Water-Data Report 2012 11525400 Trinity Lake near Lewiston, CA Basin

LOCATION.--Lat 40°48′05″, long 122°45′44″ referenced to North American Datum of 1927, in NW ¼ SW ¼ sec.15, T.34 N., R.8 W., Trinity County, CA, Hydrologic Unit 18010211, Trinity National Forest, Whiskeytown-Shasta-Trinity , on side of intake structure of Trinity on Trinity River, and 9 mi north of Lewiston. DRAINAGE AREA.--692 mi².

SURFACE-WATER RECORDS PERIOD OF RECORD.--November 1960 to current year. From October 1963 to September 1997 published as "Clair Engle Lake near Lewiston". GAGE.--Water-stage recorder. Datum of gage is NGVD of 1929 (levels by U.S. Bureau of Reclamation). Prior to Jan. 4, 1962, nonrecording gage at same site and datum. Contents based on capacity table provided by U.S. Bureau of Reclamation, dated April 1962. COOPERATION.--Records were provided by U.S. Bureau of Reclamation, not rounded to U.S. Geological Survey standards. REMARKS.--Lake is formed by an earth-fill dam completed in November 1960. Storage began Nov. 23, 1960. Usable capacity, 2,437,700 acre-ft, between elevations 1,995.5 ft, elevation of invert of river outlets, and 2,370.0 ft, crest of glory hole spillway. Dead storage, 10,000 acre-ft. Operating pool is from elevation 2,145.0 ft, capacity, 312,621 acre-ft, to 2,370.0 ft, capacity, 2,447,700 acre-ft. Figures given represent total contents at 2400 hours. Lake is used for power generation, flood control, and recreation. See schematic diagram of Klamath River and Trinity River Basins available from the Water Science Center. EXTREMES FOR PERIOD OF RECORD.--(at 2400 hours) Maximum contents, 2,588,000 acre-ft, Jan. 19, 1974, elevation, 2,378.32 ft; minimum since first filling, 222,400 acre-ft, Nov. 9, 1977, elevation, 2,120.22 ft. EXTREMES FOR CURRENT YEAR.--(at 2400 hours) Maximum contents, 2,350,327 acre-ft, May 4, elevation, 2,364.01 ft; minimum, 1,799,557 acre-ft, Sept. 30, elevation, 2,326.62 ft.

Capacity table (elevation, in feet, and contents, in acre-feet) (Based on table provided by U.S. Bureau of Reclamation, dated May 8, 1967) Elevation Contents Elevation Contents Elevation Contents 2,100 162,231 2,190 529,611 2,310 1,583,586 2,140 292,859 2,250 955,140 2,380 2,616,989

U.S. Department of the Interior Suggested citation: U.S. Geological Survey, 2013, Water-resources data for the United States, Water U.S. Geological Survey Year 2012: U.S. Geological Survey Water-Data Report WDR-US-2012, site 11525400, accessed at http://wdr.water.usgs.gov/wy2012/pdfs/11525400.2012.pdf Water-Data Report 2012 11525400 Trinity Lake near Lewiston, CA—Continued

RESERVOIR STORAGE, ACRE FEET WATER YEAR OCTOBER 2011 TO SEPTEMBER 2012 DAILY OBSERVATION AT 2400 HOURS Day Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

1 2,161,833 2,063,395 1,971,406 1,935,990 1,958,068 1,958,785 2,100,495 2,342,846 2,323,019 2,205,682 2,075,816 1,927,906 2 2,157,294 2,059,110 1,968,251 1,935,848 1,959,359 1,957,925 2,109,756 2,346,825 2,321,279 2,200,483 2,071,967 1,922,682 3 2,154,419 2,055,135 1,964,809 1,935,706 1,960,506 1,957,210 2,117,235 2,348,894 2,318,906 2,196,049 2,067,976 1,917,882 4 2,151,999 2,051,308 1,961,510 1,935,564 1,961,510 1,956,354 2,123,986 2,350,327 2,317,487 2,191,016 2,064,577 1,913,092 5 2,149,276 2,048,364 1,959,502 1,934,996 1,962,658 1,955,212 2,129,242 2,349,212 2,315,600 2,186,140 2,060,586 1,908,035 6 2,145,958 2,045,126 1,957,638 1,934,428 1,963,662 1,954,642 2,134,049 2,345,711 2,312,297 2,181,569 2,056,460 1,903,119 7 2,142,491 2,041,312 1,956,211 1,934,428 1,965,096 1,953,786 2,138,119 2,342,050 2,308,051 2,177,310 2,052,486 1,898,497 8 2,139,024 2,037,940 1,953,358 1,934,428 1,967,391 1,952,502 2,141,888 2,341,095 2,303,490 2,171,997 2,048,658 1,893,747 9 2,135,556 2,034,568 1,950,647 1,934,003 1,968,968 1,951,075 2,145,657 2,339,981 2,299,890 2,167,594 2,044,978 1,888,717 10 2,134,501 2,031,196 1,948,221 1,933,009 1,969,829 1,950,076 2,152,301 2,339,981 2,295,825 2,162,892 2,039,846 1,884,121 11 2,131,795 2,027,249 1,945,653 1,932,299 1,970,402 1,949,505 2,156,386 2,339,981 2,291,760 2,159,261 2,036,034 1,879,396 12 2,129,092 2,023,891 1,945,082 1,931,590 1,971,550 1,948,792 2,161,681 2,340,777 2,287,070 2,154,722 2,032,515 1,874,671 13 2,125,638 2,020,532 1,943,370 1,930,738 1,971,837 1,950,504 2,168,808 2,342,369 2,283,491 2,150,335 2,028,271 1,870,239 14 2,122,484 2,018,050 1,942,093 1,930,596 1,971,693 1,952,787 2,175,033 2,344,119 2,278,823 2,145,506 2,023,599 1,865,538 15 2,119,030 2,015,277 1,940,815 1,930,029 1,971,406 1,960,937 2,180,655 2,347,780 2,274,778 2,140,682 2,017,904 1,860,838 16 2,116,038 2,012,659 1,939,396 1,929,887 1,971,406 1,975,584 2,186,445 2,349,371 2,271,045 2,135,707 2,013,095 1,855,879 17 2,112,298 2,009,460 1,936,557 1,929,177 1,970,976 1,985,243 2,192,387 2,349,849 2,267,013 2,130,744 2,007,860 1,851,065 18 2,108,559 2,005,970 1,936,274 1,930,312 1,969,972 1,990,741 2,198,954 2,349,053 2,261,741 2,126,389 2,002,334 1,846,389 19 2,105,119 2,003,061 1,936,415 1,932,725 1,969,685 1,994,797 2,206,293 2,347,780 2,256,314 2,122,184 1,996,969 1,842,143 20 2,101,687 2,000,156 1,936,274 1,936,415 1,968,968 1,997,404 2,215,794 2,347,780 2,251,368 2,118,431 1,991,755 1,838,448 21 2,097,962 1,997,838 1,936,132 1,938,686 1,967,964 2,000,011 2,227,926 2,347,939 2,246,887 2,114,991 1,986,252 1,833,932 22 2,094,387 1,996,680 1,935,280 1,941,099 1,967,964 2,002,189 2,243,333 2,346,029 2,242,097 2,111,551 1,981,206 1,829,699 23 2,090,960 1,995,231 1,934,712 1,941,809 1,966,960 2,004,806 2,261,741 2,343,642 2,237,934 2,107,961 1,975,872 1,825,612 24 2,088,133 1,993,203 1,934,428 1,942,660 1,965,670 2,008,296 2,279,290 2,340,618 2,233,777 2,104,670 1,970,689 1,821,660 25 2,083,978 1,990,452 1,933,861 1,944,654 1,964,666 2,011,350 2,295,200 2,337,276 2,229,157 2,100,942 1,965,383 1,817,847 26 2,080,120 1,987,700 1,933,435 1,948,078 1,963,375 2,014,113 2,311,668 2,334,252 2,224,847 2,097,217 1,959,646 1,814,185 27 2,077,449 1,984,666 1,933,009 1,950,789 1,961,080 2,022,138 2,321,753 2,332,037 2,221,011 2,093,642 1,954,642 1,810,386 28 2,075,668 1,981,639 1,932,725 1,952,502 1,960,937 2,031,489 2,328,398 2,329,822 2,216,868 2,089,768 1,949,077 1,806,588 29 2,071,671 1,978,323 1,932,867 1,953,928 1,959,502 2,040,726 2,333,303 2,327,924 2,213,032 2,085,907 1,943,941 1,802,933 30 2,068,568 1,974,863 1,934,854 1,955,070 --- 2,062,508 2,338,231 2,325,867 2,209,198 2,082,345 1,939,112 1,799,557 31 2,065,316 --- 1,935,848 1,956,354 --- 2,086,500 --- 2,324,285 --- 2,078,784 1,933,861 --- Max 2,161,833 2,063,395 1,971,406 1,956,354 1,971,837 2,086,500 2,338,231 2,350,327 2,323,019 2,205,682 2,075,816 1,927,906 Min 2,065,316 1,974,863 1,932,725 1,929,177 1,958,068 1,948,792 2,100,495 2,324,285 2,209,198 2,078,784 1,933,861 1,799,557 Elevation, in feet, at end of month 2,345.40 2,339.20 2,336.47 2,337.91 2,338.13 2,346.83 2,363.25 2,362.37 2,354.96 2,346.31 2,336.33 2,326.62 Change in contents, in acre-feet -101,519 -90,453 -39,015 +20,506 +3,148 +126,998 +251,731 -13,946 -115,087 130,414 -144,923 -134,304

Calendar Year 2011 Water Year 2012 Max 2,426,086 2,350,327 Min 1,708,407 1,799,557 Change in contents, in acre-feet +1,027,278 +241,858

— 2 — Water-Data Report 2012 11525400 Trinity Lake near Lewiston, CA—Continued

2,400,000

2,300,000

, 2,200,000

2,100,000

2,000,000 OBSERVATION AT 2400 HOURS RESERVOIR STORAGE, ACRE FEET ACRE STORAGE, RESERVOIR 1,900,000

1,800,000

1,700,000 O N D J F M A M J J A S 2011 2012

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