Water-Data Report 2008 11231600 Mono Creek below Diversion Dam, near Mono Hot Springs, CA Basin

LOCATION.--Lat 37°2136, long 118°5951 referenced to North American Datum of 1927, Fresno County, CA, Hydrologic Unit 18040006, unsurveyed, in , on left bank, 20 ft downstream from diversion dam, 1.0 mi southwest of Lake Thomas A. Edison, and 2.5 mi northeast of Mono Hot Springs. DRAINAGE AREA.--92.8 mi². SURFACE-WATER RECORDS PERIOD OF RECORD.--October 1986 to current year. Prior to October 1991, published as "at diversion dam." GAGE.--Acoustic-velocity meter on low-flow discharge, and water-stage recorder on diversion reservoir. Elevation of gage is 7,340 ft above NGVD of 1929, from topographic map. Prior to Oct. 1, 1991, at datum 10 ft higher. COOPERATION.--Records collected by Southern Edison Co., under general supervision of the U.S. Geological Survey, in connection with Federal Energy Regulatory Commission project no. 67. REMARKS.--Flow regulated by diversion reservoir and Lake Thomas A. Edison (station 11231000). Most of the flow is diverted at the diversion dam to Mono Creek Conduit (station 11231550), then to Ward Tunnel and (station 11236000) via Portal Powerplant (station 11235500) for further power development in Big Creek powerplants. Discharge, including extremes, represents the combined flow at Mono Creek and spill at diversion dam. See schematic diagram of upper San Joaquin River Basin available from the California Water Science Center. EXTREMES FOR PERIOD OF RECORD.--Maximum daily discharge, 1,350 ft³/s, June 21, 2006; minimum daily, 4.1 ft³/s, Dec. 12-16, 1990.

U.S. Department of the Interior U.S. Geological Survey Water-Data Report 2008 11231600 Mono Creek below Diversion Dam, near Mono Hot Springs, CA—Continued

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

1 8.4 6.5 5.8 6.9 6.9 6.7 6.6 15 15 15 16 487 2 7.1 6.0 5.8 6.9 6.9 6.7 6.7 15 15 14 16 203 3 7.2 6.0 6.9 6.9 6.9 6.7 6.6 15 15 14 16 17 4 7.2 6.0 6.9 6.9 6.9 6.7 6.6 15 15 14 16 18 5 7.2 6.0 6.9 6.9 6.9 6.7 6.7 15 15 16 16 18 6 7.2 6.0 7.1 6.9 6.9 6.7 6.6 15 15 16 16 18 7 7.2 6.0 7.1 6.9 6.9 6.7 6.7 15 15 16 16 18 8 7.2 6.0 7.1 6.9 6.9 6.7 6.7 15 15 16 16 18 9 7.2 5.9 7.1 6.9 6.9 6.7 6.7 15 15 16 16 18 10 7.2 5.9 7.1 6.9 6.9 6.7 6.6 15 15 16 16 18 11 7.2 5.9 7.1 6.9 6.8 6.7 6.7 15 15 16 16 18 12 7.2 5.9 7.1 6.9 6.8 e6.6 6.7 15 15 16 16 18 13 7.2 5.9 7.1 6.9 6.8 e6.7 6.7 15 15 16 16 18 14 7.2 5.9 7.0 6.9 6.8 e6.7 6.7 15 15 16 16 18 15 7.2 5.9 6.9 6.9 6.8 6.7 6.7 15 15 16 16 18 16 7.2 5.9 6.9 6.9 6.8 6.7 6.7 15 15 16 16 18 17 7.2 5.9 6.9 6.9 6.8 6.7 6.7 15 15 16 16 18 18 7.2 5.9 6.9 6.9 6.8 6.7 6.7 15 15 16 16 18 19 7.2 5.9 6.9 6.9 6.8 6.7 6.7 15 15 16 16 18 20 7.7 5.9 6.9 6.9 6.8 6.7 6.7 15 14 16 197 18 21 7.7 5.9 6.9 6.9 6.8 6.7 6.7 15 14 16 525 18 22 7.7 5.9 6.9 6.9 6.7 6.7 6.7 15 14 16 522 18 23 7.4 5.9 6.9 6.9 6.7 6.7 6.7 15 16 16 518 18 24 7.1 5.9 6.9 6.9 6.7 6.7 11 15 17 16 518 18 25 7.0 5.9 6.9 6.9 6.7 6.7 15 15 17 16 516 18 26 7.0 5.9 6.9 6.9 6.7 6.7 15 15 16 16 512 18 27 7.0 5.9 6.9 6.9 6.7 6.7 15 15 15 16 507 18 28 7.0 5.8 6.9 6.9 6.7 6.7 15 15 15 16 500 18 29 7.0 5.8 6.9 6.9 6.7 6.7 15 15 15 16 493 18 30 7.0 5.8 6.9 6.9 --- 6.6 15 15 15 16 493 18 31 7.0 --- 6.9 6.9 --- 6.6 --- 15 --- 16 490 --- Total 224.5 178.0 213.4 213.9 197.4 207.4 254.6 465 453 489 6,095 1,193 Mean 7.24 5.93 6.88 6.90 6.81 6.69 8.49 15.0 15.1 15.8 197 39.8 Max 8.4 6.5 7.1 6.9 6.9 6.7 15 15 17 16 525 487 Min 7.0 5.8 5.8 6.9 6.7 6.6 6.6 15 14 14 16 17 Ac-ft 445 353 423 424 392 411 505 922 899 970 12,090 2,370

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1987 - 2008, BY WATER YEAR (WY) Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Mean 10.1 9.33 9.37 8.51 8.61 8.39 9.83 15.1 56.8 83.4 28.4 15.1 Max 22.9 23.1 27.0 20.9 25.5 17.7 24.7 55.6 524 684 197 39.8 (WY) (2001) (1996) (1996) (1997) (1997) (1997) (2006) (2007) (2006) (1995) (2008) (2008) Min 6.72 5.62 5.69 5.66 5.69 5.42 5.61 9.45 9.98 9.91 9.85 9.67 (WY) (1995) (1992) (1993) (1993) (1993) (2002) (2002) (1994) (1990) (1991) (1994) (1994)

— 2 — Water-Data Report 2008 11231600 Mono Creek below Diversion Dam, near Mono Hot Springs, CA—Continued

SUMMARY STATISTICS Calendar Year 2007 Water Year 2008 Water Years 1987 - 2008 Annual total 4,963.0 10,184.2 Annual mean 13.6 27.8 22.0 Highest annual mean 98.9 2006 Lowest annual mean 7.83 1992 Highest daily mean 145 May 22 525 Aug 21 1,350 Jun 21, 2006 Lowest daily mean 5.8 Nov 28 5.8 Nov 28 4.1 Dec 12, 1990 Annual seven-day minimum 5.8 Nov 26 5.8 Nov 26 4.2 Dec 12, 1990 Annual runoff (ac-ft) 9,840 20,200 15,940 10 percent exceeds 12 18 16 50 percent exceeds 10 7.1 10 90 percent exceeds 6.9 6.6 5.9

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