“The Lake Michigan ravines of northeastern Illinois range from 10 to 75 feet in depth and extend as much as 2 miles inland from the lakeshore. The ravine systems are an important natural legacy, as they represent the only remaining natural drainage systems in the present-day Lake Michigan watershed in Illinois. Historically, almost 673 square miles of northeastern Illinois drained into Lake Michigan via the Chicago and the Calumet River systems and the coastal bluff/ravine systems (Map 1). By 1922, canals had diverted the majority of flow in both the Chicago and the Calumet River systems into the Des Plaines River watershed (within the Mississippi River basin) as a way to provide safe drinking water and alleviate flooding in the Chicago metropolitan area, and to allow for cargo traffic between the Great Lakes and the Mississippi River. The land area of Illinois currently draining to Lake Michigan covers only 88 square miles, or 12 percent of its extent at the time of Euro-American settlement. Of this remaining drainage area, over 50 square miles lie in Lake County, with ravines covering less than 1.6 square miles. The ravine systems are, therefore, both an important and uncommon resource for both Illinois and the Great Lakes watershed.”
Ravine Systems in the Lake Michigan Watershed, Illinois
More articles:
Coastal Erosion along the Illinois Coastal Zone
The Illinois Coast of Lake Michigan
Discovering the Benefits of On-site Stormwater Management
No comments:
Post a Comment