc/pfds/.
NON-POINT SOURCE POLLUTION. Pollution that enters a water body from diffuse origins in the watershed and does not result from discernible, confined or discrete conveyances.
NRCS. Natural Resource Conservation Service (previously Soil Conservation Service (SCS)).
OPEN CHANNEL. A drainage element in which stormwater flows with an open surface. OPEN CHANNELS include, but shall not be limited to, natural and human-made drainageways, swales, streams, ditches, canals and pipes not under pressure.
OUTFALL.
(a) Point where water flows from a conduit, stream or drain;
(b) “Point source” as described in 40 C.F.R. § 122.2 at the point where the municipality’s storm sewer system discharges to surface waters of the state.
OUTLET. Points of water disposal from a stream, river, lake, tidewater or artificial drain.
PADEP. The Pennsylvania Department of Environmental Protection.
PARKING LOT STORAGE. Involves the use of impervious parking areas as temporary impoundments with controlled release rates during rainstorms.
PEAK DISCHARGE. The maximum rate of stormwater runoff from a specific storm event.
PERSON. An individual, partnership, public or private association or corporation, firm, trust, estate, municipality, governmental unit, public utility or any other legal entity whatsoever which is recognized by law as the subject of rights and duties. Whenever used in any section prescribing or imposing a penalty, the term PERSON shall include the members of a partnership, the officers, members, servants and agents of an association, officers, agents and servants of a corporation, and the officers of a municipality or country, but shall exclude any department, board, bureau or agency of the state.
PERVIOUS AREA. Any area not defined as impervious.
PIPE. A culvert, closed conduit or similar structure (including appurtenances) that conveys stormwater.
PLANNING COMMISSION. The Planning Commission of the City of Corry.
POINT SOURCE. Any discernible, confined or discrete conveyance, including, but not limited to: any pipe; ditch; channel; tunnel; or conduit from which stormwater is or may be discharged, as defined in state regulations at 25 Pa. Code § 92a.1.
PROBABLE MAXIMUM FLOOD (PMF). The flood that may be expected from the most severe combination of critical meteorological and hydrologic conditions that are reasonably possible in any area. The PMF is derived from the probable maximum precipitation (PMP) as determined on the basis of data obtained from the National Oceanographic and Atmospheric Administration (NOAA).
PROJECT SITE. The specific area of land where any regulated activities in the municipality are planned, conducted or maintained.
QUALIFIED PROFESSIONAL. Any person licensed by the Pennsylvania Department of State or otherwise qualified by law to perform the work required by the chapter.
RATIONAL FORMULA. A rainfall-runoff relation used to estimate peak flow.
REDEVELOPMENT. Earth disturbance activities on land, which has previously been developed.
REGULATED ACTIVITIES. Any earth disturbance activities or any activities that involve the alteration or development of land in a manner that may affect stormwater runoff.
REGULATED EARTH DISTURBANCE ACTIVITY. Activity involving earth disturbance subject to regulation under 25 Pa. Code Chapter 92a, Chapter 102 or the Clean Streams Law, being 35 P.S. §§ 691.1 et seq.
RELEASE RATE. The percentage of pre-development peak rate of runoff from a site or subwatershed area to which the post-development peak rate of runoff must be reduced to protect downstream areas.
RELEASE RATE DISTRICT. Those subwatershed areas in which post-development flows must be reduced to a certain percentage of pre-development flows as required to meet the plan requirements and the goals of the Stormwater Management Act, being 32 P.S. §§ 680.1 et seq.
RETENTION BASIN. An impoundment in which stormwater is stored and not released during the storm event. Stored water may be released from the basin at some time after the end of the storm.
RETENTION VOLUME/REMOVED RUNOFF. The volume of runoff that is captured and not released directly into the surface waters of this state during or after a storm event.
RETURN PERIOD. The average interval, in years, within which a storm event of a given magnitude can be expected to recur. For example, the 25-year return period rainfall would be expected to recur on the average once every 25 years; or stated in another way, the probability of a 25-year storm occurring in any one given year is 0.04 (i.e., a 4% chance).
RIPARIAN BUFFER. A vegetated area bordering perennial and intermittent streams and wetlands that serves as a protective filter to help protect streams and wetlands from the impacts of adjacent land uses.
RISER. A vertical pipe extending from the bottom of a pond that is used to control the discharge rate from the pond for a specified design storm.
ROAD MAINTENANCE. Earth disturbance activities within the existing road right-of-way, such as grading and repairing existing unpaved road surfaces, cutting road banks, cleaning or clearing drainage ditches and other similar activities. ROAD MAINTENANCE activities that do not disturb the subbase of a paved road, such as milling and overlays, are not considered earth disturbance activities.
ROOFTOP DETENTION. Temporary ponding and gradual release of stormwater falling directly onto flat roof surfaces by incorporating controlled-flow roof drains into building designs.
RUNOFF. Any part of precipitation that flows over the land surface.
RUNOFF CAPTURE VOLUME. The volume of runoff that is captured (retained) and not released info surface waters of the state during or after a storm event.
SEDIMENT. Soils or other materials transported by surface wafer as a product of erosion.
SEDIMENT BASIN. A barrier, dam, retention or detention basin located and designed to retain rock, sand, gravel, silt or other material transported by stormwater runoff.
SEDIMENT POLLUTION. The placement, discharge or any other introduction of sediment into waters of the state occurring from the failure to properly design, construct, implement or maintain control measures and control facilities in accordance with the requirements of this chapter.
SEDIMENTATION. The process by which mineral or organic matter is accumulated or deposited by the movement of water.
SEEPAGE PIT/SEEPAGE TRENCH. An area of excavated earth filled with loose stone or similar coarse material, into which surface water is directed for infiltration into the ground.
SEPARATE STORM SEWER SYSTEM. A conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, human-made channels or storm drains) primarily used for collecting and conveying stormwater runoff.
SHEET FLOW. Runoff that flows over the ground surface as a thin, even layer, not concentrated in a channel.
SOIL COVER COMPLEX METHOD. A method of runoff computation developed by the NRCS that is based on relating soil type and land use/cover to a runoff parameter called curve number (CN).
SPILLWAY (EMERGENCY). A depression in the embankment of a pond or basin, or other overflow structure, that is used to pass peak discharges greater than the maximum design storm controlled by the pond or basin.
STATE WATER QUALITY REQUIREMENTS. The regulatory requirements to protect, maintain, reclaim and restore water quality under Title 25 of the Pennsylvania Code and the Clean Streams Law, being 35 P.S. §§ 691.1 et seq.
STORAGE INDICATION METHOD. A reservoir routing procedure based on solution of the continuity equation (inflow minus outflow equals the change in storage) with outflow defined as a function of storage volume and depth.
STORM FREQUENCY. The number of times that a given storm event occurs or is exceeded on the average in a stated period of years. See also RETURN PERIOD.
STORM SEWER. A system of pipes and/or open channels that convey intercepted runoff and stormwater from other sources, but excludes domestic sewage and industrial wastes.
STORMWATER. Runoff from the surface of the land resulting from precipitation, snow or ice melt.
STORMWATER HOTSPOT. A land use or activity that generates higher concentrations of hydrocarbons, trace metals or toxicants than are found in typical stormwater runoff.
STORMWATER MANAGEMENT FACILITIES. Any structure, natural or human-made, that, due to its condition, design or construction, conveys, stores or otherwise affects stormwater runoff. Typical STORMWATER MANAGEMENT FACILITIES include, but are not limited to: detention and retention basins; open channels; storm sewers; pipes; and infiltration facilities.
STORMWATER MANAGEMENT PLAN. The Erie County Stormwater Management Plan for managing stormwater runoff in Erie County as required by the Act of October 4, 1978, P.L. 864, (Stormwater Management Act, being 32 P.S. §§ 680.1 et seq.).
STORMWATER MANAGEMENT SITE PLAN (SWM SITE PLAN). The Plan prepared by the applicant or his or her representative indicating how stormwater runoff will be managed at the project site in accordance with this chapter.
STREAM ENCLOSURE. A bridge, culvert or other structure in excess of 100 feet in length upstream to downstream which encloses a regulated waters of the state.
SUBWATERSHED AREA. The smallest drainage unit of a watershed for which stormwater management criteria has been established in the Stormwater Management Plan.
SUBDIVISION. The division or re-division of a lot, tract or parcel of land by any means into two or more lots, tracts, parcels or other divisions of land, including changes in existing lot lines for the purpose, whether immediate or future, of lease, transfer of ownership, or building or lot development, provided; however, that the SUBDIVISION by lease of land for agricultural purposes into parcels of more than ten acres, not involving any new street or easement of access or any residential dwellings, shall be exempt (the state’s Municipalities Planning Code, Act of July 31, 1968, P.L. 805, No. 247, 53 P.S. §§ 10101 et seq.)
SWALE. A low-lying stretch of land that gathers or carries surface water runoff.
TIMBER OPERATIONS. See FOREST MANAGEMENT.
TIME OF CONCENTRATION (Tc). The time for surface runoff to travel from the hydraulicaliy most distant point of the watershed to a point of interest within the watershed. This TIME is the combined total of overland flow time and flow time in pipes or channels, if any.
USDA. The United States Department of Agriculture.
WATERCOURSE. A channel or conveyance of surface water, such as a stream or creek, having defined bed and banks, whether natural or artificial, with perennial or intermittent flow.
WATERS OF THE STATE. Rivers, streams, creeks, rivulets, impoundments, ditches, watercourses, storm sewers, lakes, dammed water, wetlands, ponds, springs and other bodies or channels of conveyance of surface and underground water, or parts thereof, whether natural or artificial, within or on the boundaries of the state.
WATERSHED. Area drained by a river, watercourse or other surface water, whether natural or artificial.
WETLAND. Those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions, including swamps, marshes, bogs and similar areas. The term includes, but is not limited to, WETLAND areas listed in the State Water Plan, the United States Forest Service Wetlands Inventory of Pennsylvania, the State Coastal Zone Management Plan and a wetland area designated by a river basin commission. This definition is used by the United States Environmental Protection Agency and the United States Army Corps of Engineers.
(Ord. 1508, passed 12-20-2010)
STORMWATER MANAGEMENT STANDARDS
(A) For all regulated activities, unless specifically exempted in § 152.021:
(1) Preparation and implementation of an approved SWM Site Plan is required;
(2) No regulated activities shall commence until the municipality issues written approval of a SWM Site Plan, which demonstrates compliance with the requirements of this chapter;
(4) The SWM Site Plan approved by the municipality, shall be on-site throughout the duration of the regulated activities.
(B) 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 chapter and to meet all requirements under Title 25 of the Pennsylvania Code (including, but not limited to, Chapter 102 Erosion and Sediment Control) and the Clean Streams Law, being 35 P.S. §§ 691.1 et seq. Various BMPs and their design standards are listed in the Erosion and Sediment Pollution Control Program Manual (E&S Manual), No. 363-2134-008 (April 15, 2000), as amended and updated.
(C) For all regulated activities, stormwater BMPs shall be designed, installed, implemented, operated and maintained to meet the purposes and requirements of this chapter and to meet all requirements under Title 25 of the Pennsylvania Code and the Clean Streams Law, being 35 P.S. §§ 691.1 et seq., conform to the state’s water quality requirements, meet all requirements under the Stormwater Management Act and any more stringent requirements as determined by the municipality.
(D) The municipality may, after consultation with PADEP and the Conservation District, approve measures for meeting the state water quality requirements other than those in this chapter, provided that they meet the minimum requirements of, and do not conflict with state law, including, but not limited to, the Clean Streams Law, being 35 P.S. §§ 691.1 et seq.
(E) All regulated activities shall include, to the maximum extent practicable, measures to:
(1) Protect health, safety and property; and
(2) Meet the water quality goals of this chapter by implementing measures to:
(a) Minimize disturbance to floodplains, wetlands, natural slopes, existing native vegetation and woodlands;
(b) Create, maintain or extend riparian buffers and protect existing forested buffers;
(c) Provide trees and woodlands adjacent to impervious areas whenever feasible;
(d) Minimize the creation of impervious surfaces and the degradation of waters of the state and promote groundwater recharge;
(e) Protect natural systems and processes (drainageways, vegetation, soils, and sensitive areas) and maintain, as much as possible, the natural hydrologic regime;
(f) Incorporate natural site elements (wetlands, stream corridors and mature forests) as design elements;
(g) Avoid erosive flow conditions in natural flow pathways;
(h) Minimize soil disturbance and soil compaction;
(I) Minimize thermal impacts to waters of the state; and
(j) Disconnect impervious surfaces by directing runoff to pervious areas, wherever possible and decentralize and manage stormwater at its source.
(F) Impervious areas:
(1) The measurement of impervious areas shall include all of the impervious areas in the total proposed development, even if development is to take place in stages.
(2) For developments taking place in stages, the entire development plan must be used in determining conformance with this chapter.
(G) If diffused flow is proposed to be concentrated and discharged onto adjacent property, the applicant must document that adequate downstream conveyance facilities exist to safely transport the concentrated discharge, or otherwise prove that no erosion, sedimentation, flooding or other harm will result from the concentrated discharge.
(1) Applicant must provide an easement for proposed concentrated flow across adjacent properties to a drainage way or public right-of-way.
(2) Such stormwater flows shall be subject to the requirements of this chapter.
(H) Stormwater drainage systems shall be provided in order to permit unimpeded flow along natural watercourses, except as modified by stormwater management facilities or open channels consistent with this chapter.
(I) Where watercourses traverse a development site, drainage easements (with a minimum width of 20 feet and include the 100-year water surface) shall be provided conforming to the line of such watercourses. The terms of the easement shall prohibit excavation, the placing of fill or structures, and any alterations that may adversely affect the flow of stormwater within any portion of the easement. Also, maintenance, including mowing of vegetation within the easement may be required, except as approved by the appropriate governing authority.
(J) When it can be shown that, due to topographic conditions, natural drainageways on the site cannot adequately provide for drainage, open channels may be constructed conforming substantially to the line and grade of such natural drainageways. Work within the natural drainage ways shall be subject to approval by PADEP under regulations at 25 Pa. Code Chapter 105 through the joint permit application process, or, where deemed appropriate by PADEP, through the general permit process.
(K) Any stormwater management facilities or any facilities that constitute water obstructions (e.g., culverts, bridges, outfalls, stream enclosures and the like) that are regulated by this chapter, that will be located in or adjacent to waters of the state, including wetlands, shall be subject to approval by PADEP under regulations at 25 Pa. Code Chapter 105 through the joint permit application process, or, where deemed appropriate by PADEP, the general permit process. When there is a question whether wetlands may be involved, it is the responsibility of the applicant or his or her agent to show that the land in question cannot be classified as wetlands; otherwise, approval to work in the area must be obtained from PADEP.
(L) Should any stormwater management facility require a dam safety permit under PADEP Chapter 105, the facility shall be designed in accordance with Chapter 105 and meet the regulations of Chapter 105 concerning dam safety.
(M) Any stormwater management facilities regulated by this chapter that will be located on or discharged onto state highway rights-of-way shall be subject to approval by the Pennsylvania Department of Transportation (PennDOT).
(N) Minimization of impervious surfaces and infiltration of runoff through seepage beds, infiltration trenches and the like are encouraged, where soil conditions and geology permit, to reduce the size or eliminate the need for detention facilities.
(O) Infiltration BMPs should be dispersed throughout the site, made as shallow as practicable and located to maximize use of natural on-site infiltration features while still meeting the other requirements of this chapter.
(P) The design of facilities over karst shall include an evaluation and implementation of measures to minimize adverse effects.
(Q) Roof drains should not be connected to streets, sanitary or storm sewers or roadside ditches in order to promote overland flow and infiltration/percolation of stormwater where it is advantageous to do so. When it is more advantageous to connect directly to streets or storm sewers, then the city may permit it on a case by case basis.
(R) Applicants are encouraged to use low impact development practices to reduce the costs of complying with the requirements of this chapter and the state’s water quality requirements.
(S) When stormwater management facilities are proposed within 1,000 feet of a downstream municipality, the developer shall notify the downstream municipality and provide a copy of the SWM Plan, if requested, for review and comment.
(Ord. 1508, passed 12-20-2010)
(A) Under no circumstance shall the applicant be exempt from implementing such measures as necessary to:
(1) Meet state water quality standards and requirements;
(2) Protect health, safety and property; or
(3) Meet special requirements for high quality (HQ) and exceptional value (EV) watersheds.
(B) The applicant must utilize the following BMPs to the maximum extent practicable to receive consideration for the exemptions:
(1) Design around and limit disturbance of floodplains, wetlands, natural slopes over 15%, existing native vegetation and other sensitive and special value features;
(2) Maintain riparian and forested buffers;
(3) Limit grading and maintain non-erosive flow conditions in natural flow paths;
(4) Maintain existing tree canopies near impervious areas;
(5) Minimize soil disturbance and reclaim disturbed areas with topsoil and vegetation; and
(6) Direct runoff to pervious areas.
(C) The applicant’s proposed development/additional impervious area may not adversely impact the following:
(1) Capacities of existing drainageways and storm sewer systems;
(2) Velocities and erosion;
(3) Quality of runoff if direct discharge is proposed;
(4) Existing known problem areas;
(5) Safe conveyance of the additional runoff; and/or
(6) Downstream property owners.
(D) An applicant proposing regulated activities, after demonstrating compliance with divisions (A) through (C) above may be exempted from various requirements of this chapter according to the following table.
New Impervious Area (Square Footage) 1,2 | Applicant Must Provide |
New Impervious Area (Square Footage) 1,2 | Applicant Must Provide |
0-1,000 | - |
1,000-2,500 | Documentation of impervious area 3 |
2,500-5,000 | Volume controls and small project SWM application |
> 5,000 | Rate controls, volume controls and SWM Site Plan |
Notes: | |
(1)New impervious area since the date of adoption of this chapter. | |
(2)Gravel in existing condition shall be considered pervious and gravel in proposed condition shall be considered impervious. | |
(3)The small project stormwater management application included in Appendix E may be used for projects under 5,000 square feet of new impervious surface and single-family home construction. The small project SWM application allows documentation of new impervious surface, credits through disconnection of impervious surfaces and free planting, and sizing of volume control BMPs that may be required. | |
(E) Single-family residential activities are exempt from these requirements provided the construction:
(1) Comply with § 152.020(G) and divisions (A) through (C) above;
(2) Have building setback 75 feet from downstream property lines;
(3) Driveways:
(a) Runoff must discharge onto pervious surface with a gravel strip or other spreading device;
(b) No more than 1,000 square feet of paved surface may discharge to any one point; and
(c) The length of flow on the pervious must exceed the length of the paved surface flow.
(4) The municipality can require more information or require mitigation of certain impacts through installation of stormwater management BMPs if there is a threat to property, health or safety.
(F) An applicant proposing regulated activities, after demonstrating compliance with divisions (A) through (C) above, may be exempted from various requirements of this chapter if documentation can be provided that a downstream human-made water body (i.e., reservoir, lake, human-made wetlands or other BMP) has been designed or modified to address the potential stormwater flooding and volume impacts of the proposed development.
(G) The purpose of this section is to ensure consistency of stormwater management planning between local ordinances and NPDES permitting (when required) and to ensure that the applicant has a single and clear set of stormwater management standards to which the applicant is subject. The city may accept alternative stormwater management controls under this section provided that:
(1) The city, in consultation with the PADEP (or delegated authority), determines that meeting the volume control requirements (see § 152.023) is not possible or places an undue hardship on the applicant.
(2) The alternative controls are documented to be acceptable to PADEP, or delegated authority, for NPDES requirements pertaining to post construction stormwater management requirements.
(3) The alternative controls are in compliance with all other sections of this chapter, including but not limited to, § 152.020(D) and divisions (A) through (C) above.
(H) Agricultural activity is exempt from the rate control and SWM Site Plan preparation requirements of this chapter, provided the activities are performed according to the requirements of 25 Pa. Code Chapter 102.
(I) Forest management and timber operations are exempt from the rate and volume control requirement and SWM Site Plan preparation requirement of this chapter, provided the activities are performed according to the requirements of 25 Pa. Code Chapter 102. It should be noted that temporary roadways are not exempt.
(J) The city may deny or revoke any exemption pursuant to this section at any time for any project that the municipality believes may pose a threat to public health, safety, property or the environment.
(Ord. 1508, passed 12-20-2010)
(A) (1) All waiver requests must meet the provisions of divisions (G) below. Waivers shall not be issued from implementing such measures as necessary to:
(a) Meet state water quality standards and requirements; and
(b) Protect health, safety and property.
(B) If an applicant demonstrates to the satisfaction of the governing body of the city that any mandatory provision of this chapter is unreasonable or causes unique or undue hardship as it applies to a proposed project, and that an alternate design produces equal or better results within the context of meeting the purpose and requirements of this chapter, the governing body of the city, upon obtaining the comments and recommendations of the City Engineer, 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 chapter.
(C) Applicants shall submit requests for waivers in writing and these requests shall be included as part of a permit application submission. In the request for waiver, the applicant shall state in full the facts of undue hardship on which the request is based, identify the provision or provisions of the chapter that are causing such undue hardship and state the minimum waiver or relief that is necessary. The applicant shall state how the proposal in the applicant’s waiver request provides equal or better results in meeting the purpose and requirements of this chapter.
(D) The city shall keep a written record of all actions on waiver requests in the project file.
(E) The city may charge applicants fees for waiver requests sufficient to cover all costs incurred by the city to process the requests, including, but not limited to, administrative costs and costs for the City Engineer to review the waiver request.
(F) In granting waiver requests, the city may impose reasonable conditions that will, in its sole judgment, resolve the undue hardship while meeting the purpose and requirements of this chapter.
(G) The municipality may grant requests for waivers when the following findings are made by the city, when each is determined solely by the city to be applicable and relevant:
(1) The waiver shall result in an equal or better means of complying with the purpose and requirements of this chapter;
(2) The waiver is the minimum necessary to provide relief from undue hardship;
(3) The applicant is not requesting a waiver based solely on cost considerations;
(4) Existing down gradient stormwater problems will not be exacerbated by the proposed waiver request;
(5) Runoff is not being diverted to a different drainage area in a manner that may cause hardship to others;
(6) Increased flooding or ponding on off-site properties or roadways will not be caused by the waiver request;
(7) Potential icing conditions will not be caused by the waiver request;
(8) Increased or unusual municipal maintenance expenses will not result from the waiver request; and
(9) Operation and maintenance requirements are not reduced by the waiver request.
(Ord. 1508, passed 12-20-2010)
(A) The low impact development practices provided in the BMP Manual and in Appendix B of this chapter shall be utilized for all regulated activities to the maximum extent practicable.
(B) Stormwater runoff volume controls shall be implemented using the design storm method or the simplified method as defined below. For regulated activity areas equal or less than one acre that do not require hydrologic routing to design the stormwater facilities, this chapter establishes no preference for either method; therefore, the applicant may select either method on the basis of economic considerations, the intrinsic limitations on applicability of the analytical procedures associated with each methodology, and other factors.
(1) The design storm method (CG-I in the BMP Manual) is applicable to any sized regulated activity. This method requires detailed modeling based on site conditions.
(a) Do not increase the post-development total runoff volume for all storms equal to or less than the two-year 24-hour storm;
(b) For hydrologic modeling purposes:
1. Existing non-forested pervious areas must be considered meadow (good condition) for pre-development hydrologic calculations; and
2. Twenty percent of existing impervious area, when present within the proposed project site, shall be considered meadow (good condition) for pre-development hydrologic calculations for re-development.
(2) The simplified method (CG-2 in the BMP Manual) is independent of site conditions and should be used if the design storm method is not followed. This method is not applicable to regulated activities greater than one acre or for projects that require detailed design of stormwater storage facilities. For new impervious surfaces:
(a) Stormwater facilities shall capture at least the first two inches of runoff from all new impervious surfaces;
(b) At least the first one inch of runoff from new impervious surfaces shall be permanently removed from the runoff flow, (i.e., it shall not be released into surface waters of the state). Removal options include reuse, evaporation, transpiration and infiltration;
(c) Wherever possible, infiltration facilities should be designed to accommodate infiltration of the entire permanently removed runoff; however, in all cases at least the first half-inch of the permanently removed runoff should be infiltrated; and
(d) Actual field infiltration tests at the location of the proposed elevation of the stormwater BMPs are required. Infiltration test shall be conducted in accordance with the BMP Manual. A minimum 48-hour notification of the municipality shall be provided to allow witnessing of the testing.
(3) In cases where it is not possible or desirable to use infiltration-based best management practices to partially fulfill the requirements in either divisions (B)(1) or (B)(2) above, the following procedure shall be provided to allow witnessing of the testing.
(a) At a minimum, the following documentation shall be provided to justify the decision to reduce the use of infiltration BMPs:
1. Description of and justification for field infiltration/permeability testing with respect to the type of test and test locations);
2. An interpretive narrative describing existing site soils and their structure as these relate to the interaction between soils and water. In addition to providing soil and soil profile descriptions, this narrative shall identify depth to seasonal high water tables and depth to bedrock, and provide a description of all subsurface elements (fragipans and other restrictive layers, geology and the like) that influence the direction and rate of subsurface water movement;
3. A qualitative assessment of the site’s contribution to annual aquifer recharge shall be made, along with identification of any restrictions or limitations associated with the use of engineered infiltration facilities; and
4. The provided documentation must be signed and sealed by a professional engineer or geologist.
(b) The following water quality pollutant load reductions will be required for all disturbed areas within the proposed development.
Pollutant Load | Units | Required reduction (%) |
Total nitrate (NO3) | Pounds | 50 |
Total phosphorous (TP) | Pounds | 85 |
Total suspended solids (TSS) | Pounds | 85 |
(c) The performance criteria for water quality best management practices shall be determined from the state’s Stormwater Best Management Practices Manual most current version.
(C) The applicable worksheets from the BMP Manual must be used in calculations to establish volume control.
(Ord. 1508, passed 12-20-2010)
(A) Lands contained within the county that have not had release rates established under an approved Stormwater Management Act, 32 P.S. §§ 680.1 et seq. Post-development discharge rates shall not exceed the pre-development discharge rates for the one-year, two-year, ten-year, 25-year, 50-year and 100-year storms.
(B) Lands contained within the county that have had release rates established under an approved Stormwater Management Act, 32 P.S. §§ 680.1 et seq. The post-development peak discharge rates shall be in accordance with the approved release rate map for the following watersheds (see appendices for release rate map): Lake Erie watersheds.
(Ord. 1508, passed 12-20-2010)
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