Stormwater News — October 2016

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October 2016

Welcome to the first edition of Stormwater News, the official newsletter of the MPCA’s stormwater program. The newsletter will be delivered quarterly, and provide:

  • Stormwater Manual updates and other guidance materials
  • program and regulatory updates
  • research news
  • success stories
  • funding opportunities
  • innovative approaches to permit compliance
  • training offerings
  • and more …

The newsletter will contain information on municipal, construction, and industrial stormwater and will replace the Stormwater Manual newsletter. Subscribers to the MPCA’s municipal stormwater, construction stormwater, and stormwater manual news lists will be receiving this newsletter four times a year. Industrial stormwater subscribers will continue to receive a separate Industrial Stormwater newsletter, which has more in-depth information on that sector. 

About the MPCA’s stormwater programs

The MPCA administers the requirements of the federal Clean Water Act in addition to its own State Disposal System requirements. At the MPCA, the Stormwater Program includes three general stormwater permits: the Municipal Separate Storm Sewer Permit, the Construction Stormwater Permit, and the Industrial Stormwater Permit. Each program administers a general permit (and in some cases, individual permits) that incorporates federal and state requirements for Minnesota stormwater management. Each program also offers guidance and assistance. 

Preparing your construction site for winter snow melt and rain

Set up your BMPs before winter starts!

The construction season is coming to a close. Set up erosion and sediment control measures on your site before the ground freezes, so they offer protection during winter thaws, rain events, and the spring snow melt. Don’t risk water quality violations!

Construction site fall prep

Stabilize all exposed soils with mulch or other cover and plant seed for early spring. 


Remove sediment deltas.

Construction site fall prep 5
Construction site fall prep 2

Stabilize ditch bottoms with appropriate BMPs.


Clean sediment traps.

Construction site fall prep 4
Construction site fall prep 6


Clean sediment from streets and gutter systems.


Repair non-functioning BMPs

Construction site fall prep 3

Operating in frozen conditions

If construction work is suspended due to frozen conditions, the site inspections can be suspended too. However, if snow melt or precipitation causes runoff during the winter months, the inspection and maintenance schedule must resume within 24 hours after the runoff occurs. If construction resumes during frozen conditions, inspections must resume 24 hours prior to resuming the construction and continue while construction is active. Install erosion and sediment control measures on the same timelines required during non-frozen conditions, but the installation method and type of BMPs may change. For example, hydro mulches can’t be used on snow, but straw mulch can. Instead of staking and trenching in silt fence, use weights to adhere it to the ground or use rock logs as perimeter control.

Municipal separate storm sewer system (MS4) permitting update

After the Census Bureau released its 2010 data, MPCA identified several communities and public facilities that appeared to meet the criteria for MS4 permitting. MPCA staff worked with these entities and determined that 25 will receive coverage under the MS4 permit.

Bayport MS4

The City of Bayport is one of 25 communities that will receive coverage under the MS4 permit based on results of the 2010 Census.

Over the past 18 months, MPCA staff have provided technical assistance and information to these 25 new applicants as they develop stormwater pollution prevention program (SWPPP) documents. The MPCA also partnered with University of Minnesota Extension to present workshops to the new applicants on general stormwater management topics and a short course specifically tailored to townships.

Stormwater Manual updates

Several pages have been created or updated since the most recent newsletter, and several sections of the manual are undergoing updates this fall.

  1. Pretreatment— Section was updated and includes general information for pretreatment settling devices, pretreatment screens, and pretreatment vegetated filter strips.
  2. Infiltration practices (includes infiltration basins, infiltration trenches, underground infiltration, and dry wells) — The design, construction, and operation and maintenance pages have been updated. New pages address types of infiltration, case studies, and information on collecting and interpreting soil borings.
  3. Stormwater and rainwater harvest and use/reuse — Section in development and scheduled to be completed this fall.
  4. Construction stormwater — Section reorganized and includes information on erosion prevention practices and sediment control practices. Each of these sections is undergoing development and should be completed this fall. We’ve also begun adding photo galleries for construction practices.
  5. Stormwater infiltration, contaminated soils, and groundwater — See two new pages: Contaminated sites and stormwater infiltration and Screening assessment for contamination at potential stormwater infiltration sites
  6. Pollinator-friendly BMPs — Find information on designing and implementing pollinator-friendly stormwater BMPs.
  7. Virtual tours — See links to Minnesota organizations with virtual tours or good maps of their stormwater BMPs.

Estimate soil infiltration rates with proper soil borings

Stormwater runoff captured by an infiltration best management practice (BMP) must infiltrate into the underlying soil within 48 hours. Properly designing an infiltration BMP therefore depends on obtaining accurate information on soil infiltration rates. Getting the soil infiltration rate wrong at a site can lead to increased cost and likely failure of the BMP.

Unfortunately, soils vary greatly in their infiltration properties, even within a specific soil type over very short distances. Ideally, soil infiltration rates are determined in the field using an infiltrometer, permeameter, or other appropriate method. More often, borings are utilized to identify soil type and an infiltration rate is associated with that soil type.

The Minnesota Stormwater Manual contains a new page discussing the collection and interpretation of soil borings for infiltration BMPs. The manual includes the following caution:

Objectives for collecting soil borings for stormwater infiltration practices differ from objectives for collecting borings for structural engineering purposes. Identification of low permeability or restrictive layers in soil are critical to proper design and construction of infiltration practices.

The new manual page discusses important considerations for collecting and interpreting soil borings, number to collect, what to do when sample recovery is low, how to identify a confining layer, and more. The page includes sample boring logs, summary tables, images, references, and links to additional information. If you use soil borings in the design and construction of stormwater infiltration BMPs, the new manual page should be valuable to you.

Minnesota GreenCorps members improving stormwater management

GreenCorps and stormwater

Since the Minnesota GreenCorps program began in 2009, 30 GreenCorps members have served in the “Green Infrastructure: Stormwater” track at host sites throughout Minnesota. Cities, watershed districts, universities, and nonprofit organizations have benefited from the work of GreenCorps members, several of whom have enter the workforce with their host sites or as stormwater managers in other capacities.

GreenCorps members help organizations lead projects that they couldn’t have otherwise implemented and work with regulated municipalities to go above and beyond requirements or improve their communities. This year, there are three members whose main focus is stormwater. Erica Strom is working with the City of Duluth and the Regional Stormwater Protection Team to develop programs to encourage responsible salt application and chloride pollution reduction. Shanti Penprase is supporting the Freshwater Society’s expansion of its popular Master Water Stewards program to a statewide audience. Leah Weston is helping the City of Faribault inventory stormwater practices within city boundaries and conduct outreach on stormwater issues.

If your organization may be interested in employing a Minnesota GreenCorps member, go to the MPCA web site and sign up to be notified about future opportunities.

Stormwater and solar farms

Solar farm

Minnesota has recently experienced a surge in solar-farm construction as renewable energy becomes more popular. The MPCA has developed guidance on stormwater management to address the unique characteristics of solar farms and to help designers, engineers, and contractors comply with the MPCA’s Construction Stormwater General Permit requirements. The agency also offers additional stormwater and landscape guidance for solar farms. For more information, call the MPCA at 651-296-6300 or 1-800-657-3864 and ask for Construction Stormwater staff.

MPCA stormwater research projects

Stormwater research

The Stormwater Program is involved in several research projects that look at pollutant removal by stormwater BMPs and other stormwater management questions. The projects include:

  • Iron-enhanced filtration — In partnerships with two cities and a watershed district, we’re examining the effectiveness of five iron-enhanced stormwater treatment systems: two sand filters, a biofiltration system, and two detention ponds retrofits.
  • Infiltration monitoring — The MPCA is partering on two projects that monitor infiltration systems at four sites to assess pollutant transport and removal within the BMP and in the unsaturated soil zone underneath. The sites include surface and underground infiltration practices.
  • Daphnia ecotoxicogenomics method development and calibration — Researchers are investigating the viability and value of using a daphnia-based transcriptomics tool as part of MPCA's water quality monitoring efforts.  
  • Contaminants of emerging concern (CECs) in stormwater — MPCA and several partners are investigating CECs and associated toxicology in stormwater conveyances and iron-enhanced sand filters in the Twin Cities area. Researchers are measuring more than 300 commercial/industrial chemicals and the effectiveness of full-scale iron-enhanced sand filters at mitigating their impact.
  • Infiltration in roadside swales: Long-term field testing prototype — MPCA and MnDOT are prototyping a method to assess the long-term infiltration performance of swales in natural conditions at various scales.
  • Stormwater research priorities and pond maintenance — The MPCA, serving as the state’s technical liaison, is assisting the University of Minnesota in looking for ways to improve stormwater pond maintenance and performance. This project will also produce a ten-year framework of stormwater research needs, and provide for education and training to disseminate the results.

When appropriate, data from these projects will be aggregated for analysis with Twin Cities area data available from other sources to achieve broader representation. These projects are possible through much-appreciated partnerships and Clean Water Funds and, for one project, an EPA grant. As each is completed, MPCA will provide summaries in this newsletter, with full reports available through the Stormwater Program web site and manual. For more detailed information on these projects, visit the Minnesota Stormwater Manual.

Industrial stormwater

The industrial stormwater program regulates 29 industrial sectors, including manufacturers, recyclers, transporters, landfills, and wastewater treatment plants. The program offers guidance, assistance, and regulatory compliance to regulated industries, and even offers facility-specific stormwater management suggestions from their engineer. The program has created several short YouTube training videos, guidance manuals, and a self-audit “inspector’s checklist” document. To learn more or to view these guidance materials, go to the industrial stormwater home page.  

This summer, the MPCA’s Industrial Stormwater Program worked with interns who spent part of their internship experience working with regulated stormwater facilities. Additionally, the Minnesota Technical Assistance Program highighted this year’s interns, whose focus included waste reduction, stormwater conservation, and lean manufacturing. Read all about these developments, as well as the latest about the Nonmetallic Mining (MNG49) permit update in the September 2016 Industrial Stormwater News quarterly newsletter. 

Meet the MPCA stormwater staff

Marni Karnowski is Section Manager for MPCA's Municipal Stormwater Program, which is responsible for permitting, compliance and enforcement, assistance, communications, TMDL implementation, and research associated with Municipal Separate Stormwater Sewer Systems (MS4s) and construction stormwater sites. 

Ryan Anderson supervises the research, engineering, and outreach unit; staff include David Fairbairn, Mike Findorff, Anne Gelbmann, Paul Leegard, Logan Quiggle, Todd Smith, and Mike Trojan

Tanya Maurice supervises the construction stormwater unit; staff include Dave Bodovinitz, Brandon Dahl, Amy Delbecq, Jim Dexter, Paul Erdmann, Roberta Getman, Nicholas Nistler, and Jeremy Sanoski.

Duane Duncanson supervises the municipal stormwater unit; staff include Scott Fox, Brian Green, Megan Handt, Cole Landgraf, and Joshua Stock

Stormwater Manual webinars

Over the past year, a lot of new information has been added to the Minnesota Stormwater Manual. The MPCA hired consultants to update guidance on pretreatment, infiltration, construction stormwater, and harvest and re-use. MPCA staff will be setting up a series of webinars on this new guidance. Our first webinar on infiltration will be on Thursday, December 8 at 1:30 p.m. Save the date!    

Newsletter contact

If you have questions about or suggestions for this newsletter, contact Anne Gelbmann, MPCA-St. Paul, 651-757-2384