The following items shall be included in the SWM Site Plan:
A. Appropriate sections from the Township’s Subdivision and Land Development Ordinance, and other applicable local ordinances, shall be followed in preparing the SWM Site Plans. In instances where the Township lacks Subdivision and Land Development regulations, the content of the SWM Site Plans shall follow the county’s Subdivision and Land Development Ordinance.
B. The Township shall not approve any SWM Site Plan that is deficient in meeting the requirements of this Ordinance. At its sole discretion and in accordance with this Article, when a SWM Site Plan is found to be deficient, the Township may either disapprove the submission and require a resubmission, or in the case of minor deficiencies, the Township may accept submission with modifications.
C. Provisions for permanent access or maintenance easements for all physical SWM BMPs, such as ponds and infiltration structures, as necessary to implement the Operation and Maintenance (O&M) Plan discussed in paragraph E.10 below.
D. The following signature block for the Township:
“(Township official or designee), on this date (Signature date), has reviewed and hereby certifies that the SWM Site Plan meets all design standards and criteria of the Township Ordinance No. (number assigned to Ordinance).”
E. The SWM Site Plan shall provide the following information:
1. The overall stormwater management concept for the project.
2. A determination of site conditions in accordance with the BMP Manual4. A detailed site evaluation shall be completed for projects proposed in areas of carbonate geology or Karst topography, and other environmentally sensitive areas such as brownfields.
3. Stormwater runoff design computations and documentation as specified in this Ordinance, including the recommendations and general requirements in Section 301.
4. When infiltration methods such as seepage pits, beds, or trenches are proposed between any septic system and any facility used for stormwater management, an analysis shall be submitted to verify that stormwater infiltration shall not affect groundwater elevation at the septic drain field site.
5. Expected project time schedule.
6. A soil erosion and sediment control plan, where applicable, as prepared for and submitted to the approval authority.
7. The effect of the project (in terms of runoff volumes, water quality, and peak flows) on surrounding properties and aquatic features and on any existing stormwater conveyance system that may be affected by the project.
8. Plan and profile drawings of all SWM BMPs, including drainage structures, pipes, open channels, and swales.
9. SWM Site Plan shall show the locations of existing and proposed on-lot wastewater facilities and water supply wells.
10. The SWM Site Plan shall include an O&M Plan for all existing and proposed physical stormwater management facilities. This plan shall address long-term ownership and responsibilities for O&M as well as schedules and costs for O&M activities.
11. All Stormwater Management Plans shall note that stormwater management facilities are a permanent part of the development and shall not be removed, altered, or modified.
12. A justification must be included in the SWM Site Plan if BMPs other than green infrastructure methods and LID practices are proposed to achieve the volume, rate and water quality controls under this Ordinance.
13. Whenever a stormwater management facility will be located in an area underlain by limestone or dolomite (e.g., carbonate formations: refer Section 509.2.I of the Zoning Ordinance) a geological evaluation of the proposed location shall be conducted to determine susceptibility to sinkhole formations. The design of all facilities over limestone formations shall include measures to prevent ground water contamination and, where necessary, sinkhole formation. Soils used for the construction of basins shall have low erodibility factors (“K” factors). Installation of an impermeable liner shall be required in detention or retention basins constructed over limestone formations.
14. It shall be the developer’s responsibility to verify whether the site is underlain by limestone formations. The following note shall be attached to all stormwater management plans and signed and sealed by the developer’s qualified professional “I, ____________, certify that the proposed detention/retention basin (circle one) is/is not underlain by limestone or dolomite.”
(Ord. 186, passed 9-12-2017)