[Amended 9-9-2024 by Ord. No. 370]
As used in this chapter, the following terms shall have the meanings indicated:
AGRICULTURAL ACTIVITIESActivities 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.
ALTERATIONAs 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.
APPLICANTA landowner or developer who has filed an application for approval to engage in any regulated activities as defined in §
13-1.4 of this chapter.
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, stormwater structures, facilities and techniques to maintain or improve the water quality of surface runoff.
BUFFER AREAArea that is protected from development in order to prevent degradation of the water body or water quality.
CAPTURE DEPTHDepth of runoff captured from a given area and either allowed to evaporate, infiltrate, or be discharged through a spillway at a negligible rate.
CARBONATEA sediment formed by the organic or inorganic precipitation of mineral compounds characterized by the fundamental chemicalion CO3, the principal element in limestone and dolomite strata.
CHANNELA perceptible natural or artificial waterway that periodically or continuously contains moving water having a definite bed and banks that confine the water.
CLOSED OR UNDRAINED DEPRESSIONIn a karst geologic area, a distinct bowl-shaped depression in the land surface; size and amplitude are variable; drainage is internal. It differs from a sinkhole in that the ground surface is unbroken and usually occurs in greater density per unit area.
CREDITSA deduction from the required amount; in this chapter, implies reduction of required water quality volumes due to using a recommended practice.
DAMAn 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.
DEPThe Pennsylvania Department of Environmental Protection.
DESIGN STORMThe 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."
DESIGNEEThe agent of a Planning Commission and/or agent of the governing body involved with the administration, review or enforcement of any provisions of this chapter by contract or memorandum of understanding.
DETENTION BASINAn impoundment structure designed to manage stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate.
DETENTION VOLUMEThe volume of runoff that is captured and released into the waters of the commonwealth at a controlled rate.
DEVELOPERA 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. See also "project site."
DISTURBED AREAAn unslabilized land area where an earth disturbance activity is occurring or has occurred.
DOLOMITEA mineral consisting of calcium magnesium carbonate found as compact limestone; or limestone or marble rich in magnesium carbonate.
DOWNSLOPE PROPERTY LINEThat 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 FACILITYA stormwater management facility designed to transmit stormwater runoff and shall include streams, channels, swales, pipes, conduits, culverts, storm sewers, etc.
DRAINAGE EASEMENTA right granted by a landowner to a grantee, allowing the use of private land for stormwater management purposes.
DRAINAGEWAYThe natural or man-made path of surface water from a given area.
EARTH DISTURBANCE ACTIVITYA 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.
EROSIONThe movement of soil particles by the action of water, wind, ice, or other natural forces.
EXFILTRATIONThe process by which water or moisture moves from a subsurface trench, bed, or other feature into the subsoil. Exfiltration is best measured by a soil's percolation rate.
EXISTING IMPERVIOUS CONDITIONSA. The documented impervious condition as managed by the related stormwater controls required at the time the impervious area was established.
For the purposes of determining the existing impervious condition, any impervious added since 2006 without documented stormwater management shall be considered previous modeled as meadow in good condition. The existing impervious condition may be established utilizing the 2006 Centre County aerials, previously recorded land development plans, or as-built stormwater management plans to establish the documented existing condition.
FEMAFederal Emergency Management Agency.
FLOODA 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.
FLOODPLAINAny 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.
FLOODWAYThe channel of the watercourse and those portions of the adjoining floodplains that are reasonably required to carry and discharge the 100-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 100-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 OPERATIONSPlanning and activities necessary for the management of forestland. 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.
FREEBOARDA 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.
GRASSED WATERWAYA natural or constructed waterway, usually broad and shallow, covered with erosion-resistant grasses, used to conduct surface water from cropland.
GREEN INFRASTRUCTURESystems and practices that use or mimic natural processes to infiltrate, evapotranspire, or reuse stormwater on the site where it is generated.
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 (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 not counted as impervious areas if they do not prevent infiltration.
IMPOUNDMENTA retention or detention basin designed to retain stormwater runoff and release it at a controlled rate.
INFILTRATION RATEThe infiltration rate of a soil is related to the soil's final infiltration capacity and represents the rate at which water enters the soil/air interface at the top of the soil profile. Infiltration rates are measured in units of length/time.
INLETA 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.
INTERCEPTORA channel, berm, or dike constructed across a slope for the purpose of intercepting stormwater, reducing the velocity of flow, and diverting it to outlets where it may be disposed.
KARSTA type of topography that is formed over limestone, dolomite, or gypsum by bedrock solution and that is characterized by closed depressions or sinkholes, caves, and underground drainage (from AGI, Glossary of Geology, 1972).
LAND DEVELOPMENTInclusive of any or all of the following meanings:
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 buildings; or
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;
Development in accordance with Section 503(1.1) of the Pennsylvania Municipalities Planning Code.
LAND USEThe primary application employed in an area.
LAND/EARTH DISTURBANCEAny 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.
LIMESTONEA rock that, by accumulation of organic remains, consists mainly of calcium carbonate.
LINEAMENTSStraight or gently curved, lengthy features frequently expressed topographically as depressions or lines on the earth's surface. They can be more easily observed at a height of 100 meters or more and are usually found by researching aerial photographs or satellite photography. They are usually located in areas of faulting or in dense jointing along some rock stratigraphy.
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.
MAIN STEM (MAIN CHANNEL)Any stream segment or other runoff conveyance facility used as a reach in the Spring Creek hydrologic model.
MINIMUM ALLOWABLE DISCHARGEIn relation to this chapter, the minimum rate that can be discharged for any drainage area for design storm events up to and including the ten-year event, regardless of the modeled predevelopment runoff estimate.
NRCSUSDA Natural Resources Conservation Services (SCS).
OUTFALLPoint where water flows from a conduit, stream, or drain.
OUTLETPoints of water disposal from a stream, river, lake, tidewater or artificial drain.
PA DEPPennsylvania State Department of Environmental Protection.
PA DOTPennsylvania State Department of Transportation.
PEAK DISCHARGEThe maximum rate of stormwater runoff from a specific storm event.
PERCOLATION RATEThe rate at which water moves through a soil profile. Percolation rates are measured in units of time/length.
PIPEA culvert, closed conduit, or similar structure (including appurtenances) that conveys stormwater.
POINT DISCHARGEThe discharge from a pipe or channel that concentrates runoff at a single area.
PROJECT SITEThe specific area of land where any regulated activities in the Township are planned, conducted, or maintained.
QUALIFIED PROFESSIONALAn individual registered in and licensed by the State of Pennsylvania qualified to perform stormwater analysis and design.
RECHARGE VOLUMEThe volume of water that is required to be recharged from developed sites.
REGULATED ACTIVITIESActions or proposed actions that have an impact on stormwater runoff and that are specified in §
13-1.4 of this chapter.
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 RUNOFFThe volume of runoff that is captured and not released directly into the surface waters of this commonwealth during or after a storm event.
RETURN PERIODThe 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 has a 4% probability of occurring in any given year.
RIPARIAN BUFFERA permanent area of trees and shrubs located adjacent to streams, lakes, ponds, and wetlands.
RUNOFFAny part of precipitation that flows over the land surface.
SAFE PASSAGEThe routing of peak runoff events, usually the 100-year design event, safely through a structure without failure of that structure.
SCOURGenerally refers to the change in a channel configuration provoked by sediment imbalance, due to natural or man-made causes, between the supply and transport capacity of the channel.
SEDIMENTSoils or other materials transported by surface water as a product of erosion.
SEDIMENT BASINA barrier, dam, retention or detention basin located and designed to retain rock, sand, gravel, silt, or other material transported by water.
SENSITIVE (WATER QUALITY) AREAAn area protected because development within that area could potentially cause contamination of groundwater reservoirs. These sensitive land areas are defined in Appendix B, Exhibit 1.
SHEET FLOWRunoff that flows over the ground surface as a thin, even layer, not concentrated in a channel.
SINKHOLEA localized, gradual or rapid sinking of the land surface to a variable depth, occurring in areas of carbonate bedrock; generally characterized by a roughly circular outline, a distant breaking of the ground surface and downward movement of soil into bedrock voids.
SPILLWAYA 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.
STABILIZATIONThe proper placing, grading and/or covering of soil, rock or earth to ensure their resistance to erosion, sliding or other movement.
STATE WATER QUALITY REQUIREMENTSThe regulatory requirements to protect, maintain, reclaim, and restore water quality under Title
25 of the Pennsylvania Code and the Clean Streams Law.
A system of pipes and/or open channels that convey intercepted runoff and stormwater from other sources, but excludes domestic sewage and industrial wastes.
STORMWATERDrainage runoff from the surface of the land resulting from precipitation or snow or ice melt.
STORMWATER MANAGEMENT FACILITYAny 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 PLANThe plan for managing stormwater runoff in the Spring Creek Watershed adopted by the Centre County Commissioners as required by the Act of October 4, 1978, P.L. 864 (Act 167), and known as the "Spring Creek Watershed Act 167 Stormwater Management Plan."
STORMWATER MANAGEMENT SITE PLANThe plan prepared by the developer or his 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. The contents of the SWM site plan are established in Article
IV of this chapter.
Tabular or sheet-like mass, distinct layers of homogenous or gradational sedimentary material (consolidated rock or unconsolidated earth) of any thickness, visually separable from other layers above and below by a discrete change in the character of the material deposited or by a sharp physical break deposition, or both.
STRATIGRAPHIC UNITA stratum or body of strata recognized as a unit in the classification of the rocks of the earth's crust with respect to any specific rock character, property, attribute or for any purpose such as description, mapping, and correlation.
STRUCTURAL FILLFor the purposes of this chapter, shall imply any soil mass that is compacted in lifts to some tested criteria (standard or modified proctor) such as those under foundations or adjacent to retaining walls; areas that, for several years after construction, respond to precipitation events similar to impervious areas.
SUBAREAThe smallest drainage unit of a watershed for which stormwater management criteria have been established in the stormwater management plan.
SUBDIVISIONAs defined in The Pennsylvania Municipalities Planning Code, Act of July 31, 1968, P.L. 805, No. 247.
SWALEA natural low-lying stretch of land or minor man-made conveyance channel, which gathers or carries surface water runoff.
SWMStormwater management.
TOPOGRAPHYThe general configuration of a land surface or any part of the earth's surface, including its relief and position of its natural and man-made features; the natural or physical surface features of a region, considered collectively as to its form.
TOWNSHIPHarris Township, Centre County, Pennsylvania.
TOWNSHIP ENGINEERA professional engineer licensed in the Commonwealth of Pennsylvania and duly appointed by the subject Township as its representative. In the event that a stormwater utility is formed, all references to the Township Engineer shall be considered to also imply the stormwater utility engineer.
UNDETAINED AREAAn area of a site that cannot be routed to a stormwater management facility because of its location; generally small areas around access drives or below stormwater management facilities.
USDAUnited States Department of Agriculture.
WATER QUALITY DEPTHDepth of precipitation required to be used in computing the water quality volume based on the percentage of imperviousness of a site.
WATER QUALITY SENSITIVE (WQS) DEVELOPMENTLand development projects that have a high potential to cause catastrophic loss to local water quality and could potentially threaten groundwater reservoirs. See §
13-3.2 for additional definition.
Upper surface of a layer of saturated material in the soil.
WATERS OF THIS COMMONWEALTHAny 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.
WATERSHEDThe entire region or area drained by a river or other body of water, whether natural or artificial, a drainage basin or sub-basin.
WETLANDThose 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, ferns, and similar areas.