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Minnesota Stormwater Manual

Guidance for completing the MS4 Permit TMDL Application Form
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Information: There will be an hourlong webinar every other Tuesday from 9-10am

regarding the TMDL Application Form. Each webinar will cover a specific topic. The March 9th webinar topic will discuss how to address categorical wasteload allocations in your TMDL Application Form. March 23rd will be a general question and answer session. April 6th's topic is to be determined.

Please submit topic ideas or questions to Anna Bosch at the MPCA. Previous webinars are recorded and can be found here.

[Webex Link for Tuesday webinars] Meeting number (access code): 187 134 7033 Meeting password: Dn9GZeh6se9
Video overview of the MS4 Permit TMDL Application Form

This page provides guidance for completing the Municipal Separate Storm Sewer System (MS4) Permit TMDL Application Form. Completing and submitting this form is a requirement for permittees who have Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for total phosphorus (TP), total suspended solids (TSS), oxygen demand, or nitrate.

Description of the form

Each MS4 Permit TMDL Application Form is a custom created workbook for each permittee with United States Environmental Protection Agency (USEPA) approved Total Maximum Daily Load (TMDL) wasteload allocations (WLAs). The workbook consists of eight tabs. Three tabs are informational - for the permittee to reference in order to complete the MS4 Part 2 Permit Application, or to reference while completing the other five tabs in this workbook.

Information tab

General instructions on how to complete the form, and reference links.

Screenshot of Municipality X Applicable WLAs for Bacteria, Temperature or Chloride
Image of Applicable Bacteria, Temperature or Chloride WLAs for Municipality X. Click on Image to enlarge

Bacteria Chloride Temp tab

Informational tab- lists any applicable WLAs for bacteria, chloride or temperature TMDL projects (USEPA approved, more than a zero % reduction). Use the information in this tab to answer questions 141, 146 and 151 in the MS4 Part 2 Permit Application. If there is not a project listed for any certain pollutant, you would check the 'No' box for the corresponding question(s) in the MS4 Part 2 Permit Application.

Applicable WLAs determination tab

This tab includes two separate lists. The list in Column A contains any applicable WLAs (USEPA approved, more than a zero % reduction) for oxygen demand, nitrate, TSS, or TP TMDL projects. They are listed by TMDL project name-waterbody-(waterbody id)-pollutant. Column F lists the corresponding applicable numeric WLAs for those projects. If Columns A and F do not show any projects, you do not have any applicable WLAs, and you do not need to complete the TMDL Application. The list of permittees who have no applicable WLAs are located here. Otherwise, the applicant needs to make a determination if they are meeting each WLA or not and type 'Yes' or 'No' in Column B. Once the determination is made, there is a macro that needs to run, and this will autopopulate the rest of the workbook.

Warning: THE YES/NO DETERMINATION IN COLUMN B MUST BE COMPLETED ON THIS TAB BEFORE ANY OTHER TAB IS COMPLETED
  • Applicable WLAs Determination tab screenshots and Decision Tree. Click on an image for enlarged view.
  • Screen shot Applicable WLAs tab before determination is made

    Screen shot showing Applicable WLAs determination tab before making the determination.

  • Screen shot Applicable WLAs tab after determination is made

    Screen shot showing Applicable WLAs determination tab after making the determination.

  • decision tree for TMDL application form

    Decision Tree for TMDL application form. If you have multiple applicable TMDL projects, you may be meeting some wasteload allocations, and not be meeting others. Depending on your determination, you may complete four tabs, or only two.

In order to complete that determination, the following will be needed:

  • An inventory of structural stormwater BMPs and non-structural BMPs (e.g. establish ordinance, education and outreach, illicit discharge elimination, etc.) within the watershed boundary to the impaired water and that are being applied toward meeting the WLA(s). To determine watershed boundaries see the specific TMDL report or retrieve shapefiles from the MPCA.
  • An estimate of annual cumulative pollutant load reductions (pounds or percent) for implemented BMPs.
  • An estimate of pollutant loading rates (lb/ac/yr) to the impaired water.
Screenshot of Compliance Schedule tab
Screenshot of example Compliance Schedule Tab, before filling in schedule.

Compliance schedule tab

This tab needs to be completed for each WLA that is not being met. Permittees will fill in the target year that each of the applicable WLA(s) will be achieved for each TMDL- waterbody- pollutant project listed in column A. If there is an applicable WLA for total suspended solids (TSS) or total phosphorus (TP), a cumulative estimate of TSS and TP load reductions to be achieved during the permit term and the method used to determine the estimate should be entered in Columns D and E.

Compliance schedule BMPs tab

Screenshot of Compliance Schedule BMPs tab
Screenshot of example Compliance Schedule BMPs Tab, before filling in BMPs.

This tab will be filled in with proposed best management practices (BMPs) or progress toward implementation of BMPs to be achieved during the permit term, anticipated number of practices (if the permittee is planning to install more than one of any type of BMP), and the year each BMP is expected to be implemented ("Implementation Year(s)" column). Put an "X" in the boxes for the TMDL that corresponds with each BMP. This tab is primarily for planned practices. Previously installed BMPs will be captured through future Annual Reporting.

Reductions for WLAs met tab

Screenshot of Reductions for WLAs met tab
Screenshot of example Reduction for WLAS Met Tab, before filling in reductions.

This tab requires the permittee to submit required information for each applicable oxygen demand, nitrate, TSS and/or TP WLA they are claiming to meet. This substantiation needs to be completed using an MPCA-approved method. This should either demonstrate the cumulative estimated reductions from BMPs that serve to meet the MS4 WLA reductions included in the TMDL report OR demonstrates the MS4's existing load meets the WLA.

BMPs for WLAs met tab

Screenshot of WLAs met BMPs tab
Screenshot of example WLAs met BMPs Tab, before filling in BMPs.

This tab requires the permittee to submit required information for each applicable oxygen demand, nitrate, TSS and/or TP WLA they are claiming to meet with a list of all stormwater BMPs implemented to achieve the applicable WLA. For structural BMPs, it is required to include the BMP type, year implemented, location in geographic coordinates (x coordinate and y coordinate), and owner.

Master list tab

This table is for reference only and shows ALL waste load allocations assigned to an MS4 and all flow zones, whether they need to be reported on in the TMDL application or not. This is a filterable list, and can be changed to show other permittees, projects, etc.

FAQ

1. For categorical WLAs – Are MS4 communities to report on BMPs in just their community, or do they also present data from other communities in the watershed to demonstrate compliance or progress towards the categorical WLA?

  • Please see guidance at Guidance for categorical TMDLs. If the communities have agreed to work together, then data from other communities would be presented. If not, determine the permittee’s portion of the categorical WLA and present data towards that.

2. For categorical WLAs – Can private BMPs constructed in the watershed that have an overall pollutant reduction be included?

  • Refer to the specific TMDL’s WLA methodology, in case certain areas have been excluded from the WLA; but generally, if it discharges to the conveyance system within the watershed, it should be creditable.

3. For the Compliance Schedule BMPs tab- should it only include BMPs that have yet to be implemented/installed or should it include already installed BMPs?

  • It is allowable to include recently installed BMPs that have not yet fully reached their peak removal efficiency, or that will be improved upon over the permit cycle in your compliance schedule. (Enter them as implemented in 2020). Ultimately, the appropriate time to identify already implemented BMPs for WLAs not being met is when you complete the TMDL annual report form.

4. My Applicable WLAs Determination tab shows the percent reduction in Column I as "Not Available". Does that mean I don't have to report on that TMDL?

  • No, that is incorrect. You will have to use the Numerical WLA found in Columns F & G to determine if you are meeting your WLA.

Please submit questions to Anna Bosch at the MPCA.

Examples

Related pages and useful links

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