USGS Water Resources Data - California, Water Year 1994
11399000 LAKE ALMANOR AT PRATTVILLE, CA
LOCATION.--Lat 40`12'46", long 121`09'43", in SW 1/4 NE 1/4 sec.11, T.27 N., R.7 E., Plumas County, Hydrologic
Unit 18020121, Lassen National Forest, at intake tower to Butt Valley Tunnel at Prattville, 4.7 mi northwest
of Lake Almanor Dam, and 5.6 mi northwest of Canyondam.
DRAINAGE AREA.--491 mi2.
PERIOD OF RECORD.--July 1913 to current year. Monthly contents only for some periods, published in WSP 1315-A.
Published as "near Prattville" 1937-60. Prior to October 1964, records published as usable contents.
REVISED RECORDS.--WSP 1931: Drainage area.
GAGE.--Nonrecording gage read once daily. Datum of gage is 10.23 ft below sea level (levels by Pacific Gas &
Electric Co.). Prior to June 1, 1965, nonrecording gage at site 4.7 mi southeast at same datum.
REMARKS.--Lake is formed by earthfill dam; storage began in July 1913; dam raised to gage height 4,455 ft in 1917
and 4,515 ft in 1927. Usable capacity, 1,174,887 acre-ft between gage heights 4,422 ft, invert of outlet, and
4,495.5 ft, maximum storage limit. Dead storage, 8,948 acre-ft. Water is diverted by tunnel and penstock to
Butt Valley Powerplant (station 11400600) and then is used for power development in the North Fork Feather
River. Figures given, including extremes, represent total contents at 2400 hours. See schematic diagram of
North Fork Feather River basin.
COOPERATION.--Records were collected by Pacific Gas & Electric Co., under general supervision of the
U.S. Geological Survey, in connection with a Federal Energy Regulatory Commission project. Contents not
rounded to U.S. Geological Survey standards.
EXTREMES (AT 2400) FOR PERIOD OF RECORD.--Maximum contents, 1,142,960 acre-ft, June 8, 1982, gage height,
4,494.00 ft; minimum, 5,230 acre-ft, Feb. 5, 1918, gage height, 4,416.1 ft.
EXTREMES (AT 2400) FOR CURRENT YEAR.--Maximum contents, 887,894 acre-ft, June 19, gage height, 4,484.17 ft;
minimum, 693,703 acre-ft, Dec. 31, gage height, 4,475.94 ft.
Capacity table (gage height, in feet, and contents, in acre-feet)
(Based on surveys by Pacific Gas & Electric Co. in 1924 and 1926)
4,422 8,948 4,434 49,510 4,460 376,686
4,424 10,067 4,437 74,189 4,470 565,519
4,426 11,260 4,440 101,869 4,480 787,304
4,428 13,480 4,445 156,414 4,490 1,036,269
4,430 21,200 4,450 220,848 4,495.5 1,183,835
4,432 34,173 4,455 294,531
RESERVOIR STORAGE (ACRE-FEET), WATER YEAR OCTOBER 1993 TO SEPTEMBER 1994
DAILY OBSERVATION AT 2400 HOURS
DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
1 844181 787304 731665 695279 731665 764997 809605 844181 879771 881000 848539 806271
2 842247 785180 729830 696181 732583 766165 811274 845391 880262 880262 846844 804843
3 839590 783058 730977 697083 732583 767567 811990 846602 880754 880016 844665 803416
4 837418 780938 728455 699114 733732 770140 812945 847813 881491 879279 841764 803654
5 835249 778586 726851 700243 734881 772483 814138 849509 881983 878788 839349 801990
6 832600 776471 724334 700921 736721 774124 815572 851935 883459 877069 837660 800802
7 830194 774593 723420 702729 739253 776236 816528 855821 884690 875842 836454 799615
8 827791 772483 725021 703634 739714 777881 817245 858496 884937 874126 835490 797717
9 825630 770140 724792 704992 740867 779762 818920 860687 885183 873636 834526 795109
10 823471 767801 722277 705672 742943 781645 819877 862637 884444 872656 832359 793215
11 821553 767333 721364 707031 743635 783529 821314 864588 884444 871432 830915 791795
12 819877 765464 719538 707938 744790 784472 822033 865809 884937 869964 829473 789903
13 818441 762897 718170 709073 745715 785888 823231 866786 885922 868741 827791 788246
14 816528 760333 718170 709526 746177 787540 824430 866786 885676 867274 826590 786596
15 815094 758238 715664 710662 747333 788721 824910 868252 886169 865809 825870 784472
16 818441 755912 713616 711570 749417 790139 826830 868985 886415 864588 824670 783058
17 817006 753358 711570 712479 751966 791558 827550 870208 886662 862881 822512 780938
18 814616 751270 710662 713389 752894 792741 828992 870698 886908 863125 823231 779056
19 812467 748722 710662 714298 754286 793688 829953 871677 887894 863368 820595 777176
20 810321 746177 706351 714981 755912 795346 831637 871921 887401 862393 818680 775767
21 808176 743405 704540 716119 757307 796531 832840 871921 887401 860444 818920 773655
22 805795 742943 703182 717714 758238 797954 834044 873146 887155 859470 817723 771780
23 803654 742020 701599 719310 759401 799140 835249 872901 886662 858496 815811 769906
24 803654 739484 700017 723649 759867 801040 835731 873146 885676 857280 814377 768502
25 802941 737641 698888 724563 760799 801990 837901 873636 886169 856307 812706 765931
26 800327 736031 697308 726165 761964 803178 838866 873391 886908 854849 812467 764063
27 798429 734651 696632 727309 763363 804129 839832 874371 886169 853634 812706 761964
28 796057 732813 696181 728226 764063 804843 841281 875352 885183 852663 812467 760333
29 793215 734881 695730 729142 --- 806033 842489 876578 883706 851207 811274 758470
30 791795 733502 694604 730747 --- 807461 843698 877315 882229 851207 810082 756610
31 789430 --- 693703 730747 --- 808890 --- 878297 --- 850236 807937 ---
MAX 844181 787304 731665 730747 764063 808890 843698 878297 887894 881000 848539 806271
MIN 789430 732813 693703 695279 731665 764997 809605 844181 879771 850236 807937 756610
a 4480.09 4477.69 4475.94 4477.57 4479.01 4480.91 4482.36 4483.78 4483.94 4482.63 4480.87 4478.69
b -57650 -55928 -39799 +37044 +33316 +44827 +34808 +34599 +3932 -31993 -42299 -51327
CAL YR 1993 MAX 1073750 MIN 669320 b +5853
WTR YR 1994 MAX 887894 MIN 693703 b -90470
a Gage height, in feet, at end of month.
b Change in contents, in acre-feet.