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[[MN Stormwater comment page]]
 
[[MN Stormwater comment page]]
  
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==Erosion Prevention And Sediment Control: INSPECTOR’S COMPLIANCE GUIDE (under Minnesota’s General Storm Water Permit for Construction Activity)==
  
==Feedback Requested – New Stormwater Permit for Construction==
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'''When doing inspections:'''
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#Document time and date of the inspection, weather conditions and on-site contact persons.
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#Report any potential violations to the general contractor and representative of the owner.
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#Document all potential problems in field notes and photographs.
  
Although the current construction permit is not scheduled to expire until August of 2018, the MPCA intends on re-issuing the permit as soon as fall of 2017.  The expiration date coincides with the expiration of the Municipal Separate Storm Sewer System (MS4) Permit and the MPCA is concerned about having multiple general permits expiring on the same schedule due to limited staff resources.  Additionally the MPCA will not be proposing major changes in the draft permit.
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===RECORDS===
  
Although no major permit changes will be proposed, several minor changes identified by external stakeholders and MPCA staff are needed.  The MPCA is seeking early input on some of these proposed changes in the permit.  This is not the official public comment period and the MPCA will not be providing formal responses to all of the input received.  The MPCA will use the information gathered from this early input process when writing the proposed requirements in the draft permit.  The MPCA expects to public notice the draft permit and receive formal public comments sometime in the late summer or fall of 2017.
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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
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inspector’s or contractor’s vehicle.
  
===Issue #1===
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Temporary Erosion and Sediment Control Plan, completed in accordance with the permit Appendix A must be available within 24 hours.
  
The permit requires that stormwater runoff from new impervious surfaces be treated prior to discharge and, in general, requires permittees to consider infiltration or other volume reduction practices first as a means to accomplish this.  However, there are numerous site conditions in which infiltration is undesirable, such as the presence of contaminated soils or groundwater. The permit language should define such conditions as clearly as possible.  This proposed language change for the prohibition would direct permittees to design a different and more desirable type of stormwater treatment system in these locations such as a wet sedimentation basin or a filtration system.
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Permanent Erosion and Sediment Control Plan, completed in accordance with the permit Appendix B must be available within 24 hours.
  
:'''Current CSW language (Part III.D.1.j.iv):'''
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Records of all inspections must be available within 24 hours, including:
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*date of all rainfall events
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*date and time of inspections,
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*finding of inspections,
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*corrective actions taken (including dates and times), and
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*documentation of all changes to the Temporary Erosion and Sediment Control Plan made during construction.
  
#Infiltration is prohibited when the infiltration system will be constructed in: Areas where high levels of contaminants in soil or groundwater will be mobilized by the infiltrating stormwater.
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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).
  
:'''Proposed CSW permit language:'''
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===Permit Coverage Card===
  
:Infiltration is prohibited in:
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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:
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*construction site entrance, visible from the nearest public roadway;
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*where no construction site entrance exists, at a location visible from the nearest public roadway;
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*at the field office (if applicable); or
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• for linear utility and noncontiguous municipal projects (i.e., city street improvements), at the office responsible for the project’s administration.
  
#Areas where infiltrated stormwater could enter contaminated groundwater with levels over Health Risk Levels (HRL's), Health Based Values (HBV's) or Maximum Contaminate Levels (MCL's) unless appropriate environmental assessment is performed to demonstrate that infiltration will not have a negative impact on groundwater.  
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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).
#Areas where infiltrated stormwater could come into contact with contaminated soils above Soil Leaching Values (SLV’s) unless an appropriate environmental assessment is performed to demonstrate that infiltration will not have a negative impact on groundwater.
 
  
This proposed change in language is not intended to change the agency’s policy on this subject but rather clarifies the language “high levels” as used in the current permit.  The MPCA does not expect soil or groundwater testing at every site but rather intends for permittees to continue to use the screening assessment tool in the stormwater manual to determine if contamination might be present. In addition, Permittees can look up past remediation sites using the “What’s in my Neighborhood” tool on the MPCA website to access information on those properties.
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===EROSION AND SEDIMENT CONTROL DURING CONSTRUCTION===
  
Screening Assement Tool:
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'''Erosion Control.''' Permittee must use horizontal slope grading, construction phasing, temporary diversions, and/or other practices that minimize erosion.
https://stormwater.pca.state.mn.us/index.php?title=Screening_assessment_for_contamination_at_potential_stormwater_infiltration_sites#Has_a_contaminated_site_been_remediated_to_acceptable_levels.3F
 
  
What’s in my neighborhood:
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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:
https://www.pca.state.mn.us/data/whats-my-neighborhood
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*steeper than 3:1, within 7 days.
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*less than 3:1, but steeper than 10:1, within 14 days.
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*flatter than 10:1, within 21 days.
  
===Issue # 2  Temporary stabilization of ditches===
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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).
  
The current permit requires stabilization of any ditch or swale within 200 feet of the point of discharge within 24 hours after connecting to a surface water or property edge.  This part of the requirement is prosed to remain the same. The current permit also specifically states that some less effective stabilization methods such as mulch cannot be used in ditches or swales for stabilization and permittee(s) must rely on more robust practices such as erosion control blankets.  The MPCA has heard from numerous stakeholders that Best Management Practices such as disc anchored mulch may be adequate under certain limited conditions such as areas with little or no slope and installing blanket in all locations is cost prohibitive and not necessary. 
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'''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
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completed within five calendar days. (Note: Normally this should be completed before connection)
  
:'''Current CSW language (Part IV.B.4):'''
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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.
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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).
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===PERIMETER CONTROLS.===
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'''All down gradient perimeter sediment-control bmps must be in place before any up gradient land-disturbing activity begins.'''
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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.
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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:
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*Basins must provide 1,800 cubic ft of storage per exposed acre drained.
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• Basin outlets must be designed to prevent short circuiting and the discharge of floating debris.
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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).
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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.
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===BMP INSPECTION===
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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.
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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.
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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).
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===SEDIMENT LEAVING THE SITE===
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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.
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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.
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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).
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===VIOLATION FOLLOW-UP===
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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.
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Inspectors should follow this procedure:
  
:Applying mulch, hydromulch, tackifier, polyacrylamide or similar erosion prevention practices is not acceptable stabilization in any part of a temporary or permanent drainage ditch or swale.
 
  
:'''Proposed CSW permit language:'''
 
  
:Applying mulch, hydromulch, tackifier, polyacrylamide or similar erosion prevention practices is not acceptable stabilization within the normal wetted perimeter of a temporary or permanent drainage ditch or swale section that has a continuous slope of greater than 2%.
 
  
This change allows permittees more flexibility for the type of stabilization chosen for a ditch bottom.  The permit still requires that all BMP's chosen “must be selected, installed, and maintained in an appropriate and functional manner that is in accordance with relevant manufacturer specifications and accepted engineering practices”.  Additionally, as with all BMP requirements in the permit, If the selected BMP is found to be inadequate at minimizing erosion from ditches or swales, another more effective BMP must be utilized. 
 
  
==Comments==
 
  
'''The MPCA is seeking input on these proposed changes. Please submit your comments and suggestions below.  Providing your name and contact information is appreciated but not necessary.'''
 
  
[mailto:constructionstormwater.pca@state.mn.us Construction Stormwater at the MPCA.]
 
  
  

Revision as of 20:43, 6 June 2017

Warning: This page is an edit and testing page use by the wiki authors. It is not a content page for the Manual. Information on this page may not be accurate and should not be used as guidance in managing stormwater.

MN Stormwater comment page

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:








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