OPR-G322-TJ-24 Offshore Savannah Georgia H13851 Southern Approach to Tybee Roads Z 2024-04-22 2024-05-12 DOC/NOAA/NOS/OCS -- Office of Coast Survey hsd.chief@noaa.gov NOAA Ship Thomas Jefferson (S222) CC0-1.0 (NOAA Field Units) CC0-1.0 https://creativecommons.org/publicdomain/zero/1.0/ https://creativecommons.org/publicdomain/zero/1.0/legalcode These data were produced by NOAA and are in the public domain within the United States. NOAA waives any potential copyright and related rights in these data worldwide through the Creative Commons Zero 1.0 Universal Public Domain Dedication (CC0). H13851_MB_50cm_MLLW_1of1 Projected UTM 17 North American Datum 1983 (2011) Mean Lower Low Water found by multi beam Yes Yes 1.0m (Critical) N/A Yes Yes No 1m (Exceptional) N/A 0.15m (Exceptional) 0.75% (Exceptional/Critical) 369958000 S222 Positioning and Attitude System Applanix POS MV 320 v5 POS MV 320 V5 6497 2024-04-01 Multibeam Kongsberg Maritime EM 2040 EM2040 40260 200-400 kHz 2024-04-02 2024-04-03 Conductivity, Temperature, and Depth Sensor Sea-Bird Scientific SBE 19plus V2 SBE 19plus V2 19P60744-6667 n/a 2024-01-23 2024-04-01 Conductivity, Temperature, and Depth Sensor Sea-Bird Scientific SBE 19plus SBE 19plus 19P36399-4630 n/a 2024-01-17 2024-04-01 Conductivity, Temperature, and Depth Sensor AML Oceanographic MVP200 MVP-200 M12981 n/a 1901-01-01 1901-01-01 Conductivity, Temperature, and Depth Sensor AML Oceanographic MVP-X MVP-X CTD 9006 n/a 2022-02-08 2024-04-01 Sound Speed System Teledyne RESON SVP 70 SVP 70 0614179 n/a 2021-10-03 1901-01-01 Sound Speed System Teledyne RESON SVP 70 SVP 70 1013077 n/a 2024-01-09 1901-01-01 368926109 2904 Positioning and Attitude System Applanix POS MV 320 v5 POS MV 320 v5 8959 2024-03-26 Multibeam Kongsberg Maritime EM 2040 EM 2040 40122 200-400 kHz 2024-03-27 2024-04-04 Sound Speed System Teledyne RESON SVP 70 SVP 70 1921072 n/a 2024-01-10 1901-01-01 Conductivity, Temperature, and Depth Sensor Sea-Bird Scientific SBE 19plus SBE 19plus 19P33072-4472 n/a 2024-01-24 2024-04-01 Conductivity, Temperature, and Depth Sensor Sea-Bird Scientific SBE 19plus SBE 19plus 19P33589-4487 n/a 2024-01-24 2024-04-01 Conductivity, Temperature, and Depth Sensor SonTek CastAway-CTD CastAway-CTD CC2333002 n/a 2023-08-21 2024-04-01 366991449 DriX-12 Positioning and Attitude System iXblue Hydrins C7/AsteRx4 3028 2022-04-20 Multibeam Kongsberg Maritime EM 2040 EM2040 40270 200-400 kHz 2024-03-02 2024-03-27 Sound Speed System Valeport SWiFT SVP SWiFT SVP 80115 n/a 2022-01-02 1901-01-01 Sound Speed System Valeport SWiFT SVP SWiFT SVP 75334 n/a 2024-01-10 1901-01-01 Sound Speed System Valeport MiniSVS MiniSVS 50453 n/a 2022-01-03 1901-01-01 Pydro 22, a suite of software maintained by NOAA's Hydrographic Systems and Technology Branch (HSTB), contains various tools that aid in the analysis and quality control of hydrographic data. A Single Resolution (SR) 50 cm Combined Uncertainty and Bathymetry Estimator (CUBE) surface of this survey's mainscheme data and a SR 50 cm CUBE surface of this survey's crossline data were differenced with the Pydro 22 tool "Compare Grids." Vessels S222, 2904, and DriX-12 collected a combined total of approximately 92.74 linear nautical miles of MBES crosslines, a figure which constitutes about 4.00% of mainscheme mileage. A Single Resolution (SR) 50 cm Combined Uncertainty and Bathymetry Estimator (CUBE) surface of mainscheme data and a SR 50 cm CUBE surface of crossline data were differenced with the Pydro tool Compare Grids. The results of this comparison indicate that over 99.99% of grid-node comparisons between the two surfaces are within the Fraction of Allowable Error for depth/height, exceeding the specification of 95% stipulated by NOAA's 2024 Hydrographic Surveys Specifications and Deliverables (HSSD). The resulting mean of this comparison was a 0.00m difference, with a standard deviation of 0.06m, verifying the consistency of the data. A statistical summary of the comparison between H13851 crossline and maincheme data. file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Crossline%20Comparison/H13581_MB_50cm_MLLW_MS-H13851_MB_50cm_MLLW_XL_depth_delta_2024.png A statistical summary of the comparison between H13851 crossline and maincheme data. file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Crossline%20Comparison/H13581_MB_50cm_MLLW_MS-H13851_MB_50cm_MLLW_XL_fracAllowErr_vsDepth_Overview.png Statistical analysis of grid layers was conducted to assess the quality of the bathymetry. The "Grid QC" program contained within NOAA's Pydro 22 QC Tools was used to asses grid density, resolution, and uncertainty against allowable standards specified in the most recent edition of the HSSD. This survey was assigned quality metrics of General 1 and the delivered grids exceed the assigned quality metrics. The uncertainty metrics reported in the Metadata section reflect the highest Quality Metric that was achieved for each grid. Statistical analysis of grid layers file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Grid%20QA/H13851_MB_50cm_MLLW_Final.QAv7.density.png Statistical analysis of grid layers file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Grid%20QA/H13851_MB_50cm_MLLW_1of1.QAv7.tvu_qc.gn1.png After initial collection, MBES data underwent a thorough process of editing and inspection to clean gridded surfaces of erroneous fliers that inaccurately affected seabed measurements, and to ensure that no systematic errors were present. Teledyne's CARIS software was used to generate and examine a 50 cm CUBE surface as well as its uncertainty and standard deviation layers, which guided visual inspection for fliers. Designated soundings were selected to ensure that gridded surfaces honor the true depth of the seafloor specifically with regard to the least depths of new and existing charted features. Survey coverage was assessed daily by the field unit as part of night processing to identify data gaps to be addressed. Gaps in coverage that are larger than HSSD specifications are known as holidays. Various methods were utilized to aid in holiday identification including visual inspection and NOAA's Pydro 22 QC Tools "Holiday Finder". "Holiday Finder" is most commonly used for holiday identification in areas of 100% bathymetric (MBES) coverage. The hydrographer inputs a CUBE surface and the tool returns a number of files which can be used in Caris HIPS & SIPS for holiday analysis and acquisition planning. Multiple small holidays exist around the sheet edges due to operational time constraints. This entire survey is adequate to supersede previous data. The data in this survey was acquired in accordance with requirements set forth in the 2024 HSSD. N/A N/A Survey H13851 junctions with four surveys, H12961, H13853, D00279, and D00282. The Pydro 22 tool "Compare Grids" was utilized to assess the overlap of these junctions. The results of these junctions are shown in the statistics below. The results between H13851 and H12961 indicate that 91.23% of grid-node comparisons are within Fraction of Allowable Error standards for depth/height, thus failing to exceed the specification of 95% stipulated by NOAA's 2024 HSSD. However, the results of this comparison are likely skewed in relation to the 2017 H12961 survey due to the presence of annual dredging at the overlapping channel area - most recently in February, 2024. The resulting mean of this comparison was a -0.26m difference, with a standard deviation of 0.45m - falling outside the allowable TVU for the area. Yet, as shown below, once accounting for/removing the dredged area, 99.13% of grid-node comparisons are within the Fraction of Allowable Error standards for depth/height - thus passing the specification of 95% stipulated by NOAA's 2024 HSSD. The resulting mean of the adjusted comparison was a -0.15m difference, with a standard deviation of 0.13m which is within allowable TVU for the area. H13851 and H12961 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H12961/H13851_MB_50cm_MLLW_1of1-H12961_MB_50cm_MLLW_1of1_depth_delta_2024.png H13851 and H12961 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H12961/H13851_MB_50cm_MLLW_1of1-H12961_MB_50cm_MLLW_1of1_fracAllowErr_vsDepth_Overview.png H13851 (no channel) and H12961 overview file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H12961/H13851-D12961_JunctionComparison_NoChannel.png H13851 (no channel) and H12961 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H12961/H13851_MB_0.5_NoChannel-H12961_MB_50cm_MLLW_1of1_depth_delta_2024.png H13851 (no channel) and H12961 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H12961/H13851_MB_0.5_NoChannel-H12961_MB_50cm_MLLW_1of1_fracAllowErr_vsDepth_Overview.png The results between H13851 and H13853 indicate that 100% of grid-node comparisons are within Fraction of Allowable Error standards for depth/height, exceeding the specification of 95% stipulated by NOAA's 2024 HSSD. The resulting mean of this comparison was a -0.01m difference, with a standard deviation of 0.06m which is within allowable TVU for the area. H13851 and H13853 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H13853/H13851_MB_50cm_MLLW_1of1-H13853_MB_1m_MLLW_1of1_depth_delta_2024.png H13851 and H13853 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H13853/H13851_MB_50cm_MLLW_1of1-H13853_MB_1m_MLLW_1of1_fracAllowErr_vsDepth_Overview.png The results between H13851 and D00279 indicate that 99.98% of grid-node comparisons are within Fraction of Allowable Error standards for depth/height, exceeding the specification of 95% stipulated by NOAA's 2024 HSSD. The resulting mean of this comparison was a -0.07m difference, with a standard deviation of 0.05m which is within allowable TVU for the area. H13851 and D00279 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H13853/H13851_MB_50cm_MLLW_1of1-H13853_MB_1m_MLLW_1of1_depth_delta_2024.png H13851 and D00279 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H13853/H13851_MB_50cm_MLLW_1of1-H13853_MB_1m_MLLW_1of1_fracAllowErr_vsDepth_Overview.png The results between H13851 and D00282 indicate that 100% of grid-node comparisons are within Fraction of Allowable Error standards for depth/height, exceeding the specification of 95% stipulated by NOAA's 2024 HSSD. The resulting mean of this comparison was a -0.01m difference, with a standard deviation of 0.06m which is within allowable TVU for the area. H13851 and D00282 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H13853/H13851_MB_50cm_MLLW_1of1-H13853_MB_1m_MLLW_1of1_depth_delta_2024.png H13851 and D00282 junction statistics file:///B:/OPR-G322-TJ-24/Surveys/H13851/Metadata/QC/Junction%20Comparison/H13853/H13851_MB_50cm_MLLW_1of1-H13853_MB_1m_MLLW_1of1_fracAllowErr_vsDepth_Overview.png N/A The system echo sounders have the dynamic range to accommodate the relatively homogeneous survey area. The frequency was held constant at 300 kHz while the system automatically controlled pulse type. No special techniques were used outside of normal considerations for quality data acquisition for a bathymetric survey. Sound speed profiles were collected at the start of acquisition each day and at a minimum of once every four hours in order to apply appropriate absorption coefficients during acquisition. Please refer to Section 4.3.2.1.2 Acoustic Backscatter Imagery of the Field Procedures Manual 2020 for the backscatter post processing workflow. Information about uncertainty values used for data processing can be found within the Caris HIPS & SIPS processing project and in the associated Hydrographic Vessel Files (HVFs) for each survey platform. Uncertainty results for H13851 can be found in the Statistical Analysis section of Quality Control Procedures in this document. Pydro 22, a suite of software maintained by NOAA's Hydrographic Systems and Technology Branch (HSTB), contains the HDR Boost tool that aids in the creation and analysis of BAG files of the bathymetric data collected. The subsequent analysis report returned no warnings/sources of error. Trained Marine Mammal Observers list 2024-03-05 Coast Pilot Report 2024-07-05 Final Survey Outline 2024-06-04 NCEI Sound Speed Data 2024-05-17 As Chief of Party, field operations for this hydrographic survey were conducted under my direct supervision, with frequent personal checks of progress and adequacy. I have reviewed and approved all data and metadata. The survey meets or exceeds requirements as set forth in the Project Instructions and NOS Hydrographic Surveys Specifications and Deliverables. The survey is complete and no additional work is required with the exception of any deficiencies noted in the Report of Survey. CDR Megan R. Guberski Chief of Party