[Ord. 114, 10/13/1996, Art. V, § 2]
The following words and phrases, when used in this Part, shall have, unless the context clearly indicates otherwise, the meanings given to them in this section. All words and terms not defined herein shall be used with a meaning of standard usage.
ALLUVIAL SOILSThose areas delineated pursuant to the Northumberland County, Pennsylvania, Soil Survey, and all revisions.
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 a zoning permit or subdivision approval.
CARBONATEA sediment formed by the organic or inorganic precipitation of mineral compounds characterized by the fundamental chemical ion CO3. The principal element in limestone and dolomite strata.
CHANNELA perceptible natural or artificial waterway which periodically or continuously contains moving water having a definite bed and banks which 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 minute area.
DESIGN STORMThe magnitude of precipitation from a storm event measured in probability of occurrence (e.g., ten-year storm) and duration (e.g. twenty-four-hour), and used in designing stormwater management control systems.
DETENTION BASINA pond or basin designed to retard stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate. A detention pond may be designed to drain completely after a storm event (dry pond), or it may be designed to contain a permanent pool of water (wet pond).
DEVELOPERA person or persons, partnership, association, corporation or other entity, or any responsible person therein or agent thereof, who undertakes the activities covered by this Part.
EASEMENTA recorded agreement of right-of-way granted, but not dedicated, for limited use of private land for a public or quasi-public purpose, identified on the final plan, and within which the owner of the property shall not erect any permanent structures, but shall have the right to make any other use of the land which is not inconsistent with the rights of the grantee.
EROSIONThe removal of soil, stone and other surface materials by the action of natural elements.
FLOODPLAINA floodplain or flood hazard area is that land, within the Township, adjoining any watercourse subject to a one-hundred-year recurrence interval flood as delineated by a study prepared by any federal, state or county agency; a registered professional engineer experienced in the preparation of hydrological and hydraulic studies and the determination of flood boundary lines; or the area denoted as having alluvial soils on the most recent soil survey of the Soil Conservation Service, United States Department of Agriculture.
GABIONA large rectangular box of heavy gage wire mesh which holds large cobbles and boulders. Used in streams and ponds to change flow patterns, stabilize banks or prevent erosion.
GEOLOGIC FORMATIONThe basic or fundamental rock stratigraphic unit in the local classification of rocks, consisting of a body of rock (usually a sedimentary stratum or strata but also igneous or metamorphic) generally characterized by some degree of internal lithologic homogeneity or distinctive lithologic features (such as chemical composition, structures, textures, gross aspect of fossils or time of deposition.) Typically used for mapping the geology of an area.
GEOLOGIC MEMBERA rock stratigraphic unit which is subordinate (a subject) of a formation. This unit is not necessarily mappable and is usually a unified subdivision of local extent that may or may not be contained in more than one foundation.
GHOST LAKEA body of standing water occurring in a sinkhole or closed depression of a Karst region that is usually visible after sufficient precipitation has occurred. They may form from slow permeability of soils, rises in the water table or the development of a natural liner of slow permeable clays or soils.
GRADINGThe act the excavating and/or filling land for the purposes of changing natural slope.
IMPERVIOUS AREAImpermeable surfaces, such as pavement on rooftops, which limits the infiltration of water into the soil, as outlined in Table A-2 of Appendix A, § I.
INFILTRATION STRUCTUREA structure designed to direct runoff into the ground, such as french drains, seepage pits or seepage trenches.
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 DISTURBANCEAny activity involving grading, tilling, digging or filling of ground or stripping of vegetation or any other activity which causes land to be exposed to erosion.
LEVEL SPREADERA device used to spread out stormwater runoff uniformly over the ground surface as sheet flow (i.e., not through channels). The purpose of level spreaders are to prevent concentrated, erosive flows from occurring, and to enhance infiltration.
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 FLOW CHANNELAn incised or paved channel from inlet to outlet in a dry basin which is designed to carry low runoff flows and/or base flow directly to the outlet without detention.
MUNICIPALITYThe Township of Ralpho, Northumberland County, Pennsylvania.
PEAK DISCHARGEThe maximum rate of flow of water at a given point and time resulting from a storm event.
REGISTERED PROFESSIONALAn individual registered in and licensed by the State of Pennsylvania including, for the purposes of this Part, land surveyors, landscape architects, architects and engineers.
RETENTION BASINA basin in which the runoff from a given flood event is stored and is not discharged into the downstream drainage system during the flood event.
RIPRAPA combination of large stone, cobbles and boulders used to line channels, stabilize banks, and reduce runoff velocities.
SCSSoil Conservation Service, U.S. Department of Agriculture.
SEDIMENTATIONThe process by which mineral or organic matter is accumulated or deposited by the movement of water.
SEDIMENTATION BASINA barrier, dam, retention or detention basin located and designed to retain rock, sand, gravel, silt or other water transported material.
SHEET FLOWRunoff which flows over the ground surface as a thin, even layer, not concentrated in a channel. Flow depth is generally 0.1 foot or less.
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.
SINKHOLE FLOODPLAINThe area inundated by the one-hundred-year, twenty-four-hour storm, assuming no drainage from the sinkhole or closed depression based upon anticipated runoff volumes with maximum development permitted by zoning within the catchment area or area draining to the sinkhole.
SOIL COVER COMPLEX METHODA method of runoff computation developed by SCS, and found in its publication "Urban Hydrology for Small Watersheds," Technical Release No. 55, as revised.
STORM SEWERA system of pipes or other conduits which carries intercepted surface runoff, street water and other wash water or drainage, excluding domestic sewage and industrial wastes.
STORMWATERThe drainage runoff from the surface of the land resulting from precipitation, snow or ice melt.
STRATATabular 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.
SWALEA low-lying vegetated stretch of land or wide shallow ditch, usually grassed or paved, which gathers or carries surface water runoff.
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.
USDAUnited States Department of Agriculture.
WATERSHEDThe entire region or area drained by a river or other body of water, whether natural or artificial, a drainage basin or subbasin.
WETLANDSThose areas defined in the "Federal Manual for Identifying and Delineating Jurisdictional Wetlands," latest edition.