[Ord. 1-2012, 9/19/2012, § 101]
This chapter shall be known as the "Thornbury Township Stormwater
Management Ordinance."
[Ord. 1-2012, 9/19/2012, § 102]
1.
The Board of Supervisors of the Township finds that:
A.
Inadequate management of accelerated stormwater runoff resulting
from development throughout a watershed increases flood flows and
velocities, contributes to erosion and sedimentation, overtaxes the
carrying capacity of existing streams and storm sewers, greatly increases
the cost of public facilities to convey and manage stormwater, undermines
floodplain management and flood reduction efforts in upstream and
downstream communities, reduces infiltration, and threatens public
health and safety.
B.
Inadequate planning and management of stormwater runoff resulting
from land development throughout a watershed can also harm surface
water resources by changing the natural hydrologic patterns, accelerating
stream flows (which increase scour and erosion of stream beds and
stream banks, thereby elevating sedimentation), destroying aquatic
habitat, and elevating aquatic pollutant concentrations and loadings
such as sediments, nutrients, heavy metals, and pathogens. Groundwater
resources are also impacted through loss of recharge.
C.
A comprehensive program of stormwater management, including minimization
of impacts of development, redevelopment, and activities causing accelerated
erosion and loss of natural infiltration, is fundamental to the public
health, safety, welfare, and the protection of the people of the Township
and all of the people of the commonwealth, their resources, and the
environment.
D.
Stormwater can be an important water resource by providing infiltration
for water supplies and baseflow of streams, which also protects and
maintains surface water quality.
E.
Impacts from stormwater runoff can be minimized by using project
designs that maintain the natural hydrologic regime and sustain high
water quality, infiltration, stream baseflow, and aquatic ecosystems.
The most cost-effective and environmentally advantageous way to manage
stormwater runoff is through nonstructural project design that minimizes
impervious surfaces and sprawl, avoids sensitive areas (i.e., stream
buffers, floodplains, steep slopes), and considers topography and
soils to maintain the natural hydrologic regime.
F.
Public education on the control of pollution from stormwater is an
essential component in successfully addressing stormwater.
G.
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).
H.
Non-stormwater discharges to Township separate storm sewer systems
can contribute to pollution of waters of the commonwealth by the Township.
I.
The use
of green infrastructure and low-impact development (LID) are intended
to address the root cause of water quality impairment by using systems
and practices which use or mimic natural processes for: 1) infiltration
and recharge, 2) evapotranspiration, and/or 3) harvest and use precipitation
near where it falls to earth. Green infrastructure practices, LID,
and CD contribute to the restoration or maintenance of predevelopment
hydrology.
[Added by Ord. No. 3-2022, 9/21/2022]
[Ord. 1-2012, 9/19/2012, § 103; as amended by Ord. No. 3-2022, 9/21/2022]
1.
The purpose of this chapter is to promote the public health, safety,
and general welfare, within property, and water quality by implementing
drainage and stormwater management practices, criteria, and provisions
included herein for land development, construction, and earth disturbance
activities, to achieve the following throughout the Township.
A.
Promote alternative project designs and layouts that minimize the
impacts on surface and groundwater.
B.
Promote nonstructural best management practices (BMPs).
C.
Minimize increases in runoff stormwater volume.
D.
Minimize impervious surfaces.
E.
Manage accelerated stormwater runoff and erosion and sedimentation
problems and stormwater runoff impacts at their source by regulating
activities that cause these problems.
F.
Provide review procedures and performance standards for stormwater
planning and management.
G.
Utilize and preserve existing natural drainage systems as much as
possible.
H.
Manage stormwater impacts close to the runoff source, requiring a
minimum of structures and relying on natural processes.
I.
Focus on infiltration of stormwater to maintain base flow, to prevent
degradation of surface and groundwater quality, and to otherwise protect
water resources.
J.
Protect base flows and quality of streams and watercourses, where
possible.
K.
Meet legal water quality requirements under state law, including
regulations at 25 Pennsylvania Code Chapter 93, to protect, maintain,
reclaim, and restore the existing and designated uses of the waters
of the commonwealth.
L.
Address the quality and quantity of stormwater discharges from the
development site.
M.
Provide standards to meet certain NPDES MS4 permit requirements.
N.
Implement an illicit discharge detection and elimination program
that addresses nonstormwater discharges into the Township's separate
storm sewer system (MS4).
O.
Preserve the flood-carrying capacity of streams.
P.
Prevent accelerated scour, erosion and sedimentation of stream channels.
Q.
Provide performance standards and design criteria based on watershed-wide
stormwater management planning.
R.
Provide proper operation and maintenance of all permanent stormwater
management facilities and BMPs that are implemented within the Township.
S.
Implement
the requirements of total maximum daily loads (TMDLs) where applicable
to waters within or impacted by the Township.
[Ord. 1-2012, 9/19/2012, § 104]
1.
The Township is empowered or required to regulate land use activities
that affect runoff and surface and groundwater quality and quantity
by the authority of:
A.
Act of October 4, 1978, P.L. 864 (Act 167), 32 P.S. § 680.1
et seq., as amended, the "Storm Water Management Act" (hereinafter
referred to as "the Act").
B.
Second Class Township Code, 53 P.S. §§ 66501 et seq.,
66601 et seq.
C.
Act of July 31, 1968, P.L. 805, No. 247, Pennsylvania Municipalities
Planning Code, Act 247, 53 P.S. § 10101 et seq., as amended.
[Ord. 1-2012, 9/19/2012, § 105]
1.
All regulated activities and all activities that may affect stormwater
runoff, including, but not limited to, land development, redevelopment,
and earth disturbance activity located within the Township, are subject
to regulation by this chapter.
2.
This chapter contains the stormwater management performance standards
and design criteria that are necessary from a watershed-wide perspective.
Local stormwater management design criteria (e.g., inlet spacing,
inlet type, collection system design and details, outlet structure
design, etc.) shall continue to be regulated by the applicable Township
ordinances and applicable state regulations.
[Ord. 1-2012, 9/19/2012, § 106]
1.
An exemption shall not relieve the applicant from implementing the
requirements of this chapter or from implementing such measures as
are necessary to protect public health, safety, and property. An exemption
shall not relieve the applicant from complying with the special requirements
for watersheds draining to identified high quality (HQ) or exceptional
value (EV) waters or any other current or future state or Township
water quality protection requirements. If a drainage problem is documented
or known to exist downstream of, or is expected from the proposed
activity, then the Township may withdraw exemptions listed in Table
19-106-1 and require the applicant to comply with all requirements
of this chapter. Even though the applicant is exempt, he is not relieved
from complying with other Township ordinances or regulations.
2.
General Exemptions.
A.
Table 19-106-1 summarizes the exemptions from certain provisions
of this chapter. Exemptions are for the items noted in Table 19-106-1
only, and shall not relieve the applicant from other applicable sections
of this chapter.
B.
Any regulated activity that is exempt from some provisions of the
chapter is exempt only from those provisions. If development is to
take place in phases, the developer is responsible for implementing
the requirements of the chapter as the impervious cover/earth disturbance
threshold is met. The date of this chapter adoption shall be the starting
point from which to consider tracts as "parent tracts" in which future
subdivisions and respective impervious area and earth disturbance
computations shall be cumulatively considered. Exemption shall not
relieve the applicant from implementing such measures as are necessary
to protect health, safety, and property. For example:
(1)
If a property owner proposes a 150-square-foot shed after adoption
of this chapter, that property owner would be exempted from water
quality and quantity requirements of this chapter as noted in Table
19-106-1 of the Code. If, at a later date, the property owner proposes
to construct a 499-square-foot room addition, the applicant would
be required to comply with the requirements for the Simplified Method
for the full 649 square feet of impervious cover created since adoption
of this chapter. If an additional 700-square-foot swimming pool/patio
is proposed later, the property owner would be required to implement
the full stormwater quantity and quality control submission requirements
of this chapter for the total 1,349 square feet of additional impervious
surface added to the original property since adoption of this chapter.
[Amended by Ord. No. 3-2022, 9/21/2022]
|
Table 19-106-1
Chapter Exemptions
| |||||||
|---|---|---|---|---|---|---|---|
|
Regulated Impervious Surface
|
Earth Disturbance
| ||||||
|
Chapter Article or section
|
Type of Project
|
0-499 square feet
|
500-2,000 square feet
|
2,000+ square feet
|
0-4,999 square feet disturb-ance
|
5,000 square feet - < 1 acre
|
> 1 acre
|
|
Article 4 SWM Site Plan Requirements
|
Development Redevelopment
|
Exempt
|
Not Exempt Simplified Approach
|
Not Exempt
|
Exempt
|
Modified1
|
Not Exempt
|
|
§ 19-304 Nonstructural Project Design
|
Development Redevelopment
|
Exempt
|
Not Exempt Simplified Approach
|
Not Exempt
|
Exempt
|
Not Exempt
|
Not Exempt
|
|
§ 19-305 Infiltration Volume Requirements
|
Development Redevelopment
|
Exempt
|
Not Exempt Simplified Approach
|
Not Exempt
|
Exempt
|
Exempt
|
Not Exempt
|
|
§ 19-306 Water Quality Requirements
|
Development Redevelopment
|
Exempt
|
Not Exempt Simplified Approach
|
Not Exempt
|
Modified2
|
Modified2
|
Not Exempt
|
|
§ 19-307 Stream Bank Erosion Requirements
|
Development Redevelopment
|
Exempt
|
Not Exempt Simplified Approach
|
Not Exempt
|
Exempt
|
Exempt
|
Not Exempt
|
|
§ 19-308 Stormwater Peak Rate Control and Management Districts
|
Development Redevelopment
|
Exempt
|
Exempt
|
Not Exempt
|
Exempt
|
Not Exempt
|
Not Exempt
|
|
Erosion and Sediment Pollution Control Requirements
|
Must comply with Title 25, Chapter 102, of the PA Code
and other applicable state and municipal codes, including the Clean
Streams Law
|
Not Exempt
| |||||
|
Legend:
| |
|
•
|
"Regulated Impervious Surface" in this Table 19-106-1
includes new, additional, or replacement impervious surface/cover
as part of development or redevelopment.
|
|
•
|
Exempt-Exempt from required section provision only.
SWM site plan submission may still be required if other section provisions
are applicable.
|
|
•
|
Modified1 - Modified SWM site plan need only consist of items in §§ 19-402, Subsection 2A(2) and (4); 19-402, Subsection 2B(7), (8), (11), and (22); and 19-402, Subsection 4A and C, and related supportive material needed to determine compliance with §§ 19-304 and 19-308. Modified SWM site plan is required that includes all elements of § 19-304, as applicable.
|
|
•
|
Modified2 - Modified SWM site plan need only consist of items and related material needed to determine compliance with § 19-311.
|
|
•
|
Simplified Approach-Must comply with provisions of
Appendix 19-B of this chapter.
|
|
•
| |
3.
Exemptions for Specific Activities.
[Amended by Ord. No. 3-2022, 9/21/2022]
A.
Use of land for gardening or home consumption.
B.
Agriculture when operated in accordance with a conservation plan,
nutrient management plan, or erosion and sedimentation control plan
approved by the County Conservation District, including activities
such as growing crops, rotating crops, tilling soil, and grazing animals.
For agriculture with an approved conservation plan, installation of
new or expansion of existing farmsteads, animal housing, waste storage,
and production areas having impervious surfaces that result in a net
increase in impervious surface of between 500-999 square feet shall
apply the Simplified Approach, and net increases in impervious surface
of greater than or equal to 1,000 square feet shall be subject to
the provisions of this chapter.
C.
High
tunnel if:
(1)
The high tunnel or its flooring does not result in an impervious
surface exceeding 25% of all structures located on the landowner's
total contiguous land area; and
(2)
The high tunnel meets one of the following:
(a)
The high tunnel is located at least 100 feet from any perennial stream
or watercourse, public road, or neighboring property line.
(b)
The high tunnel is located at least 35 feet from any perennial stream
or watercourse, public road or neighboring property line and located
on land with a slope not greater than 7%.
(c)
The high tunnel is supported with a buffer or diversion system that
does not directly drain into a stream or other watercourse by managing
stormwater runoff in a manner consistent with the requirements of
Pennsylvania Act 167.
D.
Forest management operations which are following the Department’s management practices contained in its publication "Soil Erosion and Sedimentation Control Guidelines for Forestry" are operating under an approved erosion and sedimentation plan, and must comply with the stream buffer requirements in § 19-311.
E.
Forest management operations which are following the Department of Environmental Protection's (PADEP) management practices contained in its publication "Soil Erosion and Sedimentation Control Guidelines for Forestry," are operating under an approved erosion and sedimentation plan, and must comply with the stream buffer requirements in § 19-306, Subsection 5.
F.
Repaving without reconstruction.
G.
Emergency Exemption. Emergency maintenance work performed for the
protection of public health, safety, and welfare. A written description
of the scope and extent of any emergency work performed shall be submitted
to the Township within two calendar days of the commencement of the
activity. If the Township finds that the work is not an emergency,
then the work shall cease immediately, until a stormwater site plan
in accordance with this chapter is submitted and approved by the Township.
H.
Maintenance Exemption. Any maintenance to an existing stormwater
management system made in accordance with plans and specifications
approved by the Township.
[Ord. 1-2012, 9/19/2012, § 109]
1.
Approvals issued pursuant to this chapter 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.
2.
To the extent that this chapter imposes more rigorous or stringent
requirements for stormwater management, the specific requirements
contained in this chapter shall be followed.
3.
Nothing in this chapter shall be construed to affect any of the Township's
requirements regarding stormwater matters that do not conflict with
the provisions of this chapter, such as local stormwater management
design criteria (e.g., inlet spacing, inlet type, collection system
design and details, outlet structure design, etc.). Conflicting provisions
in other Township ordinances or regulations shall be construed to
retain. The requirements of this chapter shall supersede any conflicting
requirements in other Township ordinance or regulations.
[Added by Ord. No. 3-2022, 9/21/2022]
Any permit or authorization issued or approved based on false,
misleading, or erroneous information provided by an applicant is void
without the necessity of any proceedings for revocation. Any work
undertaken or use established pursuant to such permit or other authorization
is unlawful. No action may be taken by a board or employee of the
Township purporting to validate such a violation.
[Added by Ord. No. 3-2022, 9/21/2022]
2.
Waivers
or modifications of the requirements of this chapter may be approved
by the Township if enforcement will exact undue hardship because of
peculiar conditions pertaining to the land in question, provided that
the modifications will not be contrary to the public interest and
that the purpose of this chapter is preserved. Cost or financial burden
shall not be considered a hardship. Modification may be considered
if an alternative standard or approach will provide equal or better
achievement of the purpose of this chapter. A request for modifications
shall be in writing and accompany the stormwater management site plan
submission. The request shall provide the facts on which the request
is based, the provision(s) of this chapter involved and the proposed
modification.
3.
No waiver
or modification of any regulated stormwater activity involving earth
disturbance greater than or equal to one acre may be granted by the
Township unless that action is approved in advance by PADEP or the
Delaware County Conservation District.
4.
For any waiver requests granted from § 19-305, due to poor infiltration soils, a fee-in-lieu payment, as established by the Township, may be required to be paid by the applicant to the Township to offset the new requirements for Township MS-4 stormwater reductions that will be triggered by the waiver.
