Floodplain and Shoreline Regulations

Lake Monona is a valuable resource to the Monona community, but living along the lake also brings flooding risks. As the City experiences more frequent and severe rain events, it’s important for property owners to understand the policies that regulate areas that are prone to flooding, especially for water-front properties. Many of Monona’s waterfront properties fall within flood-hazard boundaries that are regulated by the Federal Emergency Management Agency (FEMA), the Wisconsin Department of Natural Resources (DNR) and the City’s Floodplain and Shoreline Zoning Codes. It is crucial for property owners to understand regulations and permits that apply to them before beginning home-improvement and flood-proofing projects. This page is designed to guide residents through those regulations and provide resources for flood-proofing projects.

Sign up for City Emergency Alerts, including flooding events, on the Notify Me Page.

Important Terminology

100 Year Flood/Regional Flood
The regional flood for a community is a flood that has a 1% chance of happening each year. It is commonly referred to as a 100 year flood, even though they can happen more than once every 100 years.
Compensatory Storage
Compensatory storage is an area created within the FSD that replaces floodwater storage that has been removed or filled in. Replacing floodwater storage is required for any fill placed within the FSD.
Flood Storage District (FSD)
The Flood Storage District (FSD) is the area of the floodplain designated as storage for flood water. Storing water in the FSD during a regional flood helps reduce flood elevations further downstream. To protect the storage capacity, development in the FSD is strictly regulated.

Ordinary High Water Mark (OHWM)
The Ordinary High Water Mark is the line  on the lake shore that divides public lake bed and private land. It is determined by the DNR. It is generally defined as the point on the shore where water typically leaves a distinctive mark, like erosion, lack of terrestrial plants, or presence of aquatic plants. Lake Monona’s OHWM is 845.82 feet above sea level.

The strictest regulations apply to the Flood Storage District, where any development or construction that reduces the floodwater storage capacity must provide compensatory storage within the same Flood Storage District. Projects that fall below the Ordinary High Water Mark are under the jurisdiction of the DNR, and have separate regulations and permits. Before starting any construction, it’s important to determine if your property is part of the Flood Storage District, which you can do using the maps below.

Floodplain Maps

City of Monona Floodplain Map

FEMA Flood Map Service Center

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Here you can see what parts of Monona are considered part of the Flood Storage District. It’s possible that only part of a property is considered part of the Flood Storage District. In addition to checking these maps, you should contact City staff and check flood insurance requirements with an insurance agent, if you plan on making changes to your property. 

For information about flood insurance and the National Flood Insurance Program, please visit: https://www.fema.gov/national-flood-insurance-program and speak directly with an insurance agent.

Important Documents

Floodplain Regulations Flyer

Floodplain Development Application

This document is designed to help homeowners determine what governing body to contact regarding their home improvement project. It also provides resources for various project types. This is the official permit application for projects that require approval from the City regarding development within the floodplain. 
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  1. General Resources
  2. Native SHoreline Restoration
  3. Rip Rap
  4. Wetlands

City of Monona Emergency Alerts

During the flooding in the summer of 2018, the City sent daily messages to residents regarding lake levels and forecasts, sandbagging efforts, etc. You can sign up to receive these kinds of messages via email or text message here by clicking on Emergency Alerts.

Flood Storage District Zoning Code

To view Monona’s full zoning code for the Flood Storage District, please click here.

Wisconsin State Statute on Navigable Waters

To see the state of Wisconsin’s statutes regulating navigable waters, which include floodplain regulations, please click here.

Floodplain Development Basics

Read over this helpful handout from the Department of Natural Resources for more general information about floodplain regulations.

Living in the Floodplain

This document, from the Department of Natural Resources, outlines information for anyone who currently lives in a floodplain, or is considering buying property in a floodplain. 

Dane County Lake Level Management Guide

This guide, from the Dane County Land & Water Resources Department, explain how lake levels within the Yahara river shed, including lake Monona, are managed.