MPCA discussion on draft permit

[lisa_admin]

MCSC recently met with MPCA staff to discuss the proposed changes to the MS4 Permit. Our conversation focused on non-stormwater discharges revisions, the addition of PFAS requirements, TMDL reporting requirements, and the proposed water quality trading program. I’ve included a summary of our discussion below.

If you have any questions on the proposed permit or would like to discuss revisions you’d like to see in the permit, feel free to contact Cole Landgraf at the MPCA, cole.landgraf@state.mn.us, he’s the permit writer for this permit.

MCSC is preparing written comments to submit to MPCA on the draft permit and will send those out to membership prior to the comment due date so that cities can build on those comments.

Non-Stormwater Discharge – section 3.2 and 28.16
• Why has the word “emergency” been added for firefighting activity?
Summary of MPCA Response:
The differentiation of emergency firefighting activity from other firefighting activities is common in MS4 permits across the country. It will allow cities to consider BMPs to address runoff from firefighting activity in non-emergency situations such as those where there is not an imminent threat to life safety.
MCSC Input:
Many MS4s have limited authority over the firefighting response team in their city and many are reluctant to assert requirements on emergency personnel.

Non-Stormwater Discharge – section 3.3
• Why has the MPCA added this section?
• What is the reasoning and expected use for the list of factors to consider?
Summary of MPCA Response:
This section was added to address a unique situation where a permittee discharged a large quantity of potable water that resulted in an impact on aquatic life in the receiving water due to temperature and disinfectants creating conditions toxic for aquatic life. Outside organizations pushed for this addition to the permit.
MPCA wants to see that MS4s are thinking through actions that could impact receiving waters if the quantity of a non-stormwater discharge combined with other properties such the presence chlorine/chloramine could have a negative impact. Section 3.3 is intended to work in conjunction with section 3.2 such that MS4 permittees will consider the list of authorized non-stormwater discharges and other non-stormwater discharges (such as draining a water tower or a municipal swimming pool) and evaluate if those discharges could result in an impact to the receiving water.
MCSC Input:
MCSC will develop suggested language in its written response to this request for informal comment. MCSC also suggested that cities could address this requirement by directing inquiries related to approval of non-municipal non-stormwater discharges through the MPCA’s stormwater permitting process.

PFAS – 18.15 & 21.13-21.15
• Why has MPCA included PFAS standards in the current draft MS4 permit?
• Including the provisions in 21.13-21.15 in the MS4 permit appears to create one set of pesticide rules for MS4 cities and another set of rules for everywhere else in the state. Is this the MPCA’s goal? Is this fair or workable?
Summary of MPCA Response:
MPCA has put PFAS as an agency and state priority and considered the sources that were within permittee control: firefighting foams and pesticides. Section 18.15 is already state law and was added for visibility. Sections 21.13 – 21.15 are intended to ensure that the MS4 completes an evaluation of pesticide application on city land and identifies alternative products to use if currently applied products contain PFAS compounds. MPCA envisioned this requirement as a one-time inventory, completed within 12 months of permit reissuance, to evaluate, document, and find alternative products to use moving forward. MPCA felt this data will show whether PFAS-containing pesticide use is even an issue at the MS4 level and could then remove the requirement from later permits. They also noted that MN Department of Agriculture has a list of chemical names but is not likely to provide a list of trade names. Note that the MDA list of PFAS compounds is available here: https://www.mda.state.mn.us/environment-sustainability/pfas-pesticide-active-inert-ingredients
MCSC Input:
Pesticide application is already regulated by MN Department of Agriculture and cities have no jurisdiction over the licensed applicators in their city. MDA is already moving to regulate PFAS in pesticides and is better suited to address this concern. In the written response MCSC could suggest modification from “PFAS containing pesticide product” to pesticides with PFAS as active ingredient and request language to clarify this one time requirement (e.g., “must evaluate within 12 months of the issuance date of the permit whether the…”). MCSC suggested that a list of trade names would be simpler to implement than a review of the list of chemical names.

TMDL – section 22
• Numerous reporting requirements have been added to this section, do these reporting requirements solely target the specific data required to track compliance with TMDL WLAs?
• Is this a complete list of all the data needed for TMDL reporting or will there still be a separate process beyond what is listed in the permit?
• Are the listed reporting requirements applied to new BMPs constructed after the date of permit reissuance or will this data be required retroactively for all the MS4’s BMPs that address WLAs?
• Under the reissued permit as currently written, BMPs for new impervious surfaces would require “documented rationale” to justify its use to address WLAs. What type of documentation is expected to support application of a BMP for new impervious to a WLA?
Summary of MPCA Response:
MPCA noted that the requirements are pulled from the current guidance and allows the MPCA to check that BMPs intended to address WLAs are 1) in the subject watershed; 2) implemented after approved TMDLs/WLAs; 3) going above and beyond, not simply meeting non-degradation requirements. MS4s will have to evaluate all reported BMPs against the stated requirements and methods. For some cities that may mean removing BMPs implemented to address new development unless the BMPs reduce pollutant loads below the TMDL baseline condition. MPCA expects TMDL compliance to become a routine part of MS4 permit audits under the reissued permit. Documented rationale can be models demonstrating that BMPs targeting new impervious reduce pollutant load below the TMDL baseline condition.
MCSC Input:
MCSC noted that TMDL WLA reporting requirements should be targeted to the specific information MPCA needs for tracking.

WQ Trading – section 23
• How does MPCA envision the trading program working?
• Where can trading occur (within city, neighboring cities, within contributing watershed)?
• Why has MPCA added separate standards for inspection, maintenance, reporting specific to trading BMPs when the MS4 permit already includes similar requirements?
Summary of MPCA Response:
MPCA staff emphasized that trading is an option to address WLAs, not a requirement. They envision that trading could help justify water quality projects when funding allocation is competitive. The program is currently applied to wastewater treatment facility permits and has been revised as outlined in the draft permit to address MS4s. The WQ trading option is currently intended only to allow trading between the load allocation and the WLA to a specific water body (e.g. shoreline restoration downstream of MS4 outlet to address TSS load). Therefore, any project that reduces pollutants from an MS4 outfall is not eligible for a trade. It is possible that trading could occur between city WLAs but only if the trading MS4 is below their WLA. Trading could be used within a city or within the contributing HUC-8 watershed to the target water body. MPCA can help develop trading plans and WQ trading staff encourage early discussion with their team to determine the scope and applicability of a trading project or trading program. MPCA feels the different inspection and reporting requirements are justified to ensure BMPs are functioning correctly. MPCA will consider options to allow MS4s to work together to address WLAs.
MCSC Input:
A definition of “water quality trading” could be included in permit to help clarify the intended application and use of this option. A simplified program that builds on the existing permit requirements would ease program use and implementation into city operations. A trading option that allows cities to work together to address WLA would be a helpful addition to the program.

Construction Activity – section 28.9
• Why the change from “disturb” to “expose“ for pavement rehabilitation?
• This definition had been consistent with the CSW permit, now it will not be.
Summary of MPCA Response:
MPCA likes “expose” better than “disturb” across all stormwater programs. The CSW division also intends to update the CSW permit definition to use the term “expose” in the next cycle.

Impervious Surface – section 28.18
• Why are sidewalks and trails no longer listed as disconnected?
• The proposed definition is consistent with the CSW definition while 28.9 is proposed to be revised to be different than the CSW permit. What is the reasoning for this change?
Summary of MPCA Response:
This definition is added for consistency with the CSW permit. The only difference is that it directly references MCM 5.

What are your thoughts on the draft permit and MPCA input?

• This topic was modified 1 month, 1 week ago by lisa_admin.

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