Monterey Peninsula Water Management District Summary of MPWMD

Monterey Peninsula Water Management District Summary of MPWMD Local Seawater Desalination Project Proposal August 25, 2005 Town Hall Meeting Embassy Suites Hotel; 6: 30 PM Henrietta Stern, MPWMD Project Manager U/hs/ppt/2005/Town. Hall 082505_Desal_HSv 1. ppt 1

Monterey Peninsula Water Management District Boundaries Monterey Bay Pacific Grove Water Management District Sand City Seaside Pebble Beach Monterey Del Rey Oaks Carmel-by-the-Sea Carmel Valley Village Carmel Highlands Carmel River San Clemente Dam Los Padres Dam 2

Monterey Peninsula Water Management District 2002 -03 Board Direction on MPWMD Desal Proposal • Evaluate 8, 400 acre-foot per year (AFY) desalination project in Sand City area, including several intake/disposal options and plant sites. • Sized to comply with SWRCB Order 9510 at existing demand water rights. • Conduct studies to better describe local hydrogeology and effect on project yield. 3

Monterey Peninsula Water Management District Desal Terms: Intake/Disposal • Radial beach well (vertical, with spokes). • Offshore HDD well – horizontal directionally drilled; perpendicular to shoreline; blind hole method. • Onshore HDD well – parallel to shore (along beach); pull-through method. • Brine disposal through MRWPCA regional outfall pipeline. 4

Radial Collector Well 5

Offshore HDD Well (Perpendicular to Shoreline) Blind Hole Method of Construction (Single Entry and Exit Point) 6

Offshore HDD Plan View Ocean Beach 7

Onshore HDD Collector Well (Parallel to Shoreline) Ocean Pull Through Method with Separate Entry and Exit Points + 150’ Beach + 2, 500’ 8

Sand City Desalination Project Overview n EIR Goal of 7. 5 MGD (8, 400 AFA) Treated Water Production. Up to 10 MGD (11, 000 AFA) Production Assessed Former Ford Ord Sand City Plant Sites Seawater Intake Collector Sites Brine Disposal Sites Seaside 9

Monterey Peninsula Water Management District Preliminary Costs – 8, 400 AFY (Ranges in 2002 Dollars) • Total Capital Cost $176 -193 mil (desalination plant, pipelines, disposal, overhead, engineering, environmental, construction markups, legal, land acquisition, contingency). • Annual O&M/Power • Total Annual Cost $8. 8 -9. 0 mil/yr $23 -25 mil/yr (Cap. Cost paid at 7% for 30 years + O&M). • Cost per Acre-Foot $2, 700 -2, 900/AF (Total annual cost divided by 8, 400 AFY). 10

Monterey Peninsula Water Management District Hydrogeologic Studies • Geotechnical (4 test wells) and geophysical (offshore/onshore subsurface soundings) studies conducted to better characterize coastal dune aquifer; affects HDD feasibility and plant yield. • Field work and analysis conducted in Fall 2003 and Winter 2004. • Presentation to Board on March 31, 2004 along with Technical Report. 11

Monterey Peninsula Water Management District Drilling Test Well #1 at Fort Ord 12

Monterey Peninsula Water Management District Geophysical (seismic) testing on the beach 13

Previous Knowledge of Subsurface n Clay Layer Separating Dune Sand aquifer from Paso Robles Drinking Water Aquifer n Uncertainty in Onshore and Offshore Extent of Dune Sand Aquifer – limited coastal data Sand Dune Sea Level Dune Sand Aquifer ? ? ? Clay Layer Paso Robles (Drinking Water) 14

Revised Understanding - Sand City Area n Dune Sand aquifer eroded offshore n Replaced with unconsolidated marine sediments n Suitable for onshore collector n Not suitable for offshore collector Sand Dune Sea Level Marine Sediment Dune Sand Aquifer Silt/Sand Clay Layer Paso Robles (Drinking Water) 15

Revised Understanding - Fort Ord n Clay Layer Absent Beneath Former Fort Ord n Onshore collector options feasible n Brine disposal infeasible due to aquifer connection with lower Paso Robles aquifer Sand Dune Sea Level Dune Sand Aquifer Silt/Sand Marine Sediment Paso Robles (Drinking Water) 16

Engineering Study Summary n Radial wells in Sand City plant production of up to 5, 600 AFA with 4 wells; – Expansion on Fort Ord is needed to get 8, 400 AFA firm capacity or more. n Onshore HDD well at Sand City plant production of 8, 000 AFA; – Expansion on Fort Ord or re-configuration needed to get 8, 400 AFA firm capacity or more. 17

Summary - Continued n Expansion to 10 MGD (11, 000 AFA) would require hybrid Project with combination onshore HDD and radial wells or onshore HDD wells. n Brine discharge is likely limited to single option using outfall at regional wastewater treatment facility. 18

Monterey Peninsula Water Management District Status of EIR and Project • December 15, 2003: “Board Review Draft” EIR received; delay EIR circulation until hydrogeologic reports presented in March 2004; assess feasibility of yields above 8, 400 AFA. • March 31, 2004: Hydrogeologic results and revised yield estimates received; delay EIR circulation until more information on Moss Landing desalination obtained. • June 21, 2004: No funds budgeted to complete and circulate Draft EIR on local desal project; but no formal action taken to terminate EIR. 19

Monterey Peninsula Water Management District Desal Project Status, continued • MPWMD desalination project was tabled in October 2004, based on discussion at Sept. 2004 Strategic Planning Workshop. • Strategic direction is to focus District effort on aquifer storage and recovery (ASR) and opportunities to collaborate on regional water supply projects to meet the Peninsula’s needs. 20

Monterey Peninsula Water Management District For More Information • Website: www. mpwmd. dst. ca. us • Handout in lobby lists specific agenda items to search on website, including staff analyses, report summaries and presentation materials. • Technical reports in MPWMD library. 21