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Flood Monitoring

The Great Lakes Hydraulics and Hydrology Office monitors potential inland river flooding year round and potential flooding on the connecting channels of the Great Lakes (St. Marys River, St. Clair River, and Detroit River) due to ice jams. The general mission is to prevent and/or minimize loss of life and property damage caused by river/connecting channel flooding. The main focus of the mission is vigilant, on-going monitoring and advanced notification to emergency managers in regard to forecasted inclement weather and ice conditions potentially causing floods.


Ice jams have been a common occurrence throughout the history of the Detroit District. Fortunately, only a few have resulted in serious flooding. The main focus of ice jam monitoring is a series of water level gages strategically set up in the connecting channels to pinpoint the location of such a jam. Typically, when an ice jam begins to form, the water level upstream of the jam begins to rise and the water level downstream begins to fall, a classic divergence. The Detroit District office has near real-time access to gage data and, when such a ‘divergence’ occurs, can notify emergency managers who in turn notify the U.S. Coast Guard to break ice to alleviate potential flooding. Many of the primary tools the Detroit District uses to monitor ice conditions in the Great Lakes can be found on the following Web sites:

Additional information can also be found at the following web sites:

The Detroit District also monitors Snow Water Equivalent (SWE) to aid flood monitoring and Great Lakes water levels forecasting.



Drought conditions are monitored because they directly relate to the supply of water to lakes and rivers within the area of concern. Knowing the amount of moisture in the soil and the type of soil in the area aids in more accurate forecasts of how fast or slow runoff will occur into rivers. This is critical in forecasting the timing and extent of floods. The Detroit District monitors the National Weather Service’s (NWS) National Drought Assessment page.



Corps of Engineers Districts are charged with the responsibility of monitoring rivers and lakes within district boundaries in order to minimize or prevent flood damages. Flood monitoring of rivers located within the Detroit District is done using the River Conditions NWS Web site. By clicking on the map you will be taken to the corresponding regional page where USGS gages are represented by color coded squares on a map. Clicking on any gage location will display a hydrograph depicting how the river level has changed over time for that specific location.



Monitoring of current weather conditions and weather forecasts gives advanced notification of potential flooding. Hazardous weather outlooks and forecasts give vital information on the amounts of precipitation, wind intensity and direction, time and extent, etc. Thus, the severity of potential flooding can be assessed and prepared for effectively. The National Weather Services’ web pages are used to monitor inclement weather. These pages include Warning and Forecast, Hazardous Weather Outlooks, Severe Weather Outlooks, Special Weather Statements, Gale Warnings, Marine Weather Statements, and other pertinent weather information. By clicking on the map, detailed weather information is retrievable by geographic region.