Water-Data Report 2009 12472800 COLUMBIA RIVER BELOW PRIEST RAPIDS DAM, WA Upper Columbia Basin Upper Columbia-Priest Rapids Subbasin

LOCATION.--Lat 46°3744, long 119°5149 referenced to North American Datum of 1927, in SE ¼ NW ¼ sec.7, T.13 N., R.24 E., Grant County, WA, Hydrologic Unit 17020016, on left bank 2.6 mi downstream from Priest Rapids Dam, 14.7 mi south of Beverly, and at mile 394.5. DRAINAGE AREA.--96,000 mi². SURFACE-WATER RECORDS PERIOD OF RECORD.--January 1917 to current year. January 1917 to September 1930, at site 3.4 mi downstream, published as "at Vernita." October 1930 to July 27, 1959, at site 46.5 mi upstream, published as "at Trinidad." REVISED RECORDS.--WSP 1933: Drainage area. WDR WA-82-2: 1965(m), 1971(m). GAGE.--Water-stage recorder. Datum of gage is NGVD of 1929. Prior to Oct. 1, 1930, nonrecording gages at site 3.4 mi downstream at datum 388.7 ft above sea level. Oct. 1, 1930, to July 27, 1959, water-stage recorder at site 46.5 mi upstream at datum 499.3 ft above NGVD of 1929 (river-profile survey). REMARKS.--Records good except estimated daily discharges and discharges below 70,000 cfs which are fair. Diversions for irrigation of about 600,000 acres upstream from station. Flow regulated by 10 major reservoirs and numerous smaller reservoirs and powerplants. U.S. Geological Survey satellite telemeter at station. Water temperatures March 1980 to April 1993. Temperature records for site "at Vernita Bridge, near Priest Rapids Dam" (station 12472900) for period July 1974 to September 1980 are equivalent. AVERAGE DISCHARGE FOR PERIOD OF RECORD.--92 years (water years 1918-2009), 118,400 ft³/s, 85,800,000 acre-ft/yr, unadjusted. 50 years (water years 1960-2009), 117,800 ft³/s, 85,370,000 acre-ft/yr, regulated period. EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 692,600 ft³/s, June 12, 1948, gage height, 59.35 ft, site and datum then in use; minimum discharge, 4,120 ft³/s, Feb. 10, 1932, due to construction at Rock Island Dam, site and datum then in use; minimum daily discharge prior to construction of Rock Island Dam (1932), 22,000 ft³/s, Feb. 1-7, 1930, site and datum then in use; minimum daily discharge after completion of Rock Island Dam (1932), 20,000 ft³/s, Jan. 31 to Feb. 10, 1937, site and datum then in use; minimum discharge since completion of Priest Rapids Dam (1959), 16,300 ft³/s, Nov. 7. 1998, due to emergency flow reduction from Priest Rapids Dam. EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of June 7, 1894, reached a discharge of about 740,000 ft³/s, based on a rating extension for a Weather Bureau gage at Wenatchee. EXTREMES FOR CURRENT YEAR.--Maximum discharge, 219,000 ft³/s, April 24, gage height, 412.73 ft; minimum discharge, 36,600 ft³/s, Oct. 2, gage height, 396.43 ft, minimum daily discharge, 38,900 ft³/s, Oct. 4.

U.S. Department of the Interior U.S. Geological Survey Water-Data Report 2009 12472800 COLUMBIA RIVER BELOW PRIEST RAPIDS DAM, WA—Continued

DISCHARGE, CUBIC FEET PER SECOND WATER YEAR OCTOBER 2008 TO SEPTEMBER 2009 DAILY MEAN VALUES [e, estimated] Day Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

1 61,600 63,400 112,000 73,700 88,400 63,500 111,000 139,000 165,000 95,100 99,500 50,800 2 68,000 63,600 74,800 65,700 70,900 63,400 66,000 116,000 148,000 76,700 71,600 89,500 3 48,600 72,100 119,000 116,000 98,200 62,700 63,800 108,000 189,000 76,700 76,000 43,600 4 38,900 76,000 120,000 95,700 104,000 62,600 63,400 81,100 189,000 74,700 95,300 52,400 5 41,800 92,200 120,000 138,000 77,100 62,500 61,600 106,000 182,000 84,100 85,800 42,300 6 55,700 66,600 84,700 113,000 70,400 67,000 61,600 107,000 173,000 106,000 98,500 53,600 7 55,500 77,900 64,700 102,000 64,500 62,900 62,800 66,800 162,000 140,000 100,000 52,200 8 65,700 83,900 79,900 89,300 68,400 62,100 65,000 95,200 181,000 131,000 62,300 76,200 9 68,600 73,600 98,500 96,200 91,500 63,300 73,200 122,000 183,000 127,000 53,100 64,600 10 63,600 83,400 74,300 98,400 110,000 62,900 104,000 119,000 175,000 143,000 76,000 54,000 11 55,000 82,900 107,000 65,700 131,000 69,000 110,000 124,000 161,000 120,000 88,500 58,400 12 42,000 96,100 86,100 100,000 105,000 68,700 103,000 130,000 156,000 120,000 89,900 39,800 13 69,700 114,000 71,500 107,000 78,300 62,300 118,000 141,000 132,000 120,000 62,400 39,400 14 86,600 75,500 126,000 123,000 82,500 62,000 108,000 129,000 129,000 118,000 52,900 41,000 15 68,700 57,000 96,600 131,000 66,800 62,100 139,000 125,000 139,000 111,000 49,100 56,200 16 88,300 53,200 103,000 142,000 69,900 64,500 129,000 126,000 100,000 107,000 49,200 45,300 17 97,500 68,400 104,000 138,000 69,300 86,200 138,000 112,000 121,000 115,000 82,800 62,500 18 64,100 66,000 123,000 124,000 70,500 92,300 134,000 128,000 153,000 86,100 82,500 64,700 19 45,200 99,600 130,000 115,000 81,000 80,900 133,000 119,000 168,000 85,200 98,300 45,200 20 70,900 102,000 111,000 141,000 84,900 62,800 123,000 127,000 151,000 86,700 e92,000 39,800 21 73,200 92,000 102,000 127,000 107,000 62,300 124,000 132,000 141,000 109,000 e85,000 48,500 22 78,400 75,100 99,700 126,000 74,000 61,700 127,000 125,000 157,000 100,000 e70,000 70,600 23 67,400 79,800 141,000 137,000 93,200 63,700 137,000 140,000 183,000 76,000 e50,000 68,700 24 75,600 85,100 101,000 105,000 91,600 63,400 162,000 144,000 172,000 98,100 e90,000 82,100 25 56,100 114,000 94,400 98,200 90,200 70,400 142,000 141,000 143,000 84,700 e89,000 71,700 26 53,700 107,000 98,200 148,000 103,000 96,900 141,000 140,000 148,000 91,400 e88,000 44,200 27 69,700 89,700 85,900 131,000 82,200 84,200 144,000 165,000 151,000 114,000 e86,000 50,400 28 69,600 85,200 86,700 125,000 64,000 113,000 159,000 180,000 144,000 120,000 81,000 76,200 29 75,700 68,500 103,000 128,000 --- 85,400 150,000 172,000 159,000 119,000 62,400 61,300 30 84,400 71,700 112,000 119,000 --- 92,800 137,000 161,000 143,000 104,000 57,800 56,400 31 68,800 --- 77,100 107,000 --- 90,600 --- 153,000 --- 119,000 69,600 --- Total 2,028,600 2,435,500 3,107,100 3,525,900 2,387,800 2,228,100 3,390,400 3,974,100 4,698,000 3,258,500 2,394,500 1,701,600 Mean 65,440 81,180 100,200 113,700 85,280 71,870 113,000 128,200 156,600 105,100 77,240 56,720 Max 97,500 114,000 141,000 148,000 131,000 113,000 162,000 180,000 189,000 143,000 100,000 89,500 Min 38,900 53,200 64,700 65,700 64,000 61,700 61,600 66,800 100,000 74,700 49,100 39,400 Ac-ft 4,024,000 4,831,000 6,163,000 6,994,000 4,736,000 4,419,000 6,725,000 7,883,000 9,318,000 6,463,000 4,749,000 3,375,000

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1918 - 2009, BY WATER YEAR (WY) Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Mean 72,370 74,560 79,290 82,300 82,420 83,090 105,200 188,900 259,200 192,300 118,700 81,110 Max 119,800 121,200 163,800 168,400 195,000 201,800 196,500 348,500 590,700 385,400 192,000 131,700 (WY) (1928) (1991) (1996) (1996) (1996) (1983) (1934) (1934) (1948) (1950) (1920) (1927) Min 45,950 32,290 26,840 21,710 20,900 26,500 37,160 61,840 78,810 56,650 66,740 56,720 (WY) (1932) (1937) (1937) (1937) (1937) (1937) (1944) (2001) (1977) (2001) (1985) (2009)

— 2 — Water-Data Report 2009 12472800 COLUMBIA RIVER BELOW PRIEST RAPIDS DAM, WA—Continued

SUMMARY STATISTICS Calendar Year 2008 Water Year 2009 Water Years 1918 - 2009 Annual total 39,694,500 35,130,100 Annual mean 108,500 96,250 118,400 Highest annual mean 165,600 1997 Lowest annual mean 78,070 1944 Highest daily mean 265,000 May 24 189,000 Jun 3 690,000 Jun 12, 1948 Lowest daily mean 37,200 Sep 21 38,900 Oct 4 20,000 Jan 31, 1937 Annual seven-day minimum 51,400 Sep 30 47,700 Sep 10 20,100 Jan 30, 1937 Annual runoff (ac-ft) 78,730,000 69,680,000 85,800,000 10 percent exceeds 196,000 142,000 224,000 50 percent exceeds 94,800 90,000 94,600 90 percent exceeds 62,600 58,200 47,600

1,000,000

500,000

200,000

100,000

50,000

MEAN DISCHARGE, CUBIC FEET PER SECOND MEAN DISCHARGE, CUBIC FEET PER SECOND 20,000

10,000 O N D J F M A M J J A S 2008 2009

— 3 —