Water-Data Report 2008 11363000 Pit River at Big Bend, CA Sacramento River Basin

LOCATION.--Lat 41°0110, long 121°5436 referenced to North American Datum of 1927, in NW ¼ SW ¼ sec.31, T.37 N., R.1 E., Shasta County, CA, Hydrologic Unit 18020003, on left bank at Big Bend, 0.4 mi downstream from Nelson Creek, 1.5 mi upstream from Kosk Creek, and 3.1 mi downstream from Pit No. 5 Dam. DRAINAGE AREA.--4,711 mi², excluding Goose Lake Basin. SURFACE-WATER RECORDS PERIOD OF RECORD.--October 1910 to current year. Monthly discharge only for some periods, published in WSP 1315-A. Published as "at Henderson" 1910-23. REVISED RECORDS.--WSP 1345: 1911, 1914 (instantaneous maximum discharge), 1916 (instantaneous maximum discharge), 1917, 1928, 1935-36 (instantaneous maximum discharge). WDR CA-75-4: Drainage area. GAGE.--Water-stage recorder. Datum of gage is 1,674.47 ft above NGVD of 1929. Prior to Dec. 28, 1912, nonrecording gage; Dec. 28, 1912, to June 21, 1924, water-stage recorder at same site, at datum 7.69 ft higher. June 22, 1924, to Sept. 30, 1988, at site 200 ft downstream at same datum. COOPERATION.--Records were collected by Pacific Gas and Electric Co., under general supervision of the U.S. Geological Survey, in connection with Federal Energy Regulatory Commission project no. 233. REMARKS.--Low flow completely regulated by many reservoirs and powerplants, total usable reservoir capacity, about 253,000 acre-ft. Many diversions upstream from station; diversion to Pit No. 5 Powerplant (station 11362700) began May 1, 1944. See schematic diagram of Pit and McCloud River Basins available from the California Water Science Center. EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 49,000 ft³/s, Jan. 25, 1970, gage height, 18.17 ft, in gage well, 19.0 ft, from floodmarks, site then in use, from rating curve extended above 17,000 ft³/s, maximum gage height, 18.70 ft, Feb. 20, 1986, site then in use; minimum daily, 692 ft³/s, July 9, 1925; minimum daily since diversion to Pit No. 5 Powerplant, 34 ft³/s, Mar. 29, 1955. PEAK DISCHARGES FOR CURRENT YEAR.--Peak discharges greater than base discharge of 6,000 ft³/s and (or) maximum (*):

Discharge Gage height Date Time (ft³/s) (ft) Jan 04 2245 *2,220 *8.93

U.S. Department of the Interior U.S. Geological Survey Water-Data Report 2008 11363000 Pit River at Big Bend, CA—Continued

DISCHARGE, CUBIC FEET PER SECOND WATER YEAR OCTOBER 2007 TO SEPTEMBER 2008 DAILY MEAN VALUES Day Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

1 177 175 191 194 239 339 295 290 229 197 184 188 2 175 180 191 193 238 321 287 284 220 194 179 192 3 170 183 191 204 252 507 288 284 224 196 182 195 4 173 182 190 581 243 360 293 288 223 192 182 184 5 175 175 189 842 232 306 295 289 224 194 177 189 6 172 176 189 304 231 294 291 291 218 190 181 192 7 163 183 198 281 229 428 289 285 208 195 179 193 8 160 182 207 273 228 575 287 289 208 190 175 190 9 173 177 201 251 226 573 287 287 212 186 174 186 10 197 172 195 277 225 705 284 280 207 184 175 185 11 180 177 195 280 226 800 286 279 207 185 174 187 12 184 180 193 267 234 804 291 271 205 184 170 181 13 182 171 183 258 234 1,030 302 266 205 183 172 182 14 171 167 190 247 233 1,160 307 269 205 186 174 183 15 172 180 192 246 230 1,330 315 270 201 192 184 184 16 211 182 191 241 229 1,490 300 267 200 190 176 183 17 201 186 203 235 233 1,330 298 266 196 187 176 188 18 177 188 253 231 231 1,190 300 254 199 176 171 190 19 303 198 267 228 234 1,230 301 248 198 180 171 187 20 215 182 293 226 237 1,100 294 256 199 180 180 178 21 197 182 240 224 250 992 286 250 200 182 175 186 22 187 184 222 218 268 960 286 243 203 185 174 192 23 190 183 208 220 270 798 304 240 203 184 173 183 24 191 181 212 224 317 704 289 238 201 177 178 182 25 187 178 207 219 381 709 272 235 200 180 180 189 26 192 180 203 232 348 600 280 232 199 178 181 188 27 195 187 203 255 327 407 276 232 189 177 178 188 28 195 193 205 269 312 322 291 239 194 176 174 187 29 184 193 204 252 319 304 303 232 193 176 179 189 30 190 213 198 242 --- 292 299 224 192 177 177 191 31 188 --- 195 250 --- 300 --- 227 --- 189 182 --- Total 5,827 5,470 6,399 8,464 7,456 22,260 8,776 8,105 6,162 5,742 5,487 5,612 Mean 188 182 206 273 257 718 293 261 205 185 177 187 Max 303 213 293 842 381 1,490 315 291 229 197 184 195 Min 160 167 183 193 225 292 272 224 189 176 170 178 Ac-ft 11,560 10,850 12,690 16,790 14,790 44,150 17,410 16,080 12,220 11,390 10,880 11,130

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1911 - 1943, BY WATER YEAR (WY) Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Mean 2,206 2,373 2,676 3,000 3,927 4,449 4,446 3,229 2,520 2,214 2,100 2,107 Max 3,021 3,186 6,792 7,675 7,989 9,953 11,410 6,216 3,763 3,218 2,987 2,975 (WY) (1912) (1912) (1938) (1914) (1942) (1938) (1917) (1938) (1911) (1911) (1911) (1911) Min 1,607 1,740 1,764 1,750 1,746 2,051 1,860 1,734 1,672 1,584 1,526 1,565 (WY) (1935) (1934) (1935) (1937) (1933) (1931) (1934) (1934) (1934) (1934) (1934) (1934)

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SUMMARY STATISTICS Water Years 1911 - 1943 Annual mean 2,931 Highest annual mean 4,597 1938 Lowest annual mean 1,787 1934 Highest daily mean 30,300 Dec 12, 1937 Lowest daily mean 692 Jul 9, 1925 Annual seven-day minimum 915 Jul 4, 1925 Maximum peak flow a34,200 Dec 12, 1937 Maximum peak stage 16.26 Dec 12, 1937 Annual runoff (ac-ft) 2,123,000 10 percent exceeds 4,520 50 percent exceeds 2,440 90 percent exceeds 1,750 a From rating extended above 11,000 ft³/s on basis of velocity-area studies.

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1944 - 2008, BY WATER YEAR (WY) Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Mean 200 213 508 1,045 1,174 1,348 1,087 710 278 140 140 131 Max 2,322 2,469 3,889 8,804 9,457 6,658 8,441 5,420 3,052 203 448 284 (WY) (1944) (1944) (1965) (1970) (1986) (1995) (1952) (1995) (1998) (1998) (1992) (1986) Min 58.8 56.0 45.0 51.4 57.1 52.6 49.9 114 78.5 63.5 60.9 60.1 (WY) (1949) (1979) (1979) (1949) (1977) (1977) (1977) (1977) (1944) (1944) (1944) (1945)

SUMMARY STATISTICS Calendar Year 2007 Water Year 2008 Water Years 1944 - 2008 Annual total 80,789 95,760 Annual mean 221 262 578 Highest annual mean 1,698 2006 Lowest annual mean 86.5 1977 Highest daily mean 986 Mar 11 1,490 Mar 16 36,500 Feb 21, 1986 Lowest daily mean 150 Jul 2 160 Oct 8 34 Mar 29, 1955 Annual seven-day minimum 155 Jun 27 169 Oct 3 40 Dec 7, 1978 Maximum peak flow 2,220 Jan 4 49,000 Jan 25, 1970 Maximum peak stage 8.93 Jan 4 18.70 Feb 20, 1986 Annual runoff (ac-ft) 160,200 189,900 419,000 10 percent exceeds 289 306 1,520 50 percent exceeds 189 203 148 90 percent exceeds 167 177 80

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10,000

5,000

2,000

1,000

500

MEAN DISCHARGE, CUBIC FEET PER SECOND MEAN DISCHARGE, CUBIC FEET PER SECOND 200

100 O N D J F M A M J J A S 2007 2008

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