OPR-K379-KR-19Corpus Christi, TX & ApproachesCorpus Christi, TX & ApproachesOcean SurveysH13223318 NM NE of Port AransasTexasUnited States200002019John R. BeanNavigable Area2019-03-062019-06-082019-08-23Multibeam 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 23, 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 1.28.07531296.88713627.89264296.625211Survey 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.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 H13223 MBES coverage overlaid on a composite of RNCs.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223_Survey-Coverage.jpgR/V Ocean Explorer0285.19000706.62039.2800285.19000706.62039.2803.961000056.012019-06-082019-06-092019-06-102019-06-112019-06-122019-06-132019-06-142019-06-182019-06-192019-06-282019-06-292019-08-032019-08-042019-08-222019-08-23The 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. Stout90.76The R/V Ocean Explorer collected all of the sonar data in Survey H13223. A smaller vessel, the R/V H.F. Stout, collected the bottom samples for this survey. Teledyne RESONSeaBat 7125 SV2MBESEdgeTech4200SSSApplanixPOS 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 4.18% of mainscheme acquisition. All crosslines for Survey H13223 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 median difference was 0.03m. 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, with a composite image of RNCs in the background.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223_XL_overview.jpgA frequency distribution of the depth differences between H13223 crossline vs mainscheme MBES data. Statistics from the depth difference sample set are displayed above the graph.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223-XL-main-histogram.jpgERS via VDATUM00.098R/V Ocean Explorer12The 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 surfaces of Survey H13223. The finalized surfaces were 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 100% of the nodes in both the 1m resolution surface and the 2m resolution surface meet IHO Order 1 uncertainty specifications.One current survey and one prior survey junction with Survey H13223. 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 H13223. The HSSD defines junction discrepancies requiring further examination as those greater than the TVU * sqrt(2), which for the water depths in Survey H13223 was 0.76m to 0.82m. Survey junctions for Project OPR-K379-KR-19. file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223_Junction_Overview.jpgH11245400002004OceaneeringESurvey H11245, conducted in 2004 by Oceaneering, junctions with Survey H13223 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 H13223 and so yielded a small sample of comparison cells. Overall, the two surveys showed good agreement with an average difference of 0.26m and no notable spatial pattern in the differences. Depth discrepancies for 100% of the cells were beneath the TVU-based difference threshold for their water depths and did not trigger further examination.Surface-to-surface difference histogram comparing Survey H11245 to H13223.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223-difference-H11245-histogram.jpgH1322450002019Ocean Surveys, Inc.WCurrent Survey H13224 junctions with Survey H13223 along a shared border of over 28km on the western boundary of H13223. The mainscheme lines of both surveys run parallel to their shared border and they are closely aligned with one another, giving a junction area that includes nearly the full length of two mainscheme lines. The crosslines are also in alignment. Depth differences between the two surveys were minimal, with an average difference of less than 0.01m. All of the comparison cells were beneath the TVU-based difference threshold and did not require further examination. Surface-to-surface difference histogram comparing Survey H13224 to H13223.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223-difference-H13224-histogram.jpgSonar 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 7). 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 the port channel.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223-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 8 and 9). 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/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223-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. The images are of the same dolphin sighting event, however, because the sidescan was towed, the dolphin positions in the MBES do not precisely match the SSS. Rejected soundings are colored yellow.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223-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 surfaces. 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/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223-FAS-MB-Blowout.jpgOn board the R/V Ocean Explorer, sound speed profile data were acquired with the AML MVP30 approximately every 15 minutes.All MBES lines were sound speed corrected using CARIS HIPS' "Nearest in Distance Within Time" method. The time interval used was 1 hour. OSI submitted H13223 sound speed data in NetCDF format to the National Centers for Environmental Information (NCEI) on January 6, 2020, via the S2N tool. NCEI assigned Accession Number 0208349 to the R/V Ocean Explorer data. Correspondence regarding the NCEI data submission is included in Appendix II.Survey H13223 was conducted to achieve Complete Coverage, using 100% SSS coverage with concurrent MBES for the majority of the area (Option B; HSSD Section 5.2.2.3), and Complete Coverage Multibeam for the southeastern corner of the survey (Option A; 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 and a grid resolution of 2m for depths between 18m and 40m. Water depths in Survey H13223 were surveyed to be between 15m and 23m, therefore two separate single-resolution grids were submitted to meet the resolution requirements: a 1m grid for depth shoaler than 20m and a 2m grid for depths greater than 18m. The survey area covering depths between 18m and 20m is represented in both grids. 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. Both surfaces meet this requirement, with 99.60% of nodes in the 1m resolution surface and 99.75% of nodes in the 2m 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 2019H13223_MB_1m_MLLW_Final.csarCARIS Raster Surface (CUBE)115.59120NOAA_1mComplete MBESH13223_MB_1m_MLLW.csarCARIS Raster Surface (CUBE)1NOAA_1mComplete MBESH13223_MB_2m_MLLW_Final.csarCARIS Raster Surface (CUBE)21822.69NOAA_2mComplete MBESH13223_MB_2m_MLLW.csarCARIS Raster Surface (CUBE)2NOAA_2mComplete MBESH13223_SSSAB_1m_600kHz_1of2.tifSSS Mosaic1N/A100% SSSH13223_SSSAB_1m_600kHz_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 11 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. There are two ENCs assigned in the Project Instructions that, together, provide coverage for all of Survey H13223 at the largest scale available (1:80000). Their soundings were combined without overlap into a single sounding set for comparison. 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. 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. Entries affecting the chart within the survey area are addressed with their corresponding ENC.A depth difference surface overlaid on a composite of RNCs provides an overview of the areas of change between charted depths and H13223 surveyed soundings.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223_Difference_Map.jpgA depth surface with contours shows the surveyed 60-foot contour to be shoreward from the charted contour.file:///H:/Survey/H13223_K379_KR_19/AHB_H13223/01_SAR/Reports/Survey/Descriptive_Report/Report/H13223/H13223/H13223_Chart-Comparison.jpgUS4TX28M80000192019-06-102019-07-10falseFor the majority of Survey H13223, ENC US4TX28M is the largest-scale chart available. In general, surveyed data was slightly deeper than charted soundings, but the survey contains several large areas of no significant change as well. None of the areas of deepening showed a change greater than 5 feet, and much was less than 2 feet deeper than charted. One small patch indicated a spot of shoaling in the northern third of the survey area, but the change was less than 1 foot. The charted 60-foot contour runs lengthwise through the survey area, and survey data shows the contour to have moved slightly shoreward from charted (Figure 12). This is consistent with deepening across the sheet. One Local NTM included two entries that affected this chart within the survey area; notice 33/19 included coordinates and least depths for 2 wrecks in the southern portion of Survey H13223. Both wrecks were reported as DTONS by OSI prior to the notice, and as part of the survey data their shoal soundings were considered in the chart comparison images. US4TX21M80000202018-11-062019-08-19falseENC US4TX21M is the largest-scale chart available for only a small portion of Survey H13223, in the southwestern corner of the survey area. This corner is almost entirely deeper than charted soundings, with some small areas of no change. The magnitude of change was small, approximately 1-2 feet for the majority of the area. No Maritime Boundary Points were assigned for this survey. There were 2 charted wrecks within Survey H13223, both labeled "PA." Both wrecks were disproved with 200% SSS coverage and partial MBES within the assigned search area, and are recommended for deletion from the chart.No uncharted features exist for this survey other than those that were addressed as DTONS. There were 4 DTONS submitted for Survey H13223. No charted shoals were present, and no other potentially hazardous features were observed.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 10 bottom samples acquired in close proximity to the locations assigned in the PRF. Sediment within Survey H13223 was primarily found to be stiff mud and soft mud, with 1 sample also containing shells. See the FFF for details and images of each bottom sample. Shoreline was not assigned in the Hydrographic Survey Project Instructions or Statement of Work.No ATONs exist for this survey.No overhead features exist for this survey.There were 2 charted pipelines within Survey H13223, both of which were assigned in the CSF. Neither pipeline was 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 3 BOEM pipelines within Survey H13223, 2 of which were represented in the ENC and the CSF. The remaining uncharted BOEM pipeline was also not visible in the survey data. 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 H13223.There were 3 charted platforms within Survey H13223, all of which were assigned in the CSF. None of the platforms were found to be present, nor were any uncharted platforms discovered in Survey H13223. 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 H13223. 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 H13223.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