USGS Water-Year Summary 2024

05388250 Upper Iowa River near Dorchester, IA

LOCATION - Lat 43°25'16", long 91°30'31" referenced to North American Datum of 1927, in SE 1/4 SW 1/4 NW 1/4 sec.01, T.99 N., R.6 W., Allamakee County, IA, Hydrologic Unit 07060002, on downstream side of bridge on State Highway 76, 3.5 mi south of Dorchester, 650 ft upstream from Mineral Creek, 0.5 mi upstream from Bear Creek, and 18.3 mi upstream from mouth.

DRAINAGE AREA - 770 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD - Discharge measurements from September 1936 to September 1938, October 1939 to June 1975; discharge records from October 1938 to September 1939, July 1975 to current year.

GAGE - Water-stage recorder. Datum of gage is 659.80 ft above North American Vertical Datum of 1988. Prior to January 6, 1938, non-recording gage at site of old bridge, 0.2 mi upstream, at datum 5.91 ft higher; January 6, 1938, to April 26, 1948, non-recording gage at site of old bridge at datum 60.00 ft lower; April 27, 1948, to August 1963, non-recording gage at site of old bridge at same datum; August 1963 to June 1975, non-recording gage at same site and datum.

REMARKS - Accuracy of records is discussed in the annual Station Analysis archived at the USGS IA Water Science Center.

EXTREMES OUTSIDE PERIOD OF RECORD - Flood of May 31, 1941, reached a stage of 21.8 ft, from flood profile, discharge 30,400 ft³/s, on basis of slope-area determination of peak flow, at current datum.

WATER-QUALITY RECORDS

PERIOD OF RECORD - Water years 1975-1981.

PERIOD OF DAILY RECORD -
SPECIFIC CONDUCTANCE: Daily instantaneous values collected in conjunction with suspended-sediment samples, July 1975 to September 1981, records fragmentary.
WATER TEMPERATURE: Daily instantaneous values collected in conjunction with suspended-sediment samples, October 1977 to September 1981, records fragmentary.
SUSPENDED-SEDIMENT CONCENTRATION AND DISCHARGE: July 1975 to September 1981.