OPR-R320-FA-19Vicinity of Cape NewenhamAlaskaNOAA Ship FairweatherH1324143 NM Southeast of Cape NewenhamAlaskaUnited States400002019CDR Marc MoserNavigable Area2019-04-302019-06-192019-06-29Multibeam Echo SounderMultibeam Echo Sounder BackscattermetersUTCPacific 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 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.NOAAThe survey area is located 3 NM southeast of Cape Newenham, Alaska.58.610375162.31951658.497053161.966915H13241 sheet limits (in blue) overlaid onto Chart 16305SupportFiles\01_H13241_Sheet_Limits.pngData were acquired to the survey limits in accordance with the requirements in the Project Instructions and the March 2019 NOS Hydrographic Survey Specifications and Deliverables (HSSD) as shown in Figure 1.The purpose of this hydrographic survey is to update National Ocean Service nautical charting products and support commerce to the northern Bristol Bay region. Capes Newenham and Peirce, Alaska are the southwestern corner of the Togiak National Wildlife Refuge and provide habitat to numerous birds and sea mammals. Ship and barge traffic delivering industrial, consumer, and energy products to the communities of northern Bristol Bay, or continuing north to Etolin Strait must transit around these capes. Marine commerce is critical for the survival of these western Alaskan communities as they are detached from the rest of the state road system. Legacy hydrographic data in this survey area is extremely sparse and was acquired prior to the 1920s. Updating the nautical charts and accurately charting reported shoals by modern hydrographic means is critical for the future safety of regional commerce, local tanker lightering, emergency response, and the protection of the local wildlife. Survey data from this project is intended to supersede all prior survey data in the common area.The entire survey is adequate to supersede previous data.Data acquired in H13241 meet multibeam echo sounder (MBES) coverage requirements for set line spacing, as required by the HSSD. This includes crosslines (see Section B.2.1), NOAA allowable uncertainty (see Section B.2.9), and density requirements (see Section B.2.10).All waters in survey areaSet Line Spacing at 400 m (Refer to HSSD Section 5.2.2.4, Option A)The entirety of H13241 was acquired with set line spacing MBES at 400m, meeting the requirements listed above and in the HSSD. See Figure 2 for an overview of coverage.H13241 survey coverage overlaid onto Chart 16305SupportFiles\02_H13241_Coverage_Overview.pngS2200149.660000012.4300149.660000012.4308.3400033.412019-06-192019-06-202019-06-222019-06-232019-06-282019-06-29Refer to the OPR-R320-FA-19 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.S22070.44.8Kongsberg MaritimeEM 710MBESAML OceanographicMVP200Conductivity, Temperature, and Depth SensorTeledyne RESONSVP 70Sound Speed SystemApplanixPOS MV 320 v5Positioning SystemThe equipment was installed on the survey platform as follows: S220 utilizes the Kongsberg EM 710 MBES, a POS MV v5 system for positioning and attitude, SVP 70 surface sound speed sensors, and AML Oceanographic MVP 200 for conductivity, temperature, and depth (CTD) casts.Crosslines were collected, processed and compared in accordance with Section 5.2.4.2 of the HSSD. 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 (Figure 3), and is submitted in the Separates II Digital Data folder. Statistics show the mean difference between depths derived from mainscheme data and crossline data was -0.01 meters (with mainscheme being shoaler) and 95% of nodes falling within +/- 0.09 meters (Figure 4). For the respective depths, the difference surface was compared to the allowable NOAA uncertainty standards. In total, 100% of the depth differences between H13241 mainscheme and crossline data were within allowable NOAA uncertainties.Overview of H13241 crosslinesSupportFiles\03_H13241_Crosslines_Overview.pngH13241 crossline and mainscheme difference statisticsSupportFiles\04_H13241_Crossline_Difference_Stats.pngERS via ERTDM0.14S22010.5In addition to the usual a priori estimates of uncertainty provided via device models for vessel motion and ERTDM, real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H13241. Real-time uncertainties were provided via EM710 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.H13241 junctions with four adjacent surveys from this project, H13238, H13240, H13242 and H13244 as shown in Figure 5. In an effort to maximize efficiency during acquisition, data were collected on a single heading on the same day across the western junction with H13242 and the eastern junction with H13240. Since the data were collected continuously across the sheet limits by the same platform with the same SBET files and separation model applied to adjacent sheets, overlap was not achieved at these junctions. A visual analysis was performed of the data across the respective sheet limits to ensure that no biases arose in processing the data. Data overlap was achieved, however, at the junctions with H13238 and H13244. These areas of overlap between surveys were reviewed in CARIS HIPS and SIPS by surface differencing (at equal resolutions) to assess surface agreement. The multibeam data were also examined in CARIS Subset Editor for consistency and agreement. The junctions with H13238 and H13244 are within the NOAA allowable uncertainty in their areas of overlap. For the junction with H13238 and H13244, a negative difference indicates H13241 was shoaler and a positive difference indicates H13241 was deeper.Overview of H13241 junction surveysSupportFiles\05_H13241_Junction_Overview.pngH13238400002019NOAA Ship FAIRWEATHERNSurface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the surface from H13241 and the surface from H13238. The statistical analysis of the difference surface shows a mean of 0.00 meters with 95% of the nodes having a maximum deviation of +/- 0.09 meters, as seen in Figure 7. It was found that 100% of nodes are within NOAA allowable uncertainty.Difference surface between H13241 (pink) and junctioning survey H13238 (purple)SupportFiles\06_H13241_Junction_H13238.pngDifference surface statistics between H13241 and H13238 (4 meter surface)SupportFiles\07_H13241_Junction_H13238_Stats.pngH13244400002019NOAA Ship FAIRWEATHERSSurface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the surface from H13241 and the surface from H13244. The statistical analysis of the difference surface shows a mean of 0.01 meters with 95% of the nodes having a maximum deviation of +/- 0.09 meters, as seen in Figure 9. It was found that 100% of nodes are within NOAA allowable uncertainty.Difference surface between H13241 (pink) and junctioning survey H13244 (blue)SupportFiles\08_H13241_Junction_H13244.pngDifference surface statistics between H13241 and H13244 (4 meter surface)SupportFiles\09_H13241_Junction_H13244_Stats.pngSonar system quality control checks were conducted as detailed in the quality control section of the DAPR.None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.None ExistThere were no other factors that affected corrections to soundings.MVP casts on S220 were conducted at an average interval of 65 minutes, guided by observation of the surface sound speed. All sound speed methods were used as detailed in the DAPR.All equipment and survey methods were used as detailed in the DAPR.NOAA Allowable UncertaintyThe surface was analyzed using the HydrOffice QC Tools Grid QA feature to determine compliance with specifications. Overall, greater than 99.5+% of nodes within the surface meet NOAA Allowable Uncertainty specifications for H13241.H13241 Allowable uncertainty statisticsSupportFiles\10_H13241_NOAA_Allowable_Uncertainty.pngDensityThe surface was analyzed using the HydrOffice QC Tools Grid QA feature to determine compliance with specifications. Density requirements for H13241 were achieved with at least 99.5+% of surface nodes containing five or more soundings as required by HSSD Section 5.2.2.4.H13241 Data density statisticsSupportFiles\11_H13241_Density.pngAll 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 .all file for Kongsberg systems. All backscatter were processed to GSF files and a floating point mosaic was created by the field unit via Fledermaus FMGT 7.8.10. See Figure 12 for a greyscale representation of the complete mosaic.Backscatter mosaic for H13241SupportFiles\12_H13241_Backscatter_Mosaic.pngCARISHIPS and SIPS11.1.3QPSFledermaus7.8.10NOAA Profile Version 2019H13241_MB_4m_MLLW_FinalCARIS Raster Surface (CUBE)433.349.0NOAA_4mMBES TracklineH13241_MB_4m_MLLWCARIS Raster Surface (CUBE)433.349.0NOAA_4mMBES TracklineThe NOAA CUBE parameters defined in the HSSD were used for the creation of all CUBE surfaces for H13241. The surfaces have been reviewed where noisy data, or "fliers" are incorporated into the gridded solutions causing the surface to be shoaler or deeper than the true sea floor. Where these spurious soundings cause the gridded surface to vary from the reliably measured seabed by greater than the maximum allowable Total Vertical Uncertainty at that depth, the noisy data have been rejected by the hydrographer and the surface recomputed. Flier Finder, part of the QC Tools package within HydrOffice, was used to assist the search for spurious soundings following gross cleaning. Flier Finder was run iteratively until all remaining flagged fliers were deemed to be valid aspects of the surface.Data LogsData acquisition and processing notes are included in the acquisition and processing logs, and additional processing such as final separation model reduction and sound speed application are noted in the H13241 Data Log spreadsheet. All data logs are submitted digitally in the Separates I folder.Per Section 5.1.2.3 of the 2014 Field Procedures Manual, no Horizontal and Vertical Control Report has been generated for H13241.Mean Lower Low WaterERS via ERTDMR320FA2019_ERTDM_NAD83-MLLW.csarERS methods were used as the final means of reducing H13241 to MLLW for submission. North American Datum 1983Projected UTM 3RTXVessel 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 real-time acquisition, S220 received correctors from the Wide Area Augmentation System (WAAS) for increased accuracies similar to USCG DGPS stations. WAAS and SBETs were the sole methods of positioning for H13241 as no DGPS stations were available for realtime horizontal control.A comparison was performed between survey H13241 and ENC US4AK86M using CARIS HIPS and SIPS. Sounding and contour layers were overlaid on the ENC to assess differences between the surveyed soundings and charted depths. ENC's were compared to the surface by extracting all soundings from the chart and creating an interpolated TIN surface which could be differenced with the surface from H13241. All data from H13241 should supersede charted data. In general, surveyed soundings agree with the charted depths. A full discussion follows below.US4AK86M10000052017-12-272017-12-27falseSoundings from H13241 are in general agreement with charted depths on ENC US4AK86M, with most depths agreeing to 0.5 fathoms as shown in Figure 13. The largest differences are seen on the western side where the difference is 2.5 fathoms as seen in Figure 15. Contours from H13241 are in general disagreement with charted contours on ENC US4AK86M as shown in Figure 15. The charted 20 fathom contour extending throughout H13241 does not exist. Instead, the surveyed 20 fathom contour remains solely on the eastern side of H13241.Difference surface between H13241 and interpolated TIN surface from US4AK86MSupportFiles\13_H13241_ENC_Difference_Overview.pngDifference surface statistics between H13241 and interpolated TIN surface from US4AK86MSupportFiles\14_H13241_ENC_Difference_Stats.pngOverview of H13241 soundings and contours overlaid onto ENC US4AK86MSupportFiles\15_H13241_Sounding_Contour_Comparison.pngNo Maritime Boundary Points were assigned for this survey.No charted features exist for this survey.No uncharted features exist for this survey.No shoals or potentially hazardous 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.Four bottom samples were acquired for survey H13241. Due to the risk of utilizing the image grab sampler from the launches in the observed sea states while on project, the smaller, non-image recording bottom sampler was used for two samples (in red). All bottom samples were entered in the H13241 Final Feature File. See Figure 16 for a graphical overview of sample locations.H13241 bottom sample locations overlaid on backscatter mosaicSupportFiles\16_H13241_Bottom_Sample_Backscatter.pngShoreline was assigned in the Hydrographic Survey Project Instructions, however, no assigned features exist for this survey.No Aids to navigation (ATONs) exist for this survey.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 and/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 insets 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.HST Simon SwartSheet Manager2019-08-07CST Samuel CandioChief Survey Technician2019-08-07LT Stephen MoultonField Operations Officer2019-08-07CDR Marc MoserChief of Party2019-08-07