LOCATION.-- Lat 40°06'40", long 88°13'35" (NAD of 1927), in NW1/4NE1/4 sec.18, T.19 N., R.9 E., Champaign County, Hydrologic Unit 05120109, on right bank 300 ft. upstream from Mathews Ave., on University of Illinois campus in Urbana, and at mile 1.6.

DRAINAGE AREA.-- 4.46 mi², of which 0.88 mi² is noncontributing.

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: July 1948 to current year.

STAGE: Water years 1994 to current year.

PRECIPITATION: September 2003 to current year.

REVISED RECORDS.-- WDR IL-75-1: Drainage area. WDR IL-83-1: 1982(M). WDR IL-98: 1979-96 (selected events).

GAGE.-- Water-stage recorder, phone telemeter, acoustic-velocity meter, rain gage, and Parshall flume. Datum of gage is 694.00 ft. above NGVD of 1929 (693.88 ft NAVD 1988). Prior to Oct. 1, 1974, at datum 14.25 ft higher. From Oct. 1, 1974 to Sept. 30, 2001, at datum 14.10 ft. higher. From Apr. 19, 2002 to June 26, 2002, at site 95 ft. downstream at same datum. From June 27, 2002 to July 24, 2003 at site 250 ft. upstream at same datum.

REMARKS.-- Since Aug. 1, 1960, storm runoff from 0.88 mi² at headwaters has been diverted to Saline Branch through the Northwest Diversion Conduit. Prior to the 1970's, effluent from sewage-treatment plant about 0.5 mi upstream from gage. Since July 1999, a retention basin 1.0 mi upstream temporarily detains water during periods of heavy runoff. Water enters the retention basin by gravity flow during periods of heavy runoff, and is pumped out during the recession, with a maximum rate of 20 ft³/s not to exceed a maximum in-stream rate of 60 ft³/s. Since Oct. 1999, some temporary storage occurs in underground conduits 0.6 mi upstream during runoff events. Channel construction near this gage (03337000) began Aug. 30, 2001. Streamflow diversion pumpage for channel construction began Sept. 1, 2001 causing frequent fluctuations in stage. Channel construction and pumpage for channel construction ended May 6, 2003. PRECIPITATION: Collection, computation, and publication of precipitation data do not necessarily conform to standards used by the National Weather Service. Precipitation data could be subject to error for days with freezing and/or thawing of precipitation.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 946 ft³/s, from rating based on two indirect measurements, Aug. 12, 1993, gage height, 24.03 ft, present datum, from flood marks; minimum daily, 0.03 ft³/s, Feb. 12, 1981.

PRECIPITATION: Maximum daily total, 2.54 in, March 26, 2004.