OPR-F324-FH-23 Approaches to Wilmington, North Carolina Wilmington, North Carolina NOAA Ship Ferdinand Hassler (S250) H13749 4 42 NM Southeast of Carolina Beach Inlet North Carolina United States 40000 2023 Commander William Winner, NOAA Navigable Area 2023-02-02 2023-09-09 2023-10-06 Multibeam Echo Sounder Multibeam Echo Sounder Backscatter meters UTC Atlantic Hydrographic Branch Any revisions to the Descriptive Report (DR) applied during office processing are shown in red italic text. The DR is maintained as a field unit product, therefore all information and recommendations within this report are considered preliminary unless otherwise noted. The final disposition of survey data is represented in the NOAA nautical chart products. All pertinent records for this survey are archived at the National Centers for Environmental Information (NCEI) and can be retrieved via https://www.ncei.noaa.gov/. Products created during office processing were generated in NAD83 UTM 18N, MLLW. All references to other horizontal or vertical datums in this report are applicable to the processed hydrographic data provided by the field unit. 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). NOAA The survey area is located near Wilmington, North Carolina approximately 42 NM Southeast of Carolina Beach Inlet. 33.606062 77.48235700000001 33.408363 77.200066 H13749 sheet limits (in blue) overlaid onto Chart US3SC10M. file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_Sheet%20Limits.png Data were acquired to the survey limits, shown in Figure 1, in accordance with the requirements in the Project Instructions and the March 2022 NOS Hydrographic Surveys Specifications and Deliverables (HSSD). The region around Wilmington, North Carolina experiences high vessel traffic transiting the eastern seaboard of the U.S. as well as traffic to and from the port. The Port of Wilmington has been updating its facilities expanding capacity in recent years, including the ability to handle two post-Panamax vessels concurrently, and in 2020, ranked 67 in tonnage of all U.S. ports, handling over 6,000,000 short tonnes of cargo.1,2,3 Numerous historic storms and hurricanes have impacted this region, potentially having changed the seafloor from the last surveys in the 1940s and 1960s. Additionally a portion of this project is in the top 10% of NOAA’s Hydrographic Health need emphasizing a high need for modern bathymetry for this area. This project will identify hazards and changes to the seafloor, provide critical data for updating National Ocean Service (NOS) nautical charting products, and improve maritime safety. It will also address data gaps to support the Seabed 2030 global mapping initiative. 1 https://usace.contentdm.oclc.org/digital/collection/p16021coll2/id/7447/rec/26 2 https://www.wect.com/2022/08/11/port-wilmington-receive-18-million-upgrade-increase-processing-rate/ 3 https://ncports.com/port-improvements/completed-upgrades/ The entire survey is adequate to supersede previous data. Data acquired on H13749 meet multibeam echo sounder (MBES) coverage requirements for complete coverage, as required by the HSSD, including NOAA allowable uncertainty (see Section B.2.2), and density requirements (see Section B.2.3). Exceptions are described in this report including sections B.2.1 (Crosslines) and B.2.11 (Holidays). All waters in the survey area Complete Coverage per HSSD Section 5.2.2.3 On DN 279, the ship suffered a season ending mechanical failure that forced its return to port. This kept the ship from surveying the entire assigned area to the sheet limits as seen in Figure 2. The area covered on H13749 was acquired with complete coverage multibeam, meeting the requirements listed above and in the HSSD, except as described in this report. H13749 survey coverage (2 meter surface) overlaid onto Chart US3SC10M file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_coverage.png S250 0.0 545.4 0.0 0.0 0.0 0.0 0.0 17.0 0.0 0.0 545.4 0.0 0.0 0.0 0.0 0.0 17.0 0.0 3.1 0 0 0 0 39.56 2023-09-09 2023-09-10 2023-09-11 2023-10-05 2023-10-06 Line 2023-252-0011 was a short erroneous line and was removed from the processed data. Refer to the OPR-F324-FH-23 Data Acquisition and Processing Report (DAPR) for a complete description of data acquisition and processing systems, survey vessels, quality control procedures, and data processing methods. Additional information to supplement sounding and survey data, and any deviations from the DAPR, are discussed in the following sections. S250 37.7 3.85 NOAA Ship Ferdinand R. Hassler file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/Ship.jpeg MBES Kongsberg Maritime EM 2040 MBES Backscatter Kongsberg Maritime EM 2040 Positioning and Attitude System Applanix POS MV 320 v5 Conductivity, Temperature, and Depth Sensor AML Oceanographic MVP200 Sound Speed System Teledyne RESON SVP 70 Crosslines were collected, processed, and compared in accordance with Section 5.2.4.3 of the HSSD. To evaluate crosslines, a 2 meter CUBE surface using strictly mainscheme lines, and a 2 meter CUBE surface using strictly crosslines were created. From these two surfaces, a difference surface (mainscheme - crosslines = difference surface) was generated using Pydro’s Compare Surfaces tool at a 2 meter resolution (Figure 4). Statistics show the mean difference between the depths derived from mainscheme and crosslines was 0.00 meters and 95% of nodes fall within 0.15 meters (Figure 5). For the respective depths, the difference surface was compared to the allowable NOAA uncertainty standards using Compare Surfaces. In total, 100% of the depth differences between H13749 mainscheme and crossline data were within allowable NOAA uncertainties (Figure 6). It should be noted that the ship was not able to acquire the required 4% of crosslines to mainscheme; only a 3.1% ratio was achieved. Additionally, the crosslines that were acquired did not cross every day of mainscheme. This was due to a season ending mechanical failure. Overview of H13748 crosslines. file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_XL_overview.png H13748 crossline and mainscheme difference statistics. file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MSonly-H13749_MB_2m_XLonly_depth_delta.png H13748 crossline and mainscheme NOAA allowable uncertainty statistics file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MSonly-H13749_MB_2m_XLonly_fracAllowErr_Freq.png ERS via VDATUM 0.126 S250 2 - 0.5 In addition to the usual a priori estimates of uncertainty provided via device models for vessel motion and VDATUM, real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H13749. Real-time uncertainties were provided via EM 2040 MBES data, Applanix Delayed Heave RMS. Following post-processing of the real-time vessel motion, recomputed uncertainties of vessel roll, pitch, gyro, and navigation were applied in CARIS HIPS and SIPS via a Smoothed Best Estimate of Trajectory (SBET) RMS file generated in Applanix POSPac. H13749 junctions with 2 surveys from prior projects, H12931 and H12934, as well as another sheet from this project, H13748, as shown in Figure 7. Data overlap between H13749 and each adjacent survey was achieved. To evaluate junction agreements, a BAG or CSAR surface from each junction surface was compared to a CSAR surface from H13749 with the same resolution. The multibeam data were also examined in CARIS Subset Editor for consistency and agreement. The junctions with H13749 are generally within the NOAA allowable uncertainty in their areas of overlap. For all junctions with H13749, a negative difference indicates H13749 was shoaler, and a positive difference indicates H13749 was deeper. Overview of H13749 junction surveys. file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_Junction%20Overview.png H12931 40000 2016 NOAA Ship Ferdinand R. Hassler SW Surface differencing using the Pydro Compare Surfaces tool was used to assess junction agreement between the 2 meter combined surface from H13749 and the 2 meter combined surface from H12931. A detailed graphical overview can be seen in Figure 8. The statistical analysis of the difference surface shows a mean of 0.11 meters with 95% of all nodes having a maximum deviation of +/- 0.13 meters, as seen in Figure 9. In addition, a comparison surface was created between the difference surface and the NOAA allowable uncertainty. It was found that 100% of nodes are within NOAA allowable uncertainty (Figure 10). Difference surface between H13749 (gray) and junctioning survey H12931 (blue) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749-H12931_Junction.png Difference surface statistics between H13749 and H12931 (2 meter surface) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MLLW-H12931_MB_2m_MLLW_Combined_Junction_depth_delta.png NOAA Allowable statistics between H13749 and H12931 (2 meter surface) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MLLW-H12931_MB_2m_MLLW_Combined_Junction_fracAllowErr_Freq.png H12934 40000 2016 NOAA Ship Ferdinand R. Hassler S Surface differencing using the Pydro Compare Surfaces tool was used to assess junction agreement between the 2 meter combined surface from H13749 and the 2 meter combined surface from H12934. A detailed graphical overview can be seen in Figure 11. The statistical analysis of the difference surface shows a mean of 0.11 meters with 95% of all nodes having a maximum deviation of +/- 0.13 meters, as seen in Figure 12. In addition, a comparison surface was created between the difference surface and the NOAA allowable uncertainty. It was found that 100% of nodes are within NOAA allowable uncertainty (Figure 13). Difference surface between H13749 (gray) and junctioning survey H12934 (color) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749-H12934_Junction.png Difference surface statistics between H13749 and H12934 (2 meter surface) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MLLW-H12934_MB_2m_MLLW_1of2_depth_delta.png NOAA Allowable statistics between H13749 and H12934 (2 meter surface) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MLLW-H12934_MB_2m_MLLW_1of2_fracAllowErr_Freq.png H13748 40000 2023 NOAA Ship Ferdinand R. Hassler SE Surface differencing using the Pydro Compare Surfaces tool was used to assess junction agreement between the 2 meter combined surface from H13749 and the 2 meter combined surface from H13748. A detailed graphical overview can be seen in Figure 14. The statistical analysis of the difference surface shows a mean of 0.00 meters with 95% of all nodes having a maximum deviation of +/- 0.25 meters, as seen in Figure 15. In addition, a comparison surface was created between the difference surface and the NOAA allowable uncertainty (See Figure 16). It was found that 100% of nodes are within NOAA allowable uncertainty. Difference surface between H13749 (gray) and junctioning survey H13748 (pink) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749-48%20Junction.png Difference surface statistics between H13749 and H13748 (2 meter surface) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MLLW-H13748_MB_2m_MLLW_Junction%20Comparison_depth_delta.png NOAA Allowable statistics between H13749 and H13748 (2 meter surface) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MLLW-H13748_MB_2m_MLLW_Junction%20Comparison_fracAllowErr_Freq.png Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR. None Exist There were no conditions or deficiencies that affected equipment operational effectiveness. Attitude Network Issue Data correction errors like those seen in Figure 17 were found throughout the survey. This error was determined to be caused by a networking issue between the POS MV and the Kongsberg EM2040 and, where the issue occurs, only affects a single ping. The errors caused by this issue and are very small and generally did not affect the gridded surface. Any erroneous soundings caused by this issue were rejected and the surface recomputed. Example attitude network issue on H13749 file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/Attitude%20issue.png Casts were conducted at a minimum of once every 4 hours during acquisition. MVP casts on S250 were guided by observation of the surface sound speed and targeted to deeper areas. All sound speed methods were used as detailed in the DAPR. All equipment and survey methods were used as detailed in the DAPR. NOAA Allowable Uncertainty The surface was analyzed using the HydrOffice QC Tools V3 Grid QA feature to determine compliance with specifications. Overall, 99.5% of nodes within the surface meet NOAA Allowable Uncertainty specifications for H13749 (Figure 18). H13749 Allowable uncertainty statistics file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MLLW_ALL_Final.GQv6.tvu_qc.png Density The surface was analyzed using the HydrOffice QC Tools V3 Grid QA feature to determine compliance with specifications. Density requirements for H13749 were achieved with at least 99.5% of surface nodes containing five or more soundings as required by HSSD Section 5.2.2.3 (Figure 19). H13749 Data density statistics file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_MB_2m_MLLW_ALL_Final.GQv6.density.png Holidays There are multiple holidays on sheet H13749. This occurred because the ship suffered a season ending mechanical failure and was unable to return to the survey grounds for clean up. These holidays are found at the edges of swaths where the subsequent line does not overlap the previous. The largest of these is 208m long and 11m wide at its widest point. For reference holidays are captured in the H13749_Holidays.000 submitted in the II_Supplemental_Records folder. All data reduction procedures conform to those detailed in the DAPR. All sounding systems were calibrated as detailed in the DAPR. Raw backscatter data were stored in the .all file for Kongsberg systems. All backscatter were processed to GSF files and a floating point mosaic was created by the field unit via Fledermaus FMGT 7.9.0 . See Figure 20 for a greyscale representation of the complete mosaic. Backscatter mosaic for H13749 file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_Backscatter.png CARIS HIPS and SIPS 11.4.25 NOAA Pydro 22.1 QPS Fledermaus 8.9 NOAA Profile Version 2023 H13749_MB_2m_MLLW.csar CARIS Raster Surface (CUBE) 2 NOAA_2m Complete MBES H13749_MB_2m_MLLW_Final.csar CARIS Raster Surface (CUBE) 2 18.0 40.0 NOAA_2m Complete MBES H13749_MBAB_2m_S250_300kHz_1of1.tiff MB Backscatter Mosaic 2 N/A Complete MBES The NOAA CUBE parameters defined in the HSSD were used for the creation of all CUBE surfaces in Survey H13749. The surfaces have been reviewed where noisy data, or "fliers," are incorporated into the gridded solutions causing the surface to be shoaler or deeper than the true sea floor. Where these spurious soundings cause the gridded surface to be shoaler or deeper than the reliably measured seabed by greater than the maximum allowable Total Vertical Uncertainty at that depth, the noisy data have been rejected by the hydrographer and the surface recomputed. Flier Finder, part of the QC Tools package within HydrOffice, was used to assist the search for spurious soundings following gross cleaning. Flier Finder was run iteratively until all remaining flagged fliers were deemed to be valid aspects of the surface. 2 fliers were highlighted by Flier Finder. These were determined by the hydrographer to be on a real feature of the bottom. Data Logs Data acquisition and processing notes are captured in field acquisition logs. Additional processing such as final tide, positioning, and sound speed application are noted a data log spreadsheet. Processed vs. raw line count comparisons are also completed in the data log. The hydrographer reviewed these documents to ensure proper correctors were applied to each line and all data issues are captured in this report. Per Section 5.2.2.1.3 of the 2020 Field Procedures Manual no Horizontal and Vertical Control Report has been generated for H13749. Mean Lower Low Water ERS via VDATUM OPR-F324-FH-23_NAD83_2011_VDATUM_MLLW.csar ERS methods were used as the final means of reducing H13749 to MLLW for submission. North American Datum 1983 Projected UTM 18 RTX Vessel kinematic data were post-processed using Applanix POSPac processing software and RTX methods described in the DAPR. Smoothed Best Estimate of Trajectory (SBET) and associated error (RMS) data were applied to all MBES data in CARIS HIPS and SIPS. During real-time acquisition, S250 received correctors from the Wide Area Augmentation System (WAAS) for increased accuracies similar to USCG DGPS stations. WAAS and SBETs were the sole methods of positioning for H13749 as no DGPS stations were available for realtime horizontal control. DN 253 GPS Week Issue Acquisition of POSMV data associated with MBES lines 0001 and 0002 began prior to midnight on DN253 (SEP 10). This caused a GPS week mis-match between the POS data and the MBES data for these two lines leading to the inability for Caris HIPS to process heave data manifesting as a heave artifact in the CUBE surface. To overcome this, POS delayed heave was reapplied to these lines manually in Caris HIPS setting the GPS week to SEP 03. Doing this allowed Caris to process the delayed heave for these lines. Afterwards, SBETs were reapplied and these lines re-georeferenced. The surface was recomputed confirming that the heave artifact was resolved. A comparison was performed between survey H13749 and ENC US3SC10M using CARIS HIPS and SIPS and a sounding layer derived from the 2 meter combined surface. The soundings were overlaid on the chart to assess differences between the surveyed soundings and charted depths. There were no contours to compare to on this chart. All data from H13749 should supersede charted data. In general, surveyed soundings agree with the majority of charted depths. H13749 soundings (orange) overlaid on ENC US3SC10M (purple) file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_Soundings.png US3SC10M 432720 37 2022-07-28 2023-08-17 No shoals or potentially hazardous features exist for this survey. No charted features exist for this survey. No uncharted features exist for this survey. No channels exist within the survey limits. No Aids to navigation (ATONs) exist for this survey. No Maritime Boundary Points were assigned for this survey. Bottom samples were assigned for this survey, but were not acquired due to the season ending mechanical issue. No overhead features exist for this survey. No submarine features exist for this survey. No platforms exist for this survey. No ferry routes or terminals exist for this survey. While observing the data, apparent ancient river beds and potential "Carolina Bays" were present. It is believed these originate from the last glacial maximum and benefit from Frying Pan Shoals protecting them from the shifting sands observed on adjacent surveys. Further research is on going with potential publications to result. The ship is scheduled to return to the area to continue to survey and delineate these features. Example ancient rivers found on H13749 file:///B:/OPR-F324-FH-23/Surveys/H13749/01_HDR/Reports/Descriptive_Report/Images/H13749_Rivers.png No present or planned construction or dredging exist within the survey limits. Further surveys are recommended in the area to support the delineation of the geologic features described in D.2.8. No new ENC scales are recommended for this area. 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 the attached survey data and reports. All field sheets, this Descriptive Report, and all accompanying records and data are approved. All records are forwarded for final review and processing to the Processing Branch. The survey data meets or exceeds requirements as set forth in the NOS Hydrographic Surveys Specifications and Deliverables, Field Procedures Manual, Letter Instructions, and all HSD Technical Directives. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required with the exception of deficiencies noted in the Descriptive Report. CDR William Winner Commanding Officer 2023-11-03 LT Patrick Debroisse, CMH CAT-A Operations Officer 2023-11-03