In addition to the usual a priori estimates of uncertainty provided via device models for vessel motion and VDATUM, real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey F00795. Real-time uncertainties were provided via EM 2040 and PicoMB 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. To verify that all data meets the accuracy specifications as stated in HSSD Section 5.1.3, a child layer titled NOAA_Allowed_1 was created for the 50cm surface using the equations stated in Section 5.1.3 of the HSSD. These surfaces were then analyzed using the Pydro QC Tools Grid QA feature to determine what percentage of each surface meets specifications. Figure 2 shows the statistics for the surface. Overall, 99.5% of nodes meet or exceed NOAA Allowable Uncertainty specifications for F00795. For individual graphs per surface of uncertainty requirements, see the QC Tools Folder located in Appendix II.F00795 Uncertainty Statisticsfile:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/F00795_MB_MLLW_50cm.QAv5.tvu_qc.pngRefer to the S-E937-BH2-19 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.Any 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 18N, MLLW. All references to other horizontal or vertical datums in this report are applicable to the processed hydrographic data provided by the field unit.EM 2040MBESKongsberg MaritimeEM 2040MBESHYPACKEM 2040MBES BackscatterKongsberg MaritimeLittle Cove PointMean Lower Low WaterNavigable AreaS-E937-BH2-19Pacific Hydrographic BranchProjected UTM 18Lieutenant Patrick J DebroisseNOAA R/V Bay Hydro II2019-11-11F007952019-09-192019-10-15North American Datum 1983metersChesapeake Bay10000MarylandVDatum2019-09-112019CARIS Raster Surface (CUBE)F00795_MB_50cm_MLLW.csar0.5Object DetectionNOAA_0.5m11.64.0CARIS Raster Surface (CUBE)F00795_MB_50cm_MLLW_Final.csar0.5Object DetectionNOAA_0.5m11.60.3MB Backscatter MosaicF00795_MBAB_50cm_BHII_300kHz.csar0.5Object DetectionNOAA_0.5m252018-05-14US5MD21M400002019-09-25falseOverview of F00795 soundings (orange) overlaid onto ENC US5MD21M (red).file:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/Soundings_Compare.JPGOverview of F00795 contours (orange) overlaid onto ENC US5MD21M (black).file:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/Contour%20Compare.JPGA comparison was performed between survey F00795 and ENC US5MD21M using CARIS HIPS and SIPS sounding and contour layers derived from the 0.5 meter combined surface. The contours and soundings were overlaid on the chart to assess differences between the surveyed soundings and charted depths. Soundings from F00795 (orange) are in a general agreement with charted depths on ENC US5MD21M (red), with most depths agreeing to 0.3 meters as shown in Figure 3. Contours from F00795 (red) are in a general disagreement with charted contours on ENC US5MD21M (black) as shown in Figure 4. The largest differences are seen in the 5.4m contour where surveyed contour is much further in shore than the charted contour. The surveyed 9.1m contour is about 35m further inshore than charted over most of the survey area. Data acquired in F00795 meet multibeam echo sounder (MBES) coverage requirements for object detection, as required by the HSSD. This includes crosslines, NOAA allowable uncertainty, and density requirements. Additional compliance statistics can be located in Appendix II of this report. 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.Crosslines were collected, processed, and compared in accordance with Section 5.2.4.3 of the HSSD. To evaluate crosslines, a 0.5 meter CUBE surface using strictly mainscheme lines, and a 0.5 meter CUBE surface using strictly crosslines were created. From these two surfaces, a difference surface (mainscheme - crosslines = difference surface) was generated using Pydro’s Compare Grids tool at a 0.5 meter resolution (Figure 5), and is submitted in the Separates II Digital Data folder. Statistics show the mean difference between the depths derived from mainscheme and crosslines was 0.06 meters with mainscheme being deeper and 95% of nodes falling within 0.12 meters (Figure 6). For the respective depths, the difference surface was compared to the allowable NOAA uncertainty standards using Compare Grids. In total, 99.5% of the depth differences between mainscheme and crossline data were within allowable NOAA uncertainties (Figure 7).F00795 Crossline Comparison Overviewfile:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/XL_Diff_Overview.JPGF00795 Crossline Comparison Statisticsfile:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/F00795_MS_Only_50cm-F00795_XL_Only_depth_delta.pngF00795 Crossline Comparison NOAA Allowable Uncertainty Statisticsfile:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/F00795_MS_Only_50cm-F00795_XL_Only_fracAllowErr_Freq.pngCrosslineData 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 F00795 Data Log spreadsheet. All data logs are submitted digitally in the Processing Logs folder.Data LogsFinalized surfaces were analyzed using the Pydro QC Tools Grid QA feature and the results are shown in Figure 8 below. Density requirements for F00795 were achieved with at least 99.5% of finalized surface nodes containing five or more soundings as required by HSSD Section 5.2.2.3. The few nodes that did not meet density requirements are due to sparse data in the outer beams. For individual graphs (per surface) of density requirements, see the Grid QA folder located in Appendix II.F00795 Surface Density Statisticsfile:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/F00795_MB_MLLW_50cm.QAv5.density.pngData DensityFliers were analyzed using the Pydro QC Tools Flier Finder tool. Two fliers were flagged. Both of these fliers are located on the obstruction in the area and are thus not considered spurious soundings. For information on the QC Tools settings and the results, see the QC Tools folder located in th Appendix II.Flier FinderF00795 data were reviewed in CARIS HIPS and SIPS for holidays in accordance with Section 5.2.2.3 of the HSSD. Three holidays which meet the 3 by 3 node definition were identified via Pydro QC Tools Holiday Finder tool. This tool automatically scans finalized surfaces for holidays as defined in the HSSD and was run in conjunction with a visual inspection of all surfaces by the hydrographer. These holidays were unfortunately found after the vessel had hauled out for winter repair and could not be obtained. The hydrographer strongly believes there to be no dangers to navigation in these areas based on surrounding data. A F00795_Holidays .hob file showing the location of these holidays is included in appendix II of this report.HolidaysCasts were conducted at a minimum of one every 4 hours during 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. Multibeam data on F00795 contains some evident outer beam spreading (Figure 9) especially in the ASV 008 data. This is caused by sound speed variations in the area, as well as areas of soft mud and silt seafloor. In areas where the beam spreading was obvious, rather than a true seafloor feature, the spurious soundings were rejected and surfaces recomputed. These soundings were rejected manually.F00795 Sound Velocity Outer Beam Spreading Examplefile:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/SV.PNGSound SpeedF00795 contains one designated sounding in accordance with HSSD Section 5.2.1.2.3. This designated sounding represents a submitted DTON and is included in the FFF. One DTON report was submitted for this project. The report is included in Appendix II of this report and details the object found and its location. The object is also included in the FFF. Figure 10 shows a 3D sonar image of the object.F00795 DTON 3D Image (colored by survey line)file:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/DTON_3d.JPGDesignated SoundingsKongsberg EM2040 stores the backscatter data in the .all file. The data were processed using the Caris SIPS Backscatter tool for data quality assurance (Figure 11). The data were sent to the Pacific Hydrographic Branch for processing. Backscatter data cannot be logged by the Picotech PicoMB and is thus not processed or included in this dataset.F00795 Kongsberg MBES Backscatter Overviewfile:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/F00795%20Backscatter%20overview.JPGBackscatterThe navigation data for MBES data collected by the ASV was reviewed by the hydrographer. Data was occasionally collected through turns if current or wind forces kept the ASV from hitting the end gates. In order to ensure high quality data, large turns at the ends of track lines were rejected from the navigation data.ASV Navigation EditingVessel kinematic data were post-processed using Applanix POSPac processing software and Single Base 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. For further details regarding the processing and quality control checks performed, see the F00795 POSPAC Processing Logs spreadsheets located in the Separates folder. During real-time acquisition, ASV008 and Bay Hydro II 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 F00795.ERS methods were used as the final means of reducing F00795 to MLLW for submission. Data were reduced using the VDATUM model S-E937_VDatumLimits_100m_NAD83-MLLW_geoid12b.csar provided by the project manager.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 Survey Summary 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, Standing and 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 Survey Summary Report. LT Patrick J DebroisseChief of Party2019-11-11LTJG Patrick LawlerJOIC2019-11-11This hydrographic survey was acquired in accordance with the requirements defined in the Project Instruction S-E937-BH2-19.38.36630576.37592538.36079176.366438F00795 Coverage overlaid on ENC US5MD21M.file:///D:/SE937BH219/Surveys/F00795/Office_Processing/Reports_office/DR%20Images/LCP_Coverage.JPGThere are submerged pilings off of Little Cove Point in the approximate position of 38° 21.836'N 076° 22.222W. The location is in the area of a registered pound net, pound net site 601, which has been removed. It is also reported that a number of poles and net remain submerged within 2 - 3 feet of below the surface. The waterman reported the submerged pilings in positions: 38°21'50.16"-076°22'-13.32' and 38°21'46.5"-076°22'13.26". The USCG reported end points of the registered net are 38°21'48.96 - 076°22'24.96' and 38°21'.96"-076°22'13.44". The Bay Hydro II was assigned to investigate the location of the reported obstructions.