PROVISIONAL DATA SUBJECT TO REVISION

Station operated in cooperation with the Bureau of Reclamation and the U.S. Army Corps of Engineers.

STATION.-- 14203500 TUALATIN RIVER NEAR DILLEY, OR

LOCATION.--Lat 45°28'30", long 123°07'23", in NE 1/4 NW 1/4 sec.24, T.1 S., R.4 W., 
    Washington County, Hydrologic  Unit 17090010, on left bank 5 ft upstream from highway
    bridge, 1.0  mi south of Dilley, 1.2 mi downstream from  Scoggins Creek, and at mile 
    58.8.[location map] 
DRAINAGE AREA.--125 mi2. 
PERIOD OF RECORD.--October 1939 to current year. Prior to October 1940 monthly discharge 
    only, published in WSP 1318. 
GAGE.--Water-stage recorder. Datum of gage is 147.57 ft above NGVD of 1929. Prior to 
    June 16, 1950, nonrecording gage at several sites within 200 ft of present site at datum 
    4.00 ft higher. June 16, 1950, to Aug. 10, 1966, water-stage recorder at present site at 
    datum 4.00 ft higher. 
REMARKS.--Diurnal fluctuation caused by operation of millpond on Scoggins Creek 
    upstream from station and regulation by Henry Hagg Lake since January 1975. Diversions 
    upstream from station of approximately 3,000 acre-ft from J. W. Barney Reservoir on 
    the Middle Fork of North Fork Trask River for municipal water supply and irrigation 
    in Wapato Lake area. Continuous water-quality records for the period November 1963 to 
    September 1968 have been collected at this location. US Geological Survey satellite 
    telemeter at station. 
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 17,100 ft3/s Dec. 22, 1964, gage height, 
    19.34 ft, from rating curve extended above 6,000 ft3/s; minimum discharge, 0.08 ft3/s 
    Sept. 3, 1967.

NOTE: The most current shifted rating for this site can be found at USGS Rating Depot website.