Any of the activities regulated by this chapter,
the preliminary or final approval of subdivision and/or land development
plans, or the commencement of any regulated earth disturbance activity
may not proceed until the applicant or his/her agent has received
written approval of a drainage plan from the Township Engineer and
an adequate erosion and sediment control plan review by Tredyffrin
Township and the Chester County Conservation District (if required).
The drainage plan shall consist of a general description of the project including sequencing items described in § 174-19, calculations, maps, and plans. A note on the maps shall refer to the associated computations and erosion and sediment control plan by title and date. The cover sheet of the computations, erosion and sediment control plan, and stormwater management plan shall refer to the associated maps by title and date. All drainage plan materials shall be submitted to the Township in a clear and well organized format. The following items shall be included in the drainage plan:
A.
General.
(1)
General description of the project including those areas described in §§ 174-19B and 174-11C(1).
(2)
General narrative and description of proposed permanent
stormwater management techniques, including construction specifications
of the materials to be used for stormwater management facilities.
A description of the effect of the project (in terms of runoff volumes
and peak flows) on adjacent properties and on any existing Township
stormwater collection system that may receive runoff from the project
site is to be included with this submission.
(3)
Complete hydrologic, hydraulic, and structural computations
for all stormwater management facilities.
(4)
An erosion and sediment control plan, including all
reviews, letters of adequacy and approval from the Chester Conservation
District and/or DEP.
(5)
A general description of proposed nonpoint source
pollution controls.
(6)
The drainage plan application and associated fee.
B.
Plans/maps. Plans/map(s) of the project area shall
be submitted on twenty-four-inch-by-thirty-six-inch (maximum of thirty-inch-by-forty-two-inch
if required for clarity) sheets and/or shall be prepared in a form
that meets the requirements for recording at the offices of the Recorder
of Deeds of Chester County. If the SALDO has more stringent criteria
than this chapter, then the more stringent criteria shall apply. The
contents of the map(s) shall include, but not be limited to:
(1)
The location of the project relative to highways,
municipal boundaries, or other identifiable landmarks.
(2)
Existing contours at intervals of two feet.
(3)
Existing streams, lakes, ponds, wetlands or other
waters of the commonwealth within the project area and which may be
impacted by the project and are within 300 feet of the site.
(4)
Other physical features including flood hazard boundaries,
stream buffers, existing drainagecourses, areas of natural vegetation
to be preserved, and the total extent of the upstream area draining
through the site.
(5)
The locations of all existing and proposed utilities,
sanitary and storm sewers, water, gas, and communication lines within
300 feet of property lines.
(6)
An overlay showing soil names and boundaries.
(7)
Limits of earth disturbance (L.O.D.), including the
type and amount of impervious area that is proposed to be added to
the site.
(8)
Proposed structures, roads, paved areas, and buildings.
The total amount of impervious surface to be added shall be shown
on the plan.
(9)
Proposed final contours at intervals of two feet.
(10)
The name of the development, the name and address
of the owner of the property, and the name of the individual or firm
preparing the plan.
(11)
The date of submission.
(12)
A graphic and written scale of one inch equals
no more than 50 feet; for tracts of 20 acres or more, the scale shall
be one inch equals no more than 100 feet.
(13)
A north arrow.
(14)
The total tract boundary and size with distances
marked to the nearest foot and bearings to the nearest degree.
(15)
Existing and proposed land use(s).
(16)
A key map showing all existing human-made features
beyond the property boundary that would be affected by the project.
(17)
Location of all open ditches, drainage channels,
overland drainage patterns and swales.
(18)
When infiltration measures such as seepage pits,
beds, or trenches are used, the locations of existing and proposed
septic tank infiltration areas and wells must be shown. All calculations,
assumptions, and criteria used in the design of the stormwater management
facilities must be shown.
(19)
A twenty-foot-wide access easement around all
stormwater management facilities that would provide ingress to and
egress from a public right-of-way.
(20)
The location of all erosion and sediment control
facilities and all stormwater management facilities.
(21)
In situations where approved stormwater management
facilities are to be located off site, notes shall be provided on
the plans that clearly identify the responsibility for operation and
maintenance of all stormwater management facilities. All off-site
facilities shall meet the performance standards and design criteria
specified in this chapter.
(22)
A statement, signed by the applicant, acknowledging
that:
(23)
The following signature block for the design
engineer: "I, (Design Engineer), on this date (date of signature),
hereby certify that the within referenced drainage plan meets all
design standards and criteria of the Tredyffrin Township Stormwater
Management Ordinance."
C.
Supplemental information.
(1)
A written description of the following information
shall be submitted by the applicant and shall include:
(2)
An erosion and sediment control plan.
(3)
A description of the effect of the project (in terms
of runoff volumes and peak flows) on adjacent properties and on any
existing Township stormwater collection systems that may receive runoff
from the project site.
(4)
A declaration of adequacy and highway occupancy permit
from the Pennsylvania Department of Transportation District Office
when utilization of a PennDOT storm drainage system is proposed.
D.
Stormwater management facilities.
(1)
All stormwater management facilities must be located
on a plan and described in detail.
(2)
When infiltration measures such as seepage pits, beds,
or trenches are used, the locations of existing and proposed septic
tank infiltration areas, wells, foundation walls, steep slopes, streams,
and any other information requested by the Township Engineer must
be shown.
(3)
When infiltration measures such as seepage pits, beds,
or trenches are used, the maximum loading ratios, both impervious
loading and total loading, to the infiltration area should be considered
in the design. Separation from wells, septic system drains, and basement
foundations should also be identified on the stormwater plans.
(4)
All calculations, assumptions, and criteria used in
design of the stormwater management facilities must be shown.
The Township requires receipt of a complete
drainage plan, as specified in this chapter.
A.
Proof of application or documentation of required
permits or approvals for the programs listed below shall be part of
the plan:
(1)
NPDES Permit for Stormwater Discharges from Construction
Activities.
(2)
DEP Joint Permit Application.
(3)
PennDOT Highway Occupancy Permit.
(4)
Chapter 105 (Dam Safety and Waterway Management).
(5)
Chapter 106 (Floodplain Management).
(6)
Any other permit under applicable state or federal
regulations.
B.
The plan shall be coordinated with the state and federal
permit process, where applicable.
C.
For projects that require subdivision or land development
approval, the drainage plan shall be submitted by the applicant as
part of the preliminary plan submission where applicable for the regulated
activity.
D.
For regulated activities that do not require subdivision or land development approval, see § 174-10, General requirements.
F.
Any submissions to the agencies listed above that
are found to be incomplete shall not be accepted for review and shall
be returned to the applicant with a notification in writing of the
specific manner in which the submission is incomplete.
A.
The Township Engineer shall review the drainage plan
for compliance with the provisions of this chapter.
B.
The Township Engineer shall review the drainage plan
for any subdivision or land development for compliance with the Township's
SALDO provisions not otherwise superseded by this chapter.
C.
The Chester County Conservation District, in accordance
with established criteria and procedures, will review the drainage
plan for consistency with stormwater management and erosion and sediment
pollution control requirements and provide comments to the Township.
Such comments shall be considered by the Township prior to final approval
of the drainage plan.
D.
For activities regulated by this chapter, the Township
Engineer shall notify the applicant in writing, within 90 calendar
days of submission of the drainage plan, whether the drainage plan
is consistent with the provisions of this chapter.
E.
For regulated activities under this chapter that require
a NPDES permit application, the applicant shall forward a copy of
the Township Engineer's review letter with comments regarding the
drainage plan to the Conservation District. DEP and the Conservation
District may consider the Township Engineer's review comments in determining
whether to issue a permit.
F.
The Township will not grant preliminary or final approval to any subdivision or land development for regulated activities specified in § 174-7 if the drainage plan has been found by the Township Engineer to be noncompliant with this stormwater management ordinance. All required permits from DEP must be obtained prior to approval of any subdivision or land development.
G.
No building permits for any regulated activity specified in § 174-7 shall be approved by the Township if the drainage plan has been found to be noncompliant with this stormwater management chapter, as determined by the Township Engineer and Chester County Conservation District, or without considering the comments of the Township Engineer and Chester County Conservation District. All required permits from DEP must be obtained by the applicant prior to issuance of a building permit.
H.
The applicant shall be responsible for completing
as-built drawings of all stormwater management facilities included
in the approved drainage plan. The as-built drawings and an explanation
of any discrepancies with the design plans shall be submitted to the
Township Engineer for final approval within 60 days of completion.
As-built plans must be submitted to the Township Engineer prior to
issuance of a use and occupancy permit.
I.
Tredyffrin Township will not approve the record drawing
until it receives a copy of an approved declaration of adequacy and/or
highway occupancy permit from the PennDOT District Office, NPDES permit,
and any other applicable permits or approvals from DEP or the Conservation
District. The above permits and approvals must be based on the record
drawings.
J.
The Township's approval of a drainage plan shall be valid for a period not to exceed five years commencing on the date of final approval of the project and the approved drainage plan. If stormwater management facilities included in the approved drainage plan have not been constructed, then the Township may consider the drainage plan noncompliant and may revoke any and all permits. Drainage plans that are determined to be noncompliant by the Township shall be resubmitted in accordance with § 174-15.
A.
A modification to a submitted drainage plan under review by the Township for a development site that involves the following shall require a resubmission to the Township of a modified drainage plan and applicable review and inspection fee consistent with § 174-12 and be subject to review as specified in § 174-13:
B.
A modification to an already approved or noncompliant
drainage plan shall be submitted to the Township, accompanied by the
applicable review and inspection fee. A modification to a drainage
plan for which a formal action has not been taken by the Township
shall be submitted to the Township accompanied by the applicable review
and inspection fee.
An inconsistent or noncompliant drainage plan may be resubmitted with the revisions addressing the Township's concerns documented in writing. One full copy of the plan package shall include all changes highlighted in yellow and/or tabbed when located within a report. It must be addressed to the Township Engineer in accordance with § 174-12, distributed accordingly, and be subject to review as specified in § 174-13. The applicable review and inspection fee must accompany a resubmission of an inconsistent or noncompliant plan.
