USGS Water-Year Summary 2024
02234500 ST. JOHNS RIVER NEAR SANFORD, FL
LOCATION - Lat 28°50'16", long 81°19'28" referenced to North American Datum of 1927, in SW 1/4 sec.16, T.19 S., R.30 E., Seminole County, FL, Hydrologic Unit 03080101, near center of channel on bridge pile under U.S. Highway 17 and 92, at outlet of Lake Monroe, 4 mi northwest of Sanford, and 161 mi upstream from mouth.
DRAINAGE AREA - 2,582 mi².
SURFACE-WATER RECORDS
PERIOD OF RECORD - July 1932 to January 1933 and August 1941 to June 1956 (discharge measurements only), October 1964 to September 1968 (gage heights and miscellaneous discharge measurements only), May 1987 to September 1989, March 1995 to current year.
GAGE - Water-stage recorder, acoustic velocity meter, and data-collection platform. Datum of gage is at NGVD of 1929, prior to October 2005 datum of gage was .09 ft below NGVD of 1929 and 0.95 ft below NAVD of 1988.
COOPERATION - This gage is monitored in cooperation with the St. Johns River Water Management District.
EXTREMES OUTSIDE PERIOD OF RECORD - Maximum gage height since at least 1871, 13.37 ft, in fall of 1880, from information by Fred T. Williams, former city engineer for Sanford. Since July 1941, maximum daily gage height, 8.59 ft, Oct. 5-17, 1953, minimum daily, -0.43 ft, Apr. 5, 1945 (published as elevation for Lake Monroe near Sanford).
Maximum discharge (measured), 17500 ft³/s, Oct. 14, 1953.
WATER-QUALITY RECORDS
PERIOD OF RECORD - Water years 1954, 1956, 1962, 1965-71, 1974, 2000-2002.
SPECIFIC CONDUCTANCE: July 2000 to September 2002, December 2007 to September 2016 (discontinued).
WATER TEMPERATURE: July 2000 to September 2002, December 2007 to September 2016 (discontinued).
DISSOLVED OXYGEN: November 2010 to September 2016 (discontinued).
INSTRUMENTATION - Water-quality monitor and data-collection platform.
EXTREMES FOR PERIOD OF RECORD -
SPECIFIC CONDUCTANCE: Maximum, 2,660 µS/cm @ 25 °C, July 8, 2001; minimum, 320 µS/cm @ 25 °C, Sept. 2, 2008; maximum daily mean, 2,620 µS/cm @ 25 °C, July 8, 2001, minimum daily mean, 331 µS/cm @ 25 °C, Sept. 2, 2008.
WATER TEMPERATURE: Maximum, 35.9 °C, Aug. 6, 2011; minimum, 6.0 °C, Jan. 11, 12, 2010; maximum daily mean, 33.8 °C, Aug. 11, 2000; minimum daily mean, 9.0 °C, Jan. 5, 2001.
DISSOLVED OXYGEN: Maximum, 14.4 mg/L, Mar. 17, 2011; minimum, 0.2 mg/L, May 2, 3, 7, 2013; maximum daily mean, 11.00 mg/L, Feb. 1, 2016; minimum daily mean, 3.4 mg/L, Sept. 11, 2015.