USGS Water-Year Summary 2020
13073000 PORTNEUF RIVER AT TOPAZ, ID
LOCATION - Lat 42°37'29", long 112°05'17" referenced to North American Datum of 1983, in SE 1/4 sec.23, T.9 S., R.37 E., Bannock County, ID, Hydrologic Unit 17040208, Haystack Mountain quad., on right bank 200 ft upstream from Bob Smith Creek, 800 ft downstream from Topaz siding, 1.5 mi upstream from diversion dam of Portneuf-Marsh Valley Canal Co., 4 mi west of Lava Hot Springs, and at mile 55.5.
DRAINAGE AREA - 576 mi². includes that of Bob Smith Creek.
PERIOD OF RECORD - January 1913 to September 1915, July 1919 to current year. Monthly discharge only for some periods, published in WSP 1317.
GAGE - Water-stage recorder and crest-stage gage. Elevation of gage datum is arbitrary. Prior to July 20, 1919, non recording gage at site 0.3 mi. downstream at datum 3.0 ft. lower. July 20, 1919 to June 22, 1954, non recording gage at site 0.3 mi. downstream at datum 2.00 ft. lower than present datum.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 7,120 ft³/s Feb. 1, 1963, gage height, 8.22 ft, result of highway fill failure 2 mi. upstream.
Maximum discharge excluding highway fill failure events of 1962 and 1963, 1,740 ft³/s Dec. 23, 1964, gage height, 6.00 ft; minimum discharge, 25 ft³/s Sept. 17,18, 2012, gage height, 0.95 ft.