No activity regulated by this chapter may commence until the
applicant has received written approval of a SWM site plan from Mahoning
Township.
The SWM site plan and SWM site report shall consist of all applicable
calculations, maps, and plans. All SWM site plan materials shall be
submitted to Mahoning Township in a format that is clear, concise,
legible, neat and well organized; otherwise, the SWM site plan shall
be rejected. Appropriate sections from the Municipal Subdivision and
Land Development Ordinance,[1] and other applicable local ordinances, shall be followed
in preparing the SWM site plan.
A.
A SWM site plan shall include, but not be limited to:
(1)
Plans shall be of one size and in a form that meets the requirements
for recording in the office of the Recorder of Deeds of Montour County.
(2)
The name of the development; name and location address of the property
site; name, address, and telephone number of the applicant/owner of
the property; and name, address, telephone number, email address,
and the seal and signature of the qualified professional preparing
the SWM site plan.
(3)
The date of submission and dates of all revisions.
(4)
A graphical and written scale on all drawings and maps.
(5)
A North arrow on all drawings and maps.
(6)
A location map at a minimum scale of one inch equals 1,000 feet and
illustrates the project relative to highways, municipalities or other
identifiable landmarks.
(7)
Metes and bounds description of the entire tract perimeter.
(9)
Perimeters of existing water bodies within the project area including
stream banks, lakes, ponds, springs, field-delineated wetlands or
other bodies of water, sinkholes, flood hazard boundaries (FEMA-delineated
floodplains and floodways), areas of natural vegetation to be preserved,
the total extent of the upstream area draining through the site, and
overland drainage paths. In addition, any areas necessary to determine
downstream impacts, where required for proposed stormwater management
facilities, must be shown.
(10)
The location of all existing and proposed utilities, on-lot
wastewater facilities, water supply wells, sanitary sewers, and waterlines
on and within 50 feet of property lines including inlets, manholes,
valves, meters, poles, chambers, junction boxes, and other utility
system components.
(11)
A key map showing all existing man-made features beyond the
property boundary that may be affected by the project.
(12)
Soil names and boundaries with identification of the hydrologic
soil group classification, including rock outcroppings.
(13)
Proposed impervious surfaces (structures, roads, paved areas,
and buildings), including plans and profiles of roads and paved areas
and floor elevations of buildings.
(14)
Existing and proposed land use(s).
(15)
Horizontal alignment, vertical profiles, and cross sections
of all open channels, pipes, swales and other BMPs.
(16)
The location and clear identification of the nature of permanent
stormwater BMPs.
(17)
The location of all erosion and sedimentation control facilities,
shown on a separate document from the SWM site plan (typically an
E&S plan).
(18)
The location of easements as requested by Mahoning Township
or where required by this chapter. In lieu of providing an easement
to the public right-of-way, a note may be added to the plan granting
Mahoning Township or its designees access to all easements via the
nearest public right-of-way.
(19)
Construction details for all drainage and stormwater BMPs.
(20)
Identification of short-term and long-term ownership, operations,
and maintenance responsibilities.
(21)
Notes and statements.
(a)
A statement, signed by the landowner, acknowledging that the
stormwater BMPs are fixtures that cannot be altered or removed without
prior approval by Mahoning Township.
(b)
A statement referencing the operation and maintenance (O&M)
agreement and stating that the O&M agreement is part of the SWM
site plan.
(c)
A note indicating that record drawings will be provided for
all stormwater facilities prior to occupancy, or the release of the
surety bond.
(d)
The following signature block for the qualified professional
preparing the stormwater management plan:
|
"I, __________, hereby certify that the Stormwater Management
Plan meets all design standards and criteria of the Mahoning Township's
Stormwater Management Ordinance."
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(e)
The following signature block for the Municipal Engineer reviewing
the stormwater management plan:
|
"I, __________, have reviewed this Stormwater Management Plan
in accordance with the Design Standards and Criteria of the Mahoning
Township's Stormwater Management Ordinance."
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B.
A SWM site report shall include, but not be limited to:
(1)
General data including:
(a)
Project name;
(b)
Project location — address of the property site;
(c)
Name, address, and telephone number of the applicant/owner of
the property;
(d)
Name, address, telephone number, email address, and engineering
seal of the individual preparing the SWM site report;
(e)
Date of submission and revisions.
(2)
Project description narrative that clearly discusses the project
and provides the following information:
(a)
Narrative.
[1]
Statement of the regulated activity describing what is being
proposed. Overall stormwater management concept with description of
permanent stormwater management techniques, including construction
specifications and materials to be used for stormwater management
facilities.
[2]
Expected project schedule.
[3]
Location map showing the project site and its location relative
to release rate districts.
[4]
Detailed description of the existing site conditions including
a site evaluation completed for projects proposed in areas of carbonate
geology or karst topography, and other environmentally sensitive areas
such as brownfields.
[5]
Total site area, pre and post, which must be equal or have an
explanation as to why it is not.
[6]
Total site impervious area.
[7]
Total off-site areas.
[8]
Number and description of stormwater management facilities.
[9]
Type of development.
[10]
Predevelopment land use.
[11]
Whether site is a water quality sensitive (WQS) development.
[12]
Whether site is in a defined sensitive area.
[13]
Types of water quality and recharge systems used, if applicable.
[14]
Complete hydrologic, hydraulic, and structural computations
for all stormwater management facilities.
[15]
A written maintenance plan for all stormwater features, including
detention facilities and other stormwater management elements.
[16]
Identification of ownership and maintenance responsibility for
all permanent stormwater management facilities.
[17]
Other pertinent information, as required.
(b)
Summary tables.
[1]
Predevelopment hydrologic soil group (HSG) assumptions, curve
numbers (CN), computation of average slope, hydraulic length, computed
time of concentration.
[2]
Existing conditions runoff volume and peak rate of runoff.
[3]
Postdevelopment runoff volume and peak rate of runoff.
[4]
Undetained areas, areas to ponds.
[5]
Land use for each subarea.
[6]
Hydrologic soil group (HSG) assumptions, curve numbers (CN).
[7]
Time of concentration computed for each subarea.
[8]
Postdevelopment peak rate of runoff routed to ponds and out.
[9]
Pond maximum return period design data including maximum water
surface elevation, berm elevation, and emergency spillway elevation.
[10]
Water quality depth and volume requirements.
(c)
Calculations.
[1]
Complete hydrologic, hydraulic and structural computations,
calculations, assumptions, and criteria for the design of all stormwater
BMPs.
[2]
Details of the berm embankment and outlet structure indicating
the embankment top elevation, embankment side slopes, top width of
embankment, emergency spillway elevation, perforated riser dimensions,
pipe barrel dimensions and dimensions and spacing of antiseep collars.
[3]
Design computations for the control structures (pipe barrel
and riser, etc).
[4]
A plot or table of the stage-storage (volume vs. elevation)
and all supporting computations.
[5]
Routing computations.
(3)
Reports that do not clearly indicate the above information may be
rejected for review by Mahoning Township and will be returned to the
applicant.
(4)
Description of, justification, and actual field results for infiltration
testing with respect to the type of test and test location for the
design of infiltration BMPs.
(5)
The effect of the project (in terms of runoff volumes, water quality,
and peak flows) on surrounding properties and aquatic features and
on any existing municipal stormwater collection system that may receive
runoff from the project site.
(6)
Description of the proposed changes to the land surface and vegetative
cover including the type and amount of impervious area to be added.
(7)
Identification of short-term and long-term ownership, operation,
and maintenance responsibilities as well as schedules and costs for
inspection and maintenance activities for each permanent stormwater
or drainage BMP, including provisions for permanent access or maintenance
easements.
C.
Supplemental information to be provided prior to recording of the
SWM site plan, as applicable:
(1)
Signed and executed operations and maintenance agreement (Appendix
A[2]).
[2]
Editor's Note: Said Appendix is included at the end of this chapter.
(2)
Signed and executed easements, as required for all on-site and off-site
work.
(3)
An E&S control plan and approval letter from the Montour County
Conservation District.
(4)
A NPDES permit.
(5)
Permits from PADEP and ACOE.
(6)
Geologic assessment.
(7)
Soils investigation report, including boring logs, compaction requirements,
and recommendations for construction of detention basins.
(8)
A highway occupancy permit from PennDOT when utilization of a PennDOT
storm drainage system is proposed or when proposed facilities would
encroach onto a PennDOT right-of-way.
A.
Mahoning Township shall require receipt of a complete SWM site plan
and report as specified in this chapter. Mahoning Township shall review
the SWM site plan and report for consistency with the purposes, requirements,
and intent of this chapter.
B.
Mahoning Township shall not approve any SWM site plan and report
that is deficient in meeting the requirements of this chapter. At
its sole discretion and in accordance with this article, when a SWM
site plan and report is found to be deficient, Mahoning Township may
disapprove the submission and require a resubmission, or, in the case
of minor deficiencies, Mahoning Township may accept submission of
modifications.
C.
Mahoning Township shall notify the applicant in writing within 45
calendar days whether the SWM site plan and report is approved or
disapproved if the SWM site plan and report is not part of a subdivision
or land development plan. If the SWM site plan and report involves
a subdivision or land development plan, the timing shall follow the
subdivision and land development process according to the Municipalities
Planning Code.[1]
[1]
Editor's Note: See 53 P.S. § 10101 et seq.
D.
The Municipal Building Permit office shall not issue a building permit
for any regulated activity if the SWM site plan and report has been
found to be inconsistent with this chapter, as determined by Mahoning
Township. All required permits from PADEP must be obtained prior to
issuance of a building permit.
A modification to a submitted SWM site plan and report for a
development site that involves a change in stormwater management facilities
or techniques, or that involves the relocation or redesign of stormwater
management facilities, or that is necessary because soil or other
conditions are not as stated on the SWM site plan as determined by
Mahoning Township, shall require a resubmission of the modified SWM
site plan in accordance with this chapter.
A disapproved SWM site plan and report may be resubmitted with
the revisions addressing Mahoning Township's concerns documented
in writing to Mahoning Township in accordance with this chapter. The
applicable municipal review fee must accompany a resubmission of a
disapproved SWM site plan and report.
Mahoning Township's approval of a SWM site plan and report
authorizes the regulated activities contained in the SWM site plan
for a maximum term of validity of five years following the date of
approval. Mahoning Township may specify a term of validity shorter
than five years in the approval for any specific SWM site plan. Terms
of validity shall commence on the date Mahoning Township signs the
approval for a SWM site plan. If stormwater management facilities
included in the approved SWM site plan have not been constructed,
or if a record drawing of these facilities has not been approved within
this time, then Mahoning Township may consider the SWM site plan disapproved
and may revoke any and all permits or approvals.
A.
The applicant shall be responsible for providing record drawings
of all stormwater BMPs included in the approved SWM site plan. The
record drawing and an explanation of any discrepancies with the approved
SWM site plan shall be submitted to Mahoning Township as a prerequisite
for the release of the guarantee or issuance of an occupancy permit.
B.
The record drawing shall include a certification of completion signed
by a qualified professional verifying that all permanent stormwater
BMPs have been constructed according to the approved SWM site plan
and report.
(1)
Drawings shall show all approved revisions and elevations and inverts
to all manholes, inlets, pipes, and stormwater control facilities.
C.
After receipt of the record drawing and certification of completion
by Mahoning Township, Mahoning Township may conduct a final inspection.
