PROVISIONAL DATA SUBJECT TO REVISION

LOCATION.--Lat 42° 52'18", long 112° 28'05", in SE1/4 NW1/4 sec.27, 
T.6 S., R.34 E., Bannock County, Hydrologic Unit 17040208, on left bank 
1,400 ft downstream from Carson Street Bridge at Pocatello, 1.2 mi 
upstream from Pocatello Creek, and at mile 16.8.

DRAINAGE AREA.--1,250 mi2, approximately. Mean elevation, 5,850 ft.

PERIOD OF RECORD.--May to September 1897, March 1898 to October 1899, 
August 1911 to current year.

REVISED RECORDS.--WSP 1567: Drainage area.

GAGE.--Datum of gage is 4,418.41 ft above NGVD of 1929 (U.S. Army Corps of 
Engineers datum). May 18, 1897 to Oct. 14, 1899, nonrecording gage at 
site 1.6 mi upstream at different datum. Aug. 31, 1911 to May 13, 1927, 
and Oct. 13, 1927 to June 13, 1928, nonrecording gage 0.3 mi upstream 
at different datum. May 14 to Oct. 12, 1927, water-stage recorder near 
present site at different datum. June 14, 1928 to Sept. 28, 1950, 
water-stage recorder near Carson Street Bridge, 0.3 mi upstream at 
same datum as former nonrecording gages at this site. Sept. 29, 1950 
to May 20, 1968, water-stage recorder at Fremont Street site, 1.0 mi 
upstream at datum 18.57 ft higher.

REMARKS.--Flow regulated by Portneuf Reservoir, an earthen dam completed 
in 1912 and raised 7 ft in 1950; capacity, 23,695 acre-ft (capacity prior 
to 1950, 16,410 acre-ft); and Chesterfield Reservoir, capacity, 685 acre-ft. 
Diversions above station for irrigation of about 55,000 acres, of which about 
13,000 acres are irrigated by withdrawals from ground water (1966 determination).

EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 2,990 ft3/s Feb. 14, 1962, 
gage height, 11.35 ft, site and datum then in use; 
maximum gage height, 14.56 ft, Jan. 21, 1987, backwater from ice; 
minimum daily, 0.23 ft3/s July 19, 1979.

Station operated in cooperation with Idaho Department of Water Resources.