This chapter shall be known and may be cited as the "Upper Hanover Township Stormwater Management Ordinance."
The Board of Supervisors hereby finds that:
Inadequate management of accelerated runoff of stormwater resulting from development throughout a watershed increases flood flows and velocities, contributes to erosion and sedimentation, changes the natural hydrologic patterns, destroys aquatic habitat, elevates aquatic pollutant concentrations and loadings, 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.
A comprehensive program of stormwater management, including reasonable regulation of development and activities causing accelerated erosion and loss of natural infiltration, is fundamental to public health, safety, and welfare and the protection of the people of the municipality and all of the people of the commonwealth, their resources, and the environment.
Stormwater can be an important resource by providing groundwater recharge for water supplies and base flow of streams, which also protects and maintains surface water quality.
Public education on the control of pollution from stormwater is an essential component in successfully addressing stormwater.
Federal and state regulations require certain municipalities to implement a program for stormwater controls. These municipalities are required to obtain a permit for stormwater discharges from their separate storm sewer systems under the National Pollutant Discharge Elimination System (NPDES).
Nonstormwater discharges to municipal separate storm sewer systems can contribute to pollution of waters of the commonwealth.
The purpose of this chapter is to promote the public health, safety, and welfare within Upper Hanover Township by minimizing the damages and maximizing the benefits described in § 415-2 of this chapter by provisions designed to:
Manage stormwater runoff impacts at their source by regulating activities which cause stormwater problems.
Utilize and preserve the desirable existing natural drainage systems.
Encourage infiltration of stormwater, where appropriate, to maintain groundwater recharge, to prevent degradation of surface and groundwater quality, and to otherwise protect water resources.
Maintain the existing flows and quality of streams and watercourses in the municipality and the Commonwealth.
Preserve and restore the flood-carrying capacity of streams.
Provide for proper maintenance of all permanent stormwater management BMPs that are implemented in the municipality.
Provide review procedures and performance standards for stormwater planning, design, and management.
Manage stormwater impacts close to the runoff source which requires a minimum of structures and relies on natural processes.
Meet legal water quality requirements under state law, including regulations at 25 Pa. Code § 93.4(a) to protect and maintain "existing uses" and maintain the level of water quality to support those uses in all streams, and to protect and maintain water quality in "special protection" streams.
Prevent scour and erosion of streambanks and streambeds.
Provide standards to meet the NPDES permit requirements.
Upper Hanover Township is empowered to regulate these activities by the authority of the Act of October 4, 1978, P.L. 864 (Act 167). 32 P.S. § 680.1 et seq., as amended, the Storm Water Management Act, Act 247, the Pennsylvania Municipalities Planning Code of July 31, 1968, P.L. 805; 53 P.S. § 10101, as reenacted and amended.
This chapter shall only apply to all areas of the municipality. The following activities are defined as regulated activities and shall be governed by this chapter:
Construction of new or additional impervious surfaces (driveways, parking lots, etc.).
Construction of new buildings or additions to existing buildings.
Diversion or piping of any natural or man-made stream or channel.
Installation of stormwater systems or appurtenances thereto.
Regulated earth-disturbance activities.
Any earth-disturbance activities or any activities that involve the alteration or development of land in a manner that may affect stormwater runoff onto adjacent property.
Impervious cover. Any proposed regulated activity (except those defined in § 415-5E through H) that would create additional impervious cover is exempt from the drainage plan preparation provisions of this chapter only as provided in Table 1. If a site has previously received an exemption and is proposing additional development such that the total impervious cover on the site exceeds the amounts in Table 1, the total impervious cover on the site, proposed since the original ordinance date, must meet the provisions of this chapter.
The date of the municipal adoption of this chapter shall be the starting point from which to consider tracts as "parent tracts" in which future subdivisions and respective impervious area computations shall be cumulatively considered.
For development taking place in stages, the entire development plan must be used in determining conformance with these criteria.
Additional impervious cover shall include, but not be limited to, additional indoor living spaces, decks, patios, garages, driveways, storage sheds and similar structures, and roof, parking, or driveway areas, and any new streets and sidewalks constructed as part of or for the proposed regulated activity.
Any additional areas proposed initially to be gravel, crushed stone, porous pavement, etc., shall be assumed to be impervious for the purposes of comparison to the exemption criteria. Any existing gravel, crushed stone, or hard-packed soil areas on a site shall be considered as pervious cover for the purpose of exemption evaluation.
Prior drainage plan approval. Any regulated activity for which a drainage plan was previously prepared as part of a subdivision or land development proposal that received preliminary plan approval from the municipality prior to the effective date of this chapter is exempt from the drainage plan preparation provisions of this chapter, except as cited in § 415-6D, provided that the approved drainage plan included design of stormwater facilities to control runoff from the site currently proposed for regulated activities consistent with ordinance provisions in effect at the time of approval, and the approval has not lapsed under the Municipalities Planning Code.
If significant revisions are made to the drainage plan after both the preliminary plan approval and the effective date of this chapter, preparation of a new drainage plan, subject to the provisions of this chapter, shall be required.
Significant revisions would include a change in control methods or techniques, relocation or redesign of control measures, or changes necessary because soil or other conditions are not as stated on the original drainage plan.
Activities associated with § 415-5H shall be exempt from the drainage plan preparation requirements of this chapter unless the municipality determines that the activity could create a new or relocated concentrated drainage discharge onto adjacent property. Agricultural plowing and tilling as may be covered by § 415-5H are exempt from the drainage plan preparation requirements of this chapter.
These exemptions shall not relieve the applicant from implementing such measures as are necessary to protect health, safety, property, and state water quality requirements. These measures include adequate and safe conveyance of stormwater on the site and as it leaves the site. These exemptions do not relieve the applicant from the responsibility to secure permits or approvals for activities regulated by any other applicable code, rule, act, or ordinance.
Approvals issued pursuant to this chapter 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.
Notwithstanding any provisions of this chapter, including exemption and waiver provisions, any landowner and any person engaged in the alteration or development of land which may affect stormwater runoff characteristics shall implement such measures as are reasonably necessary to prevent injury to health, safety, or other property. Such measures shall include such actions as are required to manage the rate, volume, direction, and quality of resulting stormwater runoff in a manner which otherwise adequately protects health and property from possible injury.