Exemptions from any provisions of this chapter shall not relieve the applicant from the requirements in §
395-13D through
K.
A. Regulated activities that result in cumulative earth disturbances
of less than 6,000 square feet are exempt from the requirements.
B. Agricultural activity is exempt from the SWM site plan preparation
requirements of this chapter provided the activities are performed
according to the requirements of 25 Pa. Code Chapter 102.
C. Forest management and timber operations are exempt from the SWM site
plan preparation requirements of this chapter provided the activities
are performed according to the requirements of 25 Pa. Code Chapter
102.
D. The municipality may deny or revoke any exemption pursuant to this
section at any time for any project that the municipality believes
may pose a threat to public health and safety or the environment.
The green infrastructure and low-impact development practices
provided in the BMP Manual shall be utilized for all regulated activities wherever
possible. Water volume controls shall be implemented using the Design
Storm Method in Subsection A or the Simplified Method in Subsection
B below. 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 postdevelopment total runoff volume for all storms
equal to or less than the two-year twenty-four-hour-duration precipitation.
(2) For modeling purposes:
(a)
Existing (predevelopment) nonforested pervious areas must be
considered meadow in good condition.
(b)
Twenty percent of existing impervious area, when present, shall
be considered meadow in good condition in the model for existing conditions.
If constructing facilities to accommodate the resulting volume requirement
is believed by the developer to be unfeasible on site, the developer
may submit a modification request along with technical support documentation
for review by the Borough. The Borough may grant a modification to
alternatively construct off-site volume controls providing that the
alternative site is located within the same subwatershed as the project
site and the peak discharge rates downstream of the project site are
not increased above predevelopment magnitudes.
[1]
Design and construction of the off-site controls shall be subject
to review and approval by the Borough. Costs shall be the responsibility
of the developer. Design documentation shall demonstrate that the
proposed facilities are effective in removing an amount equal to the
project's increase in the two-year storm volume from the overall
runoff where the facility is to be located.
[2]
In lieu of construction of off-site controls, the developer
may request, and the Borough may accept, the payment into a stormwater
fund. The cost shall be based upon the Borough's current fee
schedule (adjusted annually) based upon an established cost per cubic
foot of storage.
B. The Simplified Method (CG-2 in the BMP Manual) provided below is independent of site conditions and
should be used if the Design Storm Method is not followed. This method
is not applicable to regulated activities greater than one acre or
for projects that require design of stormwater storage facilities.
Twenty percent of existing impervious area, when present, shall be
considered meadow in good condition. Then, for new (additional) impervious
surfaces:
(1) Stormwater facilities shall capture at least the first two inches
of runoff from all new impervious surfaces.
(2) At least the first one inch of runoff from new impervious surfaces
shall be permanently removed from the runoff flow, i.e., it shall
not be released into the surface waters of this commonwealth. Removal
options include reuse, evaporation, transpiration, and infiltration.
(3) Wherever possible, infiltration facilities should be designed to
accommodate infiltration of the entire "permanently removed" (first
one inch, minimum) runoff; however, in all cases, at least the first
0.5 inch of the permanently removed runoff should be infiltrated.
(4) This method is exempt from the requirements of §
395-16, Rate controls.
The following permit requirements may apply to certain regulated
earth disturbance activities, and must be met prior to the commencement
of regulated earth disturbance activities, as applicable:
A. All regulated earth disturbance activities subject to permit requirements
by DEP under regulations at 25 Pa. Code Chapter 102.
B. Work within natural drainageways subject to permit by DEP under 25 Pa. Code Chapter
105.
C. Any stormwater management facility that would be located in or adjacent to regulated surface waters of the commonwealth, including wetlands, subject to permit by DEP under 25 Pa. Code Chapter
105.
D. Any stormwater management facility that would be located on a state
highway right-of-way, or require access from a state highway, shall
be subject to approval by the Pennsylvania Department of Transportation
(PennDOT).
E. Culverts, bridges, storm sewers or any other facilities which must pass or convey flows from the tributary area and any facility which may constitute a dam subject to permit by DEP under 25 Pa. Code Chapter
105.