c. Infiltration rate exemptions. Infiltration practices located in the following areas may be credited toward meeting the requirements under the following conditions, but the decision to infiltrate under any of the following conditions is optional:
i. Where the infiltration rate of the soil measured at the proposed bottom of the infiltration system is less than 0.6 inches per hour using a scientifically credible field test method.
ii. Where the least permeable soil horizon to 5 feet below the proposed bottom of the infiltration system using the U.S. Department of Agriculture method of soils analysis is one of the following: sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay, or clay.
5. Alternate Use. Where alternate uses of runoff are employed, such as for toilet flushing, laundry, or irrigation or storage on green roofs where an equivalent portion of the runoff is captured permanently by rooftop vegetation, such alternate use shall be given equal credit toward the infiltration volume required by this section.
6. Groundwater Standards.
a. Infiltration systems designed in accordance with this section shall, to the extent technically and economically feasible, minimize the level of pollutants infiltrating to groundwater and shall maintain compliance with the preventive action limit at a point of standards application in accordance with ch. NR 140, Wis. Adm. Code. However, if site specific information indicates that compliance with a preventive action limit is not achievable, the infiltration BMP may not be installed or shall be modified to prevent infiltration to the maximum extent practicable. b. Notwithstanding subd. 6. a., the discharge from BMPs shall remain below the enforcement standard at the point of standards application.
7. Pretreatment. Before infiltrating runoff, pretreatment shall be required for parking lot runoff and for runoff from new road construction in commercial, industrial, and institutional areas that will enter an infiltration system. The pretreatment shall be designed to protect the infiltration system from clogging prior to scheduled maintenance and to protect groundwater quality in accordance with subd. 6. Pretreatment options may include, but are not limited to, oil and grease separation, sedimentation, biofiltration, filtration, swales, or filter strips.
8. Maximum Extent Practicable. Where the conditions of subds. 3. and 4. limit or restrict the use of infiltration practices, the performance standard of S. 07 (4) (c) shall be met to the maximum extent practicable.
(d) PROTECTIVE AREAS.
9. Definition. In this paragraph, “protective area” means an area of land that commences at the top of the channel of lakes, streams, and rivers, or at the delineated boundary of wetlands, and that is the greatest of any of the following widths, as measured horizontally from the top of the channel or delineated wetland boundary to the closest impervious surface. However, in this section, “protective area” does not include any area of land adjacent to any stream enclosed within a pipe or culvert, so that runoff cannot enter the enclosure at this location.
a. For outstanding resource waters and exceptional resource waters, 75 feet.
b. For perennial and intermittent streams identified on a U.S. Geological Survey 7.5-minute series topographic map, or a county soil survey map, whichever is more current, 50 feet.
c. For lakes, 50 feet.
d. For wetlands not subject to subd. 1. e. or f., 50 feet.
e. For highly susceptible wetlands, 75 feet. Highly susceptible wetlands include the following types: calcareous fens, sedge meadows, open and coniferous bogs, low prairies, coniferous swamps, lowland hardwood swamps, and ephemeral ponds.
f. For less susceptible wetlands, 10 percent of the average wetland width, but no less than 10 feet nor more than 30 feet. Less susceptible wetlands include: degraded wetland dominated by invasive species such as reed canary grass; cultivated hydric soils; and any gravel pits, or dredged material or fill material disposal sites that take on the attributes of a wetland.
g. In subd. 1 d. to f., determinations of the extent of the protective area adjacent to wetlands shall be made on the basis of the sensitivity and runoff susceptibility of the wetland in accordance with the standards and criteria in s. NR 103.03, Wis. Adm. Code. h. Wetland boundary delineation shall be made in accordance with s. NR 103.08 (1m), Wis. Adm. Code. This subd. 1. h. does not apply to wetlands that have been completely filled in compliance with all applicable state and federal regulations. The protective area for wetlands that have been partially filled in compliance with all applicable state and federal regulations shall be measured from the wetland boundary delineation after a fill has been placed. Where there is a legally authorized wetland fill, the protective area standard need not be met in that location. i. For concentrated flow channels with drainage areas greater than 130 acres, 10 feet.
j. Notwithstanding subd. 1. a. to i., the greatest protective area width shall apply where rivers, streams, lakes, and wetlands are contiguous.
Note to Users: A stream or lake is not eligible for a lower protective area width even if contiguous to a less susceptible wetland.
10. Applicability. This section applies to post-construction sites located within a protective area, except those areas exempted pursuant to subd. 4.
11. Requirements. All of the following requirements shall be met:
a. Impervious surfaces shall be kept out of the protective area entirely or to the maximum extent practicable. If there is no practical alternative to locating an impervious surface in the protective area, the storm water management plan shall contain a written, site-specific explanation.
b. Where land disturbing construction activity occurs within a protective area, adequate sod or self-sustaining vegetative cover of 70 percent or greater shall be established and maintained where no impervious surface is present. The adequate sod or self-sustaining vegetative cover shall be sufficient to provide for bank stability, maintenance of fish habitat, and filtering of pollutants from upslope overland flow areas under sheet flow conditions. Non-vegetative materials, such as rock riprap, may be employed on the bank as necessary to prevent erosion such as on steep slopes or where high velocity flows occur.
Note to Users: It is recommended that seeding of non-invasive vegetative cover be used in the protective areas. Some invasive plants that should not be used are listed in ch. NR 40, Wis. Adm. Code. Flood and drought-tolerant vegetation that can provide long-term bank stability because of an extensive root system is preferable. Vegetative cover may be measured using the line transect method described in the University of Wisconsin extension publication number A3533, titled “Estimating Residue Using the Line Transect Method.” c. BMPs such as filter strips, swales, or wet detention ponds, that are designed to control pollutants from non-point sources, may be located in the protective area.
Note to Users: Other laws, such as ch. 30, Wis. Stats., and ch. NR 103, 115, 116, and 117, Wis. Adm. Code, and their associated review and approval processes may apply in the protective area. 12. Exemptions. This section does not apply to any of the following:
a. Except as provided under S. 07 (3), redevelopment post-construction sites.
b. In-fill development areas less than 5 acres.
c. Structures that cross or access surface water such as boat landings, bridges, and culverts.
d. Structures constructed in accordance with s. 59.692 (1v), Wis. Stats. e. Areas of post-construction sites from which the runoff does not enter the surface water, including wetlands, without first being treated by a BMP to meet the local ordinance requirements for total suspended solids and peak flow reduction, except to the extent that vegetative ground cover is necessary to maintain bank stability.
Note to Users: A vegetated protective area to filter runoff pollutants from post-construction sites described in par. (e) is not necessary since the runoff at that location is treated prior to entering the surface water. Other practices necessary to meet the requirements of this section, such as a swale or pond, will need to be designed and implemented to reduce runoff pollutants prior to runoff entering a surface water of the state.
(e) FUELING AND MAINTENANCE AREAS. Fueling and vehicle maintenance areas shall have BMPs designed, installed, and maintained to reduce petroleum within runoff, so that the runoff that enters waters of the state contains no visible petroleum sheen, or to the maximum extent practicable.
Note to Users: A combination of the following BMPs may be used: oil and grease separators, canopies, petroleum spill cleanup materials, or any other structural or non-structural method of preventing or treating petroleum in runoff.
Note to Users: The following paragraph, “Swale Treatment for Transportation Facilities,” is optional.
(f) SWALE TREATMENT FOR TRANSPORTATION FACILITIES.
1. Requirement. Except as provided in subd. 2., transportation facilities that use swales for runoff conveyance and pollutant removal are exempt from the requirements of local ordinance requirements for peak flow control, total suspended solids control, and infiltration, if the swales are designed to do all of the following or to the maximum extent practicable:
a. Swales shall be vegetated. However, where appropriate, non-vegetative measures may be employed to prevent erosion or provide for runoff treatment, such as rock riprap stabilization or check dams.
Note to Users: It is preferred that tall and dense vegetation be maintained within the swale due to its greater effectiveness at enhancing runoff pollutant removal.
b. Swales shall comply with sections V.F. (Velocity and Depth) and V.G. (Sale Geometry Criteria) with a swale treatment length as long as that specified in section V.C. (Pre-Treatment) of the Wisconsin Department of Natural Resources technical standard 1005 “Vegetated Swale,” dated September 2016, or a superseding document. Transportation facility swale treatment does not have to comply with other sections of technical standard 1005.
2. Other requirements.
i. Notwithstanding subd. 1., the [administering authority] may, consistent with water quality standards, require that other requirements, in addition to swale treatment, be met on a transportation facility with an average daily traffic rate greater than 2,500 and where the initial surface water of the state that the runoff directly enters is any of the following:
ii. An outstanding resource water.
ii. An exceptional resource water.
iii. Waters listed in section 303 (d) of the Federal Clean Water Act that are identified as impaired in whole or in part, due to non-point source impacts.
iv. Water where targeted performance standards are developed pursuant to s. NR 151.004, Wis. Adm. Code. b. The transportation facility authority shall contact the [administering authority] to determine if additional BMPs beyond a water quality swale are needed under this paragraph.
(5) GENERAL CONSIDERATIONS FOR STORM WATER MANAGEMENT MEASURES. All of the following considerations shall be observed in on-site and off-site runoff management:
(a) Natural topography and land cover features such as natural swales, natural depressions, native soil infiltrating capacity, and natural groundwater recharge areas shall be preserved and used, to the extent possible, to meet the requirements of this section.
(b) Emergency overland flow for all storm water facilities shall be provided to prevent exceeding the safe capacity of downstream drainage facilities and prevent endangerment of downstream property or public safety.
(6) BMP LOCATION.
(a) To comply with the performance standards required under S. 07 of this ordinance, BMPs may be located on-site or off-site as part of a regional storm water device, practice or system, but shall be installed in accordance with s. NR 151.003, Wis. Adm. Code. Note to Users: This section does not supersede any other applicable federal, state or local regulation such as ch. NR 103, Wis. Adm. Code, and ch. 30, Wis. Stats. (b) The [administering authority] may approve off-site management measures provided that all of the following conditions are met:
1. The [administrating authority] determines that the post-construction runoff is covered by a storm water management system plan that is approved by the [name of municipality] and that contains management requirements consistent with the purpose and intent of this ordinance.
2. The off-site facility meets all of the following conditions:
a. The facility is in place.
b. The facility is designed and adequately sized to provide a level of storm water control equal to or greater than that which would be afforded by on-site practices meeting the performance standards of this ordinance.
c. The facility has a legally obligated entity responsible for its long-term operation and maintenance.
(c) Where a regional treatment option exists such that the [administering authority] exempts the applicant from all or part of the minimum on-site storm water management requirements, the applicant shall be required to pay a fee in an amount determined in negotiation with the [administering authority]. In determining the fee for post-construction runoff, the [administering authority] shall consider an equitable distribution of the cost for land, engineering design, construction, and maintenance of the regional treatment option.
(7) ADDITIONAL REQUIREMENTS. The [administering authority] may establish storm water management requirements more stringent than those set forth in this ordinance if the [administering authority] determines that the requirements are needed to control storm water quantity or control flooding, comply with federally approved total maximum daily load requirements, or control pollutants associated with existing development or redevelopment.
S. 08 PERMITTING REQUIREMENTS, PROCEDURES, AND FEES.
(1) PERMIT REQUIRED. No responsible party may undertake a land disturbing construction activity without receiving a post-construction runoff permit from the [administering authority] prior to commencing the proposed activity.
(2) PERMIT APPLICATION AND FEES. Unless specifically excluded by this ordinance, any responsible party desiring a permit shall submit to the [administering authority] a permit application on a form provided by the [administering authority] for that purpose, subject to all of the following:
(a) Unless otherwise excluded by this ordinance, a permit application must be accompanied by a storm water management plan, a maintenance agreement, and a non-refundable permit administration fee.
(b) The storm water management plan shall be prepared to meet the requirements of S. 07 and S. 09, the maintenance agreement shall be prepared to meet the requirements of S. 10, the financial guarantee shall meet the requirements of S. 11, and fees shall be those established by the [governing body] as set forth in S. 12.
(3) PERMIT APPLICATION REVIEW AND APPROVAL. The [administering authority] shall review any permit application that is submitted with a storm water management plan, maintenance agreement, and the required fee. The following approval procedure shall be used:
(a) Within [number] business days of the receipt of a complete permit application, including all items as required by sub. (2), the [administering authority] shall inform the applicant whether the application, storm water management plan, and maintenance agreement are approved or disapproved based on the requirements of this ordinance.
(b) If the storm water permit application, storm water management plan, and maintenance agreement are approved, or if an agreed upon payment of fees in lieu of storm water management practices is made, the [administering authority] shall issue the permit.
(c) If the storm water permit application, storm water management plan, or maintenance agreement is disapproved, the [administering authority] shall detail in writing the reasons for disapproval.
(d) The [administering authority] may request additional information from the applicant. If additional information is submitted, the [administering authority] shall have [number] business days from the date the additional information is received to inform the applicant that the storm water management plan and maintenance agreement are either approved or disapproved.
(e) Failure by the [administering authority] to inform the permit applicant of a decision within [number] business days of a required submittal shall be deemed to mean approval of the submittal and the applicant may proceed as if a permit had been issued.
(4) PERMIT REQUIREMENTS. All permits issued under this ordinance shall be subject to all of the following conditions, and holders of permits issued under this ordinance shall be deemed to have accepted these conditions. The [administering authority] may suspend or revoke a permit for violation of a permit condition, following written notification of the responsible party. An action by the [administering authority] to suspend or revoke a permit may be appealed in accordance with S. 14.
(a) Compliance with a permit does not relieve the responsible party of the responsibility to comply with other applicable federal, state, and local laws and regulations.
(b) The responsible party shall design and install all structural and non-structural storm water management measures in accordance with the approved storm water management plan and permit.
(c) The responsible party shall notify the [administering authority] at least [number] business days before commencing any work in conjunction with the storm water management plan, and within [number] business days upon completion of the storm water management practices. If required as a special condition under sub. (5), the responsible party shall make additional notification according to a schedule set forth by the [administering authority] so that practice installations can be inspected during construction.
(d) Practice installations required as part of this ordinance shall be certified ”as built” or “record” drawings by a licensed professional engineer. Completed storm water management practices must pass a final inspection by the [administering authority] or its designee to determine if they are in accordance with the approved storm water management plan and ordinance. The [administering authority] or its designee shall notify the responsible party in writing of any changes required in such practices to bring them into compliance with the conditions of a permit.
(e) The responsible party shall notify the [administering authority] of any significant modifications it intends to make to an approved storm water management plan. The [administering authority] may require that the proposed modifications be submitted to it for approval prior to incorporation into the storm water management plan and execution by the responsible party.
(f) The responsible party shall maintain all storm water management practices in accordance with the storm water management plan until the practices either become the responsibility of the [governing body], or are transferred to subsequent private owners as specified in the approved maintenance agreement.
(g) The responsible party authorizes the [administering authority] to perform any work or operations necessary to bring storm water management measures into conformance with the approved storm water management plan, and consents to a special assessment or charge against the property as authorized under subch. VII of ch. 66, Wis. Stats., or to charging such costs against the financial guarantee posted under S. 11. (h) If so directed by the [administering authority], the responsible party shall repair at the responsible party’s own expense all damage to adjoining municipal facilities and drainage ways caused by runoff if such damage is caused by activities that are not in compliance with the approved storm water management plan.
(i) The responsible party shall permit property access to the [administering authority] or its designee for the purpose of inspecting the property for compliance with the approved storm water management plan and permit.
(j) Where site development or redevelopment involves changes in direction, increases in peak rate and/or total volume of runoff from a site, the [administering authority] may require the responsible party to make appropriate legal arrangements with affected property owners concerning the prevention of endangerment to property or public safety.
(k) The responsible party is subject to the enforcement actions and penalties detailed in S. 13, if the responsible party fails to comply with the terms of the permit.
(5) PERMIT CONDITIONS. Permits issued under this subsection may include conditions established by [administering authority] in addition to the requirements needed to meet the performance standards in S. 07 or a financial guarantee as provided for in S. 11.
