In order to control sediment pollution of water resources, the owner or person responsible for the development area shall use conservation planning and practices to maintain the level of conservation established in the following standards.
(a) The plan shall include measures that control the flow of runoff from disturbed areas so as to prevent soil erosion from occurring.
(b) Structural Practices shall be used to control erosion and trap sediment from areas remaining disturbed for more than 14 days.
(c) Sediment Barriers: Sheet flow runoff from denuded areas shall be intercepted by Silt Fence or Diversions to protect adjacent properties and water resources from sediment. Where intended to provide sediment control, Silt Fence shall be placed on a level contour. The relationship between the maximum drainage areas to Silt Fence for a particular slope is shown in the table below (placing silt fence in a parallel series does not extend the size of the drainage area).
Table 1: Silt Fence Applicability
Maximum drainage area (in acres) to 100 linear feet of Silt Fence | Range of slope for a particular drainage area (in percent) |
0.5 | <2% |
0.25 | > 2% but > 20% |
0.125 | > 20% but < 50% |
This does not preclude the use of other sediment barriers designed to control sheet flow runoff. The total runoff flow treated by a sediment barrier shall not exceed the design capacity for that sediment barrier. Straw Bale Barriers are not acceptable.
(d) Storm Water Diversion Practices: Storm water diversion practices shall be used to keep runoff away from disturbed areas and steep slopes where practicable. Such practices, which include Swales, Dikes or Berms, Pipe Slope Drains and Diversions, may receive storm water runoff from areas up to ten (10) acres. Storm water diversion practices alone are not considered a sediment control practice unless those are used in conjunction with a sediment settling pond.
(e) All sediment control practices must be capable of ponding runoff in order to be considered functional.
(f) Clearing and grubbing will be done in two (2) or more phases. The first phase will include only those locations necessary to install the perimeter soil erosion, sediment and storm water control BMPs. After the perimeter controls are in place and functioning, the remaining phase(s) of clearing and grubbing may continue.
(g) Timing of Sediment Trapping Practices: Sediment control practices shall be functional throughout all phases of up slope earth disturbing activity. Settling facilities, perimeter controls and other practices intended to trap sediment shall be implemented prior to grading and within seven (7) days from the start of grubbing. They shall continue to function until the up slope development area is permanently restabilized. As construction progresses and the topography is altered, appropriate controls must be constructed or existing controls altered to address the changing drainage patterns.
(h) Stabilization of Denuded Areas: Disturbed areas must be stabilized as specified in the tables below, or according to the Ohio EPA NPDES Storm Water Permit Rules, whichever is most restrictive:
Table 2: Permanent Stabilization
Area requiring permanent stabilization | Time frame to apply erosion controls |
Any areas that will lie dormant for one (1) year or more | Within seven (7) days of the most recent disturbance |
Any areas within fifty (50) feet of a stream and at final grade | Within two (2) days of reaching final grade |
Any other areas at final grade | Within seven (7) days of reaching final grade within that area |
Table 3: Temporary Stabilization
Area requiring temporary stabilization | Time frame to apply erosion controls |
Any disturbed areas within 50 feet of a stream and not at final grade | Within two days of the most recent disturbance if the area will remain idle for more than 21 days |
For all construction activities, any disturbed areas that will be dormant for more than 14 days but less than one year, and not within 50 feet of a stream | Within seven days of the most recent disturbance within the area For residential subdivisions, disturbed areas must be stabilized at least seven days prior to transfer of NPDES permit coverage for the individual lot(s). Proof of permit coverage transfer from Ohio EPA must be submitted to the City Engineer. The City Engineer shall then inspect the lot to ensure that the Temporary Seeding has been done. |
Disturbed areas that will be idle over winter | Prior to the onset of winter weather |
Where vegetative stabilization techniques may cause structural instability or are otherwise unobtainable, alternative stabilization techniques must be employed.
(i) Sediment Settling Ponds: A sediment settling pond is required for any one of the following conditions:
(1) Concentrated storm water runoff (e.g., storm sewer or ditch);
(2) Runoff from drainage areas, which exceed the design capacity of silt fence or other sediment barriers;
(3) Runoff from drainage areas that exceed the design capacity of inlet protection; or
(4) Runoff from common drainage locations with 10 or more acres of disturbed land.
(5) Alternative controls can be used if the owner can show, in writing, that the Ohio EPA approved the use of alternatives that the owner demonstrated to be equivalent in effectiveness to a sediment settling pond.
A. Where storm sewer drainage areas include 10 or more acres disturbed at one time, a temporary (or permanent) sediment settling pond must be provided until final stabilization of the site. In single-family residential construction, final stabilization is after the houses are built and permanent landscaping is done.
1. It is recommended that for drainage locations of less than 10 acres, smaller sediment settling basins and/or sediment traps be used.
B. Each facility's storage capacity shall be no less than 1800 cubic feet of dewatering zone area per acre of total contributing drainage area and 1000 cubic feet per disturbed acre of sediment storage zone area. The storage volume will be measured from the bottom of the basin to the top of the primary (principal) spillway.
C. Permanent storm water management ponds that are designed to trap sediment during construction shall be designed to provide for a slow release of sediment-laden water. The draw down time must be at least 48 hours, or meet the criteria in the Ohio Rainwater and Land Development manual whichever is most stringent.
D. The design configuration between inlet(s) and the outlet of settling ponds must provide at least two units of length for each one unit of width (> 2:1 length to width ratio); a length to width ratio of 4:1 is recommended.
E. The depth of the dewatering zone of the sediment settling pond must be less than or equal to five (5) feet.
F. Sediment must be removed from the sediment settling ponds when the design capacity has been reduced by 40%.
G. Public safety, especially as it relates to children, must be considered in the design. Alternative sediment controls must be used where site limitations would preclude a safe design.
H. Temporary sediment settling ponds will not be constructed in any stream channel.
I. All newly constructed sediment settling ponds shall be dewatered at the pond surface using a skimmer or equivalent device.
(j) Storm Sewer Inlet Protection.
(1) All storm sewer inlets that accept water runoff from the development area shall be protected so that sediment-laden water will not enter the storm sewer, unless the storm drain system drains to a Sediment Settling Pond and is exempted in writing by the City Engineer. In areas where construction will be ongoing, such as subdivisions, the storm sewer protection shall be maintained until all up slope areas reach final stabilization, as determined by the City Engineer.
(2) All inlets receiving runoff from drainage areas of one or more acres will require a sediment settling pond.
(3) At the end of this period the site owner shall hydraulically clean the storm sewers to the satisfaction of the City Engineer. All sediments shall be removed from the system and shall not be flushed downstream.
(k) Storm Sewer and Other Drainage Outlets: All storm sewers, footer drains, roof gutter drains and all other drains will be outletted at the bottom of the slope. The slope below the outlet will be able to control the water being drained through the storm sewer or other drains without causing erosion of the stream or channel banks or channel bottom or other areas that the water is outletted on.
(l) Working Near, or Crossing Streams and Wetlands:
(1) Construction vehicles shall avoid water resources, wetlands, riparian areas, and their setbacks. If construction vehicles must cross these areas during construction, an approved temporary crossing shall be constructed. Streams, including intermittent streams with a defined bed and banks, shall be restabilized immediately after in-channel work is completed, interrupted, or stopped. Erodible materials will not be used in making stream crossings.
(2) No soil, rock, debris, or any other material shall be dumped or placed into a water resource or into such proximity that it may slough, slip, or erode into a water resource unless such dumping or placing is authorized by the approving authority and, when applicable, the U.S. Army Corps of Engineers and Ohio EPA, for such purposes as, but not limited to, constructing bridges, culverts, and erosion or sediment control structures.
(3) If construction activities disturb areas adjacent to streams, structural practices shall be designed and implemented on site to protect the adjacent streams from the impacts of sediment runoff.
(4) No temporary or permanent sediment controls will be constructed in a stream channel.
(5) Streams and wetland setbacks required by the City will be implemented. As a minimum a setback of 25 feet, as measured from the ordinary high water mark of the surface water, will be maintained in its natural state as a permanent buffer.
(m) Construction Entrance:
(1) Measures shall be taken to prevent soil transport onto public roads, or surfaces where runoff is not checked by sediment controls.
(2) Stone with geotextile construction entrance(s) shall be implemented as required by the City Engineer and the Ohio EPA. These will be planned and installed according to the requirements in the most recent edition of the Ohio Rainwater and Land Development manual.
(3) Where soil is transported onto a public road surface, the roads shall be cleaned thoroughly via street sweeping at the end of each day, or more frequently, in order to ensure public safety. Street washing shall be allowed only after shoveling or sweeping has removed most of the sediment and approved storm sewer inlet protection is properly installed unless end of sewer sediment ponds exist and are properly functioning.
(4) Erodible material ramps in streets will not be used to enable equipment to cross curbs. Non-erosive materials (e.g. wood and stone) can be used.
(n) Unstable Soils:
(1) Unstable soils will be as determined by the local county Soil Survey or by a detailed soils report.
(2) The City Engineer may require detailed soil reports when deemed necessary.
(3) Unstable soils prone to slipping or land sliding shall not be graded, excavated, filled or have loads imposed upon them unless the work is performed in accordance with a qualified professional engineer's recommendations to correct, eliminate, or adequately address the problems.
(o) Cut and Fill Slopes: Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion and slippage. Consideration shall be given to the length and steepness of the slope, soil type, up slope drainage area, groundwater conditions and slope stabilization. The minimum final unreinforced soil slopes will have a horizontal to vertical ratio of 2:1 (the horizontal will be two (2) times the vertical).
(p) Stabilization of Outfalls and Channels: Outfalls and constructed or modified channels shall be designed and constructed to withstand the expected velocity of flow from the planned post-development frequency storm without eroding. The planned post-construction velocity and flow shall include the entire contributing watershed. Velocity dissipation devices shall be placed at discharge locations and along the length of any outfall channel to provide nonerosive velocity from the structure to a water course so that the natural physical and biological characteristics and functions are maintained and protected.
(q) Establishment of Permanent Vegetation: A permanent vegetative cover shall be established on denuded areas not otherwise permanently stabilized. Permanent vegetation shall not be considered established until ground cover is achieved which, in the opinion of the City Engineer, has 70% vegetative density over the entire disturbed area and provides adequate cover, and is mature enough to satisfactorily control soil erosion and survive adverse weather conditions.
(r) Disposition of Temporary Practices: All temporary soil erosion and sediment control practices shall be disposed of immediately after final site stabilization is achieved or after the temporary practices are no longer needed, unless otherwise required by the City Engineer. Trapped sediment shall be permanently stabilized to prevent further erosion. The Construction Maintenance Guarantee shall not be released by the City until all temporary soil erosion and sediment control practices that are no longer needed have been removed, properly disposed of and any trapped sediment has been stabilized.
(s) Underground Utility Construction: The construction of underground utility lines, pipes, etc. shall be subject to the following criteria:
(1) Trenches shall remain open for no more than five days.
(2) There shall be no turbid discharges to surface waters resulting from dewatering activities. If trench or ground water contains sediment, it must pass through a sediment settling pond or other equally effective sediment control device, prior to being discharged from the construction site or to waters of the State.
(3) When discharging clean ground water care must be taken to ensure that it does not become pollutant laden by crossing over disturbed soils or other pollutant sources.
(t) Inspections:
(1) If inspections or other information indicates a control has been used inappropriately or incorrectly or it has failed, it must be replaced or modified for the site conditions.
(2) The owner of the development area shall have the site inspected for soil erosion, sediment control and other environmental concerns every seven (7) calendar days, and within twenty-four (24) hours of a 0.5 inch or greater rainfall event until the City Engineer certifies the site as being stable. The City Engineer certification does not relieve the permittee from meeting the Ohio EPA NPDES inspection requirements.
(3) The inspection frequency may be reduced to at least once every month if the entire site is temporarily stabilized or runoff is unlikely due to weather conditions (e.g., the site is covered with snow, ice, or the ground is frozen.) A waiver of inspection requirements is available until one month before thawing conditions are expected to result in a discharge if all of the following conditions are met: the project is located in an area where frozen conditions are anticipated to continue for extended periods of time (i.e., more than one month); land disturbance activities have been suspended; and the beginning and ending dates of the waiver period are documented. Once a definable area has been fully stabilized, you may mark this on your plans and no further inspection requirements apply to that portion of the site.
(4) Following each inspection, a checklist must be completed and signed by the qualified inspection personnel representative. At a minimum, the inspection report must include: i) the inspection date; ii) names, titles, and qualifications of personnel making the inspection; iii) weather information for the period since the last inspection including the timing, duration, and depth of any storms; iv) weather information and a description of any discharge occurring at the time of the inspection; v) location(s) of discharges of sediment or other pollutants from the site; vi) location(s) of BMPs that need to be maintained; vii) location(s) of BMPs that failed to operate as designed or proved inadequate for a particular location; viii) location(s) where additional BMPs are needed that did not exist at the time of the inspection; and, ix) corrective action required including any necessary changes to the Storm Water Pollution Prevention Plan and implementation dates.
(5) The inspection log will include the date and actions taken to correct problems noted in past inspection logs.
(6) If the construction site is subject to Ohio EPA's National Pollutant Discharge Elimination System (NPDES) permit for construction activity, a copy of all of the required inspection sheets will be submitted to the City Engineer within three (3) working days of the date that the inspection was conducted.
(7) Disturbed areas and areas used for storage of materials that ate exposed to precipitation shall be inspected for evidence of, or the potential for, pollutants entering the drainage system.
(8) Erosion and sediment controls identified in the Storm Water Pollution Prevention Plan shall be observed to ensure that they are operating correctly.
(9) Discharge locations shall be inspected to ascertain whether erosion and sediment control measures are effective in preventing significant impacts to the receiving waters.
(10) Locations where vehicles enter or exit the site shall be inspected for evidence of off-site vehicle tracking.
(11) Sensitive means including riparian and wetland setbacks shall be observed to ensure that they remain well marked and undisturbed.
(12) If the inspection reveals that a control practice is in need of repair or maintenance, with the exception of sediment settling ponds, it must be repaired or maintained within three (3) days of the inspection. Sediment settling ponds must be repaired or maintained within ten (10) days of the inspection.
(13) If any inspection reveals that a control practice fails to perform its intended function and that another, more appropriate control practice is required, the Storm Water Pollution Prevention Plan must be amended and the new control practice must be installed within 10 days of the inspection.
(14) If the inspection reveals that a control practice has not been implemented in the time required by this chapter it must be installed within ten (10) days from the date of inspection.
(15) If the inspection reveals that a planned control practice is not needed, the record must contain a statement of explanation as to why the control practice is not needed.
(u) Control of Materials and Debris: Site management practices shall be implemented to prevent toxic materials, hazardous materials, or other debris from entering the City's and State's water resources or wetlands. These practices shall include, but are not limited to, the following:
(1) A covered dumpster shall be made available for the proper disposal of construction site waste materials, garbage, plaster, drywall, grout, gypsum and etc. A second covered dumpster will be provided for the proper disposal of toxic and hazardous wastes.
(2) The washing of excess concrete material into a street, catch basin, or other public facility or natural resource shall not occur. A designated area for concrete washouts shall be made available and used for all concrete washouts.
(3) All fuel tanks and drums shall be stored in a marked storage area. A dike shall be constructed around this storage area with a minimum capacity equal to 110% of the volume of the largest container in the storage area. All additional requirements of the local fire authority must be followed. If the fuel tanks have a self-contained "dike," the plug will be kept in the "dike" tank at all times.
(4) Any toxic or hazardous wastes and/or contaminated soils must be disposed of according to all applicable environmental laws and statutes. Local health districts and Ohio EPA can provide guidance on these issues.
(5) On a site with a prior industrial land use or a site that is contaminated with gasoline, fuel oil, hydrocarbon based chemicals or other Ohio EPA regulated contaminates, the storm water is considered wastewater. A permit from Ohio EPA is required to address these sites.
(6) Proper permits shall be obtained for development projects on solid waste landfill sites.
(7) Paint, paint washing liquids, excess paints and other paint wastes are considered solid wastes and shall be disposed of in accordance with applicable state regulations. Appropriate handling of these wastes shall occur at the site so as to prevent the discharge of these wastes into surface or ground waters.
A. Water based paint washing liquids and small quantities of excess water based paints may be disposed of by flushing down a connected sanitary sewer but may not be disposed of in an on-lot disposal system.
B. All other paints, paint thinners, and paint cleaning materials will be disposed of in the site's hazardous waste disposal dumpster.
(8) Restroom facilities will be provided for site workers at all times that workers are present on the site and during all phases of the construction.
(9) All required permits from appropriate federal, state, or local agencies are required to develop land with a previous industrial or commercial use or another use that may have led to soil contamination by a regulated pollutant.
(v) Storm Water Basins:
(1) Pool Geometry: The minimum length-to-width ratio for the pond is 3:1 (the length will be three (3) times the width).
(2) Riser in Embankment: The riser shall be located within the embankment for purposes of maintenance access. Access to the riser will be by manholes.
(3) Water Drains: Each retention basin shall have a drainpipe that can completely drain the pond. The drain shall have an elbow within the pond to prevent sediment deposition from plugging the drain.
(4) Adjustable Gate Valves: Both the storm water management and water quality basin drains shall have adjustable gate valves. Valves shall be located inside the riser at a point where they will remain dry and can be operated in a safe and convenient manner. During the annual inspections the valves shall be fully opened and closed at least once, and the certifying official shall attest to this on the inspection form. To prevent vandalism, the handwheel shall be chained to a ringbolt or manhole step.
(5) Principal Spillway: Each principal spillway shall be designed in accordance with the NRCS standards and specifications for the office serving the county. Each principal spillway shall have the capacity to pass the 100-year design storm flow. The inlet or riser size for the pipe drops shall be designed so that the flow through the structure goes from weir flow control to pipe flow control without going into orifice control in the riser. The crest elevation of the primary spillway shall be no less than one foot below the emergency spillway crest. Premium joint pipe is required and a removable trash rack shall be installed at each location. Anti-seep collars shall be provided for all pipe conduits through an embankment.
(6) Emergency Spillway: An emergency spillway shall be provided on each storm water management basin. Emergency spillways shall convey flood flows safely past the embankment, and shall be designed in accordance with NRCS standards and specifications for the office serving the local county. Emergency spillways shall have a 100-year design storm capacity unless exempted in writing by the City Engineer.
(7) Embankments: Each dam embankment shall be designed in accordance with the NRCS standards and specifications for the office serving the county that the project is located in. Anti-seep collars shall be provided for all pipe conduits through an embankment.
(8) Safety Features:
A. The primary spillway opening shall not permit access to the public and other non-maintenance personnel.
B. The perimeter of all water pool areas that are deeper than three (3) feet shall be surrounded by benches that meet the following:
1. A safety bench, with a maximum slope of 3%, which extends outward, on dry land, from the shoreline. This bench will be a minimum of 25 feet wide to provide for the safety of individuals and maintenance vehicles that are adjacent to the water pool. The safety bench may be landscaped, without the use of structures, to prevent access to the water pool.
2. Side slopes between the safety bench and the aquatic bench shall not be steeper than 3:1 (3 feet horizontal for every 1 foot vertical).
3. An aquatic bench that extends inward from the shoreline far enough to ensure public safety and has a maximum depth of 15 inches below the normal water surface elevations. The aquatic bench may be landscaped to prevent access to the deeper water pool.
4. Side slopes beyond the aquatic bench and below the pe1manent water level shall not be steeper than 2:1 (2 feet horizontal for every 1 foot vertical).
5. The contours of the pond will be designed and managed to eliminate drop-offs and other hazards.
6. Side slopes getting to the pond shall not exceed 3:1 and shall te1minate on a safety bench.
7. Soil erosion and sediment control practices used to satisfy these standards shall meet the standards and specifications in the current edition of the Ohio Rainwater and Land Development manual, NRCS Field Office Technical Guide for the local county or the Ohio EPA, whichever is most stringent.
(w) These standards are general guidelines and shall not limit the right of the City Engineer to impose at any time additional, more stringent requirements, nor shall the standards limit the right of the City Engineer to waive, in writing, individual requirements.
(x) Soil limitations shall be determined by using the current edition of the county soil survey written by the NRCS, USDA.
(y) Methods for controlling increases in storm water runoff peaks and volumes may include, but are not limited to:
(1) Retarding flow velocities by increasing friction; for example, grassed road ditches rather than paved street gutters where practical, discharging roof water to vegetated areas, or grass and rock-lined drainage channels.
(2) Grading and use of grade control structures to provide a level of control in flow paths and stream gradients.
(3) Induced infiltration of increased storm water runoff into soil, where practical; for example, constructing special infiltration areas where soils are suitable, retaining topsoil for all areas to be vegetated, or providing good infiltration areas with proper emergency overflow facilities.
(4) Provisions for detention and retention, for example, permanent retention ponds and lakes, dry detention basins, and subsurface detention tanks.
(Ord. 241-13. Passed 12-16-13.)