Executive Update

Hydrologic Conditions in California (05/08/2008)

Snowpack Water Content
Region	Water Content (in inches)	% Avg to Date	% April 1 Avg (2)
Northern Sierra	13.20	77	47
Central Sierra	12.20	54	39
Southern Sierra	8.50	46	33
Statewide	11.20	57	39

(2)	April 1 is the date of normal maximum accumulation for the season.

Forecast of Regional Water Supply Indices (3)
Index	Unimpaired Runoff (in 1000 AF)	Year Type
8 River Index for April	1,890	n/a
Sacramento Valley Water Year Type Index (40-30-30) @ 50%	5,400	Critical
Sacramento Valley Water Year Type Index (40-30-30) @ 90%	5,000	Critical
San Joaquin Valley Water Year Type Index (60-20-20) @ 50%	2,200	Dry
San Joaquin Valley Water Year Type Index (60-20-20) @ 75%	2,100	Critical

(3)	For more information see Sacramento & San Joaquin Valley Water Year Type Index forecast: Latest | Previous     (issued monthly from December 1 through May 1)

Key Reservoir Storage As of 05/07/2008 midnight
Reservoir	River	Storage (in 1000 AF)	Avg Storage (in 1000 AF)	% Average	Capacity (in 1000 AF)	% Capacity	Flood Control (4) Encroachment (in 1000 AF)
Trinity Lake	Trinity	1,674	2,079	81	2,448	68	---
Shasta Lake	Sacramento	2,925	3,987	73	4,552	64	-1,627
Lake Oroville	Feather	1,718	2,973	58	3,538	49	-1,810
New Bullards Bar Res	Yuba	712	779	91	966	74	-200
Folsom Lake	American	561	757	74	977	57	-281
New Melones Res	Stanislaus	1,402	1,485	94	2,420	58	-868
Don Pedro Res	Tuolumne	1,382	1,481	93	2,030	68	-400
Lake McClure	Merced	371	629	59	1,025	36	-456
Millerton Lake	San Joaquin	283	374	76	520	54	-162
Pine Flat Res	Kings	442	638	69	1,000	44	-400
Isabella	Kern	203	240	84	568	36	-275
San Luis Res	(Offstream)	1,388	1,829	76	2,039	68	---

(4)	Temporary encroachment into seasonally reserved flood storage space; requirements can vary considerably on a daily basis due to numerous variables: rainfall amounts, anticipated snowmelt, time of year, soil moisture, etc.

Selected Cities Precipitation Accumulation As of 05/07/2008
	Jul 1 to Date 2007 - 2008 (in inches)	% Avg	Jul 1 to Date 2006 - 2007 (in inches)	% Avg	% Avg Jul 1 to Jun 30 2007 - 2008
Eureka	33.91	93	34.90	96	89
Redding	23.65	75	22.73	72	70
Sacramento	13.67	79	10.88	63	76
San Francisco	15.85	80	11.63	59	78
Fresno	8.10	75	6.03	56	72
Bakersfield	2.31	37	3.06	49	35
Los Angeles	13.42	90	3.21	22	88
San Diego	7.02	67	3.85	36	65

Comments

As of May 1, Water Year 2008 statewide hydrologic conditions were as follows: precipitation, 85 percent of average to date; runoff, 55 percent of average to date; and reservoir storage, 85 percent of average for the date. Reservoir storage for May 1 was the lowest since 1994. Snowpack water content on May 1 was about 65% of average for the date and about 50 percent of the April 1 average (April 1 is the normal date of maximum accumulation). Last year on May 1, the snowpack was only about 25 percent of average. Sacramento River unimpaired runoff observed through April 30, 2008 was about 7.2 million acre-feet (MAF), which is about 53% of average. (On April 30, 2007, the observed Sacramento River unimpaired runoff through that date was about 7.8 MAF or about 57% of average.) Statewide water year runoff is forecasted to be about 60 percent of average. The projected median April-July runoff for the water supply basins ranges from 80% (Kaweah River) to 49% (Cosumnes River). The statewide forecast is down, on average, about four percent since the April 22, Bulletin 120 Update forecast. Spring of 2008 is turning out to be extremely dry. The Water Year 2008, Northern Sierra 8-Station Index seasonal total of 33.7 inches is now less than last year's seasonal total of 35.5 inches at this time. The Water Year 2008, 8-Station Index, October through April total of 33.7 inches is the 22nd driest year out of 88 years of record. March 2008, with a precipitation total of 1.6 inches (23% of average) was the sixth driest March of 88 years of record. (Statewide, March precipitation was about 20% of average.) April 2008 was also the sixth driest April on record. For the 8-Stations, the Water Year 2008 combined March and April total precipitation is only 2.3 inches, the driest on record (since 1921). January and early February brought significant amounts of precipitation to California, including heavy snowfall in the mountains. The large water supply reservoirs received some inflow from these storms; however, the amounts were muted because much of the precipitation fell as snow. Because precipitation was significantly below average last year, dry hydrologic conditions still prevail. Storage in most of the major water supply reservoirs is still well below average. The latest National Weather Service Climate Prediction Center (CPC) long-range weather outlook for May 2008, issued April 30, 2008, is forecasting below average precipitation for Northern and Southern California. Average precipitation is forecasted for Central California. Updates to the Executive Summary will generally be issued weekly through the wet months of winter and spring. Beginning about June 1, this product is updated monthly through the dry season during the summer and fall. The next update of this product will be issued about Tuesday, May 20, 2008, unless there are significant hydrologic changes.