[HISTORY: Adopted by the Borough Council of the Borough of
Northampton as indicated in article histories. Amendments noted where
applicable.]
[Adopted 2-5-1998 by Ord. No. 1086]
This article shall be known as the "Stormwater Management Ordinance
of the Borough of Northampton."
The Council of the Borough of Northampton 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, 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,
is fundamental to the public health, safety and welfare and the protection
of the people of the Borough and all the people of the commonwealth,
their resources and the environment.
The purpose of this article is to promote the public health, safety and welfare within the Catasauqua Creek Study Area by minimizing the damages described in § 203-2A of this article by provisions designed to:
A.
Control accelerated runoff and erosion and sedimentation problems
at their source by regulating activities which cause such problems.
B.
Utilize and preserve the desirable existing natural drainage systems.
C.
Encourage recharge of groundwaters where appropriate.
D.
Maintain the existing flows and quality of streams and watercourses
in the Borough and the commonwealth.
E.
Preserve and restore the flood-carrying capacity of streams.
F.
Provide for proper maintenance of all permanent stormwater management
structures which are constructed in the Borough.
The Borough is empowered to regulate these activities by the
authority of the Act of October 4, 1978, P.L. 864 (Act 167), as amended,
the Stormwater Management Act and the Borough Code.[1]
[1]
Editor's Note: See 32 P.S. § 680.1 et seq. and 53
P.S. § 45101 et seq., respectively.
A.
This article shall only apply to those areas of the Borough which
are located within the Catasauqua Creek Study Area as delineated on
an official map available for inspection at the Borough office. A
map of the Catasauqua Creek Study Area is included in Appendix A (Part
2I) for general reference.[1]
[1]
Editor's Note: Appendix A is on file in the Borough offices.
B.
This article shall only apply to permanent stormwater management
facilities constructed as part of any of the activities listed in
this section. Stormwater management and erosion and sedimentation
control during construction involved with any of these activities
are specifically not required by this article, but shall continue
to be regulated under existing laws and ordinances.
C.
This article contains only those stormwater runoff control criteria
and standards which are necessary or desirable from a total watershed
perspective. Additional stormwater management design criteria (i.e.,
inlet spacing, inlet type, collection system details, etc.) which
represent sound engineering practice may be regulated either by separate
stormwater ordinance provisions or as part of the general responsibilities
of the Borough Engineer.
D.
The following activities are defined as regulated activities and
shall be regulated by this article, except those which meet the waiver
specifications presented thereafter:
(1)
Land development.
(2)
Subdivision.
(3)
Construction of new or additional impervious surfaces (driveways,
parking lots, etc.).
(4)
Construction of new buildings or additions to existing buildings.
(5)
Diversion or piping of any natural or man-made stream channel.
(6)
Installation of stormwater systems or appurtenances thereto.
E.
Any proposed regulated activity, except those defined in Subsection D(5) and (6), which would create 10,000 square feet or less of additional impervious cover would be exempt from meeting the provisions of this article. Development plans qualifying for this waiver would still be regulated by § 13 of the Pennsylvania Stormwater Management Act[2] and other Borough ordinance provisions, as applicable. 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 areas which may be designed to initially be semipervious (e.g., gravel, crushed stone, porous pavement, etc.) shall be considered impervious areas for the purpose of waiver evaluation. No waiver shall be provided for regulated activities as defined in Subsection D(5) and (6) of this section.
[2]
Editor's Note: See 32 P.S. § 680.13.
Approvals issued pursuant to this article 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.
As used in this article, the following terms shall have the
meanings indicated:
The area comprised of the Catasauqua Creed Watershed and
Lehigh River Subbasin 4 (six unnamed creeks and 27 direct drainage
subareas). See map in Appendix A (Part 2I).[1]
An underground reservoir or tank for storing rainwater.
The Lehigh of Northampton County Conservation District, as
appropriate.
A pipe, conduit or similar structure including appurtenant
works which carries surface water.
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 Pennsylvania Department of Environmental Protection (formerly
the Pennsylvania Department of Environmental Resources).
The magnitude of precipitation from a storm event measured
in probability of occurrence (e.g., fifty-year storm) and duration
(e.g., twenty-four-hour) and used in computing stormwater management
control systems.
A basin designed to retard 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 article.
The specific tract of land for which a regulated activity
is proposed.
A right granted by a landowner to a grantee, allowing the
use of private land for stormwater management purposes.
The documentation of the proposed stormwater management controls, if any, to be used for a given development site, the contents of which are established in § 203-14 of this article.
The removal of soil particles by the action of water, wind,
ice or other geological agents.
The incremental depth in a stormwater management structure,
provided as a safety factor of design, above that required to convey
the design runoff event.
Replenishment of existing natural underground water supplies.
A surface which prevents the percolation of water into the
ground.
A structure designed to direct runoff into the ground, e.g.,
french drain, seepage pit or seepage trench.
Any natural channel or man-made conveyance system which has
the purpose of transporting runoff from the site to the mainstream.
Any stream segment or other conveyance in a Dual Release
Rate or Conditional No Detention I subarea used as a reach in the
Catasauqua Creek study area hydrologic model. In Conditional No Detention
II subareas, the main channel is the Lehigh River.
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.
Borough of Northampton, Northampton County, Pennsylvania.
National Pollutant Discharge Elimination System Regulations.
Natural Resource Conservation Service, U. S. Department of
Agriculture (formerly the Soil Conservation Service).
The maximum rate of flow of stream runoff at a given location
and time resulting from a specified storm event.
The computer-based hydrologic modeling technique adapted
to the Catasauqua Creek Study Area for the Act 167 Plan. The model
has been calibrated to reflect actual flow values by adjusting key
model input parameters.
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 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, Part 2I[2]), "i" is the rainfall intensity in inches per hour and
"A" is the area of the tract in acres.
Any of the natural or man-made runoff conveyance channels
used for modeling purposes to connect the subareas and transport flows
downstream.
Actions or proposed actions which impact upon proper management of stormwater runoff and which are governed by this article as specified in § 203-5.
The percentage of the predevelopment peak rate of runoff
for a development site to which the postdevelopment peak rate of runoff
must be controlled to protect downstream areas.
The average interval in years over which an event of a given
magnitude can be expected to recur. For example, the twenty-five-year
return period rainfall or runoff event would be expected to recur
on the average once every 25 years.
That part of precipitation which flows over the land.
An area of excavated earth filled with loose stone or similar
material and into which surface water is directed for infiltration
into the ground.
A method of runoff computation developed by NRCS which is
based upon relating soil type and land use/cover to a runoff parameter
called a curve number.
A reservoir routing procedure based on solution of the continuity
equation (inflow minus outflow equals the change in storage for a
given time interval) and based on outflow being a unique function
of storage volume.
Areas which lack adequate stormwater collection and/or conveyance
facilities and which present a hazard to persons or property. These
areas are either documented in Appendix B (Part 2I)[3] of this article or identified by the Borough or Borough
Engineer.
A system of pipes or other conduits which carries intercepted
surface runoff, street water and other wash waters or drainage, but
excludes domestic sewage and industrial wastes.
The plan for managing stormwater runoff adopted by Lehigh
and Northampton Counties for the Catasauqua Creek Study Area as required
by the Act of October 4, 1978, P.L. 864, (Act 167), as amended, and
known as the Stormwater Management Act.[4]
A watercourse.
The smallest unit of watershed breakdown for hydrologic modeling
purposes for which the runoff control criteria have been established
in the stormwater management plan.
The division or redivision of a lot, tract or parcel of land
by any means into two or more lots, tracts, parcels or other division
of land including changes in existing lot lines for the purpose, whether
immediate or future, of lease, transfer of ownership, or building
or lot ownership.
A low-lying stretch of land which gathers or carries surface
water runoff.
Any channel of conveyance of surface water having defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
A.
Storm drainage systems shall be provided to permit unimpeded flow
in natural watercourses except as modified by stormwater detention
facilities or open channels consistent with this article.
B.
The existing points of concentrated drainage discharge onto adjacent
property shall not be altered without written approval of the affected
property owner(s).
C.
Areas of existing diffused drainage discharge onto adjacent property
shall be managed such that, at minimum, the peak diffused flow does
not increase in the general direction of discharge, except as otherwise
provided in this article. If diffused flow is proposed to be concentrated
and discharged onto adjacent property, the downstream must document
that there are adequate downstream conveyance facilities to safely
transport the concentrated discharge or otherwise prove that no harm
will result from the concentrated discharge. Areas of existing diffused
drainage discharge shall be subject to any applicable release rate
criteria in the general direction of existing discharge whether they
are proposed to be concentrated or maintained as diffused drainage
areas.
D.
Where a site is traversed by watercourses other than those for which a one-hundred-year floodplain is defined by the Borough, there shall be provided drainage easements conforming substantially with the line of such watercourses. The width of any easement shall be adequate to provide for unimpeded flow of storm runoff based on calculations made in conformance with § 203-11 of this article for the one-hundred-year return period runoff and to provide a freeboard allowance of 0.5 foot above the design water surface level. The terms of the easement shall prohibit excavation, the placing of fill or structures and any alterations which may adversely affect the flow of stormwater within any portion of the easement. Also, periodic maintenance of the easement to ensure proper runoff conveyance shall be required. Watercourses for which the one-hundred-year floodplain is formally defined are subject to the applicable Township floodplain regulations.
E.
Any drainage facilities required by this article that are located
on state highway rights-of-way shall be subject to approval by the
Pennsylvania Department of Transportation.
F.
When it can be shown that, due to topographic conditions, natural
drainage swales on the site cannot adequately provide for drainage,
open channels may be constructed conforming substantially to the line
and grade of such natural drainage swales. Capacities of open channels
shall be calculated using the Manning equation.
G.
Storm drainage facilities and appurtenances shall be so designed
and provided as to minimize erosion in watercourse channels and at
all points of discharge.
H.
Consideration should be given to the design and use of volume controls
for stormwater management where geology and soils permit. Areas of
suitable geology for volume controls shall be determined by the Borough.
Documentation of the suitability of the soil for volume controls shall
be provided by the applicant. Volume controls shall be acceptable
in areas of suitable geology where the soils are designated as well-drained
in the County Soil Survey. Other soils may be acceptable for use of
volume controls based on site-specific soils.
A.
Mapping of stormwater management districts. To implement the provisions
of the Catasauqua Creek Watershed and Lehigh River Subbasin 4 Stormwater
Management Plan, the Borough is hereby divided into stormwater management
districts consistent with the Catasauqua Creek Release Rate Map presented
in the plan. The boundaries of the stormwater management districts
are shown on an official map which is available for inspection at
the Borough Office. A copy of the official map at a reduced scale
is included in Appendix A (Part 2I) for general reference.[1]
[1]
Editor's Note: Appendix A is on file in the Borough offices.
B.
Description of stormwater management districts. Three types of stormwater
management districts may be applicable to the Borough, namely Conditional
No Detention I Districts, Conditional No Detention II Districts and
Dual Release Rate Districts, as described below:
(1)
Conditional No Detention I Districts. Within these districts, the capacity of the local runoff conveyance facilities (as defined in § 203-7 of this article) must be calculated to calculated to determine if adequate capacity exists. For this determination, the developer must calculate peak flows assuming that the site is developed as proposed and that the remainder of the local watershed is in the existing condition. The developer must also calculate peak flows assuming that the entire local watershed is developed per current zoning and that all new development would use the runoff controls specified by this article. The larger of the two peak flows calculated will be used in determining if adequate capacity exists. If adequate capacity exists to safely transport runoff form the site to the main channel (as defined in § 203-7 of this article), these watershed areas may discharge postdevelopment peak runoff without detention facilities. If the capacity calculations show that the local runoff conveyance facilities lack adequate capacity, the developer shall either use a 100% release rate control or provide increased capacity of downstream elements to convey increased peak flows consistent with § 203-10M of this article. Any capacity improvements must be designed to convey runoff from development of all areas tributary to the improvement consistent with the capacity criteria specified in § 203-10C of this article. By definition, a storm drainage problem area associated with the local runoff conveyance facilities indicates that adequate capacity does not exist.
(2)
Conditional No Detention II Districts. Within these districts, the capacity of the local runoff conveyance facilities must be calculated in the same manner as the Conditional No Detention I Districts. In this case, however, adequate capacity must be demonstrated from the site to the Lehigh River. After determining if adequate capacity exists, the developer shall use either no detention, a 100% release rate or provide capacity improvements as detained in Subsection B(1) of this section, Conditional No Detention I Districts.
(3)
Dual release rate districts. Within this district, the two year postdevelopment
runoff must be controlled to 30% of the predevelopment two-year runoff
peak. Further, the ten-, twenty-five- and one-hundred-year post-development
runoff must be controlled to 100% of the predevelopment peak.
A.
Any stormwater management controls required by this article and subject to a dual release rate criteria shall meet the applicable release rate criteria for each of the two-, ten-, twenty-five-, and one-hundred-year return period runoff events consistent with the calculation methodology specified in § 203-11 of this article.
B.
The exact location of the Stormwater Management District boundaries
as they apply to a given development site shall be determined by mapping
the boundaries using the two-foot topographic contours provided as
part of the drainage plan. The district boundaries as originally drawn
coincide with topographic divides or, in certain instances, are drawn
from the intersection of the watercourse and a physical feature such
as the confluence with another watercourse or a potential flow obstruction
(e.g., road, culvert, bridge, etc.). The physical feature is the downstream
limit of the subarea and the subarea boundary is drawn from that point
upslope to each topographic divide along the path perpendicular to
the contour lines.
C.
Any downstream capacity analysis conducted in accordance with this
article 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
increased 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 DEP Erosion and Sediment Pollution Control Program Manual (April
1990). Permissible velocities for selected channels are presented
in Appendix C (Part 21) of this article.[1]
[1]
Editor's Note: Appendix C is on file in the Borough offices.
(2)
Natural or man-made channels or swales must be able to convey the
increased 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 have sufficient capacity to pass or convey the increased flows associated with the twenty-five-year return period runoff event, except for facilities located within a designated floodplain area which must be capable of passing or conveying the one-hundred-year return period runoff. Any facilities which constitute stream enclosures per DEP Chapter 105 regulations shall be designed to convey the one-hundred-year return period runoff.
D.
For a proposed development site located within one release rate category
subarea, the total runoff from the site shall meet the applicable
release rate criteria. For development sites with multiple directions
of runoff discharge, individual drainage directions may be designed
for up to a 100% release rate so long as the total runoff from the
site is controlled to the applicable release rate.
E.
For a proposed development site located within two or more release
category subareas, the peak discharge rate from any subarea shall
be the predevelopment peak discharge for that subarea multiplied by
the applicable release rate. The calculated peak discharges shall
apply regardless of whether the grading plan changes the drainage
area by subarea. An exception to the above may be granted if discharges
from multiple subareas recombine in proximity to the site. In this
case, peak discharge in any direction may be a 100% release rate;
provided, that the overall site discharge meets the weighted average
release rate.
F.
For a proposed development site located partially within a release
rate category subarea and partially within a conditional no detention
subarea, in no event shall a significant portion of the site area
subject to the release rate control be drained to the discharge point(s)
located in the no detention subarea.
G.
Within a release rate category area, for a proposed development site
which has significant areas which drain to a closed depression(s),
the design release from the site will be the lesser of:
H.
Off-site areas which drain through a proposed development site are
not subject to release rate criteria when determining allowable peak
runoff rates. However, on-site drainage facilities shall be designed
to safely convey off-site flows through the development site.
I.
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 release rate criteria.
J.
Development proposals which, through groundwater recharge or other
means, do not increase the rate or volume of runoff discharged from
the site are not subject to the release rate provisions of this article.
K.
No harm option.
(1)
For any proposed development site not located in a conditional no detention district, the developer has the option of using a less restrictive runoff control (including no detention) if the developer can provide that no harm would be caused by discharging at a higher runoff rate than that specified by the plan. Proof of no harm would have to be shown from the development site through the remainder of the downstream drainage network to the confluence of the creek with the Delaware River. Proof of no harm must be shown using the capacity criteria specified in Subsection C of this section if downstream capacity analysis is a part of the no harm justification.
(2)
Attempts to prove no harm based upon downstream peak flow versus
capacity analysis shall be governed by the following provisions:
(a)
The peak flow values to be used for downstream areas for the
design return period storms (two-, ten-, twenty-five-, and one-hundred-year)
shall be the values from the calibrated Penn State Runoff Models for
the for the Catasauqua Creed Watershed and the watersheds associated
with several unnamed creeks. For the Conditional No Detention II areas,
the PSU-IV peak flow values will be used. These flow values would
be supplied to the developer by the Borough Engineer upon request.
(b)
Any available capacity in the downstream conveyance system as
documented by a developer may be used by the developer only in proportion
to his development site acreage relative to the total upstream undeveloped
acreage from the identified capacity (i.e., if his site is 10% of
the upstream undeveloped acreage, he may use up to 10% of the documented
downstream available capacity).
(c)
Developer-processed runoff controls which would generate increased peak flow rates at storm drainage problem areas would, by definition, be precluded from successful attempts to prove no harm, except in conjunction with proposed capacity improvements for the problem areas consistent with Subsection M of this section.
L.
Regional detention alternatives. For certain areas within the study
area, it may be more cost-effective to provide one control facility
for more than one development site than to provide an individual control
facility for each development site. The initiative and funding for
any regional runoff control alternatives are the responsibility of
prospective developers. The design of any regional control basins
must incorporate reasonable development of the entire upstream watershed.
The peak outflow of a regional basin would be determined on a case-by-case
basis using the hydrologic model of the watershed consistent with
protection of the downstream watershed areas. Hydrologic model refers
to the calibrated version of the Penn State Runoff Model as developed
for the stormwater management plan.
M.
Capacity improvements.
(1)
In certain instances, primarily within the conditional no detention areas, local drainage conditions may dictate more stringent levels of runoff control than those based upon protection of the entire watershed. In these instances, if the developer could prove that it would be feasible to provide capacity improvements to relieve the capacity deficiency in the local drainage network, then the capacity improvements could be provided by the developer in lieu of runoff controls on the development site. Peak flow calculations are to be done assuming that the local watershed is in the existing condition and then assuming that the local watershed is developed per current zoning and using the specified runoff controls. Any capacity improvements would be designed using the larger of the above peak flows and the capacity criteria specified in Subsection C of this section. All new development in the entire subarea(s) within which the proposed developed site is located shall be assumed to implement the developer's proposed discharge control, if any.
(2)
Capacity improvements may also be provided as necessary to implement
any regional detention alternatives or to implement a modified no
harm option which proposed specific capacity improvements to provide
that a less stringent discharge control would not create any harm
downstream.
N.
Waiver of runoff control based on minimum additional impervious cover. Any proposed regulated activity, except those defined in § 203-5D(4) and (5) of this article, which would create 10,000 square feet or less of additional impervious cover would be exempt from meeting the runoff control provisions of this article. For developments which are to take place in stages, the entire development plan must be used in determining conformance with this criteria. Predevelopment impervious cover is that which is in place as of the effective date of this article. 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 development. Any postdevelopment areas which may be designed to initially be semipervious (e.g., gravel, crushed stone, porous pavement, etc.) shall be considered impervious areas for the purposes of waiver evaluation. Any semipervious predevelopment areas shall be considered pervious areas for purposes of waiver evaluation unless demonstrated otherwise by the applicant.
O.
Compatibility with NPDES requirements. Any proposed regulated activity
for which a permanent stormwater quality control detention basin is
required under the NPDES regulations shall use the more stringent
runoff control criteria between this article and the NPDES requirements.
A.
Stormwater runoff from all development sites shall be calculated
using either the rational method or the soil-cover-complex methodology.
B.
The design of any detention basin intended to meet the requirements
of this article shall be verified by routing the design storm hydrograph
through the proposed basin. For basins designed using the rational
method technique, the design hydrograph for routing shall be either
the Universal Rational Hydrograph or the modified rational method
trapezoidal hydrograph which maximizes detention volume.
C.
All stormwater detention facilities shall provide a minimum one-foot freeboard, measured to the invert of the emergency spillway, above the maximum pool elevation associated with the two-through-twenty-five-year runoff events. A 0.5 foot freeboard shall be provided above the maximum pool elevation of the one-hundred-year runoff event. The two-through-one-hundred-year storm events shall be controlled by the primary outlet structure. An emergency spillway for each basin shall be designed to pass the entire one-hundred-year return frequency storm peak flow rate with a minimum 0.5 foot freeboard measured to the top of basin. The spillway should function to control overflows in the event of a complete blockage of the basin outlet system. If this detention facility is considered to be a dam as per DEP Chapter 105, the design of the facility must be consistent with the Chapter 105 regulations, and may be required to pass a storm greater than the one-hundred-year event.
D.
The minimum circular orifice diameter for controlling discharge rates
from detention facilities shall be three inches; provided, that as
much of the site runoff as practical is directed to the detention
facilities.
E.
Type II twenty-four-hour rainfall distribution.
(1)
All calculations using the soil-cover-complex method shall use the
Natural Resources Conservation Service Type II twenty-four-hour rainfall
distribution. The twenty-four-hour rainfall depths for the various
return periods to be used consistent with this article are taken from
the "PennDOT Intensity — Duration — Frequency Field Manual
(May 1986)" for Region 4:
|
Return Period
|
24 Hour Rainfall Depth
(inches)
| |
|---|---|---|
|
1 year
|
2.40
| |
|
2 years
|
3.00
| |
|
5 years
|
3.60
| |
|
10 years
|
4.56
| |
|
25 years
|
5.52
| |
|
50 years
|
6.48
| |
|
100 years
|
7.44
|
I.
Proposed volume controls shall be designed with sufficient storage
volume for a one-hundred-year return period event. The storage volume
shall equal or exceed the volume of the Universal Rational Hydrograph
for the drainage area to the volume control.
J.
All predevelopment calculations for a given discharge direction shall
be based on a common time of concentration considering both on-site
and off-site drainage areas. All postdevelopment calculations for
a given discharge direction shall be based on a common time of concentration
considering both on-site and any off-site drainage areas.
K.
The Manning equation shall be used to calculate the capacity of watercourses.
Manning 'n' values used in the calculations shall be consistent
with the table presented in Appendix C (Part 2I).[5] Pipe capacities shall be determined by methods acceptable
to the Borough Engineer.
[5]
Editor's Note: Appendix C is on file in the Borough offices.
L.
The Pennsylvania DEP, Chapter 105, Rules and Regulations, apply to the construction, modification, operation or maintenance of both existing and proposed dams, water obstructions and encroachments throughout the watershed. Criteria for design and construction of stormwater management facilities according to this article may not be the same criteria that are used in the permitting of dams under the Dam Safety Program.
For any of the regulated activities of this article, prior to
the final approval of subdivision and/or land development plans, or
the issuance of any permit, or the commencement of any land disturbance
activity, the owner, subdivider, developer or his agent shall submit
a drainage plan for approval.
A.
Impervious cover. Any regulated activity which would create 10,000
square feet or less of additional impervious cover is exempt from
the drainage plan preparation provisions of this article. This criteria
shall apply to the total proposed development even if development
is to take place in stages (i.e., the impervious cover associated
with the total development shall be used to compare to the waiver
minimum, not merely the individual stage impervious cover). Predevelopment
impervious cover is that which is in place as of the effective date
of this article. 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 areas designed to initially be gravel, crushed stone,
porous pavement, etc., shall be assumed to be impervious for the purposes
of comparison to the waiver criteria.
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 Borough prior to the effective date of this article is exempt
from the drainage plan preparation provisions of this article; provided,
that the approved drainage plan included design of stormwater facilities
consistent with ordinance provision in effect at the time of approval.
If significant revisions are made to the drainage plan after both
the preliminary plan approval and the effective date of this article,
preparation of a new drainage plan, subject to the provisions of this
article, shall be required.
The following items shall be included in the drainage plan:
B.
Map(s) of the project area showing:
(1)
The location of the project relative to highways, municipalities
or other identifiable landmarks.
(2)
Existing contours at intervals of two feet. In areas of steep slopes
(greater than 15%), five-foot contour intervals may be used. Off-site
drainage areas impacting the project including topographic detail.
(3)
Streams, lakes, ponds or other bodies of water within the project
areas.
(4)
Other physical features including existing drainage swales, wetlands,
closed depressions, sinkholes and areas of natural vegetation to be
preserved.
(5)
Locations of proposed underground utilities, sewers and water lines.
(6)
An overlay showing soil types and boundaries based on the Lehigh
or Northampton County Soil Survey latest edition, as applicable.
(7)
Proposed changes to land surface and vegetative cover.
(8)
Proposed structures, roads, paved areas and buildings.
(9)
Final contours at intervals of two feet. In areas of steep slopes
(greater than 15%), five-foot contour intervals may be used.
(10)
Stormwater management district boundaries applicable to the
site.
C.
Stormwater management controls.
(1)
All stormwater management controls must be shown on a map and described,
including:
(a)
Groundwater recharge methods such as seepage pits, beds or trenches.
When these structures are used, the locations of septic tank infiltration
areas and wells must be shown.
(b)
Other control devices or methods such as rooftop storage, semipervious
paving materials, grass swales, parking lot ponding, vegetated strips,
detention or retention ponds, storm sewers, etc.
(2)
All calculations, assumptions and criteria used in the design of
the control device or method must be shown.
D.
Maintenance program. A maintenance program for all stormwater management
control facilities must be included. This program must include the
proposed ownership of the control facilities, the maintenance requirements
for the facilities and the financial responsibilities for the required
maintenance.
A.
C.
(1)
The drainage plan shall be submitted by the developer to the Joint Planning Commission for coordination with the DEP permit application process under Chapter 105 (Dam Safety and Waterway Management) or Chapter 106 (Floodplain Management) of DEP's rules and regulations.
(2)
One copy of the drainage plan shall be submitted.
A.
The Borough Engineer shall review the drainage plan for consistency with the adopted Catasauqua Creek Watershed and Lehigh River Subbasin 4 Stormwater Management Plan as embodied by this article and against any additional storm drainage provisions contained in Chapter 215, Subdivision and Land Development, or Chapter 250, Zoning, as applicable.
B.
The Joint Planning Commission shall provide an advisory review of
the drainage plan for consistency with the Catasauqua Creek Watershed
and Lehigh River Subbasin 4 Stormwater Management Plan.
C.
For regulated activities specified in § 203-5D(1) and (2), the JPC shall provide written comments to the Borough, within a time frame consistent with established procedures under the Municipalities Planning Code, as to whether the drainage plan has been found to be consistent with the stormwater management plan.
E.
The Borough shall not approve any subdivision or land development [regulated activities § 203-5D(1) and (2)] or building permit application [regulated activities § 203-5(3) and (4)] if the drainage plan has been found to be inconsistent with the stormwater management plan as determined by the Borough Engineer.
A modification to a submitted drainage plan for a proposed development site which involves a change in control methods or techniques, or which involves the relocation or redesign of control measures, or which is necessary because soil or other conditions are not as stated on the drainage plan (as determined by the Borough Engineer) shall require a resubmission of the modified drainage plan consistent with § 203-15 subject to review per § 203-16 of this article.
A.
The Borough Council may hear requests for waivers where it is alleged
that the provisions of this article (Act 167)[1] inflict unnecessary hardship upon the applicant. The waiver
request shall be in writing on an application form promulgated by
the Borough and accompanied by the requisite fee based upon a fee
schedule adopted by the Borough. A copy of the completed application
form shall be provided to each of the following: Borough, Borough
Engineer, Borough Solicitor and Joint Planning Commission. The application
shall fully document the nature of the alleged hardship.
[1]
Editor's Note: See 32 P.S. § 680.1 et seq.
B.
The Borough may grant a waiver; provided, that all of the following
findings are made in a given case:
(1)
There are unique physical circumstances or conditions, including
irregularity of lot size or shape, or exceptional topographical or
other physical conditions peculiar to the particular property, and
that the unnecessary hardship is due to such conditions and not the
circumstances or conditions generally created by the provisions of
this article in the Stormwater Management District in which the property
is located.
(2)
Because of such physical circumstances or conditions, there is no
possibility that the property can be developed in strict conformity
with the provisions of this article, including the no harm provision
and that the authorization of a waiver is therefore necessary to enable
the reasonable use of the property.
(3)
Such unnecessary hardship has not been created by the applicant.
(4)
The waiver, if authorized, will represent the minimum waiver that
will afford relief and will represent the least modification possible
of the regulation in issue.
C.
In granting any waiver, the Borough Council may attach such reasonable
conditions and safeguards as it may deem necessary to implement the
purposes of Act 167 and this article.
A.
The Borough Engineer or his designee shall inspect all phases of
the installation of the permanent stormwater control facilities and
the completed installation.
B.
If at any stage of the work the Borough Engineer determines that the permanent stormwater control facilities are not being installed in accordance with the approved development plan, the Borough shall revoke any existing permits until a revised development plan is submitted and approved as required by § 203-17 of this article.
A fee shall be established by the Borough to defer Borough costs
for drainage plan review and processing.
The fees required by this article shall at a minimum cover:
A.
The review of the drainage plan by the Borough Engineer.
B.
The site inspection.
C.
The inspection of required controls and improvements during construction.
D.
The final inspection upon completion of the controls and improvements
required in the plan.
E.
Any additional work required to enforce any permit provisions, regulated
by this article, correct violations and assure the completion of stipulated
remedial actions.
F.
Administrative and clerical costs.
The maintenance responsibilities for permanent stormwater runoff
control facilities shall be determined based upon the type of ownership
of the property which is controlled by the facilities.
A.
Single-entity ownership. In all cases where the permanent stormwater
runoff control facilities are designed to manage runoff from property
in a single-entity ownership as defined below, the maintenance responsibility
for the stormwater control facilities shall be with the single-entity
owner. The single-entity owner shall enter into an agreement with
the Borough which specifies that the owner will properly maintain
the facilities consistent with accepted practice as determined by
the Borough Engineer. The agreement shall provide for regular inspections
by the Borough and contain such provisions as necessary to ensure
timely correction of any maintenance deficiencies by the single entity
owner. A single entity shall be defined as an individual, association,
public or private corporation, partnership, firm, trust, estate or
any other legal entity empowered to own real estate.
B.
Multiple ownership.
(1)
In cases where the property controlled by the permanent stormwater
control facilities shall be in multiple ownership (i.e., many individual
owners of various portions of the property), the developer shall dedicate
the permanent stormwater control facilities to the Borough for maintenance.
The developer shall pay a fee to the Borough corresponding to the
present worth of maintenance of the facilities in perpetuity. The
estimated annual maintenance cost for the facilities shall be based
on a fee schedule provided by the Borough Engineer and adopted by
the Borough. The fee schedule must be reasonable.
(2)
In certain multiple-ownership situations, the Borough may benefit
by transferring the maintenance responsibility to an individual or
group of individuals residing within the controlled area. These individuals
may have the permanent stormwater control facilities adjacent to their
lots or otherwise have an interest in the proper maintenance of the
facilities. In these instances, the Borough and the individual(s)
may enter into a formal agreement for the maintenance of the facilities.
The Borough shall maintain ownership of the facilities and be responsible
for periodic inspections.
Upon proper presentation of proper credentials, duly authorized
representatives of the Borough may enter at reasonable times upon
any property with the Borough to investigate or ascertain the condition
of the subject property in regard to any aspect regulated by this
article.
In the event that a person fails to comply with the requirements
of this article, or fails to conform to the requirements of any permit
issued hereunder, the Borough shall provide written notification of
the violation. Such notification shall set forth the nature of the
violation(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 provisions of this article. All such penalties shall
be deemed cumulative and resort by the Borough from pursuing any and
all other remedies. It shall be the responsibility of the owner of
the real property on which the regulated activity is proposed to occur,
is occurring, or has occurred to comply with the terms and conditions
of this article.
Any person found by the Borough to have violated any provision
of this article shall be subject to the enforcement provisions of
Article V of the Pennsylvania Municipalities Planning Code and/or
§ 15 of the Pennsylvania Stormwater Management Act (Act
167).[1]
[1]
Editor's Note: See 53 P.S. § 10501 et seq. and 32
P.S. § 680.1 et seq., respectively.
[Adopted 5-3-2007 by Ord. No. 1148]
This article shall be known and may be cited as the "Hokendauqua
Creek and Lehigh River Sub-Basins Watershed Act 167 Stormwater Management
Ordinance."
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 of the people of the commonwealth, their resources and the
environment.
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 quality.
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).[1]
[1]
Note: These provisions are from the DEP Guidance on MS4 Ordinance
Provisions and are not required for municipalities not subject to
the NPDES Phase II regulations.
F.
Nonstormwater discharges to municipal separate storm sewer systems
can contribute to pollution of waters of the commonwealth by the municipality.
The purpose of this article is to promote the public health, safety and welfare within the Hokendauqua Creek and Lehigh River Sub-Basins Watershed by minimizing the damages and maximizing the benefits described in § 203-27 of this article by provisions designed to:
A.
Manage stormwater runoff impacts at their source by regulating activities
which cause such problems.
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 municipality.
G.
Provide review procedures and performance standards for stormwater
planning, design and management.
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.
The municipality is empowered to regulate these activities by
the authority of the Act of October 4, 1978, P.L. 864 (Act 167), 32
P.S. § 680.1 et seq., as amended, the Stormwater Management
Act, and the Borough Code.[1]
[1]
Editor's Note: See 53 P.S. § 45101 et seq.
This article shall only apply to those areas of the municipality
which are located within the Hokendauqua Creek and Lehigh River Sub-basins
Watershed(s) as delineated on an official map available for inspection
at the municipal office. A map of the Hokendauqua Creek and Lehigh
River Sub-basins Watershed(s) at a reduced scale is included in Appendix
A for general reference. [Municipalities subject to the NPDES Phase
II regulations must ensure that all of the ordinance provisions required
to meet the MS4 NPDES requirements apply across the entire municipality.]
The following activities are defined as regulated activities and shall
be governed by this article:
A.
Land development.
B.
Subdivision.
C.
Construction of new or additional impervious surfaces (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 of stormwater systems or appurtenances thereto.
A.
Impervious cover. Any proposed regulated activity, except those defined in § 203-30E and F, which would create 10,000 square feet or less of additional impervious cover, is exempt from the drainage plan preparation provisions of this article. All of the impervious cover added incrementally to a site above the initial 10,000 square feet shall be subject to the drainage plan preparation provisions of this article. 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 article.
(1)
The date of the municipal ordinance adoption of the original Hokendauqua
Creek and Lehigh River Sub-basins Act 167 Stormwater Management Ordinance
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.
(2)
For development taking place in stages, the entire development plan
must be used in determining conformance with these criteria.
(3)
Additional impervious cover shall include, but not be limited to,
additional indoor living spaces, decks, patios, garages, driveways,
storage sheds and similar structures, any roof, parking or driveway
areas and any new streets and sidewalks constructed as part of or
for the proposed regulated activity.
(4)
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.
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 article is exempt from the drainage plan preparation provisions of this article, except as cited in Subsection C provided that the approved drainage plan included design of stormwater facilities to control runoff from the site currently proposed for regulated activities consistent with ordinance provisions in effect at the time of approval and the approval has not lapsed under the Municipalities Planning Code.[1] If significant revisions are made to the drainage plan
after both the preliminary plan approval and the effective date of
this article, preparation of a new drainage plan, subject to the provisions
of this article, 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.
[1]
Editor's Note: See 53 P.S. § 10101 et seq.
C.
These exemptions shall not relieve the applicant from implementing
such measures as are necessary to protect health, safety, property,
and state water quality requirements. These measures include adequate
and safe conveyance of stormwater on the site and as it leaves the
site. These exemptions do not relieve the applicant from the responsibility
to secure required permits or approvals for activities regulated by
any other applicable code, rule, act or ordinance.
Approvals issued pursuant to this article 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.
Notwithstanding any provisions of this article, 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 article, certain terms and words used
herein shall be interpreted as follows:
A.
Words used in the present tense include the future tense; the singular
number includes the plural, and the plural number includes the singular;
words of masculine gender include feminine gender; and words of feminine
gender include masculine gender.
B.
The word "includes" or "including" shall not limit the term to the
specific example but is intended to extend its meaning to all other
instances of like kind and character.
C.
The words "shall" and "must" are mandatory; the words "may" and "should"
are permissive.
As used in this article, the following terms shall have the
meanings indicated:
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 processes alone.
Activities, facilities, measures or procedures used to manage stormwater quantity and quality impacts from the regulated activities listed in § 203-30, to meet state water quality requirements, to promote groundwater recharge and to otherwise meet the purposes of this article.
Documentation, included as part of a drainage plan, detailing
the proposed BMPs, how they will be operated and maintained and who
will be responsible.
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.
STREAMSIDE BUFFERA zone of variable width located along a stream that is vegetated and is designed to filter pollutants from runoff.
SPECIAL GEOLOGIC FEATURE BUFFERA 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.
Stormwater management techniques such as cisterns and rain
barrels which direct runoff into storage devices, surface or subsurface,
for later reuse, 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 noninfiltration
BMPs.
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.
An underground reservoir or tank for storing rainwater.
A distinctive bowl-shaped depression in the land surface.
It is characterized by internal drainage, varying magnitude, and an
unbroken ground surface.
The Lehigh or Northampton County Conservation District, as
applicable.
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 vegetation.
A pipe, conduit or similar structure including appurtenant
works which carries surface water.
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 Pennsylvania Department of Environmental Protection.
The depth and time distribution of precipitation from a storm
event measured in probability of occurrence (e.g., one-hundred-year
storm) and duration (e.g., twenty-four-hour) and used in computing
stormwater management control systems.
A basin designed to retard stormwater runoff by temporarily
storing the runoff and releasing it at the appropriate release rate.
A person, partnership, association, corporation or other
entity, or any responsible person therein or agent thereof, that undertakes
any regulated activity of this article.
The specific tract of land for which a regulated activity
is proposed.
See "sheet flow."
A right granted by a landowner to a grantee, allowing the
use of private land for stormwater management purposes.
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 § 203-45.
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 removal of soil particles by the action of water, wind,
ice, or other geological agents.
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).
Man-made deposits of natural soils or rock products and waste
materials.
See "vegetated buffers."
The incremental depth in a stormwater management structure,
provided as a safety factor of design, above that required to convey
the design runoff event.
Replenishment of existing natural underground water supplies.
A written request for a waiver alleging that the provisions
of this article inflict unnecessary hardship upon the applicant. A
hardship waiver does not apply to and is not available from the water
quality provisions of this article and should not be granted.
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 § 203-39P.
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 U.S. 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.
A surface which prevents the percolation of water into the
ground.
A practice designed to direct runoff into the ground, e.g.,
French drain, seepage pit, seepage trench or bioretention area.
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.
Any of the following activities:
The improvement of one lot or two or more contiguous lots, tracts
or parcels of land for any purpose involving:
A group of two or more residential or nonresidential buildings,
whether proposed initially or cumulatively, or a single nonresidential
building on a lot or lots, regardless of the number of occupants or
tenure; or
The division or allocation of land or space, whether initially
or cumulatively, between or among two or more existing or prospective
occupants by means of, or for the purpose of streets, common areas,
leaseholds, condominiums, building groups or other features.
A subdivision of land.
Development in accordance with Section 503(1.1) of the Pennsylvania
Municipalities Planning Code.[1]
The ratio of the land area draining to the system, as modified by the weighting factors in § 203-42B, compared to the base area of the infiltration system.
Any natural channel or man-made conveyance system which has
the purpose of transporting runoff from the site to the main stem.
A development approach that promotes practices that will
minimize postdevelopment 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.
Any stream segment or other conveyance used as a reach in
the Hokendauqua Creek and Lehigh River Sub-basins hydrologic model.
A method for calculation of velocity of flow (e.g., feet
per second) and flow rate (e.g., cubic feet per second) in open channels
based upon channel shape, roughness, depth of flow and slope. "Open
channels" may include closed conduits so long as the flow is not under
pressure.
A 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.
Site design practices 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 postdevelopment. 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.
Borough of North Northampton, Lehigh or Northampton County
(as applicable), Pennsylvania.
U.S. Department of Agriculture (formerly the Soil Conservation
Service).
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.
National Pollutant Discharge Elimination System.
A structural mechanism designed to remove free oil and grease
(and possibly solids) from stormwater runoff.
"Point source" as described in 40 CFR 122.2 at the point
where the municipality's storm sewer system discharges to surface
waters of the commonwealth.
One with an interest in and often dominion over a property.
The maximum rate of flow of stormwater runoff at a given
location and time resulting from a specified storm event.
The computer-based hydrologic modeling technique adapted
to each watershed for the Act 167 Plans. The model was calibrated
to reflect actual flow values by adjusting key model input parameters.
An individual, partnership, public or private association
or corporation, firm, trust, estate, municipality, governmental unit,
public utility or any other legal entity whatsoever which is recognized
by law as the subject of rights and duties.
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.
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.[2]
A person who owns or operates a public water system.
A system which provides water to the public for human consumption
which has at least 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.)
A licensed professional geologist or a licensed professional
engineer who has a background or expertise in geology or hydrogeology.
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[3]), "i" is the rainfall intensity in inches per hour, and
"A" is the area of the tract in acres.
Any of the natural or man-made runoff conveyance channels
used for watershed runoff modeling purposes to connect the subareas
and transport flows downstream.
The portion of the water quality volume (WQv) used to maintain groundwater recharge rates at development sites (see § 203-39J).
Actions or proposed actions which impact upon proper management of stormwater runoff and which are governed by this article as specified in § 203-30.
Earth disturbance activity other than agricultural plowing
or tilling of one acre or more with a point source discharge to surface
waters or to the municipality's storm sewer system or earth disturbance
activity of five acres or more, regardless of the planned runoff.
This includes earth disturbance on any portion of, part or during
any stage of a larger common plan of development.
The percentage of the predevelopment peak rate of runoff
for a development site to which the postdevelopment peak rate of runoff
must be controlled to avoid peak flow increases throughout the watershed.
The average interval in years over which an event of a given
magnitude can be expected to recur. For example, the twenty-five-year
return period rainfall or runoff event would be expected to recur
on the average once every 25 years.
Earth disturbance activities within the existing road cross-section
such as grading and repairing existing unpaved road surfaces, cutting
road banks, cleaning or clearing drainage ditches and other similar
activities.
That part of precipitation which flows over the land.
Chambers which provide storage below the outlet in a storm
inlet to collect sediment, debris and associated pollutants, typically
requiring periodic cleanout.
An area of excavated earth filled with loose stone or similar
material and into which surface water is directed for infiltration
into the ground.
A conveyance or system of conveyances (including roads with
drainage systems, municipal streets, catch basins, curbs, gutters,
ditches, man-made channels or storm drains) primarily used for collecting
and conveying stormwater runoff.
Stormwater runoff flowing in a thin layer over the ground
surface.
A method of runoff computation developed by NRCS which is
based upon relating soil type and land use/cover to a runoff parameter
called a "curve number."
Carbonate bedrock features, including but not limited to
closed depressions, existing sinkholes, fracture traces, lineaments,
joints, faults, caves, pinnacles and geologic contacts between carbonate
and noncarbonate bedrock which may exist and must be identified on
a site when stormwater management BMPs are being considered.
A program that identifies procedures for preventing and,
as needed, cleaning up potential spills and makes such procedures
known and the necessary equipment available to appropriate personnel.
As defined under state regulations; protection of designated
and existing uses (see 25 Pa. Code Chapters 93 and 96), including:
Each stream segment in Pennsylvania has a "designated use,"
such as "cold water fishes" or "potable water supply," which is listed
in Chapter 93. These uses must be protected and maintained under state
regulations.
"Existing uses" are those attained as of November 1975, regardless
of whether they have been designated in Chapter 93. Regulated earth
disturbance activities must be designed to protect and maintain existing
uses and maintain the level of water quality necessary to protect
those uses in all streams, and to protect and maintain water quality
in special protection streams.
Water quality involves the chemical, biological and physical
characteristics of surface water bodies. After regulated earth disturbance
activities are complete, these characteristics can be impacted by
addition of pollutants such as sediment, and changes in habitat through
increased flow volumes and/or rates as a result of changes in land
surface area from those activities. Therefore, permanent discharges
to surface waters must be managed to protect the stream bank, streambed
and structural integrity of the waterway, to prevent these impacts.
A method of routing or moving an inflow hydrograph through
a reservoir or detention structure. The method solves the mass conservation
equation to determine an outflow hydrograph as it leaves the storage
facility.
Areas which lack adequate stormwater collection and/or conveyance
facilities and which present a hazard to persons or property. These
areas are either documented in Appendix B of this article or identified
by the municipality or municipal engineer.
A system of pipes or other conduits which carries intercepted
surface runoff, street water and other wash waters, or drainage, but
excludes domestic sewage and industrial wastes.
The surface runoff generated by precipitation reaching the
ground surface.
Any number of structural mechanisms such as multi-chamber
catch basins, sand/peat filters, sand filters, and so forth, which
are installed to intercept stormwater flow and remove pollutants prior
to discharge. Typically, these systems require periodic maintenance
and cleanout.
The plan for managing stormwater runoff adopted by Lehigh
and/or Northampton County for the Hokendauqua Creek and Lehigh River
Sub-basins Watershed as required by the Act of October 4, 1978, P.L.
864, (Act 167), as amended, and known as the "Stormwater Management
Act."[4]
A watercourse.
The smallest unit of watershed breakdown for hydrologic modeling
purposes for which the runoff control criteria have been established
in the stormwater management plan.
The division or redivision of a lot, tract or parcel of land
by any means into two or more lots, tracts, parcels or other divisions
of land, including changes in existing lot lines for the purpose,
whether immediate or future, of lease, partition by the court for
distribution to heirs or devisees, transfer of ownership or building
or lot development; provided, however, that the subdivision by lease
of land for agricultural purposes into parcels of more than 10 acres,
not involving any new street or easement of access or any residential
dwelling, shall be exempted.
Any and all rivers, streams, creeks, rivulets, impoundments,
ditches, watercourses, storm sewers, lakes, dammed water, wetlands,
ponds, springs and all other bodies or channels of conveyance of surface
water, or parts thereof, whether natural or artificial, within or
on the boundaries of this commonwealth.
A low-lying stretch of land which gathers or carries surface
water runoff. See also "vegetated swale."
The report written by Cahill Associates that addresses the
feasibility of infiltration in carbonate bedrock areas in the Little
Lehigh Creek Watershed. The report is available at the Lehigh Valley
Planning Commission offices.
Racks, screens or other similar devices installed in a storm
drainage system to capture coarse pollutants (trash, leaves, etc.).
Gently sloping areas that convey stormwater as sheet flow
over a broad, densely vegetated earthen area, possibly coupled with
the use of level spreading devices. Vegetated buffers should be situated
on minimally disturbed soils, have low-flow velocities and extended
residence times.
Vegetated systems installed on roofs that generally consist
of a waterproof layer, a root-barrier, drainage layer (optional),
growth media, and suitable vegetation. Vegetated roofs store and eventually
evapotranspirate the collected rooftop rainfall; overflows may be
provided for larger storms.
Vegetated earthen channels designed to convey stormwater. These
swales are not considered to be water quality BMPs.
Broad, shallow, densely vegetated, earthen channels designed
to treat stormwater while slowly infiltrating, evapotranspirating,
and conveying it. Swales should be gently sloping with low flow velocities
to prevent erosion. Check dams may be added to enhance performance.
Any channel of conveyance of surface water having defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
Any number of commercially available devices that are inserted
into storm inlets to capture sediment, oil, grease, metals, trash,
debris, etc.
The volume needed to capture and treat 90% of the average annual rainfall volume (see § 203-39B).
The entire region or area drained by a river or other body
of water, whether natural or artificial.
Basins that provide for necessary stormwater storage as well
as a permanent pool of water. To be successful, wet ponds 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)
and must be able to support a healthy aquatic community so as to avoid
creation of mosquito and other health and nuisance problems.
A.
All regulated activities in the municipality shall be subject to
the stormwater management requirements of this article.
B.
Storm drainage systems shall be provided to permit unobstructed flow
in natural watercourses except as modified by stormwater detention
facilities, recharge facilities, water quality facilities, pipe systems
or open channels consistent with this article.
C.
The existing locations of concentrated drainage discharge onto adjacent
property shall not be altered without written approval of the affected
property owner(s).
D.
Areas of existing diffused drainage discharge onto adjacent property
shall be managed such that, at minimum, the peak diffused flow does
not increase in the general direction of discharge, except as otherwise
provided in this article. If diffused flow is proposed to be concentrated
and discharged onto adjacent property, the developer must document
that there are adequate downstream conveyance facilities to safely
transport the concentrated discharge to the point of predevelopment
flow concentration to the stream reach or otherwise prove that no
harm will result from the concentrated discharge. Areas of existing
diffused drainage discharge shall be subject to any applicable release
rate criteria in the general direction of existing discharge, whether
they are proposed to be concentrated or maintained as diffused drainage
areas.
E.
Where a site is traversed by watercourses other than those for which a one-hundred-year floodplain is defined by the municipality, there shall be provided drainage easements conforming substantially with the line of such watercourses. The width of any easement shall be adequate to provide for unobstructed flow of storm runoff based on calculations made in conformance with § 203-42 for the one-hundred-year return period runoff and to provide a freeboard allowance of 0.5 foot above the design water surface level. The terms of the easement shall prohibit excavation, the placing of fill or structures, and any alterations, which may adversely affect the flow of stormwater within any portion of the easement. Also, periodic maintenance of the easement to ensure proper runoff conveyance shall be required. Watercourses for which the one-hundred-year floodplain is formally defined are subject to the applicable municipal floodplain regulations.
F.
When it can be shown that, due to topographic conditions, natural
drainage swales on the site cannot adequately provide for drainage,
open channels may be constructed conforming substantially to the line
and grade of such natural drainage swales. Capacities of open channels
shall be calculated using the Manning Equation.
G.
Postconstruction BMPs shall be designed, installed, operated and
maintained to meet the requirements of the Clean Streams Law and implementing
regulations, including the established practices in 25 Pa. Code Chapter
102 and the specifications of this article as to prevent accelerated
erosion in watercourse channels and at all points of discharge.
H.
No earth disturbance activities associated with any regulated activities
shall commence until approval by the municipality of a plan which
demonstrates compliance with the requirements of this article.
J.
Infiltration for stormwater management is encouraged where soils
and geology permit, consistent with the provisions of this article
and, where appropriate, the Recommendation Chart for Infiltration
Stormwater Management BMPs in Carbonate Bedrock in Appendix D.[2]
[2]
Editor's Note: Appendix D is on file in the Borough offices.
The following permit requirements apply to certain regulated
and earth disturbance activities and must be met prior to commencement
of regulated and earth disturbance activities, as applicable:
A.
All regulated and earth disturbance activities subject to permit
requirements by DEP under regulations at 25 Pa. Code Chapter 102.
B.
Work within natural drainage ways subject to permit by DEP under
25 Pa. Code Chapter 102 and Chapter 105.
C.
Any stormwater management facility that would be located in or adjacent to surface waters of the commonwealth, including wetlands, subject to permit by DEP under 25 Pa. Code Chapter 105.
D.
Any stormwater management facility that would be located on a state
highway right-of-way or require access from a state highway shall
be subject to approval by the Pennsylvania Department of Transportation
(PennDOT).
A.
No regulated earth disturbance activities within the municipality
shall commence until approval by the municipality of an erosion and
sediment control plan for construction activities. Written approval
by DEP or a delegated County Conservation District shall satisfy this
requirement.
B.
An erosion and sediment control plan is required by DEP regulations
for any earth disturbance activity of 5,000 square feet or more under
Pa. Code § 102.4(b).
C.
A DEP NPDES Stormwater Discharges Associated with Construction Activities
Permit is required for regulated earth disturbance activities under
Pa. Code Chapter 92.
D.
Evidence of any necessary permit(s) for regulated earth disturbance
activities from the appropriate DEP regional office or County Conservation
District must be provided to the municipality before the commencement
of an earth disturbance activity.
E.
A copy of the erosion and sediment control plan and any permit, as
required by DEP regulations, shall be available at the project site
at all times.
A.
No regulated earth disturbance activities within the municipality
shall commence until approval by the municipality of a drainage plan
which demonstrates compliance with this article. This article provides
standards to meet NPDES permit requirements associated with construction
activities and MS4 permit requirements.
B.
The Water Quality Volume (WQv) shall be captured and treated. The
WQv shall be calculated two ways. First, WQv shall be calculated using
the following formula:
|
WQv = (c)(P)(A)/12
|
|
Where:
| ||||
|
WQv
|
=
|
Water quality volume in acre-feet
| ||
|
c
|
=
|
Rational Method postdevelopment runoff coefficient for the two-year
storm
| ||
|
P
|
=
|
1.25 inches
| ||
|
A
|
=
|
Area in acres of proposed regulated activity
| ||
|
Second, the WQv shall be calculated as the difference in runoff
volume from predevelopment to postdevelopment for the two-year return
period storm. The effect of closed depressions on the site shall be
considered in this calculation. The larger of these two calculated
volumes shall be used as the WQv to be captured and treated, except
that in no case shall the WQv be permitted to exceed 1.25 inches of
runoff over the site area. This standard does not limit the volume
of infiltration an applicant may propose for purposes of water quantity/peak
rate control.
|
C.
The WQv shall be calculated for each postdevelopment drainage direction
on a site for sizing BMPs. Site areas having no impervious cover and
no proposed disturbance during development may be excluded from the
WQv calculations and do not require treatment.
D.
If an applicant is proposing to use a dry extended detention basin,
wet pond, constructed wetland or other BMP that ponds water on the
land surface and may receive direct sunlight, the discharge from that
BMP must be treated by infiltration, a vegetated buffer, filter strip,
bioretention, vegetated swale or other BMP that provides a thermal
benefit to protect the high quality waters of the Hokendauqua Creek
and Lehigh River Sub-basins from thermal impacts.
E.
The WQv for a site as a result of the regulated activities must either be treated with infiltration or two acceptable BMPs such as those listed in Subsection O, except for minor areas on the periphery of the site that cannot reasonably be drained to an infiltration facility or other BMP.
F.
Infiltration BMPs shall not be constructed on fill unless the applicant
demonstrates that the fill is stable and otherwise meets the infiltration
BMP standards of this article.
G.
The applicant shall document the bedrock type(s) present on the site
from published sources. Any apparent boundaries between carbonate
and noncarbonate bedrock shall be verified through more detailed site
evaluations by a qualified geotechnical professional.
H.
For each proposed regulated activity in the watershed where an applicant
intends to use infiltration BMPs, the applicant shall conduct a preliminary
site investigation, including gathering data from published sources,
a field inspection of the site, a minimum of one test pit and a minimum
of two percolation tests, as outlined in Appendix G.[1] This investigation will determine depth to bedrock, depth
to the seasonal high water table, soil permeability and location of
special geologic features, if applicable. This investigation may be
done by a certified Sewage Enforcement Officer (SEO), except that
the location(s) of special geologic features shall be verified by
a qualified geotechnical professional.
[1]
Editor's Note: Appendix G is on file in the Borough offices.
I.
Sites where applicants intend to use infiltration BMPs must meet
the following criteria:
(1)
Depth to bedrock below the invert of the BMP greater than or equal
to two feet.
(2)
Depth to seasonal high water table below the invert of the BMP greater
than or equal to three feet; except for infiltration of residential
roof runoff where the seasonal high water table must be below the
invert of the BMP. (If the depth to bedrock is between two and three
feet and the evidence of the seasonal high water table is not found
in the soil, no further testing to locate the depth to seasonal high
water table is required.)
(4)
Setback distances or buffers as follows:
(a)
One hundred feet from water supply wells.
(b)
Fifteen feet downgradient or 100 feet upgradient from building
foundations; except for residential development where the required
set back is 15 feet downgradient or 40 feet upgradient from building
foundations.
(c)
Fifty feet from septic system drainfields; except for residential
development where the required setback is 25 feet from septic system
drainfields.
(d)
Fifty feet from a geologic contact with carbonate bedrock unless
a preliminary site investigation is done in the carbonate bedrock
to show the absence of special geologic features within 50 feet of
the proposed infiltration area.
(e)
One hundred feet from the property line unless documentation
is provided to show that all setbacks from existing or potential future
wells, foundations and drainfields on neighboring properties will
be met; except for one- and two-family residential dwellings where
the required setback is 40 feet, unless documentation is provided
to show that all setbacks from existing or potential future wells,
foundations and drainfields on neighboring properties will be met.
J.
For entirely noncarbonate sites, the Recharge Volume (REv) shall be infiltrated unless the applicant demonstrates that it is infeasible to infiltrate the REv for reasons of seasonal high water table, permeability rate, soil depth or setback distances; or except as provided in Subsection U.
(1)
The REv shall be calculated as follows:
|
REv = (0.25)*(I)/12
|
|
Where:
| |||
|
REv
|
=
|
Recharge Volume in acre-feet
| |
|
I
|
=
|
Impervious area in acres
| |
(2)
The preliminary site investigation described in Subsection H is required and shall continue on different areas of the site until a potentially suitable infiltration location is found or the entire site is determined to be infeasible for infiltration. For infiltration areas that appear to be feasible based on the preliminary site investigation, the additional site investigation and testing as outlined in Appendix G[3] shall be completed.
[3]
Editor's Note: Appendix G is on file in the Borough offices.
(3)
If an applicant proposes infiltration, the municipality may determine
infiltration to be infeasible if there are known existing conditions
or problems that may be worsened by the use of infiltration.
(5)
If it is not feasible to infiltrate the full REv, the applicant shall infiltrate that portion of the REv that is feasible based on the site characteristics. If none of the REv can be infiltrated, REv shall be considered as part of the WQv and shall be captured and treated as described in Subsection O.
(6)
If REv is infiltrated, it may be subtracted from the WQv required
to be captured and treated.
K.
In entirely carbonate areas, where the applicant intends to us infiltration BMPs, the preliminary site investigation described in Subsection H shall be conducted. For infiltration areas that appear feasible based on the preliminary site investigation, the applicant shall conduct the additional site investigation and testing as outlined in Appendix G.[4] The soil depth, percolation rate and proposed loading rate, each weighted as described in § 203-42, along with the buffer from special geologic features, shall be compared to the Recommendation Chart for Infiltration Stormwater Management BMPs in Carbonate Bedrock in Appendix D[5] to determine if the site is recommended for infiltration. In addition to the recommendation from Appendix D, the conditions listed in Subsection I are required for infiltration in carbonate areas. Applicants are encouraged to infiltrate the REv, as calculated in Subsection J, but are not required to use infiltration BMPs on a carbonate site even if the site falls in the "Recommended" range on the chart in Appendix D. Any amount of volume infiltrated can be subtracted from the WQv to be treated by noninfiltration BMPs. If infiltration is not proposed, the full WQv shall be treated by two acceptable BMPs, as specified in Subsection O.
L.
If a site has both carbonate and noncarbonate areas, the applicant shall investigate the ability of the noncarbonate portion of the site to fully meet this article to meet the requirements for REv for the whole site through infiltration. If that proves infeasible, infiltration in the carbonate area as described in Subsection K or two other noninfiltration BMPs as described in Subsection O must be used. No infiltration structure in the noncarbonate area shall be located within 50 feet of a boundary with carbonate bedrock, except when a preliminary site investigation has been done showing the absence of special geologic features within 50 feet of the proposed infiltration area.
M.
If infiltration BMPs are proposed in carbonate areas, the postdevelopment
two-year runoff volume leaving the site shall be 80% or more of the
predevelopment runoff volume for the carbonate portion of the site
to prevent infiltration of volumes far in excess of the predevelopment
infiltration volume.
N.
Site areas proposed for infiltration shall be protected from disturbance
and compaction except as necessary for construction of infiltration
BMPs.
O.
If infiltration of the entire WQv is not proposed, the remainder
of the WQv shall be treated by two acceptable BMPs in series for each
discharge location. Sheet flow draining across a pervious area can
be considered as one BMP. Sheet flow across impervious areas and concentrated
flow shall flow through two BMPs. If sheet flow from an impervious
area is to be drained across a pervious area as one BMP, the length
of the pervious area must be equal to or greater than the length of
impervious area. In no case may the same BMP be employed consecutively
to meet the requirement of this section. Acceptable BMPs are listed
below along with the recommended reference for design.
|
Best Management Practice
|
Design Reference Numbers
| |
|---|---|---|
|
BioretentionA
|
4, 5, 11, 16
| |
|
Capture/reuseB
|
4, 14
| |
|
Constructed wetlands
|
4, 5, 8, 10, 16
| |
|
Dry extended detention ponds
|
4, 5, 8, 12, 18
| |
|
Minimum disturbance/minimum maintenance practices
|
1, 9
| |
|
Significant reduction of existing impervious cover
|
N/A
| |
|
Stormwater filtersA (sand, peat,
compost, etc.)
|
4, 5, 10, 16
| |
|
Vegetated buffers/filter strips
|
2, 3, 5, 11, 16, 17
| |
|
Vegetated roofs
|
4, 13
| |
|
Vegetated swalesA
|
2, 3, 5, 11, 16, 17
| |
|
Water quality inletsD
|
4, 7, 15, 16, 19
| |
|
Wet detention ponds
|
4, 5, 6, 8
|
|
NOTES:
| ||
|---|---|---|
|
A
|
This BMP could be designed with or without an infiltration component.
If infiltration is proposed, the site and BMP will be subject to the
testing and other infiltration requirements in this article.
| |
|
B
|
If this BMP is used to treat the entire WQv, then it is the
only BMP required because of this BMPs superior water quality performance.
| |
|
C
|
See table below.
| |
|
D
|
Water quality inlets include such BMPs as oil/water separators,
sediment traps/catch basin sumps, and trash/debris collectors in catch
basins.
| |
|
Number
|
Design Reference Title
| |
|---|---|---|
|
1
|
"Conservation Design For Stormwater Management — A Design
Approach to Reduce Stormwater Impacts From Land Development and Achieve
Multiple Objectives Related to Land Use," Delaware Department of Natural
Resources and Environmental Control, The Environmental Management
Center of the Brandywine Conservancy, September 1997.
| |
|
2
|
"A Current Assessment of Urban Best Management Practices: Techniques
for Reducing Nonpoint Source Pollution in the Coastal Zone," Schueler,
T. R., Kumble, P. and Heraty, M., Metropolitan Washington Council
of Governments, 1992.
| |
|
3
|
"Design of Roadside Channels with Flexible Linings," Federal
Highway Administration, Chen, Y.H. and Cotton, G.K., Hydraulic Engineering
Circular 15, FHWA-IP-87-7, McLean Virginia, 1988.
| |
|
4
|
"Draft Stormwater Best Management Practices Manual," Pennsylvania
Department of Environmental Protection, January 2005.
| |
|
5
|
"Evaluation and Management of Highway Runoff Water Quality,"
Federal Highway Administration, FHWA-PD-96-032, Washington, D.C.,
1996.
| |
|
6
|
"Evaporation Maps of the United States," U.S. Weather Bureau
(now NOAA/National Weather Service) Technical Paper 37, Published
by Department of Commerce, Washington D.C., 1959.
| |
|
7
|
"Georgia Stormwater Manual," AMEC Earth and Environmental, Center
for Watershed Protection, Debo and Associates, Jordan Jones and Goulding,
Atlanta Regional Commission, Atlanta, Georgia, 2001.
| |
|
8
|
"Hydraulic Design of Highway Culverts," Federal Highway Administration,
FHWA HDS 5, Washington, D.C., 1985 (revised May 2005).
| |
|
9
|
"Low Impact Development Design Strategies An Integrated Design
Approach, Prince Georges County, Maryland Department of Environmental
Resources, June 1999.
| |
|
10
|
Maryland Stormwater Design Manual," Maryland Department of the
Environment, Baltimore, Maryland, 2000.
| |
|
11
|
"Pennsylvania Handbook of Best Management Practices for Developing
Areas," Pennsylvania Department of Environmental Protection, 1998.
| |
|
12
|
"Recommended Procedures for Act 167 Drainage Plan Design," LVPC,
Revised 1997.
| |
|
13
|
"Roof Gardens History, Design, and Construction," Osmundson,
Theodore. New York: W.W. Norton & Company, 1999.
| |
|
14
|
"The Texas Manual on Rainwater Harvesting," Texas Water Development
Board, Austin, Texas, Third Edition, 2005.
| |
|
15
|
"VDOT Manual of Practice for Stormwater Management," Virginia
Transportation Research Council, Charlottesville, Virginia, 2004.
| |
|
16
|
"Virginia Stormwater Management Handbook," Virginia Department
of Conservation and Recreation, Richmond, Virginia, 1999.
| |
|
17
|
"Water Resources Engineering," Mays, L.W., John Wiley &
Sons, Inc., 2005.
| |
|
18
|
"Urban Hydrology for Small Watersheds," Technical Report 55,
US Department of Agriculture, Natural Resources Conservation Service,
1986.
| |
|
19
|
U.S. EPA, Region 1 New England website (as of August 2005) http://www.epa.gov/NE/assistance/ceitts/stormwater/techs/html
|
P.
Stormwater runoff from hotspot land uses shall be pretreated. In no case may the same BMP be employed consecutively to meet this requirement and the requirement in Subsection O.
(1)
Acceptable methods of pretreatment are listed below.
|
Hotspot Land Use
|
Pretreatment Method(s)
| |
|---|---|---|
|
Vehicle maintenance and repair facilities, including auto parts
stores
|
Water quality inlets
Use of drip pans and/or dry sweep material under vehicles/equipment
Use of absorbent devices to reduce liquid releases
Spill prevention and response program
| |
|
Vehicle fueling stations
|
Water quality inlets
Spill prevention and response program
| |
|
Storage areas for public works
|
Water quality inlets
Use of drip pans and/or dry sweep material under vehicles/equipment
Use of absorbent devices to reduce liquid releases
Spill prevention and response program
Diversion of stormwater away from potential contamination areas
| |
|
Outdoor storage of liquids
|
Spill prevention and response program
| |
|
Commercial nursery operations
|
Vegetated swales/filter strips
Constructed wetlands
Stormwater collection and reuse
| |
|
Salvage yards and recycling facilities*
|
BMPs that are a part of a stormwater pollution prevention plan
under an NPDES permit
| |
|
Fleet storage yards and vehicle cleaning facilities*
|
BMPs that are a part of a stormwater pollution prevention plan
under an NPDES permit
| |
|
Facilities that store or generate regulated substances*
|
BMPs that are a part of a stormwater pollution prevention plan
under an NPDES permit
| |
|
Marinas*
|
BMPs that are a part of a stormwater pollution prevention plan
under an NPDES permit
| |
|
Certain industrial uses (listed under NPDES)*
|
BMPs that are a part of a stormwater pollution prevention plan
under an NPDES permit
|
|
NOTES:
| ||
|---|---|---|
|
*
|
Regulated under the NPDES Stormwater Program
| |
(2)
Design references for the pretreatment methods, as necessary, are
listed below. If the applicant can demonstrate to the satisfaction
of the municipality that the proposed land use is not a hotspot, then
the pretreatment requirement would not apply.
|
Pretreatment Method
|
Design ReferenceA
| |
|---|---|---|
|
Constructed wetlands
|
4, 5, 8, 10, 16
| |
|
Diversion of stormwater away from potential contamination areas
|
4, 11
| |
|
Stormwater collection and reuse (especially for irrigation)
|
4, 14
| |
|
Stormwater filters (sand, peat, compost, etc.)
|
4, 5, 10, 16
| |
|
Vegetated swales
|
2, 3, 5, 11, 16, 17
| |
|
Water quality inlets
|
4, 7, 15, 16, 19
|
|
NOTE:
| ||
|---|---|---|
|
A
|
These numbers refer to the Design Reference Title Chart in Subsection O above.
| |
Q.
The use of infiltration BMPs is prohibited on hotspot land use areas.
R.
Stormwater infiltration BMPs shall not be placed in or on a special
geologic feature(s). Additionally, stormwater runoff shall not be
discharged into existing on-site sinkholes.
S.
Applicants shall request, in writing, public water suppliers to provide the Zone 1 Wellhead Protection radius, as calculated by the method outlined in the Pennsylvania Department of Environmental Protection Wellhead Protection regulations, for any public water supply well within 400 feet of the site. In addition to the setback distances specified in Subsection I, infiltration is prohibited in the Zone I radius as defined and substantiated by the public water supplier in writing. If the applicant does not receive a response from the public water supplier, the Zone I radius is assumed to be 100 feet.
T.
The volume and rate of the net increase in stormwater runoff from
the regulated activities must be managed to prevent the physical degradation
of receiving waters from such effects as scour and streambank destabilization,
to satisfy state water quality requirements, by controlling the two-year
postdevelopment runoff to a 30% release rate.
U.
The municipality may, after consultation with DEP, approve alternative
methods for meeting the state water quality requirements other than
those in this section, provided that they meet the minimum requirements
of and do not conflict with state law including but not limited to
the Clean Streams Law.
A.
Mapping of stormwater management districts. To implement the provisions
of the Hokendauqua Creek and Lehigh River Sub-basins Watershed Stormwater
Management Plan, the municipality is hereby divided into stormwater
management districts consistent with the Hokendauqua Creek and Lehigh
River Sub-basins Release Rate Map presented in the plan update. The
boundaries of the stormwater management districts are shown on an
official map which is available for inspection at the municipal office.
A copy of the official map at a reduced scale is included in Appendix
A for general reference.[1]
[1]
Editor's Note: Appendix A is on file in the Borough offices.
B.
Description of stormwater management districts. Two types of stormwater
management districts may be applicable to the municipality, namely
Conditional/Provisional No Detention Districts and Dual Release Rate
Districts, as described below.
(1)
Conditional/Provisional No Detention Districts. Within these districts, the capacity of the "local" runoff conveyance facilities (as defined in § 203-35) must be calculated to determine if adequate capacity exists. For this determination, the developer must calculate peak flows, assuming that the site is developed as proposed and that the remainder of the local watershed is in the existing condition. The developer must also calculate peak flows, assuming that the entire local watershed is developed per current zoning and that all new development would use the runoff controls specified by this article. The larger of the two peak flows calculated will be used in determining if adequate capacity exists. If adequate capacity exists to safely transport runoff from the site to the main channel (as defined in § 203-35), these watershed areas may discharge postdevelopment peak runoff without detention facilities. If the capacity calculations show that the "local" runoff conveyance facilities lack adequate capacity, the developer shall either use a 100% release rate control or provide increased capacity of downstream elements to convey increased peak flows consistent with § 203-41P. Any capacity improvements must be designed to convey runoff from development of all areas tributary to the improvement consistent with the capacity criteria specified in § 203-41D. By definition, a storm drainage problem area associated with the "local" runoff conveyance facilities indicates that adequate capacity does not exist. Sites in these districts are still required to meet all of the water quality requirements in § 203-39.
(2)
Dual Release Rate Districts. Within these districts, the two-year
postdevelopment peak discharge must be controlled to 30% of the predevelopment
two-year runoff peak. Further, the ten-, twenty-five- and one-hundred-year
post development peak runoff must be controlled to the stated percentage
of the predevelopment peak. Release rates associated with the ten-
through one-hundred-year events vary from 50% to 100%, depending upon
location in the watershed. [For the Monocacy Creek and Nancy Run Watersheds,
the original Single Release Rate Districts become Dual Release Rate
Districts due to the channel protection standard requiring developments
to meet a two-year 30% release rate.]
A.
Applicants shall provide a comparative pre- and postconstruction
stormwater management hydrograph analysis for each direction of discharge
and for the site overall to demonstrate compliance with the provisions
of this article.
B.
Any stormwater management controls required by this article and subject to a dual release rate criteria shall meet the applicable release rate criteria for each of the two-, ten-, twenty-five- and one-hundred-year return period runoff events consistent with the calculation methodology specified in § 203-42.
C.
The exact location of the stormwater management district boundaries
as they apply to a given development site shall be determined by mapping
the boundaries using the two-foot topographic contours provided as
part of the drainage plan. The district boundaries as originally drawn
coincide with topographic divides or, in certain instances, are drawn
from the intersection of the watercourse and a physical feature such
as the confluence with another watercourse or a potential flow obstruction
(e.g., road, culvert, bridge, etc.). The physical feature is the downstream
limit of the subarea and the subarea boundary is drawn from that point
up slope to each topographic divide along the path perpendicular to
the contour lines.
D.
Any downstream capacity analysis conducted in accordance with this
article 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
increased runoff associated with a two-year return period event within
their banks at velocities consistent with protection of the channels
from erosion.
(2)
Natural or man-made channels or swales must be able to convey the
increased twenty-five-year return period runoff without creating any
hazard to persons or property.
E.
For a proposed development site located within one release rate category
subarea, the total runoff from the site shall meet the applicable
release rate criteria. For development sites with multiple directions
of runoff discharge, individual drainage directions may be designed
for up to a 100% release rate so long as the total runoff from the
site is controlled to the applicable release rate.
F.
For a proposed development site located within two or more release
category subareas, the peak discharge rate from any subarea shall
be the predevelopment peak discharge for that subarea multiplied by
the applicable release rate. The calculated peak discharges shall
apply regardless of whether the grading plan changes the drainage
area by subarea. An exception to the above may be granted if discharges
from multiple subareas recombine in proximity to the site. In this
case, peak discharge in any direction may be a 100% release rate,
provided that the overall site discharge meets the weighted average
release rate.
G.
For a proposed development site located partially within a release
rate category subarea and partially within a Conditional/Provisional
No Detention subarea, the size of the predevelopment drainage area
on a site may not be changed postdevelopment to create potentially
adverse conditions on downstream properties except as part of a "no
harm" or hardship waiver procedure.
H.
No portion of a site may be regraded between the Hokendauqua Creek
and Lehigh River Sub-basins Watershed and any adjacent watershed except
as part of a "no harm" or hardship waiver procedure.
I.
Within a release rate category area, for a proposed development site
which has areas which drain to a closed depression(s), the design
release from the site will be the lesser of: (a) the applicable release
rate flow assuming no closed depression(s); or (b) the existing peak
flow actually leaving the site. In cases where (b) would result in
an unreasonably small design release, the design discharge of less
than or equal to the release rate will be determined by the available
downstream conveyance capacity to the main channel calculated using
Section 306.D. and the minimum orifice criteria.
J.
Off-site areas which drain through a proposed development site are not subject to release rate criteria when determining allowable peak runoff rates. However, on-site drainage facilities shall be designed to safely convey off-site flows through the development site using the capacity criteria in Subsection D and the detention criteria in § 203-42.
K.
For development sites proposed to take place in phases, all detention
ponds shall be designed to meet the applicable release rate(s) applied
to all site areas tributary to the proposed pond discharge direction.
All site tributary areas will be assumed as developed, regardless
of whether all site tributary acres are proposed for development at
that time. An exception shall be sites with multiple detention ponds
in series where only the downstream pond must be designed to the stated
release rate.
L.
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 release rate criteria. The impact
area includes any proposed cover or grading changes.
M.
Development proposals which, through groundwater recharge or other
means, do not increase either the rate or volume of runoff discharged
from the site compared to predevelopment are not subject to the release
rate provisions of this article.
N.
"No harm" water quantity option. For any proposed development site not located in a Conditional/Provisional No Detention District, the developer has the option of using a less-restrictive runoff control (including no detention) if the developer can prove that special circumstances exist for the proposed development site and that "no harm" would be caused by discharging at a higher runoff rate than that specified by the plan. "Special circumstances" are defined as any hydrologic or hydraulic aspects of the development itself not specifically considered in the development of the plan runoff control strategy. Proof of no harm would have to be shown from the development site through the remainder of the downstream drainage network to the confluence of the creek with the Delaware or Lehigh River. Proof of no harm must be shown using the capacity criteria specified in Subsection D if downstream capacity analysis is a part of the no harm justification.
(1)
Attempts to prove "no harm" based upon downstream peak flow versus
capacity analysis shall be governed by the following provisions:
(a)
The peak flow values to be used for downstream areas for the
design return period storms (two-, ten-, twenty-five- and one-hundred-year)
shall be the values from the calibrated PSRM Model for the Hokendauqua
Creek and Lehigh River Sub-basins or as calculated by an applicant
using an alternate method acceptable to the municipality. The flow
values from the PSRM Model would be supplied to the developer by the
municipality upon request.
(b)
Any available capacity in the downstream conveyance system as
documented by a developer may be used by the developer only in proportion
to his development site acreage relative to the total upstream undeveloped
acreage from the identified capacity (i.e., if his site is 10% of
the upstream undeveloped acreage, he may use up to 10% of the documented
downstream available capacity).
(c)
Developer-proposed runoff controls which would generate increased peak flow rates at storm drainage problem areas would, by definition, be precluded from successful attempts to prove no harm, except in conjunction with proposed capacity improvements for the problem areas consistent with Subsection P.
O.
Regional detention alternatives. For certain areas within the study
area, it may be more cost-effective to provide one control facility
for more than one development site than to provide an individual control
facility for each development site. The initiative and funding for
any regional runoff control alternatives are the responsibility of
prospective developers. The design of any regional control basins
must incorporate reasonable development of the entire upstream watershed.
The peak outflow of a regional basin would be determined based on
the required release rate at the point of discharge.
P.
Capacity improvements.
(1)
In certain instances, primarily within the Conditional/Provisional No Detention areas, local drainage conditions may dictate more stringent levels of runoff control than those based upon protection of the entire watershed. In these instances, if the developer could prove that it would be feasible to provide capacity improvements to relieve the capacity deficiency in the local drainage network, then the capacity improvements could be provided by the developer in lieu of runoff controls on the development site. Peak flow calculations shall be done assuming that the local watershed is in the existing condition and then assuming that the local watershed is developed per current zoning and using the specified runoff controls. Any capacity improvements would be designed using the larger of the above peak flows and the capacity criteria specified in Subsection D. All new development in the entire subarea(s) within which the proposed development site is located shall be assumed to implement the developer's proposed discharge control, if any.
(2)
Capacity improvements may also be provided as necessary to implement
any regional detention alternatives or to implement a modified "no
harm" option which proposes specific capacity improvements to provide
that a less stringent discharge control would not create any harm
downstream.
A.
Stormwater runoff from all development sites shall be calculated
using either the rational method or the soil-cover-complex methodology.
B.
Infiltration BMP loading rate percentages in the Recommendation Chart
for Infiltration Stormwater Management BMPs in Carbonate Bedrock in
Appendix D[1] shall be calculated as follows:
|
Area tributary to infiltration BMP
Base area of infiltration BMP *100%
|
|
The area tributary to the infiltration BMP shall be weighted
as follows:
| ||
|
All disturbed areas to be made impervious: weight at 100%
| ||
|
All disturbed areas to be made pervious: weight at 50%
| ||
|
All undisturbed pervious areas: weight at 0%
| ||
|
All existing impervious areas: weight at 100%
| ||
[1]
Editor's Note: Appendix D is on file in the Borough offices.
C.
Soil thickness is to be measured from the bottom of any proposed
infiltration system.
(1)
The effective soil thickness in the Recommendation Chart for Infiltration
Stormwater Management BMPs in Carbonate Bedrock in Appendix D[2] is the measured soil thickness multiplied by the thickness
factor based on soil permeability (as measured by the adapted 25 Pa.
Code § 73.15 percolation test in Appendix G), as follows:
|
Permeability Range*
|
Thickness Factor
| |
|---|---|---|
|
6.0 to 12.0 inches/hour
|
0.8
| |
|
2.0 to 6.0 inches/hour
|
1.0
| |
|
1.0 to 2.0 inches/hour
|
1.4
| |
|
0.75 to 1.0 inches/hour
|
1.2
| |
|
0.5 to 0.75 inches/hour
|
1.0
|
|
NOTE:
| ||
|---|---|---|
|
*
|
If the permeability rate (as measured by the adapted 25 Pa.
Code § 73.15 percolation test in Appendix G) falls on a
break between two thickness factors, the smaller thickness factor
shall be used.
| |
[2]
Editor's Note: Appendix D is on file in the Borough offices.
(2)
Sites with soil permeability greater than 12.0 inches per hour or
less than 0.5 inch per hour, as measured by the adapted 25 Pa. Code
§ 73.15 percolation test in Appendix G, are not recommended
for infiltration.
D.
The design of any detention basin intended to meet the requirements
of this article shall be verified by routing the design storm hydrograph
through the proposed basin using the storage indication method or
other methodology demonstrated to be more appropriate. For basins
designed using the Rational Method technique, the design hydrograph
for routing shall be either the Universal Rational Hydrograph or the
Modified Rational Method trapezoidal hydrograph which maximizes detention
volume. Use of the Modified Rational hydrograph shall be consistent
with the procedure described in Section "PIPE.RAT" of the Users'
Manual for the Penn State Urban Hydrology Model (1987).
E.
BMPs designed to store or infiltrate runoff and discharge to surface
runoff or pipe flow shall be routed using the storage indication method.
F.
BMPs designed to store or infiltrate runoff and discharge to surface
runoff or pipe flow shall provide storage volume for the full WQv
below the lowest outlet invert.
G.
Wet detention ponds designed to have a permanent pool for the WQv
shall assume that the permanent pool volume below the primary outlet
is full at the beginning of design event routing for the purposes
of evaluating peak outflows.
H.
All stormwater detention facilities shall provide a minimum one-foot freeboard above the maximum pool elevation associated with the two- through twenty-five-year runoff events. A 0.5 foot freeboard shall be provided above the maximum pool elevation of the one-hundred-year runoff event. The freeboard shall be measured from the maximum pool elevation to the invert of the emergency spillway. The two- through one-hundred-year storm events shall be controlled by the primary outlet structure. An emergency spillway for each basin shall be designed to pass the one-hundred-year return frequency storm peak basin inflow rate with a minimum 0.5 foot freeboard measured to the top of basin. The freeboard criteria shall be met considering any offsite areas tributary to the basin as developed, as applicable. If this detention facility is considered to be a dam as per DEP Chapter 105, the design of the facility must be consistent with the Chapter 105 regulations, and may be required to pass a storm greater than the one-hundred-year event.
I.
The minimum circular orifice diameter for controlling discharge rates
from detention facilities shall be three inches. Designs where a lesser
size orifice would be required to fully meet release rates shall be
acceptable with a three-inch orifice, provided that as much of the
site runoff as practical is directed to the detention facilities.
The minimum three-inch diameter does not apply to the control of the
WQv.
J.
Runoff calculations using the soil-cover-complex method shall use
the Natural Resources Conservation Service Type II twenty-four-hour
rainfall distribution. The twenty-four-hour rainfall depths for the
various return periods to be used consistent with this article may
be taken from NOAA Atlas 14, Volume 2 Version 2.1, 2004 or the PennDOT
Intensity - Duration - Frequency Field Manual "PDT-IDF) (May 1986)
for Region 4.
(1)
The following values are taken from the PDT-IDF Field Manual:
|
Return Period
(years)
|
24-Hour Rainfall Depth
(inches)
| |
|---|---|---|
|
1
|
2.40
| |
|
2
|
3.00
| |
|
5
|
3.60
| |
|
10
|
4.56
| |
|
25
|
5.52
| |
|
50
|
6.48
| |
|
100
|
7.44
|
K.
Runoff calculations using the Rational Method shall use rainfall
intensities consistent with appropriate times of concentration and
return periods and NOAA Atlas 14, Volume 2, Version 2.1, 2004 or the
Intensity-Duration-Frequency Curves as presented in Appendix C.[4]
[4]
Editor's Note: Appendix C is on file in the Borough offices.
L.
Runoff Curve Numbers (CNs) to be used in the soil-cover-complex method
shall be based upon the matrix presented in Appendix C.
M.
Runoff coefficients for use in the Rational Method shall be based
upon the table presented in Appendix C.
N.
All time of concentration calculations shall use a segmental approach
which may include one or all of the flow types below:
(1)
Sheet flow (overland flow) calculations shall use either the NRCS
average velocity chart (Figure 3-1, Technical Release-55, 1975) or
the modified kinematic wave travel time equation (equation 3-3, NRCS
TR-55, June 1986). If using the modified kinematic wave travel time
equation, the sheet flow length shall be limited to 50 feet for designs
using the Rational Method and limited to 150 feet for designs using
the Soil-Cover-Complex method.
(2)
Shallow concentrated flow travel times shall be determined from the
watercourse slope, type of surface and the velocity from Figure 3-1
of TR-55, June 1986.
(4)
Pipe flow travel times shall be determined from velocities calculated
using the Manning Equation assuming full flow and the Manning 'n'
values from Appendix C.
O.
If using the Rational Method, all predevelopment calculations for
a given discharge direction shall be based on a common time of concentration
considering both on-site and any off-site drainage areas. If using
the Rational Method, all postdevelopment calculations for a given
discharge direction shall be based on a common time of concentration
considering both on-site and any off-site drainage areas.
P.
The Manning Equation shall be used to calculate the capacity of watercourses.
Manning 'n' values used in the calculations shall be consistent
with the table presented in Appendix C or other appropriate standard
engineering 'n' value resources. Pipe capacities shall be
determined by methods acceptable to the municipality.
Q.
The Pennsylvania DEP, Chapter 105, Rules and Regulations, apply to the construction, modification, operation or maintenance of both existing and proposed dams, water obstructions and encroachments throughout the watershed. Criteria for design and construction of stormwater management facilities according to this article may differ from the criteria that are used in the permitting of dams under the Dam Safety Program.
For any of the regulated activities of this article, prior to
the final approval of subdivision and/or land development plans, or
the issuance of any permit, or the commencement of any regulated earth
disturbance activity, the owner, subdivider, developer or his agent
shall submit a drainage plan and receive municipal approval of the
plan.
Exemptions from the drainage plan requirements are as specified in § 203-31.
The following items shall be included in the drainage plan:
B.
Map(s) of the project area showing:
(1)
The location of the project relative to highways, municipalities
or other identifiable landmarks.
(2)
Existing contours at intervals of two feet. In areas of steep slopes
(greater than 15%), five-foot contour intervals may be used. Off-site
drainage areas impacting the project including topographic detail.
(3)
Streams, lakes, ponds or other bodies of water within the project
area.
(4)
Other features including flood hazard boundaries, existing drainage
swales, wetlands, closed depressions, sinkholes and areas of natural
vegetation to be preserved.
(5)
Locations of proposed underground utilities, sewers and water lines.
The locations of all existing and proposed utilities, sanitary sewers
and water lines within 50 feet of property lines of the project site.
(6)
An overlay showing soil types and boundaries based on the Lehigh
or Northampton County Soil Survey, as applicable, latest edition.
Any hydric soils present on the site should be identified as such.
(7)
An overlay showing geologic types, boundaries and any special geologic
features present on the site.
(8)
Proposed changes to land surface and vegetative cover.
(9)
Proposed structures, roads, paved areas and buildings.
(10)
Final contours at intervals of two feet. In areas of steep slopes
(greater than 15%), five-foot contour intervals may be used.
(11)
Stormwater management district boundaries applicable to the
site.
(12)
Clear identification of the location and nature of permanent
stormwater BMPs.
(13)
An adequate access easement around all stormwater BMPs that
would provide municipal ingress to and egress from a public right-of-way.
(14)
A schematic showing all tributaries contributing flow to the
site and all existing man-made features beyond the property boundary
that would be affected by the project.
(15)
The location of all public water supply wells within 400 feet
of the project and all private water supply wells within 100 feet
of the project.
C.
Stormwater management controls and BMPs.
(1)
All stormwater management controls and BMPs shall be shown on a map
and described, including:
(a)
Groundwater recharge methods such as seepage pits, beds or trenches.
When these structures are used, the locations of septic tank infiltration
areas and wells shall be shown.
(b)
Other control devices or methods such as rooftop storage, semipervious
paving materials, grass swales, parking lot ponding, vegetated strips,
detention or retention ponds, storm sewers, etc.
(2)
All calculations, assumptions and criteria used in the design of
the BMPs shall be shown.
(3)
All site testing data used to determine the feasibility of infiltration
on a site.
(4)
All details and specifications for the construction of the stormwater
management controls and BMPs.
D.
The BMP operations and management plan, as required in §§ 203-53 through 203-59, describing how each permanent stormwater BMP will be operated and maintained and the identity of the person(s) responsible for operations and maintenance. A statement must be included, signed by the landowner, acknowledging that the stormwater BMPs are fixtures that cannot be altered or removed without approval by the municipality.
E.
An Environmental Resources Site Design Assessment that describes
the following:
(1)
The extent to which the proposed grading and impervious cover avoid
disturbance of significant environmental resources and preserve existing
site hydrology.
(2)
An assessment of whether alternative grading and impervious cover
site design could lessen the disturbance of significant environmental
resources and/or make better use of the site hydrologic resources.
(3)
A description of how the proposed stormwater management controls
and BMPs serve to mitigate any adverse impacts on environmental resources
on the site. Significant environmental resources considered in the
site design assessment include, but are not limited to, steep slopes,
ponds, lakes, streams, wetlands, hydric soils, floodplains, riparian
vegetation, native vegetation and special geologic features.
A.
(1)
The drainage plan shall be submitted by the developer to the municipal
secretary (or other appropriate person) as part of the preliminary
plan submission for the subdivision or land development.
(2)
Four copies of the drainage plan shall be submitted.
(4)
Drainage plans involving more than 10,000 square feet of additional
impervious cover shall be submitted by the developer (possibly through
the municipality) to the Lehigh Valley Planning Commission as part
of the preliminary plan submission. The Lehigh Valley Planning Commission
will conduct an advisory review of the drainage plan for consistency
with the Hokendauqua Creek and Lehigh River Sub-basins Watershed Stormwater
Management Plan. The LVPC will not review details of the Erosion and
Sedimentation Plan or the BMP operations and maintenance plan.
(a)
Two copies of the drainage plan shall be submitted.
(b)
The LVPC will provide written comments to the developer and
the municipality, within a time frame consistent with established
procedures under the Municipalities Planning Code, as to whether the
drainage plan has been found to be consistent with the stormwater
management plan.
C.
(1)
The drainage plan shall be submitted by the developer to the Lehigh Valley Planning Commission for coordination with the DEP permit application process under Chapter 105 (Dam Safety and Waterway Management), Chapter 106 (Floodplain Management) of DEP's rules and regulations and the NPDES regulations.
(2)
One copy of the drainage plan shall be submitted.
A.
The municipality shall review the drainage plan, including the BMP
operations and maintenance plan, for consistency with the adopted
Hokendauqua Creek and Lehigh River Sub-basins Watershed Stormwater
Management Plan as embodied by this article and with any permits issued
by DEP. The municipality shall also review the drainage plan against
any additional storm drainage provisions contained in the municipal
subdivision and land development or zoning ordinance, as applicable.
B.
The municipality shall notify the applicant in writing whether the
drainage plan, including the BMP operations and maintenance plan,
is approved.
D.
The municipality may require an "as-built" survey of all stormwater
BMPs and an explanation of any discrepancies with the drainage plan.
A modification to a submitted drainage plan for a proposed development site which involves a change in control methods or techniques, or which involves the relocation or redesign of control measures, or which is necessary because soil or other conditions are not as stated on the drainage plan (as determined by the municipality) shall require a resubmission of the modified drainage plan consistent with § 203-46 subject to review per § 203-47 of this article.
A.
The municipality may hear requests for waivers where it is alleged
that the provisions of this article inflict unnecessary hardship upon
the applicant. The waiver request shall be in writing and accompanied
by the requisite fee based upon a fee schedule adopted by the municipality.
A copy of the waiver request shall be provided to each of the following:
municipality, municipal engineer, municipal solicitor and Lehigh Valley
Planning Commission. The request shall fully document the nature of
the alleged hardship.
B.
The municipality may grant a waiver provided that all of the following
findings are made in a given case:
(1)
That there are unique physical circumstances or conditions, including
irregularity of lot size or shape, or exceptional topographical or
other physical conditions peculiar to the particular property, and
that the unnecessary hardship is due to such conditions, and not the
circumstances or conditions generally created by the provisions of
this article in the stormwater management district in which the property
is located;
(2)
That because of such physical circumstances or conditions, there
is no possibility that the property can be developed in strict conformity
with the provisions of this article, including the "no harm" provisions,
and that the authorization of a waiver is therefore necessary to enable
the reasonable use of the property;
(3)
That such unnecessary hardship has not been created by the applicant;
(4)
That the waiver, if authorized, will represent the minimum waiver
that will afford relief and will represent the least modification
possible of the regulation in issue; and
(5)
That financial hardship is not the criteria for granting of a hardship
waiver.
C.
In granting any waiver, the municipality may attach such conditions
and safeguards as it may deem necessary to implement the purposes
of this article. If a hardship waiver is granted, the applicant must
still manage the quantity, velocity, direction and quality of resulting
storm runoff as is necessary to prevent injury to health, safety or
other property.
F.
The municipality shall not waive the water quality provisions of
this article.
A.
DEP or its designees (e.g., County Conservation District) normally
ensure compliance with any permits issued, including those for stormwater
management. In addition to DEP compliance programs, the municipality
or its designee may inspect all phases of the construction, operations,
maintenance and any other implementation of stormwater BMPs.
B.
During any stage of the regulated earth disturbance activities, if
the municipality or its designee determines that any BMPs are not
being implemented in accordance with this article, the municipality
may suspend or revoke any existing permits issued by the municipality
or other approvals issued by the municipality until the deficiencies
are corrected.
The municipality may charge a reasonable fee for review of the
drainage plan, including the BMP operations and maintenance plan,
to defray review costs incurred by the municipality. The applicant
shall pay all such fees.
The fees required by this article shall at a minimum cover:
A.
The review of the drainage plan, including the BMP operations and
maintenance plan, by the municipality.
B.
The site inspection.
C.
The inspection of required controls and improvements during construction.
D.
The final inspection upon completion of the controls and improvements
required in the plan.
E.
Any additional work required to monitor and enforce any permit provisions,
regulated by this article, correct violations, and assure the completion
of stipulated remedial actions.
F.
Administrative and clerical costs.
No regulated earth disturbance activities within the municipality
shall commence until approval by the municipality of the BMP operations
and maintenance plan which describes how the permanent (e.g., postconstruction)
stormwater BMPs will be properly operated and maintained.
A.
The BMP operations and maintenance plan for the project site shall
establish responsibilities for the continuing operation and maintenance
of all permanent stormwater BMPs, as follows:
(1)
If a plan includes structures or lots which are to be separately
owned and in which streets, sewers and other public improvements are
to be dedicated to the municipality, stormwater BMPs may also be dedicated
to and maintained by the municipality;
(2)
If a plan includes operations and maintenance by a single owner or
if sewers and other public improvements are to be privately owned
and maintained, then the operation and maintenance of stormwater BMPs
shall be the responsibility of the owner or private management entity.
B.
The municipality shall make the final determination on the continuing
operations and maintenance responsibilities. The municipality reserves
the right to accept or reject the operations and maintenance responsibility
for any or all of the stormwater BMPs.
It shall be unlawful to alter or remove any permanent stormwater
BMP required by an approved BMP operations and maintenance plan or
to allow the property to remain in a condition which does not conform
to an approved BMP operations and maintenance plan unless an exception
is granted in writing by the municipality.
A.
The property owner shall sign an operations and maintenance agreement
with the municipality covering all stormwater BMPs that are to be
privately owned. The agreement shall be substantially the same as
the agreement in Appendix E of this article.[1]
[1]
Editor's Note: Appendix E is on file in the Borough offices.
B.
Other items may be included in the agreement where determined by
the municipality to be reasonable or necessary to guarantee the satisfactory
operation and maintenance of all permanent stormwater BMPs. The agreement
shall be subject to the review and approval of the municipality.
Stormwater management easements shall be provided by the property owner if necessary for access for inspections and maintenance or for preservation of stormwater conveyance, infiltration, detention areas and other BMPs by persons other than the property owner. The purpose of the easement shall be specified in any agreement under § 203-56.
A.
The owner of any land upon which permanent BMPs will be placed, constructed
or implemented, as described in the BMP operations and maintenance
plan, shall record the following documents in the Office of the Recorder
of Deeds for Lehigh or Northampton County, as applicable, within 90
days of approval of the BMP operations and maintenance plan by the
municipality:
B.
The municipality may suspend or revoke any approvals granted for
the project site upon discovery of the failure of the owner to comply
with this section.
A.
If stormwater BMPs are accepted by the municipality for dedication,
the municipality may require the applicant to pay a specified amount
to the Municipal Stormwater BMP Operations and Maintenance Fund to
help defray costs of operations and maintenance activities. The amount
may be determined as follows:
B.
If a BMP is proposed that also serves as a recreation facility (e.g.,
ball field, lake), the municipality may adjust the amount due accordingly.
A.
No person in the municipality shall allow or cause to allow stormwater discharges into the municipality's separate storm sewer system which are not composed entirely of stormwater except as provided in Subsection B below or as allowed under a state or federal permit.
B.
Discharges that may be allowed based on the municipality finding
that the discharge(s) do not significantly contribute pollution to
surface waters of the commonwealth are listed below.
(1)
Discharges from fire-fighting activities.
(2)
Potable water sources including dechlorinated water line and fire
hydrant flushings.
(3)
Irrigation drainage.
(4)
Routine external building washdown which does not use detergents
or other compounds.
(5)
Air-conditioning condensate.
(6)
Water from individual residential car washing.
(7)
Springs.
(8)
Water from crawl space pumps.
(9)
Uncontaminated water from foundation or footing drains.
(10)
Flows from riparian habitats and wetlands.
(11)
Lawn watering.
(12)
Pavement washwaters where spills or leaks of toxic or hazardous
materials have not occurred (unless all spill material has been removed)
and where detergents are not used.
(13)
Dechlorinated swimming pool discharges.
(14)
Uncontaminated groundwater.
C.
In the event that the municipality determines that any of the discharges identified in Subsection B significantly contribute to pollution of waters of the commonwealth or is so notified by DEP, the municipality will notify the responsible person to cease the discharge.
D.
Upon notice provided by the municipality under Subsection C, the discharger will have a reasonable time, as determined by the municipality, to cease the discharge consistent with the degree of pollution caused by the discharge.
E.
Nothing in this section shall affect a discharger's responsibilities
under state law.
The following connections are prohibited, except as provided in § 203-60B above:
A.
Any drain or conveyance, whether on the surface or subsurface, which
allows any nonstormwater discharge including sewage, process wastewater
and wash water to enter the separate storm sewer system and any connections
to the storm drain system from indoor drains and sinks.
B.
Any drain or conveyance connected from a commercial or industrial
land use to the separate storm sewer system which has not been documented
in plans, maps or equivalent records and approved by the municipality.
A.
Roof drains shall not be connected to streets, sanitary or storm sewers or roadside ditches, except as provided in Subsection B.
B.
When it is more advantageous to connect directly to streets or storm
sewers, connections of roof drains to streets or roadside ditches
may be permitted by the municipality.
C.
Roof drains shall discharge to infiltration areas or vegetative BMPs
to the maximum extent practicable.
A.
No person shall modify, remove, fill, landscape or alter any existing
stormwater BMP without the written approval of the municipality unless
it is part of an approved maintenance program.
B.
No person shall place any structure, fill, landscaping or vegetation
into a stormwater BMP or within a drainage easement, which would limit
or alter the functioning of the BMP, without the written approval
of the municipality.
A.
Upon presentation of proper credentials and with the consent of the
landowner, duly authorized representatives of the municipality may
enter at reasonable times upon any property within the municipality
to inspect the implementation, condition or operation and maintenance
of the stormwater BMPs or to investigate or ascertain the condition
of the subject property in regard to any aspect regulated by this
article.
B.
In the event that the landowner refuses admission to the property,
duly authorized representatives of the municipality may seek an administrative
search warrant issued by a Magisterial District Judge to gain access
to the property.
A.
Whenever the municipality finds that a person has violated a prohibition
or failed to meet a requirement of this article, the municipality
may order compliance by written notice to the responsible person.
Such notice may require, without limitation:
(1)
The name of the owner of record and any other person against whom
the municipality intends to take action.
(2)
The location of the property in violation.
(3)
The performance of monitoring, analyses and reporting.
(4)
The elimination of prohibited connections or discharges.
(5)
Cessation of any violating discharges, practices or operations.
(6)
The abatement or remediation of stormwater pollution or contamination
hazards and the restoration of any affected property.
(7)
Payment of a fine to cover administrative and remediation costs.
(8)
The implementation of stormwater BMPs.
(9)
Operation and maintenance of stormwater BMPs.
B.
Such notification shall set forth the nature of the violation(s)
and establish a time limit for correction of the violation(s). Said
notice may further advise that should the violator fail to take the
required action within the established deadline, the work will be
done by the municipality or designee and the expense thereof, together
with all related lien and enforcement fees, charges and expenses,
shall be charged to the violator.
C.
Failure to comply within the time specified shall also subject such
person to the penalty provisions of this article. All such penalties
shall be deemed cumulative and shall not prevent the municipality
from pursuing any and all other remedies available in law or equity.
A.
Any building, land development or other permit or approval issued
by the municipality may be suspended or revoked by the municipality
for:
(1)
Noncompliance with or failure to implement any provision of the permit.
(2)
A violation of any provision of this article.
(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 or approval shall be reinstated by the municipality
when:
(1)
The municipality or designee has inspected and approved the corrections
to the stormwater BMPs or the elimination of the hazard or nuisance.
(2)
The municipality is satisfied that the violation of the ordinance,
law or rule and regulation has been corrected.
(3)
Payment of all municipal fees, costs and expenses related to or arising
from the violation has been made.
C.
A permit or approval which has been revoked by the municipality cannot
be reinstated. The applicant may apply for a new permit under the
procedures outlined in this article.
A.
Any person, partnership or corporation who or which has violated
the provisions of this article shall, upon being found liable therefor
in a civil enforcement proceeding commenced by the municipality, pay
a judgment of not more than $500 plus all court costs, including reasonable
attorney's fees incurred by the municipality as a result thereof.
No judgment shall commence or be imposed, levied or payable until
the date of the determination of a violation by the Magisterial District
Judge. If the defendant neither pays nor timely appeals the judgment,
the municipality may enforce the judgment pursuant to a separate violation,
unless the Magisterial District Judge, determining that there has
been a violation, further determines that there was a good faith basis
for the person, partnership, or corporation violating this article
to have believed that there was no such violation, in which event
there shall be deemed to have been only one such violation until the
fifth day following the date of the determination of a violation by
the Magisterial District Judge, and thereafter each day that a violation
continues shall constitute a separate violation.
B.
The court of common pleas, upon petition, may grant an order of stay
upon cause shown, tolling the per diem judgment pending a final adjudication
of the violation and judgment.
C.
Nothing contained in this section shall be construed or interpreted
to grant to any person or entity other than the municipality the right
to commence any action for enforcement pursuant to this section.
D.
Magisterial District Judges shall have initial jurisdiction in proceedings
brought under this section.
E.
In addition, the municipality, through its solicitor, may institute
injunctive, mandamus or any other appropriate action or proceeding
at law or in equity for the enforcement of this article. 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.
