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Upon motion by Richard P. Figaski , seconded by JosephS. K ujawa , the following
Ordinance was duly enacted, _3_ voting in favor of enactment, _0_ voting against enactment.
ORDINANCE 2011-11
An Ordinance of the Township of Millcreek, Erie County, Pennsylvania, amending and restating the Millcreek Township Stormwater Management Ordinance, No. 97-4 as amended by No. 2003-5; establishing stormwater management regulations consistent with the Erie County Act 167 County-Wide Stormwater Management Plan adopted in 2011 by the County of Erie; establishing regulations governing management of stormwater; imposing duties upon developers of land; providing for filing and administration of plans, the implementation of regulations and imposition of fees for plan fi1ing, review and administration; establishing penalties for violation and containing repealor and severability clauses.
WHEREAS, the Township of Millcreek, pursuant to authority conferred under the Stonnwater Management Act and the Pennsylvania Municipalities Planning Code, enacted on October 9, 1990 Ordinance 90-28, entitled the St01mwater Ordinance, as Articles XIII through XIX of the Township's Subdivision Ordinance; and
WHEREAS, upon adoption by the County of Erie in June 1996 of its stom1water management plan for the Lake Erie Area Watershed, the Township, by Ordinance No. 97-4, amended and restated its regulations governing stormwater management so as to conform with requirements of the County's Plan; and
WHEREAS, the Township, by Ordinance No. 2003-5, amended and restated its stonnwater management regulations; and
WHEREAS, the County of Erie in 2011 adopted a revised Act 167 County-Wide Stormwater Management Plan ("County Stonnwater Management Plan"); and
WHEREAS, the Erie County Stonnwater Management Plan has been approved by the Pennsylvania Department of Environmental Protection; and
WHEREAS, the Storm Water Management Act requires that all municipalities within the Lake Erie Area Watershed adopt st01mwater ordinances consistent with the Erie County Plan; and
WHEREAS, the Erie County Stormwater Management Plan includes provisions with which Millcreek Township Ordinance No. 97-4 as amended does not comply; and
WHEREAS, the Board of Supervisors deems it necessary and in the best interest of the public health, welfare and safety to enact a Stonnwater Ordinance which complies with the Erie County Stormwater Management Plan and addresses public concerns with stormwater management.
BE IT ENACTED AND ORDAINED by the Board of Supervisors of Millcreek Township, Erie County, Pennsylvania as follows: 68
TABLE OF CONTENTS
ARTICLE 1 - GENERAL PROVISIONS 4 · 1.01 Short Title...... :...... 4 1.02 Statement ofFindings ...... 4 1.03 Purpose ...... : .... : ... .'...... 4 1.04 Statutory Authority ...... : ...... 5 1.05 Applicability ...... :...... ·5 1.06 Compatibility With Other Requirements ...... 6 1.07 Duty of Persons Engaged in the Development of Land ...... 6 0) 1.08 Municipal Liability Disclaimer ...... : ...... 6 0 1.09 Incorporation into Subdivision 8!- Land Development Ordinance ...... 6 <.0 01 1.10 Effective Date ...... 6 .....l. 1.11 Severability ...... 6 -....! 1.12 Repealor ...... : ...... 6 1 ARTICLE 2 - DEFINITIONS 7 2.01 General Provisions ...... 7 2.02 Specific Terms Defmed ...... _...... :...... 7
ARTICLE 3 - STORMWATER MANAGEMENT STANDARDS 16 3.01 General Requiretnents ...... 16 3.02 Stormwater Management Standards; Calculation Methodology ...... 20 3.03 Application of Standards ...... 24 3.04 Volume Controls ...... 25 3.05 Rate Controls ...... 27 3.06 Grading Plans Where Ordinance Not Applicable ...... :...... 27 3.07 Modification of Approved Plans Prohibited ...... 27
ARTICLE 4- EROSION AND SEDIMENTATION CONTROLS 27 4.01 Erosion and Sedimentation Control Requirements ...... 27
ARTICLE 5- DESIGN CRITERIA FOR STORMWATER MANAGEMENT CONTROLS 28 5.01 General Criteria ...... : ...... 28 5.02 General Design Criteria for Stormwater Management and Drainage Facilities ...... 29 5.03 Design Criteria for Infiltration Systems ...... '...... 30 5.04 Design Criteria for Flow-Attenuation Facilities ...... 30 5.05 Design Criteria for St01mwater Detention Facilities ...... 31 5.06 Design Criteria for Collection/Conveyance Facilities ...... 36
ARTICLE 6- SWM SITE PLAN AND REPORT REQUIREMENTS 40 6.01 General Requirements ...... 40 6.02 General Exemptions ...... }~ ...... 40 6.03 SWM Site Plan and Report Contents ...... 42 6.04 SWM Site•Plan and Report Submission ...... 49
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TABLE OF CONTENTS
ARTICLE 7- PLAN REVIEW PROCEDURES 50 7.01 Pre-Application Phase ...... 50 7.02 SWM Site Plan and Report Reviews ..... : .... : ...... 50 7.03 Modification ofPlans ...... 52 7.04 Resubmission of Disapproved SWM Site Plan and Report ...... 52 7.05 Authorization to Construct and Term of Validity ...... 52 7.06 Record Drawings, Completion Certificate and Final Inspection ...... 53 7.07 Import of Stormwater Management Plan ...... : ...... 53
ARTICLE 8- EASEMENTS· 54 8.01 Easements Generally ...... 54 8.02 Recording of Easement Interests ...... 54 1 ARTICLE 9 - MAINTENANCE OF STORMWA TER MANAGEMENT CONTROLS 55 9.01 Maintenance Responsibilities ...... 55 9.02 Maintenance Agreement for Privately-Owned Stormwater Facilities ...... 56 9.03 Miscellaneous Provisions ...... : ...... 57
ARTICLE 10- INSPECTIONS OF STORMWATE R MANAGEMENT CONTROLS 58 10.01 Inspections ...... : ...... 58 10.02 Schedule oflnspections ...... 59 10.03 Right of Entry ...... 59
ARTICLE 11 - FINANCIAL GUARANTEES/DEDICATION OF PUBLIC IMPROVEMENTS 60 11.01 Financial Guarantees...... 60 11.02 Dedication ofPublic Improvements...... 60 11.03 Express Conditions Upon Acceptance of Dedication...... 61
ARTICLE 12 - FEES AND ADMINISTRATION 62 12.01 Fee Schedule ...... :...... 62 12.02 Developer Obligated to Pay All Fees ...... 62 12.03 Aruninistration ...... : .. :...... 62 12.04 Modifications ...... :...... 62
ARTICLE 13 - PROHIBITED ACTS; ENFORCEMENT PROCEDURES AND REMEDIES 63 13.01 Prohibited Acts ...... 63 13.02 Notification ...... 64 13.03 Preventive Remedies ...... :...... 64 13.04 Enforcement Remedies ...... 65 J~ ARTICLE 14 -MISCELLANEOUS PROVISIONS 66 14.01 Appendices Incorporated ...... 66 14.02 Authority of Board of Supervisors ...... 66
APPENDIX A- RELEASE RATE MAP AND ASSIGNED PERCENTAGES APPENDIX B -PERMISSIBLE VELOCITIES FOR CHANNELS APPENDIX C- SIMPLIFIED SWM METHOD DETAIL APPENDIX D- STORMWATER MANAGEMENT DESIGN CRITERIA
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ARTICLE 1 GENERAL PROVISIONS
1.01 -Short Title
This Ordinance shall be lmown as the "Millcreek Township Stormwater M:;magement Ordinance."
1.02 - Statement of Findings
The Board of Supel'lisors :finds that:
(I) Inadequate management. of accelerated st01mwater runoff resulting from development throughout a watershed increases flood flows and velocities, contributes to erosion and sedimentation, overtaxes the carrying capacity of existing streams and storm sewers, greatly increases the cost of public facilities to convey and manage stonnwater, undennines floodplain management and flood reductio? efforts in upsh·eam and downstream communities, reduces groundwater recharge, threatens public health and safety, and increases non-point source pollution of water resources.
(2) A comprehensive program of stormwater management, including reasonable regulation of development and activities causing accelerated mnoff, is fundamental to the public health, safety, welfare, and the protection of the people of the Township, their resources, and the environment.
(3} Inadequate planning and management of stonnwater nmoff resulting from land development and redevelopment throughout a watershed can also harm surface water resources by changing the natural hydrologic patterns; accelerating stream flows (which increase scour and erosion ofstream beds and stream banks thereby elevating sedimentation); destroying aquatic habitat; elevating aquatic pollutant concenh·ations and loadings such as sediments, nutrients, heavy metals and pathogens; and impacting groundwater resources through loss of recharge.
(4) Stonnwater is an important water resource which provides groundwater recharge for water supplies and base flow of streams, which also protects and maintains surface water quality.
(5) Public education on the control of pollution from stonnwater is an essential component in successfully addressing stormwater issues. Federal. and state regulations require certain municipalities to implement a program of stormwater controls. Tlu~se municipalities are required to obtain a permit for storm water discharges from their separate storm sewer systems under the National Pollutant Discharge Elimination System (NPDES).
(6) Non-stormwater discharges to municipal separate storm sewer systems can contribute to pollution qf waters of the Commonwealth.
1.03 - Purpose l!, This Ordinance is intended to promote the health, safety and welfare within the Township by minimizing the harms and maximizing the benefits described in this Ordinance through provisions intended to:
1.03 .1 Meet legal water quality requirements under state law, including regulations at 25 Pa. Code Chapter 93 to protect, maintain, reclaim and restore the existing and designated uses of the waters of the Commonwealth.
1.03 .2 Manage accelerated runoff and erosion and sedimentation problems close to their source, by regulating activities that cause these problems. ·
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1.03.3 Utilize and preserve the existing natural drainage systems and preserve the flood-carrying capacity of streams.
1.03 .4 Maintain groundwater recharge, to prevent degradation of surface and groundwater quality and to otherwise protect water resources.
1.03.5 Maintain existing flows and quality of streams and watercourses.
1.03.6 Preserve and restore the flood-carrying capacity of streams and prevent scour and erosion of stream banks and stream beds.
1. 03.7 Manage stormwater impacts close to the runoff source, with a minimum of structures and a maximum use of natural processes.
1. 03.8 Provide procedures, performance standards and design criteria for stormwater planning and management.
1.03.9 Provide proper operations and maintenance of all stormwater management facilities and Best Management Practices (BMPs) that are constructed and implemented.
1.03.10 Provide standards to meet the NPDES permit requirements.
1.03.11 Implement an illicit discharge detection and elimination program to address non-stormwater discharges into Millcreek's separate storm sewer system.
1.04 - Statutory Authority
The Township of Millcreek is empowered to regulate these activities by the authority of the Pennsylvania Storm Water Management Act, 32 P.S. § 680.1, et seq., as amended and the Second Class Township Code, 53 P.S. § 65101, et seq., as amended. The Township is further empowered to regulate land use and development by the Pennsylvania Municipalities Planning Code, 53 P.S. § 10101, et seq., as amended.
1.05 - Applicability
This Ordinance shall apply to all areas of Millcreek Township, any Regulated Activity within the Township and all stormwater runoff entering into the Township's separate storm sewer system fi:om lands within the boundaries of Millcreek Township. Regulated Activities include, but are not limited to the following items:
1.05.1 Subdivision
1.05.2 Land Development
1.05.3 Construction of new or additional impervious or semi-pervious surfaces (e.g., driveways, parking lots)
1.05.4 Construction of new buildings or structures or additions to existing buildings or structures
1.05.5 Diversion or piping of any' natural or man-made stream chmmel
1.05.6 Installation, replacement or substantial repair of stormwater systems or appurtenances thereto
1.05.7 Earth Disturbance Activities
1.05.8 Installation of stormwater BMPs
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1.06 - Compatibility with Other Requirements
Approvals issued and actions taken pursuant to this Ordinance do not relieve an Applicant of the responsibility to comply with or to secure required pennits or approvals for activities regulated by any other applicable laws, codes, statutes, ordinances, rules or regulations. To the extent that this Ordinance imposes more rigorous or stringent requirements for stonnwater management, the specific requirements contained in this Ordinance shall be followed.
1.07-Duty of Persons Engaged in the Development of Land
Notwithstanding any provision(s) of this Ordinance, including exemptions, any landowner or any person engaged in the alteration or development of land which may affect stormwater runoff characteristics shall implement such measmes as are reasonably necessary to prevent injmy 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.
1.08 - Municipal Liability Disclaimer
1.08.1. Neither the grant nor denial of any approval under the provisions of this Ordinance, nor the compliance with the provisions of this Ordinance, or with any condition imposed by the Township, its officials, employees or representatives 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 for such damages upon the Township, its officials, employees and/or representatives.
1.08.2 The granting of a permit which includes any stormwater management facilities shall not constitute a representation, guarantee or warranty of any kind by the Township, or by an official, employee, solicitor, and consulting engineer thereof, of the practicability or safety of any stmcture, use or other plan proposed, and shall create no liability upon or cause of action against any official, employee, or designated representative for any damage that may result pursuant thereto.
1.09 - Incorporation Into Subdivision & Land Development Ordinance
Upon its effective date, this Ordinance shall amend and restate all prior ordinances governing stonnwater management and shall be that St01mwater Management Ordinance incorporated by reference in Article 13 of the Subdivision and Land Development Ordinance, No. 2006-9 as amended.
1.10 -Effective Date
This Ordinance shall become effective five (5) days after the date of its enactment.
1.11 - Severability
Should any section or provision of this Ordinance be declared invalid by a court of competent jurisdiction, such decision shall not affect the validity of this Ordinance as a whole or any other part hereof; the parts or sections remaining shall remain in effect as if the part ofthe section declared unconstitutional had never been a part of this Ordinance.
1.12 - Repealor
This Ordinance shall repeal all other ordinances, or parts thereof, which are conh·ruy to or conflict with the provisions of this Ordinance to the extent necessary to give this Ordinance full force and effect.
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ARTICLE 2 DEFINITIONS
2.01 - General Provisions
2.01.1 Words used in the present tense include the future tense; the singular number includes the plural; the plural number includes the singular; words of one gender include the other gender.
2.0 1.2 The words "include" or "including" shall not limit the term to the specific example, but are intended to extend their meaning to all other instances of like kind and character.
2.01.3 The words "shall" and "must" are mandatory. The words "may" and "should" are permissive.
2.01.4 The words "used or occupied" include the words "intended, designed, maintained or ananged to be used, occupied or maintained."
2.0 1.5 Tetms not defined in this Ordinance shall be define9 in accordance with their definitions in other ordinances of the Township or in the Second Class Township Code, the Storm Water Management Act and/or the Municipalities Planning Code ("MPC").
2.01.6 Tetms, words and phrases not specifically defined in this Ordinance shall be given their common, ordinary and customary meaning as shall effectuate the provisions and intention of this Ordinance.
2.02 - Specific Terms Defined
When used in this Ordinance, the following terms shall be defined as set fmtb below:
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 that which would occur because of the natural process alone.
Act- The Stotm WaterManagementAct(ActofOctober4, 1978,P.L. 864 No. 167; 32P.S. Sections 680.1- 680.17, as amended by Act ofMay 24, 1984, No. 63).
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 Millcreek Township.
Best Management Practices (BMPs)-Activities, facilities, designs, measures or procedures used to manage stonnwater impacts from Regulated Activities, to meet State Water Quality Requirements, to promote groundwater recharge and to otherwise meet the purposes of this Ordinance. Stmmwater 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 storm water runoff whereas "structural" BMPs are measures that consist of a physical device or practice that is installed to capture and treat stmmwater runoff. "Structural" BMPs include, but are not limited to, a wide variety of practices and devices, from large-scale retention ponds and constmcted 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" sto1mwater BMPs are permanent appurtenances to the project site.
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Channel Erosion -The widening, deepening, and headward cutting of small channels and waterways, due to erosion caused by moderate to large floods.
Cistern - An underground reservoir or tank used for storing rainwater.
Conservation District- The Erie County Conservation District, which has the authority under a delegation agreement executed with the PaDEP to administer and enforce all or a portion ofthe regulations promulgated under 25 Pa. Code Chapter 102.
Culvert-A structure with appmtenant works that carries a stream and/or stormwater runoffunder or through an embankment or fill.
Dam - An artificial barrier, together with its appurtenant works, constructed for the purpose ofimpounding or storing water or another fluid or semifluid or refuse bank, fill or structure for highway, railroad or other purposes which does or may impound water or another fluid or semifluid.
Design Criteria- (1) Engineering guidelines specifying construction details and materials. (2) Objectives, results, or limits which must be met by a facility, structure, or process in performance of its intended functions.
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 the Township and/or agent of the Board of Supervisors involved with the administration, review or enforcement of any provisions of this Ordinance by contract or memorandum of understanding.
Detention - The slowing, dampening or attenuating of runoff flows entering the natural draip.age pattern or storm drainage system by temporarily holding water on a surface area in a detention basin or within the drainage system.
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 ofth~ Commonwealth at a controlled rate.
Developer- The person(s), corporation, limited liability company, partnership, association, or other entity or any responsible person therein or agent therefor that undertakes any Regulated Activity under this Ordinance.
Development- Any activity, construction, alteration, change in land use or practice that affects stormwater runoff characteristics and/or constitutes a Regulated Activity.
Development Site (Site) -The specific tract of land for which a Regulated Activity is proposed. Also see .Project Site.
Discharge- The flow or rate of flow from a canal, conduit, channel or other hydraulic snucture.
Disturbed Area - An unstabilized land area where an Earth Disturbance Activity is occuning or has occurred.
Downslope Property L ine - That portion of the property line of the lot, tract or parcels of land being developed located such that all overland or pipe flow from the site would be directed toward it. 8 75
Drainage- In general, the removal of surface water fi:om a given area. Commonly applied to surface water and ground water.
Drainage Area - (1) The area of a drainage basin or watershed, expressed in acres, square miles, or other unit of area. Also called catchment area, watershed, river basin. (2) The area served by a sewer system receiving storm and surface water, or by a watercourse.
Drainage Conveyance Facility - A storm water management facility designed to convey stormwater runoff and shall include streams, channels, swales, pipes, conduits, culverts, storm sewers, etc.
Drainage Easement- A right granted by the owner ofproperty to use private land ofanother 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.
E arth Distu1·bance Activity-A construction or other human activity which disturbs the surface of the land, including but not limited to cle~ring 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.
E ncroachment- Any structure or activity which in any manner changes, expands or diminishes, the course, current or cross section of any watercourse, flood way or body of water.
E rosion - The movement of soil particles by the action of water, wind, ice or other natural forces.
E rosion and Sedimentation Control Plan -A plan which is designed to minimize accelerated erosion and sedimentation.
Exceptional Value Waters- Smface waters of high quality, which satisfy Pa. Code Chapter 93 (Water Quality Standards) Section 93.4b(b), relating to anti-degradation.
E xisting Conditions- The initial condition of a project site prior to the proposed construction. Ifthe initial condition of the site is undeveloped land and not forested, the land use shall be considered as "meadow" unless the natmal land cover is documented to generate lower Curve Numbers or Rational "C" Coefficient [to the extent these are authorized by this Ordinance].
FEMA -The Federal Emergency Management Agency.
F lood- A general but temporary condition ofpartial or complete inundation of normally dry land areas from the overflow of streams, rivers, and other waters of the Commonwealth.
Flood Fringe -The remaining portions of the 100-year floodplain outside of the floodway boundary.
F loodplain -Any land area susceptible to inundation by water from any natural source or delineated by applicable Depattment ofHousing 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 PaDEP Technical Ma1mal for Sewage Enforcement Officers (as amended or replaced from time to time by PaDEP).
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Floodway - The channel of the watercourse and those portions of the adjoining floodplains that are reasonably required to cany and discharge the 100-year frequency flood. Unless otherwise specified, the boundruy of the floodwa y 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 flood way 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 offorest land. These include timber inventory and preparation of forest management plans, silvicultmal 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.
Ground Water- Subsurface water occupying the saturation zone, from which wells and springs are fed.
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 Erie County for the Act 167 Plan. 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 offish, shellfish, and wildlife and recreation in and on the water by satisfying Pa. Code Title 25, Chapter 93 [Water Quality Standards] Section 93.4b(a).
Hyd!·ologic Soil Group (HSG) - Infiltration rates of soils vaty 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 Natw·al Resource Conservation Service (NRCS) of the U.S. Deprutment 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 Conservation District.
Impervious- Not allowing or allowing only with great difficulty the movement of water; impermeable.
Impervious Surface (Impervious Area) - A smface that prevents the infiltration of water into the ground. Impervious suTface (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- (1) The flow or movement of water through the interstices or pores of a soil or other porous medium. (2) The absorption of liquid by the soil.
Infiltration Structure- A stmcture designed to direct runoff into the ground (e.g., french drains, seepage pits, seepage trench, etc.).
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Inlet-A surface co1mection to a closed drain. A structme at the diversion end of a conduit. The upstream end of any structure through which water may flow.
Land Development (Development) - (i) The improvement of one lot or two or more contiguous lots, tracts or parcels of land for any purpose involving (a) a group of two or more buildings, or (b) 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; (ii) Any subdivision of land; (ill) Development in accordance with Section 503(1.1) of the MPC.
Main Stem (Main Channel) -Any stream segment or other nmoff conveyance facility used as a reach in the Erie County Act 167 watershed hydrologic model(s).
Maintenance - The upkeep necessary for efficient operation of physical properties.
Manning E quation (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 pressme.
Municipality/Township - The Township of Millcreek, Erie County, PeJIDsylvania.
National Pollutant Discharge Elimination System (NPDES)-The federal govemment's system for issuance of permits under the Clean Water Act, which is delegated toPADEP in Pennsylvania.
Natural Stormwater Runoff Regime - A watershed where natural surface configurations, runoff characteristics and defmed drainage conveyances have attained the conditions of equilibrium.
NOAA Atlas 14: -Precipitation-Frequency Atlas ofthe 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).
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 Ch.annel - A drainage element in which stormwater flows with an open surface. Open channels include, but shall not be limited to, natural and man-made drainageways, swales, streams, ditches, canals, and pipes not under pressure.
Outfall - (i) Point where water flows from a conduit, stream, or drain; (ii) "Point Source" as described in 40 CFR § 122.2 at the point where the Municipality's stonn sewer system discharges to surface waters of the Commonwealth.
Outlet -Points of water disposal from a stream, river, lake, tidewater, or artificial drain.
Outlet Control Structure - The means ofcontrolling the relationship between the headwater elevation and the discharge, placed at the outlet or downstTeam end of any structure through which water may flow.
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 Dischar ge - The maximum rate of stormwater runoff from a specific storm event.
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Peale Flow - Maximum rate of flow.
Performance Standard- A standard which establishes an end result or outcome which is to be achieved but does not prescribe specific means for achieving it.
Person -An individual, partnership, public or private association or corporation, limited liability company, firm, trust, estate, municipality, governmental unit, public utility or any other legal entity whatsoever which is recognized by law as the subject ofrights 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 Commonwealth.
Pervious Area - Any area not defined as impervious.
Pipe- A culvert, closed conduit, or similar structure (including appurtenances) that conveys stonnwater.
P lanning Commission- The Planning Commission of Millcreek Township.
Point Source - Any discernible, confined, or discrete conveyance, including, but not limited to: any pipe, ditch, channel, tunnel, or conduit from which stormwater is or may be discharged, as defined in State regulations at 25 Pennsylvania Code§ 92.1.
Pred~velopment Conditions- Predevelopment conditions shall be assumed to be those which existed on the site at the time prior to commencement of any development activities. Where a site has been developed previously and is proposed to be redeveloped, the predevelopment coefficient for the developed portion of the site shall be based upon an assumed fifty percent (50%) native land cover (i.e., grass, trees, etc.) and fifty percent (50%) developed land cover (e.g., buildings, pavement, etc.).
Project Site - The specific area of land where any Regulated Activities in the Municipality are planned, conducted, or maintained.
Public and P rivate Improvements Code ("PPIC") - The Millcreek Township Public and Private Improvements Code, as may in the future be amended.
Qualified Professional - Any person licensed by the PennsylvaniaDepattmentofState or otherwise qualified by law and meeting requirements of this ordinance to perform the work required by the Ordinance.
Rational Formula - A rainfall-runoffrelation used only to estimate peak flow rates for design of conveyance facilities.
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 storm water runoff.
Regulated Earth Disturbance Activity- Activity involving Earth Disturbance subject to regulation under 25 Pa. Code Chapter 92, Chapter 102, or the Clean Streams Law.
Release Rate - The percentage of pre-development peak rate of runoff from a site or sub-watershed area to which the post-development peak rate of runoff must be reduced to protect downstream areas.
Release Rate Distr ict -Those sub-watershed areas in which post-development flows must be reduced to a certain percentage ofpre-development flows as required by this Ordinance to meet the plan requirements and the goals of Act 167.
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Retention Basin - An impoundment in which stormwater is stored and not released during the storm event. Stored water may be released from the basin at some time after the end of the storm.
Retention Volume/Removed Runoff- The volume of runoff that is captured and not released directly into the surface Waters of this Commonwealth during or after a storm event.
Return Period -The average interval, in years, within which a storm event of a given magnitude can be expected to recur. For example, the 25-year return period rainfall would be expected to recur on the average once every twenty-five 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 into surface Waters of the Commonwealth during or after a storm event.
Runoff Characteristics - The surface components of any watershed which affect the rate, amount, and direction of storm water runoff. These may include but are not limited to: vegetation, soils, slopes and man made landscape alterations.
Sediment- Soils or other materials transported by surface water as a product of erosion.
Sediment Basin - A barrier, dam, retention or detention basin located and designed to retain rock, sand, gravel, silt, or other material transpmted by stormwater runoff.
Sediment Pollution - The placement, discharge, or any other introduction of sediment into waters of the Commonwealth occulTing from the failure to properly design, construct, implement or maintain control measures and control facilities in accordance with the requirements of this Ordinance.
Sedimentation - The process by which mineral or organic matter is accumulated or deposited by the movement of water.
Seepage Pit/Seepage Trench -An area of excavated earth filled with loose stone or similar coarse material, into which surface water is directed for infiltration into the ground.
Separate Storm Sewer System - A conveyance or system of conveyances (including roads with drainage systems, Township streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains) primarily used for collecting and conveyfug stonnwater runoff.
Sheet Flow-Runoff that flows over the ground surface as a thin, even layer, not concentrated in a channel.
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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.
Storage Facility- See detention basin and retention basin.
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 stonn "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 st01mwater 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 Collection System - Natural or man-made structures that collect and transport stormwater through or from a drainage area to the point of final outlet including, but not limited to, any of the following: conduits and appurtenant features, canals, channels, ditches, streams, culverts, streets, and pumping stations.
Stormwater Hotspot - A land use or activity that generates higher concentrations of hydrocarbons, trace metals, or toxicants than are found in typical stormwater runoff.
Stormwater Management Facilities-Any structure, natural or man-made, that, due to its condition, design, or construction, conveys, stores, or otherwise affects stormwater runoff. Typical stonnwater management facilities include, but are not limited to: detention and retention basins, open chatmels, storm sewers, pipes and infiltration facilities.
Stormwater Management Plan -The Erie County Stormwater Management Plan for managing st01mwater runoff in Erie County as required by Act 167 of 1978, known as the Storm Water Management Act.
Stormwater Management Site Plan (SWM Site Plan) - The plan prepared by the Applicant or his representative indicating how stormwater runoff will be managed at the project site in accordance with this Ordinance.
Storm Water Management Model (SWMM) -a dynamic rainfall-runoff simulation model used for single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas.
Str eam Enclosure - A bridge, culvert, or other structure in excess of 100 feet in length upstream to downstream which encloses a regulated waters of the Commonwealth.
Sub-watershed Area-The smallest drainage unit of a watershed for which stormwater management criteria has been established in the Stormwater Management Plan.
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Subdivision -The division or_re-division of a lot, tract, or parcel ofland by any means, into two or more Jots, 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. ·
Swale -A low-lying stretch of land that gathers or carries surface water runoff.
Timber Operations- See "Forest Management".
Time of Concentration (T.)-The time for surface runoff to travel from the hydraulically most distant point of the watershed to a point of interest within the watershed. This time is the combined total of overland flow time and flow time in pipes or channels, if any.
Township Engineer - A professional engineer licensed in the Commonwealth of Pennsylvania, duly appointed by the Township and/or retained by the Township to assist in implementation of this Ordinance.
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 intetmittent flow.
Waters of the Commonwealth- Rivers, streams, creeks, rivulets, impoundments, ditches, watercourses, storm sewers, lakes, dammed water, wetlands, ponds, springs and other bodies or channels of conveyance of surface and underground water, or parts thereof, whether natural or artificial, within or on the boundaries of the Commonwealth of Pennsylvania.
Watershed- Area drained by a river, watercourse, or other surface water, whether natural or artificial.
Wetland-Those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions, including swamps, marshes, bogs and similar areas. (The term includes but is not limited to wetland areas listed in the State Water Plan, the U.S. Forest Service Wetlands Inventory of Pennsylvania, the Pennsylvania Coastal Zone Management Plan and a wetland area designated by a river basin commission. This definition is used by the U.S. Environmental Protection Agency and the U.S. Army Corps of Engineers.)
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ARTICLE3 STORMWATE R MANAGEMENT STANDARDS
3.01 -General Requirements
3.01.1 For all Regulated Activities, unless specifically exempted in Section 6.02:
(1) Preparation and implementation of an approved SWM Site Plan is required.
(2) No Regulated Activities shall commence until the Township issues written approval of a SWM Site Plan, which demonstrates compliance with the requirements of this Ordinance.
(3) The SWM Site Plan shall demonstrate that adequate capacity will be provided to meet the Volume and Rate Control Requirements, as described under Sections 3.04 and 3.05 of this Ordinance.
(4) The SWM Site Plan as approved by the Township shall be on-site throughout the duration of the Regulated Activities.
3.0 1.2 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 Ordinance and to meet all requirements under Title 25 ofthe Pennsylvania Code (including, but not limited to Chapter 102 [Erosion and Sediment Control] and the Clean Streams Law. Various BMPs and their design standards are listed in the Erosion and Sediment Pollution Control Program Manual (E&S Manual), No. 363-2134-008 (April 15, 2000), as amended and updated.
3.01.3 For all Regulated Activities, stormwater BMPs shall be designed, installed, implemented, operated, and maintained to meet the purposes and requirements of this Ordinance and to meet all requirements under Title 25 of the Pennsylvania Code and the Clean Streams Law, conform to the State Water Quality Requirements, meet all requirements under the St01m Water Management Act and any more stringent requirements as determined by the Township.
3.01.4 The Township, after consultation with PaDEP and the Conservation District and with their written approval, may approve measures for meeting the State Water Quality Requirements other than those in this Ordinance, provided that they meet the minimum requirements of, and do not conflict with state law, including, but not limited to, the Clean Streams Law.
3.01.5 All Regulated Activities shall include, to the maximum extent practicable, measures to:
(1) Protect health, safety, and property.
(2) Meet the water quality goals of this Ordinance by implementing measures to:
( i) Minimize disturbance to floodplains, wetlands, natura!' slopes, existing native vegetation and woodlands;
(ii) Create, maintain, or extend riparian buffers and protect existing forested buffers;
(iii) Provide trees and woodlands adjacent to unpervious areas whenever feasible;
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(iv) Minimize the creation of impervious smfaces and the degradation of waters of the Commonwealth and promote groundwater recharge;
( v) Protect natural systems and processes (drainageways, vegetation, soils, and sensitive areas) and maintain, as much as possible, the natural hydrologic regime;
(vi) fucorporate natural site elements (e.g., wetlands, stream corridors, mature forests) as design elements;
(vii) Avoid erosive flow conditions in natural flow pathways;
(viii) Minimize soil distmbance and soil compaction;
(ix) Minimize thermal impacts to waters of the Commonwealth; and
( x) Disconnect impervious surfaces by directing runoffto pervious areas, wherever possible and decentralize and manage stmmwater at its source.
3.01.6 Impervious Areas.
(1) The measurement of impervious areas shal I include all of the impervious areas in the total 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 Ordinance.
(3) For projects which add impervious area to a parcel or involve redevelopment of a previously developed parcel, the predevelopment coefficient shall be as-calculated under Predevelopment Conditions -see Section 3.02.3.
3.0 1. 7 If diffused flow is proposed to be concenb·ated and discharged onto adjacent property(ies), the Applicant must document that adequate downstream conveyance facilities exist to safely b·ansport 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 the proposed concentrated flow across adjacent properties to a dJainage way or public right of way.
(2) Such stonnwater flows shall be subject to the requirements of this Ordinance.
3.01.8 St01mwater drainage systems shall be provided in order to permit unimpeded flow along natuJal watercourses, except as modified by stormwater management facilities or open channels consistent with this Ordinance.
3.01.9 Where watercourses traverse a development site, drainage easements (with a minimum width of20 feet and including the 100-year water surface) shall be provided as a condition of plan approval, conforming to the line of such watercourse(s)
(1) The width of such easement shall be adequate to provide for unimpeded flow of stormwater runoff based on calculations made in accordance with Sections 3.02 and 3.04 for the 100-year return period runoff and to provide a freeboard allowance of one-half foot (0.5') above the design water surface level.
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(2) The terms of the easement shall prohibit excavation, the placing of fill, structures, shrubbery, trees, fences, structures, and/or any alterations that may adversely affect the flow of stonnwater within any portion of the easement without the Township's prior written approval.
(3) Also, maintenance, including mowing of vegetation within the easement may be required, except as approved by the Township.
3.01.10 When it can be shown that, due to topographic conditions, natural drainageways on the site cannot adequately provide for drainage, open channels may be constructed conforming substantially to the line and grade of such natural drainageways.
3.01.11 Design storm volumes and precipitation intensities to be used in the analysis of discharge or runoff shall be obtained from either of the following sources:
(1) The Precipitation-Frequency Atlas of the United States, Atlas 14, Volume 2, Version 3.0, U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), National Weather Service, Hydrometeorological Design Studies Center, Silver Spring, Maryland. NOAA's Atlas 145 can be accessed at: http://hdsc.nws.noaa.gov/hdsc/pfds.
(2) The Pennsylvania Department ofTransportationDrainage Manual, Publication 584, Chapter 7, Appendix A.
3.01 .12 Any drainage facilities required by this Ordinance which are located within State highway rights of way and/or which may discharge into conveyance facilities within the State highway right of way shall be subject to the prior approval of the Pennsylvania Department of Transportation ("PennDOT")
( 1) Millcreek Township will not be responsible, nor shall it accept responsibility for any stormwater management facilities located within or discharging into conveyance facilities within the State highway right of way.
3.01.13 Stormwater management facilities and appurtenances shall be designed and provided so as to minimize erosion in watercourses and at all points of discharge.
3.01.14 All natural or man-made charu1els or swales must be able to convey the incteased runoff associated with a 2-year return period within their banks at velocities consistent with the protection of the channels from erosion. Acceptable velocities shall be based upon criteria set forth in the PaDEP Soil Erosioll and Sedimentation Control Manual, and Appendix B to this Ordinance [Permissible Velocities for Channels], which is incorporated herein.
3.01.15 The developer shall ensure that all flows in excess of a 25-year design storm sewer flow up to and including the 100-year storm discharge from the developed site shall be adequately conveyed to the detention basin via an adequately sized storm sewer system, a designated swale and/or channel or a combination of such facilities in such manner as will protect against public inconvenience and injury to property or persons.
3.01.16 All stormwater management facilities shall be constructed in accordance with the standards and specifications set forth in the Millcreek Township Public and Private Improvements Code, Ordinance No. 2003-3, as amended, or the regulations of an authority or other governmental agency having authority over the improvement.
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3.01.17 A developer shall submit to the Township Engineer and to the engineer retained to review stormwater management plans a listing of all materials proposed to be used prior to commencement of construction.
3.01.18 Minimization of impervious surfaces and infiltration of runoff through seepage beds, infiltration trenches, etc. are encouraged, where soil conditions and geology petmit, to reduce the size or eliminate the need for detention facilities.
3.01.19 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 Ordinance.
3.01.20 The design of facilities over karst shall include an evaluation and implementation of measures to minimize adverse effects.
3.01.21 Roof drains should not be connected to streets, stmm sewers or roadside ditches and shall not be connected to sanitary sewers.
3.01.22 When stonnwater management facilities are proposed within 1,000 feet of a downstream municipality, the Developer shall notify the downstream municipality and provide to it a copy of the SWM Plan, if requested, for review and comment. See also Sections 6.03.2.1 O(vii) 51nd 7.02.1. \ 3.01.23 Applicants are encouraged to use Low Impact Development Practices to reduce the costs of complying with the requirements of this Ordinance and the State Water Quality Requirements.
3.01.24 Sump pump and ground water discharges shall be directly connected to a storm sewer.
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3.02 - Stormwater Management Standards; Calculation Methodology
The stormwater performance standards contained in this Section are intended to implement the standards and q·iteria contained in the Erie County Stormwater Management Plan, adopted, and approved in accordance with the Act. If there is any discrepancy between the provisions of this Section and the standards and criteria of the Plan, or if the County's Stonnwater 1y.faoagement Plan is subsequently amended, then the standards/criteria of this Section shall control if they are more stringent than those in the Plan and those of the Plan or amended watershed plan shall govern if they are more stringent than those in this Ordinance.
3 .02.1 Storm Frequencies/Rainfall Values. Stonnwater management facilities on all development sites shall c~ntrol the peak stormwater discharge for the 2-, 10-,25-, 50-and 1 00-year storm frequencies. The 24-hour total rainfall for these storm frequencies in the Township are:
Retum In ter~a l 24-hour Rainfall Total (Year) (inches)
1-year 2.13 2-year 2.56 10-year 3.71 25-year 4.46 50-year 5.09 100-year 5.76
3.02.2 Calculation Methodo~ogy.
(I) All calculations shall be consistent with the guidelines set forth in the BMP Manual, as amended herein.
(2) Runoff Calculation: The NRCS 24-hour, Type IT Rainfall Distribution shall be used for analyzing stormwater runoff for both pre- and post-development conditions.
(3) Development Sites: For the purpose of computing peak flow rates and runoff hydro graphs from development sites, calculations shall be performed using one of the following: Soil Cover Complex (SCS) Method, Technical Release (TR) 55 or 20, or the HEC I or Penn State Runoff Model (PSRM) or Storm Water Management Model (SWMM). Under special circumstances, the Township may approve use of other computation methods.
(4) The Rational Method shall not be used to calculate runoff volume.
(5) Peak Flow Rates:
( i/ The NRCS RainfaLL-RunoffMethod is recommended for design of stonnwater management facilities and where stormwater runoff must be taken into consideration. As to the model applicability: (a) there are no size limitations as to NRCS' TR-20 orHEC-HMS and SWMM; (b) other models shall be as pre approved ~y the Township. Other methods upon approval by the Township may be applied.
(ii) The NRCS antecedent mnoff condition II (ARC IT, previously AMC IT) must be used for all simulations. Use of continuous simulation models that vaty the ARC is not permitted for stonnwater management purposes.
(iii) Rainfall intensities for design should be obtained from those sources authorized in Section 3. 01 .1 1, above.
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(iv) The Rational Method may be used for design of conveyance facilities only. Extreme caution should be used by the design professional if the watershed has more than one main drainage channel. If the watershed is divided so that hydrologic properties are significantly different in one versus the other, if the time of concentration exceeds 60 minutes, or if stonnwater runoff volume is an impottant factor. The combination of Rational Method hydrographs based on timing is prohibited.
( v) For comparison·of peak flow rates, flows shall be rounded to a tenth of a cubic foot per second (cfs).
(6) Routing of hydrographs tlu·ough detention/retention facilities for the pmpose of designing those facilities shall be accomplished using the Modified-Puis Method or other recognized reservoir routing method subject to Township's approval.
(7) HEC-HMS Model Calibrated and/or SWMM modeling is acceptable.
(8) The Township may require that computed existing runoff rates be reconciled with field observations, conditions and site history. If the designer can substantiate, tluough actual physical calibration, that more appropriate runoff and time of concentration values should be utilized at a particular site, then appropriate variations may be made upon review and recommendation of the Township.
(9) Runoff Coefficients.
( i) Rational Method (as authorized)- Use Table D-1 (Appendix D)
(ii) NRCS Rainfall-RunoffMethod- Use Table D-2 (Appendix D). Curve Numbers (CN) should be rounded to tenths for use in hydrologic models as they are a design tool with statistical variability. For large sites, CNs should realistically be rounded to the nearest whole number.
( 10) Time of Concentration.
( i) The Time of Concentration is to represent the average condition that best reflects the hydrologic response of the area. The following Time of Concentration (T.) computational methodologies shall be used unless another method is pre-approved by the Township:
(a) Pre-development - NRCS's Lag Equation:
Time of Concentration = T. = [(T,./6) * 60] (minutes)
(s + 1 )o .7 Tlag 1900 ff
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Where: T,.8 =Lag time (hours) L =Hydraulic length of watershed (feet) Y = Average overland slope of watershed (percent) S =Maximum retention in watershed as defined by: S = [(1000/CN)- 10) CN = NRCS Curve Number for watershed
(b) Post-development commercial, industrial or other areas with large impervious areas (> 20% impervious area) - NRCS Segmental Method. The length of sheet flow shall be limited to 100 feet. Tc for channel and pipe flow shall be computed using Manning's equation.
(ii) Additionally, the following provisions shall apply to calculations for Time of Concentration:
(a) The post-development Tc shall never be greater than the pre development Tc for any watershed or sub-watershed. This includes when the designer bas specifically used swales to reduce flow velocities. In the event that the designer believes that the post development Tc is greater, it will still be set by default equal to the pre-development Tc for modeling purposes.
(b) The minimum Tc for any watershed shall be 5 minutes.
(c) The designer must provide computations for all pre-development T. paths. A 5 minute Tc cannot be assumed for pre-development.
(d) Undetained fringe areas (areas that are not h·ibutary to a stormwater facility but where a reasonable effort has been made to convey rw10ff from all new impervious coverage to best management practices) may be assumed to represent the pre-development conditions for purposes ofT. calculation.
3.02.3 Predevelopment Conditions: Predevelopment conditions shall be assumed to be those which existed on any site at the time prior to the commencement of any development activities. Where a site has been developed previously and is proposed to be redeveloped, the predevelopment coefficient for the developed portion of the site shall be based upon an assumed fifty percent (50%) native land cover (i.e., grass, h·ees, etc.) and fifty percent (50%) developed land cover (e.g., buildings, pavement, etc.).
(1) NRCS runoff curve numbers selected for use in the calculations shall accurately reflect existing conditions subject to the approval of the Township.
(2) Hydrologic conditions for all areas with pervious cover (i.e., fields, woods, lawn areas, pastures, cropland, etc.) shall be assumed to be in "good" condition, and the lowest recommended NRCS runoff curve number (CN) shall be applied for all pervious land uses within the respective range for each land use and hydrologic soil group.
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3.02.4 Release Rate.
(1) Definition: The release rate percentage defines the percentage of the pre development peak rate of runoff that can be discharged from an outfall on the site after development under the 1-, 2-, 10-, 25- and 50-year storm conditions. Under all circumstances, a 100% release rate percentage shall be applied to the 100 year frequency storm whether or not lower reduced release rate percentages are specified for the 1-, 2-, 10-, 25 and 50-year retum frequency storms. The assigned release rate percentage for each subarea applies uniformly to all land development or alterations within the subarea. A listing of the release rate percentage by subarea appears in Appendix A of this Ordinance; the subareas are delineated on the Release Rate Percentage Map attached hereto and made a part ofAppendix A. This Appendix was established under the County of Erie's 1996 Act 167 Plan and is being retained to better protect the public health and safety.
(2) Procedure for Use.
( i) Identify the specific subarea in which the development site is located from the watershed map and obtaitr the subarea release rate percentage from the information in Appendix A.
(ii) Compute the pre-and post-developmentrunoffhydrographs for each stonnwater . outfall on the development site using an acceptable calculation method for the 1-, 2-, 10-, 25-, 50- and 100-year storms. Apply no on-site detention for stormwater management but include any techniques to minimize impervious surfaces and/or increase the time of concentration for stormwater runoffflowing from the development site.
(iii) Ifthe post-development peak mnoff rate is greater than the predevelopment peak runoffrate, or if such runoff exceeds release rates established in this Ordinance, then stormwater detention shall be required. The capacity of the detention facility shall be calculated by multiplying the predevelopment rate of runoff from the 1-, 2-, 10-, 25- and 50-year frequency stmm by the subarea release rate percentage and the predevelopment runoff rate from the 100- year stonn event by 100% to dete1mine the maximum allowable releases from any detention basin.
3.02.5 Exception Areas
(1) Exceptions to the peak discharge standards will be considered only in the following instances:
( i) In the Lake Erie Area Watershed: only in instances where the discharge from the development site occurs directly to Lake Erie, an adequately sized storm or combined sewer which discharges directly into Lake Erie, or through a properly sized and designed regional stormwater detention facility.
(ii) The analyses of storm or combined sewers and/or regional detention facilities as are necessary to demonstrate their adequacy for the proposed discharges shall be completed by the applicant using methods and procedures as directed by the Township.
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3.03 -Application of Standards
3.03.1 No exemption shall be allowed as to an Applicant's obligation to implement such measures as are necessary to: (1) Meet State Water Quality Standards and Requirements; (2) Protect health, safety and property; and.(3) Meet special requirements for High Quality (HQ) and Exceptional Value (EV) watersheds.
3.03.2 The Applicant must utilize the following BMPs to the maximum extent practicable to receive consideration for 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.
(6) Direct runoff to pervious areas.
3.03 .3 The Applicant's proposed development/additional impervious area may not adversely affect:
(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.
(6) Downstream property owners.
3.03 .4 An Applicant proposing Regulated Activities, after demonstrating compliance with Sections 3.03.1, 303.2 and 3.03.3, may be exempted from various requirements of this Ordinance if documentation can be provided that a downstream man-made water body (i.e., reservoir, lake, man-made wetlands or other BMP) has been designed or modified to address the potential stormwater flooding and volume impacts of the proposed development.
3.03.5 The purpose of this Section is to ensure consistency of storrnwater management planning between this Ordinance and NPDES permitting (when required) and to ensure that the Applicant has a single and clear set of st01mwater management standards to which the Applicant is subject. The Township may accept alternative stormwater management controls under this Section, provided that the Township, in consultation with the PaDEP, detennines that meeting the Volume Control requirements (see Section 3.02) is not possible or places an undue hardship on the Applicant.
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3.04 - Volume Controls
3.04.1 The Low hnpact Development Practices provided in the BMP Manual shall be utilized for all Regulated Activities to the maximum extent possible.
3.04.2 St01mwater runoff volume controls shall be implemented using the Design Sto1m Method or the Simplified Method as defined below. For Regulated Activity areas equal to or less than one (1) acre that do not require hydrologic routing to design the st01mwater facilities, this Ordinance establishes no preference for either method; therefore, an Applicant may select either method. The Simplified Method is authorized only where Regulated Activities involve no more than 1 acre and where the project does not require detailed design of stormwater management facilities.
3.04.3 The Design StonnMethod (CG-1) in the BMP Manual) is applicable to any sized Regulated Activity. This method requires detailed modeling based on site conditions.
(1) Do not increase the post-development total runoff volume for all storms equal or less than the 2-year, 24-hour storm.
(2) For hydrological modeling purposes:
( i) Existing non-forested pervious areas must be considered meadow (good condition) for pre-developed hydrological calculations.
(ii) Where any portion of the site has been developed previously, Pre-Development Conditions shall be determined as required in Section 3.02.3, above.
3.04.4 When allowed, the Simplified Method (CG-2) in the BMP Manual) is independent of site conditions and should be used if the Design St01m Method is not followed. For new impervious surfaces:
( 1) S t01mwater facilities shall capture at least the first 2 inches of runoff from all new· impervious sm'faces.
(2) At least the first 1 inch of nmofffrom new impervious surfaces shall be permanently removed from the rm10ffflow (i.e., it shall not be released into the surface waters of the Commonwealth). Removal options include reuse, evaporation, transpiration and infiltration.
(3) Wherever possible, infiltration facilities should be designed to accommodate infiltration of the entire pe1manently removed runoff; however, in all cases, at least the first 0.5 inch of the permanently removed runoff should be infiltrated.
(4) Actual field infiltration tests at the location of the proposed elevation of the stonnwater BMPs are required. Infiltration tests shall be conducted in accordance with the BMP Manual. A minimum 48-hour notification of the Township shall be provided to allow witnessing of the testing.
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3.04.5 In cases where it is not possible or desirable to use infiltration-based best management practices to partially fulfill the requirements in either Sections 3.04.2-3.04.4, the following procedure shall be provided to allow witnessing of the testing:
(1) At a minimum, the following documentation shall be provided to justify the decision to reduce the use of infiltration BMPs:
( i) Description of and justification for field infiltration/permeability testing with respect to the type of test and test locations.
(ii) 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 substance elements (fragipans and other restrictive layers, geology, etc.) that influence the direction and rate of subsurface water movement.
(iii) 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.
(iv) The provided documentation must be signed and sealed by a professional engineer or a professional geologist.
( v) A professional opinion, stated under signature and seal of a professional engineer or a professional geologist, stating that the proposed ground water recharge is consistent with natural recharge, is r~asonable and is consistent with this Ordinance.
(2) The following water quality pollutant load reductions will be required for all disturbed areas within the proposed development:
Pollutant Load Units Required Reduction(%) Total Suspended Solids (TSS) Pounds 85 Total Phosphorus (TP) Pounds 85 Total Nitrate (N03) Pounds 50
(3) The performance criteria for water quality best management practices shall be determined from the Pennsylvania Stonnwater Best Management Practices Manual ("BMP Manual"), most current version.
3.04.6 The applicable worksheets from the BMP Manual must be used in calculations to establish Volume Control.
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3.05 - Rate Controls
On all lands within Millcreek Township, the post-development peak discharge rates shall be in accordance with the release rate map for the Lake Erie Watershed as set forth in Appendix A of this Ordinance. See also Section 3.02.4.
3.06 -Grading Plans Where Ordinance Not Applicable
In developments not subject to this Ordinance under Section 103, a grading plan must be submitted to and approved by the Township Engineer prior to issuance of any building or local street access pe1mit.
3.07 - Modification of Approved Plans Prohibited
No person shall modify or alter any approved and/or implemented stormwater management or grading plan without the prior approval of the Board of Supervisors. This prohibition shall extend to the developer and to all successors and assigns, including grantees, owners, lessees, occupants and their contractors and/or agents. Any violation of this Section shall be subject to the remedies and penalties set forth in Article 13 of this Ordinance.
ARTICLE 4 EROSION AND SEDIMENTATION CONTROLS
4.01 - Erosion and Sedimentation Control Requirements
4.01. 1 An erosion/sedimentation plan shall be prepared for each development site in accordance with the Pennsylvania Erosion/Sedimentation Regulations (25 PA Code, Chapter 102) and the standards and guidelines of the Erie County Conservation District.
4.01.2 Provisions of the Subdivision and Land Development Ordinance and/or Zoning Ordinance as pertain to the development, shall apply with respect to submission of and action upon grading plans.
4.01.3 Proposed Erosion and Sedimentation Control measures shall be submitted with the stonnwater management plan.
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ARTICLES DESIGN CRITERIA FOR STORMWATER MANAGEMENT CONTROLS
5.01 - General Criteria
5.0 1.1 Applicants may select runoff control techniq11es, or a combination of techniques, which are most suitable to control stormwater runoff from the development site. All controls shall be subject to approval of the Township Engineer or other engineer designated by the Board of Supervisors. The Engineer may request specific information on design and/or operating features of the proposed stonnwater controls in order to determine their suitability and adequacy in terms of the standards of this Ordinance.
5.01.2 The applicant should consider the effect of the proposed stormwater management techniques on any special soil conditions or geological hazards which may exist on the development site. In the event such conditions are identified on the site, the Township Engineer may require in-depth studies by a competent geotechnical engineer. Not all stormwater control methods may be advisable or allowable at a particular development site.
5.0 1.3 In developing a stormwater management plan for a particular site, stormwater controls shall be selected according to the following order of preference:
( 1) Minimization of impervious surfaces during site design
(2) Flow attenuation by use of open vegetated swales and natural depressions
(3) Stormwater detention/retention structures\
5.0 1.4 Infiltration practices shall be used to the extent practicable to reduce volume increases and promote groundwater recharge. A combination of successive practices may be used to achieve the applicable minimum control requirements. Justification shall be provided by the applicant for rejecting each of the preferred practices based on actual site conditions.
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5.02 - General Design Criteria for Stormwater Management and Drainage Facilities
5.02.1 Stormwater shall not be transferred from one watershed to another, unless (i) the watersheds are sub-watersheds of a common watershed whichjoil1 together within the perimeter of the property; (ii) the effect of the transfer does not alter the peak rate discharge onto adjacent lands; or (iii) permanent easements from the affected landowner(s) are provided and shall be recorded.
5.02.2 Consideration shall be given to the relationship of the subject property to the drainage pattern of the watershed. A concentrated discharge of stormwater to an adjacent property shall be within an existing watercourse or confined in an easement or returned to a pre development flow type condition.
5.02.3 Innovative st01mwater BMPs and recharge facilities are encouraged (e.g., rooftop storage, dry wells, cisterns, recreation area ponding, diversion structures, porous pavements, holding tanks, infiltration systems, in-line storage in st01m sewers, and grading patterns). They shall be located, designed, and constmcted in accordance with the latest technical guidance published by PADEP, provided they are accompanied by detailed engineering plans and· performance capabilities and supporting site specific soils, geology, runoffand groundwater and infiltration rate data to verify proposed designs. Additional guidance from other sources may be accepted at the discretion of the Township (a pre-application meeting is suggested).
5.02.4 All existing and natural watercourses, channels, drainage systems and areas ofsurface water concentration shall be maintained in their existing condition unless an alteration is approved by the appropriate regulatory agency.
5.02.5 The design of all stormwater management facilities shall incorporate sound engineering principles and practices. The Township shall reserve the right to disapprove any design that would result in the continuation or exacerbation of a documented adverse hydrologic or hydraulic condition within the watershed, as identified in the Plan.
5.02.6 The design and construction of multiple use stonnwater detention facilities are strongly encouraged. In addition to stormwater management, facilities should, where appropriate, allow for recreational uses including ballfields, play areas, picnic grounds, etc. Consultation with the Township and prior approval are required before design. Provision for pe1manent wet ponds with st01mwater management capabilities may also be appropriate.
(1) Multiple use basins should be constmcted so that potentially dangerous conditions are not created.
(2) Water quality basins or recharge basins that are designed for a slow release of water or other extended detention ponds are not permitted for recreational uses, unless the ponded areas are clearly separated and secure.
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5.03-Design Criteria for Infiltration Systems
5.03.1 Infiltration systems shall be sized and designed based upon local soil and ground water conditions.
5.03.2 The use of practical structural and non-structural BMPs is encouraged in the design of site drainage and infiltration systems and development of land. Design of such measures shall consider the limitations of the site's topography and soils, and shall identify tbe benefits of proposed measures and maintenance requirements. Technical requirements and limitations ofBMPs are provided in the BMP Manual.
5.03.3 Infiltration systems greater than three (3) feet deep shall be located at least ten feet (10') feet from basement walls.
5.03.4 Surface drainage inlets shall be fitted with sediment control devices.
5.03.5 Infiltration systems may not receive runoff until the entire drainage area to the system bas received final stabilization.
5.03.6 The stormwater infiltration facility design shall provide an overflow system with measures to provide a non-erosive velocity of flow along its length and at the outfall.
Section 5.04 -Design Criteria for Flow Attenuation Facilities
5.04.1 If flow attenuation facilities are employed to assist in the control ofpeak rates of discharge, their effects must be quantified using the SCS Technical Release (TR) 55 Urban Hydrology for Small Watersheds or other method approved by the Township. The effects of the flow attenuation facilities on travel time should be reflected in the calculations.
5.04.2 Flow attenuation facilities such as swales and natural depressions should be properly graded to ensure positive drainage and avoid prolonged ponding of water.
5.04.3 Swales shall be properly vegetatively stabilized or otherwise lined to prevent erosion.
5.04.4 Swales shall be designed according to the recommendations contained in the Pennsylvania Erosion and Sediment Pollution Control Manual and Section 5.06.3 of this Ordinance.
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5.05 -Design Criteria for Stormwater Detention Facilities
All stormwater management facilities shall meet the following general design requirements:
5.05.1 Ifdetention facilities are utilized for the development site, the facility(ies) shall be designed such that post-development peak nmoff rates from the developed site are controlled to those rates defmed by the subarea release rate percentage for the 1-, 2-, 10-,25-, 50-and 100-year storm frequencies/rainfall values.
5.05.2 All detention facilities shaH be equipped with outlet structures to provide discharge control for the six (6) designated storm frequencies. Provisions shall also be made to safely pass the post-development 100-year storm runoff without damaging or impairing the continued function of the facilities. Any st01mwater management facilities regulated by Pa DEP Chapter 105 regulations shaH be designed in accordance with those regulations.
5.05.3 Shared-storage facilities which provide detention of runofffor more than one development site within a single subarea are encouraged wherever feasible and provided such facilities meet the criteria contained in this section. In addition, tunoff from the development sites involved shall be conveyed to the facility in a manner that avoids adverse impacts (such as flooding or erosion) to channels and properties located between tbe development site and the shared-storage facilities.
5.05.4 Discharging stormwater off the property to an existing facility may require supporting calculations, including hydraulic grade line calculations, as deemed necessary by the Engineer, to prove the adequacy of the downstream facilities. The developer, subject to Township approval, may elect to upgrade downstream facilities so as to accommodate the generated runoff.
5 .05.5 A multi-stage outlet may be .used for detention basins in order to provide discharge control for different storm frequency events, provided that the siltation facility precedes stormwater entty into the detention basin or outlet structure.
5.05.6 Any detention system which requires a Dam Safety Pennit or a Water ObsttUction Permit from the PaDEP shall be designed consistent with the provisions of the Dam Safety and Encroachments Act and the PaDEP Chapter 105 rules and regulations.
5.05.7 Setback Regulations. Above-ground detention facilities shall constitute structures for purposes of application ofyard setback regulations established in the Zoning Ordinance, No. 2011-8 as amended. Said facilities shall comply with those setback regulations from sttuctures, adjacent parcels, streets, etc. established in the Zoning Ordinance, generally and as specifically provided in its Section 3.30. Subject to compliance with these setback regulations, a detention facility may be located within a required buffer area.
5.05.8 No outlet stlucture from a st01mwater management facility or swale shall discharge directly onto a Township street or a State highway without approval from the Township or PennDOT, as applicable.
5.05.9 The top, or toe, of any slope of stormwater management facilities shall be located a minimum of 20 feet from any property line.
5.05.10 Interior slopes of the basin shall not exceed 3:1.
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5.05.11 Exterior slopes of compacted soil shall not exceed 3: 1, and may be further reduced if the soil has unstable characteristics.
5.05.12 Bottoms of detention basins should be graded with sufficient slope (minimum of 2%) to provide positive surface drainage. A subdrainage system may be required depending on the location of the pond bottom relative to groundwater levels. Slopes of less than 2% may be approved by the Township if warranted by site specifics, provided that in such event, a subdrainage system must then be installed. Facilities designed as water quality/ infiltration BMPs may have a bottom slope of zero.
5.05.13 The minimum horizontal distance between any stormwater holding facility and a building or structure shall be 20 feet. The lowest floor elevation of any stmcture constructed immediately adjacent to a detention basin or other storm water management facility shall be a minimum of2 feet above the 100-year water surface elevation.
5.05.14 Stormwater management facility bottom (or surface of permanent pool) elevations must be greater than adj acent floodplain elevations (FEMA or HEC-RAS analysis). Ifno floodplain is defined, bottom elevations must be greater than existing ground elevations 50 feet from top of stream bank in the facilities' vicinity. ·
5.05.15 Basin outflow culverts discharging into floodplains must account for tailwater. Tailwater corresponding to the 100-year floodplain elevation must be used for all design storms, or the Applicant may elect to determine flood elevations of the adjacent watercourse for each design stonn. The floodplain is assumed to be 50 feet from top of stream bank in areas where a floodway is not designated, or no other evidence is provided.
5.05.16 The invert of all stormwater management facilities and underground infiltration/storage facilities shall be located a minimum of2 feet above the seasonal high groundwater table. The invert of stonnwater facilities may be lowered if adequate subsurface drainage is provided. Flows from underdrains need not be accounted for in volume o'r rate control calculations.
5.05.17 Whenevex possible the side slopes and basin shape shall be amenable to the natural topography. Vertical side slopes and rectangular basins shall be avoided whenever possible.
5.05.18 Impervious low-flow channels are not petmitted within stonnwater management facilities.
5.05.19 Unless specifically designed as a Volume Control or water quality facility, all stormwater management facilities must empty over a period of time not less than 24 hours and not more than 72 houxs from the end of the facility's inflow hydrograph. Infiltration tests performed at the facility locations and proposed basin bottom depths, in accordance with the BMP Manual, must support time-to-empty calculations if infiltration is a factor.
5.05.20 Energy dissipaters and/or level spreaders shall be installed at points where pipes or drainageways discharge to or from basins. Discharges to drainage swales shall be dissipated, or piped, to an acceptable point.
5.05.21 Landscaping and planting specifications must be provided for all stormwater management basins and be specific for each type of basin. Minimal maintenance, saturation-tolerant vegetation must be provided in basins designed as water quality/infiltration BMPs.
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5.05.22 Principal Outlet Structures: The primary outlet structure shall be designed to pass all design storms (up to and including the 1 00-year event) without discharging through the emergency spillway. All principal outlet structures shall:
(1) Be constructed of reinforced concrete or an altemative material approved by the Township. When approved for use, all metal risers shall:
( i) Be suitably coated to prevent corrosion.
(ii) Have a concrete base attached with a watertight connection. The base shall be sufficient weight to prevent flotation of the riser.
(iii) Provide a trash rack or similar appurtenance to prevent debris from entering the riser.
(iv) Provide an anti-vortex device, consisting of a thin vettical plate normal to the basin benn.
(2) Provide trash racks to prevent clogging of primary outflow stmcture stages for all orifices.
(3) Provide outlet aprons and shall extend to the toe of the basin slope at a minimum.
5.05.23 Emergency Spillways: Any stormwater management facility designed to store runoff shall provide an emergency spill way designed to convey the 100-year post-development peak rate flow with a blocked primary outlet structme. The emergency spillway shall be designed per the following requirements:
( 1) The top of embankment elevation shall provide a minimum 1 foot offreeboard above the maximum water surface elevation. This is to be calculated when the spillway functions for the 100-year post-development inflow, with a blocked outlet structure.
(2) Avoid locating on fill areas whenever possible.
(3) The spillway shall be armored to prevent erosion during the 100-year post development flow, with a blocked primary outlet structure.
( i) Synthetic liners or riprap may be used, and calculations sufficient to support proposed armor must be provided.
(ii) An earthen plug must be used to accurately control the spillway invert if riprap is the proposed annoring material.
(iii) Emergency spillway armor must extend up the sides of the spillway, and continue at full width to a minimum of 10 feet past the toe of slope.
(4) Millcreek may require use of additional protection when slopes exceed 4:1 and spillway velocities might exceed NRCS standards for the particular soiJs involved.
(5) Any underground management facility (pipe storage system) must have a method to bypass flows higher than the required design (up to a 100-year post-development inflow) without structural failure, or causing downstream harm or safety risks.
(6) To the extent this Subsection conflicts with PPIC Figure SD-1 0, this Subsection shall control.
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5. 05.24 Design ofstonnwater management facilities having 3 feet or more ofwater depth (measured vettically from the lowest elevation in the facility to the crest of the emergency spillway) shall meet the following additional requirements:
(1) The maximum water depth within any stonnwater management facility shall be no . greater than 8 feet when functioning through the primary outlet structure.
(2) The top of embanlanent width shall be:
( i) For embanlanents up to 4', width shall be at least 6 feet;
(ii) For embanlanents between 4' and 6', width shall be at least 8 feet;
(iii) For embanlanents over 6', width shall be at least 10 feet.
(3) A 10'-wide access to the basin bottom must be provided with a maximum longitudinal slope of 10%.
(4) Berms shall be constmcted using soils that conform to the unified soil classification of(:H, MI-l, CL or ML. Soils used shall be tested to determine their density analysis per ASTM 698. The embanlanents shall be constructed in a maximum of 6 inch lifts. The lifts will each be compacted to a density at least 98% of their maximum dry density. Each layer of compacted fill shall be tested to determine its density per ASTM 2922 or ASTM 3017. One test per 50 cubic yards of material placed (at least one per layer) shall be performed by an independent testing agency.
(5) A cutoff and key trench of impervious material shall be provided under all embanlanents 4 feet or greater in height. The cutoff trench shall run the entire length of the embanlanent and tie into undisturbed natural ground.
(6) Anti-seep collars, or a PaDEP-approved alternative, must be provided on all outflow culverts in accordance with the methodology contained in the latest edition of the PaDEP E & S Control Manual. An increase in seepage length of 15% must be used in accordance with the requirements for permanent anti-seep collars.
5.05.25 To provide an access point fi:om which a detention facility can be maintained, a minimum 24"-d.iameter access point must be provided on all sides of an underground detention facility's ends. See also Section 5.02.6.3 of the Public and Private Improvements Code re. manway access ports or structures.
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5.05.26 Other considerations to be incorporated into the design of the detention facilities include:
(1) Inflow and outflow structures shall be designed and installed to prevent erosion and bottoms of impoundment type structures should be protected from soil erosion.
(2) Control and removal of debris both in the storage structure and in all inlet or outlet devices shall be a design consideration.
(3) Inflow and outflow structures, pumping stations, and other structures shall be designed and protected to minimize safety hazards.
( 4) The water depth at the perimeter of a storage pond should be limited to that which is safe for children. Restriction of access (fence, walls, etc.) may be necessary depending on the location of the facility and the maximum depths of water.
(5) Landscaping shall be provided for the facility which harmonizes with the surrounding area. Landscaping proposals, including type of vegetative cover, seeding and fertilizer rates, shall be submitted to the Engineer for approval. Landscaping shall not be considered complete until there is a minimum of 85% fully established vegetative cover.
(6) Facilities shall be located to facilitate maintenance, considering the frequency and type of equipment that will be required.
(7) Fencing shall be provided ifrequired by the Township. Factors to be considered.shall include but not be limited to depth and/or slope, whether the facility is to be used as an erosion and sedimentation control basin and/or the length of time water is likely to remain in the basin after a flood event.
5.05.27 Construction of Stonnwater Management Facilities.
(1) Basins used for rate control only shall be installed prior to or concurrent with any earthmoving or land disturbances, which they will serve. The phasing of their construction shall be noted in the narrative and on the plan.
(2) Basins that include water quality or recharge components shall have those components installed in such a manner as to not disturb or diminish their effectiveness.
(3) Compaction test reports shall be kept on file at the site and be subject to review at all times with copies being forwarded to the Township upon request.
(4) Temporary and permanent grasses or stabilization measures shall be established on the sides and base of all earthen basins within 15 days of construction.
5.05.28 Exceptions to these requirements may be made at the discretion of the Township for BMPs that retain or detain water, but are of a much smaller scale than traditional stonnwater management facilities.
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5.06 -Design Criteria for Collection!<;onveyance Facilities
5.06.1 All stormwater runoff collection or conveyance facilities, whether storm sewers or other open or closed facilities, shall be designed in accordance with the following basic standards:
(1) All storm sewer pipes, grass waterways, open channels, swales and other storm water canying or conveyance facilities that service drainage areas within the site must be able to convey post-development runoff from the 25-year design st01m.
(2) Stonnwater management facilities that convey off-site water through the site shall be designed to convey the 25-year stonn event (or larger events, as determined by the Township).
(3) All developments shall include provisions that allow for the overland conveyance and flow of the post-development 100-year stonn event without damage to public or private property.
(4) All sites shall be graded to provide drainage away from and around the structure(s) and improvements in order to prevent any potential flooding damage.
(5) The developer shall be responsible for extending roof, sump and French drains to a stormwater collection or conveyance control system, a storm sewer or a natural watercourse in accordance with the approvedstormwater management or grading plan for the development. Subject to these considerations:
( i) Roof drains and downspouts may discharge to a lawn area subject to Township approval; provided, that any discharge to a lawn area will be authorized only where it will not result in discharge of st01mwater onto neighboring properties and the owner of the subject property will be responsible for its maintenance.
(ii) Slope, soil type and distance from neighboring properties will be factors in the Township's considerations.
(iii) In appropriate circumstances, the Township may authorize connection ofa sump or a French drain to a dry well instead of to a storm sewer.
(6) Collection/conveyance facilities should not be installed parallel and close to the top or bottom of a major embankment to avoid the possibility of failing or causing the embankment to fail.
(7) All collection and conveyance facilities shall be designed to convey post development runoff without surcharging inlets for the 25-year storm event.
(8) Where drainage swales or open channels are used, they shall be. suitably lined to prevent erosion and designed to avoid excessive velocities.
(9) Within a delineated bluff recession hazard area, special care should be taken to properly direct, collect and discharge stonnwater mnoff so as to protect against bluff recession and erosion. The Developer's activities shall be coordinated with the Township to effect such protections.
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5.06.2 Storm Sewers. Storm sewers shall comply with the following criteria:
(1) Where practical, storm sewers shall be designed to traverse under seeded and planted areas. If constructed within 10 feet of road paving, walks or other surfaced areas, drains shall have a narrow h·ench and maximum compaction of backfill to prevent settlement of the superimposed surface or development; provided, that such backfill shall be required in the area within 5 feet of road paving in all cases and in the area within 10 feet of road paving where the h·ench depth is in excess of5 feet. See Figure SD-1 of the Public and Private Improvements Code for detail.
(2) Shall be installed after excavating and filling in the area to be traversed is completed, unless the drain is installed in the original ground with a minimum of 3 feet cover and/or adequate protection during the fill construction.
(3) Designed: (1) with cradle when traversing fill areas of indeterminate stability, (2) with anchors when gradient exceeds twenty percent (20%), and (3) with encasement or special backfill requirements when h·aversing under a paved area.
(4) Designed to adequately handle the anticipated stonnwater flow and be economical to construct and maintain. The minimum pipe size shall be I 2 inches in diameter.
(i) Minimum pipe size of 4 inches in diameter at a minimum slope of 0.5% will be allowed for conveyance of downspout flows from roof areas not exceeding 900 square feet.
(5) Drain pipe, trenching, bedding and backfilling requirements shall conform to Township specifications set f01th in the PPIC and shall be installed in such manner as is required in the PPIC and/or the Subdivision and Land Development Ordinance.
(6) Inlets, manholes, pipes and culve1ts shall be constructed in accordance with standards therefor in the PPIC and/or ilie Subdivision and Land Development Ordinance or, if not provided for therein, as set forth in PennDOT's Publication 408 and/or Publication 72M or other detail approved by the Township.
(7) Storm inlets and structures shall be designed to be adequate, safe, self-cleaning and unobtrusive and consistent wiili the Township's standards.
(8) Approved grates shall be designed for all catch basins, stormwater inlets and other entrance appurtenances.
(9) Manholes shall be designed so that the top shall be at finished grade and sloped to conform to the slope ofthe finished grade. Top castings of structures located in roads or parking areas shall be machined or installed to preclude "rattling."
(I 0) Storm sewer outfalls shall be equipped with energy dissipation devices to prevent erosion and conform with requirements of PaDEP's Chapter 105 regulations for stream encroachments.
(11) Where a proposed st01m conveyance system will connect with an existing conveyance system, the applicant shall demonstrate that sufficient capacity exists in the downsh·eam system to handle the increased volume of flows subject to the applicable release rate for peak flows.
(12) Catch basins shall be spaced at appropriate locations so that a spread of no more than ten feet (1 0') will occur during the design storm.
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(13) For inlets containing a change in pipe size, the elevation for the crown of the pipes shall be the same or the smaller pipe's crown and shall be at a higher elevation.
(14) At all street low points, swales and easements shall be provided behind the curb or swale and through adjacent properties to channelize and direct any overflow of stormwater runoff away from dwellings and structures.
(15) All inlets in paved areas shall have heavy duty bicycle safe grating. A note to this effect shall be added to the SWM Site Plan or inlet details in the Plan.
(16) Inlets must be sized to accept the specified pipe sizes without knocking out any of the inlet corners. All pipes entering or exiting inlets shall be cut flush with the inside wall of the inlet. A note to this effect shall be added to the SWM Site Plan or inlet details in the Plan.
(17) Inlets shall have weep holes covered with geotextile fabric placed at appropriate elevations to completely drain the subgrade prior to placing the base and surface course on roadways.
(18) Inlets,junction boxes or manholes greater than 5 feet in depth shall be equipped with ladder rungs and shall be detailed on the SWM Plan.
(19) Accessible drainage structures shall be located on continuous storm sewer systems at all vertical dislocations, at all locations where a transition in stonn sewer pipe sizing is required, at all ve1tical and horizontal angle points exceeding 5 degrees and at all points of convergence of two or more storm sewer pipes.
(20) All storm drainage piping shall be provided with either reinforced concrete headwalls or end sections of compatible material as the pipe involved at its entrance and discharge.
(21) Stonnwater roof drains and pipes shall not discharge onto impervious areas or be connected to stonn sewers without approval by the Township.
(22) Inlets shall have a 6 inch sump in the bottom.
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5.06.3 Swale Conveyance Facilities.
(1) Swales must be able to convey post-development runoff from a 25-year design storm with 6 inches offreeboard to top of the swale and side slopes no steeper than 3:1.
(2) All swales shall be designed, labeled on the SWM Plan with details provided in the SWM Plan to adequately construct and maintain the design dimension of the swales.
(3) Swales shall be designed for stability using velocity or shear criteria. Velocity criteria may be used for channels with less than 10% slope. Shear criteria may be used for all swales. Documentation must be provided to support velocity and/or shear limitations used in calculations.
(4) Where swale bends occur, the computed velocities or shear stresses shall be multiplied by the following factor in determining design of swale erosion protection:
( i) 1.75 -When swale bend is 30 to 60 degrees.
(ii) 2.00- When swale bend is 60 to 90 degrees.
(iii) 2.50 -~hen swale bend is 90 degrees or greater.
(5) Manning's "n" values used for swale capacity design must reflect the permanent condition.
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ARTICLE6 SWM SITE PLAN AND REPORT REQUIREMENTS
6.01 - Genenl Requirements
For any of the activities regulated by tllis Ordinance and not eligible for the exemptions provided in Section 6.02, no final subdivision/land development plan shall be approved, no pernlit authorizing construction shall be issued, or an earth moving or land disturbance activity initiated until the Applicant has received written approval from the Township of the final Stormwater Management Site Plan ("SWM Site Plan") for the site.
6.02 - General Exemptions
The following activities are specifically exempt from the SWM Site Plan and Report preparation provisions of this Ordinance unless tl1e Township determines that tile activity is likely to, has, or will negatively impact the purposes and objectives set forth in Article 1. For example, where an activity occurs on very steep tenain or where an activity is the latest in a series of incremental developments expected to cause pronounced stormwater impacts, it may be that these activities will be required to comply with the plan preparation requirements contained herein even though their activities qualify under the listing in this section. Upon making such deternlination, the Township shall give notice in writing to the Applicant and direct the Applicant to immediately cease and desist all activity and affirmatively comply with the formal plan, subnlission, and approval procedures of this ordinance. Exemption shall not relieve the applicant from providing adequate stonnwater management to meet the purpose of this Ordinance.
6.02.1 Any Regulated Activity that would create 5,000 square feet or less of impervious area; provided, however, that the Township may require plan preparation for developments . creating in excess of 1,500 square feet of impervious area if drainage or stormwater management problems exist upon the subject premises or upon properties adjacent to it. This criteria shall apply to the total Site even if development is to take place in phases. Impervious cover shall include, but not be limited to, any roof, parking or driveway areas and any new streets and sidewalks. Any areas designed to initially be gravel or crushed stone shall be assumed to be impervious for the purposes of this exemption criteria.
(1) An Applicant proposing Regulated Activities, after demonstrating compliance with Section 3.03 and iliis Section, may be exempted from various requirements of this Ordinance according to the following table:
New Impervious Al·ea 1 (square footage) Applicant Must Provide 0 - 1,000 1,000- 1,500 Documentation of impervious area 1,500- 5,000 Volume Controls and Simplified Method or Small Project SWM Application > 5,000 Rate & Volume Controls, SWM Site Plan
NOTE: I Gravel in existing condition shall be considered pervious. Gravel in proposed condition shall be considered impervious.
(2) The exemption set forth above shall be cumulative, and all development activity within a five (5)-year period shall be included within calculations.
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(3) A Small Project Stormwater Management Application (on a fo1m adopted by the Township) may be used for projects under 5,000 square feet of new impervious surface and single family residential home construction, where soils on the site are entirely Type A, B and/or C. The Small Project SWM Application allows documentation of new impervious smface, credits through disconnection of impervious surfaces and tree planting, and sizing of Volume Control BMPs that may be required.
(4) Alternatively or where TypeD soils are present on the site, general standards for regulated activities creating 5,000 square feet or less of impervious area, in the aggregate under the Simplified Method, are as set forth on Appendix C to tbis Ordinance. Except for circumstances in which the Township requires a SWM Site Plan and Report, the Simplified Method will be available for use regardless of soil type.
6.02.2 Use of land for gardening for home consumption.
6.02.3 Agricu.ltme when operated in accordance with a conservation plan or erosion and sedimentation control plan prepared by the County Conservation District. The agricultural activities such as growing crops, rotating crops, filling of soil and grazing animals and other such activities are specifically exempt from complying with the requirements of this Ordinance when such activities are conducted in accordance with a conservation plan prepared by the County Conservation District. The construction of buildings, parking lots or any activity that may result in impervious surface which increases the rate and volume of stormwater runoff shall comply with the requirements of this Ordinance.
6.02.4 Forest management and timber operations are exempt from the Rate and Volume Control requirement and SWM Site Plan preparation requirement of this Ordinance provided that such activities are performed according to the requirements of25 Pa. Code Chapter 102. Temporary roadways are not exempt.
6.02.5 The Township may deny or revoke any exemption pursuant to this Section at any time for any project which the Township believes may pose a threat to public health, public safety, property or the environment.
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6.03 - SWM Site Plan and Report Contents
The SWM Site Plan and SWM Site Report shall consist of all applicable calculations, maps and plans. All SWM Site Plan materials shall be submitted to the Township in a format that is clear, concise, legible, neat and well-organized. Otherwise, the SWM Site Plan shall be rejected.
Appropriate provisions from Millcreek's Subdivision and Land Development and Zoning Ordinances, PPIC and other applicable regulations shall be followed in preparing the SWM Site Plan.
6.03.1 The SWM Site Plan shall include, but not be limited to:
(1) Plans, which shall be of one size and in a form that meets the requirements for recording in the office of the Erie County Recorder of Deeds.
( i) Plans for tracts of less than 20 acres shall be drawn to a scale of one inch equals no more than 50 feet;
(ii) Plans for tracts of20 acres or more shall be drawn to a scale of one inch equals no more than 100 feet;
(iii) All lettering shall be drawn to a size to be legible if the plans are reduced to half size.
(2) General Format. All shall contain a title block setting forth: Name and location address of the property site, name, address and telephone number of the Applicant/Owner of the property, name, address, telephone number, email address and engineering seal of the professional engineer responsible for the SWM Site PIan.
(3) The date of submission and dates of all revisions.
(4) A graphical and written scale on all drawings and maps.
(5) A north arrow on all drawings and maps.
(6) A location map at a minimum scale.
(7) Existing and Proposed Features: The plan shall show on separate drawings (one of Existing Conditions and the other ofProposed Conditions) the following under both pre-development and post-development conditions:
( i) A key map showing the location of the development site within the watershed(s) and watershed subarea(s). On all site drawings, show the boundaries of the watershed(s) and subarea(s) as they are located on the development site and identify watershed names(s) and subarea number(s).
(ii) A location map at a minimum scale of 1 inch equals 1,000 feet and which illustrates the project relative to streets and highways, municipalities or other identifiable landmarks.
(iii) Metes and bounds description of the entire tract perimeter.
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(8) Contours - Show existing and final contours at intervals of one (1) foot; in areas with slopes greater than fifteen (IS) percent, five (5) foot contour intervals may be used.
(9) Perimeters of a11 existing bodies of water (natural or artificial), watercourses (pennanent and intermittent), swales, wetlands and other natural drainage courses on the development site or which will be affected by runofffrom the development, areas of natural vegetation to be preserved, the total extent of the upstream area draining through the site and overland drainage paths. In addition, any areas necessary to detennine downstream impacts, where required for proposed stonnwatermanagement facilities, must be shown.
(10) Proposed impervious surfaces (structures, roads, paved areas and buildings), including plans and profiles ofroads and paved areas and floor elevation ofbuildings.
(I I) Soils-Provide an overlay showing soil types and boundaries within the development site (consult County, SCS and U.S. Geological Survey for information).
(12) A key map showing all existing man-made features beyond the property boundary that may be affected by the project.
(13) The location and clear identification of the nature ofpennanent st01mwater BMPs.
(I4) The location of all existing and proposed utilities, on-lot wastewater facilities, water supply wells, sanitary sewers and water lines, on and within fifty feet (50') of property lines, including inlets, manholes, valves, meters, poles, chambers, junction boxes and other utility system components.
(15) Land cover - Show existing and final land cover classifications as necessary to support and illustrate the runoff calculations performed; include proposed structures, roads, paved areas and buildings and areas of intended future expansion.
(16) Drainage area delineations - Show the boundaries of the drainage areas employed in the runoff calculations performed.
(I7) Stormwater management controls - Show any existing stormwater management or drainage controls and/or structures, such as storm sewers, swales, culverts, etc. which are located on the development site, or which are located off-site but will be affected by runoff from the development.
(18) Existing and proposed land uses.
(19) Horizontal alignment, vettical profiles and cross-sections ofall open channels, pipes, swales and other BMPs.
(20) Floodplain boundaries- Identify IOO-year floodplains on the development site (as appropriate) based on the Township's Flood Insurance Study maps.
(21) The location of all erosion and sedimentation control facilities, shown separately from the SWM Site Plan (typically, an E & S Control Plan).
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(22) Stormwater Controls: All proposed stonnwater lUnoff control measures must be shown on the plan including methods for collecting, conveying and storing stonnwater runoff on-site, which are to be used both during and after construction. Erosion and sedimentation controls shall be shown in accordance with Article 4 of this Ordinance. The Site Plan or the Report shall provide information on the exact type, location, sizing, design and construction of all proposed facilities and their relationship to the existing watershed drainage system. The Report shall include technical specifications for materials and methods to be used in the construction of the stormwater management facilities.
( i) If the development is to be constlUcted in stages, the applicant must demonstrate that stonnwater facilities will be installed to manage stormwater lUnoff safely during each stage of development.
(ii) A schedule for the installation of all temporary and permanent st01mwater control measures and devices shall be submitted.
(iii) If appropriate, a justification should be submitted as to why any preferred stormwater management techniques, as listed in Article 5 of this Ordinance, are not proposed for use.
(23) Easements, Right-of-Ways, Deed Restrictions: All existing and proposed easements and rights-of-way for drainage and/or access to st01mwater control facilities shall be shown along with any areas subject to special deed restrictions relative to or affecting st01mwater management on the development site.
(24) A minimum twenty foot (20')-wide access easement around all stormwater management facilities that would provide ingress to and egress from a public right of way. In lieu ofproviding an easement to the public right ofway , a note may be added to the plan, granting to the Township and to such person(s) or entity(ies) as will be responsible for future maintenance access to all easements via the nearest public right of way.
(25) Construction details for all drainage and stmmwater BMPs.
(26) Construction sequence.
(27) Identification of short-term and long-tetm ownership, operations and maintenance responsibilities.
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(28) Notes and Statements.
( i) A statement, signed by the landowner, acknowledging that the stmmwater BMPs are fixtures that cannot be altered or removed without prior approval by the Township.
(ii) A statement referencing the Operation and Maintenance (O&M) Agreement and stating that the O&M Agreement is part of the SWM Site Plan.
(iii) A note indicating that Record Drawings will be provided for all stormwater facilities prior to occupancy or the release of financial security.
(29) Required Signature Blocks
( i) The following signature block for the professional engineer in charge of preparing the Stormwater Management Plan:
"I, P.E., hereby certify that the Stonnwater Management Plan meets all design standards and criteria of the Millcreek Township Stonnwater Management Ordinance."
(ii) The following signature .block for the Township reviewing the Stormwater Management Plan, this to be signed by a professional engineer in the firm retained by the Township to review such plans:
"I, , P.E., have reviewed this Stormwater Management Plan in accordance with the Design Standards and Criteria of the Millcreek Township Stormwater Management Ordinance."
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6.03.2 The SWM Site Report shall include, but not be limited to:
(1) General data, including:
( i) Project name;
(ii) Project location address and Township and Erie County tax index numbers;
(iii) Name, address and telephone number of the Applicant/Owner of the propetty;
(iv) Name, address, telephone number, email address and engineering seal of the individual responsible for preparation of the SWM Site Report;
( v) Date of submission and revisions.
(2) Project description narrative which clearly discusses the project and provides the following information, where applicable:
( i) Narrative
Statement of the regulated activity, describing what is being proposed, overall stonnwater management concept with a description of permanent stormwater management teclmiques, including construction specifications and materials to be used for stormwater management facilities. Expected project schedule. Location map showing the project site and its location relative to release rate districts.
Detailed description of existing site conditions including a site evaluation completed for projects proposed in areas of carbonate geology or karst topography, and other environmentally sensitive areas such as brownfields.
Total site area -pre and post, which must be equal or have an explanation as to why it is not.
Total site impervious area. Total off-site areas. Number and description of stonnwater management facilities. Type of development. Pre-development land use. Whether the site is a water quality sensitive (WQS) development. Whether the site is in a defined sensitive area. Types of water quality and recharge systems used, if applicable. Complete hydrologic, hydraulic and structural components for all st01mwater management facilities.
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(ii) Ownership and Maintenance Detail
A written maintenance plan for all stormwater management features, including detention facilities and other stonnwater management elements.
Identification of ownership and maintenance responsibility for all permanent st01mwater management facilities (including name, address and telephone number of all persons or entities identified).
(iii) Summary Tables
Pre-development Hydrologic Soil Group (HSG) assumptions, curve numbers (CN), computation of average slope, hydraulic length, computed time concentration.
Existing conditions runoff volume and peak rate of runoff.
Post-development runoff volume and peak rate of runoff.
Undetained areas, areas to ponds.
Land use for each subarea.
Hydrologic soil group (HSG) assumptions, curve numbers (CN).
Time of concentration computed for each subarea.
Post-development peak rate of runoff routed to ponds and out.
Pond maximum return period design data, including maximum water surface elevation, berm elevation and emergency spillway elevation.
Water quality depth and volume requirements.
(iv) Calculations
Complete hydrologic, hydraulic and structural computations, calculations, assumptions and criteria for the design of all stormwater BMPs.
Details of the berm embankment and outlet structure, indicating the embankment's top elevation, side slopes and top width, emergency spillway elevation, perforated riser dimensions, pipe barrel dimensions and dimensions and spacing of antiseep collars.
Design computations for the control structures (pipe barrel and riser, etc.).
A plot or table of the stage-storage (volume vs. elevation) and all supporting computations.
Routing computatiOJ1S.
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( v) Drawings
Drainage area maps for all watersheds and inlets depicting the time of concentration path for both existing conditions and post-developed condition.
All stormwater management facilities must be located on a plan and described in detail, including easements and buffers boundaries.
(3) Description of,justificationand actual field results for infilh·ation testing with respect to the type oftest and test location for the design of infiltration BMPs.
(4) The effect of the project (in terms of runoff volumes, water quality and peak flows) on surrounding properties and aquatic features and on any existing municipal stormwater collection system that may receive runoff from the project site.
(5) Description of tbe proposed changes to the land surface and vegetative cover, including the type and amount of impervious area to be added.
(6) Identification ofshort-term and long-tenn operation and maintenance responsibilities as well as schedules and cosets for inspection and maintenance activities for each permanent stormwater or drainage BMP, including provisions for permanent access or maintenance easements.
(7) Runoff Calculations: Calculations for detennining pre- and post-development discharge rates and for designing proposed stormwater control facilities must be sub1nitted with the stormwater management plan. All calculations shall be prepared using the methods and data prescribed by Article 3 of this Ordinance.
· (8) Maintenance Program: The proposed maintenance plan for all stonnwater control facilities shall:
( i) Identify the proposed ownership entity (e.g., property owner, private corporation, homeowners' or unit owners' association, other entity).
(ii) Identify the type ofmaintenance, probable frequencies, personnel and equipment requirements and estimated annual maintenance costs (with substantiation ofthe estimate's basis).
(iii) Identify the method for financing the continuing operation and maintenance of the facility if the facility is to be owned by other than a governmental agency.
(iv) Include copies of any legal agreements required to implement the maintenance program and, if applicable, copies of the maintenance agreement as required under Alticle 9 oftbis Ordinance.
(9) Financial Guarantees: Submit financial guarantees in accordance with the provisions of Alticle 11 of this Ordinance.
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(10) Supplemental inf01mation to be provided prior to recording of the SWM Site Plan, as applicable:
( i) Other Permits/ Approvals: A list of any approvals/permits relative to stormwater management that will be required from other governmental agencies (e.g., PaDEP Chapter 105 and 106 permits and/or NPDES permit) and anticipated dates of submission/receipt should be included with the st01mwater plan submission. Copies of permit applications may be requested by the Township where they may be helpful for the plan review.
(ii) Signed and acknowledged Operations and Maintenance Agreement.
(iii) Signed and executed easements, as required for all on-site and off-site work.
(iv) Geologic Assessment.
( v) Soils investigation report, including boring logs, compaction requirements and recommendations for construction of detention basins.
(vi) A highway occupancy permit from PellllDOT when utilization of a PellllDOT drainage system is proposed or when proposed facilities would encroach onto a PennDOT right of way.
(vii) Notice to Downstream Municipality: To meet the Section 3.01.22 requirement, the developer, by certified mail, shall notify the municipality immediately downstream of the proposed development that a stormwater control plan has been prepared and submitted. This letter shall identify the location of the proposed development site and the name of the affected stream. Copies of this letter and of the certified mail return receipt shall be included in the Report.
6.03.3 Professional Certification: The principal in charge of preparing the SWM Site Plan and Report (including all calculations) shall be a registered professional engineer and the stormwater management plan shall be sealed by a registered professional engineer with training and expertise in hydrology and hydraulics. A professional engineer certifying a SWM Site Plan, Report and/or as-bui lt drawings shall maintain in force at all times professional liability or errors and omissions insurance coverage having limits of not less than $1,000,000.00. Documentation of qualifications and insurance coverage may be required by the Township.
6.04 - SWM Site Plan and Report Submission
6.04.1 The Applicant shall submit the SWM Site Plan and Report for the Regulated Activity(ies).
6.04.2 Sto1mwater plan applications shall be submitted with the preliminary and final subdivision/land development applications.
6.04.3 A minimum of three (3) copies of the SWM Site Plan and Report shall be submitted to the Township. The Board of Supervisors shall have authority, by resolution, to establish and amend the number of copies required. Additional copies shall be submitted as requested by the Township or PaDEP.
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ARTICLE-7 PLAN REVIEW PROCEDURES
7.01 -Pre-Application Phase
7.01.1 Before submitting the stormwater plan, applicants are urged to consult with the Township on the applicable regulations and teclmiques for safely managing runoff from the development site. The Township may also be helpful in providing necessary data for the stormwater management plan.
7.01.2 Applicants are encouraged to submit a sketch plan with a nanative description of the proposed stormwater management controls for general guidance and discussion with the Township and other agencies.
7.01.3 The pre-application phase is not mandatory. Any review comments provided by the Township are advisory only and do not constitute any legally binding action on the part of the Township.
7.02 - SWM Site Plan and Report Reviews
7.02.1 Notification ofAffected Municipalities: The developer is required to notify municipalities immediately downstream of the development site that a stormwater control plan bas been submitted. Copies of the plans will be made available to the municipalities upon request. Comments received from any affected municipality will be considered· by the Township engineer and county agencies in their reviews. Prior to first consideration of the plan or the development plan to which it pertains, the developer must submit to the Township Engineer proof that 1·equired notice to downstream municipalities has been given. See Section 6.03 .2( 1O)(vii).
7.02.2 Engineer's Review.
(1) Stormwater management plans submitted to the Township shall be referred to a consulting engineer to be selected by the Board of Supervisors for review of submitted plans and issuance ofw ritten reports and certifications required under this subsection, unless the Board of Supervisors upon approval of the first plan application should otherwise direct. Where plan applications and reports are referred to the retained finn, "Township engineer" shall mean the engineer or finn retained by the Township to review submitted plans and reports.
(2) The Township's engineer shall review the SWM Site Plan and Repmt for consistency with the purposes, requirements and intent of this Ordinance and recommend approval or disapproval of the stonnwater management plan based on the requirements of the Township's ordinances, the standards and criteria of the watershed plan and good engineering practice. The engineer shall submit a written report, along with supporting documentation, stating reasons for approval or disapproval.
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(3) All fees and costs associated with such reviews, inspections, administration, reports and related services shall be paid by the applicant and deemed plan application, review, inspection and administration fees. The Board of Supervisors shall by Resolution adopted from time to time establish a schedule of such fees and the manner of their prepayment by the applicant. All such fees shall be paid or deposited prior to recordation of the subdivision or land development plat to which it pertains.
(4) The Board of Supervisors by Resolution shall establish procedures and policies governing such reviews, which shall address prohibitions against conflicts ofinterest, identify those engineers eligible for refenals and establish the process for refenal of proposed plans to an engineer retained by the Township.
(5) Permits Required from Other Governmental Agencies: Where the proposed development requires an obstruction permit from the Pennsylvania DEP or an erosion/sedimentation permit from the County Conservation District, final stormwater management plan approval shall be granted subject to the receipt ofsuch permits. No building permit shall be issued, nor construction started, until the permits are received and copies filed with the Township.
(6) The Township shall not approve any SWM Site Plan and Report that is deficient in meeting the requirements of this Ordinance. At its sole discretion and in accordance with this Article, when a SWM Site Plan and Rep01t is found to be deficient, the Township may disapprove the submission and require aresubmission, or in the case of minor deficiencies, the Township may accept submission of modifications.
(7) The Township shall notify the Applicant in writing within 45 calendar days after the Township Engineer's receipt of a complete SWM Site Plan and Report whether the SWM Site Plan and Repott is approved or disapproved if the SWM Site Plan and Report is not part of a subdivision or land development plan. Computation of review time shall not commence until the day on which a complete SWM Site Plan and Report meeting requirements of Article 6 have been submitted.
7.02.3 Engineering Certification: The engineer reviewing stormwater management applications and submitting recommendations thereon to the Board of Supervisors shall certify that any application recommended for approval meets all requirements of the Stonnwater Management Act, this Ordinance and other applicable laws, ordinances and regulations. If a review indicates that all requirements have not been met, the engineer shall in writing identify deficiencies and recommend the corrective measures needed to ensure compliance.
7.02.4 Approvals Conditioned on SWM Site Plan and Report Approval. The Township shall not issue a zoning, construction or other permit for any Regulated Activity, nor shall it allow recordation of any approved subdivision, land development or other plan until the Township's Engineer has issued its written certification that the submitted SWM Site Plan and Report meet all requirements ofthis Ordinance. All required permits from PaDEP must have been obtained prior to issuance of a Township zoning or construction permit. See also Section 9.03.4 pertaining to recording of documents after approval.
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7.03 -Modification of Plans
7.03.1 A modification to a submitted SWM Site Plan and Report for a development site that involves a change in stormwater management facilities or techniques, or that involves the relocation or redesign of stormwater management facilities, or that is necessary because soil or other conditions are not as stated on the SWM Site Plan as determined by the Township, shall require a re-submission of the modified SWM Site Plan in accordance with this Ordinance.
7.03.2 If the request for a plan modification is initiated before construction begins, the SWM Site Plan and Report must be resubmitted and reviewed according to the procedures contained in this Article.
7.03.3 If the request for a plan modification is initiated after construction is underway, the engineer who reviewed the original plan shall recommend approval or disapproval of the modification based on field inspection provided: (1) the r~quested changes in stonnwater controls do not result in any modifications to other approved Township land use/development requiJements (e.g., building setbacks, yards, etc.) and (2) the performance standards in Article 3 of this Ordinance are met. Notification of the engineer's action shall be sent to the Board of Supervisors, which may issue a stay of the plan modification within fomteen (14) days and require the permittee to resubmit the plan modification for full stormwater plan review in accordance with the procedures contained in this Article.
7.03.4 The applicant shall be responsible for payment of all fees and costs incurred as a consequence of review, approval and/or inspection of a plan modification.
7.04 - Resubmission of Disapproved SWM Site Plan and Report
7 .04.1 A disapproved SWM Site Plan and Repmt may be resubmitted with the revisions addressing the Township's concerns documented in writing to the Township in accordance with this Ordinance.
7.04.2 The applicable Review Fee must accompany a resubmission of a disapproved SWM Site Plan and Report.
7.05- Authorization to Construct and Term of Validity
7.05.1 Upon final stotmwater plan approval, receipt of all necessary permits, and recording of the final subdivision or land development plan in the Erie County Recorder ofDeeds Office, the applicant may commence to install or implement the approved stormwater management controls and engage in the Regulated Activities contained in the SWM Site Plan.
7.05.2 The Township's approval of a SWM Site Plan and Report authorizes the Regulated Activities contained in the SWM Site Plan for a period of five (5) years following the date of approval (the date the Township signs the approval for the SWM Site Plan); provided that:
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( 1) If site development or building construction does not begin within two years of the date of final approval of the SWM Site Plan and Rep011, then before doing so, the applicant shall resubmit the SWM Site Plan and Report to verify that no condition has changed within the watershed that would affect the feasibility or effectiveness of the previously approved st01mwater management controls.
(2) Iffor any reason development activities are suspended for two years or more, then the same requirement for resubmission of the stormwater management plan shall apply.
(3) If stormwater management facilities included in the approved SWM Site Plan have not been constructed, or if a Record Drawing ofthese facilities has not been approved within five (5) years after the date of approval, then the Township shall consider the SWM Site Plan disapproved and shaH revoke any and all permits or approvals, without any prior notice to the Applicant being required.
(4) An Applicant's failure to commence and/or complete required activities within the time periods required in this Section shall constitute a default of said Applicant's obligations under Applicant's Developer's Agreement with the Township, and shall entitle the Township to exercise rights against financial security to secure completion of said improvements.
7.06 - Record Drawings, Completion Certificate and Final Inspection
7 .06.1 The Applicant shaH be responsible for providing Record Drawings of all stormwater BMPs included in the approved SWM Site Plan. The Record Drawing and an explanation of any discrepancies with the approved SWM Site Plan shall be submitted to the Township as a prerequisite for the release of financial security for completion of required improvements and/or issuance of an occupancy certificate.
7.06.2 The Record Drawing shall include a certification of completion signed by a professional engineer verifying that all permanent stormwater BMPs have been constructed according to the approved SWM Site Plan and Report.
(l) Drawings shall show all approved revisions and elevations and inverts to all manholes, inlets, pipes and stormwater control facilities.
(2) · Submission shall include a comparison of the constructed stage-storage (volume vs. elevation) of all above-ground and below-ground stonnwater storage facilities to the approved design.
(3) After receipt of the Record Drawing and certification ofcompletion by the Township, the Township shall conduct a fmal inspection.
7.07 -Import of Stormwater Management Plan
A stonnwater management plan is intended under this Ordinance as a developer's means of meeting the developer's obligations under the Stonnwater Management Act. Neither the Township's approval of a submitted submitted plan nor any subsequent acceptance of dedication shall relieve the developer of his/her/its obligation to control st01mwater from the development as is established in the Act.
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ARTICLE 8 EASEMENTS
8.01 - Easements Generally
8.01.1 Easements shall be established to accommodate the existence of drainageways.
8.01.2 Where a tract is traversed by a watercourse (e.g., drainage-way, channel or stream), there shall be provided an easement paralleling the line of such watercourse with a width adequate to preserve the unimpeded flow of natural drainage in the 100-year floodplain.
8.0 1.3 Easements shall be established for all on-site stonnwater management or drainage facilities, including but not limited to detention facilities (above- or below-ground), infiltration facilities, all stonnwater BMPs, drainage swales and drainage facilities (e.g., inlets, manholes, pipes, etc.).
8.0 1.4 Easements are required for all areas used for off-site stormwater control, and such easements should be perpetual and recorded as a condition of development plan approval.
8.0 1.5 All easements shall be a minimum of20 feet wide and shall encompass the 100-year surface elevation of the proposed stormwater facility.
8.01.6 Easements shall provide ingress to and egress from a public right of way. In lieu of providing an easement to the public right of way, a note may be added to the plan granting to the Township or its designees access to all easements via the nearest public right of way able for vehicle ingress and egress on grades of less than 10% for carrying out inspection or maintenance activities.
(1) Such easement shall also be granted in favor of any owners' association or other entity which will be responsible for maintenance of the facility upon its completion.
8.01.7 Where possible, easements shall be centered on side and/or rear lot lines.
8.0 1.8 Nothing shall be planted, placed or constructed within an easement premises which would adversely affect the function of the easement, conflict with any conditions associated with such easement and/or obstruct the free access to the premises by the grantees of such easement and/or their successors, contractors and assigns.
8.02 - Recording of Easement Interests
8.02.1 Easements may be established on a recorded development or other plan, so long as the owner clearly grants, dedicates or conveys such easement on the plan in tenns acceptable to the Township.
8.02.2 All easement agreements shall be recorded with a reference to the recorded easement agreement indicated on the site plan. Easement agreements shall refer clearly to the development to which they pertain and recording detail for such development plan. The format and content of the easement agreement shall be reviewed and approved by the Township and its Solicitor.
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ARTICLE9 MAINTENANCE OF STORMWATER MANAGEMENT CONTROLS
9.01 - Maintenance Responsibilities
9.01.1 The SWM Site Plan and Report for the project site shall describe the future operation and maintenance responsibilities. The operation and maintenance description shall outline required routine maintenance actions and schedules necessary to ensure proper operation of the stonnwater control facilities. ·
9.01.2 The SWM Site Plan and Rep01t for the project site shall establish responsibilities for the continuing operation and maintenance of all proposed stormwater control facilities, consistent with the following principles:
(1) If a development consists of structures or lots which are to be separately owned and in which streets, sto1m sewers and other public improvements are to be dedicated to the Township, stormwater control facilities may be dedicated to and maintained by the Township, subject to approval of the Board of Supervisors.
(2) If a development site is to be maintained in single ownership or if storm sewers and other public improvements are to be privately owned and maintained, then the ownership and maintenance ofstormwater control facilities shall be the responsibility of the owner or private management entity.
(3) Millcreek Township will not agree to provide maintenance services for st01mwater management controls except as set forth in this Article.
(4) Millcreek Township prefers that stormwater detention facilities be owned and maintained by the developer or its assigns, including but not limited to property owners' associations established for the purpose of maintaining common facilities.
(5) Facilities, areas or structures used as stormwater BMPs shall be enumerated as permanent real estate appurtenances and recorded as deed restrictions or easements that run with the land.
(6) If an Applicant proposes that the Township accept ownership or maintenance responsibility of any stormwatermanagement facilities, Applicant's preliminary plan application or, if none, single final development plan application shall identify all facilities proposed to be dedicated to or maintained by the Township. The Township shall determine whether it agrees to assume any such responsibilities prior to commencement of review of the SWM Site Plan and Report.
(7) The SWM Site Plan and Report as approved by the Township shall be recorded as a restrictive deed covenant that nms with the land.
9.01.3 The Board of Supervisors, upon recommendation of the Township Engineer, shall make the final determination on the continuing maintenance responsibilities prior to final approval of the st01mwater management plan. The Board of Supervisors reserves the right to accept or reject the ownership and operating responsibility for any or all of the stonnwater management controls.
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9.02 - Maintenance Agreement for Privately Owned Stormwater Facilities
9.02.1 Prior to final approval of the site's stormwater management plan (including a SWM Site Plan under Section 6.03 and/or a Simplified Method or Small Projects Application under Section 6.020, the applicant and Township shall execute a Stormwater Management ("SWM") Maintenance Agreement covering all stormwater control facilities which are to be privately owned. The SWM Maintenance Agreement shall be recorded with the final subdivision/land development plan for the site and as a part of the Developer's SWM Site Plan. The agreement shall stipulate that:
(1) All facilities, including but not limited to stormwater BMPs, shall be maintained in accordance with the approved maintenance schedule and in a safe and ath·active manner.
(2) Easements and or rights-of-way shall be conveyed to the Township to assure access for periodic inspections by the Township and maintenance if required.
(3) The name, address and telephone number of the person or company responsible for maintenance activities shall be fi led with the Township. In the event of a change, new information will be submitted to the Township within ten (10) days of the change.
(4) If the facility owner fails to maintain the stormwater control facilities, the Township may perform tbe necessary maintenance work or corrective work following due notice by the Township to the facility owner to correct the problem(s). The facility owner shall reimburse the Township for all costs.
( i) All sums invoiced by Millcreek Township as reimbursement for its costs in providing maintenance not provided by the owner shall constitute a "municipal claim" as defined in the general municipal law, 53 P.S. § 7101, et seq. and shall be enforceable and collectible as such.
(ii) Interest shall acclUe on all sums so invoiced and not paid within thi1ty (30) days after the invoice date at the rate of ten percent ( J0%) per year from the invoice date.
(5) The Township shall be entitled to enforce such agreement by an action at law or in equity, including an action for specific perfonnance, in which event the owner shall in addition to other relief warranted be compelled to pay to Millcreek Township all attorney's fees, costs and expenses thereby incurred by the Towns~p.
9.02.2 Other items may be included in the agreement where determined necessary to guarantee the satisfactory maintenance of all facilities.
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9.03 - Miscellaneous Provisions
9.03.1 Any agreement of Millcreek Township to provide inspection and/or maintenance services under this Article shall not serve to impose upon the Township, its officials, departments or employees any liability arising out of the calculations, design or construction of the said facility.
9.03.2 The provisions of this Article shall be an express condition upon approval of any subdivision, land development or other development plan subject to the provisions of this Ordinance.
9.03.3 Millcreek Township shall not be obligated to perform any inspection, maintenance or other services to or upon privately owned facilities absent the owner's prior execution of an agreement acceptable to the Township and the owner's prepayment to the Township of all fees due for performance of the specified services for the next following year subject to the agreement. An owner's failure to prepay such fees prior to commencement of the next year ofperfonnance shall immediately terminate such agreement and all obligations ofMillcreek Township theretmder.
9.03.4 Recording of Approved SWM Site Plan and Related Agreements. The owner of any land upon which permanent stormwater BMPs will be placed, constructed or implemented, as described in the SWM Site Plan, shall record the following documents in the office of the Erie County Recorder ofDeeds within ninety (90) days after approval of the SWM Site Plan by the Township:
(1) The SWM Site Plan-Please refer to Section 6.03 and, at a minimum, those items in Section 6.03.1(1)-(10), (12)-(18), (22)-(24) and (27)-(29) must be included unless excused by Resolution of the Board of Supervisors;
(2) Ownership and maintenance detail, if any, from the SWM Repott not otherwise included above;
(3) The SWM Maintenance Agreement as approved by the Township; and
(4) Easements requi1·ed under Section 8.01 and not clearly dedicated on the development plan as recorded.
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ARTICLE 10 INSPECTIONS OF STORMWATER MANAGEMENT CONTROLS
10.01 - Construction Inspections
10.01.1 The Township Engineer or a designated representative of the municipality shall inspect the construction of the temporary and permanent stotmwater management system for the development site. The permittee shall provide to the Township Engineer and the engineer retained to conduct stonnwater management plan reviews and inspections written notice of intention to commence worf< to be received at least 48 hours prior to commencement of construction, and the permittee shall thereafter keep the Township Engineer and retained engineer apprised of the permittee's progress and schedule of work.
10.01.2 If there are deficiencies in any phase, the Township Engineer shall issue a written description of the required corrections and stipulate the time by which they must be made. The Township shall have authoritY to direct performance of work deemed necessa1y to protect downstream properties during the course of development activity.
10.01.3 If during conshuction, the contractor or permittee identifies any site condition, such as subsurface soil conditions, alterations in surface or subsurface drainage which could affect the feasibility of the approved stonnwater facilities, he/she shall notify the Township Engineer within 24 hours of the discovery ofsuch condition and request a field inspection. The Township Engineer shall determine if the condition requires a stonnwater plan modification.
10.01.4 In cases where stormwater facilities are to be installed in areas of landslide-prone soils or other special site conditions exist, the Township may require special precautions such as soil tests and core borings, full-time inspectors and/or similar measures. All costs of any such measures shall be borne by the pe1mittee.
10.01.5 All inspections shall be conducted by the engineer responsible for review and certification of such plan, or his or her designee.
10.01.6 Where stormwater facilities are to be dedicated to and accepted by the Township, the engineer shall conduct such inspections as are required to enable the engineer to certify to the Board of Supervisors, prior to the Board's acceptance of the facilities and/or reduction or release of security pertinent to their construction or integrity, that such facilities have been constructed in full conformity with this Ordinance and the approved stormwater management plan.
58 PaDEP 125
ARTICLE 11 FINANCIAL GUARANTEES AND DEDICATION OF PUBLIC IMPROVEMENTS
11.01 -Financial Guarantees
11.01.1 Guarantee of Completion: A completion guarantee in a form of financial secmity accepted under Section 6.19 of the Subdivision and Land Development Ordinance shall be tendered to the Township prior to release of the development plan for recording to ensure completion of all required stmmwater management facilities. The amount of such financial security shall be calculated and the security shall be held in accordance with the Township's Subdivision and Land Development Ordinance. Such security must provide that, upon written certification by the Township that all or a portion of the improvements subject thereto have not been completed in proper or timely fashion, funds under the security shall be immediately paid over to the Township.
11.01.2 Release of Completion Guarantee: The procedures for requesting and obtaining a release of the financial security shall be in a manner prescribed by Section 6.19 of the Subdivision and Land Development Ordinance.
11 .01 .3 Default of Completion Guarantee: Ifimprovements are not installed in accordance with the approved fmal plan, the Board of Supervisors may enforce any financial security by appropriate legal and equitable remedies. If proceeds of such financial secmity are insufficient to pay the cost of installing or making repairs or corrections to all the improvements covered by said security, the Township, at its option, may install part of such improvements in all or part of the development and may institute appropriate legal or equitable action to recover the funds necessaty to complete remaining improvements. All proceeds, whether resulting from the security or from any legal or equitable action brought against the developer, or both, shall be used solely for the installation of the improvements covered by such security and not for any other municipal purpose.
11.02 - Dedication of Public Improvements
11.02.1 Procedures governing dedication and acceptance of public improvements by the Township, water and sewer authorities and other governmental agencies shall be as set forth in the Municipalities Planning Code, the Subdivision and Land Development Ordinance and regulations of other governmental agencies responsible for accepted improvements. Improvements shall be deemed private until such time as they have been offered for dedication and accepted as a public improvement by resolution or ordinance of the Township or other applicable governmental agency.
11.02.2 A development and stormwater management plan shall identify clearly those improvements which ru·e to be offered for dedication for public use and the governmental agency to which dedication is offered. The Township shall accept dedication of storm water management facilities only where located within rights of way of a public street or as otherwise authorized in this Ordinance. Prior to acceptance by the Township of any improvements or facilities, the Township Engineer, a consulting engineer retained by the Board of Supervisors or their designee shall inspect them to ensure that they have been constructed in full conformity with the approved plan and Township specifications and are functioning properly. Any stonnwater control facility must be free of sediment and debris prior to acceptance by the Township.
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11.02.3 The developer offering said facilities for acceptance by the Township shall be responsible for payment of all inspection and engineering fees incurred in this process, which fees shall be paid in full to Millcreek Township prior to acceptance of such improvements. Regulations of water and sewer authorities, PennDOT and other agencies to whom dedication of certain constructed improvements is offered shall control with regard to their completion and acceptance.
11.02.4 The owner shall submit as-built plans for all facilities proposed for dedication, certified by a professional engineer. Complete certified as-built plans shall be provided to the Township's retained engineer prior to issuance ofthe engineer's certification ofcompletion.
11.02.5 Prior to acceptance of any detention and/or retention facility, the applicant shall provide financial security to secure the structural integrity and functioning of the said facility(ies). The secmity shall be (1) in a form accepted by the Township under Section 6.19 of the Subdivision and Land Development Ordinance, (2) in effect for a term of 36 months, and (3) be in an amount equal to 25 percent of the actual cost of the improvements and facilities so dedicated. Security for all other development improvements shall be fixed and administered pursuant to the Subdivision and Land Development Ordinance.
11.03 - Express Conditions Upon Acceptance of Dedication
11.03.1 Any acceptance by Millcreek Township of dedication of storm detention or retention facilities shall be subject to the following conditions:
(1) Such acceptance shall not constitute assumption by the Township of responsibility or liability arising out of errors, omissions, miscalculations or misrepresentations (whether accidental, negligent, recldess or intentional) upon which the stormwater management plan submitted by the developer and certified by the developer's engineer was wholly or in part based.
(2) The developer and its engineer shall remain liable under the Storm water Management Act and this Ordinance to the Township and third parties for loss, damage and expense, including attorney's fees and litigation expenses, incuned as a result or arising out of deficient or negligent calculations, design and/or construction of the facility, and shall be obligated to hold Millcreek Township harmless against any and all claims of personal injmy and/or property damage arising out of such negligence.
(3) No action for damages shall be deemed to arise until the date upon which defects in calculation, design and/or construction of the facility is frrst known by the Township to exist.
(4) No stormwater detention/retention facility shall be accepted by the Board of Supervisors unless (a) it has been enclosed by a fence acceptable to the Township; (b) it has a maximum side slope not exceeding 4: 1 horizontal to vertical dimension and (c) Applicant bas paid to the Township a fee for 10 years' inspections as established by the Board of Supervisors. Where the nature, physical conditions and/or topography of the development, the facility or the adjacent lands are such that a side slope of 4:1 does not adequately allow for safe and efficient maintenance, the Board of Supervisors in its discretion may require a maximum side slope of 5: 1 horizontal to vertical dimension.
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( 5) The Board of Supervisors shall have received from an engineer to whom the proposed stom1water management plan was refened his/its certification that such plan and the facilities proposed to be dedicated have been completed in full conformity with the approved plan, this Ordinance, the Public and Private Improvements Code and all applicable laws and regulations.
11.03.2 The Board of Supervisors shall not accept dedication of any stormwater detention/retention facility without first receiving the written and signed agreement of the applicant and the applicant's engineer to the express conditions set fo1th above.
11 .03.3 This Ordinance shall not be constmed so as to impose upon the Board of Supervisors an obligation to accept dedication of any stormwater detention/retention facility unless the Board should so elect, and subject to such additional conditions as the Board may impose.
ARTICLE 12 FEES AND ADMINISTRATION
12.01 - Fee Schedule
The Board of Supervisors may adopt by resolution from time to time a _reasonable schedule of fees to cover the cost of plan reviews, inspections and other activities necessary to administer the provisions of this Ordinance. All fees shall be set in accordance with the applicable provisions of the Pennsylvania Municipalities Planning Code and any dispute over the fee amount shall be resolved in the manner prescribed by the Pennsylvania Municipalities Planning Code.
12.02 - Developer Obligated to Pay all Fees
All fees and expenses associated with the review, inspection, oversight and administration of stormwater management plans shall be paid by the developer. Filing and review fees shall defray ongoing administration of this Ordinance.
12.03 - Administration
The Board of Supervisors shall have authority to delegate responsibilities for administration and implementation of this Ordinance, and to establish by Resolution fees and procedures.
12.04 - Modifications
The Engineer retained by the Township may allow reasonable modification of regulations if an applicant demonstrates that the requirements and objectives of this Ordinance can be met by alternative methods.
62 128
ARTICLE 13 PROHIBITED ACTS, ENFORCEMENT PROCEDURES AND REMEDIES
13.01 -Prohibited Acts
The following acts are prohibited and shall be subject to enforcement procedures, remedies and penalties for violation:
13.01.1 No discharge oftoxic materials shall be permitted into any st01mwater management system. Where required by federal and state regulation, the landowner or developer shall be responsible for obtaining an NPDES for stormwater discharges.
13.01.2 Any drain (including indoor drains and sinks) or conveyance, whether on the surface or underground, that allows any non-stormwater discharge (including sewage, process waste water and wash water) to enter into the separate storm sewer system, watercourse or waters of the Commonwealth is prohibited.
13.01.3 No drain or conveyance shall be connected from a commercial or industrial land use to the separate stonn sewer system without documentation in plans, maps or equivalent records submitted to the Towns~p and without prior approval of the Township.
13.01.4 No person shall allow, or cause to allow, discharges into the Township's separate storm sewer system or into surface waters of the Commonwealth which are not composed entirely of stormwater, excepting only discharges allowed under a federal or state permit or the following discharges, which are authorized unless they are determined to be significant contributors to pollution to waters of the Commonwealth:
(1) Discharges from fire-fighting activities; (2) Potable water sources including dechlorinated water line and fire hydrant flushings; (3) Irrigation drainage or springs; (4) Air conditioning condensate; (5) Water from crawl space pumps; (6) Flows from riparian habitats and wetlands; (7) Uncontaminated water from foundations or from footing drains; (8) Lawn watering; (9) Dechlorinated swimming pool discharges; (1 0) Uncontaminated groundwater; (11) Water from individual residential car washing; ( 12) Routine external building washdown (excluding use of detergents, other compounds); (13) Dive1ted stream flows; and/or (14) Pavement wash waters where spills or leaks of toxic or hazardous materials have not occuued (unless all spill material has been removed) and where detergents not used.
63 129
13.01.5 In the event the Township or PaDEP detetmines that any of the discharges identified in Subsection 13.01.4, above, significantly contribute to pollution of waters of the Commonwealth, the Township or the PaDEP will notify the responsible person(s) to cease and terminate the discharge.
(l) Upon notice provided by the Township or the PaDEP under subsection 13.01.5, the discharger will have a reasonable time, as detemuned by the Townslup or PaDEP, to cease the discharge.
(2) Failure to cease such discharge by the time required under this Subsection shall constitute a violation of this Ordinance, and each day of continued discharge shall constitute a separate violation.
(3) Nothing in this Subsection shall affect a discharger's responsibilities under Pennsylvania law.
13.01.6 No person shall modify, remove, fill, landscape or alter any existing stormwater BMP, facilities, areas or stmctures, unless it is part of a maintenance program approved by the Township, without the written approval of the Township.
13.0 1. 7 No person shall place any structure, fill, landscaping or vegetation into a stonnwater BMP, facility, areas, structures or within a drainage easement which would limit or alter the functioning ofthe BMP or impede access to the easement premises, without the prior written approval of the Township.
13.02 -Notification
In the event that the applicant, developer, owner or his/her agent fails to comply with the requirements of this Ordinance or fails to conform to the requirements of any permit, a written notice of violation shall be issued by the Township Engineer or any designated municipal official. Such notification shall set forth the nature of the violations(s) and establish a time limit for correction of the violation(s). Upon failure to comply within the time specified, unless otherwise extended by the Township, the applicant, developer, owner or his/her agent shall be subject to the enforcement remedies of this Ordinance.
13.03 - Preventive Remedies
13.03.1 In addition to other remedies, the Township may institute and maintain appropriate actions by law or in equity to restrain, conect or abate a violation, to prevent unlawful construction, to recover damages and to prevent illegal occupancy of a building or premises.
13.03.2 In accordance with the Pennsylvania Municipalities Planning Code (Sec. 515.1), the Township shall refuse to issue any permit or grant approval to further improve or develop any property which bas been developed in violation of this Ordinance, this extending to those persons referenced in said section.
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13.04 -Enforcement Remedies
13.04.1 Enforcement Notice and Procedures
(1) Enforcement Notice. If it appears to the Township that a violation of this Ordinance has occurred, the Township shall initiate enforcement proceedings by sending an enforcement notice. Such enforcement notice shall comply with requirements therefor as set forth in MPC Section 616.1 and in Ordinance Nos. 2007-6 and 96-8, as amended.
(2) Service of Notice. An enforcement notice shall be sent to the owner of record of the parcel on which the violation has occurred, to any person who has filed a written request to receive enforcement notices regarding that parcel and/or to any other person requested in writing by the owner of record.
13.04.2 Penalties for Violation. Any person who or which has violated or pennitted the violation of any provision(s) of this Ordinance shall, upon being found liable therefor in a civil enforcement proceeding commenced by the Township in accordance with Ordinance No. 96-8, as amended, pay a judgment of Six Hundred Dollars ($600.00) for each such violation, plus all court costs and including all attorney's fees incmred by the Township as a result thereof. No judgment shall commence or be imposed, levied or payable until the date of detennination of a violation by the District Magisterial Judge.
13.04.3 Continuing Violations. Each day that a violation continues shall constitute a separate violation, unless the District Magisterial Judge detennining that there has been a violation further detennines that there was a good faith basis for the person or entity violating the Ordinance to have believed that there was no such violation, in which event there shall be deemed to have been only one such violation until the fifth day following the date of the detennination of a violation by the District Magisterial Judge. Thereafter, each day that a violation continues shall constitute a separate violation.
13.04.4 Payment of Judgments, Costs and Fees. All judgments, costs and reasonable attorney fees collected for the violation of this Ordinance shall be paid over to Millcreek Township.
13.04.5 Collection of Judgment. If the defendant neither pays nor timely appeals the judgment entered by the District Magisterial Judge, the Township may enforce the judgment pursuant to the applicable Rules of Civil Procedure.
13.04.5 Remedies Non-Exclusive. In the event of a violation of any provision of this Ordinance, the Township shall have authority to exercise or pursue any or all of the remedies available to it under this Article, the Municipalities Planning Code and other applicable laws and ordinances. Election by the Township of one or more remedies shall not be deemed to exclude exercise of other available remedies.
13.04.6 Private Enforcement Not Authorized. Nothing contained in this Section shall be construed or intetpreted to grant to any person or entity other than the Township the right to commence any action for enforcement pursuant to this section; provided, however, that this Ordinance shall not be construed or intetpreted to deprive persons of their private rights or remedies under the Act.
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ARTICLE 14 MISCELLANEOUS PROVISIONS
14.01- Appendices Incorporated
The following Appendices are attached to this Ordinance:
Appendix A Release Rate Map Assigned Release Rate Percentages
Appendix B Permissible Velocities for Channels
Appendix C Simplified Method Detail
Appendix D Stormwater Management Design Criteria
14.02 - Authority of Board of Supervisors
14.02.1 The Board of Supervisors, by Resolution, shall have authority to amend all or any ofthe said appendices to this Ordinance at any time.
14.02.2 The Board ofSu pervisors by Resolution shall from time to time establish forms, agreements, filing, maintenance and inspection fees and other documents necessary to implement the provisions ofthis Ordinance.
BE IT ENACTED this K_ day of October, 2011.
2011-11/MLK/ORDS
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1 APPENDIX A
RELEASE RATE MAP AND ASSIGNED RELEASE RATE PERCENTAGES LEGEND c:::::J 70Z RELEASE RATE ERlE c:::::J BOX RELEASE RATE LAKE - 90X RELEASE RATE - lDDX RELEASE RATE
MILLCREEK TOWNSHIP
STORM WATER MANAGEMENT ORDINANCE
REF: LAKE ERIE AREA WATERSHED STORMWATER MANAGDIENT PLAN, 1996. 134
A-2 Assigned Release Rate Percentages
Release Rate Area Asshmed Release Release Rate Area Asshmed Release 1 100 26 90 2 80 27 80 3 90 28 80 4 80 29 90 5 70 30 80 6 90 31 80 7 80 32 90 8 80 33 80 9 90 34 90 10 80 35 70 11 80 36 80 12 80 37 80 13 80 38 90 14 80 39 90 15 70 40 80 16 90 41 90 17 90 42 70 18 80 43 80 19 80 44 80 20 80 45 70 21 90 46 90 22 70 47 80 23 100 48 80 24 80 49 80 25 RO "iO 70
Note: Release Rate Identification Numbers refer to numbers indicated on the Release Rate Map. 135
APPENDIX 8- PERMISSIBLE VELOCITIES FOR CHANNELS ' 136
APPENDIX B PERMISSIBLE VELOCITIES FOR CHANNELS
PERMISSIBLE CHANNEL CHANNEL LINING VELOCITY CF.P.S.)
Vegetation
Alfalfa 2.5 3.5 Bermuda grass 4 8 0') Crabgrass 2.5 0 3.5 <.0 Crownvetch 3 5 01 Kentucky bluegrass 4 7 ~ Kentucky 31 tall fescue 2.5 7 ~ Red Clover or Red Fescue 2.5 3.5 Reed Canary 3 5 Ryegrass 2.5 3.5 Small grains 2.5 3 Smooth brome 3 7 Sudan grass or Timothy 2.5 3.5
Bare Earth, Easily Eroded
Fine sand 1.5 Sand loam 1.75 Silt loam or alluvial silts, loose 2 Firm loam 2.25
Bare Earth, Erosion Resistant
Fine gravel 2.5 Stiff clay or alluvial silts, firm 3 Loam to cobbles (graded) 3.75 Silt to cobbles (graded or coarse gravel) 4 Cobbles and stones or shales and hardpans 5 Durable bedrock 8
Other
Plastic 4 6" Rip Rap 6 Asphalt 7 9" Rip Rap 8 12" Rip Rap or wood 9 Concrete or steel 12
Slope, soil condition, climate and management must be considered in channel design. If different channel linings exist in a channel, and size and slope do not change, the channel should be designed for the lining with the lower velocity listed.
Where velocity ranges are listed, the lower velocity is for design with easily eroded soils and slopes greater than 10%. The higher velocity is for design with erosion-resistant soils and slopes less than 10%. 137
APPENDIX C- SIMPLIFIED SWM METHOD DETAIL Millcreek Township: Simplified Detention Basin Chart for Small Watersheds 800 ..,. :g 0 1o -- L .L. -- - -o- .... 9{) ~ - :-- 700 L L ..,. ,. -OS:: ..... , , 1/ ::J L - ~ 600 ..,. , L Q) - E _..,. _..,. 1/ ::J ..,. L • 0 - """- ~ [e > loO"' -iQ9JC -t e as..., ~ 500 !L ,.. I e ~ L ...... 52 - .L...... s L L' , Cl) ~ I "0 ..,., V-b ~ 400 L A; ::J q. - ~ C" ~~ _..,. Q) . % 0::: Z I Q ~ ., L ~ 300 ,7 r .... L l~ ~ r:::;;ii ~% .....
200 I 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 Impervious Surface Area (sq. ft.)
L~9609 139
Length of perforated pipe (in feet) required In a single or multiple pipe detention system to attain the required volume.
Required Volume 30" Pipe (cu. ft.l 2 3 4 2 3 4 2 3 4 1 2 3 4 1 2 3 4 200 163 81 54 40 113 56 37 28 64 31 21 15 41 20 13 10 r;: 28 13 9 7 220 179 89 59 44 124 62 41 30 70 35 23 17 45 22 15 11 1: 31 15 10 7 240 196 97 65 48 136 67 45 33 76 38 25 18 49 24 16 12 ;: 34 16 11 8 260 212 105 70 52 147 73 48 36 .• 83 41 27 20 r. 53 26 17 13 " 37 18 12 9 280 228 114 75 56 158 79 52 39 89 44 29 22 ;~ 57 28 19 14 40 19 13 10 300 244 122 81 60 170 84 56 42 ; 95 47 31 23 ·~ 61 30 20 15 42 20 14 10 320 261 130 86 64 ;! 181 90 60 45 102 50 33 25 65 32 21 16 .· ~ 45 22 15 11 340 277 138 92 69 192 96 63 47 108 54 35 26 69 34 23 17 48 23 16 12 360 293 146 97 73 204 101 67 50 115 57 38 28 73 36 24 18 51 25 16 12 380 310 154 103 77 215 107 71 53 121 60 40 29 77 38 25 19 54 26 17 13 400 326 162 108 81 226 113 75 56 ~ 127 63 42 31 81 40 27 20 r,, 57 28 18 14 420 342 171 113 85 238 118 79 59 134 66 44 33 ~ ~ 86 42 28 21 lir 59 29 19 14 440 359 179 119 89 249 124 82 61 140 70 46 34 r~ 9o 44 29 22 s2 30 20 15 460 375 187 124 93 260 130 86 64 146 73 48 36 I '~ 94 46 31 23 65 32 21 16 480 391 195 130 97 272 135 90 67 153 76 50 37 98 48 32 24 68 33 22 17 500 407 203 135 101 283 141 94 70 159 79 52 39 102 50 34 25 71 35 23 17 520 424 211 141 105 294 147 97 73 166 82 55 41 106 52 35 26 74 36 24 18 540 440 220 146 109 306 152 101 76 172 85 57 42 110 54 36 27 76 37 25 19 560 456 228 151 113 317 158 105 78 178 89 59 44 114 56 38 28 l~ 79 39 26 19 580 473 236 157 117 328 164 109 81 185 92 61 45 r':l 118 58 39 29 82 40 27 20 600 489 244 162 121 340 169 113 84 191 95 63 47 I ~ 122 so 4o 3o ~ a5 42 28 21 620 505 252 168 126 351 175 116 87 197 98 65 49 . • 126 63 42 31 88 43 29 22 640 522 260 173 130 362 181 120 90 204 101 67 50 130 65 43 32 91 45 30 22 660 538 268 179 134 373 186 124 93 210 105 69 52 134 67 44 33 93 46 31 23 680 554 277 184 138 385 192 128 95 216 108 71 53 139 69 46 34 96 47 32 24 700 570 285 189 142 396 198 131 98 ~ 223 111 74 55 143 71 47 35 99 49 33 24 720 587 293 195 146 407 203 135 101 f! 229 114 76 57 147 73 48 36 102 50 33 25 740 603 301 200 150 419 209 139 104 236 117 78 58 ~ 151 75 50 37 105 52 34 26 760 619 309 206 154 ·~ 430 215 143 107 242 120 80 60 155 77 51 38 108 53 35 27 780 636 317 211 158 441 220 146 110 248 124 82 61 :· 159 79 53 39 110 54 36 27 800 652 325 217 162 ~ 453 226 150 112 .... 255 127 84 63 l..,o. 163 81 54 40 113 56 37 28
Number of lengths of pipe used in a single or manifold pipe system. 140
Single Orifice Diameter to be Used in Conjunction with Simplified Detention Basin Design.
Release Total Im11ervious Surface (sg. ft) Rate(%) <13750 L 750- 23250- 23750- 3.250- 33750- 43250- 43750 + 23250 23750 33250 3,750 4,250 43750 Orifice Size Reguired (in) 100 1 112 1% 2 2 2 2% 2% 2% 90 1112 1% 1% 2 2 2% 2% 2% 80 1112 1112 1% 1% 1% 2 2% 2% 70 1112 1 112 1% 1% 1% 1% 2 2
1 PLAN VIEW OUTLET PIPE 12" MINIMUM OUTLET STRUCTIJRE r GRATE ORIFICE PLATE (d/s of grate) I I L__ __j L__ I I GRATE NOT SHOWN I -- ~ :·1 I A A FOR CLARITY A I (;;) 11 ll CONNECTOR PIPE I 12" MINIMUM -----.... I SECTION A-A I -EB- I
UNDERGROUND --EB-- STORAGE PIPES 1 MINIMUM SLOPE = 0.5% I
v \ v COMPLY WITH ACCESS/CLEANOUT PORTS /1 ?I MANUFACTURERS SPACING RISER SIZE SAME AS DETENTION PIPE; 24" DIAMETER MAX. ~-----~---- RECOMMENDATIONS Millcreek Township CONSTRUCTION STANDARDS Erie County, Pennsylvania UNDERGROUND STORAGE N.T.S. 3608 West 26th Street TYPICAL DETAILS Erie, PA 16506 814-833-1111 HILL ENGINEERING, INC. www .millcreektoWDSbip.com 8 ca. Sift
APPENDIX D - STORM WATER MANAGEMENT DESIGN CRITERIA 143
TABLE 0-1 - RATI ONAL M ETH OD RU NOFF COEFFICIENTS Hydraulic Storm Soil Group A . B c D Slope Range 0-2% 1 2-6% +6% 0-2% 1 2-6% I +6% 0-2% I 2-6% I +6% 0-2% 1 2-6% +6% Cultivated <25yr 0.08 0.11 0.21 0.18 0.13~ I 0.15 I o.14 1 o.19 ~ 0.23 0.31 Land ~25yr 0.14 0.08 0.22 0. 16 I o.21 0.28 o.2 I o.25 o.34 0.24 0.29 I 0.41 Pasture <25yr 0.12 ~I o.3 0.18 0.28 0.37 o.24 I o.34 0.44 0.3 0.4 I 0.5 ~25yr 0.15 I o.37 0.23 0.34 0.45 0.3 0.42 I 0.52 0.37 0.5 0.62 Meadow <25yr 0.10 0.16~ 0.14 0.22 I 0.3 0.2 o.28 I 0.36 0.24 0.3 0.4 ~25yr 0. 14 0.22 0.3 0.2 0.28 0.37 0.26 I o.35 I 0.44 0.3 I 0.4 0.5 Forest <25yr 0.05 0.08 1 0.11 0.08 0.11 0.14 0.1 I o.13 0.16 0.12 0.16 0.2 ~25yr 0.08 0.11 0.14 0.1 0.14 0.18 0.12 0.16 0.2 0.15 0.2 0.25 Residential 1/8 Acre <25yr 0.25 0.28 0.31 0.27 0.3 0.35 *0.33 0.38 0.33 0.36 0.42 ~25yr 0.33 0.37 I 0.4 0.35 0.39 0.44 0.42 0.49 0.41 0.45 0.54 1/4 Acre <25yr 0.22 0.2.6 I 0.29 0.24 0.29 0.27 0.31 0.36 0.3 0.34 0.4 ~25yr 0.3 0.34 I o.37 0.33 0.37 ~2 0.36 0.4 0.47 0.38 0.42 0.52 1/3 Acre <25:tr 0.19 0.23 0.22 0.26 0.3 0.25 0.29 0.34 0.28 0.32 0.39 225yr 0.28 0.32 ~ 0.3 0.35 0.39 0.33 0.38 0.45 0.36 0.4 0.5 1/2 Acre <25yr 0.16 ~ 0.24 0.19 0.23 0.28 0.22 I 0.27 0.26 I 0.3 f 0.37 225yr 0.25 0.32 0.28 0.32 0.36 0.31 0.35 ~2 0.34 0.38 0.48 1 Acre <25yr 0.14 I 0.19 I 0.22 ~_ 0 . 21H* 0.2 0.25 I 0.31 0.24 0.29 0.35 225yr - 0.22 o.26 I o.29 0.28 0.34 0.28 0.32 0.4 0.31 0.35 0.46 I I I ' I Industrial <25yr 0.67 I 0.6?__1 0.68 _ 0.68 I 0.68 0.69 0.68 0.69 0.69 0.69 0.69 I 0.7 225yr 0.85 o.85 I o.86 0.85 0.86 0.86 0.86 0.86 0.87 0.86 0.86 0.88 Commercial _<25yr __0.71 __ _QZJ_I Q.72_ 0.71 0.72 _Q.72 0.72 0.72 0.72 0.72 ---~ ~_gn_ l 225yr 0.88 10.88 0.89 0.89 0.89 0.89 0.89 0.89 0.9 o.89 I 0.9 Streets <25y_r 0.7 0.71 0.72 0.71 0.72 0.74 0.72 0.73 0.76 0.73 0.75 ~ ~25yr 0.76 0.77 0.79 0.8 0.82 0.84 0.84 0.85 0.89 0.89 0.91 0.95 Open <25yr S1;2ace 0.05 0.1 0.14 0.08 I 0.13 l 0.19 0.12 0.17 I 0.24 0.16 0.21 I 0.28 225yr 0.11 0.16 0.2 0.14 I 0.19 I o.26 0.18 0.23 0.32 0.22 0.27 0.39 Parking or <25yr 0.85 I o.86 I 0.87 0.85 0.86 0.87 0.85 I o.86 I 0.87 0.85 0.86 0.87 Impervious 225yr 0.95 I o.96 I 0.97 0.95 0.96 0.97 0.95 I o.96 I 0.97 0.95 0.96 0.97
Source: Rawls, W.J., S.L. Long, and R.H. McCuen, 1981. Comparison of Urban Flood Frequency Procedures. Preliminary Draft Report prepared for the Soil Conservation Service, Beltsville, Maryland.
For simplification, a designer may use 0.3 for all pervious areas and 0. 95 for all impervious areas. 144
TABLE D-2 - RUNOFF CURVE NUMBERS {FROM NRCS {SCS) TR-55)
Runoff Curve Numbe rs for Urban Areas Curve Numbers for Cover Description Hydrologic Soil Groups Average Percent Cover Type and Hydrologic Condition A B c D Impervious Area Fully Developed Urban Areas {Veqetation Established} Open Space (lawns, parks, golf courses, etc): Poor Condition (grass cover < 50%) 68 79 86 89 Fair Condition (grass cover 50% to 75%) 49 69 79 84 Good Condition (grass cover> 75%) 39 61 74 80 Impervious Areas: Paved Parking Lots, Roofs, Driveways, etc. 98 98 98 98 Streets and Roads: Paved: Curbed and Storm Sewers 98 98 98 98 Paved: Open Ditches 83 89 92 93 Gravel 76 85 89 91 Dirt 72 82 87 89 Urban Districts: Commercial and Business 85% 89 92 94 95 Industrial 72% 81 88 91 93 Residential Districts by Average Lot Size: 1/8 Acres or less 65% 77 85 90 92 1/4 Acre 38% 61 75 83 87 1/3 Acre 30% 57 72 81 86 1/2 Acre 25% 54 70 80 85 1 Acre 20% 51 68 79 84 2 Acres 12% 46 65 77 82 145
Runoff Curve Numbers for Cultivated Agricultural Lands Cover Description Curve Numbers Hydrologic Cover Type Treatment A 8 c D Condition Bare Soil -- 77 86 91 94 Fallow Poor 76 85 90 93 Crop Residue Cover (CR) . Good 74 83 88 90 Poor 72 81 88 91 Straight Row (SR) Good 67 78 85 89 Poor 71 80 SR+ CR 87 90 Good 64 75 82 85 Poor 70 79 84 Contoured (C) 88 Good 65 75 82 86 Row Crops Poor 69 78 83 87 C+CR Good 64 74 81 85 Poor 66 74 80 82 Contoured & Terraced (C & T) Good 62 71 78 81 Poor 65 73 79 81 C & T+ CR Good 61 70 77 80 Poor 65 76 84 88 SR Good 63 75 83 87 Poor 64 75 83 86 SR+ CR Good 60 72 80 84 c Poor 63 74 82 85 Good 61 73 81 84 Small Grain Poor 62 73 81 84 C+CR Good 60 72 80 83 Poor 61 72 79 82 C&T Good 59 70 78 81 Poor 60 71 78 C & T+ CR 81 Good 58 69 77 80 Poor 66 77 85 89 Close Seeded or SR Good 58 72 81 85 Broadcast Poor 64 75 83 85 Legumes c Good 55 69 78 83 Or Rotation Poor 63 73 80 83 Meadow C& T Good 51 67 76 80 Runoff Curve Numbers for Other Agricultural Lands Poor 68 79 86 89 Pasture, Grassland, or Range- Continuous Forage for Grazing Fair 49 69 79 84 Good 39 61 74 80 Meadow-Continuous Grass, Protected from Grazing and Generally Mowed for Hoy -- 30 58 71 78 Poor 57 73 82 86 Woods- Grass Combination (orchard or tree farm) Fair 43 65 76 82 Good 32 58 72 79 Poor 45 66 77 83 Woods Fair 36 60 73 79 Good 30 55 70 77 Farmsteads - Buildings, Lanes, Driveways and Surroundinq Lots. - 59 74 82 86
Erie County Act 167 Plan Phase II - Model Ordinance Page-3