OPR-K339-KR-16 Offshore SW Pass Gulf of Mexico eTrac Inc. H12946 6 Acquire assigned crossline lines and investigate assigned features. 7 NM Southwest of Port Fourchon Louisiana United States 20000 2016 David Neff, ACSM C.H. Basic Hydrographic Survey 2016-06-29 2016-09-10 2016-09-11 Multibeam Echo Sounder Multibeam Echo Sounder Backscatter meters Universal Transverse Mercator (UTM) UTC Atlantic Hydrographic Branch Registry Instructions: Acquire assigned crossline lines and investigate assigned features. All times are UTC. The extents of H12946 designate a newly proposed anchorage area about 7 nautical miles southwest of Port Fourchon. The purpose of this resurvey is to detect any bathymetric or feature changes that may need to be addresses before the proposed anchorage area is approved and charted. SUBCONSULTANT: Geodynamics LLC, 310A Greenfield Dr., Newport, NC 98570 SUBCONSULTANT: Theory Marine, 777 Viewcrest DR., Ventura, CA 93003 Projections: UTM 15N, WGS 84 Contractor eTrac Inc. conducted hydrographic survey operations in the Gulf of Mexico. H12946 covers approximately 7 square nautical miles of survey area. 43 lineal nautical miles were aquired during the survey. H12946 is irregular in geometry, and is approximately 2 nautical miles wide (E-W) by 5 nautical miles long (N-S) at its widest and longest lengths respectively. Survey was conducted within these limits on the assigned lines between September 10, 2016 (DN254) and Spetember 11, 2016 (DN255). 29.032216 90.320920 28.950803 90.310747 Survey Limits (Black line) Assigned Lines (Blue) SUPPORTFILES/H12946_SHEETLIMITS.JPG Registry Instructions: Acuire assigned crosslines and investigate assigned features. All data were acquired in accordance with the requirements in the Project Instructions and specifications set forth in the Hydrographic Survey Specifications and Deliverables 2016 Edition (HSSD 2016). Survey was aquired along the assigned crossline and assigned features. The extents of H12946 designate a newly proposed anchorage area, about 7 nautical miles southwest of Port Fourchon. This port services the majority of the Gulf of Mexico's deep water oil production and has a high concentration of vessel traffic. This area was last surved in 2006 and 2009 to object detection coverage stantards. The purpose of this resurvey is to detect any bathymetric or feature changes that may need to be addressed before the proposed anchorage area is approved and charted. Survey was acquired along the assigned crossline lines and assigned features. The entire survey is adequate to supersede previous data. Survey H12946 is accurate to IHO Order 1a as required per the HSSD 2016. Survey Coverage was in accordance with the requirements in the Project Instructions and HSSD 2016. Depths in H12946 range from 9 to 18 meters. The assigned crosslines lines were acquired and the assigned features were investigated as stated in the Project Instructions. Survey Coverage SUPPORTFILES/H12946_SURVEY_COVERAGE.JPG Theory 0 46 0 0 0 0 0 5 0 0 46 0 0 0 0 0 5 0 10.86 3 0 0 0 0 7 2016-09-10 2016-09-11 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. M/V Theory 11 0.75 The M/V Theory is a 11 meter aluminum catamaran equipped with an Universal Sonar Mount (USM) over-the-stern multibean mount, as well as an A-frame for SVP deployment. R2Sonic 2024 MBES Applanix POSMV 320 V5 Positioning and Attitude System AML Base.X2 Sound Speed System Trimble DSM232 Positioning System A comparison of crossline mileage to mainscheme mileage yields a crossline percentage of 10.86%, and is noted to be above the required 8%. A beam-by-beam statistical analysis was performed using the Line QC reporting tool in Caris HIPS and SIPS 9.1. A 1 meter CUBE weighted BASE surface was created incorporating only the mainscheme and feature investigation lines, and excluded crosslines. The Line QC reporting 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: the statistical analysis excluded the outer 5 beams (beams 1-5 and beams 252-256), as these beams were excluded from both mainsheme and crossline data across the entire project. 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 Caris QC Reporting tool is included in Separate II. Below is a graph of crossline comparison statistics showing IHO Order 1a compliance per beam. H12946 Crossline Comparison (1m) SUPPORTFILES/H12946_CROSSLINE_COMPARISON.JPG M/V Theory 4 0 2 Note: The survey specific tide TPU values for measured and zoning tides are computed internally within TCARI. Standard deviation and uncertainty child layers of BASE surfaces were utilized during data processing to search for features, water column noise, and systematic errors. A custom child layer was created within the BASE surface utilizing the Deep and Shoal layers in the following configuration: Custom Layer = (Deep - Shoal)^2 By viewing this custom layer, seafloor features, water column noise, and systematic errors are graphically exaggerated and can easily be identified for further examination. A TVU QC layer was created within the BASE surface utilizing the Uncertainty and Depth child layers in the following configuration: -Uncertainty/((0.5^2 +((Depth*0.013)^2))^0.5) By viewing the TVU QC layer, nodes that exceed the IHO Order 1a uncertainty standards can be identified and further analyzed. Standard deviation and uncertainty were quantified using the QC Reporting tool within Caris HIPS and SIPS 9.1. The option "Greater of the two" was selected in the reporting tool in order to generate statistics quantifying the maximum error occurring within the data. IHO Order 1a uncertainty specification was met by 100% of the nodes. Each BASE surface's uncertainty QC report generated through the Caris QC Reporting tool is included in Separate II. The Total Propogated Uncertainty (TPU) was evaluated using the TPUTrac program in the AmiTrac program, developed in-house by eTrac Inc. The BASE surface's nodes were exported to an ASCII CSV file where the fields were (Easting, Northing, Depth, Uncertainty, Density) for each node. The CSV file was then loaded into the TPUTrac program and the TPU statistics were computed. A file was also created in this process to locate any points that exceed the allowable TPU, which was imported into Caris HIPS and SIPS 9.1 and any identified points from TPUTrac were analyzed and evaluated. For H12946 the following percentages represent the results of the TPU Testing: Assigned Crossline Lines and Features MBES (Finalized 1m CUBE weighted BASE Surface) = 100% of nodes are within allowable TPU. H12946 Finalized 1m Assigned Crossline Lines and Features MBES TPU Statistics SUPPORTFILES/H12946_TPUTRAC_1M_FINAL.JPG Depth differences between junctioning surveys were evaluated using the JunctionTrac program, developed in-house by eTrac Inc. For each junction, each BASE surface's nodes were exported to an ASCII CSV file where the fields were (Easting, Northing, Depth) for each node. A 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 Caris HIPS and SIPS 9.1 and any identified points from JunctionTrac were analyzed. Note: the difference surfaces were created for comparison efforts only and are not submitted as a surface deliverable. H12049 10000 2009 C & C Technologies, Inc. SW H12946 junctions with H12049 to the Southwest. The junction comparison was performed using approximately 2,700m of overlapping data between H12946 and H12049. Depth differences were evaluated using the JunctionTrac program, developed in-house by eTrac Inc. Below is a histogram of junction comparison statistics showing the difference between the junctioning surfaces and allowable TVU. 99.9859% of nodes were within allowable TVU. Survey H12946 and H12049 overlap a feature. The extreme outlier in the below graph is noted to be casued by this feature being represented slightly differently in the respective surfaces. Junction comparison statistics are also included in Separate II. H12946 - H12049 Junction Comparison SUPPORTFILES/H12946_H12049_JUNCTION.JPG H11785 20000 2009 Leidos NW H12946 junctions with H11785 to the North. The junction comparison was performed using approximately 2,700m of overlapping data between H12946 and H11785.Depth differences were evaluated using the JunctionTrac program, developed in-house by eTrac Inc. Below is a histogram of junction comparison statistics showing the difference between the junctioning surfaces and allowable TVU. 99.9967% of nodes were within allowable TVU. Survey H12946 and H11785 overlap a feature that was not found in survey H12946. The extreme outlier in the below graph is noted to be casued by this feature only being represented in H11785. Junction comparison statistics are also included in Separate II. H12946 - H11785 Junction Comparison SUPPORTFILES/H12946_H11785_JUNCTION.JPG H11457 20000 2006 C & C Technologies, Inc. SE H12946 junctions with H11457 to the East. The junction comparison was performed using approximately 1,300m of overlapping data between H12946 and H11457. Depth differences were evaluated using the JunctionTrac program, developed in-house by eTrac Inc. Below is a histogram of junction comparison statistics showing the difference between the junctioning surfaces and allowable TVU. 90.3640% of nodes were within allowable TVU. Survey H12946 and H11457 overlap a feature that was not found in survey H12946. The extreme outlier in the below graph is noted to be casued by this feature only being represented in H11457. Survey H11475 was aquired in 2006. The lower percentage is likely caused by the time period between the two surveys. Junction comparison statistics are also included in Separate II. H12946 - H11457 Junction Comparison SUPPORTFILES/H12946_H11457_JUNCTION.JPG 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. Ocassionally casts would exceed a 2 hour frequency, however would never exceed a 4 hour frequency. 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. SVP surface velocities were compared in realtime and profile to profile for each cast on the vessel. Additionally, profiles were compared day-to-day in the field office using the SVPTrac program, developed in-house by eTrac Inc., to better understand trends for efficient acquisition planning. Example of Day to Day SVP Comparison (DN254) SUPPORTFILES/H12946_SVP_TH_DN254.JPG Example of Day to Day SVP Comparison (DN254 & DN255) SUPPORTFILES/H12946_SVP_TH_DN254_DN255.JPG 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 the DensityTrac program in the AmiTrac program, developed in-house by eTrac Inc. Each finalized BASE surface's nodes were exported to an ASCII CSV file where the fields were (Easting, Northing, Depth, Uncertainty, Density) for each node. The CSV file was then loaded into the DensityTrac program and density statistics were computed. For H12946 the following percentages represent the results of the density testing: Assigned Crossline Lines and Features MBES (Finalized 1m CUBE weighted BASE Surface) = 99.1234% of nodes are composed from at least 5 soundings. H12946 Finalized 1m Assigned Crossline Lines and Features MBES Density Distribution Statistics SUPPORTFILES/H12946_DENSITYHISTOGRAM_1M_FINAL.JPG 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 XTF 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. engaged in a minimal effort to verify coverage and general quality of the backscatter data collected. Raw backscatter data were viewed in Caris HIPS and SIPS 9.1 to ensure collection criteria had been met. Shown below is an example of the unprocessed backscatter mosaic from H12946 DN255. Raw Backscatter From M/V Theory (DN255) SUPPORTFILES/H12946_BACKSCATTER_TH_DN255.JPG NOAA Profile V_5_4 H12946_MB_1m_MLLW_Final BAG 1 9.14 17.33 NOAA_1m Complete MBES H12946_MB_1m_MLLW BAG 1 10.21 17.33 NOAA_1m Complete MBES In areas shoaler than 20 meters, a 1m surface is provided meeting specifications set forth in the Project Instructions. The 1m surface covers the entire survery area of H12946 as all soundings within the survey limits are shoaler than 20 meters. A parent surface of the 1m surface is provided. The 1m parent surface covers the entire survey area of H12946. H12946 Delivered BASE Surface Coverage Graphic SUPPORTFILES/H12946_SURFACES_COVERAGE.JPG Mean Lower Low Water TCARI 8760922.tid Final Approved 8761724.tid Final Approved 8762075.tid Final Approved K339KR2016Final.tc Final 2016-09-20 2016-10-25 In order to reference soundings to MLLW, the Tidal Constituent And Residual Interpolator (TCARI) method was applied to the HDCS data via the TCARI program. TCARI compiled information from SW Pass, LA (8760922), Grand Isle, LA (8761724), and Port Fourchon, LA (8762075). Note: Any vertical control method deviations from the Project Instructions are addressed in the DAPR. World Geodetic System of 1984 (WGS84) UTM Zone 15N English Turn, 293kHz, ID: 814 During main acquisition M/V Theory received GNSS satellite corrections over the POS MV G2 carrier signal from the Marinestar Global Correction System maintained by Fugro. The Marinestar system is a global realtime GNSS broadcast system that delivers corrections from an array of base stations around the world via geo-stationary satellites. Corrections were monitored realtime during data acquisition to ensure no dropouts occurred and the POSMV maintained differential accuracies throughout the survey. No dropouts were witnessed during data collection. Position data were analyzed in the office during post-processing. The attitude editor within Caris HIPS and SIPS 9.1 was utilized to identify any position data that may be insufficient for final delivery. DGPS stations were only to be used as a backup horizontal correction source. G2 Marinestar correctors were used as the primary correction source. DGPS was never utilized, as G2 corrections were available throughout all survey operations A chart comparison was conducted for H12946 using Caris HIPS and SIPS 9.1. Soundings were compared against the largest scale RNC 11346 and ENC US5LA26M to accomplish the chart comparison. RNC 11346 and ENC US5LA26M do not cover the western half of H12946, and therefore RNC 11357 and ENC US4LA29M were included to complete the chart comparison. The methods and results of the comparison are detailed below. The methods and results of the comparison are detailed below. Contour Comparison Method: No contours are present in RNC 11346 and ENC US5LA26M or RNC 11346 and ENC US5LA26M, within the survey limits of H12946, therefore no contour comparisons were conducted. Sounding Comparison Method: Using the 1 meter CUBE weighted BASE surface, spot soundings were generated in Caris HIPS and SIPS 9.1 for H12946. Soundings were displayed against the charted soundings and a visual comparison was made. The results are described below. 11346 0 40000 5 2014-03 2016-05-18 2016-05-22 Sounding Comparison Results: In general, the soundings are in excellent agreement, with no major discrepencies. Soundings are generally within 1 foot of each other. Occasionally soundings differ by 2 to 3 feet, however depth differences generally appear to be minimal. Depth differences are not biased in any particular direction to support a systematic error. 11357 0 80000 43 2014-05 2016-06-07 2016-06-18 Sounding Comparison Results: In general, the soundings are in excellent agreement, with no major discrepencies. Soundings are generally within 1 foot of each other. Occasionally soundings differ by 2 to 3 feet, however depth differences generally appear to be minimal. Depth differences are not biased in any particular direction to support a systematic error. Sounding Comparison (RNC 11346) SUPPORTFILES/H12946_RNC11346_SOUNDINGCOMPARISON.JPG Sounding Comparison (RNC 11357) SUPPORTFILES/H12946_RNC11357_SOUNDINGCOMPARISON.JPG US5LA26M 40000 24 2014-07-15 2016-04-26 false The results of the chart comparison with ENC US5LA26M match those of the chart comparison with RNC 11346. US4LA29M 80000 19 2014-11-26 2016-04-25 false The results of the chart comparison with ENC US5LA29M match those of the chart comparison with RNC 11357. No AWOIS Items were assigned for this survey. No Maritime Boundary Points were assigned for this survey. There were 3 charted features assigned to H12946. Each 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 H12946_XXX). Refer to the FFF for determinations and recommendations of each feature. There was 1 new feature found in H12946 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 H12946_XXX). Refer to the FFF for determinations and recommendations of each feature. There were 2 uncharted features assigned to H12946. Each assigned feature is retained in the FFF. Each feature in the FFF has been given a unique identifier in the "userid" field of the .000 S-57 file (format H12946_XXX). Refer to the FFF for determinations and recommendations of each feature. Note: Both assigned, uncharted features are listed as BSEE Wellheads. There were no DTONs found in this survey. No shoals or potentially hazardous features exist for this survey. No channels exist for this survey. There are no designated anchorages, precautionary areas, safety fairways, traffic separation schemes, pilot boarding areas, or channels and range lines within the survey limits. 3 bottom samples were obtained in accordance with sections 7.2 and 7.2.2 of the HSSD 2016 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. H12946_F001: soft, grey, clay H12946_F002: soft, grey, mud with soft, grey, clay H12946_F003: soft, grey, clay 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 H12946_FXXX). No shoreline exists for this survey. No prior survey comparisons exist for this survey. No Aids to Navigation (ATONs) exist for this survey. No overhead features exist for this survey. No submarine features exist for this survey. No ferry routes or terminals exist for this survey. No platforms exist for this survey. No significant features 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 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 BASE 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. 2016-12-05