[HISTORY: Adopted by the Board of Supervisors of the Township of Washington as indicated in article histories. Amendments noted where applicable.]
GENERAL REFERENCES
Uniform construction codes — See Ch. 145.
Subdivision and land development — See Ch. 310.
ATTACHMENTS
Attachment 1 - Table 1 - Permissible Velocities for Swales, Open Channels and Ditches Within Uniform Stands of Various Grass Covers, Well MaintainedAttachment 2 - Table 2 - Runoff Coefficients (C) by Type of Surface for Use in the Rational FormulaAttachment 3 - Table 3 - Runoff Coefficients (C) by Land Use For Use in The Rational FormulaAttachment 4 - Table 4 - Inlet Capacity Reduction Factors Assuming Partial CloggingAttachment 5 - Table 5 - n Values for Manning FormulaAttachment 6 - Table 6 - Spacing of Inspection and Cleanout Structures for Storm SewersAttachment 7 - Part A - Stormwater Management PublicationsAttachment 8 - Appendix 1 - Antietam Creek Watershed EastAttachment 9 - Appendix 2 - Antietam Creek East Branch WatershedAttachment 10 - Drawing 1 - Map
[Adopted 4-20-1987 by Ord. No. 101]
The Board of Supervisors of Washington Township finds that:
A. 
Inadequate management of accelerated runoff of stormwater resulting from development throughout the Township increases flood flows and velocities, overtaxes the carrying capacity of streams and storm sewers, greatly increases the cost of public facilities to carry and control stormwater, undermines floodplain management and flood control efforts in downstream communities, reduces groundwater recharge, and threatens public health and safety.
B. 
A comprehensive program of stormwater management, including reasonable regulation of development and activities causing accelerated stormwater runoff, is fundamental to the public health, safety and welfare and the protection of the people of Washington Township and all people of the commonwealth, their resources and the environment.
The goal of this article is to limit stormwater runoff from subdivision and other land development to predevelopment flows as indicated herein. This article is designed to:
A. 
Control accelerated runoff problems at their source by regulating activities which cause such problems.
B. 
Utilize and preserve the desirable existing natural drainage system.
C. 
Encourage recharge of groundwaters where feasible.
D. 
Maintain the existing flows and quality of streams and watercourses in Washington Township and the commonwealth.
E. 
Preserve and restore the flood-carrying capacity of the storm sewers and streams.
F. 
Provide for the design, installation and proper maintenance of all permanent stormwater management structures which are constructed in Washington Township.
Washington Township is empowered to regulate these activities by the authority of the Act of October 4, 1978, P.L. 864 (Act 167), the "Stormwater Management Act," and 32 P.S. § 680.1 et seq.
The following activities are included within the scope of this article.
A. 
Land development.
B. 
Subdivision.
C. 
Construction of new or additional impervious or semipervious surfaces (driveways, parking lots, buildings and additions thereto etc.) which increases the rate of runoff equal to or more than 0.30 cubic feet per second as calculated using the Rational Formula for a ten-year storm, except that construction creating less than 5,000 square feet of impervious surfaces shall not apply.
D. 
Diversion or piping of any natural or man-made drainage channel.
E. 
Installation of stormwater systems or appurtenances thereto, except those areas covered by PennDOT or other governmental agencies.
Permits and approvals issued pursuant to this article do not relieve the applicant of the responsibility to secure required permits or approvals for activities regulated by any other applicable code, rule, act or ordinance. If more stringent requirements concerning regulation of stormwater control are contained in the other code, rule or ordinance, the more stringent regulation shall apply.
As used in this article, the following terms shall have the meanings indicated:
CISTERN — An underground reservoir or tank for storage rainwater.
CONSERVATION DISTRICT
The Franklin County Conservation District.
CULVERT
A pipe, conduit or similar structure including appurtenant works which carries surface water.
DESIGN STORM
The magnitude of precipitation from a storm event measured in probability of occurrence (e.g., fifty-year storm) and duration (e.g., twenty-four hour), and used in computing stormwater management control systems.
DETENTION BASIN
A basin designed to detain stormwater runoff by having a controlled discharge system.
DEVELOPER
Any landowner, agent of such landowner or tenant with the permission of such landowner, who makes or causes to be made a subdivision of land or a land development, and shall include the property owner involved in activities as described in § 295-4C, D, and E.
DIVERSION TERRACE
A channel and a ridge constructed to a predetermined grade across a slope, and designed to collect and/or divert runoff from slopes which are subject to erosion.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the use of private land for stormwater management purposes.
GROUNDWATER RECHARGE
Replenishment of existing natural underground water supplies.
HYDRAULIC GRADE LINE
A line joining points whose vertical distance from the center of the cross section of the fluid flowing in a pipe are proportional to the pressure in the pipe at the point.
HYDRAULIC GRADIENT
The slope of the hydraulic grade line.
IMPERVIOUS SURFACE
A surface which retards the percolation of water into the ground, e.g., asphalt, concrete, roofs.
INFILTRATION STRUCTURES
A structure designed to direct runoff into the ground, e.g., french drains, seepage pits, seepage trench.
LAND DEVELOPMENT
A. 
The improvement of one or two or more contiguous lots, tracts or parcels of land for any purpose involving:
(1) 
A group of two or more buildings; or
(2) 
The division or allocation of land or space between or among two or more existing or prospective occupants by means of, or for the purpose of streets, common areas, leaseholds, condominiums, building groups or other features.
B. 
A subdivision of land.
LAND DISTURBANCE ACTIVITY
Any change in the existing contour of the land, e.g., grading, excavating, removal or destruction of the topsoil, trees or other vegetative cover of the land.
MAJOR PROPERTY DAMAGE
Damage to property, due to stormwater runoff, which either destroys or renders the property permanently unusable.
MUNICIPALITY
Washington Township, Franklin County, Pennsylvania.
NRCS
Natural Resources Conservation Service, U.S. Department of Agriculture.
PEAK DISCHARGE
The maximum rate of flow of water at a given point and time resulting from a specified storm event.
PRIVATE ENTITY
A partnership, corporation, homeowners' association, condominium association or any other similar association as distinguished from an individual lot owner.
RATIONAL FORMULA
A rainfall-runoff relation used to estimate peak flow, expressed by the following formula:
Q
=
CIA: Measurement of peak runoff rate in cubic feet per second
C
=
Runoff coefficient
I
=
Design rainfall intensity (in/hr) lasting for a critical time, Tc.
Tc
=
Time of concentration
A
=
Drainage area in acres
RETENTION BASIN
A basin designed to retard stormwater runoff by having a controlled subsurface discharge system.
RUNOFF
That part of precipitation which flows over the land.
SEEPAGE PIT/SEEPAGE TRENCH or FRENCH DRAIN
An area excavated in earth filled with loose stone or similar material and into which surface water is directed for infiltration into the ground.
SEEPAGE TANK
A subsurface concrete tank surrounded by stone into which surface water is directed for infiltration into the ground.
SEMIPERVIOUS SURFACE
A surface such as stone, rock or other materials which permits some vertical transmission of water.
SOIL-COVER COMPLEX METHOD
A method of runoff computation developed by NRCS, and found in its publication "Urban Hydrology for Small Watersheds," Technical Release No. 55, NRCS, Jan. 1975, Revised 1986.
STORM FREQUENCY
The number of times that a given storm event occurs or is exceeded on the average in a stated period of years.
STORM SEWER
A system of pipes or conduits which carries intercepted surface runoff, street water or drainage, but excludes domestic sewage and industrial wastes.
STORMWATER
Drainage runoff from the surface of the land resulting from precipitation or snow or ice melt.
STORMWATER MANAGEMENT PLAN
The guidelines for managing stormwater runoff as per the provisions of this article.
STORMWATER STRUCTURES
Basins, pipes, swales, terraces, etc. designed and installed to collect, transport, detain and/or retain stormwater.
SUBDIVISION
The division or redivision of a lot, tract or parcel of land by any means into two or more lots, tracts, parcels or other divisions of land including changes in existing lot lines for the purpose, whether immediate or future, of lease, transfer of ownership or building or lot development; provided, however, that the subdivision by lease of land for agricultural purposes into parcels of more than 10 acres, not involving any new street or easement of access, shall be exempt.
SWALE
A low-lying stretch of land which gathers or carries surface water runoff.
TIME OF CONCENTRATION
The time, in minutes, surface stormwater runoff takes to travel from the most distant point in the drainage basin to the point under design consideration. This time is the combined total of overland flow time and flow time in pipes or channels, if any.
A. 
Basis of calculations. Computations for determining stormwater runoff and for the design of stormwater management facilities shall be based upon the soil-cover complex method described in TR-55, Urban Hydrology for Small Watersheds; the United States Department of Agriculture, Natural Resources Conservation Service Engineering Field Manual; or TR-20, where appropriate; excepting that the Rational Method may be used for computing roof and driveway water runoff figures for seepage trench, seepage tank, seepage pit use, etc.
B. 
Rainfall frequency data. The intensity of rainfall shall be determined using the Rainfall Frequency Atlas of the United States, or other valid data as deemed suitable by the Township with a five-year base frequency; a ten-year frequency and a one-hundred-year frequency.
C. 
Maintenance of natural drainageways. All natural streams, channels, swales, drainage systems and/or areas of surface water concentration shall be maintained in their existing condition unless an exception is approved by Washington Township or an official representative thereof. All encroachment activities shall comply with Chapter 105 (Water Obstructions and Encroachments) of title 25, Rules and Regulations of the Pennsylvania Department of Environmental Resources.
D. 
Methods of stormwater runoff detention and control.
(1) 
Hereafter is a list of detention and control methods suitable for use in stormwater management systems. The selection of control methods is not limited to the ones present on this list.
(a) 
Seepage pits, trenches, seepage tanks or other infiltration structures.
(b) 
Detention and/or retention structures.
(c) 
Cisterns and underground reservoirs.
(d) 
Grass channels and vegetated strips.
(e) 
Routed flow over grass.
(f) 
Decreased impervious areas coverage.
(g) 
Porous pavement and concrete lattice block surface.
(h) 
Rooftop storage.
(i) 
Parking lot and street ponding.
(2) 
Washington Township's primary interest, where feasible and desirable, is to discharge stormwater to the subsurface.
(3) 
Certain other control methods which meet the criteria of this section will be permitted when approved by the Township or an official representative thereof.
A. 
Total system requirements. All predevelopment calculations shall be based upon existing land use features, excepting, however, that agricultural lands shall be considered as using conservation treatment or in good condition irrespective of the current use. Predevelopment stormwater runoff shall be calculated for a five-year frequency.
(1) 
Release rates from subdivisions or land developments shall be based on the runoff from the five-year predevelopment storm event.
(2) 
Storage structures shall be designed that the postdevelopment ten-year peak discharge will not exceed to predevelopment five-year peak discharge.
(3) 
All storage structures or facilities will be designed with emergency spillways sufficient to handle the one-hundred-year post development storm event without causing major property damage.
(4) 
Culverts, pipes and other water carrying structures shall be designed to handle the peak discharge from the ten-year postdevelopment storm event. All pipes shall be provided with end section or end wall.
B. 
Stormwater runoff volumes. Stormwater runoff shall be based on the following twenty-four-hour storm events; or other valid data as deemed suitable by the Township:
Storm Frequency
(years)
Storm Volume
(inches of rainfall)
2
2.9
5
3.8
10
4.8
25
5.1
100
6.4
C. 
Stormwater inlets. The maximum spacing between stormwater inlets shall be designed according to the ten-year storm flow and the capacity of the inlets, taking into account maximum allowable street flooding and drainageway capacity. When a possibility of clogging of grates, side opening, or combination inlets exists, use the capacity reduction factors shown in Table 4 applied to the theoretical capacity of the inlet.[1] The maximum amount of water that should be bypassed on to the next downstream inlet for inlets on continuous grades is 10%.
[1]
Editor's Note: Table 4 is included at the end of this chapter.
D. 
Pipes. The minimum allowable pipe diameter shall be 15 inches unless approved by the Township or an official representative thereof. Horizontal and vertical curves with radii of 100 feet or greater are allowed for all pipe sizes. Friction losses in the pipe shall be calculated using the Manning formula.[2] The minimum value for "v" in pipes shall be 3.0 feet per second. The maximum value for "v" in pipes shall be based on engineering judgment and experience. Pressure flow is permitted in storm sewers. The elevation of the hydraulic gradient shall be at least one foot below ground level. Pressure heads up to 25 feet can be used with concrete pipe with rubber gasketed joints.[3]
[2]
Editor's Note: Table 5 included at the end of this chapter provides "n" values.
[3]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. III).
E. 
Spacing of structures. The maximum allowable spacing between structures to be used for inspecting and cleaning storm sewers shall be based on the pipe size and spacing shown in Table 6.[4]
[4]
Editor's Note: Table 6 is included at the end of this chapter.
F. 
Open channels. Maximum allowable velocities of flow in swales, open channels, and ditches as relating to slope and grass cover are shown in Table 1.[5] Higher velocities require invert stabilization. If they don't present a hazard, velocity dissipators may be considered.
[5]
Editor's Note: Table 1 is included at the end of this chapter.
G. 
Where seepage pits, seepage tanks, seepage trenches and/or french drains are proposed, the developer shall include an analysis of the potential for accelerated sinkhole development in the specific geology of the site due to the concentration of water introduction to the subsurface.
H. 
Equivalent discharge. Alternative means of stormwater discharge and retention, resulting in the equivalent discharge per § 295-8A are allowable when approved by the Township Board of Supervisors.
Prior to the final approval of subdivision, land development or any activity listed in § 295-4, or the issuance of any permit, or the commencement of any land disturbance activity, the owner, subdivider, developer, or his agent shall submit a stormwater management plan to Washington Township for approval. The plan shall meet the requirements set forth herein, and shall also meet all requirements of Title 25, Rules and Regulations, Chapter 102, of the Pennsylvania Department of Environmental Resources.
The following items, where appropriate, shall be included in the plan:
A. 
General.
(1) 
General description of project.
(2) 
General description of stormwater controls both during and after development.
(3) 
Expected project time schedule, including anticipated start and completion dates.
(4) 
Training and experience of person(s) preparing the plan.
(5) 
An executed signature block by a registered professional engineer as follows: "I, __________, have prepared and hereby certify that the stormwater management plan meets all design standards and criteria of Washington Township's Stormwater Management Ordinance."
B. 
Map(s) of the project area showing:
(1) 
The location of the project relative to highways, municipalities or other identifiable landmarks.
(2) 
Existing contours at intervals of two feet. In areas of steep slopes (greater than 8%), five-foot contour intervals may be used.
(3) 
Streams, lakes, ponds, or other bodies of water within the project area or adjacent to the site which will be affected by runoff from the project.
(4) 
Other physical features, including existing drainage swales and areas of natural vegetation to be preserved.
(5) 
Location of existing overhead and underground utilities, sewers and water lines.
(6) 
Location of proposed underground utilities, sewers and water lines.
(7) 
Soil types and boundaries.
(8) 
Proposed changes to land surface and vegetative cover.
(9) 
Areas to be cut or filled.
(10) 
Proposed structures, roads, paved areas and buildings.
(11) 
Final contours at intervals of two feet. In areas of steep slope (greater than 8%) five-foot contour intervals may be used.
(12) 
Location of where water will exit the site and the means for discharging.
C. 
Stormwater management controls. All stormwater management controls must be shown on a map and described, including:
(1) 
Groundwater recharge methods such as seepage pits, seepage tanks beds or trenches. When these structures are used, the location of septic tank infiltration areas and wells must be shown, and a cross section shall be provided.
(2) 
Other control devices or methods, such as rooftop storage, semipervious paving materials, grass swales, parking lot ponding, vegetated strips, detention or retention ponds, storm sewers, etc.
(3) 
Schedule for installation of the control measures and devices.
(4) 
All calculations, assumptions and criteria used in the design of the control device or method must be shown.
(5) 
A twenty-five-foot right-of-way around all stormwater management structures and from such structures to a public right-of-way.
D. 
Maintenance program. A maintenance program for all stormwater management control facilities must be included. This program must include the proposed ownership of the control facilities and detail the financial responsibility for any required maintenance.
E. 
Priorities. The following priority process is established for facility ownership and maintenance.
(1) 
As first priority, the facilities shall be incorporated within individual lots so that the respective lot owners will own and be responsible for maintenance in accordance with recorded deed restrictions;
(2) 
As second priority, in the event the first priority cannot be achieved, ownership and maintenance shall be the responsibility of a homeowners' association. The stated responsibilities of the homeowners' association, in terms of owning and maintaining the stormwater management, facilities shall be submitted with final plans for determination of their adequacy, and upon their approval, shall be recorded with the approved plans among the land records of Franklin County, Pennsylvania. In addition, the approved plan and any deed written from said plan for a lot or lots shown herein shall contain a condition that it shall be mandatory for the owner or owners of said lot to be members of said homeowners' association; and
(3) 
The third priority, in the event the above priorities cannot be achieved, is to dedicate the facilities to the Township in accordance with this article.
A. 
Washington Township shall forward a copy of the plan to the Franklin County Conservation District for review and comment.
B. 
Washington Township or their designee shall review the plan and comments from the Franklin County Conservation District and shall recommend whether the plan be approved or disapproved.
C. 
Washington Township or their designee shall notify the applicant within 45 days from receipt of a completed plan submission of its decision.
D. 
A disapproval shall contain the reasons for disapproval and a listing of the plan deficiencies.
E. 
Failure of Washington Township or their designee to render a decision within 45 days time limit shall be deemed an approval.
A modification to an approved stormwater management plan which involves a change in control methods or techniques, or which involves the relocation or redesign of control measures, or which is necessary because soil or other conditions are not as stated on the approved application (as determined by Washington Township or their designee), shall be considered after resubmission by the plan under the procedures contained in § 295-12 of this article. Washington Township or their designee shall notify the applicant when such plan modifications are required.
The developer must submit a certification by a Pennsylvania registered professional engineer; which certificate shall certify that all elements of the approved plan have been constructed as designed and approved.
A. 
Washington Township or their designee may inspect all phases of development of the site, including but not limited to:
(1) 
Completion of preliminary site preparation, including stripping of vegetation, stockpiling of topsoil, and construction of temporary stormwater management and erosion control facilities.
(2) 
Completion of rough grading, but prior to placing topsoil, permanent drainage or other site development improvements and ground covers.
(3) 
During construction of the permanent stormwater facilities at such times as specified by Washington Township or their designee.
(4) 
Upon completion of permanent stormwater management facilities, including established ground covers and plantings.
(5) 
Upon completion of any final grading, vegetative control measures or other site restoration work done in accordance with the approved plan and permit.
B. 
It is the responsibility of the developer to notify Washington Township or their designee 48 hours in advance of the completion of each identified phase of development.
C. 
Any portion of the work which does not comply with the approved plan must be corrected by the developer. No work may proceed on any subsequent phase of the stormwater management plan, the subdivision or land development or building construction until the required corrections have been made.
D. 
If at any stage of the work, Washington Township or their designee determines that the soil or other conditions are not as stated or shown in the approved application or plan, it may refuse to approve further work and Washington Township or their designee may revoke existing permits and approvals until a revised plan is submitted and approved, as required by § 295-13 of this article.
Following construction, the developer shall submit drawings bearing the seal of a Pennsylvania registered professional engineer or land surveyor indicating the as-built improvements called for in the approved plan.
Fees covering costs to Washington Township for plan review, and inspections shall be established by resolution of Washington Township. No approval to begin any work on the project shall be issued until the requisite fees have been paid.
If it is determined that a modification to the existing stormwater management plan is required under § 295-13 of this article, a new approval shall not be issued until the additional fees have been paid by the applicant.
The developer or lot owner shall provide financial security as a construction guarantee in a form to be approved by the Township Solicitor, in an amount equal to 110% of the full cost to install the facilities required by the approved plan. The financial security shall be released only after receipt by the Township of certification and as-builts, as required.
Upon acceptance of any stormwater management facilities by Washington Township, the developer shall provide a financial security, in a form approved by the Township Solicitor for maintenance guarantees, as follows:
A. 
Construction maintenance bond. The construction maintenance bond shall be in an amount equal to 15% of the cost of the installation, and shall be used as financial security to guarantee the stability of the newly established basin and revegetation for a period of one year.
B. 
Long-term maintenance bond. The long term maintenance bond shall be in an amount equal to a figure which shall be determined by the Township to be the estimated cost of maintenance of the stormwater management facility for a period of 10 years.
When a private entity (such as a homeowners' association) retains ownership of any stormwater management facility, such entity shall be responsible for maintenance of the facility. In such case, approval of stormwater management facility plans shall be conditioned upon the private entity agreeing to be responsible for all maintenance of the stormwater management facility. Any such agreement shall be in writing, shall be in recordable form, and shall, in addition to any other terms deemed necessary by the Township, contain a provision permitting inspection at any reasonable time by Washington Township or its designee of all such facilities deemed critical to the public welfare.
When any stormwater management facility is located on an individual lot, and when maintenance thereof is the responsibility of that landowner, a description of the facility or systems and the terms of the required maintenance shall be incorporated on a plat of the property. The plat shall be recorded with the Franklin County Recorder of Deeds within 90 days following Township approval. In addition, the Township may require as a condition of approval that any deed conveying any interest in such lot contain language indicating that the conveyance is subject to an express covenant by the grantee that the grantee will maintain the stormwater management facility.
The failure of any person, individual lot owner or private entity to properly maintain any stormwater management facility shall be construed to be a violation of this article and is declared to be a public nuisance, subject to §§ 295-23 through 295-26.
Any activity conducted in violation of this article is declared to be a public nuisance.
A. 
Notice. Whenever any person shall have violated the terms of this article, the Code Enforcement Officer shall cause a written notice to be served upon the owner, applicant, developer, property manager, or other person responsible for the property or the violation, directing him to comply with all the terms of this article within seven days, or such additional period, not to exceed 30 days, as the Code Enforcement Officer shall deem reasonable, and further, the Code Enforcement Officer shall give notice to the owner, applicant, developer, property manager or other person responsible for the property or the violation that if the violation is not corrected, the municipality may correct the same and charge the landowner or other person responsible the cost thereof plus penalties as specified herein for failure to comply.
B. 
Service of notice. Such notice may be delivered by the United States mail, first class, postage prepaid, or by certified or registered mail; or by personal service; or, if the property is occupied, by posting the notice at a conspicuous place upon the subject property.
Any person who violates or permits a violation of this article shall, upon conviction in a summary proceeding brought before a Magisterial District Judge under the Pennsylvania Rules of Criminal Procedure, be guilty of a summary offense and shall be punishable by a fine of not more than $1,000, plus costs of prosecution. In default of payment thereof, the defendant may be sentenced to imprisonment for a term not exceeding 90 days. Each day or portion thereof that such violation continues or is permitted to continue shall constitute a separate offense, and each section of this article that is violated shall also constitute a separate offense. The minimum fine to be imposed is $50 per day or portion thereof for a first offense; $100 per day or portion thereof for a second offense and $500 per day or portion thereof for each subsequent offense. The Magisterial District Judge may impose a fine of more than the minimum amounts set forth above.
A. 
Corrective measures by Township; costs. In the event that the owner, developer, occupant, applicant, property manager or other person responsible fails to comply with the terms of this article within the time specified by the Code Enforcement Officer, the municipality may take any actions necessary to remove the public nuisance. The costs of removal of the violation shall be in addition to any penalties for violations for failure to comply.
B. 
Additional legal proceedings. In addition to the fines for violations, costs and penalties provided for by this article, the municipality may institute proceedings in courts of law or equity, to collect damages to require owners and/or occupants of real estate to comply with the provisions of this article.
C. 
Municipal lien. The cost of removal, fine, and penalties hereinabove mentioned may be entered by the municipality as a lien against such property in accordance with existing provisions of law.
D. 
Existing rights and remedies preserved. The collection of any penalty under the provisions of this article shall not be construed as preventing the Commonwealth of Pennsylvania, the County of Franklin, Washington Township, or any aggrieved person from proceeding in courts of law or equity to abate nuisances under existing law or to restrain, as law or in equity, a violation of this article. Moreover, it is hereby declared to be the purpose of this article to provide additional and cumulative remedies to abate nuisances.
[1]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. III).
Upon presentation of proper credentials, duly authorized representatives of Washington Township may enter at any reasonable time upon any property within the Township to investigate or to ascertain the condition of the subject property with regard to any matter regulated by this article.
Any person aggrieved by any action of the designee of Washington Township may appeal to the Board of Supervisors within 30 days of that action.
[Adopted 8-7-1995 by Ord. No. 131]
The Supervisors of the Washington Township, Franklin County, find that:
A. 
Inadequate management of accelerated stormwater runoff resulting from development throughout a watershed increases flood flows and velocities, contributes to erosion and sedimentation, overtaxes the carrying capacity of existing streams and storm sewers, greatly increases the cost of public facilities to convey and manage stormwater, undermines floodplain management and flood reduction efforts in upstream and downstream communities, reduces groundwater recharges, and threatens public health and safety.
B. 
A comprehensive program of stormwater management, including reasonable regulation of development, is fundamental to the public health, safety, welfare, and the protection of the people of the Washington Township, Franklin County, and of the commonwealth, their resources, and the environment.
The purpose of this article is to promote health, safety, and welfare within that portion of the Antietam Creek Watershed which is within the political boundaries of Washington Township, Franklin County, as such is depicted upon the attached map, which has been marked Drawing 1, and is made a part hereof,[1] by minimizing the damages described in § 295-27A of this article through provisions designed to:
A. 
Manage accelerated runoff problems at their source by regulating activities that cause these problems.
B. 
Utilize and preserve the existing natural drainage systems.
C. 
Encourage recharge of groundwater where appropriate.
D. 
Maintain existing flows and quality of streams and watercourses in Washington Township, Franklin County, and the commonwealth.
E. 
Preserve and restore the flood-carrying capacity of streams.
F. 
Provide proper maintenance of all permanent stormwater.
[1]
Editor's Note: Drawing 1 is included at the end of this chapter.
Washington Township is empowered to regulate land use activities that affect runoff by the Authority of the Act of October 4, 1978, P.L. 864 (Act 167), the Stormwater Management Act,[1] and the Act of May 1, 1933 (P.L. 103, No. 69), re-enacted and amended July 10, 1947 (P.L. 1481, No. 567), as amended, the Second Class Township Code.[2]
[1]
Editor's Note: See 32 P.S. § 680.1 et seq.
[2]
Editor's Note: See 53 P.S. § 65101 et seq.
A. 
This article shall only apply to those areas of Washington Township that are located within the Antietam Creek Watershed, as delineated on Drawing 1 of this article.[1]
[1]
Editor's Note: Drawing 1 is included at the end of this chapter.
B. 
This article shall only apply to permanent stormwater management facilities constructed as part of any of the regulated activities listed in this section. Stormwater management and erosion and sedimentation control during construction activities are specifically not regulated by this article, but shall continue to be regulated under existing laws and ordinances.
C. 
This article contains only the stormwater management performance standards and design criteria that are necessary or desirable from a watershed-wide perspective. Local stormwater management design criteria (e.g., inlet spacing, inlet type, collection system details, outlet structure design, etc.) shall continue to be regulated by Chapter 310, Subdivision and Land Development, and Ordinance No. 101,[2] for those areas that are located outside of the Antietam Creek Watershed.
[2]
Editor's Note: See Article I of this chapter.
D. 
The following activities are defined as "regulated activities" and shall be regulated by this article:
(1) 
Land development.
(2) 
Subdivision.
(3) 
Construction of new or additional impervious or semipervious surfaces in excess of 5,000 square feet (driveways, parking lots, etc.).
(4) 
Construction of new buildings or additions to existing buildings in excess of 5,000 square feet.
(5) 
Diversion or piping of any natural or man-made stream channel [see § 295-36C(3)].
(6) 
Installation of stormwater management facilities or appurtenances thereto.
(7) 
Forest management operations.
(8) 
Land disturbances in excess of 5,000 square feet but excluding those related with agricultural activities.
A. 
Any ordinance of Washington Township inconsistent with any of the provisions of this article is hereby repealed to the extent of the inconsistency only.
B. 
This article shall repeal Ordinance No. 101 only with respect to those areas of Washington Township contained within the Antietam Creek Watershed and shown on Drawing 1.
Approvals issued pursuant to this article do not relieve the applicant of the responsibility to secure required local, state and/or federal permits (such as DEP Chapter 105, 106, NPDES, etc.), or approvals for activities regulated by any other applicable code, rule, act, or ordinance.
For the purposes of this article, certain terms and words used herein shall be interpreted as follows:
A. 
Words used in present tense include the future tense; the singular number includes the plural number, and the plural number includes the singular; words of masculine gender include feminine gender; and words of feminine gender include masculine gender.
B. 
The word "includes" or "including" shall not limit the term to the specific example but is intended to extend its meaning to all other instances of like kind and character.
C. 
The word "person" includes as individual, firm, association, organization, partnership, trust, company, corporation, or any other similar entity.
D. 
The words "shall" and "must" are mandatory; the words "may" and "should" are permissive.
E. 
The words "used or occupied" include the words "intended, designed, maintained, or arranged to be used or occupied."
AGRICULTURAL ACTIVITIES
Growing crops, rotating crops, tilling of soil and grazing animals.
ALTERATION
As applied to land, a change in topography as a result of the moving of soil and rock from one location or position to another; also the changing of surface conditions by causing the surface to be more or less impervious; land disturbance.
APPLICANT
A landowner or developer who has filed an application for approval to engage in any regulated activities as defined in § 295-30 of this article.
CISTERN
An underground reservoir or tank for storing rainwater.
CONSERVATION DISTRICT
The Franklin County Conservation District.
CULVERT
A structure with appurtenant works which carries a stream under or through an embankment or fill.
DAM
An artificial barrier, together with its appurtenant works, constructed for the purpose of impounding or storing water or another fluid or semifluid, or a refuse bank, fill or structure for highway, railroad or other purposes which does or may impound water or another fluid or semifluid.
DESIGN STORM
The magnitude and temporal distribution of precipitation from a storm event measured in probability of occurrence (e.g., a five-year storm) and duration (e.g., 24-hours), used in the design and evaluation of stormwater management systems.
DETENTION BASIN
An impoundment structure designed to manage stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate.
DEVELOPER
A person, partnership, association, corporation, or other entity, or any responsible person therein or agent thereof, that undertakes any regulated activity of this article.
DEVELOPMENT SITE
The specific tract of land for which a regulated activity is proposed.
TOWNSHIP'S ENGINEER
A person duly appointed by the Board of Supervisors of Washington Township or any consultant designated by the Board of Supervisors of Washington Township to review drainage plans.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the use of private land for stormwater management purposes.
EROSION
The movement of soil particles by the action of water, wind, ice, or other natural forces.
FLOODPLAIN
Any land area susceptible to inundation by water from any natural source or delineated by applicable Department of Housing and Urban Development, Federal Insurance Administration Flood Hazard Boundary Maps as being a special flood hazard area. Also included are areas that comprise Group 13 Soils, as listed in Appendix A of the Pennsylvania Department of Environmental Protection (PaDEP) Technical Manual for Sewage Enforcement Officers (as amended or replaced from time to time by PaDEP).
FOREST MANAGEMENT OPERATIONS
All activities connected with growing and harvesting of forest products including site preparation; cultivation and logging of trees and the construction and maintenance of roads.
GROUNDWATER RECHARGE
Replenishment of existing natural underground water supplies.
IMPERVIOUS SURFACE
A surface that prevents the percolation of water into the ground.
INFILTRATION STRUCTURES
A structure designed to direct runoff into the ground (e.g., french drains, seepage pits, seepage trench).
LAND DEVELOPMENT
Any of the following activities:
(1) 
The improvement of one lot or two or more contiguous lots, tracts or parcels of land for any purpose involving:
(a) 
A group of two or more residential or nonresidential buildings, whether proposed initially or cumulatively, or a single nonresidential building on a lot or lots regardless of the number of occupants or tenure; or
(b) 
The division or allocation of land or space, whether initially or cumulatively, between or among two or more existing or prospective occupants by means of, or for the purpose of streets, common areas, leaseholds, condominiums, building groups or other features.
(2) 
A subdivision of land.
LAND DISTURBANCE
Any activity involving grading, tilling, digging, or filling of ground or stripping of vegetation or any other activity that causes an alteration to the natural condition of the land.
OPEN CHANNEL
A drainage element in which stormwater flows with an open surface. Open channels include, but shall not be limited to, natural and man-made drainageways, swales, ditches, canals, and pipes flowing partly full.
PEAK DISCHARGE
The maximum rate of stormwater runoff from a specified storm event.
PIPE
A culvert, closed conduit, or similar structure (including appurtenances) that conveys stormwater.
PMF (PROBABLE MAXIMUM FLOOD)
The flood that may be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in an area. The PMF is derived from the probable maximum precipitation (PMP) as determined on the basis of data obtained from the National Oceanographic and Atmospheric Administration (NOAA).
REGULATED ACTIVITIES
Actions or proposed actions that have an impact on stormwater runoff and that are specified in § 295-30 of this article.
RELEASE RATE
The percentage of the predevelopment peak rate of runoff from a subarea to which the postdevelopment peak of runoff must be reduced to protect downstream areas.
RETENTION BASIN
An impoundment in which stormwater is stored and not released during the storm event. Stored water may be released from the basin at some time after the end of the storm.
RETURN PERIOD
The average interval, in years, within which a storm event of a given magnitude can be expected to recur. For example, the twenty-five-year return period rainfall would be expected to recur on the average once every 25 years.
RUNOFF
Any part of precipitation that flows over the land surface.
NRCS
U.S. Department of Agriculture, Natural Resources Conservation Service.
SEDIMENTATION
The process by which mineral or organic matter is accumulated or deposited by the movement of water.
SEDIMENT BASIN
A barrier, dam, retention, or detention basin located and designed to retain rock, sand, gravel, silt, or other material transported by water.
SEEPAGE PIT/SEEPAGE TRENCH
An area of excavated earth filled with loose stone or similar coarse material, into which surface water is directed for infiltration into the ground.
SOIL-COVER COMPLEX METHOD
A method of runoff computation developed by the NRCS that is based on relating soil type and land use/cover to a runoff parameter called a curve number (CN).
STORAGE INDICATION METHOD
A reservoir routing procedure based on solution of the continuity equation (inflow minus outflow equals the change in storage) with outflow defined as a function of storage volume and depth.
STORM SEWER
A system of pipes and/or open channels that convey intercepted runoff and stormwater from other sources, but excludes domestic sewage and industrial wastes.
STORMWATER
The total amount of precipitation reaching the ground.
STORMWATER MANAGEMENT FACILITY
Any structure, natural or man-made, that, due to its condition, design, or construction, conveys, stores, or otherwise affects stormwater runoff. Typical stormwater management facilities include, but are not limited to, detention and retention basins, open channels, storm sewers, pipes, and infiltration structures.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff in the Antietam Creek Watershed adopted by Franklin County as required by the Act of October 4, 1978, P.L. 864 (Act 167), and known as the "Antietam Creek Watershed Act 167 Stormwater Management Plan."
STREAM ENCLOSURE
A bridge, culvert or other structure in excess of 100 feet in length upstream to downstream which encloses a regulated water of this commonwealth.
SUBAREA
The smallest drainage unit of a water shed for which stormwater management criteria have been established in the stormwater management plan.
SUBDIVISION
The division or redivision of a lot, tract, or parcel of land by any means into two or more lots, tracts, parcels, or other division of land including changes in existing lot lines for the purposes, whether immediate or future, or lease, partition by the court for distribution to heirs or devisees, transfer of ownership, or building or lot development; provided, however, that the subdivision by lease of land for agricultural purposes into parcels of more than 10 acres, not involving any new street or easement of access or any residential dwelling, shall be excepted.
WETLAND
Those areas ruled to be wetlands by the applicable federal or state agency.
A. 
Stormwater drainage systems shall be provided in order to permit unimpeded flow along natural watercourses, except as modified by stormwater management facilities or open channels consistent with this article.
B. 
The existing points of concentrated drainage that discharge onto adjacent property shall not be altered without the written consent and approval of the affected landowner and shall be subject to any applicable release rate criteria specified in this article.
C. 
Diffused drainage and diffused flow.
(1) 
Areas of existing diffused drainage shall be subject to any applicable release rate criteria in the general direction of existing discharge, whether proposed to be concentrated or maintained as diffused drainage areas.
(2) 
If diffused flow is proposed to be concentrated and discharged onto adjacent property, the developer must document that adequate conveyance facilities exist to safely transport the concentrated discharge, or otherwise prove that no flooding or other harm will result from the concentrated discharge.
D. 
Where a development site is traversed by watercourses other than permanent streams, a drainage easement shall be provided conforming substantially to the line of such watercourses. The terms of the easement shall prohibit excavation, the placing of fill or structures, and any alterations that may affect adversely the flow of stormwater within any portion of the easement. Also, maintenance and mowing of vegetation within the easement shall be required.
E. 
Any stormwater management facilities regulated by this article that would be located on state highway rights-of-way shall be subject to approval by the Pennsylvania Department of Transportation (PennDOT).
F. 
Any stormwater management facilities regulated by this article that would be located in or adjacent to waters of the commonwealth or wetlands shall be subject to approval by PaDEP through the joint permit application process, or, where deemed appropriate by PaDEP, the general permit process. When there is a question whether wetlands may be involved, it is the responsibility of the developer to show that the land in question cannot be classified as wetlands by the applicable federal or state agency; otherwise, approval to work in the area must be obtained from PaDEP.
G. 
When it can be shown that, due to topographic conditions, natural drainageways on the site cannot adequately provide for drainage, open channels may be constructed conforming substantially to the line and grade of such natural drainageways. Work within natural drainageways shall be subject to approval by PaDEP through the general permit process.
H. 
Sinkholes shall be protected as follows:
(1) 
Stormwater from roadways, parking lots, storm sewers, roof drains, or other concentrated runoff paths shall not be discharged directly into sinkholes.
(2) 
If increased or concentrated runoff is to be discharged into a sinkhole, including filtered discharge, a geologic assessment of the effects of such runoff on increased land subsidence and groundwater quality shall be prepared and the results submitted with the drainage plan. Such discharge shall be prohibited if Washington Township determines that the discharge poses a hazard to life, property, or groundwater resources.
A. 
Predevelopment runoff hydrographs shall be computed for both the two- and ten-year storm events. Postdevelopment runoff hydrographs for both the two- and ten-year storm events shall then be compared with the predevelopment hydrographs. If the postdevelopment hydrograph is less than or equal to the predevelopment hydrograph, then no controls are required.
B. 
Where site conditions are acceptable, infiltration practices shall be employed to control the increase in postdevelopment hydrographs. Where infiltration practices are not practical or feasible, detention facilities shall be provided solely or in combination with the infiltration facilities to achieve the following standard:
C. 
Stormwater management control facilities. The primary outlet shall be equal to the arithmetic product of the release rate percentage shown on Drawing 1 and the two-year predevelopment rate.[1] Secondary outlet control shall be provided for the ten-year storm event level and shall be controlled at the arithmetic product of the release rate percentage shown on Drawing 1 and the ten-year predevelopment rate.
[1]
Editor's Note: Drawing 1 is included at the end of this chapter.
A. 
Any stormwater management facilities required or regulated by this article shall be designed to meet the performance standards enumerated above. Compensatory stormwater management facilities shall not be permitted.
B. 
Any stormwater management facilities required or regulated by this article that conveys a postdevelopment flow of more than 19 cubic feet per second shall be designed to provide a minimum 1.0 foot of freeboard above the maximum twenty-five-year water surface elevation for postdevelopment conditions. Where storage ponding is proposed, all ponds shall include in their design an emergency spillway capable of passing the one-hundred-year postdevelopment storm event. Should any stormwater management facilities qualify as a dam under PaDEP Chapter 105, the facility shall be designed in accordance with Chapter 105 and meet the regulations of Chapter 105 concerning dam safety.
C. 
Any hydraulic capacity analysis conducted in accordance with this article shall use the following criteria to determine if adequate hydraulic capacity exists:
(1) 
Open channels must be able to convey postdevelopment runoff from a ten-year design storm within their banks at velocities that would not erode the channel bed or banks. Acceptable velocities shall be based on criteria included in the PaDEP Erosion and Sediment Pollution Control Program Manual (as amended or replaced from time to time by PaDEP).
(2) 
Open channels conveying a postdevelopment flow of more than 19 cubic feet per second shall have a minimum 1.0 foot of freeboard and not create a hazard to any persons or property.
(3) 
Any regulated activity under PaDEP Chapter 105 (e.g., culverts, bridges, outfalls, channel modifications or stream enclosures), and any work involving wetlands as described in PaDEP Chapter 105 regulations (as amended or replaced from time to time by PaDEP), shall be designed in accordance with Chapter 105 and will require a permit from PaDEP. Any other drainage conveyance facility that doesn't fall under Chapter 105 regulations must be able to convey, without damage to the drainage structure or roadway, runoff from the twenty-five-year design storm with a minimum 1.0 foot of free board measured below the lowest point along the top of the roadway. Any facility that requires a dam safety permit must be designed in accordance with PaDEP Chapter 105 regulations. Any facility located within a PennDOT right-of-way must meet PennDOT minimum design standards and permit submission requirements.
(4) 
Storm sewers must be able to convey post development runoff from a twenty-five-year design storm without surcharging inlets.
(5) 
Storm sewer inlet spacing and road cross-section design must ensure that postdevelopment runoff resulting from a ten-year design storm does not flood more than half of a driving lane.
(6) 
The maximum allowable spacing between structures to be used for inspecting and cleaning storm sewers (manholes, online inlets, risers and terminal cleanouts) shall be based on the pipe size and spacing as follows:
Size of Pipe
(inches)
Maximum Allowable Spacing
(feet)
15
400
18 to 36
500
42 to 60
700
66 or larger
Unlimited
D. 
Easements along open channels shall be provided. The minimum width of the required easement shall be equal to the width of the one-hundred-year water surface (for postdevelopment conditions) or 25 feet which ever is larger.
E. 
In subareas where individual stormwater management facilities would be provided for each development site, the individual stormwater management facilities shall be designed to ensure that the postdevelopment peak discharge at the mouth of the subarea does not exceed the arithmetic product of the applicable release rate, specified in Appendix 1 and on Drawing 1 of this article,[1] and the predevelopment peak discharge at the mouth of the subarea.
[1]
Editor's Note: Appendix 1 and Drawing 1 are included at the end of this chapter.
F. 
For development sites that would be located in two or more subareas, the applicable release rate for the portions of the site located in different subareas shall be based on natural subarea drainage boundaries. The natural drainage boundaries between subareas shall not be modified, nor shall drainage from a development site be diverted or otherwise conveyed from one subarea to another subarea, except where runoff naturally crosses subarea drainage boundaries.
G. 
Regional or subregional stormwater management facilities. For certain areas within the watershed, it may be more cost effective to provide one stormwater management facility for an entire subarea, group of subareas, or portions of a subarea incorporating more than one development site than to provide an individual stormwater management facility for each development site. The initiative and funding for any regional or subregional stormwater management alternatives are the responsibility of prospective developer(s). The design of any regional stormwater management facilities must assume development of the entire area that would drain to the regional facility. The type and amount of development that the developer(s) must consider shall be either based on current zoning or on projections established by the Franklin County Planning commission, whichever results in a greater amount of imperviousness. The peak outflow from a regional stormwater management facility would be determined on a case-by-case basis using the Penn State Runoff Method (PSRM), as developed for the Antietam Creek Watershed Act 167 Stormwater Management Plan. When regional or subregional stormwater management facilities are utilized, the effect of phased growth on stormwater runoff flows must be corrected. At no time from the initial phase through ultimate development shall the peak runoff flows exceed the predevelopment peak multiplied by the applicable release rate.
H. 
Capacity improvements. If the developer could prove that it would be feasible to provide capacity improvements to relieve the capacity deficiency in the existing drainage network, then adequate capacity improvements could be provided by the developer in lieu of stormwater management facilities on the development site. Any capacity improvements would be designed based on development of all areas tributary to the improvements and the capacity criteria specified in this article. The type and amount of development that the developer must consider shall be either based on current zoning or on projections established by the Franklin County Planning Commission, whichever results in a greater amount of imperviousness. It shall be assumed that all new development upstream of a proposed capacity improvement would implement applicable stormwater management techniques consistent with this article.
I. 
Adequate erosion protection shall be provided along all open channels and at all points of discharge.
J. 
The design of all stormwater management facilities shall incorporate sound engineering principles and practices. Washington Township shall reserve the right to disapprove any design that would result in the occurrence or perpetuation of an adverse hydrologic or hydraulic condition within the watershed.
A. 
Any stormwater runoff calculations involving drainage areas greater than 20 acres, including on- and off-site areas, shall use any generally accepted calculation technique that is based on the NRCS soil-cover complex method. Table I below summarizes acceptable computation methods. All methods shall be selected by the design professional based on the individual limitations and suitability of each method for a particular site. The Washington Township Engineer may approve the use of the Rational Method to estimate peak discharges from drainage areas that contain less than 20 acres.
Table I
Acceptable Computation Methodologies For Stormwater Management Plan
Method
Developer
Applicability
TR-20 (or commercial package based on TR-20)
USDA NRCS
Applicable where use of full hydrology computer model is desirable or necessary
TR-55 (or commercial computer package based on TR-55)
USDA NRCS
Applicable for land development plans within limitations described in TR-55
HEC-1
U.S. Army Corps of Engineers
Applicable where use of full hydrologic computer model is desirable or necessary
PSRM
Penn State Univ.
Applicable where use of a hydrologic computer model is desirable or necessary; simpler than TR-20 or HEC-1
Rational Method (or commercial computer package based on the Rational Method)
Emil Kuichling (1889)
For sites less than 20 acres, or as approved by the Township's Engineer
Other methods
Varies
Other computation methodologies approved by the Township's Engineer
B. 
The design of any stormwater detention facilities intended to meet the performance standards of this article shall be verified by routing the design storm hydrograph using the storage-indication method. For drainage areas greater than 20 acres in size, the design storm hydrograph shall be computed using a calculation method that produces a full hydrograph. The Township's Engineer may approve the use of any generally accepted full hydrograph approximation technique which uses a total volume that is consistent with the volume from a method that produces a full hydrograph.
C. 
All calculations consistent with this article using the soil-cover complex methods shall use the appropriate design rainfall depths in inches for the various return period storms presented in Table II of this article. If a hydrologic computer model such as PSRM or HEC-1 is used for stormwater runoff calculations, then the duration of rainfall shall be 24 hours.
Table II
Antietam Creek Watershed Rainfall
Intensity/Duration — Frequency
Storm Event
(years)
Duration
(hours)
1
2
3
6
12
24
2
1.18
1.35
1.55
1.75
2.00
2.38
10
2.11
2.55
2.80
3.25
3.75
4.45
25
2.49
2.95
3.25
3.85
4.60
5.20
50
2.79
3.50
3.75
4.40
5.15
5.78
100
3.08
3.70
4.10
4.75
5.55
6.32
D. 
All calculations using the Rational Method shall use rainfall intensities consistent with appropriate times of concentration for overland flow and return periods from Table II in § 295-37C of this article. Times of concentration for overland flow shall be calculated using the methodology presented in Chapter 3 of Urban Hydrology for Small Watershed, NRCS, TR-55 (as amended or replaced from PennDOT Design Manual #2, Region 4 for watershed tributary to the East Branch and Region 3 for watershed tributary to the West Branch). Times of concentration for channel and pipe flow shall be computed using Manning's equation.[1]
[1]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. III).
E. 
Runoff curve numbers (CN) for both existing and proposed conditions to be used in the soil-cover method shall be obtained from Table 2-2 of the USDA NRCS TR-55, except that all agricultural predevelopment conditions shall be considered good with the best conservation practices assumed to be employed.
F. 
Runoff coefficients (c) for both existing and proposed conditions for use in the Rational Method shall be obtained from Table 4.2 of the DEP Erosion and Sediment Pollution Control Program Manual and shall be subject to the approval of the Township's Engineer.
G. 
Where uniform flow is anticipated, the Manning equation shall be used for hydraulic computations, and to determine the capacity of open channels, pipes, and storm sewers. Values of roughness coefficient "n" for use in the Manning formula are shown in Table V. Where nonuniform flow is anticipated, the hydraulic effects of "backwater" caused by hydraulic obstructions (e.g., culverts, bridges, dams, reservoirs, etc.) shall be evaluated using the standard step method for determining water surface profiles.
H. 
Outlet structures for stormwater management facilities shall be designed to meet the performance standards of this article using any generally accepted hydraulic analysis technique or method approved by the Township's Engineer.
Table III
Inlet Capacity Reduction Factors Assuming Partial Clogging
Condition
Inlet Type
Reduction Factor*
Sump
Side Opening
0.80
Sump
Grate
0.50
Sump
Combination
0.65
Continuous Grade
Side Opening
0.80
Continuous Grade
Side Opening with Deflector
0.75
Continuous Grade
Longitudinal Bars
0.60
Continuous Grade
Transverse Bars
0.50
Continuous Grade
Combination
0.60
* Percentage of theoretical capacity
Table IV
"n" Values For Manning Formula
Type of Pipe
"n" Value*
Asbestos cement
0.013
Concrete culvert pipe
0.013
Concrete sewer pipe
0.013
Cast iron
0.013
Corrugated metal (plain)
0.024
Corrugated metal (coated)
0.021
Plastic
0.011
Vitrified clay
0.013
* Adjustments for specific conditions shall be based on engineering experience and judgment and submitted to the Township Engineer for approval.
A. 
For any of the activities regulated by this article, the final approval of subdivision and/or land development plans, the issuance of any building or occupancy permit, or the commencement of any land disturbance activity may not proceed until the property owner or developer or his/her agent has received written approval of a drainage plan from Washington Township.
B. 
The drainage plan shall be designed and certified by individuals registered in the Commonwealth of Pennsylvania to perform such duties.
A. 
Any regulated activity that would create 5,000 square feet or less of impervious area is exempt from the provisions of this article. This criteria shall apply to the total development even if development is to take place in phases. The developer shall be responsible to ensure that exempted activities shall maintain sound building and construction practices such that the quantity, velocity and direction of the resulting stormwater runoff will adequately protect hearth, safety, or other property from possible injury.
B. 
Land disturbance associated with existing one and two-family dwellings, subject to conditions described in Subsection A of this section.
C. 
Use of land for gardening for home consumption.
D. 
Agricultural activities when operated in accordance with a conservation plan or erosion and sedimentation control plan prepared by the conservation district are specifically exempt from complying with the requirements of this article. The construction of buildings, parking lots or any activity that results in more than 5,000 square feet of impervious surface shall comply with the requirements of this article.
E. 
No exemption shall be provided for regulated activities as defined in § 295-30E and F of this article.
The drainage plan shall consist of all applicable calculations, maps, and plans. A note on the maps shall refer to the associated computations and erosion and sedimentation control plans by title and date. The cover sheet of the computations and erosion and sedimentation control plan shall refer to the associated maps by title and date. All drainage plan materials shall be submitted to the Township's Engineer in a format that is clear, concise, legible, neat, and well organized; otherwise, the drainage plan shall be disapproved and returned to the applicant. The following items shall be included in the drainage plan:
A. 
General.
(1) 
General description of project.
(2) 
General description of permanent stormwater management techniques, including construction specifications of the materials to be used for stormwater management facilities.
(3) 
Complete hydrologic, hydraulic, and structural computations for all stormwater management facilities.
B. 
Map(s) of the project area shall be submitted on twenty-four-inch by thirty-six-inch or thirty-inch by forty-two-inch sheets and shall be prepared in a form that meets the requirements for recording at the office of the Recorder of Deeds of Franklin County. The contents of the map(s) shall include, but are not limited to:
(1) 
The location of the project relative to highways, municipalities or other identifiable landmarks.
(2) 
Existing contours at intervals of two feet. In areas of steep slopes (greater than 15%), five-feet contour intervals may be used.
(3) 
Existing streams, lakes, ponds, or other bodies of water within the project area.
(4) 
Other physical features including flood hazard boundaries, sinkholes, streams, existing drainage courses, areas of natural vegetation to be preserved, and the total extent of the upstream area draining through the site.
(5) 
The locations of all existing and proposed utilities, sanitary sewers, and water lines within 50 feet of property lines.
(6) 
Soil names and boundaries.
(7) 
Proposed changes to the land surface and vegetative cover, including the type and amount of impervious area that would be added.
(8) 
Proposed structures, roads, paved areas, and buildings.
(9) 
Final contours at intervals of two feet. In areas of steep slopes (greater than 15%), five-foot contour intervals may be used.
(10) 
The name of the development, the name and address of the owner of the property, and the name of the individual preparing the plan and a certification that the drainage plan meets all the design standards and criteria of the Antietam Creek Watershed Act 167 Stormwater Management Ordinance.
(11) 
The date of submission.
(12) 
A graphic and written scale of one inch equals no more than 50 feet; for tracts of 20 acres or more, the scale shall be one inch equals no more than 100 feet.
(13) 
A North arrow.
(14) 
The total tract boundary and size with distances marked to the nearest foot and bearings to the nearest degree.
(15) 
Existing and proposed land use(s).
(16) 
A key map showing all existing man-made features beyond the property boundary that would be affected by the project.
(17) 
Horizontal and vertical profiles of all open channels, including hydraulic capacity.
(18) 
Overland drainage paths.
(19) 
A twenty-foot access easement to all stormwater management facilities that provides ingress from and egress to a public right-of-way shall be provided. The easement shall be shown on the subdivision or land development plan.
(20) 
A note on the plan indicating the location and responsibility for maintenance of stormwater management facilities that would be located off site. All off-site facilities shall meet the performance standards and design criteria specified in this article.
(21) 
A statement, signed by the landowner, acknowledging the stormwater management system to be a permanent fixture that can be altered or removed only after approval of a revised plan by Washington Township.
C. 
Supplemental information.
(1) 
A written description of the following information shall be submitted.
(a) 
The overall stormwater management concept for the project.
(b) 
Stormwater runoff computations as specified in this article.
(c) 
Stormwater management techniques to be applied both during and after development.
(d) 
Expected project time schedule.
(2) 
A soil erosion sedimentation control plan, including all reviews and approvals, as required by PaDEP.
(3) 
A geologic assessment of the effects of runoff on sinkholes as specified in this article.
(4) 
The effect of the project (in terms of runoff volumes and peak flows) on adjacent properties and on any existing municipal stormwater collection system that may receive runoff from the project site.
(5) 
A declaration of adequacy and highway occupancy permit from the PennDOT District Office when utilization of a PennDOT storm drainage system is proposed.
D. 
Stormwater management facilities.
(1) 
All stormwater management facilities must be located on a map and described in detail.
(2) 
When groundwater recharge methods such as seepage pits, beds or trenches are used, the locations of existing and proposed septic tank infiltration areas and wells must be shown.
(3) 
All calculations, assumptions, and criteria used in the design of the stormwater management facilities must be shown.
For all activities regulated by this article, the steps below shall be followed for submission. For any activities that require a PaDEP joint permit application and are regulated under Chapter 105 (Dam Safety and Waterway Management) or Chapter 106 (Floodplain Management) of PaDEP's rules and regulations, require a PennDOT highway occupancy permit, or require any other permit under applicable state or federal regulations, the permit(s) shall be part of the plan.
A. 
The drainage plan shall be submitted by the developer as part of a subdivision preliminary plan or a land development plan submission for the regulated activity.
B. 
Six copies of the drainage plan and calculations shall be submitted to the Township no less than 10 calendar days prior to the next regular monthly meeting of the Washington Township Planning Commission. The Township will distribute one copy to the Township's Consulting Engineer and one copy to the Washington Township Planning Commission.
A. 
The Washington Township Planning Commission shall review the drainage plan for consistency with this article and shall make its recommendations to the Board of Supervisor of Washington Township within 45 days after official submission. The Washington Township Planning Commission shall require receipt of a complete plan, as specified in this article.
B. 
The Township's Engineer shall review the drainage plan for any subdivision or land development against Chapter 310, Subdivision and Land Development, provisions not superseded by this article.
C. 
For activities regulated by this article, the Washington Township Engineer shall notify the Township and developer, in writing, within 90 calendar days after official submission, whether the drainage plan is consistent with this article. Should the drainage plan be determined to be consistent with the this article, the Township's Engineer will forward an approval letter to the Township who will notify the developer. Should the drainage plan be determined to be inconsistent with this article, the Township's Engineer will forward a disapproval letter to the Township and developer citing the reason(s) for the disapproval. Any disapproved drainage plan may be revised by the developer and resubmitted consistent with this article.
D. 
For regulated activities specified in § 295-30C and D of this article, the Washington Township Engineer shall notify the Township's Code Enforcement Officer, in writing, within a time frame consistent with other Township ordinances, whether the drainage plan is consistent with this article and forward a copy of the approval/disapproval letter to the developer. Any disapproved drainage plan may be revised by the developer and resubmitted consistent with this article.
E. 
For regulated activities requiring a PaDEP joint permit application, the Township's Engineer shall notify PaDEP whether the drainage plan is consistent with this article and forward a copy of the review letter to the Washington Township Planning Commission and Board of Supervisors of Washington Township and the developer. PaDEP may consider the Township's Engineer review comments in determining whether to issue a permit.
F. 
The Board of Supervisors of Washington Township shall not approve any subdivision or land development for regulated activities specified in § 295-30A and B of this article if the drainage plan has been found to be inconsistent with this article or without considering the comments of the Franklin County Planning Commission, the Franklin County Conservation District and the Washington Township Planning Commission. All required permits from PaDEP must be obtained prior to approval.
G. 
Washington Township's Code Enforcement Officer shall not issue a building permit for any regulated activity specified in § 295-30C and D of this article if the drainage plan has been found to be inconsistent with this article, as determined by the Township Engineer. All required permits from PaDEP must be obtained prior to issuance of a building permit.
H. 
The developer shall be responsible for completing an as-built survey of all stormwater management facilities included in the approved drainage plan. The as-built survey and an explanation of any discrepancies with the design plan shall be submitted to the Township's Engineer for final approval.
I. 
The approval by the Board of Supervisors of Washington Township of a drainage plan shall be valid for a period not to exceed one year. This one-year time period shall commence on the date that the Board of Supervisors of Washington Township approved the drainage plan. If stormwater management facilities included in the approved drainage plan have not been constructed, or if an as-built survey of these facilities has not been approved within this one-year time period, then Washington Township may consider the drainage plan disapproved and may revoke any and all permits. Drainage plans that are considered disapproved by the Board of Supervisors of Washington Township shall be resubmitted in accordance with § 295-44 of this article.
A. 
A modification to a submitted drainage plan for a development site that involves a change in stormwater management facilities or techniques, or that involves the relocation or redesign of stormwater management facilities, or that is necessary because soil or other conditions are not as stated on the drainage plan (as determined by the Township's Engineer), shall require a resubmission of the modified drainage plan consistent with § 295-41 of this article and be subject to review as specified in § 295-42 of this article.
B. 
A modification to an already approved or disapproved drainage plan shall be submitted to the Township, accompanied by the applicable review fee.
A disapproved drainage plan may be resubmitted, with the revisions addressing the Township's Engineer concerns documented in writing, to the Township's Engineer in accordance with § 295-41 of this article and be subject to review as specified in § 295-42 of this article. The applicable review fee must accompany a resubmission of a disapproved drainage plan.
A. 
The Township's Engineer or his assignee shall inspect all phases of the installation of the permanent stormwater management facilities including, but not limited to:
(1) 
Completion of preliminary site preparation including stripping or vegetation, stockpiling of topsoil, and construction of temporary stormwater management and erosion control facilities.
(2) 
Completion of rough grading, but prior to placing topsoil, permanent drainage or other site development improvements and ground covers.
(3) 
During construction of the permanent stormwater facilities at such times specified by Township's Engineer or their designee.
(4) 
Upon completion of permanent stormwater management facilities, including established ground covers and plantings.
(5) 
Upon completion of any final grading, vegetative control measures or other site restoration work done in accordance with the approved plan and permit.
B. 
It shall be the responsibility of the developer to notify the Township 48 hours in advance of the completion of each identified phase of construction so that it can be inspected.
C. 
During any stage of the work, if the Township's Engineer or his assignee determines that the permanent stormwater management facilities are not being installed in accordance with the approved stormwater management plan, the Township's Code Enforcement Officer shall revoke any existing permits until a revised drainage plan is submitted and approved, as specified in this article.
The fees required by this article are the Washington Township review fees. Washington Township review fee shall be established by resolution by the Board of Supervisors Washington Township to defray any review and inspection costs incurred by Washington Township and/or the Township's Engineer. All fees shall be paid by the applicant. Permits to begin any work on any project shall not be issued until the required fees have been paid. The fee schedule may be amended by the Supervisors from time to time.
The fees required by this article shall at a minimum cover:
A. 
The review of the drainage plan by the Township's Engineer.
B. 
The site inspection.
C. 
The inspection of stormwater facilities and drainage improvements during construction.
D. 
The final inspection upon completion of the stormwater management facilities and drainage improvements presented in the drainage plan.
E. 
Any additional work required to enforce any permit provisions regulated by this article, correct violations, and assure proper completion of stipulated remedial actions.
F. 
Legal fees.
G. 
Engineering Fees.
A. 
Following final approval of the as-built survey by the Washington Township Supervisors, the developer shall dedicate the permanent stormwater management facilities to the specific entity responsible for the overall maintenance and control of the stormwater management facilities. Any such designated entity, other than Washington Township, shall be approved by Washington Township as an acceptable and duly authorized organization to carry on the responsibility and obligations of maintenance upkeep and be bound by this article. Such responsible entities shall be set up as legal organizations bound by the laws of the Commonwealth of Pennsylvania and Washington Township. In addition to Washington Township ownership, such entities can be homeowners' associations, corporations, or individual lot owners.
B. 
In instances where the permanent control facilities are owned by a private entity (such as a homeowners' association), such entity shall be responsible for maintenance of the facility. In such case, approval of stormwater management facility plans shall be conditioned upon the private entity agreeing to be responsible for all maintenance of the stormwater management facility. Any such agreement shall be in writing, shall be in recordable form, and shall, in addition to any other terms deemed necessary by the Township, contain a provision permitting inspection at any reasonable time by Washington Township or its designee of all such facilities deemed critical to the public welfare. Such an agreement shall be executed by the entity responsible for the maintenance and the developer and shall be submitted by the developer to the Township for approval.
C. 
In instances when any stormwater management facility is located on an individual lot, and when maintenance thereof is the responsibility of that landowner, a description of the facility or systems and the terms of the required maintenance shall be incorporated on a plat of the property. The plat shall be recorded with the Franklin County Recorder of Deeds within 90 days following Township approval. In addition, the Township may require as a condition of approval that any deed conveying any interest in such lot contain language indicating that the conveyance is subject to an express covenant by the grantee that the grantee will maintain the stormwater management facility.
D. 
In all instances, the developer shall post financial security in an amount sufficient to cover the present worth of maintenance of the facilities for a ten-year period. The financial security shall be based on the estimated annual maintenance cost for the facilities submitted by the developer and prepared by a professional engineer/surveyor licensed as such in this commonwealth and certified by such engineer/surveyor to be a fair and reasonable estimate of such cost. Washington Township, upon the recommendation of the Township's Engineer, may refuse to accept such estimate for good cause shown. If the developer and the Township are unable to agree upon an estimate, then the estimate shall be recalculated and recertified by another professional engineer/surveyor licensed as such in this commonwealth and chosen mutually by the Township and the developer. The estimate certified by the third engineer/surveyor shall be presumed fair and reasonable and shall be the final estimate. In the event that a third engineer/surveyor is so chosen, fees for the services of said engineer/surveyor shall be paid equally by Washington Township and the developer.
E. 
Financial security shall be posted with a bonding company or federal or commonwealth chartered lending institution chosen by the party posting the financial security, provided said bonding company or bonding institution is authorized to conduct said business within the commonwealth. In lieu of a bond, the developer may deposit cash or other acceptable securities with Washington Township or with a bank or trust company to guarantee performance of said contract and to secure completion of the improvements under an escrow agreement approved by Washington Township's Solicitor and the Board of Supervisors of Washington Township. The amount of the bond or other guarantee shall be sufficient to cover the cost of required improvements as estimated by the Engineer. The escrow agent for the deposits of such cash or securities shall be designated and selected by the Board of Supervisors of Washington Township.
F. 
Such bond or other security shall provide for and secure to the public, the maintenance cost of the facilities which may be required for a ten-year period.
G. 
Federal or commonwealth chartered lending institutions irrevocable letters of credit and restrictive or escrow accounts in such lending institutions are acceptable forms of financial security which may be utilized by a developer to comply with the requirements of this article.
H. 
If Washington Township determines at any time that any permanent stormwater management control facilities have been eliminated, altered or improperly maintained, the responsible entity shall be advised of corrective measures required and given a reasonable period of time to take necessary action. If such action is not taken by the responsible entity, Washington Township may cause the work to be done and assess all costs plus 10% against the property of the responsible entity or collect same by an appropriate action of law.
I. 
The failure of any person, individual lot owner or private entity to properly maintain any stormwater management facility shall be construed to be a violation of this article and is declared to be a public nuisance, subject to §§ 295-49 through 295-52.
Upon presentation of proper credentials, duly authorized representatives of Washington Township may enter at reasonable times upon any property within Washington Township to investigate or ascertain the condition of the subject property in regard to any aspect regulated by this article.
In the event that a person fails to comply with the requirements of this article, or fails to conform to the requirements of any permit issued hereunder, Washington Township shall provide written notification of the violation(s). Such notification shall set forth the nature of the violation(s) and establish a time limit for correction of these violation(s). Failure to fully comply within the time specified shall subject such person to the penalty provisions of this article. All such penalties shall be deemed cumulative and resort to such by Washington Township shall not prevent Washington Township from pursing any and all other remedies. It shall be the responsibility of the owner and developer of the real property on which any regulated activity is proposed to occur, is occurring, or has occurred, to comply with the terms and conditions of this article.
Any person who violates or permits a violation of this article shall, upon conviction in a summary proceeding brought before a Magisterial District Judge under the Pennsylvania Rules of Criminal Procedure, be guilty of a summary offense and shall be punishable by a fine of not more than $1,000, plus costs of prosecution. In default of payment thereof, the defendant may be sentenced to imprisonment for a term not exceeding 90 days. Each day or portion thereof that such violation continues or is permitted to continue shall constitute a separate offense, and each section of this article that is violated shall also constitute a separate offense. The minimum fine to be imposed is $50 per day or portion thereof for a first offense; $100 per day or portion thereof for a second offense and $500 per day or portion thereof for each subsequent offense. The Magisterial District Judge may impose a fine of more than the minimum amounts set forth above.
[1]
Editor's Note: Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. III).
A. 
Nuisance. Any activity conducted in violation of the provisions of this article or of any regulations adopted under this article is hereby declared to be a public nuisance.
B. 
Lawsuits. Suits to restrain, prevent or abate violations of this article may be instituted in equity or at law by the Township or by any aggrieved person. Except in cases of emergency where, in the opinion of the court, the circumstances of the case require immediate abatement of the unlawful conduct, the court may, in its decree, fix a reasonable time during which the person responsible for the unlawful conduct shall correct or abate the same. The expense of such proceedings shall be recoverable from the violator in such a manner as may now or hereafter be provided by law.
C. 
Remedies cumulative. The collection of any penalty under the provisions of this article shall not be construed as stopping the commonwealth, the County of Franklin, Washington Township, or any aggrieved person from proceeding in courts of law or equity to abate nuisances under existing law or to restrain at law or in equity, violation of this article. It is the purpose of this article to provide additional and cumulative remedies to abate nuisances.
D. 
Corrective measures by Township; costs. In the event that the owner, developer, occupant, applicant, property manager or other person responsible fails to comply with the terms of this article within the time specified by the Code Enforcement Officer, the municipality may take any actions necessary to remove the public nuisance. The costs of removal of the violation shall be in addition to any penalties for violations for failure to comply.
E. 
Municipal lien. The cost of removal, fine, and penalties hereinabove mentioned may be entered by the municipality as a lien against such property in accordance with existing provisions of the law.
Any person aggrieved by any action of the Township's Engineer may appeal to the Board of Supervisors of Washington Township within 30 days of that action.
The various headings used throughout this article are intended only as an aid in its organization, in order to facilitate ease of reading, and are not to be considered a substantive part of this article.