For any of the regulated activities of this Part 3, prior to
the final approval of subdivision and/or land development plans, or
the issuance of any permit, or the commencement of any regulated earth
disturbance activity, the owner, subdivider, developer or his agent
shall submit a drainage plan and receive municipal approval of the
plan.
Exemptions from the drainage plan requirements are as specified in §
405-39.
The following items shall be included in the drainage plan:
A. General.
(1) General description of project.
(2) General description of proposed permanent stormwater controls.
(3) The name and address of the project site, the name and address of
the owner of the property and the name of the individual or firm preparing
the drainage plan.
B. Map(s) of the project area showing:
(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. Off-site
drainage areas impacting the project including topographic detail.
(3) Streams, lakes, ponds or other bodies of water within the project
area.
(4) Other features including flood hazard boundaries, existing drainage
swales, wetlands, closed depressions, sinkholes and areas of natural
vegetation to be preserved.
(5) Locations of proposed underground utilities, sewers and water lines.
The locations of all existing and proposed utilities, sanitary sewers
and water lines within 50 feet of property lines of the project site.
(6) An overlay showing soil types and boundaries based on the Lehigh
County Soil Survey, as applicable, latest edition. Any hydric soils
present on the site should be identified as such.
(7) An overlay showing geologic types, boundaries and any special geologic
features present on the site.
(8) Proposed changes to land surface and vegetative cover.
(9) Proposed structures, roads, paved areas and buildings.
(10)
Final contours at intervals of two feet. In areas of steep slopes
(greater than 15%), five-foot contour intervals may be used.
(11)
Stormwater management district boundaries applicable to the
site.
(12)
Clear identification of the location and nature of permanent
stormwater BMPs.
(13)
An adequate access easement around all stormwater BMPs that
would provide municipal ingress to and egress from a public right-of-way.
(14)
A schematic showing all tributaries contributing flow to the
site and all existing man-made features beyond the property boundary
that would be affected by the project.
(15)
The location of all public water supply wells within 400 feet
of the project and all private water supply wells within 100 feet
of the project.
C. Stormwater management controls and BMPs.
(1) All stormwater management controls and BMPs shall be shown on a map
and described, including:
(a)
Groundwater recharge methods such as seepage pits, beds or trenches.
When these structures are used, the locations of septic tank infiltration
areas and wells shall be shown.
(b)
Other control devices or methods such as rooftop storage, semipervious
paving materials, grass swales, parking lot ponding, vegetated strips,
detention or retention ponds, storm sewers, etc.
(2) All calculations, assumptions and criteria used in the design of
the BMPs shall be shown.
(3) All site testing data used to determine the feasibility of infiltration
on a site.
(4) All details and specifications for the construction of the stormwater
management controls and BMPs.
D. The BMP operations and management plan, as required in Article
XI, describing how each permanent stormwater BMP will be operated and maintained and the identity of the person(s) responsible for operations and maintenance. A statement must be included, signed by the landowner, acknowledging that the stormwater BMPs are fixtures that cannot be altered or removed without approval by the municipality.
E. Environmental resources.
(1) An environmental resources site design assessment that describes
the following:
(a)
The extent to which the proposed grading and impervious cover
avoid disturbance of significant environmental resources and preserve
existing site hydrology.
(b)
An assessment of whether alternative grading and impervious
cover site design could lessen the disturbance of significant environmental
resources and/or make better use of the site hydrologic resources.
(c)
A description of how the proposed stormwater management controls
and BMPs serve to mitigate any adverse impacts on environmental resources
on the site.
(2) Significant environmental resources considered in the site design
assessment include, but are not limited to, steep slopes, ponds, lakes,
streams, wetlands, hydric soils, floodplains, riparian vegetation,
native vegetation and special geologic features.
F. The SWM site plan shall provide the following information:
(1) The overall stormwater management concept for the project.
(2) A determination of site conditions in accordance with the BMP Manual
4. A detailed site evaluation shall be completed for projects proposed
in areas of carbonate geology or karst topography, and other environmentally
sensitive areas, such as brownfields.
(3) Stormwater runoff design computations and documentation as specified in this Part
3, or as otherwise necessary to demonstrate that the maximum practicable measures have been taken to meet the requirements of this Part
3, including the recommendations and general requirements in §
405-47.
(4) Expected project time schedule.
(5) A soil erosion and sediment control plan, where applicable, as prepared
for and submitted to the approval authority.
(6) 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 stormwater conveyance system that may be affected
by the project.
(7) Plan and profile drawings of all SWM BMPs, including drainage structures,
pipes, open channels, and swales.
(8) SWM site plan shall show the locations of existing and proposed on-lot
wastewater facilities and water supply wells.
(9) The SWM site plan shall include an O&M plan for all existing
and proposed physical stormwater management facilities. This plan
shall address long-term ownership and responsibilities for O&M
as well as schedules and costs for O&M activities.
(10)
A justification must be included in the SWM site plan if BMPs
other than green infrastructure methods and LID practices are proposed
to achieve the volume, rate and water quality controls under this
Part 3.
A modification to a submitted drainage plan for a proposed development site which involves a change in control methods or techniques, or which involves the relocation or redesign of control measures, or which is necessary because soil or other conditions are not as stated on the drainage plan (as determined by the municipality) shall require a resubmission of the modified drainage plan consistent with §
405-48 subject to review per §
405-49 of this Part
3.
A disapproved SWM site plan may be resubmitted, with the revisions
addressing the Township's concerns, to the Township in accordance
with this article. The applicable review fee must accompany a resubmission
of a disapproved SWM site plan.
The Township's approval of an SWM site plan 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 an SWM site plan. If an approved SWM site plan is not completed according to §
405-55 within the term of validity, then the Township may consider the SWM site plan disapproved and may revoke any and all permits. SWM site plans that are considered disapproved by the Township shall be resubmitted in accordance with §
405-61 of this Part
3.