LOCATION.-- Lat 41°36'25", long 87°35'52" (NAD of 1927), in NE1/4SE1/4 sec.15, T.36 N., R.14 E., Cook County, Hydrologic Unit 07120003, on left bank at downstream side of bridge on Cottage Grove Avenue in South Holland, 2.0 mi downstream from Thorn Creek, and at mile 23.0.

DRAINAGE AREA.-- 208 mi². (Does not include part of watershed diverted to Lake Michigan.)

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1947 to current year. Prior to October 1974, records published with those for streams in the St. Lawrence River basin (WSP 1307, 1727, 1911, 2111, WDR IL 1971-74).

STAGE: Water years 1994 to current year.

PRECIPITATION: October 2000 to current year.

REVISED RECORDS.-- WSP 1507: 1950, 1953. WDR IL-81-2: Drainage area.

GAGE.-- Water-stage recorder, phone telemeter, rain gage, and crest-stage gage. Datum of gage is 575.00 ft above NGVD of 1929 (Illinois Department of Transportation bench mark) (574.68 ft NAVD 1988). Prior to Oct. 27, 1947, nonrecording gage and Oct. 27, 1947, to Mar. 31, 1981, water-stage recorder at site 1.4 mi upstream at same datum. Apr. 14 to Nov. 8, 1981, nonrecording gage at same site and datum. Nov. 17, 1947, to Nov. 19, 1970, auxiliary water-stage recorder at Dixmoor, 4.7 mi downstream; prior to Nov. 17, 1947, nonrecording gage at the Dixmoor site read twice daily.

REMARKS.-- Flow from upper Little Calumet River is diverted to Lake Michigan by Burns ditch. Calumet Sag Channel, 6.6 mi downstream from station diverts the entire flow to the Mississippi River Basin.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 4,440 ft³/s, July 14, 1957, gage height, 20.11 ft, site then in use; maximum gage height, 20.50 ft, Nov. 28, 1990; minimum daily discharge, 7.9 ft³/s Oct. 6, 1950.

PRECIPITATION: Maximum daily total, 2.32 in., May 11, 2002 and Nov. 18, 2003.

EXTREMES OUTSIDE PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Flood of Apr. 6, 1947, reached a stage of 19.24 ft, from floodmarks, discharge, 4,760 ft³/s.