OPR-0190-FA-22 West Prince of Wales Island, Alaska Vicinity of West of Prince of Wales Island, AK NOAA Ship Fairweather (S220) H13536 1 N/A Vicinity of Wolf Rock Alaska United States 20000 2023 CDR Meghan McGovern Basic Hydrographic Survey 2022-02-15 2022-09-18 2022-09-30 Multibeam Echo Sounder Multibeam Echo Sounder Backscatter meters UTM 8 Pacific 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 8N, 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 in the vicinity of Wolf Rock, Alaska. 55.129289 133.668615 54.818345 133.260043 Data were not acquired to the survey limits in accordance with the requirements in the project instructions and the 2022 NOS Hydrographic Surveys Specifications and Deliverables (HSSD). Complete survey coverage was not met initially due to operational time constraints. Additional coverage was lost due to GNSS equipment malfunctions which was only discovered following the conclusion of data acquisition, further reducing survey coverage as shown in the figure below (See section B.2.5). H13536 sheet limits (in blue) with survey coverage overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/3-Survey_Coverage/H13536_Survey_Coverage.PNG The area surrounding Prince of Wales Island is navigationally complex and home to communities that are inaccessible by land, relying instead on the sea as their primary means of travel. Waterways along the project area of Prince of Wales Island are marked by pinnacles, rocks, islets, and complex tidal currents. These hazards would not have been identified during prior surveys due to limitations of the technologies and techniques used at the time. These waterways are critical to the economic success of local coastal communities on Prince of Wales Island, as they are actively used for fishing and are the primary means for transporting goods throughout the region. Survey vintage in the southwestern Prince of Wales region dates back to 1916. The entire survey is adequate to supersede previous data. Data acquired in H13536 meets multibeam echo sounder (MBES) coverage requirements for complete coverage, as required by the HSSD. This includes crosslines (see Section B.2.1), NOAA allowable uncertainty (see Section B.2.10), and density requirements (see Section B.2.11). All waters in survey area Complete coverage Survey coverage was in accordance with the requirements listed above and in the HSSD. H13536 survey coverage overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/3-Survey_Coverage/H13536_Survey_Coverage.PNG S-220 0.0 720.16 0.0 0.0 0.0 0.0 0.0 32.1 0.0 0.0 720.16 0.0 0.0 0.0 0.0 0.0 32.1 0.0 4.5 0 0 0 0 100.6 2022-09-19 2022-09-20 2022-09-21 2022-09-22 2022-09-29 2022-09-30 Refer to the OPR-0190-FA-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. S-220 70.4 4.8 NOAA Ship Fairweather S-220 file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/1-Vessels/S220.jpg MBES Kongsberg Maritime EM 712 Conductivity, Temperature, and Depth Sensor AML Oceanographic MVP200 Positioning and Attitude System Applanix POS MV 320 v5 Sound Speed System Teledyne RESON SVP 70 The equipment installed on the survey platform S220 utilizes Kongsberg EM712 MBES, POS M/V v5 system, SVP 70, and AML Oceanographic MVP 200. Crosslines were collected, processed and compared in accordance with Section 5.2.4.2 of the HSSD. For adequate comparison, 4.5% of crossline to MBES data was acquired. To evaluate crosslines, a surface generated via data strictly from mainscheme lines and a surface generated via data strictly from crosslines were created. From these two surfaces, a difference surface (mainscheme - crosslines = difference surface) was generated (see figures below). Statistics show the mean difference between the depths derived from mainscheme data and crossline data was 0.02 meters and 95% of nodes falling within 0.99 meters. For the respective depths, the difference surface was compared to the allowable NOAA uncertainty standards. In total, 99% of the depth differences between H13536 mainscheme and crossline data were within allowable NOAA uncertainties. Overview of H13536 crosslines overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/4-Cross_Lines/Crossline_Overview.PNG Northern H13536 crosslines overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/4-Cross_Lines/Crossline_North.PNG Southern H13536 crosslines overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/4-Cross_Lines/Crossline_South.PNG H13536 crossline and mainscheme line difference statistics. file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/4-Cross_Lines/H13536_MB_VR_MLLW_MS_Final-H13536_MB_VR_MLLW_XL_Final_depth_delta.png ERS via VDATUM 0.0 0.132 S-220 0.0 1 0.5 In addition to the usual a priori estimates of uncertainty via device models for vessel motion and ERTDM/VDATUM/TCARI, real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H13536. Real-time uncertainties were provided via EM712 MBES data and 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. The measured MVP sound speed uncertainty used in the TPU calculation was 2.0m/s. Sheet H13536 junctions two surveys from prior projects, H12293 and H12741 as shown in the figures below. Data overlap between H13536 and each adjacent survey was achieved. The areas of overlap between H13536 and its junctioning surfaces were reviewed in CARIS HIPS and SIPs by surface differencing to assess surface agreement, but the comparisons were not made with surfaces of equal resolutions and the junction surfaces exceed the NOAA allowable uncertainty. For the junctions with H13536, a negative mean difference indicates H12741 was shoaler and a positive mean difference indicates H12293 was deeper. Overview of H13536 junctions overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/5-Junctions/H13536_Junction_Comparision.PNG Difference surface between H13536 (in gray), H12741 (in teal), and H12293 (in pink) overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/5-Junctions/H13536_Junction_Comparision-Zoom.PNG H12293 20000 2011 S221 N Surface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the surface from H13536 and the surface from H12293. The statistical analysis of the difference surface shows a mean of 0.30 meters with 95% of the nodes falling within a deviation of +/- 12.67 meters. It was found that 64.0% of nodes are within NOAA allowable uncertainty. Surface difference statistics between H13536 and H12293. file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/5-Junctions/H12293/H13536_MB_VR_MLLW_Final-H12293_MB_VR_MLLW_depth_delta.png H12741 20000 2015 S220 N Surface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the surface from H13536 and the surface from H12741. The statistical analysis of the difference surface shows a mean of -1.51 meters with 95% of the nodes falling within a deviation of +/- 7.06 meters. It was found that 49% of nodes are within NOAA allowable uncertainty. Surface difference statistics between H13536 and H12741. file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/5-Junctions/H12741/H13536_MB_VR_MLLW_Final-H12741_MB_16m_MLLW_depth_delta.png Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR. Applanix Logging Dropouts While logging POS data, several IMU discontinuities and positioning dropouts occurred over multiple days. These errors displayed in POSPac during post processing, and the issue was not known until the conclusion of acquisition. The multibeam data track lines associated with the POS data containing IMU discontinuity were deleted from the HIPS file and not used in creation of surfaces. Applanix was notified of the issue but could not give reasons on why it occurred frequently in H13536. None Exist There were no other factors that affected corrections to soundings. Minimum of one every four hours MVP casts were conducted at least once every four hours, guided by observations of the surface sound speed and targeted to deeper areas in accordance with Section 5.2.3.3 of the HSSD. All sound speed methods were used as detailed in the DAPR. H13536 cast locations (in black) overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/7-SVP_Data/Cast_Locations.PNG All equipment and survey methods were used as detailed in the DAPR. Holidays H13536 data were reviewed in CARIS HIPS and SIPS for holidays in accordance with Section 5.2.2.3 of the HSSD. 11 holidays which meet the definition described in the HSSD for complete coverage surveys were identified via Holiday Finder within the Pydro Explorer v22.1 QC Tools package. This tool automatically scans the surface for holidays as defined in the HSSD and was run in conjunction with a visual inspection of the surface by the hydrographer. Following the omission of MBES data without associated POS data (see Section B.2.5), 17 additional holidays were identified by the hydrographer as well as a large gap in coverage at 55° 09' 23.2525" N, 133° 34' 58.3293" W, and a smaller gap in coverage at 54° 47' 27.5234" N, 133° 21' 08.1821" W. The 28 holidays and two coverage gaps were not acquired in the field due to operational time constraints. H13536 holidays (in black) overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/8-Quality_Control/Holidays/Holiday_Locations.PNG NOAA Allowable Uncertainty The surface was analyzed using the HydrOffice QC Tools Grid QA feature in Pydro Explorer v22.1 to determine compliance with specifications. Overall, 99.5+% of nodes within the surface meet NOAA Allowable Uncertainty specifications for H13536 (see figure below). H13536 node uncertainty statistics. file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/8-Quality_Control/Uncertainty_Standards/H13536_MB_VR_MLLW_Final.GQv6.tvu_qc.png Density The surface was analyzed using the HydrOffice QC Tools Grid QA feature in Pydro Explorer v22.1 to determine compliance with specifications. Density requirements for H13536 were achieved with at least 99.5+% of surface nodes containing five or more soundings as required by HSSD Section 5.2.2.3 (see figure below). H13536 node density statistics. file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/8-Quality_Control/Data_Density/H13536_MB_VR_MLLW_Final.GQv6.density.png 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 .kmall files for Kongsberg systems. All backscatter were processed to GSF files and a floating point mosaic was created by the field unit via Fledermaus FMGT 7.10.3. See the figure below for a greyscale representation of the complete mosaic. A single resolution backscatter mosaic was created based on the specifications for a 100kHz system. All equipment and survey methods were used as detailed in the DAPR. H13536 backscatter mosaic overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/9-Backscatter/H13536_Backscatter.PNG CARIS HIPS and SIPS 11.4.26 QPS Fledermaus 7.10.3 NOAA Profile Version 2023 H13536_MB_VR_MLLW CARIS VR Surface (CUBE) Variable Resolution 22.6 227.7 NOAA_VR Complete MBES H13536_MB_VR_MLLW_Final CARIS VR Surface (CUBE) Variable Resolution 22.6 227.7 NOAA_VR Complete MBES Fliers The NOAA CUBE parameters defined in the HSSD were used for the creation of all CUBE surfaces for H13536. The surfaces have been reviewed where noisy data, or "fliers" are incorporated into the gridded surface, causing the surface to be shoaler or deeper than the estimated sea floor depth with the least uncertainty. The Flier Finder tool within the Pydro Explorer v22.1 QC Tools package was used to detect flagged targets which aided in the search for spurious soundings during gross cleaning. Where these spurious soundings cause the gridded surface to vary from the reliably measured seabed by values in excess of the maximum allowable Total Vertical Uncertainty at that depth, the noisy data were rejected by the hydrographer and the surface recomputed. Flier Finder was run iteratively until all remaining flagged targets were deemed to be valid aspects of the surface. After inspection by the hydrographer, 2384 flagged targets were determined to be valid aspects of the surface. H13536 flagged targets (in black) overlaid onto (Chart US3AK40M). file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/10-Fliers/Flier_Locations.PNG Per Section 5.2.2.1.3 of the 2022 Field Procedures Manual, no Horizontal and Vertical Control Report has been generated for H13536. Mean Lower Low Water ERS via VDATUM OPR-O190-FA-22_WPOW_100m_NAD83_2011-MLLW ERS methods were used as the final means of reducing H13536 to MLLW for submission. North American Datum 1983 (2011) Projected UTM 8 Vessel kinematic data were post-processed using Applanix POSPac processing software and RTX positioning 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 data acquisition, the S220 platform received correctors from the Wide Area Augmentation System (WAAS), with WAAS and SBETs being the sole methods of increasing positioning accuracy for H13536. Chart comparison between ENC and soundings from collected data. The soundings from H13536 are generally in agreement with the charted soundings of ENC US3AK40M. H13536 overview of survey coverage with associated soundings (in red) overlaid onto (Chart US3AK40M). Soundings displayed in units of meters. file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/11-Soundings/H13536_Sounding_Overview.PNG Northernmost closeup of H13536 survey outline with soundings (in red) overlaid with coverage onto ENC US3AK40M (in black). Soundings displayed in units of meters. file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/11-Soundings/H13536_Sounding_N.PNG Southernmost closeup of H13536 survey outline with soundings (in red) overlaid with coverage onto ENC US3AK40M (in black). Soundings displayed in units of meters. file:///M:/OPRO190FA22/Surveys/H13536/01_HDR/Reports/Descriptive_Report/Components/Images/11-Soundings/H13536_Sounding_S.PNG US3AK40M 229376 17 2022-01-28 2022-01-28 Shoals or potentially hazardous features exist for this survey, but were not investigated. Charted features exist for this survey, but were not investigated. No uncharted features exist for this survey. No channels exist for this survey. No Aids to navigation (ATONs) exist for this survey. Three Maritime Boundary Points were assigned for this survey, but were not addressed. Bottom samples were assigned for this survey, but were not acquired. 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. CDR Meghan McGovern Chief of Party 2023-11-06 LT Michael Card Operations Officer 2023-11-06 HST Garret Mayer Sheet Manager 2023-11-06