A.
Stormwater flows onto adjacent property shall not be created, increased, decreased, relocated, or otherwise altered without written approval of the adjacent property owner(s) by the developer. Such stormwater flows shall be subject to the requirements of this chapter. All such stormwater flows shall be contained within easements created in accordance with this chapter and recorded as directed in § 369-33.
(1)
Nothing in this provision shall apply to runoff discharged into waters
of the commonwealth pursuant to an appropriate state or federal permit
or documentation of exemption.
B.
For all regulated activities, unless specifically exempted in § 369-14:
(1)
Preparation and implementation of an approved SWM site plan is required.
(2)
No regulated activities shall commence until the Township issues
written approval of an SWM site plan, which demonstrates compliance
with the requirements of this chapter.
(4)
The SWM site plan approved by the Township shall be on site throughout
the duration of the regulated activities.
C.
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.[1] 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.
[1]
Editor's Note: See 35 P.S. § 691.1 et seq.
D.
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[2] and any more stringent requirements as determined by the
Township.
[2]
Editor's Note: See 32 P.S. § 680.1 et seq.
E.
The Township may, after consultation with PADEP, 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.[3]
[3]
Editor's Note: See 35 P.S. § 691.1 et seq.
F.
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.
G.
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 developments 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
total impervious area on the parcel is subject to the requirements
of this chapter.
H.
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.
I.
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.
J.
Where watercourses traverse a development site, drainage easements
(encompassing the 100-year elevation 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.
K.
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.
L.
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.
M.
Should any stormwater management facility require a dam safety permit
under 25 Pa. Code Chapter 105, the facility shall be designed in accordance
with Chapter 105 and meet the regulations of Chapter 105 concerning
dam safety.
N.
Any stormwater management facilities regulated by this chapter that
will be located on, or discharged onto state highway rights-of-way
shall be subject to approval by the Pennsylvania Department of Transportation
(PennDOT).
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.
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 Township shall permit it on a case-by-case
basis.
R.
Applicants are encouraged to use low impact development practices
to comply with the requirements of this chapter and the state water
quality requirements.
S.
When stormwater management facilities are proposed within 1,000 feet
of a downstream municipality, the developer shall notify the downstream
municipality and supply a copy of the SWM plan, if requested, for
review and comment.
A.
B.
The applicant must utilize the following BMPs 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's proposed development/additional impervious area
may not adversely impact the following:
D.
Single-family residential activities are exempt from these requirements,
provided the construction:
E.
An applicant proposing regulated activities, after demonstrating compliance with § 369-14A, 369-14B, and 369-14C, may be exempted from various requirements of this chapter according to the following table:
|
New Impervious Area1, 2
(square footage)
|
Applicant Must Provide
|
|---|---|
|
0 to 2,500
|
No submission
|
|
2,500 to 5,000
|
Documentation of impervious surfaces (small project SWM application)3
|
|
Greater than 5,000
|
Rate controls, volume controls and SWM site plan
|
|
NOTES:
| |
|
1
|
New impervious area since the date of adoption of this chapter
|
|
2
|
Gravel in existing condition shall be considered pervious and
gravel in proposed condition shall be considered impervious
|
|
3
|
The first page of the small project stormwater management application
included in Appendix E[2] may be used to document new impervious surfaces
|
[2]
Editor's Note: Appendix E is included as an attachment to this chapter.
F.
An applicant proposing regulated activities, after demonstrating
compliance with §§ 369-14A, 369-14B, and 369-14C,
may be exempted from various requirements of this chapter if documentation
can be provided that a downstream man-made water body (i.e., reservoir,
lake, or man-made wetlands) has been designed or modified to address
the potential stormwater flooding impacts of the proposed development.
G.
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 Township may accept alternative stormwater management
controls under this section, provided that:
(1)
The Township, in consultation with the PADEP, determines that meeting the volume control requirements (see § 369-16) is not possible or places an undue hardship on the applicant.
(2)
The alternative controls are documented to be acceptable to PADEP
for NPDES requirements pertaining to post-construction stormwater
management requirements.
H.
Agricultural activity is exempt from the rate control and SWM site
plan preparation requirements of this chapter, provided the activities
are performed according to the requirements of 25 Pa. Code Chapter
102.
I.
Forest management and timber operations are exempt from the rate
and volume control requirement 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.
(1)
All temporary and permanent haul roads that are not to receive an
asphalt wearing course shall be designed and constructed consistent
with recommendations of the Center for Dirt and Gravel Road Studies
and the PA State Conservation Commission's Dirt and Gravel Road
Maintenance Program.
J.
For a parcel or tract of land held under single ownership, only one
application for a small development, as defined above, shall be permitted
before requiring a stormwater management plan for the entire parcel.
A.
The provisions of this chapter are the minimum standards for the
protection of the public welfare.
B.
(1)
Waivers shall not be issued from implementing such measures as necessary
to:
(2)
The Township will then consider waivers in accordance with § 369-13E, which states that the Township may, after consultation with PADEP, 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.[1]
[1]
Editor's Note: See 35 P.S. § 691.1 et seq.
C.
If an applicant demonstrates to the satisfaction of the governing body of the Township that any mandatory provision of this chapter is unreasonable or causes unique or undue unreasonableness or hardship as it applies to the proposed project, or that an alternate design may result in a superior result within the context of §§ 369-2 and 369-3 of this chapter, the governing body of the municipality, upon obtaining the comments and recommendations of the Township Engineer, may grant a waiver or relief so that substantial justice may be done and the public interest is secured, provided that such waiver will not have the effect of nullifying the intent and purpose of this chapter.
D.
The applicant shall submit all requests for waivers in writing and
shall include such requests as a part of the plan review and approval
process. The applicant shall state in full the facts of unreasonableness
or hardship on which the request is based, the provision or provisions
of this chapter that are involved, and the minimum waiver or relief
that is necessary. The applicant shall state how the requested waiver
and how the applicant's proposal shall result in an equal or
better means of complying with the intent or purpose and general principles
of this chapter.
E.
The Township shall keep a written record of all actions on waiver
requests.
F.
The Township may charge a fee for each waiver request, which shall
be used to offset the administrative costs of reviewing the waiver
request. The applicant shall also agree to reimburse the Township
for reasonable and necessary fees that may be incurred by the Township
Engineer in any review of a waiver request.
G.
In granting waivers, the Township may impose reasonable conditions
that will, in its judgment, secure substantially the objectives of
the standards or requirements that are to be modified.
H.
The Township may grant applications for waivers when the following
findings are made, as relevant:
(1)
That the waiver shall result in an equal or better means of complying
with the intent of this chapter.
(a)
The waiver is the minimum necessary to provide relief.
(b)
The applicant is not requesting a waiver based on cost considerations.
(c)
Existing down gradient stormwater problems will not be exacerbated.
(d)
Runoff is not being diverted to a different drainage area.
(e)
Increased flooding or ponding on off-site properties or roadways
will not occur.
(f)
Potential icing conditions will not occur.
(g)
Increase of peak flow or volume from the site will not occur.
(h)
Erosive conditions due to increased peak flows or volume will
not occur.
(i)
Adverse impact to water quality will not result.
(j)
Increased 100-year floodplain levels will not result.
(k)
Infiltration of runoff throughout the proposed site has been
provided where practicable and predevelopment groundwater recharge
protected.
(l)
Peak flow attenuation of runoff has been provided.
(m)
Long-term operation and maintenance activities are established.
(n)
The receiving streams and/or water bodies will not be adversely
impacted in flood-carrying capacity, aquatic habitat, channel stability
and erosion and sedimentation.
A.
The low impact development practices provided in the BMP Manual and
in Appendix B[1] of this chapter shall be utilized for all regulated activities
to the maximum extent practicable.
[1]
Editor's Note: Appendix B is included as an attachment to this chapter.
B.
The small project stormwater management application included in Appendix
E[2] may be used for projects under 5,000 square feet of new
impervious surface and single-family home construction. The small
project SWM application allows documentation of new impervious surface,
credits through disconnection of impervious surfaces and tree planting,
and sizing of volume control BMPs that may be required.
[2]
Editor's Note: Appendix E is included as an attachment to this chapter.
C.
Stormwater runoff volume controls shall be implemented using the
Design Storm Method or the Simplified Method as defined below. For
regulated activity areas equal or less than one acre that do not require
hydrologic routing to design the stormwater facilities, 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 size 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 pre-development hydrologic calculations.
[2]
20% of existing impervious area, when present within the proposed
project site, 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 or for projects that require detailed design of stormwater
storage facilities. 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 0.5 inch of the permanently
removed runoff should be infiltrated.
(d)
Actual field infiltration tests at the location of the proposed
elevation of the stormwater BMPs are required. Infiltration test shall
be conducted in accordance with the BMP Manual. Notification of the
Township shall be provided to allow witnessing of the testing.
(3)
In cases where it is not possible or desirable to use infiltration-based best management practices to partially fulfill the requirements in either § 369-16C(1) or (2), the following procedure shall be used:
(a)
At a minimum, the following documentation shall be provided
to justify the decision to not use infiltration BMPs:
[1]
Description of and justification for field infiltration/permeability
testing with respect to the type of test and test locations.
[2]
An interpretive narrative describing existing site soils and
their structure as these relate to the interaction between soils and
water occurring on the site. In addition to providing soil and soil
profile descriptions, this narrative shall identify depth to seasonal
high-water tables and depth to bedrock, and provide a description
of all subsurface elements (fragipans and other restrictive layers,
geology, etc.) that influence the direction and rate of subsurface
water movement.
[3]
A qualitative assessment of the site's contribution to
annual aquifer recharge shall be made, along with identification of
any restrictions or limitations associated with the use of engineered
infiltration facilities.
[4]
The provided documentation must be signed and sealed by a professional
engineer or geologist.
(b)
The following water quality pollutant load reductions will be
required for all disturbed areas within the proposed development:
|
Pollutant Load
|
Units
|
Required Reduction
Percent
|
|---|---|---|
|
Total suspended solids (TSS)
|
Pounds
|
85%
|
|
Total phosphorous (TP)
|
Pounds
|
85%
|
|
Total nitrate (NO3)
|
Pounds
|
50%
|
(c)
The performance criteria for water quality best management practices
shall be determined from the Pennsylvania Stormwater Best Management
Practices Manual, most current version.
D.
The applicable Worksheets from the BMP Manual must be used in calculations
to establish volume control.
A.
Lands contained within Washington County that have not had release
rates established under an approved Act 167 stormwater management
plan:
(1)
Post-development discharge rates shall not exceed 90% of the predevelopment
discharge rates for the one-, two-, ten-, twenty-five-, fifty-, and
100-year storms.
(2)
In order to achieve this, it is recommended that methods be considered
that will direct runoff from impervious areas to pervious areas or
infiltration trenches that will retain, detain, or control the rate
and volume of runoff discharge by some other means suitable to the
Township.
(3)
The post-developed, twenty-five-year-storm event peak discharge shall
not exceed the capacity of downstream stormwater facilities.
B.
Lands contained within Washington County that have had release rates
established under an approved Act 167 stormwater management plan:
(1)
Chartiers Creek watershed. The post-development peak discharge rates
shall be in accordance with the approved release rate map for the
individual watershed. Release rates include 50%, 70% and 100% for
the ten-, twenty-five-, fifty- and 100-year storms.
A.
In conjunction with meeting the requirements of this chapter, the applicant shall refer to and meet all conditions and requirements set forth in Chapter 365, Storm Sewers, of the Code of the Township of Robinson.
B.
In conjunction with meeting the requirements of this chapter, the
applicant shall refer to and meet all conditions and requirements
set forth in the Robinson Township's Total Maximum Daily Load
(TMDL) Plan, as adopted and revised.
