RESPONSE TO PUBLIC COMMENTS RECEIVED for the:

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1 RESPONSE TO PUBLIC COMMENTS RECEIVED for the: Minnesota National Pollutant Discharge Elimination System/State Disposal System Construction Stormwater General Permit MNR for the Discharge of Stormwater Associated with Construction Activity. Introduction The Minnesota Pollution Control Agency (MPCA) construction stormwater permit draft was placed on public notice on April 10, 2018 through May 23, The MPCA received 27 comment letters containing between one and 60 comments each. The letters were assigned a number and each individual comment was numbered. Comments have been grouped together according to the permit items as listed in the table of contents. Many general comments were received that were not tied to a specific permit item and these comments are addressed before comments on specific permit items. Letter # Submitted by Letter # Submitted by 1 Association of General Contractors 15 City of Apple Valley 2 Housing First Minnesota 16 Minnesota Chamber of Commerce 3 WSN 17 Minnesota Department of Transportation 4 ISG 18 Builders Association of Minnesota 5 Oneok 19 Riley Purgatory Bluff Creek WSD 6 Minnesota Energy Resources 20 Capitol Region WSD 7 Resource Professionals Alliance 21 Xcel Energy 8 Alpha EMC 22 City of Winona 9 University of Minnesota 23 Minnesota Department of Health 10 Contech Engineered Solutions 24 Ramset-Washington Metro WSD 11 Dakota County 25 Smith Partners, PLLP 12 Vermillion River Watershed 26 Metropolitain Council 13 Minnesota Cities Stormwater Coalition 27 WSB 14 Minnehaha Creek WSD wq-strm2-80d

2 General Comments 1. Comment: Many comment letters contained some type of comment regarding the appearance or organization of the permit. Response: The format of the draft permit is considerably different from the current permit. The comments were generally favorable but some commenters stated that the permit was difficult to read and requested additional modifications or return to the previous format. The MPCA has adopted a new, agency wide, software system that now generates all of the permits issued. MPCA staff is limited in formatting options but worked to produce as readable of a document as possible. In addition to the format change, commenters requested the bulleted list below. (1-4, 4-4, 5-1, 5-2, 7-4, 9-6, 9-13, 9-15, 13-1, 13-3, 13-7, 13-51, 13-53, 15-1, 15-2, 15-11, 15-12, 17-1, 17-4, 17-14, 17-28, 17-30, 18-33, 18-35, 22-1, 24-3, 27-1, 27-3) change the numbering system, change the order of the sections, change the order of items within a section, use less references to other permit items or re-state permit language instead of using references, several areas of the permit or the electronic version of the permit in the manual should include hyperlinks, rule references at the end of each item are confusing or do not direct the reader to the specific rule being used, add descriptors, headings, or titles to the individual items, add spaces to create white space, use bold font for words that have a definition in item 24.1 or other words change the table of contents, Some of the suggestions were outside the capabilities of the software system. MPCA staff made several of the requested changes if it appeared to enhance readability. 2. Comment: Many commenters requested additions or deletions of specific words in many of the items in the draft permit without a justification or reason for the change. (1-1, 1-2, 1-3, 1-6, 1-9, 1-11, 1-14, 4-2, 5-4, 7-1, 7-2, 7-3, 7-7, 7-11, 7-13, 7-14, 12-1, 12-9, 13-2, 13-13, 13-14, 13-19, 13-34, 13-38, 17-35, 18-21) Response: The MPCA made changes where possible and when deemed appropriate and did not make others if the reason for the change was unknown or did not appear to improve the draft permit. 3. Comment: Please reconsider retaining the following language from the current CSGP: if the project is located in a jurisdiction subject to a NPDES/SDS Municipal Separate Storm Sewer System (MS4) permit and that permit has established permanent treatment requirements that include volume reduction, the Permittee(s) can comply with the permanent treatment requirements established under the MS4 permit in lieu of the permanent treatment requirements of this permit. (15-14, 18-1, 25-1) Response: In MPCA s experience many of the ordinances have not been written such that the requirements were at least as stringent as the state requirements or other instances where projects were approved that did not meet the MS4s own ordinance and this provision prevented the MPCA from taking any enforcement action if the permittees plans were approved by the municipality. The MPCA construction stormwater permits issued in 1993, 1998, 2003, and 2008 did not contain this provision and permittees had to meet both the minimum requirements of the general permit and any more stringent requirements found at the local level. The MPCA found that this regulatory setup was not overly burdensome for permittees even when the state vs local requirements on the permittees was substantially different. The 2

3 provision was intended to reduce duplicate regulations, as all regulated MS4 communities should have an ordinance in place that is at least as stringent as the state permit, but in practice actually hampered the MPCA in enforcement of its own permit. The MPCA has determined that it must reserve the right to enforce the requirements of this permit regardless of approvals received from the LGU. Comments on Specific Permit Items 1.3 Construction activity covered by this permit cannot commence until coverage under this permit is effective or, if applicable, until the Minnesota Pollution Control Agency (MPCA) has issued an individual National Pollutant Discharge Elimination System (NPDES)/State Disposal System (SDS) construction stormwater permit for the project. Comment: Add a reference to items 3.3 and 3.4 into item 1.3 (9-1) Response: The MPCA will add the reference to the permit language. Comment: This section includes the following text: Construction activity covered by this permit cannot commence until coverage under this permit is effective or, if applicable, until.... The meaning of the phrase if applicable is unclear, in this context. What rule or permit provision(s) are the relevant standards to determine applicability? The applicant must know this information to be able to make this determination. Please provide this information as part of this CSGP section. Please provide appropriate hyperlinks. (13-5, 18-2) Response: The language in this item, if applicable, until the MPCA has issued an individual permit is needed in the rare instance when the MPCA might provide permit coverage for stormwater using an individual permit, in which case the general permit is not needed. See the General Provisions section of the permit and also the criteria for general permits can be found in MN This permit covers ongoing projects covered under any previous construction stormwater permit that are not complete on the issuance date of this permit. Permittees must either remain in compliance with the previous permit and terminate coverage within 18 months of the issuance date of this permit or comply with this permit, including updating the Stormwater Pollution Prevention Plan (SWPPP), within the 18-month period. Permittees of previously permitted projects are not required to incorporate any additional requirements regarding the permanent stormwater treatment system included in this reissued permit. Comment: Commenter states the last sentence of this section is confusing. Permittees of previously permitted projects are not required to incorporate any additional requirements regarding the permanent stormwater treatment system included in this reissued permit. The first part of this section lists two options for ongoing projects covered under the current CSGP. Does the condition listed in the sentence above apply to both of those options? Please clarify. (13-6, 18-3) Response: The condition does apply to both options. Any project permitted before the issuance date of the 2018 permit does not need to make revisions to the permanent stormwater treatment to meet the new requirements. Comment: One commenter recommends grandfathering through January 1, 2019 instead of 18 months from the permit issuance date because permit changes are minor and an 18 month time frame is unnecessary. (20-2) 3

4 Response: The MPCA believes a grandfathering period of 18 months is a reasonable amount of time and is consistent with the current permit and does not agree there should be a shorter grandfathering period. 1.7 Coverage for projects that extend beyond the expiration date of this permit remains effective for a grace period covering project completion and Notice of Termination (NOT) submittal. If Permittees cannot complete projects during the grace period, the MPCA will extend coverage under the next permit and permittees must comply with the requirements of the new permit including updating the SWPPP. Permittees are not required to follow changes to the permanent stormwater treatment section of the next permit. Comment: One commenter asks if the grace period mentioned in this item is the 18 month timeframe referred to in item 1.6. (24-2) Response: The grace period mentioned in item 1.7 will be defined in the next permit issuance (approximately August of 2023). The intent is that the grace period will likely be the same 18 months that is allowed in item 1.6 for this permit. 2.5 This permit does not authorize stormwater discharges associated with industrial activity except for construction activity. Permittees must obtain coverage for discharges associated with industrial activity under a separate NPDES/SDS permit once day-to-day operational activities commence even if construction is ongoing. Comment: One commenter request clarification regarding when a borrow pit might need a separate permit for industrial activity. (17-2) Response: Borrow pits serving a single permitted project can be covered under the same construction permit. If the borrow pit is serving multiple construction projects an industrial permit must be obtained. 2.6 This permit does not authorize discharges from non-point source agricultural and silvicultural activities excluded from NPDES permit requirements under 40 CFR pt (e). Comment: One commenter requests further explanation that permit coverage is needed for some projects resulting in greater than one acre of land disturbance in an agricultural or silvicultural contexts. (13-8) Response: The MPCA relies on the wording of exemptions in 40 CFR 122.3(e) and fact sheets created by the EPA and the MPCA to describe in more detail when permit coverage is needed in agricultural and silvicultural contexts. If a project owner or LGU is questioning whether or not a particular project needs permit coverage, they can call the MPCA construction stormwater program for a determination. 2.7 This permit does not authorize stormwater discharges to Prohibited, Restricted, Special or Impaired waters unless permittees follow the additional stormwater requirements in item 23.1 through Comment: One commenter would like this item to be modified to include from projects within one mile (aerial radius measurement) to be clear where the limitation of coverage would apply. (13-9, 18-4) 4

5 Response: The MPCA believes that this limitation of coverage is already covered by current draft permit language. Item 2.7 refers to 23.1 through and within that range item 23.2 includes a clear description of where the limitation of coverage applies This permit does not authorize discharges to wetlands unless the permittee complies with the requirements in item 22.1 through Comment: One commenter would like this item to be modified to include from projects within one mile (aerial radius measurement) because without this additional language, this limitation of coverage would apply too broadly. (13-10, 18-5) Response: The permit requirement for discharges to wetlands has never been limited to within one mile of a wetland. Although found in Appendix A of previous permits, this requirement is for any projects that have discharges with the potential for significant adverse impact to wetlands. 3.3 For projects or common plans of development or sale that disturb less than 50 acres or do not discharge stormwater within 1 mile of a special or impaired water, permittees do not need to submit the SWPPP with the application. Permit coverage for these projects is effective upon application and completing the payment process. Comment: The commenter requests the removal of or do not discharge stormwater within one mile of a special or impaired water because it is the commenters understanding that no projects under 50 acres requires the submission of the SWPPP with the application. Another commenter likes the change from a 7 day waiting period to upon application and completing the payment process. (9-2, 20-3) Response: The MPCA is keeping the language as written because projects over 50 acres in size that are not within one mile of a special or impaired water also do not need to submit the SWPPP with the application. Comment: Commenter requests that aerial radius measurement be added to this item for consistency. (13-11, 8-6) Response: MPCA has revised the permit to reflect this comment. Comment: One commenter asks why aren t permit applicants required to submit their SWPPPs for developments under 50 acres when they re required to compile one? The commenter understands what MPCA staff do not have time to review all SWPPPs but believes that having them on file would be beneficial to MPCA inspectors. (24-4) Response: The commenter is correct that the MPCA does not have the staff to be able to review all SWPPPs for permitted projects. The permit requires the SWPPP, including any changes to it, be kept on site during normal working hours and MPCA inspectors regularly request the SWPPP when doing a site inspection. 3.4 For certain projects or common plans of development or sale disturbing 50 acres or more, the complete SWPPP must be included with the application and submitted at least 30 days before the start of construction activity. This applies if there is a discharge point on the project within one mile (aerial radius measurement) of, and flows to, a special water listed in item 23.2 through or an impaired water as described in item

6 Permit coverage for these projects is effective upon submitting the application and complete SWPPP, completing the payment process and receiving a determination from the MPCA that the review of the SWPPP is complete. The determination may take longer than 30 days if the SWPPP is incomplete. If the MPCA fails to contact the permittees within 30 days of application receipt, coverage is effective 30 days after completing the payment process. Comment: Is the word also missing after the word this? (5-3) Response: This section is worded as intended. A SWPPP review is required if the project is over 50 acres in size and has a discharge point within one mile of a water listed in item Comment: Commenter requests the MPCA commit to doing an initial review early during the 30 day review period. Permittees must have an identified timeline as to when the approval of the SWPPP can be expected. (16-1) Response: The MPCA has been conducting SWPPP reviews of this nature since It has been the intention and practice to provide a timely SWPPP review and to work with the applicant to have the permit issued within the 30 day timeframe. The MPCA has been successful with this approach and believes no changes to the permit are warranted. Comment: One commenter requests a clarification as to what constitutes contact in the sentence If MPCA fails to contact the permittees within 30 days of application receipt, coverage is effective 30 days after completing the payment process. (24-5) Response: The MPCA will most likely use the addresses provided by the applicants at the time of application but reserves the right to send U.S postal service correspondence or even contact the applicants by phone. 3.5 The application requires listing all persons meeting the definition of owner and operator as permittees. The operator is jointly responsible with the owner for all terms and conditions of this permit except for the development of the SWPPP as described in item 5.2. Comment: Commenter states that the new language has changed the responsibilities of the operator and holds parties liable for an action in which they have no part. The commenter requests that the agency retain the language under Part II.B.2 of the current permit. (2-1) Response: The agency did not intend to change the responsibilities for the operator. The agency will revise the draft permit language such that the responsibilities between the owner and operator remain the same as in the current permit. 3.6 Permittees will receive coverage notification in a manner determined by the MPCA. Comment: Commenter is unsure of the intent of this item. Another commenter asks what form will the MPCA confirm coverage because they currently require permit applicants for their watershed district to submit a copy of their NPDES permit coverage card to keep on file before issuing a permit to the applicant. Another commenter requests that the MPCA continue to issue a coverage card with each permit application as they are easier to read than the coverage letter. (9-3, 24-1, 27-2) 6

7 Response: The MPCA intends on notifying permittees via however, the MPCA reserves the right to notify permittees of coverage using other means if necessary. The MPCA does not require the coverage card to be posted at each site. The MPCA will continue to issue a coverage letter to each applicant and intends to revise the letter to better present the coverage information to the reader. 4.4 Permittees may terminate permit coverage prior to completion of all construction activity if they meet all of the following conditions: a. construction activity has ceased for at least 90 days; and b. at least 90 percent (by area) of all originally proposed construction activity has been completed and permanent cover has been established on those areas; and c. on areas where construction activity is not complete, permanent cover has been established; and d. the site complies with item 13.3 through After permit coverage is terminated under this item, any subsequent development on the remaining portions of the site will require permit coverage if the subsequent development itself or as part of the remaining common plan of development or sale will result in land disturbing activities of one (1) or more acres in size. Comment: One commenter states: As written, this section appears to allow for the following hypothetical: A project disturbing 1.5 acres gets started with the appropriate CSGP coverage. After completing work on half the site, stopping work, and meeting the conditions in this section, the permittee terminates permit coverage. After 90 days, the permittee starts work on the rest of the site as a separate and independent project. Now, the area to be disturbed is only ¾ of an acre. Thus, a new permit is not required. Work can proceed without any permit coverage or protection. Please revise the language of this section so that this hypothetical is not allowable. (13-12) Response: The MPCA disagrees that this scenario is allowable. Item 4.4.b requires that 90% of the construction activity has been completed to qualify for termination under this item. 5.5 The SWPPP must include the calculations developed for temporary sediment basins and the permanent stormwater treatment system. Comment: One commenter states that several of the SWPPP elements do not belong in the contracts for the project and permittees should be allowed to reference the location of the SWPPP items. (17-3) Response: The MPCA does not specify the format of the SWPPP. It is acceptable to provide references within the SWPPP narrative to reference required elements of the SWPPPP that appear in other locations of the plan and contract. 5.9 The SWPPP must include a map of all surface waters, existing wetlands, and stormwater ponds or basins that can be identified on maps such as United States Geological Survey 7.5 minute quadrangle maps, the National Wetland Inventory map or equivalent maps and are within one mile (aerial radius measurement) from the project boundaries that will receive stormwater from the construction site, during or after construction. The SWPPP must identify if the surface water is a special or impaired water. 7

8 Comment: Add language similar to the current permit regarding identifying receiving waters within one mile of the project with an arrow on plan sheets. (4-1) Response: The MPCA believes that a map indicating receiving waters with an arrow and distance meets the mapping requirement as described in the permit and the additional words suggested are not necessary Permittees must identify locations of temporary buffer zones as required in item 9.17 and permanent buffer zones as required in item 23.22, on plan sheets in the SWPPP. Comment: One commenter suggested adding clarity to this section by adding 50 and 100 feet to the buffer zones. (5-3) Response: The MPCA changed this section to include 50 and 100 foot references and removed the word temporary to be consistent with other items in the permit The SWPPP must describe the methods used for permanent cover of all exposed soil areas. Comment: Change permanent cover to permanent stabilization. (7-5) Response: The term permanent cover is defined in the permit and the MPCA believes the term is being used correctly Permittees must document in the SWPPP, all trained individuals identified in item 21.4 through Documentation must include: a. names of personnel required to be trained; and b. dates of training and name of instructor(s) and entity providing training; and c. content of training course. If permittees do not know the names of the individuals at the time of application, the permittees must ensure they document training before construction activity commences. Comment: One commenter requests clarification if training in this item is required prior to the commencement of construction activity. (13-15) Response: The permit requires that permittees have a complete SWPPP prior to applying for permit coverage. Permit coverage is required prior to the commencement of construction activity. A complete SWPPP includes identifying trained individuals, thus training is required prior to the commencement of construction activity. Comment: Please provide some details about what is expected in the documentation for content of training course. Please state whether a syllabus and/or table of contents is sufficient to meet this requirement. (13-16) Response: The MPCA would accept a syllabus and/or a table of contents but also encourages permittees to keep course materials for future reference. 8

9 5.21 The SWPPP must identify a person knowledgeable and experienced in the application of erosion prevention and sediment control BMPs who will coordinate with all operators on site and oversee the implementation of the SWPPP. Comment: Commenter suggests this item be re-written and believes the operator should identify a person who will oversee the implementation of the SWPPP and who will schedule the work and coordinate with all operators on site. (1-5, 7-6) Response: The draft permit requires the owner to develop the SWPPP and not the contractor (see item 5.2). The SWPPP must identify the person who is overseeing the implementation of the SWPPP. Therefore, this responsibility resides with the owner. Although the contractor may be a part of this decision, ultimately it is the responsibility of the owner. The MPCA believes that all of the other concepts suggested in this comment are already contained in the draft permit in items 5.21 and Comment: One commenter states that the use of the word operators is confusing in this item and requests the use of a different term for clarity. (13-17, 18-7) Response: The permit has been modified to reflect the comment and to provide clarity The SWPPP must identify the person(s) responsible for long-term operation and maintenance of permanent stormwater treatment systems. Comment: One commenter request this item be modified to provide for the possibility that an entity or organization may be responsible for future maintenance. (13-18, 18-8) Response: The permit has been modified to reflect the comment The SWPPP must include any site assessments for groundwater or soil contamination required in item Comment: One commenter states this will be confusing for small site owners and greenfield sites with no reasonable potential for contamination. Commenter suggests the MPCA should modify the permit to state that the site assessment form should be required for sites with known or suspected contamination. (12-1) Response: The MPCA expects all permittees proposing infiltration to follow the MPCA site screening assessment checklist or conduct their own assessment. The MPCA included the option of providing a permittees own assessment to address a greenfield site or a site with no reasonable potential for contamination. An alternate assessment could be complicated and detailed if warranted or could be a simple analysis in greenfield situations described by the commenter The SWPPP must account for the following factors in designing temporary erosion prevention and sediment control BMPs: a. the expected amount, frequency, intensity, and duration of precipitation; and b. the nature of stormwater runoff and run-on at the site, including factors such as expected flow from impervious surfaces, slopes, and site drainage features; and 9

10 c. if stormwater flow is channelized, peak flowrates and total stormwater volume to minimize erosion at outlets and to minimize downstream channel and streambank erosion; and d. the range of soil particle sizes expected to be present. Comment: Commenter states that draft language ( downstream channel and streambank erosion ) would expose permittees to enforcement action due to factors beyond their ability to reasonably control. (2-2) Response: This requirement originates from the EPA 2009 Effluent Limitations Guidelines and Standards for the Construction and Development (C&D Rule) Point Source Category Rule at 40 Code of Federal Regulations pt. 450 which changed after the MPCA issued the current permit. The MPCA will revise this item to reflect the final C&D rule and EPA s construction permit. Comment: The permit requires the SWPPP to account for numerous factors (such as rainfall intensity, stormwater flow, soil type) in designing temporary BMPs, but does not explain how those factors should be used. We request clarification or guidance on what would be acceptable methods of accounting for such factors during design. (17-6) Response: The level of proper analysis is determined by the permittee. For example, evaluating rainfall characteristics is important in order to identify specific factors that need to be accounted for in the design of stormwater controls. Each of these specific design factors correspond to the C&D rule requirements in 40 CFR (a)(2)(5). It is important to consider precipitation characteristics so that earth-disturbing activities can be planned during periods with a lower risk of precipitation and so that erosion and sediment control practices can be designed to convey and manage the precipitation that is expected to occur. 6.2 One of the individuals described in item 21.4 or item 21.5 or another qualified individual must complete all SWPPP changes. Changes involving the use of a less stringent BMP must include a justification describing how the replacement BMP is effective for the site characteristics. Comment: One commenter requested the 2 nd sentence be removed from item 6.2 because inspections and maintenance requirements ensure that ineffective BMP s are replaced. (15-3) Response: MPCA expects SWPPPs to be prepared by individuals trained in SWPPP design which includes proper BMP selection. This item allows permittees to use a less stringent BMP than specified in the SWPPP as long as the permittee provides a justification. This ensures that the replacement BMP is still appropriate for the site conditions as opposed to discovering an ineffective BMP in the field. 6.3 Permittees must amend the SWPPP to include additional or modified BMPs as necessary to correct problems identified or address situations whenever there is a change in design, construction, operation, maintenance, weather or seasonal conditions having a significant effect on the discharge of pollutants to surface waters or groundwater. Comment: Commenter inquires guidance on the term significant effect. (17-7) Response: The permit requires effective BMP s to be used at all times. If a change in site conditions occurs that is causing BMP s to become ineffective, additional or modified BMP s may be necessary. Ineffective BMP s will be discovered during inspections if pollutants are discharging from the site or into surface waters. The MPCA would consider this a significant effect. 10

11 8.2 Permittees must delineate the location of areas not to be disturbed before work begins. Comment: Commenter requests additional details be added to clarify that showing these areas on plan sheets is adequate. (6-1) Response: The current permit requires areas not to be disturbed to be marked in the field in Part IV.B.1. The MPCA believes these areas must be marked in the field such that all equipment operators are aware of these areas at all times and to ensure other individuals on the site who do not have access to the plan sheets are also aware of areas not to be disturbed. This is not intended to apply to the entire site boundary but areas that need protection such as buffer zones, wetlands or any areas the owner wishes to preserve. 8.3 Permittees must minimize the need for disturbance of portions of the project with steep slopes. When steep slopes must be disturbed, permittees must use techniques such as phasing and stabilization practices designed for steep slopes (e.g., slope draining and terracing). Comment: It is unclear what is meant by the term slope draining. Does this mean slope diversions, bypassing stormwater around a slope using down drains or flumes, or diverting drainage from a slope using berms and dikes? We request clarification on what is meant by the term slope draining. (17-9) Response: Any of the methods suggested by the commenter would satisfy this requirement if the method is effective. See Protecting Water Quality in Urban Areas Ch for more information on slope draining. 8.4 Permittees must stabilize all exposed soil areas, including stockpiles. Stabilization must be initiated immediately to limit soil erosion when construction activity has permanently or temporarily ceased on any portion of the site and will not resume for a period exceeding 14 calendar days. Stabilization must be completed no later than 14 calendar days after the construction activity has ceased. Stabilization is not required on constructed base components of roads, parking lots and similar surfaces. Stabilization is not required on temporary stockpiles without significant silt, clay or organic components (e.g., clean aggregate stockpiles, demolition concrete stockpiles, sand stockpiles) but must provide sediment controls at the base of the stockpile. Comment: Commenter requests deletion of must provide sediment controls at the base of the stockpile because it is redundant with item 9.9. (7-8) Response: The MPCA believes this requirement should be left in both places for emphasis. 8.8 Permittees must not use mulch, hydromulch, tackifier, polyacrylamide or similar erosion prevention practices within any portion of the normal wetted perimeter of a temporary or permanent drainage ditch or swale section with a continuous slope of greater than 2 percent. Comment: Commenter requests that this requirement should be based on shear stress calculations and not based on slope. (9-4) 11

12 Response: The MPCA added this option for ditch stabilization to the draft permit based on stakeholder input. The MPCA believes the requirement should be easy to understand and implement for all permittees. The MPCA has found that ditch slopes between 0 and 2 percent generally result in shear stress levels low enough to not cause erosion. However, this does not prevent designers from requiring blanket in ditch bottoms where shear stresses have been calculated to be high enough to cause erosion. Comment: One commenter suggests that this item is unclear because ditches have both a side slope and a longitudinal or profile slope and requests this section be modified. (13-20, 18-9) Response: The normal wetted perimeter of a ditch includes only a small portion of the side slope of a ditch. Side slopes of ditches would almost never be less than two percent for the majority of ditches that are constructed under this permit. For these reasons, the MPCA does not believe that this item needs clarification. Comment: One commenter states they can understand flexibility in temporary stabilization methods for ditches/swales, but they believe erosion control blanket should be required for permanent stabilization within 200 of the discharge point for all conveyances, regardless of slope. (24-8) Response: The MPCA believes this change in the permit will still be protective of surface waters. As with all BMP requirements in the permit, If the selected BMP is found to be inadequate at minimizing erosion from ditches or swales, another more effective BMP must be utilized The permittee must not disturb more land (i.e., phasing) than can be effectively inspected and maintained in accordance with item 11.1 through Comment: Commenter requests stabilization as required by item 8.4 through 8.6 be included. (7-9) Response: The MPCA believes that this item as written conveys the intent of the requirement and no changes are necessary. Comment: How will the MPCA determine that the permittee has disturbed more land than can be inspected? (17-10) Response: If MPCA inspectors discover the permittee does not have up to date inspection records covering the whole site and/or maintenance activities are not performed across the entire site due to the area of disturbance being too large for assigned staff to manage, this may be considered a violation. 9.2 Permittees must establish sediment control BMPs on all downgradient perimeters of the site and downgradient areas of the site that drain to any surface water, including curb and gutter systems. Permittees must locate sediment control practices upgradient of any buffer zones. Permittees must install sediment control practices before any upgradient land-disturbing activities begin and must keep the sediment control practices in place until they establish permanent cover. Comment: Commenter states sediment controls should be allowed to be removed before permanent vegetation is established. Commenter requests guidance on situation where this is allowed. (17-11) Response: The MPCA believes that in order to minimize the discharge of sediment, all sediment controls must remain in place until permanent cover is established. 12

13 9.3 If downgradient sediment controls are overloaded, based on frequent failure or excessive maintenance requirement, permittees must install additional upgradient sediment control practices or redundant BMPs to eliminate the overloading and amend the SWPPP to identify these additional practices as required in item 6.3. Comment: Commenter suggests that installing additional erosion prevention practices should also be an option when sediment controls are failing frequently. (1-8, 7-10) Response: The permit already requires effective erosion prevention practices. Also, item 11.4 states Permittees must repair, replace or supplement all nonfunctional BMPs with functional BMPs. Comment: One commenter inquires about the definition of frequent and excessive. (17-12) Response: This item requires permittees who discover repeated failures of a BMP under normal circumstances (not due to extreme rain events) to install additional or redundant BMP s. For example, if each time a small rain event occurs a BMP is overloaded, the permittees must install additional or redundant BMP s. 9.6 Permittees must re-install all sediment control practices adjusted or removed to accommodate short-term activities such as clearing or grubbing, or passage of vehicles, immediately after the short-term activity is completed. Permittees must re-install sediment control practices before the next precipitation event even if the short-term activity is not complete. Comment: One commenter would like this item to be modified to include a size of rain event to serve as a threshold for the requirement to re-install practices and states that small rain events will not jeopardize the site if practices are not re-installed. (13-22, 18-11) Response: The MPCA believes that perimeter controls should be in place at all times when soils that do not have permanent cover are draining to the area where the perimeter controls are required. However, the MPCA understands the need for short term activities where the perimeter control needs to be removed so it is not damaged. The MPCA believes that in the event of any precipitation event the perimeter controls must be reinstalled to prevent sediment discharge from the site. 9.7 Permittees must protect all storm drain inlets using appropriate BMPs during construction until they stabilize all sources with potential for discharging to the inlet. Comment: One commenter asks if inlet protection is needed until 70% vegetated cover has been established or just until temporary stabilization practices have been employed. (13-21, 18-10) Response: The MPCA has modified this item to make it clear that inlet protection is required until permanent cover has been established on all areas that drain to the inlet. 9.8 Permittees may remove inlet protection for a particular inlet if a specific safety concern (e.g. street flooding/freezing) is identified by the permittees or the jurisdictional authority (e.g., 13

14 city/county/township/minnesota Department of Transportation engineer). Permittees must document the need for removal in the SWPPP. Comment: One commenter would like this item to be modified to include the concept of best professional judgement to identify a potential safety problem. Another commenter requests that this item can be applied across an entire municipality due to freezing conditions without a justification for each individual inlet. (13-23, 15-4, 18-12) Response: The MPCA believes that this item does not need be modified. A jurisdictional authority is already allowed to use their judgement when determining if inlet protection can be removed. The MPCA believes that not every inlet protection will cause a safety concern and should be evaluated individually. The MPCA would like to stress that this item does not allow for a blanket statement saying that all inlet protection can be removed from a project site and it is to be used for particular inlets where safety is a concern. Comment: Commenter requests that the permit allow temporary removal of inlets upgradient from land disturbance for the purpose of causing incoming stormwater to bypass the project. (17-13) Response: The draft permit does not require inlet protection if the drainage area of the inlet is not disturbed. 9.9 Permittees must provide silt fence or other effective sediment controls at the base of stockpiles. Comment: Commenter requests the permit be modified to state that stockpiles located in the interior of a site do need perimeter controls. Another commenter states the draft language has been changed to increase the agency s ability to fine permittees and requests the current language be retained. Another commenter suggests this item be modified to include some flexibility in stockpile sediment control such as within 50 feet of the stockpile and even allowing shared use of other site sediment controls if the design, capacity, and drainage patterns allow. Several comments believe the addition of at the base in this requirement adds clarity. (1-7, 1-10, 2-3, 7-12, 21-2, 27-8) Response: The MPCA believes that stockpiles should have perimeter control at the base regardless of location on the site or proximity to the perimeter control at the edge of the site. The change in permit language is needed to clarify the requirement for stockpiles that the MPCA always intended. Stockpiles have steep slopes and are highly erodible and need perimeter control in addition to the perimeter control found at the downgradient edge of the site in order to work together to prevent discharge of sediment from the site. Comment: Commenter suggests including either on downgradient perimeters or, around entire base of stockpile. Another commenter requests language regarding access by equipment. (9-5, 13-24, 17-8, 18-13) Response: The permit language has modified to include on downgradient perimeters and this should allow equipment access to the stockpile on the upgradient side. Additionally, item 9.6 allows for temporary removal of sediment controls for short-term activities. Comment: Commenter requests that the term silt fence be removed from this item because readers may believe that silt fence is the only BMP allowed by this item. (17-8) Response: The MPCA believes the draft permit language or other effective sediment controls allows for the use of other BMP s. 14

15 9.11 Permittees must install a vehicle tracking BMP to minimize the track out of sediment from the construction site or onto paved roads within the site. Comment: Commenter suggests adding the examples of tracking BMPs found in the current permit. (12-2) Response: The permit requires SWPPP designers and site managers to be trained. The MPCA expects this training to cover the types of vehicle tracking BMP s available on construction sites Permittees must use street sweeping if vehicle tracking BMPs are not adequate to prevent sediment tracking onto the street. Comment: One commenter requests this item to be modified to specify the appropriate and required timing and frequency for street sweeping. (13-25) Response: The draft permit requires inspection of all BMPs once per week and after rainfall events greater than one half inch. This ensures street sweeping will be performed if vehicle tracking BMPs have failed at least once per week. Additionally, item 11.6 requires permittees to remove sediment from paved surfaces within one calendar day of discovery or, if applicable, within a shorter time to avoid a safety hazard to users of public streets In any areas of the site where final vegetative stabilization will occur, permittees must restrict vehicle and equipment use to avoid soil compaction. Comment: Commenter states that this requirement is vague and is not enforceable. Another commenter states that this requirement is unrealistic and unworkable and suggests prohibiting compaction only in areas that are to be infiltration BMPs. Another commenter states that this will not be possible on roadside projects. (12-3, 13-26, 17-5, 18-14) Response: The MPCA included a similar requirement in the current permit in response to the EPA Construction & Development (C & D) rule requiring construction permits to include a provision for avoiding soil compaction. There are many sites where soil compaction can clearly be avoided and the MPCA expects permittees to attempt to do so. The MPCA agrees that additional flexibility may be needed on certain projects and will add the term minimize to this item. Additionally, there is a requirement in item 16.5 that requires infiltrations systems to be protected from compaction Permittees must direct discharges from BMPs to vegetated areas unless infeasible. Comment: One commenter states that this requirement confusing and overly broad. (13-27, 18-15) Response: This requirement was added to the 2013 permit because of the EPA C & D rule and must be included in state permits. There is a provision in both the C & D rule and the permit requirement for an infeasibility determination that assists permittees when determining where to discharge from BMPs. 15

16 9.17 Permittees must preserve a 50 foot natural buffer or, if a buffer is infeasible on the site, provide redundant (double) perimeter sediment controls when a surface water is located within 50 feet of the project's land disturbances and stormwater flows to the surface water. Permittees must install perimeter sediment controls at least 5 feet apart unless limited by lack of available space. Natural buffers are not required adjacent to road ditches, judicial ditches, county ditches, stormwater conveyance channels, storm drain inlets, and sediment basins. If preserving the buffer is infeasible, permittees must document the reasons in the SWPPP. Comment: Several comments support the addition of the 5 distance between redundant perimeter sediment controls. Some commenters stated the inclusion of unless limited by lack of available space is a considerable loophole and creates little incentive to maintain properly spaced redundant controls. (9-7, 12-4) Response: Because this general permit covers many types of construction sites, the MPCA believes that flexibility is needed where space is limited. Comment: One commenter requests that this item be clarified whether the 50 foot buffer is temporary, permanent or both. (13-28, 15-5, 18-16) Response: This item requires a 50 foot buffer or redundant controls. The buffer is not classified as temporary or permanent. If there is construction planned for the buffer, it must be included in the SWPPP for the project and redundant controls would be required. Additionally, permittees must include why it was infeasible to preserve the buffer in the SWPPP. If construction is not planned inside the buffer area, then it should remain until construction activity covered under this permit is completed. Item 5.12 has been modified to remove the word temporary for consistency with other items in the draft permit. Comment: Commenter asks if redundant BMP s must be different types or the same. Commenter also requests to allow erosion prevention to be used as one of the perimeter control BMP s. Commenter also request that if sheet piling is being used the draft permit should not require redundant sediment control BMP s. (17-15) Response: The draft permit allows the BMP s chosen for this item to be either the same or they can be different. Erosion control BMP s are already required and the MPCA believes that erosion control BMP s must be used in conjunction with redundant perimeter controls within 50 of a surface water. The permit has been modified to state that properly installed, effective sheet piling is considered a redundant BMP. Comment: One commenter states the area between the perimeter controls should be stabilized. (27-7) Response: All exposed soils on the site must be stabilized within the timeframes specified in the permit Permittees must discharge turbid or sediment-laden waters related to dewatering or basin draining (e.g., pumped discharges, trench/ditch cuts for drainage) to a temporary or permanent sedimentation basin on the project site unless infeasible. Permittees may dewater to surface waters if they visually check to ensure adequate treatment has been obtained and nuisance conditions (see Minn. R , subp. 2) will not result from the discharge. If permittees cannot discharge the water to a sedimentation basin prior to entering a surface water, permittees must treat it with appropriate BMPs such that the discharge does not adversely affect the surface water or downstream properties. Comment: One commenter would like this item to be modified to include to provide controls for discharging dewatering or basin draining water to a curb & gutter or a MS4. (13-29) 16

17 Response: The term surface waters includes curb & gutters and drainage systems therefore, no change is warranted. Comment: Commenter states Would like to see numerical requirements for dewatering practices (NTU and ph) to remove any gray areas associated with nuisance conditions and dewatering. (27-10) Response: The MPCA relies on the nuisance condition standard found in subp.2 for this permit. Discharge limits for activities such as dewatering are more appropriately developed in a rule making process which is beyond the scope of this permit reissuance If permittees must discharge water containing oil or grease, they must use an oil-water separator or suitable filtration device (e.g., cartridge filters, absorbents pads) prior to discharge. Comment: One commenter suggests this item be modified to include language regarding the installation and operation of oil-water separators in a functional manner and in accordance with relevant manufacturer specifications and accepted engineering practices. (13-30) Response: Item 7.2 requires that all BMPs be selected, installed and maintained in accordance with relevant manufacturer specifications and accepted engineering practices Permittees must discharge all water from dewatering or basin-draining activities in a manner that does not cause erosion in receiving channels, at discharge points, on downslope properties or inundation in wetlands causing significant adverse impact to the wetland. Comment: A permittee could be held liable for erosion several miles from the site even when the permittees action did not cause the issue in question. (2-4) Response: The MPCA agrees that adverse impacts which the permittee is held liable for, should be limited to discharges that can be attributed to the site and has modified the permit to reflect this If permittees use filters with backwash water, they must haul the backwash water away for disposal, return the backwash water to the beginning of the treatment process, or incorporate the backwash water into the site in a manner that does not cause erosion. Comment: One commenter states that this requirement appears to allow for backwash water to be managed on-site if it does not cause erosion. The commenter asks how polluted or contaminated is filter backwash water and is the MPCA comfortable with such water being infiltrated on-site. (13-31) Response: The MPCA believes that any common constituents found in backwash water discharge that is managed onsite will be attenuated by soil absorption or other natural processes Permittees must ensure a trained person, as identified in item 21.5, will inspect the entire construction site at least once every seven (7) days during active construction and within 24 hours after a rainfall event greater than 1/2 inch in 24 hours. 17