West Basin Municipal Water District Desalination Demonstration Facility Intake Effects Assessment Report August 13, 2014 Submitted to: Ms. Diane Gatza West Basin Municipal Water District 17140 S. Avalon Blvd., Suite 210 Carson, CA 90746 Prepared by: Environmental 141 Suburban Rd., Suite A2, San Luis Obispo, CA 93401 ESLO2012-020.1 Executive Summary Executive Summary This report presents an assessment of potential impacts to marine life due to water withdrawals associated with the operation of open ocean intakes for a demonstration ocean water desalination facility constructed and operated by the West Basin Municipal Water District (West Basin) and an intake for a full-scale desalination plant being proposed by West Basin. The demonstration facility uses a wedgewire screen module (WWS) as part of the intake. WWS was designed to reduce impacts on marine organisms by reducing the number of organisms that are entrained, or drawn into the intake, and the numbers of organisms that become impinged on the screen surface. The two objectives of these studies were 1) to determine the potential effects on marine organisms due to the operation of the intakes for the demonstration and full-scale facilities, and 2) to determine the efficiency of the WWS at reducing the effects of entrainment and impingement. The study assessing the potential effects on marine organisms was completed as one phase of the project, while additional studies were conducted to evaluate the efficiency of the screening system at reducing impacts. The combined results from all studies provide an overall assessment of the impacts of the demonstration facility, the proposed full-scale facility, and of the potential reductions in impacts due to the use of WWS. The purpose of the small-scale temporary Desalination Demonstration Facility (WBDDF) constructed and operated by West Basin at the SEA Lab in Redondo Beach, California was to conduct research and testing on full-scale desalination equipment, including the WWS intake system designed to reduce impacts on marine organisms. When water is withdrawn from a source water body for industrial or municipal purposes, organisms within the water body where the intake is located may be entrained through pumps or impinged on intake screens. The operation of such intake systems can affect biological populations in the source water through removal of larvae that are entrained in water flows and of larger life stages that may be impinged on the intake screens. The results from the studies of the intake system at the WBDDF could be used in the design of a larger facility being proposed by West Basin. Intake Assessment Study The first objective of the studies at the WBDDF was to conduct an assessment of the potential effects on marine organisms due to the operation of the intakes. This involved collecting monthly plankton samples using towed plankton nets over a 12-month study period to provide a baseline characterization of the potentially entrainable fish larvae, fish eggs, and selected invertebrate larvae at the proposed intake location and in the surrounding source water (Figure ES-1). Sampling for the 12-month baseline characterization study was initiated on March 31, 2011 and completed on March 5, 2012. Over the year-long study there were 47 plankton samples collected and processed from the intake station (SWE) and 69 samples collected from the three source water stations (SW1–3) (Figure ESLO2012-020.1 West Basin Municipal Water District ñ Desalination Intake Study ES-1 Executive Summary ES-1). A total of 831 fish larvae in 44 taxonomic groups (including unidentified and/or damaged larvae) was collected at the SWE. Ten taxa comprised over 80 percent of the total mean concentration of fish larvae with the most abundant being jacksmelt (Atherinopsis californiensis), white croaker (Genyonemus lineatus), unidentified larval/post larval fishes, herrings and anchovies (Clupeiformes), combtooth blennies (Hypsoblennius spp.), roughcheek sculpin (Ruscarius creaseri) and garibaldi (Hypsypops rubicundus). Jacksmelt comprised approximately one fourth of the total number of larval fishes collected at SWE. An estimated total of 78,759 fish eggs (adjusted for subsampling) was collected from the intake station during the study period. Of the specimens that could be identified to a lower category, turbot, sanddab, herring, and sand flounder eggs were the most numerous. Fish larvae were generally collected in greater abundance at night than during the day. Target invertebrate larvae included Cancer crab megalops, market squid paralarvae (recently hatched), and California spiny lobster phyllosomes. There were 462 invertebrate specimens collected from seven taxonomic groupings. Cancer crabs representing at least four species were the most abundant of the target invertebrate larvae collected. Figure ES-1. Location of intake (SWE) and source water stations for plankton sampling. A total of 1,397 fish larvae in 59 taxonomic categories was collected at the source water stations (SW1, SW2, and SW3) during the 12 monthly surveys. Jacksmelt, anchovies, and white croaker were the three most abundant taxa overall. The peak in abundance of larval fish at the source ESLO2012-020.1 West Basin Municipal Water District ñ Desalination Intake Study ES-2 Executive Summary water stations occurred during February 2012 and lowest concentrations occurred in June 2011. A total of 106,022 fish eggs (adjusted for subsampling) was collected from the three source water stations during the study period. The eggs were classified into 18 taxa, however, the majority of specimens (73 percent) were in early developmental stages and remained unidentified due to an absence of definitive identification characteristics. The peak in abundance of fish eggs at the source water stations was in August 2011 with approximately 35,000/1,000 m3 and lowest concentrations occurred in January 2012 (2,600/1,000 m3). A total of 457 target invertebrate larvae was collected at the source water stations during the study period including 359 Cancer crab megalopae from five taxonomic groupings. Cancer crab megalopae comprised 78.5 percent of the target larvae collected. The average estimated concentrations of each taxon per survey were extrapolated over each survey period and then the survey period estimates added to provide an estimate of total annual entrainment. Based on a proposed maximum feedwater pumping rate of 170,722 m3 per day (45.1 mgd) for a full-scale facility, it was estimated that 10.2 million larval fishes would be entrained annually through an unscreened intake system (Table ES-1). The WBDDF project had substantially lower pumping rates (1,309 m3 per day [0.346 mgd] average), and 1,935 m3 per day ([0.511 mgd] design), that entrained an estimated 77,939 and 115,208 fish larvae per year, respectively. The maximum annual entrainment estimate for fish eggs was approximately 834.5 million annually based on the 45.1 mgd flows, and 6.4 million based on the average demonstration plant flows of 0.346 mgd. An estimated 3.9 million target invertebrate larvae would be entrained at the maximum rate for the full-scale facility and 30,184 at the minimum calculated flow rate. Seasonally, the highest overall concentrations of larval fishes at Station SWE occurred in January and February 2012 with smaller peaks in September and October 2011, while the lowest concentrations occurred in March and November 2011 (Figure ES-2). Peak concentrations of fish eggs occurred in August 2011 and February 2012. Detailed modeling of potential impacts using the Empirical Transport Model (ETM) was done for the larvae of four fishes (silversides Family Atherinopsidae, white croaker Genyonemus lineatus, northern anchovy Engraulis mordax, and kelpfishes Gibbonsia spp.) and one group of invertebrates, Cancer crabs. These were selected for analysis because they were collected in relatively high abundance during the studies and also were collected during a majority of the 12 surveys. Other fishes, such as garibaldi, were high in overall abundance (Table ES-1) but were only collected during two of the surveys at the intake station and their occurrence at the source water stations only coincided with one of those surveys. As a result, there was only one estimate of entrainment relative to source water stations that could be calculated for garibaldi. The estimate of proportional entrainment is the primary input variable to the ETM and the data for garibaldi would have provided a single estimate for the modeling. As a result, while the ETM estimate of the potential effects of the intake on garibaldi larvae, or the annual proportion of the source water population of larvae entrained by the intake, could be calculated, the reliability of the estimate would be in question. ESLO2012-020.1 West Basin Municipal Water District ñ Desalination Intake Study ES-3 Executive Summary Table ES-1. Estimated annual entrainment of fish larvae, fish eggs, and target invertebrate larvae through an unscreened intake based on data collected with towed plankton nets at the intake station (SWE) from March 2011 through March 2012 for three intake volumes. Estimated Annual Entrainment 3 3 3 1,309 m 1,935 m 170,722 m Taxon Common Name (0.346 mgd) (0.511 mgd) (45.1 mgd) Fish Larvae 1 Atherinopsidae silversides 18,983 28,061 2,475,663 2 larval/post-larval fish larval fishes 7,508 11,099 979,167 3 Genyonemus lineatus white croaker 7,251 10,718 945,568 4 Hypsypops rubicundus garibaldi 5,371 7,939 700,450 5 Clupeiformes herrings and anchovies 5,156 7,622 672,421 6 Hypsoblennius spp. combtooth blennies 5,114 7,560 666,944 7 Engraulidae anchovies 4,548 6,723 593,133 8 Ruscarius creaseri roughcheek sculpin 4,545 6,718 592,713 9 Gibbonsia spp. kelpfishes 2,580 3,814 336,495 10 Citharichthys spp. sanddabs 2,468 3,649 321,907 11 Paralichthys californicus California halibut 1,391 2,056 181,368 12 Pleuronichthys spp.