Groundwater Assessment Study for the Metropolitan Water District of Southern California Southern California Water Dialogue May 2008

Service Area Water Supplies Four million AF of total average annual retail demand Local groundwater production supplies 37% of the total average annual retail demand in Metropolitan’s service area

Overview Metropolitan Board requested study in Fall 2005 Collaborative effort with member agencies and groundwater basin managers Technical and factual baseline using existing data Reviews period 1985 through 2004

Report Content Regional overview and groundwater basin reports Physical characteristics of each basin, and management, facilities and operations Regional trends in management, facilities, production, recharge, water levels Assessment of storage space available

Regional Overview Findings On average, over 1.5 million AF produced annually from groundwater basins 0.75 million AF actively recharged each year Recharge utilizes storm runoff, recycled water, and imported water

Regional Overview Findings In 2004/05 capital facility investments include: –More than 4,300 active production wells –36 ASR wells –5,000 acres of spreading basins –7 seawater intrusion barriers –16 desalters –400 acres of water quality wetlands

Adjudicated Un-adjudicated Management Statute / Adopted Plan Groundwater Basin Governance in 2006

Northwest MWD Service Area Basins San Fernando Valley Basins LA County Coastal Plain Basins San Gabriel Valley Basins Orange County Basins Inland Empire Basins Eastside MWD Service Area Basins San Diego County Basins Trends in Production (Acre-Feet) 151,844 89, , , , , ,085 51, , , , , , , ,355 52, ’ ’04

Northwest MWD Service Area Basins San Fernando Valley Basins LA County Coastal Plain Basins San Gabriel Valley Basins Orange County Basins Inland Empire Basins Eastside MWD Service Area Basins San Diego County Basins Trends in Recharge (Acre-Feet) 104,550 64, , , ,672 14,212 24, ,050 74, , , ,556 30,060 24, ’ ’05

Comparison of Production and Recharge Trends Time period Average Annual Production (AF) Average annual recharge (AF) Production supported by recharge ,450,817759,57852% ,564,062741,63347%

Trends in Recharge Mix Average 1985/86 to 1994/95Average 1995/96 to 2004/05 Spreading Runoff 63% Injection Imported 3% Injection Recycled 2% In-lieu10% Spreading Imported 16% Spreading Recycled 6% Spreading Runoff 56% Injection Imported 4% Injection Recycled 1% In-lieu11% Spreading Imported 21% Spreading Recycled 7%

Regional Overview Findings In 2004/05, active recharge utilized 60% of the reported available capacity In 2004/05, 21% of production was reported as treated or blended for water quality purposes 3.2 million AF of basin capacity is available for storage subject to resolution of issues and determinations of institutional, operational and economic feasibility

Northwest MWD Service Area Basins San Fernando Valley Basins LA County Coastal Plain Basins San Gabriel Valley Basins Orange County Basins Inland Empire Basins Eastside MWD Service Area Basins San Diego County Basins Available Basin Storage Space (AF) 945, , , , , , ,000 19,000

Approved Projects 1. N. Las Posas (Phases 1&2) 2. Long Beach 3. Foothill MWD 4. TVMWD / La Verne 5. Chino Basin 6. Orange County Basin 7. Compton 8. Long Beach - Lakewood 9. Upper Claremont Heights – TVMWD 10. Elsinore In-Basin Groundwater Storage Projects Identified Projects 11. Raymond Basin - Pasadena 12. N. Las Posas (Phase 3)

Issues for Storage Need for funding –Water quality treatment –Capital infrastructure Mismatch of storage with overlying demand Resolution of institutional disagreements Regulatory issues Availability of surplus water to store

Groundwater Workshops Objective: Develop recommendations to encourage growth in groundwater storage and conjunctive use Purpose: Provide input to Metropolitan’s IRP Update Participants: Metropolitan member agencies and groundwater basin managers Timing: Spring/Summer 2008