[Ord. No. 383, 8/27/2019]
For any of the activities regulated by this chapter and not eligible for the exemptions provided in §
26-302, the final approval of subdivision and/or land development plans, the issuance of any building or occupancy permit, or the commencement of any land disturbance activity, may not proceed until the applicant has received written approval of a SWM site plan from the Township.
[Ord. No. 383, 8/27/2019]
1. 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 the Township in a format that is clear, concise, legible,
neat and well organized; otherwise, the SWM site plan shall be rejected.
2. Appropriate sections from the Municipal Subdivision and Land Development
Ordinance, and other applicable local ordinances, shall be followed
in preparing the SWM site plan.
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 Washington
County.
(a)
Plans for tracts of less than 20 acres shall be drawn at a scale
of one inch equals no more than 50 feet;
(b)
Plans for tracts of 20 acres or more, plans shall be drawn at
a scale of one inch equals no more than 100 feet;
(c)
Lettering shall be drawn to a size to be legible if the plans
are reduced to 1/2 size.
(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 engineering seal of the individual 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.
(8)
Existing and final contours at intervals:
(a)
Slopes less than 5%: no greater than one foot;
(b)
Slopes between 5% and 15%: no greater than two feet;
(c)
Steep slopes (greater than 15%): five-foot contour intervals
may be used.
(9)
A stream and wetland delineation report prepared by a qualified
professional must be provided. Perimeters of existing waterbodies
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 water
lines 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 Hydraulic
Soil Group classification including rock outcroppings.
(13)
Geotechnical report indicating subsurface conditions that may
affect stream pollution (such as the presence of deep mines), slope
stability analysis for all proposed embankments associated with stormwater
BMPs, boring logs in the location of proposed stormwater BMPs, compaction
requirements, and recommendations for construction of basins or subsurface
BMPs (such as keyway size, embankment slope, maximum depth of excavation,
etc.). In addition to the slope stability analysis provided prior
to construction, an additional slope stability analysis must be performed
on all constructed embankments and provided to the Township.
(14)
Proposed impervious surfaces (structures, roads, paved areas,
and buildings), including plans and profiles of roads and paved areas
and floor elevations of buildings.
(15)
Existing and proposed land use(s).
(16)
Horizontal alignment, vertical profiles, and cross sections
of all open channels, pipes, swales and other BMPs where required
by the Township.
(17)
The location and clear identification of the nature of permanent
stormwater BMPs.
(18)
The location of all erosion and sedimentation control facilities,
shown on a separate from the SWM site plan (typically an E&S plan).
(19)
A minimum twenty-foot-wide access easement along with a twenty-foot ingress to and egress from a public right-of-way. Easements for stormwater BMPs shall conform with §
26-901 of this chapter. Subsurface facilities shall have riser structures and cleanout ports that are accessible and unobstructed by parked vehicles or any item which may prohibit maintenance and inspection.
(20)
Construction details for all drainage and stormwater BMPs.
(22)
Identification of short-term and long-term ownership, operations,
and maintenance responsibilities.
(23)
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 the 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)
At the discretion of the Township, 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 registered professional
engineer preparing the stormwater management plan:
"I, ___ (NAME) _____, hereby certify that the Stormwater Management
Plan meets all design standards and criteria of the North Strabane
Township Stormwater Management Ordinance."
(e)
The following signature block for the Township Engineer reviewing
the stormwater management plan:
"I, ___ (NAME) _____ have reviewed this Stormwater Management
Plan in accordance with the Design Standards and Criteria of the North
Strabane Township Stormwater Management Ordinance."
B. SWM site report shall include (but not limited to):
(1)
General data including:
(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, where applicable:
(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. This may be included in the geotechnical report.
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.
8)
Number and description of stormwater management facilities.
10) Pre-development land use.
11) Whether site is in a defined sensitive area.
12) Types of water quality and recharge systems used,
if applicable.
13) Complete hydrologic, hydraulic, and structural
computations for all stormwater management facilities.
14) A written maintenance plan for all stormwater features
including detention facilities and other stormwater management elements.
15) Identification of ownership and maintenance responsibility
for all permanent stormwater management facilities.
16) Other pertinent information, as required.
(b)
Summary Tables.
1)
Pre-development 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)
Post-development 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)
Post-development peak rate of runoff routed to and out of ponds.
9)
Pond maximum return period design data including maximum water
surface elevation, berm elevation, and emergency spillway elevation,
and provided freeboard for emergency spillway analysis.
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)
Design computations for emergency spillway analysis (100-year,
twenty-four-hour storm with riser inoperable).
5)
A plot or table of the stage-storage (volume vs. elevation)
and all supporting computations.
(d)
Drawings.
1)
Drainage area maps for all watersheds and inlets depicting the
time of concentration path for both existing conditions and post-developed
condition.
2)
All stormwater management facilities must be located on a plan
and described in detail including easements and buffers boundaries.
(3)
Reports that do not clearly indicate the above information shall
be rejected for review by the 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. Infiltration testing must be
provided herewith and may not be performed at a later date, if infiltration
BMPs are proposed. Infiltration testing must be performed in-situ
at the proposed bottom elevation of stormwater 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 requested by the Township:
(1)
Signed and executed operations and maintenance agreement (Appendix
A).
(2)
Signed and executed easements, as required for all on-site and
off-site work.
(3)
An erosion and sedimentation control plan and approval letter
from the Washington County Conservation District.
(5)
Permits from PADEP and ACOE.
(7)
On-site inspection reports from contractor and/or geotechnical
engineer, including boring logs, compaction test results, and on-site
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, or when drainage is directed
toward a PennDOT right-of-way.
[Ord. No. 383, 8/27/2019]
1. The applicant shall submit the SWM site plan and report for the regulated
activity.
2. Two copies of the SWM site plan and report shall be submitted and
be distributed as follows:
A. One copy to the Township accompanied by the requisite executed review
fee reimbursement agreement, as specified in this chapter.
B. One copy to the Township Engineer.
3. Additional copies shall be submitted as requested by the Township
or other government agencies.
[Ord. No. 383, 8/27/2019]
1. The Township shall require receipt of a complete SWM site plan and
report as specified in this chapter. The Township shall review the
SWM site plan and report for consistency with the purposes, requirements,
and intent of this chapter.
2. The 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 Part, when a SWM site plan
and report is found to be deficient, the Township shall disapprove
the submission and require a resubmission, or in the case of minor
deficiencies, the Township may accept submission of modifications.
3. The 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.
4. 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 the Township.
All required permits from PADEP must be obtained prior to issuance
of a building permit.
[Ord. No. 383, 8/27/2019]
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 re-design 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
the Township, shall require a resubmission of the modified SWM site
plan in accordance with this chapter. Proof of resubmission to the
Conservation District is required, and to DEP or PennDOT if their
approval is required.
[Ord. No. 383, 8/27/2019]
A disapproved SWM site plan and report shall be resubmitted
with the revisions addressing the Township's concerns documented,
in writing, to the Township in accordance with this chapter. The applicable
municipal review fee must accompany a resubmission of a disapproved
SWM site plan and report.
[Ord. No. 383, 8/27/2019]
The 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. The
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 the 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 the
Township shall consider the SWM site plan disapproved and shall revoke
any and all permits or approvals.
[Ord. No. 383, 8/27/2019]
1. The applicant shall be required to provide 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 the Township as a prerequisite
for the release of the guarantee or issuance of an occupancy permit.
2. 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.
A. Drawings shall show all approved revisions and elevations and inverts
to all manholes, inlets, pipes, and stormwater control facilities.
B. Submission shall include a comparison of the constructed stage-storage
(volume vs. elevation) of all aboveground and below-ground stormwater
storage facilities to the approved design.
C. Elevations of stormwater BMP top of embankment and emergency spillway
shall be taken as the lowest elevation at which water will begin to
overflow. It shall not be acceptable to take an average of surveyed
data points for the purpose of reporting as-built elevations.
D. Basin bottom elevation shall be reported as the lowest elevation
in the basin. If the basin is proposed to be filled with aggregate
or media, the basin bottom shall be reported as the surface elevation
of this media, so long as the thickness of the media is indicated
on the drawing.
E. All proposed design criteria for stormwater BMPs must be measured
and reported, such as width of embankment, top of riser, orifice or
weir size and elevations, and underdrain size and locations.
3. After receipt of the record drawing and certification of completion
by the Township, the Township shall conduct a final inspection.
4. As-Built Drawings.
A. Upon completion of the construction within a land development or
construction of improvements in a subdivision, the applicant shall
furnish the Township with an electronic file in PDF format of the
plan.
B. Such "as-built" drawings shall include the following items where
applicable:
(1)
Scale, North arrow and date;
(2)
Tract boundary and lot lines;
(3)
Road access, public and private internal roads and walks;
(4)
Plan view and vertical profiles of new public streets;
(5)
Stormwater management to include:
(a)
Location of detention facilities including measurements as required
to verify as-built volume.
(b)
Location of outflow structures including measurements of controls.
(c)
Location and size of emergency spillways.
(d)
Location of all best management practices (BMPs) including but
not limited to sumps, vegetative swales, bio-swales, ditches and sediment
forebays.
(6)
Locations of drainage structures and pipes, including type and
profiles;
(7)
Utility easements, including sanitary sewer;
(8)
Parking area and number of spaces;
(9)
Location of all buildings;
(10)
Statement to the effect that all utilities are located within
the proper rights-of-way for roads to be considered for acceptance
by the Township;
(13)
Location of trash facilities.