Implementing the California Ocean Plan - Desalination Amendments - Analysis of Subsurface Intake Feasibility

Transcription

1 Implementing the California Ocean Plan - Desalination Amendments - Analysis of Subsurface Intake Feasibility 7 th Annual Conference, February 6-8 Cathedral City, California Scott Seyfried, PG, CHG Groundwater Ambient Monitoring and Assessment Unit Chief Division of Water Quality State Water Resources Control Board

2 Presentation Overview Brief background on the Ocean Plan and roles of State and Regional Boards Brief overview of the desalination to the Ocean Plan to provide context to the subsurface intake feasibility study Review of considerations for subsurface intakes (what are we looking for and why?)

3 State and Regional Water Boards Develop Statewide Plans, Policies, and General Orders Consultation Implementation Issue Permits Enroll Dischargers in General Orders Develop Water Quality Objectives and Basin Plan Amendments Key Point Water Boards staff makes recommendation to the Regional Board Regional Water Board makes determination by issuing the permit

4 California Ocean Plan California 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

5 Desalination Amendment Chapter III.M includes the following: 1) Applicability and general provisions 2) Direction for the Regional Water Boards for Water Code (b) determinations 3) Narrative receiving water limitation for salinity 4) Monitoring and reporting requirements 6

6 Water Code (b) Determinations 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.

7 Water Code (b) Determinations Site Design Best feasible combination to minimize intake and mortality of all forms of marine life Technology Mitigation

8 Ocean Plan : Subsurface Intake Considerations Subsurface intakes required unless not feasible 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.*

9 Subsurface Intake Technologies Vertical Beach Well Slant Wells 9

10 Subsurface Intake Technologies Radial Collector Well Horizontal Directionally Drilled Wells 10

11 Subsurface Intake Technologies Infiltration Galleries Water Tunnel Intake System Beneath a Beach Area 11

12 Sand City California ~ 0.4 Vertical wells Morrow Bay California ~1.2 Vertical wells Santa Catalina California ~0.13 Vertical wells Source: Water Desalination Report.) September Vol. 50, No. 33. Monterey California (pilot) Slant well (planned expansion to ~ 6-9 MGD) Doheny California (pilot) Slant well (possible expansion to ~ 5-15 MGD)

13 Subsurface Intake Technology Summary of Potential Challenges (Hydrogeology) 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 13

14 Subsurface Intake Technology Summary of Challenges (Other) Limited/no access to shoreline Large footprint if many wells are needed Anticipated beach erosion Lack of precedent for use at large intake scales 14

15 Ocean Plan : Subsurface Intake Considerations Subsurface intakes required unless not feasible 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.*

16 CEQA Definition Definition of Feasible 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 ; 30108) Feasibility is considered throughout Chapter III.M.2, but some sections include requirements regardless of feasibility

17 Ocean Plan : Subsurface Intake Considerations 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)

18 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.

19 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

20 Level of Data - Hydrogeology Regional General Literature Review Increasing Data Intensity (and cost) 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 Increasing Certainty 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.

21 Thank You Scott Seyfried Groundwater Ambient Monitoring and Assessment Division of Water Quality (916)

22 Extra Slides

23 Intake Considerations: Subsurface Intakes 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 23

24 Technical Considerations Six Types of Intake Designs: Vertical Well Lateral Beach Well Horizontal Collector Well Slant Well Infiltration Gallery Horizontal Directional Drill Well

25 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 sites A hybrid system Regional Water Board staff makes recommendation to Regional Water Board (usually concurrent with NPDES permit process)

26 Proposed Desalination Facilities 4