The stormwater management plan shall consist
of all applicable calculations, maps, and plans. A note on the maps
shall refer to the associated computations and erosion and sediment
pollution control plan by title and date. The cover sheet of the computations
and erosion and sediment pollution control plan shall refer to the
associated maps by title and date. All stormwater management plan
materials shall be submitted to the municipality in a format that
is clear, concise, legible, neat, and well organized; otherwise, the
stormwater management plan shall be disapproved and returned to the
applicant. Said plan shall be prepared by a registered professional
land surveyor, qualified geologist, landscape architect, architect,
or engineer licensed in the State of Pennsylvania, with said preparer's
seal and registration number affixed to the plan. The following items
shall be included in the stormwater management plan:
A. Stormwater management report:
(1) General description of project.
(2) General description of permanent stormwater management
techniques, including construction specifications and materials to
be used for stormwater management facilities.
(3) Complete hydrologic, hydraulic, and structural computations
for all stormwater management facilities.
(4) A written maintenance plan for all stormwater features,
including detention facilities and other stormwater management elements.
(5) Identification of ownership and maintenance responsibility
for all permanent stormwater management facilities.
(6) Narrative requirement.
(a)
The stormwater management report must include
a narrative which clearly discusses the project and summary tables
which, at a minimum, provides the following information:
[1]
Narrative:
[a] The overall stormwater management
concept.
[b] The expected project schedule.
[d] Total site area, pre and post,
which must be equal or have an explanation as to why it is not.
[e] Total site impervious area.
[g] Number of stormwater management
facilities (ponds), if applicable.
[j] Whether site is underlain by carbonate
geology.
[k] Whether site is a water quality
sensitive (WQS) development.
[l] Whether site is in a defined sensitive
area.
[m] Types of water quality and recharge
systems used, if applicable.
[n] Other pertinent information, as
required.
[2]
Summary tables:
[a] Predevelopment:
[i] Hydrologic soil group (HSG) assumptions,
curve numbers (CN).
[ii] Computation of average slope,
hydraulic length, computed time of concentration.
[iii] Required peak rate of runoff.
[b] Postdevelopment:
[i] Undetained areas, areas to ponds.
[ii] Land use for each subarea.
[iii] Hydrologic soil group (HSG) assumptions,
curve numbers (CN).
[iv] Time of concentration computed
for each subarea.
[v] Postdevelopment peak rate of runoff
routed to ponds and out.
[vi] Pond maximum return period design
data, including: maximum water surface elevation, berm elevation,
and emergency spillway elevation.
[vii] Water quality depth and volume
requirements.
[viii] Recharge volume requirements.
[x] Capture volumes required.
[xi] Reports that do not clearly indicate
the above information may be rejected for review by the municipality's
engineer or representative and will be returned to the applicant.
B. Plan requirements. Plans for tracts of less than 20
acres shall be drawn at a scale of one inch equals no more than 50
feet; for tracts of 20 acres or more, plans shall be drawn at a scale
of one inch equals no more than 100 feet. Plans shall be submitted
on the following sheet sizes: 18 feet by 24 inches, 24 inches by 36
inches, or 36 inches by 42 inches. All lettering shall be drawn to
a size to be legible if the plans are reduced to half size. All sheets
comprising a submission shall be on one size. The following information,
unless specifically exempted in writing by the Municipal Engineer,
must be shown on the plans, prepared in a form which meets the requirements
for recording in the Office of the Recorder of Deeds of Centre County,
Pennsylvania. The contents of the map(s) shall include, but not be
limited to:
(1) 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.
(2) The date of submission and revision.
(3) The location of the project relative to highways,
municipalities or other identifiable landmarks.
(4) Existing contours at intervals of two feet. In areas
of steep slopes (greater than 15%), five-foot contour intervals may
be used.
(5) Existing streams, lakes, ponds, or other bodies of
water within the project area.
(6) Other physical features, including flood hazard boundaries,
sinkholes, closed depressions, wetlands, streams, existing drainage
courses, areas of natural vegetation to be preserved, and the total
extent of the upstream area draining through the site. In addition,
any areas necessary to determine downstream impacts, where required
for proposed stormwater management facilities must be shown.
(7) The locations of all existing and proposed utilities,
sanitary sewers, and water lines within 20 feet of property lines.
(8) An overlay showing soil names and boundaries, including
rock outcrops.
(9) Total area of impervious surfaces proposed.
(10)
Proposed structures, roads, paved areas, and
buildings.
(11)
Final contours at intervals of two feet. In
areas of steep slopes (greater than 15%), five-foot contour intervals
may be used.
(12)
A graphic and written scale.
(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 man-made features
beyond the property boundary that would be affected by the project
and the extent of the watershed or subarea that drains through the
project site.
(17)
Horizontal and vertical profiles of all open
channels, including hydraulic capacity.
(19)
Access easements around all stormwater management
facilities that would provide ingress to and egress from a public
right-of-way.
(20)
A note on the plan indicating the location and
responsibility for maintenance of stormwater management facilities
that would be located off site. All off-site facilities shall meet
the performance standards and design criteria specified in this chapter.
(21)
A construction detail of any improvements made
to sinkholes and the location of all notes to be posted, as specified
in this chapter.
(22)
Complete drainage systems for the site, including
details for construction. All existing drainage features, which are
to be incorporated in the design, shall be so identified. If the site
is to be developed in stages, a general stormwater management plan
for the entire site shall be presented with the first stage and appropriate
development stages for the drainage system shall be indicated.
(23)
Location and selected plan material used for
vegetative filter paths to sinkholes, and the location of all notices
to be posted.
(24)
A statement, signed by the landowner, acknowledging
the stormwater management system is to be maintained in accordance
with the approved ownership and maintenance program and remain a permanent
fixture that can be altered or removed only after approval of a revised
plan by the municipality.
(25)
A note indicating that as-built drawings will
be provided by the developer for all stormwater facilities prior to
occupancy or the release of the surety bond.
(26)
The following signature block for the registered
professional preparing the stormwater management plan:
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"I, ______________________, hereby certify that
the stormwater management plan meets all design standards and criteria
of the Halfmoon Township Stormwater Management Ordinance."
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(27)
The following signature block for the Township
Engineer reviewing the stormwater management plan:
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"I, _____________________, have reviewed this
stormwater management plan in accordance with the design standards
and criteria of the Halfmoon Township Stormwater Management Ordinance."
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(28)
The location of all erosion and sedimentation
control facilities.
C. Supplemental information:
(1) A soil erosion and sediment pollution control plan,
where applicable, including all reviews and approvals, as required
by PA DEP.
(2) Soils investigation report, including boring logs,
compaction requirements, and recommendations for construction of detention
basins.
(3) Karst features identification and analysis reports
and a hydrogeologic assessment of the effects of runoff on sinkholes.
(4) The effect of the project (in terms of runoff volumes
and peak flows) on adjacent properties and on any existing municipal
stormwater collection system that may receive runoff from the project
site.
(5) A declaration of adequacy and highway occupancy permit
from the PA DOT District Office when utilization of a PA DOT storm
drainage system is proposed.
(6) All permits required by the Pennsylvania Department
of Environmental Protection, Army Corps of Engineers and other regulatory
agencies.
D. Stormwater management facilities.
(1) All stormwater management facilities must be located
on a plan and described in detail.
(2) When groundwater recharge methods, such as seepage
pits, beds or trenches are used, the locations of existing and proposed
septic tank infiltration areas and wells must be shown.
(3) All calculations, assumptions, and criteria used in
the design of the stormwater management facilities must be shown.
(a)
A sketch 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.
(b)
Design computations for the pipe barrel and
riser.
(c)
A plot or table of the stage-storage (acre-feet
vs. elevation) and all supporting computations.
(d)
Flood routing computations.
(e)
A detailed plan of the trash rack and antivortex
device.
(4) Record set (as-built) plans. At the completion of
the project, and as a prerequisite for the release of the guarantee
or issuance of an occupancy permit, the owner or his representative
shall:
(a)
Provide certification of completion from a registered
professional verifying that all permanent facilities have been constructed
according to the plans and specifications and approved revisions thereto;
and
(b)
Provide a set of approved stormwater management
plan drawings showing all approved revisions and elevations and inverts
to all manholes, inlets, pipes, and stormwater control facilities.
For all activities regulated by this chapter,
the steps below shall be followed for submission. For any activities
that require a PA DEP joint permit application and regulated under
Chapter 105 (Dam Safety and Waterway Management) or Chapter 106 (Floodplain
Management) of PA DEP's rules and regulations, require a PA DOT highway
occupancy permit, or require any other permit under applicable state
or federal regulations, the permit(s) shall be part of the plan.
A. The stormwater management plan shall be submitted
by the developer as part of the preliminary plan submission for the
regulated activity.
B. Four copies of the stormwater management plan and
stormwater management report shall be submitted.
C. Distribution of the stormwater management plan will
be as follows:
(1) Two copies to the municipality accompanied by the
requisite municipal review fee, as specified in this chapter.
(2) One copy to the Municipal Engineers.
(3) One copy to the County Planning Commission/Department.
A disapproved stormwater management plan may be resubmitted, with the revisions addressing the Municipal Engineer's concerns documented, in writing, to the Municipal Engineer in accordance with §
200-23 of this chapter and be subject to review as specified in §
200-24 of this chapter. The applicable municipality review fee must accompany a resubmission of a disapproved stormwater management plan.