Guidance for completing the TMDL reporting form

This site is currently undergoing revision. For more information, open this link.
This site is under construction. Anticipated completion date is early January, 2015.

This User Guide is intended to assist Municipal Separate Storm Sewer System (MS4) Permittees in the completion of the Commissioner-approved TMDL Annual Reporting Form (TMDL Form).

Purpose of the TMDL Annual Report form

Annual submission of the Total Maximum Daily Load (TMDL) Form is a requirement for Permittees that own or operate MS4s covered under the MS4 General Permit (Permit Number MNR040000) and have a Wasteload Allocation (WLA) approved by the United States Environmental Protection Agency (USEPA) prior to August 1, 2013. The TMDL Form creates a consistent format for MS4 Permittees to track structural BMPs (a stationary and permanent BMP that is designed, constructed, operated, and maintained to prevent or reduce the discharge of pollutants in stormwater) and non-structural BMPs (e.g. establish ordinance, education and outreach, illicit discharge elimination, etc.) designed to control stormwater discharges to surface waters with a WLA established in a USEPA-approved TMDL.

Information: Note that all WLAs applicable to a Permittee may not be included in their Annual Report Form. There are two scenarios in which this may occur:

• When the TMDL report explicitly states no reduction in pollutant loading is needed for an MS4 WLA, that WLA will not be included in the TMDL Annual Report Form.
• When the Permittee has stated they are meeting a WLA at the time of application, that WLA will not be included in the TMDLA Annual Report Form.

Submission of this form fulfills the permit requirement (Part III.E) to demonstrate continuing progress toward achieving WLAs . This is achieved by including information on one or more of the following in the TMDL Form.

• An inventory of structural and non-structural BMPs within the watershed tributary to the impaired water. To determine watershed boundaries see the specific TMDL report or request shapefiles (zip files provided at bottom of page) from the MPCA.
• An estimate of annual cumulative pollutant load reductions for certain structural BMPs.
• A summary of the number of BMPs or activities implemented and applied to an applicable WLA.
• A description of planned and in-progress BMPs and other pollutant management strategies that have not yet been implemented.

TMDL requirements in stormwater permits

NPDES permit langauge

Specific language that requires MS4 Permittees to submit progress towards meeting a WLA is contained in Part III.E of MPCA Permit No: MNR040000, effective August 1, 2013. Specifically,

E. Discharges to Impaired Waters with a USEPA-Approved TMDL that Includes an Applicable WLA.

For each applicable WLA approved prior to the effective date of this permit, the BMPs included in the compliance schedule at application constitute a discharge requirement for the Permittee. The Permittee shall demonstrate continuing progress toward meeting each discharge requirement, on a form provided by the Commissioner, by submitting the following:

1. An assessment of progress toward meeting each discharge requirement, including a list of all BMPs being applied to achieve each applicable WLA. For each structural stormwater BMP, the Permittee shall provide a unique identification (ID) number and geographic coordinate. If the listed structural stormwater BMP is also inventoried as required by Part III.C.2, the same ID number shall be used.
2. A list of all BMPs the Permittee submitted at the time of application in the SWPPP document compliance schedule(s) and the stage of implementation for each BMP, including any BMPs specifically identified for the small MS4 in the TMDL report that the Permittee plans to implements.
3. An up-dated estimate of the cumulative reductions in loading achieved for each pollutant of concern associated with each applicable WLA.
4. An up-dated narrative describing any adaptive management strategies used (including projected dates) for making progress toward achieving each applicable WLA.

SWPPP Development

All MS4 Permittees that manage a stormwater discharge to an impaired water with a TMDL approved by the USEPA prior to August 1, 2013, have incorporated information for each applicable WLA in their SWPPP documents, as required in Part II.D.6 of MPCA Permit No: MNR040000, effective August 1, 2013. Specifically, Permittees have developed the following information.

6. For each applicable Waste Load Allocation (WLA) approved prior to the effective date of this permit, the applicant shall submit the following information as part of the SWPPP document:

a. TMDL project name(s)

b. Numeric WLA(s), including units

c. Type of WLA (i.e., categorical or individual)

d. Pollutant(s) of concern

e. Applicable flow data specific to each applicable WLA

f. For each applicable WLA not met at the time of application, a compliance schedule is required. Compliance schedules can be developed to include multiple WLAs associated with a TMDL project and shall include:

(1) Interim milestones, expressed as BMPs or progress toward implementation of BMPs to be achieved during the term of this permit

(2) Dates for implementation of interim milestones

(3) Strategies for continued BMP implementation beyond the term of this permit

(4) Target dates for the applicable WLA(s) will be achieved

g. For each applicable WLA the Permittee is reasonable confident is being met at the time of application, the Permittee must provide the following documentation:

(1) Implemented BMPs used to meet each applicable WLA

(2) A narrative describing the Permittees strategy for long-term continuation of meeting each applicable WLA. This information was reported in the Excel form titled: MS4 Permit TMDL Attachment Spreadsheet (wq-strm4-49c). Interim milestones incorporated into the MS4 Permit TMDL Attachment Spreadsheet must be included in the TMDL Form.

Annual Reporting Schedules

Permittees with applicable WLAs shall submit the TMDL Form to the MPCA by June 30th of each calendar year, beginning in 2015. The TMDL Form must be submitted with the Annual Report, which is also due June 30 of each calendar year. Additional information regarding the MS4 General Permit schedule and the SWPPP Submittal Schedule can be found in Appendix A of the MS4 General Permit and on the MPCA’s MS4 Annual Report web page.

TMDL Annual Report form

Each Permittee will have a custom TMDL Form created by the MPCA that lists all WLAs affecting the Permittee (see information box under the Purpose of the TMDL Annual Report from section). The MPCA will not modify and resend the TMDL Form during the current permit cycle that is effective through July 31, 2018. The Permittee will therefore be responsible for maintaining the TMDL Form (the Permittee will add to the existing form each year of the permit term). The same spreadsheet will be updated by the Permittee throughout the permit cycle. The Permittee will submit the spreadsheet each annual reporting year, starting with the 2014 Annual Report. The MPCA will maintain copies of all submitted files.

Information: In the Annual Report Form, TMDL WLAs are expressed differently depending on the type of receiving water.

• Lake TMDLs: Will be labeled by Waterbody + Pollutant. The title of the TMDL Project will therefore not be captured.
• Stream TMDLs: For ease of reporting, the Permittee is allowed to report on groupings of WLAs within the same report. Stream TMDLs will therefore be labeled by TMDL Project Name + Pollutant. For example, if the Permittee has TSS WLAs on four stream reaches in a single project, these will be grouped into one TMDL to report on. If the Permittee has been assigned WLAs for bacteria (whether they are expressed as fecal coliform or E. Coli) on the same four stream reaches in the same project, the Permittee would have two TMDLs to report on. Note that a Permittee may request to have the form customized to allow for individual reach reporting, however, the grouping convention will be the default.

This guidance document provides information for MS4 Permittees to reference in completing the TMDL Form. The TMDL Form is an Excel spreadsheet that includes eight (8) color coded tabs (worksheets):

• Green tabs include worksheets in which the User will enter specific information. These tabs must be completed by the Permittee.
• Blue tabs are worksheets that track optional information for each User.
• Yellow tabs contain reference lists and values used to help populate the information in the green tabs or in the MPCA Simple Estimator. Information in these worksheets generally cannot be edited by the Permittee. A brief description of each worksheet is given below.

Spreadsheet user information (Blue Tab) is an optional worksheet that contains general information for the User. There is a section for MS4 Permittees to track dates that information was updated and that provides a link to this User Guide. The MPCA recommends that Permittees keep this sheet updated as a means of tracking entries into the TMDL Form.

BMPs-Activities completed (Green Tab) is a required worksheet. The User enters data related to specific BMPs or activities that were completed during the reporting period (January 1 - December 31 of the year prior to form due date) and that are applied to meeting an applicable WLA. BMPs/activities are associated with each applicable TMDL WLA.

Cumulative reductions (Green Tab) is a required worksheet. The User enters data regarding the estimated pollutant load reduction(s) resulting from implementation of BMPs/activities and information on BMPs/Activities being applied to applicable WLAs.

Adaptive management strategy (Green tab) is a required worksheet. The User provides a narrative describing any adaptive management strategies used for making progress toward achieving each applicable WLA.

List of TMDLs (Yellow Tab) is a reference worksheet, which contains a list of all the TMDLs in Minnesota with MS4 stormwater WLAs approved by the USEPA before the effective date of the MS4 General Permit, August 1, 2013. The MPCA is responsible for maintaining this information. The User cannot edit this information.

MPCA simple estimator (Blue Tab) is an optional User input tab that allows the User to estimate the cumulative reduction (mass or percent removal) of a pollutant of concern achieved by implementation of BMPs. The reductions calculated here can be used when entering information into the quantitative reductions portion of the Cumulative reductions tab (Guidance and examples for using the MPCA Simple Estimator).

Input values for the MPCA estimator (Yellow Tab) contains the information used in the MPCA simple estimator worksheet. Information here is based on literature reviews and therefore general in nature and may not accurately reflect the User site conditions. Therefore, the User is encouraged, as much as is possible, to use their own site data to fill in the cells in the MPCA simple estimator worksheet. The MPCA is responsible for maintaining this tab.

Dropdown lists (Yellow Tab) contains a list of the inputs for the dropdown lists found in the BMPs-Activities completed and Cumulative reductions worksheets. The MPCA is responsible for maintaining this tab. The User cannot edit this information.

Screen shot of the TMDL Annual Report Form User information tab.

Spreadsheet User information tab

The tab titled Spreadsheet user information contains an optional worksheet that can be used to track the most current version of the form. There are two boxes contained in this worksheet.

• Form Information describes the TMDL Form and tracks the dates when the form was created by the MPCA. Cells containing the Permittee name and Permit ID are locked and cannot be edited.
• User Information allows MS4 Permittees to track dates pertaining to submission of the TMDL Form. Users should note that the MPCA will fill in the Permittee Name and Permit ID but the Permittee can indicate the most recent update in this part of the TMDL Form. These cells will be locked and should not be changed by the MS4 Permittee.

BMPs-activities completed tab

The worksheet tab called BMP-Activities completed is used to record compliance with the requirement to demonstrate continuing progress towards meeting applicable WLAs.

Information: The Permittee is not required to report on every BMP/Activity they implement, but instead just on BMP/Activities they are applying toward applicable WLAs.

The content of this worksheet is shown in the two figures below. Grey cells are filled out by the MPCA and cannot be edited by the Permittee. White cells are MS4 User input cells. Brown cells are optional MS4 User input cells but are highly encouraged. Note that some of these white cells are optional or may be auto-filled depending on inputs in other white cells. Information required in this worksheet includes:

• Reporting year,
• BMP/Activity,
• BMP/activity owner, and
• TMDL WLA(s) to which the BMP/activity is being applied.

If the BMP chosen in Column E of the tab is a constructed basin, filter, infiltrator, or swale or strip, the User is required to enter, in columns H through K,

• BMP ID,
• y-coordinate,
• x-coordinate, and
• Coordinate system (e.g. lat-long, UTM).

If another BMP is entered in Column E, cells in Columns H through K will auto fill with “NA”. Optional information includes the year that the BMP was implemented and any additional notes. Detailed guidance on each of these columns can be found below.

Detailed guidance for completing the BMP-activities completed tab

Screen shot of the BMP-Activities completed tab, Columns A through M, of the TMDL spreadsheet.

Screen shot of the BMP-Activities completed tab, Columns N and beyond, of the TMDL spreadsheet.

Column A – Entry ID

• Description: BMP line number. MPCA uses this ID for compiling data from all Permittees into a single database. The worksheet allows up to 1000 entries.
• Input: None
• Source of Information: The MPCA inputs this data.

Column B – Permittee

• Description: Name of the TMDL Permittee
• Input: None
• Source of Information: This cell autofills when a value is entered for reporting year (Column D)

Column C – MS4 ID

• Description: The MS4 ID number assigned to the Permittee by the MPCA
• Input: None
• Source of Information: This cell autofills when a value is entered for reporting year (Column D)

Column D – Reporting year

• Description: The reporting year in which the BMP or activity was implemented
• Input: Reporting year
• Source of Information: User

Information: Note that the Permittee is reporting only BMPs/activities implemented during the previous calendar year (January 1 through December 31) and should not take credit for something done in a different reporting year. If this is the first year using this form, BMPs should be entered for the previous calendar year and all prior years back to the baseline year. The baseline year can be found in Column E of the Cumulative reductions tab.

Column E – BMP/Activity

• Description: The type of BMP used or activity conducted
• Input: Dropdown
• Source of Information: Column E from the Dropdown lists tab. The User selects the appropriate BMP from a dropdown menu contained in the cell. Users must include all BMPs that were reported in the MS4 Permit TMDL Attachment Spreadsheet that was submitted at the time of permit application. If a particular BMP/activity you implemented is not listed, open the Excel spreadsheet File:Cross-Reference list.xlsx to determine the appropriate selection from the dropdown list. If the BMP/activity is not listed in the reference list, use Best Professional Judgment or contact the MPCA.

Information: The BMP/Activities contained in the drop-down list is a short-list containing categories of BMPs. Users who are interested in referencing a more specific BMP name should enter that information in Column F or Column Q.

Column F – BMP Description (Optional)

• Description: Specific BMP/Activity description.
• Input: BMP or Activity name
• Source of Information: Dropdown list or User

Column G – Location and ID Information Needed?

• Description: A description of whether an ID and location information is needed for the BMP
• Input: None
• Source of Information: This cell autofills depending on the input for Column E. For structural BMPs (constructed basins, filter, infiltrator, swale or strip) this cell autofills with the statement "Complete columns H through K" and the User is required to fill in Columns H through K. If any other BMP is entered in Column E in this row, the cell autofills with the statement "No ID information needed" and the User is not required to fill in Columns H though K in this row.

Column H – BMP ID

• Description: ID Number assigned to the BMP by the Permittee or Owner
• Input: ID Number. The User will input data only if the BMP is a structural BMP (constructed basin, filter, infiltrator, swale or strip). If it is not, then the cell will auto fill with NA. If the BMP was included in the Permit TMDL Attachment Spreadsheet, the ID Number must match the ID in the Permit TMDL Attachment Spreadsheet.
• Source of Information: User and MS4 Permit TMDL Attachment Spreadsheet. Note that you may have a database with ID numbers for BMPs. It is recommended that you use the ID from your database for this field.

Columns I & J – Geographic Coordinates

• Description: Geographic coordinates for structural BMPs (constructed basin, filter, infiltrator, swale or strip)
• Input: x- and y-coordinates. The User will input data only if the BMP is structural. If it is not then the cell will auto fill with NA. These coordinates must match the coordinates of individual BMPs in the MS4’s Permit TMDL Attachment Spreadsheet that were identified by a geographic coordinate. For constructed stormwater ponds, x, y coordinates should match those submitted with the MS4 Pond, Wetland, and Lake Inventory Form. That form is due within 12 months of permit coverage.
• Source of Information: User and MS4 Permit TMDL Attachment Spreadsheet

Information: Note that you may have a database with geographic coordinates for BMPs. It is recommended you use the coordinates from your database for this field. If you have not determined coordinates for a BMP, it is recommended that BMP coordinates represent the centroid of the BMP. If you have BMPs mapped as polygons, it is recommended you provide x,y coordinates at the approximate center of the polygon.

Information: HOW DO I DETERMINE THE COORDINATES OF MY BMP IF I DON'T HAVE THEM? If you do not use a Global Positioning System (GPS) or mapping software, such as ArcMap, there are numerous tools on the Internet to determine location information. Examples include [1], [2], [3], as well as Google Earth.

Column K – Coordinate System

• Description: The coordinate system used when measuring the x- and y-coordinates of the structural/quantifiable BMP
• Input: Dropdown with an option for the User to enter a different value. The User will input data only if the BMP is structural (constructed basin, filter, infiltrator, swale or strip). If it is not then the cell will auto fill with NA.
• Source of Information: User and MS4 Permit TMDL Attachment Spreadsheet

Column L – Who Owns this BMP/Activity?

• Description: Users will have three options to select from: Permittee, Other MS4 Permittee, or Other. The purpose of this data is to allow multiple Permittees to take credit for the same BMP/activity while providing MPCA a mechanism for avoiding double counting of a single BMP. Ownership is important to report for those situations where the Permittee and owner are the same. For example, a Permittee may take credit for a BMP/activity that was installed/implemented as a part of a development project or collaborative project with a neighboring MS4 or other entity and to which the Permittee contributed (e.g. partially funded a project, allowed the BMP/activity to be partly/fully implemented in their MS4, provided technical support to implementation of a BMP/activity, etc.). For this circumstance the User should select Other MS4 Permittee. The permittee may also take credit for a privately owned BMP that was installed on a development/redevelopment site that drains to the Permittee’s storm sewer system. For this circumstance the User should select Other.
• Input: Dropdown
• Source of Information: User

Column M – If applicable name other owner(s)

• Description: Name of MS4 permittee that owns or co-owns a BMP that the Permittee opts to report as serving to control the volume or pollutant load associated with a WLA. For example, if you contributed funding to a BMP that is owned and operated by another permittee, you may include this BMP in this form but indicate who the owner is in this column.
• Input: Column M will autofill with NA (not applicable) when the user selects “Permittee” or “Other” from the dropdown list of Column L. User should fill in the name of the BMP owner for only those BMPs that are owned, or co-owned by another MS4 permittee.
• Source of Information: User

Column N - Will you record this BMP in Category 1 or Category 2? (Optional)(See Cumulative Reductions tab)

• Description: This is an optional field used to identify BMPs that are being used for credit by more than one permittee. BMPs are incorporated into the TMDL Form either as Category 1 or Category 2 BMPs. Category 1 is used when reductions in pollutant loading by BMPs can be quantified and the BMP occurs within the jurisdiction of the permittee. BMPs that can be quantified include infiltration BMPs such as infiltration basins, filtration BMPs such as bioretention and sand filters, constructed basins, and swales and filters. Other BMPs may be included in Category 1 if the permittee can provide information to support quantifying load reductions from the BMP.
• Input: Dropdown menu with choices being Category 1 and Category 2.
• Source of Information: User

Column O - Will another permittee take Category 1 Credit? (Optional)

• Description: This is an optional field used to determine if another permittee is taking Category 1 credit for a BMP. The purpose is to help get a more accurate estimate of the total pollutant load decrease resulting from implementation of BMPs.
• Input: If the answer to Column N is Category 1, this column autofills with NA.
• Source of Information: User

Column P – Date when BMP was implemented (Optional)

• Description: The date in which the BMP/activity was implemented. This refers to the date when the BMP became operational.
• Input: Date
• Source of Information: User

Column Q – Note(s) (Optional)

• Description: Any additional information that the User would like to enter into the spreadsheet to track progress, provide additional detail, etc. This is an optional input. Examples are shown in the Example TMDL Form.
• Input: Notes
• Source of Information: User

Columns S and beyond – TMDL Project with TMDL WLAs

• Description: Each column will contain a TMDL Project with one or more applicable WLAs for the MS4. The actual number of columns for each MS4 form will be unique to the number of USEPA-approved TMDLs and WLAs within the MS4 Permittee’s jurisdiction. The MPCA will insert the column headings specific to each MS4 Permittee. The listed projects may include multiple WLAs for the same receiving water and pollutant. For example, a TMDL report may include WLAs for different flow regimes and different stretches of the same river. These have been combined when appropriate to simplify the reporting process.

Permittees may wish to report individually on all receiving water bodies within its jurisdiction. For example, the City of Worthington has 8 separate river or stream stretches that have approved WLAs for TSS and are part of the West Fork of the Des Moines River TMDL project. The spreadsheet for Worthington will only list one TMDL Project for TSS – the West Fork Des Moines River Watershed Nutrient TMDL – TSS. The 8 separate river stretches are thus combined into a single project on which to report. The City of Worthington may wish to report on the 8 stretches individually.

• Input: ‘X’ to designate a TMDL for which a unique BMP/activity is being applied.
• Source of Information: User

Cumulative reductions tab

Screen shot of the Cumulative reductions tab from the TMDL Annual Report Form.

The worksheet or tab called Cumulative reductions is used to track the total annual cumulative progress towards reduction of pollutants discharged to an impaired water with a USEPA approved TMDL. Cumulative progress may be reported in terms of measured or calculated pollutant reductions, number of BMPs implemented, and BMPs that have not been fully implemented at the time of this report. Completion of this worksheet fulfills compliance with Section III.E.3 of the MS4 General Permit (Permit Number MNR040000).

The contents of this worksheet are shown in the figure to the right. As with the BMPs-Activities completed tab, cells that are grey are column/row headings and cells that the MPCA will fill out for each MS4. Cells that are white are User input cells.

Information: The information in this worksheet is summary in nature. MS4 permittees are advised to maintain a record of the data used to complete this form, including information such as BMP name, total annual pollutant load reduction, technique used to compute pollutant load reduction, date the BMP went into operation (for partial year computations), and other information that may assist the MS4 Permittee. Some of this information may be included in the BMPs-Activities completed tab.

Three categories of reporting are described in detail below. The choice of category for reporting is dependent on whether the BMPs/activities can be quantified for the pollutant of concern and whether the BMPs/activities have been fully implemented. Recommendations for the choice of Category are provided below. For Category 1 and Category 2, it is assumed the BMP/activity was in operation during the previous year, or if this is your first reporting year, between the baseline year and the past year. The baseline year is provided in Column E of the Cumulative reductions tab

• Use Category 1 if all of the following apply.
  • Pollutant loadings from the BMP/activity can be quantified using an appropriate method
  • The pollutant is phosphorus, TSS, fecal coliform, or E. coli
  • The BMP/activity was constructed within your jurisdiction (within your MS4)
• Recommend using Category 2 if the following applies, but Category 1 may be used if you have detailed records
  • The pollutant is chloride
• Use Category 2 if any of the following applies.
  • Pollutant is Biochemical Oxygen Demand (BOD), Nitrogenous Biochemical Oxygen Demand (NBOD), chloride, or thermal loading
  • Pollutant reductions from the BMP/activity cannot be quantified using an appropriate method
  • You contribute(d) to the implementation of the BMP/activity but the reduction in pollutant loading occurs outside your jurisdictional area (e.g. you contributed funding to a BMP in a different MS4)
• Use Category 3 if the BMP was not in operation during the past year. If the BMP was in operation for part of the year, you may wish to prorate the load reduction and enter that value in Category 1.

Overview of categories

Category 1 - Summary of quantitative reductions The purpose of this category is to quantify pollutant loads from the permittee's MS4. This category should be used when reductions in pollutant loading by BMPs occur within a permittee's jurisdiction and can be quantified using an appropriate method for one of the following pollutants.

• Total phosphorus
• Total suspended solids
• E. coli
• Fecal coliform
• Chloride – NOTE: The MPCA recommends that Permittees with chloride WLAs choose Category 2 for reporting.

Warning: Permittees should report cumulative reduction from their MS4, even if some of the pollutant loading to their system comes from an adjacent regulated MS4. For example, if you have a BMP that treats runoff from 5 acres within your jurisdiction and runoff from 5 acres outside your jurisdiction, you should report the total reduction in pollutant load rather than just the load from the 5 acres within your jurisdiction.

The following options exist for reporting load or load reduction.

• pounds or number (for bacteria) reduced
• kilograms or number (for bacteria) reduced
• percent load reduction
• pounds or number (for bacteria) per acre reduced
• kilograms or number (for bacteria) per hectare reduced
• load (pounds or number of bacteria)
• load (kilograms or number of bacteria)

Information: Reductions from all BMPs/activities included in this category are reported as a single cumulative number. For example, if 5 rain gardens (bioretention systems) were in operation and each rain garden reduced phosphorus loading by 10 pounds per year, and no other BMPs can be quantified, then the Permittee would report a cumulative reduction of 50 pounds of phosphorus.

The following BMP/activities should be quantified:

• Infiltrator: examples include infiltration trench, infiltration basin, tree trench/box, permeable pavement, infiltration vault, bioinfiltration
• Constructed basin: examples include wet pond, stormwater wetland, dry pond
• Filter: examples include sand filter, green roof, biofiltration, iron enhanced sand filter
• Swale or strip: examples include filter strip, swale, wet swale, grass waterway

These BMPs are included or can be simulated in most water quality models and calculators used for estimating stormwater loading. The Minnesota Stormwater Manual also provides typical reduction efficiencies for these BMPs. Note that you may have information that allows for quantifying pollutant reductions for BMPs other than those listed above, or you may have different pollutant removal values based on local data. For example, many water quality models and calculators will calculate pollutant reductions associated with street sweeping.

The following BMPs may be quantifiable. The Stormwater Manual either provides limited or no pollutant removal efficiencies or guidance for these BMPs, however.

• Manufactured Device: examples include drain inlet insert, geocells, grit chamber, gross pollutant trap, hood, hydrodynamic separator, manufactured filter, oil/grit separator, pollutant trap, SAFL Baffle, SAFL Baffle sump manhole, sump, sump manhole, swirl separator, water quality inlet
• Street sweeping if records are kept for material added to roads (e.g. sand) and removed through sweeping. See Street sweeping for trees.
• Removal of an illicit discharge if the volume of discharge and pollutant concentration are known
• Stormwater capture and reuse if the volume of runoff captured and pollutant concentrations are known. See Stormwater re-use and rainwater harvesting
• Improved lawn, turf, vegetation, soil practices if the practice results in decreased pollutant application (e.g. fertilizer) or increased infiltration (e.g. improved soil or turf). See Turf.
• Chemical treatment of stormwater: if the volume, pollutant concentrations, and removal efficiency are know, or if monitoring is conducted. See Iron enhanced sand filter (Minnesota Filter)

Information: The MPCA encourages the use of local data in determining BMPs that can be quantified and in establishing a pollutant removal value for a specific BMP.

Category 2. Qualitative information on number of BMPs implemented The purpose of this category is to identify and acknowledge BMPs/activities that likely reduce pollutant loads but that are either difficult to quantify or that reduce pollutant loads outside the permittee's MS4.This category should be used to track those BMPs or activities that operate in one or more of the following conditions.

• BMPs or activities for which pollutant load reductions cannot be quantified. These include non-structural BMPs such as education and structural BMPs for which pollutant removal values are not in the Stormwater Manual (e.g. hydrodynamic devices).
• Structural BMPs and non-structural BMPs within watersheds tributary to impaired waters that have a WLA for Biochemical Oxygen Demand (BOD), Nitrogenous BOD (NBOD), thermal loading, or chloride. Removal efficiencies for these pollutants are generally lacking in the literature.
• The permittee contributed to the BMP or activity (e.g. contributed funding) but reductions in pollutant loading from the BMP/activity occur outside the jurisdictional area of the permittee. These BMPs cannot be included in Category 1 because they do not decrease the load leaving the permittee's MS4.

As with Category 1, the value entered represents a cumulative value, in this case the total number of BMPs/activities that are applied to a TMDL Project. All BMPs and activities included in this number must be included in the BMPs-Activities completed tab.

Category 3. Non-implemented Activities This is a section the MS4 Permittee may use to report on planned BMPs that have not yet been implemented but that are important components of future achievement of WLAs. BMPs that have been described in the MS4 SWPPP, but have not yet been implemented can be tracked in Category 3. Both structural and non-structural activities may be included in this section of the worksheet.

Detailed guidance for the Cumulative reductions tab - Category 1

Columns A and B – MS4 Information

• Description: MS4 Permittee Name and MS4 ID
• Input: None
• Source of Information: The MPCA will input this information.

Column C – TMDL project

• Description: The name of the TMDL project. A TMDL project may include multiple TMDL WLAs and multiple receiving waters that have been combined for ease of reporting. A TMDL project has only one pollutant. The project name(s) match(es) the names listed starting in Column S of the BMPs-Activities completed tab.
• Input: Column D or Column C from the List of TMDLs tab. The project name(s) match(es) the names listed starting in Column S of the BMPs-Activities completed tab.
• Source of Information: The MPCA will input this information.

Column D – Units

• Description: The units of measurement for the pollutant reduction (e.g. pounds, kilograms, %) for each TMDL project
• Input: Dropdown with an option for the User to enter a different value
• Source of Information: User

Column E – Baseline Year

• Description: The year that established the Baseline for the WLA
• Input: TMDL Baseline Year
• Source of Information: The MPCA will input this information.

Columns F through L – Years

• Description: Annual pollutant load reduction for the total of all BMPs within the specific TMDL watershed. If the User is reporting on more than one BMP within one TMDL watershed, the reductions should be totaled and presented as one value for that year. For subsequent years, include reductions from all BMPs, including BMPs included in the previous year’s reporting. For example, if 5 rain gardens (bioretention) achieved 50 pounds reduction in 2014 and 5 newly built rain gardens achieved 40 pounds reduction in 2015, the total reduction is 90 pounds, assuming all rain gardens have been maintained and are still performing as designed. Similarly, if a BMP is removed or no longer functioning properly, it should not be included in estimates of total reduction. The Permittee is thus reporting on cumulative reductions over a period of several years when several BMPs or activities may be implemented.
• Input: Calculated or measured pollutant reduction (e.g. pounds, kilograms, %, etc.).
• Source of Information: User

Column M – Calculation Method (Optional)

• Description: The Permit allows MS4 permittees to demonstrate progress towards meeting WLA goals either through direct monitoring or a computational method using models or calculators. This optional column allows the user to track the method used to compute the WLA reduction for the purpose of recording and/or tracking or noting changes from year to year.
• Input: Description of monitoring, if obtained. Name of model or calculator, if utilized.
• Source of Information: User

Column N – Notes (Optional)

• Description: Users may describe background information, computational details or other data that could further explain the progress towards meeting the WLA.
• Input: User defined.
• Source of Information: User

Detailed guidance for the Cumulative reductions tab - Category 2

These are BMPs or activities that have been implemented but are not quantified in terms of pollutant reduction.

Columns A and B – MS4 Information

• Description: MS4 Permittee Name and ID
• Input: None
• Source of Information: The MPCA will input this information.

Columns C and D– TMDL project

• Description: The name of the TMDL project. A TMDL project may include multiple TMDL WLAs and multiple receiving waters that have been combined for ease of reporting. A TMDL project has only one pollutant.
• Input: Column C or D from the List of TMDLs tab
• Source of Information: The MPCA will input this information.

Column E – Baseline Year

• Description: The year that established the Baseline for the WLA
• Input: TMDL Baseline Year
• Source of Information: The MPCA will input this information.

Columns F through L – Years

• Description: The number of BMPs not included in Category 1 that were implemented in the reporting year. This includes BMPs or activities operated in previous years, assuming the BMP or activity is still implemented and achieving pollutant reductions. For example:
  • If the User was working under a particular TMDL in 2014 and conducted employee training related to a structural BMP, a “1” would be entered into cell C14, meaning that one BMP/activity was implemented and that activity was not quantified in Category 1.
  • If the User also enacted an ordinance relating to the reduction of phosphorus, then a “2” should be entered into cell C14, meaning that two BMPs/activities were implemented and that neither activity was quantified in Category 1.
  • If there also is an Infiltration Trench within the watershed of the impaired water, then a “2” should be entered into C14, meaning that the two BMPs/activities above (employee training and ordinance) are not quantified, but the infiltration trench is quantified (it is an Infiltrator BMP). In this case, the Permittee would also have a value entered in Category 1 for this TMDL project since the infiltration trench is quantified.
  • If the employee training and ordinance cited above are still achieving reductions in 2015, and the Permittee implements another education program, then the Permittee would enter a “3” in the 2015 reporting year.
• Input: Number of BMPs in operation during reporting year
• Source of Information: User

Columns M and N – Notes (Optional)

• Description: Users may describe background information, computational details or other data that could further explain the progress towards meeting the WLA.
• Input: User defined.
• Source of Information: User

Detailed guidance for the Cumulative reductions tab - Category 3, Number of BMPs

Columns A and B – MS4 Information

• Description: MS4 Permittee Name and ID
• Input: None
• Source of Information: The MPCA will input this information.

Columns C and D – TMDL project

• Description: The name of the TMDL project. A TMDL project may include multiple TMDL WLAs and multiple receiving waters that have been combined for ease of reporting. A TMDL project has only one pollutant.
• Input: Column C or D from the List of TMDLs tab
• Source of Information: The MPCA will input this information.

Column E – Baseline Year

• Description: The year that established the Baseline for the WLA
• Input: TMDL Baseline Year
• Source of Information: The MPCA will input this information.

Columns F through L – Years

• Description: BMP and activities that have been started but are not yet implemented. These BMPs and activities must be listed in this grouping. Over time these BMPs or activities will be completed and then moved into Category 1 or Category 2. This number may therefore decrease from one year to the next.
• Input: Total count of BMPs to be implemented
• Source of Information: User

Columns M and N – Notes (Optional)

• Description: Users may describe background information, computational details or other data that could further explain the progress towards meeting the WLA.
• Input: User defined.
• Source of Information: User

Detailed guidance for the Cumulative reductions tab - Category 3, BMP and activity inventory

These are BMPs or activities that have not yet been implemented but are in some stage of development and that when implemented will result in pollutant load reductions.

Columns A and B – MS4 Information

• Description: MS4 Permittee Name and ID
• Input: None
• Source of Information: The MPCA will input this information.

Column C and D – BMP Description

• Description: Description of planned BMP or activity, such as “Stormwater Pond located at the intersection of Main Street and Central Ave”.
• Input: BMP
• Source of Information: User

Column E – Status

• Description: Status of planned BMP
• Input: Planned, funded, under construction, or other user-specified status
• Source of Information: Dropdown box

Column F – Reporting Year

• Description: Year the BMP is to be constructed or implemented
• Input: Year
• Source of Information: Dropdown box

Estimation of pollutant load reduction for the Cumulative reductions tab

The TMDL Form requires Permittees to quantify pollutant reductions for BMPs/activities that have established pollutant removal values for phosphorus, TSS, fecal coliform bacteria, or E. coli bacteria. “Established pollutant removal value” means the Stormwater Manual provides values for pollutant removal or MPCA has included a pollutant removal value in the Input values for MPCA estimator tab of the TMDL Form.

In addition to the values provided in the TMDL Form, MS4 Permittees have multiple options for determining the pollutant load reduction of a specific BMP. The Permittee may opt to use any of these techniques. As described above, Permittees are encouraged to record the methodology utilized for computing pollutant load reductions in order to manage the data and changes that can occur each reporting year.

Models and calculators

The Minnesota Stormwater Manual contains an up-to-date list of models and calculators that can be used to compute the pollutant removal of a specific BMP. The models range from complex software that calculate hydrology/hydraulics/water quality such as USEPA SWMM, to User friendly calculators such as the MIDS calculator. Permittees are advised to consider the following.

• Stand-alone water quality models, such as P8, work well for situations that do not require a hydraulic analysis.
• Complex models such as SWMM work well for watersheds with multiple BMPs, but may require a MS4 Permittee to hire a modeling expert or consultant.
• Most water quality models will compute reductions in Total Phosphorus and Total Suspended Solids. A few models will assess additional pollutants.
• The model/calculator list of BMPs should be reviewed before selecting a model to utilize. For example, load reductions from a green roof can be computed using the MIDS Calculator, but is not in the list for P8. Some models, including P8, do have the capability of computing the load reduction from a User-defined BMP.

Credits

The Minnesota Stormwater Manual sections on Stormwater Management Credits offer four options to calcuate the pollutant removal for a number of BMPs. The term Credit implies pollutant loading and volume reductions. BMPs that have Credit sections include:

• Permeable Pavements
• Bioretention
• Infiltration trenches and basins
• Filters
• Swales
• Green roofs
• Tree trenches/boxes
• Constructed ponds and constructed wetlands

Four calculation methods are described in detail in each of these BMP Credit sections.

• Credits Based on Volume Reduction and BMP Parameters. Details hand calculation methods to compute volume reduction, Total Phosphorus, and Total Suspended Solids removal for a single BMP.
• Credits Based on Models. Provides detail on model selection. Also includes information on using the Minimal Impact Design Standards (MIDS) calculator.
• Credits Based on Literature. MS4 Permittees may opt to apply percentage removal values based on published literature values. Users of this technique are advised to use only values from peer-reviewed literature of BMPs that closely resemble the MS4 Permittee’s BMP. Values included in the TMDL Form are based on literature review.
• Credits Based on Field Measurement. MS4 Permittees and BMP owners may determine that the most accurate method of computing pollutant reduction is through direct monitoring of the BMP.

MPCA Simple Estimator

Included in the TMDL Form is a simple worksheet that has been created for the purpose of estimating pollutant load reductions using published reductions in Event Mean Concentration (EMC). Use of this worksheet is optional. This estimator is intended solely for computing load reductions for this Form, only, and is not intended to report on the exact performance of an individual BMP.

Adaptive Management Strategy tab

Screen shot of the Adaptive management tab in the TMDL worksheet. Click on image to enlarge.

The NPDES MS4 permit requires permittees to provide “(a)n up-dated narrative describing any adaptive management strategies used (including projected dates) for making progress toward achieving each applicable WLA”. This tab contains a text box for users to submit this narrative.

Example of an adaptive management strategy entered into the TMDL spreadsheet. Click on image to enlarge.

Adaptive management (AM) is a formal process for continually improving management policies and practices by learning from their outcomes. This portion of the annual report should describe the permittee's plan for continuing to demonstrate progress toward achieving applicable WLAs through development and implementation of structural and non-structural BMPs. It could be an explanation of how the MS4 permittee intends to carry out the remaining interim milestones (BMPs) in their compliance schedule (e.g., project funding details, details of a feasibility study, efforts to establish partnerships, updates on construction of a structural BMP, etc.). A narrative of continued compliance beyond the current permit term is also encouraged. The permittee can describe successes or shortcomings of a particular BMP and what was learned from the experience. This is also the portion of the annual report that would describe any changes to the compliance schedule the permittee wishes to pursue based on past observations and recognized program enhancement opportunities.

Information: The State of Wisconsin has created a detailed Adaptive Management Technical Handbook for Wisconsin TMDL compliance. Users may find additional information or concepts they wish to adapt in this reference. However, care must be taken when consulting with this or any non-Minnesota document that has not been explicitly endorsed by the MPCA.

For WLAs that have been met, permittees should use this tab to report on measures implemented that ensure continued compliance with WLA goals.

Detailed guidance for the Adaptive Management Strategy tab

• Description: Users are to annually provide a narrative describing any adaptive management strategies used (including projected dates) for making progress toward achieving each applicable WLA.
• Input: Year and text
• Source of Information: User.

Reference tabs

Several of the tabs within the TMDL Report Form are reference tabs. These tabs are described in more detail below.

List of TMDLs

Screen shot of the List of TMDLs tab.

• Description: A list of the EPA-approved TMDLs for Minnesota. Each TMDL is classified by waterbody, pollutant, and Permittee.
• Input: None
• Source of Information: MPCA
• Discussion: This worksheet provides information for approved TMDLs that have a WLA for regulated MS4 stormwater. The worksheet shows all impaired waters with stormwater WLAs, but not all WLAs are included. For example, for stream reaches with different WLAs for different flow regimes, only the mid-range WLA is included.

The MPCA uses this information to track information on MS4 WLAs and will use the data to track progress toward meeting TMDLs. For streams and rivers, Column D, TMDL + pollutant, is typically used in the BMPs-Activities completed and Cumulative reductions tabs for reporting. A Permittee may use the information in Column C for reporting if they prefer to report on individual receiving waters for which they have WLAs. For example, the City of Rochester has 17 WLAs listed in the List of TMDLs. However, they are only required to report on two TMDL projects – the Lower Mississippi River Basin Fecal Coliform Bacteria TMDL - Fecal Coliform and the Zumbro River Watershed TMDL for Turbidity Impairments – TSS projects. If the City wanted to report on all 17 impaired reaches, they would use the information in Column C and insert this into cells P3 through AF3 in the BMPs-Activities completed tab. If more than one lake is included in a cell in the column TMDL + pollutant, then Column C is used in the BMPs-Activities completed and Cumulative reductions tabs for reporting. This is to ensure that reporting is done for each lake.

Input values for MPCA estimator

Screen shot of the Estimator inputs tab.

This tab contains three types of information. The first is the fraction of pollutant removed from the stormwater runoff due to the presence of a BMP. The values apply to stormwater runoff that does not infiltrate into underlying soil. For water that infiltrates into the underlying soil, the pollutant removal is 100 percent. Any remaining runoff will bypass the system and cannot be considered for pollutant removal. Therefore the removal fraction for these BMPs is 0 because it only applies to the water that is not infiltrating into underlying soil. The pollutant removal fraction for infiltrated water equals the fraction of water that infiltrates. These values are included in cells C37, C58, C79, and C100 in the MPCA simple estimator tab. The default value for fraction that infiltrates is 0.90, which corresponds approximately with a BMP designed to capture a 1 inch rain event. All removal fractions are based on the assumption that BMPs were properly designed, constructed and maintained. See specifications and guidance for design, construction and maintenance of individual BMPs in the Minnesota Stormwater Manual. Removal fractions are consistent with values presented in the Stormwater Manual and the Minimal Impact Design Standards calculator.

The second type of information is the event mean concentration (EMC) of total phosphorus, TSS, E. coli, and fecal coliform in stormwater runoff in the various land use areas. The 2011 National Stormwater Quality Database is the primary source of this information. Cells in the worksheet are populated with mean or median values from the Upper Midwest (Zone 1), but the User may enter a different value if they have reliable data.

The third type of information is the runoff coefficient (Rv) for the various land use types. The input values are based on literature. The default is set at the median of values from the literature. The User may enter a value if available data supports the value. For a discussion of runoff coefficients, see [4].

Dropdown lists

• Description: The various options for the different dropdown lists used in the BMPs-Activities completed tab and Cumulative reductions tab.
• Input: None
• Source of Information: MPCA

Other resources, information and guidance for the TMDL spreadsheet

Cross-reference list of BMPs

• Description: For the purpose of this TMDL reporting spreadsheet, the MPCA has opted to develop a naming convention that organizes BMPs into common categories. The BMP naming convention is set in the drop-down lists for this form. The cross-reference list is an Excel spreadsheet, separate from the TMDL form, for Users that have a different BMP naming convention than that used in this form.
• Discussion: To ensure a TMDL Form that was functional, it was necessary to limit the list of BMPs to a manageable number. A particular BMP may have several names or variants. For example, bioretention BMPs are often called rain gardens or rain water gardens. Permeable pavement has several variants, including porous asphalt, porous concrete, and permeable interlocking concrete pavers (PICP).

The cross-reference spreadsheet contains an extensive list of terms for BMPs and identifies the BMP to select from the BMP dropdown list in Column E of the BMPs-Activities completed worksheet. The information is sorted by BMPs in the dropdown list (Column A). Column B contains different names and variants of a BMP. Find your BMP in Column B and select the corresponding name in Column A when selecting a BMP from the dropdown list in Column E of the BMP-activities completed worksheet. If you cannot find your BMP, do a word or term search using the Find command on the Home toolbar in Excel. If your BMP term is not listed, use Best Professional Judgment to select the appropriate BMP from the dropdown.

• Input: None
• Source of information: MPCA

The cross-reference list is included in a separate Excel spreadsheet rather than the TMDL spreadsheet because the MPCA realizes the BMP list is likely to grow over time. The cross-reference file is updated as needed.