OPR-K379-KR-19Corpus Christi, TX & ApproachesCorpus Christi, TX & ApproachesOcean SurveysH132221Corpus Christi ChannelTexasUnited States50002019John R. BeanNavigable Area2019-03-062019-05-042019-08-30Multibeam 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 May 4, 2019 to August 30, 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 Corpus Christi Shipping Channel, offshore approaches, and surrounding waters. The general locations of the survey limits are presented in Table 1.27.87705297.52651327.78364996.934738Survey 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.Object Detection Coverage (Refer to HSSD Section 5.2.2.2)Objection Detection Coverage was achieved in all accessible areas of Survey H13222 using either Object Detection Multibeam Coverage or 200% side scan sonar coverage with concurrent multibeam, as described in the HSSD Section 5.2.2.2. Given the high vessel traffic, presence of stationary commercial vessels, and ongoing dredging and construction activity in the waters of Survey H13222, access to some assigned survey areas was impeded. OSI received guidance from the COR and made two survey attempts for each impeded area, after which the area was deemed inaccessible (See Appendix II for correspondence). These areas are included in the FFF, marked with a cartographic symbol ($CARTO). 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 H13222 MBES coverage overlaid on a composite of RNCs.file://H13222_Survey-Coverage.jpgR/V H.F. Stout0894.88000695.87053.80R/V Ocean Explorer06.5800000000901.46000695.87053.803.37000024.152019-05-042019-05-052019-05-062019-05-072019-05-082019-05-092019-05-112019-05-122019-05-132019-05-142019-05-152019-05-162019-05-172019-05-192019-05-202019-05-232019-05-242019-05-252019-05-262019-05-272019-05-302019-05-312019-06-012019-06-022019-06-032019-06-042019-06-052019-06-062019-06-072019-06-092019-06-102019-06-112019-06-122019-06-272019-06-282019-06-292019-06-302019-07-012019-07-022019-07-062019-07-072019-07-112019-07-122019-07-132019-07-242019-07-252019-07-262019-07-272019-07-292019-07-302019-08-012019-08-022019-08-052019-08-062019-08-252019-08-30The 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 H.F. Stout "ST"90.76R/V Ocean Explorer "OE"182The survey was conducted employing two vessels, though the majority of Survey H13222 was surveyed using the R/V H.F. Stout. A larger vessel, the R/V Ocean Explorer, was primarily working offshore in other survey areas for this project and collected only a small amount of data within Survey H13222.Teledyne RESONSeaBat 7125 SV2MBESEdgeTech4125SSSEdgeTech4200SSSApplanixPOS 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 3.67% of mainscheme acquisition. All crosslines for Survey H13222 were surveyed by the R/V H.F. Stout. Crosslines were collected on 10 different days within the first month of surveying and were interspersed with mainscheme data collection, though the crosslines were typically the first lines surveyed each time the survey vessel began a new area. Generally, crosslines were oriented to run perpendicular to the channel and mainscheme lines were parallel to the channel directions (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 only 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 of RNCs are in the background.file://H13222_XL_overview.jpgA frequency distribution of the depth differences between the H13222 crossline and mainscheme MBES data. Statistics from the depth difference sample set are displayed above the graph.file://H13222-XL-main-histogram.jpgERS via VDATUM00.098R/V H.F. Stout12R/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 H13222. 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 99.99% of the nodes in this surface meet IHO Order 1 uncertainty specifications. As expected, QC nodes not in compliance with IHO Order 1 uncertainty specifications are found in areas that have features with tall, narrow components, on piers or sheetpile walls, and in areas with steep slopes such as recently dredged areas, channel walls, or shoreline banks.Two current surveys and one prior survey junction with Survey H13222. Figure 4 displays the location of the junction surveys for Project OPR-K379-KR-19, and their details and relative locations 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 H13222. The HSSD defines junction discrepancies requiring further examination as those greater than the TVU * sqrt(2), which for the water depths in Survey H13222 was 0.71m to 0.89m. Survey junctions for Project OPR-K379-KR-19.file://H13222_Junction_Overview.jpgH11246400002005OceaneeringESurvey H11246, an MBES/SSS survey conducted by Oceaneering in 2005, overlaps the eastern end of Survey H13222. Nearly all of the area of Survey H13222 approaching Aransas Pass was also covered by Survey H11246, giving an overlap area of approximately 12 square nautical miles. Survey H11246 was run to achieve 200% sidescan coverage with a set line spacing of 90 meters, while this portion of Survey H13222 was designed to achieve object detection multibeam coverage without use of sidescan data, so the entire region of overlap is covered with current MBES data. A histogram of the depth differences between the two surveys is shown in Figure 5. The median difference was 0.27m, well under the TVU-based discrepancy threshold for Survey H13222. The range of depth differences was broad, though this can be attributed to dredging and sediment movement rather than survey uncertainties or errors. The eastern half of the junction overlap shows very good agreement in depth from 2005 to 2019; bathymetry data farther offshore from Aransas Pass has not shown much change. The Aransas Pass Sea Bar Channel was primarily found to be deeper in 2019 than 2005, on the order of 1-3 meters for much of the length of the channel. South of the channel also showed deepening of 1-2 meters overall, with shoaling of up to 1m in a charted disposal area. Surface-to-surface difference histogram comparing Survey H11246 to H13222.file://H13222-difference-H11246-histogram.jpgH1322450002019Ocean Surveys, Inc.NThe junction with this current survey is discussed in the DR for Survey H13224. H13225100002019Ocean Surveys, Inc.SThe junction with this current survey is discussed in the DR for Survey H13225. 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 6). 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://H13222-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 7 and 8). 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 imagery showing schools of fish in the port channel and the acoustic shadows they casts in the dataset.file://H13222-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://H13222-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 0.5m 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://H13222-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 H13222 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 H13222 was conducted to achieve Object Detection Coverage, using a combination of Object Detection Multibeam Coverage (Option A; HSSD Section 5.2.2.2) or 200% SSS coverage with concurrent MBES (Option B; HSSD Section 5.2.2.2). All potentially significant features located by mainscheme SSS or MBES were also developed with MBES data to meet the Object Detection Multibeam requirements. For single-resolution surfaces, HSSD Section 5.2.2.2 specifies a grid resolution of 0.5m for depths less than 20m and a grid resolution of 1m for depths between 18m and 40m. Water depths in Survey H13222 were surveyed to be between 0.5m and 30m, however, depths deeper than 20m were limited to 2 distinct areas of the survey. One deeper spot was at the Kiewit Shipyard adjacent to La Quinta Channel, and the other was between the Aransas Pass Entrance Jetties and Harbor Island. OSI achieved a high density of coverage on all these areas at a 0.5m grid resolution with no coverage gaps, and so only a 0.5m resolution grid was submitted. 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 0.5m resolution surface meets this requirement, with 99.73% of the nodes in the 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 2019H13222_MB_50cm_MLLW_Final.csarCARIS Raster Surface (CUBE)0.50.55229.487NOAA_0.5mObject DetectionH13222_MB_50cm_MLLW.csarCARIS Raster Surface (CUBE)0.50.55229.487NOAA_0.5mObject DetectionH13222_SSSAB_1m_600and900kHz_1of2.tifSSS Mosaic1N/A100% SSSH13222_SSSAB_1m_600and900kHz_2of2.tifSSS Mosaic1N/A200% SSSIn addition to the surfaces in Table 10, a 0.25m SSS mosaic image composed of all SSS lines was 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.The area covered by H13222 is dynamic and continues to undergo significant change.  Recent and ongoing changes include: post Hurricane Harvey recovery, shoreline and facility development, and channel dredging.  As an alternative to a lengthy text discussion of each chart comparison item, and to assist with the chart comparison review, an annotated image set was compiled to supplement the DR (“H13222_DR_Supplemental.pdf” is included in the DR Report folder and appended to the end of this document).  To create this visual aid, H13222 was divided into 24 areas which are each represented by two figures.  The first figure focuses on channel depths, sounding comparisons, and active dredging; the second figure focuses on features and coverage.  Complete details for individual features are included in the FFF, but items of particular note are emphasized on the visual aid.  The figures reference the largest-scale ENC for the area and include contemporary aerial imagery as a background layer.  Detailed notes with callout markers are organized by the relevant DR sections:  Survey Coverage, Chart Comparison, and Additional Results. The four assigned ENCs covering Survey H13222 that were 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. The only notices during this time concerning Survey H13222 were in the Local NTM 30/19, dated July 24, 2019. The notice gave position and depth information for 3 DTONs identified by OSI, which are addressed in the FFF. US4TX21M80000202018-11-062019-08-19falseENC US4TX21M covers the approach to Port Aransas at the eastern end of this survey area. Refer to the supplemental visual aid Area 19 of 24.US5TX22M40000382019-08-122019-08-12falseENC US5TX22M covers portions of Corpus Christi Channel and La Quinta Channel. Refer to the supplemental visual aid Areas 8-9 and 20-24 of 24. US5TX23M10000232019-07-092019-08-19falseENC US5TX23M covers the Corpus Christi Harbor and the western part of Corpus Christi Channel as it nears the harbor. Refer to the supplemental visual aid Areas 1-8 of 24. US5TX27M20000312019-07-092019-08-12falseUS5TX27M covers Corpus Christi Channel between La Quinta Junction and Aransas Pass, a portion of La Quinta Channel, and around the jetties of Aransas Pass. Refer to the supplemental visual aid Areas 9-19 and 23-24 of 24. No Maritime Boundary Points were assigned for this survey.There were 808 charted features in the CSF within Survey H13222. Over 300 features were verified, most of them ATONs, and other features were disproved or surveyed to be different from charted. There were frequent occurrences of surveyed dolphins that were charted as piles, or dolphins that were observed to be part of a pier and not individual features. For details on charted features, see the FFF and the supplemental visual aid.There were over 200 new features addressed in Survey H13222. Some are repositioned features that were charted too far from their surveyed position, or features that were identified to be different from charted, i.e. dolphins that were charted as piles, but many are previously unidentified features. For details on uncharted features, see the FFF and the supplemental visual aid. The submerged ends of the Aransas Pass entrance jetties are not accurately represented on the chart. In light of an ongoing channel deepening project, revised extents were included in the FFF for these hard features. See Area 18 in the supplemental visual aid for details. There were 14 DTONs submitted for this survey. No other shoals or potentially hazardous features were observed in Survey H13222 outside of those reported to the COR (i.e. surveyed channel depths above controlling depth).The maintained channels in Survey H13222 are: Corpus Christi Channel, Rincon Canal, La Quinta Channel, Dupont Barge Canal, Jewell Fulton Channel, Intracoastal Waterway, Aransas Channel, Port Aransas Channel, and Aransas Pass. A difference surface comparing surveyed depths to channel controlling depths is displayed in the supplemental visual aid, with a callout for each area where surveyed depths were shoaler than channel controlling depths. No bottom samples were acquired for this survey.Shoreline was not assigned in the Hydrographic Survey Project Instructions or Statement of Work.There were 115 ATONs assigned in Survey H13222. The majority of these are on station and serving their intended purpose, but 10 ATONs were found to be missing and 2 were off-station. Missing ATONs were checked against the Light List publication and the Local NTM, and 1 of the missing ATONs was listed in the Local NTM as having been destroyed. The remaining missing ATONs were reported to the USCG via their online reporting tool. Of the 2 ATONs that were off-station, 1 was reported to the USCG via their online reporting tool. The other ATON that was not at its charted position was a sign marking an outfall pipe. The sign was surveyed to be on the position of the pipe, but the charted symbol was 17m distant. The ATON is included at its new position in the FFF and the old position recommended for deletion. There were 2 charted bridges assigned in Survey H13222. The bridge across Corpus Christi Channel at the entrance to Corpus Christi Harbor existed as charted, and the second bridge's location was beyond overhead pipelines with low clearance making it inaccessible for verification. There were also 5 charted overhead pipelines assigned, 2 of which were clearly visible from the accessible survey area. Another pipeline is charted behind these 2 pipelines, but it was not verified as the closer pipelines obscured the view. The remaining 2 assigned overhead pipelines were inaccessible to the survey vessel due to their locations alongside docks occupied with moored vessels at the time of the survey. No unassigned or uncharted bridges or overhead pipelines were found within the accessible survey area. There were 6 charted submarine pipelines located within Survey H13222, none of which were observed to be elevated or exposed. Several pipeline warning signs were found throughout the survey, some of which were near exposed pipelines observed in the data. There were 2 exposed pipes in charted pipeline areas that were noted with warning signs, 1 in the Chemical Turning Basin and 1 in the Aransas Bay to Corpus Christi reach of the Gulf Intracoastal Waterway (GIWW). The exposed pipe in the GIWW also had a danger buoy marking it. There were 2 other areas with warning signs that did not have exposed pipes in the data nearby; 1 near Pelican Island in the Humble Basin to La Quinta Jct reach of the Corpus Christi Channel, and 1 in the Industrial Canal. A warning sign on shore was observed along the Viola Channel marking an uncharted pipeline crossing, and the bathymetry data shows a raised area of the seafloor that is above the channel dredge depth. For details, see the supplemental visual aid. Pipeline data from the Bureau of Ocean Energy Management (BOEM) was also reviewed for potentially uncharted pipelines in the area, but none were identified within the survey bounds.There were 7 charted platforms located within Survey H13222. Of these platforms, 1 was found to be a ruin with structure remnants clearly visible above the water surface, and the other 6 were not present. See the FFF for details on the location of the ruin and the disproval status of the remaining 6 platforms. BOEM Platform data was also reviewed for potentially uncharted platforms in the area, but none were identified within the survey bounds. There was 1 ferry route in Survey H13222 which was confirmed to exist as charted at the time of survey.No abnormal seafloor and/or environmental conditions exist for this survey.Active dredging and shoreline facility construction were observed throughout the survey, with equipment and shoreline changes noted on the surface and bathymetry changes occurring between survey days. For depth changes due to dredging, outdated data were rejected and only the most recent MBES data were accepted and included in the submitted surfaces. Dredge pipes that were recorded in the data are marked in the FFF with cartographic lines ($CARTO). Specific areas of construction or observed changes are detailed in the visual aid. 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