Spring 2022

• Important MS4 permit reminders!
• New model ordinance available for MS4 permittees
• How Stormwater BMPs helped delist impaired waters
• Why trees matter
• Join Minnesota GreenCorps!
• Events

Important MS4 permit reminders!

If you are an MS4 permittee covered under the 2020 MS4 General Permit, please remember the following:

1. MS4 Annual Report for calendar year 2021 is due June 30, 2022.
2. All new 2020 MS4 General Permit requirements must be met within 12 months from the date permit coverage was extended to your organization. The MPCA extended permit coverage to most permittees in the fall of 2021. The exact date can be found on your notice of permit coverage cover page. Some notable new requirements include:
   • Regulatory mechanism (e.g., ordinance, rule, contract language) to meet water quality volume treatment requirements in MCM 5: Post-Construction Stormwater Management
   • For cities, townships, and counties: a regulatory mechanism to address pet waste
   • For cities and townships: a regulatory mechanism for proper salt storage
   • Public education on deicing salt and its impact on receiving waters
   • Winter maintenance staff training
   • Winter snow and ice management policy
   • Permittees with an applicable Total Maximum Daily Load (TMDL) waste load allocation (WLA) for chloride must document the amount of deicer applied during the winter maintenance season and conduct an assessment of their winter maintenance operations
   • Permittees with an applicable TMDL WLA for bacteria must inventory potential sources and develop a written plan to prioritize reduction activities for those sources
   • Permittees with an applicable TMDL WLA for temperature must develop a written plan to reduce thermal loading

For a more comprehensive look at the new requirements, please see the 2020 MS4 General Permit with "highlighting" of new requirements, available here. If you have any questions, please contact your assigned MPCA staff member.

New model ordinance available for MS4 permittees

In early May, the MPCA released its “Model” MCM 4 and MCM 5 regulatory mechanism guidance (wq-strm4-98). MS4 permittees covered under the 2020 MS4 General Permit may use this guidance to assist in the development of their regulatory mechanism(s) to meet the associated requirements of MCM 4: Construction Site Stormwater Control and MCM 5: Post-Construction Stormwater Management. This guidance document is available for download at https://www.pca.state.mn.us/water/complying-ms4-general-permit.

How Stormwater BMPs helped delist impaired waters

Every two years, the MPCA compiles a list of water bodies in Minnesota that don’t meet water quality standards because of various pollutants. This list is then submitted to EPA for approval. In 2022, MPCA proposed adding 305 water bodies with 417 impairments to the list (a waterbody can be polluted, or impaired, by more than one pollutant). This brings the total number on the list to 2,904 water bodies with 6,168 impairments. Another section of the list keeps track of waterbodies that have improved to the point that they are meeting water quality standards again, which are then ‘delisted’. 173 waters, both lakes and streams, have been delisted since 2002, with 47 waterbodies delisted in 2022 alone.

We can drill down to specifically look at nutrient impaired lakes within regulated stormwater communities. 188 nutrient impaired lakes are within, or intersect, regulated stormwater communities. Of those, 30 are now delisted. Part of the delisting process includes providing a reason for delisting. Restoration activities were given as a reason for delisting in 24 of those 30 lakes. Several MS4s took pro-active efforts using a range of BMPs to improve water quality. Examples include the following:

The City of St. Cloud implemented a nutrient reduction plan to address Lake George water nutrient impairments. The 135-acre watershed of Lake George had very little existing stormwater treatment. Initially, the city implemented shoreland restorations using native plantings and installing rain gardens around the lake. Then the city dredged Little George to remove sediments and added iron filings as part of a U of M study to address phosphorus. More recently in 2018-2020, the city implemented a series of alum treatments and also installed an underground stormwater treatment system in a parking lot that drains to the lake. The city has implemented an ongoing citizen education and awareness program for the watershed, including an Adopt-a-Drain program to engage citizens in cleaning up stormwater discharges.

The City of Eagan conducted similar projects to address LeMay Lake phosphorus impairments during 2015-2020. Initially, the city conducted alum applications to the lake and later installed an iron sand filtration system to treat stormwater.  Most recently an underground infiltration system was installed to reduce pollutants reaching the lake. The projects resulted in an estimated Total Phosphorus Waste Load reduction of 114.5 pounds of phosphorus per year.

Sherburne County SWCD undertook a project in 2015 to identify sources of phosphorus in the Birch Lake sub-watershed and was awarded a State of Minnesota Clean Water Funds grant to address the sources causing excessive algae blooms in the lake. The SWCD worked with private landowners to restore shorelines and implement other stormwater improvements. The Township installed several infiltration basins near the lake. As a result, the lake is now meeting water quality standards and the SWCD plans to continue to work on addressing sources, such as agricultural runoff, to keep it that way.  

Sherburne County SWCD infiltration ditch

Why trees matter

Incorporating trees into urban development has multiple benefits. Preserving mature trees on properties slated for new development or planting new trees for use in certain applications can help meet MPCA’s stormwater volume reduction requirements as well as reduce some of the negative effects of increased development. Trees have the ability to provide multiple benefits to communities, including improved air quality, reduced stormwater runoff, pollutant removal, wildlife habitat, sequestering atmospheric carbon, increased property value, aesthetics and they provide a greater sense of well-being to the community. Trees also provide shade and wind protection that reduce building energy consumption and urban heat island effects.

In recent years, Minnesota has seen significant increases in rainfall intensity and volume in many communities due to climate change. Check out the Minnesota’s Department of Natural Resources Climate Trends Tool to see how rainfall totals have changed overtime in your community. Trees provide greater resilience to increased rainfall. Increasing tree canopies can help reduce flooding in flood-prone communities by intercepting and removing large quantities of rainwater.  As an example, one native hackberry tree planted 20 years ago will intercept 6,296 gallons of rain, absorb 1,056 pounds of atmospheric carbon dioxide and capture 1,829 gallons of stormwater runoff. Use of native trees is preferred and they should also be selected based on their ability to survive future climate conditions.

Street lined with trees in Minneapolis with new constructed tree infiltration trenches-Photo courtesy of MNDOT

Trees also can be incorporated into stormwater BMP treatment trains as discussed in Minnesota’s Stormwater Manual for meeting volume reduction requirements of the MPCA NPDES/SDS General Construction Stormwater permit. Tree trenches and tree boxes can be retrofitted into existing impervious areas, such as parking lots and boulevards, to improve stormwater retention or included in the design of a new stormwater management system where soils limit the use of inground infiltration systems.

Join Minnesota GreenCorps!

Minnesota GreenCorps, an AmeriCorps program coordinated by the Minnesota Pollution Control Agency, is seeking motivated, service-minded individuals to improve the environment and strengthen communities throughout the state.  MN GreenCorps members serve with government entities, non-profit organizations, and educational institutions to carry out service projects in areas of air pollutant reduction, community readiness and outreach, waste reduction, recycling, and organics management and green infrastructure improvements - including forestry and stormwater. MN GreenCorps members serving on green infrastructure improvements may focus on stormwater activities such as: Inventorying and assessing existing stormwater best management practices. Identifying opportunities and implementing green infrastructure practices (rain gardens, permeable pavement, bioswales, green roofs, etc.) Mobilizing volunteers to improve public lands. Identifying chloride management strategies and providing guidance on proper salt application. Providing education about the benefits of stormwater practices and pollution prevention. Conducting surveys to measure participant knowledge gains and behavior change. MN GreenCorps members serve full-time for 11 months, from September to August. In addition to receiving training, developing job skills, and gaining professional experience, members earn a living allowance of $1,027.08 (pre-tax) paid every two weeks, health insurance, student loan forbearance, and an education award of up to $6,495. Visit the MPCA’s Minnesota GreenCorps webpage to learn more and apply by June 16!

Events

• June 16: MS4 Outreach/Question & Answer Session  Pollutant reduction credits, how are they calculated, used, and why are they important. 9:00AM-11:00AM
• June 27-29^th: WEF Stormwater Summit in Minneapolis. Register here
• June 23, 2022: University of Minnesota Stormwater Speaker Series- David McCarthy.  Real time monitoring and control of green infrastructure for improved stormwater management. 4:00PM-6:00pm
• August 2-3, 2021: Salt Symposium 2022 
• See the Events page in the Minnesota Stormwater Manual for additional events.

Newsletter contact

If you have questions about or suggestions for this newsletter, contact Roberta Getman, MPCA-Rochester, 507-206-2629.