A. 
The Board of Supervisors may grant a modification if literal enforcement of the requirements of one or more provisions of this chapter will exact undue hardship because of peculiar conditions pertaining to the land in questions, provided that such modification will not be contrary to the public health, safety and welfare, and may permit a modification of the requirements of this chapter subject to conditions necessary to assure adequate management of stormwater.
B. 
All requests for modification shall be in writing and shall accompany and be a part of the application for stormwater management plan approval. The request shall state in full the grounds and facts of unreasonableness or hardship on which the request is made, the provision or provisions of this chapter involved and the minimum modification necessary.
C. 
After receipt of a request for modification, the Township shall forward the same to the Planning Commission for advisory comments.
A. 
This chapter shall only apply to permanent stormwater management facilities constructed as part of any of the regulated activities listed in this section. Stormwater management and erosion and sedimentation control during construction activities are specifically not regulated by this chapter but shall continue to be regulated under existing laws and ordinances.
B. 
This chapter contains only the stormwater management performance standards and design criteria that are necessary or desirable from a watershed-wide perspective. Local stormwater management design criteria (e.g., inlet spacing, inlet type, collection system design and details, outlet structure design, etc.) shall continue to be regulated by the applicable municipal ordinances.
C. 
The following activities are defined as "regulated activities" and shall be regulated by this chapter:
(1) 
Land development.
(2) 
Subdivision.
(3) 
Construction of new or additional impervious or semipervious surfaces (driveways, parking lots, etc.).
(4) 
Construction of new buildings or additions to existing buildings.
(5) 
Diversion or piping of any natural or man-made stream channel.
(6) 
Installation of stormwater management facilities or appurtenances thereto.
Any ordinance or ordinance provision of Greene Township inconsistent with any of the provisions of this chapter is hereby repealed to the extent of the inconsistency only.
Should any section or provision of this chapter be declared invalid by a court of competent jurisdiction, such decision shall not affect the validity of any of the remaining provisions of this chapter.
Approvals issued pursuant to this chapter do not relieve the applicant of the responsibility to secure required permits or approvals for activities regulated by any other applicable code, rule, act, or ordinance.
For the purposes of this chapter, certain terms and words used herein shall be interpreted as follows:
A. 
Words used in the present tense include the future tense; the singular number includes the plural, and the plural number includes the singular; words of masculine gender include feminine gender; and words of feminine gender include masculine gender.
B. 
The word "includes" or "including" shall not limit the term to the specific example but is intended to extend its meaning to all other instances of like kind and character.
C. 
The word "person" includes an individual, firm, association, organization, partnership, trust, company, corporation, or any other similar entity.
D. 
The words "shall" and "must" are mandatory; the words "may" and "should" are permissive.
E. 
The words "used or occupied" include the words "intended, designed, maintained, or arranged to be used, occupied or maintained.
ACCELERATED EROSION
The removal of the surface of land through the combined action of man's activity and the natural processes at a rate greater than would occur because of the natural process alone.
AGRICULTURAL ACTIVITIES
The work of producing crops and raising livestock, including tillage, plowing, disking, harrowing, pasturing and installation of conservation measures. Construction of new buildings or impervious area is not considered an agricultural activity.
ALTERATION
As applied to land, a change in topography as a result of the moving of soil and rock from one location or position to another; also the changing of surface conditions by causing the surface to be more or less impervious; land disturbance.
APPLICANT
A landowner or developer, as hereinafter defined, who has filed an application for approval to engage in any regulated activities as defined in § 80-5 of this chapter.
AS-BUILT DRAWING
A set of blueprints which show design or construction changes which were approved by the Township in a nonerasable red ink.
BMP (BEST MANAGEMENT PRACTICE)
Stormwater structures, facilities and techniques to control, maintain or improve the quantity and quality of surface runoff.
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 for storing rainwater.
CONSERVATION DISTRICT
The Franklin County Conservation District.
COUNTY
Franklin County, Pennsylvania.
CULVERT
A structure with appurtenant works which carries a stream under or through an embankment or fill.
DAM
An artificial barrier, together with its appurtenant works, constructed for the purpose of impounding or storing water or another fluid or semifluid, or a refuse bank, fill or structure for highway, railroad or other purposes which does or may impound water or another fluid or semifluid.
DESIGN STORM
The magnitude and temporal distribution of precipitation from a storm event measured in probability of occurrence (e.g., a five-year storm) and duration (e.g., 24 hours), used in the design and evaluation of stormwater management systems.
DESIGNEE
The agent of the Greene Township Planning Commission and/or agent of the Greene Township Board of Supervisors involved with the administration, review or enforcement of any provisions of this chapter by contract or memorandum of understanding.
DETENTION BASIN
An impoundment structure designed to manage stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate.
DETENTION DISTRICT
Those subareas in which some type of detention is required to meet the plan requirements and the goals of Act 167.
DEVELOPER
A person, partnership, association, corporation, or other entity, or any responsible person therein or agent thereof, that undertakes any regulated activity of this chapter.
DEVELOPMENT SITE
The specific tract of land for which a regulated activity is proposed.
DIFFUSED DRAINAGE DISCHARGE
Drainage discharge not confined to a single point location or channel, such as sheet flow or shallow concentrated flow.
DOWNSLOPE PROPERTY LINE
That portion of the property line of the lot, tract, or parcels of land being developed located such that all overland or pipe flow from the site would be directed towards it.
DRAINAGE CONVEYANCE FACILITY
A stormwater management facility designed to transmit stormwater runoff and shall include streams, channels, swales, pipes, conduits, culverts, storm sewers, etc.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the use of private land for stormwater management purposes.
DRAINAGE PERMIT
A permit issued by the Greene Township Board of Supervisors after the drainage plan has been approved. Said permit is issued prior to or with the final approval.
DRAINAGE PLAN
The documentation of the stormwater management system, if any, to be used for a given development site, the contents of which are established in § 80-23 of this chapter.
EARTH DISTURBANCE
Any activity, including but not limited to construction, mining, timber harvesting and grubbing, which alters, disturbs, and exposes the existing land surface.
EASEMENT
A right-of-way granted for limited use of land for public or quasi-public purpose.
ENERGY DISSIPATER
A device used to slow the velocity of stormwater particularly at points of concentrated discharged such as pipe outlets.
ENGINEER, REGISTERED PROFESSIONAL
An individual licensed and registered as a professional engineer by the Commonwealth of Pennsylvania.
ENGINEER, TOWNSHIP
The Township Engineer or any consultant designated by the Board of Supervisors to review a subdivision plan, drainage plan and perform the duties of the Township Engineer on behalf of the Township.
EROSION
The movement of soil particles by the action of water, wind, ice, or other natural forces.
EROSION AND SEDIMENT POLLUTION CONTROL PLAN
A plan that is designed to minimize accelerated erosion and sedimentation.
EXCEPTIONAL VALUE WATERS
Surface waters of high quality which satisfy Pennsylvania Code Title 25 Environmental Protection, Chapter 93, Water Quality Standards, § 93.4b(b) (relating to antidegradation).
EXISTING CONDITIONS
The initial condition of a project site prior to the proposed construction. If the initial condition of the site is undeveloped land, the land use shall be considered as "meadow" unless the natural land cover is proven to generate lower curve numbers or Rational "C" value, such as forested lands.
FEMA
Federal Emergency Management Agency.
FINISHED FLOOR
Any part of a dwelling except a totally below ground basement. Builds which have exposed basements shall include the basement as a finished floor.
FLOOD
A general but temporary condition of partial or complete inundation of normally dry land areas from the overflow of streams, rivers, and other waters of this commonwealth.
FLOOD STUDY
A computer model or manual calculation of the hydraulic surface elevation (floodplain) of a flood.
FLOODPLAIN
Any land area susceptible to inundation by water from any natural source or delineated by applicable Department of Housing and Urban Development, Federal Insurance Administration Flood Hazard Boundary - Mapped as being a special flood hazard area. Also included are areas that comprise Group 13 soils, as listed in Appendix A of the Pennsylvania Department of Environmental Protection (PaDEP) Technical Manual for Sewage Enforcement Officers (as amended or replaced from time to time by PaDEP).
FLOODWAY
The channel of the watercourse and those portions of the adjoining floodplains, which are reasonably required to carry and discharge the one-hundred-year frequency flood. Unless otherwise specified, the boundary of the floodway is as indicated on maps and flood insurance studies provided by FEMA. In an area where no FEMA maps or studies have defined the boundary of the one-hundred-year frequency floodway, it is assumed, absent evidence to the contrary, that the floodway extends from the stream to 50 feet from the top of the bank of the stream.
FOREST MANAGEMENT/TIMBER OPERATIONS
Planning and activities necessary for the management of forest land. These include timber inventory and preparation of forest management plans, silvicultural treatment, cutting budgets, logging road design and construction, timber harvesting, site preparation and reforestation.
FREEBOARD
A vertical distance between the elevation of the design high-water and the top of a dam, levee, tank, basin, or diversion ridge. The space is required as a safety margin in a pond or basin.
FREEBOARD
The difference between the design flow elevation in the emergency spillway of a basin and the top of the basin embankment after settlement occurs; and the difference between the design flow elevation of a swale and the top of the swale embankment.
GOVERNING BODY
Greene Township Board of Supervisors.
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.
GRASSED WATERWAY
A natural or constructed waterway, usually broad and shallow, covered with erosion-resistant grasses, used to conduct surface water from cropland.
GROUNDWATER RECHARGE
Replenishment of existing natural underground water supplies.
HEC-HMS
The U.S. Army Corps of Engineers, Hydrologic Engineering Center (HEC) - Hydrologic Modeling System (HMS).
HIGH QUALITY WATERS
Surface waters having quality which exceeds levels necessary to support propagation of fish, shellfish, and wildlife and recreation in and on the water by satisfying Pennsylvania Code Title 25 Environmental Protection, Chapter 93, Water Quality Standards, § 93.4b(a).
HOLDING POND
A retention or detention basin.
IMPERVIOUS SURFACE
A surface which prevents the percolation of water into the ground.
IMPOUNDMENT
A retention or detention basin designed to retain stormwater runoff and release it at a controlled rate.
IMPROVEMENTS
Physical additions and changes to the land necessary to produce usable and desirable lots.
INFILTRATION STRUCTURES
A structure designed to direct runoff into the ground (e.g., french drains, seepage pits, seepage trench).
INLET
A surface connection to a closed drain. A structure at the diversion end of a conduit. The upstream end of any structure through which water may flow.
LAND DEVELOPMENT
(1) 
Any of the following activities:
(a) 
The improvement of one or two or more contiguous lots, tracts or parcels of land for any purpose involving:
[1] 
A group of two or more residential or nonresidential buildings, whether proposed initially or cumulatively, or a single nonresidential building on a lot or lots regardless of the number of occupants or tenure; or
[2] 
The division or allocation of land or space, whether initially or cumulatively, between or among two or more existing or prospective occupants by means of or for the purpose of streets, common areas, leaseholds, condominiums, building groups or other features.
(b) 
A subdivision of land.
(2) 
Excluded from the definition of "land development" are the following:
(a) 
The conversion of an existing single-family detached dwelling or semidetached dwelling into not more than three residential units, unless such units are intended to be condominiums.
(b) 
The addition of an accessory building, including farm building, on a lot or lots subordinate to an existing principal building.
LAND EARTH DISTURBANCE
Any activity involving grading, tilling, digging, or filling of ground or stripping of vegetation or any other activity that causes an alteration to the natural condition of the land.
LANDOWNER
The legal or beneficial owner of land, including the holder of an option or contract to purchase (whether or not such option or contract is subject to any conditions); a lessee if he is authorized under the lease to exercise the rights of the landowner; or other person having a proprietary interest in the land.
LANDSCAPE ARCHITECT, REGISTERED
An individual licensed and registered as a landscape architect by the Commonwealth of Pennsylvania.
LAND SURVEYOR, REGISTERED PROFESSIONAL
An individual licensed and registered as a professional land surveyor by the Commonwealth of Pennsylvania.
MAIN STEM (MAIN CHANNEL)
Any stream segment or other runoff conveyance facility used as a reach in the Conococheague Creek hydrologic model.
MANNING EQUATION IN (MANNING FORMULA)
A method for calculation of velocity of flow (e.g., feet per second) and flow rate (e.g., cubic feet per second) in open channels based upon channel shape, roughness, depth of flow and slope. "Open channels" may include closed conduits so long as the flow is not under pressure.
MUNICIPALITY
Greene Township, Franklin County, Pennsylvania.
NONPOINT SOURCE POLLUTION
Pollution that enters a watery body from diffuse origins in the watershed and does not result from discernible, confined, or discrete conveyances.
NRCS
Natural Resource Conservation Service (previously SCS).
OPEN CHANNEL
A drainage element in which stormwater flows with an open surface. Open channels include, but shall not be limited to, natural and man-made drainageways, swales, streams, ditches, canals, and pipes flowing partly full.
ORDINANCE
This chapter shall be cited as the "Greene Township Stormwater Management Ordinance."
OUTFALL
Point where water flows from a conduit, stream, or drain.
OUTLET
Points of water disposal from a stream, river, lake, tidewater or artificial drain.
PennDOT
Pennsylvania Department of Transportation.
PARKING LOT STORAGE
Involves the use of impervious parking areas as temporary impoundments with controlled release rates during rainstorms.
PEAK DISCHARGE
The maximum rate of stormwater runoff from a specific storm event.
PENN STATE RUNOFF MODEL (CALIBRATED)
The computer-based hydrologic modeling technique adapted to the Conococheague Creek watershed for the Act 167 Plan. The model has been "calibrated" to reflect actual recorded flow values by adjoining key model input parameters.
PHREATIC LINE
The slope line of the hydraulic path of water through saturated soil.
PIPE
A culvert, closed conduit, or similar structure (including appurtenances) that conveys stormwater.
PLANNING COMMISSION
The Greene Township Planning Commission.
PMF (PROBABLE MAXIMUM FLOOD)
The flood that may be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in any area. The PMF is derived from the probable maximum precipitation (PMP) as determined based on data obtained from the National Oceanographic and Atmospheric Administration (NOAA).
PROPOSED SITE
Site conditions as they are designed to exist after development.
QUALIFIED DESIGN PROFESSIONAL
A Pennsylvania registered professional engineer, registered landscape architect or a registered professional land surveyor trained and certified to develop stormwater management plans.
RATIONAL FORMULA
A rainfall-runoff relation used to estimate peak flow.
RECEIVING STREAM
A defined channel that carries water in a nonintermittent flow.
REGULATED ACTIVITIES
Actions or proposed actions that have an impact on stormwater runoff and that are specified in § 80-5 of this chapter.
RELEASE RATE
The percentage of predevelopment peak rate of runoff from a site or subarea to which the postdevelopment peak rate of runoff must be reduced to protect downstream areas.
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.
RETURN PERIOD
The average interval, in years, within which a storm event of a given magnitude can be expected to recur. For example, the twenty-five-year return period rainfall would be expected to recur on the average of once every 25 years.
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.
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.
SEDIMENT BASIN
A barrier, dam, retention or detention basin located and designed to retain rock, sand, gravel, silt, or other material transported by water.
SEDIMENT POLLUTION
The placement, discharge or any other introduction of sediment into the waters of the commonwealth occurring from the failure to design, construct, implement or maintain control measures and control facilities in accordance with the requirements of this chapter.
SEDIMENTATION
The process by which mineral or organic matter is accumulated or deposited by the movement of water.
SEEPAGE PIT/SEEPAGE TRENCH
An area of excavated earth filled with loose stone or similar coarse material into which surface water is directed for infiltration into the ground.
SHEET FLOW
Runoff that flows over the ground surface as a thin, even layer, not concentrated in a channel.
SITE IMPROVEMENTS
Physical additions or changes to the land that may be necessary to provide usable and desirable lots, including but not limited to utilities, streets, curbing, sidewalks, streetlights and stormwater facilities.
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).
SOIL GROUP, HYDROLOGIC
A classification of soils by the Natural Resources Conservation Service, formerly the Soil Conservation Service, into four runoff potential groups. The groups range from A soils, which are very permeable and produce little runoff, to D soils, which are not very permeable and produce much more runoff.
SPILLWAY
A depression in the embankment of a pond or basin which is used to pass peak discharge greater than the maximum design storm controlled by the pond.
STORAGE INDICATION METHOD
A reservoir routing procedure based on solution of the continuity equation (inflow minus outflow equals the change in storage) with outflow defined as a function of storage volume and depth.
STORM FREQUENCY
The number of times that a given storm "event" occurs or is exceeded on the average in a stated period of years. See "return period."
STORM SEWER
A system of pipes and/or open channels that conveys intercepted runoff and stormwater from other sources but excludes domestic sewage and industrial wastes.
STORMWATER
The total amount of precipitation reaching the ground surface.
STORMWATER MANAGEMENT
The control of runoff to allow water falling on a given site to be absorbed or retained on site to the extent that, after development, the peak rate of discharge leaving the site does not exceed the rate prior to development.
STORMWATER MANAGEMENT FACILITY
Any structure, natural or man-made, that, due to its condition, design, or construction, conveys, stores, or otherwise affects stormwater runoff. Typical stormwater management facilities include, but are not limited to, detention and retention basins, open channels, storm sewers, pipes, and infiltration structures.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff in the Conococheague Creek Watershed, adopted by Franklin County as required by the Act of October 4, 1978, P.L. 864 (Act 167), and known as the "Conococheague Creek Watershed Action Act 167 Stormwater Management Plan."
STORMWATER MANAGEMENT SITE PLAN
The plan prepared by the developer or his representative indicating how stormwater runoff will be managed at the particular site of interest according to this chapter.
STREAM ENCLOSURE
A bridge, culvert or other structure in excess of 100 feet in length upstream to downstream which encloses a regulated water of this commonwealth.
SUBAREA
The smallest drainage unit of a watershed for which stormwater management criteria have been established in the stormwater management plan.
SUBDIVISION
The division or redivision of a lot, tract, or parcel of land by any means into two or more lots, tracts, parcels or other divisions of land, including changes in existing lot lines for the purpose, whether immediate or future, of lease, partition by the court for distribution to heirs or devisees, transfer of ownership, or building or lot development; provided, however, that the subdivision by lease of land for agricultural purposes into parcels of more than 10 acres, not involving any new street or easement of access or any residential dwellings, shall be exempt.
SUPERVISORS
The governing body of Greene Township.
SWALE
A low-lying stretch of land which gathers or carries surface water runoff.
TIMBER OPERATIONS
See" forest management."
TIME-OF-CONCENTRATION (Tc)
The time for surface runoff to travel from the hydraulically most distant point of the watershed to a point of interest within the watershed. This time is the combined total of overland flow time and flow time in pipes or channels, if any.
TOWNSHIP
Greene Township, Franklin County, Pennsylvania.
WATERCOURSE
A stream of water; river; brook; creek; or a channel or ditch for water, whether natural or man-made.
WATERS OF THE COMMONWEALTH
Any and all rivers, streams, creeks, rivulets, ditches, watercourses, storm sewers, lakes, dammed water, wetlands, ponds, springs, and all other bodies or channels of conveyance of surface and underground water, or parts thereof, whether natural or artificial, within or on the boundaries of this commonwealth.
WETLAND
Those areas that are inundated or saturated by surface or ground water 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, ferns, and similar areas.