S/V Blake41.40.00.00.00.025.27.80.0547.941.40.00.00.00.025.24.57.80.0547.92016-09-072016-09-082016-09-092016-09-102016-09-112016-09-182016-09-192016-11-165038.3900The entire survey is adequate to supersede previous data.The purpose of this project is to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products. This project includes two survey areas totaling 263 SNM of which 226 SNM are classified as emerging critical areas, 32 SNM as priority two areas and 2 SNM as priority three as identified in the 2012 NOAA Hydrographic Survey Priorities. The first area is a narrow corridor located to the west of the Chandeleur Islands and extends from Baptiste Collette, LA towards Gulfport, MS. This corridor will serve as an alternate traffic route during the August 2016 closure of the INHC Lock in New Orleans. The second area, located to the east of the Chandeleur Islands, is a heavily trafficked area and encompasses approximately 125 SNM with multiple oil platforms and well heads. All Sheet NumbersAll MBES acquisition requires backscatter acquisition (refer to HSSD Section 6.2)Sheet Number 3 - 10Complete Coverage (refer to HSSD Section 5.2.2.3)Complete coverage was obtained over the survey area using 100% side scan sonar coverage with concurrent multibeam echosounder (MBES) and backscatter. This coverage type follows Option B of the Complete Coverage requirement specified in Section 5.2.2.3 of the 2016 HSSD. Significant side scan sonar contacts were developed with multibeam sonar at complete coverage resolution as required by the coverage classification. Complete coverage multibeam was obtained within the search radii (160 meters for charted features labeled with PA and 80 meters for charted features without a PA label) for all feature disapprovals. Survey coverage was obtained within the survey area depicted in the Project Reference File (PRF) OPR-J311-KR-16_PRF.000.Survey Limits were surveyed in accordance with the requirements in the Project Instructions and the HSSD. OPR-J311-KR-16 Assigned Survey AreasSupportFiles\OPR-J311-KR-16_AssignedSurveyAreas.pngDavid Evans and Associates, Inc. (DEA) conducted a hydrographic survey of the assigned area in the Gulf of Mexico, east of the Chandeleur Islands. Survey H12954 was conducted in accordance with the Statement of Work (July 15, 2016) and Hydrographic Survey Project Instructions (July 15, 2016). The Hydrographic Survey Project Instructions reference the National Ocean Service (NOS) Hydrographic Surveys Specifications and Deliverables Manual (HSSD), 2016 as the technical requirements for this project.29.775869611188.706727611129.981859694488.7903403056H12954 Survey OutlineSupportFiles\H12954_SurveyOutline.png Southeastern Vicinity of the Chandeleur IslandsDavid Evans and Associates, Inc.OPR-J311-KR-16Eastern Vicinity of the Chandeleur IslandsContractormetersNAD83, UTM Zone 16 North, Meters, Times are UTC. The purpose of this contract is to provide NOAA with modern, accurate hydrographic survey data with which to update nautical charts of the assigned area.Reson 7125 SV2EdgeTech 4200-HFUniversal Transverse Mercator (UTM)Jonathan L. Dasler, PE, PLS, CH2016-07-152016-09-072016-11-16Basic Hydrographic Survey2016Atlantic Hydrographic BranchUTC5 NM E of Chandeleur IslandsUnited States40000Mississippi9H12954A complete description of the horizontal and vertical control for survey H12954 can be found in the OPR-J311-KR-16 Horizontal and Vertical Control Report (HVCR), which is expected to be submitted with the deliverables of last survey in the OPR-J311-KR-16 project area. A summary of horizontal and vertical control for this survey follows. The horizontal datum for the project was the North American Datum of 1983 (NAD 83) as specified by Hydrographic Technical Directive (HTD) 2016-3: Revision of Horizontal Datum in 2016 HSSD. A copy of this HTD is included in the OPR-J311-KR-16 Project Correspondence. Verified Observed8735180.tidFinalJ311KR2016RevCORP.zdfTide zoning file J311KR2016RevCORP.zdf was provided with the project instructions and used for sounding correction within the assigned survey area.8735180Dauphin IslandMean Lower Low WaterEnglish Turn, LA (293 kHz)NAD83 UTM Zone 16 NorthNorth American Datum of 1983 (NAD83)No shoal or hazardous features were charted or located within the H12954 survey area. Coastal chart 11373 was compared to US4LA34M within the H12954 survey area. The soundings charted on the RNC do not match those on the ENC. It appears that soundings from hydrographic project OPR-J348-KR-13, which were added to RNC 11373 as part of the release of Edition 52 (5/4/2015), were never applied to ENC US4LA34M. Soundings included in the ENC are attributed with Source Indication (SORIND): US,US,graph,Chart 11363 and Source Date (SORDAT): 20030900. These soundings agree with previous editions of the RNC 11373. Hydrographic project OPR-J348-KR-13, which was performed in 2013, included surveys H12528, H12529, and H12530. The hydrographer recommends updating US4LA34M with soundings from surveys H12528, H12529, and H12530.2016-12-31112017-01-172015-058000011373Coastal chart 11363 was compared to US4LA34M within the H12954 survey area. As with the 11373 comparison, soundings charted on RNC 11363 and ENC US4LA34M disagree within the footprint of hydrographic project OPR-J348-KR-13. It appears that ENC US4LA34M has not been updated with soundings acquired during this project. The hydrographer recommends updating US4LA34M with the most recent contemporary surveys. A discrepancy was also observed in the charting of H12954 Danger to Navigation (DtoN) 01. The danger was charted on the ENC as an obstruction while it was charted on the RNC as a sounding. 2017-01-144512017-01-242017-018000011363Inadequate depiction of pipelines on Chart 11366 SupportFiles\H12954_Pipelines.pngAs with the larger scale charts, DtoN 01 was charted on the ENC as an obstruction while it is charted on the RNC as a sounding. Additionally, pipelines charted on 11366 and US3GC04 terminate at the junction with large scale chart coverage from 11363 and US4LA34M. As seen in Figure 10, numerous pipelines, both inside and outside of the H12954 survey area, are not accurately depicted on the smaller scale charts. The hydrographer recommends a review of this discrepancy by the Marine Chart Division (MCD).2017-01-141612017-01-242015-0625000011366Depth Difference between H12954 and chart US4LA34MSupportFiles\H12954_ChartComp_US4LA34M.pngIn general, surveyed depths range from two feet shoaler to five feet deeper than charted on ENC US4LA34M. Some depths, mostly in southern portion of the survey area, are as much as seven feet deeper than charted.false29US4LA34M2015-01-062017-01-3180000Depth Difference between H12954 and chart US3GC04MSupportFiles\H12954_ChartComp_US3GC04M.pngIn general, surveyed depths range from three feet shoaler to ten feet deeper than charted on ENC US3GC04M. false52US3GC04M2014-11-052016-12-14250000The H12954 survey area does not contain any anchorage areas, maintained navigation channels, or channel lines.The majority of the chart comparison was performed by comparing H12954 depths to a digital surface generated from electronic navigational charts (ENCs) covering the survey area. A 50-meter product surface was generated from a triangular irregular network (TIN) created from the soundings, depth contours, and depth features for each ENC scale. An additional 50-meter HIPS product surface of the entire survey area was generated from the finalized MBES CUBE surfaces. The chart comparison was conducted by creating and reviewing the resultant difference surface. The chart comparison also included a review of all assigned charted features within the survey area. The raster navigational chart (RNC) comparison was performed by manually comparing the RNC covering the survey area to the corresponding ENC and identifying discrepancies between the two chart formats. The electronic and raster versions of the relevant charts used during the comparison were reviewed to check that all US Coast Guard (USCG) Local Notice to Mariners (LNMs) issued during survey acquisition and impacting the survey area were applied and addressed by this survey.H12954 Danger to Navigation 012016-09-09H12954 Danger to Navigation 02 - Exposed Pipelines2016-11-14Two DtoNs were submitted for this survey. H12954 DtoN 01 reported an uncharted obstruction within the survey area. The processing branch revised the submittal, changing the feature type from obstruction to sounding, before forwarding the charting recommendation to the Nautical Data Branch. The DtoN, which has been added to the charts using preliminary survey information, is currently charted on the RNCs as a sounding and on the ENCs as an obstruction. H12954 DtoN 02 reported sections of pipeline which are visibly exposed on the seabed in the multibeam and side scan data. While not a direct hazard to surface navigation, these exposed pipelines were submitted using the DtoN process in order to facilitate the review and reporting of the exposed pipelines. 2Five bottom samples were acquired on September 18, 2016 (DN262). The sampling plan followed suggested sample locations included in the PRF provided by the Hydrographic Surveys Division.No Maritime Boundary Points were assigned for this survey.The survey area does not contain any charted features labeled as Position Approximate (PA), Reported, Position Doubtful (PD), or Existence Doubtful (ED). All uncharted features are portrayed in the FFF as surveyed and attributed with the description of ‘New’. Other than the previously mentioned junction analyses, no other comparisons with prior surveys were conducted.No new insets are recommended for this area.No Aids to Navigation (AtoNs) were charted within the H12954 survey area.There were no ferry routes or terminals within the survey area.Multiple pipelines are charted within the survey area and are visible in the survey data and bathymetric surfaces. In some areas, pipelines are exposed on the seabed or there is evidence of buried pipelines beneath the seabed. Sections of pipeline which are visibly exposed on the seabed were reported as a DtoN and are included in the H12954 FFF as pipeline features. These features were submitted to the processing branch using the DtoN process so that the proper authorities could be notified about the condition of the pipelines. No submarine cables or tunnels were charted or located within the H12954 survey area. No construction or dredging activities were observed during survey operations.There was no other information of scientific or practical value observed during the survey. Two platforms are charted within the survey area. Both of the charted platforms were disproved by the survey and are included in the FFF with description of ‘Delete’Shoreline investigation was not assigned for this survey.No new surveys or further investigations are recommended for this area.There were no overhead bridges, cables, or other structures which would impact overhead clearance in the survey area.Reson7125 SV2MBESEdgetech4200-HFSSSApplanixPOS/MV 320 v5Positioning & AttitudeRolls RoyceMVP30-350 with AML MVP XPrimary Sound Speed ProfilerAMLMicro SV Xchange Surface Sound SpeedSea-Bird Electronics SEACAT SBE 19-03 CTD Secondary Sound Speed ProfilerS/V Blake4.583S/V BlakeSupportFiles\Blake.pngThe OPR-J311-KR-16 Data Acquisition and Processing Report (DAPR), previously submitted with survey H12920, 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.2016-11-18End of project calibration test.MBES (400kHz)The H12954 survey was still active at time of DAPR submission. An additional calibration test which was not reported in the DAPR is included in Table 9. A revision to DAPR Appendix II, which includes this calibration test and results from a new weekly bar check, has been included with the H12954 deliverables.Data reduction procedures for survey H12954 are detailed in the DAPR. A summary multibeam processing log is included in Separate I of this report.6.004.0006 and 6.004.0009Chesapeake Technology, Inc.SonarWiz9.1.6CARISHIPSA detailed listing of all data processing software is included in the OPR-J311-KR-16 DAPR.5.3.4. Bathymetric grids were created relative to Mean Lower Low Water (MLLW) in CUBE format using Complete Coverage resolution requirements as described in the HSSD.CUBEH12954_MB_1m_MLLW Complete Coverage10.0017.901NOAA_1mCUBEH12954_MB_1m_MLLW_FinalFinalized Complete Coverage10.0017.901NOAA_1mMosaicH12954_SSS_1m_100100- percent coverage001N/AQuality control is discussed in detail in Section B of the DAPR. Results from weekly position checks and weekly 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.Additional discussion of these parameters is included in the DAPR. 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 where the standard deviation of the node was greater than the total propagated uncertainty. The resulting calculated uncertainty values of all nodes in the finalized 1-meter Complete Coverage multibeam surface range from 0.24 meters to 0.80 meters with a standard deviation of 0.013 meters. To determine if surface grid nodes met International Hydrographic Organization (IHO) Order 1 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 uncertainty value at each node. Values greater than 100% indicate nodes exceeding the allowable IHO uncertainty. For the 1-meter Complete Coverage multibeam surface, the allowable uncertainty utilized ranges from 43% to 149%. The mean allowable uncertainty for the surface is 46% with a standard deviation of 0.023. Nodes that were reported out of specification were coincident with areas of high depth standard deviation with steep slopes or high relief. All uncertainty values were within allowable specification prior to surface finalization when standard deviation was incorporated into the solution when it was greater than the node uncertainty.S/V Blaken/a1.00.5Discrete0.000.112H12954 Crossline DifferencesSupportFiles\H12954_XL_MS.pngCrosslines were run across the entire survey area in order 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 1-meter CUBE surface encompassing mainscheme, fill, and investigation data for the entire survey area. The QC Report tabular output and plot are included in Separate II. The results of the analysis meet the requirements as stated in the 2016 HSSD. Additional crossline analysis was performed by computing a 1-meter CUBE surface from the crossline data. The surface was then differenced from a 1-meter surface comprised of all mainscheme, fill, and investigation data. The resultant difference surface was exported using the Base Surface to ASCII function and statistics were compiled on the ASCII data. Results from the crossline to mainscheme difference analysis are depicted in Figure 4. The primary contributors to the largest differences (20 to 32 centimeters) are discrete tide zoning, sound speed artifacts, and minor horizontal offsets in the vicinity of a steep slope. Horizontal offsets are well within HSSD requirements and the expected accuracy of the DGPS positioning system.Approximately 15-minute intervals.A Rolls Royce Moving Vessel Profiler (MVP) was the primary instrument used to acquire sound speed readings during multibeam operations. MVP sound speed readings were measured at approximately 15-minute intervals during survey operations. Additional discussion of sound speed methods can be found in the DAPR. Survey H12954 junctions with surveys H12528, H12529, H12926, H12953, and H12955. The Bathymetric Attributed Grids (BAGs) for surveys H12528 and H12529 were downloaded from NOAA's National Centers for Environmental Information (NCEI) website for comparison with H12954. The finalized H12954 surface was compared to each junction survey by generating a difference surface with CARIS HIPS. At the time of writing, data from survey H12955 was still being processed. The Descriptive Reports for these respective surveys will include the junction analysis with H12954 Junction results between H12954 1-meter and H12528 4-meter bathy gridsSupportFiles\H12954_1m_H12528_4m_Junction.pngDescriptive statistics from the junction comparison with H12528 are presented in Figure 5. The minimum and maximum differences are associated with sound speed and tide zoning artifacts. It appears that the depth bias between the two surveys also result from the use of disparate tide zoning schemes and refraction. Prior survey H12528 used zoning correctors from the NWLON gauge Pascagoula NOAA Lab, MS (8741533) while survey H12954 was controlled from the NWLON gauge Dauphin Island (8735180). The bias resulting from the use of different zoning schemes is intensified in the area of the survey junction do to refraction experienced during the H12954 survey. David Evans and Associates, Inc.NH12528400002013Junction results between H12954 1-meter and H12529 4-meter bathy gridsSupportFiles\H12954_1m_H12529_4m_Junction.pngDescriptive statistics from the junction comparison with H12929 are presented in Figure 6. The surveys agree well, with minimum and maximum differences representative of surveys impacted by refraction and inaccuracies in discrete zoning methodsDavid Evans and Associates, Inc.NH12529400002013Junction results between H12954 1-meter and H12926 1-meter bathy gridsSupportFiles\H12954_1m_H12926_1m_Junction.pngDescriptive statistics from the junction comparison with H12926, which was also part of the OPR-J311-KR-16 survey project, are presented in Figure 7. The surveys agree well, with minimum and maximum differences representative of surveys impacted by refraction and inaccuracies in discrete zoning methods.David Evans and Associates, Inc.SH12926400002016Junction results between H12954 1-meter and H12953 1-meter bathy gridsSupportFiles\H12954_1m_H12953_1m_Junction.pngDescriptive statistics from the junction comparison with H12953, which was also part of the OPR-J311-KR-16 survey project, are presented in Figure 8. The surveys agree well, with minimum and maximum differences representative of surveys impacted by refraction and inaccuracies in discrete zoning methods.David Evans and Associates, Inc.SH12953400002016The junction analysis between H12955 and H12954 will be included in the H12955 DR.David Evans and Associates, Inc.EH12955400002016Tide and sound speed artifactsIn addition to the artifacts described above, occasional sound speed and discrete zoning artifacts approaching 20 centimeters in total magnitude are present in the survey data. Though these issues impacted some soundings, all data meet requirements outlined in the HSSD. CARIS HIPS 3D View of Rejected BiomassSupportFiles\H12954_Bio_Example.pngBiomass in Water ColumnA high volume of biomass (likely jellyfish as reported by the field party from visual observation) was present in the water column and observed in the sounding record on September 7 and 8, 2016 (DN251 and DN252). At times, sounding rejection was required to remove soundings on the biomass when impacting the CUBE surface. An example of the biomass' impact of the sounding data is depicted in Figure 9.DensityThe sounding density requirement of 80% of all nodes, populated with at least five soundings per node, was verified by exporting the density child layer of the finalized CUBE surface to an ASCII text file and compiling statistics on the density values. More than 98% of all final CUBE surface nodes contained five or more soundings. Survey speeds were maintained to meet or exceed along-track sounding density and side scan sonar ensonification requirements. Side scan mosaics were thoroughly reviewed for holidays and areas of poor quality coverage due to biomass, vessel wakes, or other factors. A fill plan was created in order to acquire side scan data where holidays and significant poor quality coverage existed. Side scan sonar contacts were developed with multibeam sonar to obtain a least depth of the contact using Complete Coverage requirements.Navigation Data GapsPeriodically, survey lines contained navigation gaps which were likely caused by a Hypack write delay during acquisition. Survey lines containing navigation data gaps greater than one second were updated with real-time DGPS/Inertial position data extracted from the POS/MV .000 files. The following survey line uses real-time navigation from .000 files: 2016BL2521827 and 2016BL2522014. Differential Correction OutagesThe differential correction signal received by the POS/MV 320 (primary positioning system) experienced several outages during acquisition on September 11, 2016 (DN255). These outages were detected because of alarms preconfigured in the acquisition system which would notify the hydrographic crew that the signal from the differential beacon had been lost. Data acquired without differential corrections were rejected using the 'Break Interpolation' option in the HIPS navigation editor and the resulting holidays were filled on a later date. Portions of the following lines were rejected due to differential correction outages: 2016BL2550359 2016BL2550817 2016BL2551142 2016BL2551740 2016BL2551814 Multibeam backscatter was logged in Hypack 7K format and included with the H12954 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. The survey data meets or exceeds requirements as set forth in the NOS Hydrographic Surveys and Specifications Deliverables Manual, Statement of Work, and Hydrographic Survey Project Instructions. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required.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.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.2016-11-03OPR-J311-KR-16 Data Acquisition and Processing ReportNSPS/THSOA Certified Hydrographer, Chief of Party2017-03-07Jonathan L. Dasler, PE, PLS, CHNSPS/THSOA Certified Hydrographer, Charting Manager / Project Manager2017-03-07Jason Creech, CHMBES Data Processing Manager2017-03-07Kathleen SchachtLead Hydrographer2017-03-07David T. Moehl, CH, LSIT