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Executive Update
Hydrologic Conditions in California (01/26/2010)
| Northern Sierra Precipitation Accumulation (1) | |
|---|---|
| Rainfall & Snow Water Content (in inches) |
|
| Water Year Amount to Date (since Oct. 1, 2009): | 26.10 |
| Average to Date: | 25.00 |
| Percent of Average to Date: | 104 % |
| Average for the Water Year (Oct. 1 through Sep. 30) | 50.00 |
| Percent of Average for the Water Year (Oct. 1 through Sep. 30) | 52 % |
| (1) | Northern Sierra (Sacramento, Feather, Yuba, and American River Basins) |
| Snowpack Water Content | |||
|---|---|---|---|
| Region |
Water Content (in inches) |
% Avg to Date |
% April 1 Avg (2) |
| Northern Sierra | 20.50 | 123 | 71 |
| Central Sierra | 17.40 | 102 | 58 |
| Southern Sierra | 17.30 | 126 | 66 |
| Statewide | 18.30 | 115 | 64 |
| (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 December (in 1000 AF) | 690 | n/a |
| Sacramento Valley Water Year Type Index (40-30-30) @ 50% | 6.1 | Dry |
| Sacramento Valley Water Year Type Index (40-30-30) @ 90% | 4.4 | Critical |
| San Joaquin Valley Water Year Type Index (60-20-20) @ 50% | 2.9 | Above Normal |
| San Joaquin Valley Water Year Type Index (60-20-20) @ 75% | 2.3 | Dry |
| (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 01/25/2010 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 | 1,022 | 1,743 | 59 | 2,448 | 42 | --- |
| Shasta Lake | Sacramento | 2,453 | 3,084 | 80 | 4,552 | 54 | -1,081 |
| Lake Oroville | Feather | 1,144 | 2,350 | 49 | 3,538 | 32 | -1,702 |
| New Bullards Bar Res | Yuba | 572 | 572 | 100 | 966 | 59 | -224 |
| Folsom Lake | American | 298 | 508 | 59 | 977 | 30 | -279 |
| New Melones Res | Stanislaus | 1,210 | 1,382 | 88 | 2,420 | 50 | -760 |
| Don Pedro Res | Tuolumne | 1,476 | 1,373 | 108 | 2,030 | 73 | -214 |
| Lake McClure | Merced | 442 | 491 | 90 | 1,025 | 43 | -233 |
| Millerton Lake | San Joaquin | 235 | 330 | 71 | 520 | 45 | -178 |
| Pine Flat Res | Kings | 402 | 466 | 86 | 1,000 | 40 | -272 |
| Isabella | Kern | 121 | 166 | 73 | 568 | 21 | -49 |
| San Luis Res | (Offstream) | 1,081 | 1,583 | 68 | 2,039 | 53 | --- |
| (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 01/25/2010 | |||||
|---|---|---|---|---|---|
| Jul 1 to Date 2009 - 2010 (in inches) |
% Avg |
Jul 1 to Date 2008 - 2009 (in inches) |
% Avg |
% Avg Jul 1 to Jun 30 2009 - 2010 |
|
| Eureka | 20.13 | 96 | 13.69 | 66 | 53 |
| Redding | 15.88 | 93 | 8.39 | 49 | 47 |
| Sacramento | 12.04 | 131 | 6.14 | 67 | 67 |
| San Francisco | 12.30 | 118 | 5.31 | 51 | 61 |
| Fresno | 6.05 | 118 | 3.72 | 73 | 54 |
| Bakersfield | 3.67 | 128 | 2.06 | 72 | 57 |
| Los Angeles | 7.60 | 124 | 4.52 | 74 | 58 |
| San Diego | 5.70 | 113 | 6.13 | 122 | 53 |
|   |
| Comments |
|---|
| As of December 31, 2009, statewide hydrologic conditions were as follows: precipitation, 85 percent of average to date; runoff, 40 percent of average to date; and reservoir storage, 75 percent of average for the date. Sacramento River unimpaired runoff observed through December 31, 2009 was about 1.5 million acre-feet (MAF), which is about 47 percent of average. For comparison, on December 31, 2008, the observed Sacramento River unimpaired runoff through that date was about 1.4 MAF, or about 44 percent of average. The latter half of January has been extremely wet for California. A series of extremely strong storms brought significant amounts of rain Statewide, along with large snowfall accumulations in the Sierra. Updated statewide hydrologic numbers and water supply forecasts will be available in early February. The latest National Weather Service Climate Prediction Center (CPC) long-range weather outlook for February 2010, issued January 21, 2009, forecasts above average precipitation for almost all of California. Average precipitation is expected for the far northern portion of the State. Updates to the Executive Summary will generally be issued approximately weekly or biweekly (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 Thursday, February 11, 2010, unless there are significant hydrologic changes. |