[Adopted by the City Council of the City of Harrisburg 5-14-2013 by Ord. No.
6-2013.[1] Amendments noted where applicable.]
CROSS-REFERENCES
Stormwater Management Act: see 32 P.S. § 680.1 et seq.
The governing body of the City of Harrisburg finds that:
A.
Inadequate management of accelerated stormwater runoff resulting
from development throughout a watershed increases flood flows and
velocities, contributes to erosion and sedimentation, overtaxes the
carrying capacity of existing streams and storm sewers, greatly increases
the cost of public facilities to convey and manage stormwater, undermines
floodplain management and flood reduction efforts in upstream and
downstream communities, reduces groundwater recharge, threatens public
health and safety, and increases nonpoint source pollution of water
resources.
B.
A comprehensive program of stormwater management, including reasonable
regulation of development and activities causing accelerated erosion,
is fundamental to the public health, safety, welfare, and the protection
of the people of the City of Harrisburg and all the people of the
commonwealth, their resources, and the environment.
C.
Inadequate planning and management of stormwater runoff resulting
from land development and redevelopment throughout a watershed can
also harm surface water resources by changing the natural hydrologic
patterns; accelerating stream flows (which increase scour and erosion
of streambeds and stream banks thereby elevating sedimentation); destroying
aquatic habitat; and elevating aquatic pollutant concentrations and
loadings such as sediments, nutrients, heavy metals, and pathogens.
Groundwater resources are also impacted through loss of recharge.
D.
Stormwater can be an important water resource by providing groundwater
recharge for water supplies and base flow of streams, which also protects
and maintains water quality.
E.
Public education on the control of pollution from stormwater is an
essential component in successfully addressing stormwater issues.
F.
Federal and state regulations require certain municipalities to implement
a program of stormwater controls. These municipalities are required
to obtain a permit for stormwater discharges from their separate storm
sewer systems under the National Pollutant Discharge Elimination System
(NPDES).
G.
Nonstormwater discharges to the municipal separate storm sewer system
can contribute to pollution of waters of the commonwealth.
The purpose of this Part 9 is to promote health, safety, and welfare within the City of Harriburg, Dauphin County, by minimizing the harms and maximizing the benefits described in § 9-901.2 of this Part 9 through provisions intended to:
A.
Meet legal water quality requirements under state law, including
regulations at 25 Pa. Code Chapter 93 to protect, maintain, reclaim,
and restore the existing and designated uses of the waters of the
commonwealth.
B.
Manage accelerated runoff and erosion and sedimentation problems
close to their source by regulating activities that cause these problems.
C.
Preserve the natural drainage systems to the maximum extent practicable.
D.
Maintain groundwater recharge, to prevent degradation of surface
and groundwater quality, and to otherwise protect water resources.
E.
Maintain existing flows and quality of streams and watercourses.
F.
Preserve and restore the flood-carrying capacity of streams and prevent
scour and erosion of stream banks and streambeds.
G.
Manage stormwater impacts close to the runoff source, with a minimum
of structures and a maximum use of natural processes.
H.
Provide procedures, performance standards, and design criteria for
stormwater planning and management.
I.
Provide proper operations and maintenance of all temporary and permanent
stormwater management facilities and best management practices (BMPs)
that are constructed and implemented.
J.
Provide standards to meet the NPDES permit requirements.
K.
Implement an illegal discharge detection and elimination program
within the MS4 permitted urbanized areas to address nonstormwater
discharges into the City of Harrisburg's separate storm sewer
system.
A.
Primary authority. The City of Harrisburg is empowered to regulate
land use activities that affect runoff by the authority of the Act
of October 4, 1978, P.L. 864 (Act 167), 32 P.S. § 680.1
et seq., as amended (the Stormwater Management Act); and the Third
Class City Code, Act 317 of 1931, P.L. 932, 53 P.S. § 35101
et seq., as amended.
B.
Secondary authority. The City of Harrisburg also is empowered to
regulate land use activities that affect runoff by the authority of
the Act of July 31, 1968, P.L. 805, No. 247 (the Pennsylvania Municipalities
Planning Code), as amended.
A.
This Part 9 shall apply to all areas of the City of Harrisburg, any
regulated activity within the City of Harrisburg, and all stormwater
runoff entering into the City of Harrisburg's municipal separate
storm sewer system from lands within the boundaries of the City of
Harrisburg.
B.
Earth disturbance activities and associated stormwater management
controls are also regulated under existing state law and implementing
regulations. This Part 9 shall operate in coordination with those
parallel requirements; the requirements of this Part 9 shall be no
less restrictive in meeting the purposes of this Part 9 than state
law.
C.
"Regulated activities" are any earth disturbance activities or any
activities that involve the alteration or development of land in a
manner that may affect stormwater runoff. Regulated activities include,
but are not limited to, the following listed items:
(1)
Earth disturbance activities.
(2)
Land development.
(3)
Subdivision.
(4)
Construction of new or additional impervious or semipervious
surfaces.
(5)
Construction of new buildings or additions to existing buildings.
(6)
Diversion or piping of any natural or man-made stream channel.
(7)
Installation of stormwater management facilities or appurtenances
thereto.
(8)
Installation of stormwater BMPs.
Approvals issued and actions taken pursuant to this Part 9 do
not relieve the applicant of the responsibility to comply with or
to secure required permits or approvals for activities regulated by
any other applicable codes, laws, rules, statutes, or ordinances.
To the extent that this Part 9 imposes more rigorous or stringent
requirements for stormwater management, the specific requirements
contained in this Part 9 shall be followed.
Notwithstanding any provision(s) of this Part 9, including exemptions,
any landowner or any person engaged in the alteration or development
of land which may affect stormwater runoff characteristics shall implement
such measures as are reasonably necessary to prevent injury to health,
safety, or other property. Such measures also shall include actions
as are required to manage the rate, volume, direction, and quality
of resulting stormwater runoff in a manner which otherwise adequately
protects health, property, and water quality.
The degree of stormwater management sought by the provisions
of this Part 9 is considered reasonable for regulatory purposes. This
Part 9 shall not create liability on the part of the City of Harrisburg,
any appointed or elected official of the City of Harrisburg, the Dauphin
County Conservation District or any officer, engineer, or employee
thereof for any erosion, sedimentation or flood damages that result
from reliance on this Part 9 or any administrative decision lawfully
made thereunder.
A.
For the purposes of this Part 9, certain terms and words used herein
shall be interpreted as follows:
(1)
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.
(2)
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.
(3)
The word "person" includes an individual, firm, association,
organization, partnership, trust, company, corporation, or any other
similar entity.
(4)
The words "shall" and "must" are mandatory; the words "may"
and "should" are permissive.
(5)
The words "used or occupied" include the words "intended, designed,
maintained, or arranged to be used, occupied or maintained."
B.
ACCELERATED EROSION
AGRICULTURAL ACTIVITIES
ALTERATION
APPLICANT
APPROVING AGENCY
BEST MANAGEMENT PRACTICES (BMPs)
BMP MANUAL
CHANNEL EROSION
CISTERN
CITY
COMBINED SEWER
CONSERVATION DISTRICT
CULVERT
DAM
DESIGNEE
DESIGN STORM
DETENTION BASIN
DETENTION VOLUME
DEVELOPER
DEVELOPMENT SITE (SITE)
DISTURBED AREA
DOWNSLOPE PROPERTY LINE
DRAINAGE CONVEYANCE FACILITY
DRAINAGE EASEMENT
DRAINAGEWAY
EARTH DISTURBANCE ACTIVITY
EROSION
EROSION AND SEDIMENT POLLUTION CONTROL PLAN
EXCEPTIONAL VALUE WATERS
EXISTING CONDITION
FEMA
FLOOD
FLOOD FRINGE
FLOODPLAIN
FLOODWAY
FOREST MANAGEMENT/TIMBER OPERATIONS
FREEBOARD
GRADE
GROUNDWATER RECHARGE
HEC-HMS MODEL CALIBRATED
HIGH-QUALITY WATERS
HYDROLOGIC SOIL GROUP (HSG)
IMPERVIOUS SURFACE (IMPERVIOUS AREA)
INFILTRATION STRUCTURES
INLET
KARST
LAND DEVELOPMENT (DEVELOPMENT)
LIMIT OF DISTURBANCE
MAIN STEM (MAIN CHANNEL)
MANNING EQUATION (MANNING FORMULA)
MUNICIPAL SEPARATE STORM SEWER
(1)
(2)
(3)
(4)
MUNICIPAL SEPARATE STORM SEWER SYSTEM (MS4)
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)
NOAA ATLAS 14
NONPOINT SOURCE POLLUTION
NRCS
OPEN CHANNEL
OUTFALL
OUTLET
PADEP
PARKING LOT STORAGE
PEAK DISCHARGE
PERSON
PERVIOUS AREA
PIPE
PLANNING COMMISSION
POINT SOURCE
PROBABLE MAXIMUM FLOOD (PMF)
PROJECT SITE
QUALIFIED PROFESSIONAL
RATIONAL FORMULA
REDEVELOPMENT
REGULATED ACTIVITY
REGULATED EARTH DISTURBANCE ACTIVITY
RELEASE RATE
RELEASE RATE DISTRICT
RETENTION VOLUME/REMOVED RUNOFF
RETURN PERIOD
RIPARIAN BUFFER
RISER
ROAD MAINTENANCE
ROOFTOP DETENTION
RUNOFF
RUNOFF CAPTURE VOLUME
SEDIMENT
SEDIMENTATION
SEDIMENT BASIN
SEDIMENT POLLUTION
SEEPAGE PIT/SEEPAGE TRENCH
SHEET FLOW
SOIL-COVER COMPLEX METHOD
SPILLWAY
STATE WATER QUALITY REQUIREMENTS
(1)
(2)
(3)
(4)
STORAGE INDICATION METHOD
STORM FREQUENCY
STORMWATER
STORMWATER HOTSPOT
STORMWATER MANAGEMENT FACILITIES
STORMWATER MANAGEMENT PLAN
STORMWATER MANAGEMENT SITE PLAN (SWM SITE PLAN)
STREAM ENCLOSURE
SUBDIVISION
SUBWATERSHED AREA
SWALE
TIMBER OPERATIONS
TIME OF CONCENTRATION (Tc)
TO GRADE
USDA
WATERCOURSE
WATERSHED
WATERS OF THE COMMONWEALTH
WETLAND
As used in this Part 9, the following terms shall have the meanings
indicated:
The removal of the surface of the land through the combined
action of human activity and the natural processes at a rate greater
than would occur because of the natural process alone.
Activities associated with agriculture such as agricultural
cultivation, agricultural operation, and animal heavy use areas. This
includes the work of producing crops, tillage, land clearing, plowing,
disking, harrowing, planting, harvesting crops, or pasturing and raising
of livestock 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;
changing of surface conditions by causing the surface to be more or
less impervious; land disturbance.
A landowner, developer, or other person who has filed an
application for approval to engage in any regulated activities at
a project site within the City of Harrisburg.
The City of Harrisburg or its designated agent.
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 Part 9. Stormwater BMPs are commonly
grouped into one of two broad categories or measures: "nonstructural"
or "structural." Nonstructural BMPs are measures referred to as operational
and/or behavior-related practices that attempt to minimize the contact
of pollutants with stormwater runoff, whereas structural BMPs are
measures 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 wet 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.
The Pennsylvania Stormwater Best Management Practices Manual
as published by the Department of Environmental Protection, Bureau
of Watershed Management, document number 363-0300-002, effective date
December 30, 2006, and as revised.
The widening, deepening, and headward cutting of small channels
and waterways due to erosion caused by moderate to large floods.
An underground reservoir or tank for storing rainwater.
The City of Harrisburg, Dauphin County, Pennsylvania, or
its designee.
A system of pipes and inlets that convey both intercepted
runoff and stormwater and also include domestic sewage and industrial
waste flows.
The Dauphin County Conservation District (DCCD). The Dauphin
County Conservation District has the authority under a delegation
agreement executed with the Department of Environmental Protection
to administer and enforce all or a portion of the regulations promulgated
under 25 Pa. Code Chapter 102.
A structure with appurtenant works that carries a stream
and/or stormwater runoff under or through an embankment or fill.
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.
The agent of the City of Harrisburg involved with the administration,
review or enforcement of any provisions of this Part 9 by contract
or memorandum of understanding.
The magnitude and temporal distribution of precipitation
from a storm event measured in probability of occurrence (e.g., a
twenty-five-year storm) and duration (e.g., 24 hours), used in the
design and evaluation of stormwater management systems. Also see "return
period."
An impoundment structure designed to manage stormwater runoff
by temporarily storing the runoff and releasing it at a predetermined
rate.
The volume of runoff that is captured and released during
or after a storm event into waters of the commonwealth at a controlled
rate.
A person, partnership, association, corporation, or other
entity, or any responsible person therein or agent thereof, that undertakes
any regulated activity of this Part 9.
The specific tract of land for which a regulated activity
is proposed. Also see "project site."
An unstabilized land area where an earth disturbance activity
is occurring or has occurred.
That portion of the property line of the lot, tract, or parcels
of land being developed located such that all overland or pipe flow
from the site would be directed towards it.
A stormwater management facility designed to transmit stormwater
runoff and shall include streams, channels, swales, pipes, conduits,
culverts, storm sewers, etc.
A right granted by a landowner to a grantee, allowing the
use of private land for stormwater management, drainage, or conveyance
purposes.
Any natural or artificial watercourse, trench, ditch, pipe,
swale, channel, or similar depression into which surface water flows.
A construction or other human activity which disturbs the
surface of the land, including, but not limited to, clearing and grubbing,
grading, excavations, embankments, land development, agricultural
plowing or tilling, timber harvesting activities, road maintenance
activities, mineral extraction, and the moving, depositing, stockpiling,
or storing of soil, rock or earth materials.
The movement of soil particles by the action of water, wind,
ice or other natural forces.
A plan which is designed to minimize accelerated erosion
and sedimentation.
Surface waters of high quality, which satisfies Pennsylvania
Code Title 25, Environmental Protection, Chapter 93, Water Quality
Standards, § 93.4b(b) (relating to antidegradation).
The initial condition of a project site prior to the proposed
construction. 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 lower curve numbers or Rational "C"
value, such as forested lands.
The Federal Emergency Management Agency.
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 the commonwealth.
The remaining portions of the one-hundred-year floodplain
outside of the floodway boundary.
Any land area susceptible to inundation by water from any
natural source or delineated by applicable Department of Housing and
Urban Development, Federal Insurance Administration Flood Hazard Boundary
Map as being a special flood hazard area. Included are lands adjoining
a river or stream that have been or may be inundated by a one-hundred-year
flood. Also included are areas that comprise Group 13 soils, as listed
in Appendix A of the Pennsylvania Department of Environmental Protection
(PADEP) Technical Manual for Sewage Enforcement Officers (as amended
or replaced from time to time by PADEP).
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.
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.
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.
A slope, usually of a road, channel or natural ground, specified
in percent and shown on plans as specified herein.
Replenishment of existing natural underground water supplies.
The Hydrologic Engineering Center-Hydrologic Modeling System,
a computer-based hydrologic model technique adapted to the Spring
Creek and Paxton Creek Watershed for the Act 167 Plan. The model has
been calibrated by adjusting key model input parameters.
Surface water 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).
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 Natural Resources Conservation Service (NRCS) of the
United States Department of Agriculture 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 interest may be identified
from a soil survey report, which can be obtained from the local NRCS
office or the Dauphin County Conservation District office.
A surface that prevents the infiltration of water into the
ground. Impervious surfaces (or areas) shall include but are not limited
to roofs, additional indoor living spaces, patios, garages, storage
sheds and similar structures, and any new streets and sidewalks. Decks,
parking areas, and driveway areas are not counted as impervious areas
if they do not prevent infiltration. Any surface area proposed to
initially be gravel or crushed stone shall be assumed to be impervious,
unless designed as an infiltration BMP.
A structure designed to direct runoff into the ground (e.g.,
french drains, seepage pits, seepage trench, etc.).
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.
A type of topography or landscape characterized by depressions,
sinkholes, limestone towers and steep-sided hills, underground drainage,
and caves. Karst is formed on carbonate rocks, such as limestone or
dolomite and sometimes gypsum.
A line provided on the SWM site plan that indicates the total
area to be disturbed during a proposed earth disturbance activity.
Any stream segment or other runoff conveyance facility used
as a reach in the Dauphin County Act 167 watershed hydrologic model(s).
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.
A conveyance or system of conveyances (including roads with
drainage systems, municipal streets, catch basins, curbs, gutters,
ditches, man-made channels, or storm drains), which is all of the
following:
Owned or operated by a state, city, town, borough, township,
county, district, association or other public body (created under
state law) having jurisdiction over disposal of sewage, industrial
wastes, stormwater or other wastes;
Designed or used for collecting or conveying stormwater;
Not a combined sewer; and
Not part of a publicly owned treatment works as defined at 40
CFR § 122.2.
All separate storm sewers that are defined as "large" or
"medium" or "small" municipal separate storm sewer systems pursuant
to 40 CFR § 122.26(b)(18), or designated as regulated under
40 CFR § 122.26(a)(1)(v).
The federal government's system for issuance of permits
under the Clean Water Act, which is delegated to PADEP in Pennsylvania.
Precipitation-Frequency Atlas of the United States, Atlas
14, Volume 2, United States Department of Commerce, National Oceanic
and Atmospheric Administration, National Weather Service, Hydrometeorological
Design Studies Center, Silver Spring, Maryland (2004). NOAA's
Atlas 14 can be accessed at Internet address: http://hdsc.nws.noaa.gov/hdsc/pfds/.
Pollution that enters a water body from diffuse origins in
the watershed and does not result from discernible, confined, or discrete
conveyances.
The Natural Resource Conservation Service [previously the
Soil Conservation Service(SCS)].
A drainage element in which stormwater flows with an open
surface. Open channels include, but shall not be limited to, natural
and man-made drainageways, swales, streams, ditches, canals, and pipes
not under pressure.
The point of water disposal from a stream, river, lake, tidewater,
or artificial drain.
The Pennsylvania Department of Environmental Protection.
Involves the use of impervious parking areas as temporary
impoundments with controlled release rates during rainstorms.
The maximum rate of stormwater runoff from a specific storm
event.
An individual, partnership, public or private association
or corporation, or a governmental unit, public utility or any other
legal entity whatsoever which is recognized by law as the subject
of rights and duties.
Any area not defined as impervious.
A culvert, closed conduit, or similar structure (including
appurtenances) that conveys stormwater.
The Harrisburg Planning Commission.
Any discernible, confined, or 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.
The flood that may be expected from the most severe combination
of critical meteorological and hydrologic conditions that are reasonably
possible in any 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).
The specific area of land where any regulated activities
in the City of Harrisburg are planned, conducted, or maintained.
Any person licensed by the Pennsylvania Department of State
or otherwise qualified by law to perform the work required by this
Part 9.
A rainfall-runoff relation used to estimate peak flow only.
Earth disturbance activities on land which has previously
been disturbed or developed.
Any earth disturbance activity or any activity that involves
the alteration or development of land in a manner that may affect
stormwater runoff.
Activity involving earth disturbance subject to regulation
under 25 Pa. Code Chapter 92, Chapter 102, or the Clean Streams Law.[1]
The percentage of predevelopment peak rate of runoff from
a site or subwatershed area to which the post-development peak rate
of runoff must be reduced to protect downstream areas.
Those subwatershed areas in which post-development flows
must be reduced to a certain percentage of predevelopment flows as
required to meet the plan requirements and the goals of Act 167.
The volume of runoff that is captured and not released directly
into the surface waters of this commonwealth during or after a storm
event.
The average interval, in years, within which a storm event
of a given magnitude can be expected to recur. For example, the probability
of a twenty-five-year storm occurring on any one given year is 0.04
(i.e., a 4% chance).
A vegetated area, bordering perennial and intermittent streams
and wetlands, that serves as a protective filter to help protect streams
and wetlands from the impacts of adjacent land uses.
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 right-of-way,
such as grading and repairing existing unpaved road surfaces, cutting
road banks, cleaning or clearing drainage ditches, and other similar
activities. Road maintenance activities that do not disturb the subbase
of a paved road, such as milling and pavement overlays, are not considered
earth disturbance activities.
Temporary ponding and gradual release of stormwater falling
directly onto flat roof surfaces by incorporating controlled-flow
roof drains into building designs.
Any part of precipitation that flows over the land surface.
The volume of runoff that is captured (retained) and not
released into surface waters of the commonwealth during or after a
storm event.
Soils or other materials transported by surface water as
a product of erosion.
The process by which mineral or organic matter is accumulated
or deposited by the movement of water.
A barrier, dam, retention or detention basin located and
designed to retain rock, sand, gravel, silt, or other material transported
by stormwater runoff.
The placement, discharge, or any other introduction of sediment
into the waters of the commonwealth occurring from the failure to
properly design, construct, implement or maintain control measures
and control facilities in accordance with the requirements of this
Part 9.
An area of excavated earth filled with loose stone or similar
coarse material, into which surface water is directed for infiltration
into the ground.
Runoff that flows over the ground surface as a thin, even
layer, not concentrated in a channel.
A method of runoff computation developed by the NRCS that
is based on relating soil type and land use/cover to a runoff parameter
called "curve number" (CN).
A depression in the embankment of a pond or basin, or other
overflow structure, that is used to pass peak discharge greater than
the maximum design storm controlled by the pond or basin.
The regulatory requirements to protect, maintain, reclaim,
and restore water quality under Title 25 of the Pennsylvania Code
and the Clean Streams Law,[2] including, but not limited to:
Each stream segment in Pennsylvania has a designated use, such
as "cold water fishery" or "potable water supply," which are listed
in Chapter 93. These uses must be protected and maintained, under
state regulations.
"Existing uses" are those attained as of November 1975, regardless
whether they have been designated in Chapter 93. Earth disturbance
activities must be designed to protect and maintain existing uses
and maintain the level of water quality necessary to protect those
uses in all streams and to protect and maintain water quality in special
protection streams.
Water quality involves the chemical, biological, and physical
characteristics of surface water bodies. After earth disturbance activities
are complete, these characteristics can be impacted by addition of
pollutants, such as sediment, and changes in habitat through increased
flow volumes and/or rates as a result of changes in land surface area
from those activities. Therefore, permanent discharges to surface
waters must be managed to protect the stream bank, streambed, and
structural integrity of the waterway, to prevent these impacts.
Protection and maintenance of water quality in special protection
streams pursuant to 25 Pa. Code Chapter 93.
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 also "return
period."
Drainage runoff from the surface of the land resulting from
precipitation, snow, or ice melt.
A land use or activity that generates higher concentrations
of hydrocarbons, trace metals, or toxicants than are found in typical
stormwater runoff.
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 detention and retention basins, wet ponds, open channels,
storm sewers, pipes and infiltration structures.
The Dauphin County Stormwater Management Plan for managing
stormwater runoff in Dauphin County as required by the Act of October
4, 1978, P.L. 864 (Act 167), and known as the "Stormwater Management
Act."
The plan, prepared by the applicant or his representative,
indicating how stormwater runoff will be managed at the project site
in accordance with this Part 9.
A bridge, culvert, or other structure in excess of 100 feet
in length upstream to downstream which encloses a regulated waters
of the commonwealth.
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, 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 dwellings shall be exempt (Pennsylvania Municipalities
Planning Code, Act of July 31, 1968, P.L. 805, No. 247).
The smallest drainage unit of a watershed for which stormwater
management criteria have been established in the stormwater management
plan.
A low-lying stretch of land that gathers or carries surface
water runoff.
See "forest management."
The time 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.
To finish the surface of a roadbed, top of embankment or
bottom of excavation.
The United States Department of Agriculture.
A channel or conveyance of surface water, such as a stream
or creek, having defined bed and banks, whether natural or artificial,
with perennial or intermittent flow.
The region or area drained by a river, watercourse, or other
body of water, whether natural or artificial.
Rivers, streams, creeks, rivulets, impoundments, ditches,
watercourses, storm sewers, lakes, dammed water, wetlands, ponds,
springs and 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.
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, including
swamps, marshes, bogs and similar areas. (The term includes but is
not limited to wetland areas listed in the State Water Plan, the United
States Forest Service Wetlands Inventory of Pennsylvania, the Pennsylvania
Coastal Zone Management Plan and a wetland area designated by a river
basin commission. This definition is used by the United States Environmental
Protection Agency and the United States Army Corps of Engineers.)
