LOCATION.-- Lat 40°49'42", long 88°34'29" (NAD of 1927), in SW1/4 sec.6, T.27 N., R.6 E., Livingston County, Hydrologic Unit 07130002, at county road bridge, 0.3 mi. east of McDowell, 0.4 mi. downstream from Turtle Creek, 7.3 mi downstream from confluence of North and South Branches, and at mile 68.4.

DRAINAGE AREA.-- 551 mi²

PERIOD OF RECORD.--

SURFACE-WATER QUALITY

CHEMICAL: Water years 1978-91.

BIOLOGICAL

ALGAE: Water year 1997.

BENTHIC MACROINVERTEBRATES: Water year 1997.

REMARKS.--Water-discharge records from the Vermilion River at Pontiac (Station 05554500) were used to estimate mean daily discharges for this station. Station established as a low-flow water-quality samping site in August 1997 as part of the National Water-Quality Assessment (NAWQA), Lower Illinos River Basin synoptic study.