OPR-K379-KR-19Corpus Christi, TX & ApproachesCorpus Christi, TX & ApproachesOcean SurveysH13224416 NM NE of Port AransasTexasUnited States50002019John R. BeanNavigable Area2019-03-062019-06-082019-08-29Multibeam Echo SounderSide Scan SonarMultibeam Echo Sounder BackscattermetersUTCAtlantic Hydrographic BranchThe information presented in this report and the accompanying digital data represents the results of surveys performed by Ocean Surveys, Inc. during the period of June 8, 2019 to August 29, 2019 and can only be considered as indicating the conditions existing at that time. Reuse of this information by client or others beyond the specific scope of work for which it was acquired shall be at the sole risk of the user and without liability to OSI.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 14N, MLLW. All references to other horizontal or vertical datums in this report are applicable to the processed hydrographic data provided by the field unit.ContractorThis survey provides hydrographic data for the Gulf of Mexico waters approaching the Texas coast northeast of Port Aransas. The general locations of the survey limits are presented in Table 1.28.12055397.04160127.83819596.673904Survey limits were acquired in accordance with the requirements in the Project Instructions and the HSSD.The following text is copied verbatim from the Project Instructions' Purpose and Location Section: "This project is located in Corpus Christi Bay, including the Corpus Christi Shipping Channel and offshore approaches. The U.S. Army Corps of Engineers maintains the channel which is dredged through the bay to the jetties of Port Aransas. The Corpus Christi Port primarily supports deepdraft vessels for export of petroleum and energy related products. In addition, the port supports seafood, industrial and agricultural industries in the state of Texas. Metals, stone products, glass, chemicals, and gypsum products are produced near Corpus Christi Bay. Six oil refineries and 1,500 wells are located near the bay as well as a large supply of natural gas. The Channel also serves as a conduit for commercial ship traffic between Houston terminuses and the Gulf. 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.All waters in survey area to an inshore limit of the NALL as defined in the HSSD and the Project Instructions.Complete Coverage (Refer to HSSD Section 5.2.2.3)Per the Project Instructions, towfish height requirements from HSSD Section 6.1.2.3 were modified for this task order to allow a towfish altitude of 6-20% of range scale.Survey H13224 MBES coverage overlaid on a composite of RNCs.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224_Survey-Coverage.jpgR/V Ocean Explorer014.120001155.18047.660R/V H.F. Stout017.5800021.6000.710031.700001176.78048.3704.001100066.142019-06-082019-06-272019-06-282109-06-292019-06-302019-07-012019-07-102101-07-112019-07-122019-07-132019-07-212019-07-222019-07-232019-07-242019-07-262019-08-032019-08-042019-08-202019-08-212019-08-232019-08-242019-08-252019-08-29The LNM for MBES-only development and fill-in lines were included under the heading "MBES Mainscheme" in Table 3. There was no SSS-only mileage for this survey.Refer to the project DAPR for a complete description of data acquisition and processing systems, survey vessels, quality control procedures, and data processing methods.R/V Ocean Explorer182R/V H.F. Stout90.76Teledyne RESONSeaBat 7125 SV2MBESEdgeTech4200SSSEdgeTech4125SSSApplanixPOS MV 320 v5Positioning and Attitude SystemAML OceanographicBaseXSound Speed SystemAML OceanographicMicroX SVSound Speed SystemAML OceanographicMVP30Sound Speed SystemTrimbleNetR9Positioning SystemAll equipment was installed, calibrated, and operated in accordance with the DAPR. If the investigation and fill-in lines are not included in the mainscheme mileage, then the crosslines acquired for this survey totaled 4.86% of mainscheme acquisition. All crosslines for Survey H13224 were acquired on June 8, 2019 (DN 159), the first day of surveying in this area. The crosslines were run approximately northwest-southeast, with mainscheme lines run perpendicular to the crosslines (Figure 2). Agreement between crossline and mainscheme data was very good, with no geographic pattern to the magnitude of discrepancy. A difference surface was generated in CARIS HIPS to compare a surface of only crosslines to a surface of only mainscheme data, and the average difference was found to be less than 0.01m. Figure 3 is a histogram showing the distribution of depth differences for all comparison grid cells considered. An overview of the crossline layout on a 1m surface created from mainscheme MBES data and colored by depth. A composite image of RNCs is visible in the background.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224_XL_overview.jpgThe graph shows a frequency distribution of the depth differences between the H13224 crossline vs mainscheme MBES data. Statistics from the depth difference sample set are displayed above the graph.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224-XL-main-histogram.jpgERS via VDATUM00.098R/V Ocean Explorer12R/V H.F. Stout12The methods used to minimize the uncertainty in the corrections to echo soundings are described in detail in the project DAPR. The Total Vertical Uncertainty Quality Check (TVU QC) "Ratio Method" was used to evaluate IHO uncertainty for the finalized surface of Survey H13224. The finalized surface was generated using the CARIS "Finalize Base Surface" utility, with the uncertainty source selected as the greater of the two values between the predicted uncertainty and the standard deviation (scaled to 95% CI). The FPM states that "[ratio] values which do not require further examination are from -1 to 0 and the values which do require further examination are from -100 to -1." Results from the TVU QC indicate that 99.99% of the nodes in the 1m resolution surface meet IHO Order 1 uncertainty specifications. Of more than 134 million nodes considered, 647 had a ratio value less than -1 and required further examination. Those nodes were all found to be on the edges of lines and associated with boat motion artifacts in the data. All but 1 node was found on a line collected by the smaller of the two vessels used for the survey, the R/V H.F. Stout, on August 21, 2019 (DN 233). More than 60% of these nodes were on the last line collected that day, after the field crew noted increasing swell height and chop in the water. Two current surveys and two prior surveys junction with Survey H13224. Figure 4 displays the location of the junction surveys for Project OPR-K379-KR-19, and the junctions specific to this survey are listed in Table 9. Junction analyses were conducted by generating a difference surface in CARIS HIPS for each pair of surveys to compare the MBES surfaces where they overlap. A histogram of the depth differences was plotted to show the relative agreement of the surveyed depths, and to indicate shoaling or deepening trends by positive or negative differences. The magnitude of differences were compared to the maximum allowable TVU for the water depths in Survey H13224. The HSSD defines junction discrepancies requiring further examination as those greater than the TVU * sqrt(2), which for the water depths in Survey H13224 was 0.71m to 0.78m.Survey junctions for Project OPR-K379-KR-19. file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224_Junction_Overview.jpgH11245400002004OceaneeringESurvey H11245, conducted in 2004 by Oceaneering, junctions with Survey H13224 along its southern and southeastern borders for a shared boundary of approximately 12km. Bathymetry data for Survey H11245 was not available through the NOAA National Centers for Environmental Information (NCEI) website, but it was provided to OSI by the AHB COR with the project files (see Appendix II for correspondence). The data consisted of a smooth sheet with a scale of 40000, which is sparse relative to the MBES data of Survey H13224 and so yielded a small sample of comparison cells. Overall, the two surveys showed good agreement with an average difference of 0.33m. Depth discrepancies for 97% of the cells were beneath the TVU-based difference threshold for their water depths and did not trigger further examination. Much of the southern tip of Survey H13224 was observed to be slightly deeper than charted, and this deepening trend is likely the source of those differences that are beyond the TVU-based difference threshold. Surface-to-surface difference histogram comparing Survey H11245 to H13224.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224-difference-H11245-histogram.jpgH11246400002005OceaneeringESurvey H11246, conducted in 2005 by Oceaneering, junctions with Survey H13224 on the eastern side of Survey H13224's southern tip. The shared border is approximately 5km long, and the overlap width is narrow towards the top of the junction but wider towards the bottom, ranging from approximately 100m to 1km. Mainscheme lines between the two surveys are at an angle to one another, not quite perpendicular, creating a patchwork of overlap regions with moderate data density. The junction area includes regions of Survey H13224 that have a notable difference from charted soundings, and so the range of discrepancy between the two surveys is high. The median discrepancy is only 0.11m, and 91.75% of the survey junction comparison cells were beneath the maximum allowable TVU-based discrepancy threshold for the deepest water measured in the Survey H13224. The depth discrepancies are in line with observed changes between H13224 surveyed depths and charted depths. Surface-to-surface difference histogram comparing Survey H11246 to H13224.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224-difference-H11246-histogram.jpgH1322250002019Ocean Surveys, Inc.SThe southern edge of Survey H13224 shares a boundary with current Survey H13222. Survey H13222 has complete MBES coverage in the junction area, so it is relatively dense with data. The junction area is approximately 1km long and 230-300m wide. Depth differences between the two surveys were minimal, with an average difference of less than 0.02m and a maximum difference of 0.20m. This is well under the maximum allowable TVU-based discrepancy for this survey.Surface-to-surface difference histogram comparing Survey H13222 to H13224.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224-difference-H13222-histogram.jpgH13223200002019Ocean Surveys, Inc.EThe junction between H13223 and H13224 is described in the DR for Survey H13223.Sonar system quality control checks were conducted as detailed in the DAPR.None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.SSS RefractionDynamic sound speed changes affected the SSS imagery at times, causing refraction in the outer ranges of the SSS swath (Figure 8). To ensure coverage with high quality SSS data, lines with excessive refraction were rejected. If clear SSS imagery from adjacent lines was insufficient to cover the area of refraction, portions of the line were re-run.SSS imagery showing refraction in both port and starboard channels.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224-FAS-Refraction.jpgFish in SSS Imagery and MBES DataAn abundance of fish and marine sea life were seen in the SSS and MBES data, either as lone swimmers or in schools (Figures 9 and 10). In cases where large shadows in the SSS imagery or gaps in the MBES data were created by schools of fish or dolphins, additional coverage was obtained to ensure no significant features were located in these fish and dolphin shadows. SSS and MBES images showing a school of fish in the port channel and the acoustic shadow it casts in each dataset. Rejected soundings are colored yellow.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224-FAS-Fish.jpgAn example of dolphins appearing in the water column of the MBES and the SSS, and the acoustic shadows cast in each dataset. Rejected soundings are colored yellow.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224-FAS-Dolphins.jpgMBES "Blowouts"The Reson 7125 systems experienced occasional bursts of motion-induced noise or “blowouts,” typically affecting between one and four sequential profiles. The noise bursts were infrequent and were encountered when sea state worsened. Accepted data affected by blowouts did not show any coverage holidays in the final MBES surface. This figure shows how cavitation noise at the MBES transducer head is presented in the converted data. Rejected soundings are colored yellow.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224-FAS-MB-Blowout.jpgOn board the R/V Ocean Explorer, sound speed profile data were acquired with the AML MVP30 approximately every 15 minutes as documented in the DAPR. On board the R/V H.F. Stout, sound speed profiles were acquired with the AML Base X at intervals of approximately 1-2 hours.All MBES lines were sound speed corrected using CARIS HIPS' "Nearest in Distance Within Time" method. The time interval used was 2 hours for the R/V H.F. Stout and 1 hour for the R/V Ocean Explorer. OSI submitted H13224 sound speed data in NetCDF format to the National Centers for Environmental Information (NCEI) on Jan 6, 2020 via the S2N tool. NCEI assigned Accession Number 0208349 to the R/V Ocean Explorer data and Accession Number 0208350 to the R/V H.F. Stout data. Correspondence regarding the NCEI data submission is included in Appendix II.Survey H13224 was conducted to achieve Complete Coverage, using 100% SSS coverage with concurrent MBES (Option B; HSSD Section 5.2.2.3). All potentially significant features located by mainscheme SSS or MBES were also developed with MBES data to meet the Complete Coverage Multibeam requirements. For single-resolution surfaces, HSSD Section 5.2.2.3 specifies a grid resolution of 1m for depths less than 20m, which covers all water depths of Survey H13224. The CARIS HIPS and SIPS "Compute Statistics" tool was used to verify that the grid nodes met the density coverage requirements, defined in the HSSD as having at least 95% of the nodes populated with at least 5 soundings. The finalized surface for Survey H13224 meets this requirement, with 99.54% of nodes in the 1m resolution surface having 5 or more soundings. The survey methods used to meet coverage requirements did not deviate from those described in the DAPR. All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.All equipment and survey methods were used as detailed in the DAPR.NOAA Profile Version 2019H13224_MB_1m_MLLW_Final.csarCARIS Raster Surface (CUBE)13.07617.380NOAA_1mComplete MBESH13224_MB_1m_MLLW_.csarCARIS Raster Surface (CUBE)13.07617.380NOAA_1mComplete MBESH13224_SSSAB_1m_600and900kHz_1of2.tifSSS Mosaic1N/A100% SSSH13224_SSSAB_1m_600and900kHz_2of2.tifSSS Mosaic1N/A200% SSSIn addition to the surfaces in Table 10, a set of 0.25m SSS mosaic images were submitted in Enhanced Compressed Wavelet (ECW) format to assist with the survey review.Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR.Mean Lower Low WaterERS via VDATUMbuff_xyNAD83-MLLW_geoid12b.csarNorth American Datum 1983Projected UTM 14Smart BaseCorpus Christi R2TXCCPort LavacaTXPVBeevilleTXBEKingsvilleTX2006KVTXLaguna VistaTXLNClute CoopDWI1AliceTXAIVictoriaTXVARaymondvilleTXRVOSI Port AransasOSPAThe primary CORS stations used for Project OPR-379-KR-19 are listed in Table 12. Additional stations used on 8 or fewer survey days include TXFE, DEV1, TXBC, TXED, LCSM, TXKC, ANG5, COH2, TXAG, and TXBV. See the HVCR for details.Chart comparisons were conducted visually using a difference surface generated by subtracting ENC soundings from a finalized CUBE depth surface of survey MBES data. The difference surface, shown in Figure 12, represents regions of deepening with negative depth differences (cool colors), shoaling with positive depth differences (warm colors), and grey indicating areas of no significant change. The CUBE depth surface of survey data used for this difference surface had a resolution of 10m. ENC soundings were taken from the latest editions of the charts available on the NOAA OCS website. Soundings from the four assigned ENCs that cover H13224 were combined into a single sounding set using data from only the largest-scale chart that provided coverage at any given point. The ENCs used for final comparisons were submitted with the survey deliverables. Local NTMs and NTMs from March 6, 2019 to August 30, 2019 were reviewed in conjunction with the chart comparison, but no notices were made during this time that concerned Survey H13224. The last NTM reviewed was No. 35, dated August 31, 2019, and the last Local NTM reviewed was notice 35/19, dated August 28, 2019. A depth difference surface overlaid on a composite of RNCs provides an overview of the areas of change between charted depths and H13224 surveyed soundings.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224_Difference_Map.jpgA depth surface with contours shows the surveyed 30-foot contour to be slightly shoreward from the charted contour.file:///H:/Survey/H13224_K379_KR_19/AHB_H13224/01_SAR/Reports/Survey/Descriptive_Report/Report/H13224/H13224_Chart-Comparison.jpgUS4TX21M80000202018-11-062019-08-19falseENC US4TX21M covers the southern tip and south edge of Survey H13224, though it is not the largest-scale ENC available for much of its coverage. Surveyed depths from this chart are generally slightly deeper than charted, with a few small spots of shoaling. The charted 30-foot contour runs lengthwise through the southern tip of the survey area, and surveyed soundings show the contour to be similar or slightly shoreward from charted (Figure 13).US4TX28M80000192019-06-102019-07-10falseENC US4TX28M covers all but the southern tip and southern edge of Survey H13224. Surveyed depths in this area were nearly all slightly deeper than charted, on the order of -0.5 to -1m, with a few small patches of shoaling and some areas showing no change.US5TX22M40000382019-08-122019-08-12falseENC US5TX22M covers only a small slice of the southern tip of Survey H13224. Soundings in this area were surveyed to be slightly deeper or unchanged from charted. The charted 30-foot contour runs lengthwise through the southern tip of the survey area, and surveyed soundings show it to be similar or slightly shoreward from charted (Figure 13).US5TX27M20000312019-07-092019-08-12falseENC US5TX27M covers the very southern portion of Survey H13224. Depths in this area vary from charted in patches by approximately -1.5m to +1m, with consistent deepening evident along the edge near the channel and a notable spot of shoaling just north of there. The charted 30-foot contour runs lengthwise through the southern tip of the survey area, and surveyed soundings show the contour to be similar or slightly shoreward from charted (Figure 13).No Maritime Boundary Points were assigned for this survey.There were 4 charted wrecks and 2 charted obstructions assigned in the CSF for Survey H13224. Only 1 charted feature was found to be present, a tall wreck in the northern part of the survey area. The wreck was surveyed approximately 140m distant from its charted position, and over 200m distant from the ATON intended to mark it. Due to this, the wreck's new position was submitted as a DTON. There were 12 new features in Survey H13224, 9 obstructions and 3 wrecks. Of these new features, 1 wreck and 3 obstructions were submitted as DTONS. For details and images of the new uncharted features, see the FFF. No charted shoals were present within Survey H13224, and no potentially hazardous features other than those submitted as DTONS. There were 5 DTONS submitted for Survey H13224; see the FFF for details. 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 11 bottom samples collected in Survey H13224. The sediment in this area was entirely found to be mud, with 6 samples containing shells or broken shells as well. See the FFF for further details and images of each sample.Shoreline was not assigned in the Hydrographic Survey Project Instructions or Statement of Work.There were 2 ATONs charted within Survey H13224, both of which were surveyed near their charted positions. One was a Texas A&M Oceanographic Buoy, which was reported as having washed up on shore some time after the survey vessel covered its position. The buoy has since been replaced, therefore the surveyed position in the FFF may not precisely reflect the new location. The other ATON, "Shoreline Ten Wreck Lighted Buoy WR2", marks a notable shipwreck obstruction. OSI surveyed the ATON to be 60 meters off station, and reported this discrepancy to the USCG via their online reporting tool. However, the buoy was over 200m distant from the wreck it is marking, as the wreck is not at its charted position either. OSI reported the new position of the wreck as a DTON and recommends the buoy be relocated to better mark the wreck. See the FFF for details on the wreck and buoy positions.No overhead features exist for this survey.There were 3 submarine pipelines assigned for Survey H13224. None of them were observed to be elevated or exposed. In addition to the ENC and the CSF, pipeline data from the Bureau of Ocean Energy Management (BOEM) were reviewed prior to field operations and during data processing to identify any potential uncharted pipelines in the survey area. There were 2 BOEM pipelines within Survey H13224, only 1 of which corresponded to a pipeline in the CSF and ENC. The uncharted BOEM pipeline was also not observed to be elevated or exposed. The BOEM pipeline data (last updated on Oct 1, 2019) were obtained as a shape file "ppl_arcs.shp" from the BOEM website (https://www.data.boem.gov/Main/Mapping.aspx) and re-projected as a .DXF file “BOEM_Pipelines_UTM_14N_NAD83_Meters.dxf.” These files are included with the digital deliverables for Survey H13224.There were 20 charted platforms assigned in the CSF for Survey H13224. Of these, 16 were disproved and 4 were found to be present. No uncharted platforms were observed. At the position of 1 of the charted platforms, 2 distinct superstructures were observed. These are represented by 2 new features in the FFF. The remaining 3 existing platforms are also included in the FFF as new features, as they are sufficiently distant from their charted positions to merit a new entry. See the FFF for details. In addition to the ENC and the CSF, BOEM platform data were reviewed prior to field operations and during data processing to identify any potential uncharted BOEM platforms in the survey area. There were no BOEM platforms within Survey H13224. The BOEM platform data (last updated on Oct 1, 2019) were obtained as a shape file "platform.shp" from the BOEM website (https://www.data.boem.gov/Main/Mapping.aspx) and re-projected as a .DXF file “BOEM_Platforms_UTM_14N_NAD83_Meters.dxf.” These files are included with the digital deliverables for Survey H13224.No ferry routes or terminals exist for this survey.No abnormal seafloor and/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 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 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 (2018), Field Procedures Manual (2014), Project 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.John R. BeanChief of Party2020-01-23David T. SomersData Processing Manager2020-01-23