USGS Water-Year Summary 2024

07022000 MISSISSIPPI RIVER AT THEBES, IL

LOCATION - Lat 37°13'17.76", long 89°27'46.71" referenced to North American Datum of 1983, in sec.17, T.15 S., R.3 W., Alexander County, IL, Hydrologic Unit 07140105, Thebes, Illinois, 5.0 mi downstream from Headwater Diversion Channel, and at mile 44.0 above Ohio River. Located on the property of one Mr. Wright, adjacent to a rip-rap berm approximately 700 feet upstream of the City of Thebes boat ramp. The river orifice tube is inside a 2 inch diameter, steel pipe running across and down the rip-rap berm into the water where the end is secured to an 800 pound, concrete, mooring anchor.

DRAINAGE AREA - 713,200 mi².

REVISIONS HISTORY - WSP 1341: 1844(M). WDR MO-76-1: Drainage area, WDR MO-98-1: Extreme outside period of record.

SURFACE-WATER RECORDS

PERIOD OF RECORD - DISCHARGE: Oct 1932 to current year. Monthly discharge only for some periods, published in WSP 1311. Prior to Apr 1941, published as "at Cape Girardeau, Mo". GAGE HEIGHT: Mar 1933 to Feb 1938 and Oct 1939 to current year. Prior to Apr 1941, published as "at Cape Girardeau, Mo". Since Nov 1878, under name of "at Grays Point" in files of the U.S. Army Corps of Engineers; Jan 1879 to May of 1896, published as "at Grays Point"; since May 1896, published as "at Cape Girardeau" in reports of the Mississippi River Commission; Feb 1891 to Feb 1894 and since 1904, published as "at Cape Girardeau" in reports of the National Weather Service.

REVISED RECORDS - WSP 1341: 1844(M). WDR MO-76-1: Drainage area, WDR MO-98-1: Extreme outside period of record.

GAGE - Water-stage recorder. Datum of gage is 299.70 ft above North American Vertical Datum of 1988. Mar 17, 1933, to Dec 21, 1934, nonrecording gage; Dec 22, 1934, to Apr 4, 1941, water-stage recorder, at site 8.2 mi upstream at datum 4.65 ft higher; Apr 5, 1941, to Sep 30, 1941, nonrecording gage at present site and datum; Oct 1, 1941, to Oct 11, 1943, at datum 0.07 ft higher. Prior to Apr 5, 1941, various auxiliary gages used. Since Oct 1, 1943, former gage at Cape Girardeau used as auxiliary gage.

REMARKS - Accuracy of records is discussed in the annual Station Analysis archived at the USGS MO Water Science Center.   Natural flow of stream affected by many reservoirs and navigation dams in the upper Mississippi River Basin and by many reservoirs and diversions for irrigation in the Missouri River Basin.

EXTREMES OUTSIDE PERIOD OF RECORD - Flood of Jul 4, 1844, reached an elevation of 345.14 ft, present datum, at Grays Point, from floodmarks, discharge, 1,075,000 ft³/s, computed by the U.S. Army Corps of Engineers.

WATER-QUALITY RECORDS

PERIOD OF RECORD - Jan 1973 to current year.

PERIOD OF DAILY RECORD - WATER TEMPERATURE: Oct 1974 to Sep 1981. SPECIFIC CONDUCTANCE: Oct 1974 to Sep 1981. SUSPENDED-SEDIMENT: Oct 1980 to current year.

REMARKS - National Stream-Quality Accounting Network (NASQAN) station Jan 1973 to Sep 1986. Illinois Environmental Protection Agency station Oct 1986 to Sep 1994 (during this period, samples were analyzed by the Illinois EPA). Re-established as a NASQAN station Oct 1994 to current year. Suspended-sediment station 1980 to current year. For water year 2016, sediment records good, except for estimated days which are fair.

EXTREMES FOR PERIOD OF DAILY RECORD - WATER TEMPERATURE: Maximum daily, 31.5 °C, Jul 10, 11, 1975, and Jul 17, 1977; minimum daily, 0.0 °C, on several days during winter periods. SPECIFIC CONDUCTANCE: Maximum daily, 705 microsiemens per centimeter, Aug 5-7, 1980; minimum daily, 272 microsiemens per centimeter, Apr 6, 1979. SUSPENDED-SEDIMENT CONCENTRATION: Maximum daily, 3,890 mg/L, Dec 22, 1985; minimum daily, 13 mg/L, Jan 28, 1981. SUSPENDED-SEDIMENT DISCHARGE: Maximum daily, 6,280,000 tons, Mar 1, 1985; minimum daily, 2,530 tons, Jan 28, 1981.