[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
This Part 10 is intended to comply with the requirements of the Pennsylvania "Storm Water Management Act," Act No. 167 of October 4, 1978 (P.L. 864),[1] and its regulations. The purposes of this Part are to promote the general health, safety, and welfare of the community, regulate the modification of the natural terrain and alterations of existing drainage from land disturbance, new subdivisions, and new land developments in order to control erosion and sedimentation of soils and preserve stream channels and water quality, as well as provide for design, construction and maintenance of storm drainage facilities for controlling stormwater, erosion, and sedimentation and maintaining the quality of the watersheds within Forward Township.
[1]
Editor's Note: See 32 P.S. § 680.1 et seq.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
The following activities shall be regulated by this Part 10:
A. 
Land development.
B. 
Subdivision.
C. 
Construction of new or additional impervious or semipervious surfaces (driveways, parking lots, etc.).
D. 
Construction of new buildings or additions to existing buildings.
E. 
Diversion or piping of any natural or man-made stream channel.
F. 
Installation of stormwater management provisions or appurtenances thereto.
G. 
Earth disturbance.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
For the purposes of this Part, certain terms and words used herein shall be interpreted as stated in Part 2 of this chapter.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
The costs of review and inspection by the Engineer for the Township of the stormwater management system as proposed by the developer shall be borne by the developer, whether or not the plan is ultimately approved. The Engineer shall review such changes as the developer may make in his plan for compliance with the Engineer's recommendations and shall advise the Board of Supervisors whether the revised plan is in compliance or not. The Board shall direct the Engineer to inspect a stormwater management area during its various stages of construction and to point out to the contractor, the developer and Board any deviations from the design as approved.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
The owner or developer shall enter into a legal agreement which shall indemnify and hold the Township harmless from any and all liability relating to storm drainage collection systems and their discharge during construction of the system and thereafter. The owner or developer shall secure, where necessary, in the opinion of the Engineer for the Township, all off-site easements for storm drainage. In the event the Township, in its sole discretion, determines that the Township shall be responsible for maintenance of a retention area, the developer shall provide permanent access easements to, into, within and around the retention area. In the event that the Township assumes maintenance, either through agreement with the developer or because the developer fails to maintain the area, the developer shall pay to the Township all costs and expenses necessary to maintain the same, but not less than $0.50 for each square foot of area to be maintained, which shall be deposited in an account from which the principal and the interest shall be used only for the maintenance of the stormwater management system and no other municipal purpose. The exact square foot unit price amount shall be determined by the Township when executing the maintenance agreement when the amount is agreed upon prior to actual Township maintenance. If maintenance is performed by the Township as a result of the developer's nonperformance, the Township shall assess the costs of maintenance based upon actual costs incurred by the Township, but in an amount not less than the unit price of $0.50 heretofore written.
2. 
In the event that the developer should default in regard to the aforementioned square foot maintenance agreement for whatever cause and it becomes not feasible for the Township to collect from the developer the minimum $0.50 per square foot for the area to be maintained, the Township may lien each property within and served by the development plan for the individually computed pro rata cost incurred by the Township when providing maintenance according to this provision.
3. 
Where it is the intention of the developer to provide maintenance and repair of a retention area, the developer shall provide the Township with a binding legal document pledging and warranting himself to continued performance, if warranted in the opinion of the Township; the developer shall furnish the Township with an acceptable bond in an amount not less than the aforementioned minimum amount to ensure future financial capability. In addition, there shall be the requirement that the development plan or subdivision plan, when presented to the Township for approval, contains the statement that each individual landowner in the development plan for which a stormwater management control plan is approved, his heirs, successors or assigns share proportionately in the responsibility for maintenance and repair of the facility, should the developer fail to fulfill his obligations as set forth. The statement shall be a provision of the deed that is issued for each and every individual lot, parcel or tract within a development plan or subdivision plan when such development plan is subject to stormwater management control.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
Any delineated wetland areas shall not be drained or flooded permanently unless the proper permits are obtained from the Pennsylvania Department of Environmental Protection and the United States Army Corp of Engineers for such work.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
Storm sewers, culverts, catch basin inlets and related installations shall be provided to ensure the controlled flow of natural watercourses and to guarantee the drainage of all low points along the curb or gutter lines, as well as at intervals related to slope, of all streets in or adjacent to the plan. Where driveways cross gutter lines, they shall be designed to allow passage of stormwater along the gutter line or passage via a pipe below the driveway entrance of sufficient size to carry the runoff. In no case shall stormwater flowing down a driveway be permitted to cross a public street.
2. 
Catch basin inlets shall be double brick at least eight inches in thickness, cemented on both sides, or precast concrete meeting at least the standards of the current edition of PennDOT's specifications sheet RC-52. Catch basins shall be located no further apart than 400 feet along a single continuous slope. Actual spacing within the minimum limits specified shall be planned to efficiently intercept proposed surface flows.
3. 
Storm sewers installed shall have a minimum diameter of 15 inches and a minimum gradient of 1%.
4. 
A stormwater drainage system which is adequate to serve the needs of the proposed subdivision, land development, or mobile home park shall be constructed for same. All construction shall comply with this Part, PennDOT specifications, the Pennsylvania Stormwater Management Act and with the Pennsylvania Department of Environmental Protection (where construction will affect an existing waterway). Stormwater drainage plans shall be approved by the County Engineer or his or her designated representative before construction may commence.
5. 
If an adequately sized, existing stormwater drainage system exists within 500 linear feet of the proposed system, it shall be connected to same. If a developer cannot connect the proposed system with an existing system because one does not exist, an existing system is not adequately sized, or access is unattainable because of ownership, then storm drainage shall be diverted to an existing natural watercourse or as permitted by DEP and shall not drain to other property, except by proper easement in compliance with this Part, and shall not cause hazard to persons or property.
6. 
Drainage ditches or channels may be constructed by the developer, if approved by the County Engineer or designated representative, to control surface drainage. Drainage ditches and channels shall have a minimum gradient of 1% with side slopes no steeper than one vertical to two horizontal and shall be seeded with an acceptable vegetation, suitable to prevent erosion.
7. 
Roof drains shall be extended to a paved gutter and connected to a storm sewer system where possible. Where a connection to a system is not possible, roof drains shall be diverted to an approved drainage ditch or channel. At no time shall a roof or foundation drain be connected to a sanitary sewer system.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
In designing the storm drainage system, the developer shall use as his guide the publication "Urban Hydrology for Small Watersheds" Technical Release No. 55, United States Department of Agriculture, Soil Conservation Service, January 1975, as amended. For developments larger than three acres, the SCS twenty-four-hour Type II rainfall distribution shall be used for analyzing stormwater runoff control facilities (except storm runoff collection and conveyance facilites). For development sites less than three acres, the rational method may be used to determine peak flows and the modified rational method used for design and routing of runoff control facilities.
2. 
The predevelopment condition of the parcel to be developed, as determined by the Engineer for the Township, shall be considered the state of the land surface on the date that the developer entered into an agreement to purchase the property. If the property has been partially or completely developed at the time of purchase, the Board of Supervisors may, at its option, require the new owner, if he proposed to redevelop or further develop the property, to take remedial action for compliance with the requirements of this subsection, regardless of the condition of the surface; the predevelopment design runoff shall not be more than that generated by a predevelopment land surface condition comparable to a ground runoff curve number of 75 (see Tables 2-1 and 2-2 of TR 55). The developer may pass through stormwater originating upstream of his property, but if he elects to control it, bypass devices he installs shall be capable of handling the ten-year twenty-four-hour peak flow, and he may trade off, as compensation for such installations, control measures that would normally be required on his property, provided the total control system results in equal or better protection for downstream properties.
3. 
The developer shall consult with the Butler County Office of the Soil Conservation Service before developing his storm drainage plans. The Township and others reviewing a stormwater control plan will use discretion in considering unusual conditions, such as drainage from several basins on the same property under development.
4. 
A ten-year storm frequency shall be utilized in designing facilities serving local, commercial/industrial and marginal accessways and access roads to multiple business properties. All longitudinal and side drains and slope pipes for street, road and highway systems will also be designed considering the ten-year storm frequency. Culvert cross drains and any other type of drainage facility in an underpass or depressed roadway section shall be designed utilizing the following storm frequencies: arterial highways 25 years and collector, local and other streets 10 years. Greater design standards may be required by the Planning Commission where justified on individual projects.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
The stormwater drainage plan of a subdivision, development plan or mobile home park shall be designed to assure that, after development, stormwater does not leave the property at a greater velocity or volume per second than before development commenced. The ten-year twenty-four-hour peak flow (3.80 inches of precipitation in 24 hours or as may be subsequently revised), creating slightly out-of-bank conditions in downstream drainageways, shall be the maximum release rate condition for water leaving the property. The maximum storm of record over a twenty-four-hour period during the preceding 25 years (4.35 inches of precipitation in 24 hours or as may be subsequently revised) shall be the design condition to be used in developing the storm drainage system. The difference between the twenty-five-year storm and the ten-year storm shall be stored on the property for gradual release at the ten-year rate.
2. 
The Supervisors reserve the right to require the developer to provide storage for the difference between the maximum storm of record over a twenty-four-hour period during the preceding 100 years (5.00 inches of precipitation in 24 hours or as may be subsequently revised) and the twenty-five-year storm.
3. 
When the area to be developed is composed of more than one watershed, and discharges from the watersheds do not occur at a common point, each watershed shall be managed separately so that no uncontrolled runoff may occur from any major portion of the developed total site.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
The stormwater drainage system of pipes and conduits shall be designed to transport the stormwater runoff generated by the twenty-five-year (4.35 inches of precipitation), twenty-four-hour-peak-flow storm.
2. 
When tradeoff is utilized as mentioned in § 22-1008 above and storm drains will bypass the stormwater management control facility, pipes and conduits may be designed to transport stormwater runoff generated by a fifteen-year (4.05 inches of precipitation), twenty-four hour peak flow.
3. 
All runoff transported over land either by effluent from sewers or from nonsewered open lands tributary to the retention facilities shall be conveyed in planned facilities, such as heavily vegetated channels or otherwise stabilized drainageways, to the stormwater retention facilities. Facilities, either constructed or natural, shall be designed to carry the peak flow at nonerosive velocities.
4. 
Design, layout and construction of diversions shall be in accordance with the latest edition of the United States Department of Agriculture Soil Conservation Service Engineering Field Manual, Chapter 9.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
Retention areas, as required to impede runoff, may be varied in type and form. Temporary impoundment of stormwaters may be managed by said storage of water within underground facilities (i.e., as rock fills, buried conduits, etc.), on flat parking or other surface areas, on rooftops, in excavated ponds, in embankment ponds (singly or in multiples thereof), or in any combination of the above. Structural limitations of impoundment facilities shall be thoroughly reviewed by the developer and be approved by the appropriate agencies having jurisdiction.
2. 
Retention areas shall be designed to meet or exceed the following minimum standards and the applicable standards of the following referenced documents:
A. 
"Handbook for Earthmoving Activities and Erosion and Sedimentation Control in Butler County," latest revised edition;
B. 
"Soil Conservation Service–Construction Specifications and Engineering Standards for Embankment Ponds," Technical Guide Section IV, pages 378-1 to 2378-15, dated May 1977, or the latest revised edition.
3. 
Except where a permanent ponding facility is approved by the Township, all retention areas shall be designed to be drained completely.
A. 
Retention Area as a Parking Lot Facility.
(1) 
The low edge of a parking area, curbed or uncurbed, may serve the purpose of an emergency spillway to pass the overflow from a stormwater retention area, provided the embankment below the edge is well stabilized with planting materials and the angle of the slope will not encourage erosion, in the opinion of the Township and other reviewing agencies. The maximum depth of water on a parking area used for stormwater management purposes shall not exceed 12 inches.
B. 
Retention Area as an Embankment Reservoir Facility.
(1) 
Standards.
(a) 
Embankment reservoirs shall be designed to service a drainage area of not more than 20 acres and have a maximum depth at normal design pool of no greater than 10 feet. Embankments in this category shall be known as "Pennsylvania Class III ponds."
(b) 
Prior to design or construction, a soil investigation at the site shall be carried out by the developer. A minimum of two test borings taken at no greater than 50 feet on center across the site of the proposed breastwork may be required. Test borings shall, as a minimum, extend to 10 feet below the level of the case of the impoundment at the breastwork or five feet into bedrock if bedrock is encountered within the minimum ten-foot depth. Test hole results will be furnished as part of project approval documents.
(c) 
The minimum top width of the structure shall be six feet. The minimum elevation at the top of the settled embankment shall be one foot above the water surface in the reservoir with the emergency spillway, and the settled top of the impoundment shall be two feet. Initially, the top of the impoundment shall be constructed 10% higher than the designed height to allow for the occurrence of possible settlement.
(d) 
Fill Material.
1) 
Acceptable fill material for embankment construction shall conform to permitted uses as itemized under Table 3, "Soil Interpretations for Selected Engineering Uses," as published in the Soil Survey for Developing Area in Butler County, Pennsylvania, prepared by the United States Department of Agriculture (USDA), latest revised edition.
2) 
In the event that acceptable embankment material is not available on site, the developer must arrange to provide fill material from an acceptable source off site. Pre-identification of borrow material will be required to be furnished by the developer before permits may be issued by the Township.
(e) 
Foundation Preparation. The foundation area for embankment shall be cleared of all trees, stumps, roots, brush, boulders, sod, topsoil and debris. All channel banks and sharp breaks shall be sloped to no steeper than 1:1. The surface of the foundation area will be thoroughly scarified before placement of the embankment material.
(f) 
Fill Placement.
1) 
Fill shall be placed in maximum six-inch layers at optimum moisture content and shall be compacted to 95% original dry density.
2) 
The material placed in the fill shall be free of all sod, roots, frozen soil, stones over six inches in diameter, and other objectionable material. The placing and spreading of the fill material shall be started at the lowest point of the foundation, and the fill shall be brought up in the six-inch horizontal layers.
3) 
The distribution and gradation of materials throughout the fill shall be such that there will be no lenses, pockets, streaks or layers of material differing substantially in texture or gradation from the surrounding material. Where it is necessary to use materials of varying texture and gradation, the more impervious material shall be placed in the upon stream and center portions of the fill.
(g) 
Embankment impoundments shall be constructed with a foundation cutoff to ensure stability. The cutoff shall extend full length under the embankment fill at or slightly upstream from the embankment center line. If deemed necessary after analysis of test boring results, it shall be extended a sufficient distance beyond the fill to ensure stability and relative watertightness on the downslope terrain at the sides. The cutoff trench shall be constructed of relatively impervious material and shall not be less than three feet in depth and three feet in width at its base. Side slopes shall be no greater than 1:1. In all cases, the cutoff shall extend into a relatively impervious layer of native material.
(h) 
Embankment Slopes. The combined upstream and downstream side slopes of the settled embankment shall not be less than five horizontal to one vertical with neither slope steeper than 2:1. Slopes must be designed to be stable in all cases, even if flatter side slopes are required.
(i) 
Emergency Spillway.
1) 
An emergency spillway is to be provided to convey large flood flows safely past earth embankments.
2) 
The emergency spillway shall be capable of passing the flow created by the maximum storm of record over a twenty-four-hour period during the preceding 100 years. Five inches of precipitation in 24 hours shall be the design condition.
3) 
Constructed earth spillways shall be trapezoidal and will be located in undisturbed or compacted earth. The side slopes shall be stable for the material in which the spillway is to be constructed.
4) 
Earth spillways shall be designed to carry the design peak flow at nonerosive velocities. Nonerosive velocities for the vegetation to be established may be determined from Exhibit 7-3, page 7-14, of the SCS Engineering Field Manual.
(j) 
Pipe Conduits–Drains. Pipe conduits under or through the embankment shall be of minimum Schedule 40 steel pipe, Class III reinforced concrete pipe or 12-gauge full bituminous coated corrugated metal pipe. The pipe barrel shall be placed on a firm foundation to the lines and grades shown on the plans. Selected backfill material shall be placed around the conduit in four-inch layers. Each layer shall be thoroughly compacted with hand-operated equipment to a height of two feet over pipes and other structures before heavy equipment is operated over them. The invert of the pond drain shall be a minimum of three feet below the lowest elevation of water impoundment in the pond. Anti-seep collars shall be installed around the pipe conduit not greater than 28 feet measured along the length of the pipe. Collars shall extend a minimum of two feet in all directions at right angles measured from the face of the pipe. Collars of steel shall be minimum one-fourth-inch steel plate and shall be welded to the pipe conduit for the full pipe perimeter. Reinforced concrete collars shall be minimum 12 inches in thickness. Collars shall be compatible with pipe materials.
(k) 
Pipe Conduit–Inlets. The top of the slotted riser pipe provided for draining the pond shall be not less than 1/3 the maximum impoundment depth measured from the bottom of the impoundment. It shall also be a minimum of four feet above the outfall invert at the inlet to the pond drain. It shall be fitted with a noncorrosive anti-vortex device and trash rack. The inlet pipe, where joined to the pipe drain, shall be firmly anchored to adequate concrete blocking to ensure against flotation.
(l) 
Energy Dissipators. Energy dissipators shall be placed at the outlet of the pond drain pipe and at the outlet of the emergency spillway for a minimum distance of 10 feet from the outfalls. Dissipators shall, as a minimum, be constructed of stone riprap, nominal six-inch diameter. Width shall be sufficient to control the entire flow between the exit channel device.
(m) 
Seeding.
1) 
A protective cover of vegetation shall be established on all exposed surfaces of the embankment spillway and borrow areas to the extent practicable under prevailing soil and climatic conditions. The embankment and spillway shall be fenced where necessary to protect the vegetation.
2) 
Sodding, seeding, liming, fertilizing and mulching shall conform to the standards for permanent seeding in the Pennsylvania Technical Guide available in SCS offices, the current Pennsylvania Agronomy Guide published by Pennsylvania State University, or in the Butler County Handbook for Earthmoving Activities and Erosion and Sedimentation Control.
(n) 
Visual Resource Design. Ponds in areas of high public visibility are to receive careful visual design. The underlying criterion for all visual design is appropriateness. The shape and form of ponds, excavated material and plantings are to relate visually to their surroundings and to their function.
C. 
Retention Area as an Excavated Pond Facility.
(1) 
Side Slopes. Side slopes of excavated ponds shall be such that they will be stable and shall not be steeper than two horizontal on one vertical. Where surface water runoff enters the pond in a natural or excavated channel, the side slope of the pond shall be protected against erosion by hand-placed stone riprap.
(2) 
Emergency Spillway. The crest of the embankment may serve as the emergency spillway if the back slope (the downstream side) is six horizontal to one vertical (6:1) or flatter. Otherwise, a spillway meeting the embankment pond criteria shall be provided.
(3) 
Pipe Conduits–Drains and Inlets. All standards shall be applicable as heretofore written for embankment structures.
(4) 
Placement of Excavated Material. The material excavated from the pond shall be placed in one of the following ways, so that its weight will not endanger the stability of the pond side slopes and where it will not be washed back into the pond by rainfall:
(a) 
Uniformly spread to a height not exceeding three feet with the top graded to a continuous slope away from the pond. Maximum grade shall be two horizontal to one vertical.
(b) 
Uniformly placed or shaped reasonably well with side slopes, assuming a natural angle or repose for the excavated material behind a berm width equal to the depth of the pond but not less than 12 feet.
(c) 
Shaped to a designed form that blends visually with the landscape.
(d) 
Used for low embankment and leveling.
(e) 
Hauled away.
(5) 
Inclusions by Reference. All applicable portions of the written and referenced standards for embankment ponds shall apply as if herein written.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
All graded areas associated with stormwater management and development shall be stabilized with erosion-resisting plantings placed immediately after the completion of grading. Graded slopes produced by placing fill earth over the preexisting surface shall be keyed into the original grade.
2. 
Grades of embankments resulting from preparation of building lots or sites shall not exceed one-foot vertical rise for every two feet of horizontal run for fill slopes or one-foot vertical rise for every 1.5 feet horizontal run for slopes created by excavating in areas that have lain dormant for at least two years, except that steeper slopes may be permitted in areas where, in the opinion of a professional engineer, as evidenced in a written report, conditions are such as to allow slopes up to a maximum grade determined by the engineers, subject to the approval of the Township.
3. 
No grading shall occur within five feet of any subdivision or development plan boundary except as is needed for the entrance of streets or to grade off land immediately adjacent to a street when establishing the finished grade street elevation.
4. 
All persons, partnerships or corporations intending to excavate, fill or grade land in the Township shall be required to apply for a grading permit and shall have a valid grading permit in their possession prior to the start of any grading work. Prior to the issuance of a permit, the site shall be subject to the inspection and approval of the Engineer for the Township. The costs of inspections shall be borne by the applicant at time of permit issuance. Work shall be undertaken in conformance with the requirements of this Part and applicable regulations of Butler County.
[Ord. No. 82-1, 8/15/1982; as amended by Ord. No. 1988-2, 12/13/1988; Ord. No. 2006-1, 6/20/2006]
1. 
The Township Supervisors may elect, at their discretion, to forego stormwater management development plans on a case-by-case basis for residential development only under the following circumstances:
A. 
The developer is an individual lot owner, and the lot to be developed fronts on an existing public road of record.
B. 
The land to be subdivided does not exceed five contiguous lots all of which front on an existing public road of record, and the subdivision meets all other subdivision requirements as set forth in the regulations. Additional contiguous lots in excess of five may be subdivided without formal stormwater management control facilities with special permission when, in the opinion of the Township, runoff generated from the proposed total development will not be in excess of a maximum allowable amount that will ensure continued adequate protection for downstream developed and undeveloped lands and waterways.
C. 
The land area coverage of any individual lot, when fully developed according to the plan submitted, does not exceed the following maximum values: principal structure, 15% of lot area; and driveways, porches, parking lots and appurtenances, 15% of lot area. The remaining undeveloped portion of any individual lot shall have a land surface condition comparable to or less than around runoff curve numbers of 75 (meadowland) according to Tables 2-1 and 2-2 of Technical Release No. 55, United States Department of Agriculture, Soil Conservation Service, January 1975, and as amended.
2. 
Development as specified under §§22 1001 through 22-1006 above is subject to the following restrictions and ongoing controls:
A. 
A subdivider proposing to develop contiguous lots in excess of five must provide analysis of the watershed upstream which passes through his development. Exclusion of stormwater management controls may be considered if the total development does not increase runoff from that watershed beyond that generated according to the following criteria:
B. 
The volume rate of water generated by that watershed shall be computed for the twenty-five-year storm. Ground cover for the computation shall be based upon runoff curve number 75. Volume rate shall also be computed for the post-development runoff curve number based upon the twenty-five-year storm. When computations indicate a greater runoff for post-development conditions than was computed for runoff curve number 75, exclusions of stormwater management development plans will not be considered.