Township of Upper Hanover, PA
Montgomery County
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A. 
For the purposes of this chapter, certain terms and words used herein shall be interpreted as follows:
(1) 
Words used in the present tense include the future tense; the singular number includes the plural, and the plural number includes the singular; words of masculine gender include feminine gender; and words of feminine gender include masculine gender.
(2) 
The word "includes" or "including" shall not limit the term to the specific example but is intended to extend its meaning to all other instances of like kind and character.
(3) 
The words "shall" and "must" are mandatory; the words "may" and "should" are permissive.
(4) 
The words "Supervisors" or "Board" or "governing body" shall refer to the Board of Supervisors of Upper Hanover Township.
(5) 
The words "Zoning Hearing Board" shall refer to the Zoning Hearing Board of Upper Hanover Township.
(6) 
The words "Stormwater Ordinance" mean the Upper Hanover Township Stormwater Management Ordinance.
(7) 
Terms not defined in this article shall be interpreted according to common usage or as the context may imply.
B. 
As used in this chapter, the following terms shall have the meanings indicated:
ACCELERATED EROSION
The removal of the surface of the land through the combined action of human activities and natural processes, at a rate greater than would occur because of the natural processes alone.
APPLICANT
A person who has filed an application for approval to engage in any regulated activities as defined in § 415-5.
BEST MANAGEMENT PRACTICE (BMP)
Activities, facilities, measures or procedures used to manage stormwater quantity and quality impacts from the regulated activities listed in § 415-5, to meet state water quality requirements, to promote groundwater recharge and to otherwise meet the purposes of this chapter.
BEST MANAGEMENT PRACTICE OPERATIONS AND MAINTENANCE PLAN
Documentation, included as part of a drainage plan, detailing the proposed BMPs, how they will be operated and maintained and who will be responsible.
BIORETENTION
Densely vegetated, depressed features that store stormwater and filter it through vegetation, mulch, planting soil, etc. Ultimately stormwater is evapotranspirated, infiltrated, or discharged. Optimal bioretention areas mimic natural forest ecosystems in terms of species diversity, density, distribution, use of native plants, etc.
CAPTURE/REUSE
Stormwater management techniques such as cisterns and rain barrels which direct runoff into storage devices, surface or subsurface, for later reuse, such as for irrigation of gardens and other planted areas.
CISTERN
An underground reservoir or tank for storing rainwater.
CLOSED DEPRESSION
A distinctive bowl-shaped depression in the land surface. It is characterized by internal drainage, varying magnitude, and an unbroken ground surface.
CONCENTRATED DRAINAGE DISCHARGE
Stormwater runoff leaving a property via a point source.
CONSERVATION DISTRICT
The Montgomery County Conservation District.
CONSTRUCTED WETLANDS
Constructed wetlands are similar to wet ponds (see below) and consist of a basin which provides for necessary stormwater storage as well as a permanent pool or water level, planted with wetland vegetation. To be successful, constructed wetlands must have adequate natural hydrology (both runoff inputs as well as soils and water table which allow for maintenance of a permanent pool of water). In these cases, the permanent pool must be designed carefully, usually with shallow edge benches, so that water levels are appropriate to support carefully selected wetland vegetation.
CULVERT
A pipe, conduit or similar structure including appurtenant works which carries surface water.
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.
DEP
The Pennsylvania Department of Environmental Protection.
DESIGN STORM
The depth and time distribution of precipitation from a storm event measured in probability of occurrence (e.g., one-hundred-year storm) and duration (e.g., twenty-four-hour) and used in computing stormwater management control systems.
DETENTION BASIN
A basin designed to retard stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate.
DEVELOPER
A person, partnership, association, corporation or other entity, or any responsible person therein or agent thereof, that undertakes any regulated activity of this chapter.
DEVELOPMENT SITE (SITE)
The specific tract of land for which a regulated activity is proposed.
DIFFUSED DRAINAGE
See "sheet flow."
DIRECT RECHARGE BMP
A BMP which directs runoff to an underground infiltration surface. Examples include infiltration trenches, seepage beds, and dry wells such that nearly all runoff becomes recharge to groundwater.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the use of private land for stormwater management purposes.
DRAINAGE PLAN
The documentation of the proposed stormwater quantity and quality management controls to be used for a given development site, including a BMP operations and maintenance plan, the contents of which are established in § 415-24.
EARTH-DISTURBANCE ACTIVITY
A construction or other human activity which disturbs the surface of the land, including, but not limited to, clearing and grubbing, grading, excavations, embankments, land development, agricultural plowing or tilling, timber harvesting activities, road maintenance activities, mineral extraction, and the moving, depositing, stockpiling, or storing of soil, rock or earth materials.
EROSION
The removal of soil particles by the action of water, wind, ice, or other geological agents.
EVAPOTRANSPIRATION BMP
A BMP which provides opportunity for runoff evaporation and transpiration by vegetation. Examples include bioretention and surface infiltration basins.
EXISTING USES
Those uses actually attained in the water body on or after November 28, 1975, whether or not they are included in the water quality standards (25 Pa. Code § 93.1).
FILL
Man-made deposits of natural soils or rock products and waste materials.
FILTER STRIPS
See "vegetated Buffers."
FREEBOARD
The incremental depth in a stormwater management structure, provided as a safety factor of design, above that required to convey the design runoff event.
GROUNDWATER RECHARGE
Replenishment of existing natural underground water supplies.
HOT-SPOT LAND USES
A land use or activity that generates higher concentrations of hydrocarbons, trace metals or other toxic substances than typically found in stormwater runoff. These land uses are listed in Appendix F.[1]
HYDROLOGIC ENGINEERING CENTER – HYDROLOGIC MODELING SYSTEM (HEC-HMS)
The computer-based hydrologic modeling technique developed by the United States Army Corps of Engineers and adapted to the Perkiomen Creek Headwaters for the Act 167 Plan. The model was "calibrated" to reflect actual flow values by adjusting key model input parameters.
HYDROLOGIC SOIL GROUP (HSG)
Soils are classified into four HSGs (A, B, C and D) to indicate the minimum infiltration rates, which are obtained for bare soil after prolonged wetting. The Natural Resources Conservation Service (NRCS) of the United States Department of Agriculture defines the four groups and provides a list of most of the soils in the United States and their group classification. The soils in the area of the development site may be identified from a soil survey report that can be obtained from local NRCS offices or conservation district offices. Soils become less permeable as the HSG varies from A to D.
IMPERVIOUS SURFACE (IMPERVIOUS COVER)
A surface which prevents the percolation of water into the ground.
INFILTRATION PRACTICE
A practice designed to allow runoff an opportunity to infiltrate into the ground, e.g., french drain, seepage pit, seepage trench, or bioretention area.
LAND DEVELOPMENT
Any of the following activities:
(1) 
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 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 of tenure; 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.
(2) 
A subdivision of land.
(3) 
Except that the following activities shall not be considered land development:
(a) 
The conversion of an existing single-family detached dwelling or single-family semidetached dwelling into not more than three residential units, unless such units are intended to be a condominium;
(b) 
The addition of an accessory building, including farm buildings, on a lot or lots subordinate to an existing principal building.
LANDOWNER
The legal or beneficial owner or owners of land including the holder of an option or contract to purchase (whether or not such option or contract is subject to any condition), a lessee if they are authorized under the lease to exercise the rights of the landowner, or other person having a proprietary interest in land.
LOCAL RUNOFF CONVEYANCE FACILITIES
Any natural channel or man-made conveyance system which has the purpose of transporting runoff from the site to the main stem.
LOW-IMPACT DEVELOPMENT
A development approach that promotes practices that will minimize post-development runoff rates and volumes, thereby minimizing needs for artificial conveyance and storage facilities. Site design practices include preserving natural drainage features, minimizing impervious surface area, reducing the hydraulic connectivity of impervious surfaces and protecting natural depression storage.
MAIN STEM (MAIN CHANNEL)
Any stream segment or other conveyance used as a reach in the Perkiomen Creek Headwaters hydrologic model.
MANNING EQUATION (MANNING FORMULA)
A method for calculation of velocity of flow (e.g., feet per second) and flow rate (e.g., cubic feet per second) in open channels based upon channel shape, roughness, depth of flow and slope. "Open channels" may include closed conduits so long as the flow is not under pressure.
MARYLAND STORMWATER DESIGN MANUAL
A stormwater design manual written by the Maryland Department of the Environment and the Center for Watershed Protection. As of January 2004, the manual can be obtained through the following web site: www.mde.state.md.us.
MINIMUM DISTURBANCE/MINIMUM MAINTENANCE PRACTICES (MD/MM)
Site design practices in which careful limits are placed on site clearance prior to development allowing for maximum retention of existing vegetation (woodlands and other), minimum disturbance and compaction of existing soil mantle and minimum site application of chemicals post development. Typically, MD/MM includes disturbance setback criteria from buildings as well as related site improvements such as walkways, driveways, roadways, and any other improvements. These criteria may vary by community context as well as by type of development being proposed. Additionally, MD/MM shall include provisions (e.g., deed restrictions, conservation easements) to protect these areas from future disturbance and from application of fertilizers, pesticides, and herbicides.
MUNICIPALITY
Upper Hanover Township, Montgomery County, Pennsylvania.
NPDES
National Pollutant Discharge Elimination System.
NRCS
Natural Resources Conservation Service, United States Department of Agriculture (formerly the Soil Conservation Service).
OIL/WATER SEPARATOR
A structural mechanism designed to remove free oil and grease (and possibly solids) from stormwater runoff.
OUTFALL
"Point source" as described in 40 CFR 122.2 at the point where the municipality's storm sewer system discharges to surface waters of the commonwealth.
PEAK DISCHARGE
The maximum rate of flow of stormwater runoff at a given location and time resulting from a specified storm event.
PERSON
An individual, partnership, public or private association or corporation, firm, trust, estate, municipality, governmental unit, public utility or any other legal entity whatsoever which is recognized by law as the subject of rights and duties.
POINT SOURCE
Any discernible, confined and discrete conveyance, including, but not limited to, any pipe, ditch, channel, tunnel or conduit from which stormwater is or may be discharged, as defined in state regulations at 25 Pa. Code § 92.1.
PUBLIC WATER SUPPLIER
A person who owns or operates a public water system.
PUBLIC WATER SYSTEM
A system which provides water to the public for human consumption which has at least 15 service connections or regularly serves an average of at least 25 individuals daily at least 60 days out of the year. (See 25 Pa. Code Chapter 109.)
RATIONAL METHOD
A method of runoff calculation using a standardized runoff coefficient, acreage of tract, and rainfall intensity that is determined by return period and by the time necessary for the entire tract to contribute runoff.
REACH
Any of the natural or man-made runoff conveyance channels used for watershed runoff modeling purposes to connect the subareas and transport flows downstream.
REGULATED ACTIVITIES
Any earth-disturbance activities or any activities that involve the alteration or development of land in a manner that may affect stormwater runoff and that are governed by this chapter as specified in § 415-5.
REGULATED EARTH-DISTURBANCE ACTIVITY
Activity involving earth disturbance, other than agricultural plowing and tilling, subject to regulation under 25 Pa. Code 92, 25 Pa. Code 102, or the Clean Streams Law.[2]
RELEASE RATE
The percentage of the predevelopment peak rate of runoff for a development site to which the post-development peak rate of runoff must be controlled to avoid peak flow increases throughout the watershed.
RETENTION BASIN
A structure in which stormwater is stored and not released during the storm event. Retention basins do not typically have an outlet to other downstream conveyance features such as channels, storm sewer, or other surface waters. Generally, these features empty via recharge and must infiltrate stored water in no more than four days. These features may have an emergency spillway or other overflow device for large events.
RETURN PERIOD
The average interval in years over which an event of a given magnitude can be expected to recur. For example, the twenty-five-year return period rainfall or runoff event would be expected to recur on the average once every 25 years.
ROAD MAINTENANCE
Earth-disturbance activities within the existing road cross section such as grading and repairing existing unpaved road surfaces, cutting road banks, cleaning or clearing drainage ditches and other similar activities.
RUNOFF
That part of precipitation which flows over the land.
SEDIMENT TRAPS/CATCH BASIN SUMPS
Chambers which provide storage below the outlet in a storm inlet to collect sediment, debris and associated pollutants, typically requiring periodic cleanout.
SEEPAGE PIT/SEEPAGE TRENCH
An area of excavated earth filled with loose stone or similar material and into which surface water is directed for infiltration into the ground.
SEPARATE STORM SEWER SYSTEM
A conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels or storm drains) primarily used for collecting and conveying stormwater runoff.
SHEET FLOW
Stormwater runoff flowing in a thin layer over the ground surface.
SOIL-COVER-COMPLEX METHOD
A method of runoff computation developed by NRCS which is based upon relating soil type and land use/cover to a runoff parameter called a "curve number."
SPILL PREVENTION AND RESPONSE PROGRAM
A program that identifies procedures for preventing and, as needed, cleaning up potential spills and makes such procedures known and the necessary equipment available to appropriate personnel.
STATE WATER QUALITY REQUIREMENTS
As defined under state regulations, protection of designated and existing uses (See 25 Pa. Code Chapters 93 and 96.), including:
(1) 
Each stream segment in Pennsylvania has a "designated use," such as "cold-water fishes" or "potable water supply," which is listed in Chapter 93. These uses must be protected and maintained, under state regulations.
(2) 
"Existing uses" are those attained as of November 1975, regardless whether they have been designated in Chapter 93. Regulated earth-disturbance activities must be designed to protect and maintain existing uses and maintain the level of water quality necessary to protect those uses in all streams, and to protect and maintain water quality in special protection streams.
(3) 
Water quality involves the chemical, biological and physical characteristics of surface water bodies. After regulated earth-disturbance activities are complete, these characteristics can be impacted by addition of pollutants such as sediment, and changes in habitat through increased flow volumes and/or rates as a result of changes in land surface area from those activities. Therefore, permanent discharges to surface waters must be managed to protect the stream bank, streambed and structural integrity of the waterway, to prevent these impacts.
STORAGE INDICATION METHOD
A method of routing or moving an inflow hydrograph through a reservoir or detention structure. The method solves the mass conservation equation to determine an outflow hydrograph as it leaves the storage facility.
STORM DRAINAGE PROBLEM AREAS
Areas which lack adequate stormwater collection and/or conveyance facilities and which present a hazard to persons or property as determined by the municipality.
STORM SEWER
A system of pipes or other conduits which carries intercepted surface runoff, street water and other wash waters, or drainage, but excludes domestic sewage and industrial wastes.
STORMWATER
The surface runoff generated by precipitation reaching the ground surface.
STORMWATER FILTERS
Any number of structural mechanisms such as multi-chamber catch basins, sand/peat filters, sand filters, and so forth which are installed to intercept stormwater flow and remove pollutants prior to discharge. Typically, these systems require periodic maintenance and cleanout.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff adopted by Montgomery County for the Perkiomen Creek Headwaters Watershed as required by the Act of October 4, 1978, P.L. 864 (Act 167), as amended, and known as the "Stormwater Management Act."[3]
STREAM
A watercourse.
SUBAREA
The smallest unit of watershed breakdown for hydrologic modeling purposes for which the runoff control 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 and new street or easement of access or any residential dwelling, shall be exempted.
SURFACE WATERS OF THE COMMONWEALTH
Any and all rivers, streams, creeks, rivulets, impoundments, ditches, watercourses, storm sewers, lakes, dammed water, wetlands, ponds, springs and all other bodies or channels of conveyance of surface water, or parts thereof, whether natural or artificial, within or on the boundaries of this commonwealth.
SWALE
A low-lying stretch of land which gathers or carries surface water runoff. See also "vegetated swale."
TRASH/DEBRIS COLLECTORS
Racks, screens or other similar devices installed in a storm drainage system to capture coarse pollutants (trash, leaves, etc.).
VEGETATED BUFFERS
Gently sloping areas that convey stormwater as sheet flow over a broad, densely vegetated earthen area, possibly coupled with the use of level spreading devices. As water quality BMPs, vegetated buffers serve to filter pollutants from runoff and promote infiltration, Vegetated buffers should be situated on minimally disturbed soils, have low-flow velocities and extended residence times. Vegetated buffers may be, but are not restricted to, use in riparian (streamside) conditions.
VEGETATED ROOFS
Vegetated systems installed on roofs that generally consist of a waterproof layer, a root-barrier, drainage layer (optional), growth media, and suitable vegetation. Vegetated roofs store and eventually evapotranspirate the collected rooftop rainfall; overflows may be provided for larger storms.
VEGETATED SWALES
Vegetated earthen channels designed to convey and possibly treat stormwater. As water quality BMPs, these are broad, shallow, densely vegetated, earthen channels designed to treat stormwater through infiltration, evapotranspiration, and sedimentation. Swales should be gently sloping with low-flow velocities to prevent erosion. Check dams may be added to enhance performance.
WAIVER REQUEST
A written request for a waiver alleging that the provisions of this chapter inflict unnecessary hardship upon the applicant. A waiver does not apply to and is not available from the water quality provisions of this chapter and should not be granted.
WATERCOURSE
Any channel of conveyance of surface water having defined bed and banks, whether natural or artificial, with perennial or intermittent flow.
WATER QUALITY INSERTS
Any number of commercially available devices that are inserted into storm inlets to capture sediment, oil, grease, metals, trash, debris, etc.
WATER QUALITY VOLUME (WQV)
The increase in volume on a development site associated with a two-year, twenty-four-hour storm event.
WATERSHED
The entire region or area drained by a river or other body of water, whether natural or artificial.
WET DETENTION BASINS/PONDS
Basins that provide for necessary stormwater storage as well as a permanent pool of water. To be successful, wet ponds must have adequate natural hydrology (both runoff inputs as well as soils and water table which allow for maintenance of a permanent pool of water) and must be able to support a healthy aquatic community so as to avoid creation of mosquito and other health and nuisance problems.
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, fens, and similar areas.
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.
[2]
Editor's Note: See 35 P.S. § 691.1 et seq.
[3]
Editor's Note: See 32 P.S. 680.1 et seq.