The potential for sediment pollution of water resources shall be addressed both by minimizing erosion at the development site and by filtering development site runoff to remove suspended sediment. Technical standards and specifications for measures to be taken to meet the following criteria are found in the current version of the EPA NPDES General Permit For Constrnction Site Stormwater and Rainwater and Land Development: Ohio's Standards for Stormwater Management, Land Development and Urban Stream Protection.
(a) Minimization of Erosion During Development.
(1) Denudation and temporary stabilization.
A. Only the minimum necessary part of the total development area shall be denuded at any one time.
B. Temporary soil stabilization treatment shall be applied within seven (7) days following rough grading of denuded areas that will remain dormant (undisturbed) for longer than fourteen (14) days. All necessary steps shall be taken to condition the soil to promote proper vegetative growth. Disturbed areas within fifty (50) feet of a stream shall be stabilized within two (2) days.
C. Soil stockpiles shall be stabilized and protected with sediment trapping measures as necessary to prevent soil loss.
(2) Working in or crossing streams.
A. If a flowing stream must be crossed by construction vehicles regularly during construction, a temporary stream crossing shall be provided. The structure size shall be approved by the City Engineer.
B. Construction vehicles shall be kept out of streams to the extent possible. Where in-channel work is necessary, precautions shall be taken to stabilize the work area during construction to minimize erosion. Stream channels (including bed and banks) shall be restabilized immediately after in-channel work is completed.
(3) Construction access routes. Measures shall be taken to prevent soil transport by vehicles tracking onto surfaces where runoff is not checked by sediment controls, or onto public roads. If soil is transported onto a public road surface by vehicles or by runoff, the roads shall be cleaned thoroughly each day. Soil shall be removed from paved surfaces by shoveling or sweeping. Street washing shall be utilized only after soil has been removed by shoveling or sweeping.
(4) Temporary open trenches. Where a temporary open trench accumulates water, the City Engineer shall have the power to order the installation and use of dewatering devices and to prescribe the manner of their discharge, so that no safety hazard occurs and neither resources nor off-site property shall be adversely affected.
(5) Sloughing and dumping. No soil, rocks, debris, or any other material shall be dumped or placed into water resources or into such proximity that it may readily slough, slip, or erode into water resources, unless such dumping or placing has been authorized by the City Engineer and, when applicable, by the Army Corps of Engineers and/or the Federal Emergency Management Agency (FEMA). (Authorization would be considered for such purposes as, but not limited to, constructing bridges, culverts, erosion control structures, and other in-stream or channel-bank improvement works).
(b) Temporary Measures for Removal of Suspended Sediment from Runoff. Until all denuded areas have been permanently stabilized against slippage and erosion by vegetative or other measures, the following temporary sediment removal standards shall apply:
(1) Timing of sediment trapping practices. Sediment trapping practices shall be made functional before upslope land disturbance takes place and shall remain functional throughout earth-disturbing activity. Settling facilities, perimeter controls, and other practices intended to trap sediment shall be implemented before grading and grubbing. They shall continue to function until the upslope development area is re-stabilized.
(2) Sediment filters. Sheet flow runoff from denuded areas shall be passed through sediment filters such as a silt fence or be diverted to settling facilities, in order to protect adjacent properties and water resources.
(3) Settling facilities. Concentrated stormwater runoff denuded areas shall pass through a temporary sediment-settling facility that has a dewatering storage capacity of sixty-seven (67) cubic yards per acre of drainage area with a minimum 48-hour drain time and a sediment storage zone of one thousand cubic feet per disturbed acre. Sediment settling facilities shall be dewatered at the pond surface using a skimmer or equivalent device. If the size of the denuded area contributing runoff is five (5) acres or more within a single watershed, the settling facility shall be a sediment basin. If effective perimeter controls are used on the subject property or on adjacent property, and/or if filtration is accomplished, then the size of the settling facility may, with approval of the City Engineer, be modified from the minimum.
(4) Storm sewer inlet protection. All storm sewer inlets that accept runoff from the development area shall be protected so that sediment-laden water will not enter the storm sewer system without first being passed through a sediment filter or otherwise treated to remove sediment.
(c) Following Development.
(1) Establishing of permanent vegetation. A permanent vegetation cover shall be established and maintained on denuded areas that are not otherwise permanently stabilized. Permanent soil stabilization treatment shall be applied to denuded areas within seven (7) days after final grade is reached on any portion of the site. In the event of adverse weather conditions, a reasonable extension of this time period may be approved by the City Engineer. All necessary steps shall be taken to condition the soil to promote proper vegetative growth. Permanent vegetation shall be considered established only when a ground cover is achieved that is mature and extensive enough to control soil erosion and to survive severe weather conditions.
(2) Cessation of temporary practices and disposition of temporary facilities. All temporary erosion and sediment control practices shall cease and temporary facilities shall be disposed of within thirty (30) days after final site stabilization is achieved or after they are no longer needed, unless otherwise authorized by the City Engineer. Trapped sediment shall be removed or permanently stabilized to prevent further erosion.
(3) Maintenance. All temporary and permanent erosion and sediment control practices and facilities shall be maintained and repaired as needed to assure continued performance of their intended function.
(Ord. 280(22-23). Passed 6-15-23.)