Definitions.
ABACT ANTIDEGRADATION BEST AVAILABLE COMBINATION OF TECHNOLOGIESEnvironmentally sound and cost effective treatment, land disposal, pollution prevention and stormwater reuse BMPs that individually or collectively manage the difference in the net change in stormwater volume, rate, and quality for storm events up to and including the two-year/twenty-four-hour storm when compared to the stormwater rate, volume and quality prior to the earth disturbance activities to maintain and protect the existing quality of the receiving surface waters of this commonwealth.
ABUTTINGParcels shall be considered to be abutting when they touch or their lot lines are directly across from easements, utilities, parks, watercourses, water bodies, natural features, or private rights-of-way.
ACCELERATED EROSIONThe 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.
ACREA acre contains 43,560 square feet.
ADVERSE IMPACTA condition that creates, imposes, aggravates, or leads to inadequate, impractical, unsafe, or unhealthy conditions on a site proposed for development or on off-tract property or facilities.
ADVERSE POSSESSIONThe right of an occupant to acquire title to a property after having continuously and openly used and maintained such property over a period of 21 years without protest from the owner(s) of record.
AESTHETICThe perception of artistic elements or elements in the natural or created environment that are pleasing to the eye.
AGRICULTURAL ACTIVITYActivities 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 livestock and installation of conservation measures. Construction of new buildings or impervious area is not considered an agricultural activity.
AGRICULTURAL OPERATIONSThe production, keeping, or maintenance for sale, lease, or personal use of plants and animals useful to man. These activities shall include, but are not limited to, forages and sod crops; grains and seed crops; dairy animals and dairy products; poultry animals and poultry products; livestock, including beef cattle, sheep, swine, horses, ponies, mules, goats, or any mutations or hybrids thereof, including the breeding and grazing of any and all such animals; bees and apiary products; fur animals; trees and forest products; fruits of all kinds, including nuts and berries; vegetables; nursery, floral, ornamental and greenhouse products; or lands devoted to a soil conservation or forestry management program; and establishments primarily engaged in supplying soil preparation services, crop services, horticultural services, veterinary and other animal services, and farm labor and management services. It does not include landscaping services.
AISLEThe traveled way by which cars enter and depart parking spaces.
ALKALINITYA measure of the capacity of water to neutralize acids because of the presence of one or more of the following bases in the water: carbonates, bicarbonates, hydroxides, borates, silicates, or phosphates,
ALLEYA minor public or private thoroughfare other than a side street, which affords only a secondary means of access to abutting property and not for general traffic circulation.
APPEALA means for obtaining review of a decision, determination, order, or failure to act pursuant to the terms of this chapter.
APPLICANTAn individual, including his or her heirs, successors and assigns, making application according to the regulations contained in this chapter, and whose signature appears on any application. The "applicant" must be the property owner or authorized agent.
APPLICATION(1) (verb) The submitting of an application for permit or service in a complete state.
(noun) The document which an applicant completes, along with all supporting documents, exhibits, and plans required for development review purposes or for approval to engage in any regulated activity at a project site.
APPROVING AUTHORITY/BODYThe agency, board, group, or other legally designated individual or agency that has been charged with the review and approval of applications.
ATTENUATIONReduction in magnitude, as in the lowering of peak runoff discharge rates, in the case of dry ponds; or the reduction of contaminant concentrations, as in the action of biodegradation in wetlands or bioretention facilities.
AUTHORITYA political or corporate body created pursuant to the former act of May 2, 1945 (P.L. 382, No. 164), known as the "Municipality Authorities Act of 1945."
BASE FLOWNormally refers to the stream levels associated primarily with groundwater or subsurface contributions, as opposed to storm flow which corresponds to stream levels associated with recent precipitation and surface runoff.
BEDROCKLayer of consolidated rock over which lies an overburden of soil (regolith), including unconsolidated rock.
BENTHICPertaining to occurrence on or in the bottom sediment of wetland and aquatic ecosystems, including wetlands.
BERMA mound of earth, or the act of creating such a mound.
BEST MANAGEMENT PRACTICE (BMP)(1) 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 or 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/or 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.
Management activities, facilities, measures, or procedures used to minimize pollution to the waters of the commonwealth.
Activities, facilities, measures, or procedures used to manage the volume, rate and water quality of stormwater runoff.
BIOCHEMICAL OXYGEN DEMAND (BOD)A measure of the concentration of aerobically degradable compounds in water. It is measured as the oxygen consumed during degradation of organic and inorganic materials in water.
BIODIVERSITYThe number of species of plants and animals in a defined area. Biodiversity is measured by a variety of indices that consider the number of species and, in some cases, the distribution of individuals among species.
BIOMASSThe total mass of living tissues (plant and animal).
BIORETENTIONA method of treating stormwater by pooling water on the surface and allowing filtering and settling of suspended solids and sediment at the mulch layer, prior to entering the plant/soil/microbe complex media for infiltration and pollutant removal.
BIOSWALEA swale which promotes infiltration and pollutant reduction by use of amended soils allowing filtering and settling of suspended solids and sediment through the mulch and amended soil layer.
BMP FINGERPRININGA series of techniques for locating BMPs (particularly ponds) within a development site so as to minimize their impacts to wetlands, forest, and sensitive stream reaches.
BMP MANUALPennsylvania Department of Environmental Protection Stormwater Best Management Practices Manual, as amended or revised.
BOARDAny body granted jurisdiction under a land use ordinance or under this chapter to render final adjudications. In this chapter, this term usually, but not always, refers to the Zoning Hearing Board.
BUFFERA vegetated strip immediately adjacent to a water body. The primary function of buffers is to protect the receiving water from sediment and pollutants derived from upstream areas. Ancillary benefits may include infiltration of rainfall and habitat enhancement. A buffer is a special case of a filter strip. Forested riparian buffers are one example of a best management practice related to the use of buffers.
BUFFER AREAAn open area made available to physically separate two land uses. A buffer area exists laterally; it does not in and of itself include screening, fences, landscaping, or other treatments which exist on a vertical plane to provide additional separation between uses.
BUILDING FOOTPRINTThe area of ground hidden by a building when the building is viewed from directly above.
CALIPERThe diameter of a tree trunk.
CAMPUSThe grounds and buildings of an institution, educational facility, or business park.
CARPORTA structure with at least three sides open used for storage of one or more vehicles.
CARTWAYThe portion of a street right-of-way, paved or unpaved, intended for vehicular traffic.
CENTER LINEThe projected line running exactly halfway between and parallel to the right-of-way lines of a street.
CERTIFICATE OF FLOODPLAIN COMPLIANCEA certificate issued by the Floodplain Permit Officer after it has been determined that all construction, development, use of land, or interior repair have been completed according to the requirements of this chapter. No structure shall be occupied, use undertaken, or dedication accepted by the City until after a certificate of floodplain compliance has been legally issued.
CHANNELA perceptible natural or artificial waterway which periodically or continuously contains moving water or which forms a connecting link between two bodies of water. It has a definite bed and banks which confine the water.
CHANNELIZATIONThe creation of a channel or channels resulting in faster water flow, a reduction in hydraulic residence time, and less contact between water and solid surfaces in the water body.
CHOKER COURSEA filter layer of finer material, usually crushed stone, that is installed over a coarse road base material. The purpose of the choker course is to provide a stable foundation for the construction of a pavement.
CISTERNAn underground reservoir or tank for storing rainwater.
CITYAltoona, Pennsylvania.
COMMON OPEN SPACEA parcel or parcels of land, an area of land, an area of water, or a combination of land and water within a development site designed and intended for the use or enjoyment of residents of the development, not including streets, off-street parking areas, and areas set aside for public facilities.
COMMON OWNERSHIPOwnership by one or more individuals in any form of ownership of two or more contiguous lots.
COMPLETE STATEAn application submitted with all required, relevant and pertinent information necessary for the approving body to render an informed decision.
COMPLETELY DRY SPACEA space which will remain totally dry during flooding; the structure is designed and constructed to prevent the passage of water and water vapor.
COMPREHENSIVE PLANWhen capitalized, the Comprehensive Plan for Altoona, as it may be amended from time to time. Otherwise, a plan plus any amendments or any of its component parts for the development of a county or municipality, providing the continuing orderly development of the municipality. The plan includes such elements as a statement of community development objectives, plans and policies for land use, housing, transportation, community facilities and utilities, and strategies for plan implementation.
CONCENTRATED WATER FLOW AREASThose natural or manmade ares where stormwater runoff is channeled and conveyed directly to a surface body of water. Concentrated water flow areas include but are not limited to ditches, waterways, gullies, and swales.
CONSERVATION DISTRICT(The Blair County 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
102.
A plan that identifies conservation practices and includes site specific BMPs for agricultural plowing or tilling activities and animal heavy use areas.
CONSTRUCTIONAny grading, excavating, or placing of earth fill, erection of buildings or other structures, including the grubbing and clearing of trees, brush, and other vegetation; provided, however, that any such activity in connection with farming, forestry, test boring or surveying shall not be deemed construction. Also includes the reconstruction, renovation, repair, extension, expansion, alteration, adaptive reuse, rehabilitation, restoration or relocation of a building or structure, including the placement of a manufactured home.
CONSTRUCTION PLANThe maps, plans, plats, or drawings accompanying a development plan and showing the specific location and design of improvements to be installed in the project in accordance with the requirements of this chapter.
COUNTYBlair County, Pennsylvania.
COVERAGESee "building, coverage" and "lot, coverage."
CRITICAL DEPTHThe depth of flow at which the specific energy is a minimum for a given discharge rate. Flow is critical when the Froude number is equal to one:
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where V, is the velocity of the flow, g, is the gravitational constant, and D, is the hydraulic depth of the flow. |
A pipe, conduit, or similar structure for the free passage of surface drainage through or under a highway, railroad, canal, or other embankment.
CUT(2) The difference between a point on the original ground and designated point of lower elevation on the final grade.
Also, the material removed in excavation.
DECISIONFinal adjudication of any board or other body granted jurisdiction under any land use ordinance or this chapter to do so, either by reason of the grant of exclusive jurisdiction or by reason of appeals from determinations.
DEDICATIONThe deliberate appropriation of land by its owner for any general and public use, reserving to himself no other rights than those that are compatible with the full exercise and enjoyment of the public uses to which the property has been devoted.
DENSE GRADED MATERIALGranular mixture characterized by a large range in particle sizes. Dense graded materials have superior structural properties to open graded materials. However, they are less permeable.
DENSITYThe cumulative measure of the average number of items in a specific space.
DEPThe Pennsylvania Department of Environmental Protection.
DEPARTMENTAltoona City departments may be referred to in this manner when the context is appropriate,
DEPARTMENT OF TRANSPORTATIONThe Pennsylvania Department of Transportation, its bureaus, departments, districts, or divisions. May be abbreviated as PennDOT.
DESIGN CONTINUITYA unifying or connecting theme or physical feature for a particular setting or place.
DESIGN CRITERIA(1) Engineering guidelines specifying construction details and materials.
Objectives, results, or limits which must be met by a facility, structure, or process in performance of its intended functions.
DESIGN FITContinuity in a scale, quality, or character between new and existing development so as to avoid abrupt or severe differences.
DESIGN STORMThe magnitude and temporal distribution of precipitation from a storm event measured in probability of occurrence (e.g., fifty-year storm) and duration (e.g., 24 hours), and used in the design and evaluation of stormwater management control systems. Also see "return period."
DESIGN VOLUMEThe volume of runoff that is captured and released into the waters of the commonwealth at a controlled rate.
DETENTIONThe 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 BASINA basin designed to retard stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate. A detention basin is designed to drain completely after a storm event.
DETENTION FACILITIESCan be above or below ground, open or enclosed, including but not limited to pipe storage, wet ponds, basins, rain gardens, bioretention areas, etc. For further reference, refer to the City of Altoona Planning Code and the DEP BMP Manual for further examples.
DETENTION VOLUMEThe volume of runoff that is captured and released into the waters of the commonwealth at a controlled rate.
DETERMINATIONFinal action by an officer, body, or agency charged with the administration of any land use ordinance or applications thereunder, except City Council, the Zoning Hearing Board, and the Planning Commission.
DEVELOPERThe person, persons, or any corporation, partnership, association, or other entity or any responsible person therein or agent therefor that undertakes the activities associated with changes in the built or human environment. The term "developer" is intended to include but not necessarily be limited to the terms "subdivider," "owner," and "builder" even though the individuals involved in successive stages of a project may vary.
DEVELOPMENTAny man-made change to improved or unimproved real estate, including, but not limited to, the construction, reconstruction, renovation, repair, expansion, or alteration of buildings or other structures; the placement of streets and other paving; any activity affecting stormwater runoff characteristics; utilities; filling, grading and excavation; mining; dredging; drilling operations; storage of equipment or materials; and the subdivision of land.
DEVELOPMENT PLANThe provision for development including a plat, all covenants relating to use, location and bulk of buildings and other structures, intensity of use or density of development, streets, ways and parking facilities, common open space and public facilities. The phrase "provisions of the development plan," when used in this chapter, shall mean the written and graphic materials referred to in this definition.
DEVELOPMENT WHICH MAY ENDANGER HUMAN LIFEIn accordance with the Pennsylvania Floodplain Management Act and regulations adopted by the Department of Community and Economic Development pursuant to that act, any activity requiring the production, storage, use of any amount of radioactive substances; structures or land used for the production or storage of any quantity of the following materials; or structures or land used for any activity requiring the maintenance of a supply (more than 550 gallons or other comparable volume) of the following materials;
(11) Nitric acid and oxides of nitrogen.
Petroleum products (gasoline, fuel oil, etc.).
Sulfur and sulfur products.
Pesticides (including insecticide, fungicides and rodenticides).
Radioactive substances, insofar as such substances are not otherwise regulated.
DISCHARGEThe flow or rate of flow from a canal, conduit, channel or other hydraulic structure.
DISTURBED AREAAn unstabilized land area where an earth disturbance activity is occurring or has occurred.
DITCHA trench dug in the ground that is shaped in a V or U that conveys stormwater.
DIVERSION TERRACEA channel and a ridge constructed to a predetermined grade across a slope and designed to collect and divert runoff from slopes which are subject to erosion.
DRAINAGEThe removal of surface water or groundwater from land by drains, grading or other means, and includes control of runoff to minimize erosion and sedimentation during and after construction or development.
DRAINAGE AREA(1) 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."
The area served by a sewer system receiving stormwater and surface water or by a watercourse.
DRAINAGE EASEMENTA right granted by a landowner to a grantee allowing the use of private land for stormwater management purposes.
DRAINAGE FACILITYAny ditch, gutter, culvert, storm sewer or other structure designed, intended, or constructed for the purpose of carrying, diverting, or controlling surface water or groundwater.
DRIVEWAYA private vehicular passageway providing access between a street and a private parking area or private garage.
DRY SWALEThe dry swale consists of an open channel capable of temporarily storing the water quality treatment volume, and a filtering medium consisting of a soil bed with an underdrain system. The dry swale uses volume-based sizing criteria. The dry swale is designed to drain down between storm events within approximately one day. The water quality treatment mechanisms are similar to bioretention practices, except that the pollutant uptake is likely to be more limited since only a grass cover crop is available for nutrient uptake.
E&SErosion and sedimentation.
E&S PERMITA permit required for earth disturbance activities where the earth disturbance is associated with timber harvesting, road maintenance activities, or oil and gas activities.
EARTH DISTURBANCE ACTIVITYA construction or other human activity which disturbs the surface of the land, including, but not limited to: land clearing and grubbing, grading, excavations, embankments, land development, agricultural plowing or tilling, operation of animal heavy use areas, timber harvesting activities, road maintenance activities, oil and gas activities, well drilling, mineral extraction, and the moving, depositing, stockpiling, or storing of soil, rock or earth materials. Earth disturbance activity is subject to regulation under 25 Pa. Code
92, 25 Pa. Code
102, and/or the Clean Streams Law.
The grant of one or more property rights by the property owner to and/or for use by the public, a corporation, an entity, or a person or persons.
ECOSYSTEMAll organisms and the nonliving environmental factors with which they interact.
ELEVATIONAn elevation measured from a datum plane. For the purpose of this chapter, all elevations are referenced to the National Geodetic Vertical Datum of 1929 (NGVD) based on mean sea level.
ELEVATION PLAN OR VIEWA plan view of a building drawn as it would appear if the viewer were looking at the building across a horizontal plane standing at ground level.
EMERGENT PLANTA rooted, vascular plant that grows in periodically or permanently flooded areas and has parts of the plant (stems and leaves) extending through and above the water plane.
EMINENT DOMAINThe authority to acquire or take, or to authorize the taking of, private property for public use or public purpose.
ENCROACHMENTAny 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, or intrudes within established regulatory or ownership boundaries.
ENGINEERAn individual licensed and registered under the laws of the commonwealth of Pennsylvania to engage in the practice of engineering. An engineer shall not practice land surveying as defined and set forth in this chapter, unless the engineer is also a registered surveyor.
ENGINEERINGThe application of the mathematical and physical sciences for the specific design of any construction, development, use of land, or interior repair as defined herein.
ENGINEERING SPECIFICATIONSThe engineering criteria of the City of Altoona regulating the installation of any improvement or facility.
EROSIONThe natural process by which the surface of the land is worn away by water, wind, ice, glaciers, or chemical action.
EROSION AND SEDIMENTATION (E&S) CONTROL PLANA plan for a project site which identifies best management practices to minimize accelerated erosion and sedimentation resulting from the removal of the surface of the land through the combined action of man's activities and natural processes.
ESSENTIALLY DRY SPACEA space which will remain dry during flooding, except for the passage of some water vapor or minor seepage; the structure is substantially impermeable to the passage of water.
EUTROPHICWater containing an excess of plant-growth nutrients that typically result in algae blooms and extreme (high and low) dissolved-oxygen concentrations.
EVAPOTRANSPIRATIONThe combined processes of evaporation from the water or soil surface and transpiration of water by plants.
EXCAVATIONAny act by which earth, sand, gravel, rock, or any other material is dug into, cut, quarried, uncovered, removed, displaced, relocated, or bulldozed. It shall include the conditions resulting therefrom.
EXCESSIVELY RAPID DRAINAGEFor purposes of the PA BMP manual, this corresponds to infilitration rates of soils in excess of six inches per hour. (Normally six inches is considered rapid drainage but the PA BMP manual indicates that special precautions need to be taken with an infiltration rate of six inches per hour or more.)
EXFILTRATEThe leaking of water to surrounding ground through openings in structures.
EXISTING CONDITIONThe dominant land cover during the five-year period immediately preceding a proposed regulated activity.
EXOTIC SPECIESA plant or animal species that has been intentionally or accidentally introduced and that does not naturally occur in a region.
EXTENDED DETENTIONA function provided by BMPs which incorporate a water quality storage. BMPs with extended detention, intercept runoff and then release it over an extended period of time.
EXTENDED DETENTION (ED) PONDTemporarily detains part of stormwater runoff for up to 24 hours after a storm by using a fixed orifice. ED ponds normally are "dry" between storm events and do not have permanent standing water. An enhanced ED pond is designed to prevent clogging and resuspension. It provides flexibility in achieving target detention times. It may be equipped with plunge pools near the inlet, a micropool at the outlet, and may have an adjustable reverse-sloped pipe at the ED control device.
EXTENDED DETENTION CONTROL DEVICEA pipe or series of pipes that extend from the riser of the stormwater pond that are used to gradually release stormwater from the pond over a twelve- to forty-eight-hour interval.
FASCINEBundled willow cuttings used to stabilize stream banks. Bundling allows otherwise weak green twigs to reinforce each other and resist the forces of stream currents.
FEMAThe Federal Emergency Management Agency.
FIELD CAPACITYThe quantity of water which will not freely drain from the root zone of shallow soil layers. Usually measured as the moisture content (by volume) in soil at a capillary tension of .33 bars.
FILLSand, gravel, earth or other material placed or deposited so as to form an embankment or raise the elevation of the land surface. The term includes material used to replace an area with aquatic life with dry land or to change the bottom elevation of a surface water area.
FILTER STRIPA vegetated boundary characterized by uniform mild slopes. Filter strips may be provided down-gradient of developed tracts to trap sediment and sediment-borne pollutants and to reduce imperviousness. Filter strips may be forested or vegetated turf. Filter strips located adjacent to waterbodies are called buffers.
FLASH BOARDSRemovable boards used in a weir to control water levels.
FLOATING AQUATIC PLANTA rooted or non-rooted vascular plant that is adapted to have some plant organs (generally the chlorophyll-bearing leaves) floating on the surface of the water in wetlands, lakes, and rivers.
FLOODA temporary inundation of normally dry land areas.
FLOOD FRINGEThe flood fringe occupies the distal parts of the floodplain, outside of the floodway. Complete obstruction of the flood fringe will not significantly increase flood levels. The flood fringe boundary is typically based on an increase in flood level of one foot during the one-hundred-year return frequency flooding event.
FLOOD INSURANCE RATE MAP (FIRM)The official map on which the Federal Emergency Management Agency or Federal Insurance Administration has delineated both the areas of special flood hazards and the risk premium zones applicable to the community.
FLOOD INSURANCE STUDY (FIS)The official report provided by the Federal Insurance Administration that includes flood profiles, the Flood Insurance Rate Map, the Flood Boundary Map, and the water surface elevation of the base flood.
FLOODPLAIN(1) Any land susceptible to being inundated by water from any source during the base flood, as delineated on the most current floodplain maps prepared by the Federal Insurance Administration and approved by the Federal Emergency Management Agency (FEMA) for the purpose of determining the official federal designated floodplain, floodway and floodway fringe. These maps are based on the most current Flood Insurance Study prepared by the Federal Emergency Management Agency; the study being the definitive source of floodplain information, particularly in regards to base flood elevations and floodway widths as reflected in the floodplain regulations of the City of Altoona and indicated on the flood boundary and Floodway Maps. Also includes areas that comprise Group 13 soils, as listed in Appendix A of the DEP Technical Manual for Sewage Enforcement Officers, as amended.
Lands adjoining a river or stream that have been or may be expected to be inundated by flood waters in a one-hundred-year frequency flood.
FLOODWAYThe channel of a water course and those portions of the adjoining floodplains that are reasonably required to carry and discharge the one-hundred-year flood or base flood without cumulatively increasing the water surface elevation more than one foot. Unless otherwise specified, the boundary of the floodway is indicated on maps and flood insurance studies provided by FEMA. In any case 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.
FOREBAYStormwater design feature that uses a small basin to settle out incoming sediment before it is delivered to a stormwater BMP.
FOREST MANAGEMENT/TIMBER OPERATIONSAll activities connected with management of forestland. These include inventory, preparation, growing and harvesting of forest products including the site preparation, cultivation and logging of trees, and the construction and maintenance of roads.
FORESTRY ACTIVITIESThe management of forests and timberlands when practiced in accordance with accepted silvicultural principles, through developing, cultivating, harvesting, transporting and selling trees for commercial purposes, which does not involve any land developments.
FREEBOARDThe vertical distance between water surface elevation experienced during the design flood and the crest elevation of a dam, levee, floodwall or other embankment.
FRESH WATERWater with a total dissolved solids content less than 500 mg/L (0.5 parts per thousand salts).
FRONTAGEThe linear distance which a property line runs coincident with a street right-of-way line. Frontage may be measured from any abutting street, but all required frontage must be measured from the same street. The street from which frontage is gained need not be the street to which the structure(s) on the lot are faced. Frontage cannot be gained from alleys, driveways, or elevated or buried roadways.
FRONTAGE ROADMinor collector streets parallel and adjacent to arterial streets, providing access to abutting properties and control of intersections with an arterial street.
GABIONWire cage used to contain rip rap and stone. Gabions are used to increase the resistance of rip rap to movement caused by flowing water.
GENERAL PUBLICAny and all individuals, without any prior qualifications.
GEOTEXTILEA fabric manufactured from synthetic fiber that is designed to achieve specific engineering objectives, including seepage control, media separation (e.g., between sand and soil), filtration, or the protection of other construction elements such as geomembranes.
GOVERNMENTAL AGENCYAny department, commission, independent agency, or instrumentality of the United States, the commonwealth of Pennsylvania, a Pennsylvania county, the City of Altoona, a Pennsylvania municipality or authority. The administrative offices of a public school district are included, but no other school district use or building qualifies.
GRADEThe slope of ground, street, or other public way, specified in percentage of change in elevation per horizontal distance; the act of altering the topography of undisturbed land.
GRADE, FINISHEDThe completed surfaces of lawns, walks, and roads brought to grades as shown on official plans or designs relating thereto.
GRASSED WATERWAYA natural or man-made low-lying stretch of land which gathers or carries surface water runoff, also known as a "swale."
GREEN INFRASTRUCTURESystems and practices that use or mimic natural processes to infiltrate, evapotranspire, or reuse stormwater on the site where it is generated.
GREENWAYA strip or belt of vegetated land that typically includes both upland and riparian areas. Greenways are often used for recreation, as a land use buffer, or to provide a corridor and habitat for wildlife.
GROUNDWATERSubsurface water occupying the saturation zone from which wells and springs are fed.
GROUNDWATER RECHARGEReplenishment of existing natural underground water supplies or groundwater naturally by precipitation or runoff.
HABITATThe environment occupied by individuals of a particular species, population, or community.
HEADWALLA wall of stone, metal, concrete, or wood at the end of a culvert or drain to protect fill from scour or undermining, increase hydraulic efficiency of conduit, divert flow, retard disjointing of short sectional pipe, or serve as a retaining wall.
HEARINGAn administrative proceeding conducted by a board.
HEAVY METALSMetallic elements having atomic weights above 21 on the periodic table.
HERBACEOUSPlant parts that contain chlorophyll and are nonwoody.
HYDRAULIC CONDUCTIVITY (K)An expression of the readiness with which a liquid such as water flows through a soil in response to a given potential gradient. Hydraulic conductivity is a constant physical property of soil or rock, one of several components responsible for the dynamic phenomenon of flow.
HYDRAULIC LOADING RATE (HLR)Ratio of the surface area of a hydraulic device and the average rate at which water is delivered to the area. Measure of the application of a volume of water to a land area with units of volume per area per time or simply reduced to applied device water depth per time (for example, m3/(m2/d) or cm/d).
HYDRAULIC RESIDENCE TIME (HRT)A measure of the average time that water occupies a given volume with units of time. The theoretical HRT is calculated as the volume divided by the flow (for example, m3/(m2/d)). The actual HRT is estimated on the basis of tracer studies that used conservative tracers such as lithium or dyes.
HYDRIC SOILA soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions. Hydric soil that is in areas having indicators of hydrophytic vegetation and wetland hydrology is wetland soil.
HYDROGRAPHA record of the change in flow rate with time.
HYDROLOGIC SOIL GROUP (HSG)(1) 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.
A designation developed by the NRCS which describes the infiltration capacity of soil. Soil associations are categorized in decreasing infiltration capacity from A to D.
HYDROPERIODThe period of wetland soil saturation or flooding. Hydroperiod is often expressed as a number of days or a percentage of time flooded during an annual period (for example, 25 days or 7%).
IMPACT FEEA fee imposed on a development to finance the cost of improvements to services and infrastructure necessary to accommodate the development and its effects.
IMPERVIOUSNot allowing or allowing only with great difficulty the movement of water; impermeable.
IMPERVIOUS SURFACE (IMPERVIOUS AREA)A surface that prevents the infiltration or percolation 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 street, sidewalk, deck, parking lots, as well as driveway areas.
IMPROVEMENTSAny physical addition or installation or construction required by the City to render land suitable for the use intended and including, but not limited to, streets, curbs and gutters, sidewalks, street signs and lights, walkways, sewer and water facilities, monuments and markers, grading, and stormwater drainage facilities.
INFILTRATION(1) The flow or movement of water through the interstices or pores of a soil or other porous medium.
The entrance or absorption of surface water into the soil, usually at the soil/air interface.
INFILTRATION STRUCTURESA structure designed to direct runoff into the ground (e.g., french drains, seepage pits, seepage trenches).
INFILTRATION TESTINGSpecific tests designed to measure the saturated movement of water into the soil in a single direction downward through a two dimensional soil surface.
INLETThere are four major types of stormwater inlets:
(2) CURB INLETHas an opening in the curb. Also referred to as an open mouth inlet.
INLET TRAPAn inlet trap is used on a combined sewer/storm sewer system. A ninety-degree bend turned down on the outlet pipe in an inlet. Water builds up in the inlet sump covering the bottom of the elbow thus preventing sewer gas from entering the inlet.
INTERMITTENT STREAMA body of water flowing in a channel or bed composed primarily of substrates associated with flowing water, which, during periods of the year, is below the local water table and obtains its flow from both surface runoff and groundwater discharges.
KARSTA type of topography or landscape characterized by surface depressions, sinkholes, rock pinnacles/uneven bedrock surface, underground drainage, and caves. Karst is formed on carbonite rocks, such as limestone or dolomite.
KNOWINGLYAs used in this chapter, means having knowledge of, or reason to know, or a belief or ground for belief which warrants further inspection or inquiry of: the character and content of any material or performance described herein which is reasonably susceptible of examination by a licensee or person; the age of the minor; provided, however, that an honest mistake shall constitute an excuse from liability hereunder if the licensee or person made a reasonable bona fide attempt to ascertain the true age of such minor. "Knowingly" also means that a reasonable person using reasonable skills and faculties would have known or been aware.
LANDGround, soil, or earth, including structures on, above, or below the surface.
LAND DEVELOPMENT (DEVELOPMENT)Inclusive of any or all of the following meanings: The improvement of one lot or two or more contiguous lots, tracts, or parcels of land for any purpose involving any activity enumerated in §
640-44 or as otherwise defined in the Municipalities Planning Code (Section 503(1.1).
Any activity involving the changing, grading, transportation, fill and any other activity which causes land to be exposed to the danger of erosion.
LAND SURVEYINGThe location, relocation, establishment, reestablishment or retracement of any property line or boundary of any parcel of land or any lot right-of-way, easement, or alignment. This process shall include the principles of land surveying; determination of the position of any monument or reference point that marks a property line, boundary, or corner; setting, resetting, or replacing any such monument or individual point, including the writing of deed descriptions. This process shall also include the determination of elevations and topographic surveys. Land surveying shall be practiced by a surveyor or engineer registered under the laws of the commonwealth of Pennsylvania to engage in the practice of land surveying.
LANDLOCKEDAny lot or parcel without any access to the public roadway system.
LANDOWNERThe 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 he or she is authorized under the lease to exercise the rights of the landowner, or other person having a proprietary interest in land.
LANDSCAPE(1) An expanse of natural scenery.
Lawns, trees, plants, rocks, wood chips, and decorative features such as sculptures, patterned walks, fountains, and pools.
LICENSED PROFESSIONALProfessional engineers, landscape architects, geologists and land surveyors licensed to practice in this commonwealth.
LIMNETICRelating to or inhabiting the open water part of a freshwater body with a depth that light penetrates. The area of a wetland without emergent vegetation.
LITTORAL ZONEThe shoreward zone of a lake or wetland. The area where water is shallow enough for emergent vegetation to dominate.
LONG TERM OPERATION AND MAINTENANCEThe routine inspection, maintenance, repair or replacement of a BMP to ensure proper function for the duration of time that the BMP is needed.
LOW IMPACT DEVELOPMENTSight design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration, evapotranspiration, and the 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.
MAINTENANCEThe upkeep necessary for efficient operation of physical properties or BMPs.
MANNING'S EQUATIONA formula for calculating the anticipated uniform flow in an open-channel flow, published by Manning in 1890.
MARSHA wetland dominated by herbaceous emergent plants.
MEDIATIONA voluntary negotiating process in which parties in a dispute mutually select a neutral mediator to assist them in jointly exploring and settling their differences, culminating in a written agreement which the parties themselves create and consider acceptable.
MITIGATION(1) Methods used to alleviate or lessen the impact of development.
The replacement of functional values lost when an ecosystem is altered. Mitigation can include replacement, restoration, and enhancement of functional values.
MODIFICATIONSNo modification or changes, during or after construction, to the approved Stormwater Management Plan are permitted without written permission from the City of Altoona. If permission is granted, an as-built or record drawing must be submitted to the City of Altoona Stormwater Officer.
MONUMENTStone or concrete monument of known coordinates, established by professional land surveyors, and utilized to locate property lines.
MUNICIPAL AUTHORITYA body politic and corporate created pursuant to the Act of May 2, 1945 (P.L. 382, No. 164), formerly known as the Municipality Authorities Act of 1945.
MUNICIPAL ENGINEERA professional engineer licensed in the commonwealth of Pennsylvania, duly appointed by the City of Altoona.
NATURAL STORMWATER RUNOFF REGIMEA watershed where natural surface configurations, runoff characteristics and defined drainage conveyances have attained the conditions of equilibrium.
NEW CONSTRUCTIONStructures, including any improvements or alterations, for which the necessary permits to start construction were applied for on or after July 24, 2003.
NITRIFICATIONBiological transformation (oxidation) of ammonia nitrogen to nitrite and nitrate forms.
NITROGEN FIXATIONA microbial process in which atmospheric nitrogen gas is incorporated into the synthesis of organic nitrogen.
NOI NOTICE OF INTENTA request, on a form provided by the Department, for coverage under a general NPDES permit for stormwater discharges associated with construction activities or an E&S permit.
NONDISCHARGE ALTERNATIVEEnvironmentally sound and cost-effective BMPs that individually or collectively eliminate the net change in stormwater volume, rate and quality for storm events up to and including the two-year twenty-four-hour storm when compared to the stormwater rate, volume and quality prior to the earth disturbance activities to maintain and protect the existing quality of the receiving surface waters of this commonwealth.
NORMAL POOL ELEVATION(1) For bodies of water which have no structural measures to regulate height of water, the height of water at ordinary stages of low water unaffected by drought.
For structurally regulated bodies of water, the elevation of the spillway, outlet control, or dam crest which maintains the body of water at a specified height.
The term does not apply to wetlands.
NOTICE OF TERMINATIONA request, on a form provided by DEP, to terminate coverage under a general or individual NPDES permit for stormwater discharges associated with construction activities or other permits under Chapter 102.
NPDESSee National Pollutant Discharge Elimination System.
NPDES PERMIT FOR STORMWATER DISCHARGES ASSOCIATED WITH CONSTRUCTION ACTIVITIESA permit required for the discharge or potential discharge of stormwater into waters of this commonwealth from construction activities, including clearing and grubbing, grading and excavation activities involving one acre (0.4 hectare) or more of earth disturbance activity or an earth disturbance activity on any portion, part, or during any stage of, a larger common plan of development or sale that involves one acre (0.4 hectare) or more of earth disturbance activity over the life of the project.
NRCSUSDA Natural Resources Conservation Service (formerly SCS).
OBSTRUCTIONAny wall, dam, wharf, embankment, levee, dike, pile abutment, projection, excavation, channel, rectification, culvert, building, fence, stockpile, refuse, fill, structure, or matter in, along, across, or projecting into any channel, watercourse, or flood-prone areas:
(1) Which may impede, retard, or change the direction of the flow of water either in itself or by catching or collecting debris carried by such water; or
Which is placed where the flow of the water might carry the same downstream to the damage of life and property.
ON-SITE STORMWATER MANAGEMENTThe 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 is not significantly different than if the site had remained undeveloped.
OPEN SPACEThat space open from the ground to the sky of which 80% must be vegetative material.
OPEN SPACE RATIOTotal area of open space divided by the total site area in which the open space is located.
OPEN-GRADED MATERIALUniform granular mixture with a narrow distribution of grain sizes. Open-graded material has higher permability than dense graded material.
OPERATORA person who has one or more of the following:
(1) Oversight responsibility of earth disturbance activity on a project site or a portion thereof who has the ability to make modifications to the E&S plan, PCSM plan or site specifications.
Day-to-day operational control over earth disturbance activity on a project site or a portion thereof to ensure compliance with the E&S plan or PCSM plan.
OUTFALL(1) The point, location or structure where drainage discharges from a sewer, drain, pipe, or other conduit.
A point of discharge from a sewer or drain to a water body.
OUTLETThe point at which water discharges from a river, creek or other flow line; lake, tidal basin or drainage depression; or pipe, channel, dam or other hydrologic structure.
OUTLET CONTROL STRUCTUREThe means of controlling the relationship between the headwater elevation and the discharge, placed at the outlet or downstream end of any structure through which water may flow.
PALUSTRINE WETLANDAll nontidal wetlands dominated by trees, shrubs, persistent emergents, emergent mosses, or lichens; and all such tidal wetlands in areas where salinity from ocean - derived salts is below 0.5 parts per thousand.
PCSMPost construction stormwater management.
PCSM PLANA site-specific plan consisting of both drawings and a narrative that identifies BMPs to manage changes in stormwater runoff volume, rate and water quality after earth disturbance activities have ended and the project site is permanently stabilized.
PEAK DISCHARGEThe maximum rate of flow of water at a given point and time resulting from a storm event.
PEAK FLOWMaximum flow resulting from a storm event.
PENNDOTThe Pennsylvania Department of Transportation.
PENNSYLVANIA AGRONOMY GUIDEThe quick reference book published by the Cooperative Extension Service as a practical guide to gain and forage production, soil fertility management, pest management, and erosion control, with special reference to Pennsylvania conditions.
PENNSYLVANIA EROSION & SEDIMENT POLLUTION CONTROL PROGRAM MANUALA primary reference document published by the Pennsylvania Department of Environmental Resources, Bureau of Land and Water conservation, which is used by technically trained persons to prepare erosion and sedimentation control plans for earth moving activities.
PERCOLATIONThe downward movement under the influence of gravity of water under hydrostatic pressure through the interstices of the rock or soil.
PERCOLATION TESTA test which evaluates the soil suitability by determining the rate at which effluent can be expected to seep into the soil.
PERENNIALPersisting for more than one year. Perennial plant species persist as woody vegetation from year to year or resprout from their rootstock annually.
PERENNIAL STREAMA body of water flowing in a channel or bed composed primarily of substrates associated with flowing waters and capable, in the absence of pollution or other manmade stream disturbances, of supporting a benthic macro-invertebrate community which is composed of two or more recognizable taxonomic groups of organisms which are large enough to be seen by the unaided eye and can be retained by a United States Standard No. 30 sieve (28 meshes per inch, 0.595 mm openings) and live at least part of their life cycles within or upon available substrates in a body of water or water transport system.
PERFORMANCE STANDARDA standard which establishes an end result or outcome which is to be achieved but does not prescribe specific means for achieving it.
PERIMETER BMPsBMPs placed or constructed along the perimeter of an earth disturbance area to prevent runoff from entering the disturbed area, or to capture and treat sediment runoff prior to leaving a disturbed area.
PERMEABILITYThe ability of rock, soil or other material to transmit a gas or liquid.
PERMITWritten governmental permission issued by an authorized official, empowering the holder thereof to do some act not forbidden by law but not allowed without such an authorization.
PERMITTEE and/or LICENSEEA person in whose name a permit and/or license has been issued. This person is also the individual listed as an applicant on the application for a permit and/or license.
PERMITTIVITY (CROSS-PLANE FLOW CAPACITY)Rate that water will flow freely through a thin layer, such as a geotextile. Equal to the hydraulic conductivity divided by the thickness of the layer. Permittivity is measured in units of inverse time.
PERSONAn individual, partnership, sole proprietorship, public or private association or corporation, firm, trust, company, corporation, estate, municipality, government unit, public utility or any other legal entity whatsoever which is recognized by law as the subject of rights and duties.
PHOTIC ZONEThe area of a water body receiving sunlight.
PLAN, FINALA complete and exact development plan prepared for official recording as required by statute; a final plat.
PLAN, SKETCHAn informal optional submission preparatory to the preliminary plan, showing the general intent of the applicant.
PLANNED RESIDENTIAL DEVELOPMENT (PRD)An area of land controlled by a landowner to be developed as a single entity for a number of dwelling units or combination of residential and nonresidential uses, the development plan for which does not correspond in lot size, bulk, type of dwelling, or use, density, or intensity, lot coverage and required open space to the regulations established in any one district created, from time to time, under the provisions of this chapter.
PLUG FLOWLinear flow along the length of a wetland cell. Ideal plug flow does not involve the dispersion or diffusion of constituents. The flow can be perceived as a series of independent packets of water that do not interact with each other.
PLUNGE POOLA small permanent pool at either the inlet to a BMP or at the outfall from a BMP. The primary purpose of the pool is to dissipate the velocity of stormwater runoff.
POINT SOURCEAny 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 and further defined in State regulations at 25 Pa. Code § 92a2.
POLLUTANTAny contaminant or other alteration of the physical, chemical, biological or radiological integrity of surface water which causes or has the potential to cause pollution as defined in Section 1 of the Clean Streams Law (35 P.S. §
691.1).
Removing pollutants by decomposing them or eliminating them from an area or system (e.g., volitize), or rendering nonharmful or unavailable in a soil or medium by means of adsorption, chelation, and similar binding mechanisms.
PORE SPACEOpen space in rock or granular material; also known as interstices.
PPC PLAN—PREPAREDNESS, PREVENTION AND CONTINGENCY PLANA written plan that identifies an emergency response program, material and waste inventory, spill and leak prevention and response, inspection program, housekeeping program, security and external factors, and that is developed and implemented at the construction site to control potential discharges of pollutants other than sediment into waters of this commonwealth.
PRECIPITATIONA deposit on the earth of hail, mist, sleet, rain or snow.
PREMISESAny lot, parcel or tract of land and any building constructed thereon.
PRINCIPAL USEThe primary or predominant uses of any lot or parcel.
PRIVATE ROADA legally established right-of-way, other than a street, which provides the primary vehicular access to a lot or lots, and is privately maintained.
PROBABLE MAXIMUM FLOOD (PMF)The flood that may be expected from the most severe combination of critical meteorological and hydrologic conditions that are reasonably possible in an area. The PMF is derived from the probably maximum precipitation (PMP) as determined on the basis of data obtained from the National Oceanographic and Atmospheric Administration (NOAA).
PROJECT SITEThe specific area of land where any regulated activities in the City are planned, conducted, or maintained.
PROPERTYA lot, parcel, or tract of land, as well as the building and structures located thereon.
PUBLIC HEARINGA formal meeting held pursuant to public notice by the appropriate agency, intended to inform and obtain public comment, prior to taking action on a matter before the agency.
PUBLIC MEETINGA forum held pursuant to notice under the act of July 3, 1986 (P.L. 388. No. 84), known as the "Sunshine Act."
PUBLIC NOTICENotice published pursuant to controlling legislation intended to inform the general public of an activity, usually a hearing or series of meetings.
QUALIFIED PROFESSIONALAny person licensed in Pennsylvania or otherwise qualified by law to perform the work required by this chapter.
QUIT CLAIMA legal document conveying interest, not property, between parties.
QUORUMA majority of the full authorized membership of a board or agency.
RAINGARDENAlso called bioretention, a raingarden is an excavated shallow surface depression planted with specially selected native vegetation to treat and capture runoff. Also see bioretention.
RATE OF FLOWThe quantity of water that flows in a certain time under specified conditions.
REASONABLE USE DOCTRINEA common law principle that no one has the right to use his or her property in a way that deprives others of the lawful enjoyment of their property.
RECEIVING WATERA water body into which wastewater or treated effluent is discharged.
RECHARGEReplenishment of groundwater reservoirs by infiltration through permeable soils.
RECORD DRAWINGSSet of prints of the original facilities showing those changes made during the construction process.
REGULATED ACTIVITYAny earth disturbance activities or any activity that may affect stormwater runoff. Also any activities that contribute stormwater or nonstormwater discharges to a regulated small MS-4.
RELEASE RATE PERCENTAGEThe 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 point of interest.
REPORTAny letter, review, memorandum, compilation, or similar writing made by any body, board, officer, or consultant other than a solicitor to any other body, board, officer, or consultant for the purpose of assisting the recipient of such report in the rendering of any decision or determination. All reports shall be deemed recommendatory and advisory only and shall not be binding upon the recipient, board, officer, body, or agency, nor shall any appeal lie therefrom. Any report used, received or considered by the body, board, officer, or agency rendering a determination or decision shall be made available for inspection to the applicant and all other parties to any proceeding upon request, and copies thereof shall be provided at cost of reproduction.
RESERVE STRIPA parcel of ground separating a street from other adjacent properties or from another street, which shall prevent a street from being connected or extended across property lines.
RETENTION PONDA 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 ponds remain wet once the runoff has been discharged.
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 PERIOD(1) 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 an average once every 25 years; or stated another way, the probability of twenty-five-year storm occurring in any one year is 0.04 or a 4% chance.
The average period of time between the occurrence of storms of equal or greater magnitude. The probability that such a storm will occur in any given year is equal to the reciprocal of the return period (e.g. there is a 50% chance that a two-year storm event will occur in any given year, but only a 10% chance that a ten-year storm event will occur).
RIGHT-OF-WAY(1) A strip of land that is acquired by reservation, dedication, forced dedication, prescription, or condemnation, and is intended to be occupied by a road, crosswalk, railroad, electric transmission line, oil pipeline, gas pipeline, waterline, sanitary sewer line, storm sewer line, and/or other similar use;
Generally, the right of one to pass over the property of another.
RIPARIANPertaining to a stream or river. Also, plant communities occurring in association with any spring, lake, river, stream, or creek through which waters flow at least periodically.
RIPARIAN BUFFERA permanent area of trees and shrubs located adjacent to streams, lakes, ponds, and wetlands.
RIPARIAN CORRIDORNarrow strip of land, centered on a stream, that includes the floodplain as well as related riparian habitats adjacent to the floodplain.
RIPARIAN FOREST BUFFERA type of riparian buffer that consists of permanent vegetation that is predominantly native trees, shrubs and forbs along surface waters that is maintained in a natural state or sustainably managed to protect and enhance water quality, stabilize stream channels and banks, and separate land use activities from surface waters.
RUNOFFThe surface water discharge after a fall of rain or snow that does not enter the soil but runs off or flows over the surface of the land.
RUNOFF CAPTURE DESIGN STORMBenchmark rainfall event, used to develop criteria for designing the groundwater recharge function of BMPs. The runoff capture design storm is the largest rainfall event from which no appreciable runoff is expected to occur. Complete specification of the storm includes the rainfall depth in inches, return frequency and storm duration. The distribution of rainfall in Pennsylvania is a Type II rainfall distribution. See Section
5.3 of the PA BMP Handbook.
The combined storage volume provided by BMPs on a site for the retention and eventual infiltration of rainfall.
RUNOFF CAPTURE VOLUMEThe minimum volume of rainfall that should be retained and completely infiltrated onsite during every storm. It is also equal to the rainfall quantity associated with the runoff capture design storm. The runoff capture volume is conveniently stated as a rainfall volume, in inches, over the area of the site.
RUNOFF CHARACTERISTICSThe 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.
RUNOFF CURVE NUMBER (CN)A parameter developed by the NRCS which is an indicator of runoff potential. Curve number is related to hydrologic soil group and land use type. The larger the runoff curve number, the greater the percentage of rainfall that will appear as runoff.
RUNOFF PEAK ATTENUATION DESIGN STORMBenchmark rainfall event, used to develop criteria for the design of runoff peak attenuation BMPs. The design criteria generally requires that the predicted post development peak runoff rate for the selected runoff peak attenuation design storm will not exceed the peak associated with redeveloped condition. Complete specification of the storm includes rainfall depth in inches, return frequency and storm duration. The distribution of rainfall in Pennsylvania is a Type II rainfall distribution. See Section
5.3 of the Handbook.
A sanitary sewage collection system, either publicly or privately owned, in which sewage is carried from individual lots by a system of pipes to a temporary central treatment and disposal plant, generally serving a neighborhood area.
SANITARY SEWAGE DISPOSAL, PUBLICA sanitary sewage collection system in which sewage is carried from individual lots by a system of pipes to a central treatment and disposal plant.
SATURATED SOILSoil in which the pore space is completely filled with water.
SCREENINGA vegetative material, landscaping, or opaque fencing of sufficient height and density to filter adequately from the adjacent properties light, noise, odors, and the views of the structures and uses on the premises upon which the landscaping, vegetative material, or fence is located.
SEASONALLY HIGH WATER TABLEShallow water tables associated with periods of recent high levels of precipitation and/or low levels of evapotranspiration. Frequently determined in the spring.
SEDIMENTSoils or other solid materials, both mineral and organic, that is in suspension and transported or moved from its site of origin by 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.
SEDIMENTATIONThe process by which mineral or organic matter is accumulated or deposited by moving water, wind or gravity.
SEEPAGE PIT/SEEPAGE TRENCHAn area of excavated earth filled with loose stone or similar material and into which surface water is directed for infiltration into the ground.
SEMI-PERVIOUS SURFACEA surface such as stone, rock, concrete or other materials which permits some vertical transmission of water.
SEPTIC TANKA watertight receptacle which receives sewage or industrial wastes and is designed and constructed to provide for sludge storage, sludge decomposition, separating solids from liquids through a period of detention before allowing the liquid to be discharged.
SETBACKA distance from the edge of a water body within which intensive development is restricted. Setbacks are established by local regulation for the purpose of maintaining open space next to streams, lakes, and other water bodies. The area within setbacks is frequently used for flood control, recreation, preservation of drinking water supply, and wildlife habitat enhancement.
SETBACK LINEThe line within a property defining the required minimum or maximum distance between any building to be erected and the adjacent property line.
SHADE TREEA tree in a public place, street, special easement, or right-of-way adjoining a street, as provided in these regulations.
SHEET FLOWWater flow with a relatively thin and uniform depth.
SHORT CIRCUITA faster, channelized water flow route that results in a lower actual hydraulic residence time than the theoretical hydraulic residence time. This may reduce the effectiveness of a BMP.
SIGHT DISTANCEThe required length of roadway visible to the driver of a passenger vehicle at any given point on the roadway when the view is unobstructed by traffic. Sight distance measurements shall be made from a point 10 feet from the edge of a cartway 3 1/2 feet high, to a point 3 1/2 feet above the road surface.
SLOPEThe rise or fall of the land usually measured in percent slope. The percent slope is equal to the rise or fall in feet for a horizontal distance of 100 feet.
SOIL CONSERVATION SERVICE (SCS)The United States Department of Agriculture Soil Conservation Service; now known as the Natural Resources Conservation Service (NRCS).
SOIL PERCOLATION TESTA field test conducted to determine the suitability of the soil for on-site sanitary sewage disposal facilities by measuring the absorptive capacity of the soil at a given location and depth.
SOIL-COVER-COMPLEX METHODA method of runoff computation developed by the Soil Conservation Service, found in Technical Release No. 55, that is based on relating soil type and land use/cover to a runoff parameter called a curve number (CN).
SPILLWAY DESIGN FLOOD (SDF)Benchmark rainfall event, used to develop criteria for the design of BMPs that incorporate emergency spillways or overflows. Complete specification of the storm includes rainfall depth in inches, return frequency and storm duration. The distribution of rainfall in Pennsylvania is a Type II rainfall distribution. See Section
5.3 of the Handbook.
Natural or mechanical treatment of a mass of soil or ground area to increase or maintain its stability and ensure its resistance to erosion, sliding, or other movement.
STAGE DISCHARGE CURVEA line graph showing the relationship between water depth and outflow from a body of water.
STAGE-AREA CURVEA line graph showing the relationship between the depth of water and the surface area of a pond, wetland, or lake.
STATE WATER QUALITY REQUIREMENTSThe regulatory requirements to protect, maintain, reclaim, and restore water quality under Title
25 of the Pennsylvania Code Chapters 93 and 96 and the Clean Streams Law.
A permanent structure designed to provide space for the storage of materials. Such storage space is usually provided on a rental basis by the owner to the general public. This definition does not include storage incidental to other uses on a property.
STORM FREQUENCYThe average interval in years over which a storm event of a given precipitation volume can be expected to occur.
STORM SEWERA sewer, system of pipes or conduits, which carries intercepted surface runoff, street water and other drainage but excludes domestic sewage and industrial waste.
STORMWATERDrainage runoff from the surface of the land resulting from precipitation or snow or ice melt.
STORMWATER (MANAGEMENT) FACILITYAny facility or structure, natural or man-made that due to its condition, design, or construction conveys, stores, or otherwise affects stormwater runoff. Typical stormwater management facilities whether existing or proposed, open or closed, that retains, detains, holds, carries or transmits stormwater include, but are not limited to: detention and retention basins; open channels; storm sewers; pipes; and infiltration facilities.
STORMWATER COLLECTION SYSTEMNatural 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 DRAINAGE SYSTEMA 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 MANAGEMENT PLANThe plan for managing stormwater runoff adopted by the City of Altoona and Blair County as required by the Stormwater Management Act 167.
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.
STORMWATER OFFICERDesignated employees of the City of Altoona who deal with stormwater or stormwater related issues and/or performs the duties of a Stormwater Officer as defined in this chapter.
STRUCTUREAny man-made object having an ascertainable stationary location on or in land or water, whether or not directly affixed to the land.
SUBCRITICAL FLOWThe state of flow when the depth is greater than the critical depth.
SUBDIVISIONThe 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 dwelling, shall be exempted. As defined in the Pennsylvania Municipalities Planning Code, Act of July 31, 1968, P.L. 805, No. 247.
SUBSTANTIAL IMPROVEMENT(1) Any reconstruction, rehabilitation, addition, or other improvement of an existing structure, the cost of which equals or exceeds 50% of the market value of the structure before the start of construction of the improvement. This term includes structures which have incurred substantial damage, regardless of the actual repair work performed. The term does not, however, include either:
(a) Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions; or
Any alteration of a historic structure, provided that the alteration will not preclude the structure's continued designation as a historic structure.
Where sexually oriented businesses are concerned, the term "substantial improvement" shall hold the same meaning as the term "substantial enlargement" above.
SUBSTANTIALLY COMPLETEDThe condition where a project has been constructed to the point where:
(1) All basic features have been completed.
All features necessary for public health, safety and welfare have been installed and are functioning properly.
No more than 10% of the project cost remains outstanding.
There is sufficient reason to believe the developer will complete the remaining portions of the project in a timely manner.
SUBSTRATESubstances used by organisms for growth in a liquid medium. Surface area of solids or soils used by organisms to attach.
SUCCESSIONThe temporal changes of plant and animal populations and species in an area that has been disturbed.
SUMPThe area in an inlet from the lowest outlet pipe invert to the bottom of the inlet. This area serves to catch and hold debris in the inlet. Normally varies from 18 to 30 inches.
SUPER CRITICAL FLOWThe state of flow when the depth is less than the critical depth. Transitions between supercritical and subcritical flow may result in turbulence associated with a hydraulic jump.
SURFACE DRAINAGE PLANA plan showing all present and proposed grades and facilities for stormwater drainage.
SURFACE INFILTRATION RATEThe rate at which water enters the soil or other porous surface. The measurement of surface infiltration rates requires that the underlying soil be completely saturated and that infiltration occurs by gravity under a unit hydraulic gradient.
SURFACE WATER OF THE COMMONWEALTHAny and all rivers, streams, creeks, rivulets, runs, impoundments, watercourses, lakes, ponds, springs, and all other bodies of water or channel of conveyance of surface water, or parts thereof within or on the boundaries of the commonwealth.
SURVEYORAn individual licensed and registered under the laws of the commonwealth of Pennsylvania to engage in the practice of land surveying. A surveyor shall not perform engineering as defined by this chapter, unless the surveyor is also a registered engineer.
SWALEA low-lying stretch of land which gathers or carries surface water runoff. Usually of a trapezoid shape with gentle side slopes.
TERRESTRIALLiving or growing on land that is not normally flooded or saturated.
TOP OF STREAMBANKFirst substantial break in slope between the edge of the bed of the stream and the surrounding terrain. The top of streambank can either be a natural or constructed (that is, road or railroad grade) feature, lying generally parallel to the watercourse.
TOPOGRAPHIC MAPA map showing the elevations of the ground by contours or elevations, including all existing topographic features such as streams, roads, streets, existing facilities, and improvements, as specified herein.
TOPSOILSurface soil and subsurface soil which presumably is fertile soil and ordinarily rich in organic matter or humus debris.
TOTAL NITROGEN (TN)A measure of all organic and inorganic nitrogen forms in a water sample. Functionally, TN is equal to the sum of TKN and NO3 + NO2-N.
TOTAL PHOSPHORUS (TP)A measure of the total phosphorus in a water sample, including organic and inorganic phosphorus in particulate and soluble forms.
TRACTIVE FORCEThe total cross-sectional force experienced by a rigid channel or conduit as a result of channel flow (expressed in units of force per length). This force tends to displace soil particles, rocks and channel liners in the downstream direction and must be resisted by friction or by structural anchors. The tractive force is equal to the unit tractive force multiplied by the wetted perimeter of the conduit.
TRANSITION ZONEThe area between habitats or ecosystems (see ecotones). Frequently, transition zone is used to refer to the area between uplands and wetlands. In other cases, wetlands are referred to as transitional areas between uplands and aquatic ecosystems.
TRANSMISSIVITY (IN-PLANE FLOW CAPACITY)Rate that water can be made to flow through the cross section of a thin layer or conduit under the influence of a unit hydraulic gradient. Measured as a volumetric rate per unit width (e.g., square feet meters per minute, or gallons per minute per foot). Equal to the hydraulic conductivity times the thickness of the layer or conduit.
TRANSPIRATIONThe transport of water vapor from the soil to the atmosphere through growing plants.
TYPE II RAINFALL DISTRIBUTIONStandard NRCS twenty-four-hour rainfall distribution which applies to the state of Pennsylvania. The distribution allocates rainfall as a percentage of total rainfall over discrete time intervals.
UNIFORMITY COEFFICIENTA measure of the range in particle sizes associated with a granular mixture. Materials with the lowest uniformity coefficients are most uniform. Uniform materials are also called open graded materials. If the uniformity coefficient is less than four or five the material is considered uniform in particle size. The uniformity coefficient is computed as follows:
Cu = (D60/D10) |
D60 is the sieve opening size through which 60% of the layer material will pass. D10 is the sieve opening size through which 10% of the layer material will pass. |
The stress (expressed in units of force per area) induced by open channel flow on the bottom and sides of its conduit or channel. This stress is responsible for sediment erosion and the downstream transport of streambed materials. The average unit force acting on a channel cross-section is equal to the product of the unit weight of water, the slope of the channel, and the hydraulic radius of the flow.
UPLANDAn area that is not an aquatic, wetland, or riparian habitat. An area that does not have the hydrologic regime necessary to support hydrophytic vegetation.
USDAUnited States Department of Agriculture.
USEThe specific purpose for which land or a building is designed, arranged, intended or for which it is or may be occupied or maintained. The term "permitted use" or its equivalent shall not be deemed to include any nonconforming use.
UTILITYAny agency that provides the public with electricity, gas, heat, water, sewer, communications, and transportation. Includes public utilities, though not all services included within this definition are public utilities.
VARIANCEA variance is a modification of the strict terms of zoning regulations where such modification will not be contrary to the public interest and where, owing to physical conditions peculiar to the property and not the result of the action of the applicant, a literal enforcement of the regulations would result in unnecessary and undue hardship.
VARIATIONA variation is a modification of the strict terms of the floodplain regulation where such modification shall not be contrary to the public interest and where, owing to physical conditions peculiar to the property and not the result of the action of the applicant, a literal enforcement of this regulations would result in unnecessary and undue hardship. A variation is similar to a variance but is held to a lower test of hardship.
WAIVERNo waiver will be given for stormwater management. A written variance with regard to fencing around shallow detention ponds can be submitted if it meets the three criteria established in the stormwater ordinance, criteria for detention facilities.
WALLThe vertical exterior surface of a building. Also, the vertical interior surfaces that divide the space within a building into rooms.
WATER QUALITY DESIGN STORMBenchmark rainfall event, used to develop criteria for the design of water quality BMPs. Water quality design storms are used to size BMPs that are intended to achieve specific quality treatment objectives. Criteria based on water quality storms generally require that the design treatment efficiency be achieved during the water quality design storm and all smaller events. Complete specification of the storm includes rainfall depth in inches, return frequency and storm duration. The distribution of rainfall in Pennsylvania is a Type II rainfall distribution. See Section
5.3 of the PA BMP Handbook.
The volume set aside within a BMP to detain storm runoff. The detained water is released over an extended period of time. The water quality storage is frequently expressed as a multiple of the water quality volume.
WATER QUALITY VELOCITYThe maximum flow velocity encountered in a water quality BMP during the course of the water quality design storm.
WATER QUALITY VOLUMEThe total volume of runoff which is delivered to the inlet of a water quality BMP during the course of the water quality design storm.
WATER SUPPLY AND DISTRIBUTION SYSTEM, COMMUNITYA system for supplying and distributing water from a common source to two or more dwellings and other buildings within a subdivision, neighborhood, or whole community, the total system being publicly or privately owned.
WATER SURVEYAn inventory of the source, quantity, yield, use of groundwater and of surface water resources within a municipality.
WATERCOURSEAny channel of conveyance of surface water having defined bed and banks, whether natural or artificial, with perennial or intermittent flow.
WATERS OF THE COMMONWEALTHAny and all rivers, streams, creeks, rivulets, impoundments, ditches, water courses, 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 the commonwealth of Pennsylvania.
WATERSHEDThe entire region or area drained by a river, watercourse, or other surface water whether natural or artificial of the commonwealth. 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 PLANThe plan for managing stormwater runoff throughout a designated watershed adopted by Blair County as required by the Pennsylvania Stormwater Management Act.
WATTLESFence or barrier constructed of interwoven twigs and branches used to stabilize soil from erosive forces.
WEIRA device used to control and measure water flow.
WEIR GATEWater-control device used to adjust water levels and measure flows simultaneously.
WET SWALEThe wet swale also consists of a broad open channel capable of temporarily storing the water quality treatment volume (also a volume-based sizing criteria), but does not have an underlying filtering bed. The wet swale is constructed directly within existing soils and may or may not intercept the water table. Like the dry swale, the water quality volume within the wet swale should be stored for approximately 24 hours.
WETLANDAn area that is inundated or saturated by surface water or groundwater at a frequency, duration, and depth 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.
WILTING POINTQuantity of water which will not be removed from soil under normal conditions of evaporation and plant transpiration. Usually measured as the moisture content (by volume) in soil with a capillary tension of 15 bars.
ZONATIONThe development of a visible progression of plant or animal communities in response to a gradient of water depth or some other environmental factor.
