Future updates

Timelines shown below are approximate. We update this page infrequently.

Information: Updated March 15, 2019

TMDLs

The work includes the following.

1. Develop and enhance guidance and resources for permittees to evaluate TMDL-related permit compliance. This would include developing guidance for more robust modeling tools and general monitoring guidance that permittees could use to assess:

• Baseline pollutant loading
• Current pollutant loading
• Cumulative estimated reductions

2. Develop outreach, training, and/or workshops to accompany these resources.

To view the workplan - File:Wiki work plan TMDLs.docx

Pretreatment

• Provide information on design criteria and design considerations, construction guidelines, and maintenance recommendations for pretreatment settling practices. This includes proprietary and non-proprietary practices, including forebays. Includes photos, schematics, details or CAD drawings, and other images as necessary or appropriate.
• Provide general information and design, construction, and maintenance guidance for level spreaders. Ensure the information is consistent with information on pretreatment filter strips and pretreatment settling practices.
• Provide 5 to 7 case studies summarizing the use of pretreatment practices, including at least one case study for each of the following practices.
• Vegetated filter strip
• Forebay
• Proprietary settling device
• Screen

See workplan - File:Wiki pretreatment workplan.docx

We are also executing a new work order to provide recommendations to the MPCA on sizing criteria for different types of pretreatment practices (e.g. forebay, filter strip, proprietary devices). These recommendations can be based on information in the literature, monitoring data, and/or from correspondence with stormwater practitioners. Work order ends June 30, 2019.

See workplan - File:Pretreatment sizing selection and iron treatment updates - Scope of work.docx

Construction stormwater

Update existing information and provide new information on active construction site erosion prevention and sediment control, including general and technical information on BMPs. Potential BMPs include the following.

• Temporary Sediment Traps and Basins
• Stabilized Earth/Soil Berm, including wood chip berm
• Buffer Zones
• Lined Channels
• Riprap
• Temporary stream crossing
• Dewatering (6.40), including
  • Chemical Treatment
  • Sediment Filtration

See workplan - File:Wiki Construction SW workplan.docx

MS4 Accelerated Implementation – Stormwater Case Studies

Develop and disseminate information on case studies of water quality projects for Municipal Separate Storm Sewer System (MS4) permittees. The case studies cover a range of MS4 permit issues and types of MS4s (cities, townships, colleges, watershed districts/watershed management organizations).

See workplan - File:Wiki case study work plan.docx

Phosphorus export from constructed ponds

Studies show that constructed stormwater ponds can export phosphorus. We will execute a work order to compile existing information on phosphorus dynamics in ponds, conditions that result in phosphorus export, and recommended design, construction, and maintenance practices. NOTE this is an area where further research is needed, and the information obtained through this work order is likely to be limited by knowledge gaps on this topic.

See workplan - File:Wiki phosphorus export work plan.docx

Pond assessment guidance for MS4 permittees

See workplan - File:Wiki pond assessment workplan.docx

Update the Blue Star Assessment Tool

See workplan - File:Wiki Blue Star workplan.docx

Credits for street sweeping

Develop a framework and communication-outreach plan for a method to credit street sweeping that can be implemented by Municipal Separate Storm Sewer (MS4) permittees to help meet permit requirements.

See workplan - File:Street sweeping work plan for wiki.docx

This work will be expanded in 2019 to include final development of the credit system and subsequent outreach and communication.

Improved information on suitable engineered media for bioretention practices

Develop materials, for incorporation into the Minnesota Stormwater Manual, on the topic of phosphorus retention by bioretention media and media components. The materials include documentation of local sources, simple tests or metrics, and/or design specifications that can be used by practitioners to reliably and repeatably obtain a biofiltration practice that removes and does not leach phosphorus and functions as expected.

This work will be completed in two phases and coordinated with research being conducted by the University of Minnesota. Phase 1 focuses on identifying materials that potentially may be used in biofiltration practices. The work plan for Phase 1 is below.

Phase 2 focuses on providing detailed information for each of the materials identified in Phase 1. We anticipate Phase 2 beginning in early summer.

Other topics of interest

We are pursuing opportunities to address the following topics, with the goal of developing guidance for the stormwater manual.

• Improved guidance for iron enhanced stormwater practices
• Building stormwater education material, particularly as it relates to MS4s, into the manual wiki
• Getting sizing information for pretreatment practices

On-going work being done by MPCA staff

Green infrastructure for stormwater management

We have created a portal page containing links to pages addressing Green Infrastructure. We continue to work on pages associated with this topic.

Road salt

We continue updating information on road salt as time allows.