Floodplains_Content Page_Regulations and ordinances

Regulations and ordinances

Regulations

Communities are required under s. 87.30, Wis. Stats. to adopt a reasonable and effective floodplain ordinance within one year after hydraulic and engineering data adequate to formulate the ordinance becomes available. Communities are also required to adopt an ordinance that meets the minimum standards of 44 CFR 59-72 if they wish to participate in the National Flood Insurance Program (NFIP) and have flood insurance available.

The purpose of the floodplain regulations are to:

  • protect life, health and property;
  • minimize public expenditures for costly flood control projects;
  • minimize rescue and relief efforts;
  • minimize business interruptions;
  • minimize damage to public facilities;
  • minimize the occurrence of future flood blight areas;
  • discourage the victimization of unwary land and home buyers; and
  • prevent increases in the regional flood from occurring.

The Wisconsin model floodplain ordinance incorporates both the NFIP and state minimum standards to ensure the health and safety of people living in or near the floodplain. Some of these standards include:

  • prohibition of new construction of residential, commercial or industrial structures in the floodway;
  • In the flood fringe:
    • lowest floor elevated on fill two feet or more above the regional flood elevation (basement floor can be at regional flood elevation);
    • fill must be one foot or more above regional flood elevation;
    • structures must have dryland access; and
    • creation of flood storage districts.
  • Flood Shadows of Dams
    • The flood shadow of any dam, statutorily defined as large, is regulated as floodplain. A dam failure analysis is the engineering study that generates the flood shadow map. The flood shadow, flood profile and floodway data tables generated in the DFA must be adopted in the official maps section of the community floodplain zoning ordinance.

Areas to be regulated

The regulatory requirements of ch. NR 116, Wis. Admin. Code and the NFIP apply in those areas that have been mapped by FEMA as being at risk to flooding during the base flood and those areas which have been mapped by the DNR for flood storage. Local ordinances must include the minimum standards of ch. NR 116 and 44 CFR 59-72 if the community participates in the NFIP or if the community has mapped floodplain within its political boundary. Communities can adopt higher regulatory standards to meet local conditions, if desired.

Areas at risk to flooding are shown on the Flood Insurance Rate Maps (FIRMs) produced by FEMA. The FIRMs are based on the Flood Insurance Study (FIS), which has information that can be used to develop detailed information on the flood risk for a specific property. Flood storage areas are shown on Flood Storage maps which are provided to affected communities by the DNR.

What is regulated?

Floodplain ordinances regulate all development in the floodplain. Development in the floodplain is defined in 44 CFR 59.1 as any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations or storage of equipment or materials. This definition includes culverts, bridges and roads.

Floodplain development is managed through local floodplain ordinances. All local floodplain ordinances must meet the minimum requirements of the National Flood Insurance Program found in 44 CFR 59-72 and ch. NR 116, Wis. Admin Code. To assist communities in writing a compliant floodplain ordinance, the department has developed a model ordinance.

Floodplain ordinances are adopted at the local level in the same manner as any other ordinance. The community must advertise and hold a public hearing under the Class II notice process defined in statute. Similarly, after the adoption, the community must either publish the adopted ordinance in its entirety or publish a summary of the ordinance using a Class I notice process defined in statute. If the community does not have an official newspaper, it may post the required notices in lieu of publication.

Once it is adopted, the ordinance along with the affidavits and notices of public hearing and adoption must be sent to the DNR for review and approval. A copy of the ordinance must also be sent to FEMA for review and approval if the community participates in the NFIP. DNR staff coordinate the FEMA approval and sending the ordinance to FEMA on behalf of the community.

For a summary of the ordinance adoption process, please see our Quick guide.

Communities are no longer allowed to adopt official maps used to regulate floodplain development into an appendix to the floodplain zoning ordinance. These maps must be adopted into the official maps section of the floodplain zoning ordinance.

If a community wishes to join the NFIP, and it has floodplain within its political boundary, it will need to adopt an ordinance that meets state and federal minimum standards along with a resolution of intent to join and complete the federal application. Contact DNR Floodplain for information on joining the NFIP.

A community may join the NFIP if there is no mapped floodplain within its political boundaries. These communities can join without adopting a floodplain zoning ordinance. Joining the NFIP under these circumstances would make purchase of federal flood insurance available to citizens of that community that might experience urban flooding, for example.

Information on which communities are participating in the NFIP can be found in FEMA’s Community Status Book. The Community Status Book is updated daily to reflect changes in community status.

Evaluating for the presence/absence of mapped floodplain for potential development projects, issuing floodplain development permits and enforcement of the floodplain regulations are the responsibility of local officials. For most communities, this is the Zoning Administrator. Every community that participates in the NFIP must have the FIRMs and FIS available for the public to view. Communities that do not adequately enforce the local floodplain ordinance can be penalized by FEMA through probation or suspension from the NFIP. Violations of the minimum requirements of ch. NR 116 can result in enforcement action by the DNR.

Definitions and Acronyms

More floodplain management acronyms and definitions.