LOCATION.-- Lat 40°01'29", long 90°37'54" (NAD of 1927), in SW1/4NE1/4 sec.33, T.1 N., R.2 W., Brown County, Hydrologic Unit 07130010, on deck of bridge on old U.S. Highway 24, 600 ft downstream from bridge on new U.S. Highway 24, 0.2 mi east of Ripley, 2 mi upstream from Town Branch, and at mile 12.3.

DRAINAGE AREA.-- 1,293 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: March 1921 to current year. Prior to October 1931, published as Crooked Creek at Ripley.

STAGE: Water years 1994 to current year.

SURFACE-WATER QUALITY

SEDIMENT: Water years 1981 and 1995-97.

CHEMICAL: Water years 1975-91.

SPECIFIC CONDUCTANCE: Water year 1979.

WATER TEMPERATURE: Water year 1979.

MISCELLANEOUS: Sediment concentration and particle size, water years 1995-97.

REVISED RECORDS.-- WSP 975: 1936. WSP 1208: 1925, 1929, 1933. WDR IL-75-1: Drainage area.

GAGE.-- U.S. Army Corps of Engineers water-stage recorder, satellite telemeter, and crest-stage gage. Datum of gage is 431.1 ft above NGVD of 1929. Prior to July 28, 1926, nonrecording gage at site 200 ft upstream at datum 0.02 ft higher. July 28, 1926 to Jan. 11, 1935, nonrecording gage at present site and datum.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 28,000 ft³/s, Mar. 7, 1985, gage height, 29.07 ft; maximum gage height, 29.15 ft, May 18, 1995, observed; no flow for part of Sept. 26, 1989.

SUSPENDED-SEDIMENT CONCENTRATIONS: Maximum daily, 7,140 mg/L, June 21, 1981; minimum daily mean, 5 mg/L, Dec. 4, 5, 1996.

SUSPENDED-SEDIMENT LOADS: Maximum daily, 212,000 tons, May 8, 1996; minimum daily, 0.87 tons, Jan. 20, 1997.

REMARKS FOR CURRENT YEAR.-- Records fair except those for estimated daily discharges, which are poor.

A - Estimated due to backwater from ice.

B - Gage height, 29.07 ft.

C - Observed.

Table of Contents

Introduction

Station Descriptions

Surface-Water Data

Ground-Water Data

Meteorological Data

Biological Data