October San Diego County Water Supply Conditions

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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