Kensington, SC (292 kHz)UTM Zone 17 NorthWorld Geodetic System of 1984: WGS84 (G1674)An SBAS (satellite base augmentation solution) subscription was utilized through Fugro Marinestar to achieve a post-processed precise point position (5P) solution. See the associated DAPR for technical details.Marinestar Subscription LicenseA satellite-based augmentation system (SBAS) subscription through Fugro Marinestar was utilized to obtain precise point positions and post-processed in POSPac MMS software to achieve improved accuracy solutions in the form of smoothed best estimate trajectory (SBET) files. See the associated DAPR for greater technical details. Given the Hassler requires a unique set of position data for both the port and starboard inertial measurement units (IMU) to create the SBET's, two (2) Marinestar subscription licenses are typically necessary to apply the required correction data. Licenses for both the port and starboard systems were procured for this project, however the license for the port system concluded on August 1, 2016 (DN 214) and was unable to be immediately renewed. Thus, as a temporary fix the Marinestar position data acquired for the starboard system from DN 223 through DN 232 was also applied to the port system. A unique hydrographic vessel file (.HVF) with the name FH_S250_PORT_Reson7125_STBD_IMU_512bms_400kHz_S7K_2016 was created to account for the horizontal offsets between starboard and port systems allowing for all processed data to be correctly georeferenced. Review of the data collected on those days shows all are within specifications as set forth by the 2016 HSSD.WGS84 Horizontal DatumThe horizontal datum requirement stated in the 2016 HSSD Section 2.1 was given as World Geodetic System of 1984 (WGS84 (G1674). The field unit followed this requirement, however after data acquisition had already begun, Hydrographic Technical Directive #2016-03 was published rescinding this requirement and re-established the horizontal datum requirement to be the North American Datum of 1983 (NAD83). Subsequent email correspondence from the Chief of HSD Operations stated that any survey initiated in the WGS84 horizontal datum may be continued for the duration of the project and or sheet.Discrete Zoned TidesAll soundings submitted as H12894 are reduced to MLLW using documented VDatum techniques as required by the Project Instructions. However, if it is deemed necessary to change the water level reduction method to discrete zoning the following additional information may be useful: 1) The National Water Level Observation Network (NWLON) station serving as datum control for this survey is Springmaid Pier, SC (8661070). 2) The verified water level file (8661070.tid) has been loaded for all data, but not applied in the final merge of data. GPS tides were applied in the final merge of all data as required for ellipsoidally referenced surveys. 3) The submitted tide corrector (OPRG309FH2016CORP.zdf) is the preliminary zoning file that was accepted as final per final tide note, submitted in Appendix I. This file has been loaded to all CARIS lines submitted as H12894. 4) A request for final approved tides was sent to COOPS on 31 August, 2016. The final tide note was received on 7 September 2016, stating that preliminary zoning is accepted as the final zoning for project OPR-G309-FH-16-02, H12894, during the time period between 12 July 2016 and 19 August 2016.Mean Lower Low WaterAll soundings submitted for H12894 have been reduced to MLLW using documented VDatum techniques.G309FH16ExpandedProjectArea_xyWGS84-MLLW_geoid12bERS via VDATUMAdditional information discussing the vertical or horizontal control for this survey can be found in the accompanying ERS Checkline and ERS Capability Memo(s).The purpose of this project is to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products. The project is based on a request from an Atlantic Coast Port Access Route Study conducted by Pacific Northwest National Laboratory at the request of the U.S. Coast Guard to delineate traffic corridors using Automated Identification Systems (AIS). This project will improve the chart for traffic navigating from Port to Port along the Atlantic Ocean Channel.S2500000055.581093.49000000055.585.081093.4900Mainscheme survey lines are normally run with a dual-head multibeam echosounder with independent port and starboard inertial measurement units (IMU) used for positioning. Linear nautical miles were calculated using statistics from the port system. Due to only the starboard GNSS positioning system having licensing with the Fugro Marinestar GNSS corrector subscription after DN 213 (07/31/2016), starboard IMU data was applied to port bathymetry data for DN 214 (08/01/2016) through DN 232 (08/19/2016). Data from these dates were processed in CARIS HIPS with a unique vessel file named: FH_S250_PORT_Reson7125_STBD_IMU_512bms_400kHz_S7K_2016. See DR Section 3.3.1 for more details.2016-07-312016-08-012016-08-022016-08-032016-08-042016-08-052016-08-092016-08-102016-08-112016-08-152016-08-162016-08-19600084.43All waters in survey area. Refer to HSSD Section 5.2.2.3Complete Multibeam with Backscatter.Survey coverage was in accordance with the requirements listed above and in the HSSD.Survey layout for OPR-G309-FH-16 overlaying RNC 11520.SupportFiles\H12894_ProjectLayout.pngThe entire survey is adequate to supersede previous data.H12894 Survey LimitsSupportFiles\H12894_SurveyLimits.pngSurvey H12894 was conducted in Long Bay, with a sublocality of 56 miles East of Georgetown Light as shown in Figure 1.33.0545978.066668888933.267826944478.3265741667Survey limits were acquired in accordance with the requirements in the Project Instructions and the HSSD.NOAA56 Miles East of Georgetown LightUnited States40000North CarolinaSouth Carolina2H12894Approaches to WilmingtonNOAA Ship FERDINAND R. HASSLEROPR-G309-FH-16Approaches to WilmingtonmetersMultibeam Echo SounderMultibeam Echo Sounder BackscatterUniversal Transverse Mercator (UTM)LCDR Matthew Jaskoski, NOAA2016-06-292016-07-312016-08-19Navigable Area2016Atlantic Hydrographic BranchUTCChief of Party2017-02-17LCDR Matthew Jaskoski, NOAAField Operations Officer2017-02-17LT Nicholas Morgan, NOAASheet Manager2017-02-17PS Jeff MarshallAs Chief of Party, field operations for this hydrographic survey were conducted under the direct supervision of Commanding Officer, LCDR Matthew Jaskoski, with frequent personal checks of progress and adequacy. I have reviewed the attached survey data and reports.The survey data meets or exceeds requirements as set forth in the NOS Hydrographic Surveys and Specifications Deliverables Manual, Field Procedures Manual, Letter Instructions, and all HSD Technical Directives. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required with the exception of deficiencies noted in the Descriptive Report.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.Backscatter was logged in RESON datagram 7008 snippets record in the raw .s7k files. The .s7k file also holds the navigation record and bottom detections for all lines of survey H12894. The files were paired with the CARIS HDCS data, imported, and processed using Fledermaus Geocoder Toolbox (FMGT). The FMGT projects and backscatter mosaic imagery is included in the field submission. The processed mosaic is formated as a geo-referenced tiff image per specifications. The following information is provided as metadata for the processing branch: Backscatter data processing and mosaicking performed in Fledermaus FMGT version 7.6.3 using Reson De-TVG plugins where appropriate. Backscatter data has a histogram range of 10 to -70dB Backscatter data is provided in separate layers broken down by survey vessel hull number and sonar operating frequency. H12894_S250_Port_400kHz | 4m resolution mosaic | Absorption Coefficient = 100dB/km H12894_S250_Stbd_400kHz | 4m resolution mosaic | Absorption Coefficient = 100dB/km Sources of error data applied during CARIS processing.SupportFiles\H12894_uncertainty_source.pngTwo (2) tidal models were available for water level corrections associated with survey H12894. A discrete tide zone file, produced by CO-OPS for project OPR-G309-FH-16, was provided to the field unit. Additionally, a vertical datum transformation (VDatum) model was delivered to the field unit in the project instructions . All data for survey H12894 were reduced to MLLW via VDatum. This model functioned as a gridded separation model for GPS tide computations with a 0.148 meter uncertainty. Final TPU calculations are derived from the following sources: VDatum separation model, sound velocity (MVP, CTD and surface sound velocimeter), HVF uncertainties, and SBET post processed uncertainty. Error data sources applied through CARIS processing software are listed in Figure 6. The ODIM Brooke Ocean Moving Vessel Profiler (MVP) experienced intermittent mechanical issues during the course of H12894 data acquisition. When not operational, a Sea-Bird CTD was used to conduct static casts to model the water column sound speed profile approximately every two to four hours. Frequency was dependent on changes observed in refraction errors within processed data and comparison of previous profile data. MVP cast data were used on DN 215 through 217. CTD cast data were used in data processing for the second half of DN 217 through DN 232.S250110.50.1480.01ERS via VDATUMH12894 MBES crossline data overlaid on mainscheme data. The legend represents the difference surface values. SupportFiles\H12894_main_minus_xln_overview.pngH12894 crossline difference statistics: mainscheme minus crossline.SupportFiles\H12894_2m_main_minus_xln_distribution.pngThe ratio of crossline to main scheme mileage was calculated to be 5.08% which is within specifications set forth in Section 5.2.4.3 of the 2016 HSSD. A geographic plot of crosslines is shown in Figure 4. To evaluate crossline agreement, two 2-meter surfaces were created: one from crossline depths, the other from mainscheme depths. These two surfaces were differenced using CARIS BASE Editor and are found to be in excellent agreement. See Figure 5. Nodes totaling greater than 4.9 million have a difference value range between -6.21 meters and 3.59 meters. The statistical analysis of the differences between the mainscheme and crossline surfaces is shown in Figure 5. The average difference between the surfaces is -0.03 meters with a standard deviation of 0.13 meters. Ninety-five percent of nodes agree within +/- 0.25 meters of the mean. Three hundred sixty nine (369) nodes exhibit a difference exceeding +/- 1.0 m. These nodes represent deep fliers that were included in the 2 meter crossline surface, but were not included in the 2 meter mainscheme surface. Further, these aberrant nodes are not included in the 2 meter finalized surface submitted as the main deliverable.As noted in prior sections, the ODIM Brooke Ocean MVP experienced intermittent mechanical issues during the course of data acquisition and both moving and static casts (via Sea-Bird CTD) were collected. These sound speed measurements were collected using the MVP-200 and Sea-Bird CTD approximately every one to four hours. The mean sampling frequency for all casts was 73 minutes, while the shortest interval was 16 minutes and the longest interval 234 minutes (nearly 6 hours).H12894 sound speed profile locations.SupportFiles\H12894_SVP_Locations.pngSound speed profiles for Survey H12894.SupportFiles\H12894_SVP_ALL.pngRay tracing uncertainty analysis for all H12894 sound speed profiles.SupportFiles\H12894_SVP_Compare.pngA total of 119 sound speed measurements were taken within the boundaries of H12894. One cast acquired on DN 231 was collected outside the survey bounds while acquiring mainscheme data on adjacent sheet H12895. See Figure 10. However these data were also applied to H12894 as the ship shifted operations back to acquiring holiday and feature data on H12894. Given the ship was required to halt operations to collect static CTD due to mechanical failure of the MVP and the water column profile was suitably consistent over the spatial and temporal extents, it was deemed acceptable to include the outside casts for processing in H12894. A significant, but rather consistent thermocline existed in the water column throughout the period of data collection. This mid-water column thermocline which resided between approximately 12 and 25 meters demonstrated sound speed variations of up to 15 meters per second. See Figure 11. Cast frequency was appropriate however, as only some minor refraction errors are observed in outer beam data having little impact on the submitted 2 m finalized grid. This is further evidenced via a ray tracing uncertainty analysis identifying casts that exceeded the allowance for refraction as defined in 2016 HSSD Section 5.2.3.5. As shown in Figure 12. The blue lines in the graph are consecutive cast comparisons and the red dots are the allowable vertical error due to refraction. In cases where the blue line exceeds the red dots, those are examples of where the estimations show the allowable refraction error is being exceeded. As shown, refraction issues do exceed allowable error tolerances and the submitted surface remains within 2016 HSSD specifications. Depending on cast frequency, sound speed corrections were applied in CARIS HIPS/SIPS using the Nearest in Distance Within Time (NIDWT) selection with time frequency varying between 2 and 4 hours.None ExistThere were no other factors that affected corrections to soundings.Contemporary junction surveys associated with survey H12894.SupportFiles\H12894_Junctions.pngThree (3) contemporary surveys of the same project junction with H12894. H12893 adjoins H12894 to the southwest and H12895 to the northeast. See Figure 7. At the time of submission, only H12893 and H12895 were available for comparison. Data had not been acquired on H12928 to the south at the time of H12894 survey submission and thus no junction analysis was completed. The junction analysis between H12893 and H12894 was also submitted as part of the H12893 DR deliverable.Difference surface statistics for H12894 and H12895.SupportFiles\H12894_H12895_junction_diff_stats.pngSurvey H12894 junctions with its contemporary survey H12895 to the northeast and their respective nodes overlap by approximately 150 meters to 300 meters The minimum and maximum depth difference between the two surveys is -0.67 meters and 0.80 meters respectively. Of the greater than 1.2 million overlapping nodes, the average difference is -0.03 meters with a standard deviation of 0.12 meters. Ninety-five percent of the differenced surface nodes are within +/- 0.23 meters of the mean, as shown in Figure 8.NOAA Ship FERDINAND R. HASSLERNEH12895400002016Difference surface statistics for H12893 and H12894.SupportFiles\H12893_H12894_new_junc_stats.pngSurvey H12894 junctions with its contemporary survey H12893 to the southwest and their respective nodes overlap by approximately 150 meters to 500 meters The minimum and maximum depth difference between the two surveys is -0.95 meters and 0.81 meters respectively. Of the greater than 1.3 million overlapping nodes, the average difference is -0.02 meters with a standard deviation of 0.11 meters. Ninety-five percent of the differenced surface nodes are within +/- 0.22 meters of the mean, as shown in Figure 9.NOAA Ship FERDINAND R. HASSLERSWH12893400002016None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR.Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR.All equipment and survey methods were used as detailed in the DAPR.RESONSeaBat 7125MBESApplanixPOS M/V 320 V5Positioning and Attitude SystemHemisphereMBX-4Positioning SystemAML OceanographicMicroCTDSound Speed SystemODIM Brooke OceanMVP-200Sound Speed SystemRESONSVP-70Surface Sound Speed SystemSea-Bird ElectronicsSBE 19plus SeaCATConductivity, Temperature, and Depth SensorS2503.7737.7NOAA Ship FERDINAND R. HASSLERSupportFiles\Hassler_stern_bow_clean.pngNOAA Ship FERDINAND R. HASSLER (S250), shown in Figure 3, acquired all surveyed soundings during operation for H12894.Refer to the Data Acquisition and Processing Report (DAPR) for a complete description of data acquisition and processing systems, survey vessels, quality control procedures and data processing methods. Additional information to supplement sounding and survey data, and any deviations from the DAPR are discussed in the following sections.NOAA Profile V_5_4CUBEH12894_MB_2m_MLLW_parentComplete MBES29.5336.402NOAA_2mCUBEH12894_MB_2m_MLLW_FinalComplete MBES29.5336.402NOAA_2mNo Sound Speed Correction (Caris SVC processing) After SBET ApplicationBased on feedback from the Atlantic Hydrographic Branch (AHB), the Ferdinand R. Hassler discovered that one element of the recommended Caris processing workflow was not followed throughout project OPR-G309-FH-16. The Caris Sound Velocity Correction (SVC) process was conducted before but not after loading Smoothed Best Estimates of Trajectory (SBETs). It is recommended to perform the SVC process after loading SBETs in order for the ray tracing to account for the updated motion and attitude information. A copy of survey H12932 was re-processed to assess the effect of not applying SVC after loading SBETs. As viewed in Caris Subset Editor, the vertical difference between processing methods ranged from 0.005 - 0.010 meters in all sampled areas, including two wrecks. The SVC processing methods were also compared using 2 meter and 4 meter difference surfaces. In the 2 meter difference surface, the depths differ by -8.17 to 3.07 meters, with a mean difference of 0.00 meters and a standard deviation of 0.00 meters, and 95% of nodes exhibit a depth difference of ±0.01 meters. In the 4 meter difference surface, the depths differ by -0.74 to 0.62 meters, with a mean difference of 0.00 meters and a standard deviation of 0.00 meters, and 95% of nodes exhibit a depth difference of ±0.01 meters. The high values in the difference surfaces are isolated and limited to features and steep slopes. A detailed review confirmed that the high values in the difference surfaces are entirely the result of CUBE gridding inconsistencies and small horizontal shifts in the grid node structure rather than actual vertical differences in the sounding data. The results of this testing were discussed with HSD Operations and AHB. Based on the limited magnitude of the error, it was concluded that re-processing the entire project was unnecessary. The ship’s Caris processing SOP has been updated to reflect the recommended SVC workflow. Please refer to the DAPR and the correspondence in Appendix II for more information. Delayed HeaveEight (8) total lines from the port and starboard bathymetry data did not have delayed heave applied. These lines are: PORT DN 215 Line #2016__2150524.HSX (2) PORT DN 217 Line #2016_2170958.HSX PORT DN 222 Line #2016_2221111.HSX PORT DN 228 Line #2016_2282120.HSX STBD DN 215 Line #2016__2152214.HSX (2) STBD DN 217 Line #2016__2170958.HSX STBD DN 222 Line #2016_2221111.HSX STBD DN 228 Line #2016_2282120.HSX There is higher uncertainty associated with these lines, however all are still within allowable total vertical uncertainty tolerances and meet the standards as set forth in the 2016 HSSD.Data density of the H12894 2-meter finalized surface.SupportFiles\H12894_MB_2m_MLLW_Final.QAv2.density.pngData DensityA density analysis was run to calculate the number of soundings per surface node. The results determined that greater than 99.5% of all nodes contained five (5) or more soundings which meets the data density specifications (See Figure 13).Total vertical uncertainty analysis for the 2-meter finalized surface.SupportFiles\H12894_MB_2m_MLLW_Final.QAv2.tvu_qc.pngNodes exceeding allowable total vertical uncertainty. Two hundred six (206) exist with sheet limits.SupportFiles\H12894_TVU_Final_Exceeded.pngCARIS subset highligting area flagged as exceeding TVU tolerance at position 33-07-01.119 N and 078-10-46.598 W.SupportFiles\H12894_TVU_Exceeded_example.pngTotal Vertical Uncertainty AnalysisPydro's Finalized CSAR QA tool was used to calculate the percentage of nodes which meet total vertical uncertainty (TVU) specifications. The resulting statistical analysis yielded greater than 99.5% of all nodes meet TVU specifications (See Figures 14). In addition, a custom layer was created for the finalized surface submitted in correlation with H12894. The layer was derived from the difference between the calculated uncertainties of individual nodes and the allowable uncertainty at the coupled node and scaled to a 95% confidence interval. Two hundred six (206) nodes within the sheet limits were found to exceed alllowable TVU tolerances (See Figure 15). Each of these nodes were reviewed and in most cases exist in areas of seafloor with highly varying vertical relief. Flagged nodes also exist in locations exhibiting higher standard deviation due to aberrant data that were not rejected from the dataset or where overlapping lines are vertically offset due to minor tidal and/or refraction related errors. In these areas, the finalized 2m grid does not honor the extraneous soundings beyond allowable vertical uncertainty tolerances for the given depth. See Figure 16 for an example. Designated SoundingsWithin the limits of H12894, one (1) sounding is flagged as designated. All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.No platforms exist for this survey.No Aids to navigation (ATONs) exist for this survey.No Significant Features exist for this survey.Prior survey comparisons exist for this survey, but were not investigated.No new insets are recommended for this area.No new surveys or further investigations are recommended for this area.Shoreline was not assigned in the Hydrographic Survey Project Instructions or Statement of Work.No overhead features exist for this survey.No present or planned construction or dredging exist within the survey limits.No ferry routes or terminals exist for this survey.No submarine features exist for this survey.No shoals or potentially hazardous features exist for this survey.No channels exist for this survey. There are no designated anchorages, precautionary areas, safety fairways, traffic separation schemes, pilot boarding areas, or channel and range lines within the survey limits.One (1) new uncharted wreck was identified with a least depth greater than 20 m. Although not considered a danger to surface navigation, it is recommended this feature be considered for charting. See the associated final feature file for more information.The hydrographer has compared a sounding plot from the surveyed area to the charted soundings. Additionally, a Chart Comparison Tool contained in the HCellScan utiliy under PydroExplorer was run to compare the most recent large scale ENC (US3SC10M) to processed sounding data and the S-57 Final Feature File. There are no charted contours to compare.No Danger to Navigation Reports were submitted for this survey.Two charted wrecks with "Rep" depths were investigated at 33-08-58.233 N and 078-16-20.033 W and 33-08-28.757 and 078-15-00.310 W respectively. Complete coverage multibeam disproved these features and it is recommended both be removed from the chart.No Maritime Boundary Points were assigned for this survey.Chart 11520 comparison. Soundings flagged in red are generally 1 fathom shoaler than the closest charted sounding.SupportFiles\H21894_HCell_Chart_Comparison_results.pngZoom showing minor shoaling in the region of 33-06-39.288 N and 078-16-43.175 W. Soundings flagged in red are approximately 1 to 2 m shoaler than currently charted nearby soundings.SupportFiles\H12894_shoaling_zoom_west_side.pngA comparison was performed with Chart 11520 (1:432,720) using soundings derived from the 2-meter parent surface, shown in Figure 17. Charted depths generally agree within 1 fathom of H12894 surveyed soundings. An area of shoaling at approximately 33-06-39.288 N and 078-16-43-175 W shows a cluster of 16 fathom soundings between a charted 17 and 18 fathom sounding. See Figure 18. 2016-09-27453772016-10-082013-0943272011520ENC US3SC10M objects and soundings from within the survey bounds of H12894 were ungrouped in CARIS BASE Editor. Using the QC Tools Chart Comparison function these were then compared to a survey scale sounding set extracted from H12894 with a radius value of 1mm at a 1:200,000 scale. Similar to the visual comparison made for RNC 11520, results showed that minor shoaling of 1-2 fathoms exists. See Figure 17 and 18 above.false21US3SC10M2014-09-152016-10-06432720Four (4) bottom samples were acquired for this survey. Two (2) additional bottom samples were attempted but no sample was recovered. Per Section 7.5 of the 2016 HSSD these have been included in the final feature file with NATSUR (nature of surface) attribution of "unknown." See final feature file for more information.