State of the Beach/State Reports/WI/Beach Erosion
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The Heinz Center's Evaluation of Erosion Hazards (April 2000) states:
The Great Lakes coasts extend for 3,600 mi (Federal Emergency Management Agency, 1989), and are composed of a variety of shore types, ranging from high rock bluffs to low plains and wetlands. Coastal erosion in the Great Lakes is affected by many factors, including cyclically changing lake levels, disruption of longshore transport of beach building material, and storms. Rates of bluff and dune erosion along the shores of the Great Lakes vary from near zero to tens of feet per year because of annual variability in wave climate and lake levels (National Research Council, 1990). The Great Lakes have experienced a series of high lake levels in the past two decades, with the highest peak occurring in 1987 (U.S. Army Corps of Engineers Detroit District, 1997). High lake levels increase bluff recession rates by increasing wave attack on the base of the bluff.
In many areas of the Great Lakes, bluff erosion produces beach-building sediments. However, both tributary and shoreland sources of sediment are depleted by navigational improvements and dredged material disposal practices, which remove these sediments from the littoral system. Ice ridges that form and break up each winter along the shoreline also cause erosion by trapping sand in floating fragments of ice that are carried offshore into deep water. This continuing natural process is one of the principal mechanisms by which sand is lost from the nearshore system (U.S. Geological Survey, 1992). The hardening of the lakeshore with erosion control structures can also reduce sediment supply and adversely affect natural processes.
The report "State Coastal Program Effectiveness in Protecting Natural Beaches, Dunes, Bluffs, and Rock Shores" (T. Bernd-Cohen and M. Gordon), Coastal Management 27:187-217, 1999, states that the amount of critically eroding shoreline in Wisconsin is unknown.
In general, the erodible sections of the Lake Michigan shore occur from the Illinois state line to the Sturgeon Bay Canal, northeastern Brown County and smaller segments of bays and clay banks. On Lake Superior, erosive high clay bluffs stretch from Bark Point in Bayfield County to Wisconsin Point in Douglas County and from the eastern boarder of Iron County to the White River in Ashland County.
The 2011-2015 Needs Assessment and Strategy states:
- "All fifteen of Wisconsin’s coastal counties experience erosion. Wisconsin's Lake Michigan shoreline is generally vulnerable to shore erosion from the Illinois State line to the Sturgeon Bay Canal, a distance of 185 miles. From the Sturgeon Bay Canal around the northern tip of Door County to Green Bay, shore erosion is largely limited to bays and clay banks. Erosion rates are particularly high along sand plains and high bluffs composed of till. Short-term erosion rates of 3 to 15 feet per year have been recorded along sand plains and 2 to 6 feet per year along high bluff lines. Wisconsin’s Lake Superior shoreline is vulnerable to shore erosion except for rocky portions of the Bayfield Peninsula, the low marshland in Chequamegon Bay, and at the mouth of the Bad River. Portions of Wisconsin’s coasts are at risk of episodic erosion. Unsound development in these hazardous areas can lead to catastrophic events. Coastal erosion is a naturally occurring process that can accelerate during strong storms with high winds or heavy wave actions. Such events can cause sudden failure of bluffs. Freezing and thawing of lake ice can also contribute to erosion."
Portions of Wisconsin’s coasts are at risk of episodic erosion. Unsound development in these hazardous areas can lead to catastrophic events. In 2002, the Village of Oliver, in Douglas County, experienced some severe slumping along the St. Louis River. Seven properties were affected. One of the properties experienced a large ground failure, with an 18-foot scarp approximately one foot from the rear entrance of the home. With assistance from Wisconsin Emergency Management, the Village of Oliver acquired and demolished three of the affected properties. In a separate event, a home in the City of Superior experienced land subsidence in 2001, when the entire yard started moving toward the Nemadji River. Erosion from spring floods caused the ground within fifteen feet of the house to slide downhill; the City of Superior bought the structure and demolished it.
The primary factor controlling erosion is fluctuations in lake levels: when lake levels are high development is threatened by erosion. Periods of high lake levels occurred in 1972-76, 1983-87 and 1996-98. During 1986-87, $16 million in documented damage to public facilities alone was attributed to erosion and flooding. Areas on Lake Michigan vulnerable to coastal flooding include southern Kenosha County, northern Ozaukee and southern Sheboygan Counties, the western shore of Green Bay, and low-lying river mouths in urban areas. Vulnerable Lake Superior areas include sections of the City of Superior and coastal estuaries. The current trend is one of decreasing lake levels. As the 2001 and 2006 Assessments have stated, this gives a false sense of security for construction and development near the shore.
The 2001 Assessment also reported that there were no formal programs for monitoring shoreline recession or bluff erosion. It identified the lack of up-to-date information about coastal hazards, limited coastal hazards education efforts, and an inadequate institutional framework as major impediments to directing new development away from hazardous areas.
In response to this, the 2006 Assessment reports:
WCMP coordinated with the University of Wisconsin Sea Grant Institute to develop GIS and Web-based applications for supporting coastal management decision making. See here. Section 309 funds also supported a project that created digital terrain models and orthophotographs of a portion of western Bayfield County’s shoreline. Another project added a historic epoch (1966) of aerial photography for the estimation of recession rates in Bayfield County. The funds were also used to obtain oblique photos of the Bayfield County shoreline and to make the information available through the county’s Website. See here and here. Finally, 309 funds supported a multi-year project titled “Bluff and Wave Characterization of Lake Superior Coast.” The University of Wisconsin-Madison Geology and Geophysics Department coordinated the project, which is an initiative to characterize the bluff conditions of the Lake Superior coastline in order to help communities develop defensible setbacks. The WCMP recently extended funding for the project for a fifth year.
The Wisconsin Shoreline Inventory and Oblique Photo Viewer provides the results of shoreline inventories that were conducted along Wisconsin's Lake Michigan and Lake Superior shorelines in 1976-78 and in 2007-8. Data layers show photos, shore structures, beach protection and bluff condition.
Bayfield County Land Records Department has a variety of resources relating to shoreline erosion, including an interactive Web mapping application, MapViewer for Recession Analysis, to obtain information about Bayfield County's Lake Superior shoreline. You can determine existing bluff height, bluff parent material, bluff stable slope angle, and estimated shoreline recession rate. Also link to the Lake Superior Shoreland Erosion And Safe Building Setbacks site for information about Lake Superior erosion and how it may impact the development and maintenance of Lake Superior property. ShoreViewer allows you to explore Bayfield County's Lake Superior shore. Click on maps to view close range, oblique aerial photographs taken along the shoreline, or view bluff profile and erosion information collected by coastal researchers.
For more information on shoreline erosion, read the Quick Guide to Lake Superior Shoreline Erosion.
Although statewide erosion data does not exist, some counties such as Ozaukee County have erosion data. There is a 3D coastal erosion visual explaining Wisconsin’s bluff erosion in Ozaukee County.
Bluff erosion photos of the Wisconsin shoreline.
An informative article Lake Michigan coastal erosion and bluff failures appeared in bayviewcompass.com on January 30, 2011.
An article in Wisconsin’s Natural Resources magazine (June 2004) discusses the issues of bluff and beach erosion.
A discussion of the relationship between wave impact height and shoreline erosion of Lake Superior.
Wisconsin’s Sea Grant Coastal GIS Application Project discusses erosion issues.
The University of Wisconsin Sea Grant Institute, a partner to the Wisconsin Coastal Management Program, maintains a website with detailed information about coastal natural hazards in the Great Lakes. It provides a link to information on Great Lakes water levels. The Army Corps of Engineers also maintains a Web page on Great Lakes water levels.
The US Army Corps of Engineers has collected shoreline erosion data and compiled a recession rate database for the Lake Michigan shoreline.
Erosion problems at Atwater Beach, in the village of Shorewood.
The Heinz Center's Evaluation of Erosion Hazards, conducted for the Federal Emergency Management Agency (FEMA), studied the causes of coastal erosion hazards and proposed a variety of national and regional responses. The study, published in April 2000, concentrates on the economic impacts of erosion response policies as well as the cost of erosion itself to homeowners, businesses, and governmental entities.
A NOAA website that has graphs of sea level data for many coastal locations around the country over the last 40 to 50 years and projections into the future is Sea Levels Online.
NOAA Shoreline Website is a comprehensive guide to national shoreline data and terms and is the first site to allow vector shoreline data from NOAA and other federal agencies to be conveniently accessed and compared in one place. Supporting context is also included via frequently asked questions, common uses of shoreline data, shoreline terms, and references. Many NOAA branches and offices have a stake in developing shoreline data, but this is the first-ever NOAA Website to provide access to all NOAA shorelines, plus data from other federal agencies. The site is a culmination of efforts of NOAA and several offices within NOS (including NOAA’s Coastal Services Center, National Geodetic Survey, Office of Coast Survey, Special Projects Office, and Office of Ocean and Coastal Resource Management) and other federal agencies to provide coastal resource managers with accurate and useful shoreline data.
A related site launched in 2008 is NOAA Coastal Services Center's Digital Coast, which can be used to address timely coastal issues, including land use, coastal conservation, hazards, marine spatial planning, and climate change. One of the goals behind the creation of the Digital Coast was to unify groups that might not otherwise work together. This partnership network is building not only a website, but also a strong collaboration of coastal professionals intent on addressing coastal resource management needs. Website content is provided by numerous organizations, but all must meet the site’s quality and applicability standards. More recently, NOAA Coastal Services Center has developed a Sea Level Rise and Coastal Flooding Impacts Viewer as part of its Digital Coast website. Being able to visualize potential impacts from sea level rise is a powerful teaching and planning tool, and the Sea Level Rise Viewer brings this capability to coastal communities. A slider bar is used to show how various levels of sea level rise will impact coastal communities. Completed areas include Mississippi, Alabama, Texas, Florida, and Georgia, with additional coastal counties to be added in the near future. Visuals and the accompanying data and information cover sea level rise inundation, uncertainty, flood frequency, marsh impacts, and socioeconomics.
Erosion Contact Info
Federal Consistency Coordinator
Wisconsin Department of Administration
101 E Wilson St.
Madison, WI 53702
Phone: (608) 267-7988
Greg Breese, Shoreland Team Leader
- Vargas, A. and D. Hart, "Coastal Hazards", Wisconsin Great Lakes Chronicle 2002.
- Vargas, A. and D. Hart, "Coastal Hazards", Wisconsin Great Lakes Chronicle 2002.
|State of the Beach Report: Wisconsin