Fiscal Note
No appropriation required.
Title
Creating Section 28.06(3)(c) and amending Sec. 28.105(4) of the Madison General Ordinances to make Flood Storage provisions consistent with State code.
Body
DRAFTER'S ANALYSIS: The Department of Natural Resources recently identified flood storage areas on the Floodplain Maps. Because municipalities' floodplain ordinances must be consistent with the Wisconsin Administrative Code, amendments to the city's floodplain ordinances are necessary.
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1. Subdivision (c) entitled "Incorporation of Flood Storage Maps" of Subsection (3) entitled "Floodplain Maps" of Section 28.06 entitled "Zoning Districts and Zoning District Maps" of the Madison General Ordinances is created to read as follows:
"(c) Incorporation of Flood Storage Maps. The location and boundaries of the Flood Storage Districts are hereby established as shown on Panels 2, 3, 4 and 5 of the Dane County Flood Storage Maps, dated January 2, 2009."
2. Subsection (4) entitled "F4 Flood Storage District" of Section 28.105 entitled "Flood Plain Districts" of the Madison General Ordinances is amended to read as follows:
"(4) F4 Flood Storage District.
(a) Applicability. The F4 Flood Storage District consists of that portion of the floodplain where storage of floodwaters is calculated to reducehas been taken into account and is relied upon to reduce the regional flood discharge. The district provides for the protections of the flood storage areas and assures that any development in the storage areas will not decrease the effective flood storage capacity, which would cause higher floodplain elevations. The provisions of this section shall apply to all areas within the F4 Flood Storage District and to those portions of the F3 General Floodplain District determined to be in the flood storage areas shown on the Dane County Flood Storage Maps.
(bc) Standards for Development in Flood Storage District. In addition to the Standards for Development in Sec. 28.105(2)(c), MGO, the following standards shall apply.
1. Development in a flood storage district shall not cause an increase equal to or greater than 0.01 of a foot in the height of the regional flood.
2. No development shall be allowed that would remove flood storage volume, unless an equal volume of storage, as defined by the predevelopment ground surface and the regional flood elevation, shall be provided in the immediate area of the proposed development to compensate for the volume of storage which is lost (compensatory storage). Excavation below the groundwater table is not considered to provide an equal volume of storage.
3. No area in the floodplain may be removed from the flood storage district 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.
4. If compensatory storage cannot be provided, the area may not be developed unless the entire area zoned as flood storage district is rezoned to the floodfringe district. At such time, the floodplain study and map for the waterway shall be revised to revert to the higher regional flood discharge calculated without floodplain storage.
(c) Rezone from Flood Storage District to Flood Fringe District.
1. Department of Natural Resources approval of any project that results in an increase in the height of the regional flood shall be secured prior to the submitting of a petition to rezone.
2. The effect of rezoning from the flood storage district to the flood fringe district shall be calculated by comparing the current flood profile to the flood profile determined by assuming that the area to be rezoned is not available to store floodwater.
3. The zoning maps for the flood storage district may not be amended without first amending the applicable portions of the water surface profiles, and floodplain zoning ordinances and securing Department of Natural Resources approval for such amendments.
db) Permitted Uses. The following uses are permitted in the F4 Flood Storage District:
1. Any use permitted in the F1 Floodway District allowed as permitted or conditional uses in the Madison Zoning Ordinance, except for mobile home parks and solid waste disposal sites.
(ed) Nonconforming Uses. No modifications or additions shall be allowed to any nonconforming structure in a flood storage district unless the standards in Sec. 28.105(4)(b)(c) above are met."