CITY OF BETHLEHEM
STORMWATER MANAGEMENT ORDINANCE
925.01 SHORT TITLE
This Ordinance shall be known and may be cited as the “City of Bethlehem Stormwater
925.02 STATEMENT OF FINDINGS
The governing body of the municipality finds that:
A. Inadequate management of accelerated runoff of stormwater resulting from development
throughout a watershed increases flood flows and velocities, contributes to erosion and
sedimentation, changes the natural hydrologic patterns, destroys aquatic habitat, elevates
aquatic pollutant concentrations and loadings, overtaxes the carrying capacity of streams
and storm sewers, greatly increases the cost of public facilities to carry and control
stormwater, undermines floodplain management and flood control efforts in downstream
communities, reduces groundwater recharge, and threatens public health and safety.
B. A comprehensive program of stormwater management, including reasonable regulation
of development and activities causing accelerated erosion and loss of natural infiltration,
is fundamental to the public health, safety and welfare and the protection of the people of
the municipality and all the people of the Commonwealth, their resources and the
C. Stormwater can be an important resource by providing groundwater recharge for water
supplies and baseflow of streams, which also protects and maintains surface water
D. Public education on the control of pollution from stormwater is an essential component
in successfully addressing stormwater.
E. Federal and state regulations require certain municipalities to implement a program of
stormwater controls. These municipalities are required to obtain a permit for stormwater
discharges from their separate storm sewer systems under the National Pollutant
Discharge Elimination System (NPDES).
F. Non-stormwater discharges to municipal separate storm sewer systems can contribute to
pollution of waters of the Commonwealth by the municipality.
The purpose of this Ordinance is to promote the public health, safety and welfare within the
City‟s Watersheds by minimizing the damages and maximizing the benefits described in Section
925.02 of this Ordinance by provisions designed to:
A. Manage stormwater runoff impacts at their source by regulating activities which cause
B. Utilize and preserve the desirable existing natural drainage systems.
C. Encourage infiltration of stormwater, where appropriate, to maintain groundwater
recharge, to prevent degradation of surface and groundwater quality and to otherwise
protect water resources.
D. Maintain the existing flows and quality of streams and watercourses in the municipality
and the Commonwealth.
E. Preserve and restore the flood carrying capacity of streams.
F. Provide for proper maintenance of all permanent stormwater management BMPs that are
implemented in the City.
G. Provide review procedures and performance standards for stormwater planning, design
* H. Manage stormwater impacts close to the runoff source which requires a minimum of
structures and relies on natural processes.
I. Meet legal water quality requirements under state law, including regulations at 25 Pa.
Code Chapter 93.4a to protect and maintain “existing uses” and maintain the level of
water quality to support those uses in all streams and to protect and maintain water
quality in “special protection” streams.
J. Prevent scour and erosion of streambanks and streambeds.
K. Provide standards to meet the NPDES permit requirements.
925.04 STATUTORY AUTHORITY
The City is empowered to regulate these activities by the authority of the Act of October 4,
1978, P.L. 864 (Act 167), 32 P.S. Section 680.1, et seq., as amended, the “Stormwater Management
Act” and the “Pennsylvania Municipalities Planning Code”, 53. P.S. Section 10101, et seq.
This Ordinance shall apply to those areas of the City which are located within the Catasauqua
Creek & Lehigh River Sub-Basin, Monocacy Creek, Nancy Run and Saucon Creek Watersheds as
delineated on the official maps available for inspection at the City, Engineering Bureau.
The following activities are defined as Regulated Activities and shall be regulated by this
A. Land development.
C. Construction of new or additional impervious surfaces (driveways, parking lots, etc.).
D. Construction of new buildings or additions to existing buildings, including residential
E. Earth moving
F. Agricultural Operations
G. Forest Management Operations
H. Nursery Operations
I. Diversion or piping of any natural or man-made stream channel.
J. Installation of stormwater systems or appurtenances thereto.
K. Regulated Earth Disturbance Activities.
A. Impervious Cover - Any proposed Regulated Activity, except those defined in Section
925.05I and 925.05J, which would create 10,000 square feet or less of additional
impervious cover is exempt from the Drainage Plan preparation provisions of this
Ordinance except as cited in Section 925.06C and D. The date of the City Ordinance
adoption of the original Act 167 Stormwater Management Ordinances (1988) shall be
the starting point from which to consider tracts as “parent tracts” in which future
subdivisions and respective impervious area computations shall be cumulatively
considered. For development taking place in stages, the entire development plan must be
used in determining conformance with this criteria. Additional impervious cover shall
include, but not be limited to, any roof, parking or driveway areas and any new streets
and sidewalks constructed as part of or for the proposed Regulated Activity. Any
additional areas proposed to initially be gravel, crushed stone, porous pavement, etc.
shall be assumed to be impervious for the purposes of comparison to the exemption
criteria. Any existing gravel, crushed stone or hard packed soil areas on a site shall be
considered as pervious cover for the purpose of exemption evaluation. All of the
impervious cover added incrementally to a site above the initial 10,000 square feet shall
be subject to the provisions of this Ordinance. If a site has previously received an
exemption and is proposing additional development such that the total impervious cover
on the site exceeds 10,000 square feet, the total impervious cover on the site proposed
since the original ordinance date must meet the provisions of this Ordinance.
B. Prior Drainage Plan Approval - Any Regulated Activity for which a Drainage Plan was
previously prepared as part of a subdivision or land development proposal that received
preliminary plan approval from the municipality prior to the effective date of this
Ordinance is exempt from the water quantity provisions of this Ordinance, except as
cited in Section 925.06C, provided that the approved Drainage Plan included design of
stormwater facilities to control runoff from the site currently proposed for development consistent with ordinance provisions in effect at the time of approval and the approval
has not lapsed under the Municipalities Planning Code. If significant revisions are made to the Drainage Plan after both the preliminary plan approval and the effective date of
this Ordinance, preparation of a new Drainage Plan, subject to the provisions of this
Ordinance, shall be required. Significant revisions would include a change in control
methods or techniques, relocation or redesign of control measures or changes necessary
because soil or other conditions are not as stated on the original Drainage Plan.
C. These exemptions 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. These exemptions shall not relieve the applicant from meeting the water quality standards in this Ordinance for all development proposed since the municipal adoption date of this Ordinance.
D. Any regulated activity that meets the exemption criteria in Section 925.06A or B, in lieu of meeting the water quality criteria in Section 925.15, will be consistent with the
Ordinance if one of the BMPs listed below is employed on the site to control water
1. Controlling runoff through a “sheet flow” system of vegetative or similar buffers
having a minimum flow length equal to the length of the impervious areas. 2. Disconnecting roof downspouts from direct discharge to curb/gutter or storm sewer
systems and allowing the downspout discharge to flow over plant, lawn or
woodland areas in such a manner as to avoid rill or gully erosion. 3. Infiltration designed to meet the provisions of this Ordinance. 4. Employing any one of the BMPs listed in Section 304.O.
Sites that meet the exemption criteria in Section 925.06A or B are not required to
conduct a Preliminary Site Investigation (as defined in Section 925.11) as long as
infiltration BMPs are not proposed. If infiltration BMPs are proposed, a Preliminary
Site Investigation shall be performed. The City shall have the authority to require,
review, approve, reject or recommend alternative methods for meeting the water quality
requirements of this Ordinance.
E. No exemptions shall be provided for regulated activities as defined in Sections 925.05I
Any ordinance of the City inconsistent with any of the provisions of this Ordinance is hereby
repealed to the extent of the inconsistency only.
Should any section or provision of this Ordinance be declared invalid by a court of competent
jurisdiction, such decision shall not affect the validity of any of the remaining provisions of this
925.09 COMPATIBILITY WITH OTHER ORDINANCE REQUIREMENTS
Approvals issued pursuant to this Ordinance do not relieve the applicant of the responsibility
to secure required permits or approvals for activities regulated by any other applicable code, rule,
act or ordinance.
925.10 DUTY OF PERSONS ENGAGED IN THE DEVELOPMENT OF LAND
Notwithstanding any provisions of this Ordinance, including exemption and waiver provisions,
any landowner and any person engaged in the alteration or development of land which may affect
stormwater runoff characteristics shall implement such measures as are reasonably necessary to
prevent injury to health, safety or other property. Such measures shall include such actions as are
required to manage the rate, volume, direction and quality of resulting stormwater runoff in a
manner which otherwise adequately protects health and property from possible injury.
For the purposes of this Ordinance, certain terms and words used herein shall be interpreted as
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 words “shall” and “must” are mandatory; the words “may” and “should” are permissive.
Accelerated Erosion – The removal of the surface of the land through the combined action of
human activities and natural processes, at a rate greater than would occur because of the natural
Act 167 – Act of October 4, 1978, P.L. 864, the “Stormwater Management Act.”
Act 247 – Act of 1968, P.L. 805, No. 247 “ Pennsylvania Municipalities Planning Code.”
Best Management Practice (BMP) – Activities, facilities, measures or procedures used to manage
stormwater quantity and quality impacts from the regulated activities listed in Section 105, to meet
State Water Quality Requirements, to promote groundwater recharge and to otherwise meet the
purposes of this Ordinance.
Best Management Practice Operations and Maintenance Plan – Documentation, included as
part of a Drainage Plan, detailing the proposed BMPs, how they will be operated and maintained
and who will be responsible.
Bioretention – Densely vegetated, depressed features that store stormwater and filter it through
vegetation, mulch, planting soil, etc. Ultimately stormwater is evapotranspirated, infiltrated, or
discharged. Optimal bioretention areas mimic natural forest ecosystems in terms of species diversity,
density, distribution, use of native plants, etc.
Buffer – (1) Streamside Buffer - A zone of variable width located along a stream that is vegetated
and is designed to filter pollutants from runoff.
(2) Special Geologic Feature Buffer – A required isolation distance from a special
geologic feature to a proposed BMP needed to reduce the risk of sinkhole formation due to
stormwater management activities.
Capture/Reuse – Stormwater management techniques such as cisterns and rain barrels which direct runoff into storage devices, surface or sub-surface, for later re-use, such as for irrigation of gardens
and other planted areas. Because this stormwater is utilized and no pollutant discharge results,
water quality performance is superior to other non-infiltration BMPs.
Carbonate Bedrock – Rock consisting chiefly of carbonate minerals, such as limestone and dolomite; specifically a sedimentary rock composed of more than 50% by weight of carbonate
minerals that underlies soil or other unconsolidated, superficial material.
Cistern – An underground reservoir or tank for storing rainwater.
City – City of Bethlehem.
Closed Depression – A distinctive bowl-shaped depression in the land surface. It is characterized by internal drainage, varying magnitude, and an unbroken ground surface.
Conservation District – The Lehigh or Northampton County Conservation District, as applicable.
Constructed Wetlands – Constructed wetlands are similar to wet ponds (see below) and consist of a basin which provides for necessary stormwater storage as well as a permanent pool or water level,
planted with wetland vegetation. To be successful, constructed wetlands must have adequate natural
hydrology (both runoff inputs as well as soils and water table which allow for maintenance of a
permanent pool of water). In these cases, the permanent pool must be designed carefully, usually
with shallow edge benches, so that water levels are appropriate to support carefully selected wetland
Culvert – A pipe, conduit or similar structure including appurtenant works which carries surface
Dam – An artificial barrier, together with its appurtenant works, constructed for the purpose of
impounding or storing water or another fluid or semifluid or a refuse bank, fill or structure for
highway, railroad or other purposes which does or may impound water or another fluid or semifluid.
DEP – The Pennsylvania Department of Environmental Protection (formerly the Pennsylvania
Department of Environmental Resources).
Design Storm – The depth and time distribution of precipitation from a storm event measured in probability of occurrence (e.g., 50-yr. storm) and duration (e.g. 24-hour), and used in computing
stormwater management control systems.
Detention Basin – A basin designed to retard stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate.
Developer – A person, partnership, association, corporation or other entity, or any responsible person therein or agent thereof, that undertakes any Regulated Activity of this Ordinance.
Development Site – The specific tract of land for which a Regulated Activity is proposed.
Diffused Drainage – See Sheet Flow.
Drainage Easement – A right granted by a land owner to a grantee, allowing the use of private land for stormwater management purposes.
Drainage Plan – The documentation of the proposed stormwater quantity and quality management controls to be used for a given development site, including a BMP Operations and Maintenance Plan,
the contents of which are established in Section 925.21.
Earth Disturbance Activity – A construction or other human activity which disturbs the surface of
the land, including, but not limited to, clearing and grubbing, grading, excavations, embankments,
road maintenance, building construction and the moving, depositing, stockpiling or storing of soil,
rock or earth materials.
Erosion – The removal of soil particles by the action of water, wind, ice, or other geological agents.
Existing Uses – Those uses actually attained in the water body on or after November 28, 1975, whether or not they are included in the water quality standards. (25 Pa. Code Chapter 93.1)
Fill – Man-made deposits of natural soils or rock products and waste materials.
Filter Strips – see Vegetated Buffers.
Freeboard – The incremental depth in a stormwater management structure, provided as a safety factor of design, above that required to convey the design runoff event.
Groundwater Recharge – Replenishment of existing natural underground water supplies.
Hardship Waiver Request – A written request for a waiver alleging that the provisions of this Ordinance inflict unnecessary hardship upon the applicant. Waivers from the water quality
provisions of this Ordinance shall not be granted.
Hot Spot Land Uses – A Land Use or activity that generates higher concentrations of hydrocarbons, trace metals or other toxic substances than typically found in stormwater runoff. These land uses are
listed in Section 925.15P.
Hydrologic Soil Group (HSG) – Soils are classified into four HSGs (A, B, C and D) to indicate the minimum infiltration rates, which are obtained for bare soil after prolonged wetting. The
Natural Resources Conservation Service (NRCS) of the US Department of Agriculture defines the
four groups and provides a list of most of the soils in the United States and their group classification.
The soils in the area of the development site may be identified from a soil survey report that can be
obtained from local NRCS offices or conservation district offices. Soils become less permeable as
the HSG varies from A to D.
Impervious Surface (Impervious Cover) – A surface which prevents the percolation of water into
Infiltration Practice – A practice designed to direct runoff into the ground, e.g. French drain, seepage pit, seepage trench or bioretention area.
Infiltration Structure – A structure designed to direct runoff into the ground, e.g. French drain, seepage pit, trench or perforated pipe or similar.
Karst – A type of topography or landscape characterized by depressions, sinkholes, limestone
towers and steep-sided hills, underground drainage and caves. Karst is usually formed on carbonate
rocks, such as limestones or dolomites and sometimes gypsum.
Land Development – (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) a subdivision of land; (iii) development in accordance with Section 503(1.1) of
the Pennsylvania Municipalities Planning Code.
Loading Rate – The ratio of the land area draining to the system, as modified by the weighting
factors in Section 925.18B, compared to the base area of the infiltration system.
Low Impact Development – A development approach that promotes practices that will minimize post-development runoff rates and volumes thereby minimizing needs for artificial conveyance and
storage facilities. Site design practices include preserving natural drainage features, minimizing
impervious surface area, reducing the hydraulic connectivity of impervious surfaces, and protecting
natural depression storage.
“Local” Runoff Conveyance Facilities – Any natural channel or manmade conveyance system
which has the purpose of transporting runoff from the site to the mainstream.
LVPC – Lehigh Valley Planning Commission of Lehigh and Northampton Counties.
Mainstem (main channel) – Any stream segment or other conveyance used as a reach in the Lehigh, Monocacy, Nancy Run or Saucon Creek hydrologic model.
Manning Equation (Manning formula) – A method for calculation of velocity of flow (e.g. feet
per second) and flow rate (e.g. cubic feet per second) in open channels based upon channel shape,
roughness, depth of flow and slope. “Open channels” may include closed conduits so long as the
flow is not under pressure.
Maryland Stormwater Design Manual – A stormwater design manual written by the Maryland
Department of the Environment and the Center for Watershed Protection. As of January 2004, the
Manual can be obtained through the following web site: www.mde.state.md.us.
Minimum Disturbance/Minimum Maintenance Practices (MD/MM) – A site design practice in
which careful limits are placed on site clearance prior to development allowing for maximum
retention of existing vegetation (woodlands and other), minimum disturbance and compaction of
existing soil mantle and minimum site application of chemicals post-development. Typically,
MD/MM includes disturbance setback criteria from buildings as well as related site improvements
such as walkways, driveways, roadways, and any other improvements. These criteria may vary by
community context as well as by type of development being proposed. Additionally, MD/MM also
shall include provisions (e.g., deed restrictions, conservation easements) to protect these areas from
future disturbance and from application of fertilizers, pesticides, and herbicides.
Municipality – City of Bethlehem, Lehigh or Northampton County (as applicable), Pennsylvania.
No Harm Option – The option of using a less restrictive runoff quantity control if it can be shown that adequate and safe runoff conveyance exists and that the less restrictive control would not
adversely affect health, safety and property.
NPDES – National Pollutant Discharge Elimination System.
NRCS – Natural Resource Conservation Service - U.S. Department of Agriculture. (Formerly the
Soil Conservation Service.)
Oil/Water Separator – A structural mechanism designed to remove free oil and grease (and possibly solids) from stormwater runoff.
Open Channel – Any storm water conveyance facility through which water normally flows by
gravity. An open channel may be exposed, such as a swale, street gutter, or stream; or unexposed
such as a culvert.
Outfall – “Point source” as described in 40 CFR ? 122.2 at the point where the City‟s storm sewer
system discharges to surface waters of the Commonwealth.
Peak Discharge – The maximum rate of flow of stormwater runoff at a given location and time
resulting from a specified storm event.
Penn State Runoff Model (PSRM) – The computer-based hydrologic modeling technique used in previous Act 167 Plans. PSRM was also updated to include water quality modeling capabilities and
renamed PSRM-QUAL. The PSRM and PSRM-QUAL calculation methodologies were used as the
basis for writing the WATERSHED model.
Person – An individual, partnership, public or private association or corporation, or a governmental
unit, public utility or other for or not for profit statutory entity or other legal entity whatsoever which
is recognized by law as the subject of rights and duties.
Point Source – any discernible, confined and discrete conveyance, including, but not limited to, any
pipe, ditch, channel, tunnel or conduit from which stormwater is or may be discharged, as defined in
State regulations at 25 Pa. Code ? 92.1.
Preliminary Site Investigation – The determination of the depth to bedrock, the depth to the seasonal high water table and the soil permeability for a possible infiltration location on a site
through the use of published data and on-site surveys. In carbonate bedrock areas, the location of
special geologic features must also be determined along with the associated buffer distance to the
possible infiltration area. See Appendix G.
Public Water Supplier – A person who owns or operates a public water system.
Public Water System – A system which provides water to the public for human consumption which has at lest 15 service connections or regularly serves an average of at least 25 individuals
daily at least 60 days out of the year. (See 25 Pa. Code Chapter 109)
Qualified Geotechnical Professional – A licensed professional geologist or a licensed professional
engineer who has a background or expertise in geology or hydrogeology.
Rational Method – A method of peak runoff calculation using a standardized runoff coefficient
(rational „c‟), acreage of tract and rainfall intensity determined by return period and by the time
necessary for the entire tract to contribute runoff. The rational method formula is stated as follows:
Q = ciA, where “Q” is the calculated peak flow rate in cubic feet per second, “c” is the
dimensionless runoff coefficient (see Appendix C), “i” is the rainfall intensity in inches per hour, and
“A” is the area of the tract in acres.
Reach – Any of the natural or man-made runoff conveyance channels used for watershed runoff
modeling purposes to connect the subareas and transport flows downstream.
Recharge Volume (Rev) – The portion of the water quality volume (WQv) used to maintain groundwater recharge rates at development sites. (see Section 925.15J)
Regulated Activities – Actions or proposed actions which impact upon proper management of