LOCATION.--Lat 43° 31'04", long 114° 19'11"(Rev.)(NAD83), in SE1/4 sec.9, T.2 N., R.18 E., Blaine County, Hailey quad., Hydrologic Unit 17040219, on left bank 25 ft upstream from county road crossing, 0.2 mi southwest of Hailey, and 0.2 mi northeast of Big Wood River.

PERIOD OF RECORD.--June 1915 to November 1973. Data for "Big Wood Slough" and "Big Wood River at Hailey" (sta 13139500) published separately for water years 1915 to 1965. Starting 1966 water year flows published as station 13139510 "Big Wood River and Big Wood Slough combined discharge at Hailey, Idaho".

GAGE.--Water-stage recorder. Datum of gage is 5,301.17 ft above NGVD of 1929, unadjusted. Prior to Apr. 12, 1936, staff gages at or near highway bridge, at present datum.

REMARKS.--Flow controlled at inoperative powerplant 0.5 mi upstream to meet the requirements of irrigation diversion and sewage dilution. Big Wood Slough is a natural channel of Big Wood River and its discharge plus the discharge of Big Wood River at Hailey (sta 13139500) is total discharge of river at this point.

EXTREMES FOR PERIOD OF RECORD.--Maximum discharge observed, 419 ft³/s June 6, 1921, from rating curve extended above 280 ft³/s; maximum gage height, 5.55 ft (top of ice in well), Jan. 20-23, 1937; no flow at times in several years.