OPR-B360-KR-23 Nantucket Sound, MA Offshore of Nantucket Island, Martha's Vineyard, and Cape Cod, MA Ocean Surveys H13833 8 5 NM North of Muskeget Island Massachusetts United States 10000 2023 John R. Bean Navigable Area 2023-07-26 2023-11-05 2024-05-29 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 19N, 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 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 This survey provides hydrographic data for waters in Nantucket Sound, MA. The general locations of the survey limits are presented in Table 1. 41.472750000000005 70.34910099999999 41.396019 70.194902 Survey limits were acquired in accordance with the requirements in the Project Instructions and the HSSD. This project is located in Nantucket Sound, MA, a body of water between Cape Cod and the islands of Nantucket and Martha's Vineyard, MA. Surveying efforts will provide updated charting products and improve the hydrographic health of the region. The survey area has not been surveyed since the 1990s. Conducting a modern bathymetric survey in this region will identify hazards and changes to the seafloor and provide modern bathymetric data to update National Ocean Service (NOS) nautical charting products and support the Seabed 2030 global mapping initiative. The entire survey is adequate to supersede previous data. All waters in Sheet 1 Object Detection Coverage (Refer to HSSD Section 5.2.2.2) All waters in Sheets 2-8 Complete Coverage (Refer to HSSD Section 5.2.2.3) Survey coverage was in accordance with the requirements listed above and in the HSSD. Project OPR-B360-KR-23 coverage with H13833 emphasized. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833-Overview.jpg H13833 SSS coverage. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833-SSS.jpg MV Northstar Challenger 0.0 0.1 0.0 0.0 0.0 133.9 0.0 0.0 0.0 RV North Cove 0.0 41.4 0.0 0.0 0.0 109.1 0.0 0.0 0.0 RV South Cove 0.0 6.8 0.0 0.0 0.0 34.3 0.0 12.6 0.0 0.0 48.3 0.0 0.0 0.0 277.3 0.0 12.6 0.0 3.9 0 0 0 0 15.9 2023-11-05 2023-11-06 2023-11-07 2023-12-08 2024-02-11 2024-02-12 2024-05-29 Refer to the 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. MV Northstar Challenger 28.0 2.6 RV North Cove 11.1 0.8 RV South Cove 9.4 0.8 MV Northstar Challenger configured for survey operations. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/Vessel-CH.jpg RV North Cove configured for survey operations. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/Vessel-NC.png RV South Cove configured for survey operations. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/Vessel-SC.jpg MBES Teledyne RESON SeaBat T50-R SSS EdgeTech 4125 SSS EdgeTech 4200 Positioning and Attitude System Applanix POS MV 320 v5 Positioning System Trimble NetR9 Sound Speed System AML Oceanographic Micro SV-Xchange Conductivity, Temperature, and Depth Sensor AML Oceanographic MVP30-350 Conductivity, Temperature, and Depth Sensor AML Oceanographic AML-3 LGR Crossline mileage in H13833 totaled 3.9% of the mainscheme survey miles. Survey H13833 includes four submitted surfaces covering different time frames due to the movement of sand waves over the course of the survey, but a single mainscheme surface of all survey data was used for crossline comparison purposes. Despite the changes in bathymetry over time, agreement between crosslines and mainscheme bathymetry was very good, with a mean difference of 0.05 in the 1m resolution surface. Differences were greatest in areas of sand waves, where the bathymetry changed between crossline and mainscheme acquisition days. Crossline tracks overlaid on a coverage surface. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833-XL.jpg Depth differences between mainscheme and crossline data. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833_MB_1m_Main-H13833_MB_1m_XL_depth_delta.png ERS via VDATUM 13.06 MV Northstar Challenger 2 1 RV North Cove 2 1 RV South Cove 2 1 The HydrOffice "QC Tools" application was used to calculate TVU QC, determined by a ratio of uncertainty to the allowable error per NOAA and IHO specifications. Four surfaces covering different date ranges were finalized in CARIS HIPS using the "uncertainty" option to select the combination of a priori and realtime uncertainty estimates as the surface TVU source. The surfaces passed the uncertainty check, with 99.5+% or 100% of nodes meeting the uncertainty standards in each surface. A single combined surface of all data was also finalized and analyzed, and as the results were similar to each of the other submitted surfaces, only the single surface analysis is shown here for simplicity. Uncertainty standards, 1m resolution surface. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833_MB_1m_MLLW_1of5.GQv6.tvu_qc.png Survey H13833 junctions with a contemporary survey along its eastern border and a prior survey along part of its northern border. For H13833, and other surveys in this project with multiple submitted surfaces covering different date ranges, a single surface that includes all days of that survey was used for the junction comparisons. H13833 junction map with junction area depth differences. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833-Junction.jpg H12007 20000 2009 Thomas Jefferson W Prior survey H12007 is surrounded on 3 sides (eastern, southern, and western borders) by H13833; the northern border of H13833 has a rectangular cutout where H12007 is located. The eastern edge of the junction area shows evidence of significant sand wave shifting in the 14 years between the two surveys. The southern border between the surveys is slightly deeper now, with more sand wave shifts in the southwestern area as well. The western edge of the junction area is shoaler in the current survey than the prior survey. The mean depth difference is 0.15m, and 89% of comparison cells are within the allowable error fraction. The pattern of sand waves in the surface and the length of time between the two surveys make it likely that this is due to changes in bathymetry, not survey errors. Depth differences between H13833 and H12007. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833_MB_1m_MLLW-H12007_MB_1m_MLLW_combined_depth_delta.png Grid comparison, allowable error fraction. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833_MB_1m_MLLW-H12007_MB_1m_MLLW_combined_fracAllowErr_Freq.png H13827 10000 2023 OSI E This junction is discussed in the H13827 DR. 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. Sound Speed Variation Sound speed variations were observed throughout the survey area, correlating to factors including the tide, weather, water depth, and bathymetric features, such as slopes or sand waves. In data processing, sound speed profiles that did not adequately reflect the surrounding water mass were identified and removed, edited, or replaced. Sound speed casts were primarily applied using the CARIS HIPS "Nearest in Distance within Time" method, therefore, removing a profile collected on a steep slope would allow deeper and shoaler casts on either side to be applied instead. Casts that were empirically found to represent a large water zone were added at additional locations within that zone to ensure proper corrections given the cast selection options available in the CARIS sound speed tools. Bathymetry, uncertainty, and standard deviation surfaces were used to direct editing and determine the accuracy of sound speed cast selection. MV Northstar Challenger acquired MVP casts at approximately 20 minute intervals. An AML-3 LGR was also onboard the MV Northstar Challenger as a backup for the MVP, and AML casts were acquired at intervals of approximately 2 hours. RV North Cove and RV South Cove acquired AML3 casts at approximately 90 minute intervals. Hydrographers acquired more frequent sound speed profiles if high variability was noted in the surface sound speed from the AML Micro-X installed on the head of the transducer, or when the surface sound speed comparison threshold was exceeded (>2m/s change) between the profile reading at the draft of the transducer and the Micro-X. OSI submitted a data package titled "SOUND VELOCITY collected from MV Northstar Challenger, RV North Cove, and RV South Cove in North Atlantic Ocean, Nantucket Sound from 2023-10-18 to 2024-06-04" in NetCDF format to the National Centers for Environmental Information (NCEI) on August 7, 2024. H13833 sound speed cast locations. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833-SVP.jpg This survey was conducted to achieve Complete Coverage with 100% Side Scan Sonar and Concurrent Multibeam, as specified in HSSD 5.2.2.3, Option B. Complete multibeam coverage was used for feature developments and disprovals. The survey methods used to meet coverage requirements did not deviate from those described in the DAPR. The HydrOffice "QC Tools" application was used to verify that the multibeam data in each of the submitted surfaces met the density coverage requirements. All surfaces passed the check with 99% or more of the grid nodes populated with at least 5 soundings. For simplicity, the results shown below are only for a single surface including all the multibeam data, as the results were similar to the set of surfaces covering different date ranges. Most of the survey area had depths of less than 20m, for which a surface resolution of 1m is required. Approximately 7% of the survey area was deeper than 20m, with a maximum depth of 25m. The HSSD calls for a 2m resolution surface to cover these deeper areas. However, the data density of the 1m resolution surface was more than adequate even at these greater depths, and so to reduce the number of submitted surfaces, 1m resolution was used for the entire survey. Data density, 1m resolution surface. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833_MB_1m_MLLW_1of5.GQv6.density.png All data reduction procedures conform to those detailed in the DAPR. All sounding systems were calibrated as detailed in the DAPR. All equipment and survey methods were used as detailed in the DAPR. H13833 multibeam backscatter mosaic. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833-Backscatter.jpg NOAA Profile Version 2023 H13833_MB_1m_MLLW_1of5_Final CARIS Raster Surface (CUBE) 1 2.31 25.23 NOAA_1m Complete MBES H13833_MB_1m_MLLW_2of5_Final CARIS Raster Surface (CUBE) 1 3.11 23.93 NOAA_1m Complete MBES H13833_MB_1m_MLLW_3of5_Final CARIS Raster Surface (CUBE) 1 4.08 23.02 NOAA_1m Complete MBES H13833_MB_1m_MLLW_4of5_Final CARIS Raster Surface (CUBE) 1 2.31 25.23 NOAA_1m Complete MBES H13833_MB_1m_MLLW_5of5_Final CARIS Raster Surface (CUBE) 1 3.48 23.75 NOAA_1m Complete MBES H13833_MB_1m_MLLW_1of5 CARIS Raster Surface (CUBE) 1 2.31 25.23 NOAA_1m Complete MBES H13833_MB_1m_MLLW_2of5 CARIS Raster Surface (CUBE) 1 3.11 23.94 NOAA_1m Complete MBES H13833_MB_1m_MLLW_3of5 CARIS Raster Surface (CUBE) 1 4.08 23.02 NOAA_1m Complete MBES H13833_MB_1m_MLLW_4of5 CARIS Raster Surface (CUBE) 1 2.31 25.23 NOAA_1m Complete MBES H13833_MB_1m_MLLW_5of5 CARIS Raster Surface (CUBE) 1 3.48 23.75 NOAA_1m Complete MBES H13833_SSSAB_1m_600kHz_1of1 SSS Mosaic 1 N/A 100% SSS H13833_MBAB_2m_400kHZ_1of1 MB Backscatter Mosaic 2 N/A Processed Backscatter Survey H13833 was conducted over more than 6 months, with data collection days spread out due to weather conditions and survey priorities of the project. Over this time frame, significant changes were observed in the bathymetry as sand waves shifted and migrated. These changes were less apparent early in the survey, as mainscheme data was collected across the area with minimal overlap between days, but investigations and fills collected later in the survey showed larger differences from previous data. Per guidance from the NOAA OCS Project Manager, the submitted surfaces have been divided into groups of survey days to best reflect the bathymetry as observed. A surface inclusive of all data is also provided, showing artifacts of the changed bathymetry. Summary of dates included in each submitted MB grid. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833-surface-date-ranges.png Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR. Mean Lower Low Water ERS via VDATUM OPR-B360-KR-23_NAD83_VDatum_MLLW.csar OPR-B360-KR-23_NAD83_VDatum_MHW.csar North American Datum 1983 (2011) Projected UTM 19 Smart Base MACM CHATHAM MACM DARTMOUTH MADA FALMOUTH MAFA MANT NANTUCKET MANT PLYMOUTH MAPL TRURO MATU N001_NEWPORT_RI N001 Ocean Surveys Bass River OSBR US4MA43M 80000 27 2024-04-17 2024-05-09 US5MA41M 40000 16 2022-06-27 2023-12-19 Shoaling is evident in several areas across the sheet, particularly along the southern border where the charted contours do not match the surveyed depths. DTONS were submitted as sounding sets for 4 shoal areas in the survey. There were 3 charted wrecks in H13833, 2 of which were present and 1 was disproved. See the FFF for details. The southeast corner of the survey area contained 4 uncharted features, which may be wrecks or wreck debris. They are included in the FFF as obstructions or area wrecks, and an informational cartographic area in the FFF contains additional details about this group of features. Multiple new sand wave area features were delineated, as well as a water turbulence area. See the FFF for details. No channels exist within the survey limits. There were 4 ATONS charted in H13833, 1 marking a channel that is outside the sheet and 3 marking different shoals. All were found to be on station. No Maritime Boundary Points were assigned for this survey. No bottom samples were required for this survey. No overhead features exist for this survey. No submarine features exist for this survey. No platforms exist for this survey. Ferry routes between Nantucket Island and New Bedford or Martha's Vineyard cross through H13833. Ferries were observed by the field crews during the project. No ferry routes are shown on the charts for this survey. Most of the H13833 survey area contained sand waves of varying size, which were observed to have shifted over the course of the survey. Data collection days were spread over more than 6 months, due to weather conditions and survey priorities, and data collected later in the survey period show large differences from adjacent prior data. Observations of change are limited by the survey time frame, with fewer comparisons available in areas that did not have fills, reruns, or investigation lines collected later in the survey. Sand waves in the northeast area of the survey appeared more stable, with minimal changes over time. Greater changes were observed in all the named shoal areas of the survey, which are Cross Rip Shoal, Edwards Shoal, Norton Shoal, and Tuckernuck Shoal. Sand wave features covering these areas are included in the FFF. An area of water turbulence was also observed, and a new tide rips area is included in the FFF. The figure shows a cross section of a sand wave on two survey lines, data collected on DN 2023-309 (pink) and 2024-042 (cyan), at 5x vertical exaggeration. Water depths and horizontal distance are labeled in meters. Cross sectional view of a sand wave on different survey days with 5x vertical exaggeration. file:///B:/OPR-B360-KR-23/Surveys/H13833/01_HDR/Reports/Descriptive_Report/SupportFiles/H13833-shifted-sand-wave.png 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. John R. Bean Chief of Party 2024-10-30 David T. Somers Data Processing Manager 2024-10-30 Kelley J. Bostrom Sheet Manager 2024-10-30