OPR-H355-KR-21 Key West, FL Key West Geodynamics H13429 3 East of Key West Florida United States 5000 2021 David J. Bernstein, CH, PLS, GISP Navigable Area 2021-02-17 2021-04-15 2021-06-23 Multibeam Echo Sounder Multibeam Echo Sounder Backscatter meters UTC Pacific Hydrographic Branch 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 17N, 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 Contractors) CC0-1.0 https://creativecommons.org/publicdomain/zero/1.0/ https://creativecommons.org/publicdomain/zero/1.0/legalcode These data were produced under contract with NOAA and any potential copyright was assigned to NOAA. 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 Geodynamics LLC conducted a hydrographic survey in the assigned area of H13429 located east of Key West, Florida. Within H13429, all survey operations were conducted in accordance with the provided Statement of Work (SOW), Hydrographic Survey Project Instructions (PI), and the April 2021 National Ocean Service (NOS) Hydrographic Survey Specifications and Deliverables (HSSD). Any deviations from the aforementioned guidelines have been approved by the National Oceanographic and Atmospheric Administration (NOAA) Hydrographic Survey Division (HSD) Operations (OPS) branch and are documented in the survey correspondences. 24.561648 81.813768 24.484806333333335 81.62137799999999 Data were acquired to the survey limits in accordance with the requirements listed in the PI and the HSSD. Overview of project survey limits (H13429 shown in blue), overlaid onto Charts 11439, 11442, and 11452 SupportFiles\Survey_Limits_Overview_H13429.png H13429 survey limits overlaid onto Chart 11442 SupportFiles\Survey_Limits_H13429.png This project is located within the Florida Keys National Marine Sanctuary, with survey areas focused along the outer reef shelf as well as Hawk Channel, which is located in between the Keys and the barrier reef. Much of the 149 SNM survey area has not been surveyed since the 1950s, and many commercial and recreational boaters utilize Hawk Channel and the waters surrounding the coral reef for fishing, recreation, and other uses. Conducting a modern bathymetric survey with concurrent backscatter data in this area will provide critical data for the updating of NOS nautical charting products and services to increase maritime safety near the waters of the Florida Keys, and help classify the habitat of the reefs. 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. Survey quality in H13429 meets or exceeds requirements set forth in the HSSD. Survey quality was assessed through visual inspection, the analysis of crosslines, and utilizing QC Tools to assess uncertainty and density. Additionally, junction analyses were conducted between overlapping data collected on this project and 2019 NOAA National Geodetic Survey (NGS) lidar data. For more information on methods and results of the survey data quality assessments for this survey, refer to section B.2 of this report. All waters in survey area Complete Coverage The entirety of H13429 was acquired with complete coverage in accordance with section 5.2.2.3 of the HSSD, as shown in Figure 3. All efforts were made to acquire survey data to the sheet limits or to the Navigable Area Limit Line (NALL), as defined in section 1.3.2 of the HSSD. An example of where survey limits were defined by NALL can be seen in Figure 4. H13429 survey coverage overlaid onto Chart 11442 SupportFiles\Survey_Coverage_H13429.png H13429 example of area where survey coverage was defined by the limits of safe navigation SupportFiles\Survey_Coverage_NALL_H13429.png R/V Benthos 0.0 575.69 0.0 0.0 0.0 0.0 0.0 28.08 0.0 R/V Chinook 0.0 611.68 0.0 0.0 0.0 0.0 0.0 36.61 0.0 0.0 1187.36 0.0 0.0 0.0 0.0 0.0 64.69 0.0 5.45 0 0 0 0 23.1 2021-04-15 2021-04-16 2021-04-17 2021-04-18 2021-04-19 2021-04-20 2021-04-21 2021-04-22 2021-04-23 2021-04-25 2021-04-26 2021-04-27 2021-04-28 2021-04-29 2021-05-06 2021-05-29 2021-05-30 2021-06-23 Refer to the OPR-H355-KR-21 Data Acquisition and Processing Report (DAPR) for a complete description of survey equipment and configurations, data acquisition procedures, data processing methods, quality control measures, and survey reporting methods. Additional information to supplement survey data and any deviations from the DAPR are discussed in the following sections. R/V Benthos 9.14 0.61 R/V Chinook 9.44 0.61 MBES Kongsberg Maritime EM 2040C Positioning and Attitude System Applanix POS MV 320 v5 Sound Speed System AML Oceanographic MicroX SV Sound Speed System AML Oceanographic BaseX Sound Speed System AML Oceanographic BaseX2 R/V Benthos and R/V Chinook utilized a dual-head Kongsberg EM 2040C multibeam system, a POS M/V 320 v5 positioning and attitude system, and an AML MicroX surface sound speed system. R/V Benthos utilized both an AML BaseX and AML BaseX2 sound speed profiling system. R/V Chinook utilized an AML BaseX2 sound speed profiling system. Multibeam crosslines acquired for H13429 totaled 5.45% of mainscheme acquisition. H13429 crosslines were collected and analyzed in accordance with section 5.2.4.2 of the HSSD. Crosslines were evaluated in CARIS HIPS with a detailed visual inspection followed by a thorough statistical analysis. To conduct the statistical analysis, a 1 m CUBE surface was generated with strictly mainscheme data and another, separate 1 m CUBE surface was generated with only crossline data. The mainscheme and crossline surfaces were analyzed using the Compare Grids tool in Pydro Explorer, which generated a difference surface and associated statistics. In addition to the direct statistics from the surface differencing, the tool assessed the difference surface statistics and computed the proportion of NOS total allowable vertical uncertainty (TVU) consumed by the mainscheme to crossline differences per surface node. The statistical results of the difference comparison show 95% of nodes falling within +/- 0.08 m, with a mean difference of 0.00 m (Figure 5). Additionally, 99.5+% of the difference surface nodes met or exceeded TVU specifications, as described in section 5.1.3 of the HSSD. H13429 crossline to mainscheme difference statistics SupportFiles\Crossline_Stats_H13429.png ERS via VDATUM 0.089 0.0 R/V Benthos 2.00 0.05 R/V Chinook 2.00 0.05 The Tide Measured uncertainty was prescribed in the PI (0.089 m), and this was the value utilized in the TPU calculation (Table 7). It should be noted a small discrepancy was discovered between the uncertainty value listed in the PI (0.089 m) and the uncertainty value in the .log file accompanying the utilized separation model (0.094 m). Please refer to DR Appendix II Supplemental Records for additional information and related correspondence with the HSD Project Manager. The finalized CUBE surface was analyzed using the HydrOffice QC Tools Grid QA tool to assure 95% of the surface nodes meet TVU specifications. The results of the Grid QA tool determined that the finalized CUBE surface met or exceeded the TVU specifications, as shown in Figure 6. Finalized 1 m CUBE surface TVU statistics for H13429 SupportFiles\TVU_Stats_Final_H13429.png H13429 junctions with H13430 and 2019 NOAA NGS lidar data, registry number FL-1806-TB-C (Figure 7). Data overlap between H13429 and the adjacent surveys were attained. To conduct the junction analyses, similar to section B.2.1 of this report, the Pydro Compare Grids tool was utilized. The inputs for this tool were the surfaces for each individual survey at matching resolutions. In addition to the statistical results of the junction analyses, the resultant difference surfaces were visually inspected and CARIS HIPS Subset Editor was used to examine overlapping data for consistency, agreement between surveys, and confirming data met TVU specifications. Overview of H13429 junction surveys SupportFiles\Junction_Overview.png H13430 5000 2021 Geodynamics W The statistical results of the difference comparison show 95% of nodes falling within +/- 0.09 m, with a mean difference of 0.00 m (Figure 8). Additionally, 99.5+% of the difference surface nodes meet or exceed TVU specifications, as described in section 5.1.3 of the HSSD. Junction analysis between H13429 and H13430 SupportFiles\Stats_Junction_Diff_H13429_and_H13430.png FL-1806-TB-C 0 2019 NOAA NGS - Lidar N The statistical results of the difference comparison show 95% of nodes falling within +/- 0.15 m, with a mean difference of 0.04 m (Figure 9). Additionally, 99.5+% of the difference surface nodes met or exceed TVU specifications, as described in section 5.1.3 of the HSSD. Junction analysis between H13429 and FL-1806-TB-C SupportFiles\Stats_Junction_Diff_H13429_and_FL-1806-TB-C.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. Sound speed casts were acquired at least once every four hours. Casts were often conducted more frequently (~every two hours) than this time interval because of the dynamic water properties in the survey area. Surface sound speed was compared in real-time to the sound speed profile. When the comparison differed by more than 2 m/s, a new sound speed profile was acquired. Additionally, QPS Qinsy and Kongsberg SIS provided a real-time visual assessment of data quality (standard deviation grids, bathymetric grids, swath views) aiding the hydrographer in determining when a new cast was required. For more detailed information on sound speed methods, please refer to the DAPR. All equipment and survey methods were used as detailed in the DAPR. Holidays The finalized 1 m CUBE surface was analyzed using HydrOffice QC Tools Holiday Finder to determine if the surface contained holidays, as described in section 5.2.2.3 of the HSSD. The tool scanned the CUBE surface, identifying any holidays, and generated an S-57 file to illustrate the locations of holidays. All holidays identified were within NALL or outside of the sheet limits. Another method of holiday evaluation was to visually pan the CUBE surface to identify holidays. The hydrographer would often alter the surface display (color ranges, symbology, shading) to help aid the hydrographer in identifying coverage gaps. The results reflected the same outcome as the tool, all holidays were within NALL or outside of the sheet limits. Density The finalized 1 m CUBE surface was analyzed using HydrOffice QC Tools Grid QA tool to assure data met the required density specifications. Density requirements were achieved for the finalized surface in H13429 with 99.5% of the 1 m surface nodes (Figure 10) containing at least five or more soundings, exceeding the specifications required by section 5.2.2.3 of the HSSD. Finalized 1 m CUBE surface density statistics for H13429 SupportFiles\Density_Stats_Final_H13429.png Flier Finder In addition to a visual inspection, the finalized 1 m CUBE surface was analyzed using HydrOffice QC Tools Flier Finder tool to assure data does not contain fliers (anomalous data as defined by QC Tools flier finding algorithms #2-5). While the Flier Finder tool flags surface fliers meeting a set criteria, it will also flag real surface features that meet the same criteria. Spurious soundings flagged by Flier Finder were cleaned until only the remaining flagged fliers were deemed valid aspects of the 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 collected and stored within the .ALL files. Backscatter data were processed for quality assurance purposes in QPS FMGT. Additionally, mosaics were created to assure the coverage and quality of the backscatter (Figure 11). Hydrographers in the field monitored backscatter intensities in real-time and made efforts to collect quality backscatter without hindering bathymetric data quality. Refer to the DAPR for more information on backscatter data acquisition and processing procedures. H13429 backscatter SupportFiles\Backscatter_H13429.png CARIS HIPS and SIPS 11.3.14 QPS FMGT 7.9.3 NOAA Profile Version 2021 H13429_MB_1m_MLLW_Final CARIS Raster Surface (CUBE) 1 2.24 13.5 NOAA_1m Complete MBES H13429_MB_1m_MLLW CARIS Raster Surface (CUBE) 1 2.24 13.5 NOAA_1m Complete MBES All surfaces submitted are in compliance with the complete coverage MBES requirements per section 5.2.2.3 of the HSSD. Designated Soundings H13429 contains 22 designated soundings in accordance with sections 5.2.1.2.3 and 7.4 of the HSSD. Of these, 16 designated soundings were created to facilitate feature management and best represent the least depths of features in the Final Feature File (FFF). Additionally, six designated soundings were utilized to override the gridded surface model and best represent the least depths of irregular coral mounds that did not meet criteria for inclusion in the FFF. These designated soundings were chosen prudently, with particular detail to navigational significance and the method in which coral mounds are represented on the chart. In the finalized CUBE surface, the CARIS HIPS Apply Designated Soundings function ensured designated sounding depths are retained in the finalized surface. Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR. Mean Lower Low Water ERS via VDATUM OPR-H355-KR-21_NAD83_VDatum_MLLW.csar Real-time positional data were corrected with G2+ Global Navigation Satellite System (GNSS) satellite corrections provided by the Fugro Marinestar Satellite-Based Augmentation System (SBAS). To improve the accuracy of the real-time data, real-time position and attitude data were post-processed using Applanix POSPac Mobile Mapping Solution (MMS) software. Trimble CenterPoint RTX correction methods were used to create Smoothed Best Estimate of Trajectory (SBET) files, which were applied to the survey data in CARIS HIPS. The provided separation model was then utilized to bring the data from ellipsoid heights to chart datum. North American Datum 1983 Projected UTM 17 Real-time positional data were corrected with G2+ GNSS satellite corrections provided by the Fugro Marinestar SBAS. A comparison was performed in CARIS HIPS between H13429 and the ENCs listed in Table 14 of section D.1.1. Sounding layers were generated from the CUBE surface and overlaid onto the ENCs to visually assess differences between the surveyed and charted depths. In addition to a detailed visual inspection in CARIS HIPS, all soundings from the chart were downloaded as a shapefile from NOAA's ENC Direct to GIS application and differenced with the nearest surveyed depth from H13429 in ESRI ArcPro. A statistical analysis of the difference comparison is shown in Figure 12. The surveyed depths from H13429 generally agree with the charted soundings from the largest scale ENCs within the survey area, with a mean difference of 1.54 m. Contour layers were generated from the CUBE surface and overlaid onto the ENCs to visually assess differences between the surveyed and charted contours. In H13429, the surveyed contours are in general agreement with the charted contours. Areas with larger discrepancies between the surveyed and charted contours are the result of the dynamic and irregular coral mounds rising from the seafloor. H13429 statistical analysis of surveyed depths to charted depths SupportFiles\ENC_Soundings_Histogram_H13429.png US5FL94M 10000 24 2021-08-23 2021-08-23 US5FL93M 30000 28 2021-08-05 2021-08-05 US5FL99M 40000 9 2021-08-04 2021-08-04 One Danger to Navigation (DtoN) was reported in H13429 and added to the FFF with Special Feature Type as 'DTON'. Refer to the FFF for the remarks and recommendations for each feature. See DR Appendix II Supplemental Records for the submitted DtoN report and related correspondence with the HSD Project Manager. It should be noted that the least depth and position changed slightly for the reported DtoN after the data were further post-processed. There were 18 assigned charted features within H13429 and are detailed in the FFF in accordance with section 7.3 of the HSSD. There were two assigned features with Special Feature Type as 'Unverified Charted Feature' that were investigated during survey operations, one of these assigned features was disproved, all of which are detailed as such in the FFF. There were 22 new features found within H13429 and are detailed in the FFF in accordance with section 7.3 of the HSSD. New area obstruction features representing navigationally significant coral mounds are detailed in the FFF with both the NATSUR and NATQUA attributes populated, as guided by the HSD Project Manager. See DR Appendix II Supplemental Records for related correspondence with the HSD Project Manager. 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. There were seven uncharted buoys that were observed during survey operations and reported through the Marine Chart Division's ASSIST customer service chart system per HSSD 1.6.2.2. See DR Appendix II Supplemental Records for the reports submitted via ASSIST and all related correspondence with the HSD Project Manager and Navigation Manager. All Aids to Navigation within the survey area are detailed in the FFF in accordance with section 7.3.6 of the HSSD. No Maritime Boundary Points were assigned for this survey. No bottom samples were required for this survey. No overhead features exist for this survey. There were six assigned submerged cables within H13429. In the northwest area of H13429, the multibeam data revealed bottom features potentially corresponding to the nearby charted submerged cable, as shown below in Figure 13. Other similar bottom features are visible throughout the multibeam data, although none were deemed navigationally significant. The assigned submerged cables were not included in the FFF in accordance with the Investigation Requirements listed in the Composite Source File (CSF). Bottom features potentially corresponding to charted cable SupportFiles\Submerged_Cable_H13429.png No platforms exist for this survey. No ferry routes or terminals exist for this survey. No abnormal seafloor 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 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 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 in the Descriptive Report. David J. Bernstein Chief of Party 2021-09-30 Data Acquisition and Processing Report 2021-09-30 Horizontal and Vertical Control Report 2021-09-30 Coast Pilot Report 2021-09-10