(a) Introduction. This section provides performance standards that apply to all earth- disturbing activities subject to these regulations. An engineered plan must also be submitted pursuant to Section 943.04(e) if earth-disturbing activities will disturb soil on one or more acres of land on a single lot or tract, or on less than one acre that is part of a larger common plan of development or sale (e.g., a subdivision) if the larger common plan will ultimately disturb at least one acre. Some projects, whether or not required to submit engineered plans, must comply with the post-construction standards in Section 943.05 and enter into an Inspection and Maintenance Agreement where necessary to control stormwater after completion of construction.
(b) Applicability.
(1) The performance standards in this section apply to all developments that have any of the following characteristics:
A. The development will involve at least 3,000 square feet of earth- disturbing activities;
B. The development is part of a larger common plan that will involve at least 3,000 square feet of earth-disturbing activities, such as a subdivision or subdivided land;
C. The development will:
1. Create at least 2,000 square feet of impervious surface,
2. Add impervious surface to a development already possessing at least 2,000 square feet of impervious surface, or
3. Add impervious surface that in combination with existing impervious surface creates a total of at least 2,000 square feet of impervious surface;
D. The proposed development will significantly change the use (e.g., from residential to commercial) of a development previously subject to this section; or
E. The development will involve earth-disturbing activities within 100 feet of a stream, a wetland, or Special Flood Hazard Area (see the Richland County Floodplain Regulations for additional requirements).
For developments in progress on the effective date of these regulations in which at least the threshold amount of the activities identified in subsection (b)(1) hereof will occur after the effective date, the activities occurring after the effective date are subject to the newly promulgated requirements of Section 943.03. Other activities subject to the previous regulations shall continue to comply with the standards and other requirements of the previous regulations and any permits, plans, agreements, and other obligations established pursuant to the previous regulations. (E.g., if 5,000 square feet of a 20,000 square foot development are disturbed before the effective date, that 5,000 square feet would be subject to the previous regulations while the remainder would be subject to the new regulations.)
(2) Where a performance standard in this section is expressly limited to earth- disturbing activities of a specific acreage, that performance standard applies only to earth-disturbing activities of that size.
(c) Initiation of Work.
(1) At least 30 days prior to initiating earth-disturbing activities for which SWM/SC Engineered Plans are not required under Section 943.04, the Owners/Operators shall submit to the Stormwater Manager a permit application by completing an application form provided by the Stormwater Manager and submitting the information required by the checklist for applications contained in the Appendix to these regulations. The Stormwater Manager shall review and act on the approval or disapproval of these permit applications. No earth-disturbing activities or construction shall commence prior to the issuance of the permit.
(2) The Owners/Operators shall notify the Stormwater Manager at least 48 hours prior to commencement of earth-disturbing activities for all developments subject to these regulations. The Owners/Operators shall notify the Stormwater Manager within 24 hours after project completion.
(d) Protection of Adjacent Properties.
(1) Properties adjacent to the site of land disturbance, including public lands, streets, roads and waters, shall be protected from sediment deposition. This shall be accomplished by preserving a well-vegetated buffer strip around the lower perimeter of the land disturbance, by installing perimeter controls such as sediment barriers, filters, dikes or sediment basins, or by a combination of such measures.
(2) Prior to conducting Earth-Disturbing Activity that may affect Village, County or Township streets, roads or rights-of-way outside of the Village, the Owners/Operators shall consult with the Village Engineer or the affected Township official for selecting measures to protect public streets, roads and rights-of-way from adverse effects caused by sedimentation. The Owners/Operators shall contact the Village Engineer or affected Township official to arrange a time and place for the consultation.
(e) Vegetative Cover.
(1) A permanent vegetative cover shall be established on graded areas not otherwise permanently stabilized. Permanent vegetation shall not be considered established until a ground cover of at least 75% is achieved that is mature enough to control soil erosion satisfactorily and to survive severe weather conditions.
(2) Seed types, fertilizers, and mulches shall be selected and utilized that shall produce a healthy growth of vegetation during the time of year the seeding will take place. For assistance in selecting seed types, fertilizer, and mulches, the Owners/Operators are referred to Tables 6 or 7 of Appendix A of these regulations or the ODOT 659 Seeding Schedule. Recommendations for seed types, fertilizers, and mulches are also available from the Natural Resources Conservation Service (NRCS) or your local seed supplier.
(3) Oats, wheat or winter rye may be used for temporary vegetative cover.
(4) All seeded areas shall be appropriately mulched with straw cover or other suitable materials. The type and rate can be found in Table 6 of Appendix A or from the current edition of the Ohio Department of Natural Resources’ handbook entitled “Rainwater and Land Development: Ohio’s Standards for Stormwater Management Land Development and Urban Stream Protection.”
(f) Soil Stabilization.
(1) When required by the Stormwater Manager, silt fences and sediment basins shall be installed in accordance with manufacturer’s recommendations prior to any earth-disturbing activities.
(2) Temporary soil stabilization shall be applied within seven days after rough grading on non-vegetated areas that will remain idle (not be re-graded) for longer than 30 days, unless an extension is granted by the Stormwater Manager.
(3) Permanent vegetation shall be installed on any portion of the site on which final grade has been achieved within seven days after final grading. Soil stabilization measures shall be selected that are appropriate for the time of the year, site conditions, and estimated length of use.
(4) Soil stockpiles shall be protected with soil stabilization measures or sediment trapping measures to prevent soil from leaving the site.
(5) All areas within 50 feet of a stream, wetland, or body of water shall be stabilized immediately after achieving final grade.
(g) Stormwater Runoff Control and Treatment.
(1) Treatment of stormwater runoff requires the use of BMPs and/or the proper geo-textile product that may include grassed/vegetated areas or sedimentation basins to remove sediment and/or contaminants. Treatment must occur and remain on the development site to comply with subsection (d) hereof.
(2) Owners/Operators shall control waste such as discarded building materials, chemicals, litter, and sanitary waste to prevent them from reaching water resources. Any cleaning or washing of concrete trucks, well drilling equipment, and related equipment shall be conducted in a manner that shall prevent the wash water and pollutants from reaching water resources.
(3) Vegetated filter strips of a correct width and length may be utilized when sheet or overland flow is planned (i.e., when stormwater is not collected). Whenever a vegetated filter strip alone is ineffective in stopping sediment movement onto adjacent property, additional perimeter controls shall be provided.
(4) Roof drains shall be a reasonable distance from the property line to avoid flooding and excess discharge of water into road ditches or storm drains. Splash pads should be used whenever possible.
(h) Sediment Basins/Traps. When five or more contiguous acres are disturbed in one watershed, stormwater runoff from that development area shall pass through a sediment basin or other suitable sediment trapping facility. The sediment basins shall be designed with the equivalent of 67 Cubic Yard /Acre or greater storage capacity. The Stormwater Manager may require sediment basins or traps for smaller disturbed areas where deemed necessary. The sediment basin requirement may be eliminated if the Stormwater Manager finds that site conditions do not warrant its construction. Sediment basins or traps are temporary and shall be removed following final stabilization of the site.
(i) Installation of Sediment Controls. Sediment basins, traps, silt fences, sediment barriers and other measures to trap sediment on-site shall be constructed as a first step in grading and be made functional before upslope land disturbance or building construction takes place. Earthen structures such as dams, dikes, and diversions shall be seeded and/or mulched within seven days (or as weather conditions permit) after installation is complete.
(j) Storm Sewer Inlet Protection. All storm sewer conduit and catch basin inlets made operable during construction shall be protected so that sediment-laden water will not enter the conveyance system without first being filtered or otherwise treated to remove sediment. Treatment shall consist of either temporary or permanent measures or the use of geo-textile products and BMPs.
(k) Cut and Fill Slopes. Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion. Consideration should be given to the length and steepness of the slope, the soil type, upslope drainage area, groundwater conditions and other applicable factors. Slopes that are eroding excessively during the first 12 months after construction shall be provided with additional slope stabilizing measures until the problem is corrected. The following guidelines are provided to aid in developing an adequate design:
(1) Roughened soil surfaces are generally preferred to smooth surfaces on slopes.
(2) Concentrated stormwater should not be allowed to flow down cut or fill slopes unless contained within an adequate channel, flume, or slope drain structure.
(3) Wherever a slope face crosses a water seepage plane that endangers the stability of the slope, adequate drainage or other protection should be provided.
(4) On long or steep slopes or easily eroded soils, silt fencing may be required on the contours to minimize erosion and allow vegetation to be established.
(5) Protection is required to ensure final stabilization for a period of 12 months after construction.
(l) Stabilization of Waterways and Outlets. All on-site stormwater conveyance channels, except roadway ditches, shall be designed and constructed to withstand the expected velocity of flow from a 10 year frequency design storm (24-hour duration) without erosion. Adequate stabilization to prevent erosion shall also be provided at the outlets of all pipes and paved channels. Roadway ditches shall be designed according to the Village Subdivision Regulations and Public Improvement Standards.
(m) Working in or Crossing Watercourses.
(1) Construction vehicles shall be kept out of water resources to the extent possible. Where in-channel work is necessary, precautions shall be taken to stabilize the work area during construction to minimize erosion. The channel (including bed and banks) shall always be re-stabilized immediately after in-channel work is completed.
*** Note: Permits from other government agencies, including the U. S. Army Corps and/or Ohio EPA, may be necessary to perform in-stream channel projects. For further information on Ohio EPA or Army Corps permits, you may call Ohio EPA’s Division of Surface Water at (614) 644- 2001 or the Army Corps’ Huntington District at (304) 529-5210 or Buffalo District at (419) 898-3491.
(2) When construction vehicles regularly traverse a live (wet) watercourse during construction, a temporary vehicular stream crossing shall be constructed and used to protect the stream bed from disturbance.
(n) Maintenance of Erosion and Sediment Control Measures. All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of their intended functions. The Owners/Operators shall be responsible for such maintenance until the final inspection by the Stormwater Manager. For long- term maintenance, see Section 943.04(b)(5).
(o) Removal and Disposal of Temporary Measures. All temporary erosion and sediment control measures, including silt fences, shall be disposed of in accordance with directions from the Stormwater Manager within 30 days after final site stabilization is achieved. Trapped sediment and other disturbed soil resulting from the temporary measures shall be properly removed and stabilized.
(p) Incorporation of Some Standards by Reference. The standards and details for stormwater management, sediment control, and stream protection practices required by this section include the following:
(1) The standards and details published by the Ohio Department of Natural Resources in the current edition of “Rainwater and Land Development: Ohio’s Standards for Stormwater Management Land Development and Urban Stream Protection.”
(2) The standards and details that may be published by the Stormwater Manager.
(3) Natural Resources Conservation Service (NRCS) TR-55 & TR-20 Urban Hydrology for Small Watersheds.
(q) Stormwater Control/Design Methods.
(1) To provide adequate stormwater management for 5,000 square feet or larger construction projects, the following criteria shall be used to control the increased peak rates and volumes of runoff:
A. The peak discharge rate of runoff from the critical storm event shall be controlled. The drainage area and runoff volumes under post- development conditions shall not exceed the peak discharge rate of runoff occurring under pre-development conditions for a one-year frequency, 24-hour storm.
B. Storms of less frequent occurrence (longer return periods) than the critical storm up to and including the 100-year storm shall have peak runoff discharge rates no greater than the peak runoff rates from equivalent size storms under pre-development conditions. Calculations of the 1, 2, 5, 10, 25, 50, and 100-year storms shall be considered adequate in designing and developing to meet this standard.
(2) The critical storm for a specific development drainage area is determined as follows:
A. Use the Natural Resources Conservation Service (NRCS) TR-55, Urban Hydrology for Small Watersheds or TR 20 to determine the total volume (acre-feet) of runoff from a one year, 24-hour storm occurring on the development drainage area before and after development.
B. After the volumes have been determined using subsection (q)(2)A. hereof, use Table 1 to determine the percent increase in volume of runoff due to development and, using this percentage, select the 24- hour critical storm from the following table:
If the percentage of increase in volume of runoff is: | ||
Equal to or greater than: | Less than: | The critical storm will be: |
-- | 10 | 1 year |
10 | 20 | 2 years |
20 | 50 | 5 years |
50 | 100 | 10 years |
100 | 250 | 25 years |
250 | 500 | 50 years |
500 | --- | 100 years |
To calculate the critical storm:
(Post Developed 1 yr. Storm Q) - Pre-Developed 1 yr Storm Q)
X 100
Pre-Developed Storm Q) = % change for critical storm Table 1 | ||
(For example, if the percent increase between the pre-development and post-development runoff volume for a one - year storm is 35%, the critical storm is a 5-year storm. The peak discharge rate of runoff for all storms up to this frequency shall be controlled so as not to exceed the peak discharge rate from the one-year frequency storm under pre-development conditions in the development drainage area. The post-development runoff from all less frequent storms need only be controlled to meet the pre-development peak discharge rate for each of those same storms.)
(3) Methods for controlling increases in the rate, volume, and discharge of stormwater runoff shall include the following:
A. The use of grass-lined road ditches rather than paved street gutters where practical, and discharging roof water to vegetated areas or grass and/or rock-lined drainage channels.
B. Grading and construction of terraces or diversions to slow runoff by diffusion, or use of grade control structures and geo-textile products.
C. Induced infiltration of increased stormwater runoff into the soil where practical. For example, constructing special infiltration areas or the use of under drains where soils are suitable, retaining topsoil for all areas to be re-vegetated, or providing good infiltration areas with proper emergency overflow facilities.
D. Provisions for detention and/or retention of stormwater, with properly designed retention basins being preferred. Ponds and lakes may be used as stormwater basins that provide multiple use areas for stormwater detention, recreation, wildlife, fire protection, and aesthetics. Constructed wetlands, dry detention basins, or subsurface storage areas are other options.
(r) Additional Standards for Single Family Residential Lots. The following additional performance standards shall apply to earth-disturbing activities associated with single family homes, whether developed individually or as part of a larger common plan of development or sale (e.g., a subdivision):
(1) Pre-existing vegetation shall be retained on idle portions of the building lot as long as construction operations allow.
(2) Clearing shall be done so only active work areas are bare.
(3) Temporary seed (annual rye, oats) and/or mulch shall be applied to areas that are bare and are not being worked actively for a period of 30 days.
(4) Soil stockpiles shall be stabilized or protected with sediment trapping measures where needed to prevent off-site soil loss.
(5) Silt fences shall control sediment loss from building lots. Silt fences shall not be constructed in pre-existing natural drainage courses or areas of concentrated flow.
(6) Other sediment control measures such as inlet protection and sediment traps shall be used as needed to control runoff of sediment.
(7) All access drives shall have gravel or crushed rock applied to the driveway area and maintained during construction.
(8) Mud tracked into the street or sediment settled around inlets or in roadside gutters or ditches shall be removed at least daily or more frequently if needed to prevent accumulation.
(9) Sediment on streets shall be removed by shoveling and scraping and shall not be washed off paved surfaces or into storm drains.
(10) Silt fence shall be erected prior to any earth-disturbing activities to reduce sediment loss from building lots. Silt fence shall be erected in accordance with manufacturers’ instructions.
(11) The grading plan shall be maintained as close to the original ground topography as possible within platted subdivisions.
(12) All concrete washouts shall be done on-site in the locations indicated by the site drawing.
(Ord. 07-40. Passed 7-16-07.)