AUTHORIZATION TO DISCHARGE STORMWATER ASSOCIATED WITH CONSTRUCTION ACTIVITY UNDER THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM/STATE DISPOSAL SYSTEM PROGRAM
Link to the 2013 Construction Stormwater Permit - pdf version File:Wq-strm2-68a.pdf
PART I. PERMIT COVERAGE AND LIMITATIONS
I.A. PERMIT COVERAGE
- This permit is required for construction activity that results in land disturbance of equal to or greater than one acre or a common plan of development or sale that disturbs greater than one acre, and authorizes, subject to the terms and conditions of this permit, the discharge of stormwater associated with construction activity.
Construction activity does not include a disturbance to the land of less than five (5) acres for the purpose of routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, or original purpose of the facility. Pavement rehabilitation that does not disturb the underlying soils (e.g., mill and overlay projects) is not considered construction activity.
- This permit covers all areas of the State of Minnesota.
- Coverage under this permit is not required when all stormwater from construction activity is routed directly to and treated by a “treatment works”, as defined in Minn. Stat. § 115.01, subd. 21, that is operated under an individual NPDES/SDS permit with a Total Suspended Solids effluent limit for all treated runoff.
- Previously Permitted Ongoing Projects: Permittee(s) of ongoing projects covered initially under the previous MPCA‐issued NPDES/SDS Construction Stormwater General Permit (issuance date August 1, 2008) are granted coverage under this reissued permit.
a. The Permittee(s) of those ongoing projects shall amend the SWPPP for the project to meet the requirements of this reissued permit no later than 18 months after the issuance date of this reissued permit if the termination‐of‐coverage requirements in Part II.C. will not be met within 18 months of the issuance date of this reissued permit and shall thereafter comply with this permit. However, additional permanent treatment required in this reissued permit is not required for previously permitted projects.
b. If the previously permitted ongoing project will meet the termination‐of‐coverage requirements in Part II.C. within 18 months of the issuance date of this reissued permit, the Permittee(s) shall comply with the 2008 construction general permit until the project is complete and a Notice of Termination (NOT) consistent with Part II.C. of this reissued permit is submitted.
c. If a previously permitted ongoing project will not be able to meet the terms and conditions of this reissued permit (other than the additional permanent treatment requirement) and will continue longer than 18 months after the issuance date of this permit, the Permittee(s) shall apply for an individual permit in accordance with Minn. R. ch. 7001.
I.B. LIMITATIONS OF COVERAGE
This permit does not authorize discharges related to the following activities:
- . Discharges or releases that are not stormwater (except those non‐stormwater discharges
- The placement of fill into waters of the state requiring local, state or federal authorizations (such as U.S. Army Corps of Engineers Section 404 permits, Minnesota Department of Natural Resources Public Waters Work Permits or Local Governmental Unit Wetland Conservation Act replacement plans or determinations).
- Discharges associated with industrial activity except for construction activity. Discharges associated with industrial activity may need to obtain coverage under a separate NPDES/SDS permit once day‐to‐day operational activities commence even if construction is ongoing.
- Discharges from non‐point source agricultural and silvicultural activities excluded from NPDES permit requirements under 40 CFR pt. 122.3(e).
- Discharges to the waters identified below unless the requirements of Appendix A are complied with:
a. Discharges into outstanding resource value waters as listed in Minn. R. 7050.0180, subp. 3, 4, 5, 6, 6a and 6b.
b. Discharges into trout waters as listed in Minn. R. 6264.0050, subp. 2 and 4.
c. Discharges into wetlands as defined in Minn. R. 7050.0186 subd.1a.B.
d. Discharges from projects that have not completed applicable Environmental Review requirements under state or federal laws.
e. Discharges that adversely impact or contribute to adverse impacts on a state or federally listed endangered or threatened species or adversely modify a designated critical habitat.
f. Discharges that adversely affect properties listed or eligible for listing in the National Register of Historic Places or affecting known or discovered archeological sites.
- Discharges to waters identified as impaired pursuant to section 303(d) of the federal Clean Water Act (33 U.S.C. § 303(d)) where the identified pollutant(s) or stressor(s) are phosphorus (nutrient eutrophication biological indicators), turbidity, dissolved oxygen, or biotic impairment (fish bioassessment, aquatic plant bioassessment and aquatic macroinvertebrate bioassessment), and with or without a U.S. Environmental Protection Agency (USEPA) approved Total Maximum Daily Load (TMDL) for any of these identified pollutant(s) or stressor(s), unless the applicable requirements of Part III.A.8. are met.
PART II. SUBMITTING THE APPLICATION
II.A. PREREQUISITE FOR SUBMITTING A PERMIT APPLICATION
The owner must develop an accurate and complete SWPPP in accordance with Part III. (Stormwater Discharge Design Requirements) of this permit prior to submitting the application for coverage. The SWPPP is not required to be submitted to the MPCA (unless the project size is 50 acres or more and will discharge to certain waters as described in Part II.B.1.b.) but is to be retained by the owner in accordance with Part III.E. (Record Retention). The owner’s failure to prepare an accurate and complete SWPPP prior to submitting the application is grounds for MPCA to revoke the permit.
II.B. APPLICATION AND DURATION OF COVERAGE
- Application Required.
a. The owner and operator shall submit a complete and accurate on‐line application form with the appropriate fee to the MPCA for each project that disturbs one (1) or more acres of land or for a common plan of development or sale that will ultimately disturb one (1) or more acres. If the applicant is not able to apply on‐line, contact the MPCA for technical assistance or a waiver.
b. For certain projects or common plans of development or sale disturbing 50 acres or more, the application must be submitted at least 30 days before the start of construction activity. This requirement pertains to projects that have a discharge point on the project that is within one mile (aerial radius measurement) of, and flows to, a special water listed in Appendix A, Part B. or waters listed as impaired under section 303(d) of the federal Clean Water Act (see the MPCA’s website) where the identified pollutant(s) or stressor(s) are phosphorus (nutrient eutrophication biological indicators), turbidity, dissolved oxygen, or biotic impairment (fish bioassessment, aquatic plant bioassessment and aquatic macroinvertebrate bioassessment). Applicants of projects listed in this part must submit a complete and accurate application form and SWPPP including all calculations for the Permanent Stormwater Management System (see Parts III.A.‐D.).
- All persons meeting the definition of owner and operator are Permittees and must be listed on the application. The owner is responsible for compliance with all terms and conditions of this permit. The operator is responsible for compliance with Parts II.B, II.C, III.B‐F, IV, V, and applicable construction activity requirements found in Appendix A, Part C. of this permit and is jointly responsible with the owner for compliance with those portions of the permit.
- Permit Coverage Effective Date: The commencement of any construction activity (e.g., land disturbing activities) covered under Part I.A. of this permit is prohibited until permit coverage under this permit is effective.
a. For projects listed in Part II.B.1.a. permit coverage will become effective seven (7) calendar days after the electronic submittal date or the postmarked date of a complete application form.
b. For projects listed in Part II.B.1.b. permit coverage will become effective 30 calendar days after the electronic submittal date, the postmarked date or MPCA date stamp (whichever is first) of the complete application. For incomplete applications (e.g., lack of fees or signature) or incomplete SWPPPs (e.g., missing calculations, Best Management Practice (BMP) specifications, estimated quantities of the BMPs, or timing of BMP installation narrative), the permit becomes effective 30 calendar days after all required information is submitted.
- Coverage Notification: Permittee(s) will be notified of coverage in a manner as determined by the Commissioner (e.g., e‐mail, online notification or letter).
- Change of Coverage: For construction projects where the owner or operator changes, (e.g., an original developer sells portions of the property to various homebuilders or sells the entire site to a new owner) the current owner and the new owner or operator shall submit a complete permit modification on a form provided by the Commissioner. The form must be submitted prior to the new owner or operator commencing construction activity on site or in no case later than 30 days after taking ownership of the property. The owner shall provide a SWPPP to the new owner and operator that specifically addresses the remaining construction activity.
II.C. TERMINATION OF COVERAGE
- Termination of coverage when construction is complete: All Permittee(s) must submit a Notice of Termination (NOT) to the MPCA on a form provided by the Commissioner within 30 days after all activities required for Final Stabilization (see Part IV.G.) are complete. The Permittee(s)’ coverage under this permit terminates at midnight on the submission date of the NOT.
- Termination of coverage when transfer of ownership occurs: All Permittee(s) must submit a NOT on a form provided by the Commissioner within 30 days after selling or otherwise legally transferring the entire site, including permit responsibility for roads (e.g., street sweeping) and stormwater infrastructure final clean out, or transferring portions of a site to another party. The Permittee(s)’ coverage under this permit terminates at midnight on the submission date of the NOT.
- Permittee(s) may terminate permit coverage prior to completion of all construction activity if all of the following conditions are met. After the permit is terminated under this Part, if there is any subsequent development on the remaining portions of the site where construction activity was not complete, new permit coverage must be obtained 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.
a. Construction activity has ceased for at least 90 days.
b. At least 90 percent (by area) of all originally proposed construction activity has been completed and permanent cover established on those areas.
c. On areas where construction activity is not complete, permanent cover has been established.
d. The site is in compliance with Part IV.G.2. and Part IV.G.3. and where applicable, Part IV.G.4. or Part IV.G.5.
- Permittee(s) may terminate coverage upon approval by the MPCA if information is submitted to the MPCA documenting that termination is appropriate because the project is cancelled.
PART III. STORMWATER DISCHARGE DESIGN REQUIREMENTS
III.A. STORMWATER POLLUTION PREVENTION PLAN CONTENT
The owner must develop a Stormwater Pollution Prevention Plan (SWPPP). The SWPPP shall be completed prior to submitting any permit application and prior to conducting any construction activity by any required Permittee(s). For stormwater discharges from construction activity where the owner or operator changes, the new owner or operator can implement the original SWPPP created for the project, modify the original SWPPP, or develop and implement their own SWPPP. Permittee(s) shall ensure either directly or through coordination with other Permittee(s) that their SWPPP meets all terms and conditions of this permit and that their activities do not render another party’s erosion prevention and sediment control BMPs ineffective. The SWPPP must include the following:
- A description of the construction activity: The description must be a combination of narrative, plan sheets, and (if appropriate) standard detail sheets that address the foreseeable conditions, at any stage in the construction or post construction activities. The SWPPP must identify the potential for discharge of sediment and/or other potential pollutants from the site. The SWPPP must propose erosion prevention and sediment control BMPs to control the discharge of sediment and/or other potential pollutants from the site.
- Knowledgeable person/chain of responsibility: As part of the SWPPP, the owner must identify a person knowledgeable and experienced in the application of erosion prevention and sediment control BMPs who will oversee the implementation of the SWPPP, and the installation, inspection and maintenance of the erosion prevention and sediment control BMPs (see Part III.F.1.) before and during construction. The owner must identify in the SWPPP who will have the responsibility for long‐term operation and maintenance of the Permanent Stormwater Management System (see Part III.D.). The owner shall include in the SWPPP a chain of responsibility with all operators on the site, or if not known, the title or position of the responsible party, to ensure that the SWPPP will be implemented and stay in effect until the construction project is complete, the entire site has undergone Final Stabilization, and an NOT has been submitted to the MPCA. Once the identity of the responsible party is known, the SWPPP must be amended to inc lude this information.
- Training documentation: The Permittee(s) shall ensure the individuals identified in Part III.F. have been trained in accordance with this Permit’s training requirements. The Permittee(s) shall ensure the training is recorded in or with the SWPPP before the start of construction or as soon as the personnel for the project have been determined. Documentation shall include:
a. Names of the personnel associated with this project that are required to be trained per Part III.F.1. of this permit.
b. Dates of training and name of instructor(s) and entity providing training.
c. Content of training course or workshop including the number of hours of training.
- Designs, calculations, and narrative: The SWPPP must incorporate the requirements of Part III (Stormwater Discharge Design Requirements) including calculations, Part IV (Construction Activity Requirements) and Appendix A for the project. A narrative describing the timing for installation of all erosion prevention and sediment control BMPs and permanent stormwater management systems required in Part III, Appendix A must also be included in the SWPPP.
- SWPPP components: The SWPPP requirements must be incorporated into the project's final plans and specifications and/or project documentation, as appropriate, and must include:
a. Location and type of all temporary and permanent erosion prevention and sediment control BMPs along with procedures to be used to establish additional temporary BMPs as necessary for the site conditions during construction. Standard details and/or specifications for the BMPs used on the project must be included in the final plans and specifications for the project.
b. Quantities: Estimated preliminary quantities tabulation anticipated at the start of the project for the life of the project must be included for all erosion prevention and sediment control BMPs in the SWPPP (e.g., linear feet of silt fence or ft2 of erosion control blanket).
c. Impervious surface: The number of acres of impervious surface for both pre‐ and postconstruction must be specified.
d. Site map: A site map with existing and final grades, including dividing lines and direction of flow for all pre‐and post‐construction stormwater runoff drainage areas located within the project limits must be included. The site map must indicate the areas of steep slopes. The site map must also include impervious surfaces, soil types and locations of potential pollutant-generating activities as identified in Part IV.F.
e. Locations of areas not to be disturbed: Buffer zones, as required for temporary BMPs during construction in Part IV.C.9., or if required as permanent BMPs in Appendix A, Part C.3., must be described and identified on plan sheets or project maps in the SWPPP.
f. Construction phasing: Location of areas where construction will be phased to minimize duration of exposed soil areas must be described.
g. Maps of surface waters and wetlands: The SWPPP must include a map of all surface waters, existing wetlands, and stormwater ponds or basins which can be identified on maps such as United States Geological Survey 7.5 minute quadrangle maps, the National Wetland Inventory map or equivalent maps within one mile (aerial radius measurement) from the project boundaries that will receive stormwater from the construction site, during or after construction. Where surface waters receiving stormwater associated with construction activity will not fit on the plan sheet, they must be identified with an arrow, indicating both direction and distance to the surface water. The SWPPP must identify if the surface water is a special or impaired water. The site map must also show construction activity areas that are adjacent to and drain to Public Waters for which the Department of Natural Resources has promulgated “work in water restrictions” during specified fish spawning time frames.
h. Final stabilization: Methods to be used for Final Stabilization of all exposed soil areas must be described.
i. BMP design factors: The SWPPP must account for the following factors in designing the temporary erosion prevention and sediment control BMPs:
i. The expected amount, frequency, intensity, and duration of precipitation.
ii. 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.
iii. If any stormwater flow will be channelized at the site, the Permitte(s) must design BMPs to control both peak flowrates and total stormwater volume to minimize erosion at outlets and to minimize downstream channel and streambank erosion.
iv. The range of soil particle sizes expected to be present on the site.
j. Soil Management: Methods used to minimize soil compaction and preserve topsoil must be described. Minimizing soil compaction is not required where the function of a specific area of the site dictates that it be compacted.
k. Maintenance plan: For projects that include permanent stormwater treatment systems, the SWPPP must include a maintenance plan identifying who will be performing future maintenance of the system.
l. Chemical treatments: Any specific chemicals and the chemical treatment systems that may be used for enhancing the sedimentation process on the site, and how compliance will be achieved with the requirements in Part IV.C.10., must be described.
m. Documentation of infeasibility: If the Permittee(s) determine(s) that compliance with the requirement for temporary sediment basins (Part III.C.) is infeasible on the project site; the Permittee(s) must document that determination and the substitute BMPs in the SWPPP. If Permittee(s) cannot obtain right‐of‐way for the permanent stormwater management system; the Permittee(s) must document the infeasibility of obtaining right‐of‐way (Part III.D.)
- Stormwater pollution mitigation measures identified in environmental review or other required review: The SWPPP must include any stormwater mitigation measures approved as part of a final environmental review document, endangered species review, archeological or other required local, state or federal review conducted for the project. For the purposes of this permit provision, mitigation measures means actions necessary to avoid, minimize, or rectify (e.g., repairing, rehabilitating, restoring), reducing, eliminating or compensating for impacts related to: (1) stormwater discharges associated with the project’s construction activity; and (2) erosion prevention, sediment control and the Permanent Stormwater Management System for the project.
- Karst areas: The SWPPP must identify additional or different measures necessary (e.g. impervious liner in pond bottom) to assure compliance with surface and groundwater standards in Minn. R. chs. 7050 and 7060 in karst areas and to ensure protection of drinking water supply management areas (see Minn. R. 4720.5100, subp. 13).
- Impaired Waters and Total Maximum Daily Loads (TMDLs): The SWPPP must address the following:
a. For projects that have a discharge point on the project that is within one mile (aerial radius measurement) of and which flows to an impaired water, the Permittee(s) must identify the impaired water(s) in the SWPPP, and whether or not there is a USEPA‐approved TMDL for the pollutant(s) or stressor(s) identified in Appendix A, Part B.10. Unless otherwise notified by the MPCA in writing, the Permittee(s)’ identification of impaired waters must be based on the most recent USEPA approved section 303(d) Clean Water Act list of impaired waters and USEPA approved TMDLs at the time a complete permit application is submitted. The Permittee(s)’ identification must include those TMDLs, applicable to the project’s stormwater discharge, that were approved at any time prior to permit application submittal and are still in effect.
b. If the TMDL identifies specific implementation activities regarding construction stormwater that would apply to the site discharges, the Permittee(s) must include the BMPs identified in the TMDL and any other specific construction stormwater related implementation activities identified in the TMDL.
III.B. SWPPP AMENDMENTS
The Permittee(s) must amend the SWPPP as necessary to include additional requirements, such as additional or modified BMPs that are designed to correct problems identified or address situations whenever:
- There is a change in design, construction, operation, maintenance, weather or seasonal conditions that has a significant effect on the discharge of pollutants to surface waters or underground waters.
- Inspections or investigations by site owner or operators, USEPA or MPCA officials indicate the SWPPP is not effective in eliminating or significantly minimizing the discharge of pollutants to surface waters or underground waters or that the discharges are causing water quality standard exceedances (e.g., nuisance conditions as defined in Minn. R. 7050.0210, subp. 2).
- The SWPPP is not achieving the general objectives of minimizing pollutants in stormwater discharges associated with construction activity, or the SWPPP is not consistent with the terms and conditions of this permit.
- At any time after permit coverage is effective, the MPCA may determine that the project’s stormwater discharges may cause, have reasonable potential to cause, or contribute to non‐attainment of any applicable water quality standard, or that the SWPPP does not incorporate the applicable requirements in Part III.A.8., (Impaired Waters and TMDLs). If a water quality standard changes during the term of this permit, the MPCA will make a determination as to whether a modification of the SWPPP is necessary to address the new standard. If the MPCA makes such determination(s) or any of the determinations in Parts III.B.1.‐3., the MPCA will notify the Permittee(s) in writing. In response, the Permittee(s) must amend the SWPPP to address the identified concerns and submit information requested by the MPCA, which may include an individual permit application. If the MPCA’s written notification requires a response, failure to respond within the specified timeframe constitutes a permit violation.
III.C. TEMPORARY SEDIMENT BASINS
Where ten (10) or more acres of disturbed soil drain to a common location, the Permittee(s) must provide a temporary sediment basin to provide treatment to the runoff before it leaves the construction site or enters surface waters. A temporary sediment basin may be converted to a permanent basin after construction is complete. The temporary basin is no longer required when permanent cover has reduced the acreage of disturbed soil to less than ten (10) acres draining to a common location. The Permittee(s) is/are encouraged, but not required, to install temporary sediment basins where appropriate in areas with steep slopes or highly erodible soils even if less than ten (10) acres drains to one area. The basins must be designed and constructed according to the following requirements:
- The basins must provide live storage for a calculated volume of runoff from a two (2)‐year, 24‐hour storm from each acre drained to the basin, except that in no case shall the basin provide less than 1,800 cubic feet of live storage from each acre drained to the basin.
- Where the calculation in Part III.C.1. has not been performed, a temporary sediment basin providing 3,600 cubic feet of live storage per acre drained to the basin shall be provided for the entire drainage area of the temporary basin.
- Temporary basin outlets must be designed to prevent short‐circuiting and the discharge of floating debris. The basin must be designed with the ability to allow complete basin drawdown for maintenance activities, and must include a stabilized emergency overflow to prevent failure of pond integrity. The outlet structure must be designed to withdraw water from the surface in order to minimize the discharge of pollutants, except that the use of a surface withdrawal mechanism for discharge of the basin may be temporarily suspended during frozen conditions. Energy dissipation must be provided for the basin outlet (see Part IV.B.5.).
- Sediment Basins must be situated outside of surface waters and any buffer zone required under Appendix A.C.3, and must be designed to avoid draining water from wetlands unless the impact to the wetland is in compliance with the requirements of Appendix A, Part D.
- The temporary basins must be constructed and made operational prior to 10 or more acres of disturbed soil draining to a common location.
- Where a temporary sediment basin meeting the requirements of this part is infeasible, equivalent sediment controls such as smaller sediment basins, and/or sediment traps, silt fences, vegetative buffer strips, or any appropriate combination of measures are required for all down‐slope boundaries of the construction area and for side‐slope boundaries as dictated by individual site conditions. In determining whether installing a sediment basin is infeasible, the Permittee(s) must consider public safety and may consider factors such as site soils, slope, and available area on site. This determination of infeasibility must be documented in the SWPPP per Part III.A.5.m.
III.D. PERMANENT STORMWATER MANAGEMENT SYSTEM
The Permittee(s) shall design the project so that all stormwater discharged from the project during and after construction activities does not cause a violation of state water quality standards, including nuisance conditions, erosion in receiving channels or on downslope properties, or a significant adverse impact to wetlands caused by inundation or decrease of flow.
The Permittee(s) shall construct a permanent stormwater management system meeting the requirements of this Part, or 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.
Where a project’s ultimate development replaces vegetation and/or other pervious surfaces with one (1) or more acres of cumulative impervious surface, the Permittee(s) must design the project so that the water quality volume of one (1) inch of runoff from the new impervious surfaces created by the project is retained on site (i.e. infiltration or other volume reduction practices) and not discharged to a surface water. For purposes of this part, surface waters does not include man‐made drainage systems that convey stormwater to a compliant permanent stormwater management system.
For those projects where infiltration is prohibited (see Part III.D.1.j.), the Permittee(s) shall consider other methods of volume reduction and the water quality volume (or remainder of the water quality volume if some volume reduction is achieved) must be treated by a wet sedimentation basin, filtration system, regional ponding or equivalent methods prior to the discharge of stormwater to surface waters.
Where the proximity to bedrock precludes the installation of any of the permanent stormwater management practices outlined in Part III.D., other treatment, such as grassed swales, filtration systems, smaller ponds, or grit chambers, is required prior to the discharge of stormwater to surface waters.
For work on linear projects with lack of right‐of‐way where the Permittee(s) cannot obtain an easement or other permission for property needed to install treatment systems capable of treating the entire water quality volume on site, the Permittee(s) must maximize the water quality volume that can be treated prior to discharge to surface waters. Treatment can be provided through other methods or combination of methods such as grassed swales, filtration systems, smaller ponds, or grit chambers, prior to discharge to surface waters. A reasonable attempt must be made to obtain right‐of‐way during the project planning process. Documentation of these attempts must be in the SWPPP per Part III.A.5.m. in the section addressing infeasibility.
When constructing any of the permanent stormwater management systems in this part, the Permittee(s) must incorporate the following design parameters:
a. Infiltration/Filtration options include but are not limited to: infiltration basins, infiltration trenches, rainwater gardens, sand filters, organic filters, bioretention areas, natural or enhanced swales, dry storage ponds with underdrain discharge, off‐line retention areas, and natural depressions. Infiltration must be used only as appropriate to the site and land uses. The method selected by the Permittee(s) must remove settleable solids, floating materials, and oils and grease from the runoff to the maximum extent practicable before runoff enters the infiltration/filtration system. Filtration systems must be designed to remove at least 80 percent of total suspended solids. When designing the system the Permittee(s) must evaluate the impact of constructing an infiltration practice on existing hydrologic features (e.g., existing wetlands) and the system must be designed to maintain pre‐existing conditions (e.g., do not breach a perched water table that is supporting a wetland). For a discussion of potential stormwater hotspots, groundwater warnings, design measures, maintenance considerations or other retention, detention, and treatment devices, see the Minnesota Stormwater Manual found on the MPCA’s website.
b. Infiltration systems must not be excavated to final grade until the contributing drainage area has been constructed and fully stabilized unless rigorous erosion prevention and sediment controls are provided (Part III.D.1.c.).
c. When an infiltration system is excavated to final grade (or within three (3) feet of final grade), the Permittee(s) must employ rigorous erosion prevention and sediment controls (e.g., diversion berms) to keep sediment and runoff completely away from the infiltration area. The area must be staked off and marked so that heavy construction vehicles or equipment will not compact the soil in the proposed infiltration area.
d. To prevent clogging of the infiltration or filtration system, the Permittee(s) must use a pretreatment device such as a vegetated filter strip, small sedimentation basin, or water quality inlet (e.g., grit chamber) to settle particulates before the stormwater discharges into the infiltration or filtration system.
e. The Permittee(s) must design infiltration or filtration systems that provide a water quality volume (calculated as an instantaneous volume) of one (1) inch of runoff (or one (1) inch minus the volume of stormwater treated by another system on the site) from the new impervious surfaces created by the project.
f. The Permittee(s) must design the infiltration/filtration system to discharge the water quality volume routed to the system through the soil surface or filter media within 48 hours or less. dditional flows that cannot be infiltrated or filtered within 48 hours must be routed to bypass the system through a stabilized discharge point. The Permittee(s) must design the infiltration system to provide a means to visually verify that the system is discharging through the soil surface or filter media within 48 hours or less.
g. The Permittee(s) shall employ appropriate on‐site testing consistent with the recommendations found in the Minnesota Stormwater Manual to verify soil type and to ensure a minimum of three (3) feet of separation from the seasonally saturated soils (or from bedrock) and the bottom of the proposed infiltration/filtration system.
h. The Permittee(s) must ensure filtration systems with less than three (3) feet of separation from seasonally saturated soils or from bedrock are constructed with an impermeable liner.
i. The Permittee(s) must design adequate maintenance access (typically eight (8) feet wide).
j. Infiltration is prohibited when the infiltration system will be constructed in:
i. Areas that receive discharges from vehicle fueling and maintenance.
ii. Areas with less than three (3) feet of separation distance from the bottom of the infiltration system to the elevation of the seasonally saturated soils or the top of bedrock.
iii. Areas that receive discharges from industrial facilities which are not authorized to infiltrate industrial stormwater under an NPDES/SDS Industrial Stormwater Permit issued by the MPCA.
iv. Areas where high levels of contaminants in soil or groundwater will be mobilized by the infiltrating stormwater.
v. Areas of predominately Hydrologic Soil Group D (clay) soils unless allowed by a local unit of government with a current MS4 permit.
vi. Areas within 1,000 feet up‐gradient, or 100 feet down‐gradient of active karst features unless allowed by a local unit of government with a current MS4 permit.
vii. Areas within a Drinking Water Supply Management Area (DWSMA) as defined in Minn. R. 4720.5100, subp. 13., unless allowed by a local unit of government with a current MS4 permit.
viii. Areas where soil infiltration rates are more than 8.3 inches per hour unless soils are amended to slow the infiltration rate below 8.3 inches per hour or as allowed by a local unit of government with a current MS4 permit.
- Wet Sedimentation Basin
a. The Permitte(s) must design the basin to have a permanent volume of 1,800 cubic feet of storage below the outlet pipe for each acre that drains to the basin. The basin’s permanent volume must reach a minimum depth of at least three (3) feet and must have no depth greater than 10 feet. The basin must be configured such that scour or resuspension of solids is minimized.
b. The Permittee(s) must design basins to provide live storage for a water quality volume (calculated as an instantaneous volume) of one (1) inch of runoff (or one (1) inch minus the volume of stormwater treated by another system on the site) from the new impervious surfaces created by the project.
c. The Permittee(s) must design basin outlets such that the water quality volume is discharged at no more than 5.66 cubic feet per second (cfs) per acre of surface area of the pond.
d. The Permittee(s) must design basin outlets to prevent short‐circuiting and the discharge of floating debris. Basin outlets must have energy dissipation.
e. The Permittee(s) must design the basin to include a stabilized emergency overflow to accommodate storm events in excess of the basin’s hydraulic design.
f. The Permittee(s) must design adequate maintenance access (typically eight (8) feet wide).
g. The Permittee(s) must design sediment Basins to be situated outside of surface waters and any buffer zone required under Appendix A, Part C.3. and they must be designed to avoid draining water from wetlands unless the impact to the wetland is in compliance with the requirements of Appendix A, Part D.
- Regional Ponds
When the entire water quality volume cannot be retained onsite, the Permittee(s) can use or create regional ponds provided that they are constructed ponds, not a natural wetland or water body, (wetlands used as regional ponds must be mitigated for, see Appendix A, Part D) and designed in accordance with this permit’s design requirements (Part III.D.2.) for all water from impervious surfaces that reach the pond. Permittee(s) shall not construct regional ponds in wetlands, regardless of their condition, quality or designation by local plans, unless the mitigative sequence in Appendix A, Part D. of this permit has been completed. There must be no significant degradation of the waterways between the project and the regional pond. The owner must obtain written authorization from the applicable local governmental unit (LGU) or private entity that owns and maintains the regional pond. The LGU’s or private entity’s written authorization must identify that the regional pond will discharge the water q uality volume (one (1) inch of runoff from the impervious watershed area) at no more than 5.66 cfs per acre of surface area of the pond. The owner must include the LGU’s or private entities’ written authorization in the SWPPP. The LGU’s or private entity’s written authorization must be obtained before the owner finalizes the SWPPP and before any application for this permit is made to the MPCA.
III.E RECORD RETENTION
The SWPPP (original or copies) including, all changes to it, and inspections and maintenance records must be kept at the site during construction by the Permittee(s) who has/have operational control of that portion of the site. The SWPPP can be kept in either the field office or in an on‐site vehicle during normal working hours.
All owner(s) must keep the following records on file for three (3) years after submittal of the NOT as outlined in Part II.C. This does not include any records after submittal of the NOT.
- The final SWPPP
- Any other stormwater related permits required for the project
- Records of all inspection and maintenance conducted during construction (Part IV.E. Inspections and Maintenance)
- All permanent operation and maintenance agreements that have been implemented, including all right‐of‐way, contracts, covenants and other binding requirements regarding perpetual maintenance and
- All required calculations for design of the temporary and permanent Stormwater Management Systems.
III.F. TRAINING REQUIREMENTS
The Permittee(s) shall ensure the following individuals identified in this part have been trained in accordance with this Permit’s training requirements.
- Who must be trained:
a. Individual(s) preparing the SWPPP for the project
b. Individual(s) overseeing implementation of, revising, and amending the SWPPP and individual(s) performing inspections as required in Part IV.E. One of these individual(s) must be available for an onsite inspection within 72 hours upon request by the MPCA.
c. Individual(s) performing or supervising the installation, maintenance and repair of BMPs. At least one individual on a project must be trained in these job duties.
- Training content: The content and extent of training must be commensurate with the individual’s job duties and responsibilities with regard to activities covered under this permit for the project. At least one individual present on the permitted project site (or available to the project site in 72 hours) must be trained in the job duties described in Part III.F.1.b. and Part III.F.1.c.
- The Permittee(s) shall ensure that the individuals are trained by local, state, federal agencies, professional organizations, or other entities with expertise in erosion prevention, sediment control, permanent stormwater management and the Minnesota NPDES/SDS Construction Stormwater Permit. An update refresher‐training must be attended every three (3) years starting three (3) years from the issuance date of this permit.
PART IV. CONSTRUCTION ACTIVITY REQUIREMENTS
IV.A. STORMWATER POLLUTION PREVENTION PLAN
The Permittee(s) must implement the SWPPP and the requirements of this part. The BMPs identified in the SWPPP and in this permit must be selected, installed, and maintained in an appropriate and functional manner that is in accordance with relevant manufacturer specifications and accepted engineering practices.
IV.B. EROSION PREVENTION PRACTICES
- The Permittee(s) must plan for and implement appropriate BMPs such as construction phasing, vegetative buffer strips, horizontal slope grading, inspection and maintenance of Part IV.E. and other construction practices that minimize erosion as necessary to comply with this permit and protect waters of the state. The location of areas not to be disturbed must be delineated (e.g., with flags, stakes, signs, silt fence etc.) on the project site before work begins. The Permittee(s) must minimize the need for disturbance of portions of the project that have steep slopes. For those sloped areas which must be disturbed, the Permittee(s) must use techniques such as phasing and stabilization practices designed for steep slopes (e.g., slope draining and terracing).
- The Permittee(s) must stabilize all exposed soil areas (including stockpiles). Stabilization must be initiated immediately to limit soil erosion whenever any 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 in that portion of the site has temporarily or permanently ceased. For Public Waters that the Minnesota Department of Natural Resources has promulgated “work in water restrictions” during specified fish spawning time frames, all exposed soil areas that are within 200 feet of the water’s edge, and drain to these waters must complete the stabilization activities within 24 hours during the restriction period. Temporary stockpiles without significant silt, clay or organic components (e.g., clean aggregate stockpiles, demolition concrete stockpiles, sand stockpiles) and the constructed base components of roads, parking lots and similar surfaces are exempt from this requirement but must be in compliance with Part IV.C.5.
- If using stormwater conveyance channels ,the Permittee(s) must design the channels to route water around unstabilized areas on the site and to reduce erosion, unless infeasible. The Permittee(s) must use erosion controls and velocity dissipation devices such as check dams, sediment traps, riprap, or grouted riprap at outlets within and along the length of any constructed stormwater conveyance channel, and at any outlet, to provide a non‐erosive flow velocity, to minimize erosion of channels and their embankments, outlets, adjacent stream banks, slopes, and downstream waters during discharge conditions.
- The Permittee(s) must stabilize the normal wetted perimeter of any temporary or permanent drainage ditch or swale that drains water from any portion of the construction site, or diverts water around the site, within 200 lineal feet from the property edge, or from the point of discharge into any surface water. Stabilization of the last 200 lineal feet must be completed within 24 hours after connecting to a surface water or property edge.
The Permittee(s) shall complete stabilization of the remaining portions of any temporary or permanent ditches or swales within 14 calendar days after connecting to a surface water or property edge and construction in that portion of the ditch has temporarily or permanently ceased.
Temporary or permanent ditches or swales that are being used as a sediment containment system during construction (with properly designed rock‐ditch checks, bio rolls, silt dikes, etc.) do not need to be stabilized during the temporary period of its use as a sediment containment system. These areas must be stabilized within 24 hours after no longer being used as a sediment containment system.
Applying mulch, hydromulch, tackifier, polyacrylamide or similar erosion prevention practices is not acceptable stabilization in any part of a temporary or permanent drainage ditch or swale.
- Pipe outlets must be provided with temporary or permanent energy dissipation within 24 hours after connection to a surface water.
- Unless infeasible due to lack of pervious or vegetated areas, the Permittee(s) must direct discharges from BMPs to vegetated areas of the site (including any natural buffers) in order to increase sediment removal and maximize stormwater infiltration. The Permittee(s) must use velocity dissipation devices if necessary to prevent erosion when directing stormwater to vegetated areas.
IV.C. SEDIMENT CONTROL PRACTICES
- The Permittee(s) must employ Sediment control practices as necessary to minimize sediment from entering surface waters, including curb and gutter systems and storm sewer inlets.
a. Temporary or permanent drainage ditches and sediment basins that are designed as part of a sediment containment system (e.g., ditches with rock‐check dams) require sediment control practices only as appropriate for site conditions.
b. If the down gradient sediment controls are overloaded (based on frequent failure or excessive maintenance requirement), the Permittee(s) must install additional upgradient sediment control practices or redundant BMPs to eliminate the overloading, and the SWPPP must be amended to identify these additional practices as required in Part III.B 1.‐3.
- Sediment control practices must be established on all down gradient perimeters and be located upgradient of any buffer zones. The perimeter sediment control practice must be in place before any upgradient land‐disturbing activities begin. These practices shall remain in place until Final Stabilization has been established in accordance with Part IV.G. A floating silt curtain placed in the water is not a sediment control BMP to satisfy perimeter control requirements in this part except when working on a shoreline and below the waterline. In those cases, a floating silt curtain can be used as a perimeter control practice if the floating silt curtain is installed as close to shore as possible. Immediately after the short term construction activity (e.g. installation of rip rap along the shoreline) in that area is complete, an upland perimeter control practice must be installed if exposed soils still drain to the surface water.
- The Permittee(s) shall re‐install all sediment control practices that have been adjusted or removed to accommodate short‐term activities such as clearing or grubbing, or passage of vehicles, immediately after the short‐term activity has been completed. The Permittee(s) shall complete any short‐term activity that requires removal of sediment control practices as quickly as possible. The Permittee(s) must re‐install sediment control practices before the next precipitation event even if the short‐term activity is not complete.
- All storm drain inlets must be protected by appropriate BMPs during construction until all sources with potential for discharging to the inlet have been stabilized. Inlet protection may be removed for a particular inlet if a specific safety concern (street flooding/freezing) has been identified by the Permittee(s) or the jurisdictional authority (e.g., city/county/township/MnDOT engineer).The Permittee(s) must document the need for removal in the SWPPP.
- Temporary soil stockpiles must have silt fence or other effective sediment controls, and cannot be placed in any natural buffers or surface waters, including stormwater conveyances such as curb and gutter systems, or conduits and ditches unless there is a bypass in place for the stormwater.
- Where vehicle traffic leaves any part of the site (or onto paved roads within the site):
a. The Permittee(s) must install a vehicle tracking BMP to minimize the track out of sediment from the construction site. Examples of vehicle tracking BMPs include (but are not limited to) rock pads, mud mats, slash mulch, concrete or steel wash racks, or equivalent systems.
b. The Permittee(s) must use street sweeping if such vehicle tracking BMPs are not adequate to prevent sediment from being tracked onto the street (see Part IV.E.5.d.).
- The Permittee(s) must install temporary sedimentation basins as required in Part III.C. of this permit.
- The Permittee(s) must minimize soil compaction and, unless infeasible, preserve topsoil. Minimizing soil compaction is not required where the function of a specific area of the site dictates that it be compacted.
- The Permittee(s) must preserve a 50 foot natural buffer or (if a buffer is infeasible on the site) provide redundant sediment controls when a surface water is located within 50 feet of the project’s earth disturbances and stormwater flows to the surface water. Natural buffers are not required adjacent to road ditches, judicial ditches, county ditches, stormwater conveyance channels, storm drain inlets, and sediment basins. The Permittee(s) is/are not required to enhance the quality of the vegetation that already exists in the buffer or provide vegetation if none exist. However, Permittee(s) can improve the natural buffer with vegetation.
- If the Permittee(s) intend to use polymers, flocculants, or other sedimentation treatment chemicals on the project site, the Permittee(s) must comply with the following minimum requirements:
a. The Permittee(s) must use conventional erosion and sediment controls prior to chemical addition to ensure effective treatment. Chemicals may only be applied where treated stormwater is directed to a sediment control system which allows for filtration or settlement of the floc prior to discharge.
b. Chemicals must be selected that are appropriately suited to the types of soils likely to be exposed during construction, and to the expected turbidity, pH, and flow rate of stormwater flowing into the chemical treatment system or area.
c. Chemicals must be used in accordance with accepted engineering practices, and with dosing specifications and sediment removal design specifications provided by the manufacturer or provider/supplier of the applicable chemicals.
IV.D. DEWATERING AND BASIN DRAINING
- The Permittee(s) 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. The Permittee(s) may discharge from the temporary or permanent sedimentation basins to surface waters if the basin water has been visually checked to ensure adequate treatment has been obtained in the basin and that nuisance conditions (see Minn. R. 7050.0210, subp. 2) will not result from the discharge. If the water cannot be discharged to a sedimentation basin prior to entering the surface water, it must be treated with the appropriate BMPs, such that the discharge does not adversely affect the receiving water or downstream properties. If the Permittee(s) must discharge water that contains oil or grease, the Permittee(s) must use an oil‐water separator or suitable filtration device (e.g. cartridge filters, absorbents pads) prior to discharging the water. The Permittee(s) must ensure that discharge points are adequately protected from erosion and scour. The discharge must be dispersed over natural rock riprap, sand bags, plastic sheeting, or other accepted energy dissipation measures.
- All water from dewatering or basin‐draining activities must be discharged in a manner that does not cause nuisance conditions, erosion in receiving channels or on downslope properties, or inundation in wetlands causing significant adverse impact to the wetland.
- If the Permittee(s) is/are using filters with backwash water, the Permittee(s) 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. The Permittee(s) may discharge backwash water to the sanitary sewer if permission is granted by the sanitary sewer authority. The Permittee(s) must replace and clean the filter media used in dewatering devices when required to retain adequate function.
IV.E. INSPECTIONS AND MAINTENANCE
- The Permittee(s) must ensure that a trained person (as identified in Part III.A.3.a.) will routinely 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 0.5 inches in 24 hours. Following an inspection that occurs within 24 hours after a rainfall event, the next inspection must be conducted within seven (7) days after the rainfall event.
- All inspections and maintenance conducted during construction must be recorded within 24 hours in writing and these records must be retained with the SWPPP in accordance with Part III.E. Records of each inspection and maintenance activity shall include:
a. Date and time of inspections
b. Name of person(s) conducting inspections
c. Findings of inspections, including the specific location where corrective actions are needed
d. Corrective actions taken (including dates, times, and party completing maintenance activities)
e. Date and amount of all rainfall events greater than 1/2 inch (0.5 inches) in 24 hours. Rainfall amounts must be obtained by a properly maintained rain gauge installed onsite, a weather station that is within 1 mile of your location or a weather reporting system that provides site specific rainfall data from radar summaries.
f. If any discharge is observed to be occurring during the inspection, a record of all points of the property from which there is a discha rge must be made, and the discharge should be described (i.e., color, odor, floating, settled, or suspended solids, foam, oil sheen, and other obvious indicators of pollutants) and photographed.
g. Any amendments to the SWPPP proposed as a result of the inspection must be documented as required in Part III.B. within seven (7) calendar days.
- Inspection frequency adjustment
a. Where parts of the project site have permanent cover, but work remains on other parts of the site, the Permittee(s) may reduce inspections of the areas with permanent cover to once per month.
b. Where construction sites have permanent cover on all exposed soil areas and no construction activity is occurring anywhere on the site, the site must be inspected during non‐frozen ground conditions at least once per month for a period of twelve (12) months. Following the twelfth month of permanent cover and no construction activity, inspections may be terminated until construction activity is once again initiated unless the Permittee(s) is/are notified in writing by the MPCA that erosion issues have been detected at the site and inspections need to resume.
c. Where work has been suspended due to frozen ground conditions, the inspections may be suspended. The required inspections and maintenance schedule must begin within 24 hours after runoff occurs at the site or 24 hours prior to resuming construction, whichever comes first.
- The Permittee(s) is/are responsible for the inspection and maintenance of temporary and permanent water quality management BMPs, as well as all erosion prevention and sediment control BMPs, until another Permittee has obtained coverage under this Permit according to Part II.B.5. or the project has undergone Final Stabilization, and an NOT has been submitted to the MPCA.
- The Permittee(s) must inspect all erosion prevention and sediment control BMPs and Pollution Prevention Management Measures to ensure integrity and effectiveness during all routine and post‐rainfall event inspections. All nonfunctional BMPs must be repaired, replaced, or supplemented with functional BMPs by the end of the next business day after discovery, or as soon as field conditions allow access unless another time frame is specified below. The Permittee(s) must investigate and comply with the following inspection and maintenance requirements:
a. All perimeter control devices must be repaired, replaced, or supplemented when they become nonfunctional or the sediment reaches one‐half (1/2) of the height of the device. These repairs must be made by the end of the next business day after discovery, or thereafter as soon as field conditions allow access.
b. Temporary and permanent sedimentation basins must be drained and the sediment removed when the depth of sediment collected in the basin reaches one‐half (1/2) the storage volume. Drainage and removal must be completed within 72 hours of discovery, or as soon as field conditions allow access (see Part IV.D.).
c. Surface waters, including drainage ditches and conveyance systems, must be inspected for evidence of erosion and sediment deposition during each inspection. The Permittee(s) must remove all deltas and sediment deposited in surface waters, including drainage ways, catch basins, and other drainage systems, and restabilize the areas where sediment removal results in exposed soil. The removal and stabilization must take place within seven (7) days of discovery unless precluded by legal, regulatory, or physical access constraints. The Permittee(s) shall use all reasonable efforts to obtain access. If precluded, removal and stabilization must take place within seven (7) calendar days of obtaining access. The Permittee(s) is/are responsible for contacting all local, regional, state and federal authorities and receiving any applicable permits, prior to conducting any work in surface waters.
d. Construction site vehicle exit locations must be inspected for evidence of off‐site sediment tracking onto paved surfaces. Tracked sediment must be removed from all paved surfaces both on and off site within 24 hours of discovery, or if applicable, within a shorter time to comply with Part IV.C.6.
e. Streets and other areas adjacent to the project must be inspected for evidence of off‐site accumulations of sediment. If sediment is present, it must be removed in a manner and at a frequency sufficient to minimize off‐site impacts (e.g., fugitive sediment in streets could be washed into storm sewers by the next rain and/or pose a safety hazard to users of public streets).
- All infiltration areas must be inspected to ensure that no sediment from ongoing construction activity is reaching the infiltration area. All infiltration areas must be inspected to ensure that equipment is not being driven across the infiltration area.
IV.F. POLLUTION PREVENTION MANAGEMENT MEASURES
The Permittee(s) shall implement the following pollution prevention management measures on the site:
- Storage, Handling, and Disposal of Construction Products, Materials, and Wastes: The Permittee(s) shall comply with the following to minimize the exposure to stormwater of any of the products, materials, or wastes. Products or wastes which are either not a source of contamination to stormwater or are designed to be exposed to stormwater are not held to this requirement:
a. Building products that have the potential to leach pollutants must be under cover (e.g., plastic sheeting or temporary roofs) to prevent the discharge of pollutants or protected by a similarly effective means designed to minimize contact with stormwater.
b. Pesticides, herbicides, insecticides, fertilizers, treatment chemicals, and landscape materials must be under cover (e.g., plastic sheeting or temporary roofs) to prevent the discharge of pollutants or protected by similarly effective means designed to minimize contact with stormwater.
c. Hazardous materials, toxic waste, (including oil, diesel fuel, gasoline, hydraulic fluids, paint solvents, petroleum‐based products, wood preservatives, additives, curing compounds, and acids) must be properly stored in sealed containers to prevent spills, leaks or other discharge. Restricted access storage areas must be provided to prevent vandalism. Storage and disposal of hazardous waste or hazardous materials must be in compliance with Minn. R. ch. 7045 including secondary containment as applicable.
d. Solid waste must be stored, collected and disposed of properly in compliance with Minn. R. ch. 7035.
e. Portable toilets must be positioned so that they are secure and will not be tipped or knocked over. Sanitary waste must be disposed of properly in accordance with Minn. R. ch. 7041.
- Fueling and Maintenance of Equipment or Vehicles; Spill Prevention and Response: The Permittee(s) shall take reasonable steps to prevent the discharge of spilled or leaked chemicals, including fuel, from any area where chemicals or fuel will be loaded or unloaded including the use of drip pans or absorbents unless infeasible. The Permittee(s) must conduct fueling in a contained area unless infeasible. The Permittee(s) must ensure adequate supplies are available at all times to clean up discharged materials and that an appropriate disposal method is available for recovered spilled materials. The Permittee(s) must report and clean up spills immediately as required by Minn. Stat. § 115.061, using dry clean up measures where possible.
- Vehicle and equipment washing: If the Permittee(s) wash the exterior of vehicles or equipment on the project site, washing must be limited to a defined area of the site. Runoff from the washing area must be contained in a sediment basin or other similarly effective controls and waste from the washing activity must be properly disposed of. The Permittee(s) must properly use and store soaps, detergents, or solvents. No engine degreasing is allowed on site.
- Concrete and other washouts waste: The Permittee(s) must provide effective containment for all liquid and solid wastes generated by washout operations (concrete, stucco, paint, form release oils, curing compounds and other construction materials) related to the construction activity. The liquid and solid washout wastes must not contact the ground, and the containment must be designed so that it does not result in runoff from the washout operations or areas. Liquid and solid wastes must be disposed of properly and in compliance with MPCA rules. A sign must be installed adjacent to each washout facility that requires site personnel to utilize the proper facilities for disposal of concrete and other washout wastes.
IV.G. FINAL STABILIZATION
The Permittee(s) must ensure Final Stabilization of the site. Final Stabilization is not complete until all requirements of Parts IV.G.1‐5. are complete:
- All soil disturbing activities at the site have been completed and all soils are stabilized by a uniform perennial vegetative cover with a density of 70 percent of its expected final growth density over the entire pervious surface area, or other equivalent means necessary to prevent soil failure under erosive conditions.
- The permanent stormwater management system is constructed, meets all requirements in Part III.D. and is operating as designed. Temporary or permanent sedimentation basins that are to be used as permanent water quality management basins have been cleaned of any accumulated sediment. All sediment has been removed from conveyance systems and ditches are stabilized with permanent cover.
- All temporary synthetic and structural erosion prevention and sediment control BMPs (such as silt fence) have been removed on the portions of the site for which the Permittee(s) is/are responsible. BMPs designed to decompose on site (such as some compost logs) may be left in place.
- For residential construction only, individual lots are considered finally stabilized if the structure(s) are finished and temporary erosion protection and downgradient perimeter control has been completed and the residence has been sold to the homeowner. Additionally, the Permittee has distributed the MPCA’s “Homeowner Fact Sheet” to the homeowner to inform the homeowner of the need for, and benefits of, permanent cover.
- For construction projects on agricultural land (e.g., pipelines across crop, field pasture or range land) the disturbed land has been returned to its preconstruction agricultural use.
PART V. GENERAL PROVISIONS
V.A. APPLICABILITY CRITERIA
- If the Commissioner determines that pollution in stormwater discharges associated with a construction activity are contributing to a violation of a water quality standard or due to specific site considerations rendering a substantial portion of the requirements of this permit impossible to comply with, and the Commissioner determines that the construction activity would be more appropriately regulated by an individual permit, the Commissioner may terminate coverage under this general permit and require the owner and operator to continue the construction activity subject to an individual stormwater discharge permit. Upon issuance of an individual permit, this general permit would no longer apply. Prior to termination of coverage under this general permit, the Commissioner will provide notice and an opportunity to request a contested case hearing.
- If the terms and conditions of this general permit cannot be met, an owner may request an individual permit, in accordance with Minn. R. 7001.0210 subp. 6.
- Any interested person may petition the MPCA to require an individual NPDES/SDS permit in accordance with CFR 122.28(b)(3).
V.B. RECORD AVAILABILITY
- The Permittee(s) must make the SWPPP, including all certificates, reports, records, or other information required by this permit, available to federal, state, and local officials within 72 hours upon request for the duration of the permit and for three (3) years following the NOT. This does not include any records after submittal of the NOT.
- When requested by the MPCA, the Permittee(s) must make the responsible person trained as required in Part III.F.1.b. or Part III.F.1.c. available to be onsite during an MPCA inspection within 72 hours of a request.
This permit prohibits discharges of any material other than stormwater treated in compliance with this permit and discharges from dewatering or basin draining activities in accordance with Part IV.D.1.‐2. Prohibited discharges include (but are not limited to) wastewater from washout of concrete, stucco, paint, form release oils, curing compounds and other construction materials, fuels, oils, or other pollutants used in vehicle and equipment operation and maintenance, soaps or solvents used in vehicle and equipment washing and maintenance, and other hazardous substances or wastes.
V.D. TRANSFER OF OWNERSHIP OR CONTROL
This permit may not be assigned or transferred by the Permittee(s) except when transfer occurs in accordance with the applicable requirements of Part II.B.5.
V.E. CIVIL AND CRIMINAL LIABILITY
Nothing in this permit must be construed to relieve the Permittee(s) from civil or criminal penalties for noncompliance with the terms and conditions provided herein. Nothing in this permit must be construed to preclude the initiation of any legal action or relieve the Permittee(s) from any responsibilities, liabilities, or penalties to which the Permittee(s) is/are or may be subject to under Section 311 of the Clean Water Act and Minn. Stat. § 115 and 116, as amended. The Permittee(s) is/are not liable for permit requirements for activities occurring on those portions of a site where the permit has been transferred to another party as required in Part II.B.5. or the Permittee(s) has/have submitted the NOT as required in Part II.C.
The provisions of this permit are severable. If any provision of this permit, or the application of any provision of this permit to any circumstances, is held invalid, the application of such provision to other circumstances, and the remainder of this permit must not be affected thereby.
V.G. NPDES/SDS RULE STANDARD GENERAL CONDITIONS
The Permittee(s) must comply with the provisions of Minn. R. 7001.0150, subp. 3 and Minn. R. 7001.1090, subp. 1(A), 1(B), 1(C), 1(H), 1(I), 1(J), 1(K), and 1(L).
V.H. INSPECTION AND ENTRY
The Permittee(s) must allow access as provided in 40 CFR 122.41(i) and Minn. Stat. § 115.04. The Permittee(s) shall allow representatives of the MPCA or any member, employee or agent thereof, when authorized by it, upon presentation of credentials, to enter upon any property, public or private, for the purpose of obtaining information or examination of records or conducting surveys or investigations.
A. GENERAL REQUIREMENTS
All requirements in this Appendix are in addition to BMPs already specified in the permit. Where provisions of Appendix A, conflict with requirements elsewhere in the permit, the provisions in Appendix A take precedence. All BMPs used to comply with this Appendix must be documented in the SWPPP for the project. If the terms and conditions of this Appendix cannot be met, an individual permit will be required in accordance with Minn. R. ch. 7001.
B. REQUIREMENTS FOR DISCHARGES TO SPECIAL WATERS AND IMPAIRED WATERS
Additional BMPs and enhanced runoff controls identified in this Part are required for discharges to the following special waters (Part B.1 through B.9 of Appendix A) and impaired waters (Part B.10 of Appendix A). The BMPs identified for each special or impaired water are required for those areas of the project draining to a discharge point on the project that is within one mile (aerial radius measurement) of a special or impaired water and flows to that special or impaired water.
- Wilderness areas: Boundary Waters Canoe Area Wilderness; Voyageurs National Park; Kettle River from the site of the former dam at Sandstone to its confluence with the Saint Croix River; Rum River from Ogechie Lake spillway to the northernmost confluence with Lake Onamia. Discharges to these waters must incorporate the BMPs outlined in C.1, C.2, and C.3 of this Appendix.
- Mississippi River: Those portions from Lake Itasca to the southerly boundary of Morrison County that are included in the Mississippi Headwaters Board comprehensive plan dated February 12, 1981. Discharges to these waters must incorporate the BMPs outlined in C.1, C.2 and C.3 of this Appendix.
- Scenic or recreational river segments: Saint Croix River, entire length; Cannon River from northern city limits of Faribault to its confluence with the Mississippi River; North Fork of the Crow River from Lake Koronis outlet to the Meeker-Wright county line; Kettle River from north Pine County line to the site of the former dam at Sandstone; Minnesota River from Lac qui Parle dam to Redwood County State Aid Highway 11; Mississippi River from County State Aid Highway 7 bridge in Saint Cloud to northwestern city limits of Anoka; and Rum River from State Highway 27 bridge in Onamia to Madison and Rice streets in Anoka. Discharges to these waters must incorporate the BMPs outlined in C.1, C.2 and C.3 of this Appendix.
- Lake Superior: (Prohibited and restricted) Discharges to Lake Superior must incorporate the BMPs outlined in C.1, C.2 and C.3 of this Appendix.
- Lake Trout Lakes: Identified in Minn. R. 7050.0470, including those inside the boundaries of the Boundary Waters Canoe Area Wilderness and Voyageurs National Park. Discharges to these waters must incorporate the BMPs outlined in C.1, C.2, and C.3 of this Appendix.
- Trout Lakes: Identified in Minn. R. 6264.0050, subp. 2. Discharges to these waters must incorporate the BMPs outlined in C.1, C.2, and C.3, of this Appendix.
- Scientific and natural areas: Boot Lake, Anoka County; Kettle River in sections 15, 22, 23, T 41 N, R 20, Pine County; Pennington Bog, Beltrami County; Purvis Lake-Ober Foundation, Saint Louis County; waters within the borders of Itasca Wilderness Sanctuary, Clearwater County; Iron Springs Bog, Clearwater County; Wolsfeld Woods, Hennepin County; Green Water Lake, Becker County; Blackdog Preserve, Dakota County; Prairie Bush Clover, Jackson County; Black Lake Bog, Pine County; Pembina Trail Preserve, Polk County; and Falls Creek, Washington County. Discharges to these waters must incorporate the BMPs outlined in C.1, C.2, and C.3 of this Appendix.
- Trout Streams: Listed in Minn. R. 6264.0050, subp. 4. Discharges to these waters must incorporate the BMPs outlined in C.1, C.2, C.3, and C.4 of this Appendix.
- Calcareous Fens: Listed in Minn. R 7050.0180 subp.6b. Discharges to these Calcareous Fens must incorporate the BMPs outlined in C.1 and C.2 of this Appendix.
- Impaired Waters: Waters identified as impaired under section 303 (d) of the federal Clean Water Act for phosphorus (nutrient eutrophication biological indicators), turbidity, dissolved oxygen or aquatic biota (fish bioassessment, aquatic plant bioassessment and aquatic macroinvertebrate bioassessment).
a. Impaired Water Without an Approved TMDL or With an Approved TMDL and No Waste Load Allocation:
If runoff from the site discharges to an impaired water, and a TMDL has not been approved by USEPA or there is a USEPA approved TMDL that does not establish a Waste Load Allocation (WLA) for construction stormwater, discharges to these waters must incorporate the BMPs outlined in C.1 and C.2 of this Appendix.
b. Impaired Water With an Approved TMDL and WLA:
If runoff from the site discharges to an impaired water for which there is a USEPA approved TMDL that establishes a WLA for construction stormwater, and the TMDL does not identify any specific implementation activities that would apply to the site discharges, discharges to these waters must incorporate the BMPs outlined in C.1 and C.2 of this Appendix.
If the TMDL identifies specific implementation activities regarding construction stormwater that would apply to the site discharges, the Permittee(s) must include the following in the SWPPP:
i. Identify the receiving water, the areas of the site discharging to it, and the pollutant(s) identified in the TMDL and
ii. BMPs identified in the TMDL and any other specific construction stormwater related implementation activities identified in the TMDL.
Note on impaired waters listing terminology: The terms in parenthesis in Appendix A Part B.10 above are the most current terminology used to list waters as impaired at the time of permit issuance. These terms are subject to change. For example, at one time waters were listed as impaired for phosphorus and now those same waters are listed as impaired for nutrient eutrophication biological indicators. If the terminology changes for one of the pollutant(s) or stressor(s) identified in the permit, the MPCA will keep a list of the new terms on its construction stormwater website.
C. ADDITIONAL BMPS FOR SPECIAL WATERS AND IMPAIRED WATERS
- For the BMPs described in C.2, and C.4 of this Appendix:
- Where the proximity to bedrock precludes the installation of any of the permanent stormwater management practices outlined in Appendix A, other treatment (such as grassed swales, smaller ponds, or grit chambers) is required prior to discharge to surface waters.
- For work on linear projects where the Permittee(s) cannot obtain an easement or other permission for property needed to install treatment systems capable of treating the entire water quality volume on site, smaller ponds or grit chambers are required prior to discharge to surface waters. A reasonable attempt must be made to obtain right-of-way during the project planning process. Documentation of these attempts must be in the SWPPP for the project.
- 1. During construction:
- a. Stabilization of all exposed soil areas must be initiated immediately to limit soil erosion but in no case completed later than seven (7) days after the construction activity in that portion of the site has temporarily or permanently ceased.
- b. Temporary sediment basin requirements described in Part III.C. must be used for common drainage locations that serve an area with five (5) or more acres disturbed at one time.
- 2. Post construction: The water quality volume that must be retained on site by the project’s permanent stormwater management system described in Part III.D. shall be one (1) inch of runoff from the new impervious surfaces created by the project. See Part III.D.1. for more information on infiltration design, prohibitions and appropriate site conditions. If it is determined that infiltration is not feasible due to site conditions (e.g., lack of three (3) feet of separation to seasonally saturated groundwater, proximity to bedrock, contaminated soils) the reasons should be documented in the SWPPP for the project .
- 3. Buffer zone: The Permittee(s) shall include an undisturbed buffer zone of not less than 100 linear feet from the special water (not including tributaries) and this buffer zone shall be maintained at all times, both during construction and as a permanent feature post construction, except where a water crossing or other encroachment is necessary to complete the project. The Permittee(s) must fully document the circumstance and reasons that the buffer encroachment is necessary in the SWPPP and include restoration activities. Replacement of existing impervious surface within the buffer is allowed under this permit. All potential water quality, scenic and other environmental impacts of these exceptions must be minimized by the use of additional or redundant BMPs and documented in the SWPPP for the project.
- 4. Temperature Controls: The Permittee(s) must design the Permanent Stormwater Management System such that the discharge from the project will minimize any increase in the temperature of trout stream receiving waters resulting from the one (1)-and two (2)-year 24-hour precipitation events. This includes all tributaries of designated trout streams within the Public Land Survey System (PLSS) Section that the trout stream is located. Projects that discharge to trout streams must minimize the impact using one or more of the following measures, in order of preference:
- a. Minimize new impervious surfaces.
- b. Minimize the discharge from connected impervious surfaces by discharging to vegetated areas, or grass swales, and through the use of other non-structural controls.
- c. Infiltration or other volume reduction practices evapotranspiration of to reduce runoff in excess of pre-project conditions (up to the two (2)-year 24-hour precipitation event).
- d. If ponding is used, the design must include an appropriate combination of measures such as shading, filtered bottom withdrawal, vegetated swale discharges or constructed wetland treatment cells that will limit temperature increases. The pond should be designed to draw down in 24 hours or less.
- e. Other methods that will minimize any increase in the temperature of the trout stream.
D. REQUIREMENTS FOR DISCHARGING TO WETLANDS
If the project has any discharges with the potential for significant adverse impacts to a wetland, (e.g., conversion of a natural wetland to a stormwater pond) the Permittee(s) must demonstrate that the wetland mitigative sequence has been followed in accordance with D.1 or D.2 of this Appendix.
- If the potential adverse impacts to a wetland on a specific project site have been addressed by permits or other approvals from an official statewide program (U.S. Army Corps of Engineers 404 program, Minnesota DNR, or the State of Minnesota Wetland Conservation Act) that are issued specifically for the project and project site, the Permittee may use the permit or other determination issued by these agencies to show that the potential adverse impacts have been addressed. For the purposes of this permit, deminimus actions are determinations by the permitting agency that address the project impacts, whereas a non-jurisdictional determination does not address project impacts.
- If there are impacts from the project that are not addressed in one of the permits or other determinations discussed in Appendix A, Part D.1 (e.g., permanent inundation or flooding of the wetland, significant degradation of water quality, excavation, filling, draining), the Permittee must minimize all adverse impacts to wetlands by utilizing appropriate measures. Measures used must be based on the nature of the wetland, its vegetative community types and the established hydrology. These measures include in order of preference:
a. Avoid all significant adverse impacts to wetlands from the project and post-project discharge.
b. Minimize any unavoidable impacts from the project and post-project discharge.
c. Provide compensatory mitigation when the Permittee determines that there is no reasonable and practicable alternative to having a significant adverse impact on a wetland. For compensatory mitigation, wetland restoration or creation shall be of the same type, size and whenever reasonable and practicable in the same watershed as the impacted wetland.
E. DISCHARGES REQUIRING ENVIRONMENTAL REVIEW
This permit does not replace or satisfy any environmental review requirements, including those under the Minnesota Environmental Policy Act or the National Environmental Policy Act. The owner must verify that any environmental review required by law, including any required Environmental Assessment Work sheets or Environmental Impact Statements, Federal environmental review, or other required review is complete before making application for coverage under this permit, and the owner must incorporate any stormwater mitigation measures required as the result of any environmental review into the SWPPP for the project. If any part of your common plan of development or sale requires environmental review, coverage under this permit cannot be obtained until such environmental review is complete.
F. DISCHARGES AFFECTING ENDANGERED OR THREATENED SPECIES
This permit does not replace or satisfy any review requirements for endangered or threatened species, from new or expanded discharges that adversely impact or contribute to adverse impacts on a listed endangered or threatened species, or adversely modify a designated critical habitat. The owner must conduct any required review and coordinate with appropriate agencies for any project with the potential of affecting threatened or endangered species, or their critical habitat.
G. DISCHARGES AFFECTING HISTORIC PLACES OR ARCHEOLOGICAL SITES
This permit does not replace or satisfy any review requirements for historic places or archeological sites, from new or expanded discharges that adversely affect properties listed or eligible for listing in the National Register of Historic Places or affecting known or discovered archeological sites. The owner must be in compliance with National Historic Preservation Act and conduct all required review and coordination related to historic preservation, including significant anthropological sites and any burial sites, with the Minnesota Historic Preservation Officer.
APPENDIX B. – DEFINITIONS
- “Aerial radius measurement” means the shortest straight line distance measurement between the point of stormwater discharge from a project construction site to the nearest edge of the water body the stormwater will flow to. This measurement does not follow the meander flow path.
- “Best Management Practices (BMPs)” means the most effective and practicable means of erosion prevention and sediment control, and water quality management practices that are the most effective and practicable means of to control, prevent, and minimize degradation of surface water, including avoidance of impacts, construction-phasing, minimizing the length of time soil areas are exposed, prohibitions, and other management practices published by state or designated area-wide planning agencies.
- Individual BMPs found in this permit are described in the current versions of Protecting Water Quality in Urban Areas, MPCA and The Minnesota Stormwater Manual, MPCA. BMPs must be adapted to the site and can be adopted from other sources. However, they must be similar in purpose and at least as effective and stringent as MPCA’s BMPs. (Other sources include manufacturers specifications, Storm Water Management for Construction Activities: Developing Pollution Prevention Plans and Best Management Practices, U.S. Environmental Protection Agency 1992, and Erosion Control Design Manual, Minnesota Department of Transportation, et al, 1993).
- “Commissioner” means the Commissioner of the MPCA or the Commissioner's designee.
- “Common Plan of Development or Sale” means a contiguous area where multiple separate and distinct land-disturbing activities may be taking place at different times, on different schedules, but under one proposed plan. One plan is broadly defined to include design, permit application, advertisement or physical demarcation indicating that land-disturbing activities may occur.
- “Construction Activity” includes construction activity as defined in 40 C.F.R. pt. 122.26(b)(14)(x) and small construction activity as defined in 40 C.F.R. pt. 122.26(b)(15) ) and construction activity as defined by Minn. R. 7090.0080, subp. 4. This includes a disturbance to the land that results in a change in the topography, existing soil cover (both vegetative and non-vegetative), or the existing soil topography that may result in accelerated stormwater runoff, leading to soil erosion and movement of sediment into surface waters or drainage systems. Examples of construction activity may include clearing, grading, filling, and excavating. Construction activity includes the disturbance of less than one acre of total land area that is a part of a larger common plan of development or sale if the larger common plan will ultimately disturb one (1) acre or more. Construction activity does not include a disturbance to the land of less than five (5) acres for the purpose of routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, and or original purpose of the facility.
- “Dewatering” means the removal of surface or ground water to dry and/or solidify a construction site to enable construction activity. Dewatering may require a Minnesota Department of Natural Recourses water appropriation permit and, if dewatering water is contaminated, discharge of such water may require an individual MPCA NPDES/SDS permit.
- “Energy Dissipation” means methods employed at pipe outlets to prevent erosion caused by the rapid discharge of water scouring soils. Examples include, but are not limited to: concrete aprons, riprap, splash pads, and gabions that are designed to prevent erosion.
- “Erosion Prevention” means measures employed to prevent erosion. Examples include but not limited to: soil stabilization practices, limited grading, mulch, temporary erosion protection or permanent cover, and construction phasing.
- “Final Stabilization” means required actions in Part IV.G taken after the completion of construction activities and prior to submitting the NOT that are intended to prevent discharge of pollutants associated with stormwater discharges from the project.
- “Homeowner Fact Sheet” means a fact sheet developed by the MPCA and available on the MPCA Construction Stormwater website to be given to homeowners at the time of sale by a builder to inform the homeowner of the need for, and benefits of, Final Stabilization.
- “Infeasible” means not technologically possible or not economically practicable and achievable in light of the best industry practices.
- “Initiated immediately” means taking an action to commence stabilization as soon as practicable, but no later than the end of the work day, following the day when the earth-disturbing activities have temporarily or permanently ceased, if the Permittee(s) know that construction work on that portion of the site will be temporarily ceased for 14 or more additional calendar days. The following activities can be taken to initiate stabilization:
- prepping the soil for vegetative or non-vegetative stabilization
- applying mulch or other non-vegetative product to the exposed soil area
- seeding or planting the exposed area
- starting any of the activities in # 1 – 3 on a portion of the area to be stabilized, but not on the entire area and
- finalizing arrangements to have stabilization product fully installed in compliance with the applicable deadline for completing stabilization
- “Impervious Surface” means a constructed hard surface that either prevents or retards the entry of water into the soil and causes water to run off the surface in greater quantities and at an increased rate of flow than prior to development. Examples include rooftops, sidewalks, patios, driveways, parking lots, storage areas, and concrete, asphalt, or gravel roads.
- “National Pollutant Discharge Elimination System (NPDES)” means the program for issuing, modifying, revoking, reissuing, terminating, monitoring, and enforcing permits under the Clean Water Act (Sections 301, 318, 402, and 405) and United States Code of Federal Regulations Title 33, Sections 1317, 1328, 1342, and 1345.
- “Natural Buffer” means an area of undisturbed cover surrounding surface waters within which construction activities are restricted. Natural buffer includes the vegetation, exposed rock, or barren ground that exists prior to commencement of earth-disturbing activities.
- “Normal Wetted Perimeter” means the area of a conveyance, such as a ditch, channel, or pipe that is in contact with water during flow events that are expected to occur from a two-year 24-hour storm event.
- “Notice of Termination (NOT)” means notice to terminate coverage under this permit after construction is complete, the site has undergone Final Stabilization, and maintenance agreements for all permanent facilities have been established, in accordance with all applicable conditions of this permit.
- “Operator” means the person designated by the owner, who has day to day operational control and/or the ability to modify project plans and specifications related to the SWPPP. The operator “Homeowner Fact Sheet” means a fact sheet developed by the MPCA and available on the MPCA Construction Stormwater website to be given to homeowners at the time of sale by a builder to inform the homeowner of the need for, and benefits of, Final Stabilization.
- “Owner” means the person or party possessing the title of the land on which the construction activities will occur; or if the construction activity is for a lease, easement, or mineral rights license holder, the party or individual identified as the lease, easement or mineral rights license holder; or the contracting government agency responsible for the construction activity.
- “Permanent Cover” means surface types that will prevent soil failure under erosive conditions. Examples include: gravel, asphalt, concrete, rip rap, roof tops, perennial cover, or other landscaped material that will permanently arrest soil erosion. A uniform perennial vegetative cover ( i.e.must be evenly distributed, without large bare areas,) with a density of 70 percent of the native background vegetative cover for the area must be established on all unpaved areas and areas not covered by permanent structures, or equivalent permanent stabilization measures. Permanent cover does not include the practices listed under temporary erosion protection.
- “Permittee(s)” means the person or persons, firm, or governmental agency or other entity that signs the application submitted to the MPCA and is responsible for compliance with the terms and conditions of this permit.
- “Project(s)” means all construction activity that is planned and/or conducted under a particular permit. The project will occur on the site or sites described in the permit application, the SWPPP and in the associated plans, specifications and contract documents.
- “Public Waters” means all water basins and watercourses that are described in Minn. Stat. § 103G.005 subd. 15.
- “Saturated Soil” means the highest seasonal elevation in the soil that is in a reduced chemical state because of soil voids being filled with water Saturated soil is evidenced by the presence of redoximorphic features or other information.
- “Sediment Control” means methods employed to prevent sediment from leaving the site. Sediment control practices include silt fences, sediment traps, earth dikes, drainage swales, check dams, subsurface drains, bio rolls, rock logs, compost logs, storm drain inlet protection, and temporary or permanent sedimentation basins. A floating silt curtain placed in the water is not a sediment control BMP to satisfy perimeter control requirements in Part IV.C., except as provided for in Part IV.C.2.
- “Stabilize, Stabilized, Stabilization” means the exposed ground surface has been covered by appropriate materials such as mulch, staked sod, riprap, erosion control blanket, mats or other material that prevents erosion from occurring. Grass, agricultural crop or other seeding alone is not stabilization. Mulch materials must achieve approximately 90 percent ground coverage (typically 2 ton/acre).
- “Standard Plates” means generic drawings showing a common or repeated construction activity or practice.
- “Stormwater” is defined under Minn. R. 7077.0105, subp. 41(b), and includes precipitation runoff, stormwater runoff, snowmelt runoff, and any other surface runoff and drainage.
- “Steep Slopes” means slopes that are 3:1 (33.3 percent) or steeper in grade.
- “Storm Water Pollution Prevention Plan (SWPPP)” means a plan for stormwater discharge that includes all required content under Part III of this Permit and which describes the erosion prevention BMPs, sediment control BMPs and Permanent Stormwater Management Systems that, when implemented, will decrease soil erosion on a parcel of land and decrease off-site nonpoint pollution.
- “Surface Water or Waters” means all streams, lakes, ponds, marshes, wetlands, reservoirs, springs, rivers, drainage systems, waterways, watercourses, and irrigation systems whether natural or artificial, public or private, except that surface waters do not include treatment basins or ponds that were constructed from upland. Treatment basins or ponds that were constructed in wetlands and mitigated in accordance with Appendix A.D are also not considered surface waters for purposes of this permit.
- “Temporary Erosion Protection” means methods employed to prevent erosion during construction activities. Examples of temporary erosion protection include, but are not limited to: straw, wood fiber blanket, wood chips, vegetation, and rolled erosion control productsnetting.
- “Underground Waters” means water contained below the surface of the earth in the saturated zone including, without limitation, all waters whether under confined, unconfined, or perched conditions, in near surface unconsolidated sediment or regolith, or in rock formations deeper underground. The term ground ater shall be synonymous with underground water.
- “Waters of the State” (as defined in Minn. Stat. § 115.01, subd. 22) means all streams, lakes, ponds, marshes, watercourses, waterways, wells, springs, reservoirs, aquifers, irrigation systems, drainage systems and all other bodies or accumulations of water, surface or underground, natural or artificial, public or private, which are contained within, flow through, or border upon the state or any portion thereof.
- “Water Quality Volume” means one (1) inch of runoff from the new impervious surfaces created by this project (calculated as an instantaneous volume) and is the volume of water to be treated in the Permanent Stormwater Management System, as required by this permit.
- “Wetland” or “Wetlands” is defined in Minn. R. 7050.0186, subp. 1a.B. and includes those areas that are inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. Constructed wetlands designed for wastewater treatment are not waters of the state. Wetlands must have the following attributes:
a. A predominance of hydric soils
b. Inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support a prevalence of hydrophytic vegetation typically adapted for life in a saturated soil condition and
c. Under normal circumstances support a prevalence of such vegetation.