PROVISIONAL DATA SUBJECT TO REVISION

Station operated in cooperation with the Nez Perce Tribal Executive Committee with additional funding provided by the U.S. Geological Survey National Streamflow Information Program (NSIP).

STATION.-- 13292000  IMNAHA RIVER AT IMNAHA, OR 

LOCATION.--Lat 45° 33'45", long 116° 50'00", in SW 1/4 sec.16, T.1 N., R.48 E., Wallowa 
    County, Hydrologic Unit 17060102, on left bank at Imnaha, 0.3 mi downstream from Big Sheep 
    Creek,and at mile 19.3. [location map]
DRAINAGE AREA.--622 mi2. 
PERIOD OF RECORD.--June 1928 to current year.
REVISED RECORDS.--WSP 833: 1938. WSP 1397: 1929, 1932(M), 1949. WSP 1737: Drainage area. 
GAGE.--Water-stage recorder.  Datum of gage is 1,941.14 ft above NGVD of 1929. Prior to 
    Aug. 6, 1934, nonrecording gage at site 0.25 mi upstream at different datum. 
    Aug. 6-31, 1934,  nonrecording gage at present site and datum. 
REMARKS.--No regulation.  Diversions for irrigation upstream from station. Water is diverted 
    from Big Sheep Creek and tributaries upstream from station for irrigation in Wallowa River 
    basin. National Weather Service satellite telemeter at station.  Continuous water-quality 
    records for the period August 1965 to September 1968 and from May 1976 to September 1977 
    have been collected at this location.   
EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 20,200 ft3/s Jan. 1, 1997, gage height, 
    11.44 ft, from rating curve extended above 7,900 ft3/s, on basis of slope-area
    measurement of peak flow; minimum discharge observed, 16 ft3/s Nov. 22, 1931, result of 
    freezeup. 

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