LOCATION.--Lat 44° 57'30", long 116° 28'00" (NAD27), in NW1/4 sec.28, T.19 N., R.1 W., Adams County, Tamarack quad., Hydrologic Unit 17050124, a short distance upstream from outlet gates near left end of dam on Lost Creek, 4 mi west of Tamarack, at mile 10.3, and 16 mi north of Council.

DRAINAGE AREA.--29.4 mi².

PERIOD OF RECORD.--May to September 1924, May 1926 to September 1966, April 1980 to August 1982 (fragmentary) (discontinued).

GAGE.--Staff gage. Datum of gage is 4,748.8 ft above mean sea level (river-profile survey). Prior to May 1926, at datum 1.4 ft higher.

REMARKS.--Reservoir is formed by earth dam completed in 1910 and raised 6 ft in 1929. Permanent spillway crest is at gage height 22.26 ft; flashboard structure built in 1938 to permit storage to gage height 25.9 ft. Bottom of outlet tunnel is at gage height 1.46 ft, but natural flow through reservoir limits withdrawal below about gage height 2.8 ft. Water is used for irrigation of lands in Weiser River basin.

COOPERATION.--Gage readings furnished by Lost Valley Reservoir Co. or Watermaster for Water District 41.

EXTREMES FOR PERIOD OF RECORD.--Maximum gage height observed, 26.90 ft May 14, 1940, June 24, 1963; no storage at times in several years.