OPR-E351-KR-22 Southwest Chesapeake Bay Rivers Southwest Chesapeake Bay eTrac H13770 6 Option 1 Sheet McKans Bay to Old City Dock Virginia United States 10000 2023 David Neff, C.H. Basic Hydrographic Survey 2023-03-08 2023-04-04 2023-12-13 Multibeam Echo Sounder Multibeam Echo Sounder Backscatter Side Scan Sonar meters UTC Atlantic Hydrographic Branch All times are UTC. The purpose of this survey is to update existing NOS nautical charts. H13770 covers approximately 28 square nautical miles of the Rappahannock River from McKans Bay to Old City Dock, Virginia. 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. CC0-1.0 (NOAA Field Units) CC0-1.0 https://creativecommons.org/publicdomain/zero/1.0/ https://creativecommons.org/publicdomain/zero/1.0/legalcode These data were produced by NOAA and are in the public domain within the United States. NOAA waives any potential copyright and related rights in these data worldwide through the Creative Commons Zero 1.0 Universal Public Domain Dedication (CC0). Contractor eTrac conducted hydrographic survey operations in the Rappahannock River, Virginia. H13770 covers approximately 28 square nautical miles of survey area. 1107.91 linear nautical miles were acquired during the survey. Survey was conducted within these limits between April 4, 2023 (DN094) and December 13, 2023 (DN347). 38.295249999999996 77.45246111111112 37.741480555555555 76.71705833333334 All data were acquired in accordance with the requirements in the Hydrographic Survey Project Instructions and specifications set forth in the Hydrographic Survey Specifications and Deliverables 2022 Edition (HSSD 2022). Survey Limits Overview (light blue area) file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_SurveyLimits_Overview.png Survey Limits (black line) file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_SurveyLimits.png The principal objective of the Southwest Chesapeake Bay Rivers project is manifold. This survey will supply forecasters and decision makers at the NOAA National Water Center with bathymetry data for critical hydrodynamic modeling. This data is necessary to understand the timing of rapid river stage increases and decreases, the duration of high water, inundation, or drought. The temperature and salinity distributions provided in flow models will support the Rappahannock oyster industry. This survey will emphasize features that effect safe navigation and update the Office of Coast Survey nautical charts and services. The entire survey is adequate to supersede previous data. Survey H13770 is accurate to International Hydrographic Organization (IHO) Order 1a as required per the HSSD 2022. All waters in survey area Complete Coverage Option B All waters in survey area 2 to 8 m water depth Sidescan Sonar Data may be aquired at an altitude of 6-20% of the range-scale All waters in survey area in which a side scan sonar contact indicates a natural feature, i.e. mounds, with height greater than 1 meter. 1. Inside the traffic corridor and in areas of low under keel clearance, investigate all contacts to complete coverage standards in accordance with HSSD requirements. 2. Outside the traffic corridor, if discrete features are located within 8 mm at the largest scale chart, then the most significant feature within the 8 mm radius should be investigated (with 2 investigation lines perpendicular to each other). Survey coverage was in accordance with the requirements listed above and in the HSSD 2022. Note: Survey coverage did not extend to the entire survey boundary as the Navigable Area Limit Line (NALL) was reached. However there are occasionally small gaps in the side scan mosaic along the NALL due to the inability to safely tow the side scan up to the NALL which would require operating the vessel beyond the NALL. Gaps in complete survey coverage exist due to the presence of recreational vessels in the area. An example of a coverage gap due to recreational vessels is presented below. Survey Coverage with combinded MBES and SSS file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_SurveyCoverage_MBES_SSS.png Data coverage gap caused by recreational vessels file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_DataCoverageGap_Safety.png R/V Endeavor 0.0 0.0 0.0 0.0 0.0 127.23 0.0 11.98 0.0 R/V Pulse 0.0 0.0 0.0 0.0 0.0 387.94 0.0 48.14 0.0 R/V Spectrum 0.0 0.0 0.0 0.0 0.0 338.86 0.0 13.02 0.0 R/V Taku 0.0 0.0 0.0 0.0 0.0 168.01 0.0 12.74 0.0 0.0 0.0 0.0 0.0 0.0 1022.03 0.0 85.87 0.0 8.4 9 0 0 0 28.23 2023-04-04 2023-04-05 2023-04-06 2023-04-07 2023-04-23 2023-04-25 2023-04-26 2023-04-27 2023-04-29 2023-04-30 2023-05-03 2023-05-04 2023-05-06 2023-05-07 2023-05-08 2023-05-09 2023-05-10 2023-05-11 2023-05-12 2023-05-13 2023-05-14 2023-05-15 2023-05-16 2023-05-17 2023-05-18 2023-05-24 2023-05-25 2023-05-26 2023-09-28 2023-09-30 2023-10-01 2023-10-02 2023-10-03 2023-10-04 2023-10-05 2023-10-06 2023-10-07 2023-10-08 2023-10-09 2023-10-10 2023-10-11 2023-10-12 2023-10-13 2023-10-14 2023-10-15 2023-10-16 2023-10-17 2023-10-18 2023-10-19 2023-10-20 2023-10-21 2023-10-22 2023-10-23 2023-10-25 2023-12-13 On 12/13/2022 visual confirmation of assigned and new features were found using a hand held range finder, no MBES data was collected. Section A.5 is being registered as A.6 when the XML is printed to PDF ISK 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 are discussed in the following sections. R/V Endeavor 13.4 0.8 R/V Pulse 7.3 0.6 R/V Spectrum 6.7 0.6 R/V Taku 9.4 0.8 The R/V Endeavor is a 13.4 meter aluminum catamaran built by Armstrong Marine equipped with an over-the-side Pitman Arm Sonar Mount with a secondary tie point, a hydraulic A-frame and davit. The R/V Pulse is a 7.3 meter aluminum monohull equipped with a Universal Sonar Mount (USM) starboard multibeam pole mount and davit. The R/V Spectrum is a 6.7 meter aluminum monohull equipped with a Universal Sonar Mount (USM) starboard multibeam pole mount and davit. The R/V Taku is a 9.4 meter aluminum catamaran built by Armstrong Marine equipped with a Universal Sonar Mount (USM) stern multibeam pole mount, hydraulic A-frame and davit. MBES R2Sonic 2022 MBES R2Sonic 2024 Sound Speed System AML Oceanographic 3-RT Velocity Probe Sound Speed System AML Oceanographic MicroX SV Sound Speed System AML Oceanographic AML-3 LGR Sound Speed System AML Oceanographic BaseX2 Positioning and Attitude System Applanix POS MV WaveMaster Positioning and Attitude System Applanix POS MV OceanMaster Positioning System R2Sonic I2NS SSS EdgeTech 4125 SSS EdgeTech 4200 Note: R/V Endeavor utilized a single head R2Sonic 2024 multibeam echosounder system (MBES) with the exception of October 2023 when R/V Endeavor utilized a dual head R2Sonic 2022 MBES. R/V Endeavor also utilized an AML 3-RT for the surface sound speed system, an AML-3 LGR for the sound speed system, an R2Sonic I2NS for the positioning and attitude system, and an EdgeTech 4200 MP side scan sonar (SSS). R/V Pulse utilized a single head R2Sonic 2022 multibeam echosounder system (MBES) until May 10th 2023 when the MBES was exchanged for a single head R2Sonic 2024 MBES. R/V Pulse also utilized an AML 3-RT for the surface sound speed system, an AML-3 LGR for the sound speed system, an Applanix POSMV WaveMaster (POS MV 320 v4) for the positioning and attitude system, and an EdgeTech 4125 side scan sonar (SSS). R/V Spectrum utilized a single head R2Sonic 2024 multibeam echosounder system (MBES), an AML Micro.X for the surface sound speed system, an AML Base.X2 for the sound speed system, an Applanix POSMV WaveMaster (POS MV 320 v4) for the positioning and attitude system, and an EdgeTech 4125 side scan sonar (SSS). R/V Taku utilized a single head R2Sonic 2024 multibeam echosounder system (MBES), an AML 3-RT for the surface sound speed system, an AML Base.X2 for the sound speed system, an Applanix POSMV OceanMaster (POS MV 320 v5) for the positioning and attitude system, and an EdgeTech 4125 side scan sonar (SSS). A beam-to-beam statistical analysis was performed using the Cross Check tool in Qimera. A 1 meter Combined Uncertainty and Bathymetric Estimator (CUBE) weighted dynamic surface was created incorporating only the mainscheme lines and excluded crosslines. The Cross Check tool was used to perform the beam-by-beam comparison of the crossline data to the mainscheme surface. Comparisons showed excellent agreement, well above 95% of the allowable TVU. The percentage of crossline miles as compared to main scheme miles was 8.40% Note: This surface was created for QC only and is not submitted as a surface deliverable. Below is a histogram of the crossline comparison statistics showing IHO Order 1a compliance per beam. H13770 Crossline Comparison file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_XL_Crosscheck_Plot.jpg ERS via ERTDM 0.06 R/V Endeavor 0.05 0.2 R/V Pulse 0.05 0.2 R/V Spectrum 0.05 0.2 R/V Taku 0.05 0.2 In order for Qimera to export a BAG the H13770 surface needed to be divided into two sections. The NW half of H13770 has been exported as H13770_MB_1m_MLLW_Final_1of2, and the SE half of H13770 has been exported as H13770_MB_1m_MLLW_Final_2of2. The standard deviation uncertainty and the total vertical uncertainty (TVU) layers of the Dynamic Surfaces were utilized during data processing to search for features, water column noise, and systematic errors. IHO Order 1a uncertainty specification of was met by 100% of the nodes. In Qimera versions beginning in 2.5.1 and beyond, the user has the ability to export the Dynamic Surface to a Bathymetric Attributed Grid (BAG) with TVU layer. Using both BAGs, the percentage of nodes that fell within the TVU specification for each Dynamic Surface was calculated using the NOAA QC tools program. These results are shown in images below. Complete Coverage Option B MBES (Finalized 1m CUBE weighted Dynamic Surfaces (1of2 and 2of2) in NOAA QC Tools) =100.0% of nodes are within the allowable TVU. H13770 Finalized 1m MBES TVU Statistics 1of2 file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_MB_1m_MLLW_1of2.GQv6.tvu_qc.png H13770 Finalized 1m MBES TVU Statistics 2of2 file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_MB_1m_MLLW_2of2.GQv6.tvu_qc.png Depth differences between junctioning surveys were evaluated using the JunctionTrac program, developed in-house by eTrac. For each junction, each CUBE weighted dynamic surface's nodes were exported to an ASCII CSV file where the fields were (Easting, Northing, Depth) for each node. A 1 meter difference surface between the junctioning datasets was also created and exported to an ASCII CSV file where the fields were (Easting, Northing, Diff) for each node. The three ASCII CSV files were then loaded into the JunctionTrac program and junction statistics were computed. A file was also created in this process to locate any nodes from the difference surface that exceed the allowable TVU, which was imported into Qimera and any identified points from JunctionTrac were analyzed. Note: the difference surfaces were created for comparison efforts only and are not submitted as surface deliverables. H13771 20000 2023 eTrac SE The junction comparison was performed using all overlapping data between H13770 and H13771. Below is a histogram of junction comparison statistics showing the difference between the junctioning surfaces and allowable TVU as well as difference statistics. 100% of nodes were within allowable TVU. H13770 - H13771 Junction Comparison file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_H13771_JuntionTrac_Results.png H13770 - H13771 Difference Statistics file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_H13771_Junctions_DiffTrac.png Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR. None Exist There were no conditions or deficiencies that affected equipment operational effectiveness. None Exist There were no other factors that affected corrections to soundings. SVP casts were generally taken every 2 hours. Occasionally casts would exceed a 2 hour frequency, however would never exceed a 4 hour frequency. On R/V Endeavor, R/V Pulse, R/V Spectrum, and R/V Taku casts were applied in QPS Qinsy acquisition software at the time of the cast. Surface SVP measured at 1Hz was compared to surface speed from the current profile in real-time. If the surface velocity comparison was in excess of 2m/s at any time during survey operations, a new cast was taken. Surface sound speeds were compared in real-time and profile to profile for each cast on the vessel. Additionally, the processor reviewed profiles in Qimera to remove spurious readings within a cast, compare day-to-day casts, and to check distribution over the surveyed area, in order to better understand trends for efficient acquisition planning. All equipment and survey methods were used as detailed in the DAPR. Data Density Evaluation In order to determine if the density of the data met the specified 5 soundings per node, data density was evaluated using DensityTrac in the AmiTrac program, developed in-house by eTrac. Each finalized CUBE weighted dynamic surface's nodes were exported to a BBH file. The BBH file was then loaded into the DensityTrac program and density statistics were computed. For H13770 the following percentages represent the results of the density query: Complete Coverage MBES (Finalized 1m CUBE weighted Dynamic Surface) = 98.607% of nodes are composed from at least 5 soundings. H13770 Finalized 1m Set Line Spacing MBES Density Distribution file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_1m_DensityTrac.png All data reduction procedures conform to those detailed in the DAPR. All sounding systems were calibrated as detailed in the DAPR. Backscatter data were collected throughout the survey and are retained in the raw DB files. Every effort was made in the field to collect quality backscatter data while maintaining the primary mandate of high quality bathymetric data. eTrac verified coverage and general quality of the backscatter data collected daily. A beam intensity window was monitored in Qinsy during acquisition to ensure backscatter data collection. Raw backscatter data were viewed in QPS FMGeocoder (FMGT) to further confirm collection criteria had been met. After MBES data was fully processed and cleaned in Qimera, GSF files were exported and brought into FMGT and processed into backscatter mosaics grouped by acoustic frequency and survey system. NOAA Profile Version 2022 Feature Object Catalog, NOAA Profile Version 2022 was used only in CARIS. Qimera was used as the primary processing software. H13770_MB_1m_MLLW_FINAL_1of2 BAG 1 0.4 18.8 NOAA_1m Complete MBES H13770_MB_1m_MLLW_FINAL_2of2 BAG 1 0.8 18.4 NOAA_1m Complete MBES H13770_MBAB_2m_EN_400kHz_1of4 MB Backscatter Mosaic 2 N/A Complete MBES H13770_MBAB_2m_PU_400kHz_2of4 MB Backscatter Mosaic 2 N/A Complete MBES H13770_MBAB_2m_SP_400kHz_3of4 MB Backscatter Mosaic 2 N/A Complete MBES H13770_MBAB_2m_TA_400kHz_4of4 MB Backscatter Mosaic 2 N/A Complete MBES H13770_SSSAB_1m_400kHz_1of2 SSS Mosaic 1 N/A 100% SSS H13770_SSSAB_1m_400kHz_2of2 SSS Mosaic 1 N/A 200% SSS In order for Qimera to export a BAG the H13770 surface needed to be divided into two sections. The NW half of H13770 has been exported as H13770_MB_1m_MLLW_Final_1of2, and the SE half of H13770 has been exported as H13770_MB_1m_MLLW_Final_2of2. Both 1m surfaces are provided meeting complete coverage MBES with backscatter specifications for H13770. A 1m mosaic is provided meeting complete coverage with 100% SSS specifications for H13770. A separate 1m mosaic is also provided meeting specifications for the 200% disproval radii. H13770 Finalized 1m CUBE Weighted Dynamic Surface Coverage file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_SurfaceCoverage_MBES_1m.png H13770 Finalized 2m MBAB mosaics file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_MosiacCoverage_MBAB.png H13770 Finalized 1m SSS mosaic file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_SurfaceCoverage_SSSAB_1m.png Additional Task: Final Data Submission - Grids An additional assigned task for this sheet was to include interpolated grids in Mean Lower Low Water (MLLW) and North American Vertical Datum of 1988 (NAVD88) datum. Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR and DAPR. Mean Lower Low Water ERS via ERTDM OPR-E351-KR-22_NAD83-MLLW.qgfvom In order to reference soundings to Mean Lower Low Water Datum, a separation model was provided by NOAA and was applied to the Qinsy DB files via a .qgfvom separation file in the acquisition software. North American Datum 1983 (2011) Projected UTM 18 RTX Applanix PosPac MMS was utilized to post process real time positioning data utilizing Trimble's PP-RTX implementation of Trimble CenterPoint RTX to create a Smoothed Best Estimate of Trajectory (SBET). GNSS satellite corrections were received on each vessel using either the G2+ or G4+ carrier signal from the Marinestar Global Correction System maintained by Fugro. Additional Task: Final Data Submission- Grids An additional assigned task for this sheet was to include interpolated grids in North American Vertical Datum of 1988 (NAVD88) datum. In order to reference soundings to NAVD88 Datum, a separation model was provided by NOAA and was applied to the gridded MLLW data in QGIS. A chart comparison was conducted for H13770 using Pydro CA tools, Qimera, and Caris HIPS and SIPS. Survey data were compared against the largest scale ENC to accomplish the chart comparison. Details of the ENC used are listed below. US5VA63M, scale: 40000, edition: 19, update application date: 01/06/2022, issue date: 03/18/2022 Throughout survey operations sounding comparisons between the charted depths and the surveyed depths were analyzed to identify depth discrepancies. Using 1 meter CUBE weighted Dynamic surfaces, soundings were generated in the "Sounding Selection" tab of Pydro CA tools. Soundings were displayed against the charted soundings and a visual comparison was made in Caris HIPS and SIPS. Additionally, potential DtoNs and discrepancies were generated using the "DTM vs Chart" tab of Pydro CA tools. The results were displayed through CA tools and investigated in CARIS HIPS and SIPS and Qimera. An overview image of the generated soundings on chart is included below. Results of the chart comparison are included in the following sections. Generated Soundings used for Chart Comparison (US5VA63M) file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_ChartComparison_US5VA63M.png US5VA63M 40000 19 2022-01-06 2022-03-18 There were 19 DtoNs found in H13770, and added to the Final Feature File (FFF). Each feature in the FFF has been given a unique identifier in the "userid" field of the .000 S-57 file (format 6XXXXX). Refer to the FFF for determinations and recommendations of each feature. The DtoNs were submitted in the following Danger to navigation reports: H13770_DtoN_01-14 H13770_DtoN_16-1 H13770_DtoN_17-20 There were 401 charted feature assigned to H13770 that are included in the Final Feature File (FFF). Each feature in the FFF has been given a unique identifier in the "userid" field of the .000 S-57 file (format 6XXXXX). Refer to the FFF for determinations and recommendations of each feature. 107 new features were found in H13770. Each feature in the FFF has been given a unique identifier in the "userid" field of the .000 S-57 file (format 6XXXXX). Refer to the FFF for determinations and recommendations of each feature. Note: DtoNs are not included in the number of new features in this section. DtoNs can be found separately in section D.1.2. Note: Throughout H13770 there were temporary aids for fishing gear. These aids were not included in the FFF due to their temporary nature. Arnolds Bar Channel, Hoskins Creek Entrance Channel, and Mangoright Bar Channel were assigned as a dredge area. No discrepancies were found within our survey extents. Hoskins Creek Entrance Channel Mangoright Bar Channel were not fully addressed as they were partially inshore of NALL. The dredge areas were not included in the FFF following investigations requirements. Throughout H13770 there were temporary aids for fishing gear. These aids were not included in the FFF due to their temporary nature. One charted ATON was found to be slightly off station and was reported to the U.S. Coast Guard. All other ATONs within the survey area were found on station. No Maritime Boundary Points were assigned for this survey. 9 bottom samples were obtained in accordance with section 7.1 of the HSSD 2022 in areas designated by the field through discussions with our COR. Detailed information and images of the bottom samples are located in the Final Feature File (FFF). Each bottom sample has been given a unique identifier in the "userid" field of the .000 S-57 file (format FX). There were 14 overhead features assigned to H13770. 6 overhead features were visually confirmed and no discrepancies were found. 8 overhead features were not addressed as they were inshore of NALL. The overhead features were not included in the FFF following investigation requirements. No submarine features exist for this survey. There were 20 offshore platforms assigned to H13770 that are included in the Final Feature File (FFF). Each feature in the FFF has been given a unique identifier in the "userid" field of the .000 S-57 file (format 6XXXXX). Refer to the FFF for determinations and recommendations of each feature. No ferry routes or terminals exist for this survey. Hundreds of circulars to oblong mounds with heights up to 4m have been identified. The mounds are found in water depths ranging from 3 to 10 meters. The individual mounds and groupings of mounds tend to be elongate in the direction of current flow with long axis length of individual mounds ranging from a few meters to hundreds of meters. Groupings of mounds can be a kilometer in length. The mounds have a significantly higher acoustic reflectivity than the surrounding riverbed. Riverbed scouring is commonly observed along the margins of mounds. H13770 Abnormal Seafloor Condition - Mounds file:///H:/OPR-E351-KR-22/Surveys/H13770/01_HDR/Reports/Descriptive_Report/SupportFiles/H13770_Abnormal_Seafloor_Conditions_Mounds.png There were 146 shoreline construction features assigned to H13770 that are in the Final Feature File (FFF). There was 1 new shoreline construction feature added to the FFF. Each feature in the FFF has been given a unique identifier in the "userid" field of the .000 S-57 file (format 6XXXXX). Refer to the FFF for determinations and recommendations of each feature. 17 dredge areas were assigned to H13770. 2 dredge areas were not fully addressed due to NALL. 4 dredge areas were not addressed as they were inshore of NALL. No discrepancies were found within our survey extents. No new surveys or further investigations are recommended for this area. No new ENC scales 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 CUBE surfaces, 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 and Specifications Deliverables Manual, 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. This revision of the DR includes the updated number of features and AtoNs found in H13770. David Neff, CH Chief of Party 2024-03-15