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.
Impervious cover.
(1)
Any proposed regulated activity, except those defined in § 220-5D(5) through (8) of this chapter, which would create 5,000 square feet or less of additional impervious cover is exempt from the drainage plan preparation provisions of this chapter, subject to the provisions noted below.
(a)
The date of the Township ordinance adoption of the original
Bushkill Creek, Fry's Run, Monocacy Creek, and Nancy Run Act
167 stormwater management ordinances (May 1992, February 1999, March
1989, and March 1989, respectively) shall be the site conditions starting
point from which to define tracts as "parent tracts." The starting
point conditions are established as predevelopment conditions, the
baseline upon which future subdivisions and respective impervious
area computations on these tracts shall be cumulatively considered;
(b)
If a parent tract has received a prior exemption of the provisions of this chapter, or there is no evidence of a prior stormwater management plan approval, and additional development is proposed (with at least 1,000 square feet of new impervious cover) such that all existing impervious cover installed on that tract since original ordinance adoption, as identified in § 220-35A(1)(a), plus the proposed impervious cover on the parent tract exceeds 5,000 square feet, a drainage plan shall be required. The drainage plan shall consider the proposed impervious cover as well as all existing impervious cover installed on that tract since original ordinance adoption, as identified in § 220-35A(1)(a), as new impervious cover;
(c)
For new development proposed on a lot created from a subdivided
parent tract, which had received a prior exemption, and which would
create greater than 5,000 square feet of impervious cover in the aggregate
on the parent tract, the current drainage plan shall control runoff
from only the impervious cover on the lot with the proposed new development.
If any impervious cover is proposed on any previously developed, prior
exempted lot, and the parent tract aggregate impervious cover exceeds
5,000 square feet, all impervious cover on that building lot since
original ordinance adoption shall meet the chapter provisions;
(d)
Refer to § 220-21S for requirements associated with parent tracts with existing drainage problems. For development taking place in stages, the entire development plan must be used in determining conformance with the criteria of this section of the chapter;
(e)
Additional impervious cover shall include, but not be limited
to, additional indoor living spaces, decks, patios, garages, driveways,
storage sheds and similar structures, and roof, parking or driveway
areas, and any new streets and sidewalks constructed as part of or
for the proposed regulated activity; and
(f)
Any additional areas proposed initially to be gravel, crushed
stone, porous pavement, etc., shall be assumed to be impervious for
the purposes of comparison to the exemption criteria of this chapter.
Any existing gravel, crushed stone or hard-packed soil areas on a
site shall be considered as pervious cover for the purpose of exemption
evaluation of this chapter.
(2)
If a drainage plan is required, the predevelopment and post-development
calculations should be based on actual cover conditions regardless
of any assumptions made for purposes of exemption evaluation of this
chapter.
B.
Prior drainage plan approval. Any regulated activity for which a drainage plan was previously prepared as part of a subdivision or land development proposal that received at least preliminary plan approval (the "approval") from the Township prior to the effective date of this chapter is exempt from the drainage plan preparation provisions of this chapter, except as cited in § 220-35C of this chapter, provided that the approved drainage plan included design of stormwater facilities to control runoff from the site currently proposed for regulated activities consistent with the chapter provisions in effect at the time of the approval, and the approval has not lapsed under the MPC. If significant revisions are made to the drainage plan after both the approval and the effective date of this chapter, preparation of a new drainage plan, subject to the provisions of this chapter, shall be required. Significant revisions would include a change in control methods or techniques, relocation or redesign of control measures, or changes necessary because soil or other conditions are not as stated on the original drainage plan.
C.
These exemptions shall not relieve the applicant from implementing
such measures as are necessary to protect health, safety, and property,
and to meet state water quality requirements. These measures include
adequate and safe conveyance of stormwater on the site and as it leaves
the site. These exemptions do not relieve the applicant from the responsibility
to secure permits or approvals for activities regulated by any other
applicable code, rule, act, or ordinance of the Township.
E.
Agricultural activity is exempt from the rate control and drainage
plan preparation requirements of this chapter, provided the activities
are performed according to the requirements of 25 Pa. Code Chapter
102.
F.
Timber harvesting activities are exempt from the rate control and
drainage plan preparation requirements of this chapter, provided the
activities are performed according to the requirements of 25 Pa. Code
Chapter 102.
G.
The Township may deny or revoke any exemption pursuant to this section
at any time for any project that the Township believes may pose a
threat to public health, safety, property, or the environment.
A.
All plans showing the proposed stormwater control system (including any storm sewer construction) shall be accompanied by a complete design signed, stamped, and certified by a Pennsylvania registered (professional) engineer and shall be submitted along with any required preliminary or final plan under Chapter 230, Subdivision and Land Development, of the Code of the Township of Bethlehem.
B.
When subdivisions or land developments are submitted to the Township
for approval in sections, a complete general stormwater control system
(including any storm sewer construction) design for the proposed subdivision
or land development shall be submitted with the preliminary plan.
The proposed design shall take into account the entire tract and the
watershed.
C.
All stormwater controls shall be designed to function adequately
after the completion of each phase of a subdivision or land development.
This may require the use of temporary structures, which shall be shown
on submitted development plans.
D.
The construction of stormwater controls in areas of future phases
of a development shall be required prior to construction of earlier
phases if the Township Engineer determines that is necessary to make
sure that the stormwater system will work after the completion of
each phase. This shall, for example, include the extension of the
main outfall line.
E.
A set of approved stormwater design plans shall be maintained on
file at the site during construction, as record drawings.
F.
Drainage structures that are located on PENNDOT rights-of-way shall
be found to be acceptable to PENNDOT and PENNDOT approval shall be
a condition of any final approval of the Township.
G.
Submission requirements.
(2)
In addition to the above-referenced requirements, when any activity that would result in the addition of greater than 5,000 square feet of impervious cover is specifically regulated by Article IV of this chapter. Drainage plans shall be submitted to the Lehigh Valley Planning Commission for review. Such drainage plans shall also contain the following:
(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 Northampton
County Soil Survey, as applicable, latest edition. Any hydric soils
present on the site should be identified as such;
[7]
Proposed changes to land surface and vegetative cover;
[8]
Proposed structures, roads, paved areas and buildings;
[9]
Final contours at intervals of two feet. In areas of steep slopes
(greater than 15%), five-foot contour intervals may be used;
[10]
Stormwater management district boundaries applicable
to the site;
[11]
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;
[12]
Clear identification of the location and nature
of permanent stormwater BMPs;
[13]
An adequate access easement around all stormwater
BMPs that would provide Township ingress to and egress from a public
right-of-way;
[14]
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; and
[15]
An overlay showing geologic types, boundaries,
and any special geologic features present on the site.
(c)
Stormwater management controls and BMPs.
[1]
All stormwater management controls must 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); and
[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 control device or method must be shown;
[3]
A chart describing the maximum allowable impervious cover per
lot based upon the stormwater management calculations;
[4]
All site testing data used to determine the feasibility of infiltration
on a site; and
[5]
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 VIII, 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 Township.
(e)
Environmental resources site design assessment.
[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; and
[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 maximum allowable impervious coverage on a per-lot basis
as considered in the stormwater management design for the site shall
be identified on a BMP operations and management plan and also on
the subdivision and land development plan to be recorded. These record
plans shall identify each property owner's responsibility and
basis for paying municipal stormwater fees in accordance with the
Bethlehem Township Stormwater Fee Ordinance, latest edition.
A.
(1)
The drainage plan shall be submitted by the developer to the Township
as part of the preliminary plan submission for the subdivision or
land development.
(2)
Five copies of the drainage plan shall be submitted.
(3)
Distribution of the drainage plan will be as follows:
(4)
Drainage plans involving more than 10,000 square feet of additional
impervious cover shall be submitted by the developer (possibly through
the Township) to the Lehigh Valley Planning Commission as part of
the preliminary plan submission. The Lehigh Valley Planning Commission
will conduct an advisory review of the drainage plan for consistency
with the Bushkill Watershed, Fry's Run Watershed, Monocacy Creek
Watershed, or the Nancy Run Watershed stormwater management ordinance.
The Lehigh Valley Planning Commission will not review details of the
erosion and sedimentation plan or the BMP operations and maintenance
plan:
(a)
Two copies of the drainage plan shall be submitted; and
(b)
The Lehigh Valley Planning Commission will provide written comments
to the developer and the Township, within a time frame consistent
with established procedures under the Municipalities Planning Code,
as to whether the drainage plan has been found to be consistent with
the stormwater management ordinance.
C.
(1)
The drainage plan shall be submitted by the developer to the Lehigh
Valley Planning Commission for coordination with the DEP permit application
process under Chapter 105 (Dam Safety and Waterway Management) or
Chapter 106 (Floodplain Management) of DEP's rules and regulations;
and
(2)
One copy of the drainage plan shall be submitted.
A.
The Township Engineer shall review the drainage plan, including the
BMP operations and maintenance plan, for consistency with the adopted
stormwater management plan as embodied by this chapter and with any
permits issued by DEP.
C.
The Township shall notify the applicant in writing whether the drainage
plan, including the BMP operations and maintenance plan, is approved,
consistent with time frames as established by the current Pennsylvania
Municipalities Planning Code.
D.
The Township may require an "as-built survey" of all stormwater BMPs
including a survey of any detention/retention basin prior to installation
of liner and/or topsoil as applicable, as well as basin stage storage
calculations, and an explanation of any discrepancies with the drainage
plan.
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.
A.
The Township Board of Commissioners, after receiving the recommendation
from the Planning Commission, may hear requests for waivers where
it is alleged that the provisions of this chapter inflict unnecessary
hardship upon the applicant. The waiver request shall be in writing
and accompanied by the requisite fee based upon a fee schedule adopted
by the Township Board of Commissioners. A copy of the waiver request
shall be provided to each of the following: Township Manager, Township
Zoning Hearing Board, Township Engineer, Director of Community Development,
Township Solicitor and Lehigh Valley Planning Commission. The request
shall fully document the nature of the alleged hardship.
B.
The Township may grant a waiver, provided that all of the following
findings are made in a given case:
(1)
That there are unique physical circumstances or conditions, including
irregularity of lot size or shape, or exceptional topographical or
other physical conditions peculiar to the particular property, and
that the unnecessary hardship is due to such conditions, and not the
circumstances or conditions generally created by the provisions of
this chapter in the stormwater management district in which the property
is located;
(2)
That because of such physical circumstances or conditions there is
no possibility that the property can be developed in strict conformity
with the provisions of this chapter, including the no harm provision,
and that the authorization of a waiver is therefore necessary to enable
the reasonable use of the property;
(3)
That such unnecessary hardship has not been created by the applicant;
(4)
That the waiver, if authorized, will represent the minimum waiver
that will afford relief and will represent the least modification
possible of the regulation in issue; and
(5)
That financial hardship is not the criteria for granting a hardship
waiver.
C.
In granting any waiver, the Township Board of Commissioners or Zoning
Hearing Board may attach such reasonable conditions and safeguards
as it may deem necessary to implement the purposes of this chapter.
Such conditions may include, but not be limited to (if recommended
by the Township Engineer), a requirement that comparable detention
be located by the applicant on lands other than those on which the
waiver has been requested, to assure that the overall detention capability
of a given subarea is not diminished and that the overall rate of
runoff is not increased as a result of the waiver. If a hardship waiver
is granted, the applicant must still manage the quantity, velocity
quality, and direction of resulting storm runoff as is reasonably
necessary to prevent injury to health, safety, or other property:
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[1]) 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
A.
For areas not covered by a release rate map from an approved Act
167 stormwater management plan: Post-development discharge rates shall
not exceed the predevelopment discharge rates for the two-, ten-,
twenty-five-, fifty-, and 100-year, twenty-four-hour storm events.
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 predevelopment analysis for two-, ten-, twenty-five-, fifty-,
and 100-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.
B.
For areas covered by a release rate map from an approved Act 167
stormwater management plan: For the two-, ten-, twenty-five-, fifty-,
and 100-year, twenty-four-hour storm events, the post-development
peak discharge rates will follow the applicable approved release rate
maps. For any areas not shown on the release rate maps, the post-development
discharge rates shall not exceed the predevelopment discharge rates.
A.
In order to protect and improve water quality, a riparian buffer
easement shall be created and recorded as of any subdivision or land
development that encompasses a riparian buffer.
B.
Except as required by Chapter 102, the riparian buffer easement shall
be measured to be the greater of the 100-year floodplain or a minimum
of 35 feet from the top of the streambank (on each side).
C.
Minimum management requirements for riparian buffers.
(1)
Existing native vegetation shall be protected and maintained within
the riparian buffer easement; and
(2)
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.
D.
The riparian buffer easement shall be enforceable by the Township
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 Township
Zoning Ordinance.[1]
E.
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.
G.
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.
