(a) Applicants proposing regulated activities in the municipality which do not fall under the exemption criteria shown in § 1043.06 shall submit a stormwater management site plan consistent with this chapter and the applicable watershed stormwater management plan to the municipality for review. The stormwater management criteria of this chapter shall apply to the total proposed development even if development is to take place in stages.
(b) No regulated activity within the municipality shall commence until the municipality issues approval of a SWM plan, which demonstrates compliance with the requirements of this chapter.
(c) The applicant is required to design the site to minimize surface discharge of stormwater and the creation of impervious surfaces in order to maintain, as much as possible, the natural hydrologic regime.
(d) The SWM site plan must be designed consistent with the sequencing provisions of § 1043.15 to ensure maintenance of the natural hydrologic regime, to promote infiltration, and to protect groundwater and surface water quality and quantity. The SWM site plan designer must proceed sequentially in accordance with §§ 1043.12 through 1043.21.
(e) Stormwater drainage systems shall be designed in order to preserve natural flow conditions to the maximum extent practicable.
(f) Existing drainage discharge onto adjacent property shall not be altered in any manner without written permission, and a maintenance access agreement with, the affected property owner(s). Such discharge shall be subject to any applicable discharge criteria specified in this chapter and still must meet the requirements of Act 167, being 32 P.S. §§ 680.1 et seq.
(g) Areas of existing diffused drainage discharge, whether proposed to be concentrated or maintained as diffused drainage areas, shall be subject to any applicable discharge criteria in the general direction of existing discharge, except as otherwise provided by this chapter. If diffused drainage discharge is proposed to be concentrated and discharged onto adjacent property, the applicant must document that adequate downstream conveyance facilities exist to safely transport the concentrated discharge or otherwise prove that no erosion, sedimentation, flooding or other impacts will result from the concentrated discharge.
(h) Where a development site is traversed by a stream, drainage easements of 25 feet shall be provided on either side of, and conform to the line of such streams.
(i) Minimization of impervious surfaces and infiltration of runoff through seepage beds, infiltration trenches and the like, is encouraged where soil conditions permit in order to reduce the size or eliminate the need for detention facilities or other structural BMPs.
(j) All stormwater runoff from new development or redevelopment shall be pretreated for water quality prior to discharge to surface or groundwater. Rooftop runoff may go directly to an infiltration BMP or be evapotranspirated.
(k) All regulated activities within the municipality shall be designed, implemented, operated and maintained to meet the purposes of this chapter, through these two elements:
(1) Erosion and sediment control during earth disturbance activities (e.g., during construction); and
(2) Water quality protection measures after completion of earth disturbance activities (i.e., after construction), including operations and maintenance.
(l) The BMPs shall be designed, implemented, and maintained to meet state water quality requirements and any other more stringent requirements as determined by the municipality.
(m) Post-construction water quality protection shall be addressed as required by § 1043.17.
(o) All BMPs used to meet the requirements of this chapter shall conform to the state water quality requirements and any more stringent requirements as set forth by the municipality.
(p) Techniques described in Appendix C (Low Impact Development) of this chapter shall be considered because they reduce the costs of complying with the requirements of this chapter and the state water quality requirements.
(q) In selecting the appropriate BMPs or combinations thereof, the applicant shall consider the following:
(1) Total contributing drainage area;
(2) Permeability and infiltration rate of the site’s soils;
(3) Slope and depth to bedrock;
(4) Seasonal high water table;
(5) Proximity to building foundations and wellheads;
(6) Erodibility of soils;
(7) Land availability and configuration of the topography;
(8) Peak discharge and required volume control;
(9) Stream bank erosion;
(10) Efficiency of the BMPs to mitigate potential water quality problems;
(11) The volume of runoff that will be effectively treated;
(12) The nature of the pollutant being removed;
(13) Maintenance requirements;
(14) Creation/protection of aquatic and wildlife habitat;
(15) Recreational value; and
(16) Enhancement of aesthetic and property values.
(r) The design of all stormwater management facilities shall incorporate sound engineering principles and practices in a manner that does not aggravate existing stormwater problems. The municipality reserves the right to disapprove any design that would result in construction in or continuation of a stormwater problem area.
(s) The applicant may meet the stormwater management criteria through off-site stormwater management measures as long as the proposed measures are in the same subwatershed as shown in Appendix A.
(t) Stormwater hotspots.
(1) Stormwater runoff from hotspots shall be pretreated prior to surface or groundwater infiltration to prevent pollutant runoff. Industrial sites referenced in 40 C.F.R. part 125 are examples of hotspots.
(2) Below is a list of examples of hotspots:
A. Vehicle salvage yards and recycling facilities;
B. Vehicle fueling stations;
C. Vehicle service and maintenance facilities;
D. Vehicle and equipment cleaning facilities;
E. Fleet storage areas (bus, truck and the like);
F. Industrial sites based on Standard Industrial Classification Codes;
G. Marinas (service and maintenance areas);
H. Outdoor liquid container storage;
I. Outdoor loading/unloading facilities;
J. Public works storage areas;
K. Facilities that generate or store hazardous materials;
L. Commercial container nursery;
M. Contaminated sites/brownfields; and
N. Other land uses and activities as designated by an appropriate review authority.
(3) The following land uses and activities are not normally considered hotspots:
A. Residential streets and rural highways;
B. Residential development;
C. Institutional development;
D. Office developments;
E. Nonindustrial rooftops; and
F. Pervious areas, except golf courses and nurseries (which may need an integrated pest management (IPM) plan).
(4) While streets and highways (average daily traffic volume (ADT) greater than 30,000 are not considered stormwater hotspots, it is important to ensure that highway stormwater management facilities are designed to adequately protect receiving streams and/or groundwater.
(5) The Environmental Protection Agency’s (EPA) NPDES stormwater program requires some industrial sites to prepare and implement a stormwater pollution prevention plan.
(u) (1) The following standards for protection of downgradient properties from off-site conveyance must be accomplished.
(2) For any location where a new concentrated discharge of stormwater from any frequency rainfall event, up to and including the 100-year, 24-hour event, will flow onto a downgradient property, the following are required.
A. A drainage easement (or other legal agreement/approval) must be obtained for conveyance of discharges onto or through adjacent properties.
B. The conveyance must be designed to avoid erosion, flooding, or other damage to the properties through which it is being conveyed.
(Ord. 928, passed 6-18-2014)