Erosion and Sediment Control Methods
Construction projects that fall under the National Pollutant Discharge Elimination System (NPDES) Construction Permit criteria are required to have temporary erosion and sediment controls, and waste controls as required by NPDES/Storm Drain System (SDS) General Permit MN R100001 or as listed below, whichever are more stringent.
Silt Fence - Silt fence or other alternate perimeter controls (e.g., bio rolls) must be installed along the perimeter of the area to be cleared and graded before any grading that takes place. Silt fence must also be placed around all soil and erodible materials stockpile site. Silt fence must be properly installed by being trenched and buried at least six inches into the soil. All silt fences must be repaired, replaced, or supplemented when they become nonfunctional or the sediment reaches 1/3 of the height of the fence. These repairs must be made within 24 hours of discovery, or as soon as field conditions allow access.
Stockpile Protections - Erodible stockpiles must not be placed in surface waters, including stormwater conveyances such as curb and gutter systems, conduits, and ditches. All exposed soil areas will be stabilized immediately to limit soil erosion whenever any construction activity has permanently or temporarily ceased on any portion of the site and will not resume for a period exceeding 14 calendar days. Stabilization measures include hydro-seeding, mulching, plastic sheeting, or similar measures to protect the stockpile from rain and wind erosion.
Vehicle Entrances - Temporary rock construction entrances or other vehicle tracking methods approved by Department of Environmental Health and Safety (DEHS) or its designated campus stormwater point-of-contact must be installed and maintained wherever vehicles enter and exit a site. Construction entrance must be stabilized with 1½ inch to 3 inch clear aggregate or an approved equal. On sites with high traffic, Best Management Practices (BMPs) such as stone pads, concrete or steel wash racks, or equivalent systems may be required to minimize vehicle tracking of sediment. Wash or replace rock as needed to maintain effectiveness. Wash water should be directed to sediment traps and not allowed to leave the site.
Dust Control - Dust and concrete dust control of the construction site will be primarily in the form of water or as specified by the Engineer. Fugitive dust deposited on off-site streets and surfaces must be swept or removed within 24 hours of discovery, or upon request by DEHS or its designated campus stormwater point-of-contact.
Street Cleaning - Tracked sediment must be removed from all off-site paved surfaces by street sweeping at a frequency sufficient to minimize off-site impacts or upon request by DEHS or its designated stormwater point-of-contact.
Dewatering Treatment - Turbid or sediment-laden water that is being removed from construction site by pumping or trenching must be treated to remove suspended solids before discharge. If the water contains oil or grease, it must be pretreated by passing through an oil-water separator or suitable filtration device (e.g. cartridge filters, absorbent pads) prior to discharge into the receiving water. Water may not be discharged in a manner that causes erosion to receiving channels or flooding of the discharge site. Water discharged to special waters must comply with Appendix A of the NPDES/SDS General Permit MN R100001.
Concrete and other Washout Wastes - Washouts must be designed to properly handle solids, wash water, and rainfall to prevent overflow. The liquid and solids washout wastes must not contact the ground. Liquid and solids waste must be disposed of properly and in compliance with Minnesota Pollution Control Agency (MPCA) rules. Check all concrete washouts facilities daily to determine if they have been filled to 75 percent capacity, which is when materials need to be removed. Self-installed washouts must be inspected daily to ensure that plastic linings are intact and sidewalls have not been damaged by construction activities.
Storm Drain Protection - Inlet protection will be placed prior to or concurrent with any up-gradient disturbance. Storm drain inlets will remain in place until stabilization of the site. Sediment deposits must be removed from these devices when the sediment has accumulated to between 1/3 and 1/2 of the design depth of the device, or when the device is no longer functioning as designed.
Site Inspections - The Contractor is responsible for inspections and maintenance on the site. Inspections and maintenance must be documented and readily available for review. Inspections are required as follows:
- Once every 7 days during active construction.
- Within 24 hours after a rainfall event greater than one-half inch rain 24 hours.
- Once every 30 days on stabilized areas.
- Within 24 hours after runoff occurs or 24 hours prior to resuming construction on frozen ground, whichever comes first.
Hazardous Materials and Wastes – These materials (including oil, diesel fuel, gasoline, hydraulic fluids, paint solvents, petroleum-based products, wood preservatives, additives, curing compounds, and acids) must be properly stored in sealed containers to prevent spills, leaks or other discharge. Storage and disposal of hazardous waste or hazardous materials must be in compliance with Minn.R.ch.7045 including secondary containment as applicable.
Solid Waste – Must be stored, collected and disposed of properly in compliance with Minn.R.ch.7035.
Portable Toilets – Must be positioned so that they are secure and will not be tipped or knocked over. Sanitary waste must be disposed of properly in accordance with Minn.R.ch. 7041.