Charles Meyer Desalination Plant

Transcription

1 Charles Meyer Desalination Plant Presentation to CalDesal Meeting October 1, 2015

2 Introduction City built & operated a seawater desalination plant in Permitting for permanent facility was completed in 1996 City maintained desalination plant in standby status as a drought supply RWQCB sought to and subsequently amended the City s NPDES in January 2015 to include Porter Cologne Act Section (b) findings 2

3 History of Long-Term Water Supply Plan 3

4 Desalination & the City s Long-Term Water Supply Plan City voters overwhelmingly approved the desalination facility as permanent part of City s water supply in 1991 City Council added desalination to its permanent water supply in 1994 City Council has reconfirmed desalination as part of its permanent water supply in its 2010 General Plan Update & its 2011 update to the Long Term Water Supply Plan 4

5 Current 7-Year Dry Weather Water Supply Projection Assumes Continued Drought with No Significant Inflow to Gibraltar, Cachuma, or Delta Water Shortage

6 The City s schedule is based upon water supply projections & is consistent with the 2011 LTWSP March 2015 Design/Build/Operate Proposals Received June 2015 Award Contract October 2016 Begin Production 6

7 Desalination facilities are updated with modern technology while maintaining consistency with existing permits 7

8 NPDES Permit Amendment to Include Porter Cologne Act (b) Findings 8

9 As part of the City s long-term water supply planning & desalination was maintained as part of the NPDES permit City conducts desal studies including: Alternative Intakes Alternative Plant Capacities Alternative Technologies Alternative Site Locations 1991 RWQCB Issued Order for Desal Plant WDR Order NPDES CA renewed in 1992, 1999 and Desal Plant begins operation March through June 1996 Council directed staff to place Desal Plant in long-term standby mode 2010 City renews NPDES permit for El Estero WWTP and Desal Plant 2011 City adopted GP and LTWSP which included desalination as drought supply 9

10 Alternative intakes were evaluated in the studies leading up to 1990 desalination proposals Source: TM2 - Seawater Desal Project Technical & Cost Considerations, CH2M Hill, November 11,

11 Two separate field studies were conducted to verify hydrologic conditions Charles Meyer Desalination Plant July 1989 Study Area March 1990 Study Areas 11

12 Subsurface intake study findings Beach Wells were found infeasible: Between 100 and 200 wells would be required (3,500 AFY capacity) Infiltration Galleries were found infeasible: Found to be four times more costly than shallow wells Unconventional technology 12

13 Impingement & entrainment effects were previously evaluated by the City Studied in both the 1991 and 1994 EIRs: Evidence in 1991 and 1994 EIRs supports Section (b) findings Coastal Commission findings: No listed species or sensitive habitats affected No Impingement due to low through-screen velocity Operation Consistent with Coastal Act Policies relating to protection of marine organisms 13

14 Voluntary changes to existing intake City voluntarily offered to update screen type Cylindrical wedge wire 1 mm openings < 0.5 fps City voluntarily offered to fund habitat restoration project Intake screens before installation (1991) 14

15 Summary of City s NPDES permit amendment PROPOSED Ocean Plan Amendments would not have determined City s desalination plant (& intake) to be existing without Porter Cologne Act Section (b) findings included in the NPDES permit Central Coast RWQCB amended City s NPDES Permit to include (b) findings based upon prior studies Condition requiring voluntary measures Condition requiring feasibility studies for subsurface intakes & potable reuse FINAL Ocean Plan Amendments eliminated the requirement for (b) findings to be called existing 15

16 Subsurface Intake Study Scope 16

17 Subsurface intake feasibility study scope Structured based upon Huntington Beach ISTAP process Includes Evaluating technical feasibility of alternatives Maximum yield will be determined Evaluating technical, social, environmental & economic advantages/disadvantages for technically feasible alternatives NWRI advisory panel: peer review & facilitate public comment 17

18 Draft Work Plan defines Feasibility Definition in 2012 CEQA Statute & Guidelines Feasible means capable of being accomplished in a successful manner within a reasonable period of time, taking into account economic, environmental, social, & technological factors Ocean Plan Amendments (Adopted May 6, 2015) Identify 13 factors to determine feasibility of subsurface intakes 18

19 Feasibility factors for subsurface intakes 1. Geotechnical data 2. Hydrogeology 3. Benthic topography 8. Impact on freshwater aquifers, local water supply, & existing water users 4. Oceanographic conditions 9. Desalinated water conveyance 5. Presence of sensitive habitats 6. Presence of sensitive species 10.Existing infrastructure 11.Design constraints (engineering constructability) 7. Energy use 12.Project life cycle costs 13.Other site & facility specific factors 19

20 Initial screening criteria Technological factors in CEQA definition referred to as technical feasibility Certain technical feasibility criteria may render an alternative not feasible Initial screening is required Initial screening criteria: Those technical factors that would not allow a full-scale system to be successfully constructed or operated, would result in a high risk of failure or unacceptable performance 20

21 Summary of subsurface intake feasibility study scope Work Plan Development (RWQCB Requirement) Currently a Draft Defines evaluation criteria Defines how study will be conducted Technical Feasibility Assessment Tsunami hazard, sediment transport study Hydrologic modeling, design criteria development Maximum yield determined Establish predicted water quality & treatment needs Project descriptions Initial Screening technical feasibility Feasibility Screening Social, environmental & economic screening 21