A.
This chapter shall apply to all watersheds and areas
in Tredyffrin Township. Additional standards for peak rate of runoff
control shall apply if they are more stringent for areas within certain
watersheds, subject to an adopted Act 167 Plan.
B.
This chapter shall only apply to temporary erosion
and sediment control measures and all permanent structural and nonstructural
stormwater management BMPs constructed as part of any of the regulated
activities listed in this section.
C.
The following activities shall be regulated by this chapter unless exempted by § 174-8:
(1)
Subdivisions.
(2)
Land developments.
(3)
Redevelopments.
(4)
Construction of proposed, new or additional impervious
surfaces (driveways, parking lots, roads, etc.).
(5)
Construction of proposed buildings or additions to
existing buildings.
(6)
Alteration of the natural hydrologic regime.
(7)
Diversion, piping or encroachments in any natural
or human-made drainage channel.
(8)
Installation of nonstructural and structural stormwater
management BMPs or appurtenances thereto.
(9)
Earth disturbance activities, whether or not they
are associated with a development or redevelopment project, of greater
than 5,000 square feet where slopes less than or equal to 15% are
impacted by grading, disturbance or construction activities.
(10)
Earth disturbance activities, whether or not
they are associated with a development or redevelopment project, of
greater than 1,000 square feet where slopes greater than 15% are impacted
by proposed grading, disturbance or construction activities.
(11)
Earth disturbances within 50 feet of other sensitive
environmental features, such as streams, ponds, lakes and wetlands.
(12)
Any of the above regulated activities which
were approved more than five years prior to the effective date of
this chapter (date of adoption) and resubmitted for municipal approval.
D.
Table 7.1 summarizes the applicability requirements.
"Proposed Impervious Surface" in Table 7.1 includes new, additional,
or replacement impervious surface/cover. Repaving existing surfaces
without reconstruction does not constitute "replacement."
|
TABLE 7.1
| |||||||
|---|---|---|---|---|---|---|---|
|
APPLICABILITY
| |||||||
|
Type of Project
|
Proposed Impervious Surface
|
Earth Disturbance
| |||||
|
0 - 499 square feet
|
500 - 1,000 square feet
|
>1,000 square feet
|
>1 acre
|
5,000 square feet to 1 acre
|
>1 acre
| ||
|
Article IV, Drainage Plan Requirements
|
Development
|
Exempt
|
Modified
|
Yes
|
Yes
|
Yes
|
Yes
|
|
Redevelopment
|
Exempt
|
Modified
|
Yes
|
Yes
|
Yes
|
Yes
| |
|
§ 174-19, Nonstructural project design
|
Development
|
Exempt
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
|
Redevelopment
|
Exempt
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
| |
|
§ 174-20, Groundwater recharge
|
Development
|
Exempt
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
|
Redevelopment
|
Exempt
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
| |
|
§ 174-21, Water quality requirements
|
Development
|
Exempt
|
Exempt
|
Yes
|
Yes
|
n/a
|
Yes
|
|
Redevelopment
|
Exempt
|
Exempt
|
Yes
|
Yes
|
n/a
|
Yes
| |
|
§ 174-22, Stream bank erosion requirements
|
Development
|
Exempt
|
Exempt
|
Yes
|
Yes
|
n/a
|
Yes
|
|
Redevelopment
|
Exempt
|
Exempt
|
Yes
|
Yes
|
n/a
|
Yes
| |
|
§ 174-23, Stormwater peak rate control and management standards
|
Development
|
Exempt
|
Exempt
|
Yes
|
Yes
|
Yes
|
Yes
|
|
Redevelopment
|
Exempt
|
Exempt
|
Yes
|
Yes
|
Yes
|
Yes
| |
|
Erosion and sediment pollution control
(E&SC) plan
|
Earth disturbance
|
See earth disturbance requirements
|
See earth disturbance requirements
|
See earth disturbance requirements
|
See earth disturbance requirements
and NPDES permit requirements
|
Yes
|
Yes
|
|
0 - 5,000 square feet: No SWG permit
required from Township, but E&SC BMPs required to be implemented
on site
0 - 1,000 square feet: SWG permit required
from Township, with E&SC plan and BMPs if impacts slopes >15%
5,000 square feet: 1 acre — SWG
permit required from Township, with E&SC plan and BMPs
Greater than 1 acre: SWG permit required
from Township, and NPDES permit required from CCCD and/or DEP
(Refer to municipal earth disturbance
requirements)
| |||||||
|
LEGEND:
| |
|
Yes — Drainage plan
with stormwater management controls necessary to meet the section
provision.
| |
|
Exempt — Exempt
from required section provision. Drainage plan submission may still
be required if other section provisions are applicable (yes in box).
| |
|
Modified Drainage Plan — For sites with 500 square feet to 1,000 square feet of proposed impervious surfaces. This stormwater and grading permit (SWG) shall follow the groundwater recharge requirements found in § 174-20C(1)(b)[1].
| |
|
E&SC Plan —
Erosion and sediment control pollution plans are required for earth
disturbances greater than 5,000 square feet. E&SC plans are also
required for earth disturbances greater than 1,000 square feet if
impacts to slopes >15%.
|
A.
Exemptions for land use activities. The following
land use activities are exempt from the drainage plan submission requirements
of this chapter:
(1)
Use of land for gardening for home consumption.
(2)
Agricultural activity when operated in accordance
with a conservation plan, nutrient management plan, or erosion and
sedimentation control plan approved by the County Conservation District.
Installation of new or expansion of existing farmsteads, animal housing,
waste storage, and production areas having a net increase of impervious
surfaces greater than 1,000 square feet shall be subject to the provisions
of this chapter.
(3)
Forestry operations which are following the Department of Environmental Protection's (DEP) management practices contained in its publication "Soil Erosion and Sedimentation Control Guidelines for Forestry," operating under an approved erosion and sedimentation plan and complying with the stream buffer requirements in § 174-21J.
(4)
Roadway replacement, development, or redevelopment
that has less than 2,000 square feet of new, additional, or replaced
impervious surface/cover, or in the case of earth disturbance only,
less than 5,000 square feet of disturbance.
(5)
Proposed improvements not exceeding 499 square feet
and where the total cumulative square footage of all impervious surfaces
does not exceed the impervious surface standards of the applicable
zoning district.
(6)
Maintenance to any existing stormwater management
system made in accordance with plans and specifications approved by
the Township Engineer.
(7)
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 Engineer within two calendar days of the commencement
of the activity. If the Township Engineer finds that the work is not
an emergency, then the work shall cease immediately and the requirements
of this chapter shall be addressed as applicable.
(8)
Replacement of residential impervious coverage listed
below is exempt from the provisions of this chapter:
(a)
Repair, maintenance, replacement, and/or resurfacing
of existing asphalt, concrete, or impervious driveways. Relocation
of existing driveways or reconstruction of driveways proposing additional
impervious coverage exceeding 499 square feet are not exempt from
the provisions of this chapter.
(b)
Repair, maintenance, or replacement of existing
stone, concrete, or impervious patios, wooden or composite decks,
and sidewalks. Relocation of existing decks, patios, or sidewalks,
or reconstruction proposing additional impervious coverage exceeding
499 square feet, is not exempt from the provisions of this chapter.
(c)
Repair or maintenance to existing building structures,
including interior and exterior renovations. Proposed building replacement
projects, including complete rebuilds or partial knock-down rebuilds
exceeding 499 square feet are not exempt from the provisions of this
chapter.
(9)
Resurfacing and/or milling and resurfacing of existing
roadway and highway impervious surfaces without reconstruction.
B.
Exemptions for development activities.
(1)
The following development and earthmoving activities
are exempt from the drainage plan submission requirements of this
chapter:
(2)
These criteria shall apply to the total development
even if the development is to take place in phases. The date of the
chapter adoption shall be the starting point from which to consider
tracts as "parent tracts" upon which future land development activities
and respective earth disturbance computations shall be cumulatively
considered.
C.
Agricultural related activities.
[Added 10-7-2019 by Ord.
No. HR-430[1]]
(1)
High tunnels (as defined in Article II) if:
(a)
The high tunnel or its flooring does not result in an impervious
area exceeding 25% of all structures located on the owner's total
contiguous land area; and
(b)
The high tunnel meets one of the following:
[1]
The high tunnel is located at least 100 feet from any perennial
stream or watercourse, public road or neighboring property line;
[2]
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%; or
[3]
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 this chapter.
[1]
Editor's Note: This ordinance also redesignated former Subsection
C as Subsection D.
D.
Additional exemption criteria.
(1)
Exemption responsibilities. An exemption shall not
relieve the applicant from implementing such measures as are necessary
to protect public health, safety, and property.
(2)
HQ and EV streams. An exemption shall not relieve the applicant from meeting the special requirements for watersheds draining to identified high quality (HQ) or exceptional value (EV) waters and source water protection areas (SWPA) and requirements for nonstructural project design sequencing (see § 174-19).
(3)
Drainage problems. If a drainage problem is documented
or known to exist downstream of or is expected to result from the
proposed activity, then the Township may require the applicant to
comply with this chapter.
(4)
Exemptions from provisions of this chapter still require
compliance with all other applicable regulations.
A.
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.
B.
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.).
