[Ord. 2010-3, 12/16/2010, § 1]
1.
For all regulated activities, unless specifically exempted in § 26-117:
A.
Preparation and implementation of an approved SWM site plan is required.
B.
No regulated activities shall commence until Hummelstown Borough
issues written approval of a SWM site plan, which demonstrates compliance
with the requirements of this Part.
D.
The SWM site plan approved by Hummelstown Borough, shall be on-site
throughout the duration of the regulated activities.
2.
For all regulated earth disturbance activities, erosion and sediment
control BMPs shall be designed, implemented, operated, and maintained
during the regulated earth disturbance activities (e.g., during construction)
to meet the purposes and requirements of this Part and to meet all
requirements under Title 25 of the Pennsylvania Code (including, but
not limited to, Chapter 102, Erosion and Sediment Control) and the
Clean Streams Law. Various BMPs and their design standards are listed
in the Erosion and Sediment Pollution Control Program Manual (E&S
manual), No. 363-2134-008 (April 15, 2000), as amended and updated.
3.
For all regulated activities, stormwater BMPs shall be designed,
installed, implemented, operated, and maintained to meet the purposes
and requirements of this Part and to meet all requirements under Title
25 of the Pennsylvania Code and the Clean Streams Law, conform to
the state water quality requirements, meet all requirements under
the Storm Water Management Act and any more stringent requirements
as determined by Hummelstown Borough.
4.
Hummelstown Borough may, after consultation with PADEP and/or DCCD,
approve measures for meeting the state water quality requirements
other than those in this Part, provided that they meet the minimum
requirements of, and do not conflict with, state law including, but
not limited to, the Clean Streams Law.
5.
All regulated activities shall include, to the maximum extent practicable,
measures to:
A.
Protect health, safety, and property.
B.
Meet the water quality goals of this Part by implementing measures
to:
(1)
Minimize disturbance to floodplains, wetlands, natural slopes,
existing native vegetation and woodlands.
(2)
Create, maintain, or extend riparian buffers and protect existing
forested buffers.
(3)
Provide trees and woodlands adjacent to impervious areas whenever
feasible.
(4)
Minimize the creation of impervious surfaces and the degradation
of waters of the Commonwealth and promote groundwater recharge.
(5)
Protect natural systems and processes (drainageways, vegetation,
soils, and sensitive areas) and maintain, as much as possible, the
natural hydrologic regime.
(6)
Incorporate natural site elements (wetlands, stream corridors,
mature forests) as design elements.
(7)
Avoid erosive flow conditions in natural flow pathways.
(8)
Minimize soil disturbance and soil compaction.
(9)
Minimize thermal impacts to waters of the Commonwealth.
(10)
Disconnect impervious surfaces by directing runoff to pervious
areas wherever possible, and decentralize and manage stormwater at
its source.
C.
Incorporate methods described in the Pennsylvania Stormwater Best
Management Practices Manual (BMP Manual). Applicants are encouraged
to incorporate the techniques for low-impact development practices
described in the BMP Manual to reduce the costs of complying with
the requirements of this Part and the state water quality requirements.
[Amended Ord. No. 2022-4, 10/13/2022]
6.
Impervious Areas.
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 stages.
B.
For development taking place in stages, the entire development plan
must be used in determining conformance with this Part.
C.
For projects that add impervious area to a developed parcel, the
new impervious area is subject to the requirements of this Part; and
any existing impervious area that is within the new proposed limit
of disturbance is also subject to the requirements of this Part.
7.
If diffused flow is proposed to be concentrated and discharged onto
adjacent property, the applicant must document that adequate downstream
conveyance facilities exist to safely transport the concentrated discharge,
or otherwise prove that no erosion, sedimentation, flooding, or other
harm will result from the concentrated discharge.
A.
Applicant must provide an executed easement for newly concentrated
flow across adjacent properties.
8.
Stormwater drainage systems shall be provided in order to permit
unimpeded flow along natural watercourses, except as modified by stormwater
management facilities or open channels consistent with this Part.
9.
Where watercourses traverse a development site, drainage easements
(with a minimum width of 20 feet) shall be provided conforming to
the line of such watercourses. The terms of the easement shall prohibit
excavation, the placing of fill or structures, and any alterations
that may adversely affect the flow of stormwater within any portion
of the easement. Also, maintenance, including mowing of vegetation
within the easement may be required, except as approved by the appropriate
governing authority.
10.
When it can be shown that, due to topographic conditions, natural
drainageways on the site cannot adequately provide for drainage, open
channels may be constructed conforming substantially to the line and
grade of such natural drainageways. Work within natural drainage ways
shall be subject to approval by PADEP under regulations at 25 Pa.Code,
Chapter 105, through the joint permit application process, or, where
deemed appropriate by PADEP, through the general permit process.
11.
Any stormwater management facilities or any facilities that constitute
water obstructions (e.g., culverts, bridges, outfalls, or stream enclosures,
etc.) that are regulated by this Part, that will be located in or
adjacent to waters of the Commonwealth (including wetlands), shall
be subject to approval by PADEP under regulations at 25 Pa.Code, Chapter
105, through the joint permit application process, or, where deemed
appropriate by PADEP, the general permit process. When there is a
question whether wetlands may be involved, it is the responsibility
of the applicant or his agent to show that the land in question cannot
be classified as wetlands; otherwise, approval to work in the area
must be obtained from PADEP.
12.
Should any stormwater management facility require a dam safety permit
under PADEP Chapter 105, the facility shall be designed in accordance
with Chapter 105 and meet the regulations of Chapter 105 concerning
dam safety which may be required to pass storms larger than one-hundred-year
event.
13.
Any stormwater management facilities regulated by this Part that
will be located on, or discharged onto state highway rights-of-ways
shall be subject to approval by the Pennsylvania Department of Transportation
(PennDOT).
14.
When stormwater management facilities are proposed within 1,000 feet
of a downstream municipality, the stormwater analysis shall be submitted
to the downstream municipal's engineer for review and comment.
15.
Minimization of impervious surfaces and infiltration of runoff through
seepage beds, infiltration trenches, etc., are encouraged, where soil
conditions and geology permit, to reduce the size or eliminate the
need for detention facilities.
16.
Infiltration BMPs should be dispersed throughout the site, made as
shallow as practicable, and located to maximize use of natural on-site
infiltration features while still meeting the other requirements of
this Part.
17.
The design of facilities over karst shall include an evaluation and
implementation of measures to minimize adverse effects.
18.
Roof drains shall not be connected to streets, sanitary or storm
sewers, or roadside ditches in order to promote overland flow and
infiltration/percolation of stormwater where it is advantageous to
do so. When it is more advantageous to connect directly to streets
or storm sewers, then Hummelstown Borough shall permit it on a case-by-case
basis.
[Ord. 2010-3, 12/16/2010, § 1]
2.
Hummelstown Borough, at its discretion, may require an applicant
to demonstrate that the following BMPs are being utilized to the maximum
extent practicable to receive consideration for the exemptions:
A.
Limit disturbance of floodplains, wetlands, natural slopes over 30%,
existing native vegetation, and other sensitive and special value
features.
B.
Maintain riparian and forested buffers.
C.
Limit grading and maintain non-erosive flow conditions in natural
flow paths.
D.
Maintain existing tree canopies near impervious areas.
E.
Minimize soil disturbance and reclaim disturbed areas with topsoil
and vegetation.
F.
Direct runoff to pervious areas.
3.
Hummelstown Borough, at its discretion, may require an applicant
to demonstrate that the proposed development/additional impervious
area will not adversely impact the following:
4.
An applicant proposing regulated activities, after demonstrating compliance with Subsections 1, 2, and 3, may be exempted from various requirements of this Part according to the following table:
|
New Impervious Area
[Since the Date of Adoption of this Part]
(square footage)
|
Applicant Must Submit to Hummelstown Borough
| |
|---|---|---|
|
0 to 1,000
|
—
| |
|
1,000 to 5,000
|
Volume Controls and SWM Site Plan and Report
| |
|
>5,000
|
Rate Controls, Volume Controls, SWM Site Plan and Report and
Record Drawings
|
5.
The purpose of this section is to ensure consistency of stormwater
management planning between local ordinances and NPDES permitting
(when required) and to ensure that the applicant has a single and
clear set of stormwater management standards to which the applicant
is subject. Hummelstown Borough may accept alternative stormwater
management controls provided that:
A.
The applicant, in consultation with Hummelstown Borough, PADEP and/or
DCCD, states that meeting the requirements of the volume controls
or rate controls of this Part is not possible or creates an undue
hardship.
B.
The alternative stormwater management controls, proposed by the applicant,
are documented to be acceptable to Hummelstown Borough, PADEP and/or
DCCD for NPDES requirements pertaining to post construction stormwater
management requirements.
6.
Forest management and timber operations are exempt from rate and
volume control requirements and SWM site plan preparation requirement
of this Part provided the activities are performed according to the
requirements of 25 Pa.Code, Chapter 102. It should be noted that temporary
roadways are not exempt.
7.
Agricultural activities are exempt from the requirements of this
Part provided the activities are performed according to the requirements
of 25 Pa.Code, Chapter 102.
8.
Linear roadway improvement projects that create additional impervious
area are not exempt from the requirements of this Part. However, alternative
stormwater management strategies may be applied at the joint approval
of Hummelstown Borough and the Dauphin County Conservation District
(if an NPDES permit is required) when site limitations (such as limited
right-of-way) and constraints (as shown and provided by the applicant),
preclude the ability of the applicant to meet the enforcement of the
stormwater management standards in this Part. All strategies must
be consistent with PADEP's regulations, including NPDES requirements.
9.
Hummelstown Borough may, after an applicant has demonstrated compliance with Subsections 1, 2, and 3, grant a modification of the requirements of one or more provisions of this Part if the literal enforcement will exact undue hardship because of peculiar conditions pertaining to the land in question, provided that such modification will not be contrary to the public interest and that the purpose and intent of this Part is observed.
A.
All requests for a modification shall be in writing and shall state
in full the grounds and facts of unreasonableness or hardship on which
the request is based, the provision or provisions of the ordinance
involved, and the minimum modification necessary.
10.
Hummelstown
Borough 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.
[Added Ord. No. 2022-4, 10/13/2022]
[Ord. 2010-3, 12/16/2010, § 1]
1.
The low impact development practices provided in the BMP manual and
in Appendix B of this Part shall be utilized for all regulated activities
to the maximum extent practicable.
2.
Stormwater runoff volume controls shall be implemented using the
design storm method or the simplified method. For regulated activities
equal to or less than one acre, this Part establishes no preference
for either method; therefore, the applicant may select either method
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 sized regulated activity. This method requires detailed modeling
based on site conditions.
(1)
Do not increase the post-development total runoff volume when
compared to the pre-development total runoff volume for the two-year/twenty-four-hour
storm event.
(2)
For hydrologic modeling purposes:
(a)
Existing non-forested pervious areas must be considered meadow
(good condition) for pre-development hydrologic calculations.
(b)
Twenty percent of existing impervious area, when present on
the proposed project site, and contained within the new proposed limit
of disturbance, shall be considered meadow (good condition) for pre-development
hydrologic calculations for re-development.
B.
The simplified method (CG-2 in the BMP manual) 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. For new 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 surface waters of the 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 runoff;
however, in all cases at least the first 0.5 inch of the permanently
removed runoff should be infiltrated.
3.
All applicable worksheets from Chapter 8 of the BMP manual must be used when establishing volume controls.
4.
Actual field infiltration tests at the location of the proposed elevation
of the stormwater BMPs are required when 5,000 square feet or greater
of new impervious surface is added. Infiltration tests shall be conducted
in accordance with BMP manual. Hummelstown Borough shall be notified
24 hours prior to infiltration tests being conducted as to provide
an opportunity for Hummelstown Borough to witness the tests.
[Ord. 2010-3, 12/16/2010, § 1]
For all lands contained within Hummelstown Borough, the post-development
peak discharge rates shall not exceed the predevelopment peak discharge
rates for the one-, two-, ten-, twenty-five-, fifty-, and one-hundred-year
storms.
[Added by Ord. No. 2022-4, 10/13/2022]
1.
In order to protect and improve water quality, a riparian buffer
easement shall be created and recorded as part of any subdivision
or land development that encompasses a riparian buffer.
2.
Except as required by § 26-102, the riparian buffer easement shall be measured to be the greater of the limit of the 100-year floodplain or a minimum of 35 feet from the top of the streambank (on each side).
3.
Minimum Management Requirements for Riparian Buffers.
A.
Existing native vegetation shall be protected and maintained within
the riparian buffer easement.
B.
Whenever practicable invasive vegetation shall be actively removed
and the riparian buffer easement shall be planted with native trees,
shrubs and other vegetation to create a diverse native plant community
appropriate to the intended ecological context of the site.
4.
The riparian buffer easement shall be enforceable by the municipality
and shall be recorded in the appropriate County Recorder of Deeds
Office so that it shall run with the land and shall limit the use
of the property located therein. The easement shall allow for the
continued private ownership and shall count toward the minimum lot
area required by zoning, unless otherwise specified in the municipal
Zoning Ordinance.[1]
5.
Any permitted use within the riparian buffer easement shall be conducted
in a manner that will maintain the extent of the existing 100-year
floodplain, improve or maintain the stream stability, and preserve
and protect the ecological function of the floodplain.
7.
Septic drainfields and sewage disposal systems shall not be permitted
within the riparian buffer easement and shall comply with setback
requirements established under 25 Pa. Code Chapter 73.
