Chemical analyses of surface water in Illinois, 1975-77--Volume III, Ohio River tributaries and Mississippi River tributaries south of Illinois River basin

Agency. The results from water years 1975 to 1977 are presented in tabular form, and the history of sampling and analytical methods during that period are summarized. Stream discharge data from records of the U.S. Geological Survey are included for all sites where samples were collected at gaging stations or near enough that reliable discharge estimates could be made. The U.S. Geological Survey (USGS) maintains a network of stream-gaging stations in Illinois in cooperation with State, local, and other Federal agencies. Many of the stations sampled by IEPA and included in this report are at or near these gaging stations. Where possible, discharge values from USGS records have been added.