For any of the regulated activities of this chapter, prior to
the final approval of subdivision and/or land development plans, or
the issuance of any permit, or the commencement of any land disturbance
activity, the owner, subdivider, developer, or agent shall submit
a drainage plan for approval.
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 Township Engineer) shall require a resubmission of the modified drainage plan consistent with §
220-37 subject to review per §
220-38 of this chapter.
Water volume controls shall be implemented using the Design
Storm Method in Subsection A. For regulated activity areas equal or
less than one acre that do not require hydrologic routing to design
the stormwater facilities, this chapter establishes no preference
for either methodology; therefore, the applicant may select either
methodology on the basis of economic considerations, the intrinsic
limitations on applicability of the analytical procedures associated
with each methodology and other factors:
A. The Design Storm Method (CG-1 in the BMP Manual) is applicable to any size of regulated activity. This
method requires detailed modeling based on site conditions:
(1) Do not increase the post-development total runoff volume for all
storms equal to or less than the two-year, twenty-four-hour duration
precipitation; and
(2) For modeling purposes:
(a)
Existing (predevelopment) nonforested pervious areas must be
considered meadow in good condition; and
(b)
Twenty percent of existing impervious area, when present, shall
be considered meadow in good condition in the model for existing conditions.