CALTRANS BATHYMETRIC SURVEY VICINITY OF YERBA BUENA ISLAND AND OAKLAND MOLE ALONG SFOBB SAN FRANCISCO BAY

Transcription

1 FUGRO PELAGOS, INC. CALTRANS BATHYMETRIC SURVEY VICINITY OF YERBA BUENA ISLAND AND OAKLAND MOLE ALONG SFOBB SAN FRANCISCO BAY CALTRANS CONTRACT 59A0053 Survey Period: February 25 th March 1 st, 2013 Report Number: R1 Prepared for: CALTRANS 5900 Folsom Blvd. Sacramento, CA (916) Client Reference: Issued as Final C. Pratt G. Suarez April 25, Issued as Draft A. Tardif G. Suarez March 13, 2013 Rev Description Prepared Checked Approved Date

2 SURVEY AREA

3 CONTENTS 1. INTRODUCTION AND SCOPE OF WORK General Units and Conventions Abbreviations 2 2. METHODS AND RESOLUTION LIMITATIONS Survey Control Multibeam Bathymetry Positioning and Navigation Offsets Calibration Quality Control / Quality Assurance TPU (Total Propagated Uncertainties) Multibeam Report Processing 14 APPENDICES Page A B C D RESOURCES TECHNICAL SPECIFICATIONS OF SURVEY EQUIPMENT DIGITAL FILES CHARTS Page i

4 TABLES Page Table 2-1. Performance Test Results 11 FIGURES Figure 2-1. Control benchmark (Mole). 3 Figure 2-2. R2 Sonic 2024 mounted on the vessel, Julie Ann. 4 Figure 2-3. R8 base station with survey vessel in the background. 5 Figure 2-4. Roll Bias = 0⁰ 6 Figure 2-5. Roll Bias Computation = -1.65⁰ 6 Figure 2-6. Latency Bias = 0⁰ 7 Figure 2-7. Latency Bias Computation = 0⁰ (no adjustment needed). 7 Figure 2-8. Pitch Bias = 0⁰ 7 Figure 2-9. Pitch Bias Computation = -0.50⁰ 8 Figure Yaw Bias = 0⁰ 8 Figure Yaw Bias Computation = 3.00⁰ 9 Figure Beam Angle Details: Statistical results of performance test with +/- 70 degrees. 10 Figure Beam Angle Curve: Plot of statistical bias and confidence results at various beam angle widths. 10 Figure Angle Test Report: Statistical bias and confidence results at various beam angle widths. 11 Figure Example of a Sound Velocity Cast (02/27/2013) 12 Figure Debris Field 14 Page ii

5 1. INTRODUCTION AND SCOPE OF WORK 1.1 General In support of Caltrans Contract 59A0053, Fugro conducted a hydrographic survey of the East span of the San Francisco Oakland Bay Bridge between Yerba Buena Island and Oakland as a component of the predemolition phase. From February 26 to 28, 2013, Fugro conducted a hydrographic (bathymetric) survey of the East Span of SFOBB. Multibeam echosounder (MBES) sonar bathymetry data were collected 300 feet (91.4 meters) on each side of the bridge centerline except where the two bridges merge together. Due to the nature of the survey, no predetermined tracklines were used for the multibeam survey. No data were collected north of where all three bridge structures merge together due to the inability to collect reliable data safely under the bridges. All coordinates are based on the California Coordinate System, NAD-83 (North American Datum of 1983), Zone 3, in US Survey feet. All bathymetry data collected was reduced to the National Geodetic Vertical Datum of 1929 in feet utilizing Real Time Kinematic (RTK) measurements, based on horizontal/vertical monument Mole recovered near the survey site prior to commencing bathymetric operations. MOLE: North = m (CCS-3 m) East = m (CCS-3 m) Elevation = 2.521m (NGVD29 m) As provided by Caltrans Included at the end of this report are Appendices A through D: Appendix A provides a summary of resources. Appendix B includes technical information on the survey equipment. Appendix C lists the digital files included on accompanying CD. Appendix D contains the six charts created for this project. 1.2 Units and Conventions Units used on the survey are as follows: Linear units are US Survey feet. Angular units are degrees ( ). Time was recorded as UTC (Time offset: -8:00 UTC) to all data files. Page1

6 1.3 Abbreviations DGPS Differential Global Positioning System GPS Global Positioning System IMU Inertial Measurement Unit KHZ Kilohertz NGVD29 National Geodetic Vertical Datum of 1929 NAD83 North American Datum of 1983 POS MV Position and orientation system for marine vessels RTK Real Time Kinematic R2 Bathymetry System CMR+ Compact Measurement Record SFOBB San Francisco Oakland Bay Bridge SIM Sonar Interface Module SVP Sound Velocity Profile USACE US Army Corps of Engineers UTC Coordinated Universal Time WGS84 World Geodetic System of 1984 Page2

7 2. METHODS AND RESOLUTION LIMITATIONS 2.1 Survey Control Prior to survey operations, survey control at the project site was recovered based on NAD83, California Coordinate System Zone 3, and NGVD29 elevations. As the primary vertical control for this survey was provided by RTK global positioning system (GPS) observations, it was vital to the project to have an accurate ellipsoid separation model for on-the-fly conversion from the WGS84 ellipsoid (ellipsoid from which GPS heights are derived) to NGVD29. For this project, Mole (elevation 2.521m NGVD29 as provided by Caltrans) was used as the reference benchmark (Figure 2-1). Figure 2-1. Control benchmark (Mole). 2.2 Multibeam Bathymetry The R2 Sonic 2024 system was used to provide multibeam bathymetry coverage of the seafloor. The R2 Sonic 2024 transmits a shaped continuous wave pulse at the user selected frequency (200 KHz to 400 KHz). The transmit pulse is narrow in the along-track direction, but very wide in the across-track direction. The reflected acoustic energy is received via the R2 Sonic 2024 receivers. Within the receiver head, the beams are formed and the bottom detection process takes place. The resultant bottom detections (range and bearing) are sent via Ethernet deck lead to the Sonar Interface Module (SIM). The SIM then sends the data out to the sonic control software and the data acquisition software. Page3

8 The R2 Sonic 2024 works on user selectable frequency ranges so it is adaptable to a wide range of survey depths and conditions. The frequency can be selected on-the-fly without having to shut down the sonar system, change hardware, or halt recording data. This system produces a user selectable swath width of 10 to 160 using all 256 beams; the desired angle can be selected on-the-fly. The selected swath angle can also be rotated port or starboard while recording to direct the highly concentrated beams towards the desired target. Figure 2-2. R2 Sonic 2024 mounted on the vessel, Julie Ann. Sound velocity profile (SVP) data was acquired using the Odom Digibar Pro, a hi-tech composite sound velocity sensor. The Odom Digibar measures at a rate of 10 velocity and pressure observations per second, and responds to temperature changes immediately, maximizing its ability to identify and map thermoclines, a necessity for multibeam bathymetric data acquisition. The Applanix POS MV inertial navigation system was used to control motion and attitude for the R2 system. The POS MV delivers full 6-degree-of-freedom position and orientation solutions for marine survey vessels and outputs all motion variables at a high rate: position, velocity, heave, roll, pitch, true heading, acceleration vectors, and angular rate vectors. The system combines GPS/DGPS with rugged high-quality inertial sensors. The system measures true heading together will roll and pitch to 0.02 degree accuracy or better under dynamic conditions including hard turns and rapid acceleration and deceleration with heave accuracy of 5 centimeters or 5 percent all in real time. The POS MV system consisted of two GPS antennas mounted atop the vessel Julie Ann (primary port), a processor, version five, and an Inertial Measurement Unit (IMU) mounted centimeters directly above the transducer. Data was fed from the processor to Hypack via Ethernet at 200 hertz. Delayed heave and position data, used for the post-processing of data, were logged at 25 hertz. Page4

9 2.2.1 Positioning and Navigation Horizontal positions were acquired with a POS MV and RTK system. A base station was set up at the survey control with a Trimble R8 dual frequency GPS receiver in RTK mode. The unit transmitted Compact Measurement Record (CMR+) corrections to the POS MV system onboard the survey vessel to improve horizontal-vertical positioning to better than 0.5 meters (1.6 feet) and provide accurate inertial navigation through GPS outages for up to 30 seconds. Figure 2-3. R8 base station with survey vessel in the background. Position data was used in real time to provide navigation information to the vessel operator. A preliminary coverage plot with survey information was generated in real time to show survey coverage. The helmsman was presented with a plan view of the survey area with the vessel position and track. A color-coded swath of the water coverage was painted to the screen and used to navigate the survey vessel to fill the area. Water surface measurements were obtained by RTK GPS with on-the-fly ambiguity resolution. Real time water surface elevations obtained by RTK GPS onboard survey vessel Julie Ann were checked against water elevations observed in real-time Offsets Relevant sensor offsets were measured before the Julie Ann was deployed and input into Applanix POS MV in meters. All measurements were verified by two personnel. Offset setting files were saved in the project folder prior acquiring data. Page5

10 2.2.3 Calibration A patch test was completed each day as part of the system calibration procedures. The patch test used seafloor topology to bring multibeam swaths (run at varying speeds, headings, and overlaps) into coincidence. They are employed so that data can be corrected for timing latency, pitch, azimuth, and roll offsets, which may exist between the multibeam transducer and the IMU. Following this calibration, the POS MV quickly and automatically initialized itself upon power-up, outputting accurate navigation data. In addition, the system continuously monitored its sensors to ensure optimum performance. Figures 2-4 through 2-11 show the determination of the different bias (Roll, Latency, Pitch and Yaw) used during this survey. Roll. Figure 2-4. Roll Bias = 0⁰ Figure 2-5. Roll Bias Computation = -1.65⁰ Page6

11 Latency. Figure 2-6. Latency Bias = 0⁰ Figure 2-7. Latency Bias Computation = 0⁰ (no adjustment needed). Pitch. Figure 2-8. Pitch Bias = 0⁰ Page7

12 Figure 2-9. Pitch Bias Computation = -0.50⁰ Yaw. Figure Yaw Bias = 0⁰ Page8

13 Figure Yaw Bias Computation = 3.00⁰ Quality Control / Quality Assurance Quality Assurance Performance Test. A performance test was carried out to evaluate the quality and confidence of multibeam data being collected. Two sets of 4 parallel lines perpendicular to each other were surveyed utilizing a 90 swath to create a reference surface, and two perpendicular lines (check lines) using wider swath (140 ) were surveyed through the center of the reference area. Running the beam angle test we compared the check lines to the reference surface and obtained estimates of depth accuracy of the multibeam system at different angle limits. The resultant accuracy was used to determine the swath to utilize for data acquisition in order to meet USACE Hydrographic Survey specifications. For this project the results from the performance test (Table 2-1) indicate the multibeam system is providing reliable data out to +/- 70 beam width (140 full swath); however data acquisition for this project was achieved at 60 beam width (120 full swath). Figures 2-12 to 2-14 show the statistical results from the test. Page9

14 Figure Beam Angle Details: Statistical results of performance test with +/- 70 degrees. Figure Beam Angle Curve: Plot of statistical bias and confidence results at various beam angle widths. Page10

15 Figure Angle Test Report: Statistical bias and confidence results at various beam angle widths. Table 2-1. Performance Test Results Statistical Quantity Results from Survey 0.20 m Bin Size Maximum Outlier 0.18 m m Mean Difference (Reference Surface - Check Line) m 0.03m Depth Standard Deviation (1-σ) 0.03 m At 95% Confidence 0.05 m m Specs (per USACE Table 11.2) Water Level (Tides) in RTK Mode. Tidal information during the data acquisition was obtained via RTK methods. A base station was set up on our reference station (Mole). The water elevation obtained on the survey vessel (RTK) was cross-checked with water elevations measured directly in real-time with a R8 Rover in the project area at approximately half hour intervals during the data acquisition. Sound Velocity Casts. Velocity casts were taken during data acquisition at approximately 2 hour intervals (see Figure 2-15). Page11

16 Figure Example of a Sound Velocity Cast (02/27/2013) TPU (Total Propagated Uncertainties) Multibeam Report General Tuning Parameters Angular Coverage (deg) 120 Amplitude/Phase Measurement Crossover 12 Maximum Ping Rate (Hz) 20 Amplitude Detect Denominator 6 Along Track Beam Width (deg) 0.5 Across Track Beam Width (deg) 1.0 Estimation Graph Parameters Pulse Length (ms) 0.01 Number of Beams 256 Sector Steering Angle (deg) 80 Depth of Bottom (m) 20 Frequency (khz) 400 Roll Angle (deg) 3.0 Receive Bandwidth (khz) 6 Pitch Angle (deg) 3.0 Page12

17 Environment Speed of Sound (m/s) 1486 Sound Speed Sensor Uncertainty (m/s) 0.50 Peak-to-Peak Swell (m) 1.0 Surface Sound Speed Uncertainty (m/s) 0.25 F-A Seafloor Slope (deg) 0.0 Spatio-Temporal Variation (m/s) 1.00 P-S Seafloor Slope (deg) 0.0 Thickness of S-T Layer (m) 10.0 Water Level Uncertainty (m) 0.02 Sound Speed Uncertainty Beyond SV Profile 0.00 Spatial Tide Prediction Uncertainty (m) 0.02 Maximum Depth of SV Profile 10 Sensor Information Physical Offsets Sensor Offset Uncertainty Position MRU Transducer Position MRU Transducer Starboard Forward Vertical (+ Down) Survey Speed (kts) 3 Fixed Heave Uncertainty (m) 0.05 Speed Uncertainty (m/s) 0.1 Heave (% of Heave Amplitude) 5 Roll Offset Angle of Transducer (deg) -1.9 Roll Sensor Uncertainty (deg) 0.02 Pitch Offset Angle of Transducer (deg) 4 Pitch Sensor Uncertainty (deg) 0.02 Heading Offset Angle of Transducer (deg) 0.00 Roll Offset Uncertainty (deg) 0.05 Transducer Draft (m) 0.99 Pitch Offset Uncertainty (deg) 0.50 Yaw Offset Uncertainty (deg) 0.50 Positioning System Uncertainty (m) dmrs 0.1 Positioning Time Lag (ms) 0.05 Heading Uncertainty (deg) 0.1 MRU Time Lag (s) Transducer Time Lag (s) Draft Uncertainty (m) 0.02 Latency (s) Squat Uncertainty (m) 0.02 Loading Changes (m) 0.02 Page13

18 2.2.6 Processing For the bathymetry, the HySweep software package by Hypack, Inc. was used to process and bin the raw data sets by first applying acquisition specific variables such as vessel offsets, seawater sound velocities, vessel draft, system calibration (patch test), and delayed heave values and then editing the data to remove spurious soundings. The field-recorded raw sounding files were imported into HySweep and the acquisition variables were entered into the vessel configuration file. Once the sounding files were imported, the appropriate SVP file was then loaded into each line and the line corrected for sound refraction. Concurrent with SVP corrections, the bathymetry data was also corrected for dynamic vessel heave, pitch, and roll. The attitude, heading, navigation, and bathymetry data were then examined for noise and gaps. Nadir beam-filters were used to reject data from the outer reaches of the swaths. After each individual line was examined and cleaned in the HySweep Swath editor, the lines were merged. Adjacent overlapping lines of corrected bathymetry data were examined to identify any vertical offsets, data gaps, sound velocity, and motion errors. Any residual noise in the data set was also rejected at this time. After all data is filtered and processed, the final data set is binned to 3 ft x 3 ft cell size, using the average depth of all depths within the cell. The horizontal location of the representative average depth is the cell center. While processing, one notable area of mention is a debris field approximately 500 by 400 located on the southern side of the bridges (see Chart 1 of 2 Sun Illuminated for exact location). Figure Debris Field Page14

19 APPENDICES A B C D RESOURCES TECHNICAL SPECIFICATIONS OF SURVEY EQUIPMENT DIGITAL FILES CHARTS

20 A RESOURCES Personnel Party Chief Hydrographic Surveyor G. Suarez A. Tardif Survey Vessel Julie Ann Positioning Equipment Navigation Software Primary Positioning Differential Corrections HYPACK 2012a Applanix POS MV Real Time Kinematic (RTK) Vertical Reference RTK System Trimble R8 GPS Receiver Multibeam Bathymetry Primary System Motion Reference Unit Data Recording Sound Velocity Profiler The R2 Sonic 2024 Bathymetry System Applanix POS MV HYPACK/HYSWEEP 2012a Odom Digibar Appendix A

21 B TECHNICAL SPECIFICATIONS OF SURVEY EQUIPMENT Appendix B

22 Trimble R8 GNSS Receiver

23 Trimble R8 GNSS Receiver

24 High Resolution Multibeam Systems for: Hydrography Offshore Dredging Defense Research R2Sonic LLC 1503-A Cook Pl. Santa Barbara California, USA T: F: SONIC 2024 Multibeam Echo Sounder Features: 60kHz Wideband Signal Processing Focused 0.5 Beam Width Selectable Frequencies kHz Selectable Swath Sector 10 to 160 System Range to 500m Embedded Processor/Controller Equiangular or Equidistant Beams Roll Stabilization Rotate Swath Sector Applications: Hydrographic Survey Offshore Site Survey Pre & Post Dredge Survey Defense & Security Marine Research System Description: The Sonic 2024 is the world s first proven wideband high resolution shallow water multibeam echo sounder. With proven results and unmatched performance, the Sonic 2024 produces reliable and remarkably clean data with maximum user flexibility through all range settings to 500m. The unprecedented 60 khz signal bandwidth offers twice the resolution of any other commercial sonar in both data accuracy and image. With over 20 selectable operating frequencies to chose from 200 to 400 khz, the user has unparalleled flexibility in trading off resolution and range and controlling interference from other active acoustic systems. In addition to selectable operating frequencies, the Sonic 2024 provides variable swath coverage selections from 10 to 160 as well as ability to rotate the swath sector. Both the frequency and swath coverage may be selected on-the-fly, in real-time during survey operations. The Sonar consists of the three major components: a compact and lightweight projector, a receiver and a small dry-side Sonar Interface Module (SIM). Third party auxiliary sensors are connected to the SIM. Sonar data is tagged with GPS time. The sonar operation is controlled from a graphical user interface on a PC or laptop which is typically equipped with navigation, data collection and storage applications software. The operator sets the sonar parameters in the sonar control window, while depth, imagery and other sensor data are captured and displayed by the applications software. Commands are transmitted through an Ethernet interface to the Sonar Interface Module. The Sonar Interface Module supplies power to the sonar heads, synchronizes multiple heads, time tags sensor data, and relays data to the applications workstation and commands to the sonar head. The receiver head decodes the sonar commands, triggers the transmit pulse, receives, amplifies, beamforms, bottom detects, packages and transmits the data through the Sonar Interface Module via Ethernet to the control PC. The compact size, low weight, low power consumption of 50W and elimination of separate topside processors make Sonic 2024 very well suited for small survey vessel or ROV/AUV operations. Spec Sheet version 3.2 February Subject to change without notice

25 Sonic 2024 Multi Beam Echo Sounder Systems Specification: Frequency Beamwidth, across track Beamwidth, along track Number of beams Swath sector Max Range Pulse Length Pulse Type Ping Rate Depth rating Operating Temperature Storage Temperature Electrical Interface Mains Power consumption Uplink/Downlink: Data interface Sync In, Sync out GPS Auxiliary Sensors Deck cable length 200kHz-400kHz Up to m 10µs-500µs Shaped CW Up to 60 Hz 100m 0 C to 50 C -30 C to 55 C VAC, 45-65Hz <50W 10/100/1000Base-T Ethernet 10/100/1000Base-T Ethernet TTL 1PPS, RS-232 RS m Sonar Interface Module High Resolution Multibeam Systems for: Hydrography Offshore Dredging Defense Research Mechanical: Receiver Dim (LWD) Receiver Mass Projector Dim (LWD) Projector Mass Sonar Interface Module Dim (LWH) Sonar Interface Module Mass Sonar Options: 480 x 109 x 190 mm 12 kg 273 x 108 x 86 mm 6 kg 280 x 170 x 60 mm 2.4 kg Sonic 2024 Receiver Snippets Imagery Output Switchable Forward Looking Sonar Output Mounting Frame & Hardware Over-the-side Pole Mount Sound Velocity Probe & Profiler Extended Sonar Deck Cable, 25m or 50m 3000m Depth Immersion Depth Sonic 2022 Projector R2Sonic LLC 1503-A Cook Pl. Santa Barbara California, USA T: F:

26 APPLANIX POS/MV 320 POSITION & ORIENTATION SYSTEM FOR MARINE VESSELS A proven, high accuracy GPS aided Inertial Navigation System POS/MV is a GPS aided Inertial Navigation System (INS) that delivers full six degrees of freedom (position and orientation) solutions for marine vessels. POS/MV is now available in two specifications: POS/MV320 (accuracy to 0.01 ) and 220 (accuracy to 0.05 ). With RTK aiding, POS/MV will provide position accuracy to 0.01 (320) or 0.05 (220) in all dynamics and at all latitudes. The inertial component of POS/MV ensures continuity of all data during GPS dropouts enabling continued operation in high multipath environments and under or around significant obstructions. After power-up the Inertial Measurement Unit (IMU) becomes the primary source of navigation data. Noise and position errors from the GPS solution are not carried through to the output channel. GPS data is used only to correct the drift of the IMU. When the GPS position environment is good, the blended position from POS/MV will provide a lower noise, higher data rate solution that is available from GPS alone. The system comprises a compact IMU, rack mountable POS/MV Computer System (PCS) and two GPS antennas. The system is controlled and monitored via a Windows based software programme.interfacing to a RTK GPS receiver is easily achieved using standard NMEA messages. As an option POS/MV can be supplied with an internal RTK L1/L2 receiver. POS/MV has been designed to provide geo-referencing and motion correction data for any marine application. For the survey users, POS/MV eliminates the attitude errors associated with conventional motion sensors and gyrocompass in dynamic environments. Rapid deployment is achieved by a dynamic self-calibration routine. When commissioned power-up to full online capability takes 3 minutes - there is no gyro spin-up time System Attributes Roll & pitch accuracy to in all dynamics True heading accuracy to independent of latitude and dynamics Blended RTK position data to 2cm accuracy Complete navigation and attitude solution Continuity of all data during GPS dropouts No motion artefacts, even under the most severe conditions Roll & pitch accuracy to in all dynamics True heading accuracy to independent of latitude and dynamics Blended RTK position data to 2cm accuracy Complete navigation and attitude solution Continuity of all data during GPS dropouts No motion artefacts, even under the most severe conditions No gyro spin-up time Compact and reliable Eliminates post-processing for position errors Digital, analogue and ethernet interfaces Self-calibrating for rapid deployment Industry standard

27 Technical Specifications PERFORMANCE RTK DGPS Position m CEP m CEP Velocity 0.03 m/s 0.03 m/s Roll & Pitch True Heading Heave PHYSICAL 0.01 (4m baseline) 0.02 (2m baseline) 5% of Heave Amplitude or 5 cm 0.01 (4m baseline) 0.02 (2m baseline) Size IMU 204 x 204 x 168 mm PCS Antenna Choke Ring Weight IMU 3.5 Kg Power PCS Antenna Choke Ring 120/220 VAC, 60/50 Hz, 60W 441 x 111 x 346 mm 2.5U, 19" rack mount 170Ø x 77 mm (2 off) 370Ø x 61 mm (2 off) 7 Kg 0.37 Kg (2 off) 1.8 Kg (2 off) Temperature IMU -40 to +60 C PCS Antennas 0 to +60 C -40 to +60 C Humidity IMU 0 to 100% PCS Antennas 0 to 100% Cables IMU 8m (standard) INTERFACES Antenna 5 to 95% RH non-condensing 15m (2 off, standard) Ethernet Interface (10base-T) Function Operate POS/MV and record data Data UDP Ports IP Port Position, attitude, heading, velocity, track and speed, acceleration, status & performance, raw data. All data has time and distance tags. Display port - low rate (1Hz) data Data port - high rate (1-200Hz) data Control port - used by POS/MV controller RS232 Interfaces (D89 males) NMEA Port GGA, HDT, VTG, GST, ZDA, PASHR, PRDID (1-50Hz) High Rate Attitude Data Roll, pitch, true heading and heave in all Port multibeam proprietary formats (1-200Hz) Options Internal RTK GPS receiver Analogue interface (roll, pitch and heave) Field support kit

28 C DIGITAL FILES Description File Name Format Final Field Operations Report & Charts \Reports and Charts\ PDF ArcGIS Files \ArcGIS Data\ Map extents created from Plates 1-4 SFOBB_SurveyExtents.shp ESRI NGVD29 bathymetric contour shapefile SFOBB_Contours.shp ESRI MLLW bathymetric contour shapefile SFOBB_Contours_MLLW.shp ESRI Shapefile of pier numbers per Client request SFOBB_Piers ESRI NGVD29 bathymetric grid Bathy_SFOBB_Grd.tif GEOTIFF MLLW bathymetric grid Bathy_SFOBB_Grd_MLLW.tif GEOTIFF Sun Illuminated 3D Image - MLLW SFOBB Bathy 0.6f_NAD83_3f_MLLW_Blueish1.tif GEOTIFF Bathymetry Data \Bathymetry Data\ Processed MLLW XYZ data sorted at 3 feet intervals SFOBB_Bathy_3f_NAD83-3f_MLLW.xyz ASCII Processed NGVD29 XYZ data sorted at 3 feet intervals SFOBB_Bathy_3f_NAD83-3f_NGVD29f.xyz ASCII Microstation Files \Microstation Files\ Processed NGVD29 bathymetry points and contours in Microstation format NGVD29\ DGN Processed MLLW bathymetry points and contours in Microstation format MLLW\ DGN Appendix C

29 D CHARTS 1 BATHYMETRY CONTOURS (NGVD29), 1 OF 4 2 BATHYMETRY CONTOURS (NGVD29), 2 OF 4 3 BATHYMETRY CONTOURS (MLLW), 3 OF 4 4 BATHYMETRY CONTOURS (MLLW), 4 OF 4 5 SUN ILLUMINATED (MLLW), 1 OF 2 6 SUN ILLUMINATED (MLLW), 2 OF 2 Appendix D