For the purposes of this chapter, certain terms and words used herein shall be interpreted as follows:
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.
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.
The words "shall" and "must" are mandatory; the words "may" and "should" are permissive.
These definitions do not necessarily reflect the definitions contained in pertinent regulations or statutes, and are intended for this chapter only.
As used in this chapter, the following terms shall have the meanings indicated:
- ACT 167
- The municipality is empowered to regulate land use activities that affect runoff and surface water and groundwater quality and quantity by the authority of the Act of October 4, 1978, P.L. 864 (Act 167), 32 P.S. § 680.1 et seq., as amended, the "Stormwater Management Act."
- AGRICULTURAL ACTIVITY
- Activities associated with agriculture such as agricultural cultivation, agricultural operation, and animal heavy use areas. This includes the work of producing crops, including tillage, land clearing, plowing, disking, harrowing, planting, harvesting crops or pasturing and raising of livestock and installation of conservation measures. Construction of new buildings or impervious area is not considered an agricultural activity.
- A landowner, developer, or other person who has filed an application to the municipality for approval to engage in any regulated activity at a project site in the municipality.
- AUTHORIZED AGENT
- Any person responsible for a property, such as a property manager, property management company, and/or any agent acting on behalf of the owner. This shall include but shall not be limited to persons who complete and submit an application on behalf of the property owner.
- BEST MANAGEMENT PRACTICE (BMP)
- Activities, facilities, designs, measures, or procedures used to manage stormwater impacts from regulated activities, to meet state water quality requirements, to promote groundwater recharge, and to otherwise meet the purposes of this chapter. Stormwater BMPs are commonly grouped into one of two broad categories or measures: "structural" or "nonstructural." In this chapter, nonstructural BMPs or measures refer to operational and/or behavior-related practices that attempt to minimize the contact of pollutants with stormwater runoff, whereas structural BMPs or measures are those that consist of a physical device or practice that is installed to capture and treat stormwater runoff. Structural BMPs include, but are not limited to, a wide variety of practices and devices, from large-scale retention ponds and constructed wetlands, to small-scale underground treatment systems, infiltration facilities, filter strips, low-impact design, bioretention, wet ponds, permeable paving, grassed swales, riparian or forested buffers, sand filters, detention basins, and manufactured devices. Structural stormwater BMPs are permanent appurtenances to the project site.
- CONSERVATION DISTRICT
- A conservation district, 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.
- The Pennsylvania Department of Environmental Protection.
- 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. Also see "return period."
- DESIGNATED PLAN REVIEWER
- A qualified professional as defined herein, or organization such as the Allegheny County Conservation District, that has been designated by the municipality to be the reviewer of SWM site plans for the municipality, and shall be understood to be the reviewer where indicated as the municipality within this chapter.
- DETENTION BASIN
- An impoundment designed to collect and retard stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate. Detention basins are designed to drain completely in a designated period after a rainfall event, and to become dry until the next rainfall event.
- DETENTION VOLUME
- The volume of runoff that is captured and released into the waters of the Commonwealth at a controlled rate.
- DEVELOPMENT SITE (SITE)
- See "project site."
- DISTURBED AREA
- An unstable land area where an earth disturbance activity is occurring or has occurred.
- 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; building construction; and the moving, depositing, stockpiling, or storing of soil, rock, or earth materials.
- The natural process by which the surface of the land is worn away by water, wind, or chemical action.
- EXISTING CONDITION
- The dominant land cover during the five-year period immediately preceding a proposed regulated activity.
- Federal Emergency Management Agency.
- 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).
- 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.
- Water beneath the earth's surface that supplies wells and springs and is within the saturated zone of soil and rock.
- GROUNDWATER RECHARGE
- The replenishment of existing natural underground water supplies from precipitation or overland flow.
- HYDROLOGIC SOIL GROUP (HSG)
- Infiltration rates of soils vary widely and are affected by subsurface permeability as well as surface intake rates. Soils are classified into 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. 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 pervious as the HSG varies from A to D (NRCS, ).
- IMPERVIOUS SURFACE (IMPERVIOUS AREA)
- 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, and driveway areas are counted as impervious areas if they directly prevent infiltration.
- Movement of surface water into the soil, where it is absorbed by plant roots, evaporated into the atmosphere, or percolated downward to recharge groundwater.
- INVASIVE SPECIES
- DCNR defines invasive plants as those species that are not native to the state, grow aggressively, and spread and displace native vegetation. (See http://www.dcnr.state.pa.us/cs/groups/public/documents/document/dcnr_010314.pdf for a list of invasive species.)
- LAND DEVELOPMENT (DEVELOPMENT)
- Inclusive of any or all of the following meanings:
- (1) The improvement of one lot or two or more contiguous lots, tracts, or parcels of land for any purpose involving:
- (2) Any subdivision of land.
- (3) Development in accordance with Section 503(1.1) of the Pennsylvania Municipalities Planning Code.
- 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.
- Borough of Wilkinsburg, Allegheny County, Pennsylvania.
- NATIVE VEGETATION
- Plant species that have historically grown in Pennsylvania and are not "invasive species," as defined herein.
- USDA Natural Resources Conservation Service (previously SCS).
- PEAK DISCHARGE
- The maximum rate of stormwater runoff from a specific storm event.
- PERVIOUS AREA
- Any area not defined as impervious.
- PROJECT SITE
- The specific area of land where any regulated activities in the municipality are planned, conducted, or maintained.
- QUALIFIED PROFESSIONAL
- Any person licensed by the Pennsylvania Department of State or otherwise qualified under Pennsylvania law to perform the work required by this chapter.
- REGULATED ACTIVITIES
- Any earth disturbance activities or any activities that involve the alteration or development of land in a manner that may affect stormwater runoff.
- REGULATED EARTH DISTURBANCE ACTIVITY
- Activity involving earth disturbance subject to regulation under 25 Pa. Code Chapter 92a, 25 Pa. Code Chapter 102, or the Clean Streams Law.
- 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 DISTRICT
- A watershed or portion of a watershed for which a release rate has been established by an adopted Act 167 Stormwater Management Plan.
- 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 occur one time. For example, the twenty-five-year return period rainfall would be expected to occur on average once every 25 years; or, stated in another way, the probability of a twenty-five-year storm occurring in any one year is 0.04 (i.e., a four-percent chance).
- RIPARIAN BUFFER
- A permanent vegetated area of trees and shrubs located adjacent to streams, lakes, ponds and wetlands.
- Any part of precipitation that flows over the land.
- Soils or other materials transported by surface water as a product of erosion.
- 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.
- Drainage runoff from the surface of the land resulting from precipitation or snow or ice melt.
- 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 facilities.
- STORMWATER MANAGEMENT SITE PLAN
- The plan prepared by the developer or the developer's representative indicating how stormwater runoff will be managed at the development site in accordance with this chapter. "Stormwater management site plan" will be designated as "SWM site plan" throughout this chapter.
- A channel or conveyance of surface water having a defined bed and banks, whether natural or artificial, with perennial or intermittent flow.
- As defined in the Pennsylvania Municipalities Planning Code, Act of July 31, 1968, P.L. 805, No. 247.
- United States Department of Agriculture.
- See "stream."
- WATERS OF THIS 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 and underground water, or parts thereof, whether natural or artificial, within or on the boundaries of this Commonwealth.
- Region or land area drained by a river, watercourse, or other surface water of this Commonwealth to a downstream point.
- 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.
Reference: U.S. Department of Agriculture, National Resources Conservation Service (NRCS). National Engineering Handbook. Part 630: Hydrology, 1969-2001. Originally published as the National Engineering Handbook, Section 4: Hydrology. Available from the NRCS online at: http://www.nrcs.usda.gov/.
Reference: U.S. Department of Agriculture, National Resources Conservation Service. 1986. Technical Release 55: Urban Hydrology for Small Watersheds, 2nd Edition. Washington, D.C.
Editor's Note: See 53 P.S. § 10503(1.1).
Editor's Note: See 35 P.S. § 691.1 et seq.
Editor's Note: See 53 P.S. § 10101 et seq.