SAN DIEGO COUNTY WATER AUTHORITY NOTICE OF PREPARATION OF A DRAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT REPORT

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1 DATE: September 18, 2015 SAN DIEGO COUNTY WATER AUTHORITY NOTICE OF PREPARATION OF A DRAFT SUPPLEMENTAL ENVIRONMENTAL IMPACT REPORT TO: State Clearinghouse Governor s Office of Planning and Research Post Office Box Tenth Street Sacramento, California AND Agencies, Organizations, and Interested Parties LEAD AGENCY: San Diego County Water Authority 4677 Overland Avenue San Diego, CA SUBJECT: Notice of Preparation for a Supplement to the Precise Development Plan and Desalination Plant Project EIR for the Carlsbad Desalination Plant Intake and Discharge Facility Modifications The San Diego County Water Authority (Water Authority) is the Lead Agency under the California Environmental Quality Act (CEQA) for preparation of a Supplement to the EIR for the Precise Development Plan and Desalination Plant Project to address changes related to intake and discharge facility modifications. We need to know your views as to the scope and content of the environmental information which is germane to your agency s statutory responsibilities in connection with the proposed changes. Your agency may need to use this Supplement to the EIR when considering your permit or other approvals for individual project components. Due to the time limits mandated by State law, your response must be sent at the earliest possible date but no later than 30 days after receipt of this notice. Please send your written responses, including the name for a contact person in your agency to: Laurence J. Purcell, Water Resources Manager San Diego County Water Authority 4677 Overland Avenue San Diego, CA Telephone: (858) Facsimile: (858) E mail: lpurcell@sdcwa.org 1

2 Project Description and Objectives The project is located at Carlsbad Boulevard, Carlsbad, CA 92008, in north coastal San Diego County (Figure 1 Regional Map) in the vicinity of Agua Hedionda Lagoon, Coast Highway 101 (Carlsbad Boulevard), the railroad and the Pacific Ocean (Figure 2 Vicinity Map). Poseidon Water (Poseidon) is the owner/operator of the Carlsbad Desalination Plant (CDP) under contract to the Water Authority to deliver between 48,000 and 56,000 acre feet per year (AFY) of drinking water from the CDP. On May 5, 2014, Cabrillo Power I LLC (Cabrillo) provided notice that the Encina Power Station (EPS), and the associated seawater intake pump, would be decommissioned, resulting in a permanent shutdown of the seawater intake pump that is currently used to circulate cooling water through the EPS, effective June 1, This action will require the CDP to transition to permanent stand alone intake and discharge operation by this date. The intake and discharge facility modifications to enable permanent stand alone operation comprise the Proposed Project for the purposes of a Supplement to the Precise Development Plan and Desalination Plant Project Final Environmental Impact Report (FEIR) certified in June 2006 and amended September 2009, November 2012, September 2013, and July The Proposed Project is designed to comply with the requirements of Ocean Plan and the Water Code section (b) when the EPS permanently shuts down. As shown in Figure 3, under the Proposed Project, seawater would enter the existing intake tunnels from the outer basin of the Agua Hedionda Lagoon into a new Intake/Discharge Structure. Approximately half of the seawater volume drawn through the intake tunnels would be used for CDP feedwater. The remaining seawater drawn from the intake would be circulated to the discharge channel for initial dilution of the concentrated seawater produced by the CDP prior to discharge to the Pacific Ocean. The CDP feedwater would pass through a series of traveling screens equipped with a fish capture and return system. The screens are designed to eliminate impingement mortality and reduce entrainment mortality through the use of 1 millimeter (mm) slot openings, and a through screen velocity of less than 0.5 feet per second. After screening, the existing intake pump station will continue to deliver the feedwater to the CDP for processing through the pre treatment and reverse osmosis membrane desalination system. Approximately half the feedwater volume processed by the CDP will leave the CDP as potable drinking water, and the other half will be concentrated seawater with about twice the original feedwater salinity. Approximately half of the seawater volume drawn into the new Intake/Discharge Structure would be mixed with the CDP concentrated seawater prior discharge to the ocean. This dilution water would pass through a series of travelling screens equipped with a fish return system. The 1.0 mm mesh screens, with a through screen velocity of less than 0.5 feet per second, are designed to eliminate impingement mortality. The dilution water (and any entrained marine life) would be transferred to the discharge channel using fish friendly low impact pumps that have been demonstrated to minimize entrainment mortality. Consistent with existing CDP operation, the concentrated seawater byproduct of the 2

3 desalination process would be returned to the discharge channel and mixed with the dilution water to reduce salinity in the discharge to a level that has been demonstrated to eliminate toxicity in the receiving water. The new Intake/Discharge Structure would house the screens, the fish friendly low impact pumps and the fish return system. It would be constructed southwest of the existing intake pump station and adjacent to the existing intake forebay. This structure and an associated electrical building would occupy approximately 8,000 square feet, at an elevation of approximately 2 and 12 feet above grade, respectively. In addition, since the CDP approvals, the efficiency of reverse osmosis membrane technology has improved. These advances enable the CDP to increase the average daily potable water output from approximately 50 MGD to approximately 60 MGD with minimal improvements to the plant. Improvements would include installing reverse osmosis membranes into existing housing, and an additional skid, piping, pressure exchangers, booster pumps and other related accessories. Potential Environmental Issues to be Considered in the Supplement to the EIR The environmental document for the proposed intake and discharge facility modifications will be a Supplement to the previously certified EIR in accordance with CEQA Guidelines (Section 15163). The Supplement to the EIR will identify the general environmental effects associated with the physical changes contemplated by the Proposed Project. The Supplement to the EIR will evaluate potential environmental effects from construction and operation of the intake and discharge facility modifications on the following resource topics: o Air Quality o Hydrology and Water Quality o Biological Resources o Growth Inducement o Greenhouse Gas Emissions o Land Use and Planning In order to ensure the Supplement to the EIR addresses all appropriate environmental concerns, this NOP is intended to seek all relevant comments pertaining to the scope of analysis that should be considered in the Supplement to the EIR. Public Scoping Period & Meeting The Water Authority will accept written comments on the NOP regarding scoping of the Supplement to the EIR until October 29, A public scoping meeting will be held on October 1, 2015 from 6:00 PM until 8:00 PM in the Faraday Center, 1635 Faraday Ave., Carlsbad, CA The meeting will provide a public forum for information dissemination, discussion of the public s concerns with respect to the environmental issues noted above, and receipt and response to questions on the project, Supplemental EIR, and the overall CEQA process. No decisions will be made during this meeting, and anyone wishing to make formal comments on the Notice of Preparation must do so in writing. This scoping meeting is intended to satisfy the requirements of the Public Resources Code, Section , which requires the Lead Agency to call at least one scoping meeting for the project. 3

4 Attachments: Figure 1: Regional Map Figure 2: Vicinity Map Figure 3: Site Layout 4

5 San Diego County Imperial County 1 San Juan Capistrano Dana Point g San Clemente Orange County San Diego County Temecula Rainbow 371 Riverside County San Diego County Salton Sea 5 Camp Pendleton North Fallbrook Bonsall Camp Pendleton South Oceanside Vista 15 Hidden Meadows Project Site 76 Valley Center 79 Borrego Springs 86 Carlsbad San Marcos Escondido Santa Ysabel P a c i f i c Encinitas 56 Poway 67 Ramona San Diego Country Estates 78 Julian O c e a n 209 Coronado San Diego Lemon Grove La Mesa National City Bonita Santee Lakeside El Cajon Spring Valley Rancho San Diego Jamul Harbison Canyon Alpine 8 Pine Valley Boulevard Miles 75 Imperial Beach Chula Vista Campo MEXICO Jacumba Copyright:' 2014 Esri 8426 Carlsbad Desal SEIR FIGURE 1 Regional Map

6 Project Site 5 0 1,000 2,000 Feet Modified Intake Boundary Copyright:' 2013 National Geographic Society, i-cubed 8426 SOURCE: USGS 7.5-Minute Series - San Luis Ray Quadrangle. Carlsbad Desal SEIR FIGURE 2 Vicinity Map

7 8426 SOURCE: Carlsbad Desal SEIR FIGURE 3 Site Layout