OPR-J311-KR-14 Western Vicinity of Lake Borgne Western Vicinity of Lake Borgne David Evans and Associates, Inc. H12721 7 String 7NM Northwest of Shoalwater Bay Louisiana United States 40000 2015 Jonathan L. Dasler, PE, PLS, CH Basic Hydrographic Survey 2014-08-29 2015-01-21 2015-06-02 Reson 7125 SV2 EdgeTech 4200-HF meters Universal Transverse Mercator (UTM) UTC Atlantic Hydrographic Branch NAD83, UTM Zone 16, 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. Contractor David Evans and Associates, Inc. (DEA) conducted hydrographic survey operations in Chandeleur Sound approximately seven nautical miles northwest of Shoalwater Bay. Survey H12721 was conducted in accordance with the Statement of Work (July 9, 2014) and Hydrographic Survey Project Instructions (August 29, 2014). The Hydrographic Survey Project Instructions reference the National Ocean Service (NOS) Hydrographic Surveys Specifications and Deliverables Manual (HSSD), April 2014 as the technical requirements for this project. 29.984880 89.027482 29.885003 88.928805 OPR-J311-KR-14 Assigned Survey Areas SupportFiles/H12721_AssignedSurveyAreas.png Survey Limits were acquired in accordance with the requirements in the Project Instructions and the HSSD. The purpose of this project is to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products. This project is located in an area subject to the influence of hurricanes on an annual basis, thus producing a very dynamic environment requiring frequent re-surveying. In addition, the tug and tow industry will be re-routed to the west of the Chandeleur Islands due to a Gulf Intracoastal Waterway West (GIWW) closure in the Summer of 2015. A large portion of the proposed alternative route for the tug and tow industry lies within the southern portion of this project area. This project will cover approximately 129 SNM of emerging critical areas and 4.5 SNM of priority 2 areas as identified in the 2012 NOAA Hydrographic Survey Priorities (NHSP). The project area is located in the vicinity of Lake Borgne, the Gulfport Sound Channel, and west of the Chandeleur Islands. The entire survey is adequate to supersede previous data. The survey consisted of 200% side scan sonar coverage with concurrent multibeam echosounder (MBES) and backscatter using the Set Line Spacing coverage technique. Significant side scan sonar contacts were developed with multibeam sonar to meet Object Detection coverage requirements for multibeam surveys. This inshore limit of the survey was defined as the farthest offshore of either the surveyed 4-meter depth contour or the Navigable Area Limit Line (NALL) defined in the OPR-J311-KR-14 Project Reference File (PRF). DEA received a waiver to use the full sonar range when the towfish altitude was less than 8% of the range scale when operating at the 50-meter range scale. This waiver removed the minimum towfish height requirement at the 50-meter range scale as specified in Section 6.1.2.3 of the HSSD. A copy of the email correspondence granting this waiver is included in OPR-J311-KR-14 Project Correspondence. H12721 Survey Outline SupportFiles/H12721_SurveyOutline.png S/V Blake 0 4.11 0 51.92 0 1318.37 0 112.62 0 0.0 4.11 0.0 51.92 0.0 1318.37 0.0 112.62 0.0 8.52 6 0 0 0 0 28.42 2015-01-21 2015-01-22 2015-01-24 2015-01-25 2015-01-28 2015-01-29 2015-01-30 2015-02-01 2015-02-02 2015-02-04 2015-02-06 2015-02-07 2015-02-08 2015-02-09 2015-02-10 2015-02-11 2015-02-12 2015-02-13 2015-02-14 2015-02-15 2015-02-16 2015-03-11 2015-04-09 2015-04-10 2015-06-02 The OPR-J311-KR-14 Data Acquisition and Processing Report (DAPR), previously submitted with survey H12708, details equipment and vessel information as well as data acquisition and processing procedures used during this survey. There were no vessel or equipment configurations used during data acquisition that deviated from those described in the DAPR. S/V Blake 83 4.5 S/V Blake SupportFiles/SV_Blake.png Reson 7125 SV2 MBES Edgetech 4200-HF SSS Applanix POS/MV 320 v4 Positioning & Attitude Rolls Royce MVP30-350 with AML Micro SVP&T Primary Sound Speed Profiler AML Micro SV Exchange Surface Sound Speed Sea-Bird Electronics SEACAT SBE 19-03 CTD Secondary Sound Speed Profiler AML SV Plus V2 Secondary Sound Speed Profiler Crosslines were run in a direction perpendicular to main scheme lines across the entire surveyed area, providing a good representation for analysis of consistency. All crosslines were used for crossline comparisons. 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 4-meter CUBE surface encompassing mainscheme data for the entire survey area. The QC Report tabular output and plot are included in Separate II Digital Data. The results of the analysis meet the requirements as stated in the 2014 HSSD. Additional crossline analysis was performed by computing a 4-meter CUBE surface from the crossline data. The surface was then differenced from a 4-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. All outliers from the difference analysis were reviewed in HIPS subset editor and found to result from a combination of sound speed artifacts in the outer beams and tide zoning errors. H12721 Crossline Differences SupportFiles/H12721_XL_MS.png 0.000 0.102 S/V Blake n/a 1 0.5 Additional discussion of these parameters is included in the DAPR. During surface finalization in HIPS, the "greater of the two” 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 4-meter Set Line Spacing multibeam surface range from 0.209 meters to 0.334 meters with a standard deviation of 0.002 meters. The uncertainty values of all nodes in the finalized 50-centimeter Object Detection multibeam surface range from 0.209 meters to 0.994 meters with a standard deviation of 0.012 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 4-meter Set Line Spacing multibeam surface, the allowable uncertainty utilized ranges from 41% to 66%. The mean allowable uncertainty for the surface is 42% with a standard deviation of 0.004. For the 50-centimeter Object Detection multibeam surface, the allowable uncertainty utilized ranges from 41% to 193%. The mean allowable uncertainty for the surface is 42% with a standard deviation of 0.024. In total 101 nodes out of 176,973 fail to meet specification. Nodes that were reported out of specification were coincident with areas of high depth standard deviation over significant features with steep slopes. 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. Survey H12721 junctions with surveys H12711, H12712, H12720, H12722 and D00140. Surveys H12711, H12712, H12720, and H12722 were also performed by DEA as part of project OPR-J311-KR-14. Prior survey D00140 was a hydrographic reconnaissance survey which used a vertical beam echosounder with 1,000-meter line spacing to evaluate chart adequacy. The Bathymetric Attributed Grid (BAG) for survey D00140 was downloaded from NOAA's National Geophysical Data Center (NGDC) website for comparison with H12721. The 4-meter finalized H12721 surface was compared to each junction survey by generating a difference surface with CARIS Base Editor. H12711 40000 2014 David Evans and Associates, Inc. NE Results from the junction analysis are shown in Figure 5. The minimum and maximum differences are associated with sound speed and tide zoning artifacts. Junction results between H12721 and H12711 4-meter bathy grids SupportFiles\H12721_H12711_4m_Junction.png H12712 40000 2014 David Evans and Associates, Inc. N Results from the junction analysis are shown in Figure 6. The minimum and maximum differences are associated with sound speed and tide zoning artifacts. Junction results between H12721 and H12712 4-meter bathy grids SupportFiles\H12721_H12712_4m_Junction.png H12720 40000 2014 David Evans and Associates, Inc. E Results from the junction analysis are shown in Figure 7. The minimum and maximum differences are associated with sound speed and tide zoning artifacts. Junction results between H12721 and H12720 4-meter bathy grids SupportFiles\H12721_H12720_4m_Junction.png H12722 40000 2015 David Evans and Associates, Inc. S The junction analysis between H12721 and H12722 will be included in the H12722 DR. D00140 20000 2008 Terrasond, Ltd. S The entire H12721 survey area junctions with prior hydrographic reconnaissance survey D00140. The maximum and minimum reported differences appear to be related to a combination of sound speed and tide zoning artifacts in areas where sediment migration has occurred since the prior survey. Results from this analysis are shown in Figure 8. Junction results between H12721 4-meter and D00140 5-meter bathy grids SupportFiles/H12721_D00140_5m_Junction.png Quality 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. None Exist There were no conditions or deficiencies that affected equipment operational effectiveness. Tide Zoning Artifacts The survey area, which lies in the Chandeleur Sound and is protected by the Chandeleur Islands, is 50 to 60 nautical miles from the controlling NWLON (National Water Level Observation Network) stations at Bay Waveland Yacht Club and Pascagoula NOAA Lab. Vertical errors resulting from the limitations of tide zoning are visible in the data. These errors generally range from 10 to 15 centimeters, but in some extreme cases exceed 30 centimeters. This vertical offset is within the typical error contribution of 20 to 45 centimeters for tides and water levels. The largest contributing factor to water level errors in the Chandeleur Sound is meteorological influences which cannot be accounted for by zoning. Recommendations were made in the Descriptive Report for Tidal Zoning submitted with prior survey D00140 that future surveys in this area use a subordinate gauge near the Chandeleur Islands. The hydrographer also recommends that future surveys in this area use water level corrections from local subordinate gauges or rely on ellipsoidally referenced survey (ERS) methodology for vertical control. Example of tide zoning artifact seen within H12721 SupportFiles/H12721_Tide_Zoning_Error.png Side Scan Sonar Data Gaps Additional side scan sonar acquisition occurred on June 2, 2015 (DN153) to fill previously unknown coverage holidays. This data acquisition occurred after the survey had been reported as complete. Data holidays were caused by missing ping datagrams in the XTF files and masked by default settings in the side scan sonar processing software. The missing sonar pings may have been caused by a bad solder on one of the SSS topside unit boards. SonarWiz is set to move pings and navigation points when it detects a gap in coverage in order to prevent an along-track holiday. This issue impacted survey line 2015BL0390103. The Project Contracting Officer’s Representative and Contracting Officer’s Technical Representative were notified about this issue. 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. There are six sound speed profiles which are more than 250 meters outside of the survey area. These profiles were acquired with the survey vessel’s MVP at the ends of survey lines prior to or after a line turn. Casts are valid and have been applied to hydrography. Profile names: 1/22/2015 6:26, 1/29/2015 22:58, 2/1/2015 14:38, 2/4/2015 12:06, 2/15/2015 23:06 and 3/11/2015 13:13. Survey speeds were maintained to meet or exceed along-track sounding density and side scan sonar ensonification requirements. Where 200% side scan coverage was required, demonstration of 200% coverage was achieved by producing two separate 100% 1 meter resolution mosaics. 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. Significant side scan sonar contacts were developed with multibeam sonar to obtain a least depth of the contact using multibeam Object Detection coverage requirements. Density The multibeam sonar Set Line Spacing sounding density requirement of 95% of all nodes populated with at least three soundings 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 99.8% of all final CUBE surface nodes contained three or more soundings. Density statistics for all individual item investigation surfaces was reviewed and surpassed the requirement 95% of all nodes populated with at least five soundings. Data reduction procedures for survey H12721 are detailed in the DAPR. Since submitting the DAPR the S/V Blake’s MRU Alignment values, which are used in TPU computations, have been updated. These values are reported in Table 6 of the DAPR and DAPR Appendix II and have been included in Figure 10 of this report. A summary of the multibeam processing logs is included Separate I Acquisition and Processing Logs of this report. Revised S/V Blake MRU Alignment Values SupportFiles/SV Blake MRU Alignment DAPR revision.png No additional calibration tests were conducted beyond those discussed in the DAPR. Multibeam backscatter was logged in Hypack 7K format and included with the H12721 digital deliverables. Data were processed periodically in CARIS HIPS to evaluate backscatter quality but the processed data is not included with the deliverables. CARIS HIPS 8.1 0 13 2015-06-07 Processing 5.3.2 H12721_MB_4m_MLLW CUBE 4.0 3.95 6.23 NOAA_4m Multibeam sonar Set Line Spacing Coverage H12721_MB_4m_MLLW_Final CUBE 4.0 3.70 6.23 NOAA_4m Finalized Multibeam sonar Set Line Spacing coverage H12721_MB_50cm_MLLW_combined CUBE 50 4.28 5.97 NOAA_0.5m Object Detection Coverage H12721_MB_50cm_MLLW_combined_Final CUBE 50 3.70 5.97 NOAA_0.5m Finalized Object Detection Coverage H12721_100Percent Mosaic 1.0 N/A First 100- percent coverage H12721_200Percent Mosaic 1.0 N/A Second 100- percent coverage Bathymetric grids were created relative to Mean Lower Low Water (MLLW) in CUBE format using Set Line Spacing and Object Detection resolution requirements as described in the HSSD. The 50-centimeter combined surface includes all investigation data at object detection resolution. Field sheets and surfaces were also submitted for all significant individual investigations. The name of the investigation field sheets correspond to the primary side scan sonar contact name. Least depths for all significant contact investigations were added to the final surface with a designated sounding. Additional designated soundings were added to depth surfaces as necessary in order to accurately represent the seafloor in accordance with the NOS HSSD. A complete description of the horizontal and vertical control for survey H12721 can be found in the OPR-J311-KR-14 Horizontal and Vertical Control Report (HVCR), submitted under a separate cover. A summary of horizontal and vertical control for this survey follows. Mean Lower Low Water Pascagoula NOAA Lab, MS 8741533 Bay Waveland Yacht Club, MS 8747437 8741533.tid Verified Observed 8747437.tid Verified Observed J311KR2014CORP_rev2.zdf Final North American Datum of 1983 (NAD83) NAD83 UTM Zone 16 North English Turn, LA (293 kHz) Eglin Air Force Base, FL (295 kHz) During survey operations, some Differential Global Positioning System (DGPS) outages from the primary beacon (293 kHz) occurred. The system was manually switched to the secondary beacon (295 kHz) when the primary signal was lost. No data was acquired during DGPS beacon outages. The majority of the chart comparison was performed by comparing H12721 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 RNCs covering the survey area to the corresponding ENCs 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. 11363 1 80000 44 2013-02 2015-04-28 2015-05-02 Coastal chart 11363 was compared to US4LA34M within the H12721 survey area. No differences were observed between the charts. 11373 1 80000 52 2015-05 2015-05-01 2015-05-01 A section of coastal chart 11373 overlaps with charts US4LA34M and 11363 at the northern end of the survey area. The only difference observed was a minor discrepancy in the portrayal of a 12-foot sounding and 12-foot contour at the southern border of 11373. US4LA34M 80000 29 2015-01-06 2015-05-11 false In general, surveyed depths are between 0 to 5 feet deeper than charted. Depth Difference between H12721 and chart US4LA34M SupportFiles/H12721_ChartComp_US4.png No AWOIS Items were assigned for this survey. No Maritime Boundary Points were assigned for this survey. The Obstruction PA (Position Approximate) charted at the northern end of the survey area has been disproved by the survey. The feature has been included in the Final Feature File (FFF) with a description of ‘Delete’. The Obstruction PA has been included in the FFF with a description of ‘Delete’. This feature was also disproved by survey H12712 (Project OPR-J311-KR-14) and included in the H12712 FFF. The Wreck showing Masts PA charted in the northeast corner of the survey area has been disproved by the survey. The Wreck showing Masts PA has been included in the FFF with a description of ‘Delete’. The Wreck showing Masts PA charted in the southeast corner of the survey area has been disproved by the survey. The Wreck showing Masts PA has been included in the FFF with a description of ‘Delete’. The Wreck showing Masts PA charted along the western edge of the survey area has been disproved by the survey. Survey acquisition was extended to the west of the assigned limits to include coverage over this charted feature. The Wreck showing Masts PA has been included in the FFF with a description of ‘Delete’. All uncharted features are portrayed in the FFF as surveyed and attributed with the description of ‘New’. 1 One Danger to Navigation (DtoN) was submitted for this survey. This DtoN was added to the charts using preliminary survey data, including the use of predicted tides. Shoals depicted by the 12-foot contour are charted along the western edge and the northeastern corner of the survey area. Surveyed depths in these areas are deeper than charted with no soundings of 12 feet or shoaler located by the survey. The H12721 survey area does not contain any anchorage areas, maintained navigation channels or channel lines. Six bottom samples were acquired on April 9, 2015 (DN099) and April 10, 2015 (DN100). The sampling plan followed suggested sample locations included in the PRF provided by the Hydrographic Surveys Division. A shoreline investigation was not performed for this survey. The OPR-J311-KR-14 Project Instructions required a limited shoreline verification but the H12721 survey area does not junction with shoreline. Other than the previously mentioned junction analysis no other comparisons with prior surveys were conducted. No Aids to Navigation (AtoNs) were charted or located within the H12721 survey area. The position of the Mobil St. Benard Mooring Dolphin Lights (No. 13760) published in the USCG Light List (Volume IV - Gulf of Mexico) falls within the H12721 survey area. No feature was observed during survey operations in this location. The position published for this light is suspect and should be verified by the USCG. According to the Light List, this feature falls between Head of Passes and New Orleans and is charted on Chart 11364. It appears that the published latitude for these lights should be 089-58-30.000W instead of 088-58-30.000W. Mobil St. Benard Mooring Dolphin Lights in the USCG Light List SupportFiles/H12721_LightListError.png There were no overhead bridges, cables, or other structures which would impact overhead clearance in the survey area. No submarine cables or tunnels were charted or located within the H12721 survey area. A section of an uncharted submarine pipeline was discovered during survey operations and reported to AHB and the NOAA Central Gulf Coast Navigation Manager. While not charted, the Louisiana Department of Natural Resource’s Strategic Online Natural Resources Information System (SONRIS) depicts a pipeline in this location which extends through the southwest corner of the H12721 survey area. The pipeline owner, who was contacted by the Navigation Manager, reported that the pipeline was in the process of being removed. Correspondence related to this issue is included in Appendix II of this report. The section of pipeline that was visible in the survey has been portrayed in the FFF as a pipeline feature. The feature was included to facilitate data review and is not recommended for charting. There were no ferry routes or terminals within the survey area. No platforms were charted or located within the H12721 survey area. There was no additional information of scientific or practical value observed during the survey. There were no unusual submarine features or anomalous tidal or environmental conditions observed during the survey that impacted the quality of the survey or worthy of charting. No construction or dredging activities were observed during survey operations. The hydrographer recommends that future surveys in Chandeleur Sound extend to the 2-meter contour. Vessels transiting through Chandeleur Sound do so in waters shallower than this survey’s inshore depth limit. 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 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. Jonathan L. Dasler, PE, PLS, CH NSPS/THSOA Certified Hydrographer, Chief of Party 2015-07-13 Jason Creech, CH NSPS/THSOA Certified Hydrographer, Lead Hydrographer 2015-07-13 Data Acquisition and Processing Report 2015-04-24