S-N912-FA-16 Deception PassF00682WashingtonStrait of Juan De FucaDeception Pass10000Reson 7125North American Datum 1983Mean Lower Low WaterERZTUTM Zone 10NNOAA Ship FAIRWEATHER2016-11-212016-11-21CDR Mark Van Waes, NOAA2017-02-17This hydrographic survey was acquired in accordance with the requirements defined in the 2016 NOS Hydrographic Survey Specifications and Deliverables Manual (HSSD) Section 5.2.2.3 Complete Coverage Multibeam survey. All requirements set forth in the NOAA Field Procedures Manual for Hydrographic Surveying (FPM) dated May 2014 and Hydrographic Survey Technical Directives (HTD) 2016-1 were met.48.4078888889122.64808333348.4048055556122.635111111Figure 1: F00682 Survey overviewSupportFiles\F00682_Overview_Rainbow.PNGNOAA’s Center for Operational Oceanographic Products and Services (CO-OPS) requested updated bathymetric survey data in Deception Pass, WA. The survey data will help define a site acceptable for the deployment of a bottom mounted current meter station. In addition to the CO-OPS request, there have been several other inquires to update the nautical chart for recreational boaters. Survey data from this project is intended to supersede all prior survey data in the common area.The entire survey is adequate to supersede previous data.In order to support the NOS and CO-OPS missions, new current meter stations are regularly required. The best method for assembling the information needed to deploy these stations is survey. The primary objective of the survey is to provide information to determine the best location for current meter installation. It is necessary to obtain the longitude, latitude, bottom type, depth, salinity, and observe any coastal hazards/obstructions around the sites. The NOAA CUBE parameters defined in the HSSD were used for the creation of all CUBE surfaces in Survey F00682. The surfaces have been reviewed where noisy data, or "fliers," are incorporated into the gridded solutions causing the surfaces to be shoaler or deeper than the true sea floor. Where these spurious soundings cause the gridded surface to be shoaler or deeper than the reliably measured seabed by greater than the maximum allowable Total Vertical Uncertainty at that depth, the noisy data have been rejected by the Hydrographer and the surface recomputed. Flier Finder v3, part of the QC Tools package within Pydro, was used to assist the search for spurious soundings following the gross cleaning. Flier Finder was run multiple times for each surface, reducing the flier height value for each consecutive run. This allowed Flier Finder to accurately and quickly identify gross fliers, but as the flier height was reduced the effectiveness of the tool diminished. At this point, the hydrographer ceased using the tool and returned to manual cleaning.Please reference Data Acquisition and Processing Report S-N912-FA-16_Deception_Pass_DAPR for a complete description of data acquisition and processing systems, survey vessels, quality control procedures and data processing methods.To verify that all data meet the accuracy specifications as stated in the HSSD, a child layer titled "NOAA_Allowable_1" was created for the 1 and 2 meter finalized surfaces using the equation stated in Section C.2.1 of the DAPR. These surfaces were then analyzed using the Pydro Finalized CSAR QA tool. Figure 2 shows an overview of the NOAA Allowable Uncertainty layers in each of the surfaces. Figure 3 shows the statistics for each of the individual surfaces. It was found that at least 99.67% of nodes in the 1 and 2 meter grids meet or exceed NOAA Allowable Uncertainty specifications for all depths of survey F00682. For individual graphs per surface of uncertainty and density requirements, see the Standards Compliance Review in Appendix II. Finalized surfaces were analyzed using the Pydro QC Tools Grid QA feature and the results are shown below in Figure 4. Density requirements for F00682 were achieved with at least 97.99% of finalized surface nodes containing five or more soundings as required by HSSD Section 5.2.2.3. The few nodes that did not meet density requirements are due to sparse data in the outer beams, especially near steep slopes and rocky areas where acoustic shadowing occurred, and at the edges of the survey limits as shown in Figure 4. For individual graphs (per surface) of density requirements, see the Standards and Compliance Review located in Appendix II. Figure 2: F00682 NOAA Allowable Uncertainty overview.SupportFiles\F00682_NOAA_Allowable.pngFigure 3: F00682 NOAA Allowable Uncertainty statistics.SupportFiles\F00682_NOAAness.PNGFigure 4: F00682 Density overview.SupportFiles\F00682_Density.PNGFigure 5: F00682 Density statistics.SupportFiles\F00682_Density_Stats.PNG The "NOAA_Allowable_1" layers were created using the equation stated in Section B.2.1.1 of the DAPR18427168025000242013-052016-06-282016-07-09US5WA31M25000232016-06-152016-06-15falseA comparison was performed between survey F00682 and Chart 18427 as well as ENC US5WA31M using CARIS HIPS and SIPS sounding layers derived from a 4 meter surface. The soundings were overlaid on the charts to assess differences between the surveyed soundings and the charted depths. All data from F00682 should supersede charted data. In general, surveyed soundings agree within 1 fathom of the majority of charted depths. A full discussion of the disagreements follows below. The charted depths of Chart 18427 are identical to those found on ENC US5WA31M and are in general agreement with soundings from F00682, with most depths agreeing within 3 fathoms as shown in Figure 6. Contours from F00682 are in general agreement with charted contours, with the exception of of the shoreline contours as shown in Figures 8 and 9. Additionally, charted shoreline to the north and south of Deception Pass is not in agreement with surveyed soundings, as shown in Figure 16. The overlap in these areas appears to be largely due to chart scale. To more accurately visualize trends within these differences, a 4 meter TIN surface was interpolated from the ENC sounding layer. A corresponding 4 meter surface from F00682 was created and differenced from the 4 meter TIN surface. This difference surface showed the mean difference between surfaces to be 3.86 fathoms with 95% of nodes falling within 7.73 fathoms, as shown in Figure 10. Figure 9 shows this difference surface where red colors indicate F00682 was shoaler than the ENC US5WA31M, green colors indicate agreement, and blue colors indicate F00682 was deeper than ENC US5WA31M. The majority of F00682 is either in agreement with or is deeper than charted depths, with the exception of near shore areas where F00682 is shoaler.Figure 6: Comparison of F00682 soundings as compared to Chart 18427 depthsSupportFiles\F00682_Soundings.PNGFigure 7: Comparison of F00682 contours as compared to Chart 18427 depthsSupportFiles\F00682_East_Contour_Comparison.pngFigure 8: Comparison of F00682 contours as compared to Chart 18427 depthsSupportFiles\F00682_West_Contour_Comparison.pngFigure 9: Comparison of F00682 soundings as compared to ENC US5WA31M depthsSupportFiles\F00682_ENC_Difference_Legend.PNGFigure 10: Statistical comparison of F00682 soundings as compared to ENC US5WA31M depthsSupportFiles\F00682_ENC_Difference.PNGF00682_MB_1m_MLLWCUBE1NOAA_1mComplete MBESF00682_MB_2m_MLLWCUBE2NOAA_2mComplete MBESF00682_MB_1m_MLLW_FinalCUBE1030NOAA_1mComplete MBESF00682_MB_2m_MLLW_FinalCUBE21860NOAA_2mComplete MBESVDatumPort Townsend9444900Friday Harbor9449880The vertical datum for this project is Mean Lower Low Water. While a TCARI grid was used to initially reduce the soundings to MLLW, following successful processing of SBETS VDatum was used to reduce soundings to MLLW.See attached Tide Note dated December 12, 2016Whidbey Island, WA - 302 kHz (100 BPS)During real-time acquisition 2805 and 2806 received correctors from USCG DGPS for increased accuracies.Due to the relatively small size of the survey crosslines were not acquired to satisfy quality control requirements in Section 5.2.4.3 of the HSSD. Instead, the two survey launches used different sonar frequencies (FA2805 used 200kHz and FA2806 used 400kHz) both acquiring MB data for the entire survey area, effectively satisfying HSSD quality control requirements. To evaluate coverage, a 1-meter CUBE surface was created using strictly lines collected by FA2805, and a 1-meter CUBE surface was created using strictly lines collected by FA2806. From these two surfaces, a difference surface (FA2805 mainscheme - FA2806 mainscheme = difference surface) was generated at a 1-meter resolution (Figure 11), and is submitted in the Separates II Digital Data folder. Statistics show the mean difference between the depths derived from FA2805 and FA2806 was -0.08 meters (with FA2805 being deeper) with 95% of nodes falling within +/- 0.52 meters (Figure 12). For the respective depths, the difference surface was compared to the allowable NOAA accuracy standards (Figure 13). In total, 96.86% of the depth differences between FA2805 and FA2806 data were within allowable NOAA uncertainties (Figure 14). Although depth differences between the surfaces created from FA2805 and FA2806 exist (Figure 11), the individual soundings from FA2805 and FA2806 are in agreement as shown in Figure 15. The observed differences are largely caused by the griding algorithm's representation of the two separate data sets. This is especially apparent along steep slopes, where small changes in density and position resulted in significant changes in the resulting launch-specific grid. An original final feature file was not provided for this survey, and no features were assigned. An incorrectly charted islet was disproved during acquisition, a final feature file was created and included with the data submission, as seen in Figure 17. In order to prevent visual data gaps between the finalized surfaces, a waiver was obtained to modify the finalized surface depth ranges. The 1 and 2 meter surface depths were extended by 10 times their respective resolution for greater overlap as shown in Section F of this report. As a result of modifying the depth ranges, the 2 meter finalized surface covered the extents of the 4 meter surface. As the 2 meter surface met all density and NOAA uncertainty requirements for the expanded range, the requirement to submit the 4 meter surface was waived.Figure 11: F00682 comparison between FA2806 and FA2805 coverageSupportFiles\F00682_FA2806_FA2805_Difference_Legend.PNGFigure 12: F00682 FA2806 and FA2805 comparison statisticsSupportFiles\F00682_1m_Diff.pngFigure 13: F00682 difference surface compared to NOAA accuracy standardsSupportFiles\F00682_FA2806_FA2805_Overview_NOAAness.PNGFigure 14: F00682 Magnitude of survey launch differenceSupportFiles\F00682_FA2806_FA2805_NOAAness.PNGFigure 15: F00682 point cloud agreement between launchesSupportFiles\F00682_FA2805_FA2806_Soundings.pngFigure 16: F00682 example of multibeam data overlapping charted shorelineSupportFiles\F00682_MB_Shoreline_Overlap_Highlights.pngFigure 17: F00682 incorrectly charted islet in Deception PassSupportFiles\F00682_LNDARE_Arrow.pngSee attached correspondence regarding depth ranges on submitted finalized surfaces.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 Summary, and all accompanying records and data are approved. All records are forwarded for final review and processing to the Processing Branch.The survey data meet or exceed requirements as set forth in the NOS Hydrographic Surveys Specifications and Deliverables, Field Procedures Manual, Letter Instructions, and all HSD Technical Directives, except as noted in this Descriptive Report Summary. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required unless otherwise noted herein.CDR Mark Van Waes, NOAAChief of Party2017-02-28LT Bart Buesseler, NOAAField Operations Officer2017-02-28LT Damian Manda, NOAAFourth Officer2017-02-28HCST Douglas BravoHydrographic Chief Survey Technician2017-02-28ENS Matthew Sharr, NOAASheet Manager2017-02-28