[Ord. 763, passed 9-10-2012]
For the purposes of this chapter, certain terms and words used
herein shall be interpreted as follows.
(A)
Words used in the present tense include the future tense; the
singular number includes the plural, and the plural number includes
the singular; words of masculine gender include feminine gender; and
words of feminine gender include masculine gender.
(B)
The word "includes" or "including" shall not limit the term
to the specific example, but is intended to extend its meaning to
all other instances of like kind and character.
(C)
The word "person" includes an individual, firm, association,
organization, partnership, trust, company, corporation, unit of government
or any other similar entity.
(D)
The words "shall" and "must" are mandatory; the words "may"
and "should" are permissive.
(E)
The words "used" or "occupied" include the words "intended,
designed, maintained or arranged to be used, occupied or maintained."
[Ord. 763, passed 9-10-2012]
For the purpose of this chapter, the following definitions shall
apply unless the context clearly indicates or requires a different
meaning.
The removal of the surface of the land through the combined
action of humans' activity and the natural processes of a rate
greater than would occur because of the natural processes alone.
The work of producing crops and raising livestock including
tillage, plowing, disking, harrowing, pasturing, nursery and sod operations,
excluding greenhouse structures, and installation of conservation
measures. Construction of new buildings or impervious area is not
considered an "agricultural activity."
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.
A landowner or other person who has filed an application
to the municipality for approval to engage in any regulated activity
defined in § 1230.105 of this chapter.
Engineering or site drawings maintained by the contractor
as he or she constructs the project and upon which he or she documents
the actual locations of the building components and changes to the
original contract documents. These documents, or a copy of same, are
turned over to the Municipal Engineer at the completion of the project.
The channel at the top-of-bank or point from where water
begins to overflow onto a flood plain.
Portion of stream discharge derived from groundwater; the
sustained discharge that does not result from direct runoff or from
water diversions, reservoir releases, piped discharges or other human
activities.
A stormwater retention area that utilizes woody and herbaceous
plants and soils to remove pollutants before infiltration occurs.
Activities, facilities, designs, measures or procedures used
to manage stormwater impacts from regulated activities, to meet state
water quality requirements, to promote infiltration, 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.
See "riparian buffer."
An open drainage feature through which stormwater flows.
CHANNELS include, but shall not be limited to, natural and human-made
drainageways, swales, streams, ditches, canals and pipes flowing partly
full.
The widening, deepening or headward cutting of channels and
waterways caused by stormwater runoff or bankfull flows.
An underground reservoir or tank for storing rainwater.
The Delaware County Conservation District.
A facility or structure used for the transportation or transmission
of something from one place to another.
A structure with its appurtenant works, which carries water
under or through an embankment or fill.
A human-made barrier, together with its appurtenant works
constructed for the purpose of impounding or storing water or another
fluid or semi-fluid. A DAM may include a refuse bank, fill or structure
for highway, railroad or other purposes which impounds or may impound
water or another fluid or semi-fluid.
The Pennsylvania Department of Environmental Protection.
A state registered professional engineer, registered landscape
architect, registered professional land surveyor trained to develop
SWM site plan, or any person licensed by the Pennsylvania Department
of State or qualified by law to perform the work required by the chapter.
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.
The agent of the Delaware County Planning Department, Delaware
County Conservation District and/or agent of the governing body involved
with the administration, review or enforcement of any provisions of
this chapter by contract or memorandum of understanding.
An impoundment designed to collect and retard stormwater
runoff by temporarily storing the runoff and releasing it at a predetermined
rate. "Detention basins" are designed to drain completely soon after
a rainfall event and become dry until the next rainfall event.
The prevention of, or to prevent, the discharge, directly
or indirectly, of a given volume of stormwater runoff into surface
waters by temporary storage.
A person who seeks to undertake any regulated earth disturbance
activities at a project site in the municipality.
The specific tract or parcel of land where any regulated
activity set forth in § 1230.105 is planned, conducted or
maintained.
Any human-induced change to improved or unimproved real estate,
whether public or private, including, but not limited to, land development,
construction, installation or expansion of a building or other structure,
land division, street construction, drilling and site alteration such
as embankments, dredging, grubbing, grading, paving, parking or storage
facilities, excavation, filling, stockpiling or clearing. As used
in this chapter, development encompasses both new development and
redevelopment.
The outside bark diameter at breast height which is defined
as 4 1/2 feet (1.37 m) above the forest floor on the uphill side
of the tree.
Drainage discharge that is not confined to a single point
location or channel, including sheet flow or shallow concentrated
flow.
The point of discharge for a stormwater facility.
Unstabilized land area where an earth disturbance activity
is occurring or has occurred.
A human-made waterway constructed for irrigation or stormwater
conveyance purposes.
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 project site would be directed towards it by gravity.
A stormwater management facility designed to transport stormwater
runoff that includes channels, swales, pipes, conduits, culverts and
storm sewers.
A right granted by a landowner to a grantee allowing the
use of private land for stormwater management purposes.
A permit issued by the municipality after the stormwater
management site plan has been approved.
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;
the moving, depositing, stockpiling or storing of soil, rock or earth
materials.
A conveyance area that is used to pass peak discharge greater
than the maximum design storm controlled by the stormwater facility.
A structure or activity that changes, expands or diminishes
the course, current or cross-section of a watercourse, floodway or
body of water.
The process by which the surface of the land, including water/stream
channels, is worn away by water, wind or chemical action.
A plan that is designed to minimize accelerated erosion and
sedimentation. Said plan must be submitted to and approved by the
appropriate Conservation District before construction can begin.
Surface waters of high quality which satisfy Pennsylvania
Code Title 25 Environmental Protection, Chapter 93, Water Quality
Standards, § 93.4b(b) (25 Pa. Code Ch. 93, § 93.4b(b))
(relating to anti-degradation).
The initial condition of a project site prior to the proposed
alteration. If the initial condition of the site is undeveloped land,
the land use shall be considered as "meadow" unless the natural land
cover is proven to generate a lower curve number or Rational "c" value,
such as forested lands.
Federal Emergency Management Agency.
A situation where the greatest possible profit cannot be
fully realized from development/redevelopment on a given parcel of
land due to added costs or burdens associated with the design, construction
and/or maintenance of stormwater structures, facilities, buffers and/or
setbacks.
A temporary condition of partial or complete inundation of
land areas from the overflow of streams, rivers and other waters of
this Commonwealth.
Any land area susceptible to inundation by water from any
natural source or as delineated by the applicable Department of Housing
and Urban Development, Federal Insurance Administration flood hazard
boundary map as being a special flood hazard area.
The channel of a watercourse and those portions of the adjoining
flood plains which are reasonably required to carry and discharge
the 100-year frequency flood. Unless otherwise specified, the boundary
of the "floodway" is as indicated on maps and flood insurance studies
provided by FEMA. In an area where no FEMA maps or studies have defined
the boundary of the 100-year frequency "floodway," it is assumed,
absent evidence to the contrary, that the "floodway" extends from
the stream to 50 feet from the top-of-bank.
The study of landforms associated with river channels and
the processes that form them.
Planning and associated activities necessary for the management
of forest lands. These include timber inventory and preparation of
forest management plans, silvicultural treatment, cutting budgets,
logging road design and construction, timber harvesting and reforestation.
A vertical distance between the elevation of the design high-water
and the top of a dam, levee, tank, basin, swale or diversion berm.
The space is required as a safety margin in a pond or basin.
A natural or human-made waterway, usually broad and shallow,
covered with erosion-resistant grasses used to convey surface water.
Water beneath the earth's surface that supplies wells
and springs and is often between saturated soil and rock.
The replenishment of existing natural underground water supplies
from rain or overland flow.
The United States Army Corps of Engineers, Hydrologic Engineering
Center (HEC) - Hydrologic Modeling System (HMS). This model was used
to model the Darby-Cobbs and Crum Creek watersheds during the Act
167 plan development and was the basis for the standards and criteria
of this chapter.
Surface waters having quality which exceeds levels necessary
to support propagation of fish, shellfish and wildlife and recreation
in and on the water by satisfying Pennsylvania Code Title 25 Environmental
Protection, Chapter 93, Water Quality Standards, § 93.4b(a)
(25 Pa. Code Ch. 93, § 93.4b(a)).
Areas where land use or activities generate highly contaminated
runoff with concentrations of pollutants in excess of those typically
found in stormwater.
A graph representing the discharge of water versus time for
a selected point in the drainage system.
The hydrologic cycle or balance that sustains quality and
quantity of stormwater, baseflow, storage and groundwater supplies
under natural conditions.
A classification of soils by the Natural Resources Conservation
Service (NRCS), formerly the Soil Conservation Service (SCS), into
four runoff potential groups. The groups range from A soils, which
are very permeable and produce little runoff, to D soils, which are
not very permeable and produce much more runoff.
A surface that prevents the infiltration of water into the
ground. "Impervious surfaces" include, but are not limited to, streets,
sidewalks, pavements, driveway areas or roofs. Any surface areas designed
to be gravel or crushed stone shall be regarded as "impervious surfaces."
A retention or detention basin designed to retain stormwater
runoff and release it at a controlled rate.
Development that occurs on smaller parcels that remain undeveloped
but are within or in very close proximity to urban or densely developed
areas. Infill development usually relies on existing infrastructure
and does not require an extension of water, sewer or other public
utilities.
Movement of surface water into the soil, where it is absorbed
by plant roots, evaporated into the atmosphere, or percolated downward
to recharge groundwater.
A structure designed to direct runoff into the underground
water (e.g., French drains, seepage pits or seepage trenches).
The flow entering the stormwater management facility and/or
BMP.
The upstream end of any structure through which water may
flow.
A stream that flows only part of the time. Flow generally
occurs for several weeks or months in response to seasonal precipitation
or groundwater discharge.
The lowest surface, the floor or bottom of a culvert, drain,
sewer, channel, basin, BMP or orifice.
Any of the following activities:
The improvement of one lot or two or more contiguous lots, tracts
or parcels of land for any purpose involving:
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; or
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.
A subdivision of land;
Development in accordance with the Pa. Mun. Plan. Code, 53 P.S.
§ 10503(1.1).
A soil horizon or condition in the soil profile or underlying
strata that includes one of the following:
A seasonal high water table, whether perched or regional, determined
by direct observation of the water table or indicated by soil mottling;
A rock with open joints, fracture or solution channels, or masses
of loose rock fragments, including gravel, with insufficient fine
soil to fill the voids between the fragments; or
A rock formation, other stratum or soil condition that is so
slowly permeable that it effectively limits downward passage of water.
A designated parcel, tract or area of land established by
a plat or otherwise as permitted by law and to be used, developed
or built upon as a unit.
Any stream segment or other runoff conveyance used as a reach
in watershed-specific hydrologic models.
A method for calculation of velocity of flow (e.g., feet
per second) and flow rate (e.g., cubic feet per second) in open channels
based upon channel shape, roughness, depth of flow and slope. Open
channels may include closed conduits so long as the flow is not under
pressure.
The maximum (largest) design storm that is controlled by
the stormwater facility.
A professional engineer licensed as such in the Commonwealth,
duly appointed as the Engineer for a municipality, planning agency
or joint planning commission.
Brookhaven Borough, Delaware County, Pennsylvania.
Pre-development condition.
See HYDROLOGIC REGIME.
Undisturbed surface area or depression where stormwater collects
and a portion of which infiltrates and replenishes the underground
and groundwater.
Pollution that enters a waterbody from diffuse origins in
the watershed and does not result from discernible, confined or discrete
conveyances.
Water flowing in stormwater collection facilities, such as
pipes or swales, which is not the result of a rainfall event or snowmelt.
Methods of controlling stormwater runoff quantity and quality,
such as innovative site planning, impervious area and grading reduction,
protection of natural depression areas, temporary ponding on site
and other techniques.
National Pollutant Discharge Elimination System, the federal
government's system for issuance of permits under the Clean Water
Act, which is delegated to PADEP in Pennsylvania.
Natural Resource Conservation Service (previously SCS).
A conveyance channel that is not enclosed.
Point source as described in 40 C.F.R. § 122.2
at the point where the municipality's storm sewer system discharges
to surface waters of the Commonwealth.
The flow exiting the stormwater management facility and/or
BMP.
Points of water disposal to a stream, river, lake, tidewater
or artificial drain.
The parcel of land from which a land development or subdivision
originates, determined from the date of municipal adoption of this
chapter.
Involves the use of parking areas as temporary impoundments
with controlled release rates during rainstorms.
The maximum rate of stormwater runoff from a specific storm
event.
The Best Management Practices Manual published by the Pennsylvania
Department of Environmental Protection. The manual is to supplement
federal and state regulations and the Department of Environmental
Protection's Comprehensive Stormwater Management Policy that
emphasizes effective site planning as the preferred method of managing
runoff while also providing numerous examples of BMPs that can be
employed in the state to further avoid and minimize flooding and water
resource problems.
Any area not defined as impervious.
A culvert, closed conduit or similar structure (including
appurtenances) that conveys stormwater.
The Planning Commission of Brookhaven Borough.
Any 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, as defined in state regulations
at 25 Pa. Code § 92.1.
Period after construction during which disturbed areas are
stabilized, stormwater controls are in place and functioning, and
all proposed improvements in the approved land development plan are
completed.
Prior to commencing construction activities.
Undeveloped/natural condition.
Techniques employed in stormwater BMPs to provide storage
or filtering to trap coarse materials and other pollutants before
they enter the system, but not necessarily designed to meet the water
quality volume requirements of § 1230.306.
The specific area of land where any regulated activities
in the municipality are planned, conducted or maintained.
See "design professional (qualified)."
A rainfall-runoff relation used to estimate peak flow.
Any stream segment or other runoff conveyance used in the
watershed-specific hydrologic models.
The replenishment of groundwater through the infiltration
of rainfall, other surface waters or land application of water or
treated wastewater.
Demolition and subsequent rebuilding of impervious surface.
Original documents revised to suit the as-built conditions
and subsequently provided by the Engineer to the client. The Engineer
reviews the contractor's asbuilts against his or her own records
for completeness, then either turns these over to the client or transfers
the information to a set of reproducibles, in both cases for the client's
permanent records.
Any development that requires demolition or removal of existing
structures or impervious surfaces at a site and replacement with new
impervious surfaces. Maintenance activities such as top-layer grinding
and repaving are not considered to be "redevelopment." Interior remodeling
projects and tenant improvements are also not considered to be "redevelopment."
Any earth disturbances activities or any activities that
involve the alteration or development of land in a manner that may
affect stormwater runoff, including redevelopment.
Activity involving earth disturbance subject to regulation
under 25 Pa. Code Ch. 92, Ch. 102 or the Clean Streams Law.
The percentage of existing conditions peak rate of runoff
from a site or subarea to which the proposed conditions peak rate
of runoff must be reduced to protect downstream areas.
Resurfacing of the impervious surface that does not involve
reconstruction of an existing paved (impervious) surface.
Reconstruction of and full replacement of an existing paved
(impervious) surface.
A structure in which stormwater is stored and not released
during the storm event. RETENTION BASINS are designed for infiltration
purposes and do not have an outlet.
The prevention of direct discharge of stormwater runoff into
receiving waters or water bodies by temporary or permanent containment
in a pond or depression; examples include systems which discharge
by percolation to groundwater, and/or evaporation processes and which
generally have residence times of less than three days.
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 would be expected to recur on the average of
once every 25 years.
Pertaining to anything connected with or immediately adjacent
to the banks of a stream or other body of water.
An area of land adjacent to a body of water and managed to
maintain the integrity of stream channels and shorelines to:
A vertical pipe extending from the bottom of a pond that
is used to control the discharge rate from the pond for a specified
design storm.
Earth disturbance activities within the existing road cross-section,
such as grading and repairing existing unpaved road surfaces, cutting
road banks, cleaning or clearing drainage ditches, and other similar
activities.
A drainage conduit or pipe that collects water runoff from
a roof and leads it away from the structure.
The temporary ponding and gradual release of stormwater falling
directly onto flat roof surfaces using controlled-flow roof drains
in building designs.
Any part of precipitation that flows over the land surface.
Subdivision and land development ordinance.
Soil or other materials transported by surface water as a
product of erosion.
A barrier, dam or retention or detention basin located and
designed in such a way as to retain rock, sand, gravel, silt or other
material transported by water during construction.
The placement, discharge or any other introduction of sediment
into the waters of the Commonwealth.
The process by which mineral or organic matter is accumulated
or deposited by the movement of water or air.
An area of excavated earth filled with loose stone or similar
coarse material into which surface water is directed for infiltration
into the underground water.
A conveyance or system of conveyances (including roads with
drainage systems, municipal streets, catch basins, curbs, gutters,
ditches, human-made channels or storm drains) primarily used for collecting
and conveying stormwater runoff.
Stormwater runoff flowing in shallow, defined ruts prior
to entering a defined channel or waterway.
A flow process associated with broad, shallow water movement
on sloping ground surfaces that is not channelized or concentrated.
A method of runoff computation developed by NRCS that is
based on relating soil type and land use/cover to a runoff parameter
called curve number (CN).
The zone through which contaminants, if present, are likely
to migrate and reach a drinking water well or surface water intake.
Watersheds that have been designated by PADEP as EV or HQ
waters.
A conveyance that is used to pass the peak discharge of the
maximum design storm that is controlled by the stormwater facility.
The regulatory requirements to protect, maintain, reclaim
and restore water quality under Pa. Code Title 25 and the Clean Streams
Law.
A reservoir routing procedure based on solution of the continuity
equation (inflow minus outflow equals the change in storage) with
outflow defined as a function of storage volume and depth.
The number of times that a given storm "event" occurs or
is exceeded on the average in a stated period of years (see "return
period").
A system of pipes and/or open channels that conveys intercepted
runoff and stormwater from other sources but excludes domestic sewage
and industrial wastes.
Drainage runoff from the surface of the land resulting from
precipitation, snow or ice melt.
The plan prepared by the applicant or his or her representative
indicating how stormwater runoff will be managed at the particular
site of interest according to this chapter, and including all necessary
design drawings, calculations, supporting text and documentation to
demonstrate that chapter requirements have been met, hereafter referred
to as "SWM site plan."
Those subareas of a watershed in which some type of detention
is required to meet the plan requirements and the goals of Act 167.
Any structure, natural or human-made, that, due to its condition,
design or construction, conveys, stores or otherwise affects stormwater
runoff quality, rate or quantity. Typical "stormwater management facilities"
include, but are not limited to, detention and retention basins, open
channels, storm sewers, pipes and infiltration structures.
The watershed plan for managing stormwater runoff for a watershed,
adopted by Delaware and Chester Counties as required by the Act of
October 4, 1978, Pub. L. 864 (Act 167), as amended, and known as the
"Stormwater Management Act." See also "watershed stormwater management
plan."
A natural watercourse.
The land area adjacent to each side of a stream essential
to maintaining water quality (see also "riparian buffer").
A bridge, culvert or other structure in excess of 100 feet
in length upstream to downstream which encloses a regulated water
of the Commonwealth.
The smallest drainage unit of a watershed for which stormwater
management criteria have been established in the stormwater management
plan.
The 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.
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 waters, or parts
thereof, whether natural or artificial, within or on the boundaries
of the Commonwealth.
A low-lying stretch of land that gathers or carries surface
water runoff.
See "stormwater management site plan."
See "forest management."
The time required for surface runoff to travel from the hydraulically
most distant point of the watershed to a point of interest within
the watershed. This time is the combined total of overland flow time
and flow time in pipes or channels, if any.
Highest point of elevation in a stream channel cross-section
at which a rising water level just begins to flow out of the channel
and over the flood plain.
Natural condition (see also "pre-development condition").
United States Department of Agriculture.
Seasonal depressional wetlands that are covered by shallow
water for variable periods from winter to spring but may be completely
dry for most of the summer and fall.
A channel or conveyance of surface water having a defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
Any and all rivers, streams, creeks, rivulets, impoundments,
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 the Commonwealth.
Region or area drained by a river, watercourse or other body
of water, whether natural or artificial.
A watershed plan for managing stormwater runoff for a watershed,
adopted by Delaware and Chester Counties as required by the Act of
October 4, 1978, P.L. 864 (Act 167), as amended, and known as the
"Stormwater Management Act" (e.g., Chester Creek, Ridley Creek, Crum
Creek, Darby-Cobbs Creeks). See also "stormwater management plan."
The surface and subsurface area surrounding a water-supply
well, well field or spring supplying a public water system through
which contaminants are reasonably likely to move toward and reach
the water source.
Pond for urban runoff management that is designed to detain
urban runoff and always contains water.
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. WETLANDS
generally include swamps, marshes, bogs, fens and similar areas.
A natural groundcover with more than one viable tree of a
DBH of six inches or greater per 1,500 square feet which existed within
three years of application; a cover condition for which SCS curve
numbers have been assigned or to which equivalent Rational Method
runoff coefficients have been assigned.
