OPR-H355-KR-18Florida KeysFlorida Keys National Marine Sanctuary and VicinityeTrac, IncH131601Complete Coverage MBES with Backscatter3 Nautical Miles East of Dry TortugasFloridaUnited States400002018David Neff, ACSM C.H. Basic Hydrographic Survey2018-07-192018-09-192019-01-12Multibeam Echo SounderMultibeam Echo Sounder BackscattermetersUniversal Transverse Mercator (UTM)UTCAtlantic Hydrographic BranchAll times are UTC. The purpose of this survey is to update existing NOS nautical charts. H13160 will cover approximately 50 square nautical miles of survey area 3 nautical miles east of Dry Tortugas. SUBCONSULTANT: Geodynamics LLC, 310A Greenfield Dr., Newport, NC 98570 ContractoreTrac Inc. conducted hydrographic survey operations in the Florida Keys National Marine Sanctuary and surrounding vicinity. H13160 covers approximately 50 square nautical miles of survey area. 1044 linear nautical miles were acquired during the survey. H13160 is located approximately 3 nautical miles east of Dry Tortugas, FL. Survey was conducted within these limits between September 20, 2018 (DN263) and January 12, 2019 (DN012).24.6213882.75246124.51639782.619222Survey Limits Overview (light blue area)SUPPORTFILES\H13160_SURVEY_LIMITS_OVERVIEW.PNGSurvey Limits (black line)SUPPORTFILES\H13160_SURVEY_LIMITS.PNGAll data were acquired in accordance with the requirements in the Project Instructions and specifications set forth in the Hydrographic Survey Specifications and Deliverables 2018 Edition (HSSD 2018).The purpose of this survey is to update existing National Ocean Service (NOS) nautical charts.The entire survey is adequate to supersede previous data.Survey H13160 is accurate to International Hydrographic Organization (IHO) Order 1a as required per the HSSD 2018.Survey Coverage was in accordance with the requirements in the Project Instructions and HSSD 2018. H13160 was surveyed to Complete Coverage with backscatter standards set forth in the HSSD 2018. Survey CoverageSUPPORTFILES\H13160_SURVEY_COVERAGE.PNGSurvey Coveragefile:///H:/Survey/H13160_H355_KR_18/AHB_H13160/01_SAR/Reports/Survey/Descriptive_Report/Report/SupportFiles/H13160_Survey_Coverage.PNGTaku01780000020Marcelle08240000040001002000004204.2350000502018-09-202018-09-212018-09-222018-09-232018-09-242018-09-252018-09-262018-09-272018-09-282018-09-292018-11-082018-11-092018-11-102018-12-022018-12-032018-12-042018-12-052018-12-152018-12-162019-01-12Refer 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 Marcelle452.6R/V Taku100.6The R/V Marcelle is a 45 meter steel-hulled vessel equipped with a custom over-the-side (port) multibeam pole mount. The R/V Taku is a 10 meter aluminum catamaran equipped with a custom stern multibeam pole mount.Kongsberg 2040CMBESR2Sonic2024MBESApplanixPOSMV 320 V5Positioning and Attitude SystemAMLBase.XSound Speed SystemAMLSmart.XSound Speed SystemeTraceTrac MVPSound Speed SystemNote: R/V Marcelle utilized a dualhead Kongsberg 2040C multibeam, an eTrac-built MVP and an AML Base.X for sound speed system and a POSMV 320 V5 for the positioning system. R/V Taku utilized a dualhead R2Sonic 2024 multibeam echosounder system, an AML Smart.X for the sound speed system and a POSMV 320 V5 for the positioning system. A comparison of crossline mileage to mainscheme mileage yields a crossline percentage of 4.23%, and is noted to be above the required 4%. A beam-to-beam statistical analysis was performed using the Cross Check tool in Qimera. A 2 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. Note: This surface was created for QC only and is not submitted as a surface deliverable. The beam-to-beam crossline comparison report generated through the Qimera Cross Check tool is included in Separates II. Below is a histogram of the crossline comparison statistics showing IHO Order 1a compliance per beam.H13160 Crossline Comparison SUPPORTFILES\H13160_CROSSCHECK.PNGR/V Taku202R/V Marcelle202Standard deviation and uncertainty layers of the Dynamic Surface were utilized during data processing to search for features, water column noise, and systematic errors. IHO Order 1a uncertainty specification was met by 100% of the nodes. The final Bathymetric Attributed Grid (BAG) surface's uncertainty was generated through the NOAA QC Tools and an image of the results is located below. For H13160 the following percentages represent the results of the TPU testing: Complete Coverage MBES (Finalized 1m CUBE weighted Dynamic Surface in NOAA QC Tools) = 99.5+% of nodes are within the allowable TPU. Complete Coverage MBES (Finalized 2m CUBE weighted Dynamic Surface in NOAA QC Tools) = 99.5+% of nodes are within the allowable TPU. H13160 Finalized 1m Complete Coverage MBES TPU StatisticsSUPPORTFILES\H13160_MB_1M_MLLW_FINAL_TVUQC.PNGH13160 Finalized 2m Complete Coverage MBES TPU StatisticsSUPPORTFILES\H13160_MB_2M_MLLW_FINAL_TVUQC.PNGDepth differences between junctioning surveys were evaluated using the JunctionTrac program, developed in-house by eTrac Inc. 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.H13161400002018eTrac IncSThe junction comparison between H13160 and H13161 will be submitted with the H13161 DR. Sonar 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.Sound Speed Refraction Refraction errors were noted during acquisition and attempts to mitigate the error were made upon discovery (i.e. increase sampling rate). When sound speed errors were not alleviated during acquisition, various methods of sound speed correction were evaluated and applied in post-processing. Where over-lap allowed, beam and angle filters were applied to reduce the extent of the error on the outer beams of the affected lines. Despite best practices, there are individual survey lines that exceed allowable vertical uncertainty for sound speed. However, these offsets do not degrade quality of the CUBE surfaces, as 99.97% of the 1m Final CUBE surface grid nodes and 99.99% of the 2m Final CUBE surface grid nodes meet the maximum allowable TVU defined in the 2018 HHSD.Example of Vertical Offset SUPPORTFILES\H13160_EXAMPLE_OF_VERTICAL_OFFSET.PNGSVP casts were generally taken every 2 hours. Ocassionally casts would exceed a 2 hour frequency, however would never exceed a 4 hour frequency. On R/V Marcelle and R/V Benthos casts were applied in both QPS QINSy and Kongsberg SIS acquisition software at the time of the cast. On 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 realtime. 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 realtime 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 EvaluationIn 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 Inc. 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 H13160 the following percentages represent the results of the density query: Complete Coverage MBES (Finalized 1m CUBE weighted Dynamic Surface ) = 99.5201% of nodes are composed from at least 5 soundings. Complete Coverage MBES (Finalized 2m CUBE weighted Dynamic Surface ) = 99.9682% of nodes are composed from at least 5 soundings.H13160 Finalized 1m Complete Coverage MBES Density DistributionSUPPORTFILES\H13160_DENSITYTRAC_1M_FINAL.PNGH13160 Finalized 2m Complete Coverage MBES Density SummarySUPPORTFILES\H13160_DENSITYTRAC_2M_FINAL.PNGAll 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 ALL and DB files. Every effort was made in the field to collect quality backscatter data while maintaining the primary mandate of high quality bathymetric data. While no processing or analysis of backscatter was required, eTrac Inc. verified coverage and general quality of the backscatter data collected. A beam intensity window was monitored in Qinsy during aquisiton to ensure backscatter data collection. Raw backscatter data were viewed in QPS FMGeocoder to further confirm collection criteria had been met. Shown below is an example of the unprocessed backscatter mosaic from H13160 DN269.Raw backscatter from R/V Marcelle (DN269)SUPPORTFILES\H13160_BACKSCATTER_DN269_MA.PNGNo Feature Object Catalog was used. Qimera was used as the primary processing software, which included feature management.H13160_MB_1m_MLLWCUBE110.6420NOAA_1mComplete MBESH13160_MB_2m_MLLWCUBE21831.47NOAA_2mComplete MBESA 1m and 2m surface are provided meeting complete coverage MBES with backscatter specifications for H13160.H13160 Delivered CUBE weighted Dynamic Surface Coverage Graphic (1m)SUPPORTFILES\H13160_1M_SURFACE_COVERAGE.PNGH13160 Delivered CUBE weighted Dynamic Surface Coverage Graphic (2m)SUPPORTFILES\H13160_2M_SURFACE_COVERAGE.PNGThe vertical control methods are further addressed in the HVCR and DAPR.Mean Lower Low WaterVDatumITRF_to_MLLW_FL_KEYS.binIn order to reference soundings to MLLW, a VDatum separation method was applied to the Qinsy DB files via a separation file in the aquisition software. Note: The vertical control methods are further addressed in the HVCR and DAPR.North American Datum of 1983 (NAD83)UTM Zone 17NA chart comparison was conducted for H13160 using Qimera and Caris HIPS and SIPS. Contours and soundings were compared against the largest scale ENC US4FL92M to accomplish the chart comparison. This ENC does not cover the entire survey of H13160 and therefore ENC US3FL90M was included to complete the chart comparison. The methods and results of the comparison are detailed below. Contour Comparison Method: Using the 2 meter CUBE weighted Dynamic Surface, the 60 foot contour was generated in Qimera and displayed against the charted contour. Additionally, the 2 meter CUBE weighted Dynamic Surface was viewed by a custom color band range based on the contour intervals (6ft, 12ft, 18ft, 30ft, 60ft). The results of the comparison are described below, followed by 1-2 images of example areas. Sounding Comparison Method: Using the same 2m CUBE weighted Dynamic surface, soundings were generated in Caris HIPS and SIPS. Soundings were displayed against the charted soundings and a visual comparison was made. The results of the comparison are described below, followed by 1-2 images of example areas.US4FL92M80000102016-05-242016-05-23falseContour Comparison Results: In general the 60 foot contour has receded inward towards the SE corner of H13160, ranging approximately 0 to 2000 feet from the charted contour. Multiple shoals distinguished by the 60 foot contour have formed in this area, differing from the continuous charted contour. Sounding Comparison Results: In areas were the contour had changed, as noted above, and where a feature was detected, soundings differ from the charted depths. In general for H13160, the soundings are in variable agreements with the chart. Soundings are generally within 3 to 5 feet from the chart, although there are soundings that differ 1 to 2 feet from the chart, as well as soundings that differ 6 to 10 feet from the chart. Depth differences are not biased in any particular direction to support a systematic error. H13160 60ft Contour Comparison (US4FL92M)SUPPORTFILES\H13160_CONTOUR_COMPARISON_US4FL92M.PNGH13160 Soudning Comparison (US4FL92M)SUPPORTFILES\H13160_SOUNDING_COMPARISON_US4FL92M.PNGUS3FL90M180000202017-11-172017-11-16falseContour Comparison Results: In general the 60 foot contour has receded inward towards the SE corner of H13160, ranging approximately 0 to 5000 feet from the charted contour. Multiple shoals distinguished by the 60 foot contour have formed in this area, differing from the continuous charted contour. Sounding Comparison Results: In areas were the contour had changed, as noted above, and where a feature was detected, soundings differ from the charted depths. In general for H13160, the soundings are in variable agreements with the chart. Soundings are generally within 3 to 5 feet from the chart, although there are soundings that differ 1 to 2 feet from the chart, as well as soundings that differ 6 to 10 feet from the chart. Depth differences are not biased in any particular direction to support a systematic error. H13160 30ft and 60ft Contour Comparison (US3FL90M)SUPPORTFILES\H13160_CONTOUR_COMPARISON_US3FL90M.PNGH13160 Sounding Comparison (US3FL90M)SUPPORTFILES\H13160_SOUNDING_COMPARISON_US3FL90M.PNGNo AWOIS Items were assigned for this survey.No Maritime Boundary Points were assigned for this survey.There was 1 charted features assigned to H13160. The assigned feature is retained 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 0XXX). Refer to the FFF for determinations and recommendations of each feature.There were 5 new features found in H13160 and added to the Final Feature File (FFF). Each feature was given a unique identifier in the "userid" field of the .000 S-57 file (format 0XXX). Refer to the FFF for determinations and recommendations of each feature. 5H13160_DtoN_01_1-5-72019-01-17H13160_DtoN_3-42019-01-30There were 2 DtoNs reports submitted for this survey which included 5 features in total, found in H13160, and added to the Final Feature File (FFF). Refer to the FFF for determinations and recomendations of each feature. Note: All DtoNs were included in the number of new, uncharted features within section D.1.5.No shoals or hazardous features exist for this survey.No channels exist for this survey.5 locations of drop camera imagery were obtained in accordance with Appendix I of the Project Instructions in areas designated by the feature object class springs (SPRING) in the Project Reference File (PRF). A brief description of the results is listed below. A1: sand A2: sand A3: sand A4: sand, coral A5: sand Detailed information and images of the bottom samples listed above 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 AX).No shoreline exists for this survey.No prior surveys exist for this survey.No AtoNs exist for this survey.No overhead features exist for this survey.No submarine features exist for this survey.1 uncharted ferry route is located within the survey limits of H13160. The ferry route is called Key West-Fort Jefferson or Dry Tortugas Ferry. The ferry terminals for this route are located at the Key West Ferry Building in Key West, Florida and the Fort Jefferson Boat Dock in Dry Tortugas, Florida.Ferry Route (blue line)SUPPORTFILES\H13160_FERRYROUTE.PNGFerry Terminal - Key West Ferry BuildingSUPPORTFILES\H13160_FERRYTERMINAL_KEYWEST.PNGFerry Terminal - Fort Jefferson Boat DockSUPPORTFILES\H13160_FERRYTERMINAL_FORTJEFFERSON.PNGNo platforms exist for this survey.No significant features exist for this survey.No construction or dredging exist for this survey.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 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.David R. Neff, C.H.VP of Survey, eTrac Inc.2019-02-22