Most of Michigan's population depends on surface-water supply. The USGS, in cooperation with about 45 local, State, and Federal agencies, collects streamflow data at sites throughout the State. Long-term data from the USGS streamgaging network are used by various agencies to design bridges and culverts for predicted peakflows and for floodplain mapping to minimize flood damages. Hydroelectric utility operators, waste-water treatment plant operators, and the National Weather Service use streamflow data on a daily basis. Additionally, managers of fisheries and wildlife sanctuaries use USGS streamflow data during periods critical to maintaining suitable habitats for the fauna and flora they manage.
Major floods are infrequent in Michigan, but they can be severe.
The September 1986 flood in Michigan caused more than 400 million dollars in damages to homes, businesses, utilities, governmental structures, and harvest-ready agricultural crops. A 28-county area was declared a Federal disaster area. The USGS statewide stream-gaging network served a critical need during and after the 1986 flood. Flood stage and streamflow were measured at 23 stream gages in eight major river basins discharging to Lake Michigan and Lake Huron. Real-time data from USGS stream gages were used by the National Weather Service to forecast floods, which reduced economic losses in flooded areas.