For any of the activities regulated by this chapter, 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 shall not proceed until the property owner or developer or his/her agent has received written approval of a drainage plan from the Township, except where exempt from the requirement to prepare a drainage plan pursuant to § 132-5 of this chapter. Drainage plans required and approved by the Township shall be on site throughout the duration of the regulated activity.
The drainage plan shall consist of all applicable calculations,
maps, and plans. A note on the maps shall refer to the associated
computations and erosion and sedimentation control plan by title and
date. The cover sheet of the computations and erosion and sedimentation
control plan shall refer to the associated maps by title and date.
All drainage plan materials shall be submitted to the Township in
a format that is clear, concise, legible, neat, and well organized;
otherwise, the drainage plan shall be disapproved and returned to
the applicant. The following items shall be included in the drainage
plan:
A.
General.
(1)
General description of project.
(2)
General description of permanent stormwater management and water
quality techniques, including construction specifications of the materials
to be used for stormwater management facilities.
(3)
Complete hydrologic, hydraulic, and structural computations for all
stormwater management facilities.
(4)
Soil evaluations as they relate to the infiltration device(s) design.
B.
Maps of the project area shall be submitted on twenty-four-inch by
thirty-six-inch sheets and shall be prepared in a form that meets
the requirements for recording in the offices of the Recorder of Deeds
of Montgomery County. The contents of the maps shall include, but
not be limited to:
(1)
The location of the project relative to highways, municipalities
or other identifiable landmarks.
(2)
Existing contours at intervals of two feet. In areas of steep slopes
(greater than 15%), five-foot contour intervals may be used as approved
by the Township Engineer. Critical spot elevations shall be provided
where proposed contours do not provide a sufficient level of detail.
(3)
Existing streams, lakes, ponds, or other bodies of water within the
project area.
(4)
Other physical features, including flood hazard boundaries, sinkholes,
streams, existing drainage courses, 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, including but not limited to electric, gas, CATV, storm sewers, sanitary sewers, and water lines, within 50 feet of property lines shall be shown on the plans. The applicant should submit a plan showing existing features as referenced in § 136-703C of the Subdivision and Land Development Ordinance, Chapter 136.
(6)
An overlay showing soil names and boundaries.
(7)
Proposed changes to the land surface and vegetative cover, including
the type and amount of impervious area that would be added.
(8)
Proposed structures, roads, paved areas, and buildings.
(9)
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.
(10)
The date of submission.
(11)
A graphic and written scale with a minimum scale of one inch
equals 50 feet.
(12)
A North arrow.
(13)
The total tract boundary and size with distances marked to the
nearest foot and bearings to the nearest degree.
(14)
Existing and proposed land use(s).
(15)
A key map showing all existing man-made features beyond the
property boundary that would be affected by the project.
(16)
Horizontal and vertical profiles of all open channels and stormwater
pipe systems, including hydraulic capacity.
(17)
Construction details of proposed stormwater management facilities
shall include the following as applicable:
(a)
Cross sections through the facility showing:
[1]
Side slopes.
[2]
Bottom slopes.
[3]
Embankment with slopes identified.
[4]
Top of berm width and elevation.
[5]
Emergency spillway elevation.
[6]
Cutoff trench with side slopes, depth, and bottom width identified.
[7]
Permanent pool elevation.
[8]
Water quality storm elevation.
[9]
Maximum water surface elevation and infiltration bed lining.
[10]
Outlet structure, outlet pipe, anti-seep collars,
and outfall structure.
(b)
Elevation views of the outlet structure and emergency spillway
showing:
(18)
Overland drainage paths and drainage areas tributary to the
proposed facilities.
(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)
A note on the plan indicating the location and responsibility
for maintenance of the 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 stabilization techniques to be
applied to sinkholes and the location of all notes to be posted, as
specified in this chapter.
(22)
A statement, signed by the landowner, acknowledging the stormwater
management system to be a permanent fixture that can be altered or
removed only after approval of a revised plan by the Township. The
statement shall be incorporated as a deed restriction with proof of
a recorded revised deed submitted to the Township with the as-built
survey for all stormwater management facilities included in the approved
drainage plan.
(23)
The following signature affidavit for the Township must be included
on the plan:
|
"(Township Official or Designee), on
this date ________, has reviewed and hereby concludes that the drainage
plan meets all design standards and criteria of the Towamencin Township
Stormwater Management Ordinance No. ________."
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(24)
The drainage plan shall include an operation and maintenance
plan for all existing and proposed stormwater management/BMP facilities,
addressing long-term ownership and maintenance responsibilities for
such facilities, including schedule for operation and maintenance
activities.
(25)
The location of all erosion and sedimentation control facilities
and BMPs.
C.
Supplemental information.
(1)
A written description of the following information shall be submitted.
(2)
A soil erosion and sedimentation control plan, where applicable,
including all reviews and approvals, as required by the Montgomery
County Conservation District.
(3)
A geologic assessment of the effects of runoff on sinkholes as specified
in this chapter.
(4)
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.
(5)
A declaration of adequacy and highway occupancy permit from the PennDOT
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 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.
(4)
All stormwater management/BMP facility easements required by this
chapter must be shown on the drainage plan, including the bearing
and distance of each segment of the easement's boundary.
For all activities regulated by this chapter, the steps below
shall be followed for submission. For any activities that require
a PADEP joint permit application and regulated under Chapter 105 (Dam
Safety and Waterway Management) or Chapter 106 (Floodplain Management)
of PADEP's Rules and Regulations, require a PennDOT 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 drainage plan shall be submitted by the developer as part of
the development plan submission for the regulated activity. If the
plan is part of a land development or subdivision application, the
plans should be submitted in accordance with the provisions of the
Subdivision and Land Development Ordinance.[1] All other projects should be submitted as referenced in
the following sections.
B.
Four copies of the drainage plan and related application documentation
shall be submitted to the Township. Two copies of the plan will be
forwarded by the Township to the Township Engineer for review.
A.
The Township Engineer shall review the drainage plan for consistency
with this chapter. The Township shall require receipt of a complete
plan, as specified in this chapter.
C.
For activities regulated by this chapter, the Township Engineer shall
notify the Township, in writing, whether the drainage plan is consistent
with this chapter. Should the drainage plan be determined to be consistent
with this chapter, the Township Engineer will forward an approval
letter to the Township with a copy to the developer.
D.
Should the drainage plan be determined to be inconsistent with this
chapter, the Township Engineer will forward a disapproval letter to
the Township with a copy to the developer citing the reason(s) for
the disapproval. Any disapproved drainage plan may be revised by the
developer and resubmitted consistent with this chapter.
E.
For regulated activities specified in § 132-4D(1) through (4) of this chapter, the Township Engineer shall notify the Township, in writing, within a time frame consistent with the Township Building Code and/or Township Subdivision and Land Development Ordinance, of whether the drainage plan is consistent with this chapter and forward a copy of the approval/disapproval letter to the developer. Any disapproved drainage plan may be revised by the developer and resubmitted consistent with this chapter.
F.
For regulated activities requiring a PADEP joint permit application,
the applicant shall request that the Township notify PADEP of whether
the drainage plan is consistent with this chapter and forward a copy
of the review letter to the Township and the developer. PADEP may
consider the Township Engineer's review comments in determining
whether to issue a permit.
G.
The Township shall not approve any subdivision or land development for regulated activities specified in § 132-4D(1) and (2) of this chapter if the drainage plan has been found to be inconsistent with this chapter, as determined by the Township Engineer. All required permits from PADEP must be obtained prior to, or as a condition of, final plan approval.
H.
The Township shall not issue a building permit for any regulated activity specified in § 132-4 of this chapter if the drainage plan has been found to be inconsistent with this chapter, as determined by the Township Engineer, or without considering the comments of the Township Engineer. All required permits from PADEP must be obtained prior to issuance of a building permit.
I.
The Township's approval of a drainage plan prepared in conjunction with a regulated activity that is not a subdivision or land development shall be valid for a period not to exceed one year. This time period shall commence on the date that the Township signs the approved drainage plan. If stormwater management facilities included in the approved drainage plan have not been constructed, or if an as-built survey of these facilities pursuant to § 132-32E of this chapter has not been approved within this time period, the Township may consider the drainage plan disapproved and may revoke any and all permits. Drainage plans that are considered disapproved by the Township shall be resubmitted in accordance with § 132-22 of this chapter.
J.
The Township's approval of a drainage plan prepared in conjunction
with a subdivision or land development shall remain valid and protected
from any change in Township codes and ordinances for a period of five
years from the date of preliminary subdivision and/or land development
plan approval, pursuant to the provisions of the Pennsylvania Municipalities
Planning Code.[2]
[2]
Editor's Note: See 53 P.S. § 10101 et seq.
A.
A modification to a previously submitted drainage plan 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 becomes necessary because soil or other conditions are not as stated on the drainage plan as determined by the Township Engineer, shall require a resubmission of the modified drainage plan consistent with § 132-19 of this chapter and be subject to review as specified in § 132-20 of this chapter.
B.
A modification to an already approved or disapproved drainage plan
shall be submitted to the Township, accompanied by the applicable
review 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 Township review fee.
A disapproved drainage plan may be resubmitted, with the revisions addressing the Township Engineer's concerns documented in writing, to the Township Engineer in accordance with § 132-19 of this chapter and be subject to review as specified in § 132-20 of this chapter. The applicable Township re-review fee must accompany a resubmission of a disapproved drainage plan.
