[Ord. 2012-144, 8/9/2012, § 301]
1.
For all regulated activities, unless preparation of an SWM site plan is specifically exempted in § 20-302:
2.
All SWM site plans for regulated activities shall include such measures
as necessary to:
A.
Protect health, safety, and property.
B.
Meet the water quality goals of this chapter, as stated in § 20-103, by including measures that:
(1)
Minimize disturbance to floodplains, wetlands, wooded areas,
and existing vegetation.
(2)
Maintain or extend riparian buffers.
(3)
Avoid erosive flow conditions in natural flow pathways.
(4)
Minimize thermal impacts to waters of the commonwealth.
(5)
Disconnect impervious surfaces by directing runoff to pervious
areas.
(6)
Minimize soil disturbance and compaction.
C.
Incorporate the techniques for low impact development practices described
in the Pennsylvania Stormwater Best Management Practices Manual (BMP
Manual) which is hereby incorporated by reference.
3.
Stormwater flows onto adjacent property shall not be created, increased,
decreased, relocated, or otherwise altered without the written notification
of the adjacent property owner(s) by the developer. Copies of all
such notifications shall be included in the SWM site plan submission.
4.
For all regulated activities where erosion and sediment control is
required in accordance with Title 25 of the Pennsylvania Code and
the Clean Streams Law, the SWM site plan shall include the required
erosion and sedimentation control measures. Necessary E&S BMPs
shall be designed in accordance with the Erosion and Sediment Pollution
Control Program Manual (E&S Manual) 2, No. 363-2134-008 (April
15, 2000), as amended and updated which is hereby incorporated by
reference. Approval of the SWM site plan by Cumberland Township shall
be conditioned on the applicant obtaining erosion and sedimentation
control approval from the appropriate agency(ies), when applicable.
5.
For all regulated activities where NPDES permitting is required in
accordance with the Clean Water Act (33 U.S.C. § 1251 et
seq. (1972), as amended), the SWM site plan shall include the information
required in the applicant's NPDES permit application. Approval
of the SWM site plan by Cumberland Township shall be conditioned on
the applicant obtaining NPDES permit approval from the appropriate
agency(ies), when applicable.
7.
Special Management Areas. SWM site plans involving regulated activities
within special management areas shall be prepared in a manner consistent
with the guidance provided in Chapter 7 of the BMP Manual. The SWM
site plan submission shall include design details for SWM BMPs within
said special management area.
8.
A SWM site plan may propose that stormwater related to the proposed
regulated activities be accommodated by existing stormwater management
facilities on adjoining or nearby properties provided that the SWM
site plan documents the following:
A.
The use of the stormwater management facilities located on said adjoining
or nearby property is approved in writing by the owner of the property.
B.
The stormwater management facilities located on said adjoining or
nearby property are designed in a manner that can accommodate the
stormwater management needs of the regulated activity in a manner
consistent with all requirements of this chapter. The SWM site plan
shall include all documentation necessary for Cumberland Township
to confirm such compliance.
9.
The design storm volumes to be used in the analysis of peak rates
of discharge shall be obtained from the Precipitation-Frequency Atlas
of the United States, Atlas 14, Volume 2, Version 3.0, as amended
and updated, U.S. Department of Commerce, National Oceanic and Atmospheric
Administration (NOAA), National Weather Service, Hydrometeorological
Design Studies Center, Silver Spring, Maryland. NOAA's Atlas
14 can be accessed at: http://hdsc.nws.noaa.gov/hdsc/pfds/.
10.
SWM site plans, once approved by Cumberland Township, shall remain
on site throughout the duration of the regulated activity and be available
for review as may be necessary by representatives of Cumberland Township.
11.
The design of all facilities over karst shall include an evaluation
of measures to minimize adverse effects.
12.
Cumberland Township may, after consultation with DEP, approve measures
for meeting the state water quality requirements other than those
in this chapter, provided that they meet the minimum requirements
of, and do not conflict with, state law including, but not limited
to, the Clean Streams Law. The Township shall maintain a record of
consultations with DEP pursuant to this subsection.
[Ord. 2012-144, 8/9/2012, § 302]
1.
A property owner or developer of any regulated activity that meets
the following exemption criteria is, upon approval from Cumberland
Township, exempt from the formal SWM plan submission requirements
of this chapter as specified herein. However, the property owner or
developer shall be subject to all other requirements of this chapter
other than the formal SWM plan submission requirements for which an
exemption or exemptions have been authorized. The criteria for exemption
in this section apply to the total development proposed, including
instances in which the development is proposed to take place in phases.
The date of enactment of this chapter shall be the starting point
from which future development and the respective exemption criteria
shall be cumulatively considered and regulated.
A.
Regulated activities that involve equal to or less than 1,000 square
feet of impervious surface may be exempted from the peak rate control,
volume control and the SWM site plan preparation and submission requirements
of this chapter. The applicant shall complete and submit Worksheet
A and a sketch plan as described in the Stormwater Management Design
Assistance Manual. Activities that involve the diversion or piping
of any natural man-made watercourse including the relocation of such
facility or watercourse are not exempt from submission of a stormwater
management plan.
B.
Regulated activities that involve greater than 1,000 square feet
and equal to or less than 10,000 square feet of impervious area, and
where all the proposed impervious area can be entirely disconnected,
may be exempted from the peak rate control, volume control, and the
SWM site plan preparation and submission requirements of this chapter.
The applicant in this instance shall complete and submit the Stormwater
Management Worksheets (A&B) from the Stormwater Management Design
Assistance Manual, a Minor Stormwater Site Plan, and an executed Owner's
Acknowledgement.
C.
Regulated activities that involve greater than 1,000 square feet
and equal to or less than 5,000 square feet of impervious area may
be exempted from the peak rate control and volume control preparation
and submission requirements of this chapter. The applicant shall complete
and submit the Stormwater Management Worksheets (A&B) from the
Stormwater Management Design Assistance Manual, a Minor Stormwater
Site Plan showing BMP facilities, an executed Owner's Acknowledgement
or Operation and Maintenance Agreement (as required).
D.
Agricultural activities shall be exempt from the rate control, volume control and SWM site plan preparation and submission requirements of this chapter provided the agricultural activities are performed in accordance with the requirements of 25 Pa.Code [Chapter] 102. Further, such activities shall not be subject to the exemption approval process of Subsection 2 of this section.
E.
Forest management and timber operations are exempted from the rate
control, volume control and SWM site plan preparation and submission
requirements of this chapter provided the forest management and timber
operations are performed in accordance with the requirements of 25
Pa.Code [Chapter] 102 which shall include preparation of an erosion
control plan for submission to the Adams County Conservation District.
F.
Regulated activities involving domestic gardening for single-family consumption shall be exempted from volume control, rate control, and SWM site plan preparation and submission requirements of this chapter, and shall not be subject to the exemption approval process of Subsection 2 of this section.
G.
In kind repair, in kind replacement, and maintenance of existing surfaces, and structures shall be exempted from volume control, rate control, and SWM site plan preparation and submission requirements of this chapter, and shall not be subject to the exemption approval process of Subsection 2 of this section.
2.
Authorization of Exemptions. The Building Permit Officer shall determine,
in accordance with the following requirements and process, whether
a proposed regulated activity may be exempted from any of the requirements
of this chapter.
A.
The property owner or developer proposing the regulated activity
shall submit materials as required by the Design Assistance Manual.
B.
Upon receipt of said materials, the Building Permit Officer shall
either approve or deny the exemption request. If the exemption request
is denied, the Building Permit Officer or its designee shall direct
the property owner or developer to submit the information required
to demonstrate that the proposed regulated activity complies with
the requirements of this chapter or meets the exemption criteria.
C.
Exemption request approval shall be at the discretion of the Building
Permit Officer, and shall be subject to the following:
(1)
The Building Permit Officer may deny any exemption request or
suspend or revoke any approved exemption request at any time for any
project where Cumberland Township, the Building Permit Officer, or
the Township Engineer believes that the proposed regulated activity
poses a threat to public health, safety, property, or the environment.
(2)
Approval of an exemption request does not relieve the property
owner or developer from other applicable requirements of this chapter
or of other Cumberland Township ordinance or regulations.
(3)
Cumberland Township reserves the right to deny an exemption
request if a pre-existing drainage problem is known or has been identified
or if a drainage problem is expected to exist downstream from the
proposed regulated activity.
[Ord. 2012-144, 8/9/2012, § 303]
1.
Impervious Area.
A.
The measurement of impervious areas shall include all of the impervious
areas in the total proposed development, even if development is to
take place in phases.
B.
For development taking place in phases, the total proposed impervious
area within the SWM site plan must be used in determining conformance
with this chapter.
C.
For projects that add impervious area to a parcel, the total impervious area on the parcel is subject to the requirements of this chapter; except that the volume controls in § 20-304 and the peak rate controls of § 20-305 do not need to be retrofitted to existing impervious areas that are not being altered by the proposed regulated activity.
2.
Normally dry, open-top storage facilities, designed as such, shall
completely drain both the volume control and rate control capacities
over a period of time not less than 24 hours and not more than 72
hours from the end of the design storm. However, any designed infiltration
volume at such facilities is exempt from the minimum twenty-four-hour
standard, i.e., may infiltrate in a shorter period of time, so long
as none of the stormwater intended for infiltration is discharged
into the surface waters of the commonwealth.
3.
Infiltration BMPs shall be spread out, made as shallow as practicable,
and located to maximize use of natural on-site infiltration features
while still meeting the other requirements of this chapter.
[Ord. 2012-144, 8/9/2012, § 304]
1.
The low impact development practices provided in the BMP Manual shall
be utilized for all regulated activities. Water volume controls shall
be implemented using the Design Storm Method (CG 1) in Subsection
1A or the Simplified Method (CG 2) in Subsection 1B. For regulated
activity involving less than one acre of impervious coverage that
does not require hydrologic routing to design the stormwater facilities,
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/or other
factors. The Design Storm Method in Subsection 1A, shall be used for
all regulated activity involving greater than one acre of impervious
coverage.
A.
The Design Storm Method (CG-1 in the BMP Manual) may be used for
any size of regulated activity. This method requires detailed modeling
to achieve the following standards:
(1)
The post-development total runoff volume shall not increase
for all storms equal to or less than the two-year twenty-four-hour
duration precipitation.
(2)
For modeling purposes:
(a)
Existing (pre-development), non-forested, pervious areas must
be considered meadow.
(b)
Twenty percent of existing impervious area, when present, shall
be considered meadow in the model for existing conditions. The Township
may require a greater percentage be considered as meadow where the
Township has identified a pre-existing drainage problem for a site
in which stormwater management was not previously incorporated.
B.
The Simplified Method (CG-2 in the BMP Manual) is independent of
site conditions and may be used for projects involving regulated activities
proposing equal to or less than one acre of impervious coverage and
that do not require design of stormwater storage facilities. When
the Simplified Method is used to address stormwater management needs
of new impervious surfaces, the following design standards shall be
achieved:
(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 and shall not be
released into the surface waters of the commonwealth. Removal options
for the first one inch of runoff include, but are not necessarily
limited to, reuse and infiltration.
(3)
Infiltration facilities shall be designed to accommodate infiltration
of as much of the permanently removed runoff as site conditions will
allow. If the soils within the project area do not allow for infiltration
of the entire first one inch of runoff from new impervious surfaces,
other forms of runoff volume control shall be used to achieve the
required removal volume. Such measures may include, but are not limited
to, vegetated roofs, bioretention, and capture-and-reuse systems.
In addition, the infiltration alternative authorized in paragraph
.C may be employed.
C.
Infiltration Alternative. Where infiltration is not possible due
to soil characteristics or is not desirable given other characteristics,
water quality control may be proposed as an alternative to strict
adherence to the volume control standards of this section of this
chapter. Where water quality control is proposed, the following standards
shall be achieved:
(1)
At a minimum, the following documentation shall be provided
to justify the proposal to reduce the infiltration requirements:
(a)
Description of and justification for field infiltration/permeability
testing with respect to the type of test and test locations.
(b)
An interpretive narrative describing existing soils of the site
and their structure as these relate to the interaction between soils
and water characteristics of the site. In addition to providing soil
and soil profile descriptions, this narrative shall identify depth
to seasonal water tables and depth to bedrock and provide a description
of all subsurface elements (restrictive layers, geology, etc.) that
influence the direction and rate of subsurface water movement.
(c)
A qualitative assessment of the site's contribution to
annual aquifer recharge shall be made, along with the identification
of any restrictions or limitations associated with the use of designed
infiltration facilities.
(d)
The provided documentation must be signed and sealed by a professional
engineer or geologist.
(2)
Water quality BMPs shall be implemented on all permanent stormwater
discharges from the proposed project site to achieve pollutant removal
efficiencies in accordance with the Table 20-304.1.
|
Table 20-304.1
| |||
|---|---|---|---|
|
Required Pollutant Removal Efficiencies for Infiltration
Alternatives
| |||
|
Pollutant Load
|
Units
|
Required Removal Efficiency
(%)
| |
|
Total Suspended Solids (TSS)
|
Pounds
|
85%
| |
|
Total Phosphorus (TP)
|
Pounds
|
85%
| |
|
Total Nitrate (NO3)
|
Pounds
|
50%
| |
(3)
Design guidance from the most current version of the Pennsylvania
Stormwater Best Management Practices Manual, or equivalent resource
as pre-coordinated with Cumberland Township, shall be consulted when
choosing design criteria for water quality BMPs.
[Ord. 2012-144, 8/9/2012, § 305]
1.
Post-development discharge rates shall not exceed the pre-development
discharge rates for the one-, two-, five-, ten-, twenty-five-, fifty-,
and one-hundred-year twenty-four-hour storms. If it is shown that
the peak rates of discharge indicated by the post-development analysis
are less than or equal to the peak rates of discharge indicated by
the pre-development analysis for one-, two-, five-, ten-, twenty-five-,
fifty-, and one-hundred-year, twenty-four-hour storms, then the requirements
of this section have been met. Otherwise, the applicant shall provide
additional controls as necessary to satisfy the peak rate of discharge
requirement.
2.
For computation of pre-development peak discharge rates, 20% of existing
impervious areas, when present, shall be considered meadow.
[Ord. 2012-144, 8/9/2012, § 306]
Where an applicant proposes to utilize riparian buffers as the
means to meet the requirements of this chapter, said riparian buffers
shall be established and/or maintained in accordance with the BMP
Manual or the publication Riparian Forest Buffer Guidance, published
November, 2010, by the Pennsylvania Department of Environmental Protection,
and as may be amended or updated.
[Ord. 2012-144, 8/9/2012, § 307]
1.
Any drain or conveyance, whether on the surface or subsurface, that
allows any non-stormwater discharge including sewage, process wastewater,
and wash water to enter the waters of the commonwealth is prohibited.
2.
No person shall allow, or cause to allow, discharges into surface waters of the commonwealth which are not composed entirely of stormwater, except (A) as provided in Subsection 3 below, and (B) discharges allowed under a state or federal permit.
3.
The following discharges are authorized unless they are determined
to be significant contributors to pollution to the waters of the commonwealth:
A.
Discharges from firefighting activities.
B.
Potable water sources including water line flushing.
C.
Air conditioning condensate.
D.
Springs.
E.
Water from crawl space pumps.
F.
Pavement wash waters where spills or leaks of toxic or hazardous
materials have not occurred (unless all spill material has been removed)
and where detergents are not used.
G.
Diverted stream flows.
H.
Flows from riparian habitats and wetlands.
I.
Uncontaminated water from foundations or from footing drains.
J.
Lawn watering.
K.
De-chlorinated swimming pool discharges.
L.
Uncontaminated groundwater.
M.
Water from individual residential car washing.
N.
Routine external building wash-down (which does not use detergents
or other compounds).
O.
Water discharged in well testing for potable water supplies.
[Ord. 2012-144, 8/9/2012, § 308]
Roof drains, sump pumps, and footer drains should discharge
to infiltration or vegetative BMPs and, to the maximum extent practicable,
satisfy the criteria for DIAs. Discharges of each should be conveyed
in such a manner as to not cause water problems for adjoining property
owners.
[Ord. 2012-144, 8/9/2012, § 309]
No person shall modify, remove, fill, landscape, or alter any
SWM BMPs, facilities, areas, or structures in a manner, without the
written approval of Cumberland Township, with the exception of necessary
maintenance activities such as mowing.
