USGS Water-Year Summary 2024
14138900 NORTH FORK BULL RUN RIVER NEAR MULTNOMAH FALLS, OR
LOCATION - Lat 45°29'40", long 122°02'05" referenced to North American Datum of 1927, in SE 1/4 SW 1/4 sec.11, T.1 S., R.6 E., Multnomah County, OR, Hydrologic Unit 17080001, Mount Hood National Forest, on left bank, 7.0 mi southeast of Multnomah Falls and at mouth.
DRAINAGE AREA - 8.32 mi².
REVISIONS HISTORY - WDR OR-91-1: 1976.
SURFACE-WATER RECORDS
PERIOD OF RECORD - August 1965 to current year.
GAGE - Water-stage recorder and crest-stage gage. Elevation of gage is 1,065 ft above NAVD of 1988, from digital elevation model. Prior to Oct. 1, 1978 and June 13, 1989 to Sept. 30, 1990 (during bridge construction), at site 700 ft upstream at datum 18.7 ft higher. Oct. 1, 1978 to June 12, 1989, at present site and datum.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 9,700 ft³/s Jan. 20, 1972, probably affected by surge from release of water temporarily impounded by landslide upstream from station, gage height, 9.89 ft, from floodmark, site and datum then in use, from rating curve extended above 850 ft³/s on basis of estimate of peak flow from slope-area survey; minimum discharge, 7.52 ft³/s Sept. 5, 2019.
WATER-QUALITY RECORDS
PERIOD OF DAILY RECORD -
SPECIFIC CONDUCTANCE: October 1978 to current year.
pH: October 1980 to September 1981, August 1990 to September 1992.
WATER TEMPERATURE: October 1978 to current year.
TURBIDITY: October 1990 to September 1994.
SUSPENDED SEDIMENT DISCHARGE: October 1978 to September 1986.
INSTRUMENTATION - Water-quality monitor.
EXTREMES FOR PERIOD OF DAILY RECORD -
SPECIFIC CONDUCTANCE: Maximum, 103 microsiemens Jan. 13, 1981 (result of cement spill); minimum, 6 microsiemens Jan. 12, 13, 2021.
pH: Maximum recorded, 9.8 units Jan. 13, 1981 (result of cement spill); minimum recorded, 6.3 units June 19, 1981.
WATER TEMPERATURE: Maximum, 15.5°C June 28, 2021; minimum, -0.2°C Dec. 20, 2008.
TURBIDITY: Maximum recorded, 25 NTU Nov. 24, 1990; minimum recorded, 0.06 NTU Sept. 7, 13, 14, 1992.
SEDIMENT CONCENTRATION: Maximum daily, 205 mg/L Dec. 25, 1980; minimum, 0 mg/L on many days.
SEDIMENT DISCHARGE: Maximum daily, 765 tons Feb. 23, 1986; minimum, 0 ton on many days.