USGS Water-Year Summary 2024
12502500 AHTANUM CREEK AT UNION GAP, WA
LOCATION - Lat 46°32'10", long 120°28'20" referenced to North American Datum of 1927, in SE 1/4 SW 1/4 sec.08, T.12 N., R.19 E., Yakima County, WA, Hydrologic Unit 17030003, on right downstream wingwall of Union Pacific Railway bridge at Union Gap, 1.0 mi south of town of Union Gap, and at mile 0.6.
DRAINAGE AREA - 173 mi².
REVISIONS HISTORY - WSP 1933: Drainage area.
SURFACE-WATER RECORDS
PERIOD OF RECORD - May to November 1904, August 1907 to July 1908, March to October 1910, April 1911 to September 1914, May 1951 to April 1953, August 1960 to current year. Published as "near Yakima" 1904, 1907-08, 1910-12. Records for water years 1913-14 are published in WSP 1286.
GAGE - Water-stage recorder. Datum of gage is 943.560 ft above NAVD of 1988. Prior to Sept. 30, 1914, non-recording gage at approximately same site at various datums. May 12, 1951, to Sept. 30, 1972, water-stage recorder at present site at datum 3.00 ft higher.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 3,100 ft³/s, Jan. 16, 1974, gage height, 10.36 ft; maximum gage height, 13.5 ft, from high-water mark, backwater from Yakima River; no flow many days during September and October 1904.