s an g abriel v alley w ater f orum s an g abriel v alley w ater s upply presented by: stetson...

SAN GABRIEL VALLEY WATER FORUM

SAN GABRIEL VALLEY WATER SUPPLY

Presented by: Stetson Engineers Inc.

April 17, 2014

SAN GABRIEL VALLEY WATER SUPPLY

• Location of Main San Gabriel Basin • Local water supply conditions • Groundwater level• Rainfall• Historical water use

• Imported water supply conditions• Treated imported water• Untreated imported water

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SAN GABRIEL VALLEY WATER SUPPLY• Stetson Engineers Inc. • Engineer/Consultant to Sponsors of the Water Forum

• Upper San Gabriel Valley Municipal Water District• San Gabriel Valley Municipal Water District• Main San Gabriel Basin Watermaster• Water Quality Authority

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SAN GABRIEL VALLEY WATER SUPPLY

GROUNDWATER BASINS WITHIN LOS ANGELES REGION

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Source: Regional Water Quality Control Board

SAN GABRIEL VALLEY WATER SUPPLY• Local Water Supply Overview• Groundwater levels are approaching a historic low• Third year of below average rainfall• Pre-delivery of untreated imported water; sufficient to satisfy two

future years of Replacement Water requirements• Groundwater levels may not recover in near-term without

significant annual rainfall

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SAN GABRIEL VALLEY WATER SUPPLY• Local water supply management• Groundwater levels

• Based on measurement at “Baldwin Park Key Well”• Basin generally managed between elevation of 200 feet and 250 feet• Measured elevation as of April 11, 2014 about 194 feet• Historical high: 325 feet in 1944• Historical low: 189 feet in 2009

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SAN GABRIEL VALLEY WATER SUPPLY

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SAN GABRIEL VALLEY WATER SUPPLY

RAINFALL AT PASADENA CITY HALL STATION 610B

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SAN GABRIEL VALLEY WATER SUPPLY• Historical water use• Generally ranged between 240,000 acre-feet to 260,000 acre-feet

over past 10 years• Decreased production between 2008 and 2012 as a result of

economy/conservation efforts

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SAN GABRIEL VALLEY WATER SUPPLY

PRODUCTION IN MAIN SAN GABRIEL BASIN

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SAN GABRIEL VALLEY WATER SUPPLY• Imported water supply – State Water Project/Colorado River• Treated water - MWD

• Emphasis on maximizing groundwater production to reduce treated imported water demand

• Treated imported water demand has averaged about 12,000 acre-feet over past four years

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SAN GABRIEL VALLEY WATER SUPPLY• Imported water supply (continued)• Untreated water provided by MWD and SGVMWD (SWP

contractor) • Delivered to San Gabriel Basin as Replacement Water and Cyclic

Storage water (pre-delivery) • Cyclic Storage• Pre-delivery of Replacement Water• Management practice to deliver available imported water supplies to

off-set future Replacement Water demand when imported water supplies may not be available

• Water currently in Cyclic Storage could address about two years of Replacement Water demands

• Water in Cyclic Storage raises measured water level at Baldwin Park Key Well

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SAN GABRIEL VALLEY WATER SUPPLY

BALDWIN PARK KEY WELL GROUNDWATER ELEVATION

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SAN GABRIEL VALLEY WATER SUPPLY• Forecasted water levels at Baldwin Park Key Well• Three forecasted rainfall scenarios (Fiscal years 2014-15 and

2015-16)• Wet/average• Average/average• Dry/average

• No significant increase in water levels unless there is significant annual rainfall

• Long-range forecast suggests 2014-15 may be an “El Niño” year

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SAN GABRIEL VALLEY WATER SUPPLY

FORECAST AT BALDWIN PARK KEY WELL

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SAN GABRIEL VALLEY WATER SUPPLY• Summary• Groundwater levels are approaching a historic low• Third year of below average rainfall• Pre-delivery of untreated imported water; sufficient to satisfy two

future years of Replacement Water requirements• Groundwater levels may not recover in near-term without

significant annual rainfall

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