Executive Update

Hydrologic Conditions in California (05/01/2013)

Snowpack Water Content
Region	Water Content (in inches)	% Avg to Date	% April 1 Avg (2)
Northern Sierra	3.60	18	13
Central Sierra	6.40	26	21
Southern Sierra	2.00	10	8
Statewide	4.30	19	15

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

Forecast of Regional Water Supply Indices (3)
Index	Value	Year Type
8 River Index for April (in 1000 AF)	2,020	n/a
Sacramento Valley Water Year Type Index (40-30-30) @ 50%	5.8	Dry
Sacramento Valley Water Year Type Index (40-30-30) @ 90%	5.4	Critical
San Joaquin Valley Water Year Type Index (60-20-20) @ 50%	1.8	Critical
San Joaquin Valley Water Year Type Index (60-20-20) @ 75%	1.6	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 04/30/2013 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	2,142	2,049	105	2,448	88	---
Shasta Lake	Sacramento	3,788	3,974	95	4,552	83	-764
Lake Oroville	Feather	3,040	2,939	103	3,538	86	-419
New Bullards Bar Res	Yuba	836	760	110	966	87	-60
Folsom Lake	American	682	730	93	977	70	-121
New Melones Res	Stanislaus	1,457	1,482	98	2,420	60	-769
Don Pedro Res	Tuolumne	1,471	1,470	100	2,030	72	-246
Lake McClure	Merced	543	612	89	1,025	53	-307
Millerton Lake	San Joaquin	330	365	91	520	64	-190
Pine Flat Res	Kings	435	610	71	1,000	43	-565
Isabella	Kern	96	224	43	568	17	-265
San Luis Res	(Offstream)	1,110	1,861	60	2,039	54	---

(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 04/30/2013
	Jul 1 to Date 2012 - 2013 (in inches)	% Avg	Jul 1 to Date 2011 - 2012 (in inches)	% Avg	% Avg Jul 1 to Jun 30 2012 - 2013
Eureka	30.71	81	38.04	101	76
Redding	26.02	81	22.75	71	75
Sacramento	14.68	83	12.18	69	79
San Francisco	16.42	72	15.48	68	69
Fresno	5.60	52	8.15	75	49
Bakersfield	3.10	50	4.93	79	48
Los Angeles	6.50	52	7.60	61	51
San Diego	6.24	61	8.01	79	60

Comments

As of April 30, statewide hydrologic conditions were as follows: precipitation, 75 percent of average to date; runoff, 70 percent of average to date; snow water equivalent, 15 percent of average for the date (10 percent of the April 1 average); and reservoir storage, 95 percent of average for the date. Sacramento River Region unimpaired runoff, for Water Year 2013, observed through April 30, 2013 was about 9.5 million acre-feet (MAF), which is about 71 percent of average. For comparison during Water Year 2012, on April 30, 2012, the observed Sacramento River Region unimpaired runoff through that date was about 8.5 MAF, or about 64 percent of average. Similar to January, February, and March, April had significantly below average rainfall, for almost all of California. On April 30, the Northern Sierra 8-Station Precipitation Index Water Year total was 41.1 inches, which is about 90 percent of the seasonal average to date and 82 percent of an average water year (50.0 inches). During April, the total precipitation for the 8-Stations was 1.5 inches, which is about 38 percent of the monthly average. Last year on April 30, the seasonal total for the 8-Stations was 39.6 inches, or about 87 percent of average for the date. The combined total January through April precipitation is the driest in about 90 years of record. On April 30, the San Joaquin 5-Station Precipitation Index Water Year total was 25.1 inches, which is about 68 percent of the seasonal average to date and 62 percent of an average water year (40.8 inches). During April, the total precipitation for the 5-Stations was 1.9 inches, which is about 54 percent of the monthly average. Last year on April 30, the seasonal total for the 5-Stations was 23.8 inches, or about 64 percent of average for the date. The combined total January through April precipitation is the driest in about 90 years of record. The latest National Weather Service Climate Prediction Center (CPC) long-range, 1-month precipitation outlook for May 2013, issued April 30, 2013, suggests no tendency for above or below average rainfall for most of California, except for the northern third of the State where below average rainfall is expected. Updates to the Executive Summary will generally be issued approximately weekly, biweekly, or monthly (depending on conditions) through the wet months of winter and spring. Beginning about June 1, this product is updated monthly through the dry seasons of summer and fall. The next update of this product will be issued about Tuesday, June 11, 2013, unless there are significant hydrologic changes.