LOCATION.--Lat 42° 35'40", long 114° 31'46" (NAD27), in SW1/4 SE1/4 SW1/4 sec.36, T.9 S., R.16 E., Twin Falls County, Hydrologic Unit 17040212, Filer quad., 420 ft downstream from Poleline Road bridge, 3 mi upstream from mouth, and 4 mi northwest of Twin Falls.

DRAINAGE AREA.--297.4 mi², revised.

PERIOD OF RECORD.--July 1922 to September 1947, March 1983 to September 1990 (discontinued). Monthly and yearly discharge for 1922-47 published in WSP 1317. Published as "Rock Creek near mouth, near Twin Falls" (sta 13093095) at site 2 mi downstream, July 1975 to December 1982. Records equivalent except during irrigation season when irrigation-return flow may be significant.

GAGE.--Water-stage recorder. Datum of gage is 3,482.46 ft above NGVD of 1929. Prior to July 31, 1922, staff gage, and Sept. 30, 1947 to July 31, 1975, water-stage recorder, 100 to 300 ft upstream at various sites and at different datums.

REMARKS.--Flow regulated by many diversions upstream for irrigation and irrigation-return flows.

EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 984 ft³/s Sept. 21, 1927, gage height, 4.5 ft, from floodmarks, datum then in use; minimum, 63 ft³/s Jan. 30, 31, Feb. 9, 1985, gage height, 8.75 ft.