Merkel & Associates, Inc Ruffin Road, San Diego, CA Tel: 858/ Fax: 858/

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1 Merkel & Associates, Inc Ruffin Road, San Diego, CA Tel: 858/ Fax: 858/ Ms. Jessica Woy Waller Department of Boating and Waterways 2000 Evergreen Street #100 Sacramento, CA September 4, 2012 M&A # Re: 6 Month Eelgrass Monitoring Report in Support of the Crown Cove Dock Project (San Diego Bay, California) Dear Ms. Waller, This letter report serves to transmit information regarding the 6 month post transplant eelgrass (Zostera marina) survey completed for the Crown Cove Dock Project in San Diego Bay, California (ACOE #SPL RRS, RWQCB #10C 026, CCC CDP # , POSD # ). INTRODUCTION M&A was retained by the Department of Boating and Waterways to conduct eelgrass monitoring and complete an eelgrass transplant in support of the Crown Cove Dock Project. Work for this project involved the construction of a new recreational dock for the Crown Cove Aquatic Center (Figure 1). The Center is located at 5000 Highway 75, Coronado, CA, along Silver Strand Beach, within the Crown Cove inlet of South San Diego Bay. The new dock is comprised of three components: a concrete sidewalk, a gangway, and a floating platform. The new sidewalk extends from the existing driveway to an 8 ft by 100 ft accessible gangway, which connects to the 20 ft by 30 ft fiberglass floating platform. The platform is held in place with two concrete piles. The dock and gangway cover 228 m 2 of open water. In order to minimize potential eelgrass losses and avoid potential shading impacts on eelgrass, the gangway decking was constructed with an open grating with 33 percent void allowing light passage. The project resulted in the loss of 228 m 2 of open water foraging habitat, which is being mitigated at a 1:1 ratio with eelgrass habitat creation per the Conceptual Eelgrass Mitigation Plan for the Crown Cove Dock Project (RBF, 2011). It was also estimated that up to 312 ft 2 (29m 2 ) of eelgrass may be lost due to shading underneath the new gangway structure. Per the Southern California Eelgrass Mitigation Policy (SCEMP), any loss to eelgrass due to shading would be mitigated at a 1.2:1 ratio, resulting in a potential additional mitigation requirement of up to 35 m 2 of new eelgrass (RBF 2011), for a combined total of up to 263 m 2 of eelgrass creation needed. The final eelgrass mitigation need will be 228 m 2 plus the actual loss of eelgrass occurring as a result of gangway shading as determined by comparison of two annual surveys post construction, with the pre construction eelgrass survey results. MITIGATION AND MONITORING PROGRAM IMPACT STUDY AREA An impact study area was established around the new dock and gangway (Figure 2). While eelgrass impacts are anticipated to be limited to potential shading of the gangway as it crosses over the fringing eelgrass bed, the study area provides a reasonable scale of survey for purposes of establishing a context within which impact assessment may be conducted. All potential impacts of the dock on eelgrass are anticipated to occur within the envelope of the impact study area, although all changes in occur within

2 M&A # CROWN COVE SAN DIEGO BAY Map Area Feet µ Merkel Project Vicinity Map Crown Cove Dock Project & Associates, Inc. Figure 1

3 M&A # SAN DIEGO UNIFIED PORT DISTRICT Mitigation Boundary Expansion STATE PARKS Proposed Dock Eelgrass Mitigation Area Reference Area Eelgrass µ Merkel Pre-construction Eelgrass Survey Crown Cove Dock Project Feet & Associates, Inc. Figure 2

4 Crown Cove 6 Month Eelgrass Monitoring Report September 2012 occur within the envelope of the impact study area, although all changes in eelgrass within the study area are not expected to be related to the project construction. Natural variability in eelgrass bed extent and configuration, as well as non project related recreational use impacts may be noted within the study area as the project is located within a heavily utilized recreational area. As a result of the potential for variability and differing impact factors, long term monitoring will include an assessment of both changes in the eelgrass within the impact study area and changes in eelgrass extent beneath the new gangway. MITIGATION AREA M&A conducted an eelgrass transplant at the site of the Crown Cove Dock Project on March 7 and 15, A total of 397 m 2 of eelgrass was planted within a mitigation area located between existing eelgrass beds adjacent to Crown Cove and the beach at Crown Cove (Figure 2). The restoration area was previously graded to lower the site elevation from being above mean lower low water (MLLW) to approximately 1 foot MLLW. The eelgrass transplant was performed in accordance with transplant methods discussed in the Eelgrass Mitigation Plan (RBF 2011, as modified by Merkel & Associates). At the time of the transplant, the planting units appeared to be healthy and secure in the substrate. Eelgrass was planted within all suitable sediment and bathymetric conditions. The transplant made use of biodegradable soft anchors to fasten bare root units to the bottom. Eelgrass was harvested from the adjacent eelgrass bed (97 units) and a continuation of this bed located offshore of Crown Isle, midway between the Crown Cove and the Loews Coronado Hotel (300 units). During harvest, less than 10% of the bed was harvested. Eelgrass was harvested by hand and processed into planting units of 8 12 leaf shoots per unit. Planting units were processed and planted the same day that harvesting was completed. Harvesting and planting was accomplished by SCUBA divers and on foot during low tides. Planting was conducted on 1 meter centers. REFERENCE AREA An eelgrass reference area has been established in an adjacent area north of the project and mitigation sites in order to monitor natural variability in eelgrass resources to account for any natural changes or fluctuations in the project bed area or density (Figure 2). This reference area was selected based on proximity to, and similarity in, biological characteristics to the impact area and mitigation area. Monitoring of the reference area will be conducted coincident with the monitoring of the restoration area. Changes in the reference area over time will be considered when evaluating the performance of the mitigation area. SURVEY METHODOLOGY The 6 month post transplant survey was conducted on August 28, Data were collected using an interferometric sidescan sonar system, which provided an acoustic backscatter image of the seafloor within the project area. Interpretation of the backscatter data allowed for an assessment of the distribution of eelgrass. Sidescan backscatter data were acquired at a frequency of 468 khz scanning out 35 m on both the starboard and port channels for a 70 m wide swath. The survey was conducted by running parallel transects that were spaced to allow for overlap between adjoining sidescan swaths. Transects were performed until the entirety of the survey area was scanned. All data were collected in latitude and longitude using the North American Datum of 1983 (NAD 83), converted to the Universal Transverse Mercator system in meters (UTM), and plotted on a geo rectified aerial image of the project site. Following completion of the survey, sidescan sonar traces were joined together and geographically registered. Eelgrass was then digitized as a theme to calculate the amount of eelgrass coverage and Merkel &Associates, Inc. #

5 Crown Cove 6 Month Eelgrass Monitoring Report September 2012 show its distribution. This method of eelgrass distribution calculation allows for monitoring eelgrass trends at the project site with a substantial degree of accuracy and repeatability over time. The density of actively growing leaf shoots was determined by conducting shoot counts within 1/16 m 2 quadrats. Replicate quadrats were randomly placed within the eelgrass beds of the mitigation area, impact study area, and reference area to obtain a mean shoot density for eelgrass beds within the three areas. RESULTS IMPACT STUDY AREA The current 6 month survey revealed a total of 93 m 2 of eelgrass within the impact study area (Figures 3 and 5). The eelgrass turion density ( 1 SD) within the impact study area was (n=20) shoots per square meter (Figure 4). The impact study area supported a healthy and robust eelgrass bed with little sediment and epiphytic loading on plant leaves. MITIGATION AREA The current 6 month survey revealed a total of 253 m 2 of eelgrass within the mitigation area (Figures 3 and 5). The eelgrass turion density ( 1 SD) within the mitigation area was (n=20) shoots per square meter (Figure 4). The 6 month survey revealed that the transplanted eelgrass was healthy and expanding. By the completion of the 6 month survey, most of the planting units had coalesced into a continuous bed such that individual planting units could no longer be identified. At the northerly end of the planting area, considerable zoobotryon was observed within the eelgrass beds such that clearing of zoobotryon was required to visually observe much of the eelgrass within approximately one fifth of the transplant site. Eelgrass within the area covered by zoobotryon appears healthy but is sparser than the remainder of the site. REFERENCE AREA The current 6 month survey revealed a total of 182 m 2 of eelgrass within the reference area (Figures 3 and 5). The eelgrass turion density ( 1 SD) within the reference area was (n=20) shoots per square meter (Figure 4). The reference area supported a healthy eelgrass bed with very little sediment and epiphytic loading on plant leaves. Short and dense eelgrass typical of intertidal environments was noted along the highest margin of the reference area, while eelgrass on the slopes was longer and less dense, as expected. DISCUSSION IMPACT STUDY AREA Eelgrass within the impact study area has expanded 39 percent since the time of the March 2011 preconstruction survey (Merkel & Associates 2012c). Based on the pre/post construction surveys, no shading impacts have yet occurred. Given the brief period of time that the gangway has been in place over the eelgrass, the narrow nature of the gangway, the project orientation north south over the eelgrass, and the light passing construction of the gangway, it is highly likely that little if any eelgrass impacts will ultimately arise due to shading impacts. However, the final determination of impacts from shade generating projects is required to be completed following two years of annual post construction monitoring of the impact site pursuant to the SCEMP. For this reason, initial mitigation needs have been based on the bay coverage requirements of 228 m 2 of eelgrass, with the expectation that the mitigation may ultimately rise as any shading effects are identified. Merkel &Associates, Inc. #

6 Feet SAN DIEGO UNIFIED PORT DISTRICT STATE PARKS Dock Area Mitigation Area Reference Area Impact Study Area Eelgrass 6-month Post Transplant Monitoring Report August 2012 Crown Cove Dock Project Figure 3 Merkel & Associates, Inc.

7 M&A# Mitigation Area 350 Impact Study Area Shoot Density (turions/m 2 ) Reference Area 0 0-month 3-month 6-month 12-month 24-month 36-month 48-month 60-month Date Mar-12 Jun-12 Aug-12 Mitigation Area Impact Study Area Reference Area % Mitigation/Reference 4% 38% 85% Transplant Area Eelgrass Shoot Density Relative to Reference Area Shoot Density Crown Cove Dock Project San Diego Bay, CA Figure 4 Merkel & Associates, Inc.

8 M&A# Eelgrass Coverage (m 2 ) Mitigation Area Reference Area Required Ref. Adj. Req Mar-12 0-month Jun-12 3-month Aug-12 6-month 12-month 24-month 36-month 48-month 60-month Eelgrass Coverage at Transplant and Control Sites Relative to Restoration Requirements Crown Cove Dock Project San Diego Bay, CA Figure 5 Merkel & Associates, Inc.

9 Crown Cove 6 Month Eelgrass Monitoring Report September 2012 MITIGATION AREA The mitigation area, originally constructed at 397 m 2, was oversized in order to ensure that adequate eelgrass is established to meet the mitigation needs. At the present time, the mapped beds support 253 m 2 of eelgrass, which is 111 percent of the mitigation need. This margin over the need is considered to be low at this early stage post restoration and considering that no losses of eelgrass due to shading have yet occurred. These facts not withstanding, it is expected that the slope relaxation along the mitigation site margins will allow for additional spread of eelgrass and infill. It is currently believed that the site will meet the success requirements. Eelgrass within the mitigation area initially declined significantly in coverage between the 0 month and 3 month post planting surveys. At the time of the 6 month survey, the site had generally stabilized in eelgrass cover, and it is anticipated that future monitoring results will reveal eelgrass expansion from the present levels. REFERENCE AREA The reference area exhibits characteristics comparable to the impact study area and has similarly shown a 14 percent increase in eelgrass cover from the pre construction period to the 6 month posttransplant/post construction eelgrass survey. MITIGATION SUCCESS CRITERIA Mitigation success evaluation for the present project includes two components. The first is a determination of the actual mitigation area required and the second is a determination as to the performance of the mitigation site relative to the overall mitigation need. Because the project includes an element of potential impact from shading, there is an obligation to assess shading impacts over a two year period following project construction and to mitigate impacts based on losses observed during this period. In addition, the project includes a fixed area mitigation for eelgrass impacts associated with bay coverage (228 m 2 ). The sum of the two mitigation elements constitutes the overall mitigation obligation. Because no shading impacts have yet occurred, the overall mitigation requirement may be subject to increase over the next two years from the present requirement of 228 m 2 (Figure 5). Shading impacts will be assessed through the 24 month monitoring event, at which time the final mitigation requirement for the project will be determined. The mitigation requirement may also be subject to adjustment based on performance of the reference area. This reference adjusted requirement corrects for normal variability in eelgrass distribution due to non project related conditions. For the mitigation area, this eelgrass monitoring program includes milestone success monitoring to verify that minimum coverage and density requirements are achieved within the mitigation area per the requirements of SCEMP. The coverage and leaf shoot density of eelgrass within the restoration and reference areas will be mapped and measured at each monitoring interval. Mitigation will be deemed successful when it has met the success criteria outlined in the SCEMP. Criteria for determination of transplant success will be based upon a comparison of vegetation coverage (area) and density (leaf shoots per square meter) between the reference area and the mitigation area. Extent of vegetation cover is defined as the area where eelgrass is present and where gaps in coverage are less than one meter between individual leaf shoot clusters. Density of shoots is identified as the number of leaf shoots per square meter, as measured from representative areas within the control or transplanted beds. Key success criteria are as follows: A) A minimum of 70 percent areal coverage and 30 percent density should be achieved after the first year. B) A minimum of 85 percent areal coverage and 70 percent density should be achieved after the second year. C) A minimum of 100 percent areal coverage and 85 percent density should be achieved for the third, fourth, and fifth years. Merkel &Associates, Inc. #

10 Crown Cove 6 Month Eelgrass Monitoring Report September 2012 Areas that do not meet the above success criteria will be revegetated and again monitored for another five year period, until the final goal is achieved. This document constitutes the 6 month post transplant monitoring report. There are no success criteria established for 6 months post transplant. As such, there are no standards against which performance must be gauged. The present conditions of the site are exceeding the mitigation needs and the turion density expanding with individual planting unit expansion is a successful condition for this point in the post restoration monitoring schedule. The 12 month eelgrass transplant survey is scheduled for April If you have any questions regarding this report, please do not hesitate to contact me at (858) or kmerkel@merkelinc.com. Sincerely, Keith W. Merkel Principal Consultant Merkel &Associates, Inc. #

11 Crown Cove 6 Month Eelgrass Monitoring Report September 2012 REFERENCES Merkel & Associates. 2012a. Post Transplant Eelgrass Report in Support of the Crown Cove Dock Project, San Diego Bay, CA. Prepared for the California Department of Boating and Waterways, March Merkel & Associates. 2012b. 3 Month Eelgrass Monitoring Report in Support of the Crown Cove Dock Project, San Diego Bay, CA. Prepared for the California Department of Boating and Waterways, June Merkel & Associates. 2012c. Post Construction Eelgrass Survey Report In Support of the Crown Cove Dock Project, San Diego Bay, CA. Prepared for the California Department of Boating and Waterways, September National Marine Fisheries Service Southern California Eelgrass Mitigation Policy. (1991, Revision 11). R.S. Hoffman, ed. RBF Consulting Crown Cove Dock Project Conceptual Mitigation for Potential Eelgrass Habitat Losses. Prepared for the California Department of Boating and Waterways, February Merkel &Associates, Inc. #