OPR-B370-NRT5-14Eastern Long Island Sound, NYNorth Shore of Long Island SoundNavigation Response Team 5H125091Long Rock to Duck IslandConnecticutUnited States100002014LTJG Andrew ClosNavigable Area2014-04-242014-07-302014-11-09Multibeam Echo SounderSide Scan SonarmetersUniversal Transverse Mercator (UTM)UTCPacific Hydrographic BranchNOAAThe area surveyed is offshore of Westbrook, CT and includes Duck Island in the west to Crane Reef and Long Rock in the East. The survey extends from the NALL to approximately 3 nautical miles in to Long Island Sound.41.27507572.491108333341.216047222272.4105333333H12509 Survey LimitsSupportFiles\Survey_Area.bmpThe original sheet limits included with the project instructions were altered to "square off" the boundary between H12509 and H12510. Please see the project correspondence folder for further explanation of these changes.Southwest corner of sheet, original limits shown in red, revised survey outline shown in blue.SupportFiles\SheetLimitModifications.bmpThis project is being conducted in support of NOAA's Office of Coast Survey to provide contemporary hydrographic data in order to update the nautical charting products and reduce the survey backlog within the area. In addition, data from this project will support the Long Island Sound Seafloor Mapping Initiative in New York and Connecticut.The entire survey is adequate to supersede previous data.Coverage requirements were met for H12509 using 200% SSS with concurrent MBES with backscatter. Object Detection MBES was acquired in some near shore areas where it was unsafe to tow or difficult to maneuver with the SSS. The four meter curve was developed to fullest extent possible, however, there are some areas where it was not attained due to safety concerns (figures 4 and 5, below). Near Long Sand Shoal, two SSS holidays exist (see figure 6 below). In both cases 100% coverage was achieved and the vicinity is free of rocks and other obstructions. Additionally, over Long Sand Shoal, only 100% coverage with concurrent MBES was attained, but this area is inshore of the 4 meter contour. Furthermore, Long Sand Shoal was surveyed thoroughly during a 2013 survey, H12508.Nearshore area where four meter contour was not reached. Red areas indicate where the four meter contour was found.SupportFiles\4mCurve1.bmpNearshore area where four meter contour was not reached. Red areas indicate where the four meter contour was found.SupportFiles\4mCurve2.bmpSSS holiday in 200% coverage. These holidays were covered completely by 100% SSS and some MBES data.SupportFiles\SSSHolidays.bmpThe survey area is located offshore of Westbrook, CT. The coverage comprises 200% sidescan with concurrent multibeam. SupportFiles\Section A4 Survey Coverage.jpgS3002066.9000390.2043.60066.9000390.2043.609.52100008.572014-07-302014-08-042014-08-052014-08-062014-08-072014-08-112014-08-182014-08-202014-08-262014-08-282014-09-032014-09-042014-09-232014-09-292014-11-042014-11-09Refer 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.S3002300.75S3002SupportFiles\nrt_underway.jpgApplanixPOS/MV v5Positioning and Attitude SystemTrimbleSPS361Positioning SystemKongsbergEM3002MBESEdgetech4125SSSAMLMicro XSound Speed SystemSeabird19 PlusConductivity, Temperature, and Depth SensorS3002 acquired 43.6 linear nautical miles of MBES cross lines, equating to 9.5% of mainscheme MBES data. Crosslines were compared to mainscheme using a difference surface, created in CARIS BathyDataBase. Using the difference surface, every instance of overlap was evaluated. The mean was 0.05 meters and the standard deviation was 0.11 meters. Survey H12509 complies with section 5.2.4.3 of the HSSD (2014 ed). Additional comparison was made using CARIS Subset Editor and a 50 centimeter BASE surface to visually identify areas of mainscheme/crossline disagreement. The highest areas of disagreement occurred near sand waves. S30022N/A0.5H12509 utilized a TCARI grid, which includes uncertainty values for each node. Therefore, TPU values in CARIS were left at zero during TPU calculation. Total Propagated Uncertainty was then evaluated to ensure compliance with section 5.1.3 of NOAA's Hydrographic Survey Specification and Deliverables (HSSD). First, the maximum allowable uncertainty for each node was calculated. Second, the ratio between actual uncertainty and maximum allowed uncertainty is found for each node. The resulting 'Order_1a' layer was filtered using a color map to show any areas where actual uncertainty exceeded the maximum allowed uncertainty. Statistics were computed for the 4 meter finalized BASE surface and of the 1,898,135 nodes, 2 fell outside acceptable levels which equates to greater than 99.99% of nodes meeting Order 1a specifications. Additionally, Order 1a statistics were computed for the finalized 50cm BASE surface and of the 110,061,461 nodes, 0 fell outside acceptable levels. Finally, statistics were calculated on the finalized 1 meter BASE surface and of the 6,627,830, 51 fell outside of acceptable levels, equating to greater than 99.9% of nodes meeting Order 1a specifications. Areas of highest uncertainty occurred on sand waves at the southern portion of the sheet. H12509 junctions with H12510 on the west and H12508 on the east. MBES data was available from both surveys, so detailed comparisons were made. Difference surfaces were created for each overlapping area and statistics were computed to assess the level of agreement.H12510100002014Navigation Response Team 5WComparisons between H12509 and H12510 showed extremely high levels of agreement, which was expected since both surveys were carried out by the same vessel within one to two months of each other. The mean difference was 1.3 centimeters and the standard deviation was 7.8 centimeters. Difference Surface Statistics and Histogram, H12510.SupportFiles\H12510_DiffStats.bmpH12508100002013Navigation Response Team 5EH12509 also compared well to H12508, but some areas of disagreement were noticed for the following reasons. 1. A large portion of the overlap occurs over a sand bar in the southern portion of the survey where migrating sand waves are present and the highest levels of disagreement (up to 5 meters) were noticed here. 2. The surveys took place a year apart from one another, so the dynamic bottom type had time to change. Difference Surface Statistics and Histogram, H12508.SupportFiles\H12508_DiffStats.bmpSAR: A further examination was made of the large disagreements in the junction comparison between H12509 and H12508 to determine if there were data issues, if the shoal itself were migrating, or if the shifting sands were responsible for the large discrepancies in depths. The depth differences between H12508 and H12509 can be explained from two sources. The first source is out beam noise having been retained in the H12508 gridded data, accounting for depth differences of over 4-5m. The second - and most prevalent - depth differences come from notable sand wave peaks in one survey overlapping with notable sand wave depressions from the other. Taken together, these depth differences easily combine into 4-5m depth disagreements. It can be confidently said that shifting sand waves account for the large range of depth differences between H12508 and H12509.Sonar system quality control checks were conducted as detailed in the quality control section of the DAPR.None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.None ExistThere were no other factors that affected corrections to soundings.CTD casts were typically taken every two to three hours in the deepest area being surveyed at the time. The sound velocity profiles were applied to the MBES lines in Caris using the "nearest in time," method.Sound speed profiles in the area are most greatly affected by diurnal heating and cooling, and salinity fluctuations from the ebb and flood of the tide. The "nearest in time," method was applied to the data and no effects of refraction or other sound velocity artifacts affecting the data were noticed. All equipment and survey methods were used as detailed in the DAPR.All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.Raw Backscatter was logged in the .all file. Backscatter was not processed by the field unit. As a part of the Long Island Seafloor Mapping Initiative, backscatter was collected and delivered, along with other raw data and processed MBES BASE surfaces, to the National Centers for Coastal Ocean Science (NCCOS). CarisHIPS/SIPS81102015-01-16ProcessingNOAA Profile V_5_3_2All MBES and side scan data were converted and processed using a CARIS HIPS and SIPS 8.1.7. After acquisition was completed, data cleaning and additional processing was carried out on a different computer running CARIS HIPS and SIPS 8.1.10. No errors or anomalies were noticed when making this transition. The Hydro Systems Inventory contained in Appendix I of the DAPR notes the software versions used on each computer. During the early stages of data cleaning and analysis, the survey was sent to AHB to be worked on. Data cleaning and feature management was was performed and the survey was returned to the field unit for additional cleaning and report writing. AHB utilized CARIS HIPS/SIPS version 8.1.10 in their processing. H12509_MB_50cm_MLLWCUBE500.5732.08NOAA_0.5mObject DetectionH12509_MB_50cm_MLLW_FinalCUBE500.4722NOAA_0.5mObject DetectionH12509_MB_1m_MLLWCUBE10.6730.46NOAA_1mObject DetectionH12509_MB_1m_MLLW_FinalCUBE10.4730.46NOAA_1mObject DetectionH12509_MB_4m_MLLWCUBE40.7430.37NOAA_4mMBES TracklineSBES Set Line SpacingH12509_MB_4m_MLLW_FinalCUBE40.4730.37NOAA_4mMBES TracklineSBES Set Line SpacingH12509_1m_100SSS Mosaic1N/A100% SSSH12509_1m_200SSS Mosaic1N/A200% SSSSome areas in the northern part of the sheet, near the shoreline were acquired to Object Detection standards where it was too shallow or hazardous to tow the side scan. See figures below for more details. A 50 centimeter BASE surface encompassing only the northern portion of the sheet has been submitted to cover these near shore Object Detection areas. Density statistics were calculated for this BASE surface and out of 40,347,251 nodes, 99.24% contain 5 or more soundings. Additionally, a 1 meter BASE surface that encompasses the entire survey area has been submitted to enable more detailed analysis of the sea floor during branch review and cartographic compilation. Finally, the required 4 meter BASE surface is submitted for the entire survey to supplement the corresponding 200% SSS data. All submitted surfaces meet density and Order 1a standards.Northwestern survey area, light blue area is covered by 200% SSS, green areas covered by Object Detection MBES.SupportFiles\Western_ObjectDetectionAreas.bmpNortheastern survey area, light blue area is covered by 200% SSS, green areas covered by Object Detection MBES.SupportFiles\Eastern_ObjectDetectionAreas.bmpNo field installed HVCR equipment was utilized for this survey. Therefore, per section 5.1.2.3 of the FPM, no Horizontal and Vertical Control Report has been generated for Survey H12509.Mean Lower Low WaterTCARINew London8461490New Haven84657058461490.tidFinal Approved8465705.tidFinal ApprovedB370NRT52014.tcFinal2014-11-182014-11-19CO-OPS accepted the preliminary TCARI grid as the final grid for survey H12509. Verified tides were downloaded and applied to the bathymetry using the Pydro Fetch Tides tool. North American Datum of 1983 (NAD83)Universal Transverse Mercator(UTM) - Zone 18NMoriches, NY 293 kHzMoriches, NY 293 kHzH12509 was compared to affected RNC and ENC products by creating a high density sounding layer in CARIS BathyDataBase and comparing charted water depths with surveyed soundings.12374216220000152014-122016-01-232016-01-23The western half of H12509 is covered by raster 12374 and surveyed soundings generally agreed with charted depths to within 2 feet. In the northwestern portion of the sheet near Duck Island, some areas of larger disagreement exist and significant contour alterations will be needed. See the figure below for further description. Additionally, DtoNs were discovered and submitted. All changes have been applied to the chart. See DtoN report #3 for more information. Showing areas SE and SW of Duck Island where significant contour changes will be required.SupportFiles\ContoursSoundings_DuckIsland.bmp12375216120000222010-102016-01-232016-01-23The eastern half of H12509 is covered by raster 12374, aside from the very southern portion of the sheet, which is covered by raster 12372. Surveyed soundings generally agreed with charted depths to within 2 feet, aside from some notable exceptions which were determined to be DtoNs. These DtoNs have been applied to the chart and are discussed in DtoN reports #1 and #2. 12372217540000362013-082016-01-232016-01-23Only the deeper, southeastern portion of H12509 is covered by raster 12372 and surveyed soundings agreed within about 4 feet of charted depths. Charted 74 foot depths surrounded by surveyed 75 to 78 foot soundings.SupportFiles\Raster12372_Comparison.bmpUS5CN16M20000122015-09-232015-09-23falseThe ENC US5CN16M matches exactly with raster chart 12374, so all comparisons to this survey are covered in the raster section above. US5CN20M40000132014-09-232014-09-23falseThe ENC US5CN16M matches exactly with raster chart 12372, so all comparisons to this survey are covered in the raster section above. US5CN30M20000132015-09-092015-09-09falseThe ENC US5CN16M matches exactly with raster chart 12375, so all comparisons to this survey are covered in the raster section above. No AWOIS items were assigned for this survey.No Maritime Boundary Points were assigned for this survey. 150 meters to the SSW of Duck Island is a charted PA wreck. MBES coverage was acquired over the majority of the charted feature and no evidence of a wreck exists. Due to proximity to the shoreline, the vessel could not safely be maneuvered over the entirety of the charted feature. The field unit recommends removing the charted position approximate wreck from the chart. Overview of the PA wreck in relation to MBES coverage. 50 cm BASE surface shown.SupportFiles\PAWreckOverview.bmpPer the HSSD Final Feature File requirements, only features which cannot be portrayed in in a simple depth grid are required to be included in the FFF. This survey area contains numerous uncharted rocks and rocky shoals that meet the HSSD criteria for significant features, however, no natural features, including significant rocks and rocky shoals, were included in the Final Features File, as they are adequately represented in the depth grids. Any uncharted feature considered to be dangerous to surface navigation was submitted as a DtoN. Every significant feature was carefully reviewed to ensure that it was adequately developed, and that its least depth was accurately represented in the BASE surface. However, only features appearing to be man-made obstructions, or those which were determined to be DtoNs, were recommended for charting, and included in the Final Features File. 3H12509 DTON Report 12014-08-14H12509 DTON Report 22014-10-02H12509 DtoN Report 32015-08-27Danger to Navigation Reports are included in Appendix III of this report. At the time of this report's submission, all DtoNs have been added to the affected charts. 23 individual features are included in the Final Feature File with the special feature type set to "DTON."DTON reports are appended. Note that final processing of data has resulted in minor changes to depths to some of the features and soundings reported, one foot in some cases. It should also be noted that some of the DTONs initially reported as rocks were later classified and compiled as soundings which is more appropriate in the context of the complete update to the chart. Several shoal features were identified and submitted as DtoNs during processing of this survey. Refer to the DtoN section for more information. 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.A total of 21 bottom samples were collected and their results can be found in the Final Feature .hob file. Overall, most of the area consisted of a sandy bottom type, which supports the evidence of sand waves found in MBES data. Additionally, some areas of mud were discovered.One shoreline feature was assigned and is discussed in section No prior survey comparisons exist for this survey.All ATONS were observed to be on station and serving the intended purpose.No overhead features exist for this survey.No submarine features exist for this survey.No ferry routes or terminals exist for this survey.No platforms exist for this survey.Sand waves were observed in a significant portion of the survey, particularly around Long Sand Shoal. A sand wave area object was created in CARIS BathyDataBase and is included in the Final Feature File.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.Andrew R. ClosNRT 5 Team Lead2016-03-14