[Ord. 1741, 3/17/2003, Section 101; amended by Ord. 1774,
3/2/2004, Section 1; Ord. 2049, 10/6/2014{60}]
The governing body of the Borough of State College finds that:
a.
Inadequate maintenance of stormwater best management practices (BMPs)
causes loss of water quality, flooding and threatens public health
and safety.
b.
Federal and state regulations require the Borough to obtain a permit
for discharges from its MS4 and to implement a program of stormwater
controls.
c.
A comprehensive program of reasonable regulation of connections and
discharges to municipal stormwater management facilities is fundamental
to the public health, safety, welfare, and the protection of the people
of the Borough of State College and all the people of the Commonwealth,
their resources, and the environment.
d.
It shall be illegal to discharge non-stormwater to the Borough owned
separate storm sewer system. Nothing in this ordinance shall affect
a discharger's responsibilities under state law.
e.
Stormwater is an important resource.
[Ord. 1741, 3/17/2003, Section 102; amended by Ord. 2049,
10/6/2014]
The purpose of this ordinance is to promote health, safety,
and welfare within the Borough of State College through provisions
designed to:
a.
Manage accelerated runoff, erosion, aggradation and degradation of
streams, channels and drainage ways.
b.
Meet NPDES MS4 requirements.
c.
Meet state water quality requirements.
d.
Maintain existing flows and quality of streams and watercourses and
drainways in the Borough of State College and the Commonwealth.
e.
Preserve and restore the flood-carrying capacity of streams.
f.
Provide proper maintenance of all permanent stormwater management
facilities that are constructed in the Borough.
g.
Provide procedures and for stormwater management and planning.
h.
Protect groundwater and surface water quality.
[Ord. 1741, 3/17/2003, Section 103; amended by Ord. 2049,
10/6/2014]
The Borough of State College is empowered to regulate land use
activities that affect runoff by the authority by 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 Home Rule Charter and
Optional Plan Law, 53 Pa.C.S.A. § 2961.
[Ord. 1741, 3/17/2003, Section 104; amended by Ord. 2049,
10/6/2014]
This ordinance shall apply to all land, streams, drainage ways
and watercourses within the Borough of State College.
This ordinance shall only apply to permanent stormwater management
facilities constructed as part of any of the Regulated Activities
listed in this section and to the Ownership and Maintenance of said
facilities and BMPs. Stormwater management and erosion and sediment
pollution control during construction activities are specifically
not regulated by this ordinance, but shall continue to be regulated
under existing laws and ordinances.
The following activities are defined as "Regulated Activities"
and shall be regulated by this ordinance:
a.
Land development;
b.
Subdivision;
c.
Construction of new or additional impervious or semi-pervious surfaces
(roadways, driveways, parking lots, etc.);
d.
Construction of new buildings or additions to existing buildings;
e.
Diversion or piping of any natural or man-made stream channel;
f.
Installation, modification, extension, revision and repair of stormwater
management facilities or appurtenances thereto.
g.
Land Disturbance.
[Ord. 2049, 10/6/2017]
Ordinance 1741 enacted March 17, 2003 and Ordinance 1774 enacted
March 1, 2004 are hereby repealed, in their entirety.
[Ord. 2049, 10/6/2017]
Should any section or provision of this ordinance be declared
invalid, unconstitutional, or unenforceable by a court of competent
jurisdiction, such decision shall not affect the validity of any of
the remaining provisions of this ordinance.
[Ord. 2049, 10/6/2017]
Approvals issued pursuant to this ordinance 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, rules, statutes, or ordinances.
[Ord. 1741, 3/17/2003, Section 107; amended by Ord. 1774,
3/2/2004, Section 2; amended by Ord. 2049, 10/6/2014]
a.
The granting of any exemption, permit, or approval by the Borough
does not relieve the applicant from assuring that stormwater runoff
from the development site will not cause injury or damage to other
persons or property.
b.
No person shall allow, or cause to allow, stormwater discharges into
the Borough's separate storm sewer system which are not composed entirely
of stormwater except (1) as provided in § 14-213m of this
ordinance and (2) discharges allowed under a state or federal permit.
c.
No person shall allow, or cause to allow, the connection of any drain
or conveyance to the Borough's separate storm sewer system, whether
on the surface or subsurface, which allows any non-stormwater discharge
including sewage, process wastewater, and wash water, to enter the
separate storm sewer system, or any connection to the separate storm
sewer system from indoor drains and sinks. No drain or conveyance
connected from a commercial or industrial land use shall be allowed
to connect to the separate storm sewer system which has not been documented
in plans, maps, or equivalent records and approved by the Borough
Engineer. The owner of such commercial or industrial land use drain
or conveyance system shall provide satisfactory evidence that such
discharge meets the discharge criteria of this ordinance.
[Ord. 1741, 3/17/2003, Section 108; amended by Ord. 2049,
10/6/2014]
Specific methods and publications indicated in this ordinance
shall, in all cases, refer to the latest available edition and include
revisions or amendments thereto.
[Ord. 1741, 3/17/2003, Section 109; amended by Ord. 2049,
10/6/2014]
Activities identified below are exempt from the requirement
to submit a Stormwater Management Site Plan to the Borough for review.
Exemption shall not relieve the applicant from implementing such measures
as are necessary to protect health, safety, and property. These measures
include adequate and safe conveyance of stormwater on the site and
as it leaves the site. This exemption shall not relieve the applicant
from meeting the special requirements for water quality and groundwater
recharge for high quality (HQ) and exceptional value (EV) watersheds
(PA DEP Chapter 93 and anti-degradation requirement), and § 14-216c
and e of this ordinance relative to recharge and water quality volume
requirements.
a.
All development and subdivision activities which have impervious
coverage of less than 10% of the total site area up to a maximum impervious
area of 2,500 square feet. However, adequate and safe conveyance of
stormwater from the site must be provided. For developments that are
to be constructed in phases, the sum of all final phases must be considered
in establishing exemption eligibility. Impervious cover may include,
but not be limited to, any roof, parking or driveway areas, and any
new streets and sidewalks, or bikeway utilizing impervious materials.
b.
Land disturbance associated with the construction or alteration of
one- and two-family dwellings, provided that the disturbance does
not alter any stormwater condition beyond the boundaries of the lot
or alter provisions of a previously approved Stormwater Management
Plan for the lot or encompassing subdivision. Multiple (>2) lot subdivisions
cannot be exempted.
c.
Any site less than one acre in size that decreases the total site
impervious area following development, and:
(1)
Is not located within a recognized sensitive area (as defined
in § 14-212, Definitions, of this ordinance);
(2)
Is not defined as a water quality sensitive (WQS) development
(as defined in § 14-212, Definitions, and Appendix B, Maps);
or
(3)
Is not located in an area where existing downstream stormwater
problems are known to occur (the Borough Engineer shall make the final
determination as to preexisting problems, but the Borough must be
supplied with supporting documentation of past problems).
d.
In addition, the Borough Engineer may waive the requirement to prepare
a stormwater management site plan for sites larger than 1.0 acre for
which the overall site impervious area is being decreased, and which
meets the other conditions identified above.
e.
Agriculture and Silviculture activities as defined in § 14-212,
Definitions, that are conducted according to requirements of 25 Pa.
Code 102.
f.
Property
and stormwater facilities owned and/or controlled by the Borough of
State College and used for public purposes are excluded from the provisions
of the within ordinance.
The diversion or piping of any natural or man-made stream channel
and/or for the installation of stormwater management facilities or
modifications thereto cannot be exempted. These activities always
require the submission of a Stormwater Management Site Plan. Exemptions
in Subsections a and b of this section cannot be combined for use
with small residential subdivisions.
In addition to the general exemptions identified above, exemptions
for specific technical criteria are identified where applicable in
§ 14-214.
[Ord. 2049, 10/6/2014]
Any approval or authorization issued or approved based on false,
misleading or erroneous information provided by an applicant is invalid
following notification. Any work undertaken or use established pursuant
to such approval or other authorization is unlawful. No action shall
be taken by a board, commission, council, department or employee of
the Borough purporting to validate such a violation.
[Ord. 1741, 3/17/2003, Section 110; amended by Ord. 2049,
10/6/2014]
For the purposes of this Part B, certain terms and words used
herein shall be interpreted as presented below. Additional definitions
are provided in the Act 167 Plan.
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, 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".
f.
AGRICULTURAL ACTIVITIES
ALTERATION
APPLICANT
BMP (BEST MANAGEMENT PRACTICE)
BOROUGH
BOROUGH ENGINEER
BUFFER AREA
CAPTURE DEPTH
CARBONATE
CHANNEL
CLOSED OR UNDRAINED DEPRESSION
CONSERVATION DISTRICT
CREDITS
DAM
DESIGN STORM
DESIGNEE
DETENTION BASIN
DEVELOPER
DEVELOPMENT SITE
DISCHARGER
DOLOMITE
DOWNSLOPE PROPERTY LINE
DRAINAGE CONVEYANCE FACILITY
DRAINAGE EASEMENT
DRAINAGE-WAY
EARTH DISTURBANCE ACTIVITY
EROSION
EROSION AND SEDIMENT POLLUTION CONTROL PLAN
EXFILTRATION
EXISTING CONDITIONS
FLOOD
FLOODPLAIN
FLOODWAY
FOREST MANAGEMENT/TIMBER OPERATIONS
FREEBOARD
GRASSED WATERWAY
GROUNDWATER RECHARGE
HYDROLOGIC SOIL GROUP
IMPERVIOUS SURFACE (AREA)
IMPOUNDMENT
INFILTRATION RATE
INLET
INTERCEPTOR
KARST
LAND DEVELOPMENT
LAND/EARTH DISTURBANCE
LAND USE
LIMESTONE
LINEAMENTS
MAIN STEM (MAIN CHANNEL)
MINIMUM ALLOWABLE DISCHARGE
MS4
NATURAL CONSERVATION AREAS
NPDES
NRCS
OUTFALL
OUTLET
PA DEP
PaDOT
PEAK DISCHARGE
PERCOLATION RATE
PIPE
PLANNING COMMISSION
POINT DISCHARGE
PROJECT SITE
QUALIFIED PROFESSIONAL
RECHARGE VOLUME
REGULATED ACTIVITIES
REGULATED EARTH DISTURBANCE ACTIVITY
RETENTION BASIN
RETURN PERIOD
RUNOFF
SAFE PASSAGE
SCOUR
SEDIMENT BASIN
SENSITIVE (WATER QUALITY) AREA
SENSITIVE RECHARGE AREA
SEPARATE STORM SEWER SYSTEM
SHEET FLOW
SINKHOLE
SPILLWAY
STABILIZATION
STATE WATER QUALITY REQUIREMENT
STORM SEWER
STORMWATER
STORMWATER MANAGEMENT FACILITY
STORMWATER MANAGEMENT PLAN
STORMWATER MANAGEMENT SITE PLAN
STRATA
STRATIGRAPHIC UNIT
STRUCTURAL FILL
SUBAREA
SWALE
SWM
TOPOGRAPHY
UNDETAINED AREA
WATER QUALITY DEPTH
WATER QUALITY SENSITIVE (WQS) DEVELOPMENT
WATER QUALITY VOLUME
WATER TABLE
WATERS OF THE COMMONWEALTH
WATERSHED
WETLAND
Definitions.
The work of producing crops and raising livestock including
tillage, plowing, disking, harrowing, pasturing 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 developer who has filed an application for
approval to engage in any Regulated Activities as defined in § 14-204
of this ordinance.
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 Ordinance. Stormwater BMPs
are commonly grouped into one of two broad categories or measures:
"structural" or "nonstructural." In this Ordinance, 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.
The Borough of State College, Centre County, Pennsylvania.
A professional engineer licensed in the Commonwealth of Pennsylvania
and duly appointed by the Borough of State College as their representative.
In the event that a Stormwater Utility is formed, all references to
the Borough Engineer shall be considered to also imply the Stormwater
Utility Engineer.
Area that is protected from development in order to prevent
degradation of the water body or water quality.
Depth of runoff captured from a given area and either allowed
to evaporate, infiltrate, or be discharged through a spillway at a
negligible rate.
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.
A perceptible natural or artificial waterway, which periodically
or continuously contains moving water having a definite bed and banks,
which confine the water.
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.
The Centre County Conservation District.
A deduction from the required amount. In this ordinance,
implies reduction of required water quality volumes due to using a
recommended practice.
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 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 governing body and/or agent of the governing body involved
with the administration, review or enforcement of any provisions of
this ordinance by contract or memorandum of understanding.
An impoundment structure designed to manage stormwater runoff
by temporarily storing the runoff and releasing it at a predetermined
rate.
A person, partnership, association, corporation, or other
entity, or any responsible person therein or agent thereof, that undertakes
any Regulated Activity of this ordinance.
The specific tract of land for which a Regulated Activity
is proposed.
One who discharges to the municipal separate storm sewer
system.
(1) A mineral consisting of calcium magnesium carbonate found
as compact lime stone; or (2) limestone or marble rich in magnesium
carbonate.
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 public or private land for stormwater management purposes.
The natural or man-made path of surface water from a given
area.
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.
The movement of soil particles by the action of water, wind,
ice, or other natural forces.
A plan that is designed to minimize accelerated erosion and
sedimentation.
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.
The initial condition of a project site prior to the proposed
construction.
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.
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
— Mapped as being a special flood hazard area.
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 natural or constructed waterway, usually broad and shallow,
covered with erosion-resistant grasses, used to conduct surface water
from cropland.
Replenishment of existing natural underground water supplies.
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 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)
A surface that prevents the infiltration 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 street or sidewalk. Decks,
parking areas, and the driveway areas are not counted as impervious
areas if they do not prevent infiltration.
A retention or detention basin designed to retain stormwater
runoff and release it at a controlled 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.
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 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.
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).
Inclusion of any or all of the following meanings: (i) 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; (ii) Any subdivision of land;
(iii) Development in accordance with Section 503(1.1) of the Pennsylvania
Municipalities Planning Code.
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.
The use employed in an area.
A rock that, by accumulation of organic remains, consists
mainly of calcium carbonate.
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.
Any stream segment or other runoff conveyance facility used
as a reach in the Spring Creek hydrologic model.
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 pre-development runoff estimate.
Municipal Separate Storm Sewer System.
A natural area protected during development for its water
quality or recharge enhancing abilities.
National Pollution Discharge Elimination System.
National Resources Conservation Service.
Point where water flows from a conduit, stream, or drain.
Points of water disposal from a stream, river, lake, tidewater
or artificial drain.
Pennsylvania State Department of Environmental Protection.
Pennsylvania State Department of Transportation.
The maximum rate of stormwater runoff from a specific storm
event.
The rate at which water moves through a soil profile. Percolation
rates are measured in units of time/length.
A culvert, closed conduit, or similar structure (including
appurtenances) that conveys stormwater.
The Planning Commission of the Borough of State College.
The discharge from a pipe or channel that concentrates runoff
at a single area.
The specific area of land where any regulated activities
in the Borough of State College 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
ordinance.
The volume of water that is required to be recharged from
developed sites.
Actions or proposed actions that have an impact on stormwater
runoff and that are specified in § 14-204 of this ordinance.
Activity involving earth disturbance subject to regulation
under 25 Pa. Code 92a, 25 Pa. Code 102, and/or the Clean Streams Law.
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.
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 4% probability of occurring in any given
year.
Any part of precipitation that flows over the land surface.
The routing of peak runoff events, usually the one-hundred-year
design event, safely through a structure without failure of that structure.
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.
A barrier, dam, retention or detention basin located and
designed to retain rock, sand, gravel, silt, or other material transported
by water.
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.
An undeveloped area that has significant benefit to the groundwater
recharge of stormwater.
A separate non-sanitary system reserved for storm sewer discharge.
Runoff that flows over the ground surface as a thin, even
layer, not concentrated in a channel.
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.
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.
The proper placing, grading and/or covering of soil, rock
or earth to ensure their resistance to erosion, sliding or other movement.
The regulatory requirements to protect, maintain, reclaim,
and restore water quality under Title 25 of the Pennsylvania Code
and the Clean Streams Law.
A system of pipes and/or open channels that convey 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 or snow or ice melt.
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, open channels, storm
sewers, pipes, and infiltration structures.
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.
The plan prepared by the developer or his representative
indicating how stormwater runoff will be managed at the development
site in accordance with this Ordinance. Stormwater Management Site
Plan will be designated as SWM Site Plan throughout this Ordinance.
The contents of the SWM Site Plan are established in § 14-222.
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.
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.
For the purposes of this ordinance, shall imply 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.
The smallest drainage unit of a watershed for which stormwater
management criteria have been established in the Stormwater Management
Plan.
A natural low-lying stretch of land or minor man-made conveyance
channel, which gathers or carries surface water runoff.
Stormwater management.
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.
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.
Depth of precipitation required to be used in computing the
water quality volume based on the percentage of imperviousness of
a site.
Land development projects that have a high potential to cause
catastrophic loss to local water quality and could potentially threaten
ground water reservoirs. See § 14-214 for additional definition.
Volume of runoff required to be controlled from a site in
a water quality BMP.
Upper surface of a layer of saturated material in the soil.
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.
The entire region or area drained by a river or other body
of water, whether natural or artificial, a drainage basin or sub-basin.
Those areas that are inundated or saturated by surface or
ground water 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.
[Ord. 1741, 3/17/2003, Section 111; amended by Ord. 1774,
3/2/2004, Section 3; Ord. 2049, 10/6/2014]
a.
All regulated activities in the Borough of State College which do
not fall under the exemption criteria shown in § 14-210
of this ordinance shall submit a SWM Site Plan to the Borough for
review. This plan must be consistent with the Spring Creek Watershed
Stormwater Management Plan. These criteria shall apply to the total
proposed development even if development is to take place in phases.
Impervious cover shall include, but not be limited to, any roof, parking
or driveway areas, and any new streets and sidewalks. Any areas designed
to initially be gravel or crushed stone shall be assumed to be impervious
for the purposes of comparison to the waiver criteria. The PA DEP
Stormwater BMP Manual, as amended and updated, shall be used for design
of stormwater management facilities. No disturbance may be performed
prior to approval of a SWM Site Plan. All activities (especially earth
disturbance activities) must comply with this ordinance, Title 25
PA Code, as amended and updated, and the Clean Streams Law, 35 P.S.
§ 691.1 et seq., as may be amended from time to time.
b.
Stormwater drainage systems shall be provided in order to permit
unimpeded flow along natural watercourses, except as modified by stormwater
management facilities or open channels consistent with this ordinance.
(1)
Stormwater management facilities and related installations also
shall be provided:
(a)
To ensure adequate drainage of all low points along the curbline
of streets.
(b)
To intercept stormwater runoff along streets at intervals reasonably
related to the extent and grade of the area drained, and to prevent
substantial flow of water across intersections or flooded intersections
during storms, in accordance with the procedures contained in Design
Manual Part 2 (DM-2), Chapter 10, of the Pennsylvania Department of
Transportation (PaDOT).
(c)
To ensure adequate and unimpeded flow of stormwater under driveways
in, near, or across natural watercourses or drainage swales. Suitable
pipes or other waterways shall be provided as necessary.
(d)
To properly drain stormwater runoff from all land development
projects, except as required by recharge criteria. All lot and open
areas shall be designed to drain to the nearest practical street or
drainage system, existing or proposed, as defined by the Borough Engineer,
with no impact on adjoining properties, unless an area specifically
designed for stormwater detention is provided.
c.
The existing points of concentrated drainage that discharge onto
adjacent property shall not be altered without permission of the altered
property owner(s) and shall be subject to any applicable discharge
criteria specified in this ordinance.
d.
Areas of existing diffused drainage discharge shall be subject to
any applicable discharge criteria in the general direction of existing
discharge, whether proposed to be concentrated or maintained as diffused
drainage areas, except as otherwise provided by this ordinance. If
diffused flow is proposed to be concentrated and discharged onto adjacent
property, the developer must document that adequate downstream conveyance
facilities exist to safely transport the concentrated discharge, or
otherwise prove that no erosion, sedimentation, flooding or other
harm will result from the concentrated discharge. If, in the opinion
of the Borough Engineer, there will be an impact on downstream property,
the Borough may require that the developer obtain a stormwater easement.
e.
Where a development site is traversed by watercourses, drainage easements
shall be provided conforming to the line of such watercourses. The
terms of the easement shall prohibit excavation, the placing of fill
or structures, and any alterations that may adversely affect the flow
of stormwater within any portion of the easement. Developers are encouraged
to allow watercourses and streams areas to revert to a natural condition.
Mowing or similar types of vegetation control are discouraged while
removal of invasive species are encouraged.
f.
When it can be shown that, due to topographic conditions, natural
drainage ways on the site cannot adequately provide for drainage,
open channels may be constructed conforming substantially to the line
and grade of such natural drainage ways. Work within natural drainage
ways shall be subject to approval by PA DEP through the Joint Permit
Application process, or, where deemed appropriate by PA DEP, through
the General Permit process.
g.
Any stormwater management facilities regulated by this ordinance
that would be located in or adjacent to waters of the Commonwealth
or wetlands shall be subject to approval by PA DEP through the Joint
Permit Application process, or, where deemed appropriate by PA DEP,
the General Permit process. When there is a question whether wetlands
may be involved, it is the responsibility of the developer or his
agent to show that the land in question cannot be classified as wetlands,
otherwise approval to work in the area must be obtained from PA DEP.
h.
Any stormwater management facilities regulated by this ordinance
that would be located on State highway rights-of-way shall be subject
to approval by the Pennsylvania Department of Transportation (PENNDOT).
i.
Low Impact Development (LID) is to be used to maximum extent practicable.
Minimization of impervious surfaces and infiltration of runoff through
seepage beds, recharge trenches, etc., are encouraged, where soil
conditions permit, to reduce the size or eliminate the need for detention
facilities.
j.
To promote overland flow and infiltration/percolation of stormwater,
roof drains should not be connected to streets, storm sewers, or roadside
ditches unless approved by the Borough Engineer on a case-by-case
basis.
k.
Where deemed necessary by the Borough Engineer, the applicant shall
submit an analysis of the impacts of detained stormwater flows on
downstream areas within the watershed. These impacts shall be identified
with concurrence from the Borough Engineer. The analysis shall include
hydrologic and hydraulic calculations necessary to determine the impact
peak discharge modifications from the proposed development have on
critical locations such as dams, tributaries, existing developments,
undersized culverts, flood-prone areas, etc.
l.
When stormwater management facilities are proposed within 1,000 feet
of a downstream municipality, the analysis of downstream impacts shall
be submitted to the downstream municipality's engineer or designated
representative for review and comment.
m.
Non-stormwater discharges which may be allowed to the Borough's separate
storm sewer system, based upon a finding by the Borough Engineer that
the discharges do not significantly contribute to pollution to surface
waters of the Commonwealth are:
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Discharges from firefighting activities
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Potable water sources including dechlorinated water line and
fire hydrant flushing
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Irrigation drainage
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Routine external building wash-down (which does not use detergents
or other compounds)
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Air conditioning condensate
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Water from individual residential car washing
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Springs
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Water from crawl space pumps
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Uncontaminated water from foundation or from footing drains
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Flows from riparian habitats and wetlands
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Lawn watering
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Pavement wash waters where spills or leaks of toxic or hazardous
materials have not occurred (unless all spill material has been removed)
and where detergents have not been used
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Dechlorinated swimming pool discharges
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Uncontaminated groundwater
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Diverted stream flow
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Uncontaminated pumped groundwater
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n.
The applicant shall provide the Borough with all names and addresses
of adjacent property owners. The property shall be posted in a conspicuous
location of the potential development and copies of the notification
shall be sent by the Borough via United States regular mail. Notification
to include the following language: "A land development plan is being
considered by the Borough of State College for Tax Parcel (insert
parcel number) as shown on the attached exhibit. Written comments
may be directed to the Borough of State College at 243 South Allen
Street, State College, PA 16801."
o.
Approved SWM Site Plans must be on site at all times during construction.
p.
Use of Alternate and/or new Stormwater Management Controls will be
considered by the Borough. A description of the proposed alternate
controls must be submitted to the Borough, the Centre County Conservation
District, and to the PA DEP. The Borough will coordinate any approvals
with the CCCD and/or PA DEP.
q.
The SWM Site Plan must contain a proper long term Ownership, Operation
and Maintenance Plan in accordance with § 14-231 of this
ordinance.
[Ord. 1741, 3/17/2003, Section 112; amended by Ord. 2049,
10/6/2014]
Sensitive areas and water quality sensitive developments have
been identified which require special consideration with regard to
stormwater management.
a.
Sensitive areas are defined as those areas that, if developed, have
the potential to cause catastrophic loss to a Water Authority well
field. These areas consist of the delineated one-year zone of contribution
and direct upslope areas tributary to the wells (see Appendix B, Exhibit
1 of the Spring Creek Watershed Action 167 Stormwater Management Plan).
Municipalities may update the sensitive area boundaries based on new
research or studies as required.
b.
Sensitive Recharge Areas are defined as those areas that in an undeveloped
state provide significant benefit to the recharge of stormwater.
c.
Water Quality Sensitive (WQS) developments are defined as a land
development project that has a high potential to cause catastrophic
loss to local water quality, and could potentially threaten ground
water reservoirs. The following is a provisional list of water quality
sensitive developments. This list may be amended at the discretion
of the Borough of State College.
Vehicle fueling stations
Industrial manufacturing sites*
Salvage yards
Recycling centers
Hazardous material storage areas*
Interstate highways
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*
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The Borough Engineer will make the determination relative to
what constitutes these classifications on a case-by-case basis. The
Pennsylvania DEP wellhead protection contaminant source list shall
be used as a guide in these determinations. Industrial manufacturing
site and hazardous material storage areas must provide NPDES SIC codes.
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[Ord. 1741, 3/17/2003, Section 113; amended by Ord. 2049,
10/6/2016]
a.
General. Post-development rates of runoff from any regulated activity
shall not exceed the peak release rates of runoff prior to development
for the design storms specified.
b.
Sensitive Area District Boundaries. The location of sensitive areas
or sensitive area districts (SAD) within the watershed are illustrated
on an Official Map, which is available for inspection at the municipal
office. A reduced scale copy of this map is included as Exhibit 1
in Appendix B. The exact location of the boundaries of sensitive areas
is set by drainage areas tributary to each of the points of interest
as illustrated in Appendix B. The exact location of these boundaries
as they apply to a given development site, shall be determined using
mapping at a scale which accurately defines the limits of the sensitive
area. If the project site is within the sensitive area (in whole or
in part), two-foot contour interval mapping shall be provided to define
the limits of the sensitive area. If the project site is adjacent
to but within 500 linear feet of a defined Sensitive Area, a five-foot
contour interval map defining the limits of the Sensitive Area shall
be included in the SWM Site Plan to document the site's location relative
to the sensitive area.
c.
Sites Located in More Than One District. For a proposed development
site which is traversed by a SAD boundary, the design criteria for
sensitive areas must be applied if post-development runoff is directed
towards the sensitive area.
d.
Off-Site Areas. Off-site areas that drain from sensitive areas through
a proposed development site that is located entirely in a non-sensitive
area are not required to use or apply the sensitive area criteria.
e.
Site Areas. Where the site area to be impacted by a proposed development
activity differs significantly from the total site area, only the
proposed impact area shall be subject to the design criteria.
f.
"Downstream Hydraulic Capacity Analysis." Any downstream or off-site
hydraulic capacity analysis conducted in accordance with these standards
shall use the following criteria for determining adequacy for accepting
increased peak flow rates:
(1)
Natural or man-made channels or swales must be able to convey
the post-development runoff associated with a two-year return period
event within their banks at velocities consistent with protection
of the channels from erosion. Acceptable velocities shall be based
upon criteria included in the PA DEP Erosion and Sediment Pollution
Control Program Manual.
(2)
Natural or man-made channels or swales must be able to convey
the post-development twenty-five-year return period runoff without
creating any hazard to persons or property.
(3)
Culverts, bridges, storm sewers or any other facilities which
must pass or convey flows from the tributary area must be designed
in accordance with PA DEP, Chapter 105 regulations (if applicable)
and, at a minimum, pass the post-development twenty-five-year return
period runoff.
(4)
It must be demonstrated that the downstream conveyance channel,
other stormwater facilities, roadways, or overland areas must be capable
of safely conveying the one-hundred-year design storm without causing
damage to buildings or other infrastructure.
(5)
Where the downstream conveyance channel or other facility is
located within a special flood hazard area (as documented on the municipal
Flood Insurance Rate Map), it must be demonstrated that the limits
of said flood hazard area are not increased by the proposed activity.
(6)
Stormwater management ponds that fall under the PA DEP Chapter
105 Criteria of a "Dam" must meet the criteria within Chapter 105.
[Ord. 1741, 3/17/2003, Section 114; amended by Ord. 2049,
10/6/2014]
Design criteria and calculation methodologies have been classified
by functional group for presentation as follows: peak runoff rate
discharge requirements; stormwater pond capture volumes; recharge
volumes; storm drain design including conveyance, channel protection,
and stability; and water quality standards.
These criteria and calculation methodologies have been developed
to simplify stormwater management designs, unify methods, remove model
parameter subjectivity, remove improperly used methods, and to ensure
stormwater management decisions are based more realistically on hydrologic
processes. In addition, common sense should always be used as controlling
criteria.
These standards provide consistent and process oriented design
procedures for application by land development professionals. It is
recognized that in an attempt to generalize the computational procedures,
assumptions have been made which on some occasions may be violated.
If such a violation is identified, alternate standards and procedures
may be applied. Both the violation and the alternate procedures to
be applied must be documented by a hydrologist or hydrogeologist.
Any request for use of alternate standards or procedures under this
provision must be agreed to by the Borough Engineer prior to formal
submission of plans for consideration by the Borough.
a.
Peak Runoff Rate Control.
(1)
Any site where the increase in post-development peak runoff
rates is determined to be negligible by the Borough Engineer is exempt
from the requirement to provide stormwater detention. In support of
this exemption, it must be shown that the downstream conveyance systems
have adequate capacity to convey the additional discharge without
adversely affecting downstream properties. This does not exempt the
requirement for implementation of designs for water quality, stormwater
conveyance, and/or recharge as required. A SWM Site Plan and report
documenting these design elements is also required. The Borough Engineer
shall use a 5% increase as a general benchmark for defining "negligible."
The final definition of "negligible" shall be at the Borough Engineer's
discretion.
Prior to using this exemption (and prior to any land development
plan submission), the Design Engineer must provide written documentation
and computations as to why no peak runoff control should be required.
The Borough Engineer has the right to reject any plan which uses this
assumption without prior approval of the Borough Engineer. The intent
of this exemption is to eliminate the need for multiple or "piggyback"
detention facilities as a result of minor changes in imperviousness
or land use upstream of existing stormwater control facilities.
(2)
Small sites (<5 acres) located directly adjacent to the main
stem of creeks or within the floodplain are not required to provide
stormwater detention unless directed to do so by the Borough Engineer
as a result of a documented drainage problem. All other stormwater
management standards must be implemented including water quality,
adequate stormwater conveyance, and/or recharge as required. The Borough
Engineer has the right to reject any plan that uses this exemption
without prior approval of the Borough Engineer.
(3)
Stormwater management analysis must be performed using the following
models. The size criteria are based on drainage area size including
site area and all off-site area draining across the development.
Up to 100 acres in size: NRCS's TR-55 or TR-20.
Over 100 acres in size: NRCS's TR-20 or HEC-1 (HEC-HMS).
The Modified Rational Method using the Gert Aron Curves may
be used for any site less than or equal to two acres in size without
prior authorization from the Borough Engineer. The Modified Rational
Method may also be used for sites between two and five acres in size
where the Borough Engineer has approved the method's use. In this
case the Design Engineer must make a written request to the Borough
Engineer explaining why the use of the Modified Rational Method is
more appropriate than the NRCS's methods for the site in question.
The Design Engineer should keep in mind that the Modified Rational
Formula methodology was not calibrated to account for the karst nature
of the Spring Creek Drainage Basin; and therefore, its use should
be limited to the special cases identified above. In addition, since
the minimum discharge criteria are based on a calibration of the NRCS
runoff mode, their use is not appropriate if the Modified Rational
Method is used for runoff computations.
The Borough Engineer has the right to reject any SWM design
that uses hydrograph combinations with the Modified Rational Method
where the designer has not validated that the effects of the timing
differences are negligible. In addition, the Borough Engineer has
the right to reject any SWM design that improperly uses the method
for determining runoff volumes or does not properly apply the method.
More intensive physically based models may be used at the discretion
of the Borough Engineer, but only for sites greater than 100 acres
in size.
Commercial software packages that use the basic computational
methods of TR-55 or TR-20 are permitted.
The NRCS models and methods recommended above are based on data
collected from actual watersheds. In contrast to this, stormwater
management analysis for land development activities is often conducted
using property lines to define drainage boundaries. Drainage areas
based on property boundaries are not true watersheds and are referred
to here as "hypothetical" drainage areas. It is known that these hypothetical
drainage areas do not respond like natural watersheds. Peak runoff
rates from hypothetical drainage areas are much smaller than comparable
runoff rates from natural watersheds of the same size. Therefore,
wherever possible, pre- and post-development stormwater analysis should
be conducted for watersheds that are as nearly natural as possible.
Also, conducting stormwater analysis for a lot by lot comparison,
such as within residential developments is not permitted. Partitioning
drainage areas into different sub-watersheds for the post-development
scenarios is acceptable.
It is noted that natural watershed boundaries should not be
used where the relative size of the watershed compared to the site
size would inappropriately distort the pre- to post-development runoff
comparison. In these cases a hypothetical drainage area defined by
the property boundary should be used because it will allow for a better
estimate of runoff changes directly downstream of the site. In addition,
the designer should recognize that, within the Spring Creek Watershed,
typical hypothetical drainage areas, in their pre-development or natural
condition, do not produce surface runoff during minor to moderate
rainfall events. Available hydrologic models do not accurately reflect
this condition. This often results in post-development nuisance flooding
since the models over-estimate the pre-development runoff magnitude.
(4)
Major natural drainage divides may not be altered without the
prior consent of the Borough Engineer.
(5)
Pre- and post-development stormwater management analysis shall
be conducted using the following design storms: one-year; two-year;
ten-year; one-hundred-year.
For sites less than one acre in total area that connect directly
to existing storm sewer systems, surface or subsurface (underground)
stormwater detention facilities only need to be designed to control
storm events up to the design return period of the existing pipes
(usually 10 years). However, it must be demonstrated that adequate
conveyance capacity (overland or within the existing storm sewer system)
exists to ensure that flooding or damage from proposed releases will
not exceed the existing potential for the system. If warranted by
historic flooding in the tributary storm sewer system, the Borough
may require more stringent criteria.
(6)
The twenty-four-hour precipitation depths as obtained from NOAA
Atlas 14 shall be used for stormwater management analysis.
(7)
The NRCS's Type II precipitation distribution is required for
all stormwater management analyses.
(8)
The NRCS's dimensionless unit hydrograph "k" factor shall be
484 for both pre- and post-development stormwater analyses.
(9)
All undeveloped areas are to be modeled as meadow or woods in
good hydrologic condition. Existing impervious areas may be modeled
as being impervious for pre-development conditions. The Borough may
require a percentage of the existing impervious be modeled as meadow
in areas where there are known existing stormwater concerns downstream
of the project area or where the site being developed has either deficient
or non-existing stormwater management facilities. Developers of sites
with existing impervious areas are highly encouraged to meet with
the Borough Engineer prior to design so that any additional requirements
are identified prior to plan submission.
(10)
The NRCS's curve number (CN) shall be used as the rainfall to
runoff transformation parameter for all stormwater management analyses.
(11)
Curve numbers should be rounded to tenths for use in pre-packaged
hydrologic models. It should be recognized that the CN is only a design
tool with a large degree of statistical variability. For large sites,
CN's should realistically be rounded to the nearest whole number.
(12)
The NRCS's method to determine unconnected impervious area adjustments
for CN can be used for distinctly defined impervious land areas that
flow onto pervious areas in a dispersed manner. The method may only
be used to calculate runoff from site impervious areas that actually
flow across pervious areas. The method cannot be applied to the entire
site using average weighted CN values.
(13)
Soils underlain by carbonate geology (limestone or dolomite)
shall have a hydrologic soil group (HSG) B used for both pre- and
post-development conditions regardless of the NRCS or Soil Survey's
description, except for the following two conditions:
(a)
Compacted structural fill areas shall use a minimum of HSG C
for post development conditions regardless of the NRCS or Centre County
Soil Survey's description. For most developments compacted structural
fill areas are under impervious surfaces, but may include islands
within parking areas, fringe land, etc. A HSG C shall also be applied
to large projects that clear and compact building pad areas for later
phases of development under an initial phase. The Borough Engineer
shall make the final determination as to what areas of a land development
site constitute compacted structural fill. The intent is to account
for large compacted areas, and not minor grading within lawn areas.
(b)
Soils identified as "on floodplains" or "on terraces above floodplains"
in the Centre County Soil Survey will use the HSG as designated in
the Soil Survey. Refer to Appendix A for a list of the soils.[1]
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
(14)
Soils not underlain by carbonate geology shall use the HSG as
specified by the NRCS or Soil Survey's description, except for the
following two conditions:
(a)
Wooded areas on HSG C and D soils shall be treated as HSG B
for pre-development conditions. Disturbed post-development wooded
areas shall carry the NRCS or Soil Survey's defined HSG with a minimum
HSG of B.
(b)
Highly compacted structural fill areas shall use a minimum of
HSG C for post-development conditions regardless of the NRCS or Soil
Survey's description. For most developments these areas are normally
covered with impervious surfaces, but may include islands within parking
areas, fringe land, etc. A HSG of C shall also be used for large projects
that clear and grade land for later phases of development. The Borough
Engineer shall make the final determination as to what areas of a
land development site constitute compacted structural fill. The intent
is to account for large compacted areas, and not minor grading within
lawn areas or small areas around buildings, etc.
(15)
Areas draining to closed depressions must be modeled by removing
the storage volume from the pre-development condition. The designer
may assume that infiltration in the closed depression does not occur
during a design runoff event. Areas draining to closed depressions
may also be used to adjust peak runoff rates to stormwater management
ponds for the post-development analysis. This allowance has been developed
to entice designers to intentionally design or leave in place small
closed depressions that can reduce the total volume required from
a stormwater management pond. The site designer is responsible to
document downstream impacts if the closed depression were removed.
(16)
Drainage areas tributary to sinkholes shall be excluded from
the modeled point-of-interest drainage areas defining pre-development
peak flows. Assumptions that sinkholes spill-over during some storm
events must be supported by acceptable documentation (as determined
by the Borough Engineer). In addition, the design professional must
be aware that bypassing or sealing sinkholes will frequently result
in downstream flooding and should not be done if existing downstream
flooding already occurs. The site designer is responsible to document
downstream impacts if the sinkhole were to stop taking stormwater
runoff.
(17)
Ponds or other permanent pools of water are to be modeled by
the methods established in the NRCS's TR-55 manual (1986). However,
more rigorous documented methods are acceptable (as determined by
the Borough Engineer).
(18)
The NRCS antecedent runoff condition II (ARC II, previously
AMC II) must be used for all simulations. The use of continuous simulation
models that vary the ARC are not permitted for stormwater management
purposes. In addition, prior to any continuous simulation model being
used in the Spring Creek Basin for any other purposes, the model unit
hydrograph must be modified for common events in additional to extreme
events based on an in depth analysis of historical data from the basin.
(19)
The following Time of Concentration (Tc) computational methodologies
shall be used unless another method is pre-approved by the Borough
Engineer:
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Pre-development - NRCS's Lag Equation.
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Post-development; commercial, industrial, or other areas with
large impervious areas (>20% imperviousarea) - NRCS's Segmental Method.
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Post-development; residential, cluster, or other low impact
designs less than or equal to 20% impervious area - NCRS's Lag Equation.
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The time of concentration is to represent the average condition
that best reflects the hydrologic response of the area. For example,
large impervious areas bordered by small pervious areas may not consider
the effect of the pervious areas in the Tc computation. If the designer
wants to consider the effect of the pervious area, runoff from the
pervious and impervious areas must be computed separately with the
hydrographs being combined to determine the total runoff from the
area.
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Under no circumstance will the post-development Tc be greater
than the pre-development Tc for any watershed or sub-watershed modeling
purposes. This includes when the designer has specifically used swales
to reduce flow velocities. In the event that the designer believes
that the post-development Tc is greater, it will still be set by default
equal to the pre-development Tc for modeling purposes.
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[Refer to Subsection a(29) regarding impervious area flashing
(IAF).]
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(20)
The following post-development minimum discharges are permitted
for use with the NRCS (CN) runoff model*:
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One-year return period
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Qpmin = 0.018 (DA) + 0.2
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Two-year return period
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Qpmin = 0.03 (DA) + 0.4
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Ten-year return period
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Qpmin = 0.09 (DA) + 1.0
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Where:
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DA
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=
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the drainage area in acres
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Qpmin
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=
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minimum allowable peak runoff rate in cfs
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For return periods greater than 10 years, the minimum discharge
shall be equal to the computed pre-development peak runoff rate.
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The minimum discharge criteria above are not appropriate for
use with the Rational Method. This is because these values were developed
based on NRCS model corrections and do not actually represent a true
physical process or discharge. However, common sense should be used
by both the designer and reviewer in the evaluation of acceptable
minimum discharges for use with the Rational Method.
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The intent of the minimum discharge is to allow reasonable runoff
release from a site when a hydrologic model has produced a pre-development
runoff rate close to zero. The method is NOT permitted for areas that
previously drained completely to sinkholes in order to bypass the
sinkhole after development.
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These minimum discharge values include the total of all stormwater
management facilities discharges and undetained area discharges. Peak
runoff rates for undetained fringe areas (where the designer has made
a realistic effort to control all new impervious areas) will be computed
using the pre-development time of concentration for the drainage areas
tributary to them. Undetained areas are those portions of the site
that cannot be routed to a stormwater management facility due to topography
and typically include lower pond berms, or small areas around entrance
drives. The site drainage areas used shall represent the pre-development
condition, even if drainage areas are altered following development.
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(21)
All lined stormwater management ponds in carbonate and non-carbonate
areas must be considered impervious and may not be used as pervious
areas for stormwater management computations. "Lined" here means lined
with synthetic liners or bentonite. All other compacted soil liners
will be considered to be HSG D for hydrologic computations.
(22)
Stormwater management ponds that have a capture depth for the
purposes of water quality or volume capture shall assume a negligible
discharge from these structures during design event routing. Only
discharges from the primary principal spillway or emergency spillway
need to be considered. Discharges from subsurface drains that tie
into a principal spillway should not be considered during design event
routing. All subsurface drains are to be equipped with a restrictor
plate with a one" opening in order to prevent the subsurface drain
from functioning as a primary orifice.
(23)
Stormwater management ponds that have a pond capture, recharge
or water quality component shall assume that the basin is full to
the controlling component volume at the beginning of design event
routing.
(24)
Stormwater management ponds must provide safe passage of the
one-hundred-year return period peak runoff rate assuming that all
of the principal spillway orifices are fully clogged, and the principal
spillway overflow is 50% clogged. A minimum of a six-inch freeboard
must also be maintained above the resulting "maximum" water surface
elevations (W.S.E.). Any embankment emergency spillway can be assumed
to be unclogged. SWM ponds with embankments completely made up of
natural undisturbed soils (fully in "cut") or where roadways act as
the emergency spillway are permitted. However, the Design Engineer
must verify downstream stability and control.
(25)
All pre- and post-development comparisons of peak flows shall
be rounded to tenths of a cfs. The intent here is to recognize the
accuracy and precision limitations of hydrologic modeling procedures.
Again, small differences between pre- and post-development discharge
rates should be permitted when no negative downstream impacts will
result.
(26)
The full Modified Puls routing method must be used for stormwater
management pond analyses. Simplified methods of determining pond size
requirements such as those in TR-55 (1986) can only be used for preliminary
pond size estimates.
(27)
Pre-packaged hydraulic programs are not approved for the analysis
of underground stormwater management facilities unless it can be verified
that the program rounding subroutines used for the stage/storage data
do not affect the results. This is because, for very small storage
volumes, the program may round off the volume to a significant percentage.
(28)
Full supporting documentation must be provided for all stormwater
management designs.
(29)
Designs must be checked for Impervious Area Flash (IAF). This
check is used to determine if flooding may occur due to poor modeling
choices specifically related to the time of concentration. This analysis
requires that the watershed impervious area be modeled without the
pervious areas. The time of concentration should also be determined
from the impervious areas only. If the IAF analysis results in a higher
peak runoff rate at a culvert or discharge from a pond, this higher
rate must be used for the final design/comparison. The check will
frequently yield higher values if a watershed's impervious area is
located primarily near the watershed outlet or point of interest.
b.
Pond Capture Volumes (Cv). To minimize nuisance flooding from small
precipitation events, a runoff capture volume is required for all
stormwater management ponds that do not discharge directly to natural,
well-defined (with bed and banks) perennial streams. In general, natural
well-defined streams in the Spring Creek Basin are limited to those
delineated as USGS perennial streams. This should be treated as a
guideline and not a steadfast rule. The final determination is at
the discretion of the Borough Engineer. The pond capture volume is
a volume of runoff that will be retained in a pond below the elevation
of any free surface principal spillway orifice. No principal spillway
orifice (except those connected to subsurface drains), regardless
of how small, shall be below the pond elevation equivalent to this
volume.
The Centre County Conservation District (CCCD) receives numerous
complaints regarding ponds that are located at the downslope edge
of a property that result in discharging runoff onto downstream properties
in an uncontrolled manner or where no existing defined outlet channel
exists. This is a very common problem in areas underlain by carbonate
rock. These discharges can cause erosion and flooding downstream.
While the Pond Capture volume is intended to minimize some of these
negative effects, it cannot deter or reduce the impacts from poor
design practices. Therefore, whenever possible, the CCCD recommends
that the designer consider the downstream morphological changes that
may occur and, when possible, consider constructing conveyance systems
to a stable natural channel. In some cases this may require cooperation
between landowners.
The capture volume is defined as a runoff depth of 0.25 inches
from all impervious areas tributary to the stormwater management facility.
This volume will be allowed to infiltrate, evaporate, or dewater from
a subsurface drain system connected directly to the facility's principal
spillway. Supporting computations that show that 90% of the capture
volume can dewater in a maximum of 72 hours must be provided. For
surface ponds, the maximum depth of ponding for the capture volume
shall be three feet (a health and safety precaution). However, in
areas under karst influence, a limiting maximum ponding depth of 18
inches is recommended. Designers may always increase the capture volume
to a value greater than the identified standard as long as the ponding
depth criteria are met.
To simplify computational requirements for design event analysis,
designers do not need to calculate discharges from subsurface drains
related to the capture volumes if the filter media is sand, or smaller
than AASHTO 57 stone. The capture volume is to control runoff rates
from impervious areas and is not related to water quality. However,
pond designs that include a water quality volume that is greater than
the required capture volume are assumed to have also met the required
capture volume as long as it dewaters as required.
Designs that rely on the natural infiltration of insitu soils
must provide documentation supporting the infiltration rates used
for analysis. Infiltration rates reported in the Soil Survey of Centre
County or other published rates may be used at the discretion of the
Borough Engineer.
The pond capture volume should always be used when up-slope
areas are developed where the pond's design creates a point discharge
that did not previously exist.
Stormwater management detention facilities that connect directly
to storm drain pipe networks that discharge to natural well-defined
channels do not require a capture volume.
c.
Recharge Volumes (Rv). The purpose of the recharge portion of the
ordinance is two-fold. First, the recharge requirement is to mitigate
the loss of groundwater recharge associated with the creation of impervious
surfaces. In addition the recharge criteria are to mitigate the increase
in runoff volume associated with the creation of impervious surfaces.
This increase in runoff volume has significant impacts on downstream
landowners. These impacts are most often exhibited in the form of
increased nuisance flooding and channel or drainage-way erosion and
instability. According to local Municipal Engineers and representatives
of the Centre County Conservation District, these problems are of
significant local concern. The magnitude of these problems increases
with the percentage of impervious coverage created on a site.
Recharge mitigation shall be provided for runoff from all proposed
impervious areas. The required recharge volume shall be computed as
0.5 inch of runoff from all proposed impervious areas. It is noted
that lined detention ponds and compacted fill areas are considered
to be impervious when calculating site impervious area for recharge
considerations. In addition, land areas covered by paver blocks, pervious
pavement, and other structural surface treatments which permit surface
infiltration can be treated as pervious areas when calculating the
site impervious area for recharge considerations as long as the structural
infiltration practice is supported by sound design and appropriate
construction specifications. The Borough Engineer may require submission
of supporting documentation prior to approving structural infiltration
areas as pervious areas.
The following design practices can be used as credits to reduce
the recharge volume requirement:
(1)
Residential Roof Areas (detached, duplex, and town home dwellings)
and commercial/industrial buildings with roof areas less than 5,000
square feet can be removed from the computed impervious area when
these roof areas are sumped to dry wells designed in accordance with
the following minimum standard:
SUMP DESIGN CRITERIA: To meet the recharge criteria, sump storage
or voids volume shall be equal to 0.04 cubic feet per square foot
of roof area (0.5 inch rainfall depth). If sump stone has a voids
ratio of 40%, the total sump volume will be 0.10 cubic feet per square
foot of roof area. When designed only to meet this recharge criteria,
the maximum size for a single sump is 100 cubic feet, and the minimum
sump surface area (A) to depth (D) ratio (A/D) must be a minimum of
4/1. The sump depth less any freeboard should not exceed 24 inches.
This roof sump standard shall apply unless the municipality has a
separate roof sump standard for water quantity or peak control.
(2)
All or portions of driveways, roadways, and parking areas can
be removed from the impervious area calculation when sheet flow from
these areas is directed to undisturbed natural buffer/filter areas
or constructed filter strips. This flow must be dispersed as sheet
flow as it crosses the buffer/filter area. Sheet flow velocities should
be non-erosive as they cross the impervious area/filter interface.
To ensure proper infiltration characteristics the natural soil
profile within natural buffer/filter areas cannot be disturbed during
construction. Completely undisturbed natural recharge areas serve
this function best. However, minor surface scaring, seeding, and landscaping
are permitted in these areas as long as natural grades are not altered.
In special cases, when approved by the Borough Engineer, minor grading,
combined with soil profile reconstruction may be permitted in natural
buffer/filter areas. In addition, the following standards apply to
natural filter/buffer areas:
(a)
Natural filter/buffer areas must have a minimum width of five
feet or 1/2 of the impervious area drainage length immediately tributary
to the buffer area, whichever is greater. This width is measured parallel
to the direction of sheet flow.
(b)
To qualify for a recharge volume credit, the surface slope of
natural filter/buffer areas must be conducive to recharge, and not
result in flow concentration or erosion.
To meet this intent, the surface slope of the area tributary
to the natural buffer/filter area, and the surface slope of the natural
buffer/filter area itself may not exceed 5%. In special cases steeper
slopes may be used if specifically authorized by the Borough Engineer.
(c)
The total impervious area tributary to a natural buffer/filter
area can not exceed twice the buffer/filter area.
|
To qualify for a recharge volume credit, constructed filter
strips shall be designed to the following standards:
| |
|
•
|
The minimum filter strip width shall be five feet or 1/2 of
the impervious area drainage length immediately tributary to the constructed
filter strip, whichever is greater. This width is measured parallel
to the direction of sheet flow.
|
|
•
|
The total impervious area tributary to a constructed filter
strip area can not exceed twice the constructed filter strip area.
|
|
•
|
The surface slope of the area tributary to the constructed filter
strip area, and the surface slope of the constructed filter strip
area itself may not exceed 5% and 3%, respectively. In special cases
steeper slopes may be used if specifically authorized by the Borough
Engineer.
|
|
•
|
The filter strip surface shall consist of a minimum of inches
of natural or reconstructed topsoil with a stable grass surface treatment.
Reconstructed topsoil designs must be approved by the Borough Engineer
prior to application. Reconstructed topsoil consists of soils augmented
by tillage and the addition of soil amendments such as compost, lime,
animal manures, crop residues, etc.
|
|
•
|
To minimize erosion of the topsoil layer during construction,
it is recommended that these areas be sodded. However, the Borough
Engineer may permit the use of an acceptable erosion control seeding
application. In this later case, any loss of topsoil and seed must
be replaced until a permanent vegetative stand is achieved.
|
(3)
Sidewalks separated from roadways and/or other impervious surfaces
by a grass strip of equal or greater width than the sidewalk itself
can be removed from the impervious area calculation when the sidewalks
are graded so that sheet flow from the walk is directed to the grass
strip. Sidewalks with steep longitudinal slopes that would act as
channels during runoff events cannot take advantage of this credit.
A 5% longitudinal sidewalk slope shall be used as the benchmark defining
steep slopes.
(4)
Impervious areas tributary to natural closed depressions can
be subtracted from the total site impervious area used in the recharge
volume calculation as long as a qualified geotechnical engineer or
soil scientist certifies to the soundness of these site specific applications.
Water quality pre-treatment may be necessary prior to the direct discharge
of runoff to existing closed depressions or sinkholes.
(5)
Impervious areas tributary to man-made closed depressions can
be subtracted from the total site impervious area as long as a qualified
geotechnical engineer or soil scientist certifies to the soundness
of these site-specific applications. Man-made closed depressions can
be created through the use of low head berms one foot or less in height.
(6)
Additional credits may apply for undisturbed land areas that
are known to have high infiltration capacity and that are maintained
or enhanced. These areas must be defined and quantified from actual
site data collection.
After credits, the remaining recharge volume shall be directed
to a Recharge BMP such as infiltration trenches, beds, etc. These
facilities can be located in open areas or under pavement structures.
The appropriateness of the particular infiltration practice proposed,
as well as the design parameters used, shall be supported by a geotechnical
report certified by a qualified professional (soil scientist, geologist,
hydrogeologist, geotechnical engineer, etc.).
Stormwater recharge requirements or credits affect stormwater
management design requirements. For stormwater management computations,
the reduction of site CNs based only on a weighting type analysis,
as is sometimes done for cluster type developments, is not permitted.
However, for stormwater management purposes, the CN for recharged
areas can be computed using the NRCS method for disconnected impervious
areas. The actual hydrologic process that occurs within the basin
must be stressed in all recharge situations.
These recharge requirements must be met on all sites unless
it can be demonstrated that recharge would be inappropriate. Any request
for such a waiver from these recharge requirements must be accompanied
by a supporting report certified by a qualified professional (soil
scientist, geologist, hydrogeologist, geotechnical engineer, etc.).
Developers and site design professionals are encouraged to use
a higher standard for recharge volume on sites where local site conditions
do not restrict a higher standard.
Water Quality Sensitive (WQS) developments must use an acceptable
pre-treatment BMP prior to recharge. Acceptable pre-treated BMPs for
these developments include BMPs that are based on filtering, settling,
or chemical reaction processes such as chemical coagulation.
Accounting for recharge within lined stormwater management ponds
is not permitted. However, if unlined, uncompacted ponds and/or depressed
lawn areas are used to satisfy water quality or capture volume criteria,
these areas and volumes can also be used to meet recharge requirements
as previously defined. Additional recharge volume may be credited
to these areas as long as it is demonstrated by a qualified professional
that recharge processes can naturally occur in these areas.
Finally, because this analysis is concerned with trying to adequately
represent real processes that occur within the Watershed, there will
be areas that cannot physically recharge stormwater. These areas include
exfiltration areas that are commonly found at the base of wooded hillsides
where clay pans exist, and saturation areas near major streams or
floodplains. These areas may not accept recharge during most runoff
events. These areas are exempt from recharge requirements when these
conditions are documented and certified by a qualified professional
(soil scientist, geologist, hydrogeologist, or geotechnical engineer).
In addition, stormwater management techniques relying on infiltration
techniques are not permitted in these areas.
|
The Borough Engineer may waive the recharge requirement in the
following situations:
| ||
|
•
|
The Borough Engineer may waive the recharge requirement in highly
developed areas or areas undergoing redevelopment where the Borough
Engineer has determined that forced recharge could have adverse impacts
on adjacent landowner structures, property, or municipal infrastructure.
These waivers should be limited to small land areas (generally less
than five acres in size), where the ability to place recharge beds
may be limited or may hinder redevelopment.
| |
|
•
|
The Borough Engineer may waive the recharge requirement in areas
where a qualified soils scientist or geologist has determined that
none of the site soils are suitable for recharge, or that the location
of the suitable soils is such that harm to adjoining properties could
occur as stated under item one above.
| |
|
•
|
The Borough Engineer may waive the recharge requirement in areas
where recharge cannot physically occur as documented by a qualified
soil scientist, geologist, or hydrologist. These areas include:
| |
|
•
|
Exfiltration areas commonly found at the base of wooded hillsides
where clay pans or fragipans exist; and
| |
|
•
|
Saturation areas near major streams or floodplains.
| |
|
•
|
Development and redevelopment within the Commercial District
is exempt from the Recharge requirement if there is less than 5% increase
in proposed impervious area.
| |
|
As identified above, recharge analysis and/or waiver requests
must be supported by a geotechnical report sealed by a qualified professional
(soil scientist, geologist, hydrogeologist, or geotechnical engineer).
The intent of this report will be to establish the suitability of
a particular parcel of land or area for recharge, and to identify
areas on a development site appropriate for recharge. It is recommended
that the geotechnical/soils consultant discuss the extent and approach
to the analysis with the Borough Engineer prior to initiating the
field investigation. At a minimum this report should include the following
information:
| ||
|
•
|
A description of the geotechnical site investigation performed
including the methods and procedures used;
| |
|
•
|
Data presentation;
| |
|
•
|
Analysis results including the following minimum information:
| |
|
•
|
A map identifying site areas inappropriate for recharge along
with supporting justification. In addition to illustrating topographic
features, significant geologic and hydrologic features should be identified
(rock outcrops, sinkholes, closed depressions, etc.
| |
|
•
|
Determination of the permeability coefficient for potential
recharge areas.
| |
|
•
|
Determination of the infiltration capacity of natural site soils.
| |
|
•
|
Location, depth, and permeability coefficient for any restrictive
layers identified.
| |
|
•
|
Soil uniformity.
| |
|
•
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Depth to bedrock in potential recharge areas, and a statement
reflecting the uniformity of the depth to bedrock across the site.
| |
|
•
|
A statement relating to the site's proximity to fracture zones
within the bedrock.
| |
|
•
|
Additional information deemed pertinent by the geotechnical
engineer.
| |
|
•
|
Recommendations for any special design considerations necessary
for the design of recharge systems on the site. For example, required
soil depth over bedrock, appropriate surface grades over recharge
areas, appropriate hydraulic head over recharge areas, etc.
| |
|
•
|
Justification as to why the site should be developed to a high
impervious density if the site has adverse soil and geotechnical limitations,
which prohibit the ability to induce natural recharge. Explain how
these limitations will not create the potential for undue harm to
the environment and the Spring Creek Watershed when the site is developed.
| |
|
Where it has been shown that recharge cannot be performed and
a waiver of the recharge requirements is being requested, it shall
be required that the first one inch of runoff from all new impervious
areas be treated through under-drained facilities. These facilities
may include under-drained basins, rain gardens, and infiltration trenches.
Treatment is to include use of an amended topsoil to provide filtration
of the stormwater. All under-drain outlets are to include a restrictor
plate to prevent the underdrain system from functioning as a primary
outlet.
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|
The following guidelines are provided relative to the use of
subsurface exfiltration BMP's (often incorrectly referred to as engineered
infiltration BMPs):
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|
•
|
Soils should have a minimum percolation rate of 50 min/cm for
effective operation of subsurface exfiltration BMPs. If no site soils
have percolation rates of 50 min/cm, subsurface exfiltration BMPs
should not be used.
| |
|
•
|
A minimum of 30 inches of soil must be maintained between the
bottom of a subsurface exfiltration BMP and the top of bedrock or
seasonally high groundwater table. This statement is subject to the
recommendation of a qualified Geotechnical Engineer.
| |
|
•
|
If the minimum percolation rate is not met and/or the minimum
soil depth can not be maintained on a site, recharge should be accommodated
by directing shallow sheet flow from impervious areas across surface
filter strips and/or undisturbed natural areas, or some other innovative
surface infiltration feature should be used. Limiting subsurface percolation
rates and/or depth to bedrock shall not by themselves warrant a recharge
waiver.
| |
|
In addition, since recharge is intended as a volume control,
innovative or new methods that address the significant increase in
the volume of runoff from sites having large impervious areas are
encouraged. These volume control alternatives can be used only if
they can be shown to function with the original intent through sound
engineering and science. The final determination of "original intent"
shall always be the right of the Borough Engineer.
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d.
Storm Drain Conveyance System Design. Storm drainage conveyance systems
consist of storm sewer pipes, swales, and open channels. Computational
methods for design of storm drain conveyance systems shall be as follows:
(1)
Recommended computational methods (models) for storm drain design
are based on site or watershed drainage area as follows:
|
Up to 200 acres in size
|
Rational Method
|
|
Between 200 acres and 1.5 square miles
|
HEC-1
PSRM
TR-20
|
|
Over 1.5 square miles in size
|
PSU-IV with the carbonate adjustment factor at the discretion
of the Borough Engineer
Other methods as approved by the Borough Engineer such as SWMM,
SWIRM-ROUTE, etc.
|
(2)
Rational Coefficients used are to be from Rawls et al. (1981),
PaDOT Design Manual 2-10 or using the Aron curves to convert CNs to
C. If the Aron curves are used, all CNs must be applicable to the
HSG as identified by the NRCS.
The Design Engineer may choose to use the following Rational
C coefficients without regard to soil HSG for small sites. However,
it is recommended that they be used only for storm drains up to 24
inches in diameter. The use of these conservative values shall fully
be the choice of the Design Engineer.
All impervious areas: C = 0.95
All pervious areas: C = 0.30
(3)
Storm drains shall be designed at a minimum using a ten-year
runoff event without surcharging inlets. Storm drains tributary to
a multiple site SWM facility or crossing other properties must convey,
at a minimum, the following runoff event based upon the classification
of municipal street:
|
Local, residential, residential access
|
25-year
|
|
Residential collector, collector
|
50-year
|
|
Arterial
|
100-year
|
|
Runoff events in excess of the indicated design event must be
conveyed safely downstream.
| |
(4)
Inlets on grade cannot assume a sumped condition for hydraulic
modeling (i.e., top of inlet casting set below pavement surface in
parking areas).
(5)
The Borough Engineer may require the analysis of the one-hundred-year
peak runoff rates for conveyance purposes in some instances where
regional SWM facilities are employed.
(6)
Any storm drain within State or Federal rights-of-ways or that
falls under the design criteria of any higher authority must meet
the requirements of that agency in addition to the minimum requirements
of this ordinance.
(7)
The time of concentration (Tc) can be computed by any method
which best represents the subject watershed. However, the NRCS's segmental
method is not recommended for use with drainage areas that are predominately
undeveloped and are greater than 100 acres in size. The NRCS Lag Equation
or another more appropriate method should be used under these conditions.
(8)
For any drainage area smaller than five acres in size, a Tc
of five minutes may always be assumed at the discretion of the Design
Engineer (for the post-development condition), without needing to
provide supporting documentation.
(9)
Precipitation values applicable to the entire Spring Creek Drainage
Basin are those reflected in the PaDOT's IDF curves for Region 2,
regardless if the area was formerly considered in Region 3.
(10)
Storm drain conveyance system stability (swales, open channels,
and pipe discharge aprons) shall be computed using a ten-year return
period peak runoff rate.
(11)
Storm sewers, where required by zoning and land use densities,
shall be placed under or immediately adjacent to the roadway side
of the curb, or as directed by the Borough, when parallel to the street
within the right-of-way.
(12)
When located in undedicated land, they shall be placed within
a drainage easement not less than 20 feet wide as approved by the
Borough Engineer.
(13)
The use of properly designed, graded and turfed drainage swales
is encouraged in lieu of storm sewers in commercial and industrial
areas and, where approved by the Borough Engineer, in residential
areas.
Such swales shall be designed not only to carry the required
discharge without excessive erosion, but also to increase the time
of concentration, reduce the peak discharge and velocity, and permit
the water to percolate into the soil, where appropriate.
(14)
Inlet types and inlet assemblies shall conform to PaDOT Standards
for Roadway Construction as approved by the Borough Engineer.
(a)
Inlets shall, at a minimum, be located at the lowest point of
street intersections to intercept the stormwater before it reaches
pedestrian crossing; or at sag points of vertical curves in the street
alignment which provide a natural point of ponding of surface stormwater.
(b)
Where the Borough deems it necessary because of special land
requirements, special inlets may be approved.
(c)
The interval between inlets collecting stormwater runoff shall
be determined in accordance with DM-2, Chapter 10, Section 3, "Capacity
of Waterway Areas."
In curbed sections, the maximum encroachment of water on the
roadway pavement shall not exceed half of a through traffic lane or
one inch less than the depth of curb during the ten-year design storm
of five minute duration. Inlets shall be provided to control the encroachment
of water on the pavement. When inlets are used in a storm system within
the right-of-way limits of a street in lieu of manholes, the spacing
of such inlets shall not exceed the maximum distance of 450 feet.
(15)
Accessible drainage structures shall be located on a continuous
storm sewer system at all vertical dislocations, at all locations
where a transition in storm sewer pipe sizing is required, at all
vertical and horizontal angle points exceeding 5°, and at all
points of convergence of two or more influent storm sewer mains. The
construction locations of accessible drainage structures shall be
as indicated on the land development drainage plan or area drainage
plan approved by the Borough.
(16)
When evidence available to the Borough indicates that existing
storm sewers have sufficient capacity as determined by hydrograph
summation and are accessible, the subdivider may connect their stormwater
facilities to the existing storm sewers so long as the peak rate of
discharge does not exceed the amount permitted by this ordinance.
(17)
All other storm drain design methods are to be the same as specified
in existing local ordinances.
(18)
Computational procedures other than those indicated here should
follow the methods of the Federal Highway Administration's Urban Drainage
Design Manual [Hydraulic Engineering Circular No 22. (HEC-22)].
e.
Water Quality Standards.
(1)
Water Quality Performance Standards. To minimize adverse impacts
to stream health resulting from stormwater non-point source (NPS)
pollution, standards are provided for the implementation of Water
Quality Best Management Practices (BMPs) to reduce NPS pollutant loadings
resulting from land development activities. The following performance
standards and guidelines shall be addressed at all sites where stormwater
management is required.
(a)
Site designs shall minimize the generation of stormwater runoff
through the use of low-impact design techniques.
(b)
Stormwater runoff from all land development activities should
be treated through the use of non-structural and structural BMPs to
effectively treat the adverse impacts of stormwater runoff including
NPS pollutants.
(c)
Water Quality BMPs shall be incorporated into site designs to
treat the required Water Quality volume as defined below.
(d)
The use of non-structural BMPs shall always take priority over
the use of structural BMPs. The use of innovative BMPs and low-impact
site planning is encouraged to reduce the generation of stormwater
runoff and effectively treat pollutants transported in stormwater
from the site.
(e)
The use of multiple non-structural water quality techniques
along with new, emerging, and innovative techniques is encouraged
to improve the quality of stormwater runoff to receiving areas and
reduce and/or eliminate the need for structural BMPs. The Borough
Engineer should be consulted to clarify the design concept for meeting
or exceeding the intent of this section.
(f)
Where non-structural BMPs are unable to effectively treat all
of the stormwater runoff generated from land development activities,
structural BMPs shall be designed to capture and treat the computed
water quality volume (WQv).
(g)
The priority areas to be treated with BMPs are streets, parking
lots, driveways, and roof areas.
(h)
Due to the karst nature of the Watershed, stormwater discharges
from water quality sensitive developments and discharges to sensitive
wellhead protection areas (defined in Appendix B, Exhibit-1 in the
Spring Creek Watershed Action 167 Stormwater Management Plan) will
require special consideration. In these instances the applicant shall
provide water quality pre-treatment (use of a filtering BMP and/or
special structural design features) to prevent the discharge of stormwater
contaminants to groundwater resources. In addition, hydrogeologic
studies may be required to document potential karst related impacts.
(i)
Prior to stormwater management and water quality design, applicants
should consult with the Borough Engineer to verify stormwater quality
criteria and present proposed features and concepts for the treatment
of stormwater runoff. Following this meeting, the Borough Engineer
shall define any needed support studies or documentation.
(2)
Water Quality Volume (WQv). The required water quality volume
that must be treated for non-sensitive areas underlain by carbonate
rock (see exhibits in Appendix B) within the Spring Creek Basin shall
be computed as:
|
WQdepth = 0.25+(0.012)2.9(0.044(SIA))
WQv = WQdepth(A)/12
|
|
Where:
| |||
|
WQv
|
=
|
water quality volume in acre-feet
| |
|
WQdepth
|
=
|
depth in inches that must be captured for impervious areas
| |
|
SIA
|
=
|
percent of site impervious area (all paved areas and roof with
asphalt-based roofs)
| |
|
A
|
=
|
total of all paved areas and asphalt-based roofs on site in
acres
| |
|
The required water quality volume that must be treated for any
WQS development, on sites in sensitive areas underlain by carbonate
rock, and all areas not underlain by carbonate rock is to be computed
within the entire Spring Creek Basin as:
|
|
WQdepth = the larger of 0.5 inches or
0.25+(0.012)2.9(0.044(SIA))
|
|
WQv = WQdepth(A)/12
|
|
Where:
| |||
|
WQv
|
=
|
water quality volume in acre-feet
| |
|
WQdepth
|
=
|
depth in inches that must be captured for impervious areas
| |
|
SIA
|
=
|
percent of site impervious area (all paved areas and roof with
asphalt-based roofs)
| |
|
A
|
=
|
total of all paved areas and asphalt-based roofs on site in
acres
| |
|
For designs in which the final roof material is unknown, the
Design Engineer must assume an asphalt-based roof.
|
|
The water quality volume must be captured and treated through
a water quality BMP over an extended period of time as per the specific
requirements of each structure. Credits to reduce the effective impervious
area are applicable as presented in Chapter 4 of the Stormwater Management
Plan.
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(3)
Water Quality Credits. Due to the karst nature of the Spring
Creek Basin, the non-structural water quality credits and techniques
identified below may be limited for suitability and use based on development
type and location. These limitations for use are specified in the
restrictions section for each credit. The Borough Engineer may require
additional documentation or investigation prior to use of each specific
credit to reduce the risks of sinkhole development or groundwater
contamination for sensitive areas and development types. No area may
be double counted for use with credits. The combined credits of natural
area conservation and vegetated filter strips are limited to 50% of
the site's impervious area. The drainage way credit is limited to
50% of the site's impervious area. The drainage way protection credit
is limited to 50% of the site's impervious area. The maximum total
water quality credit for any site may therefore be 100% of the site's
impervious area.
|
Non-Structural Technique
|
Water Quality Credit
|
|---|---|
|
Drainage-way Protection (DWP)
|
Subtract Drainage-way Protection Areas from impervious site
area in WQv computation.
|
|
Natural Area Conservation (NAC)
|
Subtract Conserved Natural Areas from impervious site area in
WQv computation.
|
|
Filter/Buffer Area
|
Subtract impervious areas discharged over pervious areas from
impervious site area in WQv computation.
|
(4)
Drainage-way Protection. A water quality credit is given for
the protection of natural drainage-ways on a development site. Natural
karst drainage-ways within the Spring Creek Watershed often do not
exhibit a defined channel bed and banks. More often, these drainage-ways
appear as wide, shallow parabolic swales. These drainage-ways are
an integral part of the natural drainage system, and often exhibit
significant infiltration capacity. Protection of these drainage-ways
is critically important to the health of the watershed.
The drainage-way protection (DWP) area is defined as an area
centered on the drainage-way and having a maximum width of 300 feet.
The Borough Engineer may modify the defined maximum width in cases
where natural land forms define an appropriate alternate width.
The impervious area used in the WQv equation
for the development site may be reduced by twice the area of the preserved
drainage-way (2 to 1 ratio).
(a)
Restrictions on the Credit:
(i)
Drainage-way protection areas must remain in an
undisturbed condition during and after construction activities. There
can be no construction activity within these areas including temporary
access roads or storage of equipment or materials. Temporary access
for the construction of utilities crossing this protection area may
be permitted at the Borough Engineer's discretion. However, the alignment
of any such crossing must be perpendicular to the drainageway.
(ii)
These areas should be placed in a conservation
easement or be permanently preserved through a similarly enforceable
agreement with the Borough of State College.
(iii)
The limits of the undisturbed DWP area and conservation
easement must be shown on all construction plans.
(iv)
The DWP area must be located on the development
site.
(v)
The maximum total DWPA credit is 100% of the site
impervious area.
(vi)
Water quality credits are not permitted for Water
Quality Sensitive (WQS) developments.
(5)
Natural Area Conservation. A water quality credit is given for
natural areas that are conserved at the development site, thereby
maintaining pre-development water quality characteristics. The impervious
area used in the WQv equation for the development
site may be reduced by the natural area conserved in the water quality
volume computations. Natural area conservation is different than vegetated
filter strip/recharge area and drainage way protection in that in
some cases surface runoff may never be directed over the natural area
(i.e., if upslope wooded areas are conserved).
(a)
Restrictions on the Credit:
(i)
Natural areas must remain in an undisturbed condition
during and after construction activities. Temporary incidental land
disturbance activities associated with utility construction may be
permitted within the conservation area.
(ii)
These areas should be placed in a conservation
easement or similarly enforceable agreement with the Borough of State
College.
(iii)
The limits of the undisturbed area and conservation
easement must be shown on all construction plans.
(iv)
The area must be located on the development site.
(v)
Water quality credits are not permitted for Water
Quality Sensitive (WQS) developments.
(vi)
The maximum total NAC credit is 50% of the site
impervious area. However, the combination of NAC VFRS is also 50%.
(b)
Sensitive Area and Development Restrictions:
(6)
Filter/Buffer Area. A water quality credit is given when stormwater
runoff is effectively treated via a filter/buffer area or strip. A
filter/buffer area is a vegetated boundary characterized by uniform
mild slopes. Filter strips may be forested or vegetated with turf
grass. Effective treatment is achieved when impervious area runoff
is directed as sheet flow across vegetative filter or buffer areas
(i.e., concentrated flow discharged to a filter strip does not meet
water quality reduction criteria).
The area draining via overland sheet flow to an undisturbed,
natural, vegetated filter strip (natural unmaintained meadow or forested
area) can be subtracted from the site impervious area (IA) on a 1:1
area ratio in the water quality volume computation. Impervious areas
draining across constructed (disturbed or regarded) pervious areas
can be subtracted from the site impervious area (IA) on a 1:1/2 area
ratio in the water quality volume computation.
(a)
Restrictions on the Credit:
(i)
The maximum impervious area that can be included
in this credit, shall be computed as follows:
|
IAc = WIA LIA
|
|
Where:
| |||
|
IAc
|
=
|
Impervious area recharge credit (L2).
| |
|
LIA
|
=
|
Length of impervious area measured perpendicular to the sheet
flow direction (L).
| |
|
WIA
|
=
|
Width of impervious area (L). Maximum width permitted for credit
is the smaller of 100 feet or twice the width of the vegetated filter
strip.
| |
(ii)
To qualify for a water quality credit, natural
and constructed filter areas or strips must meet the same restrictions
identified for natural or constructed recharge areas with regard to
width, length, slope, tributary drainage length, and construction.
These restrictions are presented in Chapter 3 in the Spring Creek
Watershed Action 167 Stormwater Management Plan.
(iii)
Runoff shall enter the filter/buffer strip as
overland sheet flow.
(iv)
Filter/buffer areas shall remain undisturbed/unmanaged
other than to remove accumulated trash and debris.
(v)
Water quality credits are not permitted for Water
Quality Sensitive (WQS) developments.
(vi)
The maximum total water quality credit for vegetative
filter/buffer areas is 50% of the site impervious area. However, the
combination of NAC and filter/buffer areas is also 50%.
(7)
Comments Related to Water Quality Credits. Concurrence of the
Borough Engineer is required prior to the use of all water quality
credits for the reduction of the water quality treatment volume. The
Borough Engineer may approve the use of additional credits based upon
sufficient documentation regarding suitability for sensitive development
types and areas, pollutant removal effectiveness, and maintenance
criteria. Multiple water quality credits cannot be claimed for the
identical area of the site (i.e., a stream buffer credit and disconnecting
roof recharge area cannot both be claimed for the same area).
Additional impervious coverage reduction using low impact development
techniques (development practices which reduce the impact of urban
runoff such as narrower residential road sections, smaller culs-de-sac,
smaller parking stalls, smaller building set-backs to reduce driveway
lengths, etc.) will also reduce the required water quality treatment
volume. Many of these techniques require prior approval by the Borough
before implementation into land development design.
[Ord. 1741, 3/17/2003, Section 115; amended by Ord. 1774,
3/2/2004, Section 4; Ord. 2049, 10/6/2014]
a.
Whenever the vegetation and topography are to be disturbed, such activity must be in conformance with Chapter 102, Title 25, Rules and Regulations, Part I, Commonwealth of Pennsylvania, Department of Environmental Protection (DEP), Subpart C, Protection of Natural Resources, Article II, Water Resources, Chapter 102, "Erosion Control", and in accordance with the Centre County Conservation District and the standards and specifications of the appropriate municipal government.
b.
The Centre County Conservation District has been delegated the authority
by the PA DEP to administer the Erosion and Sediment Control (E&SC)
Program in Centre County. It shall be the responsibility of the land
developer to submit the E&SC Plan, application and other necessary
material to the Conservation District for review and approval. A copy
of the transmittal letter, plan, narrative and other necessary material
shall be provided to the Borough.
c.
The PA DEP has regulations that require an E&SC Plan for any
earth disturbance activity of 5,000 square feet or more under 25 Pa.
Code § 102.4(b).
d.
In addition, under 25 Pa. Code Chapter 92, a PA DEP "NPDES Construction
Activities" permit is required for any earth disturbance of one acre
or more with a point source discharge to surface waters or the Borough's
storm sewer system, or five acres or more regardless of the planned
runoff (herein collectively referred to as "Regulated Earth Disturbance
Activities"). This includes earth disturbance on any portion or, part
of, or during any stage of, a larger common plan of development.
e.
No regulated earth disturbance activities within the Borough shall
commence until approval is obtained from the Centre County Conservation
District and with notice of approval given to the Borough of an E&SC
Plan for construction activities.
f.
Comments shall be received and the E&SC Plan approval obtained
from the Centre County Conservation District prior to issuance of
any zoning permits for construction within the area covered by the
SWM Site Plan.
g.
Evidence of any necessary permit(s) for regulated earth disturbance activities from the appropriate PA DEP regional office or the Centre County Conservation District must be provided to the Borough. The issuance of an NPDES Construction Permit or permit coverage under the state-wide general permit (PAG-2) satisfies the requirements in Subsection (e).
h.
Additional erosion and sediment control design standards and criteria
that must be applied where recharge or water quality BMPs are proposed
include the following:
(1)
Areas proposed for these BMPs shall be protected from sedimentation
and compaction during the construction phase, so as to maintain their
maximum infiltration capacity.
(2)
These BMPs shall not be constructed nor receive runoff until
the entire contributory drainage area to the BMP has received final
stabilization.
(3)
Adequate erosion protection shall be provided along all open
channels and at all points of discharge.
i.
A copy of the E&SC Plan and any permit, as required by PA DEP
regulations shall be available at the project site at all times.
[Ord. 1741, 3/17/2003, Section 116; amended by Ord. 2049,
10/6/2014]
The use of sinkholes for stormwater management must be carefully
planned, because discharging runoff directly into existing sinkholes
is not an engineered stormwater solution. Aside from potential water
quality effects, cover collapse sinkholes that exist throughout the
watershed can be unstable, and it should be assumed that they could
stop taking water at any time. Numerous sinkholes throughout the region
already flood during larger runoff events. Nonetheless, in the watershed
there are large drainage areas that completely drain to existing sinkholes
and all upslope development tributary to them cannot be realistically
stopped. Therefore the following sections have been developed.
a.
Stormwater from roadways, parking lots, storm sewers, roof drains,
or other concentrated runoff paths shall not be discharged directly
into sinkholes without prior filtration in accordance with § 14-218b,
below.
b.
Sinkholes capable of absorbing substantial amounts of stormwater
shall be protected by diverting such runoff around the sinkhole (refer
to § 14-218f) or, upon recommended approval of the Borough
Engineer, by planting and maintaining a dense filter path of suitable
vegetative material in such a manner and location to disperse and
slow the runoff to a sheet flow condition to promote the maximum possible
filtration and sedimentation of impurities.
The filter path must be at least 100 feet in length and 20 feet
in width. Ten-foot wide filter paths are acceptable if land slope
is less than 2%.
Filter paths shall be designed and installed so that they filter
sheet flow rather than concentrated flow. If concentrated flow occurs,
grading and shaping or the use of best management practices such as
grass waterways or drop structures may be required.
Sedimentation basins designed to PA DEP Chapter 102 Standards
or permanent stormwater storage criteria, whichever is larger, and
proposed vegetative filter paths, in conjunction with temporary stone
filter check dams, shall be installed prior to subdivision or land
development construction activities, where sinkholes are used to accept
stormwater discharges.
c.
If increased runoff is to be discharged into a sinkhole, even in
filtered conditions, a hydrogeologic assessment of the effects of
such runoff on the increased risk of land subsidence and adverse impacts
to existing sinkhole floodplains and groundwater quality shall be
made by a qualified professional and submitted with the stormwater
management plan. Such discharge shall be prohibited if the Borough
Engineer determines that such poses a hazard to life, property or
groundwater resources.
d.
All sinkholes shall be posted by permanent on-site notices clearly
visible at the sinkhole prohibiting any disposal of refuse, rubbish,
hazardous wastes, organic matter or soil into the sinkhole. Rock fill
may be permitted in the sinkhole for the purpose of preventing dumping
of said materials.
e.
To protect sensitive Karst areas, the Borough Engineer may require
basins to contain an impervious liner. The liner may be of the impervious
membrane type, placed in accordance with the manufacturer's recommendations,
or may be constructed by mixing bentonite, or an approved alternative,
with existing soil available at the site as approved by the Borough
Engineer.
f.
If it is determined that runoff from upslope developing areas should
be diverted around a sinkhole due to existing problems, the Borough
Engineer may require additional upstream volume controls as required
to protect downstream areas.
[Ord. 1741, 3/17/2003, Section 117; amended by Ord. 2049,
10/6/2014]
Materials, Workmanship and Methods: All materials, workmanship
and methods of work shall comply at a minimum with the Pennsylvania
Department of Transportation Form 408 specifications, as accepted
and commonly used by the Borough of State College, and shall be considered
to be incorporated into this article as if copied in full. In the
event a conflict arises between the requirements of this article and
the Form 408 Specifications, the Borough Engineer shall resolve the
difference, and his opinion shall be binding.
a.
General.
(1)
Facilities in State Rights-of-Way. Any stormwater facility located
on State highway rights-of-way shall be subject to approval by PaDOT.
Any stormwater facility that discharges directly onto state highway
rights-of-way shall be subject to review by the PaDOT.
(2)
Water Obstructions. Any facilities that constitute water obstructions
(e.g., culverts, bridges, outfalls, or stream enclosures), and any
work involving wetlands as directed in PA DEP Chapter 105 regulations
(as amended or replaced from time-to-time by PA DEP), shall be designed
in accordance with Chapter 105 and will require a permit from PA DEP.
Any other drainage conveyance facility that does not fall under Chapter
105 regulations must be able to convey, without damage to the drainage
structure or roadway, runoff from the twenty-five-year design storm
with a minimum of 1.0 foot of freeboard measured below the lowest
point along the top of the roadway. Roadway crossings located within
designated floodplain areas must be able to convey runoff from a one-hundred-year
design storm with a minimum of 1.0 foot of freeboard measured below
the lowest point along the top of roadway. Any facility that constitutes
a dam as defined in PA DEP Chapter 105 regulations may require a permit
under dam safety regulations. Any facility located within a PaDOT
right-of-way must meet PaDOT minimum design standards and permit submission
requirements.
(3)
Conveyance Facilities. Any drainage conveyance facility and/or
channel that do not fall under Chapter 105 Regulations, must be able
to convey, without damage to the drainage structure or roadway, runoff
from the return period design storm as specified in § 14-216d(3).
Conveyance facilities to or exiting from stormwater management facilities
(i.e., detention basins) shall be designed to convey the design flow
to or from that structure. Roadway crossings located within designated
floodplain areas must be able to convey runoff from a one-hundred-year
design storm. Any facility located within a PaDOT right-of-way must
meet PaDOT minimum design standards and permit submission requirements.
b.
Stormwater Basin Design Considerations. Stormwater management basins
for the control of stormwater peak discharges shall meet the following
minimum requirements:
(1)
The design of all facilities over limestone formations shall
include measures to prevent groundwater contamination and where required,
sinkhole formation. Soils used for the construction of basins shall
have moderate to low erodibility factors (i.e., "K" factors of 0.32
or less). Any basin greater than four feet in height, measured from
the top of berm to the downslope toe of the abutment, must also contain:
(2)
Energy dissipaters and/or level spreaders shall be installed
at points where pipes or drainageways discharge to or from basins.
Generally, outlet pipes designed to carry the predevelopment, one-year
storm flow will be permitted to discharge to a stream with only an
energy dissipater. Discharges to drainage swales shall be spread with
a level spreader or piped to an acceptable point.
(3)
Outlet structures:
(a)
Outlet structures within detention/retention basins shall be
constructed of reinforced concrete or an approved alternate. With
the exception of those openings designed to carry perennial stream
flows, design openings shall have childproof, non-clogging trash racks
over all openings nine inches or greater in any dimension. Outlet
aprons shall be designed and shall extend at a minimum to the toe
of the basin slope. Where spillways will be used to control peak discharges
in excess of the ten-year storm, the control weirs shall be constructed
to withstand the pressures of impounded waters and convey flows at
computed outlet velocities without erosion.
(b)
All metal risers, where approved for use, shall be suitably
coated to prevent corrosion. A trash rack or similar appurtenance
shall be provided to prevent debris from entering the riser. All metal
risers shall have a concrete base attached with a watertight connection.
The base shall be sufficient weight to prevent flotation of the riser.
An anti-vortex device, consisting of a thin vertical plate normal
to the basin berm, shall be provided on the top of all metal risers.
(4)
Emergency Spillway.
(a)
Any stormwater management facility (i.e., detention basin) designed
to store runoff and requiring a berm or earthen embankment required
or regulated by this ordinance shall be designed to provide an emergency
spillway to handle flow up to and including the one-hundred-year post-development
conditions. The height of embankment must be set as to provide a minimum
one foot of freeboard above the elevation required to safely pass
the one-hundred-year post-development inflow. Should any stormwater
management facility require a dam safety permit under PA DEP Chapter
105, the facility shall be designed in accordance with Chapter 105
and meet the regulations of Chapter 105 concerning dam safety which
may be required to pass storms larger than a one-hundred-year event.
Any underground stormwater management facility (pipe storage
systems) must have a method to bypass flows higher than the required
design (up to a one-hundred-year post-development inflow) without
structural failure or causing downstream harm or safety risks.
Any stormwater management facility that has a paved roadway
as the lower berm, and therefore cannot provide a traditional berm
emergency spillway, is not required to provide 0.5 feet of freeboard
above the elevation required to safely pass the one-hundred-year post-development
inflow, but is required to show that the design is stable and no significant
undermining, scour or erosion will occur.
(b)
Emergency spillways shall be constructed of reinforced concrete,
vegetated earth, or riprap in accordance with generally accepted engineering
practices. All emergency spillways shall be constructed so that the
detention basin berm is protected against erosion. The minimum capacity
of all emergency spillways shall be the peak flow rate from the one-hundred-year
design storm. The dimensions of the emergency spillways can be determined
from the Centre County Erosion and Sediment Control Handbook. Emergency
spillways shall extend along the upstream and downstream berm embankment
slopes. Protection should be provided on the upstream embankment a
minimum of three feet below the spillway crest elevation. Protection
at the downstream slope of the spillway shall, as a minimum, extend
to the toe of the berm embankment. The emergency spillway shall not
be located on or discharge over uncompacted earthen fill and/or easily
erodible material.
(c)
Rock-filled gabions may be used where combination berm and emergency
spillway structures are required to prevent concentrated flows. The
Borough Engineer may require the use of open concrete lattice blocks,
stone riprap, or concrete spillways when slopes would exceed four
feet horizontal to one-foot vertical and spillway velocities might
exceed Soil Conservation Service standards for the particular soils
involved.
(5)
Antiseep Collars. Antiseep collars shall be installed around
the principal pipe barrel within the normal saturation zone of the
detention basin berms. The antiseep collars and their connections
to the pipe barrel shall be watertight. The antiseep collars shall
extend a minimum of two feet beyond the outside of the principal pipe
barrel. The maximum spacing between collars shall be 14 times the
minimum projection of the collar measured perpendicular to the pipe.
(6)
Slope of Detention Basin Embankment. The top or toe of any slope
shall be located a minimum of 10 feet from any property line. Whenever
possible the side slopes and basin shape shall be amenable to the
natural topography. Straight side slopes and rectangular basins shall
be avoided whenever possible.
(a)
Exterior slopes of compacted soil shall not exceed three feet
horizontal to one-foot vertical, and may be further reduced if the
soil has unstable characteristics.
(b)
Interior slopes of the basin shall not exceed three feet horizontal
to one-foot vertical, except with approval of the Borough of State
College.
(7)
Width of Berm. The minimum top width of detention basin berms
shall be 10 feet.
(8)
Slope of Basin Bottom. In order to ensure proper drainage of
the detention basin, a minimum grade of 2% shall be maintained for
all basins used exclusively for peak runoff control. Water quality
or recharge basins with filtration systems incorporated into them
may have a minimum grade of 1/2 (0.5%).
(9)
The lowest floor elevation of any structure constructed adjacent
to a detention or retention basin or other stormwater facility shall
be two feet above the highest water surface elevation. The distance
between any residential or nonresidential structure and any swale
or open channel stormwater facility shall be a minimum of 25 feet.
(10)
Landscaping and planting specifications must be provided for
all stormwater management basins and be specific for each type of
basin.
(a)
A minimum of six inches of topsoil material shall be placed
on all areas affected by the basin construction (bottom of basin,
side slopes, top of berm, etc.) and all other vegetative areas, unless
waived by Borough Engineer. The material must meet the minimum requirements
of the PaDOT Form 408, specifications, as amended.
(11)
Basins should be lined with impervious liners only in areas
with a high risk of sinkhole formation or potential groundwater contamination
as determined by a geotechnical engineer. However, where a liner is
deemed necessary or appropriate, the use of controlled, compacted
natural clay liners, for SWM basins should be considered. Locally
available clay, when properly installed, can provide near impervious
conditions (approximately E-6 cm/s or less). Some of the advantages
of using controlled, compacted, natural clay soil liners are:
(a)
Can offer better long-term solution as a basin liner versus
geosynthetics because of greater thickness and the ability to withstand
settlement;
(b)
Can be constructed to allow relatively uniform leakage rates
to facilitate ground-water recharge but not to an excessive degree
that overloads karst bedrock;
(c)
When properly constructed in two or more eight- to ten-inch
thick lifts, rapid movement of surface water through the clay liner
is eliminated (rapid leaks can occur in geosynthetic lined basins
due to poor seaming, punctures, or other factors);
(d)
Cleaning/maintenance of clay-lined stormwater basins will be
easier/safer versus geosynthetic liners which could easily be damaged
during maintenance operations; and
(e)
The abundance of clayey soils (derived from limestone residuum)
within the Spring Creek Watershed can provide adequate, cost effective,
soil resources for construction of clay liner systems at most development
projects.
However, the installation of any low permeability clay liner
system needs to be carefully controlled and the designer needs to
ensure that specifications meet standards to ensure integrity.
c.
Construction of Basins.
(1)
Basins shall be installed prior to or concurrent with any earth
moving or land disturbances, which they will serve. The phasing of
their construction shall be noted in the narrative and on the plan.
Basins that include water quality or recharge components shall have
those components installed in such a manner as to not disturb or diminish
their effectiveness.
(2)
Construction specifications in accordance with the minimum criteria
of the Borough of State College must be provided for all embankments
pursuant to Section B.1.b of Section 118.
(3)
Compaction test reports shall be kept on file at the site and
be subject to review at all times with copies being forwarded to the
Borough Engineer upon request.
(4)
When rock is encountered during the excavation of a pond, it
shall be removed to an elevation of at least 12 inches below the proposed
basin floor (for a manufactured liner, 24 to 30 inches). All exposed
cracks and fissures are to be structurally filled.
(5)
Temporary and permanent grasses or stabilization measures shall
be established on the sides and base of all earthen basins within
15 days of construction.
(6)
A quality control program is critical for embankment fills.
Therefore, whenever embankment fill material in excess of three feet
is to be used, each layer of compacted fill shall be tested to determine
its density per ASTM D2922. The density of each layer shall be 90%
of a Standard Proctor analysis for ASTM 698.
d.
Construction Inspection. Inspections may be conducted by the Borough
Engineer during the construction of the stormwater management basin
and facilities. Such inspections do not constitute approval of construction
methods or materials. The design professional shall perform site inspections
as may be necessary to ensure that all stormwater management facilities
are constructed in accordance with the approved plans.
e.
Special Use Basins.
(1)
The design and construction of multiple use stormwater detention
facilities are strongly encouraged. In addition to stormwater management,
facilities should, where appropriate, allow for recreational uses
including: ball fields, play areas, picnic grounds, etc. Provision
for parking facilities within basins and permanent wet ponds with
stormwater management capabilities may also be appropriate. Prior
approval and consultation with the Borough are required before design.
Multiple use basins should be constructed so that potentially dangerous
conditions are not created.
Water quality basins or recharge basins that are designed for
a slow release of water or other extended detention ponds are not
permitted for recreational uses, unless the ponded areas are clearly
separated and secure.
(2)
Multiple Development Basins. Stormwater management facilities
designed to serve more than one property or development in the same
watershed are encouraged. Staged construction of existing or proposed
multiple-use detention facilities by several developers in conjunction
with watershed development is encouraged. Each developer shall be
responsible for the incremental increase in runoff generated by the
respective development and incremental construction improvements necessary
for the overall detention facility. Prior approval and consultation
with the Borough is required before design of such facilities.
(3)
Alternative Detention Facilities. Alternative stormwater detention
facilities including rooftop, subsurface basins or tanks and in-pipe
detention storage, or other approved alternative designs are permitted
as determined by the Borough Engineer.
[Ord. 1741, 3/17/2003, Section 118; amended by Ord. 2049,
10/6/2014]
Stormwater management facilities located outside of existing
or proposed rights-of-way shall be located within and accessible by
easements as follows:
a.
Drainage Easements. Where a tract is traversed by a watercourse,
drainage-way, channel or stream, there shall be provided a drainage
easement paralleling the line of such watercourse, drainage-way, channel
or stream. The width of the drainage easement will be adequate to
preserve the unimpeded flow of natural drainage in the one-hundred-year
floodplain, in accordance with computed top widths for water surface
elevations determined under Section 116.a(3).
b.
Access Easements. Where proposed stormwater management facilities
are not adjacent to proposed or existing public rights-of-way or are
not accessible due to physical constraints, as determined by the Borough
Engineer, a twenty-foot wide passable access easement specifying rights
of entry shall be provided. Access easements shall provide for vehicle
ingress and egress on grades of less than 10% for carrying out inspection
or maintenance activities.
c.
Maintenance Easements. A maintenance easement shall be provided which
encompasses the stormwater facility and appurtenances and provides
for access for maintenance purposes. The maintenance easement must
be located outside of one-hundred-year surface elevation and the stormwater
facility and appurtenances.
d.
Easements shall stipulate that no trees, shrubs, structures, excavation
or fill be placed and no regrading be performed within the area of
the easement without written approval from the Borough upon review
by the Borough Engineer. Upon approval of the Borough Engineer, such
landscaping may be placed in maintenance easements, provided it does
not impede access.
e.
Whenever practicable, easements shall be parallel with and conjunctive
to property lines of the subdivision.
f.
All easement agreements shall be recorded with a reference to the
recorded easement indicated on the site plan. The format and content
of the easement agreement shall be reviewed and approved by the Borough
Engineer and Solicitor. (See § 14-232.)
g.
When stormwater conveyance pipes or channels are located in undedicated
land, they shall be placed within a drainage easement not less than
20 feet wide as approved by the Borough Engineer.
[Ord. 1741, 3/17/2003, Section 119; amended by Ord. 2049,
10/6/2014]
From and after the date of enactment of this ordinance, a stormwater
management site plan and other information specified herein shall
be submitted to the Borough of State College for all lands subdivided
or for which land development plans are prepared after the enactment
of this ordinance, unless the project qualifies for an exemption as
noted in § 14-210. A stormwater management site plan and
other information specified herein shall be submitted at the same
time and together with submission of a preliminary subdivision or
final land development plan, along with a completed checklist supplied
by the Borough indicating the items contained within the submission.
Such plans and information shall be considered part of said
zoning and subdivision documents and shall be reviewed in accordance
with procedures established thereunder. Preliminary approval or final
approval of a subdivision or land development plan, or the issuance
of a zoning permit, shall be contingent upon submission of a stormwater
management site plan and other materials specified herein, and approval
of the stormwater management plan in accordance with provisions of
this ordinance.
All stormwater management site plans shall be submitted to the
Borough for review and comment. Such review shall include a statement
by the Borough Engineer specifying the provisions of this ordinance,
which have not been met by the plan as submitted.
Once a stormwater management site plan has been approved together
with a subdivision or land development plan approval, or together
with the issuance of a zoning permit, said stormwater management site
plan shall be valid only for the subdivision, land development, or
zoning permit approved. Any further development on the lot or lots
requiring a revision of the approved plan or other construction or
activities as defined by State College Borough Zoning or Subdivision
and Land Development Regulations shall require the submission of a
new, amended, or revised stormwater management site plan and other
information specified herein.
[Ord. 1741, 3/17/2003, Section 120; amended by Ord. 2049,
10/6/2014]
The SWM Site Plan shall consist of all applicable calculations,
maps, and plans. A note on the maps shall refer to the associated
computations and erosion and sediment pollution control plan by title
and date. The cover sheet of the computations and erosion and sediment
pollution control plan shall refer to the associated maps by title
and date. All SWM Site Plan materials shall be submitted to the Borough
in a format that is clear, concise, legible, neat, and well organized;
otherwise, the SWM Site Plan shall be disapproved and returned to
the applicant.
Said plan shall be prepared by a registered professional land
surveyor, qualified geologist, landscape architect, architect, or
engineer licensed in the State of Pennsylvania, with said preparer's
seal and registration number affixed to the plan.
The following items shall be included in the SWM Site Plan:
a.
Stormwater Management Report.
(1)
General description of project, including address of project
site.
(2)
General description of permanent stormwater management techniques,
including construction specifications and materials to be used for
stormwater management facilities.
(3)
Complete hydrologic, hydraulic, and structural computations
for all stormwater management facilities.
(4)
A written maintenance plan for all stormwater features including
detention facilities and other stormwater management elements.
(5)
Identification of ownership and maintenance responsibility for
all permanent stormwater management facilities.
(6)
The stormwater management report must include a narrative which
clearly discusses the project and summary tables which, at a minimum,
provides the following information:
(a)
Narrative:
(i)
The overall stormwater management concept;
(ii)
The expected project schedule;
(iii)
Location map;
(iv)
Total site area, pre- and post-, which must be
equal or have an explanation as to why it is not;
(v)
Total site impervious area;
(vi)
Total off-site areas;
(vii)
Number of stormwater management facilities (ponds),
if applicable;
(viii)
Type of development;
(ix)
Pre-development land use;
(x)
Whether site is underlain by carbonate geology;
(xi)
Whether site is a water quality sensitive (WQS)
development;
(xii)
Whether site is in a defined sensitive area;
(xiii)
Types of water quality and recharge systems
used, if applicable;
(xiv)
Other pertinent information, as required.
(b)
Summary Tables.
(i)
Pre-development:
- Hydrologic soil group (HSG) assumptions, curve numbers, (CN)
- Computation of average slope, hydraulic length, computed time
of concentration
- Required peak rate of runoff
(ii)
Post-development:
- Undetained areas, areas to ponds
- Land use for each subarea
- Hydrologic soil group (HSG) assumptions, curve numbers (CN)
- Time of concentration computed for each subarea
- Post-development peak rate of runoff routed to ponds and out
- Pond maximum return period design data including: maximum
water surface elevation, berm elevation, and emergency spillway elevation
- Water quality depth and volume requirements
- Recharge volume requirements
- Morphology requirements
- Capture volumes required
(7)
Reports that do not clearly indicate the above information may
be rejected for review by the Borough Engineer or representative and
will be returned to the applicant.
b.
Plans for tracts of less than 20 acres shall be drawn at a scale
of one inch equals no more than 50 feet; for tracts of 20 acres or
more, plans shall be drawn at a scale of one inch equals no more than
100 feet. Plans shall be submitted on the following sheet sizes: 18
feet by 24 inches, 24 inches by 36 inches, or 36 inches by 42 inches.
All lettering shall be drawn to a size to be legible if the plans
are reduced to half size. All sheets comprising a submission shall
be on one size.
The following information, unless specifically exempted in writing
by the Borough Engineer, must be shown on the plans, prepared in a
form which meets the requirements for recording in the Office of the
Recorder of Deeds of Centre County, Pennsylvania. The contents of
the map(s) shall include, but not be limited to:
(1)
The name of the development, the name and address of the owner
of the property, and the name of the individual or firm preparing
the plan.
(2)
The date of submission and revision.
(3)
The location of the project relative to highways, municipalities
or other identifiable landmarks.
(4)
Existing contours at intervals of one foot. In areas of steep
slopes (greater than 15%), five-foot contour intervals may be used.
(5)
Existing streams, lakes, ponds, or other bodies of water within
the project area.
(6)
Other physical features including flood hazard boundaries, sinkholes,
closed depressions, wetlands, streams, existing drainage courses,
areas of natural vegetation to be preserved, and the total extent
of the upstream area draining through the site. In Addition, any areas
necessary to determine downstream impacts, where required for proposed
stormwater management facilities must be shown.
(7)
The locations of all existing and proposed utilities, sanitary
sewers, and water lines within 20 feet of property lines.
(8)
An overlay showing soil names and boundaries, including rock
outcrops.
(9)
Total area of impervious surfaces proposed.
(10)
Proposed structures, roads, paved areas, and buildings.
(11)
Final contours at intervals of one foot. In areas of steep slopes
(greater than 15%), five-foot contour intervals may be used.
(12)
A graphic and written scale.
(13)
A North arrow.
(14)
The total tract boundary and size with distances marked to the
nearest foot and bearings to the nearest degree.
(15)
Existing and proposed land use(s).
(16)
A key map showing all existing man-made features beyond the
property boundary that would be affected by the project and the extent
of the watershed or sub-area that drains through the project site.
(17)
Horizontal and vertical profiles of all open channels, including
hydraulic capacity.
(18)
Overland drainage paths.
(19)
Access easements around all stormwater management facilities
that would provide ingress to and egress from a public right-of-way.
(20)
A note on the plan indicating the location and responsibility
for maintenance of stormwater management facilities that would be
located off-site. All off-site facilities shall meet the performance
standards and design criteria specified in this ordinance.
(21)
A construction detail of any improvements made to sinkholes
and the location of all notes to be posted, as specified in this ordinance.
(22)
Complete drainage systems for the site, including details for
construction. All existing drainage features, which are to be incorporated
in the design, shall be so identified. If the site is to be developed
in stages, a general drainage plan for the entire site shall be presented
with the first stage and appropriate development stages for the drainage
system shall be indicated.
(23)
Location and selected plan material used for vegetative filter
paths to sinkholes, and the location of all notices to be posted.
(24)
A statement, signed by the landowner, acknowledging the stormwater
management system to be a permanent fixture that can be altered or
removed only after approval of a revised plan by the Borough of State
College.
(25)
A note indicating that As-Built drawings in electronic format
in accordance with State College Zoning Requirements will be provided
by the Developer for all stormwater facilities prior to occupancy,
or the release of the surety bond.
(26)
The following signature block for the registered professional
preparing the Stormwater Management Site Plan: "I, __________, hereby
certify that the Stormwater Management Site Plan meets all design
standards and criteria of the State College Borough Stormwater Management
Ordinance."
(27)
The following signature block for the Borough Engineer reviewing
the Stormwater Management Site Plan: "I, __________, have reviewed
this Stormwater Management Site Plan in accordance with the Design
Standards and Criteria of the State College Borough Stormwater Management
Ordinance."
(28)
The location of all erosion and sedimentation control facilities.
c.
Supplemental Information:
(1)
A soil erosion and sediment pollution control plan, where applicable,
including all reviews and approvals, as required by PA DEP.
(2)
Soils investigation report, including boring logs, compaction
requirements, and recommendations for construction of detention basins.
(3)
Karst Features Identification and Analysis Reports and a hydrogeologic
assessment of the effects of runoff on sinkholes.
(4)
The effect of the project (in terms of runoff volumes and peak
flows) on adjacent properties and on any existing Borough stormwater
collection system that may receive runoff from the project site.
(5)
A Declaration of Adequacy and Highway Occupancy Permit from
PaDOT District Office when utilization of a PaDOT storm drainage system
is proposed.
(6)
All permits required by the Pennsylvania Department of Environmental
Resources and Army Corps of Engineers and other regulatory agencies.
d.
Stormwater Management Facilities.
(1)
All stormwater management facilities must be located on a plan
and described in detail.
(2)
When groundwater recharge methods such as seepage pits, beds
or trenches are used, the locations of existing and proposed septic
tank infiltration areas and wells must be shown.
(3)
All calculations, assumptions, and criteria used in the design
of the stormwater management facilities must be shown.
(a)
A sketch of the berm embankment and outlet structure indicating
the embankment top elevation, embankment side slopes, top width of
embankment, emergency spillway elevation, perforated riser dimensions,
pipe barrel dimensions and dimensions and spacing of antiseep collars.
(b)
Design computations for the pipe barrel and riser.
(c)
A plot or table of the stage-storage (acre-feet versus elevation)
and all supporting computations.
(d)
Flood routing computations.
(e)
A detailed plan of the trash rack and anti-vortex device.
(4)
Record Set (As-Built) Plans: At the completion of the project,
and as a prerequisite for the release of the guarantee or issuance
of an occupancy permit, the owner or his representative shall:
(a)
Provide certification of completion from a registered professional
verifying that all permanent facilities have been constructed according
to the plans and specifications and approved revisions thereto; and
(b)
Provide a set of approved stormwater management plan drawings
in electronic format in accordance with State College Borough Zoning
Requirements showing all approved revisions and elevations and inverts
to all manholes, inlets, pipes, and stormwater control facilities.
[Ord. 1741, 3/17/2003, Section 121; amended by Ord. 2049,
10/6/2014]
For all activities regulated by this ordinance, the steps below
shall be followed for submission. For any activities that require
a PA DEP Joint Permit Application and regulated under Chapter 105
(Dam Safety and Waterway Management) or Chapter 106 (Floodplain Management)
of PA DEP's Rules and Regulations, require a PaDOT Highway Occupancy
Permit, or require any other permit under applicable state or federal
regulations, the permit(s) shall be part of the plan.
[Ord. 1741, 3/17/2003, Section 122; amended by Ord. 2049,
10/6/2014]
a.
The Borough Engineer or designee shall review the SWM Site Plan for
consistency with the approved Spring Creek Watershed Act 167 Stormwater
Management Plan. The Borough shall require receipt of a complete plan,
as specified in this ordinance.
b.
The Borough Engineer shall ensure that all other ordinances applicable
to stormwater management are complied with.
c.
For activities regulated by this ordinance, the Borough Engineer
or designee shall notify the Borough Planning Department in writing,
within 30 calendar days, whether the SWM Site Plan is consistent with
the Stormwater Management Plan. Should the SWM Site Plan be determined
to be consistent with the Stormwater Management Plan, the Borough
Engineer or designee will forward an approval letter to the Developer
with a copy to the Borough Planning Department.
d.
Should the SWM Site Plan be determined to be inconsistent with the
Stormwater Management Plan, the Borough Engineer or designee will
forward a disapproval letter to the Developer with a copy to the Borough
Planning Department citing the reason(s) for the disapproval. Any
disapproved SWM Site Plans may be revised by the Developer and resubmitted
consistent with this ordinance.
e.
For Regulated Activities requiring a PA DEP Joint Permit Application,
the Borough Engineer shall notify PA DEP whether the SWM Site Plan
is consistent with the Stormwater Management Plan and forward a copy
of the review letter to the Borough and the Developer. PA DEP may
consider the Borough Engineer's review comments in determining whether
to issue a permit.
f.
The Borough shall not approve any subdivision or land development
for Regulated Activities specified in § 14-104a and b of
this ordinance if the SWM Site Plan has been found to be inconsistent
with the Stormwater Management Plan, as determined by the Borough
Engineer or designee. All required permits from PA DEP must be obtained
prior to approval.
g.
The Borough Planning Department shall not issue a zoning permit for
any Regulated Activity specified in § 14-204 of this ordinance
if the Drainage Plan has been found to be inconsistent with the Stormwater
Management Site Plan, as determined by the Borough Engineer, or without
considering the comments of the Borough Engineer. All required permits
from PA DEP must be obtained prior to issuance of a zoning permit.
h.
The Developer shall be responsible for completing an "As-Built Survey"
of all stormwater management facilities included in the approved SWM
Site Plan. The As-Built Survey and an explanation of any discrepancies
with the design plans shall be submitted in electronic format in accordance
with State College Borough Zoning Regulations to the Borough Engineer
for final approval. In no case shall the Borough approve the As-Built
Survey until the Borough receives a copy of an approved Declaration
of Adequacy, Highway Occupancy Permit from the PaDOT District Office,
and any applicable permits from PA DEP.
i.
The Borough's approval of a SWM Site Plan shall be valid for a period
not to exceed five years. This five-year time period shall commence
on the date that the Borough signs the approved SWM Site Plan. If
stormwater management facilities included in the approved SWM Site
plan have not been constructed, or if an As-Built Survey of these
facilities has not been approved within this five-year time period,
then the Borough may consider the SWM Site plan disapproved and may
revoke any and all permits unless a time extension is granted by the
Borough. SWM Site Plans that are considered disapproved by the Borough
shall be resubmitted in accordance with § 14-226 of this
ordinance.
[Ord. 1741, 3/17/2003, Section 123; amended by Ord. 2049,
10/6/2014]
A modification to a submitted SWM Site Plan for a development
site that involves a change in stormwater management facilities or
techniques, or that involves the relocation or re-design of stormwater
management facilities, or that is necessary because soil or other
conditions are not as stated on the SWM Site Plan as determined by
the Borough Engineer, shall require a resubmission of the modified
SWM Site Plan consistent with § 14-223 of this ordinance
and be subject to review as specified in § 14-224 of this
ordinance.
A modification to an already approved or disapproved SWM Site
Plan shall be submitted to the Borough, accompanied by the applicable
review. A modification to a SWM Site Plan for which a formal action
has not been taken by the Borough shall be submitted to the Borough,
accompanied by the applicable Review Fee.
[Ord. 1741, 3/17/2003, Section 124; amended by Ord. 2049,
10/6/2014]
A disapproved SWM Site Plan may be resubmitted, with the revisions
addressing the Borough Engineer's concerns documented in writing,
to the Borough Engineer in accordance with § 14-223 of this
ordinance and is subject to review as specified in § 14-224
of this ordinance. The applicable fee must accompany a resubmission
of a disapproved SWM Site Plan.
[Ord. 1741, 3/17/2003, Section 125; amended by Ord. 2049,
10/6/2014]
a.
The Borough Engineer or designee shall inspect all phases of the
installation of the permanent stormwater management facilities.
b.
During any stage of the work, if the Borough Engineer determines
that the permanent stormwater management facilities are not being
installed in accordance with the approved Stormwater Management Plan,
the Borough shall revoke any existing permits until a revised SWM
Site Plan is submitted and approved, as specified in this ordinance.
[Ord. 1741, 3/17/2003, Section 126; amended by Ord. 2049,
10/6/2014]
The applicant shall pay all costs associated with the review,
approval and inspection of the SWM Site Plan. The costs, at a minimum,
shall include:
a.
Administrative Costs.
b.
The review of the SWM Site Plan by the Borough Engineer, consultant
or designee.
c.
The site inspections.
d.
The inspection of stormwater management facilities and drainage improvements
during construction.
e.
The final inspection upon completion of the stormwater management
facilities and drainage improvements presented in the SWM Site Plan.
f.
Any additional work required to enforce any permit provisions regulated
by this ordinance, correct violations, and assure proper completion
of stipulated remedial actions.
g.
Meetings.
The applicant shall deposit escrow as established by resolution
to cover all costs incurred by the Borough associated with the review,
approval and inspection of the SWM Site Plan, as noted in § 14-228.
[Ord. 1741, 3/17/2003, Section 127; amended by Ord. 2049,
10/6/2014]
Stormwater management controls and facilities as defined here
include all structural and non-structural stormwater conveyance and
management controls including water quantity and quality Best Management
Practices.
[Ord. 1741, 3/17/2003, Section 128; amended by Ord. 2049,
10/6/2014]
The applicant should provide a letter of credit, surety, or
provision for security interest acceptable to the Borough of State
College for the timely installation and proper construction of all
stormwater management controls as required by the approved stormwater
plan and this ordinance equal to the full construction cost of the
required controls.
[Ord. 1741, 3/17/2003, Section 129; amended by Ord. 2049,
10/6/2014]
a.
The SWM Site Plan for the development site shall contain an operation
and maintenance plan prepared by the developer and approved by the
Borough Engineer. The operation and maintenance plan shall be submitted
in two parts. The first shall outline required routine maintenance
actions and schedules necessary to ensure proper operation and function
of the facility(ies). The second shall outline a proposed plan for
an extensive rebuild in the event of failure of the structure.
b.
The responsible party or entity responsible for the maintenance must
also be identified. The SWM Site Plan for the development site shall
establish responsibilities for the continuing operation and maintenance
of all proposed stormwater control facilities and temporary permanent
erosion control facilities, consistent with the following principals:
(1)
If a development consists of structures or lots that are to
be separately owned and in which streets, sewers and other public
improvements are to be dedicated to the Borough, stormwater control
facilities may also be dedicated to and maintained by the Borough.
(2)
If a development site is to be maintained in a single ownership
or if sewers and other public improvements are to be privately owned
and maintained, then the ownership and maintenance of stormwater control
facilities shall be the responsibility of the owner or private management
entity.
Facilities may be incorporated within individual lots so that
the respective lot owners will own and be responsible for maintenance
in accordance with recorded deed restriction. A description of the
facility or system and the terms of the required maintenance shall
be incorporated as part of the deed to the property.
Ownership and maintenance may be the responsibility of a Property
Owners Association. The stated responsibilities of the Property Owners
Association in terms of owning and maintaining the stormwater management
facilities shall be submitted with final plans for determination of
their adequacy, and upon their approval shall be recorded with the
approved subdivision plan among the deed records of Centre County,
Pennsylvania. In addition, the approved subdivision plan and any deed
written from said plan for a lot or lots shown herein shall contain
a condition that it shall be mandatory for the owner or owners of
said lot to be members of said Property Owners Association.
For stormwater management facilities that are proposed as part
of the site development plan, the developer will be required to execute
a developer agreement and a maintenance agreement with the Borough
for the construction and continued maintenance of the facilities prior
to the signature approval on the final plan. Access for inspection
by the Borough of all such facilities deemed critical to the public
welfare at any reasonable time shall be provided.
c.
The governing body, upon recommendation of the Borough Engineer,
shall make the final determination on the continuing maintenance responsibilities
prior to final approval of the stormwater management plan. The governing
body reserves the right to accept the ownership and operating responsibility
for any or all of the stormwater management controls.
[Ord. 1741, 3/17/2003, Section 130; amended by Ord. 2049,
10/6/2014]
a.
Prior to final approval of the site's stormwater management site
plan, if the stormwater management facility is not dedicated to the
Borough, the property owner shall sign and record a Stormwater Access
and Maintenance Agreement (SWAME) covering all stormwater control
facilities that are to be privately owned. The SWAME shall contain
the following elements:
(1)
Name and address of the property owner.
(2)
Name of Land Development for which the SWAME is required.
(3)
Statement noting that as a condition of approval that a SWAME
is required.
(4)
Statement noting that the SWAME shall run in perpetuity with
the land.
(5)
Statement that the property owner allow access to the Borough
for the purpose of access to the stormwater facilities for ingress,
egress, and regress.
(6)
Metes and bounds description of any required Stormwater Access
and Maintenance Easement.
(7)
Statement that heirs and assigns of the owner, by accepting
a deed from the owner, agree to be subject to the conditions of the
SWAME.
(8)
Statement that any stormwater easement shall be a permanent
easement and that the stormwater management facilities located within
the easement will be maintained by the owner, their heirs and assigns
and shall be responsible for repairs as may be required in accordance
with the approved Stormwater Management Site Plan.
(9)
The creation of the stormwater agreement shall be deemed an
agreement by the Owner to maintain the stormwater management facilities
with all costs of maintenance to be the responsibility of the Owner.
The agreement shall also state that no alteration of the facilities
is permitted without formal plan approval by DEP, the Centre County
Conservation District and the Borough.
(10)
Statement noting that no structures are permitted within an
easement and that no grading that will adversely impact the function
of stormwater facilities within an easement.
(11)
A statement noting that no barriers, fences or other obstructions
that may impede stormwater flow are permitted.
(12)
A statement noting that Owner will be responsible for maintenance
of the Stormwater Management Facilities including mowing and annual
upkeep.
(13)
Statement noting that in case any provisions contained in this
SWAME are for any reason declared invalid, that such invalidity shall
not affect any other provision hereof.
(14)
Statement that the Owner their heirs, successors, and assigns
agree to indemnify and hold harmless the Borough, Centre County, and
the Borough Engineer from any and all claims, costs, damages, and
expenses legally and reasonably incurred as a result of this SWAME
and the easements hereby created.
(15)
Statement noting the following: "The Owner hereby acknowledges
the Borough's right to access the site to inspect the stormwater management
facilities. The Owner also acknowledges the Borough's right, upon
notice to the Owner, to repair and or maintain the stormwater facilities
in accordance with the Stormwater Access and Maintenance Plan. All
costs, including materials, labor, engineering, and legal costs of
such repair or maintenance activities shall be the sole responsibility
of the Owner." In the event of non-payment by the Owner, the Borough
shall seek legal options for receipt of payment including placement
of a Municipal Lien on the property.
[Ord. 1741, 3/17/2003, Section 132; amended by Ord. 2049,
10/6/2014]
b.
The entity conducting the inspection should be required to submit
a report to the Borough regarding the condition of the facility and
recommending necessary repairs, if needed.
c.
Maintenance inspections may be performed by the Borough to ensure
proper functioning of all stormwater facilities. These inspections
may, at a minimum, be performed annually and/or following major storm
events. If the Borough determines at any time that any permanent stormwater
facility has been eliminated, altered or improperly maintained, the
owner of the property shall be advised of corrective measures required
and given three days to initiate appropriate action in accordance
with a time schedule dictated by the Borough. If such action is not
taken by the property owner, the Borough may cause the work to be
done and backcharge all costs to the property owners.
[Ord. 1741, 3/17/2003, Section 133; amended by Ord. 2049,
10/6/2014]
Upon presentation of proper credentials, duly authorized representatives
of the Borough of State College may enter, at reasonable times, upon
any property within the Borough to inspect the condition of the stormwater
structures and facilities in regard to any aspect regulated by this
ordinance. Access easements will be required to enable the Borough
to inspect or repair structures. Easements shall be a minimum width
of 20 feet or a width determined by the Borough Engineer to be adequate
and shall be shown on the plan.
[Ord. 1741, 3/17/2003, Section 134; amended by Ord. 1774,
3/2/2004, Section 5; Ord. 2049, 10/6/2014]
a.
In the event that a person fails to comply with the requirements
of this Ordinance, or fails to conform to the requirements of any
permit issued hereunder, the Borough shall provide written notification
of the violation. The notice will direct the responsible party to
comply with all the terms of this Ordinance within seven days, or
such additional period, not to exceed 30 days, as the designated Borough
representative shall deem reasonable. In addition, the designated
Borough representative shall give notice to the owner, applicant,
developer, property manager or other person responsible for the property
or the violation that if the violation is not corrected, the Borough
may correct the same and charge the landowner or other person responsible
the cost thereof plus penalties as specified herein for failure to
comply.
b.
Such notice may be delivered by the United States mail, first class,
postage prepaid, by certified or registered mail; by personal service;
or, if the property is occupied, by posting the notice at a conspicuous
place upon the affected property.
c.
Such notification shall set forth the nature of the violations(s)
and establish a time limit for correction of these violation(s). Failure
to comply within the time specified shall subject such person to the
penalty provision of this ordinance. All such penalties shall be deemed
cumulative and shall not prevent the Borough from pursuing any and
all other remedies available in law or equity. It shall be the responsibility
of the owner of the real property on which any regulated activity
is proposed to occur, is occurring, or has occurred, to comply with
the terms and conditions of this ordinance.
[Ord. 1741, 3/17/2003, Section 135; amended by Ord. 2049,
10/6/2014]
The Borough of State College is hereby authorized and directed
to enforce all of the provisions of this ordinance. All inspections
regarding verification of compliance with the SWM Site Plan shall
be the responsibility of the Borough Engineer or other qualified persons
designated by the Borough. Inspection frequency will be deemed as
necessary by the Borough Engineer and will be based on past performance
of the facility, compliance history of the owner of the facility with
inspection and maintenance requirements and weather conditions.
a.
A set of design plans approved by the Borough shall be on file at
the site throughout the duration of the construction activity. Periodic
inspections may be made by the Borough or designee during construction.
b.
Adherence to Approved Plan. It shall be unlawful for any person,
firm or corporation to undertake any regulated activity under § 14-204
on any property except as provided for in the approved SWM Site Plan
and pursuant to the requirements of this ordinance. It shall be unlawful
to alter or remove any control structure required by the SWM Site
Plan pursuant to this ordinance or to allow the property to remain
in a condition which does not conform to the approved SWM Site Plan.
c.
At the completion of the project, and as a prerequisite for the release
of the performance guarantee, the owner or his representatives shall:
(1)
Provide a certification of completion from an engineer, architect,
surveyor or other qualified person verifying that all permanent facilities
have been constructed according to the plans and specifications and
approved revisions thereto.
(2)
Provide a set of as-built drawings in electronic format in accordance
with the Borough Zoning Regulations.
d.
After receipt of the certification by the Borough, a final inspection
shall be conducted by the Borough Engineer or designee to certify
compliance with this ordinance.
e.
Occupancy Permit. An occupancy permit shall not be issued until all
stormwater issues have been addressed to the Borough Engineer's satisfaction.
The occupancy permit shall be required for each lot owner and/or developer
for all subdivisions and land development in the Borough.
[Ord. 2049, 10/6/2014]
a.
Any permit issued under this ordinance may be suspended or revoked
by the Borough for:
(1)
Non-compliance with or failure to implement any provision of
the permit.
(2)
A violation of any provision of this ordinance or any other
applicable law, ordinance, rule or regulation relating to the project.
(3)
The creation of any condition or the commission of any act during
construction or development which constitutes or creates a hazard
or nuisance, pollution or which endangers the life or property of
others.
b.
A suspended permit shall be reinstated by the Borough when:
(1)
The Borough Engineer or his designee has inspected and approved
the corrections to the stormwater management and erosion and sediment
pollution control measure(s), or the elimination of the hazard or
nuisance;
(2)
The violation of the ordinance, law, or rule and regulation
has been corrected.
A permit that has been revoked by the Borough cannot be reinstated.
The applicant may apply for a new permit under the procedures outlined
in this ordinance.
[Ord. 1741, 3/17/2003, Section 136; amended by Ord. 2049,
10/6/2014]
a.
Anyone violating the provisions of this ordinance shall be guilty
of a summary offense, and upon conviction shall be subject to a fine
of not more than $300 for each violation and recoverable with costs.
Each day that the violation continues shall be a separate offense.
b.
In addition, the Borough, through its solicitor, may institute injunctive,
mandamus or any other appropriate action or proceeding at law or in
equity for the enforcement of this ordinance. Any court of competent
jurisdiction shall have the right to issue restraining orders, temporary
or permanent injunctions, mandamus or other appropriate forms of remedy
or relief.
[Ord. 1741, 3/17/2003, Section 137; amended by Ord. 2049,
10/6/2014]
a.
Any person aggrieved by any action of the Borough, its engineer or
its designee, relevant to the provisions of this ordinance, may appeal
to the State College Zoning Hearing Board within 30 days of that action.
b.
Any person aggrieved by any decision of the State College Zoning
Hearing Board, relevant to the provisions of this ordinance, may appeal
to the Court of Common Pleas of Centre County within 30 days of the
Zoning Hearing Board's decision.
