Chief of Party2021-10-14Olivia A. Hauser, CDR/NOAAField Operations Officer2021-10-14Dylan A. Kosten, LT/NOAAChief Survey Technician2021-10-14James B. JacobsonSheet Manager2021-10-14Joan M. Bonilla-PaganSenior Survey Technician2021-10-14B.D. JacksonAs 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.Multibeam Echo Sounder BackscatterMultibeam Echo Sounder2021-08-282021-08-21Navigable AreaUTC2021-06-07Olivia A. Hauser, CDR/NOAAPacific Hydrographic BranchAny 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 5N, MLLW. All references to other horizontal or vertical datums in this report are applicable to the processed hydrographic data provided by the field unit.2021metersNorth Coast Kodiak Island, AlaskaOPR-P336-RA-21NOAA Ship Rainier (S221)North Coast Kodiak Island1United StatesH13492Alaska40000Marmot StraitNOAADue to circumstances related to the COVID-19 pandemic, we were unable to complete survey acquisition within the entire assigned H13492 / H13493 areas. With approval from the Project and Navigation Managers, we prioritized the center of Marmot Strait and its eastern shore as the focus of our operations. Unfortunately, a deteriorating COVID-19 situation onboard prevented completion of this priority area or any additional H13493 coverage. The Project Manager advised us to combine H13492 / H13493 data into one survey (H13492) for submission. For further information, see Supplemental Records delivered with this report.\SupportFiles\H13492_Priorities.pngH13492 priority area as approved by Project Manager.152.28544758.404086151.92207258.125157This survey is referred to as H13492, "Marmot Strait" (sheet 1) within the Project Instructions. The originally assigned survey area was limited to the passage between Afognak and Marmot Islands. However, H13492 was expanded to include data initially acquired for survey H13493, Izhut Bay.\SupportFiles\H13492_H13493_Overview.pngH13492 / H13493 originally assigned survey areas (Chart 16580).\SupportFiles\H13492_H13493_Coverage.pngCombined H13492 / H13493 coverage submitted as H13492.Pydro QC Tools (v.3.4.7) Grid QA was used to analyze H13492 multibeam echosounder (MBES) data density. The submitted H13492 finalized variable-resolution (VR) surface met HSSD density and full coverage requirements as shown in the plots below.The entire survey is adequate to supersede previous data.\SupportFiles\H13492_MB_VR_MLLW_Final.QAv6.density.pngPydro derived plot showing HSSD density compliance of H13492 finalized variable-resolution MBES data.\SupportFiles\H13492_MB_VR_MLLW_Final.QAv6.pct_res.full_cov.pngPydro derived plot showing HSSD full coverage compliance of H13492 finalized variable-resolution MBES data.Last survey date is 08/28/2021 based on survey trackline data in the H13492 CARIS HIPS project. Survey end date also updated on the Hydrographic Title Sheet (Page 2).000000504.590000000099.71000S22100000192.3800028010000027.71000280200000184.790002803001432.0602021-08-212021-08-222021-08-232021-08-242021-08-252021-08-262021-08-272021-08-28The coastal waters around the northeastern end of the Kodiak Archipelago are identified as an area with a high need for modern hydrographic charting. The area is utilized by commercial and recreational fishing. It is transited by the Alaska Marine Highway System and commerce which is critical to the City of Kodiak and the US Coast Guard Base Kodiak. In spite of being an area with numerous bays, islands, islets, reefs and pinnacles, this coastal area from Shuyak Island to Izhut Bay has not been surveyed since the 1930s. This modern hydrographic survey will address gaps in the Seabed 2030 project, provide critical data to update National Ocean Service (NOS) nautical charting products, identify hazards and improve maritime safety. Data from this survey are intended to supersede all prior data in the common area. Due to ramifications from the COVID-19 pandemic, we were unable to complete the entire H13492 assigned survey area. We completed the central region of Marmot Strait where AIS data shows the highest level of vessel traffic occurs, and inshore to the safe limit of navigation along the east side of Afognak Island; this plan was approved by the Project Manager. H13492 nearshore survey operations were restricted by extensive kelp, as was the case during 1932 U.S. Coast and Geodetic Survey 5256 when, according to its Descriptive Report, "...the kelp was so heavy that it was impossible to penetrate with a launch..." Pydro QC Tools (v3.4.7) Holiday finder (v4) was used to identify gaps in MBES coverage. The program identified 73 holidays, the majority of which were small and located on or near the most inshore extents of coverage where kelp or acoustic shadows caused the gaps in coverage. Some gaps in coverage, especially those in offshore areas that might otherwise have been addressed, were not, due to schedule disruptions caused by the COVID-19 pandemic .Complete Coverage (Refer to HSSD Section 5.2.2.3)Inshore limit to 3.5 meters water depthNorth American Datum 1983Projected UTM 5Precise Positioning-Real time Extended (PP-RTX) processing methods were used in Applanix POSPac MMS (v8.5) software for post-processing horizontal correction of submitted H13492 MBES data.The Wide Area Augmentation System (WAAS) was used for real-time horizontal control during data acquisition.All submitted H13492 survey data were vertically referenced to the ellipsoid. An Ellipsoidal-Referenced Tidal Datum Model (ERTDM) was used for referencing H13492 data to MLLW and MHW.OPR-P336-RA-21_ERTDM21_NAD83-MLLW.csarOPR-P336-RA-21_ERTDM21_NAD83-MHW.csarERS via ERTDMMean Lower Low WaterAdditional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR.4.770.4S2211.18.828011.18.828021.18.82803\SupportFiles\RA-Alongside-Kodiak-HiRes-29Aug2021.jpgNOAA Ship RAINIER with survey launches onboard.All data for H13492 were acquired by NOAA Ship RAINIER and survey launches 2801, 2802 and 2803. The vessels acquired depth soundings, backscatter imagery and sound speed profiles. POS MV 320 v5ApplanixPositioning and Attitude SystemEM 710Kongsberg MaritimeMBESEM 2040Kongsberg MaritimeMBESMVP200ODIM Brooke OceanSound Speed SystemSBE 19plusSea-Bird ScientificConductivity, Temperature, and Depth SensorSVP 70Teledyne RESONSound Speed SystemRefer 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.Delayed heave failed to load on line 0003_20210824_214716_2801_300A_236. Our current ERS processing work flow overwrites delayed heave data, therefore the absence of heave on this line had no adverse effect. The line shows good agreement with adjacent data.Delayed Heave ApplicationTotal Propagated Uncertainty (TPU) values for survey H13492 were derived from a combination of fixed values for equipment and vessel characteristics, as well as from field assigned values for sound speed uncertainties. Tidal uncertainty was provided in metadata for the NOAA vertical datum transformation model used for this survey. In addition to the usual a priori estimates of uncertainty, real-time and post-processed uncertainty sources were also incorporated into the depth estimates of this survey. Real-time uncertainties for position, navigation, attitude, and vessel motion data from Applanix POS MV were applied during acquisition and initially in post-processing. POSPac SBET and RMS files were later applied in CARIS HIPS to supersede POS MV uncertainties associated with GPS height and position. Uncertainty values of the submitted finalized grids were calculated in Caris using "Greater of the Two" of uncertainty and standard deviation (scaled to 95%). Grid QA v6 within Pydro QC Tools was used to analyze H13492 TVU compliance. H13492 met HSSD requirements in 99.5+% percent of grid nodes, as shown in the histogram plot below.1S2210.0532801,2802,28030.050.14ERS via ERTDM0\SupportFiles\H13492_MB_VR_MLLW_Final.QAv6.tvu_qc.pngPydro derived plot showing TVU compliance of H13492 finalized multi-resolution MBES data.H13492 junctions with four contemporary surveys from the same project, OPR-P336-RA-21 (see figure below). Survey data were acquired on one of these four surveys, H13493, which was subsequently combined with H13492, therefore no junction comparison was performed.\SupportFiles\H13492_Junctions.jpgH13492 junction surveys (Chart 16580).Due to COVID-19 induced constraints discussed elsewhere in this report, no crossline data were acquired for this survey.Some H13492 MBES data were affected by adverse sea state and suboptimal sound speed correction as illustrated in the figure below. The conditions were encountered during ship (S221) survey operations in the northern part of Marmot Strait. We reviewed the affected data in subset editor and determined the offsets of up to approximately 0.2 meters, meet HSSD charting standards.Suboptimal sea state / sound speed correction\SupportFiles\H13492_Surface_Artifacts.pngExample area of H13492 MBES data affected by adverse sea state and suboptimal sound speed correction (vertical exaggeration = 10).Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR.Fifty seven sound speed profiles ("casts") were acquired for this survey at discrete locations within the survey area at least once every four hours, when significant changes to surface sound speed were observed, or when shifting survey operations to a new area. All sound speed profiles were concatenated into a master file and applied to H13492 MBES data using the "Nearest distance within Time" (4 hours) profile selection method.\SupportFiles\H13492_Casts.pngH13492 sound speed cast locations.All equipment and survey methods were used as detailed in the DAPR.Raw backscatter data were acquired as .ALL files logged during MBES operations and subsequently processed by RAINIER personnel. The .GSF files created during processing and backscatter mosaic data has been delivered with this report. Backscatter processing procedures are described in the DAPR.\SupportFiles\H13492_MBAB.pngOverview mosaic of H13492 multibeam acoustic backscatter coverage.CARIS VR Surface (CUBE)Variable ResolutionNOAA_VRComplete MBES0134.5H13492_MB_VR_MLLWCARIS VR Surface (CUBE)Variable ResolutionNOAA_VRComplete MBES-0.3134.5H13492_MB_VR_MLLW_FinalSubmitted H13492 surfaces were generated using NOAA recommended parameters for depth-based (Ranges) Caris variable-resolution bathymetric grids. Pydro Flier finder (v8) with default settings was used as a quality control check on submitted H13492 surfaces. After several iterations of data cleaning and running the tool, the program identified 23 potential fliers in the submitted surfaces. Subset analysis of the remaining potential fliers revealed them to be "false positives," a result of the dynamic seafloor making up some of the survey area. Flier finder was also used with the Noisy Edges option enabled with a resulting 6,599 potential fliers identified. This egregious number of potential fliers was identified by the program even after careful, meticulous surface edge cleaning. These results suggest that Flier finder with the Noisy Edges option enabled is not a reliable tool for assessing the quality of survey data and should not be used.QPSFMGT7.9.4NOAA Profile Version 2021CARISHIPS and SIPS11.3.15All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.No new ENC scales are recommended for this area.No Maritime Boundary Points were assigned for this survey.No platforms exist for this survey.The Tonki Cape Light, a skeleton tower with red and white diamond-shaped daymark, was observed in the field and appeared to be serving its intended purpose.\SupportFiles\H13492_ATON.jpgTonki Cape LightNo ferry routes or terminals exist for this survey.No abnormal seafloor or environmental conditions exist for this survey.No submarine features exist for this survey.No overhead features exist for this survey.No present or planned construction or dredging exist within the survey limits.Bottom samples were assigned for this survey, but were not acquired due to time constraints as explained elsewhere in this report.We recommend that the remainder of the originally assigned H13492 and H13493 survey areas be completed.This survey identified two Dangers to Navigation. They were submitted to the Marine Chart Division and have been applied to NOAA charting products. Details regarding the two DTONs are included the H13492 Final Feature File (FFF) and in Supplemental Records, submitted with this report. See image below for comparison of Chart 16604 before and after one H13492 DTONs was applied.\SupportFiles\H13492_DTON_1.pngChart 16604 before (left) and after (right) H13492 reported DTON was applied. Refer to section D.1.2 of this report regarding H13492 Dangers to Navigation.H13492 MBES coverage was acquired over a rock enclosed within a charted danger line approximately 3 nautical miles north of King Cove; the least depth was determined to be -0.28 meters (see figure below).\SupportFiles\H13492_Charted_Features1.jpgH13492 MBES coverage over rock charted (16604) within a danger line. Least depth -0.28 meters.Shoreline Feature Verification Due to time and personnel constraints imposed by the COVID-19 pandemic, shoreline feature verification was not fully conducted for this survey. Where possible, we used the Composite Source File (CSF) provided by NOAA HSD Operations Branch to address assigned features with S-57 attribution and record them in the H13492 Final Feature File (FFF) submitted with this report. This file includes new features found in the field as well as recommendations to update, retain or delete assigned features. Features that were not addressed are attributed as such and the reason stated.No channels exist for this survey. There are no designated anchorages, precautionary areas, safety fairways, traffic separation schemes, pilot boarding areas, or channel and range lines within the survey limits.US4AK5TM2018-03-012018-03-01778000