OPR-E347-KR-22 Central Chesapeake Bay, MD Central Chesapeake Bay Leidos H13515 5 Prospect Bay Maryland United States 5000 2023 Bridget W. Bernier Basic Hydrographic Survey 2022-08-23 2022-09-18 2023-04-30 Multibeam Echo Sounder Side Scan Sonar Multibeam Echo Sounder Backscatter meters UTC Atlantic Hydrographic Branch Contract: 1305M220DNCNJ0056/TO-0003. Contractor: Leidos, 221 Third Street, Newport, RI 02840 USA. Subcontractors: Northstar Marine, Inc., 36 Clermont Drive, Clermont, NJ 08210; OARS, 8705 Shoal Creek Blvd, Suite 109, Austin, TX 78757. Leidos Doc. 22-TR-025. All times were recorded in UTC. Final data are corrected to North American Datum of 1983 (NAD83) 2011 realization 2010 (NAD83(2011)2010.0), UTM Zone 18N. 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 Contractors) CC0-1.0 https://creativecommons.org/publicdomain/zero/1.0/ https://creativecommons.org/publicdomain/zero/1.0/legalcode These data were produced under contract with NOAA and any potential copyright was assigned to NOAA. NOAA waives any potential copyright and related rights in these data worldwide through the Creative Commons Zero 1.0 Universal Public Domain Dedication (CC0). Contractor H13515 was located within the Central Chesapeake Bay, Maryland within Prospect Bay (Figure 1). The survey was conducted in accordance with coverage requirements listed in the Project Instructions (PI) OPR-E347-KR-22. 38.971578 76.254784 38.842314 76.20576100000001 H13515 Survey Bounds file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_01.png Survey limits were acquired in accordance with the requirements in the PI and the Hydrographic Survey Specifications and Deliverables (HSSD), March 2022. The Chesapeake Bay is the largest estuary in North America and heavily trafficked by commercial and recreational vessels as tourism, fishing, and marine commerce are economically vital for the region. In addition to fishing and tourism traffic, commercial vessels transit through the project area to reach the Port of Baltimore, which is ranked as a top 15 port in container and tonnage, and a top 10 port for dry bulk. The majority of the prior data in the project area spans from the 1880s to 1940s. The bathymetric data vintage coupled with numerous storms and hurricanes having potentially changed the seabed over the last century raises a need to survey the area. In addition, the Ever Forward container ship ran aground near the Craighill Channel in March 2022, and was removed after 35 days. 206,230 cubic yards of material was dredged and taken to Poplar Island. The data from this project will provide modern bathymetry for updating National Ocean Service nautical charting products improving the safety of maritime traffic and commerce as well as supporting the Seabed 2030 global mapping initiative. 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. Leidos warrants only that the survey data acquired by Leidos and delivered to NOAA under Contract 1305M220DNCNJ0056 reflects the state of the sea floor in existence on the day and at the time the survey was conducted. H13515 was surveyed in accordance with the following documents: 1. 1305M220DNCNJ0056 signed.pdf, received 24 August 2022 2. Hydrographic Survey Specifications and Deliverables (HSSD), March 2022 3. PRF.000, received 24 August 2022 4. CSF.000, received 24 August 2022 5. OPR-E347-KR-22 Project Brief, held 07 September 2022 Sheets 1, 3, 4, 5, 7, 8, and 9 Complete Coverage (Refer to HSSD Section 5.2.2.3) Inshore limit to 8 meters water depth Sidescan may be acquired at an altitude of 6-20% of the range scale. Survey coverage achieved was in accordance with the requirements in the PI and the HSSD (Figure 2). Leidos chose to achieve the coverage requirement using Complete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam). In many areas of H13515 the inshore limit of the Navigable Area Limit Line (NALL) was reached seaward of the assigned survey bounds. Leidos surveyed to the NALL as defined by HSSD Section 1.3.2; within the surveyed bounds. However, due to safety concerns for personnel and survey equipment, some areas were not fully covered with multibeam echo sounder (MBES) data to exactly the 3.5-meter depth contour. This was due limited vessel maneuverability around the shoal depth areas, at these discrete locations. In these areas the side scan sonar (SSS) swath extended shoreward of the MBES swath, and indicated that the seafloor continued to rise abruptly and in a manner that the vessel could not navigate over for further MBES coverage; while also indicating in the SSS data that there were no significant objects that would require individual cartographic representation. Final Bathymetry Coverage for H13515 file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_02.png R/V Oyster Bay II 0.0 0.0 0.0 0.0 0.0 265.24 0.0 9.97 0.0 0.0 0.0 0.0 0.0 0.0 265.24 0.0 9.97 0.0 3.76 2 0 0 0 7.09 2022-09-18 2022-09-20 2022-10-23 2022-10-27 2022-10-29 2022-12-07 2023-01-06 2023-03-18 2023-03-19 2023-03-24 2023-03-26 2023-04-25 2023-04-27 2023-04-30 Leidos used their ISS-2000 software on a Windows platform to acquire these survey data. Survey planning and data analysis were conducted using the Leidos SABER software on Linux platforms. Side scan sonar (SSS) data were collected on a Windows platform using Klein’s SonarPro software. Subsequent processing and review of the SSS data, including the generation of coverage mosaics, were accomplished using SABER. A detailed description of the systems and vessel used to acquire and process these data is included in the Data Acquisition and Processing Report (DAPR) for OPR-E347-KR-22, delivered previously with H13511. There were no variations from the equipment configuration described in the DAPR. R/V Oyster Bay II 30.0 3.0 R/V Oyster Bay II file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_03.png The R/V Oyster Bay II (Figure 3) was used to collect multibeam echo sounder (MBES) (RESON SeaBat T50), side scan sonar (SSS) (Klein 4900), and sound speed data during twelve hours per day survey operations. A detailed description of the vessels used is included in the DAPR. MBES Teledyne RESON SeaBat T50-R SSS Klein Marine Systems System 4900 Positioning and Attitude System Applanix POS MV 320 v5 Sound Speed System AML Oceanographic BaseX MBES Backscatter Teledyne RESON SeaBat T50-R Multibeam echo sounder crosslines acquired for this survey totaled 3.76% of mainscheme acquisition. The resulting crossline to mainscheme percentage met the requirement to achieve approximately four percent of mainscheme mileage for a complete coverage multibeam survey (Section 5.2.4.2 of the HSSD). H13515 requirements were for Complete Coverage, Option B, based on the classifications defined in Section 5.2.2.3 of the HSSD. Mainscheme lines were spaced 70 meters apart, and crosslines were were generally 1500 meters apart. In the field, hydrographers conducted daily comparisons of mainscheme to near nadir crossline data to ensure that no systematic errors were introduced and to identify potential problems with the survey systems. After the application of all correctors and completion of final processing in the office, separate CUBE PFM grids were built at 1-meter resolution for all data. One grid contained the full valid swath (±65° from nadir, Class 2) of mainscheme multibeam and the other included only the near nadir swath (±5° from nadir, Class 1) crossline data. The difference grid was created by subtracting the 1-meter H13515 mainscheme CUBE depths from the 1-meter H13515 crossline CUBE depths. These results are summarized in Figure 4. The SABER Frequency Distribution Tool was used to analyze the difference grid created from the mainscheme and crossline PFM grids and the results of the analysis were compiled into the following section. Section 5.2.4.2 of the HSSD states that the depth difference values are to be within the maximum allowable Total Vertical Uncertainty [TVU]. For H13515, 100% of the comparisons were within TVU results for crossing analysis are summarized in Figure 5 and Figure 6. Summary of Crossing Analysis file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_04.png Tabular Results Crossing Analysis, Crosslines vs. Mainscheme Lines file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_05.png Plot of Crossing Analysis Crosslines vs. Mainscheme Lines file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_06.png ERS via VDATUM 0.092 0.2 R/V Oyster Bay II 1 1 1 1 For specific details on the use and application of the SABER Total Propagated Uncertainty (TPU) model, refer to the DAPR. Once the TPU model was applied to the GSF bathymetry data, each beam was attributed with the horizontal uncertainty and the vertical uncertainty at the 95% confidence level. The vertical and horizontal uncertainty values, estimated by the TPU model for individual multibeam soundings, varied little across the dataset, tending to be most affected by beam angle. Individual soundings that had vertical and horizontal uncertainty values above IHO S-44 6th Edition, Order 1a were flagged as invalid during the uncertainty attribution. As discussed in the DAPR, SABER generates two vertical uncertainty surfaces: the Hypothesis Standard Deviation (Hyp. StdDev) and the Hypothesis Average Total Propagated Uncertainty (Hyp. AvgTPU). A third vertical uncertainty surface is generated from the larger value of these two uncertainties at each node and is referred to as the Hypothesis Final Uncertainty (Hyp. Final Uncertainty). The final H13515 1-meter PFM CUBE surface contained final vertical uncertainties that ranged from 0.200 meters to 0.500 meters. The IHO Order 1a maximum allowable vertical uncertainty was calculated to range between 0.500 to 0.531 meters, based on the minimum CUBE depth (1.177 meters) and maximum CUBE depth (13.771 meters). Results from the SABER Check PFM Uncertainty function did not identify any nodes in the final H13515 1-meter PFM CUBE surface with final vertical uncertainties that exceeded IHO Order 1a allowable vertical uncertainty. The SABER Frequency Distribution Tool was also used to review the Hyp. Final Uncertainty surface within the final H13515 1-meter CUBE PFM grid. Results showed that 99.02% of all nodes had final uncertainties less than or equal to 0.210 meters. Per the PI, junction analysis was performed between H13515 and the surveys listed in the table below and illustrated in Figure 7; results are discussed below. Analysis of H13515 to H13685 will be provided within the H13685 Descriptive Report as final analysis and processing efforts for H13685 remain on-going. General Locality of H13515 with Junctioning Surveys file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_07.png H13512 20000 2023 Leidos S Junctioning survey H13512 was conducted in 2023 and junctions to the south of H13515. For this analysis the H13512 CUBE depth surface was compared to the H13515 CUBE depth surface. Junction analysis was conducted on the common area of these two sheets, with an overlapping area approximately 4,410 by 405 meters along the southern edge of H13515. Observed depths within the common area were 1.356 to 10.786 meters which resulted in a calculated allowable TVU range of 0.500 to 0.519 meters. The difference grid was generated by subtracting the H13512 data from the H13515 data. Positive values indicate that H13515 depth data were deeper than H13512 depth data. Throughout the common area, H13515 CUBE depths were deeper 94.96% of the time and were shoaler 4.83% of the time (Figure 16) with 100% of the comparisons within 0.387. The distribution is skewed positive of zero as presented in Figure 17. 100.00% of the comparisons were 0.387 meters or less, within the calculated allowable TVU range. Tabular Results Junction Analysis H13515 vs. H13512 file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_08.png Plot of Junction Analysis H13515 vs. H13512 file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_09.png H13514 20000 2023 Leidos S Junctioning survey H13514 was conducted in 2023 and junctions to the south of H13515. For this analysis the H13514 CUBE depth surface was compared to the H13515 CUBE depth surface. Junction analysis was conducted on the common area of these two sheets, with an overlapping area approximately 242 by 307 meters along the southern edge of H13515. Observed depths within the common area were 2.581 to 4.825 meters which resulted in a calculated allowable TVU range of 0.501 to 0.504 meters. The difference grid was generated by subtracting the H13514 data from the H13515 data. Positive values indicate that H13515 depth data were deeper than H13514 depth data. Throughout the common area, H13515 CUBE depths were deeper 81.40% of the time and were shoaler 17.70% of the time (Figure 10) with 100% of of the comparisons were 0.106 meters or less, within the calculated allowable TVU range. The distribution is skewed positive of zero as presented in Figure 11. Tabular Results Junction Analysis H13515 vs. H13514 file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_10.png Plot of Junction Analysis H13515 vs. H13514 file:///B:/OPR-E347-KR-22/Surveys/H13515/01_HDR/Reports/Descriptive_Report/SupportFiles/H13515_Figure_11.png Sonar system quality control checks were conducted as detailed in the DAPR. None Exist There were no conditions or deficiencies that affected equipment operational effectiveness. Factors Affecting Soundings Dense biological interference were observed during discrete areas and during various days of survey which required numerous holiday reruns. Additionally, throughout survey acquisition both commercial and recreational fishing activity was heavy causing deviations in the survey acquisition lines requiring numerous holiday reruns. The end result was that there were no significant impacts to the final sounding data. On the R/V Oyster Bay II, the AML BaseX2 was the primary system used to collect SSP data, refer to the DAPR for additional details. SSP data were obtained at intervals frequent enough to meet depth accuracy requirements. All sound speed profiles applied for online bathymetry data collection were acquired within 500 meters of the bounds of the survey area as specified in Section 5.2.3.3 of the HSSD. Confidence checks of the sound speed profile casts were routinely conducted by comparing at least two consecutive casts taken with different SSP sensors. All individual SSP files are delivered with the H13515 data and are broken out into sub-folders, which correspond to the purpose of each cast. Also, all individual SSP files for H13515 have been concatenated into two separate files based on the purpose of the cast, provided in CARIS format files (.svp), and delivered under (H13515/Processed/SVP/CARIS_SSP) on the delivery drive. In accordance with HSSD Section 8.3.6, SSP files were also converted to NCEI format, as detailed in the DAPR, and provided as a separate delivery to NCEI. Refer to the DAPR for additional details. All equipment and survey methods are detailed in the DAPR. Multibeam Coverage Analysis Leidos chose to achieve the coverage requirement using 100% SSS coverage with concurrent MBES. To achieve this coverage, the SSS was set to 50-meter range scale, and main scheme survey lines were collected 80-meters to ensure 100% SSS or 200% SSS coverage was achieved. The SABER Gapchecker program was used to flag MBES data gaps within the CUBE surface. The entire surface was visually scanned for holidays at various points during the data processing effort. Additional survey lines were run to fill any holidays that were detected as defined for complete coverage surveys in Section 5.2.2.3 of the HSSD and email correspondence dated 02/22/2023 (refer to Project Correspondence for additional details). Bathymetric data and side scan sonar imagery were reviewed and bathymetric splits were acquired if deemed necessary per Hydrographer’s discretion, as noted in Section 5.2.2.1 of the HSSD. A final review of the CUBE Depth surface for H13515 showed that there were no holidays as defined for complete coverage surveys in Section 5.2.2.3 of the HSSD or NOAA provided guidance (02/22/2023). Any three by three node gaps were along the outer swath data beyond side scan nadir coverage. The final CUBE PFM grids were examined for the number of soundings contributing to the chosen CUBE hypotheses for each node by running SABER’s Frequency Distribution Tool on the Hypothesis Number of Soundings (Hyp. # Soundings) surface. The Hyp. # Soundings surface reports the number of soundings that were used to compute the chosen hypothesis. Analysis was conducted on the Hyp. # Soundings surface of the PFM grid to ensure that the requirements for Complete Coverage surveys (HSSD Section 5.2.2.3) were met. Within the final 1-meter CUBE PFM grid 99.40% of all nodes contained five or more soundings. As noted in Section A.4, the assigned survey bounds were achieved across H13515 except where the inshore limit of the NALL was reached or the shoreline bathymetry made it unsafe of equipment and crew to continue into shoaler depths. All data reduction procedures conform to those detailed in the DAPR. All sounding systems were calibrated as detailed in the DAPR. Side Scan Sonar (SSS) Coverage Analysis: For all details regarding SSS data processing, see the DAPR. Leidos chose to adhere to the coverage requirements in the PI using Complete Coverage, Option B (100% side scan sonar coverage with concurrent multibeam). Leidos generated two separate coverage mosaics at 1-meter cell size resolution as specified in Section 8.2.1 of the HSSD (See section B.2.9 for additional information). The first 100% and second 100% coverage mosaics were independently reviewed using tools in SABER to verify data quality and swath coverage. The SABER Gapchecker routine was used to flag data gaps within each of the 100% SSS coverage mosaics. Additionally, the entirety of each SSS surface was visually scanned for holidays at various points during the data processing effort. Additional survey lines were run to fill any holidays that were detected. All coverage mosaics are determined to be complete and sufficient to meet the requirements contained within the PI and HSSD. Each 100 percent coverage mosaic is delivered as a single georeferenced raster file (datum of NAD-83) in floating point GeoTIFF format, as specified in Sections 8.2.1 and 8.3.3 in the HSSD. Multibeam Echo Sounder Seafloor Backscatter: For all details regarding MBES backscatter acquisition and processing see the DAPR. Leidos generated a MBES backscatter at 2-meter cell resolution; per HSSD. The MBES backscatter mosaic was reviewed for data quality and coverage. The MBES backscatter data acquired were written to the GSF in real-time by ISS-2000 and are delivered in the final GSF files for this sheet under the Processed/Sonar_Data/H13515_MB directory. The MBES backscatter mosaic was determined to be complete and sufficient to meet the requirements contained within the PI and HSSD. The coverage mosaic is delivered as a single georeferenced raster file (datum of NAD-83) in floating point GeoTIFF format, as specified in Section 6.2.4.2 in the HSSD. Leidos SABER 5.4.1.6.1 Leidos SABER 5.4.1.6.1 QPS FMGT 7.10.3 NOAA Profile Version 2022 The primary data processing software used for both bathymetry and imagery was SABER. H13515_MB_1m_MLLW_Final BAG 1 1.177 13.771 N/A Complete coverage, Option B H13515_SSSAB_1m_900kHz_1of1 SSS Mosaic 1 N/A 100% SSS H13515_SSSAB_1m_900kHz_2of2 SSS Mosaic 1 N/A 200% SSS H13515_MBAB_2m_OysterBayII_300kHz_1of1 MB Backscatter Mosaic 2 N/A Multibeam Backscatter Coverage Complete Coverage Section 5.2.2.2 of the HSSD requires 1-meter node resolution for depths ranging from zero meters to 20 meters. Leidos generated a CUBE PFM grid for H13515 at 1-meter resolution (Figure 2). The final gridded bathymetry data are delivered in Bathymetric Attributed Grid (BAG) format. The BAG files were exported from the CUBE PFM grid as detailed in the DAPR. In accordance with HSSD Section 2.2, the horizontal datum for this project is NAD83. HSSD Section 2.2 states that the “only exception for the NAD83 datum requirement is that the S-57 Final Feature File (Section 7.3) will be in the WGS84 datum to comply with international S-57 specifications”. As discussed in the DAPR Section C.7, for every feature flag in a MBES GSF file, SABER converts the position from the NAD83 datum to the WGS84 datum to generate the S-57 file and comply with HSSD and IHO requirements. Feature positions meet the precision stated in HSSD Section 7.4 for each respective datum. Depending on geographic reference there may be approximately a 1-meter difference comparing positions between NAD83 and WGS84 datums. Therefore, if the feature overrides from the BAG surface (NAD83) are compared to the Final Feature File S-57 positions (WGS84) it is anticipated that there could be positional differences exceeding those listed in Section 7.4 of the HSSD. Additional information discussing the vertical and horizontal control for this survey can be found in the DAPR. Mean Lower Low Water ERS via VDATUM OPR-E347-KR-22 _NAD83_VDatum_MLLW.cov Refer to the DAPR for details regarding the application of VDatum to the MBES data files. No final tide note was provided nor was it required from NOAA Center for Operational Oceanographic Products and Services (CO-OPS). North American Datum 1983 (2011) Projected UTM 18 The vessel kinematic data (POS/MV files) were post-processed in Applanix POSPac software using the Applanix PP-RTX solution to generate the Smoothed Best Estimate of Trajectory (SBET) solutions which were applied through SABER to the multibeam data. Refer to the DAPR for additional information and for details regarding all antenna and transducer offsets. Any soundings with total horizontal uncertainties exceeding the maximum allowable IHO S-44 6th Edition Order 1a specifications were flagged as invalid and therefore were not used in the CUBE depth calculations. Chart comparisons were conducted using a combination of SABER and CARIS’ HIPS and SIPS. H13515 data met data accuracy standards and bottom coverage requirements. Leidos recommends updating the common areas of all charts using data from this survey. Review showed that the H13515 CUBE data were varied in agreement with charted depths compared to the ENCs listed in Section D.1.1. CUBE depths from H13515 generally agreed well with charted depths. Charting recommendations for new features and updates to charted features, are documented in the H13515 S-57 FFF. Additional charted objects are discussed in later sections. United States Coast Guard (USCG) District 5 LNM publications were reviewed for changes subsequent to the date of the Project Instructions and before the end of survey. The LNM reviewed were from week 35/22 (30 August 2022) until week 24/23 (13 June 2023). US5MD17M 40000 19 2021-12-03 2023-02-09 US5MD18M 40000 17 2022-01-28 2023-04-07 Refer to and Section D.1.4 for significant shoals or hazardous features within the area covered by this survey. Leidos submitted the following DTON reports to the Atlantic Hydrographic Branch (AHB) in S-57 format per HSSD: -H13515_DTON_01.000, submitted to AHB 2023-01-27, NDB registration DD-37664 -H13515_DTON_02.000, submitted to AHB 2023-01-27, NDB registration DD-37664 -H13515_DTON_03.000, submitted to AHB 2023-01-27, NDB registration DD-37664 -H13515_DTON_04_05.000, submitted to AHB 2023-07-18,not registered at time of delivery There were numerous assigned charted features in the final CSF (CSF.000) within the SOW of H13515. Per HSSD Section 8.1.4, these charted features are not addressed in this section, refer to the H13515 S-57 FFF (H13515_FFF.000) for all the details and recommendations regarding these features. See the H13515 S-57 FFF for all the details and recommendations regarding new uncharted features investigated. During the course of H13515 survey operations, fishing gear and temporary floats were observed throughout the survey area. When a temporary fishing surface float was identified and correlated to objects in the MBES data, as these data were not true seafloor the MBES data were invalidated to no longer contributed to a CUBE surface. In many cases, where it was not possible to confirm the fishing gear were not derelict or tied to a surface float, the object was retained in the MBES data. See Section B.2.5 for more information. Per the HSSD Section 7.3.6, temporary uncharted buoys associated with fishing activity were not provided in the FFF. Associated contacts are provided within the SSS Contacts S-57. There were no assigned channels within the H13515 SOW from the final CSF. However, the survey area was coincident to Safety Fairway (FAIRWY) to the Wells Cove (US5MD18M). H13515 CUBE depths were in agreement with currently charted depths. While there were no assigned Aids to Navigation (ATON) within the SOW of H13515 from the final CSF; there were numerous USCG and privately maintained fixed and floating ATONs within H13515. Per HSSD Section 7.3.6 and the CSF, ATONs found on-station are not provided within the FFF. Associated contacts are provided within the SSS Contacts S-57. No Maritime Boundary Points were assigned for this survey. In accordance with both the PI and Section 7.2.3 of the HSSD, bottom characteristics were obtained for H13515. Bottom characteristics were acquired at the two locations assigned in the final PRF (PRF.000). Leidos did not modify the bottom sample locations from the location proposed by NOAA in the PRF. Bottom characteristics are included in the S-57 FFF. In addition, images of the sediment obtained for each bottom sample are referenced in the S-57 FFF and are included on the delivery drive under the folder H13515/Processed/Multimedia. Overhead features were coincident to H13515 survey limits. Per the CSF investigation requirements these objects were not included in the S-57 FFF. The bridge over Kent Island Narrows was observed to be present and adequately charted (ENC US5MD18M). No submarine features exist for this survey. Assigned platforms to H13515 were not addressed as they were inshore of NALL. No ferry routes or terminals exist for this survey. Bottom features within Kent Island Narrows south of the Kent Island Narrows Bridge were found to have migrated over the course of survey. The shifting sand waves created artifacts in the CUBE depth solution. Therefore; to reduce the artifact when there was sufficient data in a newer MBES pass the previous MBES data were invalidated. Smaller artifacts may be present where the two data passes meet. No other abnormal seafloor or environmental conditions, as defined in Section 8.1.4 of the HSSD, exist within this survey area other than those discussed in Section B.2.5 and D.1.2. No construction or dredging was observed during H13515 data acquisition. 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 Hydrographic Survey Specifications and Deliverables, Project Instructions, and Statement of Work. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required. Previously, or previously, submitted deliverables for OPR-E347-KR-22 are provided in the table below. Bridget W. Bernier Data Processing Manager 2023-07-18 OPR-E347-KR-22 Final Project Summary Report.pdf 2023-05-31 OPR-E347-KR-22_Marine_Species_Awareness_Training_Record.pdf 2023-06-21 OPR-E347-KR-22_Coast Pilot Review Report.pdf 2023-06-22 OPR-E347-KR-22_DAPR.pdf 2023-07-17 H13511_DR.pdf 2023-07-17