Bedrock geology: digitized from the 1987 Michigan Bedrock Geology map from the Michigan Geological Survey; Milstein, Randall, 1987, Bedrock Geology of Southern Michigan: Michigan Department of Natural Resources, Michigan Geological Survey, Geological Publication BG-01, scale 1:500,000. Reed, Robert C., and Daniels, Jennifer, 1987, Bedrock Geology of Northern Michigan: Michigan Department of Natural Resources, Michigan Geological Survey, Geological Publication BG-01, scale 1:500,000.Midcontinent Rift: Areas underlain by rifting in the midcontinent approximately 1.1 billion years ago. John Esch, 2011, unpublished map. For more information, visit Michigan.gov/EGLE/Maps-Data/GeoWebFace or contact EGLE-GeoWebFace@michigan.gov.Field NameField DescriptionsOBJECTIDESRI ID NumberFormationCodeFormation codeFormationNameFormation name

Dams in Michigan are regulated by Part 307, Inland Lake Levels, and Part 315, Dam Safety, of The Natural Resources and Environmental Protection Act, 1994 PA 451, as amended. There are 2,500+ dams in the state, most of which are regulated by Part 315. Dams are regulated by Part 315 when they are over 6 feet in height and over 5 acres are impounded during the design flood. Dams are regulated by Part 307 when a circuit court issues an order establishing the level at which the lake is to be maintained. There are also 99 hydroelectric dams in Michigan that are regulated by the Federal Energy Regulatory Commission (FERC) under the Federal Power Act. The Dam Safety Program is responsible for ensuring the safety of Michigan's state regulated dams. These dams, owned by both public and private entities, are located throughout the state. The program focuses on ensuring that dams are properly constructed, inspected and maintained, and that the owners have adequately prepared for potential emergencies. Learn more at www.mi.gov/damsafety.This data is updated automatically by the Dam Safety Program as information changes.