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Water Tracker

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


As of May 1, 2015

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Over the first three months of the year, water use by the major retailers has been reduced by only 5% compared to the same period in 2013. In addition, overall groundwater pumping is above average. As a result of limited recharge due to the drought and increased pumping, groundwater levels in most areas continue to decline. To maximize the use of limited surface water supplies and reduce groundwater pumping, the District is adding imported water to Anderson Reservoir to ensure adequate treatment plant supplies this summer. The City of San Jose and several other agencies have responded to the District Board of Directors request for a countywide water use reduction of 30% relative to 2013 and a restriction on irrigating ornamental landscape with potable water to two days a week according to the following schedule:

  • Odd numbered addresses may water on Mondays and Thursdays;
  • Even numbered addresses may water on Tuesdays and Fridays; and
  • Properties without an address may water on Mondays and Thursdays.

In addition, the State Water Resources Control Board released its framework to achieve mandatory water reductions and the California Energy Commission approved new water appliance standards to save billions of gallons of water per year.




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Rainfall in San Jose:

  • Month of April = 0.87 inches
  • Total to date = 12.60 inches or 91% of average to date (rainfall year is July 1 to June 30)
  • May 4 Northern Sierra snowpack water content is about 2% of normal for this date



Local Reservoirs

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  • Total May 1 storage = 84,966 acre-feet
    (Click here for current local reservoir storage)
    • 72% of 20-year average for that date
    • 50% of total capacity
    • 69% of restricted capacity storage
      (169,009 acre-feet total storage capacity limited by seismic restrictions to 122,924 acre-feet)
  • Approximately 2,700 acre-feet of Imported Water delivered into local reservoirs during April 2015

Imported water 

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  • 2015 State Water Project (SWP) and Central Valley Project (CVP) allocations:
    • 2015 SWP allocation:  20% = 20,000 acre-feet
    • 2015 CVP allocations:  Municipal and Industrial users South-of-Delta will receive enough water to meet health and safety needs or 25% of historic use, whichever is greater, 0% for Irrigation.  A total of 40,300 acre-feet is anticipated to be delivered 
  • Reservoir storage (map) (table), as of May 4, 2015:
    • Shasta Reservoir at 58% of capacity (67% of average for this date)
    • Oroville Reservoir at 50% of capacity (61% of average for this date)
    • San Luis Reservoir at 62% of capacity (70% of average for this date)
  • Daily reservoir storage summary (map) (table), current
  • District Semitropic groundwater bank reserves:  The quantity of water currently stored in Semitropic is estimated to be 222,950 acre-feet as of May 1, 2015.  District is pursuing maximum allowable withdrawals in 2015
  • Board Governance Policy No. EL-7.3 includes keeping the Board informed of imported water management activities on an ongoing basis.  In FY15, 23 imported water management agreements were executed as of May 1; staff is continuing to pursue several potential agreements
  • Hetch Hetchy deliveriesEstimated Hetch Hetchy deliveries to Santa Clara County (click to enlarge graph at right):
    • Month of April  = 4,100 acre-feet
    • 2015 Total = 11,700 acre-feet, or 94% of the five-year average



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Groundwater storage:  Total storage at the end of 2015 is predicted to fall within Stage 4 (Critical) of the Water Shortage Contingency Plan if dry conditions continue and no reduction measures are implemented

Santa Clara Plain

Coyote Valley

Llagas Subbasin

Santa Clara Plain
- The April managed recharge estimate is 1,400 acre-feet.  The year-to-date managed recharge estimate is 4,200 acre-feet, or 26% of the five-year average 

- The April groundwater pumping estimate is 10,500 acre-feet.  The year-to-date groundwater pumping estimate is 31,400 acre-feet, or 149% of the five-year average 

- The groundwater level in the Santa Clara Plain (San Jose) is about 17 feet lower than April last year and about 39 feet lower than the five-year average

Coyote Valley
- The April managed recharge estimate is 600 acre-feet.  The year-to-date managed recharge estimate is 2,200 acre-feet, or 66% of the five-year average

- The April groundwater pumping estimate is 770 acre-feet.  The year-to-date groundwater pumping estimate is 2,500 acre-feet, or 81% of the five-year average 

- The groundwater level in Coyote Valley is about two feet higher than April last year and six feet lower than the five-year average
Llagas Subbasin
- The April managed recharge estimate is 870 acre-feet.  The year-to-date managed recharge estimate is 2,500 acre-feet, or 34% of the five-year average 

- The April groundwater pumping estimate is 3,600 acre-feet.  The year-to-date groundwater pumping estimate is 9,700 acre-feet, or 114% of the five-year average 

- The groundwater level in Llagas Subbasin (San Martin) is about nine feet lower than April last year and 36 feet lower than the five-year average


Treated water 

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  • Treated Water DeliveredBelow average demands of 6,932 acre-feet delivered in April
  • This total is 84% of the five-year average for April
  • Estimated year-to-date = 23,305 acre-feet or 81% 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
  • The Board has called for a 30% reduction and a limit of two days per week for irrigation of ornamental landscape with potable water
  • Achieved a 5% decrease in water use through the first three months of 2015 compared to 2013


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  • Recycled WaterEstimated April 2015 production  =  1,600 acre-feet
  • Estimated year-to-date through April = 5,400 acre-feet or 140% of the five-year average
  • Silicon Valley Advanced Water Purification Center produced an estimated 1,874 million gallons (5,751 acre-feet) 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