A.
For all regulated activities, unless specifically exempted in § 360-11 of this chapter:
(1)
Preparation and implementation of an approved SWM site plan is required.
(2)
No regulated activities shall commence until the Borough issues written
approval of a SWM site plan which demonstrates compliance with the
requirements of this chapter.
(4)
The SWM site plan approved by the Borough shall be on-site throughout
the duration of the regulated activities.
B.
For all regulated earth disturbance activities, erosion and sediment
control BMPs shall be designed, implemented, operated and maintained
during the regulated earth disturbance activities (e.g., during construction)
to meet the purposes and requirements of this chapter and to meet
all requirements under Title 25 of the Pennsylvania Code (including,
but not limited to, Chapter 102, Erosion and Sediment Control) and
the Clean Streams Law. Various BMPs and their design standards are
listed in the Erosion and Sediment Pollution Control Program Manual
(E&S Manual), No. 363-2134-008 (April 15, 2000), as amended and
updated.
C.
For all regulated activities, stormwater BMPs shall be designed,
installed, implemented, operated and maintained to meet the purposes
and requirements of this chapter and to meet all requirements under
Title 25 of the Pennsylvania Code and the Clean Streams Law, conform
to the state water quality requirements, meet all requirements under
the Storm Water Management Act and any more stringent requirements
as determined by the Borough.
D.
The Borough may, after consultation with PADEP and/or DCCD, approve
measures for meeting the state water quality requirements other than
those in this chapter, provided that they meet the minimum requirements
of, and do not conflict with, state law, including, but not limited
to, the Clean Streams Law.
E.
All regulated activities shall include, to the maximum extent practicable,
measures to:
(1)
Protect health, safety and property.
(2)
Meet the water quality goals of this chapter by implementing measures
to:
(a)
Minimize disturbance to floodplains, wetlands, natural slopes,
existing native vegetation and woodlands.
(b)
Create, maintain or extend riparian buffers and protect existing
forested buffers.
(c)
Provide trees and woodlands adjacent to impervious areas whenever
feasible.
(d)
Minimize the creation of impervious surfaces and the degradation
of waters of the commonwealth and promote groundwater recharge.
(e)
Protect natural systems and processes (drainageways, vegetation,
soils and sensitive areas) and maintain, as much as possible, the
natural hydrologic regime.
(f)
Incorporate natural site elements (wetlands, stream corridors,
mature forests) as design elements.
(g)
Avoid erosive flow conditions in natural flow pathways.
(h)
Minimize soil disturbance and soil compaction.
(i)
Minimize thermal impacts to waters of the commonwealth.
(j)
Disconnect impervious surfaces by directing runoff to pervious
areas wherever possible, and decentralize and manage stormwater at
its source.
(3)
Applicants are encouraged to incorporate the techniques for low-impact
development practices described in the Pennsylvania Stormwater Best
Management Practices Manual (BMP Manual) to reduce the costs of complying
with the requirements of this chapter and the state water quality
requirements.
F.
Impervious areas:
(1)
The measurement of impervious areas shall include all of the impervious
areas in the total proposed development, even if development is to
take place in stages.
(2)
For development taking place in stages, the entire development plan
must be used in determining conformance with this chapter.
(3)
For projects that add impervious area to a developed parcel, the
new impervious area is subject to the requirements of this chapter;
and any existing impervious area that is within the new proposed limit
of disturbance is also subject to the requirements of this chapter.
G.
If diffused flow is proposed to be concentrated and discharged onto
adjacent property, the applicant must document that adequate downstream
conveyance facilities exist to safely transport the concentrated discharge,
or otherwise prove that no erosion, sedimentation, flooding, or other
harm will result from the concentrated discharge.
(1)
Applicant must provide an executed easement for newly concentrated
flow across adjacent properties.
H.
Stormwater drainage systems shall be provided in order to permit
unimpeded flow along natural watercourses, except as modified by stormwater
management facilities or open channels consistent with this chapter.
I.
Where watercourses traverse a development site, drainage easements
(with a minimum width of 20 feet) shall be provided, conforming to
the line of such watercourses. The terms of the easement shall prohibit
excavation, the placing of fill or structures, and any alterations
that may adversely affect the flow of stormwater within any portion
of the easement. Also, maintenance, including mowing of vegetation
within the easement, may be required, except as approved by the appropriate
governing authority.
J.
When it can be shown that, due to topographic conditions, natural
drainageways on the site cannot adequately provide for drainage, open
channels may be constructed conforming substantially to the line and
grade of such natural drainageways. Work within natural drainageways
shall be subject to approval by PADEP under regulations at 25 Pa.
Code Chapter 105 through the joint permit application process or,
where deemed appropriate by PADEP, through the general permit process.
K.
Any stormwater management facilities or any facilities that constitute
water obstructions (e.g., culverts, bridges, outfalls or stream enclosures,
etc.) that are regulated by this chapter, that will be located in
or adjacent to waters of the commonwealth (including wetlands), shall
be subject to approval by PADEP under regulations at 25 Pa. Code Chapter
105 through the joint permit application process or, where deemed
appropriate by PADEP, the general permit process. When there is a
question whether wetlands may be involved, it is the responsibility
of the applicant or his agent to show that the land in question cannot
be classified as wetlands; otherwise, approval to work in the area
must be obtained from PADEP.
L.
Should any stormwater management facility require a dam safety permit
under PADEP Chapter 105, the facility shall be designed in accordance
with Chapter 105 and meet the regulations of Chapter 105 concerning
dam safety, which may be required to pass storms larger than the one-hundred-year
event.
M.
Any stormwater management facilities regulated by this chapter that
will be located on or discharged onto state highway rights-of-ways
shall be subject to approval by the Pennsylvania Department of Transportation
(PennDOT).
N.
When stormwater management facilities are proposed within 1,000 feet
of a downstream municipality, the stormwater analysis shall be submitted
to the downstream municipality's engineer for review and comment.
O.
Minimization of impervious surfaces and infiltration of runoff through
seepage beds, infiltration trenches, etc., are encouraged, where soil
conditions and geology permit, to reduce the size or eliminate the
need for detention facilities.
P.
Infiltration BMPs should be dispersed throughout the site, made as
shallow as practicable, and located to maximize use of natural on-site
infiltration features while still meeting the other requirements of
this chapter.
Q.
The design of facilities over karst features shall include an evaluation
and implementation of measures to minimize adverse effects.
R.
Roof drains shall not be connected to streets, sanitary or storm
sewers, or roadside ditches in order to promote overland flow and
infiltration/percolation of stormwater where it is advantageous to
do so. When it is more advantageous to connect directly to streets
or storm sewers, then the Borough shall permit it on a case-by-case
basis.
B.
The applicant must demonstrate that the following BMPs are being
utilized to the maximum extent practicable to receive consideration
for the exemptions:
(1)
Design around and limit disturbance of floodplains, wetlands, natural
slopes over 15%, existing native vegetation, and other sensitive and
special value features.
(2)
Maintain riparian and forested buffers.
(3)
Limit grading and maintain nonerosive flow conditions in natural
flow paths.
(4)
Maintain existing tree canopies near impervious areas.
(5)
Minimize soil disturbance and reclaim disturbed areas with topsoil
and vegetation.
(6)
Direct runoff to pervious areas.
C.
The applicant must demonstrate that the proposed development/additional
impervious area will not adversely impact the following:
D.
An applicant proposing regulated activities, after demonstrating compliance with Subsections A, B and C of this section, may be exempted from various requirements of this chapter according to the following table:
|
New Impervious Area*
(Since Date of Adoption of Chapter)
(square feet)
|
Applicant Must Submit to Borough
| |
|---|---|---|
|
0 to 1,000
|
—
| |
|
1,000 to 5,000
|
Volume controls and SWM site plan and report
| |
|
Greater than 5,000
|
Rate controls, volume controls, SWM site plan and report and
record drawings
|
|
NOTES:
| ||
|---|---|---|
|
*
|
Gravel in the existing condition shall be considered pervious,
and proposed gravel shall be considered impervious.
| |
E.
The purpose of this section is to ensure consistency of stormwater
management planning between local ordinances and NPDES permitting
(when required) and to ensure that the applicant has a single and
clear set of stormwater management standards to which the applicant
is subject. The Borough may accept alternative stormwater management
controls, provided that:
(1)
The applicant, in consultation with the Borough, PADEP and/or DCCD,
states that meeting the requirements of the volume controls or rate
controls of this chapter is not possible or creates an undue hardship.
(2)
The alternative stormwater management controls proposed by the applicant
are documented to be acceptable to the Borough, PADEP and/or DCCD
for NPDES requirements pertaining to post-construction stormwater
management requirements.
F.
Forest management and timber operations are exempt from rate and
volume control requirements and SWM site plan preparation requirement
of this chapter, provided the activities are performed according to
the requirements of 25 Pa. Code Chapter 102. It should be noted that
temporary roadways are not exempt.
G.
Agricultural activities are exempt from the requirements of this
chapter, provided the activities are performed according to the requirements
of 25 Pa. Code Chapter 102.
H.
Linear roadway improvement projects that create additional impervious
area are not exempt from the requirements of this chapter. However,
alternative stormwater management strategies may be applied at the
joint approval of the Borough and the DCCD (if an NPDES permit is
required) when site limitations (such as limited right-of-way) and
constraints (as shown and provided by the applicant), preclude the
ability of the applicant to meet the enforcement of the stormwater
management standards in this chapter. All strategies must be consistent
with PADEP's regulations, including NPDES requirements.
I.
The Borough may, after an applicant has demonstrated compliance with Subsections A, B and C of this section, grant a modification of the requirements of one or more provisions of this chapter if the literal enforcement will exact undue hardship because of peculiar conditions pertaining to the land in question, provided that such modification will not be contrary to the public interest and that the purpose and intent of the chapter is observed. All requests for a modification shall be in writing and shall state in full the grounds and facts of unreasonableness or hardship on which the request is based, the provision or provisions of the chapter involved, and the minimum modification necessary.
A.
Applicants are encouraged to utilize the low-impact development practices
provided in the BMP Manual and in Appendix B[1] of this chapter for all regulated activities to the maximum
extent practicable.
[1]
Editor's Note: Appendix B is attached to this chapter.
B.
Stormwater runoff volume controls shall be implemented using the
Design Storm Method or the Simplified Method. For regulated activities
equal to or less than one acre, this chapter establishes no preference
for either method; therefore, the applicant may select either method
on the basis of economic considerations, the intrinsic limitations
on applicability of the analytical procedures associated with each
methodology, and other factors.
(1)
The Design Storm Method (CG-1 in the BMP Manual) is applicable to
any sized regulated activity. This method requires detailed modeling
based on site conditions.
(a)
Do not increase the post-development total runoff volume when
compared to the predevelopment total runoff volume for the two-year/twenty-four-hour
storm event.
(b)
For hydrologic modeling purposes:
[1]
Existing nonforested pervious areas must be considered "meadow"
(good condition) for predevelopment hydrologic calculations.
[2]
Twenty percent of existing impervious area, when present on
the proposed project site and contained within the new proposed limit
of disturbance, shall be considered "meadow" (good condition) for
predevelopment hydrologic calculations for redevelopment.
(2)
The Simplified Method (CG-2 in the BMP Manual) is independent of
site conditions and should be used if the Design Storm Method is not
followed. This method is not applicable to regulated activities greater
than one acre. For new impervious surfaces:
(a)
Stormwater facilities shall capture at least the first two inches
of runoff from all new impervious surfaces.
(b)
At least the first one inch of runoff from new impervious surfaces
shall be permanently removed from the runoff flow, i.e., it shall
not be released into surface waters of the commonwealth. Removal options
include reuse, evaporation, transpiration and infiltration.
(c)
Wherever possible, infiltration facilities should be designed
to accommodate infiltration of the entire permanently removed runoff;
however, in all cases at least the first 1/2 inch of the permanently
removed runoff should be infiltrated.
C.
All applicable worksheets from Chapter 8 of the BMP Manual must be
used when establishing volume controls.
D.
Actual field infiltration tests at the location of the proposed elevation
of the stormwater BMPs are required when 5,000 square feet or greater
of new impervious surface is added. Infiltration test shall be conducted
in accordance with the BMP Manual. The Borough shall be notified 24
hours prior to infiltration tests being conducted as to provide an
opportunity for the Borough to witness the tests.
A.
Lands contained within the Borough that have not had release rates
established under an approved Act 167 stormwater management plan:
(1)
Post-development discharge rates shall not exceed the predevelopment
discharge rates for the one-year, two-year, ten-year, twenty-five-year,
fifty-year and one-hundred-year storms.
B.
Lands contained within the Borough that have had release rates established
under an approved Act 167 stormwater management plan [Spring Creek
(West) Watershed]:
(1)
Post-development discharge rates shall not exceed the predevelopment
discharge rates for the one-year, fifty-year and one-hundred-year
storms.
(2)
For the two-year, ten-year and twenty-five-year storms, the post-development
peak discharge rates shall be in accordance with the approved release
rate map for the individual watershed [see Plate 5, Spring Creek (West)
Subwatershed Release Rates].
