OPR-K414-NRT4-NRT4-17Galveston Bay and VicinityCentral Galveston BayNavigation Response Team 4H123921The regional Navigation Manager has received pilot and port authority requests for hydrographic surveys in Galveston Bay and vicinity. The main purpose of this project is to survey the newly charted barge channels along the main Houston Ship Channel. This survey is intended to supersede all bathymetry, seafloor features, and bottom characteristics within the assigned survey area as defined by these instructions for updating of NOAA charts 11327 and 11328.Central Galveston BayTexasUnited States100002017Dan JacobsNavigable Area2017-07-072017-08-232018-01-31Kongsberg EM2040C Multibeam EchosounderEdgetech 4125 Side Scan Sonarmetersnsverse Mercator (UTM)UTCPacific Hydrographic BranchH12392 Mulitbeam Sonar concurrent with Side Scan Sonar data collection (i.e. Skunk Striping) began in August, 2017. However, two weeks into the project NRT4 survey assets and priorities abruptly shifted to hurricane response operations in Texas, Florida and Mississippi. Unprecedented flooding in the greater Houston Region had doubtlessly changed the depths in Galveston Bay as a result of Hurricane Harvey. In November 2017, NRB proposed NRT4 assess the feasibility of salvaging and submitting some of the H12392 pre-hurricane soundings by rerunning an original argyle cross line and performing a surface difference analysis. Results of this analysis showed the Houston Ship Channel and its abutting edges to the barge lanes had seen significant change but that the soundings/imagery in the barge lanes proper were in closer (95 percent IHO confidence level) agreement Thus, it was decided NRT4's course of action would be to acquire soundings/imagery in the barge lanes wherever necessary but exclude the Houston Ship Channel altogether on account of increasingly foul, winter weather.NOAAThis object detection survey was accomplished with 200 percent side scan sonar coverage concurrent with object detection, MBES bathymetry. Operations commenced on DN345 (2017) and concluded on DN031 (2018). 29.61219394.95337529.48887594.865225H12392 Survey Sheet Limits (green dashed line), Chart 11327, 47 Ed.file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/H12392_sheet_limits.PNGNRT4 did not obtain total object detection coverage to the sheet limits of H12392. Shoals adjacent to commercial shipping traffic generated considerable wakes which precluded a safe approach and/or suitable sea state for surveying, particularly near Red Fish Island Shoal. Likewise, frequent barge, tanker and commercial fishing traffic all prevented comprehensive, object detection coverage in the vicinity of the Bulkhead Reef spoil area (northern end of the sheet). Areas of missed Side Scan coverage are outlined in Figures 2-10 shown below.Index of H12392 100% SSS missed coverage, Chart 11237file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_1.PNG100% SSS missed coverage, Inset 1file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_2.PNG100% SSS missed coverage, Inset 2file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_3.PNG100% SSS missed coverage, Inset 3file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_4.PNG100% SSS missed coverage, Inset 4file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_5.PNGIndex of H12392 200% SSS missed coverage, Chart 11237file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_6.PNG200% SSS missed coverage, Inset 1file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_7.PNG200% SSS missed coverage, Inset 2file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_8.PNG200% SSS missed coverage, Inset 3file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Coverage_9.PNGThe regional Navigation Manager has received pilot and port authority requests for hydrographic surveys in Galveston Bay and vicinity. The main purpose of this project is to survey the newly charted barge channels along the main Houston Ship Channel. This survey is intended to supersede all bathymetry, seafloor features, and bottom characteristics within the assigned survey area as defined by these instructions for updating of NOAA charts 11327 and 11328.The entire survey is adequate to supersede previous data.At the 95 percent confidence interval, the entire survey is adequate to supersede previous data.Using Argyle Pattern Crossline, (i.e. zig-zag pattern) seek the 9 foot curve, per project instructions.Object DetectionCommercial shipping traffic, commercial fishing operations and inclement winter weather (fog, ice, high winds and unfavorable sea states) all precluded 100 percent object detection coverage to the sheet limits of H12392 during this late field season project. NRT4 focused hydrography to barge lanes in an effort to capture the essence of the project's stated purpose "to survey the newly charted barge channels along the main Houston Ship Channel" per the project's registry instructions. Please reference A.1 of this Descriptive Report for specific areas where object detection Side Scan Sonar coverage were not obtained.H12392 MBES Coverage, Chart 11327file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Coverage%20Graphic.PNGS30080000014001400000013901401000002.42017-11-302018-01-31Data collection for H12392 originally began on DN223 (11AUG2017) through DN236 (24AUG2017). Survey operations were interrupted as Hurricane Harvey entered Texas waters. Reacquisition for H12392 recommenced on DN334 (30NOV2017) and concluded on DN031 (31JAN2018) because pre hurricane data exhibited poor agreement with these more recent soundings. Pre hurricane SSS/MBES lines totaled 125 Linear Nautical Miles and were not included in the project submission folder.Refer to the Data Acquisition and Processing Report (DAPR) for a complete description of data acquisition and processing systems, survey vessels, quality control procedures and data processing methods. Additional information to supplement sounding and survey data, and any deviations from the DAPR are discussed in the following sections.S3008100.5S3008file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Best_Boat.JPGS008 is an aluminum survey vessel manufactured by Lake Assault Boats of Duluth, MN. It was assigned to NRT4 in the Fall of 2016 and was integrated with a hull mounted multibeam sonar and pole mounted side scan sonar in the weeks preceding the 2017 Field Season. The vessel is approximately 34 feet in length with a beam of 8 feet and a draft 1.6 feet. Its powered by two Honda 225 HP outboard engines. A side scan winch and davit are installed and configurable for either port or starboard gunnel deployment just ahead of the stern. Additionally, a pole mount my be installed via hardware and tooling plates built onto the port and starboard gunwales amidship. The vessel may accommodate up to 4 persons and typically sees operation in bays and harbors where depths are between 4 to 50 meters. EdgeTech4125SSSKongsberg MaritimeEM 2040CMBESPlease reference NRT4's 2017 DAPR for equipment specifications.The crosslines for H12392 were collected in an "argyle" zig-zag pattern transecting the edge of the sheet limit polygon to approximately 3 meters depth. This method, prescribed by the Pacific Hydrographic Branch will aid cartographers in determining up-to-date depth contours flanking the Houston Ship Channel and adjoining barge lanes. 10 percent (14 linear nautical miles) of crossline miles were acquired as compared to main scheme miles (140 linear nautical miles). 0.0900.00TCARIS30084.00.01.0Tide uncertainty for the project area was 0.09 meters at one sigma. This value was doubled to 0.18 meters during TPU calculation as CARIS outputs a two sigma value. Total Vertical Uncertainty (TVU) calculation was calculated via Pydro's Grid QA tool. The finalized grid passed with better than 99 percent of grid nodes falling inside the IHO Order 1a error budget. Similarly, the survey's object detection sounding density requirements were satisfied as 99 percent of finalized, 50cm grid nodes contained at least 5 soundings per node. See uncertainty graphs, below.TCARI Uncertaintyfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Tide_Error_grab.PNGTotal Vertical Uncertainty calculation for H12392 Finalized CUBE Surfacefile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/H12392_MB_50cm_MLLW_Final.QAv5.tvu_qc.pngSoundings Density Statistics for H12392 Finalized CUBE Surface.file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/H12392_MB_50cm_MLLW_Final.QAv5.density.pngH12392 50cm grid nodes were compared to historic (2013) H12391 50cm grid nodes invoking the Pydro Surface Difference Tool. The overlapping nodes did not meet IHO specifications as only 85 percent passed the allowable error fraction. Sounding disagreement is common from year to year in this waterway as sedimentation from numerous rivers and bayous is constantly occurring. Consequently, a four year lapse between adjoining surveys and a major flooding event (Hurricane Harvey) both likely contributed to this sounding comparison discrepancy. Moreover, the USACE and Houston Pilots are cognizant of this shoaling and contract dredging operations are nearly continuous throughout the bay.50cm Overlap Difference Surface, H12392 minus H12391file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/H12392_MB_50cm_MLLW_Final-H12391_MB_50cm_MLLW_1of1_fracAllowErr_Freq.pngSonar system quality control checks were conducted as detailed in the quality control section of the DAPR.Bubble Sweep ArtifactsBubble Sweep Artifacts we observed throughout the survey. Although the noise artifact has historically been more prevalent in heavier seas (15 knot plus winds), this issue seemed to persist even in relatively calmer sea states (5-10 knot winds). Despite the Hydrographer's best efforts to mitigate the noise (e.g. adjust frequency to from 300 to 200 kHz and vessel speed) bubble sweep artifacts required extensive manual cleaning during post processing in CARIS Subset Editor. NRB is investigating modification of the sonar blister mounts and hull chines on each of its NRT boats to diminish such noise.Bubble Sweep Artifactsfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/bubble%20sweep.PNGSSS Banding ArtifactWhite bands across the side scan data were recorded throughout the survey. It was found that when the survey speed was reduced to <4 knots the banding mostly went away. It is believed that the banding was a direct result of the sonar limitations and extreme vessel motion brought on because the side scan sonar was pole mounted. Since post processing does not change the imagery, there was nothing further that could be done for the side scan data that was already collected. Further investigation will be done before data is collected in the future. Banding artifacts were most pronounced on DN235, DN345, and DN347.SSS Banding Artifactfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/SSS_Artifact2b.JPGFluid Mud LayerA fluid mud layer is know to exist just above a firm mud bottom owing to numerous bayous draining into Galveston Bay. Shipping traffic propulsion and shrimp trawling operations generated turbidity plumes from this fluid mud layer some of the time. Soundings/Imagery had to be reaquired on several occasions due to this factor. Sedimentation from numerous rivers and bayous upstream of Galveston Bay is constantly occurring in this waterway. USACE and Houston Pilots are cognizant of this shoaling and contract dredging operations are continuous somewhere in the bay on any given day.Sound Velocity At times, outer beam soundings were effected by inaccurate sound speed modeling throughout the water column, evident by their "frowning" or falling away from an otherwise collinear bottom trace. Such data were deleted in post processing when influencing the CUBE surface."Frowning" sound speed artifactfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/frown.JPGThe "frowning" effect is more likely due to MBES fliers, as the remaining data represents a well formed seabed. These edge fliers have been removed from the dataset.Sound speed casts were taken every 4 hours IAW 2014 NOAA FPM.Sound speed casts were processed in Pydro's Sound Speed Manager and applied to soundings during post processing implementing the "Nearest in Distance, Within Time" option in CARIS 10.NRT4 attained object detection coverage by collecting 200 percent SSS coverage logged concurrently with MBES. Numerous SSS Lines were named with the suffix "_Fill" where additional SSS coverage was required due to substandard bottom trace. This unconventional, yet practical naming scheme was given approval by NSD's Project Manager. His approval email pertaining to the matter may be found in the project correspondence folder. All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.TPU Offsets Error and Waterline Error Discovered after SARPHB discovered erroneous null entries in NRT4's Multibeam HVF/TPU Offsets during SAR. There had been previous discussion on this topic between Team Lead and NRB folks however it was thought at that time that these values should be zero. Subsequent to the project's resubmission, NRT4 populated the HVF's "MRU-Trans" and "NAV-Trans" offset entries and their associated error values. This way, a valid TPU calculation could occur to those offsets. Additionally, Team Lead had accounted for the waterline measurement in Seafloor Information Systems (SIS) but was unaware this value (-0.51m) also required an HVF entry. NRT4 made these necessary offset changes to the multibeam sonar's HVF, re SVP'd, re merged the data and recomputed TPU. The 50cm finalized surface passed its IHO test above the 99 CI. Accordingly, these values were also changed for the 2017 DAPR accompanying this report. All correspondence pertaining to these matters have been documented in the Project Correspondence folder.TPU Offsets and Waterline missing from HVFfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/TPU_Offsets_Error_Discovered.JPGBackscatter was not collected for this survey.CARIS_Support_Files_Ver_5_6NRT4 updated all processing computer support files with new version (5.6) name in September, 2017.H12392_MBES_50cm_MLLW_FinalCARIS Raster Surface (CUBE)0.50.3316.11NOAA_0.5mObject DetectionH12392_SSSAB_1m_400kHz_1of2SSS Mosaic11.5616.83N/A100% SSSH12392_SSSAB_1m_400kHz_2of2SSS Mosaic11.5616.83N/A200% SSSThe finalized 1m CUBE SSS Mosaic, a 100 percent and a 200 percent side scan mosaic were generated in accordance with 2014 Field Procedures Manual, Paragraph 4.2.1.1.Non-standard SSS Line Naming ConventionNumerous SSS Lines were named with the suffix "_Fill" where additional SSS coverage was required due to substandard bottom trace. This unconventional, yet practical naming scheme was given approval by NSD's Project Manager. His approval email pertaining to the matter may be found in the project correspondence folder. Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR.Mean Lower Low WaterTCARI8770613.tidFinal Approved8771013.tidFinal Approved8771341.tidFinal Approved8771450.tidFinal ApprovedK414NRT42017.tcFinal2018-02-012018-02-13Final TCARI tides were requested on February 1, 2018 and received on February 13, 2018. The preliminary TCARI grid was accepted as the final grid for H12392. Please reference the Final Tide NOTE in the Descriptive Report's Appendices folder.North American Datum 1983UTM Zone 15NThe Differential GPS (DGPS) beacon in Angleton, TX broadcasting at 301 KHz was employed for horizontal control of all survey lines for H12392.A chart comparison was performed in CARIS 10 by use of a survey sounding overlay in US Survey Feet atop NOAA Chart 11327 charted soundings. A font size of 10 with a suppression radius of 75 meters was chosen for a map scale of 10000. The resulting survey soundings were similarly sized to charted soundings at a 1:10000 scale but nearly 3 times the density/spacing. The Hydrographer deemed these settings adequate for a generalized comparison between survey depths and charted soundings. 1132725000382018-03-242018-03-27trueNotable differences between survey depths and charted sounding are listed below. Inset 1 charted soundings were within two feet of survey depths with a deepening trend evident near the west side of Bulkhead Reef. Inset 2 survey soundings exhibited a deeper trend by about 2 feet along Bulkhead Reef. Inset 3 had two (2) soundings deeper than charted and a 6 foot shoal (blue tint) which likely has reduced in dimension, though not entirely esonified. These northern reaches of Chart 11327 aside, depths in were good agreement overall, not differing by more than 2 or3 feet from charted.Inset 1, Sounding Comparisonfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Inset1_for_DR.PNGInset 2, Sounding Comparisonfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Inset2_for_DR.PNGInset 3, Sounding Comparisonfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Inset3_for_DR.PNGNo Maritime Boundary Points were assigned for this survey. Two assigned features contained the label "PA" for H12392. Neither were seen in object detection MBES data or 200 SSS imagery.2 "PA" features not seen, shown inside yellow callout box.file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/PA_Objects_not_seen_final.PNGNew features exist, were investigated and are included in the Final Feature File (FFF) accompanying this project. The features appear to be remnants of piles or footings belonging to structures and signage that no longer exist. The new features do not pose a danger to navigation based on their similar height to surrounding depths or are situated below the controlling depth of barge lanes (12 feet).New feature, added to FFF.file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/OBST_New_6A.PNGNo shoals or potentially hazardous features exist for this survey. Designated soundings lacking feature correlation to the FFF were created in consequence to the CUBE surface not honoring the shoalest point on the seafloor. Such occurrences were in areas where migrating sand waves had been present or where bottom features existed but were deemed navigationally insignificant.The barge lanes paralleling the Houston Shipping Channel have a controlling depth of 12 feet. As such, the lanes were evaluated for shoals exceeding this depth limit. Some minor shoaling (1 to 2 feet) was found encroaching the outside edges in several reaches however, discussion with USACE Galveston established these discrepancies as tolerable and not befitting for a formal Danger to Navigation report. All electronic correspondence pertaining to this matter may be found in Appendix II of this descriptive report. Chartlets pertaining to the matter and shared with USACE are shown below. Barge Lane Shoaling Chartlet, Cover Sheetfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/BargeLane1.JPGChartlet Indexfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/BargeLane2.JPGChartlet 1file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/BargeLane3.JPGChartlet 2file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/BargeLane4.JPGChartlet 3file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/BargeLane5.JPGChartlet 4file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/BargeLane6.JPGNo bottom samples were required for this survey.Shoreline was not assigned in the Hydrographic Survey Project Instructions or Statement of Work.No prior survey comparisons exist for this survey.The 2017-2018 Eighth District Gulf Coast Local Notice to Mariners listed five (5) ATONS coincident to the H12392 survey area which had been damaged at the time of data acquisition. All ATONS were lighted channel markers and included numbers "51," 71," "73,"75," and "76." Marker Discrepancies for lighted channel markers "71," "75," and "76" remained uncorrected by the survey end date, 31JAN2018. These Aids had been temporarily replaced by lighted buoys. See LNM tabulation graphics, below. A feature redundancy discrepancy was discovered for the Lower Galveston Bay Inner Range Front Light invoking the 2017 Features Scan (v8) tool in Pydro QC Tools. The conflict involved duplication of a light associated to that ATON; the 2018 USCG Light List only included 2 lights atop the range light however, 3 lights were listed in the ENC . As a result, the discrepancy was reported to MCD through its Nautical Discrepancy Reporting System on 5JULY2018. Email correspondences pertaining to this matter can be found in the Project Correspondence folder and show that MCD is making necessary corrections to the cell.USCG Local Notice to Mariner, Damaged Nav Aids.file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Discrepancies_Federal%20Aids.PNGUSCG Local Notice to Mariner, Corrected Nav Aids.file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Corrected_Federal%20Aids.PNGNo overhead features exist for this survey.A pipeline located in the south, just outside of the sheet limits where H12392 junctioned to H12391 was charted however it was not seen in bathymetry or SSS imagery.Pipeline (highlighted yellow), southern end of H12392.file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/pipeline%20sub%20feature.JPGPlatforms exist for this survey, but were not investigated.H12392 Submerged Platform, not investigated.file:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/submerged%20platform.JPGTanker traffic near this 1 foot shoal generated dangerous wakes, preventing a safe approach and favorable survey conditions.DJNo ferry routes or terminals exist for this survey.Abnormal seafloor and/or Environmental Conditions were observed in this survey, but were not investigated. A fluid mud layer is know to exist just above a firm mud bottom owing to numerous bayous draining into Galveston Bay. Shipping traffic propulsion and shrimp trawling operations generated turbidity plumes from this fluid mud layer some of the time. Soundings/Imagery had to be reacquired on several occasions due to this factor. Likewise, shoaling from sedimentation is persistent in this waterway. USACE and Houston Pilots are cognizant of this shoaling and contract dredging operations are continuous throughout the bay on any given day. Note that no dredging operations were observed inside the sheet limits at any time during acquisition of H12392. No present or planned construction or dredging exist within the survey limits.Flier Finder v7 QC Check, 12 FliersFlier Finder v7 QC generates 12 fliers in the finalized 50cm base surface. Fliers had been inspected and corrected numerous times to no avail and are all the Number 3 "Adjacent Cells" class. Default filter values were used for this QC check. Output files for this check can be found in the DR's "Support _Files//QC_Reports" folder. See Image below.12 Fliers, Flier Finder v7 Settings and Resultsfile:///M:/OPRK414NRT417/Surveys/H12392/Office_Processing/Reports_office/Support_Files/Graphics/Flier_Finder_12.JPGNo 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 and Specifications Deliverables, Field Procedures Manual, 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.Dan JacobsChief of Party2019-01-31