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Erosion Prevention And Sediment Control: INSPECTOR’S COMPLIANCE GUIDE (under Minnesota’s General Storm Water Permit for Construction Activity)

When doing inspections:

  1. Document time and date of the inspection, weather conditions and on-site contact persons.
  2. Report any potential violations to the general contractor and representative of the owner.
  3. Document all potential problems in field notes and photographs.

RECORDS

The project’s final plans and specifications, which include both temporary and permanent control plan requirements, must be available at the construction site in either a field office or an inspector’s or contractor’s vehicle.

Temporary Erosion and Sediment Control Plan, completed in accordance with the permit Appendix A must be available within 24 hours.

Permanent Erosion and Sediment Control Plan, completed in accordance with the permit Appendix B must be available within 24 hours.

Records of all inspections must be available within 24 hours, including:

  • date of all rainfall events
  • date and time of inspections,
  • finding of inspections,
  • corrective actions taken (including dates and times), and
  • documentation of all changes to the Temporary Erosion and Sediment Control Plan made during construction.

If the records requirements are not being complied with, it may be a violation of permit provisions (see permit provisions parts I.C.1, I.C.2.a, I.C.2.b, I.C.2.c).

Permit Coverage Card

A notice of stormwater permit coverage card must be placed in a visible location at the construction site throughout the duration of the project. The card can be placed at any of the following locations:

  • construction site entrance, visible from the nearest public roadway;
  • where no construction site entrance exists, at a location visible from the nearest public roadway;
  • at the field office (if applicable); or

• for linear utility and noncontiguous municipal projects (i.e., city street improvements), at the office responsible for the project’s administration.

If the records requirements are not being complied with, it is a violation of permit provisions (see permit provisions parts I.C.2.d, I.C.3).

EROSION AND SEDIMENT CONTROL DURING CONSTRUCTION

Erosion Control. Permittee must use horizontal slope grading, construction phasing, temporary diversions, and/or other practices that minimize erosion.

Exposed slopes within 100 lineal feet from a water of the state, or from a curb, gutter, storm sewer inlet, or temporary or permanent drainage ditch that is connected to a water of the state should have temporary protection or permanent cover within the following time frames:

  • steeper than 3:1, within 7 days.
  • less than 3:1, but steeper than 10:1, within 14 days.
  • flatter than 10:1, within 21 days.

If erosion control is not being complied with, it is a violation of permit provisions (see permit provisions parts I.D.1.a, I.D.1.b).

Ditch and Outlet Stabilization. The bottom of any temporary or permanent drainage ditch constructed to drain water from a construction site must be stabilized within 100 lineal feet from a water of the state. Stabilization must be initiated within 24 hours of connecting the drainage ditch to a water of the state, existing gutter, storm sewer inlet, drainage ditch or other stormwater-conveyance system that discharges to waters of the state. Stabilization must be completed within five calendar days. (Note: Normally this should be completed before connection)

Before to connecting any pipe to a water of the state or drainage ditch, the pipe’s outlet must be provided with temporary or permanent energy dissipation to prevent erosion.

If the ditch and outlet stabilization is not being complied with, it is a violation of permit provisions (see permit provisions parts I.D.1.c, I.D.1.d).

PERIMETER CONTROLS.

All down gradient perimeter sediment-control bmps must be in place before any up gradient land-disturbing activity begins.

The permittee must minimize vehicle tracking of sediment off-site wherever vehicles exit the construction site onto paved surfaces. In areas where curb and gutter exist, inlet protection must be in place, along with a plan to keep impervious surfaces free of sediment.

Where 10 or more contiguous acres of exposed soil contribute to a discernible point of discharge, temporary sedimentation basins meeting the following criteria must be provided prior to runoff leaving the site of entering waters of the state:

  • Basins must provide 1,800 cubic ft of storage per exposed acre drained.

• Basin outlets must be designed to prevent short circuiting and the discharge of floating debris.

If the perimeter controls are not being complied with, it is a violation of permit provisions (see permit provisions parts I.D.2.a, I.D.2.b, I.D.2.c.1, I.D.2.c.2).

If permanent ponds are required, they can often be used in place of temporary ponds, but construction sediment should be removed before final Notice of Termination has been submitted.

BMP INSPECTION

Inspect all erosion- and perimeter-sediment-control BMPs to ensure integrity and effectiveness. All nonfunctional perimeter-sediment-control BMPs should be repaired when the trapped sediment reaches one-third of the height, or replaced or supplemented with functional BMPs within 24 hours of discovery. All nonfunctional erosion-control BMPs should be repaired or replaced within 24 hours of discovery, or as soon as field conditions allow access.

Inspect all sedimentation basins to ensure their effectiveness. When the depth of the sediment collected in the basin reaches the heights of the riser, or the storage volume, the basin should be drained and the sediment removed within 72 hours of discovery, or as soon as field conditions allow access.

If inspection and maintenance is not being complied with, it is a violation of permit provisions (see permit provisions parts I.E.1.a, I.E.1.b).

SEDIMENT LEAVING THE SITE

Inspect all drainage ditches and other waters of the state for evidence of sediment leaving the site. Unless the project has received approval or certification for depositing fill into waters of the state, the permittee should remove all sediment in drainageways, catch basins or other waters of the state and restabilize the areas where sediment removal results in exposed soil. The removal and stabilization must take place within seven days of discovery unless precluded by legal, regulatory or physical access restraints. If precluded, removal and stabilization must take place within seven calendar days of obtaining access.

Inspect all construction site vehicle exit locations for evidence of sediment being tracked off-site. Sediment should be removed from paved surfaces which do not drain back into the construction site within 24 hours of discovery.

If sediment leaving the site is not being inspected and corrected, it is a violation of permit provisions (see permit provisions parts I.E.1.c, I.E.1.d).

VIOLATION FOLLOW-UP

Alleged violations must be brought to the attention of the on-site general contractor and representative of the owner (if that person is present) before leaving the site.

Inspectors should follow this procedure:

  1. Thoroughly and accurately document all potential violations through the use of fieldinspection notes, photographs and audiovisual equipment, if possible.
  2. Write up a detailed inspection report and transmit it to the responsible party as soon as possible after the inspection.
  3. Request all potential violations be corrected in accordance with the time frames specified in the permit.
  4. Report continued potential violations and inadequate response to inspections to the MPCA.

Violations not remediated in accordance with the time frames specified in the permit are subject to MPCA enforcement action, pursuant to Minn. Stat. §§ 115.071, 116.072, and 609.671, for violation of water-quality environmental laws.








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