PROVISIONAL DATA SUBJECT TO REVISION

Station operated in cooperation with Portland General Electric.

STATION.--14209500  CLACKAMAS RIVER ABOVE THREE LYNX CREEK, OR,
LOCATION.--Lat 45° 07'30", long 122° 04'20", in NE 1/4 sec.21, T.5 S., R.6 E., 
Clackamas County, Hydrologic Unit 17090011, Mount Hood National Forest, on right 
bank 0.1 mi upstream from Three Lynx Creek, 0.25 mi downstream from powerplant, 
17 mi southeast of Estacada, and at mile 47.8.[location map]
DRAINAGE AREA.--479 mi2.
PERIOD OF RECORD.--April 1909 to December 1913, October 1921 to current year. 
Prior to October 1911 (monthly discharge only), published in WSP 1318.
REVISED RECORDS.--WSP 1148: Drainage area. WSP 1248: 1910(M), 1912, 1948-50(M).
GAGE.--Water-stage recorder. Datum of gage is 1,091.69 ft above NGVD of 1929 (levels 
by  Portland General Electric  Co.). Apr. 23, 1909, to Jan. 4, 1914, nonrecording 
gage at about same site and datum. Nov. 1, 1921, to Dec. 27, 1924, water-stage 
recorder at present site at datum 0.91 ft higher.
REMARKS.--Minor regulation since May 1956 by Timothy Lake (station 14208600).
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 68,200 ft3/s Dec. 22, 1964, 
gage height, 21.7 ft, from floodmark, from rating curve extended above 34,100 ft3/s 
on basis of slope-area measurement at gage height 15.06 ft; minimum recorded discharge, 
261 ft3/s Oct. 7, 1987; minimum daily, 410 ft3/s Sept. 4, 1986.

NOTE: River forecasts and additional data can be obtained at the 
National Weather Service's Advanced Hydrologic Prediction Services web page.

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