Water-Data Report 2008 11020600 El Capitan Lake near Lakeside, CA River Basin

LOCATION.--Lat 32°5256, long 116°4830 referenced to North American Datum of 1927, in SE ¼ NE ¼ sec.7, T.15 S., R.2 E., San Diego County, CA, Hydrologic Unit 18070304, on left bank, 100 ft upstream from El Capitan Dam on , and 7.0 mi east of Lakeside. DRAINAGE AREA.--188 mi². SURFACE-WATER RECORDS PERIOD OF RECORD.--October 1936 to September 1966 (published with San Diego River at El Capitan Dam, station 11020500), October 1972 to September 1993, March 2004 to current year. Monthend contents only October 1972 to September 1987. October 1936 to September 1945, published in WSP 1315-B, not equivalent due to exclusion of greater part of flow released from Cuyamaca Reservoir. GAGE.--Water-stage recorder. Datum of gage is NGVD of 1929 (levels by city of San Diego). Prior to October 1987, nonrecording gage at same site. REMARKS.--Reservoir is formed by hydraulic fill-rock embankment, completed in 1935. Capacity of reservoir at spillway level, 112,810 acre-ft, elevation, 750.00 ft. Dead storage below lowest outlet, 59 acre-ft, elevation, 574.00 ft. Reservoir storage includes supplemental water. No significant diversion upstream from reservoir. Inflow partly regulated by Cuyamaca Reservoir, capacity, 11,740 acre-ft. Water is released as required for municipal use and irrigation. See schematic diagram of the San Diego River Basin available from the Water Science Center. EXTREMES FOR PERIOD OF RECORD.--Maximum contents observed, 114,500 acre-ft, spilling, Mar. 7, 1980, elevation, 751.09 ft; minimum observed, 2,252 acre-ft, May 1, 1957, elevation, 606.28 ft. EXTREMES FOR CURRENT YEAR.--Maximum contents observed, 58,870 acre-ft, estimated, May 16, elevation, 705.37 ft; minimum observed, 37,380 acre- ft, Nov. 1, elevation, 681.40 ft.

Capacity table (elevation, in feet, and contents, in acre-feet) (Based on table dated May 25, 1956) Elevation Contents Elevation Contents Elevation Contents Elevation Contents 600 1,450 630 7,820 660 20,650 720 71,790 610 2,820 640 11,310 680 33,780 740 97,790 620 4,940 650 15,530 700 50,730 753 117,550

U.S. Department of the Interior U.S. Geological Survey Water-Data Report 2008 11020600 El Capitan Lake near Lakeside, CA—Continued

RESERVOIR STORAGE, ACRE FEET WATER YEAR OCTOBER 2007 TO SEPTEMBER 2008 DAILY OBSERVATION AT 2400 HOURS Day Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

1 37,720 37,430 38,950 40,630 47,270 53,260 57,220 58,620 58,820 56,520 54,940 55,330 2 37,700 37,450 39,010 40,680 47,440 53,430 57,260 58,630 58,780 56,430 54,930 55,350 3 37,700 37,470 39,060 40,710 47,880 53,610 57,310 58,660 58,710 56,350 54,900 55,380 4 37,690 37,500 39,120 40,800 48,680 53,780 57,390 58,700 58,630 56,270 54,880 55,410 5 37,700 37,510 39,160 41,060 49,050 53,960 57,460 58,730 58,590 56,180 54,860 55,440 6 37,690 37,540 39,200 41,290 49,320 54,130 57,520 58,750 58,530 56,090 54,840 55,490 7 37,650 37,590 39,300 42,270 49,560 54,310 57,590 58,770 58,460 56,000 54,820 55,530 8 37,620 37,630 39,390 42,540 49,710 54,470 57,660 58,780 58,390 55,910 54,810 55,570 9 37,620 37,670 39,450 42,720 49,810 54,620 57,730 58,790 58,300 55,820 54,780 55,640 10 37,580 37,720 39,500 42,840 49,880 54,780 57,800 58,800 58,250 55,730 54,760 55,700 11 37,580 37,770 39,550 42,960 49,960 54,940 57,850 58,820 58,170 55,650 54,730 55,770 12 37,560 37,830 39,590 43,070 50,060 55,090 57,920 58,820 58,090 55,570 54,710 55,830 13 37,570 37,870 39,640 43,170 50,150 55,230 57,980 58,840 58,030 55,490 54,710 55,920 14 37,560 37,920 39,700 43,260 50,400 55,370 58,020 58,840 57,950 55,400 54,740 56,000 15 37,540 37,960 39,740 43,360 50,500 55,510 58,070 58,830 57,880 55,320 54,770 56,070 16 37,610 38,000 39,790 43,450 50,570 55,640 58,140 58,840 57,800 55,280 54,810 56,130 17 37,530 38,050 39,840 43,550 50,620 55,740 58,190 58,830 57,730 55,250 54,830 56,200 18 37,540 38,110 39,890 43,630 50,650 55,820 58,220 58,830 57,660 55,230 54,850 56,290 19 37,520 38,140 39,960 43,730 50,660 55,910 58,250 58,800 57,570 55,210 54,880 56,370 20 37,590 38,190 40,020 43,840 50,720 56,010 58,250 58,810 57,480 55,200 54,930 56,440 21 37,510 38,240 40,070 43,930 50,750 56,090 58,260 58,780 57,410 55,180 54,940 56,510 22 37,540 38,290 40,120 44,050 51,230 56,210 58,270 58,780 57,310 55,150 54,980 56,570 23 37,570 38,330 40,180 44,170 51,550 56,330 58,300 58,810 57,220 55,130 55,020 56,670 24 37,470 38,400 40,230 44,300 51,850 56,450 58,360 58,820 57,120 55,100 55,050 56,760 25 37,440 38,440 40,260 44,410 52,220 56,580 58,420 58,830 57,040 55,080 55,080 56,830 26 37,440 38,480 40,320 44,540 52,440 56,720 58,480 58,840 56,950 55,060 55,090 56,920 27 37,430 38,540 40,370 45,530 52,650 56,880 58,510 58,840 56,860 55,050 55,140 57,000 28 37,410 38,590 40,420 46,190 52,860 57,010 58,550 58,830 56,780 55,030 55,180 57,060 29 37,410 38,630 40,460 46,630 53,060 57,090 58,580 58,830 56,700 55,010 55,210 57,140 30 37,400 38,830 40,520 46,910 --- 57,170 58,610 58,830 56,610 54,980 55,270 57,230 31 37,390 --- 40,560 47,100 --- 57,200 --- 58,820 --- 54,960 55,320 --- Max 37,720 38,830 40,560 47,100 53,060 57,200 58,610 58,840 58,820 56,520 55,320 57,230 Min 37,390 37,430 38,950 40,630 47,270 53,260 57,220 58,620 56,610 54,960 54,710 55,330 Elevation, in feet, at end of month 681.41 683.22 685.39 693.03 699.49 703.71 705.11 705.32 703.11 701.45 701.82 703.74 Change in contents, in acre-feet 37,390 38,830 40,560 47,100 53,060 57,200 58,610 58,820 56,610 54,960 55,320 57,230

Calendar Year 2007 Water Year 2008 Max 42,810 58,870 Min 37,380 37,380 Change in Contents, in acre feet -400 +19,500

— 2 — Water-Data Report 2008 11020600 El Capitan Lake near Lakeside, CA—Continued

60,000

55,000

50,000

45,000 OBSERVATION AT 2400 HOURS RESERVOIR STORAGE, ACRE FEET, RESERVOIR STORAGE, ACRE 40,000

35,000 O N D J F M A M J J A S 2007 2008

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