No Maritime Boundary Points were assigned for this survey.Two bottom samples locations were assigned in the PRF. Samples were successfully retrieved at both locations. Sticky gray mud were the primary constituents in both samples. Samples were photographed but not retained. Refer to the FFF submitted with the survey deliverables for results.No new ENC scales are recommended for this area.No new surveys or further investigations are recommended for this area.Ice scour features caused by wind-driven pack ice dragging on the seafloor are relatively common in the area. The linear features are ephemeral and not navigationally significant, usually resulting in no more than 1 m of vertical relief from the surrounding seafloor.No overhead features exist for this survey.No Aids to navigation (ATONs) exist for this survey.No ferry routes or terminals exist for this survey.No platforms exist for this survey.No present or planned construction or dredging exist within the survey limits.No submarine features exist for this survey.No charted features exist for this survey.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.The chart comparison was performed by examining the best-scale Electronic Navigational Charts (ENCs) that intersect the survey area. The latest edition(s) available at the time of report compilation were used. The chart comparison was accomplished by overlaying the finalized BASE surface(s) with shoal-biased soundings and the final feature file (FFF) on the charts in CARIS HIPS. The general agreement between charted soundings and survey soundings was then examined and a more detailed comparison was undertaken for any shoals or other dangerous features. In areas where a large scale chart overlapped with a small scale chart, only the larger scale chart was examined. When comparing to survey data, chart scale was taken into account so that 1 mm at chart scale was considered to be the valid radius for charted soundings and features. Results are shown in the following sections. It is recommended that in all cases of disagreement this survey should supersede charted data. USCG Notice to Mariners (NM) and USCG Local Notice to Mariners (LNM) for District 17 from week 27/2020 through 38/2020 were checked. No items were found that affected the survey area. Note that ENC metadata and non-specific geographic area objects on the ENCs that overlap the survey area were not investigated.Soundings from this survey (blue) overlaid on soundings from the charts (black). Units are in meters.SupportFiles\Sounding_Comparison.jpgThere are few charted soundings overlapping the project area, but general agreement is excellent, with all agreeing to 0.5 m or better. No shoaling or deepening trends are apparent.2018-07-1892019-09-30300000US3AK83M2018-09-18112020-01-07400000US3AK80MNo shoals or potentially hazardous features exist for this survey. No DTONs were submitted.No uncharted features exist for this survey.The Wide Area Augmentation System (WAAS) was used for real-time horizontal control during data acquisition. All real-time positions were replaced in final processing with post-processed kinematic (PPK) positions generated in Applanix POSPac software, as described previously.Projected UTM 3Post-processing of all navigation data was done in Applanix POSPac MMS (v8.4) software. Initial processing was done in the field using Trimble PP-RTX methodology. Following completion of operations and availability of precise ephemeris data, navigation data was reprocessed in POSPac using Applanix SmartBase (ASB) methodology to achieve better overall results than the initial PP-RTX method, and applied to all survey data. ASB processing was possible because the project area was fully encompassed by a network formed by three or more CORS base stations. ASB processing was further facilitated by the presence of the nearby stations at St. Michael (AT01) and Unalakleet (AB17). ASB processing replaced all initial PP-RTX positions. Therefore, all final data is corrected with ASB. Exceptions, if any, were noted previously in this report. Note: The area is within UTM zone 4N, but 3N was used for projection instead. This was done to simplify operations by keeping all survey sheets under OPR-R385-KR-20, which laid mostly in 3N, in a common UTM zone.AT01StMichael AK2018BET1Bethel WAASAC31BaldHead Ak2006AC07Buckland AK2007AB17Unalakleet AK2008AB09Razorback AK2007AB04Mekoryuk AK2008AB04Savoonga AK2007Smart BaseRTXNorth American Datum 1983Mean Lower Low WaterAll soundings were reduced to MLLW using the ERTDM NAD83 to MLLW separation model grid file provided by NOAA using ERS methodology. Tide gauges and ERTDM validation sites (GPS buoys) were installed as part of the overall project but were not used for reduction of soundings. Gauge data and validation results have been separately provided to NOAA CO-OPS. Reports (with accompanying data packages) that have been submitted directly to CO-OPS are itemized in Section E of this report. Discrete tide zones were generated using project gauge data but were not used for sounding reduction. Zones were used for an ERZT comparison to the provided ERTDM grid, with the two methods having an overall agreement of 0.02 m with a standard deviation of 0.12 m. Zones are provided in the Water Levels directory. Additional detail is available with the project HVCR.OPR-R385-KR-20_ERTDM_NAD83-MLLW_04162020.csarERS via ERTDMAdditional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR.2020-07-299468151 Stebbins Install Report2020-07-319999771 Norton Sound Buoy Install Report2020-07-319999770 St Michael Install Report2020-09-109469031 Koyuk Install Report2020-10-149999776 Eastern Norton Sound Buoy Install Report2020-10-179999771 Western Norton Sound Buoy Removal Report2020-10-18Final Summary Report for OPR-R385-KR-20 Norton Sound2020-10-20Survey Outlines for OPR-R385-KR-202020-10-219468151 Stebbins Removal Report2020-10-229999776 Eastern Norton Sound Buoy Removal Report2020-10-289469031 Koyuk Removal Report2020-10-309999770 St Michael GNSS-R Analysis Report2020-11-09NCEI Sound Speed Profile Data Submission2020-11-30MMO Training and Observation Logs2020-12-04Coast Pilot Review Report for OPR-R385-KR-20Lead Hydrographer2021-01-12Thomas MorinoCharting Program Manager2021-01-12Andrew Orthmann, C.H.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 2019 NOS Hydrographic Surveys Specifications and Deliverables, Hydrographic Survey Project Instructions and Statement of Work. 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, if any, noted in the Descriptive Report.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 equipment and survey methods were used as detailed in the DAPR.GPS Vertical BustsAlthough vertical agreement is generally very good, vertical busts attributable to GPS positioning error between crosslines or overlapping mainscheme are apparent sporadically in the data set. These are normally less than 0.20 m of vertical separation. Any that approached or exceeded IHO Order 1a were investigated and addressed in processing. All crosslines pass within IHO Order 1a, and final surfaces are within allowable TVU for the depth.Graphic showing survey Junctions.SupportFiles\H13374_Survey_Junctions.jpgThis survey did not junction other contemporary surveys.None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.All equipment and survey methods were used as detailed in the DAPR.Crossline LNM totaled 10.2% of mainscheme. Effort was made to ensure crosslines had good temporal and geographic distribution, were angled to enable nadir-to-nadir comparisons, and that the required minimum percent of mainscheme LNM was achieved. Crosslines were conducted with both vessels to ensure there was ample overlap for inter-vessel comparisons, with each vessel crossing the other's mainscheme lines. Since the two vessels worked in close proximity and normally ran parallel lines, crosslines were collected in sets whenever both vessels were in simultaneous operation. The collection of crosslines in sets while spreading sets out across the survey area for good distribution led to incidental collection of additional crossline LNM beyond the required 8% of mainscheme. Crosslines were often collected while transiting across the survey area to reach a different survey priority such as bottom sample locations or infills, leading to crosslines that were diagonal to the direction of mainscheme lines. The crossline analysis was conducted using CARIS HIPS “Line QC Report” process. Each crossline (with all associated file segments) was selected and run separately through the process, which calculated the depth difference between each accepted crossline sounding and a "QC" BASE (CUBE-type) surface’s depth layer created from the mainscheme data. The QC surface was created with the same parameters and resolution used for the final surface, with the important distinction that the QC surface did not include crosslines so as to not bias the results. Differences in depth were grouped by beam number and statistics were computed, including the percentage of soundings with differences from the QC surface falling within IHO Order 1a. When at least 95% of the sounding differences exceed IHO Order 1a, the crossline was considered to “pass,” but when less than 95% of the soundings compare within IHO Order 1, the crossline was considered to “fail.” A 5% (or less) failure rate was considered acceptable since this approach compares soundings to a surface (instead of a surface to a surface), allowing for the possibility that noisy crossline soundings that don't adversely affect the final surface could be counted as a QC failure in this process. Lines selected as crosslines and their percentage (%) of soundings passing IHO Order 1a, sorted from highest passing to lowest, are listed below. 3871-ASV-CW5-254-E1_XL06 -- 100.0% pass 3873-ASV-CW5-254-E1_XL04 -- 100.0% pass 0855-Q105-254-E1_XL02 -- 100.0% pass 0856-Q105-254-E1_XL03 -- 100.0% pass 0858-Q105-254-E1_XL05 -- 100.0% pass 3869-ASV-CW5-254-E1_XL01 -- 99.9% pass Results: Agreement between them mainscheme surface and crossline soundings is excellent. At least 95% of crossline soundings compare to the mainscheme surface within IHO Order 1a for all crosslines. Refer to Separate II: Digital Data for the detailed Crossline QC reports.2 hoursSound speed profiles or "casts" were acquired aboard the Q105 while underway with a Teledyne Oceanscience RapidCAST system, which utilized a Valeport SWIFT sound speed profiler. The ASV was not equipped with a sound speed profiler. Surface sound speed at the sonar head was monitored continuously and a new cast was collected when the surface speed varied from the previous profile's speed at the same depth by greater than 2 m/s, leading to a cast interval of approximately 2 hours. Casts were taken as deep as possible. On survey lines with significant differences in depth, the deeper portion of the line was favored to ensure that changes across the full water column were measured. The cast data was used to correct the sounding data for both vessels, using the "nearest in distance within time" (set to 2 hours) within CARIS HIPS.Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR.The uncertainty layer of the final surface was examined in CARIS HIPS, as well as analyzed in Pydro QC Tools V3.2.13 Grid QA v6. Uncertainty of the final grid cells range from 0.289 to 0.515 m. 100% of grid cells have TVU falling within the allowable range by depth. Largest values were observed to be in areas of highly variable seafloor where many soundings of different depths contribute to the value of the relatively large ( 4 m ) grid cell, resulting in a higher standard deviation for the grid cell. All final grid cells are within specifications. Qualifier 10510.02500.135ERS via ERTDMNone ExistThere were no other factors that affected corrections to soundings.The survey vessels were outfit for MBES data collection with similar survey equipment. Both vessels utilized Reson Seabat T-50 MBES systems, except the Q105 was configured with a dual-head setup while the ASV-CW5 used a single-head system. Both vessels used Applanix POSMVs for attitude and position measurements (Oceanmaster on the Q105, Wavemaster II on the ASV). Sound speed profiles were collected using Valeport rapidProSV and SWIFT sensors (deployed using a Teledyne Oceanscience RapidCast system) from the Q105 only.Teledyne RESONSeaBat T50-RMBESTeledyne RESONSeaBat T50-RMBES BackscatterApplanixPOS MV 320 v5Positioning and Attitude SystemTeledyne OceansciencerapidCASTSound Speed SystemValeportSWiFT SVPSound Speed SystemASV-CW5 (foreground), and Qualifier 105 (background).SupportFiles\Vessels.jpgQualifier 1051.832ASV-CW50.55.5The Qualifier 105 (Q105) is a 32 m aluminum-hull vessel owned and operated by Support Vessels of Alaska. The Q105 acquired multibeam data and provided housing and facilities for on-site data processing. The vessel was also used to collect bottom samples, deploy/recover tide buoys, conduct sound speed casts, conduct feature investigations via skiff/UAS, and deploy/recover the ASV-CW5 vessel. The ASV-CW5 (ASV) is a 5.5 m aluminum-hull Autonomous Surface Vessel (ASV), C-Worker 5 model, owned and operated by L3-Harris ASV. The ASV was operated in an unmanned but monitored mode, collecting multibeam data in close proximity to the Q105.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.NOAA Extended Attribute Files V2020.3CARIS Raster Surface (CUBE)H13374_MB_4m_MLLW_FinalMBES Set Line Spacing0804NOAA_4mMB Backscatter MosaicH13374_MBAB_1m_400kHz_1of1MBES Set Line Spacing0801N/AThe final depth information for this survey was submitted as a CARIS BASE surface (CSAR format) which best represented the seafloor at the time of the 2020 survey. The surface was created from fully processed data with all final corrections applied. The surface was created using NOAA CUBE parameters and resolutions by depth range in conformance with the 2019 HSSD. The surface was finalized, and designated soundings were applied where applicable. Horizontal projection was selected as UTM Zone 3 North, NAD83. A non-finalized versions of the CSAR surface is also included which does not have a depth cutoff applied. This does not have the "_Final" designation in the filename. An S-57 (.000) Final Feature File (FFF) was submitted with the survey deliverables as well. The FFF contains data not readily represented by the final surface, including bottom samples and shoreline verification results (if any). Each object is encoded with mandatory S-57 attributes and NOAA Extended Attributes (V2020.3). A georeferenced multibeam backscatter mosaic (Geotif format in NAD83 UTM Zone 3N, 1 m resolution) was also produced and provided with the survey deliverables. Note that backscatter processing and mosaic generation was not a requirement and the mosaic is provided as-is. The mosaic may have flaws or holidays which could be addressed through further processing. However, it is of sufficient quality to show the relative changes in seafloor type across the survey area.All sounding systems were calibrated as detailed in the DAPR.All data reduction procedures conform to those detailed in the DAPR.Image showing overview of survey coverage.SupportFiles\H13374_Survey_Coverage.jpgThe entire survey is adequate to supersede previous data.The area serves as the approach to the community of Unalakleet. In addition, the Project Instructions describe the purpose of the project as follows: This project will provide contemporary data to update National Ocean Service (NOS) nautical charting products and services and increase maritime safety and commerce in the region. The Hydrographic Health Model and Automatic Identification Systems (AIS) traffic patterns identify this area as a hotspot where vessels are transiting in close proximity to the seafloor. This area was also identified as a high priority survey area by external stakeholders who identified the area extending from east of St. Michael Island to southwest of Egg Island as an area of refuge used by vessels transiting the Bering Sea. In addition, Stephens Pass between St. Michael and Stuart Islands was also identified as a travel lane for local shallow draft fishing traffic. The survey area includes the remote coastal communities of Stebbins (Yup'ik name: Tapraq) and St. Michael, both located on Saint Michael Island. These villages rely on coastal shipping as a primary source of income, supplies, and fuel. This survey will improve the safety of the maritime traffic and services available to these communities by improving the quality of existing bathymetric data in the area, which currently predates the 1890s. Tide gauges will also be installed to provide tide data in an area currently underserved with tide observations. This will help improve tide predictions and fulfill further objectives of the Alaska Water Level Watch program. Survey data from this project is intended to supersede all prior survey data in the common area.Survey limits were acquired in accordance with the requirements in the Project Instructions and the HSSD.ASV-CW5000007.853.200Qualifier 105000008.2103.500000001610.2156.700This survey was one of six completed under project OPR-R385-KR-20, with project-wide on-site hydrographic operations running from July 5 through September 17, 2020. Dates listed are for this survey only.2020-09-092020-09-10200025.7Image showing overview of survey extents.SupportFiles\H13374_Survey_Extents.jpgThe survey area is located in Norton Sound, Alaska, approximately 100 nautical miles southeast of Nome. The area is off the road system and relatively remote. The small communities of the region are accessible only by air or sea. Navigation through the area is limited to the summer and fall seasons due to the presence of sea ice for the majority of the year. The reliable ice free season is normally June through October, with ice likely to be encountered in May and November. Navigation is normally not possible for most vessels from December through April. The closest communities to the survey area are Stebbins (pop. 571 in 2018), St. Michael (pop. 415 in 2018), and Unalkaleet (pop. 697 in 2018). Nome (pop. 3,866 in 2018) is the hub community for the region, with daily flights to Anchorage (weather permitting). Transient traffic consists mostly of barges that bring supplies to the nearby communities. Local vessel traffic is mostly skiffs engaged in subsistence activities or travel between communities. The area is relatively shallow (14 m on the west end to 10.2 m on the east end) and has a gradual slope towards shore. The seafloor of the area is largely featureless but has occasional linear ice scours. Bathymetric data collection was carried out in September of 2020 under project OPR-R385-KR-20, with final processing and reporting carried out from October 2020 through January 2021. Work was completed concurrently with five other sheets in SE Norton Sound, and done in accordance with the Hydrographic Survey Project Instructions (April 2020) and the NOS Hydrographic Surveys Specifications and Deliverables (HSSD), March 2019 edition.63.8546275160.96445222263.9323958333161.326843889All waters in survey areaComplete 8840 LNM. Transit mileage, system calibration mileage and data which do not meet HSSD specifications shall not count towards the completion of the LNM requirement. Notify the COR/Project Manager upon nearing completion of LNM requirement. The final survey area shall be squared off and ensure the full investigation of any features within the surveyed extent.All waters in sheets 4 - 7320 m Set Line Spacing (Reference HSSD Section 5.2.2.4 Option A). Run lines perpendicular to shore. All significant shoals or features found in waters less than 20 m deep shall be developed to complete coverage standards. The requirement to verify or disprove all charted depths falling between sounding lines and shallower than adjacent surveyed soundings is waived.Coverage requirements were met. The following notes are provided for additional clarification. Approximately 9,242 LNM were acquired project-wide, exceeding the requirement by 402 LNM. The excess of about 4% was collected to compensate for inefficiencies incidental to the execution of data collection such as crossline mileage that exceeded requirements, data acquired on run-ins or run-outs, and excess overlap, if any. LNM quantities do not include transit or calibration data, or mileage that does not meet HSSD specifications. Splits on charted soundings were not required. No significant shoals were found requiring development to Complete MBES standards.ContractorApproach to UnalakleetnaUnited States40000Alaska5H133742020-09-092020-09-10Navigable Areameters2020Thomas MorinoAny 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 3N, MLLW. All references to other horizontal or vertical datums in this report are applicable to the processed hydrographic data provided by the field unit.Pacific Hydrographic BranchUTC2020-04-14Multibeam Echo SounderMultibeam Echo Sounder BackscatterNorton SoundTerrasondNorton Sound, AKOPR-R385-KR-20