The developer shall erect at every street intersection a street sign or street signs having thereon the names of the intersecting streets and traffic control signs as specified by the Borough Engineer. At intersections where streets cross, there shall be at least two such street signs, and at the intersections where one street ends or joins another street (T-intersections), there shall be at least one such street sign. Street signs shall be of the size, design, materials and colors required by the Borough and shall be installed prior to the issuance of an occupancy permit for the properties which are part of the subdivision or land development.
[Amended 5-8-2018 by Ord. No. 387; 6-14-2022 by Ord. No. 421]
A. General.
(1) The applicant shall construct or install such drainage structures, on site and off site, as necessary to:
(a) Prevent erosion damage and to satisfactorily carry off or detain and control the rate of release of surface waters.
(b) Encourage all runoff-control measures to percolate the stormwater into the ground to aid in the recharge of groundwater.
(c) Carry surface water to the nearest adequate street, storm drain, stormwater BMP, natural watercourse, or drainage facility.
(d) Take surface water from the bottom of vertical grades, to lead water away from springs, and to avoid excessive use of cross gutters at street intersections and elsewhere.
(e) Handle the anticipated peak discharge from the property being subdivided or developed and the existing runoff being contributed from all land at a higher elevation in the same watershed.
(f) Maintain the adequacy of the natural stream channels. Accelerated bank erosion shall be prevented by controlling the rate and velocity of runoff discharge to these watercourses so as to avoid increasing the occurrence of streambank overflow.
(g) Preserve the adequacy of existing culverts. Bridges and similar structures shall be preserved by suppressing the new flood peaks created by new alteration or development of land.
(2) Drainage area boundary plans shall be submitted, reviewed, and approved for all structures, stormwater BMPs, and collection devices.
(3) Additional studies and higher levels of control than the minimum provided in these and other New Britain Borough requirements and criteria may be required by the Borough Council to ensure adequate protection to life and property.
(4) If special geological hazards or soil conditions, such as carbonate derived soils, are identified on the site, the applicant's engineer shall consider the effect of proposed stormwater management measures on these conditions. In such cases, the Borough may require an in-depth report by a qualified soils engineer.
B. Retention of existing watercourses and natural drainage features.
(1) Whenever a watercourse, stream or intermittent stream is located within a development site, it shall remain open in its natural state and location and shall not be piped.
(2) The existing points of natural discharge onto adjacent property shall not be altered without the written approval by the affected landowners.
(3) No stormwater runoff or natural drainage shall be so diverted as to overload existing drainage systems or create flooding or the need for additional drainage structures on private properties or public lands.
C. All subdivisions and land developments are subject, in addition, to the requirements of Chapter
375, Stormwater Management, of the Code of the Borough of New Britain, which is included in these regulations by reference.
D. Stormwater runoff which may result from alteration or development of land shall be controlled by permanent stormwater runoff BMPs that will provide the required standards within this section, Chapter
375, and any other requirements of New Britain Borough. The methods of stormwater control or best management practices (BMPs) which may be used to meet the required standards are described in this section and the Pennsylvania Department of Environmental Protection's Pennsylvania Stormwater Best Management Practices Manual, dated December 2006, as amended (PA BMP Manual). The choice of BMPs is not limited to those referenced in this section and/or the manual. Any selected BMP must meet or exceed the required standards and shall incorporate sound engineering principles and practices.
E. Design criteria for infiltration BMPs. In addition to the design criteria and specifications in the PA BMP manual and any other design criteria in this section, all infiltration BMPs shall meet the minimum requirements:
(1) A detailed infiltration testing and soils evaluation of the project site shall be performed to determine the suitability of infiltration BMPs. The evaluation shall be performed by a qualified professional and, at a minimum, address soil permeability, depth to limiting zones, karst/susceptibility to sinkhole formation, and subgrade stability. Infiltration BMPs shall be selected based on the suitability of soils and site conditions and shall be constructed on soils that have the characteristics defined in §
375-303C(5) and
(6).
(2) All infiltration BMPs shall be provided with an overflow or spillway which safely permits the passing of runoff greater than that occurring during the largest design storm. The overflow or spillway shall be set above the maximum proposed ponding depth.
(3) The infiltration BMP shall be positive overflow controls to prevent storage within one foot of the finished surface above the facility.
(4) Infiltration BMPs shall have a bottom slope of no greater than 1% but shall preferably have a level bottom.
F. Design criteria for bioretention facilities. Bioretention facilities BMPs, including rain gardens, shall be designed in accordance with the design criteria and specifications in the PA BMP Manual and shall meet the following the minimum requirements:
(1) All concentrated discharges directed to a bioretention facility shall be conveyed through a pretreatment filter strip. The filter strip shall be designed to reduce the incoming velocities and to filter out coarser sediment particles. Examples of pretreatment filter strips include sand or gravel diaphragms, grass swales, sand filters, stone check dams, etc.
(2) A minimum planting soil bed depth of two feet for herbaceous plants and three feet for trees and shrubs shall be provided. Planting soil shall be a loam soil capable of supporting healthy vegetative cover.
(3) All bioretention facilities shall incorporate an organic mulch layer. The organic mulch layer shall be standard landscape style, single or double, shredded hardwood mulch or chips. The mulch layer shall be well-aged, uniform in color, and free of other materials such as weed seed, soil roots, etc. The mulch layer shall be applied to maximum depth of three inches. Grass clippings shall not be used as mulch material.
(4) All bioretention facilities shall incorporate native landscaping. Plant species shall be selected based on the ability to tolerate stresses such as pollutants, variable soil moisture, and ponding fluctuations. A mixture of trees, shrubs, and/or herbaceous plant species shall be selected to ensure diversity.
(5) The maximum side slopes of bioretention BMPs shall be four horizontal to one vertical.
(6) A minimum grade of 2% shall be maintained for areas of sheet flow. For channel flow, a minimum grade of 1% shall be maintained. For bioretention facilities relying on infiltration for drainage, rather than sheet or channel flow, a level bottom is permitted.
(7) Bioretention facilities with an aboveground ponding depth of greater than 2.5 feet during any post-development design storm shall be designed in accordance with the requirements of §
385-34G.
G. Design criteria for aboveground basins. Aboveground basin BMPs shall be designed in accordance with the design criteria and specifications in the PA BMP manual and shall meet the following the minimum requirements:
(1) Unless permitted as a special exception by the Zoning Hearing Board, basins shall not be located within floodplains nor within areas of floodplain soils, with the exception that areas of alluvial soils may be utilized if proof is provided by the applicant and accepted by the Borough Council that the area is not subject to flooding.
(2) Basins shall be designed to facilitate regular maintenance, mowing, and periodic desilting and reseeding.
(3) Whenever possible, the side slopes and basin shape shall conform to the natural topography. When such design is impractical, the construction of the basin shall utilize slopes as flat as possible to blend the structure into the terrain. The maximum slope of the earthen basin embankments shall be four horizontal to one vertical.
(4) In order to ensure proper drainage to the basin bottom, a minimum grade of 2% shall be maintained for areas of sheet flow. For channel flow, a minimum grade of 1% shall be maintained. For basins relying on infiltration for drainage, rather than sheet or channel flow, a level bottom is permitted.
(5) The top or toe of any slope shall be located a minimum of five feet from any property line.
(6) The minimum top width of the detention basin berm shall be 10 feet.
(7) If permanent ponds are used, the applicant shall demonstrate that such ponds are designed to protect the public health and safety.
(8) A cutoff trench shall be provided along the center line of any dam or earth fill embankments. The trench shall have a bottom width of not less than four feet, but adequate to allow use of equipment necessary to obtain proper compaction. Side slopes of cutoff trench shall be no steeper than 1:1 ratio. The trench shall be filled with successive thin layers of relatively impervious material, each layer being thoroughly compacted.
(9) All basin embankments shall be placed in lifts not to exceed eight inches in thickness and each lift shall be compacted to a minimum of 95% of modified proctor density as established by ASTM D-1557. Prior to proceeding to the next lift, the compaction shall be checked by a soils engineer employed by the applicant. Compaction tests shall be run on the leading and trailing edge of the berm along with the top of the berm. Verification of required compaction shall be submitted to the Borough prior to utilization of any basin for stormwater management.
(10) All aboveground basins shall be provided with a primary spillway/outlet pipe meeting the following the minimum requirements:
(a) The sizing of the outlet pipe shall be based on the post-construction 100-year storm without utilizing the emergency spillway.
(b) All outlet pipes through the basin berm shall be reinforced concrete pipe with watertight joints.
(c) The pipe barrel and riser shall be placed on a firm foundation. The fill material around the primary spillway shall be placed in four-inch lifts and compacted to at least the same density as the adjacent embankment.
(d) Anti-seep collars shall be installed around the pipe barrel within the normal saturation zone of the basin berms and shall be poured in place.
[1] The anti-seep collars and their connections to the pipe barrel shall be watertight.
[2] The anti-seep collars shall extend a minimum of two feet beyond the outside of the principal pipe barrel.
[3] The maximum spacing between the collars shall be 14 times the minimum projection of the collar measured perpendicular to the pipe.
[4] A minimum of two anti-seep collars shall be installed on each outlet pipe.
(e) All outlet pipes shall have endwalls and energy-dissipating devices (riprap, end sills, etc.) designed in accordance with the Pennsylvania Department of Environmental Protection's Erosion and Sediment Pollution Control Program Manual No. 363-2134-008, as amended and updated (PA E&S Manual).
(11) All aboveground basins shall be provided with an emergency spillway meeting the following the minimum requirements:
(a) Whenever possible, the emergency spillway shall be constructed on undisturbed ground.
(b) Emergency spillways constructed on undisturbed ground may be constructed of reinforced vegetated earth. All other spillways shall be constructed of riprap, concrete checkerblocks, or similar materials approved by the Borough Engineer.
(c) All emergency spillways shall be constructed so that the basin berm is protected against erosion.
(d) The emergency spillway shall not discharge over earthen fill and/or easily eroded material.
(e) The construction material of the emergency spillways shall extend along the upstream and downstream berm embankment slopes. The upstream edge of the emergency spillway shall be a minimum of three feet below the spillway crest elevation. The downstream slope of the spillway shall, at a minimum, extend to the toe of the berm embankment.
(f) The minimum capacity of all emergency spillways shall be the peak flow rate from the post-development 100-year design storm.
(g) The minimum freeboard through the emergency spillway shall be one foot. Freeboard is defined as the difference between the design flow elevation through the spillway and the elevation of the top of the settled basin berm. Six inches, minimum, is required between the 100-year water surface elevation and the emergency spillway crest.
(12) Sediment basins and sediment traps for sediment control during construction shall be designed in accordance with the PA E&S Manual.
H. All other stormwater management BMPs shall be designed in accordance with the design criteria and specifications in the PA BMP Manual and shall incorporate sound engineering principles and practices.
I. Design criteria for drainage channels and swales.
(1) All drainage channels and swales shall be designed to carry the peak flow from a twenty-five-year storm with a minimum of six inches of freeboard. Provisions shall be made to ensure that larger runoff events do not impair public safety or cause damage to adjacent lands or public property.
(2) All drainage channels and swales shall be designed to prevent erosion of the bed and banks and suitable stabilization shall be provided to prevent erosion. The maximum permissible flow velocity shall not exceed those outlined in Table 6.4 Maximum Permissible Velocities (ft/sec) of Channels Lined with Vegetation and its additional notes of the PA E&S Manual.
(3) Vegetated drainage channels shall have a maximum grade of three horizontal to one vertical on those areas to be mowed.
(4) Swales shall be designed to prevent the passage of water onto the cartway during a twenty-five-year frequency storm of five-minute duration.
J. Design criteria for storm drain pipes, inlets, and manholes.
(1) Storm sewers, culverts, and related installations shall be provided:
(a) To permit the unimpeded flow of natural watercourses in such a manner as to protect the natural character of said watercourses and to provide regulated discharge.
(b) To ensure adequate drainage of all low points.
(c) To intercept stormwater runoff along streets at intervals reasonably related to the extent and grade of the area of drainage and to prevent substantial flow of water across intersections.
(2) The design discharge for use in determining gutter flow, spacing of inlets, and for pipe sizing of storm sewer shall be computed by the rational formula Q = CIA, in which Q equal discharge, cubic feet per second; C equal runoff coefficient; I equal rainfall intensity, inches per hour; A equal area, acres.
(a) The storm drainage system shall be designed to carry runoff from the twenty-five-year storm based on rainfall intensities from the latest version of the NOAA Atlas 14 rain data corresponding to the Doylestown rain gage. This data may also be directly retrieved from the NOAA Atlas 14 website: hdsc.nws.noaa.gov/hdsc/pfds/orb/pa_pfds.html.
(b) In all cases where storm drainage is picked up by means of a headwall or inlet structure and hydraulic inlet or outlet conditions control, the pipe shall be designed as a culvert for a fifty-year storm.
(c) The elevation of the hydraulic gradient at any point in the storm sewer system shall be below of the surface of the ground based on the 100-year storm rainfall intensities from the latest version of the NOAA Atlas 14 rain data corresponding to the Doylestown rain gage.
(d) The runoff factors set forth in Table B-7 in Appendix B of the New Britain Borough Stormwater Management Ordinance shall be utilized.
(e) A minimum five-minute storm duration shall be used. Where supported by the drainage area and related plans and calculations, longer storm durations shall be utilized, using the time-of-concentration approach to adjust the time of concentration.
(f) Design shall be based on gravity (non-pressure) flow.
(3) Storm sewer pipes.
(a) All storm sewer pipes shall be reinforced concrete pipe, smooth lined high-density polyethylene, or other pipe material as may be approved by the Borough Engineer.
(b) The Manning's roughness coefficients ('n') set forth in Table B-8 in Appendix B of the New Britain Borough Stormwater Management Ordinance shall be utilized.
(c) The minimum diameter of all storm drainage pipe shall be 15 inches or an equivalent thereto. Where pipe cover is restricted, equivalent pipe arches may be used in lieu of circular pipe.
(d) The minimum slope of any pipe shall be 0.5%.
(e) The top of storm drainage pipes beneath cartways shall be at least six inches below subgrade elevation. Outside of paved areas, all pipes shall have a minimum cover of two feet.
(f) Storm sewers shall be placed within a street right-of-way, parallel to the cartway. When located outside of a right-of-way, storm sewers shall be placed and centered within an easement having a width of not less than 20 feet.
(4) Inlets and manholes.
(a) Abrupt changes in direction or slope of storm drainage pipe shall be avoided. Where there is a such a deflection in the storm pipe system, an inlet or manhole shall be placed at the point of change.
(b) An inlet or manhole shall be provided at all changes of grade, at all locations where a transition in storm sewer pipe size is required, and at all points of convergence of two or more influent storm sewer pipes.
(c) The spacing on inlets and manholes shall not exceed a maximum distance of 450 feet along any one continuous line.
(d) Inlets, manholes, and related tops, covers, and frames shall conform to Pennsylvania Department of Transportation specifications.
(e) All inlets must be designed to accommodate the twenty-five-year peak flow rate. The capacity of all C-, M-, or S-type inlets shall be determined from the Pennsylvania Department of Transportation Design Manual, Part 2, and any amendments.
(f) Spread of runoff in gutters shall not exceed eight feet in width or 1/2 of the travel lane, whichever is lesser, during a ten-year storm event.
(g) At street intersections, inlets shall be placed in the tangent portion rather than the curved portion of the curbing.
(5) Shoulders in cut areas (without swales).
(a) Water flowing in the shoulder shall not encroach more than 2/3 the shoulder width during a twenty-five-year frequency storm of five-minute duration.
(b) The maximum velocity, as determined by Manning's Equation, shall not exceed the allowable velocities in outlined in Table 6.4 Maximum Permissible Velocities (ft/sec) of Channels Lined with Vegetation and its additional notes of the PA E&S Manual for the specific type of shoulder material.
(c) Inlets shall be provided to control the shoulder encroachment and water velocity.
(6) Curbed sections.
(a) The maximum encroachment of water on the cartway shall not exceed two inches in depth at the curb during a twenty-five-year frequency storm of five-minute duration.
(b) Inlets shall be provided to control the encroachment of water on the cartway.
[Amended 9-13-2016 by Ord. No. 377]
A. These regulations are promulgated in an effort to insure that each dwelling unit or commercial, industrial, educational, institutional or office building, hereafter constructed within the Borough, will have an adequate supply of potable water. A hydrogeological study for all potential public water systems shall be submitted with all applications for subdivision or land development.
B. Connection to the public water system shall be required for the following uses:
(1) Five or more single-family detached dwellings.
(2) All multifamily developments.
(3) Mobile or manufactured home parks.
(7) Educational/institutional uses, including hospitals, schools, and nursing home or personal care facilities.
C. The developer shall construct water mains in such a manner as to make adequate water service available to each lot or dwelling unit within the subdivision or land development and shall extend the water mains to the perimeter of the property at a public street and shall terminate the water main in an accessible gate valve. The water supply must comply with the regulations and standards of the Pennsylvania Department of Environmental Protection, with the construction standards of the authority managing or maintaining the public water system, and with the regulations of the Borough.
D. The public water system shall be designed with adequate capacity, storage facility, and appropriately spaced fire hydrants, for firefighting purposes. All public water systems shall be approved by the Borough Engineer, applicable water authority, and the Borough Fire Marshal.
E. All public water systems shall be offered for dedication to the applicable water authority. The water authority shall be under no obligation to accept dedication.
F. Applicants for subdivision and land development shall present evidence to Borough Council that the subdivision or land development is to be supplied by a certified public utility, or a municipal corporation, authority or utility. A copy of a certificate of public convenience from the Pennsylvania Public Utility Commission, or an application for such certification, or a commitment or agreement to serve the property in question, whichever is appropriate, shall be acceptable evidence.