A Comprehensive Stormwater Pollution Prevention Plan (C-SWPPP) is a fundamental requirement for permit approval. Each C-SWPPP must include a Stormwater Management and Sediment Control Section. The C-SWPPP must be in compliance with S.C. Regulation 72-300 and the most current SCDHEC NPDES CGP. The C-SWPPP must be in compliance with the county’s Stormwater Design Manual. Additionally, the C-SWPPP shall include, as a minimum, the following:
(A) A vicinity map indicating a north arrow, scale, boundary lines of the site and other information necessary to locate the development site.
(B) Information concerning location and permitting for off-site material, waste, borrow or construction material storage or disposal areas to be used during construction activities.
(C) The existing and proposed topography of the development site except for individual lot grading plans in single-family subdivisions if the subdivisions or phases of the subdivision are not mass graded. In subdivisions that are not mass graded drainage flow patterns will be shown for each lot by arrow indicators showing the general direction of surface flow.
(D) Physical improvements on the site, including present development and proposed development.
(E) Drainage easements shall have the following characteristics:
(1) Provide adequate access to all portions of the drainage system and structures.
(2) Provide sufficient land area for maintenance equipment and personnel to adequately and efficiently maintain the drainage system and all storm water facilities.
(3) Restriction on easements shall include prohibiting all fences and structures which would interfere with access to the easement areas and/or the maintenance function of the drainage system.
(F) An anticipated starting and completion date of the various stages of land disturbing activities as specifically outlined in the CGP and the expected date the final stabilization will be completed.
(G) A determination that the development is in compliance with Chapter 151 - Flood Damage Prevention of this code.
(H) At the discretion of the Stormwater Administrator, for all portions of the drainage system which are expected to carry over 50 cubic feet per second (cfs) for the 100-year, 24-hour storm, the 100-year plus one foot flood elevation analysis shall be required if one of the following criteria apply:
(1) The estimated runoff would create a hazard for adjacent property or residents; or
(2) The flood limits would be of such magnitude that adjacent residents should be informed of these limits.
(I) For all portions of the drainage system which are expected to carry 150 cfs or more for the 100-year, 24-hour storm, the 100-year plus one foot flood elevation analysis shall be done and flood limits shall be shown on the drainage plans. Such data shall be submitted in digital form, as well as in print, in a format specified by the Stormwater Administrator.
(J) A tree saving and planting plan consistent with the requirements in Chapter 155 - Zoning Code of this code or meeting the buffer requirement of the Construction General Permit (whichever is more restrictive).
(K) Construction and design details for structural controls.
(L) The expected timing of flood peaks through the downstream drainage system shall be assessed when planning the use of detention facilities.
(M) All stormwater management facilities and all major portions of the conveyance system through the proposed development (i.e., channels, culverts) shall be analyzed, using the 100-year, 24-hour design storm, for design conditions and operating conditions which can reasonably be expected during the life of the facility. The results of the analysis shall be included in the hydrologic-hydraulic study.
(N) If the site development plan and/or design report indicates that there may be a drainage or flooding problem or potential of a problem at the exit to the proposed development or at any point downstream as determined by the Stormwater Administrator, the Stormwater Administrator may require as outlined in the Design Manual:
(1) Water surface profiles plotted for the conditions of pre-development and post-development for the 25-year, 24-hour and 100-year, 24-hour storm events;
(2) Elevations of all structures potentially impacted by the 25-year, 24-hour and 100-year, 24-hour flows.
(O) All plans submitted for approval shall comply with the applicable requirements of this chapter.
(P) All plans submitted for approval shall contain certification by the operator that the land disturbing activity will be accomplished pursuant to the approved plan and that responsible personnel will be assigned to the project.
(Q) The C-SWPPP shall contain certification by the applicant that all land clearing, construction, development and drainage will be done according to the C-SWPPP or any approved revisions. Any and all SWPPPs may be revoked at any time if the construction of stormwater management facilities or other elements of the plan is not in strict accordance with approved plans.
(R) All plans shall contain certification by the operator of the right of the Stormwater Administrator to conduct on-site inspections.
(S) The plan shall not be considered approved without the inclusion of an approval stamp with a signature and date on the plans by the York County Planning and Development Department. The stamp of approval on the plans is solely an acknowledgment of satisfactory compliance with the requirements of these regulations. The approval stamp does not constitute a representation or warranty to the applicant or any other person concerning the safety, appropriateness or effectiveness of any provision or omission from the C-SWPPP.
(T) Approved plans remain valid for five years, at the discretion of the applicant, from the date of an approval. Renewals of the plan approvals will be granted by the Stormwater Administrator upon written request by the operator accompanied with a revised contact list and submittal of the renewal fees.
(Ord. 2819, passed 6-17-19)