“The Salty Truth” Southern California Water Dialog March 23, 2011 Peer A. Swan

“The Salty Truth” Need long term focus on reducing SALT to protect local water supply, which makes up over half the water supply in the MWD service area Need long term focus on reducing SALT to protect local water supply, which makes up over half the water supply in the MWD service area Currently importing nearly 1,300,000 tons of salt per year into the MWD service area with the largest amount coming from the Colorado River. Currently importing nearly 1,300,000 tons of salt per year into the MWD service area with the largest amount coming from the Colorado River.

“The Salty Truth” 1,200,000 SWP at 250 ppm = 272,000 t/yr 1,200,000 SWP at 250 ppm = 272,000 t/yr 1,150,000 CRA at 650 ppm = 1,017,000 t/yr 1,150,000 CRA at 650 ppm = 1,017,000 t/yr Total 1,289,000 t/yr Total 1,289,000 t/yr ======== ========

“The Salty Truth” Santa Ana Watershed Santa Ana Watershed Imports about 700,000 AF/YR Imports about 700,000 AF/YR Average TDS of about 610 ppm Average TDS of about 610 ppm 580,720 tons of salt per year 580,720 tons of salt per year

“The Salty Truth” Santa Ana Watershed Santa Ana Watershed Orange County Sanitation 140 MGD discharge Orange County Sanitation 140 MGD discharge 156,800 AF / yr at 1100 ppm salt 156,800 AF / yr at 1100 ppm salt 235,000 T/yr to ocean 235,000 T/yr to ocean

“The Salty Truth” Santa Ana Watershed Santa Ana Watershed Imported water salt = 580,720 T/yr Less ocean discharge 235,000 T/yr Net imported salt 345,720 T/yr ====== ======

“The Salty Truth” Santa Ana Watershed Santa Ana Watershed Estimated salt imbalance 524,000 T/yr Estimated salt imbalance 524,000 T/yr Imports less ocean discharge 345,720 T/yr Imports less ocean discharge 345,720 T/yr Other Salt contribution 178,280 T/yr Other Salt contribution 178,280 T/yr ====== ======

“The Salty Truth” Santa Ana Watershed - How to achieve balance Santa Ana Watershed - How to achieve balance Estimated salt imbalance 524,000 T/yr Estimated salt imbalance 524,000 T/yr Lower salt in CRA to 200 ppm T/yr Lower salt in CRA to 200 ppm T/yr Lower recycled water to 200 ppm T/yr Lower recycled water to 200 ppm T/yr Lower SWP to 150 ppm T/yr Lower SWP to 150 ppm T/yr Reduce urban contribution 50 ppm T/yr Reduce urban contribution 50 ppm T/yr Reduce import 100,000 AF 200 ppm T/yr Reduce import 100,000 AF 200 ppm T/yr Remaining imbalance 125,520 T/yr Remaining imbalance 125,520 T/yr ======= =======

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