2013 reissued general permit

National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS) Construction Stormwater General Permit

In August 2013, the MPCA re-issued the National Pollutant Discharge Elimination System (NPDES) State Disposal System (SDS) General Permit (R1000001) for discharges of stormwater associated with construction. See the 2013 permit under the links below.

The MPCA Citizens' Board approved this permit on June 25, 2013.

The purpose of the construction stormwater controls is to protect water resources from sediment and other pollutants.

The MPCA issues the Construction Stormwater General Permit to protect water resources from contaminants in runoff from construction sites. The general permit requires controls for construction stormwater runoff. In most cases, construction site owners and operators may apply for coverage under the general permit, meaning they agree to comply with the conditions set in the general permit.

The current permit expires on August 1, 2013. Because federal rules have changed since the last permit was issued in 2008, the MPCA updated the general permit to comply with these federal changes. Based on research and experience, the federal government continues to make changes to ensure that adequate best management practices are in place.

While the primary changes concern federal rules, the MPCA also revised the permit to clarify existing language, better align with the municipal stormwater program, address defects, and incorporate changes needed to enhance compliance with the permit.

Also, the agency will require that permit applications be submitted electronically to achieve greater efficiency.

The draft Construction Stormwater General Permit was open for public comment from Feb. 4 – March 20, 2013. The MPCA considered all comments and made revisions to the draft permit based on comments received. The new permit is provided below, followed by an outline of changes to the current permit.


Changes to the Minnesota Construction Stormwater general permit

BMPs protecting surface waters include mulch and silt fences.BMPs protecting surface waters include mulch and silt fences.

In December 2009, the U.S. Environmental Protection Agency (EPA) proposed a numeric effluent limitation in its Construction and Development rule for runoff from construction sites. The numeric limit was based on the allowable level of turbidity, which is a measure of sediment in water runoff from a construction site.

Originally, the Construction and Development rule required monitoring runoff from the site by collecting samples to test whether the site was complying with the limit. However, due to problems identified with the data used to calculate the numeric limit, the EPA delayed this requirement until new data are available. Therefore, there will be no numeric turbidity limit or monitoring and reporting requirements for turbidity in the MPCA 2013 general permit.

However, the MPCA is required to address certain enhanced Best Management Practices (BMPs) known as non-numeric effluent limitations in order to prevent the mobilization of sediment and limit the generation of dissolved pollutants from construction sites.

For more information on the Construction and Development requirements, visit the EPA website.

To comply with the federal Construction and Development rule, the MPCA plans to address the new requirements in the Minnesota 2013 general permit as follows.

Site considerations during construction

Natural vegetative buffer helps filter sediment from runoff.Natural vegetative buffer helps filter sediment from runoff.
  • Maintain a 50-foot natural buffer or use redundant sediment controls near surface waters if a buffer is not feasible.
  • Control flow rates and the total stormwater volume from the site to minimize downstream impacts.
  • Use conveyance channels to route water around un-stabilized areas, including erosion controls and velocity dissipation devices to limit the potential for erosion.
  • Direct discharges from stormwater controls to vegetated areas and use velocity devices if necessary to prevent erosion.
  • Minimize the disturbance of slopes 3:1 or steeper.
  • Initiate soil stabilization immediately by taking action as soon as practicable, but no later than the end of the next work day when earth-disturbing activities will cease for at least 14 days.
  • Minimize soil compaction and preserve topsoil at the site.
  • Temporary sediment basins outlet structure must be designed to withdraw water from the surface.
  • Sediment basins must be located outside of any natural buffers.

Design of stormwater controls

The BMPs in the Stormwater Pollution Prevention Plan (SWPPP) include requirements to control both peak flow rates and total stormwater volume at basin outlets and other water channelized from the site to minimize downstream channel and streambank erosion. Therefore, factors to be considered in design of controls include:

  • Stormwater runoff and run-on at the site.
  • Expected flow from impervious surfaces, slopes and site drainage features.
  • The expected amount, frequency, intensity and duration of precipitation.

The SWPPP will also need to address the range of soil particle sizes expected at the site.

Pollution prevention measures

Storage areas for building materials and other products must minimize exposure to stormwater.Storage areas for building materials and other products must minimize exposure to stormwater

Construction materials

  • All potential pollution generating activity locations, such as chemical storage, washout activities, fueling areas, etc. will need to be shown on the SWPPP site map.
  • Storage areas for potential pollutants on the site, such as building materials, hazardous products or materials, soaps, detergents, wastes, etc. must minimize exposure to stormwater.
  • All liquid and solid wastes generated by washout operations (concrete, stucco, form release oils, curing compounds and others) at the site must be contained for treatment or proper disposal.
  • The SWPPP must have a fueling operation plan and emergency spill plan.
  • Portable toilets on the site must be secured and sanitary waste must be properly disposed of.
Holding stormwater water in cisterns to use for irrigation is one way to retain stormwater on-siteHolding stormwater water in cisterns to use for irrigation is one way to retain stormwater on-site.

The MPCA is also considering changes to improve permanent stormwater treatment to address state anti-degradation requirements, clarify existing language, remove redundancy and enhance compliance with the permit. Notable changes include the following:

  • That all permit applications are submitted electronically with permit coverage within 7 days.
  • That trained individuals attend refresher training every 3 years.
  • There will be no change to the current requirement that site inspections occur within 24 hours of a ½-inch rainfall event.
  • That 1 inch of stormwater runoff from new impervious will be held on site via infiltration, harvesting or reuse, unless prohibited.
  • That chemicals used for purposes of flocculation will be documented in the SWPPP and that a chemical treatment plan will be included for the site.
  • That filter backwash waters are properly disposed of or returned to the beginning of the treatment process and that filter media at the site are maintained and cleaned.
  • That soils are stabilized within 24 hours for activities that are adjacent to and drain to public waters (as designated by the Minnesota Dept. of Natural Resources) with restrictions during fish spawning times.
  • The permit will allow projects located in an NPDES-permitted MS4 community to follow the current MS4 permit permanent treatment requirements.
  • The previous permit requirement for a DNR approval letter for discharges to calcareous fens was deleted from the draft permit and Appendix A BMPs applied.

See the detailed fact sheet above for more information about these changes.

Larry Zdon, 651-757-2839, Lead Permit Writer and Technical Questions. Comments, which must be in writing, should be submitted to Larry Zdon at Lawrence.zdon@state.mn.us or 520 Lafayette Road N. St. Paul, MN  55155-4194.

Brian Livingston, 651-757-2532. Supervisor

March 8, 2013: Public notice meeting. 9 a.m., MPCA Citizens' Board Room, lower level, 520 Lafayette Road N. St. Paul, MN.

March 20, 2013: Deadline to submit comments on draft Construction Stormwater General Permit. Interested persons are invited to submit written comments on the draft permit. Any comments received before 4:30 p.m. on March 20 of the comment period will be considered before the draft permit is finalized. Comments on the draft permit should include the following information, pursuant to Minn. R. 7001.0110:

  • A statement of the person’s interest in the draft permit.
  • A statement of the action the person would like the MPCA to take, including specific references to sections in the draft permit; and
  • The reasons supporting the person’s position, stated with sufficient specificity as to allow the Commissioner to investigate the merits of the person’s position.

Submit comments, which must be in writing, to Larry Zdon, 520 Lafayette Road N. St. Paul, MN  55155-4194.

March 26, 2013: MPCA staff members are scheduled to present the draft Construction Stormwater General Permit as an informational item to the MPCA Citizens' Board meeting.

June 25, 2013: MPCA staff are scheduled to ask the MPCA Citizens' Board to approve the draft Construction Stormwater General Permit at this meeting.

August 1, 2013: Current permit expires. Deadline for re-issuing updated permit.

Under the federal Clean Water Act and Minnesota law, the MPCA oversees a program to manage stormwater runoff from construction activities:

  • These activities include clearing, excavating and grading that significantly disturb soil. Without proper controls, a construction site can lose 20 to 150 tons of soil per acre to stormwater runoff, according to the U.S. Environmental Protection Agency. Studies have shown that for every $1 not spent on erosion control, $14 to $15 is spent on correcting the impact. Prevention is a sound investment, especially with Minnesotans investing millions in Clean Water Legacy Amendment funding into natural resources.
  • The purpose of the state program is to protect water resources from contaminants, particularly sediment, as well as nutrients, oil, chemicals and litter carried with runoff.
  • In addition, the program strives to prevent this runoff from flooding streams and lakes as well as damaging habitat for fish and wildlife.

Construction sites need to control the volume of water as well as discharge rate and contaminant levels to protect lakes and streams from pollution:

  • Research shows that settling out sediment and other contaminants is just the first step.
  • Controlling the discharge rate leads to less erosion from a site.
  • Controlling the volume of water leads to less impact downstream such as filling in lakes and wetlands, eroding streambanks, and damaging habitat for fish and wildlife.

Improper controls on construction stormwater can result in large amounts of sediment and other contaminants washing into storm sewers that drain to lakes and rivers.

Mulch and silt fences are some of the tools that construction sites can use to control stormwater and protect water resources. Minnesota is updating its general construction stormwater permit to comply with changes on the federal level.

The PDF icon Minnesota NPDES/SDS Construction Stormwater General Permit, which incorporates several changes, will go into effect August 1, 2013. This reissuance has prompted several questions from regulated parties. Here are the MPCA responses to some of the Frequently Asked Questions about the permit so far.

Question: For projects already planned but yet to apply for a permit, does the 2008 or 2013 permit apply to the project?

MPCA response: The date that the MPCA receives an application will determine whether a project design must incorporate and follow the conditions of the 2008-2013 or the 2013-2018 Construction Stormwater (CSW) General Permit.

If the MPCA receives the application prior to midnight July 31, then the project will be authorized under the permit in effect at that time, which is the permit dated Aug. 1, 2008. The project Stormwater Pollution Prevention Plan (SWPPP) will be required to meet the conditions and requirements of the 2008 CSW permit. On Aug. 1, 2013 the 2008 permit will expire and any ongoing permitted projects will automatically be covered under the reissued 2013 CSW permit. A provision in the 2013 CSW permit (Part I.A.4) allows permittee(s) originally authorized under the 2008 CSW permit 18 months (until Feb. 1, 2015) to amend their SWPPP to the new standards for sediment and erosion control (and some administrative requirements) during construction. However, the project does not need to upgrade to the new permanent stormwater treatment requirements of the 2013 CSW permit. 

If the application is received after 12:01 am August 1, 2013, then the applicant will be applying for the permit that is in effect at that time, which is the permit dated August 1, 2013 – August 1, 2018. The SWPPP for the site, and the activities on the site would need to be in compliance with the 2013 permit.

Applicants may apply for project coverage early (before Aug. 1) to take advantage of the 18-month transition time the agency is providing permittees, even though a project may not start for a number of months after the application date. Applicants applying for coverage in advance of construction start date still must have a complete SWPPP at the time of application. The MPCA does random audits of permits to ensure SWPPPs are complete. If the MPCA finds a site without a complete SWPPP, then the agency may determine the site has an invalid permit application and is thus out of compliance with the permit, which may result in enforcement action.

Question: I see that the MPCA will require online permit applications – no paper applications – starting Aug. 1. What about permit applications mailed July 31?

MPCA response: The majority of permittees already use the agency’s online application service. The online application service is much more efficient for both regulated parties and the agency. The MPCA covers 1,000-2,000 sites a year under the general construction stormwater permit.

If you plan to submit a paper application, then you need to notify the MPCA in advance. Otherwise, mailed or delivered paper applications will be rejected if received after July 31. 

The agency does grant waivers to the online application process. Those seeking a waiver from the online system and wanting to submit a paper application need to contact the agency in advance for each site (the agency recommends 3 weeks to ensure mailing forms received by both permittee and then the agency). For pre-approval of paper applications, call the MPCA at 651-757-2532. Note that the paper application will take longer than the electronic application and permit coverage will not take effect until 7 days after received by the agency.

Please note this change in the online application system. The permit coverage date, which allows construction to commence, will be 7 days (not 2 as in the previous permit) for applications submitted online.

Also, sites 50 acres or larger discharging within one mile and to a special or impaired water still need to provide their SWPPP to the agency for a 30-day review.