OPR-F330-KR-22 Albemarle Sound Albemarle Sound Geodynamics H13758 2 Central Albemarle Sound North Carolina United States 5000 2023 Nicholas Damm, CH Navigable Area 2023-02-14 2023-02-28 2023-10-27 Multibeam Echo Sounder Multibeam Echo Sounder Backscatter Side Scan Sonar 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, LWD. 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 Contractors) CC0-1.0 https://creativecommons.org/publicdomain/zero/1.0/ https://creativecommons.org/publicdomain/zero/1.0/legalcode These data were produced under contract with NOAA and any potential copyright was assigned to NOAA. NOAA waives any potential copyright and related rights in these data worldwide through the Creative Commons Zero 1.0 Universal Public Domain Dedication (CC0). Contractor Geodynamics conducted a hydrographic survey in the assigned area of H13758 located in the central Albemarle Sound. Within H13758, all survey operations were conducted in accordance with the provided Statement of Work (SOW), Hydrographic Survey Project Instructions (PI), and the March 2022 National Ocean Service (NOS) Hydrographic Survey Specifications and Deliverables (HSSD). Any deviations from the aforementioned guidelines have been approved by the National Oceanographic and Atmospheric Administration (NOAA) Hydrographic Survey Division (HSD) Operations (OPS) branch and are documented in the survey correspondences. 36.174453888888884 76.16048405555556 35.95481241666667 75.92887783333333 Data were acquired to the survey limits in accordance with the requirements listed in the PI and the HSSD. Overview of project survey limits (H13758 shown in blue), overlaid onto Charts 11553, 12205, and 12206 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_Survey_Limits_Overview.jpg H13758 survey limits overlaid onto Charts 11553, and 12205 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_Survey_Limits_Sheet.jpg Albemarle Sound in North Carolina is a large, shallow, low-salinity estuary which extends approximately 50 nautical miles inland from the Outer Banks barrier islands. For this project, approximately 522 square nautical miles of modern, high-resolution hydrographic data will be collected in Albemarle Sound and connecting rivers. Commercial and recreational fishing as well as waterfront tourism are important economic drivers for the communities around the sound. Albemarle Sound has been facing recent and drastic decline in water quality and fishing stocks, and since the late 1980s, high levels of contaminants have been documented in the waters and biology of the sound and tributaries. To monitor this situation, the USGS and partners installed a network of monitoring stations as part of a program to study water quality to understand the sources and movement of nutrients and biota. The National Water Center along with the North Carolina Department of Environmental Quality have stated that there is a need for updated bathymetric data in the waterways to inform hydrodynamic models to improve understanding nutrient movement and to predict the effects of future sea-level and coastline change. Data collected by this survey will be used to characterize seabed habitat which will be used to help manage a healthy and sustainable seafood industry and help monitor future changes to the estuary ecology. This hydrographic survey will update NOAA National Ocean Survey (NOS) charts and products to identify hazards and improve navigation safety in a region which includes areas of high need for modern bathymetry based on the age of the prior data (1920) and the Hydrographic Health model. Survey data from this project are intended to supersede all prior survey data in the common area. The entire survey is adequate to supersede previous data. Survey quality in H13758 meets or exceeds requirements set forth in the HSSD. Survey quality was assessed through visual inspection, the analysis of crosslines, and utilizing QC Tools to assess uncertainty and density. Additionally, junction analyses were conducted between overlapping data collected on this project. For more information on methods and results of the survey data quality assessments for this survey, refer to section B.2 of this report. All waters in survey area Complete Coverage (Refer to HSSD Section 5.2.2.3). While best effort must be made to cover the SSS nadir gap, the specification requiring MBES data to extend completely across the SSS nadir gap is waived in depths less than 3.5m. The entirety of H13758 was acquired with complete coverage in accordance with section 5.2.2.3 Option B of the HSSD and coverage requirement adjustments listed in the PI, as shown in Figure 3. All efforts were made to acquire survey data to the sheet limits or to the Navigable Area Limit Line (NALL), as defined in section 1.3.2 of the HSSD. It should be noted that an exception to the depth that defines NALL, usually 3.5 m, was changed to 2 m at Low Water Datum (LWD) for this project and is stated as such in the PI. An example of where survey limits were defined by NALL due to safety can be seen in Figure 4. H13758 Complete Coverage SSS (greyscale) with MBES coverage, and assigned sheet limits in black. file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_Survey_Coverage.png Gap between H13758 survey coverage and sheet limits due to safety NALL met from above water fishing stakes which were submitted as a DTON in neighboring sheet H13762. file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_Gap_SheetLimits.jpg R/V 4Points 0.0 129.25 0.0 120.13 0.0 0.0 0.0 12.2 0.0 R/V Benthos 0.0 353.59 0.0 327.87 0.0 0.0 0.0 0.0 0.0 R/V Chinook 0.0 307.86 0.0 297.75 0.0 0.0 0.0 11.57 0.0 R/V Substantial 0.0 1566.18 0.0 1545.96 0.0 0.0 0.0 91.91 0.0 0.0 2356.88 0.0 2291.71 0.0 0.0 0.0 115.68 0.0 4.9 1 0 0 0 84.2 2023-02-28 2023-03-02 2023-03-03 2023-03-05 2023-03-06 2023-03-07 2023-03-08 2023-03-09 2023-03-10 2023-03-11 2023-03-12 2023-03-13 2023-03-16 2023-03-17 2023-03-18 2023-03-19 2023-03-20 2023-03-22 2023-03-24 2023-03-28 2023-03-29 2023-04-05 2023-04-06 2023-04-11 2023-04-12 2023-04-13 2023-04-14 2023-04-15 2023-04-28 2023-05-03 2023-06-15 2023-06-16 2023-06-18 2023-06-19 2023-06-25 2023-06-28 2023-06-29 2023-06-30 2023-07-01 2023-07-05 2023-07-06 2023-07-07 2023-10-20 2023-10-22 2023-10-23 2023-10-24 2023-10-27 Refer to the OPR-F330-KR-22 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. R/V 4Points 7.62 0.91 R/V Benthos 9.14 0.61 R/V Chinook 9.44 0.61 R/V Substantial 18.0 2.22 MBES Kongsberg Maritime EM 2040C SSS EdgeTech 4205 Positioning and Attitude System Applanix POS MV OceanMaster Sound Speed System AML Oceanographic MVP30-350 Sound Speed System AML Oceanographic BaseX2 Sound Speed System AML Oceanographic AML-3 LGR Sound Speed System AML Oceanographic MicroX SV All survey vessels utilized a dual-head Kongsberg EM 2040C multibeam system, a POS M/V OceanMaster positioning and attitude system, and an AML Oceanographic MicroX SV unit for surface sound speed. R/V Substantial utilized an AML MVP30-350 sound speed profiling system. R/V Benthos and R/V Chinook used an AML BaseX2 system for sound speed profiles, while R/V 4-Points utilized an AML-3 LGR. All vessels used the EdgeTech 4205 Sidescan Towfish for sidescan operations. Further details on equipment and software used can be found in the DAPR. Multibeam crosslines acquired for H13758 totaled 4.90% of mainscheme acquisition. H13758 crosslines were collected and analyzed in accordance with section 5.2.4.2 of the HSSD. Crosslines were evaluated in CARIS HIPS with a detailed visual inspection followed by a thorough statistical analysis. To conduct the statistical analysis, a 1 m CUBE surface was generated with strictly mainscheme data and another, separate 1 m CUBE surface was generated with only crossline data. The mainscheme and crossline surfaces were analyzed using the Compare Grids tool in Pydro Explorer, which generated a difference surface and associated statistics. In addition to the direct statistics from the surface differencing, the tool assessed the difference surface statistics and computed the proportion of NOS total allowable vertical uncertainty (TVU) consumed by the mainscheme to crossline differences per surface node. The statistical results of the difference comparison show 95% of nodes falling within +/- 0.06 m, with a mean difference of 0.00 m (Figure 5). Additionally, at least 95% of the difference surface nodes met or exceeded TVU specifications, as described in section 5.1.3 of the HSSD. H13758 crossline to mainscheme difference statistics file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_XL_1m_30JAN-H13758_MS_1m_30JAN_depth_delta.png ERS via VDATUM 0.0 0.08 R/V 4Points 2.00 N/A N/A 0.05 R/V Benthos 2.00 N/A N/A 0.05 R/V Chinook 2.00 N/A N/A 0.05 R/V Substantial N/A 2.00 N/A 0.05 The finalized CUBE surface was analyzed using the HydrOffice QC Tools Grid QA tool to assure 95% of the surface nodes meet TVU specifications. The results of the Grid QA tool determined that the finalized CUBE surface met or exceeded the TVU specifications, as shown in Figure 6. The multibeam surface was finalized with the computed uncertainty, derived from a mix of a priori and real-time uncertainty estimates, assigned as the uncertainty value. It should be noted that the uncertainty associated with the SEP model was applied in CARIS as the GPS Sounding Datum uncertainty, and not as Tide Zoning uncertainty. Additional details related to uncertainty methods may be found in the DAPR. In one area from Substantial day number 076, line 0009_20230317_042022_SU, the uncertainty exceeds the allowable limit. This exceedance was short in duration and did not result in any vertical shifts or misalignment with adjacent data. Though this area exceeds the allowable TVU, the artifact was not widespread and therefore the submitted grids meet the complete coverage requirements set forth in HSSD, with at least 95% of surface nodes meeting the allowable TVU specifications. Finalized 1 m CUBE surface TVU statistics for H13758 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_MB_1m_LWD_Final.GQv6.tvu_qc.png No junctioning surveys were provided for this project (see PI). However, H13758 junctions with H13755, H13760, H13761, H13762, and H13763 (Figure 7). Data overlap between H13758 and the adjacent surveys were attained. To conduct the junction analyses, similar to section B.2.1 of this report, the Pydro Compare Grids tool was utilized. The inputs for this tool were the surfaces for each individual survey. It should be noted for SBES CARIS Uncertainty surfaces the shoal layer was utilized for the analysis. In addition to the statistical results of the junction analyses, the resultant difference surfaces were visually inspected and CARIS HIPS Subset Editor was used to examine overlapping data for consistency, agreement between surveys, and confirming data met TVU specifications. Overview of H13758 junction surveys file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_Junction_Overview_wTitle.png H13755 5000 2023 Geodynamics E The statistical results of the difference comparison show 95% of nodes falling within +/- 0.08 m, with a mean difference of 0.00 m (Figure 8). Additionally, at least 95% of the difference surface nodes met or exceed TVU specifications, as described in section 5.1.3 of the HSSD. Junction analysis between H13758 and H13755 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_MB_1m_LWD-H13755_MB_1m_LWD_Final_Field_depth_delta.png H13760 5000 2023 Geodynamics W The statistical results of the difference comparison show 95% of nodes falling within +/- 0.08 m, with a mean difference of 0.01 m (Figure 9). Additionally, at least 95% of the difference surface nodes met or exceed TVU specifications, as described in section 5.1.3 of the HSSD. Junction analysis between H13758 and H13760 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_MB_1m_LWD-H13760_MB_1m_LWD_depth_delta.png H13761 5000 2023 Geodynamics N The statistical results of the difference comparison with the H13761 SBES shoal layer show 95% of nodes falling within +/- 0.08 m, with a mean difference of 0.03 m (Figure 10). Additionally, at least 95% of the difference surface nodes met or exceed TVU specifications, as described in section 5.1.3 of the HSSD. Junction analysis between H13758 and H13761 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/Junction%20Difference%20Between%20H13758%20and%20H13761_depth_delta.png H13762 5000 2023 Geodynamics S The statistical results of the difference comparison with the H13762 SBES shoal layer show 95% of nodes falling within +/- 0.08 m, with a mean difference of 0.03 m (Figure 11). Additionally, at least 95% of the difference surface nodes met or exceed TVU specifications, as described in section 5.1.3 of the HSSD. The statistical results of the difference comparison with the H13762 MBES show 95% of nodes falling within +/- 0.06 m, with a mean difference of 0.00 m (Figure 12). Additionally, at least 95% of the difference surface nodes met or exceed TVU specifications, as described in section 5.1.3 of the HSSD. Junction analysis between H13758 and H13762 SBES file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_MB_1m_LWD_Final-H13762_SB_Shoal_4m_depth_delta.png Junction analysis between H13758 and H13762 MBES file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_MB_1m_LWD_Final-H13762_MB_1m_LWD_Final_depth_delta.png H13763 5000 2023 Geodynamics NW The statistical results of the difference comparison with the H13763 SBES shoal layer show 95% of nodes falling within +/- 0.09 m, with a mean difference of 0.06 m (Figure 13). Additionally, at least 95% of the difference surface nodes met or exceed TVU specifications, as described in section 5.1.3 of the HSSD. The statistical results of the difference comparison with the H13763 MBES show 95% of nodes falling within +/- 0.11 m, with a mean difference of 0.00 m (Figure 14). Additionally, at least 95% of the difference surface nodes met or exceed TVU specifications, as described in section 5.1.3 of the HSSD. Junction analysis between H13758 and H13763 SBES file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_MB_1m_LWD_Final-H13763_SB_Shoal_4m_depth_delta.png Junction analysis between H13758 and H13763 MBES file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_MB_1m_LWD_Final-H13763_MB_1m_LWD_depth_delta.png Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR. Environmental influences affecting Sidescan imagery Throughout the duration of the survey, side scan acquisition frequently encountered environmental conditions which affected portions of the swath which would hinder the selection of contacts in the affected regions. The persistent challenging environmental influences were communicated with NOAA HSD OPS in the field and was additionally discussed with AHB prior to sheet submission (see project correspondence). These environmental conditions included numerous bait balls (biologic organisms suspended within the water column), vessel prop wash, and effects from water column stratification. The affected portions of side scan imagery which would be considered a holiday due to environmental effects were identified and reacquired with either side scan or multibeam bathymetry to meet the complete coverage requirements. The SSS lines that were reacquired frequently encountered similar environmental influences, and the final mosaic has been layered as best as possible to minimize the portrayal of artifacts. The side scan sonar mosaics are not free from environmental influences, but multiple methods were taken to ensure complete coverage was achieved and side scan sonar imagery was sufficient to identify a 1m x 1m x 1m target. More details on the methods used to ensure complete coverage, assess side scan sonar image quality, and clarifications on the final mosaics can be found in the DAPR and were additionally discussed in the pre-submission meeting with AHB (see project correspondence). Example of environmental influences affecting SSS imagery which were persistent throughout the survey area file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/58_SSS_Env_Influence1.png Example of the lines reacquired as infill for the environmental influences as shown above in figure 15 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/58_SSS_Env_Influence2.png Holidays in the SSS imagery due to the presence of environmental influences were often addressed with complete coverage MBES file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/58_SSS_Env_Influence_MBES.png Deviation from Sidescan Towfish Altitude Requirement Side scan towfish altitude reports were generated from all side scan navigation data in SonarWiz and examined to ensure compliance with the adjusted altitude specifications as outlined in the PI. Even with the allowable towfish altitude adjusted to 4-20% of the range scale in use (<8m of water depth), occasional deviations were identified. Any side scan lines which did not adhere to the adjusted altitude specifications were identified and the associated .tif images were re-exported from SonarWiz at a range scale which reduced the effective horizontal range to achieve compliance with the towfish altitude requirements. Recoveries were then completed as necessary. Approval of the .tif trimming method of addressing deviations from the towfish altitude requirements (as outlined in the PI), can be found in project correspondence. The challenges encountered while adhering to altitude specifications in very shallow water were communicated to NOAA HSD OPS, and as a result in depths of 2-3.5 m, where a narrow range scale is used (25 m), Geodynamics received guidance for allowance of operating the SSS towfish at an adjusted 3% of the range scale. In addition, Geodynamics was allowed to accept SSS data without trimming the effective imagery range scale for brief periods of altitude exceedances as long as altitude did not get lower than 3% of the range scale and the hydrographer believed imagery met coverage requirements. Communication and approval of deviations from the towfish height requirements as outlined in the PI, can be found in the project correspondence. Additionally, please see the DAPR for more information on side scan altitude quality control methods as well as more information on side scan .tif trimming. Multibeam echosounder ping drops On very rare occasion, it was observed that the multibeam echosounder would experience a "ping drop" issue which resulted in unexpectedly missing ping records, which were not observed by the survey vessel at the time of acquisition. An example of these ping drops are shown below in Figure 18. Any holidays in the resultant 1 meter resolution MBES surface were identified and reacquired, and no holidays resulting from these few and intermittent issues remain in the final delivered surfaces. Example of MBES ping drops observed from R/V 4-Points on DN 179 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_4P_PingDrops.jpg Lack of Delayed Heave Records in Positioning Data An issue where delayed heave was not recorded, was identified in one line of multibeam data from R/V Substantial on DN 078 (0002_20230319_004620_SU). The portion of this line for which delayed heave is missing shows up in the processed .hips file as a geo-referenced trackline, however no soundings from that period exist in Caris, and thus there was no effect to the bathymetric surface. The section of line with missing data was reacquired on a later date, and did not appear elsewhere in H13758. Recreational Fishing Gear Throughout the survey area, crab pots and other types of recreational fishing gear were observed or identified within the data, as seen in Figure 19. Particular attention was taken to avoid gear interactions and promote the safety of vessels and equipment, and at times defined the survey limits. Crab pots were identified within the sidescan sonar imagery or multibeam data, and were most often found to be of dimensions that did not warrant investigation. These objects were rejected from the multibeam data if they caused the surface to be pulled past TVU, but were otherwise not rejected. Please see the DAPR and section D.1.4 of this report for more information on fishing stakes. An example of a crab pot in SSS and multibeam data file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_Crabpot_Example.jpg None Exist There were no other factors that affected corrections to soundings. Sound speed casts were acquired at least once every four hours. Casts were often conducted more frequently than this time interval because of the dynamic water properties in the survey area. Additionally, the R/V Substantial utilized an MVP onboard which allowed for a higher frequency of casts. Surface sound speed was compared in real-time to the sound speed profile. When the comparison differed by more than 2 m/s, a new sound speed profile was acquired. Additionally, Hypack and Kongsberg SIS provided a real-time visual assessment of data quality (bathymetric grids, swath views) aiding the hydrographer in determining when a new cast was required. For more detailed information on sound speed methods, refer to the DAPR. All equipment and survey methods were used as detailed in the DAPR. Density The finalized CUBE surface were analyzed using HydrOffice QC Tools Grid QA tool to assure data met the required density specifications. Density requirements were achieved for the finalized surface in H13758 with at least 95% of the surface nodes (Figure 20) containing at least five or more soundings, exceeding the specifications required by section 5.2.2.3 of the HSSD. Finalized 1 m CUBE surface density statistics for H13758 file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_MB_1m_LWD_Final.GQv6.density.png Flier Finder In addition to a visual inspection, the CUBE surface was analyzed using HydrOffice QC Tools Flier Finder tool to assure data does not contain fliers (anomalous data as defined by QC Tools flier finding algorithms #2-5). While the Flier Finder tool flags surface fliers meeting a set criteria, it will also flag real surface features that meet the same criteria. Spurious soundings flagged by Flier Finder were cleaned until either no fliers remained or the remaining flagged fliers were deemed valid aspects of the surface. Holidays All CUBE surfaces were analyzed using HydrOffice QC Tools Holiday Finder to determine if the surfaces contained holidays, as described in section 5.2.2.3 of the HSSD. The tool scanned the CUBE surfaces, identifying any holidays, and generated an S-57 file to illustrate the locations of holidays. Another method of holiday evaluation was to visually pan the CUBE surfaces to identify holidays. The hydrographer would often alter the surface display (color ranges, symbology, shading) to help aid the hydrographer in identifying coverage gaps. The results reflected the same outcome as the tool. The primary source of data gaps in the multibeam surface were the result of dense bait balls which were additionally identified in the side scan imagery. These erroneous soundings were rejected by the hydrographer, were recovered with additional multibeam data, and are not reflected in the final surface. The side scan mosaic was extensively reviewed for coverage gaps or environmental influences which would prevent the detection of a 1m x 1m x 1m object. When identified, additional SSS or MBES data were acquired to meet complete coverage requirements. Additional information on data quality management can be found in the DAPR. 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 collected and stored within the .ALL files. Backscatter data were processed and reviewed for quality assurance in QPS FMGT. In accordance with the HSSD, GSFs and backscatter mosaics were exported from FMGT. Hydrographers in the field monitored backscatter intensities in real-time and made efforts to collect quality backscatter without hindering bathymetric data quality. Refer to the DAPR for more information on backscatter data acquisition and processing procedures. CARIS HIPS and SIPS 11.4.20 CARIS HIPS and SIPS 11.4.22 CARIS HIPS and SIPS 11.4.26 QPS FMGT 7.10.1 Chesapeak Technologies SonarWiz 7 7.10.02 NOAA Profile Version 2023 It should be noted the multibeam CUBE surface purpose is for SSS nadir gap coverage as well as fill and investigations. See DAPR for more details on the utilization of MBES. H13758_MB_1m_LWD_Final CARIS Raster Surface (CUBE) 1 1.86 6.25 NOAA_1m Complete MBES H13758_MB_1m_LWD CARIS Raster Surface (CUBE) 1 1.86 6.25 NOAA_1m Complete MBES H13758_SSSAB_1m_540kHz_1of2 SSS Mosaic 1 N/A 100% SSS H13758_SSSAB_1m_540kHz_2of2 SSS Mosaic 1 N/A 200% SSS H13758_MBAB_2m_4Points_300kHz_1of1 MB Backscatter Mosaic 2 N/A Complete MBES H13758_MBAB_2m_Benthos_300kHz_1of1 MB Backscatter Mosaic 2 N/A Complete MBES H13758_MBAB_2m_Chinook_300kHz_1of1 MB Backscatter Mosaic 2 N/A Complete MBES H13758_MBAB_2m_Substantial_300kHz_1of1 MB Backscatter Mosaic 2 N/A Complete MBES "H13758_SSSAB_1m_540kHz_1of2" represents the 100% complete coverage of the mainscheme acquisition sheetwide, while "H13758_SSSAB_1m_540kHz_2of2" is the 200% coverage required for feature disproval. All surfaces submitted are in compliance with the complete coverage requirements per section 5.2.2.3 Option B of the HSSD and the PI. In addition to the surfaces listed above, interpolated grids were generated and delivered in accordance with PI and guidance from NOAA HSD OPS. These additional grids are for the National Water Center deliverable and reflect _NAVD88 in their respective filenames. Reference the DAPR section C.1.4 for more information on interpolation and gridding methods, and the project correspondence for more information on National Water Center deliverables. Designated Soundings H13758 contains 24 designated soundings in accordance with sections 5.2.1.2.3 and 7.4 of the HSSD. These designated soundings were created to facilitate feature management and best represent the least depths of features in the Final Feature File (FFF). One exception to this includes one designated sounding selected over what is believed to be submerged debris within 5 m of a new obstruction observed above water (Unique ID: H13758_DTON_07). This designated sounding was included to ensure the grid represents this shoal feature but was not included as a new feature. In the finalized CUBE surfaces, the CARIS HIPS Apply Designated Soundings function ensured designated sounding depths are retained in the finalized surfaces. Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying DAPR. Low Water Datum ERS via VDATUM Albemarle_Sound_NAD83-LWD(LMSLxGeoid20B-0.5ft)_m.csar Real-time positional data were corrected with G2+ Global Navigation Satellite System (GNSS) satellite corrections provided by the Fugro Marinestar Satellite-Based Augmentation System (SBAS). To improve the accuracy of the real-time data, real-time position data were post-processed using Applanix POSPac Mobile Mapping Solution (MMS) software. Trimble CenterPoint RTX correction methods were used to create Smoothed Best Estimate of Trajectory (SBET) files, which were applied to the survey data in CARIS HIPS. For further information regarding processing and application of SBET and SEP files, please reference the DAPR. North American Datum 1983 (2011) Projected UTM 18 Real-time positional data were corrected with G2+ GNSS satellite corrections provided by the Fugro Marinestar SBAS. A detailed visual comparison was performed in CARIS HIPS between H13758 and the ENCs listed in Table 14 of section D.1.1. Sounding layers were generated from the CUBE surfaces and overlaid onto the ENCs to visually assess differences between the surveyed and charted depths. In addition to a detailed visual inspection, ArcGIS was used to quantify the difference between the extracted ENC sounding layers and the CUBE depth values. All soundings from the ENCs used in the visual chart comparison were downloaded as a shapefile from NOAA's ENC Direct to GIS application, and differenced with the surveyed depths from the 1 m surface in ESRI ArcPro. A statistical analysis of the difference comparison is shown in Figure 21. The surveyed depths from H13758 generally agree with the charted soundings from the largest scale ENCs within the survey area, with a mean difference of -0.48 m (ENC soundings shoaler on average). Due to the status of the outdated charts and potential risk of excessive bathymetric splits, guidance was provided by NOAA HSD OPS with allowance to omit bathymetric splits when a charted sounding between survey lines was shoal of the surveyed data. Data were reviewed in comparison to the chart but also between surveyed depths, conducting bathymetric splits at hydrographer's discretion. Please see project correspondence and the DAPR for further information on this topic. H13758 statistical analysis of surveyed depths to charted soundings file:///B:/OPR-F330-KR-22/Surveys/H13758/01_HDR/Reports/Descriptive_Report/SupportFiles/H13758_ENC_ChartComparison.jpg US5NC54M 40000 19 2023-03-15 2023-12-11 US4NC53M 80000 38 2023-08-29 2024-01-25 US5NC52M 40000 16 2021-10-27 2024-02-05 No significant shoals were identified to be hazardous in H13758. Seven DTONs were reported and forwarded to MCD, and are added to the FFF appropriately with Special Feature Type as 'DTON'. One submitted and accepted DTON (Unique ID: H13758_ANTI_DTON_02) later became an ANTI-DTON and is addressed appropriately in the FFF (more information below). Refer to the FFF for the remarks and recommendations for each feature. See DR Appendix II Supplemental Records for the submitted DTON reports and related correspondence with the NOAA HSD OPS. Two additional DTONs were submitted to AHB, but were not reported and have been included in the FFF (Unique IDs: 2_039_2 / 2_040_2, and 2_038_1). Please see section D.2.1 of this report for more information regarding those features. DTON 01 was a wreck with the mast exposed at the surface and was found by visual observation at the time it was reported. The area was later surveyed with side scan sonar, and the imagery was used to position the wreck. The position of this feature changed slightly from the position that was reported and is detailed as such in the FFF. DTON 02 was submitted as an exposed pile or stump at the surface, however subsequent investigations at a later time found that the stump was no longer visible at the surface. A 150 m disproval was conducted with complete coverage MBES, and no feature was detected. In agreement with NOAA HSD OPS, an ANTI-DTON report was submitted in accordance with section 1.6.4 of the HSSD, and accepted by AHB. This feature is addressed in the FFF (Unique ID: H13758_ANTI_DTON_02) with a description of "Delete". See DR Appendix II Supplemental Records for related correspondence. Disprovals of charted features within areas that were surveyed with SSS coverage requirements were either conducted or attempted. In agreement with NOAA HSD OPS, all disproval search radii were addressed with consideration of the re-scheme chart scale and were of at least 150 m. When a feature was detected within this radius, completing the disproval was not required and the new feature was addressed as New/Delete. Please reference correspondence for more information on disprovals for this project. One assigned charted feature (Unique ID: 2_004_2) was identified in the side scan sonar imagery but was not further developed with MBES due to safety considerations. The obstruction is submerged and appropriately charted, positioned between two ATONs that were observed to be on station and serving their intended purpose. This feature has been addressed in the FFF with a description of "Retain". All assigned charted features within H13758 are detailed in the FFF in accordance with section 7.3 of the HSSD. Two new wrecks (Unique IDs: 2_009_1 and 2_011_1) were identified that did not meet the vertical minimum size requirements for new features at the surveyed depth as defined by sections 7.3.2 and 5.2.2.3 of the HSSD. Due to the potential anthropogenic significance of these features, the uncharted wrecks were included in the FFF to be left up to cartographic discretion. One feature was identified outside the sheets limits in neighboring sheet, H13755. This feature was investigated and is addressed in the H13755 FFF, in accordance with section 7.3 of the HSSD. Throughout the survey area, uncharted fishing stakes and pound nets were observed at the surface and identified in the side scan sonar and bathymetric data. In agreement with NOAA HSD OPS, when identified as contacts or within bathymetric data, these features were developed accordingly with MBES to obtain a least depth when safe and practicable, and have been included in the FFF as new obstructions. In the southeast area of the sheet, the sheet limits were not met due safety concerns regarding fishing stakes extending from the shoreline into H13758. This area was reported as a DTON in neighboring sheet H13762, as the majority of the feature was located within H13762. Three submerged fishing stakes that were identified at the end of this area, located in H13758 and were developed with MBES and included in the FFF (Unique ID: 2_041_1). In agreement with NOAA HSD OPS, heights were not calculated for above water features, and the TECSOU and WATLEV for these features were attributed as "Unknown" and QUASOU as "Depth Unknown" in the FFF. More information on these features can be found in section D.1.2 of this report and related correspondence with NOAA HSD OPS can be found in DR Appendix II Supplemental Records. With respect to the aforementioned deviations, all new features found within H13758 are detailed in the FFF in accordance with section 7.3 of the HSSD. See DR Appendix II Supplemental Records for related correspondence with NOAA HSD OPS. No channels exist within the survey limits. One charted ATON, Albemarle Sound Warning Daybeacon A (Unique IDs: 2_039_1 and 2_040_1), was observed to be in a position different than charted. The position of the observed ATON matched the coordinates listed in the USCG Light List, and therefore was not reported as a discrepancy but was submitted to the branch as a DTON though not reported. This daymark and beacon with the observed position has been included in the FFF (Unique IDs: 2_039_2 and 2_040_2) as a new feature. The charted ATON, Albemarle Sound Light 1AS, was observed to be damaged and replaced with a green can lighted buoy. A discrepancy report was submitted to the USCG, and both features were reported to the branch as DTONs. The damaged ATON was submitted as an obstruction DTON (Unique ID: H13758_DTON_07) and the buoy was not submitted to MCD but is included in the FFF (Unique ID: 2_038_1) as a new feature. With exception of the aforementioned ATONs, all other ATONs located within H13758 were found to be on station and serving their intended purpose. Please see DR Appendix II Supplemental Records for all related correspondence. No Maritime Boundary Points were assigned for this survey. One bottom sample was acquired in accordance with section 7.2.3 of the HSSD and described in the FFF. 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. No abnormal seafloor or environmental conditions exist for this survey. No present or planned construction or dredging exist within the survey limits. No new surveys or further investigations are recommended for this area. 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. Nicholas Damm, CH Chief of Party 2024-03-17 Data Acquisition and Processing Report 2024-03-17 Coast Pilot Report 2024-03-08