Township of Lower Merion, PA
Montgomery County
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Table of Contents
Table of Contents
A. 
All subdivisions and land developments shall conform to the Official Highway Map, the design standards set forth in this article and all other pertinent sections of this Code.
B. 
Developers shall include the following in the subdivision or land development design:
(1) 
Provision of adequate rights-of-way and improvements.
(2) 
Easements for storm and sanitary sewer facilities in those areas that cannot be immediately joined to the existing storm and sanitary sewer systems of the Township.
(3) 
When required by the Board of Commissioners, reservation of areas and easements for crosswalks, pedestrian access, bikeways and/or bridle trails appropriate to the proposed subdivision or land development.
C. 
Community facilities shall be considered in the approval of subdivision and land development plans. Areas reserved for such facilities should be adequate to serve the additional dwellings or other buildings contemplated by the subdivision or land development.
D. 
Preservation of open spaces, historic sites and structures, natural features of the land and other community assets.
[Amended 5-18-1988 by Ord. No. 3090]
(1) 
Every subdivision or land development plan shall be designed to preserve and protect the natural features of the land, including existing grades and contours, bodies of water and watercourses, large trees standing alone or in groves, street shade trees and specimen trees, scenic and historic points, pedestrian walks and bridle trails that have been in public use and other community assets.
(2) 
The burden shall be on the developer to justify any material changes in the natural features of the land by satisfactory proofs that subdivision or land development would not be feasible without such changes and that there are no practical alternatives. The fact that subdivision or land development would involve greater expense or less density because of the maintenance of certain natural features will not in and of itself be considered a justification of changes in such features.
(3) 
Every subdivision or land development plan shall be designed to preserve and protect historic sites and structures. The burden shall be on the developer to justify any material changes in historic sites and structures by satisfactory proof that subdivision or land development would not be feasible without such changes and that there are no practical alternatives which would permit the preservation of this historical nature of the property. The fact that subdivision or land development would involve greater expense or less density because of the maintenance of historic sites and structures will not in and of itself be considered a justification for material changes or alterations to such historic sites or structures.
(4) 
Preservation of the community. To protect and maintain air and noise level quality, open space, aesthetic quality and the social and economic stability of all parts of the Township and to coordinate subdivision and land development with existing nearby neighborhoods, the Board of Commissioners may impose reasonable buffer requirements when any of the following conditions may reasonably be expected to occur as a result of the proposed subdivision or land development:
(a) 
Substantial changes in the level or quality of air pollutants or the number of people affected by air pollution.
(b) 
Substantial changes in the level of noise or vibration or the number of people affected by noise or vibration.
(c) 
Substantial changes in the site views from nearby premises or in the degradation of the privacy of nearby premises.
E. 
When a subdivision or land development plan is approved subject to conditions requiring the developer to make improvements, the Board of Commissioners shall have the option of requiring the developer to pay the cost of the improvements to the Township at the time of subdivision or land development approval, in which event the Township shall construct the improvements, in lieu of requiring the actual construction of the improvements by the developer. The payment by the developer shall be made only if the developer and the Township agree upon the amount of the payment. If no such agreement can be reached, the developer shall construct the improvements.
[Added 12-17-1980 by Ord. No. 1933]
A. 
Every effort should be made to avoid removal of trees having a caliper of six inches or greater from the property in the process of subdividing, land developing, grading or installing improvements. Where, in the judgment of the Board of Commissioners, such removal is unavoidable, the applicant shall install trees in such locations and of such size, variety and quantity as the Board of Commissioners shall direct.
B. 
Notwithstanding the six-inch-caliper limitation, no substantial area of smaller trees or shrub cover shall be removed without the provision of comparable replacement as approved by the Board of Commissioners. A plan and a statement of material to be removed and/or demolished shall be submitted for approval.
C. 
Wooded lots, as defined in § 155-167.6 of the Zoning Ordinance, must meet the requirements of Article XXVIIIB of Chapter 155.
[Added 9-18-1985 by Ord. No. 2084]
A. 
The construction specifications for all improvements shall be those contained in the Lower Merion standards and specifications for improvement construction.
B. 
Where literal compliance with the standards herein specified is impractical, the Board of Commissioners may modify or adjust the standards to permit reasonable utilization of property while at the same time securing substantial conformance with the objectives of this article.
A. 
Arrangements. Streets shall be arranged in conformity with the Official Highway Map, considered in relation to both existing and planned streets and located so as to allow proper subdivision or land development of surrounding properties. Tertiary arterial and through highways shall be connected with existing streets and highways so as to form continuations thereof. Minor streets shall be laid out so as to discourage their use as secondary streets or through highways.
B. 
Conformity with topography. Streets shall be adjusted to the contour of the land so as to produce usable lots and streets of reasonable grade, alignment and drainage.
C. 
Right-of-way and paving widths.
(1) 
Streets. The minimum widths of the rights-of-way and the paving shall not be less than the following unless approved by the Board of Commissioners upon recommendations by the Planning Commission and Township Engineer. Plans submitted under the requirements of the Open Space Preservation District shall be permitted to modify the requirements for a minor street, provided that the right-of-way is not less than 34 feet and the paving width is not less than 18 feet. In all events, the right-of-way shall extend no less than eight feet beyond both edges of the paving.
[Amended 12-19-1990 by Ord. No. 3222]
Type of Street
Minimum Right-of- Way Width
(feet)
Minimum Paving Width
(feet)
Minor
50
27
Tertiary arterial
60
27 to 38
Secondary arterial
60
38
Primary arterial
80
48
(2) 
Culs-de-sac.
(a) 
The minimum widths of the rights-of-way and the paving shall not be less than the following unless otherwise approved by the Board of Commissioners upon recommendation by the Planning Commission and Township Engineer.
[Amended 12-19-1990 by Ord. No. 3222]
Number of Lots or Dwelling Units According to Plan
Minimum Right-of- Way Width
(feet)
Minimum Paving Width
(feet)
1 to 7 lots in R 2, R 1, R A and R AA Districts
50
20
1 to 7 lots in R 3 to R 7 Districts, inclusive
50
27
1 to 7 lots in commercial and manufacturing zoning districts
50
271
More than 8 for all zoning districts
50
271
Open space preservation developments
34
18
NOTES:
1The Township Engineer may require additional width of paving in commercial and manufacturing districts in accordance with the American Association of State Highway Officials Standards.
(b) 
The two corner lots at the intersection of a cul-de-sac with an existing street are to be considered in determining the width of paving for the cul-de-sac, whether or not they utilize the cul-de-sac for access.
(c) 
In determining the number of dwelling units, both existing and proposed dwelling units are counted.
(3) 
Grading. The shoulders shall be graded to the full width of the right-of-way and provision made for slopes beyond the right-of-way.
D. 
Termination of streets; turning area.
(1) 
Streets. In the case of the temporary termination of a street, a temporary turnaround shall be constructed so that the paving shall have an outer radius of 25 feet and extend to within five feet of the property line.
(2) 
The developer will be required to remove and adjust the turnaround paving when extending the new street construction.
(3) 
Culs-de-sac.
(a) 
A cul-de-sac permanently terminated will not be approved when a through street is practicable. The developer shall have the burden of showing the impracticability of the through street in order to justify a cul-de-sac.
(b) 
A cul-de-sac permanently terminated exceeding 400 feet in length may be approved, provided that such extra width of paving as may be determined necessary by the Board of Commissioners is installed.
(c) 
A cul-de-sac permanently terminated shall have a circular turnaround with a minimum right-of-way radius of 50 feet and an outer paving radius of 40 feet.
E. 
Intersections.
(1) 
Right-of-way. Wherever practicable, right-of-way lines shall intersect at right angles and shall be rounded by a tangential arc having a minimum radius of 10 feet.
(2) 
Curbs. Wherever practicable, curblines shall be rounded by a tangential arc, the minimum radius of which shall be 25 feet. The grade lines of the curb at intersections shall intersect if the tangents are extended.
(3) 
Secondary or primary arterials. Wherever practicable, the number of intersections with through highways shall be kept to a minimum and shall be located at least 1,000 feet apart.
(4) 
Sight distance or limit of daylighting for intersections. Proper sight lines shall be maintained at intersections of streets. There shall be measured along the center line a minimum clear sight triangle of 75 feet from the point of intersection. No building or other obstruction will be permitted in this area. Any obstruction to sight shall be removed at the time the street is graded or at the time a building or structure is erected on the adjacent lot, whichever shall first occur.
F. 
Alignment.
(1) 
Sight distance. A minimum sight distance of 250 feet for tertiary arterial or secondary arterial streets and 100 feet for minor streets, measured at the center line and at the driver's eye height of four feet, shall be provided.
(2) 
Horizontal curves.
(a) 
Horizontal curves shall be used at all changes in alignment in excess of 2°.
(b) 
Long radius curves shall be used rather than a series of curves connected by short tangents.
(c) 
Minimum radius curves at the end of long tangents will not be approved.
(d) 
Minimum radii of the center line on horizontal curves shall be 232 feet on intercommunity service or secondary streets and 100 feet on local residential streets.
(e) 
Reverse curves shall be separated by tangents of 50 feet or more.
(f) 
Superelevation and additional width shall be used for curves of less than 600 feet radii on intercommunity service or secondary streets and of less than 300 feet radii on local residential streets.
(3) 
Vertical curves shall be used at changes in grade of more than 1%. The length of the curve shall approximate 50 feet on intercommunity or secondary streets and 25 feet for local residential streets for each 1% of change in grade. Over summits or in sumps, vertical curves shall not produce excessive flatness in grade.
(4) 
Street jogs with center line offsets of less than 125 feet are prohibited.
G. 
Grade.
(1) 
Limits.
(a) 
The minimum grade shall be 1%.
(b) 
Grades in excess of 5% are to be avoided on all streets wherever practicable.
(c) 
The maximum grade shall be 10% for local residential streets and 7% for intercommunity service or secondary streets.
(2) 
Street intersections. The grade within 50 feet of any side of an intersection or the outer perimeter of a turnaround shall not exceed 3%. The grade will be measured along the curb or flow lines of the street.
(3) 
Curve-grade combinations. A combination of minimum radius horizontal curves and maximum grades will not be approved.
H. 
Street names and signs. The naming of streets shall conform to the requirements of Chapter 133, Article VI hereof. Names for all new streets must be shown on all plans. Street signs shall be placed at each street intersection. They shall be four-way signs of such material, size, height and location as specified by the Township Engineer and in conformity with the existing signs already established in the Township. Street signs for existing and new streets shall be furnished and erected by the Lower Merion Department of Public Works at the developer's expense.
[Amended 11-20-2002 by Ord. No. 3659]
I. 
Obstructions. No fence, hedge, shrubbery, wall, planting or other obstruction shall be located within the right-of-way. Sight at intersections shall not be obscured by such obstructions. Additional areas free of obstructions shall be provided for temporary turnarounds in case of temporary termination of streets exceeding 400 feet in length.
J. 
No subdivision or land development showing reserve strips controlling access to streets shall be approved. The control and disposal of land comprising such strips may be conveyed to the Township under conditions approved by the Board of Commissioners.
K. 
Subdivisions or land developments that adjoin or include existing streets that do not conform to width as shown on the Official Highway Map or the street width requirements of this chapter shall dedicate additional width along either one or both sides of said road. If the subdivision or land development is along one side, only 1/2 of the required extra width shall be dedicated.
L. 
Private residential and commercial driveways.
[Amended 9-16-1981 by Ord. No. 1969; 1-19-1983 by Ord. No. 2015]
(1) 
No more than five dwelling units may share a common driveway. Private driveways shall be so located, designed and constructed as to provide a sight distance designed according to American Association of State Highway Officials Standards at intersections with streets with a stopping space on the drive the length of a car, with a grade not in excess of 5% behind the right-of-way line. Excessive driveway grades that may create a hazard at either street or interior terminus will not be permitted. Where difficult problems of driveway curvature and grades in excess of 10% on residential driveways are likely to be present, the developer shall submit for approval details of driveway location and grade before lot lines and house location and grade are finally determined. Grades of new residential driveways shall not exceed 14%. Grades of new commercial driveways shall not exceed 7%. Crossover easements are required and must be noted on the plan and included in all affected deeds.
(2) 
Private driveways which exceed 200 feet in length frequently present difficulties in and impediments to the delivery of municipal and emergency services and present difficulties in vehicular passage. Therefore, the Board of Commissioners may impose one or more of the following additional construction requirements to alleviate such difficulties and impediments as it determines necessary for proposed private driveways which exceed 200 feet in length:
(a) 
Driveways which exceed 200 feet in length shall be constructed to Township road standards and shall have a minimum width of 10 feet.
(b) 
Pull-outs shall be installed at intervals of no more than 200 feet and shall have dimensions of nine feet by 19 feet.
(c) 
Driveways which exceed 400 feet in length shall be constructed with a turnaround using a Y or a T or a circular configuration with a twenty-five-foot radius at the terminus.
(d) 
Driveways which exceed 600 feet in length shall have private hydrants installed at such intervals as shall be mandated by the Fire Marshal for residential streets.
(e) 
If literal compliance with any of the foregoing requirements would be impractical, the Board of Commissioners may modify or adjust such requirements to permit reasonable utilization of property while at the same time securing substantial conformance with the objectives of this section.
M. 
No street may be created within a tract that would impose on an abutting property an increased setback requirement under the provisions of Chapter 155 of the Township Code.
[Added 10-15-2003 by Ord. No. 3691]
A. 
Sidewalks shall be provided along heavily traveled streets and at any location where the Board of Commissioners shall determine that sidewalks are necessary for public safety or convenience. Sidewalks may be waived, at the discretion of the Board of Commissioners, within open space preservation developments where it can be demonstrated that the objectives of Chapter 155, Article XXVI, Open Space Preservation District, § 155-142, will be furthered. All sidewalks shall be a minimum of five feet wide, except as otherwise provided in Chapter 155, Zoning.
[Amended 12-19-1990 by Ord. No. 3222; 10-18-2017 by Ord. No. 4119]
B. 
Location. Sidewalks shall be located in the shoulder strip of the right-of-way and as far from the curb as is practicable. The grade and paving of the sidewalk shall be continuous across driveways except in certain cases where heavy traffic volume dictates special treatment. The grade and alignment of all sidewalks shall be approved by the Township Engineer.
C. 
Crosswalks. Crosswalks not less than 10 feet wide and with paving not less than four feet wide may be required where necessary to provide access to schools, churches, parks and commercial areas, and the responsibility of maintaining such crosswalks shall be contained in the deeds of the abutting property owners.
D. 
Curbs shall be provided for all streets, except as approved otherwise by the Board of Commissioners, and shall be in accordance with the construction standards. Curbs may be waived at the discretion of the Board of Commissioners if the lots abutting the street have an average net area of 45,000 square feet and an average minimum frontage of 130 feet or where it can be demonstrated for Open Space Preservation District developments that the objectives of § 155-142 will be furthered.
[Amended 12-19-1990 by Ord. No. 3222]
Public rights-of-way for the use of pedestrians and equestrians may be required where the right-of-way continues an existing trail or bridle path, where the right-of-way will connect with an existing right-of-way on an adjoining property or where the right-of-way will extend to another street or alley or to the boundary line of a property capable of further subdivision and there is no convenient alternate access route. Such rights-of-way shall normally be not more than 10 feet in width and, at the option of the developer, may be located adjacent to existing or proposed lot lines or in such manner as to minimize any obstruction to the development. Existing rights-of-way may be relocated reasonably if a connection with a right-of-way on an adjoining property is maintained.
Shade trees shall be installed on both sides of all streets subject to the approval of the Shade Tree Commission at a minimum spacing along each side of the street of 30 feet on center. The variety shall be approved by the Lower Merion Shade Tree Commission. The method of installation and location shall be installed at a minimum size of two-inch caliper at a minimum distance of six feet from the inside edge of the sidewalk or right-of-way line. Trees shall be guaranteed for two years, and dead trees shall be replaced in the next planting season. Wherever provisions of Chapter 128 of this Code impose restrictions more extensive than those of this chapter, the provisions of Chapter 128 of this Code shall govern.
In the instance where the Board of Commissioners determines that buffer planting is necessary to protect the general welfare of the public, planted buffers shall be installed to provide a year-round visual screen of such width, height, size, locations, and planting materials as approved by the Board of Commissioners or the Land Development Committee pursuant to § 135-12 of this chapter. The size, variety and planting design of the buffer area shall be as approved by the Board of Commissioners or the Land Development Committee pursuant to § 135-12 of this chapter.
[Amended 4-18-2000 by Ord. No. 3566]
All subdivisions and land development shall be monumented as directed by the Township Engineer. Permanent survey monuments shall be of stone or concrete and located on the right-of-way lines at corners, at angle points and as otherwise required. Monuments shall be indicated on all plans. They shall be placed after a new street has been completed. The center line of all new streets shall be marked with spikes and referenced to permanent monuments or structures.
The Township has established a system of 150 bench marks giving elevation throughout the area based on the United States Coast and Geodetic Sandy Hook Datum. Information as to location and elevations of these bench marks is available upon request made to the Lower Merion Department of Public Works. All contours and elevations shown on plans must be based on this system.
A. 
Required locations. Alleys shall be provided in commercial districts as specified in Chapter 155, Zoning, to provide access to off-street parking and loading and unloading facilities. Alleys in residence districts will not be approved in the absence of special conditions requiring them.
B. 
Right-of-way width. The width of the right-of-way shall not be less than 20 feet, and the width of the paving shall be not less than 16 feet. Greater widths may be required if necessitated by the proposed use.
C. 
Intersection of right-of-way lines. Intersections of right-of-way lines shall be rounded by a tangential arc, the minimum radius of which shall be 25 feet, and the edge of the paving at intersections shall be rounded by a tangential arc, the minimum radius of which shall be 25 feet.
D. 
Turning area. An adequate turning area shall be provided at any end of an alley which is not an intersection with a street or another alley.
E. 
Obstructions. No fences, hedges, shrubbery, walls, planting or other obstructions shall be located within the right-of-way. Reasonable sight distance shall be provided at intersections with streets.
A. 
Depth, side lines and irregular configuration.
[Amended 5-15-1985 by Ord. No. 2071; 10-15-2003 by Ord. No. 3691]
(1) 
A lot may not be created whose depth is greater than 2.5 times its width.
(2) 
A lot may not be created which is excessively irregular unless reasonably dictated by the topography of the land or other natural feature. An excessively irregular lot is one which is not four sided or which has a boundary line the length of which is more than 2.5 times the width of the opposite or adjacent boundary line.
(3) 
The side lines of a lot shall be at right angles or radial to the right-of-way lines.
(4) 
Any portion of a lot not permitted to be included in the required lot area as provided in § 155-128 of the Township Code shall be disregarded in determining compliance with the standards created by this subsection.
B. 
Narrow lots may be created only when authorized by the Board of Commissioners as a conditional use under the provisions of § 155-128 of the Code of the Township of Lower Merion.
[Amended 5-15-1985 by Ord. No. 2071; 2-18-1987 by Ord. No. 3034]
C. 
No lot shall be approved for a subdivision where the access crosses a floodplain district, unless approved by the Zoning Hearing Board, or where access could be gained only by violating the standards for driveways contained within this chapter or where the lot does not contain sufficient legal buildable area for the intended use.
D. 
All lots must conform to the zoning district requirements applicable to the parcel being subdivided.
E. 
Adjacent lots owned by the same person may be consolidated by recording a deed describing the lots as a single parcel, without subdivision plan approval, where the only change being made to a lot line is the elimination of one or more of them, subject to administrative review by the Building and Planning Department. This exemption from the approval procedures set forth in this chapter shall be subject to the following:
[Added 1 -15-1997 by Ord. No. 3439; amended 1-19-2002 by Ord. No. 3630]
(1) 
A statement must be placed in the deed acknowledging that it is a deed of consolidation intended to merge the lots and that any future independent use of the lots would require subdivision approval.
(2) 
The application to register the deed shall constitute an application to amend the Township's plan of properties to show the consolidation.
(3) 
Prior to registering such deed, the Planning and Community Development Director shall notify the Zoning Officer of the consolidation.
(4) 
Each deed submitted for registration and recording shall have attached thereto a plan prepared, signed and sealed by a registered surveyor showing the metes and bounds, gross and net (after deducting the rights-of-way of any public or private street) areas and error of closure of the consolidated lot. The error of closure shall not be greater than one part in 5,000.
(5) 
Upon merger by deed, use or subdivision approval, adjacent lots shall lose their separate identity for all purposes relating to their development.
A. 
Block length and width of acreage within boundary roads shall be such as to accommodate the size of lot required in the area by Chapter 155 of this Code to provide for convenient access, circulation control and safety of street traffic.
B. 
In blocks over 1,000 feet long, pedestrian crosswalks may be required in locations deemed necessary by the Board of Commissioners.
C. 
For commercial, group housing or industrial use, block size shall be sufficient to meet all area and yard requirements for such use.
House numbers shall be assigned by the Lower Merion Department of Public Works, pursuant to Chapter 64 of this Code.
The following regulations shall apply as they affect parcels upon which buildings exist at the time of the subdivision or land development:
A. 
The subdivision of a tract which creates nonconforming yards for existing buildings contrary to the requirements of Chapter 155 of this Code will not be approved. Nonconforming front yards may be approved if necessary to obtain proper street alignment.
B. 
Alterations and replacements will be permitted within the existing structure, but exterior extensions of the building must conform to the requirements of Chapter 155 of this Code.
C. 
In cases where the principal building use has not been as a dwelling, its conversion to a dwelling shall comply with all of the requirements of Chapters 62 and 155 of this Code.
Lots shall be laid out and graded to provide positive drainage away from buildings. Wherever practicable, water should be drained to the street rather than to cross lots contained within the proposed subdivision or land development. Additional water caused by subdivision or land development may not be drained directly onto an adjoining property without the express written consent of the adjoining property owner. Whenever any person, firm or corporation paves, fills, strips, grades or regrades any land or disturbs, modifies, blocks, diverts or affects the natural land or subsurface flow of stormwater or constructs, erects or installs any drainage dam, ditch, culvert, drainpipe or bridge on any premises in the Township of Lower Merion, plans must be submitted to and approved by the Township Engineer. The requirements of Chapter 121 of this Code must be met.
A. 
All sanitary sewer systems and sewage and industrial waste treatment works shall comply with the rules and regulations established by the Department of Environmental Resources of the Commonwealth of Pennsylvania, as amended and revised.
B. 
Wherever practicable, sanitary sewers shall be installed and connected to the Township sanitary sewer system. If outfall sewers are not available but are planned and have been shown in the ten-year growth area as set forth in the 537 Sewage Facilities Plan of the Township, a system of sewers, together with all necessary laterals extending from the main sewer to the street right-of-way line, shall be installed and capped. The Board of Commissioners may waive the above requirements for lots of one acre or larger or in open space preservation developments if the following criteria can be met:
[Amended 12-19-1990 by Ord. No. 3222; 2-19-1997 by Ord. No. 3442]
(1) 
The requirements of § 135-40H are met.
(2) 
Funding and administrative provisions assuring long-term operation and maintenance are provided.
(3) 
Sewage disposal is accomplished through land treatment technologies capable of recharging groundwater aquifers.
C. 
If sanitary sewers are not to be installed initially, easements shall be provided on the preliminary, final and lot location plans and shall show the dedication of appropriate easements across private property for later construction and maintenance of sewers, except where such requirements are waived under Subsection B above. Any deed given for the transfer of a lot in a case where an easement for a sanitary sewer is provided on a recorded plan must contain a legal description of the easement and a provision that the owner is liable for the cost of the sewer when constructed.
[Amended 12-19-1990 by Ord. No. 3222]
D. 
Sanitary sewer pipe shall be sized for full flow from the tract. Larger pipe size may be required to accommodate future extensions.
E. 
Minimum grades shall be 0.4% except at terminal runs, which shall be 1%.
F. 
Manholes shall be placed at every point where the sanitary sewer line changes direction in line or grade. In no instance shall the spacing exceed 400 feet. Manhole frames, covers, buckets and steps may be obtained from the Township.
G. 
Materials. Lateral connections to each lot shown on the preliminary plan 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 Township sewer on the lot or in the abutting street, except that garages accessory to dwellings may be connected to the dwelling line.
H. 
On-site sewage disposal facilities. Whenever it is impracticable to connect with Township sewers, on-site sewage disposal facilities may be permitted upon application and approval by the Sewage Enforcement Officer of the Township of Lower Merion and the Pennsylvania Department of Environmental Resources. Such facilities shall be so located as to permit easy and economical connection to the sewer system of the Township when sewers are installed, except where this requirement is waived under Subsection B above. The type of private sewage disposal system to be installed shall be determined by the results of percolation tests, soil classification and depth of water table, which shall be determined according to the size of the lot. Proof of the adequacy of such facilities shall be furnished by a registered professional engineer or other qualified person. The reports of such tests shall be required at each disposal area, except for large tracts involving more than one disposal system, in which case the prescribed tests shall be made in the amount of one per acre or as designated by the Sewage Enforcement Officer and the Pennsylvania Department of Environmental Protection.
[Amended 12-19-1990 by Ord. No. 3222]
A. 
Stormwater management. Whenever an increase in volume and/or rate of runoff will occur as the result of subdivision or land development, the developer will be required to provide adequate stormwater management facilities in accordance with Chapter 121 of this Code and provide financial security for the completion of those facilities as set forth in this chapter. The design of all stormwater management facilities shall be in accordance with Chapter 121 of this Code and submitted to the Township Engineer for review and, when required, to the Pennsylvania Department of Environmental Protection or the United States Department of Agriculture, Soil Conservation Service. Where retention basins and/or other facilities are required, the responsibility for the continued maintenance and operation of the retention basins and/or other facilities shall be the obligation of the property owner or the Council, as applicable. Any deed given for the transfer of a lot where stormwater piping and/or a retention facility is provided on a recorded lot shall refer to such structures and facilities and provide that the maintenance and operation shall be the continued responsibility of the property owner or the Council, as applicable. A fence four feet in height with a self-closing gate surrounding the retention basin may be required as directed by the Lower Merion Director of Building and Planning.
[Amended 6-15-1988 by Ord. No. 3098; 1-19-2002 by Ord. No. 3631]
B. 
Special drainage problems.
(1) 
Unnatural drainage. Whenever construction stops or concentrates the natural flow of storm drainage in such a way as to affect adjoining properties, approval of the owners must be obtained in writing. Approval of plans by the Township does not authorize drainage affecting adjoining properties.
(2) 
Water originating from other than natural sources, such as swimming pools, air-conditioning units, sump pumps or other dry-weather flow, wherever practicable, shall be discharged into natural watercourses on the property or connected to the storm drainage system of the Township. These facilities may not be used for toxic drainage.
C. 
Runoff computations. Computation of the rate of flow at any given location shall be based on the rational formula:
Q = CIA
Where:
Q
=
Volume in cubic feet per second.
C
=
Runoff factor.
I
=
Intensity of rainfall in inches per hour.
A
=
Watershed area in acres.
In setting the value of the runoff coefficient "C," consideration will be given to the physical features of the drainage basin and the best available data on the future density of development of the drainage basin. In no case shall it be less than 0.40 in a developed area.
D. 
The intensity of the storm shall be based on the following:
(1) 
As a minimum, a ten-year storm shall be used at low points with a relief swale, or a twenty-five-year storm where carried in a pipe.
(2) 
As a minimum, all inlet and culvert designs shall be based on a twenty-five-year storm.
(3) 
As a minimum, a one-hundred-year storm will be used in connection with Chapter 121 of this Code. The Rainfall-Intensity-Duration-Frequency Curve for Philadelphia presented in Technical Paper No. 25, prepared by the United States Department of Commerce Weather Bureau, a copy of which is available for public inspection at the office of the Township Engineer, shall be used.
E. 
Standard headwalls shall be installed on all pipes and, additionally, trash bars shall be installed on all pipes equal to or greater than 24 inches diameter.
F. 
Pipeline design. Storm sewer pipelines shall be designed by either of the two methods described in Subsection F(1) and (2) below. Both shall be based on the Manning equation and shall utilize the friction factors:
n
=
0.015 concrete pipe.
n
=
0.021 corrugated metal pipe.
The minimum allowable pipe size is 15 inches.
(1) 
Pipeline submerged.
(a) 
This method is based on the assumption that, when the storm sewer system is under maximum load, the hydraulic gradient will be at or above the crown of the pipe and that flow in the lines will be controlled by head differentials between structures or other locations where the system is open to the ground surface, such as inlets or outlets, manholes and stream inlets and outlets. The head of water above the crown of any pipe can range from zero feet to a point which will not cause surface flooding.
(b) 
The slope of the hydraulic gradient in any section of storm sewer between opening to the surface shall be calculated on the assumption that the pipe is flowing full at a constant velocity and at the required capacity.
(c) 
The elevation of the hydraulic gradient at any point in the pipe shall be no lower than the crown of the pipe and no higher than the surface of the ground.
(d) 
The elevation of the hydraulic gradient at any point where the system opens to the surface, such as an inlet or manhole, shall be three feet below the surface of the ground.
(e) 
At all structures such as manholes, inlets, etc., where the pipe size does not change, the elevation of the hydraulic gradient shall be dropped 0.2 feet to allow for losses therein. Where the inlet and outlet pipe sizes are not the same, the elevation of the hydraulic gradient shall be dropped an amount based on the following formula:
H
=
0.2 inches + 0.8 (D2-D1)
Where:
D1
=
The diameter of inlet pipe.
D2
=
The diameter of outlet pipe.
If D1 is larger than D2, head loss = 0.2 feet
(f) 
The minimum slope of any pipe shall be such that a minimum velocity of 2.5 feet per second shall be maintained when the pipe is flowing 1/4 full.
(2) 
Pipeline flowing full.
(a) 
This method is based on the assumption that the hydraulic gradient will match the inside top of the pipe when the system is under maximum hydraulic load.
(b) 
For this method, head losses through manholes, inlets, etc., shall be ignored.
(c) 
The minimum slope of any pipe shall be such that a minimum velocity of 2.5 feet per second shall be maintained when the pipe is flowing 1/4 full. When the pipe sizes change, the inside tops of the pipes shall be matched.
G. 
Continuous profiles for each reach of pipe shall be plotted along with the location of the hydraulic gradient and the hydraulic information pertinent to each reach within the system. This information shall include the pipe size and type, the "n" factor, the slope of the hydraulic gradient, slope of the pipe, the design capacity and the velocity at the design capacity.
H. 
Inlets.
(1) 
Single No. 1 open-mouth inlets shall be used on streets with grades of 4% or less. Double No. 1 open mouth inlets shall be used on streets of more than 4%.
(2) 
Sufficient inlets shall be located and constructed so as to collect all of the stormwater flow in the drainage area tributary to the inlet.
(3) 
The gutter of all inlets shall be set not less than two inches nor more than four inches below the gutter grade. The surface of the paving adjacent to the inlets shall be constructed to blend into the lowered gutter grade at the inlet in such a manner that sudden dropoff or dip at the inlet will not be created.
(4) 
Where surface water is collected from two directions at one street corner, inlets shall be placed at, or near, the tangent points of both ends of the radius. The use of an inlet in the radius shall not be allowed.
I. 
Manholes shall be located at intervals of approximately 400 feet where pipe sizes of 24 inches or less are-used and 600 feet apart for larger sizes. Inlets should be substituted for manholes where they will serve a useful purpose. Manhole and inlet castings may be obtained from the Lower Merion Department of Public Works.
J. 
Open channel design.
(1) 
Open channel design should be based on the following hydraulic considerations:
(a) 
Mannings equation.
n = .015 for best concrete lined ditch.
n = .025 for best unlined ditch.
n = .03 to .15 for fair to poor natural streams and watercourses.
(b) 
Velocity.
Excavation Material
Velocity
(feet per second)
Fine sand and firm loam
2.50 to 3.5
Stiff clay and hardpan
3.75 to 6.0
Concrete lined ditch
15
(2) 
Ample freeboard should be provided on all channels.
(3) 
The channel should be designed to conform, wherever possible, to the adjacent ground conditions. This means that it should not be projecting excessively above the surrounding ground or placed excessively below the surrounding ground.
(4) 
Continuous profiles for each reach of open channel shall be plotted along with the adjacent average ground and the hydraulic information pertinent to each reach within the system. This information shall include the type of channel lining, in the "n" factor, the width of the channel bottom, the side slopes, the water depth, the design capacity and the velocity at the design capacity.
(5) 
Open channels shall have a maximum side slope of 3 to 1 and shall have adequate slope protection as required by Chapter 121 of this Code.
K. 
Bridges and culverts. Single-opening culverts are desirable. The design of culverts shall be such as to minimize the probability of debris accumulation. Bridges and culverts shall be designed to meet current Pennsylvania Department of Transportation standards to support expected loads and to carry expected flows. They shall be constructed for the full right-of-way.
L. 
The Pennsylvania Department of Environmental Protection Bureau of Water Quality Management, Division of Dams and Encroachments, requires a permit for construction or changes in a watercourse which drains an area of more than 1/2 square mile. No open watercourses shall be permitted within the right-of-way of any street.
M. 
Location. Wherever practicable, storm drains shall be located behind the curb and within the right-of-way of the street. They shall be protected by a cover of at least 18 inches. The plan shall note that the continued maintenance of storm drains outside the street right-of-way shall be the continued responsibility of the property owner.
N. 
Change in direction. Special storm drain sections of minimum radii of 10 to 15 feet shall be used where abrupt changes are made in alignment.
O. 
Stormwater roof drains. Stormwater roof drains and pipes immediately adjacent to a sidewalk shall not discharge water over a sidewalk but shall extend under the sidewalk to the gutter. Where accessible, the roof drain shall be connected with the storm drainage system of the Township.
P. 
Underground wiring. All electric telephone, television and other communication service facilities, both main and service lines, shall be provided by means of underground cables, installed in accordance with the prevailing standards and practices of the utility and other companies providing such services.[1]
[1]
Editor's Note: Former Subsection Q, concerning water service, which immediately followed this subsection, was repealed 2-18-1981 by Ord. No. 1941.
[Added 2-18-1981 by Ord. No. 1941]
A. 
An adequate public water supply shall be provided by the developer for the proposed use and for fire control.
B. 
Fire hydrants shall be provided by the developer and installed subject to approval of locations by the Township. Furthermore, in the event that a fire hydrant or hydrants are installed to service public or private streets in a subdivision or land development, the developer shall deposit funds or securities in escrow sufficient to cover the cost of the annual fire hydrant rental charge imposed by the water utility provider for a prospective period of 10 years of hydrant rental.
[Added 5-11-2005 by Ord. No. 3742; amended 9-21-2005 by Ord. No. 3753; 5-10-2006 by Ord. No. 3777]
All new electric, telephone and communication service facilities, both main and service lines, shall be provided by underground cables, installed in accordance with the prevailing standards and practices of the utility or other companies providing such services, except where it is demonstrated to the satisfaction of the Board of Commissioners that the underground installation herein required is not feasible because of the physical condition of the lands involved. All proposed underground cables which are within the right-of-way of a street shall be located as specified by the Board of Commissioners.
[Added 5-11-2005 by Ord. No. 3742; amended 9-21-2005 by Ord. No. 3753; 5-10-2006 by Ord. No. 3777]
Where an applicant seeks approval for the development of a portion of a tract with the intent that the remainder would be developed at a future date, the applicant shall submit with the initial application a concept development plan showing with specificity the portion of the tract intended for current development, and showing in concept form the manner in which the balance of the tract might be fully developed in conformance with Township regulations. The intent of such a submittal is to enable the Township to review the basic site design concept, to advise the applicant as to potential problems and concerns that full development of the site would entail, and to assure that the current development of the property properly anticipates the future development with respect to land use, traffic movement, parking, building placement, required infrastructure, and impact on abutting properties, when proper planning techniques are applied. The concept development plan must present a comprehensive overview of potential uses to which the property can be put in conformance with current Township codes. The failure to present such a plan, unless waived by the Board of Commissioners, shall constitute a separate and distinct basis for denying a subdivision and/or land development plan application.
[Added 6-19-2008 by Ord. No. 3855]
Development which is required to meet greening standards shall comply with the following regulations:
A. 
Land development plans must contain elevations and conceptual sketches demonstrating compliance with the greening standards set forth herein.
B. 
Each addition and new construction project shall comply with the greening standards in Table 1 and provide the greening elements set forth in Table 2.[1]
(1) 
The greening elements in Table 2 may be clustered or evenly spread along a property's frontage, provided that a minimum of 50% of the requirement is met within each 100 linear feet of frontage.
[1]
Editor's Note: Table 1 and Table 2 are included at the end of this chapter.
C. 
The total number of points required in Table 1 for an application are determined by dividing the total frontage of the subject property by 25. This total is then multiplied by the amount column in Table 2.[2]
[2]
Editor's Note: Table 1 and Table 2 are included at the end of this chapter.
D. 
The following standards apply to the urban garden item in Table 2:[3]
(1) 
A minimum of 60% of the garden area shall be landscaped with trees, vines, shrubs and seasonal flowers.
(2) 
One fixed seating space is required for each 50 square feet of garden area. No additional points will be awarded for this item.
(3) 
A trash container shall be provided in the garden area.
[3]
Editor's Note: Table 2 is included at the end of this chapter.
E. 
The following standards apply to the plaza, square and courtyard item in Table 2:[4]
(1) 
The area shall be visible and accessible from a public walkway or sidewalk.
(2) 
Thirty percent of the area shall be landscaped with trees, shrubs and mixed plantings with year-round interest. One tree is required for every 500 square feet.
(3) 
Paving materials that may be used are limited to the following: unit pavers, paving stones or concrete. No more than 20% of the area may be concrete.
(4) 
One seating space is required for each 50 square feet of plaza area.
(5) 
No parking, loading or vehicular access is allowed other than for emergency vehicles.
(6) 
Trash containers shall be provided throughout the area.
(7) 
Shade shall be provided by trees, canopies, trellises, building walls or tables with umbrellas.
(8) 
Whenever possible, the area shall be connected to outdoor cafes, restaurants or building entrances and located with maximum direct sunlight to a south or west direction.
(9) 
The applicant must submit a maintenance plan describing how improvements will be managed and maintained. The responsibility for maintenance shall rest with the owner of the property or the condominium association.
(10) 
Where existing conditions of the lot are such that meeting the requirements of this section would be prohibitive, the applicant shall demonstrate that such conditions prohibit compliance. An alternative plan shall be submitted subject to approval by the Board of Commissioners.
[4]
Editor's Note: Table 2 is included at the end of this chapter.