2001 California Hydrologic Data Report
11234700 MAMMOTH POOL RESERVOIR NEAR BIG CREEK, CA.
LOCATION - Lat 37°19'40", long 119°19'38", in SE 1/4 SE 1/4 sec.10, T.7 S., R.24 E., Madera County,
Hydrologic Unit 18040006, Sierra National Forest, in gatehouse of power tunnel intake, 0.7 mi northwest
of dam on San Joaquin River, and 9.0 mi northwest of town of Big Creek.
DRAINAGE AREA - 995 mi".
PERIOD OF RECORD - October 1959 to current year.
GAGE - Water-stage recorder. Datum of gage is sea level (levels by Southern California Edison Co.).
REMARKS - Reservoir is formed by an earthfill dam; storage began Oct. 8, 1959. Usable capacity, 119,940
acre-ft, between elevations 3,100.00 ft, invert of power tunnel, and 3,330.00 ft, crest of spillway.
Additional storage of 2,780 acre-ft is not available for release. Water is diverted from basin through
Ward Tunnel (stations 11229500 and 11235500). Water is diverted from Mammoth Pool through tunnel
for power development and returned to river 8.5 mi downstream from dam. Records, including extremes,
represent usable contents at 2400 hours. See schematic diagram of lower San Joaquin River Basin.
COOPERATION - Records were collected by Southern California Edison Co., under general supervision of
the U.S. Geological Survey, in connection with a Federal Energy Regulatory Commission project. Records
not rounded to U.S. Geological Survey standards.
EXTREMES FOR PERIOD OF RECORD - Maximum contents, 128,944 acre-ft, Jan. 2, 1997, elevation, 3,338.00
ft; minimum contents since appreciable storage was attained, 1,134 acre-ft, Sept. 25, 1992, elevation,
3,112.82 ft.
EXTREMES FOR CURRENT YEAR - Maximum contents, 120,228 acre-ft, May 26, elevation, 3,330.26 ft; minimum,
12,510 acre-ft, Apr. 15, elevation, 3,174.79 ft. Capacity table (elevation, in feet, and contents,
in acre-feet) (Based on table provided by Southern California Edison Co., dated Nov. 6, 1959) 3,100
0 3,130 3,114 3,180 14,060 3,260 56,381 3,105 417 3,140 4,605 3,190 17,414 3,280 72,109 3,110 861
3,150 6,402 3,200 21,400 3,300 89,781 3,115 1,355 3,160 8,618 3,220 31,109 3,320 109,336 3,120 1,900
3,170 11,165 3,240 42,787 3,340 131,255
RESERVOIR STORAGE (ACRE-FEET), WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001
DAILY OBSERVATION AT 2400 HOURS
DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
1 26180 20632 20626 16747 17327 19857 34024 39287 119547 103169 87620 45565
2 24793 21038 19589 16903 17569 19861 34432 43684 119023 102600 86328 44530
3 23463 21473 18700 17016 17863 19398 33868 44988 117799 102071 85055 43575
4 22545 21917 18998 17164 18222 19817 32181 45584 116005 101812 84132 42712
5 21720 22365 19247 17251 18786 20015 30414 46915 115082 101941 83400 41797
6 21392 22819 17966 17399 19322 20185 28150 49907 114130 102071 82161 40775
7 21129 23278 17493 17482 19589 19342 25966 54527 113750 102430 80840 39846
8 20859 23704 16991 17659 19712 18594 23948 59919 113718 102430 79562 39804
9 20218 24134 16581 17463 19621 17989 21759 65206 113623 101623 78108 39093
10 19688 24545 15629 17523 19449 17009 19489 70032 113127 100730 76955 37939
11 19752 24938 14547 17787 19442 16273 17814 74977 112654 100166 76260 37154
12 19744 25298 13777 17947 19203 15251 15483 79160 111992 99359 74500 36460
13 19223 25681 13470 18191 19092 14528 14110 81650 111605 98045 72992 35807
14 19136 26090 13844 18447 19116 14299 13211 84593 111041 98017 71667 35168
15 18993 26463 14107 18610 18731 14646 12510 87225 110477 97949 70008 34493
16 18381 26844 14202 18551 18766 15005 13377 91800 110124 97544 68718 34611
17 18027 27207 14394 18497 18700 15536 15126 96412 109408 97111 66823 34740
18 17207 27588 14464 17901 18700 16471 15887 100720 108277 96507 65014 34102
19 15552 27965 14736 17602 18891 17058 16667 103981 107468 95878 63397 33389
20 15901 28345 14707 17178 19132 17997 17538 106531 107121 95467 60979 32450
21 15901 28484 14788 17131 19279 19748 17883 109233 106531 95268 59609 31744
22 15716 27981 14898 17084 19354 20688 17761 112076 105934 95059 58257 31050
23 16242 26279 15159 17009 19346 23921 17301 114828 105742 94357 57030 30707
24 16266 25734 15416 17098 19469 27328 17997 117072 105792 93494 55587 30196
25 16571 24933 15589 17058 19497 30334 20108 118990 105600 92542 54678 29699
26 16906 24495 15639 16920 19597 29826 23386 120228 105358 91584 53500 29196
27 17051 24130 15854 16938 19656 29505 26653 120084 105056 90620 51929 28686
28 17742 23260 16062 16853 19740 29489 29626 119842 104694 90517 50625 28191
29 18696 23057 16303 16772 --- 30568 31559 119580 104272 90461 49242 27685
30 19302 21764 16474 16903 --- 31239 34560 119601 103741 89633 48492 27106
31 20190 --- 16684 17138 --- 32384 --- 119623 --- 88808 47170 ---
MAX 26180 28484 20626 18610 19740 32384 34560 120228 119547 103169 87620 45565
MIN 15552 20632 13470 16747 17327 14299 12510 39287 103741 88808 47170 27106
a 3197.10 3200.84 3187.96 3189.24 3195.99 3222.34 3226.26 3329.71 3314.49 3298.95 3246.79 3212.32
b -5756 +1574 -5080 +454 +2602 +12644 +2176 +85063 -15882 -14933 -41638 -20064
CAL YR 2000 b +2689
WTR YR 2001 b +1160
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