This chapter regulates all areas that would be covered by the
regional flood or base flood as shown on the Flood Insurance Rate
Map (FIRM) or other maps approved by DNR. Base flood elevations are
derived from the flood profiles in the Flood Insurance Study (FIS)
and are shown as AE and AH Zones on the FIRM. Other regulatory zones
are displayed as A and AO Zones on the FIRM. Regional flood elevations
(RFE) may be derived from other studies and are not shown on the FIRM.
If more than one map or revision is referenced, the most restrictive
information shall apply.
Discrepancies between boundaries on the Official Floodplain Zoning Map and actual field conditions shall be resolved using the criteria in Subsections A and B below. If a significant difference exists, the map shall be amended according to Article
VIII, Amendments. The Zoning Administrator can rely on a boundary derived from a profile elevation to grant or deny a land use permit, whether or not a map amendment is required. The Zoning Administrator shall be responsible for documenting actual predevelopment field conditions and the basis upon which the district boundary was determined and for initiating any map amendments required under this section. Disputes between the Zoning Administrator and an applicant over the district boundary line shall be settled according to §
580-35D and the criteria in Subsections
A and
B below. Where the flood profiles are based on established base flood elevations from a FIRM, FEMA must approve any map amendment or revision pursuant to Article
VIII, Amendments.
A. If flood profiles exist, the map scale and the profile elevations
shall determine the district boundary. The regional or base flood
elevations shall govern if there are any discrepancies.
B. Where flood profiles do not exist for projects, the location of the
boundary shall be determined by the map scale.
Compliance with the provisions of this chapter shall not be grounds for removing land from the floodplain unless it is filled at least two feet above the regional or base flood elevation, the fill is contiguous to land outside the floodplain, and the map is amended pursuant to Article
VIII, Amendments.
In their interpretation and application, the provisions of this
chapter are the minimum requirements liberally construed in favor
of the governing body and are not a limitation on or repeal of any
other powers granted by the Wisconsin Statutes. If a provision of
this chapter, required by Ch. NR 116, Wis. Adm. Code, is unclear,
the provision shall be interpreted in light of the standards in effect
on the date of the adoption of this chapter or in effect on the date
of the most recent text amendment to this chapter.
The flood protection standards in this chapter are based on
engineering experience and research. Larger floods may occur, or the
flood height may be increased by man-made or natural causes. This
chapter does not imply or guarantee that nonfloodplain areas or permitted
floodplain uses will be free from flooding and flood damages. This
chapter does not create liability on the part of, or a cause of action
against, the municipality or any officer or employee thereof for any
flood damage that may result from reliance on this chapter.
Should any portion of this chapter be declared unconstitutional
or invalid by a court of competent jurisdiction, the remainder of
this chapter shall not be affected.
The Dane and Green County floodplain zoning provisions in effect
on the date of annexation shall remain in effect and shall be enforced
by the municipality for all annexed areas until the municipality adopts
and enforces an ordinance which meets the requirements of Ch. NR 116,
Wis. Adm. Code, and 44 CFR Parts 59 through 72, National Flood Insurance
Program (NFIP). These annexed lands are described on the municipality's
Official Zoning Map. County floodplain zoning provisions are incorporated
by reference for the purpose of administering this section and are
on file in the office of the municipal Zoning Administrator. All plats
or maps of annexation shall show the regional flood elevation and
the floodway location.
The community shall review all permit applications to determine
whether proposed building sites will be reasonably safe from flooding.
If a proposed building site is in a flood-prone area, all new construction
and substantial improvements shall be designed and anchored to prevent
flotation, collapse, or lateral movement of the structure resulting
from hydrodynamic and hydrostatic loads; be constructed with flood-resistant
materials; be constructed to minimize flood damages and to ensure
that utility and mechanical equipment is designed and/or located so
as to prevent water from entering or accumulating within the equipment
during conditions of flooding. Subdivisions shall be reviewed for
compliance with the above standards. All subdivision proposals (including
manufactured home parks) shall include regional flood elevation and
floodway data for any development that meets the subdivision definition
of this chapter and all other requirements in §
580-33A. Adequate drainage shall be provided to reduce exposure to flood hazards, and all public utilities and facilities, such as sewer, gas, electrical, and water systems are to be located and constructed to minimize or eliminate flood damages.
A. Hydraulic and hydrologic analyses.
(1) No floodplain development shall:
(a)
Obstruct flow, defined as development which blocks the conveyance
of floodwaters by itself or with other development, causing any increase
in the regional flood height; or
(b)
Cause any increase in the regional flood height due to floodplain
storage area lost.
(2) The Zoning Administrator shall deny permits if it is determined the proposed development will obstruct flow or cause any increase in the regional flood height, based on the officially adopted FIRM or other adopted map, unless the provisions of Article
VIII, Amendments, are met.
B. Watercourse Alterations. No land use permit to alter or relocate a watercourse in a mapped floodplain shall be issued until the local official has notified in writing all adjacent municipalities, the Department and FEMA regional offices, and required the applicant to secure all necessary state and federal permits. The standards of §
580-15A must be met and the flood-carrying capacity of any altered or relocated watercourse shall be maintained. As soon as is practicable, but not later than six months after the date of the watercourse alteration or relocation and pursuant to Article
VIII, Amendments, the community shall apply for a Letter of Map Revision (LOMR) from FEMA. Any such alterations must be reviewed and approved by FEMA and the DNR through the LOMC process.
C. Chapter 30, 31, Wis. Stats., development. Development which requires a permit from the Department, under Chs. 30 and 31, Wis. Stats., such as docks, piers, wharves, bridges, culverts, dams and navigational aids, may be allowed if the necessary permits are obtained and amendments to the floodplain zoning ordinance are made according to Article
VIII, Amendments.