OPR-O346-FA-17Yakutat BayYakutat BayNOAA Ship FAIRWEATHERH130702Monti BayAlaskaUnited States400002017CDR Mark Van Waes, NOAANavigable Area2017-08-102017-09-152017-10-29Multibeam Echo SounderMultibeam Echo Sounder BackscattermetersUniversal Transverse Mercator (UTM)UTCPacific Hydrographic BranchThe purpose of this survey is to provide contemporary surveys to update National Ocean Service (NOS) nautical charts. All separates are filed with the hydrographic data. Any revisions to the Descriptive Report (DR) generated during office processing are shown in bold red italic text. The processing branch maintains the DR as a field unit product, therefore, all information and recommendations within the body of the DR are considered preliminary unless otherwise noted. The final disposition of surveyed features is represented in the OCS nautical chart update products. All pertinent records for this survey, including the DR, are archived at the National Centers for Environmental Information (NCEI) and can be retrieved via http://www.ncei.noaa.gov/. NOAAThe survey area is located in Yakutat Bay within the sub-locality of Monti Bay.59.6002074444139.960185559.5090099722139.728802917H13070 sheet limits (in blue) overlaid onto Chart 16761 and Chart 16760SupportFiles\H13070_Sheet_Limits.pngData were acquired to the survey limits in accordance with the requirements in the Project Instructions and the April 2017 NOS Hydrographic Surveys Specifications and Deliverables (HSSD), as shown in Figure 1. In all areas where the 4 meter depth contour or the sheet limits were not met, the Navigable Area Limit Line (NALL) was defined as the inshore limit of bathymetry due to risks of maneuvering the vessel. In the area around Ocean Cape, the NALL was defined by the presence of large swells and breaking waves, rendering the area unsafe to navigate with the launches (Figure 2).NALL defined by waves and breakersSupportFiles\H13070_NALL_wavesbreakers.pngYakutat Bay has seen a rapid increase in the number and size of visiting vessels in recent years. Much of this can be attributed to ecotourism amid the area's glaciers, wilderness, and Tongass National Forest. Hubbard Glacier, one of four glaciers which terminate in Disenchantment Bay at the north end of Yakutat Bay, is the largest tidewater glacier in North America. Unlike most other glaciers in Alaska, which are receding, Hubbard’s terminus is predicted to continue advancing during the next several years. As a result of this advancement, and the glacier’s dramatic calving displays, the glacier is likely to draw more vessel traffic for the foreseeable future to an area of shifting moraines and lag deposits. Under keel clearance is a risk for the larger cruise ships, which can draft up to 8 meters. Although the bay itself is deep, reaching over 140 fathoms, all traffic has to pass over a glacial terminal moraine, which forms a sill at the mouth of the bay. Near the center of this entrance is a shoal reported to be 6.4 meters (3 ½ fathoms) deep in an area where surveys have not been updated in over 35 years. Royal Caribbean has reported significant chart discrepancies off of the primary route. The local community of Yakutat is dependent on barge access for delivery of its supplies and groceries. Their economy is largely timber, subsistence hunting, fishing, and tourism. Modern surveys will increase the safety of all of these activities. The Yakutat Bay survey will provide modern bathymetry to update the 1978 vintage survey data. This will update Coast Survey charts and products, improving maritime safety and protecting the local economy. The entire survey is adequate to supersede previous data.Data acquired in H13070 meet multibeam echo sounder (MBES) coverage requirements for complete coverage and object detection 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). Additional compliance statistics can be found in the Standards and Compliance Review located in Appendix II of this report. All waters in survey areaComplete CoverageExtents of 1:10000 US5AK3XM within H13070 Monti BayObject Detection CoverageTo ensure that all data meet the requirements listed above and in the HSSD, two surfaces were created for this project. Figure 3 provides an overview of the surface generated for the entirety of the project to meet complete coverage specifications. Figure 4 provides an overview of the surface generated within the extents of ENC US5AK3XM to meet object detection specifications.H13070 survey coverage overlaid onto Chart 16761 and Chart 16760SupportFiles\H13070_Coverage.pngH13070 surface generated for the Monti Bay insetSupportFiles\H13070_Object_Detection_Overview.png2806064.100000011.26028070201.16000000028080117.50000004.4800382.830000015.7504.111200014.42017-09-152017-09-192017-09-202017-09-262017-09-272017-09-282017-09-292017-09-302017-10-012017-10-022017-10-122017-10-182017-10-29Refer 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.28068.61.128078.61.128088.61.1Kongsberg MaritimeEM 2040MBESSea-Bird ScientificSBE 19plus V2Conductivity, Temperature, and Depth SensorTeledyne RESONSVP 71Sound Speed SystemApplanixPOS MV v5Positioning and Attitude SystemThe equipment was installed on the survey platforms as follows: all launches utilize Kongsberg EM 2040 MBES, Teledyne RESON SVP71 surface sound speed sensors, and Sea-Bird Scientific 19plus CTD casts.Crosslines were collected, processed and compared in accordance with Section 5.2.4.3 of the HSSD. To evaluate crosslines, a surface using strictly mainscheme lines, and a surface using strictly crosslines were created. From these two surfaces, a difference surface (mainscheme - crosslines = difference surface) was generated (Figure 5), and is submitted in the Separates II Digital Data folder. Statistics show the mean difference between the depths derived from mainscheme data and crossline data was 0.00 and 95% of nodes falling within +/- 0.24 meters (Figure 6). For the respective depths, the difference surface was compared to the allowable NOAA uncertainty standards. In total, 99.93% of the depth differences between H13070 mainscheme and crossline data were within allowable NOAA uncertainties.Overview of H13070 crosslinesSupportFiles\H13070_XL_Diff.pngH13070 crossline and mainscheme difference statisticsSupportFiles\H13070 Crossline Difference_depth_delta.png0.00.0TCARI0.00.13ERS via PMVD280X2N/A0.5In addition to the usual a priori estimates of uncertainty provided via device models for vessel motion, ERZT, and Poor Man's VDatum (PMVD), real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H13070. Real-time uncertainties were provided via EM 2040 MBES data, Applanix Delayed Heave RMS, and TCARI tides. 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.H13070 junctions with two adjacent survey from this project, H13069 and H13073, as shown in Figure 7. Data overlap between H13070 and each adjacent survey was achieved. These areas of overlap between surveys were reviewed with CARIS HIPS and SIPS by surface differencing to assess surface agreement. The junctions with H13070 are generally within the NOAA allowable uncertainty in the area of overlap. For the junctions with H13070, a negative difference indicates H13070 was shoaler, and a positive difference indicates H13070 was deeper. Overview of H13070 junction surveysSupportFiles\H13070_Junction_Overview.pngH13073200002017NOAA Ship FAIRWEATHERNWSurface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the surface generated from H13070 data and the surface generated from H13073 data. The statistical analysis of the difference surface shows a mean of -0.04 meters with 95% of all nodes having a maximum deviation of +/- 0.44 meters, as seen in Figure 9. It was found that 99.86% of nodes are within the NOAA allowable uncertainty. The largest differences are located on the northern side of the junction, as seen in Figure 8.Difference surface between H13070 (blue) and junctioning survey H13073 (pink)SupportFiles\H13070_Junction_H13073_Diff.pngDifference surface statistics between H13070 and H13073SupportFiles\Junction Difference between H13070 and H13073_depth_delta.pngH13069200002017NOAA Ship FAIRWEATHERWSurface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the surface generated from H13070 data and the surface generated from H13069 data (Figure 10). The statistical analysis of the difference surface shows a mean of 0.05 meters with 95% of all nodes having a maximum deviation of +/- 0.26 meters, as seen in Figure 11. It was found that 99.91% of nodes are within the NOAA allowable uncertainty. Difference surface between H13070 (blue) and junctioning survey H13069 (brown)SupportFiles\H13070_Junction_H13069_Diff.pngDifference surface statistics between H13070 and H13069SupportFiles\Junction_Diff_13070_13069_depth_delta.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.Casts were conducted at a minimum of one every four hours during launch acquisition. Casts were conducted more frequently in areas where the influx of freshwater had an effect on the speed of sound in the water column and when there was a change in surface sound speed greater than two meters per second. All sound speed methods were used as detailed in the DAPR.All equipment and survey methods were used as detailed in the DAPR.HolidaysH13070 data were reviewed in CARIS HIPS and SIPS for holidays in accordance with Section 5.2.2.3 of the HSSD. The Pydro QC Tools Holiday Finder tool, which automatically scans surfaces for holidays as defined in the HSSD, was run independently for the complete coverage surface generated from the entirety of the data acquired within H13070, as well as for the object detection surface generated from the data acquired within the Monti Bay inset, adjusting the holiday thresholds accordingly. Two holidays which meet the definition described in HTD 2017-2 for complete coverage were identified via the Holiday Finder tool in the areas where data were acquired to complete coverage standards. Holiday "1" is a result of shadowing from an object on the seafloor, while holiday "2" is a result of data being rejected upon conversion in CARIS HIPS and SIPS due to flags from realtime analysis by the sonar. The data over holiday "2" does capture the least depth, while the coverage surrounding Holiday "1" does not does not confidently capture the least depth. Two holidays which meet the definition described in HTD 2017-2 for object detection were identified via the Holiday Finder tool in the inset where data were acquired to object detection standards. Both holidays are a result of sparse outerbeam data while defining the NALL, and were in areas deemed unsafe to develop further as shown in Figure 14.H13070 complete coverage holiday overviewSupportFiles\H13070_Complete_Coverage_Holidays.pngH13070 complete coverage holidays shown in Caris subset editorSupportFiles\H13070_Complete_Coverage_Holidays_Closeup.pngH13070 object detection holiday overviewSupportFiles\H13070_Object_Detection_Holidays.pngNOAA Allowable UncertaintyThe complete coverage surface and the object detection surface generated from H13070 data were independently analyzed via the Pydro QC Tools Grid QA feature to determine compliance with specifications. Overall, more than 99% of the nodes in each surface meet NOAA allowable uncertainty specifications. See the Standards and Compliance Review located in Appendix II for a graphical representation of uncertainty compliance.DensityThe complete coverage surface and the object detection surface generated from H13070 data were independently analyzed via the Pydro QC Tools Grid QA feature to determine compliance with specifications. Overall, more than 99% of the nodes in the complete coverage surface meet density specifications. For the object detection surface, 96% of the nodes meet density specifications. See the Standards and Compliance Review located in Appendix II for graphical representations of density compliance for each surface.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 .all file for the Kongsberg systems. All backscatter data were processed by the field unit via Fledermaus FMGT 7.7.4. All processed mosaics and .gsf files have been submitted to the Pacific Hydrographic Branch. See Figure 15 for a complete mosaic.H13070 backscatter mosaicSupportFiles\H13070_BackscatterMosaic.pngTeledyne CARISHIPS and SIPS10.3.3QPSFledermaus FMGT7.7.4NOAA Profile V 5.6H13070_MB_VR_MLLWCARIS VR Surface (CUBE)Variable Resolution0109.8NOAA_VRComplete MBESH13070_MB_VR_MLLW_FinalCARIS VR Surface (CUBE)Variable Resolution0109.8NOAA_VRComplete MBESH13070_MB_VR_ObjectDetection_MLLWCARIS VR Surface (CUBE)Variable Resolution057.2NOAA_VRObject DetectionH13070_MB_VR_ObjectDetection_MLLW_FinalCARIS VR Surface (CUBE)Variable Resolution057.2NOAA_VRObject DetectionThe NOAA CUBE parameters defined in the HSSD were used for the generation of all CUBE surfaces for survey H13070. 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 v5, part of the QC Tools package within Pydro, 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 steep slopes and dynamic nature of the seafloor.Data LogsData acquisition and processing notes are included in the acquisition and processing logs, and additional processing such as final tide and sound speed application are noted in the H13070 Data Log spreadsheet. All data logs are submitted digitally in the Separates I folder.Per section 5.1.2.3 of the Field Procedures Manual (2014 ed), no Horizontal and Vertical Control Report has been generated for H13070.Mean Lower Low WaterYakutat, AK9453220TCARI9453220.tidFinal ApprovedO346FA2017.tcFinal2017-11-012017-11-21Initial reduction of acquired data to MLLW was accomplished via traditional tidal means using the Tidal Constituent And Residual Interpolation (TCARI) grid provided by HSD-OPS. Following the successful application of SBETs and computation of an Ellipsoidally Referenced Zone Tide (ERZT) separation model, ERS methods were used for reducing data to MLLW. After final tides were received, the final TCARI grids were applied to the data and used for reducing features to MLLW.ERS via Poor Mans VDATUMO346FA2017_PMVD_EPSG6332_NAD83_MLLW_Debiased.csarERS methods were used as the final means of reducing H13070 to MLLW for submission. Data were initially reduced via traditional tidal means until an ERZT separation model could be calculated. This empirically derived model was then checked for consistency and compared to the Poor Man's VDatum (PMVD) separation model provided with the Project Instructions. The PMVD separation model was then vertically shifted such that the average difference between these two separation models is zero. This vertical shift de-biases the PMVD separation model, correcting for local offsets that cannot be effectively modeled by the PMVD.North American Datum of 1983 (NAD83)UTM Zone 7 NorthVessel kinematic data were post-processed using Applanix POSPac processing software and RTX 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. For further details regarding the processing and quality control checks performed, see the H13070 POSPac Processing Logs spreadsheet located in the Separates folder. Horizontal Control IssueDuring real-time acquisition, launches 2806, 2807, and 2808 received correctors from the Wide Area Augmentation System (WAS) for increased accuracies similar to USCG DIPS stations. WAS and S Bets were the sole methods of positioning for H13070 as no DIPS stations were available for real-time horizontal control.A comparison was performed between survey H13070 and ENCs US4AK3XM and US5AK3XM, using CARIS HIPS and SIPS sounding and contour layers derived from the surface generated from H13070 data. The contours and soundings were overlaid on the charts to assess differences between the surveyed soundings and charted depths. An eight meter grid was generated from each ENC by extracting all soundings from the chart and creating an interpolated TIN surface which could be differenced with the surface generated from H13070 data. All H13070 data should supersede charted data. In general, surveyed soundings agree with the majority of charted depths. A full discussion of the comparisons follows below.US4AK3XM8000052018-02-132018-02-13falseSoundings from H13070 are in general agreement with charted depths on chart ENC US4AK3XM, with most depths agreeing to 1-4 fathoms. The largest differences are seen in the entrance to Monti Bay, where the charted contours differ so greatly that they were submitted as a DTON (see section D.1.5 and Appendix II of this report for more detailed discussions).Difference surface between H13070 and interpolated TIN surface from US4AK3XMSupportFiles\H13070_Difference_US4AK3XM.pngDifference surface statistics between H13070 and interpolated TIN surface from US4AK3XMSupportFiles\H13070_US4AK3XM_difference statistics.pngOverview of H13070 contours overlaid onto ENC US4AK3XM.SupportFiles\H13070_CC_ContourComparison_Overview.pngClose up of Monti Bay where significant differences exist between H13070 contours and ENC US4AK3XM contours.SupportFiles\H13070_CC_ContourComparison.pngUS5AK3XM1000032016-11-212016-11-21falseSoundings from H13070 are in general agreement with charted depths on ENC US5AK3XM, with most depths agreeing to 1-2 fathoms. Difference surface between H13070 and interpolated TIN surface from US5AK3XMSupportFiles\H13070_Difference_US5AK3XM.pngDifference surface statistics between H13070 and interpolated TIN surface from US5AK3XMSupportFiles\H13070_OD_diff_TINsur_US5AK3XM_Diff.pngOverview of H13070 contours overlaid onto ENC US5AK3XM.SupportFiles\H13070_OD_ContourComparison_Overview.pngNo Maritime Boundary Points were assigned for this survey.H13070 data covers a four fathom shoal that was reported in 2012. The surveyed area did not show any depths which support this reported sounding, nor are their any significant features in the surrounding area. The hydrographer recommends replacing the reported sounding with charted depths.Reported sounding in H13070 (surveyed soundings in red)SupportFiles\H13070_ReportedSounding_ChartedFeature.pngNo uncharted features exist for this survey.A significant discrepancy between the charted contours and surveyed depths was observed during acquisition, prompting one Danger to Navigation Report to be submitted on 11/7/2017 (Figure 24). Surveyed data revealed the 3 fathom contour lies outside of the charted 10 fathom contour line. Additionally, in this area the intertidal zone extends as much as 450 meters from the charted shoreline. The Danger to Navigation Report is included in Appendix II of this report. While surveying the area South of Pt. Mulgrove, a shoal area was defined by the 4 meter contour (Figure 25). During shoreline investigation, no features were observed in this area above the surface, and a least depth was unable to safely be obtained within the ensuing gap in coverage. Caution is advised to mariners transiting the area.Overview of DTON found in entrance to Monti BaySupportFiles\H13070_DTON_Overview.pngShoal area south of Pt. Mulgrove with gap in survey coverageSupportFiles\H13070_GapinCoverage.pngThe field-submitted DTON will be applied to the chart once the survey has been reviewed and submitted to MCD.No channels exist for this survey. There are no precautionary areas, safety fairways, traffic separation schemes, pilot boarding areas, or channel and range lines within the survey limits. The Rurik Harbor designated anchorage northeast of Port Mulgrave was relocated to reflect the description in the Coast Pilot and conditions observed during field operations.Twelve bottom samples were acquired in accordance with the Project Instructions for survey H13070 and entered in the H13070 Final Feature File. Additional bottom samples were unable to be collected due to time constraints. See Figure 26 for a graphical overview of the location of the bottom samples. H13070 bottom sample locationsSupportFiles\H13070_BottomSamples.pngAll features within the survey limits and the NALL were addressed and attributed in the H13070 Final Feature File. All features inshore of the NALL were attributed in the Final Feature File with the description of "Not Addressed" and remarks of "Retain as charted, not investigated due to being inshore of NALL" as per HSSD Section 7.3.1. Annotations, information, and diagrams collected on DP forms and boat sheets during field operations are scanned and included in the Separates I Detached Positions folder. No prior survey comparisons exist for this survey.Buoys numbered 1, 2, and 4 are located within H13070 and were observed to be on station and serving their intended purposes.No overhead features exist for this survey.No submarine features exist for this survey.No platforms exist for this survey.Ferry routes and/or terminals exist for this survey, but were not investigated.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 herein.CDR Mark Van WaesChief of Party2018-04-13LT Damian MandaField Operations Officer2018-04-13HCST Samuel CandioChief Survey Technician2018-04-13LTJG Jeffrey DouglasSheet Manager2018-04-13