Basic Hydrographic Survey 2022 H13629 Alabama Louisiana Mississippi Northern Gulf of Mexico 24 NM South of Mobile Point 40000 2022-06-03 2022-06-16 2022-03-30 OPR-J350-FH-22 NOAA Ship Ferdinand Hassler (S250) CDR Michael O. Gonsalves MBES Kongsberg Maritime EM 2040 MBES Backscatter Kongsberg Maritime EM 2040 Atlantic Hydrographic Branch meters 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 16N, MLLW. All references to other horizontal or vertical datums in this report are applicable to the processed hydrographic data provided by the field unit. North American Datum 1983 Mean Lower Low Water VDatum Projected UTM 16 2022-06-30 CC0-1.0 (NOAA Field Units) CC0-1.0 https://creativecommons.org/publicdomain/zero/1.0/ https://creativecommons.org/publicdomain/zero/1.0/legalcode These data were produced by NOAA and are in the public domain within the United States. NOAA waives any potential copyright and related rights in these data worldwide through the Creative Commons Zero 1.0 Universal Public Domain Dedication (CC0). The survey area is located 24 NM South of Mobile Point, Alabama. This hydrographic survey was acquired in accordance with the requirements defined in the Project Instruction OPR-J350-FH-22. A total of 366.84 linear nautical miles of multibeam echosounder data with concurrent backscatter data comprise the mainscheme coverage of H13629. See Figure 1 for an overview of the sheet limits. Three crosslines, totaling 13.28 linear nautical miles, were acquired within the survey boundary of H13629 to ensure quality control. 29.903698 87.87234799999999 29.74259 87.69346 H13629 sheet limits (in blue) overlaid onto Chart 11006 file:///B:/OPR-J350-FH-22/Surveys/H13629/01_HDR/Reports/Descriptive_Report/Support%20Files/H13629_Sheet_limits.PNG The 2010 Deepwater Horizon oil spill released over 3 million barrels of oil in the Gulf of Mexico, by far the largest offshore oil spill in US history. In 2016, the Deepwater Horizon Trustees reached a settlement for natural resource injuries caused by the Deepwater Horizon oil spill. The Deepwater Horizon Trustees documented a footprint of over 770 square miles of injury to mesophotic and deep benthic habitat surrounding the wellhead and extending up the continental slope.  Accurate high-resolution bathymetric and habitat maps and data on the abundance and distribution of mesophotic and deep benthic habitats are needed to guide restoration. Only a small portion of the mesophotic and deepwater habitats in the Gulf of Mexico have been surveyed, and with the collaboration and partnership of NOAA’s Deepwater Horizon Program and the National Centers for Coastal and Ocean Science (NCCOS), the NOAA Ship Ferdinand R. Hassler will collect bathymetry and backscatter data in the region. This work supports one of many projects selected by the Open Ocean Trustee Implementation Group to restore natural resources injured by the Deepwater Horizon oil spill. The data collected will be foundational for exploring mesophotic and deepwater habitats of the marine ecosystem by informing ground truthing locations for underwater camera footage, sediment cores, grab samples, ROV, and AUV work and for identifying future restoration sites. The data will also update nautical charting products.  The entire survey is adequate to supersede previous data. Data acquired in H13629 meet multibeam echo sounder (MBES) coverage requirements for complete coverage, as required by the HSSD. This includes crosslines, NOAA allowable uncertainty, and density requirements. The entire survey is adequate to supersede previous data and is recommended for charting. Refer to the OPR-J350-FH-22 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, and any deviations from the DAPR are discussed in the following sections. In addition to the usual a priori estimates of uncertainty via device models for vessel motion and VDATUM, real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H13629. Real-time uncertainties were provided via EM 2040 MBES data and Applanix Delayed Heave RMS. Following post-processing of the real-time vessel motion, recomputed uncertainties of vessel roll, pitch, gyro and navigation were applied in CARIS HIPS and SIPS via a Smoothed Best Estimate of Trajectory (SBET) RMS file generated in Applanix POSPac. US3GC05M 456394 60 2022-06-09 2022-06-09 H13629_MB_VR_MLLW.csar CARIS VR Surface (CUBE) Variable Resolution 28.6 41.3 NOAA_VR Complete MBES H13629_MB_VR_MLLW_Final.csar CARIS VR Surface (CUBE) Variable Resolution 28.6 41.3 NOAA_VR Complete MBES Crosslines were collected, processed and compared in accordance with Section 5.2.4.2 of the HSSD for quality control. To evaluate crosslines, a surface generated via data strictly from mainscheme lines and a surface generated via data strictly from crosslines were created. From these two surfaces, a difference surface (mainscheme - crosslines = difference surface) was generated. Statistics show that the mean difference between depths derived from mainscheme data and crossline data was -0.01 meters (with mainscheme being shoaler) and 95% of nodes falling within +/- 0.26 meters (Figure 2). For the respective depths, the difference surface was compared to the allowable NOAA uncertainty standards. In total, 99.5% of the depth differences between H13629 mainscheme and crossline data were within allowable NOAA uncertainties. The surface was analyzed using the HydrOffice QC Tools Grid QA feature to determine compliance with specifications. Density requirements for H13629 were achieved with at least 99% of surface nodes containing five or more soundings as required by HSSD Section 5.2.2.3 (See Figure 3). Additionally, 99.5% of nodes within the surface meet NOAA Allowable Uncertainty specifications for H13629 (See Figure 4). There are no assigned junctions, features, bottom samples, maritime boundaries, dangers to navigation, aids to navigation, or shoreline present within the assigned H13629 sheet limits. H13629 crossline and mainscheme difference statistics file:///B:/OPR-J350-FH-22/Surveys/H13629/01_HDR/Reports/Descriptive_Report/Support%20Files/H13629_MB_4m_MLLW_MS-H13629_MB_4m_MLLW_XL_depth_delta.png H13629 Data density statistics file:///B:/OPR-J350-FH-22/Surveys/H13629/01_HDR/Reports/Descriptive_Report/Support%20Files/H13629_MB_VR_MLLW.QAv6.density.png H13629 allowable uncertainty statistics file:///B:/OPR-J350-FH-22/Surveys/H13629/01_HDR/Reports/Descriptive_Report/Support%20Files/H13629_MB_VR_MLLW.QAv6.tvu_qc.png No Horizontal and Vertical Control Report has been generated for H13629. ERS methods were used as the final means of reducing H13629 to MLLW for submission. Vessel kinematic data were post-processed using Applanix POSPac MMS processing software and RTX positioning methods described in the DAPR. A Smoothed Best Estimate of Trajectory (SBET) and associated error (RMS) data were applied to all MBES data in CARIS HIPS and SIPS. During real-time acquisition, all platforms received correctors from the Wide Area Augmentation System (WAAS) for increased accuracies similar to USCG DGPS stations. WAAS and SBETs were the sole methods of positioning for H13629 as no DGPS stations were available for real-time horizontal control. 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 Survey Summary 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, Standing and 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 Survey Summary Report. CDR Michael O. Gonsalves Chief of Party 2022-06-30 LT Daniel Helmricks Operations Officer 2022-06-30