[Ord. 8/12/1999, § 2.2]
All words and terms not defined herein shall be used with a
meaning of standard usage.
ACCELERATED EROSION
The removal of the surface of the land through the combined
action of man's activities and natural processes at a rate greater
than would occur because of the natural processes alone.
ADVERSE IMPACT
Any deleterious effect on surface waters or groundwater or
wetlands, including their quality, quantity, surface area, species
composition, aesthetics or usefulness for human use or consumption
or natural uses which are or may potentially be harmful or injurious
to human health, safety, general welfare, property, to biological
productivity, diversity or stability or which unreasonably interfere
with the enjoyment of life or property, including outdoor recreation.
ALLUVIAL SOILS
Those soils customarily associated with historical floodplains,
typically coarse and unconsolidated gravel and sand, delineated pursuant
to the Columbia County, Pennsylvania Soil Survey, as prepared and
periodically updated or supplemented by the United States Department
of Agriculture.
ALTERATION
As applied to land, a change in topography as a result of
excavating or moving soil and rock from one location to another, also
the changing of surface conditions by causing the surface to be more
or less impervious; land disturbance.
APPLICANT
A landowner or landowner's agent or developer who has
filed an application for development approval or approval to engage
in any activities regulated under this Part, including heirs, successors
and assigns.
BASE FLOW
That portion of stream flow which is not due to storm runoff
and is supported by groundwater seepage into a channel.
BIOFILTRATION
The use of a series of vegetated swales to provide filtering
treatment for stormwater as it is conveyed through the channel or
buffer strips of land to filter storm runoff during overland flow.
The swales may be but are not limited to grass, emergent wetlands
or high marsh plants.
BMP
Best management practices, in the design and application
of stormwater structures, facilities and nonstructural solutions or
managerial practices, or a combination thereof, to maintain or improve
the water quality of surface runoff; structural may include, but are
not limited to, basins or seepage pits; nonstructural may include,
but are not limited to, vegetated filter strips, riparian forest buffers;
managerial practices may include, but are not limited to, maintenance
techniques.
BUFFER STRIPS
Strips of grass or other close-growing vegetation used to
separate a waterway from an intensive land use area to trap or filter
sediments from the storm runoff.
CHANNEL
A perceptible natural or man-made waterway which periodically
or continuously contains moving water having a definite bed and banks
which confine the flow of water.
CHECK DAM
A log or gabion structure placed perpendicular to a stream
to enhance aquatic habitat; an earthen or log structure used in grass
swales to reduce water velocities, promote sediment deposition and
enhance filtration.
CISTERN
An underground reservoir or tank for storing rainwater.
CLEARING
The removal of trees, brush or other vegetative cover from
the land but shall not mean the ordinary mowing of grass or pasture
land or the cutting of fields to control weeds and brush.
CLOSED OR UNDRAINED DEPRESSION
In karst geologic conditions, a distinct bowl-shaped depression
in the land surface; size and amplitude are variable; drainage is
internal with no perceivable opening in the land surface (i.e., sinkhole).
CONTRIBUTING AREA
That drainage area which flows toward and through or into
a given development site but excluding runoff from that site itself.
CULVERT
A pipe, conduit or similar structure, including appurtenant
works, which carries surface water under or through an embankment,
fill or roadbed.
DAM
An artificial barrier, together with its appurtenant works,
constructed for the purpose of impounding or storing water or another
fluid or semifluid, or a refuse bank, fill or structure for highway,
railroad or other purposes which does or may impound water or another
fluid or semifluid.
DESIGN STORM
The magnitude of precipitation from a storm event measured
in probability of occurrence (e.g., twenty-five-year storm) and duration
(e.g., twenty-four-hour) used in computing and designing stormwater
management control systems.
DETENTION BASIN
An impoundment structure designed to retard stormwater runoff
by temporarily storing the runoff and releasing it at a predetermined
and designed rate, which drains completely after a storm event and
is not intended to create a permanent pool of water.
DEVELOPER
Any landowner, agent of such landowner, lessee or tenant
with permission of such landowner, whether an individual person, partnership,
association, corporation, cult, sect or other entity, who makes or
causes to be made a subdivision of land or land development.
DEVELOPMENT SITE
The specific tract or parcel of land for which a regulated
activity is proposed.
DIVERSION TERRACE
A 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.
DRAINAGE AREA
Area of land contributing runoff to a single point measured
in a horizontal plane, which is enclosed by higher ground or a ridgeline.
DRAINAGE EASEMENT
A grant by a landowner to a grantee, of the right to use
the landowner's land for stormwater management purposes, defined
by a plotted center line and designated width and including the right
of access by the grantee to maintain the watercourse, prohibiting
the blockage of the watercourse or other uses by the grantee(s) inconsistent
with the drainage rights granted; preferably recorded in the Office
of the Columbia County Recorder of Deeds.
DRAINAGE PLAN
The documentation of the stormwater management system, if
any, to be used for a given development site, the required contents
of which are established in this Part.
ENGINEER
Professional engineer registered with the Commonwealth of
Pennsylvania.
EROSION
The removal of soil particles by action of water, wind, ice
or other geologic agents.
EVAPOTRANSPIRATION
The combined loss or movement of moisture from the earth
surface through evaporation and the release of moisture by plants.
FLOOD
A temporary inundation of normally dry land areas.
FLOOD, ONE-HUNDRED-YEAR
A flood that in the average is likely to occur once every
100 years (i.e., that has a 1% chance of occurring each year, although
the flood may occur in any year).
FLOODPLAIN
1.
A relatively flat or low land area adjoining a river, stream,
or watercourse which is subject to partial or complete inundation.
2.
An area subject to the unusual and rapid accumulation of runoff
of surface waters from any source.
FLOODWAY
The channel and those portions of the adjoining floodplains
which are reasonably required to carry and discharge the one-hundred-year
frequency flood. Unless otherwise specified the boundary of the floodway
is as indicated on maps and flood insurance studies for the Township.
In an area where no flood insurance studies have defined the boundary
of the one-hundred-year frequency floodway it is assumed, absent evidence
to the contrary, that the floodway extends from the stream overland
to 50 feet beyond the top of the bank of the stream.
FOREST MANAGEMENT OPERATIONS
All activities connected with growing and harvesting of forest
products, including the site preparation, cultivation, and logging
of trees, and the construction and maintenance of access and haul
roads.
FREEBOARD
A factor of safety usually expressed in feet above a flood
level for purposes of floodplain management. "Freeboard" tends to
compensate for the many unknown factors that could contribute to flood
heights greater than the height calculated for a selected size flood
and floodway conditions, such as wave action, bridge openings and
the hydrological effect of urbanization of the watersheds.
GEOLOGIC FORMATION
The basic or fundamental rock stratigraphic unit in the local
classification of rocks, consisting of a body of rock (usually a sedimentary
stratum or strata) having some degree of homogeneity or similar features,
used in mapping the geology of an area.
GRADING
Any act by which soil is cleared, stripped, stockpiled, scarified,
filled or any combination thereof for the purpose of changing the
natural slope
GROUNDWATER RECHARGE
Replenishment of existing natural underground water supplies
by process of stormwater infiltration into the soil or geologic cavities.
IMPERVIOUS AREA
Impervious surfaces, such as pavement or rooftops, which
prevent the infiltration of water into the soil; the cumulative total
area of all impervious surfaces in a given development proposal.
INFILTRATION STRUCTURE
A structure designed to direct runoff into the ground, such
as french drains, seepage pits or seepage trenches.
INTERCEPTION
Precipitation which is retained by the leaves and stems of
vegetation.
KARST
A 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.
LAND DEVELOPMENT
The improvement of one lot or two or more contiguous lots,
tracts or parcels of land for any purpose involving:
1.
A group of two or more residential or nonresidential buildings,
whether proposed initially or cumulatively or a single nonresidential
building on a lot or lots regardless of the number of occupants or
tenure.
2.
The division or allocation of land or space, whether initially
or cumulatively, between or among two or more existing or prospective
occupants by means of, or for the purpose of, streets, common areas,
leaseholds, condominiums, building groups or other features.
3.
A (division) subdivision of land (into lots for the purpose
of conveying such lots singly or in groups to any person, partnership
or corporation for the purpose of the erection of buildings by such
person, partnership or corporation).
LAND DISTURBANCE
Any 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.
LANDOWNER
The 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 is
authorized under the lease to exercise the rights of the landowner
or other person having a proprietary interest in land.
LEVEL SPREADER
A device used to spread out stormwater runoff uniformly over
the ground surface as sheet flow (i.e., not through channels) for
the purpose of preventing concentrated, erosive flows and to enhance
infiltration.
LOW FLOW CHANNEL
An 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.
MUNICIPALITY
The Township of Montour, Columbia County, Pennsylvania.
NRCS
Natural Resources Conservation Service of the United States
Department of Agriculture; formerly the SCS (Soil Conservation Service).
ON-SITE STORMWATER MANAGEMENT
The design and construction of systems and facilities to
control stormwater within an immediate or proposed development.
OPEN CHANNEL
A drainage element in which stormwater flows with an open
surface, including, but not limited to, natural and man-made watercourses,
swales, rills, runs, streams, ditches and canals.
PA DEP
Pennsylvania Department of Environmental Protection; formerly
PA DER.
PEAK DISCHARGE
The maximum rate of flow of stormwater at a given point and
time resulting from a specified storm event.
PIPE
A culvert, closed conduit or similar structure (including
appurtenances) that conveys stormwater.
PMF (PROBABLE MAXIMUM FLOOD)
The flood that may be expected from the most severe combination
of critical meteorologic and hydrologic conditions that are reasonably
possible in an area. The PMF is derived from the probable maximum
precipitation (PMP) as determined on the basis of data obtained from
the National Oceanographic and Atmospheric Administration (NOAA).
POROUS PAVING
An open graded asphalt or reticular concrete, geosynthetic
interlocking block or web structural system or other material which
allows water to pass through and infiltrate into the ground.
REGULATED ACTIVITIES
Actions or proposed actions that would have an impact on
stormwater runoff flow pattern, volume, rate and/or velocity that
are to be controlled under this Part.
RELEASE RATE
The percentage of the pre-development peak discharge of runoff
from a subarea to which the post-development peak discharge must be
reduced to protect downstream areas.
RETENTION
The holding of runoff in a basin without release, except
by means of evaporation, infiltration or emergency bypass.
RETENTION BASIN
A basin in which the runoff from a given storm event is stored
and is not discharged into the downstream drainage system during the
storm event; a pool of water is retained.
RETURN PERIOD
The average interval, in years, within which a storm of a
given magnitude can be expected to recur.
RUNOFF
That part of precipitation which flows over the land and
is not absorbed into the ground.
RUNOFF CHARACTERISTICS
The surface components of a watershed, including, but not
limited to, vegetation, slopes and man-made alterations to the surface
that affect the rate, amount and direction of stormwater runoff.
SCS
U.S. Department of Agriculture, Soil Conservation Service
[now the Natural Resources Conservation Service (NRCS)].
SEDIMENT BASIN
A barrier, dam, retention or detention basin located and
designed to retain rock, sand, gravel, silt or other water-transported
material.
SEDIMENTATION
The process by which mineral and/or organic matter is transported
and deposited by the action of water, wind, ice or gravity as a product
of erosion.
SEEPAGE PIT/SEEPAGE TRENCH
An excavated area filled with loose rocks or stone or similar
material into which surface water or roof runoff is directed for infiltration
into the ground.
SEMIPERVIOUS AREA
The cumulative total area of all semipervious surfaces in
a given development proposal.
SEMIPERVIOUS SURFACE
A surface which limits the percolation of water into ground,
such as a compacted stone driveway.
SHEET FLOW
Runoff which flows over the ground surface as a thin even
layer not concentrated in a channel.
SINKHOLE
A 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 or
cracking of the ground surface and downward movement of the soil into
bedrock voids.
SOIL-COVER COMPLEX METHOD
A method of runoff computation developed by the SCS that
is based on relating soil type and land use/cover to a runoff parameter
called a curve number (CN) as explained in the SCS publication "Urban
Hydrology for Small Watersheds," Technical Release No. 55, as revised.
SPILLWAY
A depression in the embankment of a basin or pond that is
used to pass peak discharges greater than the maximum design storm
controlled by the basin or pond.
STABILIZATION
The prevention of soil movement by any of the various structural
means.
STORM SEWER
A 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
The drainage runoff from the surface of the land resulting
from precipitation, snow or ice melt.
STORMWATER MANAGEMENT
For quantitative control, a system of vegetative and structural
measures that control the increased volume and rate of surface runoff
caused by man-made changes to the land. For qualitative control, a
system of vegetative, structural, and other measures that reduce or
eliminate pollutants that might otherwise be carried by surface runoff.
STORMWATER MANAGEMENT FACILITY
Any structure, natural or man-made, that, due to its condition,
location, design or construction, conveys, stores or otherwise affects
stormwater runoff. Typical stormwater management facilities include,
but are not limited to, detention and retention basins, open channels,
level spreaders, storm sewer pipes, seepage trenches and infiltration
structures.
STORMWATER MANAGEMENT PLAN
For a watershed, the plan for managing runoff in a named
watershed adopted by the Columbia County Commissioners and/or the
Montour County Commissioners as required by Act 167 of 1978, P.L.
864, known as the Pennsylvania Storm Water Management Act, 32 P.S.
§ 680.1 et seq.
STORMWATER MANAGEMENT SYSTEM
For quantitative control, a system of vegetative and structural
measures that together control the increased volume and rate of surface
runoff caused by man-made changes to the land, including any structure,
natural or man-made, that, due to its condition, location, design
or construction, conveys, stores or otherwise affects stormwater runoff.
Typical stormwater management facilities include, but are not limited
to, detention and retention basins, open channels, level spreaders,
storm sewer pipes, seepage trenches and infiltration structures. For
qualitative control, a system of vegetative, structural and other
measures that reduce or eliminate pollutants that might otherwise
be carried by surface runoff.
STREAM ENCLOSURE
A bridge, culvert or other structure in excess of 100 feet
in length upstream to downstream which encloses a regulated water
of this commonwealth.
SUBAREA
The smallest drainage unit of a watershed for which stormwater
management criteria have been established in the Stormwater Management
Plan for a given watershed.
SUBDIVISION
The division or redivision of a lot, tract or parcel of land
by any means into two or more lots, tracts, parcels or other division
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 residential
dwelling, shall be exempted.
SWALE
A low-lying vegetated stretch of land or wide shallow ditch,
either grass or paved, which collects and carries surface water runoff.
TOPOGRAPHY
The 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.
TOWNSHIP
The Township of Montour, Columbia County, Pennsylvania. For
purposes of this Part, actions or decisions shall be official upon
authorization by the Board of Township Supervisors.
USDA
The United States Department of Agriculture.
WAIVER
The determination by the Board of Township Supervisors upon
recommendation by the Township Planning Commission that a particular
requirement or design standard is not necessary given the site-specific
conditions and proposed development or land use; or that such requirement
or design standard may be modified for that particular site and development
or land use without detriment to the intent and purpose of this Part.
WATER COURSE
A channel or conveyance of surface water having defined bed
and banks, natural or artificial, with perennial or intermittent flow.
WATERSHED
The entire region or area drained by a river or other body
of water, whether natural or artificial; a drainage basin or subbasin.
WETLAND
Those areas that are inundated or saturated by surface water
or groundwater at a frequency and duration sufficient to support,
and that under normal circumstances do support, a prevalence of vegetation
typically adapted for life in saturated soil conditions, commonly
known as hydrophytic vegetation. Wetlands generally include swamps,
marshes, bogs and similar areas and may be identified by hydrology,
hydric soils and hydrophytic vegetation.