S AN G ABRIEL V ALLEY W ATER F ORUM S AN G ABRIEL V ALLEY W ATER S UPPLY Presented by: Stetson Engineers Inc. April 17, 2014

S AN G ABRIEL V ALLEY W ATER S UPPLY 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 2

S AN G ABRIEL V ALLEY W ATER S UPPLY 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 3

S AN G ABRIEL V ALLEY W ATER S UPPLY GROUNDWATER BASINS WITHIN LOS ANGELES REGION 4 Source: Regional Water Quality Control Board

S AN G ABRIEL V ALLEY W ATER S UPPLY 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 5

S AN G ABRIEL V ALLEY W ATER S UPPLY 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

S AN G ABRIEL V ALLEY W ATER S UPPLY 7

S AN G ABRIEL V ALLEY W ATER S UPPLY RAINFALL AT PASADENA CITY HALL STATION 610B 8

S AN G ABRIEL V ALLEY W ATER S UPPLY 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 9

S AN G ABRIEL V ALLEY W ATER S UPPLY PRODUCTION IN MAIN SAN GABRIEL BASIN 10

S AN G ABRIEL V ALLEY W ATER S UPPLY 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 11

S AN G ABRIEL V ALLEY W ATER S UPPLY 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 12

S AN G ABRIEL V ALLEY W ATER S UPPLY BALDWIN PARK KEY WELL GROUNDWATER ELEVATION 13

S AN G ABRIEL V ALLEY W ATER S UPPLY Forecasted water levels at Baldwin Park Key Well Three forecasted rainfall scenarios (Fiscal years and ) Wet/average Average/average Dry/average No significant increase in water levels unless there is significant annual rainfall Long-range forecast suggests may be an “El Niño” year 14

S AN G ABRIEL V ALLEY W ATER S UPPLY FORECAST AT BALDWIN PARK KEY WELL 15

S AN G ABRIEL V ALLEY W ATER S UPPLY 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 16