1199.02  DESIGN STANDARDS.
   In order to control sediment pollution of water resources, the Owner(s) or person(s) responsible for the any Development area shall should use conservation planning and low impact Development practices pursuant to Chapter 1203 : Low Impact Development, to maintain the level of conservation established in the following standards, where feasible, as determined by the Community Development Department:
   (a)   The standards and specifications contained in the State of Ohio's Rainwater and Land Development manual. As technology and understanding of habitat and land function develop, the Director may determine that additional Best Management Practices (BMPs)/Storm Water Control Measures (SCMs) are appropriate. These regulations do not preclude the use of innovation or experimental Storm Water management technologies.
   (b)   Clearing and Grubbing: 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/SCMs. After the perimeter controls are in place and functioning, the remaining phase(s) of clearing and grubbing may continue.
   (c)   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 as the first step of 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.
   (d)   Stabilization of Denuded Areas: Disturbed areas must be stabilized as specified in the tables below, or according to the most current Ohio EPA NPDES Storm Water Permit Rules, whichever is most restrictive:
 
Permanent Stabilization
Area requiring Permanent Stabilization
Time Frame
Any areas that will lie undisturbed 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.
Temporary Stabilization
Area Requiring Temporary Stabilization
Time Frame
Any disturbed areas within fifty (50) feet of a stream and not at final grade
Within two (2) days of the most recent disturbance if the area will remain idle for seven (7) days or more
Disturbed areas that will be undisturbed for more than 14 days but less than one (1) year and not within fifty (50) feet of a stream
Within seven (7) days of the most recent disturbance within the area
Residential subdivisions for disturbance which has occurred on building lots
Within 7 days of the most recent disturbance if housing unit construction on the lot is not scheduled to begin within 14 days of the disturbance.
In any case, temporary or permanent stabilization will be properly installed, pursuant to the most recent edition of the Rainwater and Land Development manual, before the second building permit is issued.
Nonresidential subdivisions and commercial developments
Within 7 days of the most recent disturbance if further construction activity will not occur within 21 days of the disturbance.
Where vegetative stabilization techniques may cause structural instability or are otherwise prohibited, alternative stabilization techniques must be employed.
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.
   (e)   Sediment Settling Ponds: Required for any one of the following conditions: concentrated storm water runoff (e.g. storm sewer or ditches), runoff from denuded areas ten (10) acres or more, and all areas flowing at rates that exceed the design capacity of sediment barriers and/or other sediment barriers and/or inlet protection, shall pass through a sediment settling facility.  The facility's storage capacity shall be no less than sixty-seven (67) cubic yards per acre of total drainage area.
      (1)   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 ideal drawdown time is from three (3) to four (4) days (72 to 96 hours) with a minimum 48 hour drain time for sediment basins serving a drainage area over 5 acres.
      (2)   The design of Settling Ponds shall have a minimum length of flow of 2:1.
      (3)   If feasible, sediment settling ponds shall be dewatered at the pond surface using a skimmer or equivalent device.  The settling pond volume consists of both a dewatering zone and a sediment storage zone
         A.   The volume of the dewatering zone shall be a minimum of 1800 cubic feet (ft3) per acre of drainage (67 yd3/acre) with a minimum 48-hour drain time for sediment basins serving a drainage area over 5 acres.
         B.   The volume of the sediment storage zone shall be calculated by either (1) the volume of sediment storage shall be 1000 ft3 per disturbed acre within the watershed of the boundary or (2) the volume of the sediment storage zone shall be the volume necessary to store sediment as calculated with RUSLE or a similar generally accepted erosion prediction model.
   (f)   Sediment Barriers, Silt Fence, Filter Sock, Diversions or another mechanisms deemed appropriate by the Community Development Department: Sheet flow runoff from denuded areas shall be intercepted to protect adjacent properties and water sources from sediment transported via sheet flow. The total runoff flow treated by a sediment barrier shall not exceed the design capacity for that sediment barrier.
      (1)   Silt fence shall be placed on a level contour downslope of the disturbed area. Placing silt fence in parallel does not extend the permissible drainage area to the silt fence.
Silt Fence Maximum Drainage Area Based on Slope
 
Maximum drainage area
(in acres) to 100 linear feet of silt fence
Range of slope for particular
drainage areas (in percent)
0.5
< 2%
0.25
>2% but< 20%
0.125
>20% but< 50%
 
   (g)   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 repeatedly during construction, an approved temporary crossing shall be constructed. Streams, including bed and banks, shall be restabilized immediately after in-channel work is completed, interrupted, or stopped.
      (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 US Army Corps Of Engineers and Ohio EPA, for such purposes as, but not limited to, constructing bridges, culverts, or erosion control structures.
   (h)   Construction Access Routes:
      (1)   Measures shall be taken to prevent soil transport onto public roads, or surfaces where runoff is not checked by sediment controls. Gravel construction entrance(s) shall be implemented as required by the Director and the Ohio EPA.
      (2)   Where soil is transported onto a public road surface, the roads shall be cleaned thoroughly at the end of each day, or more frequently, in order to ensure public safety. Soil shall be removed from paved surfaces by shoveling or sweeping. Street washing shall be allowed only after shoveling or sweeping has removed most of the sediment.
   (i)   Unstable Soils:  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.
   (j)   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.
   (k)   Stabilization Of Outfalls And Channels: Outfalls and constructed or modified channels shall be designed and constructed to withstand the expected velocity of flow from a post-development, minimum ten-year (or greater) frequency storm without eroding.
   (l)   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 Director, covers 80% or more of the soil surface with a uniform density, provides adequate cover, and is mature enough to satisfactorily control soil erosion and survive adverse weather conditions.
   (m)   Disposition of Temporary Practices: All temporary 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 Director. Trapped sediment shall be permanently stabilized to prevent further erosion.
   (n)   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)   Discharges from dewatering activities, including discharges from dewatering of trenches and excavations are prohibited unless managed by appropriate controls approved by the Development Engineer, which will not adversely affect resource waters or adjacent off-site properties.  There shall be no turbid discharges to waters of the state resulting from dewatering activities.
   (o)   Permanent Stabilization of Conveyance Channels:  Operator(s) shall undertake special measures to stabilize channels and outfalls and prevent erosive flows. Measures may include seeding, dormant seeding, mulching, erosion control matting, sodding, riprap, natural channel design with bioengineering techniques, or rack check dams.
   (p)   Inlet Protection:  Other erosion and sediment control practice shall minimize sediment laden water entering active storm drain systems, unless the storm drain system drains to a Sediment Settling Pond. All inlets receiving runoff from drainage area of one or more acres will require a Sediment Settling Pond.
      (Ord. 2017-17.  Passed 3-15-17.)