As used in this chapter, the following terms shall have the meanings
indicated:
AGRICULTURAL ACTIVITIES
Activities associated with agriculture such as agricultural
cultivation, agricultural operation, and animal heavy use areas. This
includes the work of producing crops including tillage, land clearing,
plowing, disking, harrowing, planting, harvesting crops or pasturing
and raising of livestock and installation of conservation measures.
Construction of new agricultural-related buildings up to 20,000 square
feet in size on land zoned agricultural that have properly sized and
installed roof sumps in accordance with this chapter are considered
agricultural activities. All other building or impervious area is
not considered agricultural activities.
ALTERATION
As 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.
APPLICANT
A subdivider, landowner or developer (including his heirs,
successors, or assigns) who has filed an application for approval
to engage in any regulated activity as defined in this chapter.
BASIN FLOOD TEST
A test method for evaluating stormwater facility infiltration
rates. A basin flood test involves flooding the stormwater facility
to a minimum depth of one foot or the capture depth if less than one
foot, and measuring the observed change in ponded depth with time.
Sufficient data must be collected during the test to demonstrate that
the basin, when flooded to the capture depth, will drain in accordance
with basin empty time requirements.
BMP (BEST MANAGEMENT PRACTICE)
Activities, facilities, designs, measures, or procedures
used to manage stormwater impacts from regulated activities, to meet
state water quality requirements, to promote groundwater recharge,
and to otherwise meet the purposes of this chapter. Stormwater BMPs
are commonly grouped into one of two broad categories or measures:
"structural" or "nonstructural." In this chapter, nonstructural BMPs
or measures refer to operational and/or behavior-related practices
that attempt to minimize the contact of pollutants with stormwater
runoff, whereas structural BMPs or measures are those that consist
of a physical device or practice that is installed to capture and
treat stormwater runoff. Structural BMPs include, but are not limited
to, a wide variety of practices and devices, from large-scale retention
ponds and constructed wetlands, to small-scale underground treatment
systems, infiltration facilities, filter strips, low-impact design,
bioretention, wet ponds, permeable paving, grassed swales, riparian
or forested buffers, sand filters, detention basins, and manufactured
devices. Structural stormwater BMPs are permanent appurtenances to
the project site. Stormwater structures, facilities and techniques
to maintain or improve the water quality of surface runoff.
BUFFER AREA
Area that is protected from development in order to prevent
degradation of the water body or water quality.
CAPTURE DEPTH
Depth of water ponded in a surface or subsurface basin that
is: 1) below the lowest controlling outflow orifice; and 2) is either
allowed to evaporate, infiltrate, or be discharged through a spillway
at a negligible rate (typically through basin underdrains). Outflow
devices intended to drain the capture depth are not considered controlling
outflow orifices for the purpose of this definition.
CAPTURE VOLUME
The volume of runoff captured from a given area in a surface
or subsurface basin that is: 1) below the lowest controlling outflow
orifice; and 2) is either allowed to evaporate, infiltrate, or be
discharged from a spillway at a negligible rate (typically through
basin underdrains). Outflow devices intended to drain the capture
depth are not considered controlling outflow orifices for the purpose
of this definition.
CARBONATE
A 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.
CATION EXCHANGE CAPACITY (CEC)
A measure of the soil's ability to hold exchangeable
positively charged ions. It is a characteristic related to a soils
ability to treat pollutants in infiltrating water. Cation Exchange
Capacity is expressed as meq/100 g which is numerically equivalent
to centimoles of charge per kilogram of exchanger (cmol(+)/kg).
CHANNEL
A 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 DEPRESSION
In a Karst geologic area a distinct bowl-shaped depression
in the land surface; size and amplitude are variable; drainage is
internal. It differs from a sinkhole in that the ground surface is
unbroken and usually occurs in greater density per unit area.
CREDITS
A deduction from the required amount. In this chapter, implies
reduction of required water quality volumes due to using a recommended
practice.
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.
DEP
The Pennsylvania Department of Environmental Protection.
DESIGN STORM
The magnitude and temporal distribution of precipitation
from a storm event measured in probability of occurrence (e.g., a
five-year storm) and duration (e.g., 24 hours), used in the design
and evaluation of stormwater management systems.
DESIGNEE
The agent of the Township involved with the administration,
review or enforcement of any provisions of this chapter by contract
or memorandum of understanding.
DETENTION BASIN
An impoundment structure designed to manage stormwater runoff
by temporarily storing the runoff and releasing it at a predetermined
rate.
DEVELOPER
A person, partnership, association, corporation, or other
entity, or any responsible person therein or agent thereof, that undertakes
any regulated activity of this chapter.
DEVELOPMENT SITE
The specific tract of land for which a regulated activity
is proposed.
DOLOMITE
A.
A mineral consisting of calcium magnesium carbonate found as
compact limestone; or
B.
Limestone or marble rich in magnesium carbonate.
DOWNSLOPE PROPERTY LINE
That portion of the property line of the lot, tract, or parcels
of land being developed located such that overland or pipe flow from
the site would be directed towards it.
DRAINAGE CONVEYANCE FACILITY
A stormwater management facility designed to transmit stormwater
runoff and shall include streams, channels, swales, pipes, conduits,
culverts, storm sewers, and similar structures.
DRAINAGE EASEMENT
A right granted by a landowner allowing the use of private
land for stormwater management purposes.
DRAINAGEWAY
The natural or man-made path of surface water from a given
area.
EARTH DISTURBANCE ACTIVITY
A construction or other human activity which disturbs the
surface of the land, including, but not limited to: clearing and grubbing;
grading; excavations; embankments; road maintenance; building construction;
and the moving, depositing, stockpiling, or storing of soil, rock,
or earth materials, including the placement of fill material on existing
ground.
EROSION
The movement of soil particles by the action of water, wind,
ice, or other natural forces.
EXFILTRATION
The process by which water or moisture moves from a subsurface
trench, bed, or other feature into the subsoil. Exfiltration is best
measured by a soil's percolation rate.
EXISTING CONDITIONS
The initial condition of a project site prior to the proposed
construction.
FLOOD
A general but temporary condition of partial or complete
inundation of normally dry land areas from the overflow of streams,
rivers, and other waters of this commonwealth.
FLOODPLAIN
A relatively flat or low land area which is subject to partial
or complete inundation from an adjoining or nearby stream, river,
or watercourse; and/or any area subject to the unusual and rapid accumulation
of surface waters from any source including areas mapped on the Department
of Housing and Urban Development, Federal Insurance Administration
Flood Hazard Boundary Maps.
FLOODWAY
The channel of the watercourse and those portions of the
adjoining floodplains that 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 provided by FEMA. In an area where no FEMA maps or 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 to 50 feet from the top of the bank of the
stream.
FOREST MANAGEMENT/TIMBER OPERATIONS
Planning and activities necessary for the management of forestland.
These include timber inventory and preparation of forest management
plans, silvicultural treatment, cutting budgets, logging road design
and construction, timber harvesting, site preparation and reforestation.
FREEBOARD
A vertical distance between the elevation of the design high-water
and the top of a dam, levee, tank, basin, or diversion ridge. The
space is required as a safety margin in a pond or basin.
GRASSED WATERWAY
A natural or constructed waterway, usually broad and shallow,
covered with erosion-resistant grasses, used to convey surface water.
HYDROLOGIC SOIL GROUP (HSG)
Infiltration rates of soils vary widely and are affected
by subsurface permeability as well as surface intake rates. Soils
are classified into four HSGs (A, B, C and D) according to their minimum
infiltration rate, which is obtained for bare soil after prolonged
wetting. The NRCS defines the four groups and provides a list of most
of the soils in the United States and their group classification.
The soils in the area of the development site may be identified from
a soil survey report that can be obtained from local NRCS offices
or conservation district offices. Soils become less pervious as the
HSG varies from A to D (NRCS3,4).
IDF
Intensity duration frequency curve.
IMPERVIOUS SURFACE (AREA)
A surface that prevents the 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 streets or sidewalks. Decks,
parking areas, and driveway areas are not counted as impervious areas
if they do not prevent infiltration.
IMPOUNDMENT
A retention or detention basin designed to retain stormwater
runoff and release it at a controlled rate.
INFILTRATION RATE
The infiltration rate of a soil is related to the soil's
final infiltration capacity and represents the rate at which water
enters the soil/air interface at the top of the soil profile. Infiltration
rates are measured in units of length/time.
INLET
A surface connection to a closed drain. A structure at the
diversion end of a conduit. The upstream end of any structure through
which water may flow.
INTERCEPTOR
A channel, berm, or dike constructed across a slope for the
purpose of intercepting stormwater, reducing the velocity of flow,
and diverting it to outlets where it may be disposed.
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 (from AGI,
Glossary of Geology, 1972).
LAND DEVELOPMENT
Inclusive of any or all of the following meanings:
A.
The improvement of one lot or two or more contiguous lots, tracts,
or parcels of land for any purpose involving: a) a group of two or
more buildings; or b) the division or allocation of land or space
between or among two or more existing or prospective occupants by
means of, or for the purpose of, streets, common areas, leaseholds,
condominiums, building groups, or other features;
C.
Development in accordance with Section 503(1.1) of the Pennsylvania
Municipalities Planning Code.
LAND USE
The primary application employed in an area.
LAND/EARTH DISTURBANCE
Any activity involving grading, tilling, digging, or filling
of ground or stripping of vegetation or any other activity that causes
an alteration to the natural condition of the land.
LIMESTONE
A rock that, by accumulation of organic remains, consists
mainly of calcium carbonate.
LINEAMENTS
Straight 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.
MAIN STEM (MAIN CHANNEL)
Any stream segment or other runoff conveyance facility used
as a reach in the Spring Creek hydrologic model.
MINIMALLY DISTURBED AREA
Site areas where previous or proposed activities have a negligible
impact on the natural soil structure. These areas include protected
areas or areas that are restored in accordance with procedures for
minimizing total disturbed areas and minimizing soil compaction as
defined in the current version of the Pennsylvania Stormwater Best
Management Practices Manual.
MINIMUM ALLOWABLE DISCHARGE
In relation to this Stormwater Management Ordinance, the
minimum rate that can be discharged for any drainage area for design
storm events up to and including the ten-year event regardless of
the modeled predevelopment runoff estimate.
NATURAL AREA CONSERVATION
Protection of a natural area during development for its water
quality or recharge enhancing abilities.
OUTFALL
Point where water flows from a conduit, stream, or drain.
OUTLET
Points of water disposal from a stream, river, lake, tidewater
or artificial drain.
PADEP
Pennsylvania State Department of Environmental Protection.
PADOT
Pennsylvania State Department of Transportation.
PEAK DISCHARGE
The maximum rate of stormwater runoff from a specific storm
event.
PERCOLATION RATE
The rate at which water moves through a soil profile. Percolation
rates are measured in units of time/length.
PIPE
A culvert, closed conduit, or similar structure (including
appurtenances) that conveys stormwater.
POINT DISCHARGE
The discharge from a pipe or channel that concentrates runoff
at a single area.
PROJECT SITE
The specific area of land where any regulated activities
in the Township are planned, conducted, or maintained.
RECHARGE VOLUME
The volume of water that is required to be recharged from
developed sites.
REGULATED ACTIVITIES
Actions or proposed actions that have an impact on stormwater runoff as specified in §
26-104 of this chapter.
RETENTION BASIN
An impoundment in which stormwater is stored and not released
during the storm event. Stored water may be released from the basin
at some time after the end of the storm.
RETURN PERIOD
The average interval, in years, within which a storm event
of a given magnitude can be expected to recur. For example, the twenty-five-year
return period rainfall has a four-percent probability of occurring
in any given year.
RUNOFF
Any part of precipitation that flows over the land surface.
SAFE PASSAGE
The routing of peak runoff events, usually the one-hundred-year
design event, safely through a structure without failure of that structure.
SCOUR
Generally refers to the change in a channel configuration
provoked by sediment imbalance, due to natural or man-made causes,
between the supply and transport capacity of the channel.
SEDIMENT BASIN
A barrier, dam, retention or detention basin located and
designed to retain rock, sand, gravel, silt, or other material transported
by water.
SENSITIVE (WATER QUALITY) AREA
An area protected because development within that area could
potentially cause contamination of groundwater reservoirs. These sensitive
land areas are defined in Appendix B, Exhibit 1.
SHEET FLOW
Runoff that flows over the ground surface as a thin, even
layer, not concentrated in a channel.
SIGNIFICANT DRAINAGEWAY
Any drainageway, as defined in this chapter, that exhibits
recharge benefits as would be credited within this chapter.
SILVICULTURE ACTIVITIES
Planning and activities necessary for the management of forestland.
These include timber inventory and preparation of forest management
plans, silvicultural treatment, cutting budgets, logging road design
and construction, timber harvesting, site preparation and reforestation.
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 distinct breaking of
the ground surface and downward movement of soil into bedrock voids.
SPILLWAY
A depression in the embankment of a pond or basin which is
used to pass peak discharge greater than the maximum design storm
controlled by the pond.
STABILIZATION
The proper placing, grading and/or covering of soil, rock
or earth to ensure their resistance to erosion, sliding or other movement.
STATE WATER QUALITY REQUIREMENTS
The regulatory requirements to protect, maintain, reclaim,
and restore water quality under Title 25 of the Pennsylvania Code
and the Clean Streams Law.
STORM SEWER
A system of pipes and/or open channels that convey intercepted
runoff and stormwater from other sources, but excludes domestic sewage
and industrial wastes.
STORMWATER
Drainage runoff from the surface of the land resulting from
precipitation or snow or ice melt.
STORMWATER MANAGEMENT FACILITY
Any structure, natural or man-made, that, due to its condition,
design, or construction, conveys, stores, or otherwise affects stormwater
runoff. Typical stormwater management facilities include, but are
not limited to, stormwater basins, open channels, storm sewers, pipes,
and infiltration structures.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff in the Spring Creek
Watershed adopted by the Centre County Commissioners as required by
the Act of October 4, 1978, P.L. 864, (Act 167), and known as the
"Spring Creek Watershed Action 167 Stormwater Management Plan."
STORMWATER MANAGEMENT SITE PLAN
The 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 may be designated as SWM site plan throughout this chapter. The contents of the SWM site plan are established in §
26-403.
STRATA
Tabular or sheet-like mass, distinct layers of homogenous
or gradational sedimentary material (consolidated rock or unconsolidated
earth) of any thickness, visually separable from other layers above
and below by a discrete change in the character of the material deposited
or by a sharp physical break deposition or both.
STRATIGRAPHIC UNIT
A stratum or body of strata recognized as a unit in the classification
of the rocks of the earth's crust with respect to any specific
rock character, property, attribute or for any purpose such as description,
mapping, and correlation.
STRUCTURAL FILL
Any soil mass that is compacted in lifts to some tested criteria
(standard or modified proctor) such as those under foundations or
adjacent to retaining walls. Areas that for several years after construction
respond to precipitation events similar to impervious areas.
SUBAREA
The smallest drainage unit of a watershed for which stormwater
management criteria have been established in the stormwater management
plan.
SWALE
A natural low-lying stretch of land or minor man-made conveyance
channel, which gathers or 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. The natural or physical surface features
of a region, considered collectively as to its form.
TOWNSHIP
The Township of Ferguson, Centre County, Pennsylvania.
TOWNSHIP ENGINEER
A professional engineer licensed in the Commonwealth of Pennsylvania
and duly appointed by the subject Township as its representative.
In the event that a stormwater utility is formed, all references to
the Township Engineer shall be considered to also imply the Stormwater
Utility Engineer.
UNDETAINED AREA
An area of a site that cannot be routed to a stormwater management
facility because of its location. Generally small areas around access
drives or below stormwater management facilities.
WATER QUALITY DEPTH
Depth of precipitation required to be used in computing the
water quality volume based on the percentage of imperviousness of
a site.
WATER QUALITY SENSITIVE (WQS) DEVELOPMENT
Land development projects that have a high potential to cause catastrophic loss to local water quality and could potentially threaten groundwater reservoirs. See §
26-302 for additional definition.
WATER TABLE
Upper surface of a layer of saturated material in the soil.
WATERS OF THIS COMMONWEALTH
Any and all rivers, streams, creeks, rivulets, ditches, watercourses,
storm sewers, lakes, dammed water, wetlands, ponds, springs, and all
other bodies or channels of conveyance of surface and underground
water, or parts thereof, whether natural or artificial, within or
on the boundaries of this commonwealth.
WATERSHED
The entire region or area drained by a river or other body
of water, whether natural or artificial, a drainage basin or sub-basin.
WETLAND
Those areas that are inundated or saturated by surface or
groundwater at a frequency and duration sufficient to support, and
that under normal circumstances do support, a prevalence of vegetation
typically adapted for life in saturated soil conditions, including
swamps, marshes, bogs, ferns, and similar areas.