LOCATION.-- Above dam, lat 41°40'54", long 88°00'09" (NAD of 1927), in NW1/4 sec. 20, T. 37 N., R.11 E., Cook County, Hydrologic Unit 07120004, at Stephens Street Bridge, 0.2 mi north of Lemont and 11 mi upstream from confluence with Chicago Sanitary and Ship Canal. | |
DRAINAGE AREA.-- 687 mi2. | |
PERIOD OF RECORD.-- | |
SURFACE-WATER DISCHARGE AND STAGE | |
DISCHARGE: November 1914 to September 1944. | |
GAGE.-- Wire-weight gage. Datum of gage is 583.67 ft above NGVD of 1929. | |
REMARKS.-- During high water part of flow spills into Chicago Sanitary and Ship canal at Willow Springs, 7 mi above station, and (since February 1941) at two additional points 1 mi and 1.2 mi above station. This flow is not included in daily discharge. | |
EXTREMES FOR PERIOD OF RECORD.-- | |
SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 5,520 ft3/s Mar. 18, 1919; no flow for many days. | |