Illinois River Bluffs area assessment / Illinois. Dept. of Natural Resources. Office of Scientific Research and Analysis. Illinois. Dept. of Natural Resources. Critical Trends Assessment Project. Illinois State Geological Survey. text Springfield, Ill. : Illinois Dept. of Natural Resources, 1998- eng v. : 28 cm. "The Illinois River Bluffs Area Assessment examines an area in west-central Illinois that includes parts of the upper and lower Illinois River watersheds from the vicinity of Hennepin southward to East Peoria ... designated a state Resource Rich Area."--P. iii. "Critical Trends Assessment Program."--Cover. Includes bibliographical references. v. 1. Geology -- v. 2. Water resources -- v. 3. Living resources -- v. 4. Socio-economic profile. Environmental quality. Archaeological resources -- v. 5. Early accounts of the ecology of the Illinois River Bluffs Area. Natural resources conservation areas -- Illinois -- Illinois River Watershed. Natural resources surveys -- Illinois -- Illinois River Watershed. Illinois River Watershed (Ill.)