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Water Tracker

A monthly assessment of trends in water supply
and use for Santa Clara County, California

 

As of November 1, 2014

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Even though the County received some rain in November, we are still below normal for rainfall at the San Jose gauge. As the watershed is so dry from the drought, the rain did not produce any appreciable inflow to our reservoirs. At the beginning of October, the combined storage in our reservoirs was 66% of the 20-year average. Without pumping imported water into our reservoirs this year, the combined storage would be about half or around one-third of the 20-year average. Cumulative 2014 water savings by customers from February to September is estimated at 12%, which is less than the 20% target called by the Board in February. As we are using our groundwater reserves to make it though the drought, it will take time to replenish them. To get groundwater levels back to normal, water use reductions will need to continue in 2015 even if we experience average winter rains. To augment our reduced imported water allocations, the District was able to get some water from our Semitropic groundwater bank in Kern County over the past month. The District is preparing to bring in more water from the Semitropic groundwater bank through the end of this year and next year. 

 

 
 


Weather

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Rainfall in Santa Clara County:

  • Month of October = 0.56 inches
  • Total to date = 0.91 inches or 83% of average to date
  • The average daily high temperature for October was 78 degrees Fahrenheit.  Temperatures were above normal for the month

      

       
 


Local Reservoirs

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  • Total November 1 storage = 53,409 acre-feet
    (Click here for current local reservoir storage)
    • 66% of 20-year average for this date
    • 32% of total capacity
    • 43% of restricted capacity storage
      (169,009 acre-feet total storage capacity limited by seismic restrictions to 122,924 acre-feet)
  • Lowest storage levels are in Uvas, Guadalupe, and Stevens Creek reservoirs at 3%, 5%, and 6% of their total capacities, respectively.  Levels in Chesbro reservoir are below the District's measuring gauge
  • Approximately 32,200 acre-feet of Imported Water delivered into local reservoirs this year
       
 


Imported water 

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  • 2014 State Water Project (SWP) and Central Valley Project (CVP) allocations:
    • SWP allocation:  5% = 5,000 acre-feet (20% of allocation [1,000 acre-feet] may be delivered in summer, 80% after September 1) 
    • CVP allocations:  50% for Municipal and Industrial uses and Zero% for Irrigation for a total of 65,000 acre-feet  
  • 2013 SWP and CVP carryover supplies to 2014:  31,227 acre-feet
  • Reservoir storage (map) (table), as of November 1, 2014:
    • Shasta Reservoir at 24% of capacity (41% of average for this date)
    • Oroville Reservoir at 27% of capacity (45% of average for this date)
    • San Luis Reservoir at 19% of capacity (36% of average for this date)
  • Daily reservoir storage summary (map) (table), current
  • Semitropic groundwater bank reserves:  262,665 acre-feet at start of year.  Withdrawal of banked reserves may be limited by SWP operational constraints, with the available quantity to be determined; California Aqueduct Reverse Flow Project is available to facilitate withdrawal of banked supplies, if necessary
  •  Hetch Hetchy No imported water management agreements executed in October; continuing to pursue several potential agreements for 2015
  • Estimated Hetch Hetchy deliveries to Santa Clara County (click to enlarge graph at right):
    • Month of October  = 4,100 acre-feet
    • 2014 Total = 39,600 acre-feet, or 92% of the five-year average
    • SFPUC called for 10% reduction, current use is down 18% through September
       
 


Groundwater

 

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Groundwater storage:  Total storage at the end of 2014 is projected to fall within Stage 3 (Severe) of the Water Shortage Contingency Plan.


 

Santa Clara Plain

Coyote Valley

Llagas Subbasin

Santa Clara Plain
- The October managed recharge estimate is 420 acre-feet. The year-to-date managed recharge estimate is 10,300 acre-feet or 21% of the five-year average

- The October groundwater pumping estimate is 11,000 acre-feet. The year-to-date groundwater pumping estimate is 101,900 or 139% of the five-year average

- The groundwater level in Santa Clara Plain (San Jose) is about 33 feet lower than last year and about 42 feet lower than the five-year average

Coyote Valley
- The October managed recharge estimate is 550 acre-feet. The year-to-date managed recharge estimate is 5,900 acre-feet, or 53% of the five-year average

- The October groundwater pumping estimate is 920 acre-feet. The year-to-date groundwater pumping estimate is 8,800 acre-feet, or 86% of the five-year average 

- The groundwater level in Coyote Valley is about ten feet lower than last year and 12 feet lower than the five-year average
Llagas Subbasin
- The October managed recharge estimate is 530 acre-feet. The year-to-date managed recharge estimate is 6,900 acre-feet, or 32% of the five-year average 

- The October groundwater pumping estimate is 3,900 acre-feet. The year-to-date groundwater pumping estimate is 35,300 acre-feet, or 96% of the five-year average 

- The groundwater level in Llagas Subbasin (San Martin) is about 21 feet lower than last year and 32 feet lower than the five-year average

       
 

Treated water 

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  •   Treated Water Delivered  Below average demands of 8,470 acre-feet delivered in October
  • This total is 77% of the five-year average for October
  • Estimated year-to-date = 82,500 acre-feet, which is 78% of the five-year average
       
 

 
Conserved water

 

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  • /uploadedImages/Services/CleanReliableWater/WaterSupplyPlanning/WaterTracker_documents_and_images/1-Final_Docs_and_Images/11.Aug_2013_Total-Water-Use.jpgSaved 59,300 acre-feet in FY14 from long-term program (baseline year is 1992)
  • Long-term program goal is to save nearly 63,000 acre-feet in FY15
  • Based on the District's Water Shortage Contingency Plan, the Board set a 2014 water use reduction target of 20%, in addition to long-term program savings
  • Currently achieving a 12% reduction compared to 2013 (through September 2014)
       
 


Recycled
water

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  •   Recycled WaterEstimated October 2014 production  =  1,838 acre-feet (billed semi-annually)
  • Estimated year-to-date = 19,371 acre-feet or 134% of the five-year average
  • Silicon Valley Advanced Water Purification Center produced 1,267 million gallons of advanced purified recycled water since March 25, 2014.  The purified water is blended with existing tertiary recycled water for South Bay Water Recycling Program's customer