A.
Intent of design and improvement standards. This Article VIII includes specific standards for the design of subdivisions and land developments and requirements for improvements. The standards specified in this article are minimum design and improvement requirements. The Borough will consider alternatives to specific standards and requirements specified herein if the applicant demonstrates that an alternative will achieve the desired outcome to a higher degree or will produce more desirable results than the application of a specified standard.
B.
Site analysis. The design of a subdivision or land development shall
be based upon an analysis of existing conditions of the site, which
includes consideration of the site's natural and man-made features
and of the opportunities and constraints for development that are
associated with these features. The site analysis also shall consider
the relationship of the site to the surrounding developed and undeveloped
areas and to applicable county and regional plans. The applicant's
project narrative, which must be submitted as part of the proposed
subdivision or land development, should summarize how the analysis
of existing conditions has influenced the design of the subdivision
or land development.
C.
Alternative development plan. Before considering requests for waivers or modifications of standards or requirements in this Article VIII that will reduce the attainment of the goals listed in § 360-77, the Borough may require the applicant to prepare alternative development plans which more nearly meet the requirements of this article. Such alternatives may include the clustering of development on portions of the site which are not constrained by the environmental protection provisions of this article and may include a reduction in the otherwise allowable density or intensity of development on the total site. The original plan will be approved only if the applicant demonstrates to the satisfaction of the Borough that an alternative plan is not practical or feasible.
D.
Regulations of other jurisdictions. It shall be the responsibility
of the applicant for approval of a subdivision and land development
to obtain all required permits and approvals from other jurisdictions
or agencies. No application shall be finally approved by the Borough
or recorded until all required permits and approvals have been obtained,
unless the plan for recording includes a notation that specified permits
will be required prior to issuance of construction permits.
E.
Review by Borough Engineer. In reviewing any application for approval
of a subdivision or land development, Borough Council shall refer
the application for development to the Borough Engineer for a recommendation
concerning technical compliance with these design standards and the
Borough construction standards.
Subdivisions and land developments shall be designed to achieve
the general goals or outcomes that are listed in this section.
A.
Minimize damage to the environment. All subdivisions and land developments
shall be designed to minimize environmental damage to the maximum
extent possible by carefully fitting the subdivision or development
to the existing conditions and natural features of the site. Some
of the methods to achieve this goal shall include but not be limited
to the following:
(1)
Minimize grading. Roads, building sites and lots should be laid out
in a manner that will minimize disturbance of the land. Roads should
generally follow existing contours, where doing so will minimize cuts
and fills. Naturally level areas should in general be utilized for
building sites. Clustering of development on less steep areas of the
site is strongly encouraged, as an alterative to mass grading.
(2)
Protect steep slopes. Development should be located to avoid disturbance
of steeply sloped areas and to preserve the visual character of wooded
hillsides.
(3)
Protect watercourses and wetlands. Watercourses are the natural drainage
ways for the conveyance of surface waters, including runoff and floodwaters.
Wetlands provide a habitat for aquatic and terrestrial plants and
animals and may function as wildlife corridors. Development should
be designed to preserve and protect watercourses and wetlands so that
they can continue to serve all of these functions.
(4)
Preserve woodlands and mature trees. New developments should be designed
to preserve and protect existing woodlands, as excessive cutting of
trees and clearance of woodlands in conjunction with subdivision and
land development causes soil erosion, increased runoff, loss of habitat,
and diminution of a significant visual resource: the wooded hillsides
that are a prominent feature in the Borough. The cutting of mature
trees and clearance of woodland shall commence only after final approval
of a plan for subdivision or land development, and then only to the
extent required for the construction of roads, utilities and buildings.
(5)
Protect other identified natural resources. Special care should be
taken in the design and construction of subdivisions and land developments
to protect habitats in which rare or endangered plants or animals
are found and other ecologically important sites.
(6)
Protect historic, architectural and archeological resources. Sites
containing structures of historical or architectural significance
should be designed to preserve, enhance or reuse such structures,
in accordance with any applicable state regulations.
(7)
Protect the quality of air and water. All land development shall
fully comply with federal, state and county laws and regulations concerning
air and water pollution.
B.
Avoid hazardous development. Where hazardous or potentially hazardous
features are present on proposed development sites, the design of
subdivisions and land developments shall consider such features. Appropriate
precautions shall be taken to ensure that development will be safe
and that the public health and welfare will be protected. Development
will not be approved unless safety is ensured by undertaking protective
measures. Such protective measures shall include, but not be limited
to, the following:
(1)
Landslide-prone areas. In areas where soils or underlying geology
may be unstable, geotechnical investigation shall be required to ensure
the safety of any proposed disturbance.
(2)
Undermined areas. In areas where mining has occurred in the past,
subsidence risk assessments may be required to establish that the
proposed development will be safe.
(3)
Flood-prone areas. New construction in the undeveloped one-hundred-year
floodplain should be avoided. New construction in other undeveloped
areas subject to frequent flooding should also be avoided. In areas
where the floodplain has been developed in the past and new construction
is unavoidable, such development shall be in accordance with all applicable
state and federal regulations.
(4)
Contaminated sites. In order to protect the public health, no subdivision
or development of land in areas which may have been contaminated by
former industrial or other uses shall be approved unless the site
has been made safe for development. Development of contaminated sites
shall be limited to uses which will not pose health risks for site
occupants.
C.
General layout considerations. The general layout of subdivisions
and land development should respect the natural resources of the site,
the character of the surrounding area, and be suitable for the intended
uses. The design of block and lots shall comply with applicable zoning
requirements of the Borough and should provide suitable sites for
buildings. The design of subdivisions and land development should
consider the topography and other natural features of the site, requirements
for safe and convenient pedestrian and vehicular circulation and the
character of surrounding development. Subdivisions and land developments
should be compatible with Borough ordinances and with county and regional
Comprehensive Plans.
D.
Landscaping. Land development shall include landscaping which is
designed to improve community appearance, to contribute to the environmental
quality and livability of new development areas and to mitigate the
negative impacts of development upon other areas of the community.
Uses and structures should be sited to minimize adverse impacts from
or upon adjoining uses. Landscaping and buffer yards should be designed
to reduce unavoidable impacts and to augment the natural features
of the site.
E.
Improvements must benefit public health and safety. Subdivisions
and land developments with the Borough should provide a range of improvements
to ensure the public health, safety and welfare. Such improvements
shall include, but not be limited to, the following:
(1)
Water. A safe and sufficient supply of potable water shall be provided
for new subdivisions in accordance with applicable state and county
regulations. New development should not degrade the existing quality
of potable water supplies in the Borough.
(2)
Sanitary facilities. Sanitary facilities shall be provided for new
subdivisions and land developments in accordance with applicable state
and county regulations.
(3)
Stormwater management. Every subdivision and land development shall
manage stormwater flows in accordance with the Pennsylvania Storm
Water Management Act[1] and county and Borough ordinances/regulations. All development
in watersheds for which watershed stormwater management plans have
been adopted shall comply with all requirements of the watershed plan.
[1]
Editor's Note: See 32 P.S. § 680.1 et seq.
(4)
Other essential public utilities. New subdivisions and land developments
shall be served by other essential public utilities, including electricity,
natural gas and telephone. New subdivisions and land development also
may be served by alterative energy sources, such as solar or wind,
in accordance with other applicable state and federal regulations.
(5)
Public and community services. All new development should have access
to a full range of community services and facilities, such as public
safety and emergency services, recreation facilities and schools.
(6)
Transportation facilities. New subdivisions and land developments
should include a range of transportation facilities, for access to
all lots, buildings, and open space areas intended for use by people.
Transportation facilities developed within new subdivisions and land
developments should be designed as parts of the larger system of transportation
facilities which serve the Borough. Transportation facilities may
include streets, public transportation, sidewalks, bikeways and multipurpose
trails for nonmotorized transportation.
A.
Concrete monuments shall be set at the intersection of all lines
forming angles in the boundary of the subdivision. Three-eighths inch
standard iron or steel markers shall be set at the beginning and ending
of all curves along street property lines; at all points where lot
lines intersect curves, either front or rear; at all angles in property
lines of lots and at all other lot corners.
B.
In minor subdivisions, Borough Council, upon recommendation of the
Borough Engineer, may waive the requirement for the number of monuments.
C.
The installation and certification shall be made by a registered
surveyor prior to final approval of the subdivision. In lieu of such
prior installation, the applicant shall furnish a cash deposit in
the form of a certified check to guarantee the proper installation
of the required monuments and bench marks. The refundable deposit
shall be in an amount established from time to time by resolution
of Borough Council.
D.
The location and tie-in dimensions of all monuments shall be shown
on the plan for recording. No public improvements shall be accepted
by the Borough until all monuments have been set and certified to
by a registered surveyor.
A.
Each lot shall be served by public water and the developer shall
be responsible for obtaining all necessary approvals and entering
into an agreement with the water company servicing the area or its
assigns to provide such facilities in accordance with its rules and
regulations.
B.
Sanitary sewers, storm sewers and drainage facilities shall be provided by the developer in each plan and shall be constructed in accordance with the design standards of this article and the Borough construction standards. If required by § 360-88 of this chapter, stormwater management facilities shall be constructed in accordance with the Borough's requirements.
C.
The developer shall be responsible for contracting with private utility
companies and for providing any easements required by those utility
companies to guarantee that each lot shall be served by telephone,
gas and/or electricity and cable TV.
D.
The location and type of fire hydrants shall be subject to the review
and approval by the Borough Fire Marshal or Fire Chief.
A.
In all subdivisions and land developments, sidewalks shall be required
to be installed along the full frontage of all lots under the following
circumstances:
(1)
In all major subdivisions;
(2)
In all minor subdivisions and land developments where sidewalks exist
in the same block on the same side of the street;
(3)
On all lots with frontage on arterial or collector streets, as defined
by this chapter;
(4)
Within a land development plan proposed to be developed for more
than 25 multifamily dwelling units to accommodate pedestrian circulation
between buildings and parking areas and other common facilities; and
(5)
Within a land development plan proposed to be developed for office
or commercial use to accommodate pedestrian circulation between buildings
and parking areas and other common facilities.
B.
Sidewalks shall be installed in accordance with the design standards
of this article of this chapter and the Borough construction standards.
The width of sidewalks shall conform to the standards specified in
Appendix II.[1] Sidewalks shall be located in line with existing sidewalks
on adjacent lots or, where none exists, shall be located a minimum
of two feet from the edge of any curb or paving where practical. The
grade and paving of the sidewalk shall be continuous across driveways.
Concrete sidewalks shall be four inches reinforced, except at driveway
crossings where the thickness shall be increased to six inches and
be reinforced with six inches by six inches mesh, No. 9 gauge. All
sidewalks shall be constructed in accordance with the Borough construction
standards.
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.
A.
The developer shall prepare a streetlighting plan for submission
to the power company providing service to the area. For the safety
and convenience of the public, the developer shall furnish and install
streetlights at his/her cost which are approved by the Borough and
the power company on poles prescribed by the Borough on all public
and private streets.
B.
The Borough shall indicate to the power company its willingness to
accept billing for the operation of the streetlights following installation
by the developer.
C.
On all arterial and collector streets and at intersections of local
streets and at other locations where the Borough Council, upon recommendation
of the Borough Engineer, determines streetlighting is necessary for
public safety, streetlights shall be installed in accordance with
the specifications of the regulatory agency, subject to approval by
the Borough.
The developer shall provide street name signs and traffic control
signs, approved by the Borough, at all street intersections. The cost
of the street signs and posts shall be assumed by the developer. Street
signs shall be designed in accordance with the Borough construction
standards and shall be installed and maintained by the Borough.
A.
Grading, filling, removal of topsoil, erosion and sedimentation control.
All grading, filling, removal of topsoil and erosion and sedimentation
control shall be performed in accordance with all requirements for
grading and excavating enacted by the Borough and the requirements
of the Pennsylvania Clean Streams Law[1] and Ordinance 102 of the Rules and Regulations of the
Pennsylvania Department of Environmental Protection governing erosion
control.
[1]
Editor's Note: See 35 P.S. § 691.1 et seq.
B.
Planting and cutting of trees; removal of debris.
(1)
Large shade trees shall be adequately protected from injury and preserved
to the extent practical.
(2)
All lot areas which slope towards streets or adjacent lots shall
be required to be seeded with grass or planted with ground cover so
as to prevent washing and erosion.
(3)
During construction, the developer shall remove and dispose of all
uprooted trees, stumps, brush, rubbish, unused building materials
and debris promptly in the interest of public safety.
C.
Flood-prone areas. Land identified as flood-prone on maps issued
by the Federal Insurance and Mitigation Administration shall be subject
to the regulations of the National Flood Insurance Program and shall
comply with the any floodplain regulations adopted by the Borough
pursuant to ordinance.
A.
Frontage. Each lot shall have frontage on a public street, as defined by this chapter, unless an exception or modification to this requirement is granted in accordance with the provisions of Article IX of this chapter.
B.
Layout. Streets shall be planned to conform to the layout of existing and planned streets and so located as to allow proper development of surrounding properties. Local streets shall be laid out so as to discourage through traffic. Collector streets shall be designed to provide adequate flow of traffic from local streets to major community facilities and to arterial streets. Intersections of more than two streets at one point shall not be permitted. Dead end streets shall not be permitted, unless the requirements of Subsections E and F of this section are met. Half streets shall not be permitted.
C.
Topography. Proposed streets shall be planned to conform to the contour
of the land, to the fullest extent possible to provide buildable lots,
to have a suitable alignment and grade and to allow proper drainage.
D.
Street grades. Minimum and maximum grades shall be provided on all
streets in accordance with the design standards specified in Appendix
II. Grades shall be measured along the center line of the street.
Vertical curves shall be used in changes of grade exceeding 1% and
shall be designed in accordance with the design standards specified
in Appendix II.[1] Intersections shall be approached on all sides by leveling
grades for a distance of 50 feet within which no grades shall exceed
the design standards specified in Appendix II. The grade of actual
intersections shall not exceed 6% in any direction.
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.
E.
Right-of-way and paving widths; curbs; shoulders.
(1)
Minimum widths of rights-of-way and minimum widths of paving shall
be provided in accordance with the design standards specified in Appendix
II. All streets shall be paved in accordance with the Borough construction
standards.
(2)
Curbs shall be provided on all streets in accordance with the design
standards specified in Appendix II and the Borough construction standards.
(3)
Street shoulders shall be constructed which are uniformly and thoroughly
compacted by rolling and which are level with the tops of curbs.
F.
Culs-de-sac.
(1)
A cul-de-sac street shall not be approved when a through street is practical and shall not be more than 800 feet in length, unless an intermediate turnaround is provided at a distance of every 800 feet and a modification or exception to the maximum 800-foot length of cul-de-sac is granted in accordance with the requirements of Article IX of this chapter. The length of a cul-de-sac street shall be measured from the point of intersection of the center lines of the two intersecting streets to the back of the curb of the cul-de-sac turnaround.
(2)
A cul-de-sac shall have a minimum right-of-way radius and an outer
minimum paving radius as specified in the design standards in Appendix
II. The maximum grade of the turnaround portion of the cul-de-sac
shall be 5%.
G.
Temporary turnarounds. A temporary turnaround may be required where
a road is constructed to an adjoining property line or where the terminus
of a road adjoins property in a future phase of the plan. The temporary
turnaround shall be paved. The right-of-way width required for a temporary
turnaround shall be a minimum of 100 feet and the paving radius of
the temporary turnaround shall be 40 feet, exclusive of the required
curb.
H.
Visibility.
(1)
No fence, hedges, shrubbery, walls, planting (other than trees and grass) or similar obstructions shall be located within the right-of-way and no such obstruction shall obscure visibility at any intersection. The location of fences and walls shall be further subject to the requirements of Chapter 440, Zoning.
(2)
A clear sight triangle, as defined by this chapter, shall be maintained
free of any obstructions at intersections so that there shall be a
minimum clear sight triangle measured along the center line from the
points of intersection in accordance with the requirements specified
in Appendix I. The clear sight triangle shall be shown on the final
plat for recording.
I.
Street names. All new street names shall be approved by the Borough and the post office. Names of new streets shall be sufficiently different in sound and spelling from existing names of streets in the Borough or in the 911 service area so as not to cause confusion. A street which is planned as a continuation of an existing street shall bear the same name. Street signs shall be provided in accordance with § 360-82 of this chapter.
J.
Crosswalks. Crosswalks may be required wherever necessary to facilitate
pedestrian circulation and to give access to community facilities
such as parks, playgrounds, schools or public buildings.
Service streets, as defined by this chapter, may be permitted
in commercial and industrial developments where needed for loading,
unloading or secondary access. Service streets shall be constructed
in accordance with Borough construction standards and shall meet the
minimum design standards shown in Appendix I[1] for local streets, except that the minimum right-of-way
width may be reduced to 30 feet and the minimum cartway width may
be reduced to 20 feet.
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.
Easements for sanitary sewers, water lines and stormwater management
facilities shall be required to have a minimum width of 20 feet. Where
a subdivision or land development is, or will be, traversed by a watercourse,
there shall be provided a stormwater easement or drainage right-of-way
of a width sufficient for the purpose, but not less than 20 feet.
The following standards shall apply to all lots proposed to
be subdivided or developed in accordance with this chapter.
A.
Area.
(2)
When a tract is subdivided into lots that are larger than the minimum lot area required by Chapter 440, Zoning, such lots or parcels shall be so arranged as to permit a logical location and opening of future streets and resubdividing with provisions for adequate utility connections for each subdivision.
B.
Frontage. All lots created by a subdivision shall have frontage along the right-of-way of a public street and the width of the frontage shall conform to the requirements of Chapter 440, Zoning. Every lot shall be accessible to emergency service, public safety and firefighting vehicles and equipment.
C.
Double frontage. Double frontage lots shall be avoided; however,
where a double frontage lot is the only practical alternative, vehicular
access shall be limited to only one street and that street shall be
the street with the lower volume of traffic, if physically feasible.
The final plan shall contain a notation restricting vehicular access
to one street frontage.
D.
Side lines. Whenever practical, the side lines of a lot shall be
at right angles or radial to the right-of-way lines of streets.
E.
Front building lines. Front building lines of lots shall conform to the minimum requirements of Chapter 440, Zoning, and shall be shown on the final plat.
F.
Grading of lots. Lots shall be graded to provide drainage away from
buildings and water shall be drained to the street, rather than to
adjoining property. The developer shall be required to provide drains
or other drainage facilities, as approved by the Borough Engineer,
to drain off surface water within the development. All grading shall
comply with the all requirements for grading and excavating enacted
by the Borough.
G.
Driveways.
(1)
No driveway shall have a slope of more than 12%. Driveways may extend
from the right-of-way line of the street to the cartway of the street,
but shall not change the grade or contour of the street right-of-way,
nor shall any person cut into, fill, or in any way alter any gutter,
curbing, drainage ditch or storm sewer, within the right-of-way of
a street or easement for the purpose of extending a driveway; or for
any other purpose without first obtaining a permit therefor from the
Borough. All curb cuts shall conform to Borough specifications. Paved
driveways shall have a joint at the public street right-of-way. Driveways
shall not be constructed in such a way that creates a drainage problem
on adjoining property. No catch basin shall be placed where a driveway
intersects a street.
(2)
Driveways intersecting Borough streets shall have an improved surface
with a minimum thickness of four inches bituminous concrete or six
inches cement concrete. Driveways intersecting state roads shall be
constructed in accordance with the Pennsylvania Department of Transportation
Design Manual, Part 2, Ordinance 18. Driveways intersecting county
roads shall be subject to a permit from the Allegheny County Department
of Public Works.
(3)
Driveways which are shared among two or more lots shall have a minimum
improved surface 12 feet in width. Common driveways shall be within
a recorded easement at least 15 feet in width and shall be subject
to a recorded agreement for maintenance which is noted on the plat
and referenced in the deeds for each lot the driveway serves.
H.
Accessibility. Every lot, building and structure shall be accessible
to emergency and public safety vehicles.
I.
House numbers. House numbers shall be assigned by the developer,
subject to the approval of the U. S. Postal Service. House numbers
shall be posted at each house so as to be readable from the street
and shall be comprised of Arabic numerals or alphabet letters at least
four inches high with a minimum width stroke of 1/2 inch and of contrasting
color.
[Amended at time of adoption of Code (see Ch. 1, General
Provisions, Art. I)]
Stormwater management facilities shall be provided for subdivisions and land developments and shall satisfy the requirements set forth in the Allegheny County Stormwater Management Plan and in Chapter 347, Stormwater Management, of the Code of the Borough of Whitaker. In general, stormwater management facilities shall be designed to ensure that the maximum rate of stormwater runoff from the site shall be no greater after development than is the rate of runoff from the site prior to development.
A.
Design calculations and reports.
(1)
Stormwater runoff and design calculations shall be submitted to the
Borough Engineer for review and approval with the application for
combined preliminary and final approval of a land development plan.
Cross sections and specifications showing complete construction details
shall be submitted with the application for final approval.
(2)
The stormwater runoff and design calculations shall be prepared by
a Pennsylvania registered engineer with qualifications and experience
in preparing stormwater management plans.
(3)
Additional analysis, calculations and design criteria shall be required
for both on-site and off-site stormwater systems where it has been
determined by the Borough Engineer that further study is necessary.
(4)
Stormwater runoff calculations shall be provided for: the outlet
and inlet sides of all stormwater drainage and storage facilities
and structures; at points in a public street with a change of grade;
or where water from a proposed structure, facility or vehicular way
is to enter an existing public street, existing storm sewer, existing
drainage ditch or existing stormwater storage facility.
B.
Exemptions for small developments.
(1)
At the time of application, the Borough Engineer shall determine
if the development qualifies as a "small development" and, therefore,
is eligible for a simplified stormwater plan submission. For the purposes
of this chapter, a small development is:
(a)
Any development which results (or will result when fully constructed)
in the creation of 5,000 square feet or less of impervious surface
area.
(2)
A small development shall be exempt from the preparation of a stormwater management plan as required by § 360-88C of this chapter. However, such developments shall provide safe management of stormwater management in accordance with the performance standards of this chapter and as approved by the Borough Engineer.
(3)
Applications for small developments shall include a plan which describes,
narratively and graphically, the type and location of proposed on-site
stormwater management techniques or the proposed connection to an
existing storm sewer system. The plan shall be prepared by a registered
professional engineer.
(4)
The Borough Engineer shall review and approve the proposed provisions
for stormwater management for small developments. Where the applicant
is proposing to connect to an existing storm sewer, the applicant's
engineer shall determine that sufficient capacity exists in the storm
sewer from the point of connection to the point of outlet in the natural
drainage system. The applicant's engineer shall also determine if
the proposed development site is part of a larger parcel or tract
which was subject to any specific stormwater management controls contained
in a prior plan.
(5)
For a parcel or tract of land held in single ownership, only one
application for a small development, as defined above, shall be permitted
before requiring a stormwater management plan for the entire parcel.
C.
Stormwater plan content. The stormwater management plan for all developments except small developments, as defined in Subsection B, shall consist of the following three components:
(1)
Narrative report. The narrative report shall consist of a general
statement of the project giving the purpose and engineering assumptions
and calculations for control measures and facilities. The following
information shall be included.
(a)
General description of the project.
(b)
General description of accelerated runoff control plan.
(c)
General description of erosion and sedimentation control plan.
(d)
Expected project time schedule, including anticipated start
and completion dates.
(e)
Location and watershed characteristics.
(f)
Hydraulic and hydrologic calculations, methodology and basis
of design.
(g)
Brief soils description.
(2)
Preliminary plan. The preliminary plan shall provide, and be accompanied
by, maps and other descriptive material indicating the feasibility
of the plan and showing the following:
(a)
A key map showing the development site's location within the
designated watershed and watershed subsheds (consult watershed stormwater
plans for boundaries). On all site drawings, show the boundaries of
the watershed(s) and subarea(s) as they are located on the development
site and identify the watershed names and/or subshed numbers.
(b)
Location of the 100-year floodplain on the development site
based on the Whitaker Borough Flood Insurance Study Maps or a determination
by the applicant's engineer.
(c)
An overlay showing soil types and boundaries within the development
site.
(d)
The streets, storm sewers and other storm drains to be built,
the basis of their design, the outfall and outlet locations and elevations,
the receiving stream or channel and its high water elevation and the
functioning of the drains during high water conditions.
(e)
The parts of the proposed parking area pavements, if any, which
are planned to be depressed to provide stormwater storage or conveyance.
A maximum of six inches depth of water may be ponded in a proposed
parking area.
(f)
Existing streams and watercourses to be maintained and new channels
to be constructed, their locations, cross-sections and profiles.
(g)
Proposed culverts and bridges to be built, if any, their materials,
elevations, waterway openings and basis of design.
(h)
Existing detention ponds and basins to be maintained, enlarged
or otherwise altered and new ponds or basins to be built and the basis
of their design.
(i)
The approximate location and percentage of the total land area
in the development which will be covered by impervious surfaces after
construction is completed.
(j)
The slope, type and size of all proposed and existing storm
sewers and other waterways.
(k)
Existing contours at intervals of two feet except in areas with
slopes greater than 10% in which case five-foot contour intervals
may be used.
(l)
All natural features, including bodies of water (natural and
artificial), watercourses (permanent and intermittent), swales, wetlands
and other natural drainage courses on the development site and those
off-site which will be affected by runoff from the development.
(m)
Approximate depth, shape, size and storage of any proposed retention
facility.
(n)
One or more typical cross-sections of all existing and proposed
channels or other open drainage facilities, showing the elevation
of the existing land and the proposed changes thereto, together with
the high water elevations expected from the one-hundred-year storm
under the controlled conditions called for by this chapter and the
relationship of structures, streets and other utilities.
(o)
A site plan showing the property lines, dimensions of the site
and location of existing and proposed structures, sewers, waterlines,
easements and rights-of-way.
(p)
Certification of the registered professional engineer responsible
for preparation of the plan.
(q)
A list of the permits and approvals relative to stormwater management
that will be required from other governmental agencies and anticipated
dates of submission and receipt. Copies of the applications may be
requested by the Borough Engineer where they may be helpful for the
stormwater plan review.
(3)
Final plan. Upon approval of the preliminary plan, the final plan
shall be submitted to the Borough. The final plan shall provide all
descriptive material and maps previously submitted and required prior
to the final plan, in addition to the following items:
(a)
All calculations, assumptions and criteria used in the design
of the storm sewer system, detention facilities and sediment and erosion
control operations. Hydraulic and energy grade lines shall be provided
for proposed storm sewers.
(b)
All plans and profiles of proposed storm sewers and open channels,
including horizontal and vertical controls, elevations, sizes, slopes
and materials.
(c)
Locations, dimensions and design details required for the construction
of all facilities.
(d)
For all detention basins, a plot or tabulation of storage volumes
with corresponding water surface elevations and basin outflow rates
for those water surface elevations.
(e)
For all detention basins, design hydrographs of inflow and outflow
for the peak design flows from the site under natural and developed
conditions.
(f)
A description of operation for all detention basins.
(g)
Contours of the finished project site at intervals of two feet,
except in areas with slopes greater than 10%, in which case, five-foot
contour intervals may be used.
(h)
The staging of earthmoving activities and program of operation,
including a schedule for the installation of all temporary and permanent
stormwater control measures and devices.
(i)
All information relative to the design and operation of emergency
spillways.
(j)
Emergency routing of outfall for stormwater runoff in the event
of failure of off-site drainage structures.
(k)
When major control facilities, such as retention basins, requiring
a PA DEP permit, are planned, soil structures and characteristics
shall be investigated. Plans and data prepared by a licensed professional
engineer or geologist with experience and education in soil mechanics
shall be submitted. These submissions should consider and offer design
solutions for frost heave potential, shrink/swell potential, soil
bearing strength, water infiltration, soil settling characteristics,
fill and backfilling procedures and soil treatment techniques as required
to protect the improvements or structures.
(l)
All erosion and sedimentation control measures, temporary, as
well as permanent, in sufficient detail to clearly indicate the effectiveness
of the plan.
(m)
Project specifications relative to stormwater control, erosion
and sedimentation.
(4)
Maintenance plan. A maintenance plan establishing ownership and maintenance
responsibilities for all stormwater control facilities (identifying
the specific person or entity responsible) and detailing financial
requirements and sources of funding shall be submitted with the final
plan. Any legal agreements or covenants required to implement the
maintenance program shall be submitted. A maintenance schedule shall
be submitted in accordance with the Standardized Maintenance Schedule
in Appendix III.[1]
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.
D.
General standards. The following provisions shall be considered the
overriding performance standards against which all proposed stormwater
control measures shall be evaluated:
(1)
Health and safety measures. 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 and other property.
Such measures shall include, but not be limited to, such actions as
are required to:
(2)
Design storms.
(a)
Stormwater management facilities within a development shall
be designed to handle the peak rate of runoff from two-, five-, ten-,
twenty-five- and 100-year frequency storm events. Whenever the provisions
of federal or state law impose a greater design storm frequency (as
for example, where drainage systems cross highways), the stricter
standards shall prevail.
(b)
All stormwater retention/detention facilities shall be designed
with emergency overflow facilities for the 100-year, twenty-four-hour
duration storm.
(c)
The stormwater volume required for all stormwater retention/detention
facilities shall be that volume necessary to handle runoff of a 100-year
storm in any development, less that volume discharged during the same
storm period used to calculate the volume of rainfall, at the approved
release rate.
(d)
The NRCS, Type II Rainfall Distribution shall be used for all
analyses. The design storm frequencies for the watershed are:
|
Design Storm
|
Rainfall Depth 24 Hours
(inches)
|
|---|---|
|
2 year
|
2.6
|
|
5 year
|
3.3
|
|
10 year
|
3.8
|
|
25 year
|
4.4
|
|
100 year
|
5.0
|
(3)
The stormwater management plan shall consider all of the stormwater
runoff flowing over the project site. Runoff calculations shall be
made to insure that runoff from the fully developed upstream watershed
area (based on the Borough's Comprehensive Land Use Plan) can be accommodated
by the pipes, drainage easements and watercourses, etc., on the site.
(4)
Joint development of control systems. Stormwater control systems
may be planned and constructed in coordination with two or more developments,
provided they are in compliance with the applicable provisions of
this chapter.
(5)
Method of computation.
(a)
All computations used in conjunction with the analysis and design
of stormwater management facilities shall be based on one or more
of the following methods:
(c)
These methods of runoff computation developed and used by the
Natural Resources Conservation Service and other authorities are hereby
adopted by the Borough.
(d)
The use of the Basic Rational Method in estimating runoff may
be employed in the design of the storm sewer system within the development.
The storm sewer system shall be interpreted as the conduits, culverts,
inlets and appurtenant features for the conveying of stormwater to,
through or from a development site to the point of final discharge
or control facility. The Rational Method shall not be used in the
analysis of stormwater runoff from the development in its entirety
or in conjunction with the design of any retention/detention facilities
or other runoff control measures.
(6)
Release of detained stormwater. The approved peak release rate of
stormwater from all retention/detention facilities for any storm event
shall be that which is experienced prior to development for the same
storm event up to and including the 100-year storm. Therefore, all
retention/detention facilities shall provide staged release of the
two-, five-, ten-, twenty-five- and 100-year storms.
(7)
Design of stormwater management facilities outlined in the plan requires
that runoff calculations be made for the site and areas which contribute
drainage to the site. These calculations should be based on land use,
time of concentration and other standard aspects of hydraulic analysis.
(a)
Temporary control measures/facilities. Runoff calculations of
the site's condition during development will be used to size temporary
control measures.
(b)
Permanent control measures/facilities. In most cases, permanent
control measures/facilities shall be designed to assure that the maximum
rate of stormwater runoff is no greater after development than prior
to development activities, utilizing the 100-year storm as a basis
for calculations.
(8)
Runoff calculations shall also include complete hydrology and hydraulic
analysis of all erosion control facilities, including, but not limited
to:
(9)
Single-family lots.
(a)
Retention facilities shall be constructed for any proposed single-family
lot developments or single-family lots located in a subdivision or
land development which for terrain reasons cannot utilize the subdivision
or land development's retention systems. Retention facilities shall
consist of gravel filled sumps, ponds, tanks or other approved facilities,
sized in accordance with standard details in the Borough construction
standards. Refer to Figures SWM 6, 6-A and 7 for minimum volume size
per single residence roof area.
(b)
Storage volumes for roof areas greater than 5,000 square feet shall be calculated using the methods outlined in § 360-88D(5).
(c)
All stormwater retention facilities shall be located at least
10 feet from foundation walls in a location approved by the Building
Inspector. All pipe from roof drains to a point 10 feet from the structure
shall be a minimum Schedule 40 PVC pipe or approved equal.
E.
Construction criteria for stormwater control facilities. Stormwater
management facilities shall be constructed in accordance with the
following minimum specifications:
(1)
All workmanship and materials shall conform to the Borough construction
standards. In addition, all workmanship and materials shall conform
to the latest edition of Penn DOT Form 408.
(2)
All connections to existing storm sewer pipes shall be made by construction
of a suitable junction box (inlet or manhole) to provide access for
cleanout. No blind connections shall be permitted.
(3)
All pond outlet structure pipes shall have suitable gaskets to prevent
leakage and piping of water through the pond embankment.
(4)
All pipe outlets shall discharge onto a stone riprap blanket to prevent
erosion of soil. Riprap will be sized considering pipe exit velocities.
(5)
Controls shall be installed at initial stages of earthmoving and
otherwise as outlined in the staging of earthmoving activities section
of the erosion and sedimentation control plan.
(6)
The discharge of stormwater runoff shall be to a well-defined drainage
course which has a defined bed and bank. If stormwater runoff cannot
be discharged to a defined drainage course, documentation of written
permission from each downstream landowner shall be provided for all
properties between the source of discharge and the defined drainage
course.
(7)
All stormwater detention facilities shall be enclosed by a fence
which is a minimum of six feet in height with a locking gate of sufficient
width to provide access for maintenance vehicles.
(8)
All storm sewers shall be laid with a full moon, to line and grade
with no horizontal or vertical deflection.
(9)
The minimum pipe size shall be 15 inches.
(10)
The minimum pipe slope shall be 1%.
(11)
The minimum cleansing velocity shall be 2.0 feet per second.
F.
Maintenance criteria for stormwater control facilities. Maintenance
is an essential part of the successful functioning of a stormwater
management system and the following shall be required:
(1)
Maintenance during development. Maintenance during development of
a project shall be the responsibility of the developer and/or landowner
and shall usually include, but shall not be limited to:
(a)
Removal of silt from all debris basins, traps or other structures
or measures when 40% of capacity is filled with silt.
(b)
Disposal of collected silt in a manner which will not adversely
affect the environment.
(c)
Periodic maintenance of temporary control facilities such as
replacement of straw bale dikes, straw filters or similar measures.
(d)
Establishment or reestablishment of vegetation by seeding and
mulching or sodding of scoured areas where vegetation has not been
successfully established. A developer or landowner retains this obligation
as to property he or she has developed or improved even if the proper
season for "seeding" occurs initially sometime after the project is
otherwise completed in whole or as to a particular phase.
(e)
Installation of necessary controls sufficient to protect against
problems caused by storm events within design frequencies.
(f)
Removal of all temporary measures upon completion of the project.
(2)
After acceptance of the plan by the Borough. In the event that the
Borough accepts public improvements in the plan, except in cases where
an agreement between the developer and the Borough has been executed
to the contrary, the maintenance shall be the responsibility of the
landowner and shall include, where necessary:
(a)
Mowing to maintain adequate stands of grass and to control weeds.
Chemical weed control may be used if state and Borough regulations
are met. Selection of seed mixtures shall reflect the type specified
in the Borough construction standards.
(b)
Removal of silt from all permanent structures which trap silt
or sediment to keep this material from building up in grassed waterways
and other permanent structures, thereby reducing their capacity.
(3)
It shall be the responsibility of the landowner to inspect all permanent
facilities to see that corrective action is taken where necessary.
(4)
Stormwater facilities located on private property shall be maintained
by the landowner or his agent; however, this does not relieve the
landowner or his agent of the obligation to inspect their own facilities.
The Borough reserves the right to enter upon private property to make
periodic reasonable inspections and to require the landowner to take
necessary corrective actions. An easement shall be recorded granting
access over private property to the stormwater facilities.
G.
Stormwater culverts. Stormwater culverts, bridges and similar structures
serving public streets, access driveways or other vehicular rights-of-way
shall be designed to support HS-20 loading and any other imposed loadings
necessary without structurally damaging the drainage system. Stormwater
culverts, bridges or other structures which do not serve vehicular
traffic shall be designed to support the necessary loading without
structurally damaging the pipe or affecting its capacity for drainage.
Said design shall be approved by the Borough Engineer and shall comply
with the following requirements.
(1)
Conduit size of culverts and other enclosed components of a stormwater
drainage system shall be based on computed hydrologic and hydraulic
data and computations shall be approved by the Borough Engineer. The
minimum size of any enclosed structure to be maintained by the Borough
shall be 15 inches in diameter. The minimum size of any enclosed structure
to be privately maintained shall be 15 inches in diameter, unless
the design calculations, approved by the Borough Engineer, justify
a lesser size.
(2)
The design of any enclosed drainage course shall provide a minimum
cleaning velocity of two feet per second. When the design provides
for a maximum velocity greater than 10 feet per second, the enclosed
components shall be lined or protected to prevent scour.
(3)
The design of headwall and endwall structures for enclosed stormwater
facilities shall be approved by the Borough Engineer and shall be
in accordance with the Borough construction standards.
(4)
Energy dissipaters shall be required at the outlet side of all enclosed
culverts or similar components and shall be designed in accordance
with the Borough construction standards.
(5)
The type of materials used for enclosed culverts and similar components
shall comply with the Borough construction standards. no stormwater
facility shall be enclosed or covered over until the Borough Engineer
has inspected the construction.
H.
Open stormwater drainage courses. Open stormwater drainage courses
shall be designed for a maximum velocity not to exceed 10 feet per
second and a minimum velocity of five feet per second. A minimum velocity
of three feet per second may be authorized by the Borough Engineer
where a greater slope cannot be achieved to permit the standard required
minimum velocity. An open stormwater drainage course shall include
a lining (rip-rap, concrete or bituminous) to prevent erosion. The
applicant shall obtain approval from the Allegheny County Soil Conservation
Service, if required.
A.
Size and grade. Storm drains shall be adequate for the anticipated runoff when the area is fully developed. The minimum diameter of storm sewers shall be 15 inches, and the minimum grade shall be 1%, unless recommended by the Borough Engineer and approved by Borough Council in accordance with the procedure specified in Article IX of this chapter.
B.
Manholes. For all pipe sizes, manholes shall be spaced at a maximum
of 250 feet. In addition, manholes shall be installed at all points
of abrupt changes in horizontal alignment and vertical grade. Inlets
may be substituted for manholes where practical.
C.
Inlets. Inlets of the type shown in the Borough construction standards
shall be installed. Inlets at street intersections shall be placed
on the tangent and not on the curved portions.
D.
Castings. Manholes and inlet castings shall be as indicated in the
Borough construction standards.
E.
Stormwater roof drains.
(1)
All roof drains shall discharge to an on-lot sump or to a storm sewer
system which is controlled by a detention pond. Outlets from roof
drain sumps shall not discharge directly onto fill slopes. Outlets
shall not discharge directly to the gutter line of any street.
(2)
All pipe from roof drains shall be a minimum four-inch Schedule 40
ABS, PVC or SDR 35 pipe. Four-inch Schedule 40 PVC or ABS pipe is
required for a distance of 10 feet from the foundation of the dwelling.
No stormwater drainage system shall be permitted to discharge into
any sanitary sewer system. No pipes shall be permitted to be constructed
through any curbing on any public street.
F.
Unnatural drainage. All points of concentrated flow discharge shall
outlet directly to a well-defined drainage channel. Whenever construction
stops or concentrates the natural flow of storm drainage in such a
way as to affect adjoining properties, approval of the owners shall
be obtained in writing. Approval of plans by the Borough shall not
authorize or sanction drainage affecting adjoining properties.
G.
Watercourses. Open watercourses shall not be permitted within the
rights-of-way of streets. The stopping, filling up, confining or other
interference with, or changing the course of, drains, ditches, streams
and watercourses in the Borough shall not be permitted unless approval
in writing is obtained from Borough Council. A permit shall be obtained
from the Department of Environmental Protection (DEP) of the Commonwealth
of Pennsylvania for construction or changes in a watercourse subject
to the regulations of the Pennsylvania Department of Environmental
Protection.
H.
Bridges and culverts. All bridges and culverts shall be designed
to support expected loads and to carry expected flows and shall be
designed to meet current standards of the Pennsylvania Department
of Transportation. All bridges and culverts shall be subject to all
permits required by the Pennsylvania Department of Environmental Protection,
Bureau of Dams and Encroachments.
A.
Installation. Installation of sanitary sewers and appurtenances shall
be in accordance with the Borough construction standards and the regulations
of the PA Department of Environmental Protection (PA DEP) and subject
to the approval of the Borough Engineer. All utility stubs shall be
extended to the street right-of-way line.
B.
Minimum size and grade. The minimum diameter of sanitary sewers shall
be eight inches and the minimum grade shall be 1%.
C.
Laterals. Lateral connections, where required, shall be installed
to the right-of-way line of the street prior to road paving. Each
building shall have a separate connection to the Borough sewer, except
that garages accessory to dwellings may be connected to the dwelling
line.
The developer shall connect to the public water supply and construct
a system of water mains with a connection for each lot.
In addition to all applicable design standards specified in §§ 360-78 through 360-91 and 360-93 through 360-94, all land developments shall comply with the following design standards:
A.
Lighting of property.
(1)
Parking and pedestrian areas on the property shall be lighted to
create a level of not less than one footcandle when measured three
feet above the pavement throughout the paved areas on the property.
Such lighting may be from freestanding lamp posts within the parking
areas, from nearby streetlights or from lights mounted on buildings.
Lighting shall be shielded or aimed so as not to create glare conditions
on adjacent streets or properties. Lighting shall be designed so that
spillover lighting on adjacent properties shall not occur.
(2)
Light standards in parking areas shall be protected from accidental
damage by vehicles.
B.
Landscaping.
(1)
All areas of the property not paved or occupied by buildings shall
be landscaped and maintained in grass, shrubs, trees, ground cover,
mulching materials or other natural materials planted in accordance
with accepted minimum standards. At least 5% of the total area of
the property shall be set aside for landscaping. Lot areas not covered
by buildings, sidewalks, pavement or other improvements shall be seeded
with grass or other appropriate ground cover material compatible with
the landscape and architectural design and condition of the surrounding
areas. Landscaping materials shall not obstruct sight distances at
access points to the property.
(2)
Where required by Chapter 440, Zoning, buffer areas shall be provided which comply with the design standards specified in Chapter 440, Zoning. A landscaping plan shall be submitted which shows compliance with this chapter, any buffer area requirements and required landscaping and screening of parking areas and loading areas.
C.
Garbage and trash containers. All organic rubbish and discarded materials
shall be placed in tight verminproof containers on the property and
shall be secured in side or rear yards screened from public view by
means of a solid face fence or wall. Containers shall be emptied not
less frequently than once a week. On properties where food is served
in paper containers, covered waste receptacles shall be conspicuously
located on the premises for use by patrons. The management shall be
responsible for maintaining the property free of litter.
D.
Parking areas. Parking areas shall be designed in accordance with the provisions of Chapter 440, Zoning. Ingress and egress and interior circulation on the site shall be designed to ensure safety and minimize congestion. Adequate provision shall be made for safe pedestrian circulation within the parking areas and from the parking areas to the buildings. Fire lanes shall be adequately marked and maintained in locations approved by the Borough.
E.
Incorporation of County Subdivision and Land Development Ordinance standards. All land developments in the Borough shall comply with the design standards set forth in the following sections of the Allegheny County Subdivision and Land Development Ordinance, which are incorporated by reference in their entirety herein and attached to this chapter as Appendix IV:
(1)
Standards for Protection of Steep Slopes in Section 780-24.
(2)
Standards for Protection of Trees and Woodlands in Section 780-26.
(3)
Standards for Protection of Significant Natural Area in Section 780-27.
(4)
Standards for Preservation of Historic, Architectural and Archeological
Resources in Section 780-28.
(5)
Standards for Protection of Air and Water Quality in Section 780-29.
(6)
Standards for Avoidance of Hazardous Development in Section 780-30.
(7)
Standards for Parks, Open Space and Recreation Facilities in Section
780-37.
All subdivision and land development plans shall be designed
to meet the current standards of the commonwealth and federal law
with respect to handicapped accessibility and verification of compliance
shall be provided to the Borough by the applicant.
A.
Upon installation, manholes shall be vacuum tested and all sanitary
sewer lines shall be lamped and air tested by the developer in the
presence of the Inspector. Air tests shall be conducted in accordance
with the Borough construction standards.
B.
All construction materials used in sewers, streets, sidewalks and
other required improvements shall be tested by a qualified testing
laboratory. The cost for such tests shall be borne by the developer.
C.
Copies of the test reports shall be provided to the Borough Engineer
and to the Borough Secretary.
