Water year 2010 saw above average precipitation and snowpack in California due to El Niño conditions, resulting in a 50% allocation from the State Water Project. However, the Colorado River basin continued dry conditions. Local supply conditions in San Diego county improved to average or above average rainfall compared to the very dry 2009 water year. Precipitation and temperatures in October 2010 for the area were also above and below average respectively. La Niña conditions present into winter 2011 are expected to bring above average precipitation to the Pacific Northwest but below average to Southwest California.

1. Water Shortage Management and
Drought Response Plan
Water Planning Committee
October 28, 2010

2. Overview of Water Year 2010
 October 1, 2009 –September 30, 2010
 El Niño conditions brought above average precipitation
and snowpack to the State Water Project
 Final SWP Allocation at 50%
 Dry conditions continued on the Colorado River Basin
 Local supply conditions improved compared to WY
2009 with average to above average rainfall
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3. Summary of Hydrologic Conditions
% of Average
Hydrologic Indicator
WY 2009 WY 2010
Statewide Precipitation 82 109
Statewide Reservoir
79 105
Storage (as of Sep. 30 )
th
Northern Sierra Snowpack
93 143
Maximum Accumulation
Sacramento River
70 86
Unimpaired Runoff
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4. Combined Reservoir Storage
in Oroville and San Luis
6.0 Capacity San Luis Oroville
4.0
0.79 MAF 0.79 MAF 2.55 MAF
2.0 78% average
0.42 MAF
1.76 MAF
54% average 1.76 MAF
1.34 MAF
0.0
September 30, 2009 September 30, 2010
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5. Ongoing Dry Conditions on the Colorado
River Basin in Water Year 2010
• Unregulated inflow to Lake Powell - 70% of normal
• Lake Mead at lowest level on Oct. 17, 2010 since filled
Storage Percent Capacity Storage in MAF*
Lake Powell 63 15.3
Lake Mead 39 10.2
Total System Contents 56 33.3
*As of September 20, 2010
• According to USBR, under certain hydrologic conditions
shortages could be experienced in 2012 Lake Mead
• Arizona and Nevada experience shortages first
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6. Local Weather Conditions
 Precipitation ranged from average to above average
in San Diego County
 Summer temperatures in southern California were
below normal from the coast to the mountains
 Coolest summer in San Diego since 1933
 11th coolest summer on record
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7. Total Local Reservoir Storage
Acre-feet
350,000
300,000
289 TAF
250,000
200,000
150,000
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Average (2001-2010) WY 2009 WY 2010
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9. Local Weather Conditions
 October precipitation was above average and
temperatures below average
Precipitation in San Diego
July 1- October 26 October 1 – 26
Station
Actual Normal Actual Normal
Lindbergh Field 2.08 0.66 2.03 0.33
Ramona Airport 3.35 2.28 3.14 1.60
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10. Water Year 2011 Weather
3-Month Precipitation Outlook
 La Nina conditions November 2010 – January 2011
are present and
expected last through
winter 2011
 Often features above
average precipitation
in Pacific Northwest
and below average in
Southwest
A= Above Average
Source: National Weather Service Climate B= Below Average
Prediction Center October 21, 2010 EC= Equal Chance
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