USGS Water-Year Summary 2019
14013000 MILL CREEK NEAR WALLA WALLA, WA
LOCATION - Lat 46°00'29", long 118°07'03" referenced to North American Datum of 1927, in SW 1/4 SW 1/4 sec.07, T.6 N., R.38 E., Walla Walla County, WA, Hydrologic Unit 17070102, on left bank 0.1 mi downstream from Railroad Canyon, 4.0 mi downstream from City of Walla Walla diversion dam, 4.4 mi upstream from Blue Creek, 11.5 mi southeast of Walla Walla, and at mile 21.2.
DRAINAGE AREA - 59.6 mi².
- WSP 1398: 1946-48(M), 1950 (M). WSP 1935: 1959, drainage area.
PERIOD OF RECORD - August 1913 to September 1917, April to September 1938, October 1939 to September 1976, October 1979 to current year. Maximum discharge and occasional discharge measurements 1977-79.
GAGE - Water-stage recorder. Datum of gage is 1,995.85 ft above NGVD of 1929 (levels by U.S. Corps of Engineers). Prior to Oct. 1, 1938, nonrecording gages at about same site at different datums.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of Mar. 31 or Apr. 1, 1931, reached a discharge of about 11,000 ft³/s, based on slope-area measurement about 900 ft upstream at old City of Walla Walla diversion dam.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 6,350 ft³/s, Feb. 9, 1996, gage height, 20.43 ft, from rating curve extended above 1,600 ft³/s on basis of slope-area measurement of peak flow; minimum daily discharge, 9.5 ft³/s, Dec. 9, 10, 1972.