This compilation of links and materials is meant to serve as a reference for Great Lakes Sea Grant Network staff and partners to assist in their community outreach related to water level fluctuations in the region. It is not intended to be comprehensive nor to serve as official communication on any issues mentioned below. Please contact the appropriate agency with any specific questions or data requests.

General Information

Explanation of water level data

  • Water levels are reported as an elevation above sea level (not a depth).
  • Levels are referenced to the International Great Lakes Datum of 1985. (Note: IGLD 1985 is due to be updated).
  • Lake Michigan and Lake Huron are viewed as one lake (from a hydrological standpoint).
  • Water levels are based on still water conditions, and do not take meteorological forcing – such as those that create seiches (see figures below) – into account.
  • Daily reported levels are based on a network of water level gauges operated by NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS) and the Canadian Hydrographic Service.
  • Official coordinated lake-wide mean water level data sets and statistics are provided by the US Army Corps of Engineers (USACE) in conjunction with Environment and Climate Change Canada (ECCC).
  • Detroit District of the USACE is the keeper of the official monthly water level statistics from 1918-2019.

Impacts of high water levels

  • Shoreline erosion
  • Increased sediment transport in the nearshore zone
  • Alterations to stream and river mouths
  • Damage to coastal infrastructure
  • Flooded marinas, docks, boat launches
  • Navigational hazards
  • Shrinking beaches in areas often used for recreation
  • Increased impacts from storms
  • Increase in coastal wetland habitats associated with drowned river mouths; some wetland areas may experience erosion
1) Water levels when undisturbed
2) Wind pushes water toward one end of the lake.
3) The buildup of water sloshes back to the other end of the lake.

Diagrams showing the formation of a seiche (Images courtesy of NOAA).

Diagram of the seasonal variation in climate and weather variables and relative Great Lakes water levels. (Image courtesy of NOAA).
Diagram of typical seasonal variation in climate and weather in relation to relative Great Lakes water levels (Image courtesy of NOAA).

Data, products, and tools

(Arranged by associated organization; Use buttons to jump to sections below.)

U.S. Army Corps of Engineers (USACE)

Great Lakes High Water – Centralized compilation of USACE resources from around the region related to current high water level issues, such as links to water levels data, permit and emergency response information, and FAQs –

USACE Detroit District’s Great Lakes information website – Includes data and products related to regional water level data, water level forecasts, basin conditions, outflows, and associated update articles –

Official USACE updates on lake-wide average water levels and associated Great Lakes Water Levels forecasts –

USACE water level forecast products include:

  • Weekly Forecast
    • comes out every Thursday
    • forecasts out 1 month from that day
  • Monthly Forecast
    • released at the beginning of each month
    • forecasts out 6 months
  • Water Level Outlook
    • updated every 3 months
    • forecasts scenarios out 1 year
Graph of monthly mean lakewide average water levels (provided by US Army Corps of Engineers).
Example of a graph of monthly mean lakewide average water levels (USACE)

National Oceanic and Atmospheric Administration (NOAA)

Water Levels in the Great Lakes storymap – explores the science, history, & importance of water levels in the Great Lakes on an interactive platform (Released Nov 5, 2021)

NOAA and Great Lakes Water Levels fact sheet – links to all the NOAA products and services addressing Great Lakes water levels

NOAA Great Lakes Environmental Research Lab’s Great Lakes Water Levels website includes links to:

NOAA Lake Level Viewer – The maps in this tab show extent and relative depth of water from -6 below to +6 feet above average lake level. The water level maps are created by adding or subtracting 1 to 6 feet from the average water level. NOTE: The data in the maps do not consider natural processes such as erosion, subsidence, or future construction. Water extent is as it would appear on a calm day with no wind-driven waves or seiche effect. The data, maps, and information provided should be used only as a screening-level tool –

Great Lakes Levels Dashboard

Great Lakes Operational Forecast System (GLOFS) – NOAA automated model-based prediction system aimed at providing improved predictions (guidance) of water levels, water currents and water temperatures in the Great Lakes for the commercial, recreation, and emergency response communities. GLOFS generates hourly nowcast guidance (analyses) and four times daily forecast guidance (out to 30 hours) of total water level, current speed and direction, and water temperature for each of the Great Lakes.
The graphical products include 1) time series that depict the most recent nowcast and forecast guidance at a specific station along with the latest observations and 2) map animations that depict an aerial view of a particular variable across the lakes. The water level output from the numerical model used by GLOFS is adjusted to be relative to the low water datums of the International Great Lakes Datum, 1985 (IGLD 1985). In addition, in order to take into account seasonal changes in water level, a 7 day mean is calculated for each lake from observed water levels from NOAA’s National Ocean Service’s (NOS) National Water Level Observation Network (NWLON). This mean value is added along with the IGLD to the model’s water level predictions to obtain the predicted total water level which is displayed on the time series plots. –

NOAA/GLERL Great Lakes Coastal Forecasting System (GLCFS): Near real-time nowcasts and forecasts of winds, waves, currents, and water temps –
Note: GLCFS is similar to the GL Operational Forecast System mentioned above, but is an older version based on a different model. It has lower spatial resolution and will be sunsetted once GLOFS has been fully operationalized.

Other NOAA regional climate and meteorological resources:

Quarterly Climate Impacts and Outlook for the Great Lakes Region (NOAA’s National Integrated Drought Information System) – Spring 2019 (Released June 2019) –

National Weather Service

Other sources of real-time meteorological information (site-specific):

Current water level gauges (site-specific) operated by NOAA CO-OPs –

Map of water level gauges around Lake Erie

CoastWatch statistics page with associated with Great Lakes surface water temperatures and ice concentrations over time –  

Example graph of Lake Superior long term average ice concentrations as compared to 2019

International Joint Commission (IJC)

International Lake Ontario – St. Lawrence River Board (ILOSLRB) – main duty is to ensure that outflows from Lake Ontario meet the requirements of the IJC order. The Board also has responsibilities to communicate with the public about water levels and flow regulation, and work with the Great Lakes – St. Lawrence River Adaptive Management (GLAM) Committee to monitor and assess the performance of the Regulation Plan 2014 –

2017 & 2019 High Water Events – Special webpage of the ILOSLRB that has all materials related to the recent high water events in one place –

International Lake Superior Board of Control – responsible for regulating Lake Superior outflows and and control works of the St. Marys River –

Methods of Alleviating the Adverse Consequences of Fluctuating Water Levels in the Great Lakes-St. Lawerence River Basin (1993 Report)

FEMA (Federal Emergency Management Agency)

FEMA’s Great Lakes Coastal Information website – provides information about FEMA’s ongoing floodplain mapping work in the coastal areas adjacent to the Great Lakes –

FEMA’s Great Lakes Coastal Flood Study – storm and wind study of the Great Lakes basin for the purpose of updating the coastal flood hazard information and Flood Insurance Rate Maps (FIRM) for Great Lakes coastal communities –

FEMA’s Pending and Preliminary Flood Hazard Layer mapping application – (also known as the FEMA Flood Map Changes Viewer) includes the preliminary Changes Since Last FIRM, the Preliminary Map Comparison Tool, and the preliminary, pending, and official National Flood Hazard Layers –

Additional Informational Resources

Living with the Lakes: Understanding and Adapting to Great Lakes Water Level Changes (USACE and Great Lakes Commission, 1999)

Living on the Coast: Protecting Investments in Shore Property on the Great Lakes (USACE and University of Wisconsin Sea Grant Program, 2003)

The same beach during low (left) and high (right) water levels.
The same beach during low (left) and high (right) water levels. (Images from: Living on the Coast, USACE / WI Sea Grant 2003)

Presentations & Webinar Archives

screenshot from webinar

Lake Superior Water Levels and Coastal Impacts (Twin Ports Climate Conversation Series, 4/21/20)

screenshot from webinar

Presentation slides delivered by USACE (Keith Kompoltowicz, Chief of Watershed Hydrology, Detroit District) at the Michigan High Water Coordination Summit (2/10/20 in Lansing, MI)

Resources specific to a Great Lake, Sea Grant program, or state

Lower Great Lakes

(Information arranged by state)

New York & Lake Ontario

USACE Buffalo District page with links to information on high water levels for Lake Ontario –

Coastal Resilience Index (New York Sea Grant) – Includes collection of tools to visualize inundation for individual parcels of interest using predetermined water levels to bring awareness to infrastructure and services that may be at risk. Inundation layers are based on the elevation of static water using the highest quality elevation data available for each county.  Currently wave run up data are not readily available. As a result, the generated maps assume only flat water associated with lake levels, not stormwater drainage issues.
Lake Ontario Inundation Mapping ToolNYSG Press Release with links

2017 High Water Impact Survey (NYSG) – New York’s Lake Ontario region saw unprecedented high water levels in 2017. New York Sea Grant responded to stakeholder requests for a standardized means of reporting the water level damages on waterfront properties by awarding special funding to Cornell University to develop and conduct an online survey. Information and results available here –

2017 Lake Ontario Flood: A sample of results from the Lake Ontario Flood Impact Survey – An interactive story map highlighting 2017’s Lake Ontario Water Level Impacts

Pennsylvania & Lake Erie

Resources from the Community Resilience Action Network of Erie (CRANE). Includes:
Lake Erie Water Levels page with helpful infographics, news interviews about local water level impacts, and other information that local communities need to know –
– Lake Erie water temperature data and water level trends (based on U.S. EPA Climate Change Indicators) –

The “New Normal” for Agriculture & Climate in Erie County, 2017 Summit  –

Ohio & Lake Erie

Ohio Sea Grant-funded research – Early flood warning system for the Community Safety against Flood Hazard using High Resolution Datasets: A Case Study of Coastal Region of Lake county, Ohio (Youngstown State University – 2014) Project Summary

Upper Great Lakes

(Information arranged by state)


Michigan Sea Grant’s online collection of resources related to extreme storms and flooding – 

Michigan’s Great Lakes Shorelines Throughout Time – map viewer (BETA version) – 

Great Lakes Shoreline Viewer  – risk assessment and climate adaptation planning tool. It provides oblique-angle color photography plus multiple layers of additional analysis for prioritized sections of Great Lakes coastline in Michigan (Lake Superior, Lake Michigan, Lake Huron). It also provides potential risk rankings (high, medium, low) for coastal property, buildings, roads and infrastructure –

Michigan EGLE website on Great Lakes High Water Levels – Collection of permitting and technical resources available from the Department of Environment, Great Lakes, and Energy (EGLE) for property owners dealing with erosion –

Illinois/Indiana/Wisconsin & Lake Michigan

Informational Resources for Great Lakes Property Owners (WISG)

Southeastern Wisconsin Coastal Resilience project website – provides resources and assistance to communities in Ozaukee, Milwaukee, Racine, and Kenosha Counties to plan and prepare for coastal hazards like erosion, coastal storms and fluctuating water levels –
(Includes a blog with regular water level updates and a dynamic list of resilience resources)

Take 5: Great Lakes water levels with Adam Bechle (WI Sea Grant Blog Post – October 14, 2019)

Identification of sites at highest risk of flooding in Chicago and Milwaukee areas:
 – IISG article describing project
 – Products available on Midwestern Regional Climate Center website

Flood Vulnerability Assessment for Critical Facilities -Online tool to assist critical facilities (like hospitals, fire and police departments, and utility providers) evaluate their preparedness for when the next big rain storm hits. At the heart of the tool is a series of questions that will help communities in the Midwest determine a facility’s risk based on factors like its proximity to a flood plain, past flooding issues, stormwater drainage structures, and the location of backup generators, servers, and other critical systems.
 – About:
 – Tool:

Illinois-Indiana Sea Grant website on community resilience to climate change – includes links to tools for resiliency planning and vulnerability assessments –

Illinois – Indiana Sea Grant’s Stormwater@Home Video Series – teaches homeowners simple steps they can take to better manage stormwater on their property. The series gives tips and tricks to help avoid pooling in yards, flooding in basements and excess runoff flowing into local waterways –


Lake Superior’s Record-Long Stretch of High Water Ends (MNSG online article, Oct 2021)

Twin Cities

Metropolitan Council’s Climate Vulnerability Assessment  

Localized Flood Map Screening Tool

Lake Champlain

Lake Champlain Sea Grant is helping communities prepare for and respond to significant flooding events by assisting municipalities to identify infrastructure risks, and helping property owners to stabilize shorelines with bioegineering –