OPR-K375-KR-20Houston, TexasHouston Ship Channel and Galveston BayDavid Evans and AssociatesH133871Upper Houston Ship ChannelTexasUnited States50002020Jonathan L. Dasler, PE, PLS, CHNavigable Area2020-07-022020-08-062021-02-07Multibeam Echo Sounder and Mobile MappingMultibeam 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 15N, 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 Houston, Texas. Survey H13387 was conducted in accordance with the Statement of Work and Hydrographic Survey Project Instructions dated July 2, 2020, and modifications to Project Instructions issued on December 9, 2020, and February 25, 2021. The Hydrographic Survey Project Instructions reference the National Ocean Service (NOS) Hydrographic Surveys Specifications and Deliverables Manual (HSSD) (May 2020) as the technical requirements for this project.29.711773388995.343845694429.80592395.0187823056Survey Limits were surveyed in accordance with the requirements in the Project Instructions and the HSSD.OPR-K375-KR-20 Assigned Survey AreasSupportFiles\OPR-K375-KR-20_Assigned_Survey_Areas.PNGOPR-K375-KR-20 Assigned Mobile Mapping AreasSupportFiles\OPR-K375-KR-20_Scan_Areas.jpgThe purpose of this survey, defined in the Project Instructions, is as follows: “The Port of Houston and the Houston Ship Channel accommodate more than 250 million total tons of cargo each year, ranking it second largest by tonnage in the nation.(1) In 2018, the Port of Houston brought in an estimated $339 billion in value to the State of Texas(2), making it a critical corridor for the economy of the region and nation. The channel itself is maintained by the U.S. Army Corps of Engineers; however, many of the surrounding waterways and bays, which are used by numerous barges, oil services vessels, fishing and pleasure vessels, have not been surveyed in more than fifty years. Modern high-resolution surveys of these areas are important for navigation safety and as a tool to help planners and researchers model and manage issues as diverse as floodwater movement and oyster reef restoration. This current survey covers an area of approximately 79 square nautical miles of Galveston Bay, Houston Ship Channel and Buffalo Bayou. Survey data from this project are intended to supersede all prior survey data in the common area.” 1: Bureau of Transportation Statistics, USDOT: https://www.bts.gov/topics/national-transportation-statistics 2: 2018 Economic Impact of Marine Cargo Activity at the Port of Houston: ExecutiveThe entire survey is adequate to supersede previous data.The channel bottom is continuously changing due to currents, vessel prop wash, dredging activity, construction and/or other factors present in the channel environment. Section B.2.10 of this report further discusses these issues and impacts to the final deliverable data. In all cases the hydrographer has verified that soundings accurately depicted the channel condition at the time of acquisition. All waters in survey areas Sheet 1 and 2Object Detection Coverage (HSSD Section 5.2.2.2)Inshore LimitFor those areas delineated as crane area feature types (CRANES) in the Project Reference File (PRF), navigation limit is the inshore limit of safe navigation for the vessel as determined by the Chief-of-Party. For those area outside of those delineated as CRANES, the inshore limit of hydrography and feature verification for Navigable Area Surveys, the Navigable Area Limit Line (NALL), unless stated otherwise in the Hydrographic Survey Project Instructions, is defined as the most seaward of the following: 1- The surveyed *2.0-meter* depth contour at Mean Lower Low Water (MLLW); 2- The line defined by the distance seaward from the observed Mean High Water (MHW) line, which is equivalent to 0.8 millimeters at the scale of the largest-scale nautical chart covering any portion of the survey area; or 3- The inshore limit of safe navigation for the survey vessel, as determined by the Chief-of-Party. If kelp, rocks, breakers, or other hazards make it unsafe to approach the coast to the limits specified in 1 and 2 above, the NALL shall be defined as the shoreward boundary of the area in which it is safe to survey. Project Instructions called for high-resolution charting at 1:5000 survey scale to support NOAA’s Precision Navigation initiative for the Houston Ship Channel, including: Object Detection Coverage for all waters in the survey area to the 2-meter depth contour or the NALL; verification of Aids to Navigation (ATONs); assignment of shoreline and nearshore features (including bridges, overhead wires, assigned existing terminals, and all uncharted features) to be obtained by a vessel-based mobile laser scanner and delivery of processed laser format (LAS) data referenced using ellipsoidally referenced survey (ERS) methods. Operational challenges included, but were not limited to: conducting surveys in a heavily congested industrial waterway; shoreline surveys in restricted waters with small launch operations in close proximity to terminals, large barge fleets, wrecks, ruins, submerged piles, and numerous snags; dynamic sediment migration; coordinating mapping efforts with ships at berth, ongoing dredging operations; and various navigational trials associated with a heavily trafficked industrial waterway. To mitigate these challenges, and with the volume of shoreline operations required, survey operations were conducted during daylight hours only, automatic identification systems (AIS) and internet vessel tracking systems were utilized, and continuous communications were made to terminal operators and vessel captains by radio and phone. Object detection coverage was obtained over the survey area in depths greater than 2 meters relative to chart datum using 100% multibeam echosounder (MBES) and backscatter unless otherwise discussed in individual sections of this report. This coverage type follows Option A of the Object Detection Coverage requirement specified in Section 5.2.2.2 of the 2020 HSSD. Unavoidable coverage gaps are evident in some areas and are primarily due to large barge fleeting areas. Other factors that blocked or impeded safe vessel operations resulting in data gaps included: berthed vessels that remained during survey operations; low wires behind structures; mooring lines; in-water facilities, and ongoing construction. Significant efforts were expended to maximize coverage to the extent possible in these areas. Section B.2.10 of this report discusses issues restricting this survey coverage in greater detail. Figure 3 depicts the H13387 survey outline. The Project Instructions required the use of mobile laser scanning technology for scanning of bridges, overhead cables, and terminal facilities located in the survey area. These areas, which are depicted in Figure 2 (above), were identified in the PRF as CRANES. Overhead clearances of the assigned bridges and cables, discussed in D.2.3 Overhead Features, were computed from LAS data. Acquisition of mobile lidar data was expanded outside of these assigned areas to encompass the entire survey area in order to facilitate the survey, management, and reporting of all shoreline and nearshore features located within the project area. Additional coverage outside of the planned survey area was obtained east of the Lynchburg Landing as shown in Figure 4. On November 2, 2020, the field party observed tug and barges transiting between the Houston Ship Channel and a fleeting area just east of the Crossover Inbound Range Rear Light. Data were acquired beyond the planned survey extents in this area. The NOAA Project Manager for the survey was informed about the additional survey coverage. H13387 Survey OutlineSupportFiles\H87SurveryCoverage.pngH13387 Additional CoverageSupportFiles\H13387_addtional_coverage.pngS/V Blake0122.36101.800007.110R/V Broughton0193.8527.6000019.830RHIB Sigsbee0284.62000005.6300600.83192.4000032.5705.4200005.312020-08-072020-08-082020-08-092020-08-102020-08-272020-10-052020-10-132020-10-142020-10-152020-10-172020-10-182020-10-192020-10-202020-10-212020-10-222020-10-232020-10-242020-10-252020-10-262020-10-272020-10-292020-10-302020-11-012020-11-022020-11-032020-11-062020-11-082020-11-172020-11-182021-01-302021-01-312021-02-012021-02-022021-02-032021-02-042021-02-052021-02-062021-02-07The OPR-K375-KR-20 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.S/V Blake824.5R/V Broughton242.75RHIB Sigsbee181S/V BlakeSupportFiles\OPR-K375-KR-20_SV Blake.pngR/V Broughton SupportFiles\OPR-K375-KR-20_RV Broughton.jpgRHIB SigsbeeSupportFiles\Sigsbee_Manned.jpgTeledyne RESONSeaBat T50-RMBESRIEGLVMX-450Lidar SystemCarlsonMerlinLidar SystemApplanixPOS MV 320 v5Positioning and Attitude SystemiXblueHydrinsPositioning and Attitude SystemAML OceanographicMicroX SVSound Speed SystemAML OceanographicMVP30-350Sound Speed SystemAML OceanographicBaseX2Sound Speed SystemAML OceanographicSmartXSound Speed SystemTrimbleSPS855Positioning SystemApplanixPOS LV 620Positioning SystemQuality control checks for the mobile lidar system were performed during system mobilization by comparing positions and elevations of scanned features to real-time kinematic (RTK) global navigation satellite system (GNSS) observations. Multibeam crosslines were run across 5.42% 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 50-centimeter CUBE surface encompassing mainscheme, fill, and investigation data for the entire survey area. The QC Report tabular output and plots for all vessels are included in Separate II Crossline Comparison. For the R/V Broughton and RHIB Sigsbee, the output and plot contain data from a dual-head system, with beams 1 to 256 from the port head and 257 to 512 from the starboard head. The S/V Blake is a single-head configuration crossline analysis for 512 beams. 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 50-centimeter resolution CUBE surfaces of mainscheme and crossline depths. Results from the crossline to mainscheme difference analysis are depicted in Figure 8, with units represented in meters. Figure 9 depicts a difference surface portraying the results of sediment migration, active dredging, and shoaling seen throughout the duration of the survey. This figure details crosslines conducted throughout the survey. Change is significant in the dredge and shoaling areas with horizontal differences of up to 1.5 meters occurring between mainscheme and crossline acquisition. In the crossline difference image, overlaid on the final multibeam hillshade, shades of yellow and red indicate shoaling in meters and shades of blue indicate deepening in meters. Shades of gray indicate areas that meet requirements and are generally outside of dredging areas. H13387 Crossline DifferenceSupportFiles\H13387_MB_XL_Only_50cm_MLLW-H13387_MB_MS_Only_50cm_MLLW_depth_delta.pngH13387 Crossline Difference Surface Overlayed on the Multibeam Hillshade, Highlighting Shoaling and DredgingSupportFiles\XL_Diff_2.jpgERS via VDATUM0.050.0906S/V Blaken/a1.0n/a0.5R/V Broughton1.0n/an/a0.5RHIB Sigsbee1.0n/an/a0.5Additional discussion of these parameters is included in the DAPR. Sound speed profiles collected from the R/V Broughton and RHIB Sigsbee were acquired with an AML BaseX or an AML SmartX sound speed sensor. 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 CTD 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 surface are shown in Figure 10. The finalized surface includes occasional large vertical uncertainties that exceed IHO Order 1a allowances. These high uncertainties were caused by introducing areas of high depth standard deviation associated with steep slopes or identified obstructions when finalizing surfaces with the greater-of-the-two option. Node TVU Statistics - 50 centimeters, FinalizedSupportFiles\H13387_MB_50cm_MLLW_Final.QAv6.tvu_qc.pngSurvey H13387 junctions with current survey H13388. No prior surveys were specified as junctions in the Project Instructions. H13388100002020David Evans & Associates, Inc.SAt the time of writing, data from survey H13388 was still being processed. The Descriptive Report for H13388 will include the junction analysis with H13387. Quality control is discussed in detail in Section B of the DAPR. Results from project position checks and multibeam bar checks are included in Separate I Acquisition and Processing Logs of this report. Sound speed checks can be found in Separate II Sound Speed Data Summary of this report. Multibeam data were reviewed at multiple levels of data processing, including: CARIS HIPS conversion, subset editing, and analysis of anomalies revealed in CUBE surfaces.SmartHeave Post-ProcessingDuring the initial setup for RHIB Sigsbee acquisition at the start of the project, a delayed heave message (SmartHeave) was not being output. All Hydrins data collected prior to October 13, 2020, (DN287) were post-processed using DelphINS software. The post-processed solution included the manufacturer’s "smart heave" messages, exported in a custom *.txt file format. All data acquired prior to and including DN287 had the delayed heave file reapplied in CARIS using the GDP application. Post October 13, 2020, a delayed heave message was logged daily to a .log file and applied during processing in Process Designer for all RHIB Sigsbee data acquired for the remainder of survey.Bottom changes during survey operationsChanges in the bottom during survey operations caused misalignments between some sounding data. Three scenarios presented themselves when reviewing data and receiving guidance on processing from HSD Operations Branch: newer sounding data were uniformly shoaler or deeper than previously acquired data; sediment migration caused soundings to be inconsistently shoaler and deeper than overlapping data; and there were areas where overlapping data showed the bottom to be deeper than previously collected survey data due to dredging. In some areas, uniform sediment migration occurred between the acquisition of mainscheme data and subsequent fill and investigation data, causing misalignment between the survey lines. HSD staff provided guidance on this issue, asking that the most recent data in these areas be retained, whether shoaler or deeper, and that older data be rejected in subset editor. After executing, this process contributed to holidays in the deliverable surface. Figure 11 illustrates an example subset view of newer soundings that were uniformly shoaler with older and deeper sounding data that were manually rejected. Impacts from this process that are evident in the deliverable surfaces are highlighted in the H13387_Notes_for_Reviewer.hob file with the cvrage area feature class, submitted in Appendix II of this report. Sediment migration on the seafloor was evident throughout the course of this survey. At times, crossline and fill data acquired after mainscheme hydrography exceeded the allowable uncertainty, with this issue most evident in the vicinity of the San Jacinto River. Following guidance from HSD Operations Branch, the hydrographer allowed the CUBE algorithm to estimate a gridded depth in these areas without manually cleaning the sounding data. Soundings deemed to be fliers were rejected while valid sonar returns were retained, though they may have disagreed with adjacent soundings collected at another time. The submitted surface has numerous artifacts resulting from the areas of disagreement. Figure 12 shows an example of horizontal movement (approximately 80 centimeters) in sediment waves that resulted in disagreement for H13387 bathymetric grids. Some areas of the greatest disagreement have been noted in the H13387_Notes_for_Reviewer.hob file with the SNDWAV area feature class, submitted in Appendix II of this report. This is not an exhaustive list, but highlights major surface artifacts resulting from sediment migration that are present in the bathymetric grids. In some areas, there are notable artifacts in the multibeam data and bathymetric grids resulting from dredging activity. Bathymetric data were collected before, during, and after dredging activities, resulting in large disagreements between overlapping swaths. Following guidance from HSD Operations Branch, when disagreements existed due to dredging, data acquired before dredging were manually rejected to retain newer data acquired after dredging. This practice resulted in the creation of holidays in the bathymetric grids submitted with this survey. Artifacts resulting from dredging and holidays created by rejecting pre-dredge data in the vicinity of the Battleground Oil Specialty Terminal Company (BOSTCO) fuel oil terminal are visible in Figure 13. Guidance from HSD is included in Appendix II of this report.Sediment Migration ArtifactsSupportFiles\Rejection_of_deeper_soundings.jpgSediment Migration ArtifactsSupportFiles\sediment_wave_disagreement.jpgPost-Dredge Surface HolidaysSupportFiles\H13387_Coverage_gaps_from_post_dredge_depths.pngApproximately 1-hour intervals For H13387 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 one-hour interval for S/V Blake and R/V Broughton. The RHIB Sigsbee moved around more frequently acquiring data along the shoreline, which required the application of sound speed casts in CARIS using the nearest in distance within a two-hour interval. The deviation from one hour to two hours between casts had no discernible impact on data quality as casts were relatively consistent. Additional discussion of sound speed methods and equipment can be found in the DAPR. All cast profiles were made within 500 meters of the survey limits. Data collected by the RHIB Sigsbee on November 1, 2020, (DN306) were processed with sound speed profiles acquired by the R/V Broughton, which operated in the same area.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, barge fleeting, ships at berth, ongoing construction, or other factors. Details impacting survey coverage are detailed in section B.2.10. Mobile lidar coverage was obtained on assigned overhead features and along the shoreline within the scan area. Mobile lidar was also acquired outside of the scan areas to aid in the positioning of baring features. 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 Figure 14. Node Density Statistics - 50 centimeters, Finalized SupportFiles\H13387_MB_50cm_MLLW_Final.QAv6.density.pngData Gaps in Bathymetric CoverageOccasional data gaps in the final Object Detection surface exist due to operational restrictions at the time of survey. These data gaps were further analyzed after acquisition and determined to be unattainable due to safety or other factors impacting vessel operations. Significant effort was expended during survey operations to maximize object detection coverage in these areas. Some of the sources for these data gaps include, but are not limited to: - Holidays or 2-meter coverage gaps behind pier structures where the field unit was physically unable to operate, or safety concerns limited access. - Holidays or 2-meter coverage gaps underneath barge fleets or ships at berth. These were revisited at least one additional time on subsequent days. Typically, the field hydrographer would acquire data along the achievable extents of the gap and document the existence of barge fleet or vessel with positioned targets and/or photos. AIS or internet-based vessel tracking tools were used to alert the field unit when vessels were underway. - Holidays or 2-meter curve (NALL), which were not further investigated due to safety concerns in shallow water. - Holidays created beneath baring structures that met the area requirements were rejected in the survey area for final delivery. - Holidays created from rejecting data acquired before dredging when overlap between pre- and post-dredge data existed (see section B.2.6 for detail). Holidays that exist in the final surface have been noted in the H13387_Notes_for_Reviewer.hob with the cvrage area feature class, submitted in Appendix II, and attributed with remarks stating the contributing factor leading to the data gap. Areas where the assigned 2-meter inshore limit was not met included in the H13387_Notes_for_Reviewer.hob with brkline features. SNDWAV features were also delineated, noting where sediment movement was observed and resulted in artifacts in the surface. Figures 15 and 16 detail examples of coverage gaps in deliverable data. Example of Holidays Created from Rejecting MBES Data on or Under Baring FeaturesSupportFiles\H13387_Coverage_gaps_baring_structures.pngExample of Holidays Resulting from Barge FleetsSupportFiles\H13387_Coverage_gaps_inaccessibility_barge_fleets.pngData reduction procedures for survey H13387 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 H13387 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 2020v3A detailed listing of all data processing software is included in the OPR-K375-KR-20 DAPR.H13387_MB_50cm_MLLWCARIS Raster Surface (CUBE)0.50.03219.372NOAA_0.5mObject Detection MBESH13387_MB_50cm_MLLW_FinalCARIS Raster Surface (CUBE)0.50.03219.372NOAA_0.5mFinalized Object Detection MBESBathymetric grids were created relative to MLLW in CUBE format using Object Detection resolution requirements as specified in the HSSD. CARIS HDCS Navigation Sources During processing of S/V Blake and R/V Broughton HDCS lines, navigation information (delayed heave, motion and RMS values) was imported from POS M/V .000 files. This navigation source, Applanix.ApplanixGroup1, is automatically applied at georeference when it exists. When a line is renamed, such as with a suffix _XL, the HDCS navSource disappears from the metadata display. This appears to be a display issue only and does not change any navigation sources. Mobile Lidar Data Two laser systems were used during acquisition within sheet H13387. A vessel-based Mobile Mapping System (MMS) mobilized on the S/V Blake was used to acquire lidar and imagery data primarily within the assigned scan areas. A secondary laser scanner mounted on the R/V Broughton was used to acquire fill data where gaps in coverage may have been left as a result of vessels being at berth or to add to laser coverage outside of the assigned scan areas in order to facilitate the management and reporting of shoreline and nearshore features. Processed LAS data from the MMS and laser scanner are included with the survey deliverables in the Processed directory. Imagery data collected by the MMS were used for feature interpretation during processing. Photos of individual features were extracted from the imagery data or taken during hydrographic survey operations and populated using the “images” attribute in the Final Feature File (FFF).Surface Finalizing Not Honoring Designated SoundingsQC checks on the finalized surface using Pydro QCTools (VALSOU Check) identified three locations where designated soundings were not being applied during surface finalization in HIPS. After consultation with Teledyne CARIS, it was determined that a software issue was present. On June 6, 2021, a software fix was provided in a HIPS beta release to be used specifically for finalizing surfaces. After basic testing using nonproduction data, the HIPS beta release was used to finalize the original bathymetric surface for survey H13387. Upon completion, the finalized surface was checked for outstanding issues using Pydro QCTools (VALSOU Check) and the previous issues were no longer identified. Also, the original finalized surface was differenced with the finalized surface created with the beta. The only differences occurred at the three locations where the designated soundings weren't being applied in the original finalized surface. The surface finalization fix will be included in the 11.3.20 official release of HIPS. At the time of this survey delivery to NOAA, a release date for HIPS 11.3.20 had not been determined.Final Feature File using NOAA Rename FFF Images per HTD ToolAfter using the Rename FFF Images per HTD Tool in Pydro Explorer to rename feature images to meet HSSD requirements, it was discovered that over 700 features (points, lines, and areas) in the output .000 file were no longer precisely coincident with the original feature positions. In all cases, the horizontal position differences between the input and output files were found to be less than 1 centimeter. There was no change in elevations or depths reported in the FFF. After consulting with NOAA Operations Branch Staff, DEA received permission to submit the FFF produced by the Rename FFF Images per HTD Tool as long as the horizontal distance between the original feature and the feature output from the tool were less than 2 centimeters. The H13387 survey submission includes the original FFF and images prior to renaming as well as the FFF and images output from the renaming tool. Files were placed in separate subfolders on the delivery drive following guidance from NOAA Operations Branch. The use of subfolders may be flagged when running checks against the standard HSSD Data Directory Structure template. The number of original images and the number renamed images do not match as some images were attributed to more than one feature in the original FFF. Correspondence related to this issue is included in Appendix II.   The cause of the issue, other than be related to the use of the Rename FFF Images per HTD Tool, was unknown at the time of submittal.A summary of the horizontal and vertical control for survey H13387 follows.Mean Lower Low WaterERS via VDATUMOPR-K375-KR-20_VDatum_NAD83-MLLW_Geoid18.csarOPR-K375-KR-20_VDatum_NAD83-MHW_Geoid18.csarThe MLLW version of the separation file was used to reduce all sounding data to the MLLW chart datum for the survey area. The MHW version of the file was used to transform all mobile laser data to mean high water, the high-water chart datum for the survey area. Both files were provided by the HSD for use on this survey project.North American Datum 1983Projected UTM 15Smart BaseAn RTK-corrected real-time navigation solution was used during processing of multibeam data unless data quality or correction reception issues impacted the accuracy of the position or height data. This determination was made by reviewing acquisition logs for loss of RTK corrections or operating outside of fixed ambiguity mode as noted by the field party or logged by the HYPACK acquisition system, observing inconsistent global positioning system (GPS) heights when reviewing data in the CARIS HIPS Attitude editor, or the presence of significant GPS tides artifacts in bathymetric surfaces. When issues with the real-time navigation solutions were identified in a survey line, all survey lines acquired by the survey vessel on the day in question were post-processed using post-processed kinematic (PPK) methods. The post-processing methodology and software used was determined by the navigation system on each survey vessel. Applanix POSPac MMS was used to post process navigation solutions for survey vessels S/V Blake and R/V Broughton, which used POS MV OceanMaster GNSS inertial reference systems. Novetel GrafNav software was used to post-process navigation data from the RHIB Sigsbee, which used a Trimble GNSS receiver integrated with an iXBlue Hydrins. Texas Department of Transportation (TxDOT) Real Time Network (RTN) base station data and published NAD83 (2011) base station positions were used during post-processing. See Section C.4 of the DAPR for additional discussion on post-processed positioning. The following days for survey H13387 have post-processed solutions applied: S/V Blake: October 21, 2020 (DN295); R/V Broughton: November 1, 2020 (DN306), January 31, 2021 (DN031), February 1, 2021 (DN032), February 3, 2021 (DN034), February 4, 2021 (DN035), February 5, 2021 (DN036); RHIB Sigsbee: October 15, 2020 (DN289), October 17, 2020 (DN291), October 18, 2020 (DN292), October 19, 2020 (DN293), October 23, 2020 (DN297), October 24, 2020 (DN298), October 25, 2020 (DN299), October 27, 2020 (DN301), November 1, 2020 (DN306). During acquisition, RTK correctors were obtained from the TxDOT RTN via a dedicated cellular modem. These correctors provided RTK level of accuracy for horizontal and vertical positions for all survey data. When issues with the real-time navigation solutions were identified in a survey line, all survey lines acquired by the survey vessel on the day in question were post-processed. Additional discussion of the TxDOT network, including quality control checks and acquisition and processing procedures, is discussed in the DAPR.Water Level FloatsWater level floats were conducted by the field unit at the location of NOAA National Water Level Observation Network (NWLON) gauges within the OPR-K375-KR-20 project area. Methods, analysis, and results of these floats are further documented in the DAPR. The chart comparison was performed by comparing H13387 survey depths to digital surface generated from the band 5 electronic navigational charts (ENCs) covering the survey area. A 10-meter product surface was generated from a triangular irregular network (TIN) created from the ENC’s soundings, depth contours, and depth features. An additional 10-meter HIPS product surface of the entire survey area was generated from the 50-centimeter 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 band 5 ENCs used in the cart comparison are listed in Table 13. Figures 17 through 25 show the magnitude of differences along the comparison area. H13387 to Band 5 ENC Depth Difference, Area 1 of 9SupportFiles\H13387_Chart_comp_US5_1.pngH13387 to Band 5 ENC Depth Difference, Area 2 of 9SupportFiles\H13387_Chart_comp_US5_2.pngH13387 to Band 5 ENC Depth Difference, Area 3 of 9SupportFiles\H13387_Chart_comp_US5_3.pngH13387 to Band 5 ENC Depth Difference, Area 4 of 9SupportFiles\H13387_Chart_comp_US5_4.pngH13387 to Band 5 ENC Depth Difference, Area 5 of 9SupportFiles\H13387_Chart_comp_US5_5.pngH13387 to Band 5 ENC Depth Difference, Area 6 of 9SupportFiles\H13387_Chart_comp_US5_6.pngH13387 to Band 5 ENC Depth Difference, Area 7 of 9SupportFiles\H13387_Chart_comp_US5_7.pngH13387 to Band 5 ENC Depth Difference, Area 8 of 9SupportFiles\H13387_Chart_comp_US5_8.pngH13387 to Band 5 ENC Depth Difference, Area 9 of 9SupportFiles\H13387_Chart_comp_US5_9.pngUS5HOUEB1000012021-01-262021-01-26US5HOUEC1000022021-03-252021-03-25US5HOUED1000022021-03-252021-03-25US5HOUEE1000052021-03-252021-03-25US5HOUEF1000022021-03-252021-03-25US5HOUEG1000012020-03-112020-03-11US5HOUFF1000022020-08-062020-08-06One Danger to Navigation (DtoN) report was submitted for this survey on November 17, 2020. - Survey H13387 DtoN 1 reported an uncharted obstruction in the San Jacinto River. This feature has been added to the charts using preliminary survey information.Numerous charted features exist within the limits of Sheet H13387. All assigned features included in the project Composite Source File (CSF) have been addressed by the survey and are included in the FFF. Due to the large scale of the survey (1:5000), many charted features have been recommended for deletion to be replaced by new higher-resolution features digitized from the survey data. All disproved features have been included in the FFF with a description of "Delete". All new features have been included in the FFF depicting the feature surveyed and with a description "New". The FFF includes assigned features, both baring and submerged, charted shoreward of the NALL that were too hazardous to survey. The baring features were either beyond the detection range of the MMS or obscured by vessel traffic, such as moored vessels or barge fleets. Multiple unsuccessful attempts were made to detect these outstanding obscured features. These features are included in the FFF with a description of "Not Addressed". All uncharted features are portrayed in the FFF as surveyed and attributed with the description of "New". Refer to the FFF for additional information. During collection of the perpendicular investigation pass to verify the least depth of an uncharted obstruction in the vicinity of Sims Bayou, the field team observed that the feature had moved approximately seven meters from the first surveyed position. The feature originally observed during mainscheme acquisition was rejected in subset editor, and the most recent position of the obstruction is included in the FFF with remarks detailing the movement of the uncharted obstruction. Figure 26 shows CARIS subset editor with the rejected soundings (in grey) and the current position, identified in MBES, of the feature. Any other features that moved after mainscheme acquisition are noted in the FFF remarks.Unique Feature in FFFSupportFiles\H87_B_35_info.jpgThe survey area included multiple channels portrayed on the ENCs as dredged area features (DRGARE). These include federal channels maintained by the United States Army Corps of Engineers (USACE) and other private channels maintained by Port Houston. Figures 27 and 28 list the minimum surveyed depth within each named channel quarter, along with the corresponding ENC channel depth and USACE-authorized channel depth. During survey operations, multiple surveyed soundings found to be shoaler than channel controlling depths were reported to the Atlantic Hydrographic Branch (AHB). Copies of these submissions and associated correspondence are included in Appendix II. During the chart review, DEA discovered an error in the DRVAL1 depths charted on ENC US5HOUEF in the Carpenter Bayou to Boggy Bayou reach of the Houston Ship Channel. The issue was reported to the Marine Chart Division through the MCD Assist website (NOAA Coast Survey Customer Response for Ticket #262407). It appeared that the depths for these reaches were not converted from feet to meters before attributing the ENC. This issue is apparent in the chart comparison difference surface depicted in Figures 18 and 19 (above). Email correspondence related to this issue is included in Appendix II.Channel Results page 1SupportFiles\H87_Channels_Page_1.pngChannel Results page 2SupportFiles\H87_Channels_Page_2.pngAids to Navigation (AtoNs) were investigated using mobile lidar and visual observations. AtoNs that were missing, damaged, or not serving their intended purpose were reported to USCG via email on March 29, 2021. A copy of the email submittal is included in Appendix II. AtoNs have been included in the sheet’s FFF with appropriate comments and recommendations. No Maritime Boundary Points were assigned for this survey.No bottom samples were required for this survey.Both the Raster Nautical Chart (RNC) and ENC for this area include charted clearance heights for bridges and cables. The charted heights for all overhead features match within a decimeter between the RNC and ENC. Both note the vertical datum as MHW. For the assigned cables and bridges inside scan areas, overhead clearances were determined using LAS data acquired with the RIEGL VMX-450 mobile mapping system using ERS methods and the NOAA-provided custom separation model. All clearances were determined relative to MHW. D.2.4.1 Overhead Cables and Pipes Clearance on overhead cables was determined by using CARIS Base Editor to identify the valid LAS point with the lowest elevation at each cable crossing. Because the LAS data often extended onto shore, the search area was limited to the portion of the cable spanning navigable water. Within H13387, there are four assigned laser scan areas that cover four assigned overhead cables. For the purpose of the report these are considered major overhead cables. Overhead clearance for an additional cable that was not within an assigned scan area at the mouth of the San Jacinto River was also determined. The surveyed major overhead cable clearances are summarized in Figure 29. Outside of the scan areas, there are an additional 18 overhead cables and 17 overhead pipes that have been assigned and have an investigation requirement of "visually confirm" only. For the purpose of the report, these are considered minor overhead cables. Of the 30 minor overhead cables, 20 were observed, 6 were not observed, and 4 were not addressed as they were well beyond the NALL or their location was obscured from view. Of the 18 minor overhead pipes, 13 were observed, 4 were not observed, and 1 was not addressed as is it was well beyond the NALL. These features are included in the FFF. D.2.4.2 Bridge Clearance Analysis Within H13387, two assigned scan areas cover bridges. The Sam Houston and Sidney Sherman bridges were evaluated using the Bridge Clearance Analysis procedure outlined in the DAPR. The following figures depict an elevation view of each bridge, bridge segments colored by minimum elevation, and lights and other hanging features below the bridge decks that are included in the FFF. Also included is a diagram published in the “Mariner Guide Navigating the Houston-Galveston Area Waterways,” listing published clearances for each bridge. All figures below depict views of bridges looking up the channel. Surveyed Major Overhead Cable ClearancesSupportFiles\Overhead_Cable_Clearances.jpgPublished Bridge Clearances in Height Above MHWSupportFiles\Published_Bridge_Clearances_MHW.pngSidney Sherman Bridge ClearanceSupportFiles\H13387_SidneySherman_FTB.pngSam Houston Bridge ClearanceSupportFiles\H13387_SamHouston_FTB.pngSubmerged pipelines, submerged pipeline areas, and submerged cable areas, where anchoring, trawling, and dragging are restricted, are charted within the survey area. When within the NALL, these precautionary areas and features were surveyed using object detection MBES coverage and carefully reviewed for any pipelines or cables that were exposed and posing a risk to navigation. A linear feature observed in the MBES data within the charted pipeline area in Sims Bayou, which appeared to be an exposed pipeline, was reported to the Texas General Land Office (TxGLO) following guidance received from HSD Operations Branch. A copy of this report, which was submitted in lieu of the Bureau of Safety and Environmental Enforcement (BSEE) pipeline report described in the HSSD, is included in Appendix II. This feature was also reported to AHB following the Non-Dangerous Pipeline Reporting process. A copy of the email submission is included in Appendix II. See the H13387 FFF for more details. A ferry route crossing the Houston Ship Channel is charted on ENC US5HOUEF. According to the Harris County Toll Road Authority, this is the Lynchburg Ferry. No object name attribute is charted for this ferry route. The hydrographer recommends adding the route name to the ENC. No abnormal seafloor and/or environmental conditions exist for this survey.Construction and dredging are common occurrences in the Houston Ship Channel. Dredging activities were observed at the BOSTCO terminal during survey operations with impacts to survey coverage and data quality discussed in Section B.2.6. Construction was observed at the north and south terminals of the Lynchburg Ferry during survey operations. The construction did not impact survey operations.Plans are underway for a significant channel expansion project, known as Project 11, which will deepen and widen the Houston Ship Channel. The hydrographer recommends resurveying the area impacted by the expansion project with Object Detection Coverage upon completion. 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 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 Party2021-06-21Jason Creech, CHNSPS/THSOA Certified Hydrographer, Charting Manager / Project Manager2021-06-21Callan McGriff, EITIHO Cat-A Hydrographer, Lead Hydrographer2021-06-21James GuilfordIHO Cat-A Hydrographer, Lead Hydrographer2021-06-21Michael RedmayneIHO Cat-A Hydrographer, Lead Hydrographer2021-06-21Data Acquisition and Processing Report2021-06-22