PROVISIONAL DATA SUBJECT TO REVISION

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

 STATION.-- 14128870  COLUMBIA RIVER BELOW BONNEVILLE DAM, OR

 LOCATION.--Lat 45° 38'00", long 121° 57'33", in sec.21, T.2 N., R.7 E., Multnomah County, 
     Hydrologic Unit 17080001, on left bank 0.9 mi downstream from Bonneville Dam left bank 
     powerhouse, 50 ft upstream from Tanner Creek, and at mile 144.5.[location map] 
 DRAINAGE AREA.--239,900 mi2, approximately. 
 PERIOD OF RECORD.--May 1981 to current year (gage heights only).
 GAGE.--Water-stage recorder.  Datum of gage is NGVD of 1929.  Prior to August 15, 1990, at a site 
     0.5 mi upstream at the same datum
 REMARKS.--Flow regulated by many reservoirs upstream.
 EXTREMES FOR PERIOD OF RECORD.--Maximum gage height, 35.11 ft. Feb. 9, 1996; minimum, 6.14 ft 
     July 15, 16, 2001.
 EXTREMES FOR FEBRUARY 1996 FLOOD.--Maximum gage height, 35.11 ft. Feb. 9, minimum, 8.26 ft 
     Oct. 1, 2.