OPR-J348-KR-13 Approaches to Mississippi Sound Approaches to Mississippi Sound David Evans & Associates, Inc. H12528 1 Vicinity of North Chandeleur Islands Mississippi United States 40000 2013 Jonathan L. Dasler, PE, PLS, CH Basic Hydrographic Survey 2013-03-25 2013-03-15 2013-10-27 RESON 7125 EdgeTech 4200-FS meters Universal Transverse Mercator (UTM) UTC Atlantic Hydrographic Branch NAD 83, 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 the Approaches to Mississippi Sound, MS in the vicinity of the North Chandeleur Islands. Survey H12528 was conducted in accordance with the Statement of Work (April 29, 2013) and Hydrographic Survey Project Instructions (revised) (March 25, 2013). The Hydrographic Survey Project Instructions reference the 2012 Hydrographic Surveys Specifications and Deliverables (HSSD), but the OPR-J348-KR-13 surveys were performed using the 2013 HSSD with the exception of the holiday specification for Set Line Spacing Surveys (Section 5.2.2.3) which uses the 2012 specification of no gaps in the entire multibeam swath greater than 3 nodes along track. This modification was approved by Hydrographic Surveys Division (HSD) staff. 30.102991 88.941708 29.975496 88.769648 1 OPR-J348-KR-13 Assigned Survey Areas SupportFiles/H12528_AssignedSurveyAreas.png The purpose of this survey is to provide National Oceanic Atmospheric Administration (NOAA) with modern, accurate hydrographic survey data with which to update nautical charts of the assigned area. The entire survey is adequate to supersede previous data. Survey Limits were acquired in accordance with the requirements in the Project Instructions and the HSSD. 2 H12528 Survey Outline SupportFiles/H12528_SurveyOutline.png The survey consisted of 200% side scan sonar coverage with concurrent multibeam in waters 4 meters and deeper. The survey polygon depicted in the Project Reference File (PRF) OPR-J348-KR-13_PRF.000, which was included with the Hydrographic Survey Project Instructions (March 25, 2013 revised), was used to define the limits for each survey. The survey was conducted over 80-meter and 130-meter set line spacing per 100% coverage (50-meter and 75-meter side scan sonar ranges, respectively). Automated Wreck and Obstruction Information System (AWOIS) items identified by side scan sonar and significant side scan sonar contacts were developed with multibeam sonar to meet object detection coverage requirements for multibeam surveys. The coverage area totaled 33.5 square nautical miles using a combination of side scan and multibeam survey methods. Areas within the assigned survey polygon included in the PRF that were inshore of the surveyed 4-meter contour were not surveyed. A waiver was granted by HSD staff via email on November 8, 2013 eliminating the need to reduce effective range based on side scan towfish height (HSSD 6.1.2.3) within the search radius of AWOIS #14960 when data were acquired inshore of the 4-meter inshore limit. This waiver allowed the full disproval of AWOIS #14960 as portions of the search radius extended inshore of the surveyed 4-meter curve. A copy of this email is included in Appendix II. 2013-03-15 2013-03-17 2013-03-18 2013-03-27 2013-03-28 2013-03-29 2013-03-30 2013-04-01 2013-04-06 2013-04-07 2013-04-15 2013-04-24 2013-04-27 2013-04-28 2013-04-29 2013-04-30 2013-05-07 2013-05-08 2013-06-12 2013-07-10 2013-07-12 2013-07-13 2013-07-26 2013-07-29 2013-07-30 2013-08-02 2013-08-03 2013-08-04 2013-08-07 2013-08-08 2013-10-14 2013-10-16 2013-10-24 2013-10-27 7 3 0 0 0 33.5 R/V Westerly 0 0 0 0 0 1200.1 0 102.6 0 0 0 0 0 0 1200.1 0 102.6 0 8.6 The OPR-J348-KR-13 Data Acquisition and Processing Report (DAPR) submitted under separate cover, 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. R/V Westerly 38 4.6 3 R/V Westerly SupportFiles/H12530_DR_Vessel_RV_Westerly.png RESON 7125-SV2 MBES Edgetech 4200-FS SSS AML Micro X / SV Xchange Surface Sound Speed Brooke Ocean MVP-30 with AML Micro SVPT Primary Sound Speed Profiler Sea-Bird SEACAT SBE-19 CTD Profiler Secondary Sound Speed Profiler Applanix POS/MV 320 v4 Positioning & Attitude 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 2013 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 CUBE surface comprised of all mainscheme, fill, and investigation data. The resultant difference surface was exported using the Base Surface to American Standard Code for Information Interchange (ASCII) function and statistics were compiled on the ASCII data. The crossline analysis included 378,859 node comparisons with an average difference of 0.01 meters and standard deviation of 0.034 meters. 0 0.074 R/V Westerly 1.000 1.000 0.500 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 surface 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 surfaces range from 0.19 meters to 0.38 meters with a standard deviation of 0.005 meters. The maximum uncertainty value is located along the edge of what appears to be a historic dredged area. The high standard deviation in the depth surface results from gridding data over this steeply sloping feature. 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. For the 4-meter surface the allowable uncertainty utilized ranges from 35% to 75%. The average allowable uncertainty for the surface is 37% with a standard deviation of 0.009. There are no values exceeding 100% which indicates that all nodes meet specification. Survey H12528 junctions with H12529 from project OPR-J348-KR-13 and with two prior NOAA surveys. Bathymetric Attributed Grids (BAGs) of these prior surveys were downloaded from NOAA's National Geophysical Data Center (NGDC) website for comparison. A 4-meter finalized H12528 surface, with no depth thresholds applied, was compared to the prior surveys by generating difference surfaces with CARIS Bathy DataBASE. The H12528 surface with no depth thresholds applied was created for quality control purposes and has not been submitted. H11514 40000 2005 NOAA Ship Thomas Jefferson NW In total 56,749 overlapping nodes were compared with differences ranging from -0.866 meters (H12528 shoaler than prior) to 5.541 meters (H12528 deeper than prior). The average difference was -0.012 meters with a standard deviation of 0.134 meters. The maximum difference of 5.541 meters occurred over an area with questionable gridded depths in the H11514 surface which were possibly caused by depth fliers in the prior survey. H11545 40000 2006 Terrasond, Ltd. NE In total 119,025 overlapping nodes were compared with differences ranging from -0.200 meters (H12528 shoaler than prior) to 0.404 meters (H12528 deeper than prior). The average difference was 0.06 meters with a standard deviation of 0.073 meters. H12529 40000 2013 David Evans and Associates, Inc. E At the time of writing, junction analysis with OPR-J348-KR-13 survey H12529 had not been completed. Junction analysis between H12528 and H12529 will be discussed in the H12529 Descriptive Report. Quality control is discussed in detail in Section B of the DAPR. The results from the positioning system comparison and bar-to-multibeam comparison are included in Separate I Acquisition and Processing Logs. The sound velocity profile (SVP) sensor weekly evaluation table can be found in Separate II Sound Speed Data 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. Submerged significant features identified during survey operations were noted in the acquisition logs, saved to Isis cursor log files, and then displayed during HIPS editing to act as a check during feature compilation. In addition to the field interpretation of side scan contacts, two independent post-processing reviews of the side scan data were conducted, and all significant contacts or potentially significant contacts tracked in a custom database. Exist As discussed in the DAPR, results of routine roll tests were added to the project vessel file to account for a minor instability of the mulitbeam mount. None Exist There were no other factors that affected corrections to soundings. Approximately 15-minute intervals. An ODOM Brooke Ocean Technologies’ MVP30 and a SeaBird Electronics SEACAT SBE-19 Conductivity, Temperature, and Depth (CTD) profiler were the primary instruments used to acquire sound speed readings during multibeam operations. Moving vessel profiler (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 speeds were maintained to meet or exceed along track coverage requirements throughout the survey. Demonstration of 200% side scan sonar 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. Multibeam data were acquired in conjunction with side scan sonar collection. A fill plan was created for all multibeam holidays greater than three nodes along track that extended across the entire swath. This requirement corresponds to the along track holiday specification in the 2012 HSSD (Section 5.2.2.3). 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 sounding density requirement of 95% of all nodes, populated with at least three soundings per node, was verified by exporting the density child layer of each CUBE surface to an ASCII text file and compiling statistics on the density values. More than 99.6% of all final CUBE surface nodes contained three or more soundings. Density statistics of an individual item investigation surface using Object Detection requirements was reviewed and surpassed the 95% requirement. Data reduction procedures for survey H12528 are detailed in the DAPR. The multibeam summary processing log is included Separate I Acquisition and Processing Logs of this report. No additional calibration tests were conducted beyond those discussed in the DAPR. Multibeam backscatter was logged in Hypack 7K format and included with the H12528 digital deliverables. Data were processed periodically in CARIS HIPS to evaluate backscatter quality but the processed data is not included with the deliverables. 5.3.2 H12528_MB_4m_MLLW CUBE 4.0 0 40 NOAA_4m Set Line Spacing Coverage H12528_MB_50cm_MLLW CUBE 0.5 0 22 NOAA_0.5m Object Detection Coverage H12528_100Percent Mosaic 1.0 N/A First 100-percent coverage H12528_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 NOS HSSD (April 2013). Depth thresholds were applied during surface finalization as defined in the NOS HSSD (April 2013). The 50-centimeter surface includes data at object detection resolution for a significant feature investigated with multibeam. In addition, a field sheet and surface was submitted for this investigation with the name of the investigation field sheet corresponding to the primary side scan sonar contact name. The least depth for the significant contact investigation was 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 H12528 can be found in the OPR-J348-KR-13 Horizontal and Vertical Control Report (HVCR), submitted under separate cover. A summary of horizontal and vertical control for this survey follows. Mean Lower Low Water Discrete Zoning Pascagoula NOAA Lab, MS 874-1533 8741533.tid Verified Observed OPSREVISED_J348KR2013CORP Final North American Datum of 1983 (NAD83) NAD83 UTM Zone 16 North English Turn, Louisiana (293 kHz) Eglin, Florida (295 kHz) During survey operations, some Differential Global Positioning System (DGPS) outages from the primary beacon (293 kHz) occurred. The system was set up to automatically switch to the secondary beacon (295 kHz) when the primary signal was lost. The majority of the chart comparison was performed by comparing H12528 depths to a digital surface generated from electronic navigational charts (ENCs) covering the survey area. A 50-meter product surface was then 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 4-meter CUBE surface. The chart comparison was conducted by creating and reviewing the resultant difference surface. The raster chart comparison was performed by comparing the raster navigational charts (RNCs) covering the survey area to the corresponding ENCs which were subsequently compared to H12528 using difference surface techniques. The electronic and raster versions of the relevant charts used during the comparison were reviewed to ensure that all USCG Local Notice to Mariners (LNM) issued during survey acquisition, impacting the survey area, were applied and addressed by this survey. 11363 55 80000 44 2013-02 2013-09-24 2013-10-05 Chart 11363 was compared to US4LA34M within the H12528 survey area. No differences between the raster navigational chart (RNC) and ENC were observed. Charted differences determined by comparing surveyed depths to a digital surface of US4LA34M are discussed in Section D.1.2. 11373 52 80000 50 2012-08 2013-09-24 2013-10-05 Chart 11373 was compared to US4LA34M and US4MS12M within the H12528 survey area. No differences between the RNC and ENC were observed other than minor differences in the placement of some soundings and contours. Charted differences determined by comparing surveyed depths to a digital surface of US4MS12M are discussed in Section D.1.2. 11366 2886 250000 15 2012-08 2013-09-24 2013-10-05 Chart 11366 corresponds to chart US3GC04M within the H12528 survey area. No differences between the RNC and ENC were observed. Charted differences in this area determined by comparing surveyed depths to a digital surface of US3GC04M are discussed in Section D.1.2. US4LA34M 80000 28 2012-05-01 2013-09-25 false Charts US4LA34M and US4MS12M, which are of the same scale and both cover the survey area, were merged prior to chart comparison. With the exception of significant changes at the northern end of the Chandeleur Islands surveyed depths from H12528 are generally 3 feet shoaler to 5 feet deeper than charted. There are areas that are up to 25 feet shoaler than charted and 15 feet deeper than charted at the northern end of the Chandeleur Islands. H12528 Dangers to Navigation (DtoNs) 1 and 2 were submitted to identify this area of shoaling. The chart was only updated with a series of shoal soundings from DtoN 1 which are unable to accurately depict the extent of the change in this area. 4 Depth Difference between H12528 and charts US4LA34M and US4MS12M SupportFiles/H12528_ChartComp_4Combined.png US4MS12M 80000 21 2012-11-09 2013-10-29 false The chart comparison with ENC US4MS12M was previously discussed with ENC US34LAM. US3GC04M 250000 49 2012-04-05 2013-10-30 false As with the large scale charts there are considerable differences of up to three fathoms between surveyed depths and the small scale chart along the northern end of the Chandeleur Islands. Surveyed depths are generally one fathom shoaler to one fathom deeper than charted over the remainder of the survey area. 5 Depth Difference between H12528 and chart US3GC04M SupportFiles/H12528_ChartComp_3G.png Three (3) AWOIS items were assigned for investigation within the survey H12528 area. AWOIS Item #7311 is listed as a sounding in the AWOIS database with no other supporting information on this item. A 43-foot sounding is charted on the largest scale chart (US4MS12M / 11373) at the location of AWOIS #7311. Surveyed soundings within the 200-meter AWOIS search radius range from 34 feet to 40 feet. No side scan sonar contacts were located within the search radius. AWOIS #7311 has been disproved by 200% side scan coverage and has been included in the Final Feature File as a $CSYMB object with a description of 'Delete'. It is recommended that the AWOIS database be updated with findings from the H12528 survey. AWOIS Item #14960 is charted (US4LA34M/11363/11373) as a wreck Position Approximate (PA) showing mast/ masts. Five (5) insignificant side scan sonar contacts were investigated with multibeam sonar within the 1000 meter search radius; none showing evidence of a wreck. Survey H12528 has disproved this item with 200% side scan coverage. It is recommended that the AWOIS database be updated with findings from the H12528 survey. The charted wreck representing AWOIS #14960 as depicted in the Composite Source File (CSF) has been included in the Final Feature File with a description of 'Delete'. AWOIS Item #15030 is charted (US4LA34M/11363/11373) as a wreck PA showing any portion of hull or superstructure. Multibeam sonar investigations were run on two insignificant side scan contacts observed just outside of the 200-meter search radius but no evidence of a wreck was observed. Survey H12528 has disproved this item with 200% side scan coverage. It is recommended that the AWOIS database be updated with findings from the H12528 survey. The charted wreck representing AWOIS #15030 as depicted in the CSF has been included in the Final Feature File with a description of 'Delete'. No Maritime Boundary Points were assigned for this survey. There are two charted features labeled as PA within the H12528 survey area. These features correspond to AWOIS #14960 and #15030 which have been previously discussed. There is also one Shoal PA note and one Shoaling reported PA note in the vicinity of the observed shoaling at the northern end of the Chandeleur Islands. The hydrographer recommends that these notes be removed when the results of this survey are applied to the charts. The survey area does not contain any submerged charted features labeled as Position Doubtful (PD) or Existence Doubtful (ED). Charted features assigned in the CSF are included in the H12528 File Feature File and denoted with the Assignment Flag of 'Assigned'. A new uncharted obstruction, submitted as H12528 DtoN 3, is discussed in Section D.1.7. 3 Three (3) DtoNs were reported for this survey and have been submitted to the Atlantic Hydrographic Branch (AHB). H12528 DtoNs 1 and 2 were submitted as a selection of shoal soundings which delineated shoaling at the northern end of the Chandeleur Islands. This shoaling is fully represented in the H12528 bathymetric surfaces included with the survey deliverables. DtoN 1 has been applied to the charts while DtoN 2 has not. H12528 DtoN 3, which has been applied to the charts, is included in the Final Feature File. DtoN 3 appears to be the remains of the Chandeleuer Island Lighthouse which was destroyed during Hurricane Katrina in 2005. Email correspondence with the Central Gulf Coast Navigation Manager on this subject is included in Appendix II. 6 Remains of the Chandeleuer Island Lighthouse SupportFiles/H12528_DtoN3_MBES_3D.png As previously discussed, significant shoaling was observed along the northern end of the Chandeleur Islands. The H12528 survey area does not contain any anchorage areas, maintained navigation channels or channel lines. The northern edge of survey area borders charted safety fairway (33 CFR 166.200). Seven (7) bottom samples were acquired on August 27, 2013 (DN 239). Approximate sample locations were included in the file PRF provided by the Hydrographic Surveys Division. The final sampling plan primarily used the provided locations with some modification of position to better characterize changes in bottom type delineated in the side scan imagery, and to avoid sampling in the vicinity of submerged infrastructure such as pipelines or platforms. A limited shoreline investigation was assigned in the OPR-J348-KR-13 Hydrographic Survey Project Instructions. The project CSF included assigned coastline and land area charted features which were inadvertently assigned by HSD staff during the creation of the CSF. An email with HSD staff from March 7, 2013 discussing this issue has been included in the OPR-J348-KR-13 Project Correspondence. No charted or uncharted baring or shoreline features were located within the H12528 survey area. Aside from previously discussed comparison to junction surveys H11514 and H11545 no other comparisons with prior surveys were conducted. No Aids to Navigation (AtoNs) were charted or located within the H12528 survey area. There were no overhead bridges, cables, or other structures which would impact overhead clearance in the survey area. No pipelines were charted or located within the H12528 survey area. There were no ferry routes or terminals within the survey area. No platforms were charted or located within the H12528 survey area. Refraction artifacts were visible in the side scan and multibeam data acquired along the Northern Chandeleur Islands as a result of the large volume of fresh water being released during flood events on the Mississippi and Pearl Rivers. Evidence of this issue was apparent in the sound speed profiles collected during acquisition. Survey operations were discontinued in this area until the rivers returned to a normal stage and the fresh water lens causing the refraction dissipated. 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. There were no construction or dredging activities observed during survey operations. There is evidence of past dredging activity along the western edge of the survey area adjacent to the Chandeleur Islands. This dredging may have been associated with mitigation efforts during the Deepwater Horizon oil spill. No 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 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 with the exception of deficiencies noted in the Descriptive Report. Jonathan L. Dasler, PE, PLS, CH NSPS/THSOA Certified Hydrographer, Chief of Party 2014-01-28 Jason Creech Lead Hydrographer 2014-01-28 Data Acquisition and Processing Report 2014-01-17