LOCATION.-- Lat 41°21'57", long 89°29'54" (NAD of 1927), in SW1/4SE1/4 sec.18, T.16 N., R.9 E., Bureau County, Hydrologic Unit 07130001, on right bank 500 ft downstream from bridge on U.S. Highways 6 and 34, 0.6 mi downstream from Epperson Run, 1.5 mi west of Princeton, and at mile 20.5.

DRAINAGE AREA.-- 196 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: March 1936 to current year. Prior to October 1974, published as Bureau Creek at Princeton.

STAGE: Water years 1994 to current year.

SURFACE-WATER QUALITY

CHEMICAL: Water years 1978-91.

BIOLOGICAL: Benthic macroinvertebrates, water year 1997.

REVISED RECORDS.-- WSP 1175: 1940-41, 1948. WSP 1308: 1942(M). WDR IL-75-1: Drainage area.

GAGE.-- Water-stage recorder and U.S. Army Corps of Engineers satellite telemeter. Datum of gage is 555.39 ft above NGVD of 1929 (levels by U.S. Army Corps of Engineers). Prior to July 18, 1940, nonrecording gage at bridge 400 ft upstream at datum 30.00 ft lower. July 18, 1940, to Sept. 30, 1944, water-stage recorder at site 500 ft upstream at present datum.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 12,500 ft³/s, May 17, 1974, gage height, 16.01 ft, from rating curve extended above 11,800 ft³/s; no flow during January 1940 and for several days in October and November 1953.

REMARKS FOR CURRENT YEAR.--Benthic macroinvertebrate community samples were collected as part of the National Water-Quality Assessment program (NAWQA) in the lower Illinois River Basin. One quantitative (Richest-Targeted Habitat) sample was collected in accordance with the NAWQA protocols (Cuffney and others, 1993). The quantitative sample was a composite of macroinvertebrates from about 10 submerged tree branches. Branches were cut underwater, gathered in a 425µm mesh net, and invertebrates were washed or picked from the branches. The average length and average diameter of each branch were measured and used to calculate an approximate surface area. All samples were processed by the USGS National Water-Quality Laboratory. Phylum, Class, Order, Suborder, Family, Subfamily, and Tribe are listed and arranged according to the USGS National Water-Quality Laboratory taxonomic hierarchy. The reach begins downstream from the bridge at US Route 6/34, west of Princeton. The surface area sampled at reach A was 0.19 m².