(a) For all regulated activities, unless preparation of an SWM Site Plan is specifically exempted in Section 937.02:
(1) Preparation and implementation of an approved SWM Site Plan is required.
(2) No regulated activities shall commence until the Municipality issues written approval of an SWM Site Plan which demonstrates compliance with the requirements of this Ordinance.
(b) SWM Site Plans approved by the Municipality, in accordance with Section 938.06, shall be on site throughout the duration of the regulated activity.
(c) The Municipality may, after consultation with DEP, approve measures for meeting the state water quality requirements other than those in this Ordinance, provided that they meet the minimum requirements of, and do not conflict with, State law including, but not limited to, the Clean Streams Law. The Municipality shall maintain a record of consultations with DEP pursuant to this paragraph.
(d) For all regulated earth disturbance activities, erosion and sediment control BMPs shall be designed, implemented, operated, and maintained during the regulated earth disturbance activities, i.e., during construction, to meet the purposes and requirements of this Ordinance and to meet all requirements under Title 25 of the Pennsylvania Code and the Clean Streams Law. Various BMPs and their design standards are listed in the Erosion and Sediment Pollution Control Program Manual (E&S Manual) 2, No. 363-2134-008 (April 15, 2000), as amended and updated.
(f) Impervious Areas:
(1) The measurement of impervious areas shall include all of the impervious area in the total proposed development even if development is to take place in phases.
A. Less than 500 square feet of impervious surface equals a fee in lieu of the provision of stormwater management facilities (Fee in lieu to be determined by client).
B. Regulated activities between 500 square feet may use a small projects guide that does not require an applicant to hire an engineer nor subject to a technical review.
C. Regulated activities greater than 2,000 square feet are required to submit a stormwater management plan and will also require engineering and technical reviews.
(2) For development taking place in phases, the entire development plan must be used in determining conformance with this Ordinance.
(3) For projects that add impervious area to a parcel, the total impervious area on the parcel is subject to the requirements of this Ordinance; except that the volume controls in Section 937.03 and the peak rate controls of Section 937.04 do not need to be retrofitted to existing impervious areas that are not being altered by the proposed regulated activity
(g) Stormwater flows onto adjacent property shall not be created, increased, decreased, relocated, or otherwise altered without written notification of the adjacent property owner(s). Such stormwater flows shall be subject to the requirements of this Ordinance.
(h) All regulated activities shall include such measures as necessary to:
(1) Protect health, safety, and property.
(2) Meet the water quality goals of this Ordinance, as stated in Section 935.03. Purpose, by implementing measures to:
A. Minimize disturbance to floodplains, wetlands, wooded areas, and existing vegetation.
B. Maintain or extend riparian buffers.
C. Avoid erosive flow conditions in natural flow pathways.
D. Minimize thermal impacts to waters of this Commonwealth.
E. Disconnect impervious surfaces by directing runoff to pervious areas, wherever possible.
F. Minimize soil disturbance and compaction. Topsoil, if removed, shall be replaced to a minimum depth equal to its depth prior to removal or four (4) inches, whichever is greater. (Additional topsoil may be needed for vegetation other than sod.)
(3) To the maximum extent practicable, incorporate the techniques for Low Impact Development Practices described in the Pennsylvania Stormwater Best Management Practices Manual (BMP Manual). If methods other than green infrastructure and LID methods are proposed to achieve the volume and rate controls required under this Ordinance, the SWM Site Plan must include a detailed justification demonstrating that the use of LID and green infrastructure is not practicable.
(i) The design of all facilities in areas of carbonate geology or karst topography shall include an evaluation of measures to minimize adverse effects, including hydro-geologic studies if required by the Municipality.
(j) Infiltration BMPs shall be spread out, made as shallow as practicable, and located to maximize use of natural on-site infiltration features while still meeting the other requirements of this Ordinance. In addition, infiltration BMPs shall include pre-treatment BMPs where appropriate.
(k) All natural streams, channels, swales, drainage systems and/or areas of surface water concentration shall be maintained in their existing condition unless an alteration is approved by the Municipality. All encroachment activities shall comply with the requirements of PA DEP 25 PA Code Chapter 105 (Water Obstructions and Encroachments), Rules and Regulations of PA DEP. Any approvals or permits issued do not relieve compliance as referenced in Section 935.08, Compatibility with Other Permit and Ordinance Requirements.
(l) All storage facilities shall completely drain both the volume control and rate control capacities over a period of time not less than 24 hours and not more than 72 hours from the end of the design storm. However, any designed infiltration at such facilities is exempt from the minimum 24-hour standard, i.e., may infiltrate in a shorter period of time, so long as none of the stormwater flowing into the infiltration facility is discharged directly into the surface waters of the Commonwealth. (Inordinately rapid infiltration rates may indicate the presence of large fractures or other conditions for which an additional soil buffer may be required.)
(m) All stormwater management facilities (excluding individual residential underground infiltration facilities) are considered structures and must comply with building setback requirements. The outside toe of slope of the embankment in a fill condition or the top of embankment in a cut condition shall be considered as the point that must meet the setback requirements. Individual residential underground infiltration facilities shall be a minimum of ten (10) feet from the property line. Discharge of controlled flows can be no closer to an adjacent property than two (2) times the length of the required discharge rip-rap apron. This requirement applies to discharge aprons that do not outlet to a defined waterway or an existing storm sewer. Minimum distance is ten (10) feet.
(n) Normally dry, open top, storage facilities should completely drain both the volume control and rate control capacities over a period of time not less than 24 hours and not more than 72 hours from the end of the design storm.
(o) The design storm volumes and precipitation intensities to be used in the analysis of discharge or runoff shall be obtained from the Precipitation-Frequency Atlas of the United States, Atlas 14, Volume 2, Version 3.0, U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), National Weather Service, Hydrometeorological Design Studies Center, Silver Spring, Maryland. NOAA's Atlas 14 can be accessed at: http://hdsc.nws.noaa.gov/hdsc/pfds/.
(p) For all regulated activities, SWM BMPs shall be designed, implemented, operated, and maintained to meet the purposes and requirements of this Ordinance and to meet all requirements under Title 25 of the Pennsylvania Code, the Clean Streams Law, and the Storm Water Management Act.
(q) Various BMPs and their design standards are listed in the BMP Manual.
(r) All work shall be in accordance with the Municipality's Construction and Material Specifications.
(Ord. 32-2011. Passed 10-4-11; Ord. 44-2022. Passed 8-16-22.)