Thornapple Environmental Issues This site has a great deal of good information about the environmental issues that face all our Michigan rivers as well as the Thornapple River.
Michigan Chapter of the Sierra Club (Mackinac) -The Sierra Club is a nonprofit, member-supported public interest organization that promotes conservation of the natural environment by influencing public policy decisions: legislative, administrative, legal, and electoral.
River Network - a national river conservation organization dedicated to helping people save rivers and watersheds.
American Rivers - aims to protect and restore North America's river systems and to foster a river stewardship ethic.
League of Women Voters of Michigan