Demonstration of Ocean Plan Consistency during … Final - WBMWD... · Zita Yu, PhD, PE Water Resources Engineer CalDesal Conference 2018 February 1, 2018 ... Summary Subsurface intake

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

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Elected Board of Directors

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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

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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

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Imported Supplies:

from 55% to 39%

Recycled

Supplies: from

9% to 14%

Conservation: from

16% to 18%

Ocean Water Desalination Program Step-wise Approach

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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

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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

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• 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

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• 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

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Wells: Fresh Groundwater Interference

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SSI – Infiltration Galleries

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Average annual bed

elevation change

should be <0.5ft

CASE STUDY SANTA MONICA BAY

Wells: Groundwater Conditions and Rights

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Wells: Seawater Barrier Project

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West Coast

Seawater

Barrier

Project

Infiltration Galleries: Sand Transport

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No limestones formation

Dune

Canyon

Mugu

Canyon

Redondo

Canyon

Nourished Beaches

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Ballona Creek

Coastline with

sand nourishment

Coastline without

sand nourishment

Nearshore Geology: Impervious Layer and Cobbles

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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

[email protected]

http://www.westbasindesal.org/

http://www.westbasindesal.org/

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