OPR-Q328-FA-16North Coast of Unalaska IslandUnalaska Island, AKNOAA Ship FAIRWEATHERH129393Vicinity of Eider Point and Wide BayAlaskaUnited States200002016CDR Mark Van Waes, NOAANavigable Area2016-07-232016-08-122016-08-20Multibeam Echo SounderMultibeam Echo Sounder BackscattermetersUniversal Transverse Mercator (UTM)UTCPacific Hydrographic BranchNOAAThe survey area is located on the North Coast of Unalaska Island, AK, within the sub-locality near Eider Point and Wide Bay.53.9808557778166.64539419453.92692625166.516400917H12939 sheet limits (in red) overlaid onto Chart 16528SupportFiles\new_survey_limits.jpgData were acquired to the survey limits in accordance with the requirements in the Project Instructions and the 2016 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 by the inshore limit of safe navigation due to the risks of maneuvering the survey vessel in close proximity to the steep and rocky shoreline, particularly along the edges of the ledge that extends from Eider Point as shown in Figure 2. H12939 Area south of Eider Point where the NALL was defined by coverage to the extent of ledgeSupportFiles\nearshore_near_eider.jpgThe purpose of this project is to provide contemporary surveys to update National Ocean Service nautical charting products in a high commercial traffic area. This project covers 10.06 SNM and is a component of a survey that is a direct response to the USCG’s request for a hydrographic survey after the July 2015 grounding of a polar ice class vessel, in addition to addressing local pilot requests for modern hydrography to support an increasing amount of vessel traffic in the area.The entire survey is adequate to supersede previous data.Data acquired in H12939 meets multibeam echo sounder (MBES) coverage requirements for complete coverage, as required by the 2016 Hydrographic Surveys Specifications and Deliverables (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 in Appendix II of this report. Inshore limit to 8 meters water depthEither complete coverage or multibeam set line spacing at 25m, as identified in the PRF by CTNARE areas. Refer to HSSD Sections 5.2.2.3, 5.2.2.4, and 5.2.2.1Greater than 8 meters water depthComplete coverage. Refer to HSSD Section 5.2.2.3.The entirety of H12939 was completed with MBES coverage with backscatter meeting the above listed requirements from the HSSD 2016. See Figure 3 for the coverage extent. H12939 Coverage graphic SupportFiles\new_coverage_graphic.jpgFA 2805051.50000004.570FA 2806022.57000003.170FA 2808035.2400000000109.278000007.75800404010.062016-08-122016-08-152016-08-162016-08-182016-08-20Refer 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.28058.641.1228068.641.1228088.641.12SeaBird19plusConductivity, Temperature, and Depth SensorRESONSVP71Sound Speed SystemApplanixPOS/MV V4Positioning and Attitude SystemRESON7125MBESCrosslines were collected, processed, and compared in accordance with Section 5.3.4.3. To evaluate crosslines, a 16-meter CUBE surface using strictly mainscheme lines, and a 16-meter CUBE surface using strictly crosslines were created. From these two surfaces, a difference surface (mainscheme-cross line= difference surface) was generated at a 16-meter resolution (Figure 4), and is submitted in the Separates II Digital Data folder. Statistics show the mean difference was -0.04 meters with 95% of nodes falling within 1.08 meters (Figure 5). For the respective depths, the difference surface was compared to the allowable NOAA accuracy standards (Figure 6). In total, 99.45% of the depth differences between H12939 mainscheme and crossline data are within allowable NOAA uncertainties (Figure 6, 7). H12939 Mainscheme and crossline difference surfaceSupportFiles\Crossline_difference_new.pngH12939 Mainscheme and crossline difference statisticsSupportFiles\H12939_crossline_new.pngH12939 Crossline difference VS. Allowable NOAA UncertaintySupportFiles\H12939_XL_NOAAness.pngH12939 Crossline difference VS. Allowable NOAA Uncertainty statisticsSupportFiles\Crossline_NOAAness_stat_table.png00.06Discrete Zoning00.04ERS via PMVD28052N/A0.528062N/A0.528082N/A0.5In addition to the usual a priori estimates of uncertainty provided via device models for vessel motion, discrete zoned tides, PMVD, and real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H12939. Real-time uncertainties were provided via Reson 7125 MBES data and Applanix Delayed Heave RMS. Following post-processing of vessel motion, real-time uncertainties of vessel roll, pitch, gyro, and navigation are applied in CARIS HIPS and SIPS via a Smoothed Best Estimate of Trajectory (SBET) RMS file generated in Applanix POSPac. H12939 junctions with three adjacent surveys from this project, H12937, H12938, H12940, and one survey from a prior project, F00601, as shown in Figure 8. Data overlap between H12939 and each adjacent survey was achieved. The areas of overlap between surveys were reviewed with CARIS HIPS and SIPS through surface differencing the 8 meter combined surface with F00601, H12937, and H12940, and with the the 16 meter combined surface for H12938 to assess surface agreement. The multibeam data was also examined in CARIS Subset Editor for consistency and agreement. All junctions with H12939 meet the NOAA Allowable Uncertainty in their areas of overlap. For all junctions with H12939, a positive difference indicates H12939 was deeper, and a negative difference indicates H12939 was shoaler. Junctions with H12940, H12938, H12937, and F00601SupportFiles\H12939_junctions.pngF0060150002011NOAA Ship FAIRWEATHERN Surface differencing in CARIS HIPS and SIPS was used to asses junction agreement between H12939 and survey F00601 that was conducted in July 2011 by the NOAA Ship Fairweather (Figure 9). The statistical analysis of the difference surface from H12939 and F00601 shows a mean difference of 0.18 meters with 95% of all nodes falling within a deviation of +/- 0.59 m. A detailed graphical overview can be seen in Figure 10. A comparison surface was created between the difference surface and the allowable NOAA uncertainty (Figure 11). The comparison showed that 98.47% of the nodes are within NOAA Allowable Uncertainty (Figure 12). Difference surface between H12939 and F00601SupportFiles\H12939_F00601_surface junction.pngDifference statistics between H12939 and F00601SupportFiles\H12939_F00601_junction.pngJunction H12939/F00601 VS. Allowable NOAA Uncertainty surfaceSupportFiles\H12939_F00601_NOAAness.pngStatistics for junction H12939/F00601 VS. NOAA Allowable UncertaintySupportFiles\H12939_F00601_NOAAness_stats_new.pngDuring branch review discrepancies were found between the reported junction analysis and the junction analysis performed by the branch. The following figure captures the analysis performed at the branch. With that being said, H12939 agrees very well with its junctions.Junction analysis between H12939 and F00601file:///M:/OPRQ328FA16/Surveys/H12939/Compilation/QC/SAR/Images/H12939-F00601.pngH1293750002016NOAA Ship FAIRWEATHERSE Surface differencing in CARIS HIPS and SIPS was used to asses junction agreement between the 8 meter combined surfaces from H12939 and the 8 meter combined surface from survey H12937 (Figure 13). The statistical analysis of the difference surface shows a mean of 0.04 meters with 95% of all nodes having a maximum deviation of +/- 0.68 m. A detailed graphical overview can be seen in Figure 14. A comparison surface was created between the difference surface and the allowable NOAA uncertainty (Figures 15). It was found that 98.84% of the nodes are within allowable NOAA uncertainty (Figure 16). Difference surface between H12939 and H12937SupportFiles\H12939_H12937_new_difference.pngDifference statistics between H12939 and H12937SupportFiles\H12939_H12937_junction.pngJunction H12939/H12937 VS. NOAA Allowable UncertaintySupportFiles\H12939_H12937_NOAAness_new.pngStatistics for Junction H12939/H12937 VS. NOAA Allowable UncertaintySupportFiles\H12939_H12937_NOAAness_stats_new.pngDuring branch review discrepancies were found between the reported junction analysis and the junction analysis performed by the branch. The following figure captures the analysis performed at the branch. With that being said, H12939 agrees very well with its junctions.Junction analysis between H12939 and H12937.file:///M:/OPRQ328FA16/Surveys/H12939/Compilation/QC/SAR/Images/H12939-H12937.pngH1293850002016NOAA Ship FAIRWEATHERS Surface differencing in CARIS HIPS and SIPS was used to asses junction agreement between the 16 meter combined surfaces from H12939 and the 16 meter combined surface from survey H12938 (Figure 17). The statistical analysis of the difference surface shows a mean of -0.06 meters with 95% of all nodes having a maximum deviation of +/- 0.87 m. A detailed graphical overview of the difference statistics can be seen in Figure 18. A comparison surface was created between the difference surface and the allowable NOAA uncertainty (Figure 19). It was found that 99.92% of nodes fall within allowable NOAA uncertainty (Figure 20).Difference surface between H12939 and H12938SupportFiles\H12939_H12938_junction_new.pngDifference statistics between H12939 and H12938SupportFiles\H12939_H12938_junction_statistics.pngJunction H12939/H12938 VS. NOAA Allowable UncertaintySupportFiles\H12939_H12938_NOAAness_new.pngStatistics for junction H12939/H12938 VS. NOAA Allowable UncertaintySupportFiles\H12939_H12938_NOAAness_statistics.pngDuring branch review discrepancies were found between the reported junction analysis and the junction analysis performed by the branch. The following figure captures the analysis performed at the branch. With that being said, H12939 agrees very well with its junctions.Junction analysis between H12939 and H12938.file:///M:/OPRQ328FA16/Surveys/H12939/Compilation/QC/SAR/Images/H12939-H12938.pngH12940200002016NOAA Ship FAIRWEATHERESurface differencing in CARIS HIPS and SIPS was used to asses junction agreement between the 16 meter combined surfaces from H12939 and the 16 meter combined surface from survey H12940 (Figure 21). The statistical analysis of the difference surface shows a mean of -0.02 meters with 95% of all nodes having a maximum deviation of +/- 0.53 m. A detailed graphical overview can be seen in Figure 22. A comparison surface was created between the difference surface and the allowable NOAA uncertainty (Figure 23). It was found that 99.95% of nodes fall within allowable NOAA uncertainty (Figure 24). Difference surface between H12939 and H12940SupportFiles\H12939_H12940_new_junction.pngDifference statistics between H12939 and H12940SupportFiles\H12939_H12940_junction_newest.pngJunction H12939/H12940 VS. NOAA Allowable UncertaintySupportFiles\H12939_H12940_NOAAness_new.pngStatistics for junction H12939/H12940 VS. NOAA Allowable UncertaintySupportFiles\H12939_H12940_NOAAness_statistics.pngDuring branch review discrepancies were found between the reported junction analysis and the junction analysis performed by the branch. The following figure captures the analysis performed at the branch. With that being said, H12939 agrees very well with its junctions.Junction analysis between H12939 and H12940.file:///M:/OPRQ328FA16/Surveys/H12939/Compilation/QC/SAR/Images/H12939-H12940.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.Sea StateThere were some survey days during acquisition for survey H12939 with high sea state that caused excessive pitch and roll for the survey launches. On DN 225 Launch 2805 experienced excessive blow outs while acquiring cross lines. Vessel motion artifacts around the edges of crosslines are visible on the surface in Subset Editor of CARIS HIPS and SIPS. Figures 25 and 26 show an example of such an area below. Data remains within allowable uncertainties, however, and is adequate to supersede previous data. Example of blow outs around edges of crosslines (Vertical exaggeration x12)SupportFiles\Crossline blowouts.jpgH12939 Data with evident blowouts on DN 225SupportFiles\DN 225 blow out.pngCasts were conducted at a minimum of once every 4 hours during launch acquisition with a SeaBird 19Plus V2 profiler. Casts were conducted more often 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 equipment and survey methods were used as detailed in the DAPR.Holiday Assessment H12939 data were reviewed in CARIS HIPS and SIPS for holidays in accordance with section 5.2.2.3 of the HSSD. All finalized surfaces were scanned for holidays via Pydro QC Tools Holiday Finder tool in conjunction with a visual inspection by the hydrographer. One holiday was found northeast of Eider Point in a particularly rocky area (Figure 27). This dynamic seafloor caused an acoustic shadow due to lack of coverage on the "back" side of the rock due to poor geometry from the sonar head (Figure 28). The area was investigated in CARIS subset editor to verify that least depths were found. Other apparent holidays were identified in the finalized surfaces by Holiday Finder and then examined and determined to be in areas where adjoining surfaces covered the gap (e.g. a holiday in a shoal area of the 2 meter finalized surfaces was covered by the depth bands in the 1 meter finalized surface), as shown in Figure 29. H12939 Holiday near Eider PointSupportFiles\Holiday_North_Eider_Point.pngHoliday near Eider Point with least depth shown in 3D Subset EditorSupportFiles\holiday least depth.pngArea where adjoining finalized 1 meter surface (in grey) covers flagged holiday in the 2 meter finalized surface (in pink)SupportFiles\Holiday_surface_edges.pngNOAA Allowable UncertaintyTo verify that all data meets the accuracy specifications as stated in HSSD Section 5.1.3, a child layer titled "NOAA_Allowable_1" was created for each of the 1-meter, 2-meter, 4-meter, and 8-meter (72-100) and "NOAA_Allowable_2" for the 8-meter (100-160m) and 16-m finalized surfaces using the equations stated in section C.2.1 of the DAPR. These surfaces were analyzed using Pydro QC Tools Grid QA feature to determine what percentage of each surface meets specifications. Figure 30 shows an overview of the NOAA Allowable Uncertainty layers for all surfaces. Figure 31 shows the corresponding statistics for each individual surface. Overall, 99.71% of the nodes with all surfaces meets or exceeds NOAA Allowable Uncertainty specifications for H12939. For individual graphs per surface of density requirements, see the Standards and Compliance Review located in Appendix II. H12939 NOAA Allowable Uncertainty overviewSupportFiles\H12939_NOAA_Allowable_Uncertainty.pngH12939 NOAA Allowable Uncertainty statisticsSupportFiles\NOAA_Allowable_Uncertainty.pngDensity ComplianceFinalized surfaces were analyzed using Pydro QC Tools Grid QA feature and the results are shown in Figure 32 below. Density requirements for H12939 were achieved with at least 99.33% of finalized surface nodes containing five or more soundings as required by HSSD Section 5.2.2.3 (Figure 33). For individual graphs (per surface) of density requirements, see the Standards and Compliance Review located in Appendix II. H12939 Density Compliance overviewSupportFiles\H12939_Density.pngH12939 Density statisticsSupportFiles\H12939_Density_new.pngAll data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.Raw Backscatter was logged as a 7k file for Reson 7125 data. Backscatter was processed in Fledermaus FMGT to choose bottom sample locations that provided a more diverse sample of bottom type. The corresponding mosaics, tiffs, projects, and GSF files have been sent to the Processing Branch. Figure 34 shows an overview of the mosaic created from H12939 survey data.H12939 Backscatter mosaicSupportFiles\Backscatter.jpgTeledyne CarisHIPS and SIPS9.1QPSFledermaus FMGT7.5.3NOAA Extended Attribute Files version 5.4.H12939_MB_1m_MLLWCUBE1NOAA_1mComplete MBESH12939_MB_2m_MLLWCUBE2NOAA_2mComplete MBESH12939_MB_4m_MLLWCUBE4NOAA_4mComplete MBESH12939_MB_8m_MLLWCUBE8NOAA_8mComplete MBESH12939_MB_16m_MLLWCUBE16NOAA_16mComplete MBESH12939_MB_1m_MLLW_FinalCUBE1020NOAA_1mComplete MBESH12939_MB_2m_MLLW_FinalCUBE21840NOAA_2mComplete MBESH12939_MB_4m_MLLW_FinalCUBE43680NOAA_4mComplete MBESH12939_MB_8m_MLLW_FinalCUBE872160NOAA_8mComplete MBESH12939_MB_16m_MLLW_FinalCUBE16144320NOAA_16mComplete MBESThe NOAA CUBE parameters mandated in the HSSD March 2016 were used to create all of the CUBE surfaces in Survey H12939. 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 be shoaler or deeper than 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 v3, part of the QC Tools package within Pydro, was used to assist the search for spurious soundings following gross cleaning. Flier Finder was run multiple times for each surface, reducing the flier height value for each consecutive run. This allowed Flier Finder to accurately and quickly identify gross fliers, but as the flier height was reduced the effectiveness of the tool diminished. With smaller heights, Flier Finder began to incorrectly flag dynamic aspects of the seafloor such as steep drop offs and rocky areas as fliers resulting in some false positives. At this point, the hydrographer ceased using the tool and returned to manual cleaning for these dynamic regions of seafloor.Data LogsData acquisition and processing notes are included in the acquisition and processing logs, and additional processing such as final tides and sound speed application is noted in the H12939 Data Log spreadsheet. All data logs are submitted digitally in the Separates I folder.No control stations were installed by the field party, and as such, no Horizontal and Vertical Control Report (HVCR) is submitted with this report. All relevant discussion regarding horizontal and vertical control may be found in the discussion below. Mean Lower Low WaterUnalaska, AK9462620Discrete Zoning9462620.tidFinal ApprovedQ328FA2016CORP.zdfFinal2016-08-262016-09-08Initial reduction of acquired data to the MLLW was accomplished via traditional tidal means using the discrete zoning 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. Preliminary zoning was accepted as the final zoning for project OPR-Q328-FA-16.ERS via Poor Mans VDATUMQ328FA2016CORP_PMVDERZT_UTM-WGS84-8N_WGS84-MLLW_100m.csarERS methods were used as the final means of reducing H12939 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. In areas where the PMVD model did not have sufficient coverage such as near shore areas, the ERZT separation model was appended to the PMVD model creating the composite ERZT/PMVD separation model listed above and used to reduce H12939 to MLLW. For further information see the ERS Capability Memo, submitted under a separate cover.World Geodetic System of 1984 (WGS84)UTM Zone 3 NorthSingle BaseAV09Haystack_AK2004Vessel kinematic data was post-processed using Applanix POSPac processing software with Single Base positioning methods as described in the DAPR. Smooth Best Estimate of Trajectory (SBET) and associated error (RMS) data were applied to all MBES data in CARIS HIPS. For further details regarding the processing and quality control checks performed see the H12939 POSPAC Processing Logs spreadsheet located in the Separates folder. See also the OPR-Q328-FA-16 Horizontal and Vertical Control Report, submitted under separate cover. Hydrographic Technical Directive (HTD) 2016-3, which revises the horizontal datum requirement was released after the Project Instructions were issued for OPR-Q328-FA-16. A waiver to maintain WGS84 as the datum for submission was granted by the Hydrographic Survey Division Operations Branch. This correspondence has been included in Appendix II. WAASDuring real-time acquisition launches 2805, 2806, and 2807 received correctors from the Wide Area Augmentation System (WAAS) for increased accuracies similar to the USCG DGPS stations. WAAS and SBETs were the sole methods of positioning for survey H12939. No DGPS stations were available for real-time horizontal control. A comparison was performed between survey H12939 and Chart 16528 as well as US5AK6CM using CARIS HIPS and SIPS sounding and contour layers derived from the 16 meter combined surface. The contours and soundings were overlaid on the chart to assess differences between the surveyed soundings and charted depths. ENCs were compared to a 16 meter combined grid by extracting all soundings from the chart and creating an interpolated TIN surface which could be differenced from the 16 meter combined surface from H12939. All data from H12939 should supersede charted data. In general, surveyed soundings agree with the majority of charted depths however there are some areas within H12939 that have large discrepancies. A full discussion of the disagreements follows below. 16528252240000182012-092016-04-052016-04-09The charted depths and contours of Chart 16528 are identical to those found on ENC US5AK6CM. As such, all discussions regarding the comparisons between surveyed soundings and charted depths are covered under the ENC US5AK6CM discussion below. US5AK6CM40000132015-11-252015-11-25falseSoundings from H12939 are in general agreement with charted depths on ENC US5AK6CM within one to two fathoms as shown in Figure 36. The largest differences are seen around the ledge extending from Eider Point, and in the central basin, where ENC soundings are up to 10 fathoms shoaler than surveyed soundings (Figure 35). To more accurately visualize trends within these differences, a 16 meter TIN surface was interpolated from the ENC sounding layer. This surface was then differenced with a corresponding 16 meter surface from H12939 and visualized in Figure 35. In this difference surface red colors indicate H12939 was shoaler than the ENC US5AK6CM, green colors indicate agreement, and blue colors indicate H12939 was deeper than ENC US5AK6CM. Soundings from H12939 agree with charted depths on ENC US5AK6CM with a mean difference of 0.25 meters and 95% of all soundings having a maximum deviation of 12.55 meters (Figure 37). The most significant differences observed were up to 20 fathoms in the southwest corner of H12939. Large differences are seen in a few nearshore areas, particularly on the western edge of the ledge that extends south from Eider Point, that are much shoaler (up to 10 fathoms shoaler) than previously charted. The other areas where surveyed soundings are shoaler than charted are clustered along the 100 fathom contour in the north central part of the survey. Contours from H12939 are in general agreement with charted contours on ENC US5AK6CM as shown in Figure 38. The largest differences are seen in the 3 and 10 fathom contours where surveyed and charted contours differ by over 100 meters as seen in Figure 39. The Hydrographer recommends that the contours be retained as charted, and although nearshore contours appear clustered, they mark a rapidly shoaling slope that is significant for navigation. H12939 soundings in fathoms (in white) compared to ENC US5AK6CM depths in fathoms (in black)SupportFiles\deep shoal sounding.pngOverview of H12939 and US5AK6CM surface differenceSupportFiles\H12939_ENC_difference_New.pngDifference surface statistics between H12939 and interpolated TIN surface from US5AK6CMSupportFiles\H12939_ENC_US5AK6CM_Difference_16m.pngOverview of H12939 contours overlaid on US5AK6CMSupportFiles\new_contour_image.pngContour differences near Eider Point between H12939 and US5AK6CMSupportFiles\contour_discrepancies.pngNo Maritime Boundary Points were assigned for this survey. All assigned features within the NALL were addressed and are included in the H12939 Final Feature File. Assigned features inshore of the NALL were given the description of "Not Addressed" with remarks "Retain as charted, not investigated due to being inshore of NALL" in accordance with HSSD 7.3.1.Survey H12939 has 4 new features that are addressed in the H12939 Final Feature File. All 4 new features are Seabed Areas. No Danger to Navigation Reports were submitted 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 H12939. After backscatter was processed for H12939, bottom sample locations were changed from the assigned locations in the Project Instructions to more accurately reflect changes in seafloor type. All bottom samples were entered in the H12939 Final Feature File. See Figure 40 for a graphical overview of sample locations. H12939 Bottom samplesSupportFiles\H12939_bottom_samples_plain.jpgH12939 survey limits extended to the NALL (see Section A.1) and all features within these limits were addressed and attributed in H12939 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 were assigned for this survey.Aids to navigation (ATONs) exist for this survey, but were not investigated.No overhead features exist for this survey.Three abandoned cable areas run the length survey H12939 from NW to S. The cable areas are not visible in the data and no dangers were found during acquisition of survey H12939.No ferry routes or terminals exist for this survey.No platforms exist for this survey.No Significant Features 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, except as noted in the Descriptive Report. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required unless otherwise noted herein. CDR Mark Van Waes, NOAAChief of Party2016-12-01LT Bart Buesseler, NOAAField Operations Officer2016-12-01HCST Douglas BravoChief Survey Technician2016-12-01HST Hannah MarshburnSheet Manager2016-12-01Data Acquisition and Processing Report2016-10-25Coast Pilot Report2016-10-26