LOCATION.-- Lat 40°48'18", long 87°51'50" (NAD of 1983), in SW1/4 NW1/4 SW1/4 sec.20, T.27N., R.13W., Iroquois County, Hydrologic Unit 07120002, at State Route 49, north of Crescent City, and at mile 6.4.

DRAINAGE AREA.-- 244.6 mi².

PERIOD OF RECORD.--

BIOLOGICAL

BENTHIC MACROINVERTEBRATES: Water year 2005.

REMARKS.-- Biology station established in 2005 as part of a comparative study of the National Water-Quality Assessment (NAWQA) program and the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP) invertebrate sampling techniques.

REMARKS FOR CURRENT YEAR.--Benthic macroinvertebrate community samples were collected as part of a comparability study for the National Water-Quality Assessment program (NAWQA) in the upper Illinois River Basin. One quantitative (Richest-Targeted Habitat) and one qualitative (Qualitative-Multiple Habitat) sample were collected in accordance with the NAWQA protocols (Moulton and others, 2002). The quantitative sample was a composite of macroinvertebrates from about ten submerged tree branches. Branches were cut underwater, gathered in a 500µm 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. The qualitative sample was collected from many habitat types within the sampling reach to obtain as complete a list of invertebrate taxa as possible. 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 is located at State Road 49 crossing north of Crescent City. The surface area sampled was 0.21 m².