NOAA 0 30 330 0 30 60 330 60 300 90 300 90 270 120 270 240 150 240 120 180 210 210 150 180 Office of Coast Survey Hydrographic Surveys Division Hydrographic Survey Specifications and Deliverables April 2021 Office of Coast Survey National Oceanic and Atmospheric Administration Contents 1 Introduction ......................................................................................................................................1 1.1 Change Management ............................................................................................................................................. 2 1.2 Changes from May 2020 ........................................................................................................................................ 2 1.3 Definitions ............................................................................................................................................................... 3 1.3.1 Hydrographer ................................................................................................................................................. 3 1.3.2 Navigable Area Survey .................................................................................................................................. 4 1.4 Pre-Survey Assessment ......................................................................................................................................... 5 1.5 Environmental Compliance .................................................................................................................................. 5 1.6 Dangers to Navigation ........................................................................................................................................... 6 1.6.1 Definition ......................................................................................................................................................... 6 1.6.2 DTON Reporting to Non-NOAA Source Authorities ............................................................................... 7 1.6.2.1 Federal USACE Channels ...................................................................................................................... 7 1.6.2.2 Aids to Navigation (USCG) .................................................................................................................... 7 1.6.2.3 Bridge Heights (USCG) .......................................................................................................................... 8 1.6.3 DTON Reporting to NOAA .......................................................................................................................... 8 1.6.4 Charted Feature Remove Request (Anti-DTON) ....................................................................................... 9 1.7 Seep and Pipeline Reporting ................................................................................................................................. 9 1.7.1 Seep and Pipeline Reporting to BSEE .......................................................................................................... 9 1.7.2 Dangerous Pipeline Reporting to NOAA .................................................................................................. 10 1.7.3 Non-Dangerous Pipeline Reporting to NOAA ......................................................................................... 10 2 Datums ............................................................................................................................................11 2.1 Time ....................................................................................................................................................................... 11 2.2 Horizontal Datum ................................................................................................................................................ 11 2.3 Vertical Datum ...................................................................................................................................................... 11 2.3.1 Charted Soundings and Heights ................................................................................................................. 11 2.3.2 Survey Platform Positioning (Control) ...................................................................................................... 11 3 Hydrographic Positioning .............................................................................................................13 3.1 The National Spatial Reference System (NSRS) ............................................................................................... 13 3.1.1 GNSS Terminology ...................................................................................................................................... 13 3.2 Horizontal Control ............................................................................................................................................... 14 3.3 Vertical Control .................................................................................................................................................... 14 3.4 Ellipsoid Referenced Survey (ERS) Control ..................................................................................................... 15 3.4.1 ERS Planning and Operational Requirement .......................................................................................... 15 3.4.2 ERS GNSS Infrastructure ........................................................................................................................... 15 3.5 ERS Datum Transformation Requirements ...................................................................................................... 16 3.5.1 VDatum SEP Models .................................................................................................................................. 16 3.5.2 Ellipsoid Referenced Tidal Datum Model (ERTDM) and Alternate SEP Models ............................. 16 3.5.2.1 Ellipsoid Referenced Zoned Tides (ERZT) .................................................................................... 16 3.5.2.2 Constant Value Separation Model ................................................................................................... 17 3.5.3 ERS SEP QC Requirements ....................................................................................................................... 17 4 Tides and Water Levels Requirements .........................................................................................18 4.1 General Project Requirements and Scope ......................................................................................................... 19 4.1.1 Scope ............................................................................................................................................................. 19 4.1.2 Objectives ..................................................................................................................................................... 19 4.1.3 Planning and Preliminary Tidal Modeling .............................................................................................. 19 4.1.4 NOS Control Stations and Data Quality Monitoring ............................................................................. 20 4.1.5 General Data and Reference Datum Requirements ................................................................................ 20 4.1.6 Error Budget Considerations ..................................................................................................................... 21 4.2 Data Collection and Field Work ......................................................................................................................... 23 4.2.1 Water Level Station Requirements ............................................................................................................ 23 4.2.2 Water Level Sensors ..................................................................................................................................... 24 4.2.2.1 Bottom Mounted Pressure Gauge (BMPG) ..................................................................................... 27 4.2.2.2 GNSS Tide Buoys .................................................................................................................................. 28 4.2.3 Station Installation, Operation, and Removal ......................................................................................... 29 4.2.4 Tide Staff ...................................................................................................................................................... 30 4.2.5 Bench Marks ................................................................................................................................................. 33 4.2.5.1 Type of Bench Marks ............................................................................................................................. 33 4.2.5.2 Digital Photographs of the Station and Bench Marks ....................................................................... 34 4.2.5.3 Obtaining and Recording of Positions of Station, Data Collection Platform, Sensors, and Bench Marks Using a Handheld GPS Receiver .......................................................................................................... 34 4.2.6 Leveling 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