OPR-K371-KR-16 Paul L. Donaldson Gulf of Mexico Leidos H12875 1 29 NM South Southeast of Sabine Pass Louisiana United States 40000 2016 Paul L. Donaldson Basic Hydrographic Survey 2016-05-12 2016-06-06 2016-10-01 Multibeam Echo Sounder Side Scan Sonar Multibeam Echo Sounder Backscatter meters UTC Atlantic Hydrographic Branch Contract: EA-133C-14-CQ-0033/T-0002. Contractor: Leidos, 221 Third Street, Newport, RI 02840 USA. Subcontractors: Divemasters, Inc., 15 Pumpshire Road, Toms River, NJ 08753; OARS, 8705 Shoal Creek Blvd, Suite 109, Austin, TX 78757. Leidos Doc 17-TR-002 All times were recorded in UTC. Data were collected in UTM Zone 15. Contractor The area surveyed was a section of the Gulf of Mexico south southeast of Sabine Pass, LA (Figure 1). 29.30396 093.63616 29.22970 093.45302 H12875 Survey Bounds file:///SupportFiles/H12875_Figure_1.jpg Survey limits were acquired in accordance with the requirements in the Project Instructions and the NOS Hydrographic Survey Specifications and Deliverables (HSSD). The purpose of this survey is to update existing NOS nautical charts. This project is located in a highly trafficked critical area south of the Louisiana coast as designated in the 2012 NOAA Hydrographic Survey Priorities. The entire survey is adequate to supersede previous data. Leidos warrants only that the survey data acquired by Leidos and delivered to NOAA under Contract EA-133C-14-CQ-0033 reflects the state of the sea floor in existence on the day and at the time the survey was conducted. H12875 was surveyed in accordance with the following documents: 1. Project Instructions, OPR-K371-KR-16, dated 12 May 2016 2. NOS Hydrographic Survey Specifications and Deliverables (HSSD), March 2016 3. OPR-K371-KR-16 Statement of Work, dated 12 May 2016 All waters in survey area. Either A) Complete MBES with backscatter, OR B) 100% SSS with concurrent set line spacing MBES with backscatter. Note: Complete MBES is sufficient for both determination of least depth identified with SSS and for disproving a feature – 100% SSS is insufficient to disprove a feature. Refer to Section 6.1.2 of the HSSD to confirm proper SSS acquisition parameters. Gaps in SSS coverage should be treated as gaps in MBES coverage and addressed accordingly. Leidos chose to achieve the coverage requirement using 100% side scan sonar with concurrent set line spacing multibeam echo-sounder with backscatter. Survey coverage was in accordance with the requirements in the Project Instructions and the HSSD. Final Bathymetry Coverage for H12875 file:///SupportFiles/H12875_Figure_2.jpg M/V Atlantic Surveyor 0 0 0 0 0 1007.75 0 57.68 0 0 0 0 0 0 1007.75 0 57.68 0 5.72 6 0 0 0 41.63 2016-06-06 2016-06-07 2016-06-08 2016-06-10 2016-06-11 2016-06-12 2016-06-13 2016-06-14 2016-06-17 2016-06-18 2016-07-29 2016-07-30 2016-09-27 2016-09-28 2016-10-01 Leidos used their ISS-2000 software on a Windows 7 platform to acquire these survey data. Survey planning and data analysis were conducted using the Leidos SABER software on Red Hat Enterprise 6 Linux platforms. L-3 Klein 3000 side scan data were collected on a Windows 7 platform using L-3 Klein’s SonarPro software. Subsequent processing and review of the side scan data, including the generation of coverage mosaics, were accomplished using SABER. A detailed description of the systems and vessel used to acquire and process these data is included in the Data Acquisition and Processing Report (DAPR) for OPR-K371-KR-16, delivered on 13 January 2017. There were no variations from the equipment configuration described in the DAPR. M/V Atlantic Surveyor 110 9 The M/V Atlantic Surveyor was used to collect multibeam sonar (RESON SeaBat 7125 SV), side scan sonar (L-3 Klein 3000), and sound speed data during twenty-four hours per day survey operations. A detailed description of the vessel used is included in Section A of the DAPR RESON SeaBat 7125 SV MBES L-3 Klein 3000 SSS Applanix POS/MV 320 V5 Positioning and Attitude System Trimble Probeacon Positioning System ODIM Brooke Ocean MVP-30 Sound Speed System A detailed description of the equipment installed is included in Section A of the DAPR. There were 57.68 linear nautical miles of crosslines and 1007.75 linear nautical miles of mainscheme lines surveyed on H12875. This resulted in crossline mileage of approximately 5.72% of the main scheme mileage which meets the requirement to achieve approximately four percent of main scheme mileage for a complete coverage multibeam survey (Section 5.2.4.3 of the HSSD). H12875 requirements were for complete coverage, Option B, based on the classifications defined in Section 5.2.2 of the HSSD; "100% side scan sonar coverage with concurrent multibeam bathymetry collection with complete coverage multibeam developments (i.e. 1m grid resolution in 0-20m depth range) of contacts and features.” The mainscheme lines were oriented 90°/270° and spaced 80 meters apart. Crosslines were oriented 0°/180° and spaced 1500 meters apart. Refer to the “Multibeam Processing Log” section within Separates I for information on the delineation of mainscheme and crossline data files. In the field, hydrographers conducted daily comparisons of mainscheme to near nadir crossline data to ensure that no systematic errors were introduced, and to identify potential problems with the survey systems. After the application of all correctors and completion of final processing in the office, separate one-meter grids were built. One grid contained the full valid swath (±60° from nadir, Class 2) of mainscheme multibeam and the other included only the near nadir swath (±5° from nadir, Class 1) crossline data. Difference grids were then generated by subtracting one grid from the other. The SABER Frequency Distribution Tool was used to analyze the difference grids. All comparisons fell within the requirement defined in Section 5.2.4.3 of the HSSD, which states that at least 95% of the depth difference values are to be within the maximum allowable total vertical uncertainty. Figure 3 summarizes the comparison results. See Separates II for a complete discussion of the analysis and tabular results. Summary of Crossing Analysis file:///SupportFiles/H12875_Figure_3.jpg The Total Propagated Uncertainty (TPU) model that Leidos has adopted had its genesis at the Naval Oceanographic Office (NAVOCEANO), and is based on the work by Rob Hare and others (“Error Budget Analysis for NAVOCEANO Hydrographic Survey Systems, Task 2 FY 01”, 2001, HSRC FY01 Task 2 Final Report). Once the TPU model is applied to the GSF bathymetry data, each beam is attributed with the horizontal uncertainty and the vertical uncertainty at the 95% confidence level. For specific details on the use and application of the SABER Total Propagated Uncertainty model, see Section B.1 in the DAPR. The vertical and horizontal uncertainty values that were estimated by the TPU model for individual multibeam soundings varied little across the dataset, tending to be most affected by beam angle. During application of horizontal and vertical uncertainties to the GSF files, individual beams where either the horizontal or vertical uncertainty exceeded the maximum allowable IHO S-44 5th Edition Order 1a specifications were flagged as invalid. As a result, all individual soundings used in development of the final CUBE depth surface had modeled vertical and horizontal uncertainty values at or below the allowable IHO S-44 5th Edition, Order 1a uncertainty. During the creation of the CUBE surface, two separate vertical uncertainty surfaces are calculated by the SABER software. One surface contains the standard deviation of all soundings that are contributing to the CUBE hypothesis (Hyp. StdDev), and the other contains the average of the vertical uncertainty of all soundings contributing to the CUBE hypothesis (Hyp. AvgTPE). A third vertical uncertainty surface is generated from the larger value of these two uncertainties at each node and is referred to as the Hypothesis Final Uncertainty. For specific details on this process see Section B.2 of the DAPR. The final one-meter PFM CUBE surface contained final vertical uncertainties that ranged from 0.470 to 1.340 meters. The IHO Order 1a maximum allowable vertical uncertainty was calculated to range between 0.512 to 0.545 meters, based on the minimum CUBE depth (8.643 meters) and maximum CUBE depth (16.719 meters). The SABER Check PFM Uncertainty function was used to highlight all instances in the Hypothesis Final Uncertainty surface where a given node exceeded the IHO Order 1a allowable vertical uncertainty for the CUBE depth at that node. The final one-meter PFM CUBE surface contained 277 individual CUBE nodes with final vertical uncertainties that exceeded IHO Order 1a allowable vertical uncertainty. The nodes that exceed the IHO Order 1a allowable vertical uncertainty for the CUBE depth were primarily located around features or steep slopes of jack-up rig depressions where there was a high variability in the depth soundings. There were two nodes where the uncertainty was high resulting from sparse outer edge data between overlap of a holiday line. There were four nodes where uncertainty was high resulting from sparse outer edge data between overlap of mainscheme and crossline data. The SABER Frequency Distribution Tool was used to review the Hypothesis Final Uncertainty surface within the final one-meter PFM grid. The results show that in the final one-meter PFM grid, 99.99% of all nodes had final uncertainties less than or equal to 0.500 meters. An analysis of H12875 junctions with contemporary surveys was performed. Figure 4 shows the general locality of H12875 as it relates to the contemporary sheets for which junction analysis was performed. Table 6 provides details for each contemporary sheet junction analysis performed. See Separates II for a complete discussion of the junction results and tabular listings. At the time of this delivery, Leidos had not completed processing of H12876 and H12877. Therefore, no final junction analysis with H12876 and H12877 was conducted. General Locality of H12875 with Contemporary Surveys file:///SupportFiles/H12875_Figure_4.jpg H10948 20000 2000 Fugro GeoServices, Inc. W H12875 junctions with H10948 to the west; 95.25% of the comparisons agreed within ±0.45 meters. H12730 40000 2015 Leidos, Inc. N H12875 junctions with H12730 to the north; 95.38% of the comparisons agreed within ±0.29 meters. H12731 40000 2016 Leidos, Inc. NE H12875 junctions with H12731 to the northeast; 97.22% of the comparisons agreed within ±0.14 meters. H12838 40000 2016 Leidos, Inc. E H12875 junctions with H12838 to the east; 95.31% of the comparisons agreed within ±0.22 meters. Sonar system quality control checks were conducted as detailed in Section A.5, Multibeam Systems and Operations, of the DAPR. There were no conditions or deficiencies that affected equipment operational effectiveness. Localized weather events produced a difference in water levels between the survey area and the water level gauge. The artifact was seen in the multibeam CUBE surface and generally ranged between 20 to 30 centimeters when present (Figure 5). Additionally, positional scatter resulting from normal DGPS variability was sometimes visible in the sounding data for discrete features with multiple passes. Figure 6 represents small positional differences of 1.5 meters over an exposed pipeline from two separate passes. This horizontal offset was not always present as depicted in Figure 7, which shows five passes over a distinct object (represented by five colors) which align quite well (within 0.5 meters). These occasional vertical and horizontal offsets observed within H12875 were within the IHO Order 1a allowable vertical and horizontal uncertainty for these water depths. CUBE Depth Artifact Resulting From Local Weather Events file:///SupportFiles/H12875_Figure_5.jpg DGPS Positional Variation Between Passes file:///SupportFiles/H12875_Figure_6.jpg No DGPS Positional Variation Between Multiple Passes and Multiple Headings file:///SupportFiles/H12875_Figure_7.jpg On the M/V Atlantic Surveyor, the MVP-30 was used to collect sound speed profile (SSP) data. SSP data were obtained at intervals frequent enough to meet depth accuracy requirements. Section 5.2.3.3 of the HSSD requires that if the sound speed measured at the sonar head differs by more than two meters/second from the commensurate profile data, then another cast shall be acquired. There were times when the sound speed values exceeded the two meters/second threshold due to the local temporal and tidal variability. During these times, several profiles were acquired and reapplied in an effort to reduce these effects. The product of this effort resulted in the final data bearing no significant artifacts due to sound speed differences. All sound speed profiles applied for online bathymetry data collection were acquired within the bounds of the survey area. Please refer to the DAPR for specific details regarding acquisition (Section A.7) and application (Section C.1.3) of sound speed profiles. Confidence checks of the sound speed profile casts were conducted by comparing at least two consecutive casts taken with different SVP Smart Sensors. Seven sound speed confidence checks were conducted during H12875 and the results can be found in Separates II within the “Comparison Cast Log” section. All individual sound speed profile files are delivered with the H12875 data and are broken out into sub-folders, which correspond to the purpose of each cast. Also, all individual sound speed profiles for H12875 have been concatenated into four separate files based on the purpose of the cast, provided in CARIS format files (.svp), and delivered under (H12875/Data/Processed/SVP/CARIS_SSP) on the delivery drive. Refer to Separates II for more details. All equipment and survey methods are detailed in the DAPR. Leidos chose to achieve the coverage requirement using 100% side scan sonar with concurrent set line spacing multibeam echo-sounder with backscatter. To achieve this coverage, the M/V Atlantic Surveyor used a towed L-3 Klein 3000 side scan sonar set to a 50-meter range scale. Mainscheme line spacing was 80 meters, which ensured 100% side scan coverage. Both the Project Instructions and the HSSD stated that 100% side scan was insufficient to disprove a charted feature. Therefore, Leidos reviewed the Composite Source File (CSF), BSB charts, and ENC charts and completed an additional 100% side scan coverage, and resulting multibeam coverage over common charted objects not found during survey in order to verify disproval. A radius was determined from the Project Instructions, which stated, “In the case of the unassigned offshore oil platforms within the survey area, should the field unit observe that the feature is not visible, then a formal disproval is required. For the purposes of disproval, charted features labeled with a “PA” will have a search radius of 160 meters, a “PD” will have a search radius of 240 meters, and all other features without a position qualifier will have a search radius of 80 meters.” For the wellheads assigned in the final CSF file, coverage requirements for disproval were provided via email from NOAA on 16 June 2016 stating “If the obstruction is not found, in cases where 100% SSS with concurrent multibeam is being used as the primary coverage technique, a 50m disproval search radius using a technique described in Section 7.3.4 is necessary.” The SABER Gapchecker routine was used to flag multibeam data gaps within the CUBE surface. Additionally, the entire surface was visually scanned for holidays at various points during the data processing effort. Additional survey lines were run to fill any holidays that were detected. A final review of the CUBE Depth surface of the one-meter PFM containing all multibeam data showed that there were a few instances where a three by three node gap exists. These gaps resulted from the holiday line data being slightly offset from the original line due to vessel line following. All grids were examined for the number of soundings contributing to the chosen CUBE hypotheses for each node by running SABER’s Frequency Distribution Tool on the Hypothesis Number of Soundings (Hyp # Soundings) surface for the one-meter PFM. The Hyp # Soundings surface reports the number of soundings that were used to compute the chosen hypothesis. Analysis of the H12875 final one-meter PFM grid revealed that 98.66% of all nodes contained five or more soundings; satisfying the requirements for complete coverage surveys, option B, as specified in Section 5.2.2.3 of the HSSD. All data reduction procedures conform to those detailed in the DAPR. All sounding systems were calibrated as detailed in the DAPR. 2017-01-13 In accordance with the HSSD and Project Instructions, Leidos collected multibeam backscatter with all GSF data acquired by the RESON Seabat 7125 SV. The multibeam settings used were checked to ensure acceptable quality standards were met and to avoid any acoustic saturation of the backscatter data. The multibeam backscatter data acquired were written to the GSF in real-time by ISS-2000 and are delivered in the final GSF files for this sheet. Backscatter was not processed by Leidos. Leidos SABER 5.2.0.19.02 Leidos SABER 5.2.0.19.02 NOAA Extended Attribute File V5-4. The primary data processing software used for both bathymetry and imagery was SABER. There were no software configuration changes after the DAPR was submitted. H12875_MB_1m_MLLW_Final_1of2 BAG 1 8.643 16.719 N/A Concurrent set line spacing MBES H12875_MB_1m_MLLW_Final_2of2 BAG 1 11.171 16.500 N/A Concurrent set line spacing MBES H12875_SSS_1m_100 SSS Mosaic (.tif;.tfw) 1 0 0 N/A 100% SSS H12875_SSS_Disproval SSS Mosaic (.tif;.tfw) 1 0 0 N/A 200% SSS Charted Object Disproval A PFM CUBE Depth surface was used to assess and document multibeam survey coverage. The CUBE depth is populated with either the node’s chosen hypothesis or the depth of a feature or designated sounding (Section D.2.11) set by the hydrographer, which overrides the chosen hypothesis. The range of CUBE depths in H12875 was from 8.643 meters (28.356 feet, 0.470-meter uncertainty) to 16.719 meters (54.852 feet, 0.480-meter uncertainty). Section 5.2.2.3 of the HSSD requires a one-meter grid resolution for depths ranging from zero meters to 20 meters for Complete Coverage. The final gridded bathymetry data are delivered as Bathymetric Attributed Grids (BAG). The BAG files were exported from the CUBE PFM grid as detailed in Section B.2.5 of the DAPR. For all details regarding side scan data processing, see Section B.3 of the DAPR. Leidos chose to adhere to the coverage requirements in the Project Instructions with 100% side scan coverage with concurrent set line spacing MBES with backscatter. Both the Project Instructions and the HSSD stated that 100% side scan was insufficient to disprove a charted feature. Therefore, 100% side scan coverage was collected and verified for the entire survey area, and an additional 100% coverage was collected over charted objects that were not found to verify disproval. Leidos generated two separate coverage mosaics at one-meter cell size resolution as specified in Section 8.2.1 of the HSSD. The first 100% and second 100% disproval coverage mosaics were independently reviewed using tools in SABER to verify data quality and swath coverage. Both coverage mosaics are determined to be complete and sufficient to meet the requirements contained within the Project Instructions. The mosaics are delivered as TIFF (.tif) images with accompanying world files (.tfw), refer to Table 7. Side scan sonar contacts were investigated and confirmed using SABER Contact Review. All side scan sonar contacts and accompanying images are delivered in the Side Scan Sonar Contacts S-57 file; for specifics refer to Section D.2.13. No vertical or horizontal controls were established, recovered, or occupied during data acquisition for OPR-K371-KR-16, which includes H12875. Therefore, a Horizontal and Vertical Control Report was not required. Mean Lower Low Water Calcasieu Pass, LA 8768094 Discrete Zoning 8768094_verified_01June16_to_04Oct16.tid Verified Observed K371KR2016CORP.zdf Final 1957-08-13 1957-08-15 No final tide note was provided by the NOAA Center for Operational Oceanographic Products and Services (CO-OPS). Leidos is not required to have a final tide note from CO-OPS for H12875 however, a final tide note has been provided by Leidos in Appendix I. The Tides Statement of Work specified NOAA tide station 8768094 Calcasieu Pass, LA as the source for water level correctors for OPR-K371-KR-16. A full explanation of the tide zone assessment is detailed in Section C.4 of the DAPR. For H12875, 8768094 Calcasieu Pass, LA was the source of all final verified water level heights for determining correctors to soundings. All data for H12875 were contained within two tide zones (WGM400, and WGM407) which were provided from NOAA. Leidos did not revise the delivered tide zones for tide station 8768094 Calcasieu Pass, LA as the water level zoning parameters in the file K371KR2016CORP.zdf, provided by National Ocean Service (NOS) were deemed adequate for the application of observed verified water levels. As a result, they were accepted as final and applied to all H12875 bathymetry data. ERS via Constant Separation Model North American Datum of 1983 (NAD83) UTM Zone 15, North Single Base English Turn, LA (293 kHz) Angleton, TX (301 kHz) Aransas Pass, TX (304 kHz) Please refer to the DAPR for details regarding all antenna and transducer offsets. During survey data acquisition, the ISS-2000 real-time system provided a continuous view of the positioning comparison between the POS/MV and the Trimble DGPS. An alarm was triggered within ISS-2000 if the comparisons were not within an acceptable range. Any soundings with total horizontal uncertainties exceeding the maximum allowable IHO S-44 5th Edition Order 1a specifications were flagged as invalid and therefore were not used in the CUBE Depth calculations. The chart comparisons were conducted using the Leidos SABER software to view the BSB raster charts with overlain data for H12875 such as the CUBE surface, selected soundings, contacts, and features. Charting recommendations for depths follow Section 5.1.2 of the HSSD where depths and uncertainties are to be rounded by standard arithmetic rounding (round half up). For ENC comparisons, a combination of CARIS’ EasyView and SABER were used. United States Coast Guard (USCG) District 8 Local Notice to Mariners publications were reviewed for changes subsequent to the date of the Project Instructions and before the end of survey (as specified in Section 8.1.4 of the HSSD). The Notice to Mariners reviewed were from 22/16 (01 June 2016) until week 40/16 (05 October 2016). Two Danger to Navigation Reports (DTONs) were submitted during survey operations and were reported in the 0826g2016 Local Notice to Mariners. Specific details pertaining to the two DTONs are provided in the H12875 S-57 Final Feature File (FFF), named H12875.FFF.000. H12875 data meet data accuracy standards and bottom coverage requirements. Recommend updating the common areas of all charts using data from this survey. Charting recommendations for all features found, and updates to charted features, are documented in the H12875 S-57 FFF. Additional charted objects such as submarine pipelines and platforms are discussed in later sections. 1116 49 458596 79 2016-02 2016-11-22 2016-10-29 Chart 1116A covers the H12875 survey area in its entirety. CUBE depths within sheet H12875 agreed with the charted depths across most of the survey area, or were generally 0.5 fathoms deeper than the charted depths. 11330 195 250000 22 2013-04 2016-11-22 2016-10-29 Chart 11330 covers the H12875 survey area in its entirety. CUBE depths within sheet H12875 agreed with the charted depths across most of the survey area, or were generally within ±3 feet of the charted depths. 11332 125 80000 33 2013-01 2016-11-22 2016-10-29 Chart 11332 covers the H12875 survey area west of 093° 33’ 53.71”W. CUBE depths within sheet H12875 agreed with the charted depths across most of the survey area, or were generally within ±2 feet of the charted depths. 11340 49 458596 79 2016-02 2016-11-22 2016-10-29 Chart 11340 covers the H12875 survey area in its entirety. CUBE depths within sheet H12875 agreed with the charted depths across most of the survey area, or were generally 0.5 fathoms deeper than the charted depths. 11341 124 80000 44 2013-03 2016-11-22 2016-10-29 Chart 11341 covers the H12875 survey area north of 029° 14’ 54.66”N. CUBE depths within sheet H12875 agreed with the charted depths across most of the survey area and were generally within ±1 foot of the charted depths. US3GC02M 250000 27 2016-10-31 false 2014-10-27 ENC US3GC02M covers the H12875 survey area in its entirety. CUBE depths within sheet H12875 agreed with the charted depths across most of the survey area and were generally within ±1.00 meters of the charted depths. US4LA10M 80000 10 2016-11-18 false 2014-11-03 ENC US4LA10M covers the H12875 survey area, east of 093° 34’ 00.63”W and north of 29° 15’ 02.00”N. CUBE depths within sheet H12875 agreed with the charted depths across most of the survey area and were generally within ±0.50 meters of the charted depths. US4TX71M 80000 29 2016-10-28 false 2016-10-28 ENC US4TX71M covers the H12875 survey area, west of 093° 34’ 00.63”W. CUBE depths within sheet H12875 agreed with the charted depths across most of the survey area and were generally within ±0.50 meters of the charted depths. No Maritime Boundary Points were assigned for this survey. A charted obstruction PA, charted Ruins PA and charted well fell within the H12875 survey bounds but were not found during survey. See the H12875 S-57 FFF for details and recommendations regarding these charted features. A wreck and obstruction were charted within the survey area as a result of DTONs submitted for H12875 during survey operations (Section D.1.6). The details resulting from final processing of the data, and recommendations, are captured in the H12875 S-57 FFF. See the H12875 S-57 FFF for all the details and recommendations regarding new uncharted features. 2 2016-06-17 2016-06-17 There were two Danger to Navigation Reports (DTONs) submitted for H12875 by Leidos in S-57 format to the Atlantic Hydrographic Branch (AHB). AHB submitted DTON_01 and DTON_02 to the Nautical Data Branch (NDB)/Marine Chart Division (MCD) as a single submission on 17 June 2016 (H12875_DtoN_1-2.zip). A copy of the AHB verification email and AHB DTON report, in PDF format, submitted to the Nautical Data Branch (NDB)/Marine Chart Division (MCD) for DTON_1-2 are included in a sub-directory within Appendix II of this Data Report. Figure 8 provides a list of DTONs and their associated Feature number and object class in the H12875 S-57 FFF. Per guidance from AHB (via email correspondence 20 January 2016), exposed pipelines should not to be submitted as DTONs but as Feature Reports, in S-57 format. Leidos submitted one Feature Report in S-57 format to AHB on 21 December 2016, which AHB forwarded to the Office of Coast Surveys Navigation Manager. Feature Report 1 contained six sections of exposed pipeline of various lengths. Figure 9 provides a list of Feature Reports and their associated Feature number and object class in the H12875 S-57 FFF. DTON Feature Numbers file:///SupportFiles/H12875_Figure_8.jpg Feature Report Submitted to AHB file:///SupportFiles/H12875_Figure_9.jpg There were no significant shoals or hazardous features within the survey area covered by H12875. There were no channels within the survey area covered by H12875. In accordance with both the Project Instructions and Section 7.2.2 of the HSSD, bottom characteristics were obtained for H12875. Bottom characteristics were acquired at six locations, five of which were assigned in the Project Reference File (PRF) by NOAA. Leidos did not modify any bottom sample locations from the locations proposed by NOAA in the PRF. A sixth bottom sample was collected after review of the side scan data indicated a change in reflectivity which was approximately 2.5 kilometers from the closest assigned bottom sample location. Bottom characteristics collected during H12875 are included in the H12875 S-57 FFF within the Seabed Area (SBDARE) object and classified according to the requirements set forth in Appendix H of the HSSD. All features within the Composite Source File (CSF) were resolved. There were no assigned features inshore of the NALL. Junction analysis with prior surveys H10948, H12730, H12731, and H12838 (collected in 2000, 2015, 2016, and 2016, respectfully) were conducted, and the results are presented in Section B.2.4 of this Data Report and within Separates II. There were no aids to navigation that fell within the survey area of H12875. There were no overhead features within the H12875 survey area. Eight pipeline (PIPSOL) objects are delivered in the H12875 S-57 FFF to represent sections of pipeline found, utilizing multibeam and side scan data, within the bounds of H12875. Six pipeline objects are delivered as point objects identified as exposed pipelines within multibeam data, while two pipeline objects are line objects depicting pipelines observed in the side scan data only. See Section D.1.6 for additional information. Additional charted pipelines fall within the survey coverage; however, the multibeam and side scan data do not show evidence of them. No ferry routes or terminals exist within the H12875 survey area. There were no assigned offshore platform objects in the OPR-K371-KR-16_CSF_Version2.000, provided on 16 June 2016, which fell within the H12875 survey area. However, at the start of survey, there were two charted platforms within the H12875 SOW area associated with assigned obstructions (wellhead) within the OPR-K371-KR-16_CSF_Version2.000 file. One charted platform was found within the bounds of H12875 during survey operations on 07 June 2016 (JD159), with an identification placard embossed with WC294-A OCS-G-4090. Subsequently during item investigations on 28 September 2016 (JD 272), the platform was no longer present. An area with a radius of at least 80 meters was covered by 200% side scan and resulting multibeam. There was no evidence of the platforms existence in the side scan or multibeam data and no platforms were visible above the waterline. In addition, a separate charted platform was not found during survey operations. An area with a radius of at least 80 meters was covered by 200% side scan and resulting multibeam. There was no evidence of the platforms existence in the side scan or multibeam data and no platforms were visible above the waterline. This platform is no longer charted in the latest edition charts. See the H12875 S-57 FFF Offshore Platform (OFSPLF) objects, for details and charting recommendations on the platform currently charted. During data acquisition on H12875 there were intermittent local weather events producing increased winds and sea state, (see section B.2.7). Occasionally during the localized weather events, the water levels within the survey area differed slightly (20 to 30 centimeters) from the provided tide zone time and range ratios compared to the gauge at Calcasieu Pass, LA. However, the vertical offsets observed were within the IHO Order 1a allowable vertical and horizontal uncertainty for the H12875 water depths. No abnormal seafloor or environmental conditions, as defined in Section 8.1.4 of the HSSD, exist within the H12875 survey area. No construction or dredging exists for the H12875 survey. No new survey recommendations are made for the area surrounding the H12875 survey area. Designated soundings were used to help better preserve the shallowest sounding relative to the computed depth surface. Separate flags exist in the Generic Sensor Format (version 3.06) for designated soundings and features. All depths flagged as features and designated soundings override the CUBE best estimate of the depth in the final BAG files. Both the designated sounding and feature flags, as defined within GSF, are mapped to the same HDCS flag when ingested into CARIS (PD_DEPTH_DESIGNATED_MASK). No GSF designated sounding flags were set for H12875. Only significant features were set within H12875 and all information is contained in the H12875 S-57 FFF. Included with H12875 delivery is the S-57 FFF, H12875.FFF.000. Details on how this file was generated and quality controlled can be found in Section B.2.6 of the DAPR. The S-57 FFF delivered for H12875 contains millimeter precision for the value of sounding (VALSOU) attribute. As specified in Section 8.2 of the HSSD, the S-57 FFF is in the WGS84 datum and is unprojected with all depth units in meters. All significant, and recommended for charting, features found in H12875 are included within the S-57 FFF. In accordance with the HSSD, Leidos addressed all assigned objects within the bounds of H12875 from the provided CSF S-57 file in the S-57 FFF. For each feature contained in the FFF (S-57), the Feature Correlator Sheet was exported as an image file (.jpg) and is included in the S-57 FFF under the NOAA Extended Attribute field “images”. Included with the H12875 delivery is the Side Scan Sonar Contact S-57 File, H12875.SSCon.000. Details on how this file was generated and quality controlled can be found in Section B.3.5 of the DAPR. As specified in Section 8.2 of the HSSD, the S-57 feature file is in the WGS84 datum and is unprojected with all depth units in meters. All side scan contacts are retained within the Side Scan Sonar Contact S-57 File. For each contact included in this S-57 file, a JPEG image of the side scan contact is included under the NOAA Extended Attribute field “images”. A Coast Pilot Review Report for OPR-K371-KR-16 was not required per guidance from the NOAA COR (see 06 June 2016 email in Appendices II Supplemental Survey Records and Correspondence). The Coast Pilot was reviewed for the port of call and areas frequently transited, and no changes are recommended. On 16 June 2016, NOAA delivered OPR-K371-KR-16_CSF_Version2.000 which contained thirteen wellhead features within the H12875 survey bounds requiring investigation (See Appendix II). No wellheads were found at the thirteen locations surveyed as part of H12875. All wellhead locations were covered in accordance with Section 7.3.4 of the HSSD with a minimum of 200% side scan data and resulting multibeam data. A minimum of 50-meter disproval search radius was covered as specified in the correspondence dated 16 June 2016. No inset recommendations are made for the area covered by the H12875 survey. 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 BAG files, 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, Project Instructions, and the OPR-K371-KR-16 Statement of Work. 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. Paul L. Donaldson Chief Hydrographer 2017-01-13 OPR-K371-KR-16_DAPR.pdf 2017-01-13