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Water Tracker

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

 

As of October 1, 2014

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Drought continues throughout the state and groundwater levels in the County continue to decline. Cumulative 2014 water savings through August are estimated at 11% compared to 2013 usage, which is less than the 20% water use reduction target set by the Board in February. The county is projected to drawdown groundwater storage by 100,000 acre-feet this year resulting in a projected start to 2015 with the groundwater basin at the “Severe” level. As it will take time to replenish the groundwater basin, even with median conditions (50% exceedance probability), the call for water use reduction is expected into 2015. On September 26th, the Governor signed the three bills to create a framework for sustainable, local groundwater management for the first time in California history. The bills establish a definition of sustainable groundwater management and require local agencies to adopt management plans for the state's most important groundwater basins, including the subbasins in Santa Clara County.

 

 
 


Weather

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Rainfall in Santa Clara County:

  • Month of September = 0.35 inches
  • Total to date = 0.35 inches or 112% of average to date
  • The average daily high temperature for September was 78 degrees Fahrenheit.  Temperatures were slightly below normal for the month

      

       
 


Local Reservoirs

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  • Total October 1 storage = 59,508 acre-feet*
    (Click here for current local reservoir storage)
    • 66% of 20-year average for this date
    • 35% of total capacity
    • 48% 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 Chesbro, Uvas, Guadalupe, and Stevens Creek reservoirs at 1%, 4%, 6%, and 8% of their total capacities, respectively

      *Total includes over 54% imported water (none stored in the month of September)

       
 


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 October 1, 2014:
    • Shasta Reservoir at 25% of capacity (42% of average for this date)
    • Oroville Reservoir at 30% of capacity (49% of average for this date)
    • San Luis Reservoir at 23% of capacity (49% 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 initiated to expand exchange potential with the CVP
  •  Hetch Hetchy No imported water management agreements executed in September; continuing to pursue several potential agreements
  • Estimated Hetch Hetchy deliveries to Santa Clara County (click to enlarge graph at right):
    • Month of September  = 5,200 acre-feet
    • 2014 Total = 36,500 acre-feet, or 93% of the five-year average
    • 2014 preliminary reduction = 10% voluntary announced by SFPUC on January 31
       
 


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.  If the 20% water use reduction target set by the Board on February 25 is achieved, 2014 end of year storage is projected to be within range of Stage 2 (Alert).


Santa Clara Plain

Coyote Valley

Llagas Subbasin

Santa Clara Plain
- The September managed recharge estimate is 400 acre-feet. The year-to-date managed recharge estimate is 10,000 acre-feet or 23% of the five-year average

- The September groundwater pumping estimate is 10,000 acre-feet. The year-to-date groundwater pumping estimate is 91,100 or 138% of the five-year average

- The groundwater level in Santa Clara Plain (San Jose) is about 29 feet lower than last year and about 39 feet lower than the five-year average

Coyote Valley
- The September managed recharge estimate is 540 acre-feet. The year-to-date managed recharge estimate is 5,400 acre-feet, or 54% of the five-year average

- The September groundwater pumping estimate is 1,000 acre-feet. The year-to-date groundwater pumping estimate is 7,900 acre-feet, or 85% of the five-year average 

- The groundwater level in Coyote Valley is about nine feet lower than last year and 11 feet lower than the five-year average
Llagas Subbasin
- The September managed recharge estimate is 500 acre-feet. The year-to-date managed recharge estimate is 6,200 acre-feet, or 32% of the five-year average 

- The September groundwater pumping estimate is 4,100 acre-feet. The year-to-date groundwater pumping estimate is 31,500 acre-feet, or 96% of the five-year average 

- The groundwater level in Llagas Subbasin (San Martin) is about 20 feet lower than last year and 30 feet lower than the five-year average

       
 

Treated water 

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  •   Treated Water Delivered  Below average demands of 9,690 acre-feet delivered in September
  • This total is 74% of the five-year average for September
  • Estimated year-to-date = 74,000 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 an 11% reduction compared to 2013 (through August 2014)
       
 


Recycled
water

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  •   Recycled WaterEstimated August 2014 production  =  2,805 acre-feet (billed semi-annually)
  • Estimated year-to-date = 15,513 acre-feet or 138% of the five-year average
  • Silicon Valley Advanced Water Purification Center produced 1,124 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 Recycled Program's customer