OPR-B396-NRT5BH2-16Hudson RiverHudson RiverNavigation Response Team 5 and Bay Hydro IIH128732Kingston to CatskillNew YorkUnited States50002016LTJG Sarah L ChappelNavigable Area2016-04-132016-07-212016-08-31Multibeam Echo SoundermetersUniversal Transverse Mercator (UTM)UTCPacific Hydrographic BranchThe purpose of this survey is to provide contemporary surveys to update National Ocean Service (NOS) nautical charts. All separates are filed with the hydrographic data. Any revisions to the Descriptive Report (DR) generated during office processing are shown in bold red italic text. The processing branch maintains the DR as a field unit product, therefore, all information and recommendations within the body of the DR are considered preliminary unless otherwise noted. The final disposition of surveyed features is represented in the OCS nautical chart update products. All pertinent records for this survey, including the DR, are archived at the National Centers for Environmental Information (NCEI) and can be retrieved via http:// www.ncei.noaa.gov/.NOAAThe survey area is located in the central portion of the Hudson River between Catskill, NY and Kingston, NY. An overview of the geographic location of H12873 is shown in Figure 1. Due to the river's orientation, the Northeast and Southwest corners of the survey were used for survey limits opposite of the Northwest and Southeast as stated in Table 1. 42.235697222273.841958333341.929605555673.9620444444H12873 survey limits on Hudson River, overlaid on Chart 12347.file:///M:/OPRB396NRT5BH216/Surveys/H12873/Compilation/Report/Office/Images/H12873_Survey%20Limits.pngSurvey was located on a river that ran Northeast to Southwest, as reflected on the survey limits Lat. and Long.SLCSurvey limits were acquired in accordance with the requirements in the Project Instructions and the HSSD.The intent of this survey is to supersede all bathymetry, seafloor features, and bottom characteristics within the assigned survey area as defined by these instructions for updating of NOAA Chart 12347. This project covers approximately eight SNM of critical survey area as designated in NOAA Hydrographic Survey Priorities. The entire survey is adequate to supersede previous data.Data acquired in H12873 meet multibeam echo sounder (MBES) coverage requirements for object detection, including the five soundings per node data density requirements in section 5.2.2.2 of the Hydrographic Surveys Specifications and Deliverables (HSSD). In order to extract descriptive statistics of the data density achievements, the finalized surface is queried with CARIS and examined in Excel (Figure 2). Overall, the required data density was achieved in 99.6% of the nodes.Summary table showing the percentage of nodes satisfying the five sounding density requirements for H12873. file:///M:/OPRB396NRT5BH216/Surveys/H12873/Compilation/Report/Office/Images/H12873_Data_Density.pngThe difference between the passing nodes in QC tools and total nodes is 159,509. Total node count on the finalized surface from Caris Compute Statistics is 76,180,631, which is 99.8 passing. All waters in survey areaObject Detection Coverage accomplished using either: A) Object detection MBES, or B) 200% SSS coverage with concurrent set line spacing SBES or MBES. Refer to HSSD Section 5.2.2.1Survey coverage was in accordance with the requirements in the Project Instructions and the HSSD with the exception of a few holidays present as a result of acoustic shadowing within the limits provide by HSD, sheet limit holidays that are covered by the junction survey F00658, and true line spacing holidays. A GPS dropout holiday was identified (Figure 3) where the survey line was offset from the seafloor approximately 1.5 meters. When removed from the surface, a line of small holidays appeared. All cases were investigated to ensure there is no threat of an obstruction.Images of GPS holiday in trackline and surface overlaid to chart (left) and subset editor (right). Grey point cloud indicates soundings rejected by hydrographer due to 1.5m offset from surrounding data.\Images\GPS holiday.pngGeneral location of H12873 overlaid on satellite imagery, subset star indicates approximate location of Kingston, NY.\Images\H12873_Google_Earth_Overlay.pngS54010362.9000004.20S30020223.80000037.100586.70000041.307.000005.552016-07-212016-07-252016-07-262016-07-272016-07-282016-08-022016-08-032016-08-042016-08-052016-08-082016-08-092016-08-102016-08-112016-08-162016-08-172016-08-182016-08-192016-08-31Refer to each vessel 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.S540117.31.8S30029.1440.5All data for survey H12873 was acquired by NOAA R/V Bay Hydro II and NRT Survey Launch 5. The vessels acquired multibeam depth soundings, backscatter data, and sound speed profiles.KongsbergEM 2040MBESApplanixPOS MV5Positioning and Attitude SystemSonTekCastAwayConductivity, Temperature, and Depth SensorKongsbergEM 3002MBESSeabird SBE19+Conductivity, Temperature, and Depth SensorValportMini SVSSound Speed SystemOdomDigibar ProSound Speed SystemMultibeam crosslines were acquired using BHII and NRT5. Crosslines were collected, processed, and compared in accordance with Section 5.2.4.3 of the HSSD. Crossline totals were 41.3 LNM and 7.03% of mainscheme coverage; this coverage exceeds the 4.0% requirement for object detection MBES. A 50cm CUBE surface was created using only mainscheme lines and a second 50cm surface was created using only crosslines. Using the two surfaces, a difference surface (mainscheme - crosslines = difference surface) was generated at a 50cm resolution. Statistics show the mean difference between the depths derived from the mainscheme and crosslines was 0.07 meters (crosslines being deeper) with a standard deviation of 0.08 meters (Figure 5). The difference surface was also compared to the IHO allowable total vertical uncertainty (TVU) standards. In total, 99.9% of the depth differences between H12873 mainscheme and crossline data met HSSD TVU standards (Figure 6).Crossline comparison with mainscheme lines.\Images\H12873_Crossline_comparison.pngSummary table indicating percentage of difference surface nodes between H12873 mainscheme and crossline data that met HSSD allowable TVU standards.\Images\H12873_Crossline_IHOness.pngThe reviewer calculated the crossline percentage to be 7.8%0.05385ERS via VDATUMS54010.5N/A0.2S30020.5N/A0.2Total Propagated Uncertainty (TPU) values for H12873 were derived from a combination of fixed values for equipment and vessel characteristics, as well as field assigned values for sound speed uncertainties. In addition to the usual a priori estimates of uncertainty, some real time and post processed uncertainty sources were also incorporated into the depth estimates of the survey. Real-time uncertainties from the Kongsberg MBES sonars were incorporated and applied during post processing. Uncertainties associated with vessel roll, pitch, gyro, and navigation were applied real-time, because H12873 used a real-time kinematic (RTK) positioning service. The recorded delayed heave Applanix files included an estimate of the heave uncertainty and were applied during post-processing. All of the aforementioned uncertainties were applied in CARIS. As stated, H12873 is an ellipsoidally referenced survey (ERS) and the tidal component was accomplished with a separation model. Additional information about RTK and the separation model is located in section C.1 and C.2 of this document. Uncertainty values of the submitted finalized surface were calculated in CARIS using the "Greater of the Two" of uncertainty and standard deviation (scaled to 95%). To visualize the locations in which accuracy requirements were not met for the finalized surface, a custom predicted NOAA compliance layer was created. The layer is based on the difference between calculated uncertainty of the nodes and the allowable NOAA uncertainty. To quantify the extent to which accuracy requirements were met, the predicted NOAA compliance layer was queried with CARIS and examined in Excel (Figure 7). Overall, 100% of the nodes met HSSD uncertainty requirements.Summary table shows the percentage of nodes that satisfy the NOAA accuracy level.\Images\H12873_Uncertainty_IHOness_table.png QC Tools reported 76,172,984 passing. Total node count on the finalized surface from Caris Compute Statistics is 76,180,631.One junction comparison was completed for H12873. A 50cm surface was created from H12873 survey data to match the junction surface provided with the Project Instructions. A depth comparison was performed using the CARIS difference surface and CARIS compute statistics tool.F0065850002015Navigation Response Team 5NF00658 was a response survey conducted in 2015 that surveyed multiple small areas of the Hudson River. Due to the nature of the response survey, H12873 junctions with F00657 multiple times. Approximately 0.205 square nautical miles of overlap coverage was achieved. A difference surface between the 50cm resolution H12873 surface and the 50cm resolution F00658 surface show a strong depth agreement. The difference range is -2.18 to 1.7 meters with a mean of 0.06 meters (F00658 being deeper) and a standard deviation of 0.15 meters (Figure 8). The greatest difference in depths are in the Hudson River's deeper sections where large sand waves are present. Due to the influence of currents and tides, the sand waves migrate and transform over time. These changes are clearly visible in the difference surface (Figure 9). However, in less dynamic sections, the difference surface shows good agreement between the two surveys.Difference surface statistics between H12873 and F00658.\Images\H12873_Junction stats_F00658.pngDifference surface between H12873 (navy) and junction survey F00658 (peach) overlaid onto Chart 12347. Area shows good agreement on edges, and differences where sand waves are present.\Images\H12873_Junction image_F00658.pngH1287450002016Navigation Response Team 5SJunction analysis will be completed at the Pacific Hydrographic Branch.Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR.Cellular network dropoutsThe RTK corrections were acquired with the use of an NTRIP caster (Networked Transport of RTCM via Internet Protocol) which required continuous, stable Internet connection to receive the RTK corrections. The survey teams had a 4G LTE wireless hotspot, but there were specific occasions during survey operations that wireless Internet connectivity was limited, which inhibited RTK corrections to be imported. The dropouts resulted in survey line depths that were significantly different from surrounding data (Figure 10). If the dropout was recognized during acquisition, acquisition on the line ended and the data was reacquired once the signal returned. When the anomaly was identified during processing, data was rejected and a new line was later acquired to ensure object detection MBES coverage was achieved. Three images of sections of the same line (A, B, and C) with data colored by lines. The gold data shows when RTK connections were compromised and "drifted" from the true bottom.\Images\RTK_drift_1.pngNone ExistThere were no other factors that affected corrections to soundings.Surface sound speed was collected real-time and integrated into the bathymetric data for both the Kongsberg EM2040 on Bay Hydro II and the Kongsberg EM3002 on NRT5.Sound speed casts were acquired via CTD with a SonTek CastAway on Bay Hydro II and a Sea-Bird SBE19+ on NRT5. Casts were collected at the beginning, during, and end of the survey day to ensure accurate representation for the survey area. Cast frequency was increased if survey area was large or sectioned. These methods resulted in a cast every three to four hours as outlined in the HSSD. The distribution of sound speed casts are shown below (Figure 11). Casts were applied using the "nearest in distance with time" within three hours. The hydrographer found this method to more accurately represent the sound speed within the survey limits of H12873.Sound speed profiles (red) acquired for H12783 (navy blue) overlaid onto Chart 12347.\Images\H12873_sound speed profiles.pngAll equipment and survey methods were used as detailed in the DAPR, with the addition of RTK corrections for positional data. All data reduction procedures conform to those detailed in the DAPR.The adjustment is located in the HVF associated with this project.GPS Antenna lever arm to reference point.2016-06-30Field unit measurements showed an incorrect offset from previous years.Raw Backscatter was logged in the .all file and has been sent to the Processing Branch. Backscatter was not processed by the field unit.NOAA Profile V_5_4H12873_MB_50cm_HDRCUBE0.500.0921.72NOAA_0.5mObject DetectionH12873_MB_50cm_HDR_FinalCUBE0.500.1121.72NOAA_0.5mObject DetectionThe surfaces were reviewed where noisy data, or 'fliers'', were incorporated into the gridded solution, causing the surface to be shoaler than the true seafloor. Where these erroneous soundings cause the gridded surface to be shoaler than the reliably measured seabed by greater than maximum allowable vertical uncertainty at that depth, the noise was rejected and the surface recomputed.The minimum depth on the parent surface should be 0.11. The datum on both surfaces should be HRD for Hudson River Datum, not HDR. The finalized surface was submitted with '_updated' at the end of the filename.Bay Hydro II POS MV5There were several instances during survey operations that Bay Hydro II experienced discrepancies in the POS accuracy, which halted data acquisition. The anomaly was related to an aging cable connecting the IMU and the POS topside unit. The image below, taken when the vessel was not moving, shows the significant drift in altitude, as well as incorrect speed and heading readings (Figure 12). The immediate remediation was to discontinue logging the POS file, reboot the system, then continue to survey on a new POS file. This temporary work-around reduced efficiency but allowed for continued survey operations. Because of these findings, the field party used RTK positioning data for this project, and the available post processed data (SBETs) as a QC tool.Screen grab of POS data when anomaly occurred. Red boxes outline the incorrect values\Images\H12873_POS drift.png RTK was used for vertical control and the real time solution was written directly to the POSPac file. In CARIS, a GPS tide was applied in reference to the ellipsoid. A VDatum separation model was applied to reduce the data to HRD. The associated RTK memo is located in Appendix II.Ellipsoidally Referenced SurveyERS via VDATUMOPR-B396-NRT5BH2-16_HDR (1).csarThe separation file was provided to the field party from the project manager. This survey is referenced to the Hudson River Datum, as stated on RNC 12347. The Hudson River, has large fluctuations in water levels due to hydrological, meteorological, and other non-tidal influences that make tidal datums less representative of the average lower water conditions. A fixed low water reference plan, Hudson River Datum (HRD), adopts the chart datum for certain portions of the Hudson River to approximate mean low water when river levels are lowest. The full Hudson River Datum report is included under Appendix II of this document.North American Datum of 1983 (NAD83)18NHorizontal control used Real Time Kinematic (RTK) corrections using CORS stations maintained by New York Department of Transpiration (NYDOT) as part of the New York State Spatial Reference Network (NYSNet). Horizontal network datum for NYSNet correctors is NAD83 (CORS96). Additional information regarding the NYSnet system can be found at http://cors.dot.ny.gov/spiderweb/frmIndex.aspx. In order to use the NYSnet correctors, a stable Internet connection and computer software are needed to receive the CORS corrections. The field unit used NTRIP (Network Transport of RTCM data over IP) which is a protocol for transmitting RTK correction data from the base station to the rover (survey vessel) using the Internet. Both NRT5 and Bay Hydro II were equipped with a Sierra Wireless cellular Internet Wi-Fi modem that provides steady, always-on Internet connectivity to its computers. Lefebure (NTRIP) software configured on an acquisition laptop to receive the correction data was transmitted to the POS MV5 via serial cable. During survey acquisition, the Lefebure window shows the status of the incoming data stream. This was monitored to ensure continuous reception of RTK. In addition, confirmation was attained when vertical and horizontal accuracies of the POS MV5 were less than 5cm.Hudson Falls, NY (324 kHz)Chart comparisons were conducted for RNC Chart 12347 and ENC US5NY43M using a Caris CUBE surface and selected soundings. The soundings and contours were visually inspected to identify any discrepancies. Overall, comparisons between H12873, Chart 12347 and U5NY43M showed good agreement with the exception of a few egregious areas. H12873 sounding data was approximately two feet shoaler than charted soundings in the majority of the surveyed area. The following sections highlight several examples of significant differences identified between H12873 data and charted soundings and contours. 12347222340000312010-072016-09-132016-08-27Areas around Kingston Point Reach show significant movement of the charted 18ft contour, as well as H12873 sounding data 2ft-7ft shoaler than charted soundings (Figure 13). H12873 data in the east (alternate) channel near the Kingston-Rhinecliff Bridge shows significant movement of the charted 18ft contour, as well as sounding data up to 19ft shoaler than charted soundings (Figure 14). The channel to the east of Barrytown Reach, west of Barrytown shows significant shoaling (up to 19ft) from charted soundings (Figure 15). The Red "94" buoy north of Esopus Creek marks the outside of the main channel, but does not accurately mark the <20ft shoal area that extends from Green Flats downriver. (Figure 16). H12873 soundings (blue and violet) and 18ft contour (green), compared with soundings and 18ft contour from Chart 12347 (black). Pink overlay depicts H12873 survey coverage. \Images\H12873_chart comparison 1.pngH12873 soundings (blue and violet) and 18ft contour (green), compared with soundings and 18ft contour from Chart 12347 (black). Red hexagons indicate areas of survey data up to 19ft shoaler than charted soundings. Pink overlay depicts H12873 survey coverage. \Images\H12873_chart comparison 2.pngH12873 soundings (blue and violet) and 18ft contour (green), compared with soundings and 18ft contour from Chart 12347 (black). Red hexagons indicate areas of survey data up to 19ft shoaler than charted soundings. Pink overlay depicts H12873 survey coverage.\Images\H12873_east Barrytown.pngH12873 soundings (blue and violet) and 18ft contour (green), compared with soundings and 18ft contour from Chart 12347 (black). Red square and hexagon indicate extension of charted shoal area. Pink overlay depicts H12873 survey coverage.\Images\H12873_chart comparison 3.pngUS5NY43M40000142016-12-142016-12-19falseThe sounding selection comparison has the same results as raster Chart 12347.No Maritime Boundary Points were assigned for this survey.In total, H12873 had four areas/features with a label containing PA, ED, PD, or Rep. A portion of the river between Barrytown Reach and Barrytown contained three "Rep" charted features (Figure 17). The "Rep (2004)" shoal area northwest of Esopus Creek is proven in MBES data (Figure 16).Charted "Rep" features around Barrytown. H12873 soundings (blue and violet) and 18ft contour (green), compared with soundings and 18ft contour from Chart 12347 (black). Pink overlay depicts H12873 survey coverage.\Images\H12873_charted shoals 1.png All survey features are referenced and attributed in the digital data of the submitted Final Feature File.No Danger to Navigation Reports were submitted for this survey.In reference to Chart 12347, four shoaling areas were reported within the H12873 survey boundary. These shoaling areas areas were investigated with MBES coverage up to the 12 ft. contour as required in the Project Instructions (Figures 16 & 17).The Hudson River maintained channel was not assigned as part of sheet H12873, however, some channel investigation occurred during acquisition, specifically Kingston Reach (Figure 18), Tivoli Reach (Figure 19), Barrytown Reach (Figure 20), and Malden-on-Hudson Reach (Figure 21). In these sections, the channel tabulated depths were shoaler than H12873 data.H12873 coverage (pink) and soundings (blue) in Kingston Point Reach overlaid on Chart 12347.\Images\H12873_channels_2.pngH12873 coverage (pink) and soundings (blue) in Tivoli Reach overlaid on Chart 12347.\Images\H12873_channels_1.pngH12873 coverage (pink) and soundings (blue) in Barrytown Reach overlaid on Chart 12347.\Images\H12873_channels_Barrytown.pngH12873 coverage (pink) and soundings (blue) Malden-on-Hudson overlaid on Chart 12347.\Images\H12873_channels_Malden.pngNo bottom samples were required for this survey.Shoreline was not assigned in the Hydrographic Survey Project Instructions or Statement of Work.Limited shoreline investigation was assigned in the Project Instructions.No prior survey comparisons exist for this survey.Aids to navigation (ATONs) exist for this survey, but were not investigated.Overhead features exist for this survey, but were not investigated.No submarine features exist for this survey.No ferry routes or terminals exist for this survey.No platforms exist for this survey.No Significant Features exist for this survey.No present or planned construction or dredging exist within the survey limits.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, 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.LTJG Sarah L. ChappelChief of Party2017-02-02