OPR-J315-KR-21MississippiApproaches to Pascagoula, Louisiana, Mississippi, and AlabamaDavid Evans and AssociatesH134882Horn Island Pass and ApproachMississippiUnited States100002021Jonathan L. Dasler, PE, PLS, CHNavigable Area2021-04-272021-07-202021-10-13Multibeam Echo Sounder Multibeam Echo Sounder BackscattermetersUTCAtlantic Hydrographic BranchAny 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.ContractorDavid Evans and Associates, Inc. (DEA) conducted a hydrographic survey of the assigned area in the vicinity of Mississippi. Survey H13488 was conducted in accordance with the Statement of Work and Hydrographic Survey Project Instructions dated April 27, 2021. The Hydrographic Survey Project Instructions reference the National Ocean Service (NOS) Hydrographic Surveys Specifications and Deliverables Manual (HSSD) (April 2021) as the technical requirements for this project.30.203710305688.607146694430.0762188.2907626944Survey limits were surveyed in accordance with the requirements in the Project Instructions and the HSSD. The assigned survey areas are outlined in Figure 1. OPR-J315-KR-21 Assigned Survey Areasfile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/OPR-J315-KR-21_Assigned_Survey_Areas.pngThe purpose of this survey, defined in the Project Instructions, is as follows: “The Port of Pascagoula, Mississippi is ranked as the 25th busiest by total tons of commerce in the US (1). This proposed survey area covers approximately 189 square nautical miles of the approaches to Pascagoula and Gulfport as well as sections of the Intercoastal Waterway (ICW) between Louisiana and Alabama. The region has been affected by several recent hurricanes so it is expected that modern hydrographic techniques will find significant changes to the seabed since the most recent surveys. Survey data from this project are intended to supersede all prior survey data in the common area." (1) The U.S. Coastal and Inland Navigation System 2019 Transportation Facts & Information, Navigation and Civil Works Decision Support Center, USACEThe entire survey is adequate to supersede previous data.All waters in survey areaAcquire backscatter data during all multibeam data acquisition (Refer to HSSD Section 6.2).All waters in survey areaComplete Coverage (Refer to HSSD Section 5.2.2.3).Complete Coverage was obtained over the survey area in depths greater than 3.5 meters relative to chart datum using 100% multibeam echosounder (MBES) and backscatter. This coverage type follows Option A of the Complete Coverage requirement specified in Section 5.2.2.3 of the 2021 HSSD. Figure 2 depicts the H13488 survey outline.H13488 Survey Outlinefile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H88_SurveyOutline.pngS/V Blake01879.010000090.38001879.010000090.3804.811600052.322021-07-202021-07-212021-07-222021-07-252021-07-262021-07-272021-07-282021-07-292021-08-032021-08-042021-08-052021-08-062021-08-072021-08-082021-08-092021-08-112021-08-122021-08-132021-08-152021-10-062021-10-13The OPR-J315-KR-21 Data Acquisition and Processing Report (DAPR), submitted with this survey, details equipment and vessel information as well as data acquisition and processing procedures. There were no vessel or equipment configurations used during data acquisition that deviated from those described in the DAPR. The S/V Blake is an 82-foot aluminum catamaran with a 27-foot beam and a draft of 4.5 feet (Figure 3).S/V Blake824.5S/V Blakefile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/Figure1_OPR-J315-KR-21_SV_Blake.jpgTeledyne RESONSeaBat T50-RMBESApplanixPOS MV 320 v5Positioning and Attitude SystemAML OceanographicMicroX SVSound Speed SystemAML OceanographicMVP30-350Sound Speed SystemMultibeam crosslines were run across 4.81% of the entire survey area to provide a varied spatial and temporal distribution for analysis of internal consistency within the survey data. Crossline analysis was performed using the CARIS Hydrographic Information Processing System (HIPS) Quality Control (QC) Report tool, which compares crossline data to a gridded surface and reports results by beam number. Crosslines were compared to a 1-meter CUBE surface encompassing mainscheme, fill, and investigation data for the entire survey area. DEA performed an additional crossline analysis using the NOAA Pydro Compare Grids tool to analyze the differences between gridded mainscheme depths and gridded crossline depths. Input grids were 1-meter resolution Combined Uncertainty and Bathymetry Estimator (CUBE) surfaces of mainscheme and crossline depths. Results from the crossline to mainscheme difference analysis are depicted in Figure 4, with units represented in meters. H13488 Crossline Differencefile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_1m_XL-H13488_1m_MS_only_depth_delta.pngERS via VDATUM0.050.152S/V Blaken/a1.0n/a0.5Additional discussion of these parameters is included in the DAPR. The S/V Blake used an AML MVP30-350 with integrated Micro SVP&T to acquire sound speed measurements. The measurement uncertainty for these sensors is listed in the Moving Vessel Profiler (MVP) column in Table 8. During surface finalization in HIPS, the "Greater of the two values" option was selected, where the calculated uncertainty from Total Propagated Uncertainty (TPU) is compared to the standard deviation of the soundings influencing the node, and where the greater value is assigned as the final uncertainty of the node. The uncertainty of the finalized surfaces increased for nodes that had a standard deviation greater than TPU. To determine if the surface grid nodes met International Hydrographic Organization (IHO) Order 1a specification, a ratio of the final node uncertainty to the allowable uncertainty at that depth was determined. As a percentage, this value represents the amount of error budget utilized by the Total Vertical Uncertainty (TVU) at each node. Values greater than 100% indicate nodes exceeding the allowable IHO uncertainty. The resulting calculated TVU values of all nodes in the submitted finalized surfaces are shown in Figures 5 and 6. Node TVU Statistics - 1 meter, Finalizedfile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_MB_1m_MLLW_Final.QAv6.tvu_qc.pngNode TVU Statistics - 2 meter, Finalizedfile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_MB_1m_MLLW_Final.QAv6.density.pngSurvey H13488 junctions with current surveys H13487 and H13490, and prior contemporary surveys H12356, H13065, and H13066. Figure 7 depicts H13488 and the junctioning surveys.Survey Junctions with Registry Number H13488file:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H88_Jxns.pngH13487100002021David Evans and Associates, Inc.NAt the time of writing, data from survey H13487 was still being processed. The Descriptive Report for H13487 will include the junction analysis with H13488. H13490200002021David Evans and Associates, Inc.WAt the time of writing, data from survey H13490 was still being processed. The Descriptive Report for H13490 will include the junction analysis with H13488. H12356200002011David Evans and Associates, Inc.NThe mean difference between H13488 and H12356 survey depths is 25 centimeters (H13488 deeper than H12356), shown in Figure 8. GPS Tides computed for prior survey H12356 used a VDatum-based Mean Lower Low Water (MLLW) separation model that has a mean separation difference of 10 centimeters over the area of junction overlap. Removing the model differences from the analysis would improve the junction comparison between surveys H12356 and H13488 to 15 centimeters. In addition, GPS Tides for survey H12356 were computed from a post-processed single base navigation solution where survey H13488 was post-processed using Real Time Extended (RTX) methods. Single base processing relied on Global Navigation Satellite System (GNSS) data from a temporary base station (HORN) installed on Horn Island in support of the prior survey. Distribution Summary Plot of Survey H13488 1-meter vs H12356 1-meterfile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_MB_1m_MLLW-H12356_1m_MLLW_1of2_Final_depth_delta.pngH13065200002017David Evans and Associates, Inc.NThe mean difference between H13488 and H13065 survey depths is 30 centimeters (H13488 deeper than H13065), shown in Figure 9. The area of junction overlap between the survey includes a large area of sand waves, which also encompasses several Outer Continental Shelf borrow sites. Restricting the junction analysis to the western side of the survey area, away from the sediment borrow sites, results in a mean difference of 14 centimeters. See Section D.2.9 for additional discussion on the Outer Continental Shelf Borrow Sites. Survey H13488 was reduced to MLLW using Tidal Constituent and Residual Interpolation (TCARI), incorporating water levels from National Water Level Observation Network (NWLON) stations at Dauphin Island, Alabama (8735180), Pascagoula NOAA Lab, Mississippi (8741533), and Bay Waveland (8747437). Distribution Summary Plot of Survey H13488 1-meter vs H13065 1-meterfile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_MB_1m_MLLW-H13065_MB_1m_MLLW_Final_depth_delta.pngH13066200002017David Evans and Associates, Inc.NThe mean difference between H13488 and H13066 survey depths is 9 centimeters (H13488 deeper than H13066), shown in Figure 10.Distribution Summary Plot of Survey H13488 1-meter vs H13066 1-meterfile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_MB_1m_MLLW-H13066_MB_1m_MLLW_Final_depth_delta.pngQuality control is discussed in detail in Section B of the DAPR. Multibeam data were reviewed at multiple levels of data processing, including CARIS HIPS conversion, subset editing, and analysis of anomalies revealed in CUBE surfaces.Real-Time HeaveThe following lines were processed with real-time heave due to logging errors during acquisition that resulted in no delayed heave file being recorded: 2021BL2200010 2021BL2200019 2021BL2200027 2021BL2200033 None ExistThere were no other factors that affected corrections to soundings.Approximately 20-minute intervals For H13488 survey operations, casts were distributed both temporally and spatially based on observed changes in sound speed profiles. Sound speed readings were applied in CARIS HIPS using the nearest in distance within a two-hour interval. All cast profiles were acquired within 500 meters of the survey limits. During H13488 survey operations, the S/V Blake occasionally acquired the first cast of the day after starting multibeam data acquisition. In all cases, the first cast of the day was acquired within five minutes of the first sonar ping of the day. This issue occurred on the following days: July 22, 2021 (DN203) July 26, 2021 (DN207) July 27, 2021 (DN208) July 28, 2021 (DN209) July 29, 2021 (DN210) August 7, 2021 (DN219) Survey speeds were maintained to meet or exceed along-track sounding density requirements. Multibeam data were thoroughly reviewed for holidays and areas of poor-quality coverage due to biomass, vessel wakes, or other factors.Density The sounding density requirement of 95% of all nodes, populated with at least five soundings per node, was verified by analyzing the density layer of the finalized surface. Individual surface results are stated in Figures 11 and 12. Node Density Statistics - 1 meters, Finalized file:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_MB_1m_MLLW_Final.QAv6.tvu_qc.pngNode Density Statistics - 2 meters, Finalized file:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_MB_1m_MLLW_Final.QAv6.density.pngData reduction procedures for survey H13488 are detailed in the DAPR. All sounding systems were calibrated as detailed in the DAPR.Multibeam backscatter was logged in HYPACK 7K format and included with the H13488 digital deliverables. Data were processed periodically in CARIS HIPS to evaluate backscatter quality, but the processed data is not included with the deliverables. For data management purposes, the names of multibeam crosslines have been appended with the suffix _XL. This change was made to HIPS files only. The original file names of raw data files (HYPACK HSX and 7K) have been retained. CARISHIPS/SIPS11.3.8NOAA Profile Version 2021A detailed listing of all data processing software is included in the OPR-J315-KR-21 DAPR.H13488_MB_1m_MLLW.csarCARIS Raster Surface (CUBE)16.98521.924NOAA_1mComplete MBESH13488_MB_1m_MLLW_Final.csarFinalized CARIS Raster Surface (CUBE)16.98520.000NOAA_1mComplete MBESH13488_MB_2m_MLLW.csarCARIS Raster Surface (CUBE)26.98921.903NOAA_2mComplete MBESH13488_MB_2m_MLLW_Final.csarFinalized CARIS Raster Surface (CUBE)218.00021.903NOAA_2mComplete MBESBathymetric grids were created relative to MLLW in CUBE format using Complete Coverage resolution requirements as specified in the HSSD. A summary of the horizontal and vertical control for survey H13488 follows.Mean Lower Low WaterERS via VDATUMOPR-J315-KR-21_100m_NAD83_2011-MLLW.csarNorth American Datum 1983Projected UTM 16RTXThe separation model listed in Table 12 was provided with the Project Instructions and used for sounding correction within the assigned survey area. Real-time navigation for all MBES survey lines were overwritten with post-processed navigation solutions in Smooth Best Estimate of Trajectory (SBET) format. Post-processed solutions were generated using Applanix POSPac MMS using the Trimble CenterPoint RTX option, which relies on precise satellite orbit and timing information to create centimeter-level positioning and elevation without the use of traditional local base stations. Information on survey control is detailed in the DAPR.The chart comparison was performed by comparing H13488 survey depths to a digital surface generated from the band 4 and band 5 electronic navigational charts (ENCs) covering the survey area. A 5-meter product surface was generated from a triangular irregular network (TIN) created from the ENC’s soundings, depth contours, and depth features. An additional 5-meter HIPS product surface of the entire survey area was generated from the 1-meter CUBE surface. The chart comparison was conducted by creating and reviewing a difference surface using the ENC surface and survey surface as inputs. The chart comparison also included a review of all assigned charted features within the survey area. The results of the comparison are detailed below. The relevant charts used during the comparison were reviewed to check that all United States Coast Guard (USCG) Local Notice to Mariners (LNMs) issued during survey acquisition, and impacting the survey area, were applied and addressed by this survey. The ENCs used in the chart comparison are listed in Table 13. Figures 13 through 16 show the magnitude of differences along the comparison area. Sand borrow site areas are the regular-shaped deeper areas apparent in Figures 14 and 15.Depth Difference Between H13488 and US4MS12M Area 1 of 3.file:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_Chart_comp_US4_1.pngDepth Difference Between H13488 and US4MS12M Area 2 of 3.file:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_Chart_comp_US4_2.pngDepth Difference Between H13488 and US4MS12M Area 3 of 3.file:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_Chart_comp_US4_3.pngDepth Difference Between H13488 and US5MS22M.file:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_Chart_comp_US5.pngUS5MS22M20000502021-09-212021-09-21US4MS12M80000452020-10-142020-10-14No shoals or potentially hazardous features exist for this survey.Numerous charted features exist within the limits of Sheet H13488. All assigned features included in the project Composite Source File (CSF) have been addressed by the survey and are included in the Final Feature File (FFF). All disproved features have been included in the FFF with a description of "Delete." All new features have been included in the FFF with the surveyed feature depicted and a description of "New."No uncharted features exist for this survey.The southern end of the Pascagoula Bar Channel is charted within the survey area. No survey depths within the channel were found to be shoaler than charted. There are no charted precautionary areas, traffic separation schemes, pilot boarding areas, or channel and range lines within the survey limits. The survey area encompasses the Horn Island Pass to Mobile Ship Channel Safety Fairway, the Horn Island Pass to Mobile Ship Channel Safety Fairway, and the Pascagoula Safety Fairway (33 CFR 166.200). An Explosive Anchorage Area (33 CFR 110.194b) is also charted within the survey area. No new obstructions or dangers were located within the fairways or the charted anchorage. The hydrographer recommends encoding the name of safety fairways in the ENCs. Safety fairway names are included in the Code of Federal Regulations (CFR). The northern end of the survey area extends into the charted Restricted Area surrounding the Gulf Islands National Seashore (GUIS). All Aids to Navigation (AtoNs) charted within the survey were found to be on station and serving their intended purpose. No Maritime Boundary Points were assigned for this survey.Sixteen bottom samples were acquired on October 13, 2021 (DN286). The bottom sampling plan followed suggested sample locations included in the provided Project Reference File (PRF). Minor adjustments were made to the recommended sampling locations with approval from the Contracting Officer's Representative (COR). Correspondence is included in Appendix II - Supplemental Survey Records & Correspondence of this report. No overhead features exist for this survey.There are 19 submerged pipelines and one submarine cable charted in the survey area. One section of potentially exposed pipeline was reported following HSSD 1.7.1 and 1.7.3. Correspondence related to this reporting is included in Appendix II. The item has also been included in the FFF as an obstruction. There are three offshore platforms within the survey area. Holidays are present in the bathymetric surface under and surrounding the platforms where it was not possible to obtain valid multibeam coverage. See the H13488 FFF for more details.No ferry routes or terminals exist for this survey.No abnormal seafloor and/or environmental conditions exist for this survey.Multiple Outer Continental Shelf Borrow Sites are located within the H13488 survey area. Material has been sourced from these sites to fill “Camille Cut” on Ship Island as part of the United States Army Corps of Engineers (USACE) Mississippi Coastal Improvements Program (MsCIP) Comprehensive Barrier Island Restoration. Evidence of dredging is visible in the bathymetric surface shown in Figure 17.Outer Continental Shelf Borrow Site Polygons in the Vicinity of the H13488 Survey Areafile:///B:/OPR-J315-KR-21/Surveys/H13488/01_HDR/Reports/Descriptive_Report/H13488_DR/SupportFiles/H13488_Borrow_Sites.jpgNo new surveys or further investigations are recommended for this area.According to the National Charting Plan, the ENCs covering the survey area are slated to be reschemed to include new Band 2 through Band 5 cells based on a gridded production scheme. The hydrographer has no ENC scale recommendations for the 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 and Specifications 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.Jonathan L. Dasler, PE, PLS, CHNSPS-THSOA Certified Hydrographer, Chief of Party2022-01-05Jason Creech, CHNSPS-THSOA Certified Hydrographer, Charting Manager / Project Manager2022-01-05James GuilfordIHO Cat-A Hydrographer, Lead Hydrographer2022-01-05Michael RedmayneIHO Cat-A Hydrographer, Lead Hydrographer2022-01-05Data Acquisition and Processing Report2021-12-09