OPR-J311-KR-18Chandeleur - OffshoreChandeleur IslandsLeidosH13134225 NM SE of Chandeleur SoundLouisianaUnited States400002018Alex T. BernierBasic Hydrographic Survey2018-06-122018-08-222018-11-06Multibeam Echo SounderSide Scan SonarMultibeam Echo Sounder BackscattermetersUTCAtlantic Hydrographic BranchContract: EA-133C-14-CQ-0033/TO-0004.
Contractor: Leidos, 221 Third Street, Newport, RI 02840 USA.
Subcontractors: Divemasters, Inc., 15 Pumpshire Road, Toms River, NJ 08753; OARS, 8705 Shoal Creek Blvd, Suite 109, Austin, TX 78757.
Leidos Doc. 19-TR-004.
All times were recorded in UTC.
Data were collected in UTM Zone 16N.
ContractorThe area surveyed was a section of the Gulf of Mexico east of the Chandeleur Islands in LA (Figure 1). H13134 consisted of two combined areas from the Project Instructions; H13134 and H13134_ext. During survey operations, Leidos was instructed to complete additional data collection within the bounds of H13134_ext. As the extension sheet was listed as being associated with H13134 in the Project Instructions; Leidos merged the datasets into a single delivery. Throughout this Descriptive Report and supplemental data files, H13134 and H1334_ext are referred to as H13134.29.783725088.69886629.542946088.576083
H13134 Survey Bounds
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Survey limits were acquired in accordance with the requirements in the Project Instructions and the Hydrographic Surveys Specifications and Deliverables (HSSD).The purpose of this survey is to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products. The Chandeleur Offshore survey occupies 105 SNM through active oil and gas exploration areas and future state-leasing waters and is designated for further petroleum exploration and production. Located immediately outside of Louisiana’s main traffic fairway and Mississippi Entrance Channel, Chandeleur Offshore is in an area of extremely high vessel traffic while supporting one of the oldest and largest offshore hydrocarbon producing regions in the world. Oil and Gas is a leading industry in Louisiana. The total direct and indirect impact on the state is approximately $73.8 billion: direct impact coming from taxes, royalties, and fees; the indirect impact results from the salaries and wages earned by oil and gas employees and service companies doing business with oil and gas companies. This area was last surveyed by the Office of Coast Survey in 1922 and 1940. The central Gulf of Mexico is regularly impacted by severe storms and numerous dangerous hazards have been reported from damaged or destroyed drilling rigs, platforms, and seafloor pipelines. The quality of the bathymetry in the area indicates a 50 to 100 point gap in the risk based model between a healthy bathymetry safe for navigation and a high risk under keel clearance. The depths of the project area are shoaler than 20 fathoms. This survey will identify hazards and changes in bathymetry, providing contemporary data to update National Ocean Service (NOS) nautical charting products.The entire survey is adequate to supersede previous data.Leidos warrants only that the survey data acquired by Leidos and delivered to NOAA under Contract EA-133C-14-CQ-0033 reflects the state of the sea floor in existence on the day and at the time the survey was conducted.
H13134 was surveyed in accordance with the following documents:
1. Project Instructions, OPR-J311-KR-18, dated 12 June 2018
2. Hydrographic Surveys Specifications and Deliverables (HSSD), April 2018
3. OPR-J311-KR-18 Statement of Work, dated 14 June 2018All waters in survey areaComplete Coverage (Refer to HSSD Section 5.2.2.3)All waters in survey areaAcquire backscatter data during all multibeam data acquisition (Refer to HSSD Section 6.2)All waters in survey areaLNM no less than 2816 LNM. Report significant shoaling via weekly progress report. COR may adjust survey prioritization based on observed shoalingLeidos chose to achieve the coverage requirement using Complete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam). Survey coverage achieved was in accordance with the requirements in the Project Instructions and the HSSD (Figure 2, Figure 3, and Figure 4).
Final Bathymetry All Coverage for H13134 (at One-Meter Grid Resolution)
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Final Bathymetry One-Meter Coverage for H13134
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Final Bathymetry Two-Meter Coverage for H13134
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M/V Atlantic Surveyor00000748.99040.71000000748.99040.7105.444000402018-08-222018-08-232018-08-242018-08-252018-08-262018-10-012018-10-022018-10-042018-10-052018-10-062018-10-072018-10-132018-10-142018-10-312018-11-06Leidos used their ISS-2000 software on a Windows 7 platform to acquire these survey data. Survey planning and data analysis were conducted using the Leidos SABER software on Red Hat Enterprise 6 Linux platforms. Klein 3000 side scan sonar (SSS) data were collected on a Windows 7 platform using Klein’s SonarPro software. Subsequent processing and review of the SSS data, including the generation of coverage mosaics, were accomplished using SABER.
A detailed description of the systems and vessel used to acquire and process these data is included in the Data Acquisition and Processing Report (DAPR) for OPR-J311-KR-18, delivered concurrently with Descriptive Report H13133. There were no variations from the equipment configuration described in the DAPR.M/V Atlantic Surveyor1109
M/V Atlantic Surveyor
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The M/V Atlantic Surveyor (Figure 5) was used to collect multibeam echo sounder (MBES) (RESON SeaBat T50), side scan sonar (SSS) (Klein 3000), and sound speed data during twenty-four hours per day survey operations.
A detailed description of the vessels used is included in Section A of the DAPR.Teledyne RESON (RESON)SeaBat T50MBESKlein Marine Systems, Inc. (Klein)3000SSSApplanixPOS/MV 320 V5Positioning and Attitude SystemTrimbleProbeaconPositioning SystemAML OceanographicMVP30Sound Speed SystemA detailed description of the equipment installed is included in Section A of the DAPR.For specific details on the use and application of the SABER Total Propagated Uncertainty (TPU) model, see Section B.2 in the DAPR. Once the TPU model was applied to the GSF bathymetry data, each beam was attributed with the horizontal uncertainty and the vertical uncertainty at the 95% confidence level. The vertical and horizontal uncertainty values, estimated by the TPU model for individual multibeam soundings, varied little across the dataset, tending to be most affected by beam angle. Individual soundings that had vertical and horizontal uncertainty values above IHO S-44 5th Edition, Order 1a were flagged as invalid during the uncertainty attribution.
As discussed in Section B.2 of the DAPR, SABER generates two vertical uncertainty surfaces; the Hypothesis Standard Deviation (Hyp. StdDev) and the Hypothesis Average Total Propagated Uncertainty (Hyp. AvgTPU). A third vertical uncertainty surface is generated from the larger value of these two uncertainties at each node and is referred to as the Hypothesis Final Uncertainty (Hyp. Final Uncertainty).
The final H13134 one-meter PFM CUBE surface contained final vertical uncertainties that ranged from 0.224 to 0.528 meters. The IHO Order 1a maximum allowable vertical uncertainty was calculated to range between 0.536 to 0.564 meters, based on the minimum CUBE depth (14.794 meters) and maximum CUBE depth (20.000 meters). The SABER Check PFM Uncertainty function was used to highlight all instances in the Hyp. Final Uncertainty surface where a given node exceeded the IHO Order 1a allowable vertical uncertainty for the CUBE depth at that node. There were no nodes in the final H13134 one-meter PFM CUBE surface with final vertical uncertainties that exceeded IHO Order 1a allowable vertical uncertainty. The SABER Frequency Distribution Tool was also used to review the Hyp. Final Uncertainty surface within this final H13134 one-meter PFM grid, and the results showed that 100.00% of all nodes had final uncertainties less than or equal to 0.564 meters.
The final H13134 two-meter PFM CUBE surface contained final vertical uncertainties that ranged from 0.230 to 0.569 meters. The IHO Order 1a maximum allowable vertical uncertainty was calculated to range between 0.552 to 0.591 meters, based on the minimum CUBE depth (18.000 meters) and maximum CUBE depth (24.246 meters). Results from the SABER Check PFM Uncertainty function identified that there were no nodes in the final H13134 two-meter PFM CUBE surface with final vertical uncertainties that exceeded IHO Order 1a allowable vertical uncertainty. The SABER Frequency Distribution Tool was also used to review the Hyp. Final Uncertainty surface within the final H13134 two-meter PFM grid, and the results showed that in the final two-meter PFM grid, 100.00% of all nodes had final uncertainties less than or equal to 0.591 meters.
The H13134 one-meter PFM CUBE surface generated with all data (all valid depths of the survey area gridded at a one-meter node resolution, see Section B.5.2 for details) contained final vertical uncertainties that ranged from 0.224 to 1.239 meters. The IHO Order 1a maximum allowable vertical uncertainty was calculated to range between 0.536 to 0.596 meters, based on the minimum CUBE depth (14.794 meters) and maximum CUBE depth (24.913 meters). The SABER Check PFM Uncertainty function found that the H13134 one-meter PFM CUBE surface contained 32 CUBE nodes with final vertical uncertainties that exceeded IHO Order 1a allowable vertical uncertainty all of which were associated with depressions and discrete sediment mounds. The SABER Frequency Distribution Tool was also used to review the Hyp. Final Uncertainty surface within this final H13134 one-meter PFM grid, and the results showed that 99.99% of all nodes had final uncertainties less than or equal to 0.596 meters with 24 nodes exceeding 0.590 meters.Refer to Separates II for details about how the crossing analyses were performed and a complete discussion of each analysis and tabular results. Figure 6 summarizes the crossline comparison results.
Summary of Crossing Analysis
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As requested in the Project Instructions, analyses of the H13134 junctions with specified prior surveys were performed. Figure 7 shows the general locality of H13134 as it relates to the sheets to which junctions were performed. Details for each survey are listed in Table 7. Junction comparisons to surveys H12925, H12953, and H13133 were performed against the final respective BAG file or PFM grid for each sheet. Note that analysis of the junctions with sheet H13135 was not conducted, as processing efforts for that sheet were still ongoing. Refer to Separates II for details about how the junction analyses were performed and a complete discussion of each analysis and tabular results.
General Locality of H13134 with Junctioning Surveys
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H12925400002016David Evans & Associates, Inc.WH13134 junctions with H12925 to the west; 100.00% of the comparisons agreed within ±0.875 meters.H12953400002016David Evans & Associates, Inc.NWH13134 junctions with H12953 to the northwest; 100.00% of the comparisons agreed within ±0.926 meters.H13133400002018LeidosSWH13134 junctions with H13133 to the southwest; 100.00% of the comparisons agreed within ±0.300 meters.Sonar system quality control checks were conducted as detailed in Section A.5 of the DAPR.None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.None ExistThere were no factors affecting the soundings within H13134.On the M/V Atlantic Surveyor, the MVP30 was used to collect sound speed profile (SSP) data. SSP data were obtained at intervals frequent enough to meet depth accuracy requirements. Section 5.2.3.3 of the HSSD requires that if the sound speed measured at the sonar head differs by more than two meters/second from the commensurate profile data, then another cast shall be acquired. There were times when the sound speed values exceeded the two meters/second threshold due to the local temporal and tidal variability. During these times, several profiles were acquired and reapplied in an effort to reduce these effects. The product of this effort resulted in the final data bearing no significant artifacts due to sound speed differences.
All sound speed profiles applied for online bathymetry data collection were acquired within 250 meters of the bounds of the survey area as specified in Section 5.2.3.3 of the HSSD. Please refer to the DAPR for specific details regarding acquisition (Section A.7) and application (Section C.1.3) of sound speed profiles.
During multibeam acquisition, SSP casts were uploaded to ISS-2000 immediately after they were taken. In ISS-2000, the profiles were reviewed for quality, edited as necessary, compared to the preceding casts, and then applied (loaded into the multibeam system for use). Once applied, the multibeam system used the SSP data for depth calculation and ray tracing corrections to the multibeam data. If sounding depths exceeded the cast depth, ISS-2000 used the deepest sound speed value of the profile to extend the profile to the maximum depth. Similarly, during application of an acquired profile ISS-2000 extended the first profile depth up to zero meters, and also inserted the sound speed value from the sensor collocated with the MBES system into the appropriate depth, based on draft of the system, of the profile data.
Confidence checks of the sound speed profile casts were conducted by comparing at least two consecutive casts taken with different SSP sensors. Seven sound speed confidence checks were conducted during H13134 and the results can be found in Separates II within the “Comparison Cast Log” section.
All individual SSP files are delivered with the H13134 data and are broken out into sub-folders, which correspond to the purpose of each cast. Also, all individual SSP files for H13134 have been concatenated into four separate files based on the purpose of the cast, provided in CARIS format files (.svp), and delivered under (H13134/Processed/SVP/CARIS_SSP) on the delivery drive. In addition, sound speed data for the entire OPR-J311-KR-18 project will be submitted to NCEI following the NetCDF template format as specified in Section 8.3.6 of the HSSD.All equipment and survey methods are detailed in the DAPR.Multibeam Coverage AnalysisLeidos chose to achieve the coverage requirement using 100% side scan sonar coverage with concurrent multibeam bathymetry. To achieve this coverage, the M/V Atlantic Surveyor used a towed Klein 3000 SSS set to either 75-meter or 50-meter range scales. Mainscheme line spacing was 130 meters and 80 meters respectively, which ensured 100% SSS coverage.
The HSSD stated that 100% SSS coverage was insufficient to disprove a charted feature. Therefore, Leidos reviewed the Composite Source File (CSF), BSB charts, and ENC charts and completed an additional 100% SSS coverage, and resulting MBES coverage over charted objects not found during survey in order to verify disproval in accordance with Section 7.3.4 in the HSSD. A disproval search radius was developed as specified in the Project Instructions dated 12 June 2018. For all charted objects within the assigned Survey Limits of H13134, each object’s disproval data covered an area of at least the assigned disproval search radius.
The SABER Gapchecker program was used to flag MBES data gaps within the CUBE surface. Additionally, the entire surface was visually scanned for holidays at various points during the data processing effort. Additional survey lines were run to fill any holidays that were detected. A final review of the CUBE Depth surface of the H13134 one-meter PFM containing all MBES data, the one-meter PFM containing data from 14.794 meters to 20.000 meters, and the two-meter PFM containing data from 18.000 meters to 24.913 meters showed that there were no three by three node gaps.
The final H13134 CUBE PFM was examined for the number of soundings contributing to the chosen CUBE hypotheses for each node by running SABER’s Frequency Distribution Tool on the Hypothesis Number of Soundings (Hyp. # Soundings) surface. The Hyp. # Soundings surface reports the number of soundings that were used to compute the chosen hypothesis. Analysis of the H13134 Hyp. # Soundings surface of the H13134 one-meter PFM containing all MBES data, the one-meter PFM containing data from 14.794 meters to 20.000 meters, and the two-meter PFM containing data from 18.000 meters to 24.913 meters revealed that 99.43%, 98.69%, and 99.59% of all nodes contained five or more soundings respectively; satisfying the requirements for complete coverage surveys, Option B, as specified in Section 5.2.2.3 of the HSSD.All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.2018-08-22Side Scan Sonar (SSS) Coverage Analysis: As previously detailed in Section B.2.9, Leidos chose to achieve the coverage requirement using 100% side scan sonar coverage with concurrent multibeam bathymetry. To achieve this coverage, the M/V Atlantic Surveyor used a towed Klein 3000 SSS set to either 75-meter or 50-meter range scales. Mainscheme line spacing was 130 meters and 80 meters respectively, which ensured 100% SSS coverage. The SSS range scale was set to 75-meter range during acquisition for all of the main H13134 survey area, however, the H13134_ext survey area was acquired with an SSS range scale of 50-meters. While the H13134_ext area was originally planned with line spacing for 75-meter range scale SSS acquisition, this was changed to 50-range scale line spacing after the initial survey lines collected in this area showed a more prevalent thermocline and surface noise in the outer ranges of the 75-meter SSS data acquired at that time. To minimize any data gaps and improve data quality, the line spacing for this area was adjusted to 50-meter SSS range scale acquisition. Any SSS data acquired in the H13134_ext at 75-meter range and included in the final SSS mosaic surfaces were deemed acceptable and were also clipped to the 50-meter range during the SABER mosaic generation process.
For all details regarding SSS data processing, see Section B.3 of the DAPR. Leidos chose to adhere to the coverage requirements in the Project Instructions using Complete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam). The HSSD stated that 100% SSS coverage was insufficient to disprove a charted feature. Therefore, 100% SSS coverage was collected and verified for the entire survey area, and an additional 100% SSS coverage was collected over CSF assigned objects, and charted objects that were not found, to verify disproval. Leidos generated two separate coverage mosaics at one-meter cell size resolution as specified in Section 8.2.1 of the HSSD. The first 100% and second 100% disproval coverage mosaics were independently reviewed using tools in SABER to verify data quality and swath coverage. The SABER Gapchecker routine was used to flag data gaps within each of the 100% SSS coverage mosaics. Additionally, the entirety of each SSS surface was visually scanned for holidays at various points during the data processing effort. Additional survey lines were run to fill any holidays that were detected. Both coverage mosaics are determined to be complete and sufficient to meet the requirements contained within the Project Instructions and HSSD. The mosaics are delivered as TIFF (.tif) images with accompanying world files (.tfw), refer to Table 10.
Multibeam Echo Sounder Seafloor Backscatter: In accordance with the HSSD and Project Instructions, Leidos collected MBES backscatter with all GSF data acquired by the RESON SeaBat T50. The MBES settings used were checked to ensure acceptable quality standards were met and to avoid any acoustic saturation of the backscatter data. The MBES backscatter data acquired were written to the GSF in real-time by ISS-2000 and are delivered in the final GSF files for this sheet. Per the Project Instructions, backscatter data were not processed by Leidos and no additional products were produced.LeidosSABER5.4.0.10.2LeidosSABER5.4.0.10.1NOAA Extended Attribute File V5-4The primary data processing software used for both bathymetry and imagery was SABER. The SABER version for bathymetric data processing differs from the version noted in the DAPR submitted with H13133.H13134_MB_1m_MLLW_Final_1of3.bagBAG114.79420.000N/AComplete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam)H13134_MB_1m_MLLW_Final_2of3.bagBAG115.89720.000N/AComplete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam)H13134_MB_1m_MLLW_Final_3of3.bagBAG116.44820.000N/AComplete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam)H13134_MB_2m_MLLW_Final.bagBAG218.00024.246N/AComplete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam)H13134_MB_MLLW_Final_All_Data_1m_1of3.bagBAG114.79423.857N/AComplete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam)H13134_MB_MLLW_Final_All_Data_1m_2of3.bagBAG115.89724.913N/AComplete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam)H13134_MB_MLLW_Final_All_Data_1m_3of3.bagBAG116.44822.974N/AComplete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam)H13134_SSSAB_1m_100kHz_1of2SSS Mosaic (.tif;.tfw)100N/A100% SSSH13134_SSSAB_1m_100kHz_2of2SSS Mosaic (.tif;.tfw)100N/A200% SSS Charted Object DisprovalComplete Coverage Section 5.2.2.3 of the HSSD requires one-meter node resolution for depths ranging from zero meters to 20 meters, and two-meter node resolution for depths ranging from 18 meters to 40 meters. Leidos generated CUBE PFM grids for H13134 at one-meter and two-meter resolutions with the specified depth range for each, and used these surfaces to assess and document multibeam survey coverage for their respective depth ranges. SABER populates the CUBE depth with either the node’s chosen hypothesis or the depth of a feature or designated sounding set by the hydrographer, which overrides the chosen hypothesis. The range of CUBE depths of the H13134 one-meter and two-meter CUBE PFM grids were from 14.794 meters (48.537 feet; 0.230 meters Total Vertical Uncertainty [TVU]) to 20.000 meters (65.617 feet; 0.240 meters TVU), and 18.000 meters (59.055 feet; 0.230 meters TVU) to 24.246 meters (79.547 feet; 0.235 meters TVU) respectively.
During evaluation of the one-meter (0.0m-20m depths) and two-meter (18m-40m depths) CUBE PFM Depth surfaces, Leidos concluded that as a result of the specified depth cutoffs the surveyed depths were not being honored properly within the final CUBE surfaces in areas of overlapping depth criteria; such as around seafloor depressions. Due to this, Leidos generated an additional CUBE PFM grid which included all valid depth data for H13134, at a one-meter grid resolution. The range of CUBE depths of the additional H13134 one-meter CUBE depth surface, containing all MBES depth data from H13134, from 14.794 meters (48.537 feet; 0.230 meters TVU) to 24.913 meters (81.736 feet; 0.355 meters TVU). Analyses of the additional H13134 one-meter CUBE depth surface, containing all MBES depth data from H13134, were conducted and the results are presented throughout this DR alongside the results from the same analyses done of the one-meter (0.0m-20m depths) and two-meter (18m-40m depths) CUBE PFM surfaces. Based on all results it was determined that the data support the generation of a one-meter grid resolution surface for areas deeper than 20 meters within H13134.
Due to the government shutdown Leidos was unable to discuss their findings and therefore chose to submit the additional surface which included all depths of the survey area gridded at a one-meter node resolution.
The final gridded bathymetry data are delivered as a Bathymetric Attributed Grid (BAG). The BAG files were exported from the CUBE PFM grid as detailed in Section B.1.8 of the DAPR.Additional information discussing the vertical and horizontal control for this survey can be found in the OPR-J311-KR-18 DAPR.Mean Lower Low WaterTCARI1970-01-011970-01-01ERS via Poor Mans VDATUMOPR-J311-KR-18_NAD83_PMVD_MLLW.covA Poor Man’s Vertical Datum (PMVD) separation model was used to transform the multibeam data to Mean Lower Low Water (MLLW). Refer to the DAPR for details on the generation and application of the PMVD; also Appendix II of H13134; the Vertical Control Memo. As the PMVD was used for the final datum transformation, per the Project Instructions the requirement to request TCARI Final Solutions was waived for OPR-J311-KR-18. Therefore no final tide note was provided from NOAA Center for Operational Oceanographic Products and Services (CO-OPS). While a final tide note was not required, a final tide note has been provided by Leidos in Appendix I.North American Datum of 1983 (NAD83) 2011 realization 2010 (NAD83(2011)2010.0)UTM Zone 16, NorthSingle BaseApplanix POSPac software was used to post-process the vessel kinematic data (POS/MV files) and used the Applanix PP-RTX solution for post-processing to generate the Smoothed Best Estimate of Trajectory (SBET) solutions which were applied through SABER to the multibeam data. Refer to the DAPR for additional information and for details regarding all antenna and transducer offsets.
Any soundings with total horizontal uncertainties exceeding the maximum allowable IHO S-44 5th Edition Order 1a specifications were flagged as invalid and therefore were not used in the CUBE depth calculations.The chart comparisons were conducted using a combination of SABER and CARIS’ HIPS and SIPS.
United States Coast Guard (USCG) District 8 Local Notice to Mariners (LNMs) publications were reviewed for changes subsequent to the date of the Project Instructions prior to the start of survey operations, and continued to be reviewed through the end of survey (as specified in Section 8.1.4 of the HSSD). The LNMs reviewed were from week 34/18 (22 August 2018) until week 45/18 (07 November 2018) during survey operations. Additional LNMs reviewed after completing acquisition and during post processing are discussed in Section D.2.3.
H13134 data met data accuracy standards and bottom coverage requirements. Recommend updating the common areas of all charts using data from this survey. Charting recommendations for all features found, and updates to charted features, are documented in the H13134 S-57 FFF. Additional charted objects such as submarine pipelines and platforms are discussed in later sections.US4LA34M80000352018-11-29false2018-10-23ENC US4LA34M covers the H13134 survey area from 088° 40’ 30.17”W westward.
CUBE depths within H13134 were generally deeper than charted depths across the survey area, with observed depths approximately 1.0m to 3.0m deeper than the charted depths (Figure 8). The 18.2-meter contour generally agrees with the depths from the H13134 survey (Figure 9).
ENC US4LA34M with CUBE Depth Selected Soundings (red) Approximately 1-3 Meters Deeper than Charted
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ENC US4LA34M with Charted 18.2 Meter Contour and CUBE Depths Greater than 18.0 Meters from the H13134 Survey
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US3GC04M250000622018-01-02false2018-12-20ENC US3GC04M covers the H13134 survey area in its entirety.
There were three charted depths covered by the H13134 survey. The CUBE depths were approximately 0.5 to 2 meters deeper than the charted depths. The charted 18.2 meter contour is generally adequate for the scale of the chart in the southern part of the survey area however in the northern area, the 18.2-meter depth contour was found to be quite different (Figure 10). The 18.2-meter depth contour as depicted in ENC US4LA34M more closely agrees with the depths from H13134 survey.
ENC US3GC04M with Charted 18.2 Meter Contour and CUBE Depths Greater than 18.0 Meters from the H13134 Survey
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No Maritime Boundary Points were assigned for this survey.One charted obstruction, a wellhead with a depth of 9.1 meters, was charted on ENC US4LA34M and US3GC04M within the survey bounds. The area was covered with 200 percent SSS and resulting MBES over an area with a radius of at least 50 meters. No feature was found within the search radius. See the H13134 S-57 FFF for all the details and recommendations regarding this feature.See the H13134 S-57 FFF for all the details and recommendations regarding new uncharted features investigated.There were no significant shoals or hazardous features within the area covered by this survey other than those discussed in Section D.1.4.A section of the two-way safety fairway approximately 42km north of the Mississippi River Gulf Outlet was covered by the H13134 survey. Nothing of note was identified during the survey.In accordance with both the Project Instructions and Section 7.2.3 of the HSSD, bottom characteristics were obtained for H13134. Bottom characteristics were acquired at the four locations assigned in the Project Reference File (PRF) by NOAA. Leidos did not modify the bottom sample locations from the location proposed by NOAA in the PRF. Bottom characteristics collected during H13134 are included in the H13134 S-57 FFF, named H13134_FFF.000, within the Seabed Area (SBDARE) object, and are classified according to the requirements set forth in Appendix H of the HSSD. In addition, still images of the sediment obtained for each bottom sample, short videos of the seafloor at each bottom sample location, and a still image of the seafloor are referenced in the H13134_FFF.000 and are included on the delivery drive under the folder H13134/Processed/Multimedia.All features in the CSF within the assigned Survey Limits of H13134 were resolved. There were no assigned features inshore of the NALL.Junction analysis with prior surveys H12925 and H12953 (both collected in 2016) were conducted and the results are presented in Section B.2.3 of this Descriptive Report and within Separates II.There was one private Aid to Navigation (ATON) assigned in the final CSF that fell within this survey area.
This ATON is number 350 on the USCG LIGHT LIST, Volume IV, GULF OF MEXICO, and is described as a red buoy, Mobil-194-6 Lighted Horn Buoy, Marks subsea installation, Quick Red, SIGN: MO-MP-99-1, HORN: 1 blast ev 20s (2s bl), Private aid. In the USCG Light List, this ATON is listed on RNC 11360, however, the ATON is not depicted on this chart. This ATON is charted on RNC 11363, as well as ENC US3GC04M, and ENC US4LA34M.
The area was covered with 200 percent SSS and resulting MBES over an area with a radius of at least 80 meters. No ATON was found within the search radius, and no pipeline subsea installations or other underwater hazards to navigation were found in the SSS or MBES data within the search radius covering the position of this ATON.
In accordance with HSSD Section 1.6.2.2, the missing ATON was reported to the USCG using the USCG Navigation Center’s Online ATON Discrepancy Report Form. Starting on week 51/18 (December 19, 2018) the USCG District 8 Local Notice to Mariners (LNMs) have listed this ATON as a discrepancy with a status of: MISSING. The LNMs have been reviewed through the most current release (week 04/19) during finalization of this DR, which still lists the ATON status as: MISSING.
See the H13134 S-57 FFF for all the details and recommendations regarding this feature. A PDF copy of the report submitted to the USCG Navigation Center (printer friendly version) as well as the email correspondence regarding the ATON Discrepancy Report submission, are included Appendix II of this DR.There were no overhead features within this survey area.Thirteen exposed pipelines were found within the bounds of H13134. In accordance with HSSD Section 1.7, the exposed pipelines found within H13134 were submitted as a Non-DTON Pipeline Report. The email correspondence for Leidos’ submission of the H13134 Non-DTON Pipeline Report is included within Appendix II of this Descriptive Report. In accordance with HSSD Section 1.7, the identified exposed pipelines are not included in the S-57 FFF. PIPSOL objects delivered in the CSF are captured in the S-57 FFF.There were five offshore platform objects in the CSF, 2018_0621_OPR-J311-KR-18_CSF_Final.000, provided on 27 June 2018, which fell within the Survey Limits of H13134. Four of these objects were assigned, the fifth offshore platform was unassigned in the final CSF, as it fell within the bounds of the H13134_ext area. During data acquisition; Leidos treated this platform as if it were assigned. One of the assigned platforms was charted on ENC US4LA34M and Raster 11363, and four of the assigned platforms were charted on ENC US3GC04M and Raster 11366. Of the five charted platforms assigned within the survey area for H13134, two platforms were visible above the waterline. The remaining three assigned charted platforms were not found during survey operations so disproval surveys were conducted. The charted platforms were covered by 200% SSS and resulting MBES over an area with a radius of at least 80 meters. There was no evidence of the platforms existence in the side scan or multibeam data. See the S-57 FFF, H13134_FFF.000, Offshore Platform (OFSPLF) objects, for details and charting recommendations for the charted platform.No ferry routes or terminals exist within this survey area.No abnormal seafloor or environmental conditions, as defined in Section 8.1.4 of the HSSD, exist within this survey area other than those discussed in Section D.1.4.No construction or dredging exists for this survey area.Designated SoundingsSeparate flags exist in the Generic Sensor Format for designated soundings and features. Designated soundings or feature flags were used to help better preserve the shallowest sounding relative to the computed depth surface. All depths flagged as features and designated soundings override the CUBE best estimate of the depth in the final BAG files. Both the designated sounding and feature flags, as defined within GSF, are mapped to the same HDCS flag when ingested into CARIS (PD_DEPTH_DESIGNATED_MASK).
No GSF designated sounding flags or feature flags were set for H13134.Final Feature S-57 FileIncluded with H13134 delivery is the S-57 FFF, H13134_FFF.000. Details on how this file was generated and quality controlled can be found in Section B.1.9 of the DAPR. The S-57 FFF delivered for H13134 contains millimeter precision for the value of sounding (VALSOU) attribute. As specified in Section 2.2 of the HSSD, the S-57 FFF is in the WGS84 datum and is unprojected with all depth units in meters. All significant, and recommended for charting, features found in H13134 are included within the S-57 FFF.
In accordance with the HSSD, Leidos addressed all assigned objects within the bounds of H13134 from the provided CSF S-57 file in the S-57 FFF.
For each feature contained in the FFF (S-57), the Feature Correlator Sheet was exported as an image file (.jpg) and is included in the S-57 FFF under the NOAA Extended Attribute field “images”.Side Scan Sonar Contacts S-57 FileIncluded with the H13134 delivery is the Side Scan Sonar Contact S-57 File, H13134_SSCon.000. Details on how this file was generated and quality controlled can be found in Section B.3.5 of the DAPR. As specified in Section 2.2 of the HSSD, the S-57 file is in the WGS84 datum and is unprojected with all depth units in meters.
Side scan sonar contacts were investigated and confirmed using SABER Contact Review. All side scan contacts are retained within the Side Scan Sonar Contact S-57 File. For each contact included in this S-57 file, a JPEG image of the side scan contact is included under the NOAA Extended Attribute field “images”.Coast Pilot Review ReportIn accordance with the Project Instructions and HSSD Section 8.1.3, a Coast Pilot Review was performed for OPR-J311-KR-18. Within the Coast Pilot Field Report (OPR-J311-KR-18CoastPilotReview.pdf) provided by NOAA to Leidos on 27 June 2018, there were no assigned investigation items or paragraphs affected. Therefore, Leidos reviewed and updated the actual Coast Pilot paragraphs as possible for the survey areas, port of call, and areas frequently transited. Updates were made to the Coast Pilot paragraphs as defined in the HSSD Section 8.1.3 and incorporated in to a consolidated Coast Pilot Review Report (OPR-J311-KR-18_Coast Pilot Review Report.pdf) which was submitted to NOAA on 18 December 2018. The email correspondence for Leidos’ submission of the H13134 Coast Pilot Review Report is included within Appendix II of this Descriptive Report.No new survey recommendations are made for the area surrounding this survey area.No inset recommendations are made for the area covered by this survey.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 BAG files, 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 Hydrographic Surveys Specifications and Deliverables, Project Instructions, and Statement of Work. 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. Previously, or concurrently, submitted deliverables for OPR-J311-KR-18 are provided in the table below.Alex T. BernierLead Hydrographer2019-02-04OPR-J311-KR-18_Marine_Species_Awareness_Training_Record.pdf2018-12-19OPR-J311-KR-18_Coast Pilot Review Report.pdf2018-12-19OPR-J311-KR-18_Marine_Mammal_Observation_Log.pdf2019-01-17OPR-J311-KR-18_Sea_Turtle_Observation_Log.pdf2019-01-17OPR-J311-KR-18_DAPR.pdf2019-01-22H13133_DR.pdf2019-01-22H13133_DR_rev1.pdf2019-02-04