Scott Seyfried, PG, CHGGroundwater Ambient Monitoring and Assessment Unit Chief

Division of Water QualityState Water Resources Control Board

Implementing the California Ocean Plan -Desalination Amendments - Analysis of

Subsurface Intake Feasibility

7th Annual Conference, February 6-8Cathedral City , California

Presentation Overview

Brief background on the Ocean Plan and roles of State and Regional Boards

Review of considerations for subsurface intakes (what are we looking for and why?)

Brief overview of the desalination to the Ocean Plan to provide context to the subsurface intake feasibility study

State and Regional Water Boards

Develop Statewide Plans, Policies, and General Orders

Consultation

Develop Water Quality Objectivesand Basin Plan Amendments

Implementation

Issue Permits

Enroll Dischargers in General Orders

Key PointWater Boards staff makes recommendation to the Regional BoardRegional Water Board makes determination by issuing the permit

California Ocean PlanCalifornia’s water quality control plan for ocean waters goals:

• Protect beneficial uses

• Establish water quality objectives

• Implement state law governing areas where ocean discharges are prohibited

• Implemented through NPDES permits issued by the regional water quality control boards

Desalination Amendment, Adopted May 2015 Effective April 2016

Chapter III.M includes the following:1) Applicability and general provisions 2) Direction for the Regional Water Boards for

Water Code §13142.5(b) determinations3) Narrative receiving water limitation for salinity 4) Monitoring and reporting requirements

Desalination Amendment

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“For each new or expanded coastal powerplant or other industrial installation using seawater for cooling, heating, or industrial processing, the best available site, design, technology, and mitigation measures feasible shall be used to minimize the intake and mortality of all forms of marine life.”

Water Code § 13142.5(b) Determinations

Water Code § 13142.5(b) Determinations

Site Design

Technology

Best feasible combination to minimize intake and mortality of

all forms of marine life

Mitigation

“Subject to chapter M.2.a.(2), the regional water board in consultation with State Water Board staff shall require subsurface intakes* unless it determines that subsurface intakes* are not feasible* based upon a comparative analysis of the factors listed below for surface and subsurface intakes.*”

Ocean Plan : Subsurface Intake Considerations

Subsurface intakes required unless not feasible

Slant Wells

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Subsurface Intake Technologies

Vertical Beach Well

Radial Collector Well

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Horizontal Directionally Drilled Wells

Subsurface Intake Technologies

Water Tunnel Intake System Beneath a Beach Area11

Subsurface Intake Technologies

Infiltration Galleries

Sand City California ~ 0.4 Vertical wellsMorrow Bay California ~1.2 Vertical wellsSanta Catalina California ~0.13 Vertical wellsMonterey California (pilot) Slant well (planned expansion to ~ 6 - 9 MGD)Doheny California (pilot) Slant well (possible expansion to ~ 5 -15 MGD)

Source: Water Desalination Report.) September 2014. Vol. 50, No. 33.

Interference with interior aquifers (capture of freshwater resources) Negative impacts to overlying sensitive wetland habits Subsidence of land resulting from excessive drawdown Capture/interference with nearby contaminated groundwater Limited capacity of the aquifer compared with plant demand

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Subsurface Intake Technology – Summary of Potential Challenges (Hydrogeology)

Limited/no access to shoreline Large footprint if many wells are needed Anticipated beach erosion Lack of precedent for use at large intake scales

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Subsurface Intake Technology – Summary of Challenges (Other)

“Subject to chapter M.2.a.(2), the regional water board in consultation with State Water Board staff shall require subsurface intakes* unless it determines that subsurface intakes* are not feasible* based upon a comparative analysis of the factors listed below for surface and subsurface intakes.*”

Ocean Plan : Subsurface Intake Considerations

Subsurface intakes required unless not feasible

Definition of Feasible

CEQA Definition

“‘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)

Feasibility is considered throughout Chapter III.M.2, but some sections include requirements regardless of feasibility

Investigate sites that may support subsurface intakes

“An owner or operator will need to consider a wide range of siting options to ensure that the possibility of using subsurface intakes is not eliminated because the siting options were too narrow.” (from Staff report)

Ocean Plan : Subsurface Intake Considerations

Evaluate combination of surface and subsurface intakes

“If the regional water board determines that subsurface intakes* are not feasible* for the proposed intake design capacity, it shall determine whether subsurface intakes* are feasible* for a reasonable range of alternative intake design capacities.”

Ocean Plan : Subsurface Intake Considerations

“The regional water board shall consider the following factors in determining feasibility of subsurface intakes:

• geotechnical data• hydrogeology• benthic topography• oceanographic conditions• presence of sensitive habitats• presence of sensitive species• Energy use for the entire facility• design constraints (engineering, constructability)• project life cycle cost”

Ocean Plan : Subsurface Intake Considerations

Work with Board staff to determine what level of data is needed for the project, based on results of literature review, and other feasibility criteria.

For groundwater modeling, the lower the level of data intensity, the greater will be the need for wide range of sensitivity analysis.

General Literature Review

Site Specific Literature Review

Lithologic Data (inland)

Lithology and Geophysical Survey (inland)

Lithologic Data (offshore)

Offshore Geophysical Survey

Offshore Geophysical Survey with Lithology

Pumping Test with Observation Well Data

Monitoring Data from Full Scale Operation

Regional

Increasing Data Intensity (and cost)

Increasing Certainty

Level of Data - Hydrogeology

Scott SeyfriedGroundwater Ambient Monitoring and AssessmentDivision of Water Quality(916) 341-5582scott.seyfried@waterboards.ca.gov

Thank You

Extra Slides

Ocean Plan requires subsurface intakes, unless Regional Board determines that subsurface intakes are not feasible

Subsurface intakes act as natural barrier– Eliminate impingement and entrainment– Lower levels of contaminants

Intake Considerations: Subsurface Intakes

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Technical Considerations

Six Types of Intake Designs:

Vertical WellLateral Beach WellHorizontal Collector WellSlant WellInfiltration GalleryHorizontal Directional Drill Well

What is Water Board Staff Looking for in a Subsurface Intake Feasibility Study?

A scientifically based, site specific evaluation that includes:A range of potential sitesA hybrid system

Regional Water Board staff makes recommendation to Regional Water Board (usually concurrent with NPDES permit process)

Proposed Desalination

Facilities

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