For the purposes of this chapter, the 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 the feminine gender; and words of feminine gender include the 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 words "shall" and "must" are mandatory; the words "may" and "should" are permissive.
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 the natural processes at a rate greater than would occur because of the natural process alone.
ACT 167
The Storm Water Management Act, Act of October 4, 1978, P.L. 864, No. 167, as amended by the Act of May 24, 1984, No. 63, 32 P.S. §§ 680.1 et seq.
AGRICULTURAL ACTIVITY
Activities associated with agriculture such as agricultural cultivation, agricultural operation, and animal heavy use areas. This includes the work of producing crops and raising livestock including tillage, land clearing, plowing, disking, harrowing, planting, harvesting crops, or pasturing and raising of livestock and installation of Conservation Practices. Except for high tunnels that are exempt pursuant to the provisions of Act 15 of 2018,[1] construction of new buildings or impervious areas are not considered an agricultural activity.
ANIMAL CONCENTRATION (HEAVY USE) AREAS
A barnyard, feedlot, loafing area, exercise lots, or other similar animal confinement areas that will not maintain a growing crop, or where deposited manure nitrogen is in excess of crop needs, but excluding areas managed as pastures or other cropland, and pasture access ways, if they do not cause direct flow of nutrients to surface water or groundwater.
APPLICANT
A landowner, developer or other person who has filed an application for development or for approval to engage in any regulated earth disturbance activity at a project site in the Township.
AS BUILT DRAWINGS
Drawings showing the stormwater management system of a site as built, created after the completion of construction and intended for use as a permanent record of the stormwater management system.
BMP (BEST MANAGEMENT PRACTICE)
Activities, facilities, designs, measures or procedures used to manage stormwater impacts from regulated development activities to meet state water quality requirements, to promote groundwater recharge and to otherwise meet the purposes of this chapter. BMPs include, but are not limited to, infiltration, filter strips, low-impact design, bioretention, wet ponds, permeable paving, grassed swales, forested buffers, sand filters and detention basins.
CHANNEL
A perceptible natural or artificial waterway which periodically or continuously contains moving water or which forms a connecting link between two bodies of water, having a definite bed and banks which confine the water.
CHAPTER 102
Title 25 Pa. Code Chapter 102, Erosion and Sediment Control.
CHAPTER 105
Title 25 Pa. Code Chapter 105, Dam Safety and Water Management.
COMBINED SEWER SYSTEM
A sewer system designed to serve as both a sanitary sewer and storm sewer.
CONSERVATION DISTRICT
The Westmoreland Conservation District (WCD), as defined in Section 3(c) of the Conservation District Law [3 P.S. § 851(c)] that has the authority under a delegation agreement executed with DEP to administer and enforce all or a portion of the regulations promulgated under 25 Pa. Code Chapter 102.
CONSERVATION PLAN
A plan written by an NRCS- or SCS-certified planner that identifies conservation practices and includes site-specific BMPs for agricultural plowing or tilling activities and animal concentration areas.
CONSERVATION PRACTICES
Practices installed on agricultural lands to improve farmland, soil and/or water quality which have been identified in a current conservation plan.
CONVEYANCE
A. 
Any structure that carries a flow.
B. 
The ability of a pipe, culvert, swale or similar facility to carry the peak flow from the design storm.
CSO, COMBINED SEWER OVERFLOW
An intermittent flow or other untreated discharge from a municipal combined sewer system (including domestic, industrial and commercial wastewater and stormwater) which results from a flow in excess of the dry weather carrying capacity of the system.
CULVERT
A closed conduit for the free passage of surface drainage under a highway, railroad, canal or other embankment.
DEMONSTRATED EQUIVALENCY
A stormwater management project on an alternative site or sites within the same watershed as the proposed development that will provide equal or better achievement of the purpose of the ordinance and will not substantially or permanently impair the appropriate use or development of adjacent property. Examples include: stream bank stabilization, creation or enhancement of riparian buffers, removal of existing impervious surfaces and establishment of "green" easements, installation of stormwater management and water quality facilities, etc.
DEP
The Pennsylvania Department of Environmental Protection.
DESIGN CRITERIA
A. 
Engineering guidelines specifying construction details and materials.
B. 
Objectives, results or limits which must be met by a facility, structure or process in performance of its intended functions.
DESIGN STORM
See "storm frequency."
DETENTION
The slowing, dampening or attenuating of runoff flows entering the natural drainage pattern or storm drainage system by temporarily holding water on a surface area in a detention basin or within the drainage system.
DETENTION BASIN
A pond, basin, reservoir or underground system constructed to impound or retard surface runoff temporarily.
DEVELOPER
A person that seeks to undertake or undertakes the activities associated with changes in land use or seeks to undertake or undertakes any regulated earth disturbance activities at a project site in the Township. The term "developer" includes, but is not limited to, the term subdivider, owner, builder or another person with a similar interest in the project, even though the person involved in successive stages of a project may change or vary.
DEVELOPMENT
An "earth disturbance activity," as herein defined, and any activity, construction, alteration, change in land use or practice that affects stormwater runoff characteristics. The term also includes redevelopment.
DEVELOPMENT SITE
The specific tract of land where any development or earth disturbance activities in the Township are planned, conducted, undertaken or maintained.
DISCHARGE
The flow or rate of flow from a canal, conduit, channel or other hydraulic structure.
DISTURBED AREA
A land area where an earth disturbance activity is occurring or has occurred.
DRAINAGE
In general, the removal of surface water from a given area commonly applied to surface water and groundwater.
DRAINAGE AREA
Any of the following activities:
A. 
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").
B. 
The area served by a sewer system receiving stormwater and surface water, or by a watercourse.
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, road maintenance, land development, building construction, oil and gas activities, well drilling, mineral extraction, and the moving, depositing, stockpiling, or storing of soil, rock or earth materials.
ENCROACHMENT
Any structure or activity which in any manner changes, expands or diminishes, the course, current or cross-section of any watercourse, floodway or body of water.
EROSION
The process by which land, including channels, is worn away by water, wind, or chemical action.
EROSION AND SEDIMENT CONTROL PLAN
A plan for a project site which identifies BMPs to minimize accelerated erosion and sedimentation of land.
EROSION CONTROL
The application of measures to reduce erosion of land surfaces.
EXISTING CONDITION
The dominant land cover during the five-year period immediately preceding a proposed regulated activity.
FEMA
Federal Emergency Management Agency.
FLOODPLAIN
Any land area susceptible to inundation by water from any natural source or delineated by applicable FEMA maps and studies as being a special flood hazard area. Also includes areas that comprise Group 13 Soils, as listed in Appendix A of the Pennsylvania DEP Technical Manual for Sewage Enforcement Officers (as amended or replaced from time to time by DEP).
FLOODWAY
The channel of the watercourse and those portions of the adjoining floodplains that are reasonably required to carry and discharge the one-hundred-year flood. Unless otherwise specified, the boundary of the floodway is as indicated on maps and flood insurance studies provided by FEMA. In an area where no FEMA maps or studies have defined the boundary of the one-hundred-year floodway, it is assumed — absent evidence to the contrary — that the floodway extends from the stream to 50 feet from the top of the bank of the stream.
FOREST MANAGEMENT/TIMBER OPERATIONS
Planning and activities necessary for the management of forestland. These include conducting a timber inventory, preparation of forest management plans, silvicultural treatment, cutting budgets, logging road design and construction, timber harvesting, site preparation, and reforestation.
GREEN INFRASTRUCTURE
Systems and practices that use or mimic natural processes to infiltrate, evapotranspire, or reuse stormwater on the site where it is generated.
GROUND COVER
Materials and/or vegetation covering the ground surface.
GROUNDWATER
Subsurface water occupying the saturation zone, from which wells and springs are fed.
GROUNDWATER RECHARGE
Replenishment of existing natural underground water supplies.
HIGH TUNNEL
A structure which meets the following:
A. 
Is used for the production, processing, keeping, storing, sale or shelter of an agricultural commodity as defined in Section 2 of the Act of December 19, 1974 (P.L. 973, No. 319), known as the "Pennsylvania Farmland and Forestland Assessment Act of 1974," 72 P.S. § 5490.2, or for the storage of agricultural equipment and supplies; and
B. 
Is constructed with the following features:
(1) 
A metal, wood or plastic frame;
(2) 
When covered, has plastic, woven textile or other flexible covering; and
(3) 
Has a floor made of soil, crushed stone, matting, pavers or a floating concrete slab.
HOT SPOTS
Areas where land use or activities generate highly contaminated runoff, with concentrations of pollutants that are higher than those typically found in stormwater (e.g., vehicle salvage yards and recycling facilities, vehicle fueling stations, fleet storage areas, vehicle equipment and cleaning facilities, vehicle service and maintenance facilities, and certain industrial/commercial activity areas).
HYDROLOGIC SOIL GROUP (HSG)
Soils whose infiltration rates vary widely and are affected by subsurface permeability as well as surface intake rates. Soils of this type are classified into four HSGs (A, B, C, and D) according to their minimum infiltration rate, which is obtained for bare soil after prolonged wetting. The NRCS defines the four groups and provides a list of most of the soils in the United States and their group classification. Soils in the development site may be identified from a soil survey report obtained from local NRCS offices or conservation district offices. Soils become less permeable as the HSG varies from A to D (NRCS1,2).
IMPERVIOUS SURFACE
A surface that prevents the infiltration of water into the ground. Impervious surfaces (or areas) shall include, but not be limited to: roofs, additional indoor living spaces, patios, garages, storage sheds, and similar structures; and any new streets or sidewalks. Decks, parking areas, gravel areas, and driveway areas are counted as impervious areas if they directly prevent infiltration.
INFILTRATION
Any of the following activities:
A. 
The flow or movement of water through the interstices or pores of a soil or other porous medium.
B. 
The absorption of liquid by the soil.
LAND DEVELOPMENT
Any of the following activities:
A. 
The improvement of one lot or two or more contiguous lots, tracts or parcels of land for any purpose involving:
(1) 
A group of two or more 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.
(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.
LAND DISTURBANCE
Any activity involving the changing, grading, transportation, fill and any other activity which causes land to be exposed to the danger of erosion.
LOW-IMPACT DEVELOPMENT (LID)
Site design approaches and small-scale stormwater management practices that promote the use of natural systems for infiltration, evapotranspiration, and reuse of rainwater. LID can be applied to new development, urban retrofits, and revitalization projects. LID utilizes design techniques that infiltrate, filter, evaporate, and store runoff close to its source. Rather than rely on costly large-scale conveyance and treatment systems, LID addresses stormwater through a variety of small, cost-effective landscape features located on site.
MAINTENANCE
The upkeep necessary for efficient operation of physical properties.
MS4 (MUNICIPAL 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):
A. 
Owned or operated by a state, city, town, township, county, parish, district, association, authority or other public body (created by or pursuant to state law), including special districts under state law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under Section 208 of the Clean Water Act that discharges into waters of the United States;
B. 
Designed or used for collecting or conveying stormwater;
C. 
Which is not a combined sewer; and
D. 
Which is not part of a publicly owned treatment works (POTW) as defined at 40 CFR 122.2.
MUNICIPALITIES PLANNING CODE
Act 247 of 1968, as amended by Act 170 of 1988, 53 P.S. § 10101 et seq.
MUNICIPALITY
Unity Township, Westmoreland County, Pennsylvania.
NATIVE VEGETATION
Plant species that have historically grown in Pennsylvania and are not invasive species, controlled plants or noxious weeds as defined by PA DCNR, or PA Department of Agriculture.
NATURAL STORMWATER RUNOFF REGIME
A watershed where natural surface configurations, runoff characteristics and defined drainage conveyances have attained the conditions of equilibrium.
NPDES
National Pollutant Discharge Elimination System, the federal government's system for issuance of permits under the Clean Water Act, which is delegated to DEP in Pennsylvania.
NRCS
Natural Resources Conservation Service (previously Soil Conservation Service).
OUTFALL
A "point source" as described in 40 CFR 122.2 at the point where the Township storm sewer system discharges to surface waters of the commonwealth. Also, the point, location or structure where drainage discharges from a sewer, drain or other conduit as well as the conduit leading to the ultimate discharge point.
OUTLET CONTROL STRUCTURE
The means of controlling the relationship between the head water elevation and the discharge, placed at the outlet or downstream end of any structure through which water may flow.
OVERLAND FLOODING
Flooding that occurs for a variety of reasons all stemming from excessive stormwater runoff, including too much rain in too little time, added impervious development, change in land use, malfunction or clogging of existing stormwater systems.
PEAK DISCHARGE
The maximum rate of stormwater runoff from a specific storm event.
PEAK FLOW
Maximum flow.
PENNSYLVANIA DEP
Pennsylvania Department of Environmental Protection.
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, firm, trust, estate, municipality, governmental unit, public utility or any other legal entity whatsoever which is recognized by law as having rights and duties. Whenever used in any section prescribing or imposing a penalty, the term "person" shall include the members of a partnership, the officers, members, servants and agents of an association, officers, agents and servants of a corporation, and the officers of a municipality or county, but shall exclude any department, board, bureau or agency of the commonwealth.
PERVIOUS AREA
Any material or surface that allows water to pass through at a rate equal to or greater than natural ground cover.
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.[2]
POLLUTANT REDUCTION PLAN (PRP)
A plan required by the MS4 permit to calculate existing pollutants of concern and the minimum reduction in loading from stormwater discharges, and to select the best management practices to achieve the minimum reductions.
PROJECT SITE
The specific area of land where any development or regulated earth disturbance activities in the Township are planned, conducted, undertaken or maintained.
QUALIFIED PROFESSIONAL
Any person licensed by the Pennsylvania Department of State or otherwise qualified under Pennsylvania law to perform the work required by this chapter.
REDEVELOPMENT
Earth disturbance activities on land which has previously been disturbed or developed.
REGULATED DEVELOPMENT ACTIVITY
Any earth disturbance activities, or any activities that involve the change of land cover, alteration or development of land in a manner that may affect stormwater runoff as listed in the Regulated Development Activity Table. This includes earth disturbance on any portion of, part, or during any stage of a larger common plan of development. With regard to road maintenance activities, the term only includes activities involving one acre or more of earth disturbance. Reference should be made to the Regulated Development Activity Table in Article III of this chapter.
RELEASE RATE
The percentage of existing conditions peak rate of runoff from a site or subarea to which the proposed conditions peak rate of runoff must be reduced to protect downstream areas.
RELEASE RATE PERCENTAGE
The watershed factor determined by comparing the maximum rate of runoff from a subbasin to the contributing rate of runoff to the watershed peak rate at specific points of interest.
RESOURCE EXTRACTION
Any activity that involves withdrawing materials from the natural environment.
RETENTION BASIN
A pond or basin, usually enclosed by artificial dikes, that is used to retard stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate.
RETENTION VOLUME/REMOVED RUNOFF
The volume of runoff that is captured and not released directly into the surface waters of this commonwealth during or immediately after a storm event.
RETURN PERIOD
The average interval in years over which an event of a given magnitude can be expected to recur.
RIPARIAN BUFFER
A permanent area of native vegetation, including herbaceous material, shrubs and/or trees, located adjacent to streams, lakes, ponds and wetlands.
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.
RUNOFF CHARACTERISTICS
The surface components of any watershed which affect the rate, amount and direction of stormwater runoff. These may include, but are not limited to, vegetation, soils, slopes and man-made landscape alterations.
RURAL AREA
All population, housing and territory not included within an urban, or urbanized, area as determined from the latest U.S. Census Bureau data.
SALDO
Chapter 104, Subdivision and Land Development, of the Code of Unity Township, as may be amended from time to time hereafter.
SEDIMENT
Mineral or organic solid material that is being transported or has been moved from its site of origin by air, water or ice and has come to rest.
SEDIMENTATION
The process by which mineral or organic matter is accumulated or deposited by moving water, wind or gravity.
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. Reference may be made to "MS4" above for additional details.
SMALL PROJECT
Regulated development activities that, measured on a cumulative basis from five years prior to the application, create additional impervious areas of more than 1,000 square feet and less than 3,000 square feet or involve earth disturbance activity of an area less than 5,000 square feet and do not involve the alteration of stormwater facilities or watercourses.
STATE WATER QUALITY REQUIREMENTS
As defined under state regulations, protection of designated and existing uses (see 25 Pa. Code Chapters 93 and 96), including:
A. 
Each stream segment in Pennsylvania has a "designated use," such as "cold water fishery" or "potable water supply," which are listed in 25 Pa. Code Chapter 93. These uses must be protected and maintained under state regulations.
B. 
"Existing uses" are those attained as of November 1975, regardless whether they have been designated in 25 Pa. Code 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.
C. 
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 FACILITY
Any surface or sub-surface facility that stores stormwater runoff, see "detention basin" and "retention basin."
STORM FREQUENCY
The average interval in years over which a storm event of a given precipitation volume can be expected to occur. 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. Also see "return period".
STORM SEWER
A sewer that carries intercepted surface runoff, street water and other drainage but excludes domestic sewage and industrial waste.
STORMWATER
Drainage runoff from the surface of the land resulting from precipitation or snow or ice melt.
STORMWATER COLLECTION SYSTEMS
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 MANAGEMENT FACILITY
A constructed measure for detention, retention, infiltration and water quality treatment of stormwater runoff.
STORMWATER MANAGEMENT PERFORMANCE DISTRICT
An area designated by the Watershed Stormwater Performance District Map which includes standards for stormwater rate, volume and water quality. Refer to Appendix A.[3]
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff rate, volume and water quality as required by the Storm Water Management Act, 32 P.S. § 680.1 et seq.
SUBDIVISION
As defined in the Pennsylvania Municipalities Planning Code, Act of July 31, 1968, P.L. 805, No. 247, 53 P.S. § 10101 et seq., as amended.
SWALE
A low-lying stretch of land which gathers or carries surface water runoff.
URBAN OR URBANIZED AREA
An area that is densely populated and/or is significantly built upon with buildings, pavement, and other man-made features. Urban (or urbanized) areas are defined in the latest U.S. Census Bureau data.
USDA
United States Department of Agriculture.
WATERCOURSE
A channel or conveyance of surface water, such as a run, stream or creek, having defined bed and banks, whether natural or artificial, with perennial or intermittent flow.
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.
WATERSHED
The entire region or area drained by a river or other body of water whether natural or artificial. A "designated watershed" is an area delineated by the Pennsylvania DEP and approved by the Environmental Quality Board for which counties are required to develop watershed stormwater management plans.
WATERSHED STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff throughout a designated watershed as required by the Pennsylvania Storm Water Management Act (Act 167), 32 P.S. § 680.1 et seq.
WETLAND
Areas that are inundated or saturated by surface water 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.
[1]
Editor's Note: See 32 P.S. § 680.1 et seq.
[2]
Editor's Note: The term "point source" is defined in 25 Pa. Code § 96.1.
[3]
Editor's Note: Appendix A, Stormwater Performance District Maps, is included as an attachment to this chapter.