Report on Evaluation of Proposed Camp Pendleton

Seawater Desalination Project

Water Planning Committee

APRIL 25, 2013

Cesar Lopez Senior Water Resources Specialist

Presentation Outline

Background Report on latest planning and technical

studies Off-Shore Technical Studies Site Development Evaluations Product Water Conveyance Analyses

Preliminary Cost Estimates

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Proposed Desalination Project

• 50 - 150 mgd seawater RO Project

• Phased implementation

• Unique, large coastal site at top of Aqueduct system

• 2 potential sites approved by the Base for further study

• Unlike Carlsbad, project would require new seawater intake and discharge facilities

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Potential Project Benefits to Camp Pendleton

• RELIABILITY – Drought-proof water supply located on the base

• WATER QUALITY – High quality product water – Potential blending opportunity

• OCEAN OUTFALL – Potential for dual-use outfall for treated wastewater and concentrate

from desalination plant

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Project Background

• Conceptual feasibility study completed

• Board added additional technical and environmental studies to CIP in 2009

• Planning MOU between SDCWA and MCBCP executed in 2010 established framework for cooperation during performance of studies

• Consultant contracts executed in 2011 for: • Technical Studies – Issues and impacts of offshore facilities • Site Development Evaluations – Plant and onshore infrastructure • Product Water Conveyance System Analyses

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Technical Studies Objectives

Intakes: • Determine viability of subsurface intake

• Permitting agencies will require evaluation of alternative intake methods

• Considered to have least impact to marine life

• Locate and configure open ocean intake • Can be designed to minimize marine impacts

Brine Discharge:

• Locate and configure discharge system

• Minimize marine impacts

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Technical Studies - Geologic / Hydrogeologic Investigations

• Conducted Geophysical Survey using seismic reflection

• Drilled exploratory boreholes

• Constructed test well and pump tested offshore aquifer

• Built Groundwater Model

Key Findings: • Large sub-seafloor ancient river channel

• Potential favorable geology to support large subsurface intake system

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Technical Studies - Marine Environment Investigations

• Physical Oceanography – Ocean currents – Wave pressure

• Water Quality Monitoring and Sampling

– Temperature – Salinity – Boron / Bromide – Etc.

• Marine Biology Monitoring and Sampling – Ichthyoplankton (larvae) – Phytoplankton (algae) – Demersal Species (fish) – Infauna Invertebrate (sea-floor habitants)

Key Findings: • Typical marine environment –

nothing unusual • No fatal flaws to siting open

ocean intake and discharge 8

• Ancient river channel provides favorable geology for developing a sub-surface intake

• Open ocean intakes are feasible with low and manageable marine environment impacts

• Potential lower cost

• Oceanographic conditions (i.e. ocean currents, wave action) and marine habitat in project area are favorable for siting a brine discharge diffuser system at approx. 40 ft. depth

• Geotechnical conditions are suitable for soft-ground tunnel construction

Technical Studies – Key Conclusions

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Site Development Evaluations Objectives

• Analyze site access, traffic flow, space availability and security • Determine optimal and reliable treatment processes for project

• For maximum utilization, consider producing “untreated” water

• Determine power requirements, supply source and transmission

• Screened Open Ocean

• Subsurface

Prepare water for desalination process

• Conventional or membrane process

• Desalination Process

• Re-hardening • Disinfection

Residual

• Treated Water System • Untreated Water System

Pre-treatment

Intake System

Reverse Osmosis

Post Treatment

Key Treatment Process Design Elements

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MCTSSA Site Rendering

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SRTTP Site Rendering

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• Both sites are viable for construction and operation

• SRTTP Site offers the best site access

• “Untreated” water production possible • Maximum plant utilization • Eliminates any potential overlap with treatment plant production • Increased cost of “re-treatment” • Cost savings likely due to reduced chemical requirements and potential

elimination of second pass RO

• Phase 1 (50 mgd) project can be supported by existing power supply infrastructure.

• Future phases would require new power supply infrastructure ($91 - $164 million)

Site Evaluations – Key Conclusions

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Product Water Conveyance Analyses

• 19 – 21 miles 72 inch diameter pipeline

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Product Water Conveyance Key Conclusions

• The southern alignment provides the best opportunity for efficient integration into the Water Authority Aqueduct system

• Shorter alignment • Best alignment for both untreated and treated water integration • least direct impact to MCBCP

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Elev

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Length (ft)

Pipeline Reach

HGL of Pipeline 4EL 1242

150 MGD – EL 1300100 MGD – EL 127250 MGD – EL 1254

2A 2B 2C 2D 2E 2F 2G

Proposed Forebay and Pump StationEL 650Proposed Desalination

Facilities and Pump StationEL 60

150 MGD – EL 892100 MGD – EL 767

50 MGD – EL 686

Ground Profile

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Capital Cost Summary

50 mgd Initial Phase

Plant Site

Seawater Intake

Desalination Plant

Brine Discharge

Conveyance System

Total

MCTSSA $218 - $360 $670 - $698 $184 $328 $1,428 - $1,542

SRTTP $241 - $369 $636 - $663 $207 $317 $1,429 - $1,529

Based on supply integration into the untreated system. Costs include oversizing buried project components for the 150 mgd ultimate capacity.

Costs in million $

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Cost Estimate Summary

Plant Production Capacity 50 mgd 150 mgd

Capital Costs (million$) Desalination Plant 1,110 – 1,260 2,320 – 2,900 Conveyance 317 – 328 350 – 360 Annual O&M Costs (million$) 61 - 70 174 - 200

Total Unit Cost ($ per AF) 2,750 - 3,100 2,070 - 2,450

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Questions?

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