LOCATION.-- Lat 40°11'45", long 90°27'16" (NAD of 1927), in NE1/4 SE1/4 sec.36, T.3 N., R.1 W., Schuyler County, at bridge on US Highway 24, 1.3 miles southeast of Ray.

DRAINAGE AREA.-- 118 mi²

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

PARTIAL RECORD: Discharge measurements,Water year 1981.

SURFACE-WATER QUALITY

MISCELLANEOUS: Water year 1981.

BIOLOGICAL

BENTHIC MACROINVERTEBRATES: Water year 1997.

REMARKS.-- Station established as a low-flow water-quality sampling site in August 1997 as part of the National Water-Quality Assessment (NAWQA), Lower Illinois River Basin synoptic study.

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. Reach A begins 20 meters downstream from the US Route 24 bridge and continues downstream for 72 meters. The surface area sampled at reach A was 0.23 m².