1. Date and title of plan 
2. Vicinity map at scale not less that 1”= 1 mile 
3. Streets and property uses adjacent to the site 
4. North arrow (all plan sheets) 
5. Scale no more than 1” = 50' (graphic and numeric) 
6. Title of the plan 
7. Boundary lines of the site, where work will be performed including approximate acreage of site 
8. Name and address of property owner, developer or petitioner; the individual responsible for satisfactory completion of work and Individual/Organization preparing plan with seal (include COA for firms). 
9. Tax map and parcel numbers. 
10. Time schedule and sequence of construction or phasing. 
11. Non-residential sites - the total area for each of the following must be shown on the site plan and included in the SWPPP Report:
    • Roof - existing square feet and proposed square feet
    • Asphalt - existing square feet and proposed square feet
    • Concrete, gravel, or other hard surface - existing square feet and proposed square feet
    • Water surface - existing square feet and proposed square feet
    • Total Site Area = ___________Acres

1. Existing topography, with contour intervals of not greater than 5 feet. 
2. Existing contours extending not less than 20 feet outside of site boundary lines. 
3. Proposed contours of all disturbed areas. 
4. Grading limits (area of disturbance in acres) clearly delineated: include proposed lots, staging areas, stockpile waste/borrow areas, off-site improvements such as roadway, water, sewer, drainage or wetlands mitigation. 
5. Soil information (types, hydrologic group, special characteristics). 
6. Proposed improvements on the site (including any future development planned) 
7. Proposed and/or existing building(s) location with finished floor elevation(s) 
8. Proposed minimum finished floor elevation or minimum opening for structures/lots, with relevance to the following: FEMA FIRM Flood Hazard Area, Community Floodplain (locally identified flood-prone areas outside of FIRM zone), Headwater condition or other hydraulically critical controlling features (based on 100-year storm). 
9. Proposed and/or existing road(s) location with finished elevations (design curve data; if proposed) 
10. Borrow, stockpile, topsoil and/or waste areas shown on grading plan 
11. 100-year FEMA/FIRM flood hazard area and floodway, including elevations. Show limits on plan. Add note of reference for FIRM panel mapping and whether the flood hazard area and floodway impacts site. 
12. Adjoining lakes, streams, drainage ways, and any impaired waterbodies (identify tributary, etc.). 
13. Identify concentrated areas of stormwater inflow and adequate drainage outlet(s) for site. 
14. Area(s) designated for post-construction stormwater mitigation. 
15. Existing and proposed permanent easements for City maintained drainage systems.
16. Existing and proposed permanent easements for privately maintained drainage systems. (labeled as “private”). 
17. Minimum size easement is 20 feet (for all public easements), centered on facility (additional width may be required based on facility size and depth). Private easements may be reduced to a width of 10 feet pending facility size and prior approval of the Infrastructure Planning Manager.

1. Location of temporary and permanent vegetative and structural stormwater sediment control measures (include sediment ponds, silt fence, and construction entrance/exit, concrete truck wash out area, etc.). 
2. Construction drawings and details for temporary and permanent measures. 
3. Design calculations for sediment basins/traps and other erosion/sediment control measures. 
4. Sedimentology is required for sites disturbing one acre or more. All BMPs must meet a removal efficiency of 80% suspended solids or 0.5 ml/l peak settleable solids concentration, whichever is less. 
5. Analysis method for all temporary erosion control BMPs must be SCS Type II 24-hour, 10-year storm. 
6. Two-year and 10-year flow rates (disturbed condition) cannot exceed the pre-developed rate of restriction at all property line points of discharge. 
7. Pre-development curve numbers (CN) must reflect an undisturbed condition. 
8. Use minimum CN of 88 for disturbed conditions, or justify with calculations. 
9. Time of Concentration (Tc) limitations: sheet flow maximum flow length is 300 feet for pre-development and 50 to100 feet for post-development; maximum shallow concentrated flow length is 100 to 300 feet. 
10. Sedimentology shall be based on eroded particle characteristics for a minimum 12-inch horizon depth. 
11. Sediment traps & basins, including skimmer type facilities, shall have a length equal two times the width. 
12. Storm drain inlet protection, pre and post, including temporary measures for pre-final grade (weep/slot drains) and final grade (final asphalt lift) 
13. Maintenance schedule, requirements and responsible person(s) for temporary measures 
14. Erosion Control Matting required on the back side of all detention/sediment basins (immediate and timely installation) 
15. Areas and acreage to be vegetatively stabilized 
16. Planned vegetation with details of plants, seed, mulch, fertilizer 
17. Specifications for permanent and temporary vegetation 
18. Soil preparation
    • Preparation schedule 
    • Seeding schedule 
    • Method
    • Seeding mixes and rates
    • Type of sod
    • Seedbed preparation
    • Time of fertilizer applications
    • Mulching and related data 
19. ECB (erosion control blanket) Class A slope stabilization
    • Maximum slope 2:1
    • Temporary life span of one to three yrs
20. TRM turf-reinforced mats):
    • Type 1 slope stabilization – maximum slope 2:1 
    • Type 2 slope stabilization – maximum slope 1.5:1 
    • Type 3 slope stabilization – maximum slope 1:1 
    • Type 4 slope stabilization – 1:1 or greater

Rainfall Intensity Values

Intensity Chart (Rational Method)

SCS Type 2 Rainfall Depth Duration Frequency Values

1. Include calculations for the 2-, 10-, 25-, and 100-year storms (SCS 6-hour and 24-hour Type II distributions). 
2. Mitigation performance shall be in accordance with most current City ordinances requirements. Post development peak flows are limited to pre-development rates at property line point of discharge or acceptable analysis point:
   • Post-development phase: 2-, 10-, 25-, and 100-year 6-hour and 10-year 24 hour.
   • Construction phase: 2- and 10-year 6-hour and 10-year 24-hour.
   • Additional construction phase performance requirements may be required on a site-specific basis, as determined by the City. 
3. Additional mitigation measures will be required when extraordinary known identifiable downstream limiting conditions exists (as required by the City and/or determined by the design engineer). 
4. Evaluation of downstream capacity must focus on known or identifiable restriction(s) and/or use the 10% rule (evaluation of point downstream where site area is equal to 10% of watershed). 
5. We recommend that a pre-development analysis be submitted for review and approval prior to civil design. 
6. Pre-development and post-development volumes, velocities, and inflow/outflow hydrographs. 
7. Pre-development and post-development peak flow rates at all existing and proposed points of detention basin discharge, and property line point(s) of discharge, as applicable. 
8. Design calculations for outlet structure anti-floatation blocks. 
9. Time of concentration (Tc) limitations
   • Sheet flow component maximum flow length must be 300 feet for pre- development and 50 to 100 feet for post-development
   • Maximum shallow concentrated flow length is 100 to 300 feet (calculations required). 
10. Basin minimum freeboard - one foot below top of dam (100-year, 24-hour stage). 
11. Basin minimum freeboard for regulatory storm – 6 inches below emergency spillway (100-year, 6-hour stage). 
12. Design calculations and construction details of stormwater detention facilities.
13. Emergency spillway required for all basins constructed with a dam or berm (50-year storm capacity). 
14. Minimum dam/berm width for basins is 5 feet. 
15. Emergency outlet or spillway discharges into an adequately defined outlet. 
16. Maintenance schedule, requirements and responsible person(s) for permanent measures (shown on plan and included in SWPPP Report. 
17. Permanent detention/water quality facilities, with a depth two feet or greater, must be fenced with a fence at least 4 feet tall

1. Design calculations and construction details for storm drainage system including culverts, ditches, swales, gutters, etc. (storm drain schedule should include pipe material, size, invert, slope, length, flow, capacity, velocity, & hw/d, inlet flow and capacity, runoff area, runoff coefficient) 
2. Design calculations, cross sections and method of stabilization of existing and proposed channels (include temporary linings) 
3. Design calculations and construction details of energy dissipation at critical points of hydraulic transition, such as culvert outlets, significant changes in grade, direction or flow velocity. (for rip-rap aprons, include stone sizes (diameter) and apron dimensions) 
4. The through drainage and private drainage system shall be sized to convey flows for the twenty-five (25) year storm. 
5. For drainage areas, 20 acres or less, the rational method applies and a frequency adjustment factor (Cf) of 1.1 shall be used. 
6. For drainage areas greater than 20 acres, the SCS 24 hour storm analysis is required. 
7. Roadway cross-drain culverts shall be sized in accordance with the following (Cf = frequency correction factor): 
   • Residential & Collector Roads:
     • 25-year Storm
     • Cf = 1.1 
   • Thoroughfare
     • 50-year Storm
     • Cf = 1.2 
   • Highway
     • 100-year Storm
     • Cf = 1.25
8. Evaluation of downstream impact is required for upsizing of existing cross-drain culverts. Contact CRH Infrastructure Division for additional requirements. 
9. All storm drainage pipes located within rights-of-way or City easements must be at least 18 inches in diameter. 
10. Headwater requirements for culverts are as follows:
    • (30) Hw/d = 1.5 – pipe cross-section area of 30 square feet, or less
    • (31) Hw/d = 1.2 – pipe cross-section area greater than 30 square feet (32)
    • Contact our Infrastructure Division for exceptions to the above requirements 
11. Storm drainage system profiles are required for all public and private through drainage systems. 
12. Underground utilities shown and labeled in plan and profile. 
13. Drainage flow patterns identified with flow arrows for proposed and/or existing drainage ways. 
14. Reinforced concrete pipe is required in street rights-of-way or permanent City easements. Alternative pipe materials may be used in other areas, pending prior approval by the City. 
15. Details for all drainage structures should be shown on the plans. Catch basins can be either frame, grate and hood or SC DOT Type 16, 17, & 18. 
16. Minimum cover for Class III RCP is two feet and for Class IV RCP is one foot. Pipe cover is measured from the top of pipe to the "subgrade" of the pavement section. 
17. No open ditches in front yard of proposed residences. Drainage pipe should extend a minimum of thirty (30) feet from the rear of the house. 
18. Side slopes for ditches shall be no greater than 2:1. Flatter side slopes are preferred. Calculations shall verify ditch capacity for flow and erodibility. 
19. Headwalls or flared end sections are required at inlets and outlets of all pipe systems.  Maximum pipe length between drainage structures is 500 feet. 
20. Maximum depth of publicly maintained drainage structures shall be 8 feet (where feasible)  The minimum elevation drop across the invert of catch basins, manholes, junction boxes, etc. shall be 0.1 feet. 
21. All junction boxes, manholes, SC DOT Type 9 catch basins need to have manhole access (no blind structures). 
22. Minimum pipe slope is 0.5 percent (0.5 feet per 100 feet). If topography or existing limitations prevent the use of 0.5% slope, verify a minimum pipe scarring velocity of 2.5 fps. 
23. Maximum pipe velocity at outfall is 10 fps. 
24. Structures and materials shall comply with the City Standard Specifications and Details.  Existing and proposed drainage patterns (include off-site areas that drain through project)  Size and predominant land use of drainage areas (acreage) 
25. Plan indicating delineated drainage area (include off-site drainage) 
26. Size and location of existing and proposed drainage system, including culverts, ditches, & swales. 
27. Composite drainage areas delineated for each component of the drainage system. 
28. Roadway spread calcs are required at all catch basins and critical points. The max spread is 6' from edge of pavement. Calcs shall be based on 10-yr frequency (rational method) flow, 5 min. Tc. 
29. Minimum 20-foot storm drainage easement is required for all systems traversing across lots or conveying through drainage. Easements shall be labeled as private. Public easements will be required, at the discretion of the City

1. Water Quality (WQ) mitigation is required for all sites (80% TSS removal) 
2. Traditional retention/detention ponds shall mitigate the following volume of runoff for the entire area draining to pond, as follows: (1/2" x Area) for wet ponds and (1" x Area) for dry basins. 
3. WC detention basin draw-down time shall be 24-hour minimum and 72-hour maximum. Note, draw-down time cannot be based on a routed 1/2" or 1" storm - separate calcs are required  Detention pond WQ outlet devices must be factored into the overall pond outlet rating table configuration 
4. Combination Detention Pond & Sand Filter/Enhanced Dry Swale (rate based WQ measure)
5. Prefabricated Devices: Allowed on a case by case basis. Field and lab test documentation must be provided for verification of performance. Contact the City for pre-approval of all prefabricated devices. 
6. Details and calcs for all WQ BMPs. 
7. Anti-clogging measures required for all WQ basin outlets - less than 12 inches in diameter. 
8. Measures to protect permanent WQ BMP(s) from construction phase silt contamination 
9. Infiltration Trench or Natural Infiltration Areas: Not Allowed (soil types found in this geographical region are not conducive to infiltration) 
10. Provisions for mosquito control required for all wet ponds. Acceptable measures are six to eight feet of depth for most fishery requirements, fountain for adequate water movement, maintenance plan for seasonal stocking of appropriate "mosquito" fish measures, etc. 
11. WQ BMPs must be located to mitigate runoff from their prescribed drainage area and not located “on-line” with the through drainage system.

The following notes are required by the South Carolina Department of Environmental Services (DES) and the City of Rock Hill on stormwater plans:

1. If necessary, slopes which exceed eight (8) feet should be stabilized with synthetic or vegetative mats, in addition to hydroseeding. It may be necessary to install temporary slope drains during construction. Temporary berms may be needed daily until the slope is brought to grade.
2. Stabilization measures shall be initiated as soon as practicable in portions of the site where construction activities have temporarily or permanently ceased, but in no case more than 14 days after work has ceased, except as stated below:
   • A. Where stabilization by the 14th day is precluded by snow cover or frozen ground conditions, stabilization measures must be initiated as soon as practicable.
   • B. Where construction activity on a portion of the site is temporarily ceased, and earth-disturbing activities will be resumed within 14 days, temporary stabilization measures do not have to be initiated on that portion of the site.
3. After construction activities begin, inspections must be conducted at a minimum of at least once every calendar week, with no time period between inspections exceeding 9 days, and must be conducted until final stabilization is reached on all areas of the construction site. Contractor shall assess all BMPs within 24 hours of the end of a storm event of 1.0 inch or greater, as well as during the first rain event after the initiation of construction activities and subsequent BMP installation. Inspection frequencies for portions of the construction site that have reached temporary or final stabilization may be reduced to at least once every month, as long as the stabilization is maintained and there is no additional disturbance in these areas. Inspections for BMPs, such as sediment basins, ponds and/or traps, which may receive flow from land development and/or construction on individual lots, may be required to resume, if areas that drain to them become disturbed during future construction. Any temporary BMP that also serves to mitigate for peak flows, or is to be converted to a permanent post-development stormwater mitigation facility, must also be subject to regular inspections, throughout the course of construction or development, until said facilities have been converted to a post-development configuration and a N.O.T. is filed. If site inspections or other information identify BMPs that are damaged, inappropriately or incorrectly installed, or not operating effectively, then maintenance must be performed as soon as practicable, or as reasonably possible and no less than 48 hours from the time of identification(preferably before the next storm event).
4. Provide silt fence and/or other control devices as may be required to control soil erosion during utility construction. All disturbed areas shall be cleaned, graded and stabilized with grass in immediately after the utility installation. Fill cover and temporary seeding at the end of each day are recommended. Contractor must implement and maintain “seasonal” seeding to assure proper stabilization and vegetation, throughout the course of construction. If water is encountered while trenching, the water should be filtered to remove any sediments before being pumped back into any stormwater systems, water courses and waters of the state (WoS) or waters of the United States (WoU.S.).
5. All erosion control devices shall be properly maintained during all phases of construction until thecompletion of all construction activities and all disturbed areas have been stabilized. Additionalcontrol devices may be required during construction in order to control erosion and/or offsite sedimentation. All temporary control devices shall be removed once construction is complete and the site is stabilized.
6. The contractor must take necessary action to minimize the tracking of mud onto paved roadway from construction areas and the generation of dust. The contractor shall daily remove mud/soil from pavement, as may be required.
7. Residential subdivisions require erosion control features for infrastructure as well as for individual lot construction. Individual property owners shall follow these plans during construction or obtain approval of an individual plan in accordance with SC Reg. 72-300 Seq. and SCR100000.
8. Temporary diversion berms and/or ditches will be provided as needed during construction to protect work areas from upslope runoff and/or divert sediment laden water to appropriate traps or stable outlets.
9. All WoS or WoU.S., including wetlands, are to be flagged or otherwise clearly marked in the field. A double row of silt fence is to be installed in all areas where a 50-foot buffer cannot be maintained between the disturbed area and all WoS and a 130-foot minimum buffer for WoU.S. One row of silt fence must be wire- backed. A 25-foot no disturbance zone shall be maintained between the last row of silt fence and all WoS and a minimum 50-foot no disturbance zone for WoU.S. Buffers and no disturbance zones shall be measured from top of creek bank.
10. Litter, construction debris, oils, fuels and building products with significant potential for impact(such as stockpiles of freshly treated lumber) and construction chemicals that could be exposed to storm water must be prevented from becoming a pollutant source in storm water discharges.
11. A copy of the SWPPP (including civil construction plans and supporting documents), inspections records, and rainfall data must be retained at the construction site or a nearby location easily accessible during normal business hours, from the date of commencement of construction activities to the date that final stabilization is reached.
12. Initiate stabilization measures on any exposed steep slope (3H:1V or greater) where land- disturbing activities have permanently or temporarily ceased, and will not resume for a period of 7 calendar days.
13. Minimize soil compaction and, unless infeasible, preserve and stockpile topsoil for reuse.
14. Inspection Reports must include the following:
    • The inspection date
    • Names, titles, and the qualifications of personnel making the inspection if not previously given in an inspection report, unless those qualifications change;
    • All discharge points;
    • Weather information and a description of any discharges occurring at the time of the inspection;
    • Total rainfall since last inspection;
    • Location(s) of discharges of sediment or other pollutants from the Site;
    • Location(s) of BMPs that need maintenance;
    • Location(s) of BMPs that failed to operate as designed or proved inadequate for a particular location;
    • Location(s) where additional BMPs are needed that did not exist at the time of inspection;
    • Corrective action required including any changes to the OS-SWPPP necessary and implementation dates;
    • Site Name, Operator Name and permit number; and
    • Verification that all BMPs and stormwater controls identified in the OS-SWPPP have been installed and are operating as designed.
    • Determine if the construction sequence is being followed;
    • Status of corrective actions undertaken following previous inspection to include date(s) each item was addressed;
    • List of items that have carried over from previous inspection reports that were not addressed.
15. If existing BMPs need to be modified or if additional BMPs are necessary to comply with the requirements of this permit and/or SC's Water Quality Standards, implementation must be completed before the next storm event whenever practicable. If implementation before the next storm event is impracticable, the situation must be documented in the SWPPP and alternative BMPs must be implemented as soon as reasonably possible.
16. A Pre-Construction Conference must be held for each construction site with an approved On- Site SWPPP prior to the implementation of construction activities. For non-linear projects that disturb10 acres or more this conference must be held on-site unless the Department has approved otherwise.
17. Minimize the discharge of pollutants from equipment and vehicle washing, wheel wash water, and other wash waters. Wash waters must be treated in a sediment basin or alternative control that provides equivalent or better treatment prior to discharge.
18. Minimize the discharge of pollutants from dewatering of trenches and excavated areas. These discharges are to be routed through appropriate BMPs (sediment basin, filter bag, etc.).
    s)BMP measures for concrete truck washout shall be in accordance with the following:
    • Concrete trucks shall not typically be washed out on site. If concrete truck washout is permitted on site, coordinate location and BMP's with site inspector.
    • Do not dispose of concrete truck washout waste by dumping into a sanitary sewer, storm drain or onto soil or pavement that carries storm water runoff.
    • Concrete truck washout shall be disposed of in accordance with the following:
      • Designated area that will later be backfilled (slurry pit)
      • Designated area where concrete wash can harden and be disposed of as solid waste.
      • Location that is not subject to water runoff, and more than 50 feet away from a storm drain, open ditch, or receiving water way.
      • Pump excess concrete in concrete pump bin back into concrete mixer truck
      • Concrete washout from concrete pumper bins can be washed into concrete pumper trucks and discharged into designated washout area or properly disposed of offsite.
19. The following discharges from sites are prohibited:
    • Wastewater from washout of concrete, unless managed by an appropriate control;
    • Wastewater from washout and cleanout of stucco, paint, form release oils, curing compounds and other construction materials;
    • Fuels, oils, or other pollutants used in vehicle and equipment operation and maintenance; and
    • Soaps or solvents used in vehicle and equipment washing.
20. All chemical spills, oil spills, or fish kills must be reported to S.C. Department of Environmental Services Land & Waste Management Emergency Response – call the 24-hour emergency response line at 1-888-481- 0125.
21. Temporary toilet facilities shall be provided for all construction workers and site visitors in accordance with 2006 International Plumbing Code General Regulations, Section 311 (or current revision). Portable facilities shall be placed on level ground and away from storm drainage systems (ditches, catch basins, etc.). Disposal and handling of sanitary waste must comply with S.C. Department of Environmental Services requirements.
22. Final grades for grassed and landscaped areas shall require a minimum 4” of clean top soil, free of debris and contaminants, and preferably of native origin.
23. Stormwater mitigation measures shall be implemented in accordance with City of Rock Hill Infrastructure requirements, for water quality and quantity, including temporary controls for the land disturbance phase and permanent measures for post-construction.
24. Note on the Grading & Drainage Plan: Stormwater mitigation measures will be certified by the design engineer.

1. Table of Contents 
2. A complete narrative with a description of the following:
   • Site Location
   • Overall Watershed (river or creek basin, proximity to impaired stream, etc.)
   • Project Scope
   • Terrain & Existing Conditions (topography relief, floodplain, soil types, etc.)
   • Drainage Patterns & Receiving Waterway (property line points of discharge and reception)
   • Downstream Conditions
   • Adjoining Land Conditions
   • Stormwater Mitigation Analysis (methods & applications used for detention, water quality, erosion control, drainage system, etc.)
   • Summary of Impact (pre vs post for all storms with % increase or decrease at critical points of interest)
   • Soil Types
   • Any other pertinent information. 
3. Supporting calculations for Erosion Control and Sedimentology Measures 
4. Supporting calculations for Stormwater Detention Facilities 
5. Supporting calculations for Post-Construction Water Quality 
6. Supporting calculations for Storm Drainage System (public & private) 
7. Supporting calculations for Vegetative Stabilization 
8. Maintenance Schedule & Requirements for Post-Construction BMPs 
9. Pre and Post-Development Drainage Maps 
10. Analysis Model Diagram (Flow Chart)  
11. Analysis Input Data (hydrology, outlet structure rating table, etc.) 
12. Construction Sequence 
13. Soils Map 
14. Location Map 
15. USGS Quad Map 
16. FEMA FIRMette Map 
17. 8-1/2x11 or 11x17 of Detention Basin Grading Plan 
18. 8-1/2x11 or 11x17 of Detention Basin Outlet Structure (with storm level elevations shown)  Waters of the State (Delineation, Permits, etc.) 
19. Engineer’s Seal & Signature 
20. Company Certificate of Authorization 
21. 8-1/2x11 or 11x17 map of all lots subject to Minimum First Floor Elevation (include elevation)
22. Non-residential sites - the total area for each of the following must be shown on the site plan and included in the SWPPP Report:
    • Roof - existing square feet and proposed square feet
    • Asphalt - existing square feet and proposed square feet
    • Concrete, gravel, or other hard surface - existing square feet and proposed square feet
    • Water surface - existing square feet and proposed square feet
    • Total Site Area = ___________Acres
23. Flood study if required
    • Flood Study Checklist (PDF)