2009 Water Supply Summary

Liz Cresto

• Water Year Highlights

• Precipitation and Water Use:– Boise – Snake– Bear– Salmon

The 2009 Water Year• Normal snowpack.Normal snowpack.

• Late season snow.Late season snow.

• Rain in June and August.Rain in June and August.

AVERAGE DAILY DISCHARGE - SNAKE RIVER AT LOWER GRANITE DAM

0

50,000

100,000

150,000

200,000

250,000

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

FLOW (CFS)

2006 WATER YEAR

2007 WATER YEAR

2008 WATER YEAR

2009 WATER YEAR

MEAN (1975 - 2008)

2009 April-July Runoff• Snake R. nr Heise* 3978 kaf 120 % of avg 73 rd / 99 years

• Big Wood at Hailey 236 107% 60 / 94

• Boise R. nr Boise* 1226 87 % 45 / 114

• Payette at HSB* 1491 93 % 38/ 90

• Weiser nr Weiser 287 70 % 18 / 67

• Snake at Weiser 5004 90 % 47 / 99

• Salmon at Whitebird 6545 115 % 63 / 97

• St. Joe at Calder 1087 94 % 37 / 91

• Bear at Stewart Dam 165 113 % 30 / 50

* calculated natural flow

Boise River

Rare Precipitation Events in June and August

/wEPDwU/wEPDwU

August Storm on the Boise

• Natural flow increased but operational loss also increased.

• Stewart Decree went from 60% to 75% delivery.

BOISE RIVER RESERVOIR SYSTEM

0

200

400

600

800

1000

1200

1960 1963 1966 1969 1972 1975 1978 1981 1984 1987 1990 1993 1996 1999 2002 2005 2008

1000 ACFT

END OF SEPTEMBER STORAGE

CAPACITY

AVG

Snake

SNAKE RIVER NATURAL FLOW NEAR HEISE

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

1911191519191923192719311935193919431947195119551959196319671971197519791983198719911995199920032007Water Year

Thousands of Acre-Feet

1911-2009

7-Year Moving Average

Red Bars are Moderate El Nino Years

Average

Recharge

• Spring 104,000 Acre-Feet

• Fall anticipate approximately 25,000 Acre-Feet

UPPER SNAKE RIVER RESERVOIR SYSTEM

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

1960196219641966196819701972197419761978198019821984198619881990199219941996199820002002200420062008

1000 ACFT

END OF SEPTEMBER STORAGE

Capacity

Average

Jackson+ Palisades+ Island Park + American Falls

Bear River

BEAR LAKE ADJUSTED STORAGE RELEASE

0

200

400

600

800

1000

1200

1400

1600

6-May13-May20-May27-May3-Jun10-Jun17-Jun24-Jun

1-Jul 8-Jul 15-Jul22-Jul29-Jul5-Aug12-Aug19-Aug26-Aug2-Sep9-Sep16-Sep23-Sep30-Sep

CFS

200420052006200720082009

OUTLET CORRECTED FOR RAINBOW, DINGLE AND DECREE ADJUSTMENT

Last Chance Canal SystemJune Diversions

0

5

10

15

20

25

30

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

1000 Acre-Feet

Last Chance Canal System APR-SEP Diversion

0

20

40

60

80

100

120

1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

1000 ACFT

Stored Water Diversion in Dark Blue ( 2000-2009) Only

BEAR LAKE END OF MONTH STORAGE

0

500

1000

1500

2000

Oct-21Oct-29Oct-37Oct-45Oct-53Oct-61Oct-69Oct-77Oct-85Oct-93Oct-01Oct-09

1000 ACFT

5923.65 FULL

5920

5915

5911

5904

WATER YEARS 1922-2009

ELEVATION

UPSTREAM STORAGE RESTRICTION

Salmon

Chinook Salmon spawning in Iron Creek, tributary to Chinook Salmon spawning in Iron Creek, tributary to Salmon River between Challis and Salmon. Site of IWRB’s Salmon River between Challis and Salmon. Site of IWRB’s

first 20-year agreement not to divert (2007).first 20-year agreement not to divert (2007).

Summary

• Good water supply.

• June Rains eased irrigation demand.

• Decent carryover for next year.

• Think Snow!