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The municipal separate storm sewer system [https://stormwater.pca.state.mn.us/index.php?title=MS4_General_Permit (MS4) General Permit] requires inspections of certain municipally owned/operated facilities, areas, or stormwater best management practices (BMPs) ([https://stormwater.pca.state.mn.us/index.php?title=MS4_PART_III.STORMWATER_POLLUTION_PREVENTION_PROGRAM_(SWPPP) MS4 General Permit Part III.D.6.e]). This includes:
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[[File:100 0120.JPG|200 px|thumb|right|alt=image showing staff collecting data from surface water|<font size=2>Staff collecting water data</font size>]]
*Annual inspections of structural stormwater BMPs to determine structural integrity, function, and maintenance needs.
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==Municipal operation inspections==
*At least one inspection every permit term of stormwater ponds and outfalls to determine structural integrity, function, and maintenance needs.  
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Municipal operation inspections help reduce the impacts to stormwater from municipally owned or operated facilities, areas, or stormwater best management practices (BMPs). Staff conducting these inspections can stop pollution before it reaches stormwater, or minimize the impacts if your BMPs have failed or need maintenance.
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The municipal separate storm sewer system [https://stormwater.pca.state.mn.us/index.php?title=Stormwater_Program_for_Municipal_Separate_Storm_Sewer_Systems_(MS4) (MS4) General Permit] requires inspections of the following: (MS4 General Permit Part III.D.6.e)
 +
*Annual inspections of [[#BMP inspection checklists|structural stormwater BMPs]] to determine structural integrity, function, and maintenance needs.
 +
*At least one inspection every permit term of [[#Pond inspection checklists|stormwater ponds]] and [[#Outfall inspection checklists|outfalls]] to determine structural integrity, function, and maintenance needs.  
 
*Quarterly inspections of stockpiles, and storage and material handling areas identified in the [https://stormwater.pca.state.mn.us/index.php?title=Facility_Inventory Facility Inventory] to determine function and maintenance needs.
 
*Quarterly inspections of stockpiles, and storage and material handling areas identified in the [https://stormwater.pca.state.mn.us/index.php?title=Facility_Inventory Facility Inventory] to determine function and maintenance needs.
  
During each of these inspections, inspectors must look for evidence of illicit discharges ([https://stormwater.pca.state.mn.us/index.php?title=MS4_PART_III.STORMWATER_POLLUTION_PREVENTION_PROGRAM_(SWPPP) MS4 General Permit Part III.D.3.c.]). All inspections must be documented ([https://stormwater.pca.state.mn.us/index.php?title=MS4_PART_III.STORMWATER_POLLUTION_PREVENTION_PROGRAM_(SWPPP) MS4 General Permit Part III.D.6.h.(1)]).
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During each of these inspections, inspectors must look for evidence of illicit discharges (MS4 General Permit Part III.D.3.c.). All inspections must be documented (MS4 General Permit Part III.D.6.h.(1)), so save any [[#Checklists and templates|checklists]] that you are using.
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<font size=3>'''Municipal Operations inspections required by the MS4 General Permit'''</font size><br>
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For a PDF version of this table, click [[media: Municipal Inspections.pdf|here]].
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{| border="1"
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! scope="col" width="150" | What to inspect
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! scope="col" width="50" | When to inspect
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! scope="col" width="50" |Why inspect
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! scope="col" width="500" |Examples of how-to inspect
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! scope="col" width="50" |What to document
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|-
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| Structural stormwater best management practices (BMPs) including [[Green roof fact sheet | green roofs]], [[Permeable pavement| permeable pavement]], [[Infiltration basin|infiltration basins]] or [[Infiltration trench|trenches]], [[Bioretention - bioinfiltration|raingardens]], filtration devices, sand filters, [[Hydrodynamic devices|hydrodynamic devices]], etc. [Part III.D.6.e.(1)] || Annually || To determine structural integrity, proper function, and maintenance needs ||
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*Identify clogged, overloaded, and full devices, inlets, or outlets
 +
*Identify misaligned inlets or outlets/overflow devices
 +
*Identify materials that are deteriorating and releasing pollution
 +
*Identify erosion/channelization, sedimentation, soil slides, animal burrows, undercutting, displaced riprap, or other problems
 +
*For infiltration practices that should be dry (e.g. infiltration basins, filter strips/swales) identify standing water or wet spots
 +
**If standing water is present, determine if the device is functioning as designed and meeting the 48 hour draw down requirement
 +
*Identify excess or unwanted vegetation (e.g. long-grass, tree growth)
 +
*If vegetation is designed to be present (e.g. bioretention basins, filter strips/swales), determine if the vegetation is healthy, is of appropriate size/density, and free of weeds and invasive species
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||
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*Inspection findings and date [Part III.D.6.h.(1)]
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*Dates & description of maintenance [Part III.D.6.h.(3)]
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|-
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| Outfalls where an MS4 discharges to a receiving water, or the discharge permanently leaves the MS4 [Part III.D.6.e.(2)] || Once per each permit term || To determine structural integrity, proper function, and maintenance needs ||
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*Identify erosion/channelization, scour, or other problems
 +
*Identify displaced, damaged, missing, or clogged riprap
 +
*Identify missing or damaged grates or guards, if applicable
 +
*Identify cracked, undercut, or spalled aprons, if applicable
 +
*Identify unwanted vegetation growth or decay, litter or debris, sediment buildup, or animal dens that may obstruct flow of water
 +
||
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*Inspection findings and date [Part III.D.6.h.(1)]
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*Dates & description of maintenance [Part III.D.6.h.(3)]
 +
|-
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| [[Stormwater ponds|Stormwater ponds]] [Part III.D.6.e.(2)] || Once per each permit term || To determine structural integrity, proper function, and maintenance needs ||
 +
*Identify scour, erosion/channelization, sedimentation, litter, animals burrows, undercutting, displaced riprap or other problems at/around the banks, inlets, or outlets
 +
*Identify clogged or overloaded inlets or outlets
 +
*Identify excess or unwanted vegetation (e.g. long-grass, new trees)
 +
*Identify and record materials within the device that are deteriorating and releasing pollution into the stormwater system
 +
*Determine if the vegetation looks healthy, is of appropriate size/density, and free of weeds and invasive species
 +
*Determine if there is evidence of sedimentation or erosion downstream of the outlet
 +
||
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*Inspection findings and date [Part III.D.6.h.(1)]
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*Dates & description of maintenance [Part III.D.6.h.(3)]
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|-
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| Stockpiles, and storage and material handling areas that are inventoried in the [[Facility Inventory|Facilities Inventory]] [Part III.D.6.e.(3)] || Quarterly || To determine maintenance needs and proper function ||
 +
*Identify leaking, leachate, or runoff
 +
*Identify undercut, full, clogged, ripped, broken, misplaced, askew, or other BMP maintenance needs
 +
*Install additional BMPs, such as secondary containment, impervious cover, runoff collection areas as needed
 +
||
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*Inspection findings and date [Part III.D.6.h.(3)]
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*Dates & description of maintenance [Part III.D.6.h.(3)]
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|-
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| Illicit discharges (Part III.D.3.c.&f.) || During the structural stormwater BMP; outfall; pond; and stockpile and storage and materials handing inspections || To identify and eliminate illicit discharges to the MS4 ||
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*Identify and characterize any dry weather flow
 +
*Describe the material (color, odor, sheen, froth, etc.), its effects (e.g. corrosion, pipe etching), or, if appropriate, analyze chemically
 +
*Investigate potential upstream sources that may be contributing non-stormwater flow
 +
*Record clear, unpolluted dry weather flows. If present, the discharge may be coming from unregulated sources
 +
*Inspect areas that you've identified as priority areas likely to have illicit discharges (e.g. business/industrial areas, where illicit discharges have been identified in the past)  
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|| Dates and locations of IDDE inspections conducted [Part III.D.3.h.(1)]
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|-
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| Construction activity ||  At the frequency identified in the [[MCM 4 Construction Site Stormwater Control#Example Procedures| Construction Site Inspection procedure]] for your MS4 ||  To prevent and minimize erosion to reduce the amount of sediment from entering your MS4 || 
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*Inspect for items required by the MPCA construction stormwater permit and your regulatory mechanism, some examples include:
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**Are [[Erosion prevention practices|erosion]] and [[Sediment control practices|sediment control]] and [[Construction stormwater best management practice – Vehicle Tracking|vehicle tracking]] BMPs effective, in good working condition, and able to perform their intended function?
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**Are [[Construction stormwater best management practice – Site stabilization|soils stabilized]] where needed?
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**Do pipe outlets have [[Sediment control practices - Outlet energy dissipation|energy dissipation]]?
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**Are [[Construction stormwater best management practice – Stormwater Inlet Protection|inlets protected]]?
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**Are solid and hazardous wastes contained, stored, and properly disposed of?
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**Is the contractor conducting the required site inspections?
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**Is the permanent stormwater BMP designed appropriately and protected?
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**Are temporary sedimentation basins used and with BMPs?
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**Is dewatering discharging to a sediment basin or preventing nuisance conditions?
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*Identify any potential pollution problems related to stormwater runoff or infiltration into the groundwater
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*Determine if any additional BMPs may be appropriate 
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|| [[Construction site inspection|Checklist or other written means]] to document what was inspected for [Part III.D.4.h.(1)]
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|}
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==Resources==
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===Fact sheets and guidance documents===
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*[https://www.pca.state.mn.us/sites/default/files/wq-strm4-16.pdf MPCA Managing Stormwater Sediment BMPs guidance] - Guide for properly managing sediment from stormwater systems, such as ponds
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*[https://stormwater.pca.state.mn.us/index.php?title=Documentation_requirements_and_documents_to_retain_under_the_MS4_permit Documentation that MS4 staff should retain] - List of all the documentation requirements (what information to keep, how long to keep it, level of detail to keep, etc.) for compliance with the [https://stormwater.pca.state.mn.us/index.php?title=MS4_General_Permit MS4 permit]
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===Checklists and templates===
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====BMP inspection checklists====
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*[[media:Rain_Garden_&_Bioretention_Systems_Inspection_Checklist.pdf|Rain garden/bioretention basin inspection checklist]] - University of Minnesota's (U of M) checklist for inspecting bioretention systems, such as rain gardens
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*[[media:Constructed Wetlands Inspection Checklist.pdf|Constructed wetland inspection checklist]] - U of M's checklist for inspecting constructed wetlands
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*[[media:Filter Strips and Swales Inspection Checklist.pdf|Filter strips and swales inspection checklist]] - U of M's checklist for inspecting filter strips and swales
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*[[media:Filtration System Inspection Checklist.pdf|Filtration system inspection checklist]] - U of M's checklist for inspecting filtration systems
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*[[media:Infiltration System Inspection Checklist.pdf|Infiltration system inspection checklist]] - U of M's checklist for inspecting infiltration systems
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*[[media:Underground Sedimentation Inspection Checklist.pdf|Underground sedimentation inspection checklist]] - U of M's checklist for inspecting underground sedimentation devices
 +
*[[media:Permeable Pavements Inspection Checklist.pdf|Permeable pavements inspection checklist]] - U of M's checklist for inspecting permeable pavers
 +
*[[Green roof maintenance inspection checklist]] - MPCA's inspection checklist for inspecting green roofs
 +
 
 +
====Pond inspection checklists====
 +
*[[media:Wet Ponds Inspection Checklist.pdf|Wet pond inspection checklist]] - U of M's checklist for inspecting wet ponds
 +
*[[media:Dry Ponds Inspection Checklist.pdf|Dry pond inspection checklist]] - U of M's checklist for inspecting dry ponds
 +
 
 +
====Outfall inspection checklists====
 +
*[[media:Outfall Inspection Form - Rochester.pdf|Outfall inspection checklist]] - City of Rochester's checklist for inspecting outfalls
 +
*[[media:Outfall Inspection Form - Arden Hills.docx|Outfall inspection checklist]] - City of Arden Hills' checklist for inspecting outfalls
 +
 
 +
[[Category:Level 2 - Regulatory/Municipal (MS4)]]
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[[Category:Level 3 - Regulatory/Municipal (MS4)/Guidance, outreach materials, miscellaneous information]]

Latest revision as of 16:17, 31 January 2023

image showing staff collecting data from surface water
Staff collecting water data

Municipal operation inspections

Municipal operation inspections help reduce the impacts to stormwater from municipally owned or operated facilities, areas, or stormwater best management practices (BMPs). Staff conducting these inspections can stop pollution before it reaches stormwater, or minimize the impacts if your BMPs have failed or need maintenance.

The municipal separate storm sewer system (MS4) General Permit requires inspections of the following: (MS4 General Permit Part III.D.6.e)

  • Annual inspections of structural stormwater BMPs to determine structural integrity, function, and maintenance needs.
  • At least one inspection every permit term of stormwater ponds and outfalls to determine structural integrity, function, and maintenance needs.
  • Quarterly inspections of stockpiles, and storage and material handling areas identified in the Facility Inventory to determine function and maintenance needs.

During each of these inspections, inspectors must look for evidence of illicit discharges (MS4 General Permit Part III.D.3.c.). All inspections must be documented (MS4 General Permit Part III.D.6.h.(1)), so save any checklists that you are using.

Municipal Operations inspections required by the MS4 General Permit
For a PDF version of this table, click here.

What to inspect When to inspect Why inspect Examples of how-to inspect What to document
Structural stormwater best management practices (BMPs) including green roofs, permeable pavement, infiltration basins or trenches, raingardens, filtration devices, sand filters, hydrodynamic devices, etc. [Part III.D.6.e.(1)] Annually To determine structural integrity, proper function, and maintenance needs
  • Identify clogged, overloaded, and full devices, inlets, or outlets
  • Identify misaligned inlets or outlets/overflow devices
  • Identify materials that are deteriorating and releasing pollution
  • Identify erosion/channelization, sedimentation, soil slides, animal burrows, undercutting, displaced riprap, or other problems
  • For infiltration practices that should be dry (e.g. infiltration basins, filter strips/swales) identify standing water or wet spots
    • If standing water is present, determine if the device is functioning as designed and meeting the 48 hour draw down requirement
  • Identify excess or unwanted vegetation (e.g. long-grass, tree growth)
  • If vegetation is designed to be present (e.g. bioretention basins, filter strips/swales), determine if the vegetation is healthy, is of appropriate size/density, and free of weeds and invasive species
  • Inspection findings and date [Part III.D.6.h.(1)]
  • Dates & description of maintenance [Part III.D.6.h.(3)]
Outfalls where an MS4 discharges to a receiving water, or the discharge permanently leaves the MS4 [Part III.D.6.e.(2)] Once per each permit term To determine structural integrity, proper function, and maintenance needs
  • Identify erosion/channelization, scour, or other problems
  • Identify displaced, damaged, missing, or clogged riprap
  • Identify missing or damaged grates or guards, if applicable
  • Identify cracked, undercut, or spalled aprons, if applicable
  • Identify unwanted vegetation growth or decay, litter or debris, sediment buildup, or animal dens that may obstruct flow of water
  • Inspection findings and date [Part III.D.6.h.(1)]
  • Dates & description of maintenance [Part III.D.6.h.(3)]
Stormwater ponds [Part III.D.6.e.(2)] Once per each permit term To determine structural integrity, proper function, and maintenance needs
  • Identify scour, erosion/channelization, sedimentation, litter, animals burrows, undercutting, displaced riprap or other problems at/around the banks, inlets, or outlets
  • Identify clogged or overloaded inlets or outlets
  • Identify excess or unwanted vegetation (e.g. long-grass, new trees)
  • Identify and record materials within the device that are deteriorating and releasing pollution into the stormwater system
  • Determine if the vegetation looks healthy, is of appropriate size/density, and free of weeds and invasive species
  • Determine if there is evidence of sedimentation or erosion downstream of the outlet
  • Inspection findings and date [Part III.D.6.h.(1)]
  • Dates & description of maintenance [Part III.D.6.h.(3)]
Stockpiles, and storage and material handling areas that are inventoried in the Facilities Inventory [Part III.D.6.e.(3)] Quarterly To determine maintenance needs and proper function
  • Identify leaking, leachate, or runoff
  • Identify undercut, full, clogged, ripped, broken, misplaced, askew, or other BMP maintenance needs
  • Install additional BMPs, such as secondary containment, impervious cover, runoff collection areas as needed
  • Inspection findings and date [Part III.D.6.h.(3)]
  • Dates & description of maintenance [Part III.D.6.h.(3)]
Illicit discharges (Part III.D.3.c.&f.) During the structural stormwater BMP; outfall; pond; and stockpile and storage and materials handing inspections To identify and eliminate illicit discharges to the MS4
  • Identify and characterize any dry weather flow
  • Describe the material (color, odor, sheen, froth, etc.), its effects (e.g. corrosion, pipe etching), or, if appropriate, analyze chemically
  • Investigate potential upstream sources that may be contributing non-stormwater flow
  • Record clear, unpolluted dry weather flows. If present, the discharge may be coming from unregulated sources
  • Inspect areas that you've identified as priority areas likely to have illicit discharges (e.g. business/industrial areas, where illicit discharges have been identified in the past)
Dates and locations of IDDE inspections conducted [Part III.D.3.h.(1)]
Construction activity At the frequency identified in the Construction Site Inspection procedure for your MS4 To prevent and minimize erosion to reduce the amount of sediment from entering your MS4
  • Inspect for items required by the MPCA construction stormwater permit and your regulatory mechanism, some examples include:
    • Are erosion and sediment control and vehicle tracking BMPs effective, in good working condition, and able to perform their intended function?
    • Are soils stabilized where needed?
    • Do pipe outlets have energy dissipation?
    • Are inlets protected?
    • Are solid and hazardous wastes contained, stored, and properly disposed of?
    • Is the contractor conducting the required site inspections?
    • Is the permanent stormwater BMP designed appropriately and protected?
    • Are temporary sedimentation basins used and with BMPs?
    • Is dewatering discharging to a sediment basin or preventing nuisance conditions?
  • Identify any potential pollution problems related to stormwater runoff or infiltration into the groundwater
  • Determine if any additional BMPs may be appropriate
Checklist or other written means to document what was inspected for [Part III.D.4.h.(1)]

Resources

Fact sheets and guidance documents

Checklists and templates

BMP inspection checklists

Pond inspection checklists

Outfall inspection checklists

This page was last edited on 31 January 2023, at 16:17.