Demonstration of Ocean Plan
Consistency during CEQA Review Subsurface Intake Feasibility Analysis
(Case Study)
Zita Yu, PhD, PE Water Resources Engineer
CalDesal Conference 2018 February 1, 2018
www.westbasin.org/desal 1
Outline
• West Basin Municipal Water District
• West Basin’s Ocean Water Desalination Project
• CA Ocean Plan: Intakes
• Subsurface Intake Technology Overview
• Case Study: Santa Monica Bay
• Summary
www.westbasin.org/desal 2
WEST BASIN
MUNICIPAL WATER DISTRICT
3
Elected Board of Directors
www.westbasin.org/desal 4
Division I:
HAROLD C. WILLIAMS
Secretary
Division II:
GLORIA D. GRAY
Treasurer
Division III:
CAROL W. KWAN
Board Member
Division IV:
SCOTT HOUSTON
Vice President
Division V:
DONALD L. DEAR
President
Mission:
Provide a Safe and Reliable
Supply of High Quality Water
to Communities We Serve
Services:
• Imported potable water
• Tailored recycled water
• Conservation
100% Groundwater
(Retailers and Cities)
Pre-1947 Water Supply Portfolio
www.westbasin.org/desal 5
80% Imported Water
(West Basin)
20% Groundwater
(Retailers and Cities)
1990 Water Supply Portfolio
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9% Recycled Water
(West Basin) 55% Imported Water
(West Basin)
19% Groundwater
(Retailers and Cities)
16% Conservation
(West Basin + Retailers)
.4% Brackish Desal
(Retailer)
2015 Water Supply Portfolio
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39% Imported Potable Water
(West Basin)
18% Groundwater
(Retailers)
14% Non-Potable
Recycled Water
(West Basin)
18% Conservation
(West Basin + Retailers)
11% Local Potable
Desalinated Ocean Water
(West Basin)
Potential 2025 Water Supply Portfolio from UWMP
www.westbasin.org/desal 8
Imported Supplies:
from 55% to 39%
Recycled
Supplies: from
9% to 14%
Conservation: from
16% to 18%
Ocean Water Desalination Program Step-wise Approach
www.westbasin.org/desal 9
Pilot Study (2000 – 2008)
Demonstration Facility
(2008-2017)
EIR Preparation
(2015 – Present)
EIR Certification and a Board
Decision
(TBD)
Permitting
(if approved by Board, TBD)
CEQA Review
www.westbasin.org/desal 10
West Basin MWD
• Lead agency
• Project proponent
Review Scope:
• Local Project: 20 MGD
• Initial project
• Reviewed at the project level
• Regional Project: up to 60 MGD
• Potential future expansion
• Reviewed at the project/programmatic level
CA OCEAN PLAN INTAKE REQUIREMENTS
Intake Requirements
www.westbasin.org/desal 12
• A subsurface intake system is preferred.
• If not feasible*, screened intake should be used.
Consideration of “a range of feasible* alternatives for the best site, design, technology, and mitigation measures to minimize intake and mortality of all forms of marine life”.(Water Code § 13145.5(b)
“Feasible means capable of being accomplished in a successful manner within a reasonable period of time, taking into account economic, environmental, social, and technological factors. (Public Resources Code § 21061.1; § 30108)
SUBSURFACE INTAKE TECHNOLOGIES
Subsurface Intake Overview
www.westbasin.org/desal 14
• Types: • Well systems (geological and hydrogeological dependent)
• Infiltration galleries (sediment transport process dependent)
• Benefits: • Eliminate impingement and entrainment of sea life
• Potentially improve intake water quality
• Factors for determining feasibility: • Coastal geological and hydrogeological conditions
• Coastal aquifer and ocean water interaction
• Coastal sediment transport processes
• Onshore site availability
• Absence of ecologically sensitive area
• Constructability
• Technology reliability
• Life cycle costs
Well Systems
www.westbasin.org/desal 15
Wells: Fresh Groundwater Interference
www.westbasin.org/desal 16
SSI – Infiltration Galleries
www.westbasin.org/desal 17
Average annual bed
elevation change
should be <0.5ft
CASE STUDY SANTA MONICA BAY
Wells: Groundwater Conditions and Rights
www.westbasin.org/desal 19
Wells: Seawater Barrier Project
www.westbasin.org/desal 20
West Coast
Seawater
Barrier
Project
Infiltration Galleries: Sand Transport
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No limestones formation
Dune
Canyon
Mugu
Canyon
Redondo
Canyon
Nourished Beaches
www.westbasin.org/desal 22
Ballona Creek
Coastline with
sand nourishment
Coastline without
sand nourishment
Nearshore Geology: Impervious Layer and Cobbles
www.westbasin.org/desal 23
Coastal Site Zoned for Industrial Uses
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Ecologically Sensitive Area
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Subsurface Intake Feasibility Findings
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Wells and infiltration galleries: • Evaluated 9 technologies
• None of them are feasible in Santa Monica Bay
Major constraints: • Nearshore:
• Interference with seawater barrier operations
• Presence of coastal contaminated groundwater plumes
• Groundwater adjudication
• Shallow clay lenses
• Cobbles
• Erosive nearshore seabed with high elevation fluctuations
• Offshore:
• Rough offshore sea conditions
• Unproven technology reliability
• High costs
Summary
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• Subsurface intake (SSI) feasibility analysis is necessary to demonstrate consistency with Ocean Plan requirements during the CEQA process.
• The followings are important factors to consider to evaluate SSI feasibility:
• Coastal sediment transport processes
• Coastal geological and hydrogeological conditions and
interaction
• Ecologically sensitive area
• Onshore site zoning and availability
• Constructability
• Technology reliability
• Life cycle costs
• Others, e.g. water rights
Thank you!
Zita Yu, PhD, PE
http://www.westbasindesal.org/
http://www.westbasindesal.org/
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