For purposes of stormwater management, the Township is located
in the Turtle Creek Watershed, which includes the Stormwater Management
Performance Districts shown on the Westmoreland County Integrated
Water Resources Plan interactive watershed resource map, which is
hereby adopted as a portion of the chapter. The stormwater release
rates for real property located within the Township shall be as set
forth on the Performance District Maps. For areas not covered by a
stormwater performance district, the release rate shall be 80%[1] of the pre-development peak flow as set by the municipality.
For more information, refer to www.westmorelandstormwater.org and
the Westmoreland County Conservation District's interactive watershed
resource map.
[1]
Editor's Note: In areas not covered by a Stormwater Performance
District, an 80% release rate or less is recommended as a standard.
This is to apply a "Factor of Safety" to stormwater calculations;
to account for the many variables in site design and stormwater management;
and to avoid a land development project inadvertently increasing runoff
and causing harm downstream.
A.
Preparation and implementation of a stormwater management site plan
is required for all regulated activities, unless preparation of a
SWM site plan is specifically exempted.
B.
Projects that propose greater than one acre of earth disturbance
are subject to NPDES permit requirements and will require a Stormwater
Management Plan.
C.
No regulated activities, unless exempted hereafter or herein, shall
commence until the Township issues written approval of an SWM Site
Plan which demonstrates compliance with the requirements of this chapter.
D.
Regulated development activities shall be as follows:
Regulated Development Activity Table[1]
| |||
---|---|---|---|
SWM Plan Requirement
|
New Impervious Area for New and Redevelopment
|
Disturbed Area*
|
Next Steps
|
Exempt
|
Less than 1,000 square feet
|
AND less than 1 acre
|
Comply with exemption section of this chapter
|
Waiver/modification/demonstrated equivalency
|
Less than 1/2 acre, subject to municipal approval
|
AND less than 1 acre
|
Comply with waiver/modification/demonstrated equivalency section
of this chapter
|
Small project (per definition), refer to Appendix C[2]
|
1,000 square feet to 3,000 square feet
|
OR 3,000 square feet to 5,000 square feet
|
Submit Small Project Site Plan complete with all attachments
|
Stormwater Management Plan meeting the chapter requirements
|
Greater than 3,000 square feet AND, if exempt, waiver/modification/demonstrated
equivalence and small project criteria are not met
|
OR greater than 5,000 square feet
|
Consult a qualified professional
|
[1]
Editor's Note: This table is only applicable for projects
with earth disturbance less than one acre and that have not had cumulative
impacts, within five years preceding the permit application date,
that are in excess of the square foot limits.
[2]
Editor's Note: Appendix C, Stormwater Best Management Practices Operations and Maintenance Agreement, is included as an attachment to this chapter. See also Appendix D, Small Project Stormwater Management Plan.
A.
The following regulated activities are specifically exempt from the
Stormwater Management Plan preparation and submission requirements
articulated in this chapter:
(1)
Agricultural activity limited to plowing or tilling activities, for
animal concentrated (heavy) use areas provided the activities are
performed according to the requirements of Chapter 102,[1] or conservation practices being installed as part of the
implementation of a Conservation Plan written by an NRCS or SCS-certified
planner. This exemption does not include any other type of earth disturbance
subject to NPDES permit requirements such as earth disturbance equal
to or greater than one acre.
[1]
Editor's Note: See 25 Pa. Code § 102.1 et seq.
(3)
Forest management and timber operations, provided the activities
are performed according to the requirements of applicable PA DEP regulations
and the Code of Unity Township.
(4)
Natural resource extraction activities, provided they are done in
accordance with applicable PA DEP regulations and the Code of Unity
Township.
(5)
Roadway resurfacing and maintenance projects, which do not increase
impervious area, and underground infrastructure projects are exempt
from the provisions of this chapter, provided the activities meet
the requirements of all other municipal, state and federal requirements.
(6)
Domestic landscaping and/or vegetable gardening.
(7)
Voluntary green infrastructure (GI) or the retrofit of stormwater
management infrastructure as conversion to green infrastructure BMPs
to correct existing problems, that are solely intended to better manage
runoff from existing development, are not part of new development
or redevelopment, and that do not fall under the requirements of this
or other development ordinances.
B.
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.
If the Township, in conjunction with the Township Engineer, WCD, or DEP as applicable, determines that any requirement under this chapter cannot be achieved for a particular regulated activity, the Township may, after an evaluation of alternatives, approve measures other than those in this chapter, subject to the terms of Subsections B, C and D hereafter and provided same are in compliance with all commonwealth laws and regulations. The request for a waiver, modification, or demonstrated equivalency shall originate with the landowner, shall be in writing, include a study of downstream effects, and accompany the Stormwater Management Plan submission to the Township. The request shall provide the facts on which the request is based, the provision(s) of the ordinance involved and the proposed modification or demonstrated equivalency. The Township Engineer and WCD shall review the request to determine if it meets the requirements of the ordinance, including, but not limited to, the provisions set forth in those applicable subsections set forth hereafter. If acceptable to the Township and WCD and the regulated stormwater activity involving earth disturbance is less than one acre AND new impervious surface is less than 1/2 acre, the Township may grant the waiver or modification. If the regulated stormwater activity involves new impervious surface of more than 1/2 acre, then a stormwater management plan meeting the full requirements of this chapter is required. If the regulated stormwater activity involving earth disturbance is equal to or greater than one acre, the plan will be subject to the NPDES requirements of DEP, regardless of the amount of new impervious area.
B.
Waivers, modifications, or the use of demonstrated equivalencies
of the requirements of this chapter may be approved by the Township
if strict compliance with the terms of this chapter will exact undue
hardship upon the developer. The burden of proving "undue hardship"
shall rest with the developer. In order to prove undue hardship, the
developer must prove to the satisfaction of the Township: 1) that
strict compliance with this chapter cannot be achieved because of
unique physical circumstances or preexisting site conditions peculiar
to the land in question; 2) that the modifications or demonstrated
equivalency will not be contrary or detrimental to the public health,
safety, welfare and/or interest, shall achieve the intended outcome
of this chapter, and preserve the purpose of this chapter; 3) that
the undue hardship is due to such unique physical circumstances or
preexisting site conditions and not the circumstances or conditions
generally created by the provisions of this chapter; 4) that there
is no reasonable possibility that the property can be developed in
strict conformity with the provisions of this chapter; and that the
hardship has not been created by the landowner or developer. The cost
or financial burden of complying with the terms of this chapter shall
not, in and of itself, be considered a hardship.
C.
No waiver, modification or demonstrated equivalency of any regulated
stormwater activity involving earth disturbance greater than or equal
to one acre may be granted by the Township unless that action is approved
in advance by the Department of Environmental Protection (DEP) or
the Westmoreland Conservation District (WCD).
D.
Applicants may request approval of a demonstrated equivalent stormwater
activity for their project in lieu of performing traditional stormwater
management. Demonstrated equivalent stormwater activity requests will
be evaluated by the Township Engineer and the WCD on a case-by-case
basis. Prior approval of a demonstrated equivalent stormwater activity
on a site does not set a precedent for future approval of the same
or other alternative activities on any site. The approval of a demonstrated
equivalent stormwater activity does not excuse the applicant from
following standard E&S and SWM practices as applicable on the
original site. Demonstrated equivalent stormwater activities shall
only be approved when the following criteria are met:
(1)
Traditional stormwater management activities on the site are precluded
by a particular site limitation, such as contaminated soil, steep
slopes, existing buildings/infrastructure, or a combined sewer;
(2)
Construction of traditional stormwater management activities on the
site would require extra permits or lead to excessive permitting activities
and delays;
(3)
The site in question does not already have a stormwater management
problem; and
(4)
The site in question is not already contributing to water quality
problems in the receiving stream.
E.
Approvable demonstrated equivalent stormwater activities may include
the following:
(1)
Restoration of an existing degraded wetland, stream channel, floodplain,
or riparian buffer, including daylighting of a stream.
(2)
Restoration, retrofit or upgrade of an existing stormwater management
feature (i.e., an inadequate detention pond, for example).
(3)
Creation of new stormwater management features, especially green
infrastructure, for a previously unmanaged site.
(4)
Providing a water-based benefit to the public other than stormwater
management (for example, extend a public sewer to an area not already
served).
(5)
Treatment of abandoned mine drainage.
F.
The proposal for demonstrated equivalency shall be accompanied by
documentation or methodology quantifying the equivalency of the proposed
project to what would have been originally required. Acceptable documentation
or methodology may include use of the Worksheets and Checklist found
in PA DEP NPDES permit application, Appendix D, or other approved
method which demonstrates that the proposed equivalency:
(1)
Controls approximately the same amount of runoff volume as what would
originally have been proposed;
(2)
Improves approximately the same amount of runoff quality as would
have been originally proposed;
(3)
Is located within an impaired watershed or stream segment which will
benefit from the proposed project. Impairment may include stream impairment,
reduced stream buffer, and pollutant loading. Refer to the Westmoreland
County Integrated Water Resources Plan at www.westmorelandstormwater.org.
G.
The demonstrated equivalent stormwater activity shall:
(1)
Be constructed concurrently with the project for which it is being
applied;
(2)
Be constructed according to plans approved by the Township and the
WCD, including any erosion control and stormwater management practices
as applicable;
(3)
Obtain and have issued all necessary permits;
(4)
Be located on land owned by or controlled by the applicant or by
a cooperating public or private entity(s) (school, church, club, Township,
etc.);
(5)
Be protected by a perpetual easement or deed restriction, or landowner
agreement;
(6)
Be located in the same general watershed as the project for which
it is being applied; and
(7)
Have an Operation and Maintenance (O&M) Plan and be subject to
an Operation and Maintenance Agreement specifying who is responsible
for what tasks.
A.
When a regulated development activity referenced in the table in § 99-15 of this chapter) creates impervious area between 1,000 and 3,000 square feet, or total earth disturbance between 3,000 and 5,000 square feet, the stormwater management requirements of this section shall be applied.[1]
[1]
Editor Note: Refer also to Appendix D, which is included as an attachment to this chapter.
B.
For new impervious surfaces, the first one inch of runoff shall be
permanently removed from the runoff flow and shall not be released
to waters of the commonwealth. Removal options include reuse, evaporation,
transpiration and infiltration.
C.
Facilities, to the greatest extent possible and subject to Township
approval, shall be designed to drain the permanently removed runoff
volume in a period no greater than 72 hours. Runoff volumes in excess
of one inch shall be safely conveyed to a stable vegetated area, natural
watercourse, the curb or gutter line of roadway or existing storm
collection/conveyance/control system as applicable.
D.
This method may, at the discretion of the Township, be exempted from full compliance with all or parts of the requirements of § 99-26 of this chapter, based on the circumstances of the plan, the nature of the regulated development activity occurring on the property and the effectiveness of the proposed controls.
(1)
A Small Project Stormwater Management Plan must be submitted to the Township and the WCD consisting of the following items and related support material needed to determine compliance with §§ 99-19 through 99-24 of this chapter.[2] The Small Project Stormwater Management Plan submitted
must contain:
(a)
A narrative containing a general description of proposed stormwater
management techniques, including calculations, assumptions and criteria
used in the design of the stormwater management facilities and BMPs,
and construction specifications of the materials to be used for stormwater
management facilities and BMPs.
(b)
A Stormwater Management Plan, showing the locations of all stormwater
management facilities and BMPs, especially green infrastructure, limits
of disturbance, including the type and amount of proposed impervious
area, structures, roads, paved areas and buildings;
(c)
A Small Project Stormwater Management Worksheet;
(d)
A signed agreement page for operation and maintenance of stormwater
facilities and BMPs in the form attached hereto as Appendix B[3] or, where determined by the Township to be appropriate,
a BMP Operation and Maintenance Agreement in the form attached hereto
as Exhibit "C"[4]; and
[3]
Editor's Note: Appendix B, Landowner Acknowledgement for Small Projects, is included as an attachment to this chapter.
[4]
Editor's Note: See Appendix C, included as an attachment to this chapter.
(e)
An Erosion and Sediment Control Plan, including all reviews
and letters of adequacy from the Conservation District.
[2]
Editor Note: The applicant may also utilize those protocols listed in Appendix D, which is included as an attachment to this chapter.
A.
Proposed land development must consider avoiding, minimizing, and
mitigating impacts to the site that may increase stormwater runoff
from the proposed project. Applied sequentially, the low-impact development
strategies set forth hereafter should be used as an overall guide
as a project is planned and carried out. The Westmoreland County Integrated
Water Resources Plan also provides an online decision-making tool
to assist developers, designers and property owners in addressing
all water resources during development and redevelopment and should
be consulted.[1]
[1]
Editor Note: Refer to www.paiwrp.com and www.westmorelandstormwater.org.
B.
All stormwater management plans shall be designed and evaluated using
the following standards:
(1)
Any landowner and any person engaged in the alteration or development
of land which may affect stormwater runoff characteristics shall implement
such measures as are reasonably necessary to prevent injury to health,
safety or other property. For alteration or development taking place
in stages, the cumulative development must be used in determining
conformance with this chapter. Such measures shall include actions
necessary and reasonable:
(a)
To ensure that the maximum rate of stormwater runoff is no greater
after development than prior to development activities for the one-,
two-, five-, ten-, twenty-five-, fifty-, one-hundred-year storms having
rainfall durations of 24 hours. Calculations shall be based on rainfall
data obtained from NOAA Atlas 14 or other source approved by the Township.
(b)
To manage the water quality, rate, volume and direction of resulting
stormwater runoff in a manner which otherwise adequately protects
health and property from possible injury.
(c)
To notify adjacent property owners or owners of affected properties
of any alteration or increase of stormwater flows.
(2)
Runoff treatment BMPs must be employed where necessary to ensure
the water quality, rate and volume requirements are met.
(3)
Volume control BMPs shall be used to maintain existing hydrologic
conditions for small storm events by promoting groundwater recharge
and/or evapotranspiration. Runoff volume controls shall be implemented
using the PA DEP Stormwater BMP Manual 2006 or other approved method
such as those listed in the following chart:
Acceptable Computation Methodologies for Stormwater Management
Plans
| ||
---|---|---|
Method
|
Developed By
|
Applicability
|
Win TR-20 (or commercial computer package based on TR-20)
|
USDA NRCS
|
Applicable where use of full hydrologic computer model is desirable
or necessary
|
Win TR-55 (or commercial computer package based on TR-55, i.e.,
VT/PSUHM)
|
USDA NRCS
|
Applicable for land development plans within limitations described
in TR-55
|
HEC-1, HEC-HMS
|
U.S. Army Corps of Engineers
|
Applicable where use of full hydrologic computer model is desirable
or necessary
|
PennDOT 584 (based on rational method)
|
PennDOT
|
Applicable under standards established by PennDOT; not to be
used for runoff volume and pond sizing computations.
|
EFH2
|
USDA NRCS
|
Applicable in agricultural areas subject to the program limits
|
SWMM
|
EPA
|
Applicable in urban and suburban areas subject to limits established
by EPA
|
PA DEP BMP Manual 2006
|
PA DEP
|
Applicable under standards established by PA DEP
|
Other methods
|
Varies
|
Other methodologies approved by the Township
|
C.
The project plan must specify the permanent stormwater BMPs to be
implemented, operated and maintained to meet legal water quality,
rate and volume requirements. If methods other than low-impact development
(LID) and green infrastructure methods are proposed to achieve the
volume and rate controls required under this chapter, the SWM Site
Plan must include a detailed justification demonstrating that the
use of LID and green infrastructure is not practicable.
D.
In order to protect and maintain water quality, additional stormwater
runoff created by the development project must be captured, stored
and treated. In addition, post-construction stormwater infiltration
of runoff must replicate preconstruction infiltration of runoff to
the maximum extent possible with the exception of hot spots. As a
minimum, this shall be a volume of additional runoff generated by
a two-year, twenty-four-hour storm. Preferred BMPs for a hot spot
include, but are not limited to, storm inlet filters, proprietary
stormwater quality devices, underground detention tanks, detention
ponds with forebays, tree planting, green roof. Permeable pavement,
infiltration BMPs, and rain gardens are not recommended for hotspots.
E.
In addition to the provisions set forth in Subsections A through D as set forth above, all regulated development activities within the Township shall be designed, implemented, operated and maintained to meet the purposes of this article, through:
(1)
Erosion and sediment control during the earth disturbance activities
(e.g., during construction); and
(2)
Water quality, rate and volume protection measures to be implemented
after completion of earth disturbance activities (e.g., post-construction
stormwater management), including operations and maintenance.
F.
No regulated development activities within the Township shall commence
until the requirements of this chapter are met.
G.
All best management practices (BMPs) used to meet the requirements
of this chapter shall conform to the state water quality requirements
and any more stringent requirements as determined by the Township.
H.
LID and green infrastructure techniques described in the PA DEP Stormwater
BMP Manual 2006 or most current edition are encouraged.
I.
Proposed projects must comply with the Township's approved MS4
permit, including compliance with the six minimum control measures
(MCMs) and with the Township's Pollutant Reduction Plan (PRP).
A.
The stormwater management performance standards in this article are
intended to implement the provisions, standards and criteria contained
in the Pennsylvania Storm Water Management Act (Act 167), 32 P.S. § 680.1
et seq. If there is any discrepancy between the provisions of this
article and the provisions, standards and criteria of the Act, or
if a stormwater management plan is subsequently approved and adopted
by the appropriate governmental agency or body, then the provisions,
standards and criteria of the current watershed plan shall govern.
B.
Management of stormwater runoff is a key objective of 25 Pa. Code Chapter 93 of the DEP Regulations because runoff can change the physical, chemical and biological integrity of water bodies, thereby impacting rate, volume and water quality. Accordingly, the project plan shall describe how these rate, volume and water quality protection requirements will be met. Infiltration BMPs shall be evaluated and utilized to the maximum extent possible to manage the net change in stormwater runoff generated so that post-construction discharges do not degrade the physical, chemical or biological characteristics of the receiving waters. These BMPs may be used to satisfy all or part of the requirements found within this chapter.
C.
Reference should be made to the Stormwater Performance Districts
outlined in Appendix A,[1] and the Westmoreland County Integrated Water Resources
Plan (IWRP) at www.westmorelandstormwater.org. The project plan shall
describe how the proposed project will address performance standards,
impairments, and pollutant loading found in the IWRP. For areas not
covered by a stormwater performance district, the release rate shall
be 80% of the pre-development peak flow as set by the Township.
[1]
Editor's Note: Appendix A is included as an attachment to this chapter.
A.
General criteria.
(1)
Applicants may select runoff control techniques, or a combination
of techniques, which are most suitable to control stormwater runoff
from the development site. Refer to the Acceptable Computation Methodologies
for Stormwater Management Plans table of this article.[1] All controls must be subject to approval of the Township
Engineer and the WCD. The Township Engineer may request specific information
on design and/or operating features of the proposed stormwater controls
in order to determine their suitability and adequacy in terms of the
standards of this chapter.
(2)
If the proposed development site is located in an impaired water
shed according to Category four of the PA Integrated Water Quality
Monitoring and Assessment Report, or in a watershed with a TMDL according
to Category 5 of the same report, the applicant shall identify the
source and cause of impairment and shall propose, if required or applicable
the use of BMPs to mitigate any impacts to the waters.
(3)
The applicant should consider the effect of the proposed stormwater
management techniques on any special soil conditions or geological
hazards which may exist on the development site. In the event such
conditions are identified on the site, the Township Engineer may require
in depth studies by a competent geotechnical engineer. Not all stormwater
control methods may be advisable or allowable at a particular development
site.
(4)
The applicant shall consider the effect of the proposed stormwater
management techniques on existing stream impairments and pollutant
loading. Reference should be made to the Westmoreland County Integrated
Water Resources Plan (IWRP) at www.westmorelandstormwater.org.
(5)
The applicant shall consider existing conditions on the site for
the prior five years to determine prevailing land use and impervious
cover, and shall consider 20% of existing impervious cover as meadow
for preexisting conditions on redevelopment sites.
(6)
The Hydrologic Soil Group (HSG) used for existing soils shall be
assumed to be for drained conditions. As an example, a soil identified
in the USDA NRCS soil survey as HSG B/D shall be assumed to be HSG
B soil unless information, such as infiltration testing and groundwater
monitoring data, is presented that justifies the use of HSG D soil.
(7)
For post-development conditions of sites that are undeveloped, the
HSG for each disturbed soil shall be reduced by one HSG level relative
to its HSG reported in the USDA NRCS soil survey in order to account
for compaction of the soil due to earthmoving activities, unless specific
accommodations are employed, such as deep-tilling (or subsoiling)
and soil amendment, to counter against the soil compaction that normally
results due to typical earthmoving activities.
(8)
The stormwater management practices to be used in developing a stormwater
management plan for a particular site shall be selected giving deference
to the criteria set forth hereafter in the following order of preference:
(a)
Site planning for locating proposed buildings, impervious areas
and grading which minimizes disruption of the natural site characteristics
especially utilizing low-impact development techniques.
(b)
Minimization of impervious areas and promotion of retentive
grading.
(c)
Implementation of nonstructural measures (refer to the PA DEP
Stormwater BMP Manual 2006 or current edition).
(d)
Implementation of innovative/green infrastructure structural
measures (refer to the PA DEP Stormwater BMP Manual 2006 or current
edition).
(e)
Stormwater detention/retention structures.
(9)
Any BMP which is a dam, culvert, stream obstruction or encroachment
or outfall as defined in 25 Pa. Code Chapter 105 shall be designed
according to the requirements in those regulations.
(10)
Drainage easements shall be provided for all stormwater conveyance
and BMPs serving multiple properties and not located within a public
right-of-way. Easements shall include ingress and egress to a public
right-of-way, and shall be recorded at the county with the final plan.
Terms of easement shall prohibit excavation or placement of fill or
structures and any alteration that may adversely affect the flow of
stormwater within any portion of the easement.
(11)
No person shall install, create, modify, remove, fill, landscape
or otherwise alter or place any structure, soil, rock, material or
vegetation in or on, or otherwise adversely affect, any stormwater
management facility or any area within a stormwater easement without
the written approval of the Township and approval of the WCD.
(12)
Persons engaged in land development activities shall provide
the required financial Security and O&M Agreements to the Township
as outlined in this chapter.
B.
Criteria and considerations for stormwater management facilities
and BMPs.
(1)
If stormwater management facilities and BMPs are utilized for the
development site, the facility(s) shall be designed such that post-development
peak runoff rates from the developed site are controlled to those
rates defined by a Stormwater Management Performance District for
the one-, two-, five-, ten-, twenty-five-, fifty-, one-hundred-year
storm frequencies having rainfall durations of 24 hours. Rainfall
data shall be obtained from NOAA Atlas 14 or other source as approved
by the Township.
(2)
All stormwater management facilities and BMPs shall be equipped with
outlet/overflow structures to provide rate discharge control for the
designated storm frequencies. Provision shall also be made to safely
pass the entire post-development one-hundred-year storm without breaching
or otherwise damaging the facilities, downstream or neighboring properties.
(3)
Release of stormwater flow from a development site must be to an
existing stormwater conveyance or easement, whether natural or man-made,
that has defined bed and banks. Calculations and information shall
be presented as to the ownership, responsible party, capacity, and
stability of such conveyance. Release of "sheet flow," as from a level
spreader, will be permitted on a case-by-case basis as approved by
the Township Engineer and the WCD.
(4)
All stormwater management facilities and BMPs shall be designed to
control volume and water quality as defined by the Stormwater Management
Performance District referenced in Appendix A.[2]
[2]
Editor's Note: Appendix A is included as an attachment to this chapter.
(5)
Shared stormwater management facilities and BMPs, which provide control
of runoff for more than one development site within a single sub-area
may be considered and are encouraged. Such facilities shall meet the
criteria contained in this section. In addition, runoff from the development
sites involved shall be conveyed to the facility in a manner that
avoids adverse impacts (such as flooding or erosion) to channels and
properties located between the development site and the shared storage
facilities.
(6)
Where stormwater management facilities and BMPs will be utilized,
multiple use facilities, such as wetlands, lakes, ball fields or similar
recreational/open space uses are encouraged wherever feasible, subject
to the approval of the Township.
(7)
Other considerations which must be incorporated into the design of
the stormwater management facilities and BMPs include:
(a)
Inflow and outflow structures designed and installed to prevent
erosion and embankments, cuts, fills and bottoms of impoundment type
structures should be protected from soil erosion.
(b)
Control and removal of debris both in the storage structure
and in inlet or outlet devices.
(c)
Inflow and outflow structures, pumping stations and other structures
designed and protected, using safety benches, trash racks, energy
dissipaters and other means to minimize safety hazards.
(d)
Access restrictions include fencing, with at least one lockable
ingress and egress gate, in a minimum height of six feet shall be
required at the discretion of the Township and the Township Engineer.
(e)
Interior slopes of storage ponds not exceeding a ratio of three
to one horizontal to vertical dimension with a combination of interior
and exterior slopes not exceeding five. Steeper slopes may be approved
by the Township Engineer if documented to be stable by a geotechnical
analysis prepared by, or under the direction of, and sealed by a licensed
geotechnical engineer.
(f)
Pond principal spillways consisting of a solid reinforced concrete
box (riser) that is designed and constructed to control the flow rate
out of the detention facility. Noncorrugated plastic pipe may be used
for the riser where the riser height is less than three feet and the
plastic pipe is properly anchored to prevent horizontal or vertical
displacement. The riser shall be joined by a watertight connection
to a horizontal reinforced concrete pipe or high-performance polypropylene
pipe (barrel) extending through the embankment and out-letting beyond
the downstream toe of the fill. The maximum capacity of the barrel
will be the twenty-five-year post-development flow. The construction
materials must be approved by the Township Engineer.
(g)
Pond dam embankments consisting of all excavation on the project,
except such material as may be determined unsuitable by the Township
Engineer, which includes, but is not limited to, frozen material,
organic material, rock in excess of three inches in diameter, construction
debris, sandy or other coarse grained soils, noncompactable soils
and excessively wet or dry material. Acceptable material shall conform
to the current PennDOT Publication 408 section on embankment material
or shall be as approved by the Township Engineer. The pond dam embankment
shall be compacted to a minimum 95% standard proctor maximum dry density
as per ASTM D698. The embankment shall be constructed and compacted
in maximum eight-inch lifts and the principle spillway outfall barrel
and anti-seep collar(s) shall be constructed integral with the dam
embankment construction.
(h)
Landscaping facilities which stabilize disturbed areas and preserves
the natural and beneficial values of the surrounding area. Landscaping
shall consist of plant species native to southwestern Pennsylvania.
No trees or other woody vegetation shall be planted on the fill areas
of the pond dam embankment that may result in loosening of the compacted
soils of the embankment. Detention basin bottoms shall be vegetated
with a diverse native planting mix and may include trees, woody shrubs
and meadow/wetland herbaceous plants. Noxious and invasive plants
that inhibit plant species diversity shall not be included in the
plant mix. PennDOT seed mix Formulas B, C, D and L as per PennDOT
Publication 408 latest revision, or approved equivalent mix shall
be used for revegetation of embankment areas. Crownvetch and birdsfoot
trefoil shall not be used due to their interference with performance
of inspections of the dam embankment. For other suitable landscape
plant species, refer to Appendix B of the Pennsylvania Stormwater
Best Management Practices Manual, latest edition.
(i)
Facilities shall be located to facilitate maintenance, considering
the frequency and type of equipment that will be required.
(j)
Underground detention/retention/infiltration facilities shall
be equipped with open grate inlet(s), inspection ports and/or manhole
access to facilitate visual inspections and maintenance. Other considerations
which should be incorporated into the design of the detention facilities
include the following:
[1]
Inflow and outflow structures must be designed and installed
to prevent erosion, and bottoms of impoundment-type structures should
be protected from soil erosion.
[2]
All inflow structures into detention/retention ponds must discharge
into a pond forebay designed in accordance with the Pennsylvania Stormwater
Best Management Practices Manual.
[3]
Control and removal of debris both in the storage structure
and in all inlet or outlet devices.
[4]
Inflow and outflow structures, pumping stations and other structures
must be designed and protected to minimize safety hazards.
[5]
The water depth at the perimeter of a storage pond should be
limited to that which is safe for children. This is especially necessary
if bank slopes are steep or if ponds are full and recirculating in
dry periods. Restrictions of access (fence, walls, etc.) shall be
necessary, depending on the location of the facility.
[6]
A safety bench with a minimum width of eight feet must be provided
around the entire interior perimeter of the pond at an elevation of
six inches minimum above the two-year peak water surface elevation
in the pond.
[7]
An anti-vortex device and trash rack must be attached to the
top of the principal spillway to improve the flow of water into the
spillway and prevent floating debris from being carried out of the
basin.
[8]
The base of the principal spillway must be firmly anchored to
prevent its floating. Computations must be made to determine the anchoring
requirements. As a minimum, a factor of safety of 1.25 shall be used
(downward forces = 1.25 x upward forces).
[9]
The barrel of the principal spillway, which extends through
the embankment, must be designed to carry the twenty-five-year pre-development
flow provided by the riser of the principal spillway with the water
level at the crest of the emergency spillway. The barrel shall consist
of a reinforced concrete pipe (RCP) or high-performance polypropylene
(HPPP) pipe and shall be fully supported along its entire length by
a concrete cradle extending to the center line of the pipe and projecting
horizontally a minimum of six inches beyond the outside wall of the
pipe and vertically six inches below the bottom of the pipe. The connection
between the riser and the barrel must be watertight. The outlet of
the barrel must be protected to prevent erosion or scour of downstream
area. This will include an end section or end wall with a designed
rip-rap apron. For principle spillway barrels that pass through compacted
fill pond dam embankments, the barrel, cradle and anti-seep collar(s)
shall be constructed integral with the dam embankment construction
as opposed to cutting into the completed dam embankment to construct
the barrel, etc.
[10]
Anti-seep collars.
[a]
Anti-seep collars shall be used on the barrel of
the principal spillway within the normal saturation zone of the embankment
to increase the seepage length by at least 10% if either of the following
conditions is met:
[b]
The anti-seep collars must be installed within
the saturated zone. The maximum spacing between collars shall be 14
times the projection of the collar above the barrel. Collars shall
not be closer than two feet to a pipe joint. Collars should be placed
sufficiently far apart to allow space for hauling and compacting equipment.
Collars shall consist of reinforced concrete with a minimum thickness
of eight inches. Connections between the collars and the barrel shall
be watertight.
[11]
The emergency spillway must consist of an open channel having
a control section at least 20 feet in length. The control section
is a level portion of the spillway channel at the highest elevation
in the channel. The emergency spillway shall be designed to carry
the peak rate of runoff expected from the entire post-development
one-hundred-year storm to the stormwater facility. The spillway channel
shall be located so as to avoid sharp turns or bends. The channel
shall return the flow of water to a defined channel downstream from
the embankment. At the discretion of the Township Engineer and/or
WCD, the emergency spillway shall include a reinforced concrete grade
control wall extending perpendicular to the flow through the spillway
with the top of the wall flush with the spillway crest. This control
wall shall have a minimum width of eight inches, extend a minimum
of 18 inches below the spillway crest and have a length no less than
the width of the emergency spillway opening at the top of dam. The
emergency spillway shall provide a minimum one foot of freeboard between
the water surface of the full one-hundred-year post-development discharge
through the spillway and the top of the dam embankment.
C.
Criteria for collection/conveyance facilities.
(1)
All stormwater runoff collection or conveyance facilities, whether
storm sewers or other open or closed channels, shall be designed in
accordance with the following basic standards:
(a)
All building sites shall use measures to provide drainage away
from and around the structure in order to prevent any potential flooding
damage as much as practical. Such measures shall include grading the
surrounding lawn or pavement area so that it slopes away from the
structure by a minimum of 5% slope over a minimum distance of six
feet; raising the floor of the structure so that it is a minimum of
six inches above the predominant surrounding land elevation and above
the designated floodplain elevation for those located within a floodplain;
eliminating or waterproofing penetrations thru the structure's
walls or foundation; constructing berms, curbs, or swales to divert
surface water around the structure; arranging roof and area drains
to carry water away from the structure.
(b)
Developers proposing a land development or subdivision shall
arrange internal drainage within the subdivision so that surface water
is safely directed and channeled away from all structures within and
adjacent to the development site.
(c)
Developers shall provide to all persons constructing a structure
within a land development site, standards, including drawings and
specifications to ensure that those persons adhere to the general
site plans and stormwater management plans for the development. Persons
constructing a structure within a land development site shall submit
to the Township Engineer and WCD drawings, calculations, and other
information to show how they will meet the stormwater management requirements
of the development site.
(d)
Lots located on the high side or low side of streets shall extend
roof, trench and area drains to a stable vegetated area, natural watercourse,
the curb or gutter line of roadway or storm collection/conveyance/control
system (if applicable) in accordance with the approved stormwater
management plan for the development site.
(e)
For all building sites and lots, the inclusion of rain barrels,
rain gardens, dry wells and other strategies for infiltration of roof
runoff close to its source is encouraged.
(f)
Collection/conveyance facilities should not be installed parallel
and less than 10 feet from the top or bottom of an embankment, greater
than or equal to 15 feet in height to avoid the possibility of failing
or causing the embankment to fail, unless documented to be stable
by a geotechnical analysis.
(g)
All collection/conveyance facilities shall be designed to convey
the twenty-five-year storm peak flow rate from the contributing drainage
area to the nearest suitable outlet such as a stormwater control facility,
curbed street, storm sewer or natural watercourse. However, the one-hundred-year
design storm may be required as determined by the Township Engineer
where it is necessary for the storm system to convey the one-hundred-year
design storm to the stormwater management facility.
(h)
Where drainage swales or open channels are used, they shall
be suitably lined to prevent erosion and designed to avoid erosive
velocities.
(i)
Wherever storm sewers are proposed to be utilized, they shall
comply with the following additional criteria:
[1]
Where practical, same shall be designed to traverse under seeded
and planted areas. If constructed within 10 feet of road paving, walks
or other surfaced areas, drains shall have a narrow trench and maximum
compaction of backfill to prevent settlement of the superimposed surface
or development.
[2]
Preferably, same shall be installed after excavating and filling
in the area to be traversed is completed, unless the drain is installed
in the original ground with a minimum of three feet cover and/or adequate
protection during the fill construction.
[4]
Designed to adequately handle the anticipated stormwater flow
and be economical to construct and maintain. The minimum pipe size
shall be 15 inches in diameter, with the exception of roof drains,
foundation drains, internal french drains and/or sump pumps, or similar
conveyances.
[5]
Drain pipe, trenching, bedding and backfilling requirements
and appropriate grates, catch basins, stormwater inlets, manholes
and other appurtenances shall conform to the requirements of the Township
and/or applicable PennDOT specifications, Publication 408.
[6]
All corrugated metal pipe shall be polymer coated, and with
paved inverts where prone to erode. Pipe within a Township right-of-way
shall be reinforced concrete pipe or high-performance polypropylene
pipe with a diameter sufficient to accept existing and reasonably
anticipated future stormwater capacity and in no event less than the
minimum diameter of 15 inches.
[7]
All storm pipes constructed within existing Township rights-of-way
or in new developments whose roads and associated storm sewers may
be taken over by the Township are to consist of straight runs of pipe
only, both horizontally and vertically, between storm structures such
as inlets, manholes and/or end walls. No storm sewers consisting of
blind elbows, blind tees or pipe joint deflections, such as for pipes
following the horizontal curve of a roadway, will be acceptable for
takeover by the Township.
[8]
Storm inlets and structures shall be designed to be adequate,
safe, self-cleaning and unobtrusive and consistent with Township standards
with sufficient capture and conveyance capacity and spacing of inlets
and cleanouts for maintenance.
[9]
Where a proposed sewer or conveyance connects with an existing
storm sewer or conveyance system, the applicant shall demonstrate
that sufficient capacity exists in the downstream system to handle
the additional flow.
[10]
Storm sewer outfalls shall be equipped with energy dissipation
devices to prevent erosion and conform with applicable requirements
of the Pennsylvania DEP for stream encroachments (Section 7 of the
Dam Safety and Encroachments Act, 32 P.S. § 693.1 et seq.,
and the rules and regulations promulgated thereunder at 25 Pennsylvania
Code §§ 105.441 to 105.449). Exit velocities of the
design storm for the stormwater conveyance systems must be considered
in the design of the energy dissipation devices.
[11]
Storm inlets shall include castings with the message "Dump No
Waste. Drains to Stream" or similar message as approved by the Township
Engineer cast into or permanently affixed to the casting and positioned
in a manner that is legible to pedestrian traffic.
D.
Criteria for riparian buffers.
(1)
If a riparian buffer is required by PA DEP as part of an NPDES permit,
then DEP regulations will govern.
(2)
If a riparian buffer is used to meet stormwater management requirements
and/or MS4 pollutant load reduction credits, it shall meet the following
requirements:
(a)
In order to protect and improve water quality, a riparian buffer
easement must be created and recorded as part of any subdivision or
land development that encompasses a riparian buffer.
(b)
Except as required by Pa. Code Title 25, Chapter 102, the riparian
buffer easement shall may be measured to a minimum of 35 feet measured
from the top of the nearest bank (on each side), or an average of
35 feet with no distance from top of bank less than 25 feet.
(c)
Minimum management requirements for riparian buffers shall require:
[1]
Existing native vegetation to be protected and maintained within
the riparian buffer easement.
[2]
Whenever practicable, invasive vegetation to 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.
[3]
No earth disturbance beyond which is necessary to establish
or maintain a planted buffer.
(3)
The riparian buffer easement shall be recorded in the Westmoreland County Recorder of Deeds Office, run with the land, limit the use of the property located therein and shall be enforceable by the Township. The easement shall allow for the continued private ownership by the property owner and shall counted as part of the minimum lot area required by Chapter 118, Zoning, unless specified otherwise in an applicable Township ordinance.
(4)
Any permitted use within the riparian buffer easement shall be conducted
in a manner that will maintain the extent of the existing one-hundred-year
floodplain, improve or maintain the stream stability, and preserve
and protect the ecological function of the floodplain.
(5)
Stormwater drainage pipes and all other linear utility lines as approved
by the Township shall be permitted within the riparian buffer easement,
but shall cross the easement in the shortest practical distance. Other
stormwater management facilities and BMPs are not permitted within
the riparian buffer easement.
(7)
Septic drain fields 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.
E.
Criteria for stream restoration projects.
(1)
A stream restoration project may eligible for stormwater management
and/or MS4 load reduction credits if it meets the following qualifying
criteria:
(a)
Existing conditions, such as channel or stream bank erosion
and an actively enlarging or incising urban stream condition, are
documented prior to restoration.
(b)
Projects should be located on first- to third-order (small)
streams to be effective.
(c)
The project addresses a minimum of 100 linear feet of stream
channel and both sides where need to do so is evident.
(d)
Upstream impervious area should be sufficiently treated to address
peak flows that may exceed engineering design thresholds or compromise
channel form and function.
(e)
A comprehensive approach employing a mix of techniques appropriate
to the site, creating long-term stability of the streambed, stream
banks and floodplain is utilized.
(f)
Armored length of streams (i.e., using riprap or gabions) are
used to maintain channel stability, and the same length is not included
in the load reduction calculation.
(g)
The project maximizes floodplain reconnection, with minimal
channel invert elevation increase (i.e., bank height ratio = 1.0 or
less) to achieve the objective.
(h)
The project includes a minimum thirty-five-foot permanent riparian
buffer.
(i)
The project includes an O&M plan identifying O&M activities,
frequencies and responsible parties.
A.
Excavation standards.
(1)
No excavation shall be made with a cut face steeper in slope than
two horizontal to one vertical except under one or more of the following
conditions:
(a)
The excavation is located so that a line having a slope of two
horizontal to one vertical and passing through any portion of the
cut face will be entirely inside the property lines of the property
on which the excavation is made.
(b)
The material in which the excavation is made is sufficiently
stable to sustain a slope steeper than two horizontal to one vertical
and a written statement of a professional engineer, licensed by the
Commonwealth of Pennsylvania and experienced in erosion control to
that effect is submitted to the Code Official and approved by him.
The statement shall state that the engineer has inspected the site
and that the deviation from the slope specified above will not result
in increased risk of injury to persons or damage property.
(c)
A retaining wall or other approved support designed by a registered
professional engineer and said design approved by the Code Official
is provided to support the face of the excavation.
(2)
The Code Official may require an excavation to be made with a cut
face less (flatter) in slope than two horizontal to one vertical if
he finds that the material in which the excavation is to be made is
unusually subject to erosion or if other conditions exist which, under
applicable engineering practice, make such flatter cut slope necessary
for stability and safety.
(3)
Excavations adjacent to any footing, foundation, or structure shall
not extend below the angle of repose or natural slope of the soil
under the nearest point of the same unless such footing, foundation,
or structure is first properly underpinned or protected against settlement.
(4)
Before commencing any excavation which will in any way affect an
adjoining property or structure thereon, the person making or causing
the excavation to be made shall notify, in writing, the owners of
adjoining buildings not less than 30 days before such excavation is
to be made. Adjoining properties and structures shall be protected
as provided in the Unity Township Building Code and/or as required
by the Code Official.
B.
Fill standards.
(1)
No fill shall be made which creates any exposed surface steeper in
slope than two horizontal to one vertical, except under one or more
of the following conditions:
(a)
The fill, in the opinion of the Code Official, is located so
that settlement, sliding, or erosion of the fill material will not
result in property damage or be a hazard to adjoining property, streets,
alleys, or structures.
(b)
A written statement of a professional engineer licensed by the
Commonwealth of Pennsylvania and experienced in erosion control to
that effect is submitted to the Code Official and approved by him.
The statement shall state that the site has been inspected by such
engineer and that the deviation from the slope specified above will
not result in increased risk of injury to persons or damage property.
(2)
The Code Official may require that the fill be constructed with an
exposed slope less (flatter) than two horizontal to one vertical if
he finds that under the particular conditions such flatter slope is
necessary for stability and safety.
(3)
Whenever a fill is to be made of materials other than clean soil
or earth, the grading permit shall be subject to the following additional
limitations and requirements:
(a)
The fill shall be completed within a reasonable length of time,
said time limit to be determined by the Code Official and to be specified
on the grading permit.
(b)
Clean soil or earth shall be placed over the top and exposed
surfaces of the fill to a depth sufficient to effectively conceal
all materials, other than clean soil or earth, within the fill.
(4)
When the fill is other than clean soil or earth, the Code Official
may require clean soil or earth to be placed over the top and exposed
surfaces of the fill to a depth sufficient to conceal all materials
at the end of each day's operations.
(5)
No fill of any kind shall be placed over trees, stumps, or other
material which would create a nuisance or be susceptible to attracting
rodents, termites, or other pests.
(6)
All fills shall be compacted to provide stability of material and
to prevent undesirable settlement.
(7)
The fill shall be spread in a series of layers, each not exceeding
12 inches in depth, and shall be compacted by a sheep's-foot
roller or other approved method after each layer is spread.
(8)
Where fills are placed on slopes of 5% or more, benching of the surface
shall be required and indicated on the cross sections.
(9)
The Code Official may require tests or other information if, in their
opinion, the conditions or materials are such that additional information
is necessary.
(10)
The movement of earth in the course of farming or agricultural
work or private landscaping.
C.
Ground cover.
D.
Drainage.
(1)
Adequate provisions shall be made to prevent any surface waters from
damaging the cut face of an excavation or the sloping surface of a
fill.
(2)
The Code Official shall require such drainage structures or pipes
to be constructed or installed which are necessary to prevent erosion
damage and to satisfactorily carry off surface waters.
(3)
All drainage provisions shall be of such design so that the peak
discharge for all stormwater outfalls on site shall be in conformance
with the performance standards set forth herein.
E.
Maintenance.
(1)
The owner of any property on which an excavation or fill has been
made shall maintain in good condition and repair all retaining walls,
cribbing, drainage structures, fences, ground cover, and other protective
devices as established by permit, and, further, the continued use
of said area shall be contingent upon the maintenance and upkeep of
same in a condition satisfactory to the Township, and subject to such
further conditions as the Township may prescribe.
(2)
The certificate of completion may at any time be revoked by the Board
of Supervisors, in accordance with the procedures set forth hereafter,
if the conditions of the permit are not being observed or if conditions
exist that prejudice or pose a threat to the health, safety, and welfare
of any person, persons, or property.
F.
Protection of adjacent property and utilities.
(1)
Prevention of slides or washes. Materials shall not be permitted
to roll, slide, flow, or wash onto adjacent private or public property.
Where necessary, walls, cribbing, silt fence, or benching shall be
utilized to comply with this requirement.
(2)
Horizontal distance of excavation or fill slope from property or
easement line.
(a)
The horizontal distance from the toe or top of the excavation
or fill slope line shall be five feet or 1/2 of the vertical height
of the fill or excavation from any adjoining property or easement
line, whichever is greater, but such distance need not exceed 10 feet.
(b)
The Code Official shall have the authority to modify this requirement
in instances where it is demonstrated that such modification is needed
to secure desirable interrelationships between properties and will
not result in a condition detrimental to the adjacent property.
(3)
Support and protection of public utilities and public streets.
(a)
A plan shall be in effect for proper support and protection
from drainage resulting from the operation for all public and private
utilities, whether on the surface, beneath the ground surface, or
overhead, and, when necessary, for the repair, replacement, or relocation
of such utilities.
(b)
The surface and other facilities or public streets shall be
fully restored by the permit holder in the event of such damage.
(c)
The permit holder shall correct any damage to the utility involved
before the Code Official issues the completion certificate.
G.
Fencing. Should the nature of land operations, in the opinion of
the Code Official, create a hazard to persons or property unless adequately
fenced, the permit holder shall construct such fences or guide rails
as safeguards to persons using adjoining property, public or private.
H.
General requirements.
(1)
Any excavations within a floodway or floodplain must follow the guidelines
as set forth in the floodplain management regulations of the Township
Code.
(2)
A temporary construction fence not less than four feet in height,
or a design approved by the Code Official and/or meeting other Township
fence requirements, shall be placed at the top of all cuts or fills
with slopes in excess of two horizontal to one vertical.
(3)
The permit holder and owner of a property shall be responsible to
protect and clean up lower properties of silt or debris washing from
his property as a result of the regrading of his property.
(4)
In order to prevent the denuding of the landscape, large trees and
other natural features constituting important physical, aesthetic,
and economic assets to existing or impending suburban development
shall be preserved.
(5)
All grading, excavating, or fill shall be performed so that no unnecessary
dust shall be raised. The Code Official may enforce reasonable dust-control
regulations and may revoke any permit issued under this chapter until
proper dust-control regulations are met.
I.
Certificate of completion.
(1)
If, upon final inspection of an excavation or fill, it is found that
the work authorized by the permit has been satisfactorily completed
in accordance with the requirements of this chapter, a certificate
of completion covering such work and stating that the work is approved
shall be issued to the permit holder by the Code Official.
(2)
The Board of Supervisors shall have the power to revoke any certificate
of completion upon the recommendation of the Code Official that the
work covered by the certificate has been materially extended or altered
without a permit to do so, or that any retaining walls, cribbing,
drainage structures, fences, or other protective devices shown on
the approved plans and specifications submitted for a permit have
not been maintained in good order and repair.
(3)
Before such revocation, the Code Official shall first give written
notice to the permit holder and to the owner of the property involved,
specifying the defective condition and stating that, unless such defective
condition is remedied, the certificate may be revoked. If the defective
condition is remedied, the certificate shall not be revoked. Such
conditions shall be corrected within 30 days' notice to the owner
to correct the same, or within a shorter period of time established
by the Code Official if exigent circumstances warrant.
(4)
Following the issuance of a certificate of completion, and provided
that as a minimum 90% of the proposed homes are constructed, the developer's
completion guarantee bond will be released by the Township.
J.
During any stage of the regulated earth disturbance activities, if
the Township or its designee determines that any BMPs are not being
implemented in accordance with this chapter, the Township may suspend
or revoke any existing permits or other approvals until the deficiencies
are corrected.
A.
No regulated development activities within the Township shall commence
until approval by the Township and the WCD of an erosion and sediment
control plan for construction activities.
B.
Any earth disturbance activity of 5,000 square feet or more requires
an erosion and sedimentation control plan under 25 Pa. Code § 102.4(b).
Refer to the PA DEP Erosion and Sediment Pollution Control Manual
2012 or the most recent version of same.
C.
In addition, under Title 25 Pa. Code Chapter 92, a DEP NPDES construction
activities permit is required for regulated development activities.
D.
Evidence of any necessary permit(s) for regulated development activities from the appropriate DEP regional office or Westmoreland Conservation District must be provided to the Township. The issuance of an NPDES construction permit (or permit coverage under the Statewide General Permit (PAG-2)) may be found to satisfy the requirements under Subsection A above conditioned upon review and approval by the Township.
E.
A copy of the erosion and sediment control plan and any permit required
by DEP or the Township shall be available at the project site at all
times.
A.
No regulated development activities which require a Chapter 105 (Water
Obstructions and Encroachment) permit from either PA DEP or the Westmoreland
Conservation District shall commence until all permits, PA DEP or
WCD approval, and Township approval have been received.
B.
Evidence of any necessary Chapter 105 permit from PA DEP/WCD shall
be provided to the Township.
C.
Any proposed development shall avoid the long and short term adverse
impacts associated with the occupancy and modification of floodplains
as designated by FEMA, to the extent possible wherever there is a
practicable alternative to reduce the risk of flood loss, minimize
the impacts of floods on human safety, health and welfare, and restore
and preserve the natural and beneficial values served by floodplains.
D.
Any proposed development found to be within the base floodplain of a waterway shall be in compliance with Chapter 57, Floodplain Management, of the Unity Township Code, and shall include the identification of impacts, an evaluation of practicable alternatives outside the floodplain, and, when impacts cannot be avoided, the development of measures to minimize the impacts and restore and preserve the floodplain as appropriate.
E.
Any proposed stormwater management plan should be consistent with
the provisions of the PA Flood Plain Management Act 166 of 1978, 32
P.S. § 679.101 et seq., and applicable municipal floodplain
ordinances, and when impacts cannot be avoided, the development of
measures to minimize the impacts and restore and preserve the floodplain
is appropriate.