S-E903-BH2-21 Patuxent River Patuxent River, MD NOAA NRT-BHII H13518 1 Town Point to Hog Point Maryland United States 5000 2021 LTJG Kevin Tennyson Navigable Area 2021-05-14 2021-06-25 2021-12-06 Multibeam Echo Sounder meters UTC Pacific Hydrographic Branch Any revisions to the Descriptive Report (DR) applied during office processing are shown in red italic text. The DR is maintained as a field unit product, therefore all information and recommendations within this report are considered preliminary unless otherwise noted. The final disposition of survey data is represented in the NOAA nautical chart products. All pertinent records for this survey are archived at the National Centers for Environmental Information (NCEI) and can be retrieved via https://www.ncei.noaa.gov/. Products created during office processing were generated in NAD83 UTM 18N, MLLW. All references to other horizontal or vertical datums in this report are applicable to the processed hydrographic data provided by the field unit. CC0-1.0 (NOAA Field Units) CC0-1.0 https://creativecommons.org/publicdomain/zero/1.0/ https://creativecommons.org/publicdomain/zero/1.0/legalcode These data were produced by NOAA and are in the public domain within the United States. NOAA waives any potential copyright and related rights in these data worldwide through the Creative Commons Zero 1.0 Universal Public Domain Dedication (CC0). NOAA The survey area is located in the Patuxent River with the sub locality between Town Point and Hog Point, just offshore of Solomons Island, Maryland. 38.32903055555556 76.63765000000001 38.309441666666665 76.3923888888889 H13518 Surveyed Area file:///D:/H13518/01_HDR/Images/Multimedia/H13518_Surveyed_Area.PNG Data were acquired to the survey limits in accordance with the requirements in the Project Instructions (PIs) and the April 2021 NOS Hydrographic Surveys Specifications and Deliverables (HSSD). Sheet limits were not met anywhere along the edge of a landmass due to shallow water depths and the safe maneuverability of the vessel; nor were they met along the charted shoal, 500 meters east of Solomons Island for the same reasons. This area of the Southern Patuxent River needed a contemporary hydrographic survey to update the nautical charts. 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. Data acquired in H13518 meet multibeam echo sounder (MBES) coverage requirements for object detection, as required by the HSSD unless otherwise stated in this report. This includes crosslines (see Section B.2.1 of this document), NOAA allowable uncertainty (see Section B.2.2 of this document), and density requirements (see Section B.2.12 of this document). Additional compliance statistics can be found in the Digital Data folder located in Appendix II of this report. All waters in survey area. Object Detection Coverage Survey coverage was in accordance with the requirements in the PIs and the HSSD with the exception of holidays. In all cases, these holidays were caused by large school of fish and/or other marine life prohibiting the MBES from identifying the true seafloor. This interference resulted in artifacts in the processed data which did not accurately represent the seafloor (see Figure 2). In many cases, removal of these artifacts in the MBES surface introduced gaps in coverage. The number of areas this occurred in was extensive, therefore a Holiday Line file was created and executed. During the re-acquisition of data in some of these areas, commercial fishing vessels were encountered that prevented us from collecting the needed Holiday data. These areas were identified in in an associated H13518_Holidays.hob file that is located in the appendices of this report. Each of these gaps in coverage were examined in CARIS HIPS and SIPS, Subset Editor and determined not to degrade the confidence in the quality of the survey. These data gaps do not limit the ability to adequately verify charted depths. The charted shoal, 500 meters east of Solomons Island was not fully ensonified during acquisition, nor was any of the shore ward survey limits. These areas was deemed too shallow to survey safely with Bay Hydro II (see figure 3). CARIS HIPS and SIPS subset indicating marine life artifact that caused holidays in the all H13518 coverage. file:///D:/H13518/01_HDR/Images/Multimedia/Fish%20in%20Data.PNG H13518 survey coverage (in green), over laid onto H13518 Sheet Limits (in gray),indicating the area BHII deemed too unsafe to meet survey limits. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_Survey_Vs_PIs.PNG S5401 0.0 230.89 0.0 0.0 230.89 230.89 0.0 14.23 0.0 0.0 230.89 0.0 0.0 230.89 230.89 0.0 14.23 0.0 6.16 5 0 0 0 4.77 2021-06-25 2021-06-29 2021-06-30 2021-07-02 2021-07-06 2021-07-07 2021-07-13 2021-07-27 2021-07-31 2021-08-03 2021-08-10 2021-08-18 2021-09-09 2021-09-13 2021-09-15 2021-12-05 No multibeam data was acquired between 16 September 2021 and 05 December 2021 due to mechanical issues with Bay Hydro II and previously scheduled obligations of the crew. 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. S5401 17.3 1.8 R/V Bay Hydro II, S5401. file:///D:/H13518/01_HDR/Images/Multimedia/noaa_run.jpg MBES Kongsberg Maritime EM 2040CD Positioning and Attitude System Applanix POS MV 320 v5 Sound Speed System Valeport MiniSVS Sound Speed System SonTek CastAway-CTD Multibeam/Single Beam Echo Sounder/Side Scan Sonar crosslines acquired for this survey totaled 6.16% of mainscheme acquisition. Crosslines were collected, processed, and compared in accordance with Section 5.2.4.2 of the HSSD. To evaluate crosslines, a Variable Resolution (VR) CUBE surface using strictly mainscheme lines, and a Variable Resolution (VR) CUBE surface using strictly crosslines were created. From these two surfaces, a difference surface (mainscheme - crosslines = difference surface) was generated at a Variable Resolution (VR) (See Figure 5), and is submitted in the Separates II Digital Data folder. Statistics show the mean difference between the depths derived from mainscheme and crosslines was -0.01 meters with crosslines being deeper and 95% of nodes falling within +/- 0.16m (Figure 6). For the respective depths, the difference surface was compared to the allowable NOAA uncertainty standards using Pydro's Compare Grids tool. In total, 99.5% of the depth differences between H13518 mainscheme and crossline data were within allowable NOAA uncertainties (Figure 7). Depth differences between H13518 mainscheme (colored in gray) and H13518 crossline data. file:///D:/H13518/01_HDR/Images/Multimedia/H13518%20Depth%20Difference%20Surface%20Over%20Layed%20onto%20Mainscheme%20Only.jpg H13518 maincheme to crossline difference statistics. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_VR_300kHz_Mainscheme-Only-H13518_Xlines_VR_depth_delta.png H13518 mainscheme and H13518 crossline NOAA allowable uncertainty statistics. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_VR_300kHz_Mainscheme-Only-H13518_Xlines_VR_fracAllowErr_Freq.png ERS via VDATUM 0.0 0.09 S5401 2.0 0.0 0.0 0.5 In addition to the usual a priori estimates of uncertainty provided via device models for vessel motion and VDATUM, real-time and post processed uncertainty sources were also incorporated into the depth estimates of survey H13518. Real-time uncertainties were provided via EM 2040 CH MBES data and Applanix Delayed Heave RMS. Following post -processing of the real-time vessel motion, recomputed uncertainties of vessel roll, pitch, gyro, and navigation were applied in CARIS HIPS and SIPS via a Smoothed Best Estimate of Trajectory (SBET) RMS file generated in Applanix POSPac. H13518 junctions with two surveys from prior projects, H11450 and F00772. H11450 junctions H13518 in the eastern edge of the survey and northern edge east of Drum Point, see Figure 8. To evaluate this junction area, a 2m CUBE surface was created using only the H13518 data then differenced with the archived 2m BAG from H11450 (See Figure 9), using the CARIS Difference tool. H13518 and H11450 were then compared using Pydro's Compare Grids sub-program. Statistics show the data from H13518 and Junction Survey H11450 had good depth agreement with the mean difference being 0.13m with H13518 being deeper and 95% of nodes falling within +/- 0.23m, see Figure 10. The junction with H11450 are generally within the NOAA Allowable uncertainty in their areas of overlap, with 99.5% of the nodes passing (See Figure 11). H13518 also junctions F00772. This junction occurs along the northern edge of the survey, in the approaches to Back Creek northeast of Solomons Island (See Figure 12). To evaluate this junction area, a 50cm CUBE surface was created using only the H13518 data then differenced with the data from Survey F00772, using the CARIS Difference tool (see figure 13). H13518 and F00772 were then compared using Pydro's Compare Grids sub-program. Statistics show the data from H13518 and Junction Survey F00772 had good depth agreement with the mean difference being 0.04m with H13518 being deeper and 95% of nodes falling within +/- 0.13m, see Figure 14. The junction with F00772 are generally within the NOAA Allowable uncertainty in the area of overlap, with 99.5% of nodes passing, see Figure 15.. Area of junction between H13518 (in teal) and H11450 (in red). file:///D:/H13518/01_HDR/Images/Multimedia/H13518%20Junctioned%20with%20H11450.PNG H13518 2m and H11450 2m difference surface showing good agreement, over laid onto H13518 in gray. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_MBES_2m_H11450_VBES_2m%20Difference.PNG H13518 mainscheme to Junction Survey H11450 difference statistics. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_EM2040CD_2M_300kHz-H11450_MBVB_2m_MLLW_Combined_depth_delta.png H13518 mainscheme and Junction Survey H11450 NOAA Allowable Uncertainty Statistics. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_EM2040CD_2M_300kHz-H11450_MBVB_2m_MLLW_Combined_fracAllowErr_Freq.png H13518 50CM and F00772 50CM difference surface showing good agreement, over laid onto H13518 in gray. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_MBES_50CM_F00772_MBES_50CM_Difference.PNG Area of junction between H13518, in teal, and F00772 in red. file:///D:/H13518/01_HDR/Images/Multimedia/F00772%20Over%20Laid%20onto%20H13518%20with%20Subset.png H13518 mainscheme to Junction Survey F00772 difference statistics. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_EM2040CD_50CM_300kHz-F00772_MB_50cm_MLLW_final_depth_delta.png H13518 mainscheme and Junction Survey F00772 NOAA Allowable Uncertainty Statistics. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_EM2040CD_50CM_300kHz-F00772_MB_50cm_MLLW_final_fracAllowErr_Freq.png Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR. None Exist There were no conditions or deficiencies that affected equipment operational effectiveness. None Exist There were no other factors that affected corrections to soundings. Casts were conducted at a minimum of one every four hours during acquisition. Casts were conducted more frequently in area where tidal shifts caused variations in the make up of the water column or when there was a change in surface sound speed greater than two meters per second. All sound speed methods were used a detailed in the DAPR. All equipment and survey methods were used as detailed in the DAPR. SBET Issues One SBET issue was encountered while processing H13518 MBES data. On day number 224, one of the base stations that POSPac MMS tried to use to create the Smartbase SBET was malfunctioning and stopped collecting data. This could be seen as an height offset in the MBES surface when DN224 was combined into surface H13518_EM2040_VR_300kHz; specifically (see Figure 16), that DN224's data did not have proper depths and therefore, did not line up with the rest of the data collected for the project. Since this offset was seen every line collected on DN224, that day's MBES data was reprocessed using RTX SBET and the height offset was resolved. Smartbase SBET Issue encountered on DN224 file:///D:/H13518/01_HDR/Images/Multimedia/H13518%20SBET%20Issue.PNG Holidays On several occasions, a large school of fish and/or other marine life prohibited the MBES from identifying the true seafloor. This interference resulted in artifacts in the processed data which did not accurately represent the seafloor (see Figure 17). In some cases, removal of these artifacts in the MBES surface introduced gaps in coverage. Each of these gaps in coverage were examined in CARIS HIPS and SIPS, Subset Editor and determined not to degrade the confidence in the quality of the survey. These data gaps do not limit the ability of adequately verify charted depths. See the H13518_Holiday.hob file in Appendix II for the location of all of these gaps in coverage. CARIS HIPS and SIPS Subset Editor image of marine life prohibiting the MBES from identifying the true seafloor. file:///D:/H13518/01_HDR/Images/Multimedia/Fish%20in%20Data.PNG NOAA Allowable Uncertainty To verify that all data meet the accuracy specifications as stated in HSSD Section 5.1.3, the surface H13518_EM2040_VR_300kHz was finalized. The finalized surface was then analyzed Pydro's QC Tool, Grid QC. Figure 18 shows a graphical overview of the NOAA Allowable Uncertainty layer for the surface and corresponding statistics for the surface. Overall, over 99.5% of nodes from the surface meet or exceed NOAA Allowable Uncertainty specifications for H13518. H13518 NOAA Allowable Uncertainty graph. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_EM2040_VR_300kHz_Finalized.QAv6.tvu_qc.png Density Finalized surfaces were analyzed using the Pydro QC Tools Grid QC feature and the results are shown in Figure 19. Density requirements for H13518 were achieved with at least 99.5% of finalized surface nodes containing five or more soundings as required by HSSD Section 5.2.2.2. The few nodes that did not meet density requirements are due to sparse data in the outer beams, especially near steep slopes, and at the edges of the survey limits. H13518 density statistics. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_EM2040_VR_300kHz_Finalized.QAv6.density.png All data reduction procedures conform to those detailed in the DAPR. All sounding systems were calibrated as detailed in the DAPR. Backscatter was acquired within the Kongsberg.all file and is being submitted for processing by the branch. CARIS CARIS HIPS and SIPS 11.3.17 CARIS BASE Editor 5.5.14 NOAA Profile Version 2021 H13518_MB_VR_MLLW.csar CARIS VR Surface (CUBE) Variable Resolution 1.75 40.22 NOAA_VR Object Detection H13518_MB_VR_MLLW_Final.csar CARIS VR Surface (CUBE) Variable Resolution 1.75 40.22 NOAA_VR Object Detection The NOAA CUBE parameters defined in the HSSD were used for the creation of all CUBE surfaces in Survey H13518. The surfaces have been reviewed where noisy data, or "fliers," are incorporated into the gridded solutions causing the surface 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 v8, part of the QC Tools package within Pydro, was used to assist the search for spurious soundings following gross cleaning. Flier Finder was run multiple times for the 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. With smaller heights, Flier Finder began to incorrectly flag dynamic aspects of the seafloor such as steep drop offs resulting in hundreds of false positives. At this point, the hydrographer ceased using the tool and returned to manual cleaning for these dynamic regions of the seafloor. Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR. Mean Lower Low Water ERS via VDATUM S-E903-BH2-21_VDatumLimits_100m_NAD83-MLLW_geoid12b.csar Following the successful application of SBETs, ERS methods using VDATUM were used for reducing data to MLLW. ERS methods were used as the final means of reducing H13518 to MLLW for submission. North American Datum 1983 Projected UTM 18 Smart Base Horn Point, MD HNPT Loyola F, MD LOYF Corbin, VA CORB U.S. Naval Observatory Time Station USN7 Loyola O, VA LOYO Loyola LOYW, VA LOYW Vessel kinematic data were post-processed using Applanix POSPac processing software and Smart Base Positioning methods using Charlene as described in the DAPR. Smoothed Best Estimate of Trajectory (SBET) and associated error (RMS) data were applied to all MBES data in CARIS HIPS and SIPS. For further details regarding the processing and quality control checks performed, see the H13518 POSPAC Processing Logs located in the Separates folder. The Wide Area Augmentation System (WAAS) was used for real-time horizontal control during data acquisition. Two ENCs covered survey H13518; US5MD21M and US5MD31M, with US5MD31M being a small scale, cutout ENC of US5MD21M. These two ENCs were TINed using the TINing tool in CARIS Base Editor 5.5.14, interpolated, and then Warped using the same program's Warping Tool. Since ENC US5MD21M covers the eastern part of the survey area, as well as up river of the survey area, but not cover the majority of the survey area (See Figure 20), the TINing process incorrectly interpolated the area of the survey area around Solomons, MD that is not covered by the ENC. Therefore, two separate 0.5m surfaces were created from H13518, one surface to complete a chart comparison with each of the two ENCs. A sounding set was then created for each of the two surfaces, so that a visual comparison could be made between the ENC and it's corresponding 0.5m surface. Then a difference surface was made, comparing the ENC and the corresponding H13518 survey data. All data from H13518 should supersede charted data. In general, surveyed soundings agree with the majority of charted depths. A full discussion of the disagreements follows below. H13518 VR surface overlaid onto ENC US5MD21M. file:///D:/H13518/01_HDR/Images/Multimedia/H13518%20Overlaid%20onto%20ENC%20US5MD21M.PNG Sounding from H13518 are in a general agreement with charted depths on ENC US5MD21M, with all depths agreeing to 1 meter with the survey data being deeper than the charted depths on the ENC (See Figure 21). Contours derived from H13518 are in a general agreement with charted contours indicated on ENC US5MD21M along the western edge of Hog Point and in the offshore, deeper areas. However, the contours derived from H13518 on the eastern side of Hog Point indicate that the contours are migrating inshore and westward, creating a steeper eastern edge to the point (See Figure 22). H13518 survey data differenced with US5MD21M in green, with H13518 surveyed depths in black and ENC US5MD21M charted depths in red. file:///D:/H13518/01_HDR/Images/Multimedia/ENC%20US5MD21M%20Comarison.PNG H13518 contour difference with ENC US5MD21M at Hog Point, with H13518 derived contours in black and ENC contours in red. file:///D:/H13518/01_HDR/Images/Multimedia/H13518_Contour_Compare_US5MD21M.PNG Sounding from H13518 are in a general agreement with charted depths on ENC US5MD31M, with all depths agreeing to 1 meter with the survey data being deeper than the charted depths on the ENC (See Figure 23). Contours derived from H13518 are in a general agreement with charted contours indicated on ENC US5MD21M, with some movement on the eastern edge of points, shoals and Solomons Island (See Figure 24). H13518 survey data differenced with US5MD31M in green with H13518 surveyed depths in black and ENC US5MD31M charted depths in red. file:///D:/H13518/01_HDR/Images/Multimedia/ENC%20US5MD31M%20Comparison.PNG H13518 indicated movement of charted contours east of Solomons Island. file:///D:/H13518/01_HDR/Images/Multimedia/Shoal%20movement%20East%20of%20Solomons.PNG US5MS21M 40000 26 2021-09-22 2021-09-22 US5MD31M 10000 14 2021-09-30 2021-10-19 Three DTONs were discovered in H13518's surveyed area; all three of which affect ENC US5MD31M. Two are located in the approach to Solomons Harbor, between the island's eastern point and the charted shoal east of the island; and the third is located approximately 1300m south of the charted shoal, east of Solomons inlet (Figure 25). These three DTONs were reported to the Pacific Hydrographic Branch per HSSD 1.6.3 and attributed in the Final Feature File. One potentially hazardous shoal exists in H13518 survey area (See figure 26). The majority of this charted shoal was too shallow to survey with the R/v Bay Hydro II, however as much of the shoal was surveyed as safety would allow. This shoal is delineated by ATONS which were found to be on station and survey their intended purpose, see H13518_FFF.000. Position of DTONS found in survey H13518. file:///D:/H13518/01_HDR/Images/Multimedia/DTONS_Chartlet_1.PNG H13518 Charted shoal east of Solomons Harbor. file:///D:/H13518/01_HDR/Images/Multimedia/Charted%20Shoal.PNG There are multiple features assigned to H13518, see H13518_FFF.000 for descriptions, remarks, and recommendation. Multiple uncharted features were found during this survey. All uncharted features have been address in the Final Feature File , see H13518_FFF.000 for more detail. 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. ATONS were investigated to the best of the field unit's ability to determine proper placement and to confirm they are serving their intended purpose, see the Final Feature File (H13518_FFF.000) for more details. No Maritime Boundary Points were assigned for this survey. Six bottom samples were assigned with H13518 (see Figure 27 for sample position), however, only five bottom samples were acquired in accordance with the Project Instructions for Survey H13518; three unsuccessful attempts were made to collect the sixth bottom sample. All bottom samples were entered into the H13518 Final Feature File. Figure 27: H13518 Assigned bottom sample positions indicated by the symbol "T". file:///D:/H13518/01_HDR/Images/Multimedia/H13518%20Bottom%20Samples.PNG One overhead feature was assigned to survey H13518. The Governor Thomas Johnson Memorial Bridge spans the Patuxent River along the western edge of the survey area (see Figure 28). Although a detached position was not acquired on any of the bridge's support structures, the bridge pylons as seen in the MBES data indicates that the bridge is charted correctly on ENC US5MD31M. An air gap measurement was not conducted to ascertain the height of the bridge, see H13518_FFF.000. Governor Thomas Johnson Memorial Bridge (in black) spanning the Patuxent River along the western edge of the H13518 survey area. file:///D:/H13518/01_HDR/Images/Multimedia/Charted%20TJ%20Bridge.PNG One charted submarine cable area exists spanning the Patuxent River along survey H13518's western edge, see H13518_FFF.000 (Figure 29). No cable was seen protruding through the riverbed in any of the MBES data in this area, indicating that it is sufficiently buried. Charted submarine cable area as indicated by dashed red line. file:///D:/H13518/01_HDR/Images/Multimedia/Charted%20submarine%20cable%20area.PNG No platforms exist for this survey. No ferry routes or terminals exist for this survey. No abnormal seafloor or environmental conditions 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 ENC scales 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 Specifications and Deliverables, 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 Kevin Tennyson Chief of Party 2022-03-03 Robert W. Mowery Sheet Manager 2022-03-03