Chapter NR 116

NR 116.14(2)(b) (b) Flood storage modifications. When any proposed development would remove flood storage volume, an equal volume of storage, as defined by the ground surface and the regional flood elevation, shall be provided to compensate for the volume of storage which is lost. Excavation below the groundwater table is not considered as providing an equal volume of storage.

NR 116.14(2)(c) (c) Rezoning of flood storage district. If compensatory storage cannot be provided, the area may not be developed unless the entire flood storage district is rezoned to floodfringe district utilizing the criteria established in s. NR 116.11 (2) (e).

NR 116.14(3) (3) Coastal floodplain district. The standards for permitting development in a floodfringe area under s. NR 116.13 shall be applicable in a coastal floodplain area, except that no development may be allowed which:

NR 116.14(3)(a) (a) Will be adversely affected by wave runup along the shore of Lake Michigan or Lake Superior; or

NR 116.14(3)(b) (b) Is associated with a high flood damage potential.

NR 116.14 History History: Cr. Register, February, 1986, No. 362, eff. 3-1-86.

NR 116.15 NR 116.15 Nonconforming uses and nonconforming buildings.

NR 116.15(1) (1) General. Insofar as the standards in this section are not inconsistent with the provisions of ss. 59.69 (10) and 62.23 (7) (h), Stats., they shall apply to all uses and buildings that do not conform to the provisions contained within a floodplain zoning ordinance. These standards apply to the modification of, or addition to, any building and to the use of any building or premises which was lawful before the passage of the ordinance. The existing lawful use of a building or its accessory use which is not in conformity with the provisions of a floodplain zoning ordinance may be continued subject to the following conditions:

NR 116.15(1)(a) (a) No extension of a nonconforming use, or modification or addition to any building with a nonconforming use or to any nonconforming building, may be permitted unless they are made in conformity with the provisions of this section. For the purposes of this section, the words “modification” and “addition” shall include, but not be limited to, any alteration, addition, modification, rebuilding or replacement of any existing building, accessory building or accessory use, except as provided in pars. (am) and (as).

NR 116.15(1)(am) (am) For the purposes of this section, ordinary maintenance repairs are not considered an extension, modification or addition; ordinary maintenance repairs include internal and external painting, decorating, paneling, the replacement of doors, windows and other nonstructural components; and the maintenance, repair or replacement of existing private sewage systems, water supply systems or connections to public utilities;

NR 116.15(1)(as) (as) For the purposes of this section, the construction of a deck that does not exceed 200 square feet and that is adjacent to the exterior wall of a principal structure is not an extension, modification or addition. The roof of the principal structure may extend over a portion of the deck in order to provide safe ingress and egress to the principal structure.

NR 116.15(1)(b) (b) If a nonconforming use or the use of a nonconforming building is discontinued for 12 consecutive months, it is no longer permitted and any future use of the building shall conform with the appropriate provisions contained in ss. NR 116.12, 116.13 and 116.14.

NR 116.15(1)(c) (c) No modification or addition to any nonconforming building or any building with a nonconforming use, which over the life of the building would exceed 50% of its present equalized assessed value, may be allowed unless the entire building is permanently changed to a conforming building with a conforming use in compliance with the applicable requirements of this chapter. The costs of elevating a nonconforming building or a building with a nonconforming use to the flood protection elevation are excluded from the 50% provisions of this paragraph.

NR 116.15(1)(d) (d) If any nonconforming building or any building with a nonconforming use is destroyed or is so badly damaged that it cannot be practically restored, it cannot be replaced, reconstructed or rebuilt unless the provisions of ss. NR 116.12, 116.13 and 116.14 are met. For the purpose of this subsection, restoration is deemed impracticable where the total cost of such restoration would exceed 50% of the present equalized assessed value of the building.

NR 116.15(2) (2) Floodway areas.

NR 116.15(2)(a) (a) No modifications or addition to any nonconforming building or any building with a nonconforming use in a floodway area may be allowed, unless such modification or addition has been granted by permit, special exception, conditional use or variance and meets all of the requirements of sub. (1) and the following criteria:

NR 116.15(2)(a)1. 1. The modification or addition to a building may not increase the amount of obstruction to flood flows; and

NR 116.15(2)(a)2. 2. Any addition to a building shall be floodproofed in accordance with the requirements of s. NR 116.16, by means other than the use of fill, to the flood protection elevation.

NR 116.15(2)(b) (b) No new private sewage system, or addition to an existing private sewage system, may be allowed in a floodway area. Any maintenance, repair or replacement of a private sewage system in a floodway area shall meet the applicable requirements of all municipal ordinances and ch. SPS 383.

NR 116.15(2)(c) (c) No new well, or modifications to an existing well, which is used to obtain water for ultimate human consumption may be allowed in a floodway area. Any maintenance, repair or replacement of an existing well in a floodway area shall meet the applicable requirements of all municipal ordinances and chs. NR 811 and 812.

NR 116.15(3) (3) Floodfringe areas.

NR 116.15(3)(a) (a) Except as provided in par. (b) or (c), no modification or addition to any nonconforming building or any building with a nonconforming use in the floodfringe area may be allowed unless such modification or addition has been granted by permit, special exception, conditional use or variance and the modification or addition is placed on fill or is floodproofed in compliance with the applicable regulations contained s. NR 116.13 (2).

NR 116.15(3)(b) (b) If compliance with the fill or floodproofing provisions of par. (a) would result in unnecessary hardship, and only if the building will not be used for human habitation and will not be associated with a high flood damage potential, the county board of adjustment or the city or village board of appeals, using the procedures established in s. NR 116.21 (4), may grant a variance for modifications or additions which are protected to elevations lower than the flood protection elevation if:

NR 116.15(3)(b)1. 1. Human lives will not be endangered;

NR 116.15(3)(b)2. 2. Water or private sewage systems will not be installed;

NR 116.15(3)(b)3. 3. Flood depths will not exceed 2 feet;

NR 116.15(3)(b)4. 4. Flood velocities will not exceed 2 feet per second; and

NR 116.15(3)(b)5. 5. The building will not be used for storage of materials described in s. NR 116.13 (6).

NR 116.15(3)(c) (c) An addition to an existing room in a nonconforming building or a building with a nonconforming use may be allowed in a floodfringe area on a one time basis only if:

NR 116.15(3)(c)1. 1. The addition has been granted by permit, special exception, conditional use or variance;

NR 116.15(3)(c)2. 2. The addition does not exceed 60 square feet in area; and

NR 116.15(3)(c)3. 3. The addition, in combination with other modifications or additions to the building, does not exceed 50% of the present equalized assessed value of the building.

NR 116.15(3)(d) (d) All new private sewage systems, or additions to, maintenance, repair or replacement of a private sewage system, in a floodfringe area shall meet the applicable requirements of all municipal ordinances and ch. SPS 383.

NR 116.15(3)(e) (e) All new wells, or additions to, replacement, repair or maintenance of a well, in a floodfringe area shall meet the applicable provisions of the floodplain zoning ordinance and chs. NR 811 and 812.

NR 116.15(4) (4) Shallow depth flooding area. No structural repairs, modifications or additions to an existing building, the cost of which exceeds, over the life of the existing building, 50% of its present equalized assessed value, may be allowed in a shallow depth flooding area unless the entire building is permanently changed to conform with the standards prescribed in s. NR 116.14 (1).

NR 116.15(5) (5) Flood storage area. No structural repairs, modifications or additions to an existing building, the cost of which exceeds, over the life of the existing building, 50% of its present equalized assessed value, may be allowed in a flood storage area unless the entire building is permanently changed to conform with the standards prescribed in s. NR 116.14 (2).

NR 116.15(6) (6) Coastal floodplain area. No structural repairs, modifications or additions to an existing building, the cost of which exceeds, over the life of the existing building, 50% of its present equalized assessed value, may be allowed in a coastal floodplain area unless the entire building is permanently changed to conform with the standards prescribed in s. NR 116.14 (3).

NR 116.15(7) (7) Municipal responsibilities.

NR 116.15(7)(a) (a) Municipal floodplain zoning ordinances shall regulate nonconforming uses and nonconforming buildings in a manner consistent with this section and the applicable state statutes. These regulations shall apply to the modification or addition of any building or to the extension of the use of any building or premises which was lawful before the passage of the floodplain zoning ordinance or any amendment thereto.

NR 116.15(7)(b) (b) As permit applications are received for modifications or additions to nonconforming buildings in the floodplain, municipalities shall develop a list of those nonconforming buildings, their present equalized assessed value and a list of the costs of those activities associated with changes to those buildings enumerated in sub. (2) (a) or (3) (a), (b) and (c).

NR 116.15 History History: Cr. Register, February, 1986, No. 362, eff. 3-1-86; correction in (2) (c) and (3) (e) made under s. 13.93 (2m) (b) 7., Stats., Register, September, 1995, No. 477; correction in (1) (intro.) was made under s. 13.93 (2m) (b) 7., Stats., Register July 2001, No. 547; CR 03-064: am. (1) (c) Register April 2004 No. 580, eff. 5-1-04; CR 03-091: am. (1) (a), cr. (1) (am) and (as), Register August 2004 No. 584, eff. 9-1-04; corrections in (2) (b), (3) (d) made under s. 13.92 (4) (b) 7., Stats., Register January 2012 No. 673.

NR 116.16 NR 116.16 Floodproofing.

NR 116.16(1) (1) General standards. When floodproofing measures are required by either a municipal floodplain zoning ordinance or some other regulation which incorporates by reference the floodproofing requirements of this chapter, such measures shall be designed to withstand the flood depths, pressures, velocities, impact and uplift forces and other factors associated with the regional flood, to assure that the structures are watertight and completely dry to the flood protection elevation without human intervention during flooding.

NR 116.16(2) (2) Certification.

NR 116.16(2)(a) (a) Whenever floodproofing measures are required, a registered professional engineer or architect shall certify that the following floodproofing measures will be utilized, where appropriate, and are adequate to withstand the flood depths, pressures, velocities, impact and uplift forces and other factors associated with the regional flood:

NR 116.16(2)(a)1. 1. Anchorage of structures, or addition of mass or weight to structures, to prevent flotation.

NR 116.16(2)(a)2. 2. Reinforcement of walls and floors to resist rupture or collapse caused by water pressures or floating debris.

NR 116.16(2)(a)3. 3. Construction of wells, water supply systems and waste treatment systems so as to prevent the entrance of flood waters into such systems.

NR 116.16(2)(a)4. 4. Subsurface drainage systems to relieve external pressures on foundation walls and basement floors.

NR 116.16(2)(a)5. 5. Cutoff valves on sewer lines or the elimination of gravity flow basement drains.

NR 116.16(2)(a)6. 6. Placement of essential utilities above the flood protection elevation.

NR 116.16(2)(b) (b) Whenever floodproofing measures are required, a permit, special exception, conditional use or variance may not be issued until the certification required in par. (a) is submitted to the municipal zoning administrator.

NR 116.16 History History: Cr. Register, February, 1986, No. 362, eff. 3-1-86.

NR 116.17 NR 116.17 Levees, floodwalls and channel improvements.

NR 116.17(1) (1) General. The following standards shall apply to municipal floodplain zoning regulations for areas landward of levees, floodwalls and channel improvements.

NR 116.17(2) (2) Levees or floodwalls.

NR 116.17(2)(a) (a) A levee or floodwall shall be considered adequate if all of the following criteria and the requirements of par. (b) are met:

NR 116.17(2)(a)1. 1. The minimum top elevation of the levee or floodwall shall be calculated using whichever of the following provides the greater protection from floods:

NR 116.17(2)(a)1.a. a. The profile of the regional flood with that regional flood confined riverward of the proposed levee or floodwall, plus 3 feet of freeboard; or

NR 116.17(2)(a)1.b. b. The standard project flood and/or the 500 year flood confined riverward of the proposed levee or floodwall.

NR 116.17(2)(a)1.c. c. Exceptions to the standards in subd. 1. a. and b. may be granted by the department on a case-by-case basis for levees and floodwalls not used to protect human life.

NR 116.17(2)(a)2. 2. U.S. army corps of engineers standards for design and construction of levees and floodwalls shall be the minimum standard for levees and floodwalls.

NR 116.17(2)(a)3. 3. Interior drainage shall be provided using designated ponding areas, pumps or other similar means, in accordance with U.S. army corps of engineers standards.

NR 116.17(2)(a)4. 4. An emergency action plan, concurred in by the division of emergency government and approved by the department, shall be in effect for the area behind the levee or floodwall that would be in the floodplain without the proposed levee or floodwall in place.

NR 116.17(2)(a)5. 5. The municipality shall provide notification to all persons receiving construction permits in the area behind the proposed levee or floodwall that would be in the floodplain without the proposed levee or floodwall in place that they are in an area protected by a levee or floodwall which is subject to flooding if the levee or floodwall is overtopped.

NR 116.17(2)(a)6. 6. The levee or floodwall shall be annually inspected and certified, by a professional engineer registered in Wisconsin, that the levee or floodwall meets the standards in subds. 1. to 5. Annual reports of the inspection and certification shall be sent to the department for review.

NR 116.17(2)(a)7. 7. The department reviews and approves the material submitted under subds. 1. to 5.

NR 116.17(2)(b) (b) No obstruction to flood flows caused by construction of levees or floodwalls may be allowed unless amendments are made to the floodway lines, regional flood profiles, floodplain zoning maps and floodplain zoning ordinances in accordance with the provisions of ss. NR 116.11, 116.12 (3) and 116.21 (6). Calculations of the effect of the levee or floodwall on regional flood heights shall compare existing conditions with the condition of the regional flood confined riverward of the proposed levee or floodwall.

NR 116.17(2)(c) (c) Floodplain areas protected by the adequate levee or floodwall shall be designated as flood fringe but may be regulated as areas outside of the floodplain unless the department determines that the levee or floodwall is no longer adequate.

NR 116.17(3) (3) Inadequate levees or floodwalls. If the department determines that an existing levee or floodwall does not meet the criteria of sub. (2) (a), all floodplain areas landward of the inadequate levee or floodwall shall be regulated as if the levee or floodwall does not exist.

NR 116.17(4) (4) Channel improvements.

NR 116.17(4)(a) (a) Channel improvements shall be considered to reduce flooding potential provided the following criteria are met:

NR 116.17(4)(a)1. 1. The channel improvements are designed and constructed in accordance with acceptable standards.

NR 116.17(4)(a)2. 2. Velocities resulting from the channel improvements will not increase downstream erosion.

NR 116.17(4)(a)3. 3. An engineer registered in Wisconsin certifies that the criteria in subds. 1. and 2. are met.

NR 116.17(4)(a)4. 4. The municipality submits a plan detailing how the channel improvements will be maintained.

NR 116.17(4)(a)5. 5. The department reviews and approves the material submitted under subds. 1. to 4.

NR 116.17(4)(a)6. 6. The necessary permits under ch. 30, Stats., are obtained for construction of the channel improvements.

NR 116.17(4)(b) (b) Floodplain areas adjacent to channel improvements approved under par. (a) shall be zoned and regulated in accordance with the reduced regional flood profile provided the channel improvements are maintained in accordance with the plan submitted by the municipality under par. (a) 4.

NR 116.17(4)(c) (c) If the department determines that the channel improvements are not being maintained in accordance with the plan submitted by the municipality under par. (a) 4., the floodplain zoning map shall be amended to reflect existing channel conditions.

NR 116.17(5) (5) New construction of levees, floodwalls or channel improvements. No anticipated changes in the flood protection elevations or floodplain and floodway limits, based upon proposed levees, floodwalls or channel improvements, may be effective until the improvements are constructed, operative and approved by the department.

NR 116.17(6) (6) Agricultural levees.

NR 116.17(6)(a) (a) Municipalities may permit agricultural levees which meet all applicable provisions of this subsection. For purposes of this subsection, an agricultural levee is one constructed to protect agricultural lands from floods that occur on a 10-year frequency or more often.

NR 116.17(6)(b) (b) Agricultural levees shall be designed and constructed so that the levees will overtop upon the occurrence of the 10-year frequency flood.

NR 116.17(6)(c) (c) Increases in flood heights in the area upstream from agricultural levees may not exceed 0.5 foot (15 cm.) for the 10-year frequency flood. No increase is allowed unless the written consent of the affected property owners is obtained prior to construction.

NR 116.17(6)(d) (d) Agricultural levees shall be designed and constructed to be overtopped and to cause no increase in flood elevation during the occurrence of the regional flood.

NR 116.17(6)(e) (e) The municipality’s zoning administrator shall notify the department of the construction of any agricultural levees.

NR 116.17 History History: Cr. Register, February, 1986, No. 362, eff. 3-1-86.

NR 116.18 NR 116.18 Procedures for changing floodplain, floodway, floodfringe, shallow depth flooding, flood storage and coastal floodplain district limits. Municipalities may not change the limits of the floodplain or the floodway, floodfringe, shallow depth flooding, flood storage or the coastal floodplain district without first amending the applicable portions of the water surface profiles, floodplain zoning maps and floodplain zoning ordinances in accordance with s. NR 116.11 and securing department approval for such amendments. No area in the floodplain may be removed from the floodplain unless it can be shown that the area has been filled to the flood protection elevation and is contiguous to other lands lying outside the floodplain.