U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9450463 PUBLICATION DATE: 04/23/2012 Name: TROCADERO BAY AK NOAA Chart: 17405 Latitude: 55° 21.1' N ( 55.35167) USGS Quad: CRAIG (B-3) Longitude: 132° 56.3' W (-132.93806) To reach the bench marks from Craig, AK via boat, proceed SSE for approximately 8.5 km (4.5 nm) through Bucarelli Bay, turn ESE and proceed 3.3 km (1.8 nm) upon reaching Culebrina Island through Trocadero Bay, turn SSE and proceed 4.0 km (2.2 nm) through Trocadero Bay, turn E and proceed 2.9 km (1.6 nm) through Trocadero Bay, turn ESE and proceed 2.4 km (1.3 nm) in Trocadero Bay. Additionally, the tide gauge site is located on a small island 3.2 km (1.7 nm) E of Pt St Sebastian. The benchmarks are located on the SW end of the island, following the island shoreline, close to the treeline. The tide staff was located on the south end of the island, along with the tide gauge. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 9450463-C 2009 DESIGNATION: 945 0463 C MONUMENTATION: Tidal Station disk VM#: 19192 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID#: BBBJ74 LATITUDE: 55° 21.1' N ( 55.35186) LONGITUDE: 132° 56.3' W (-132.93844) The primary bench mark is set flush in bedrock 0.40 km (0.22 nm) from the prominent point of land ESE of the island, 200.00 m (656.17 ft) from bench mark 945 0463 B, 90.00 m (295.3 ft) from the southern treeline at the east end of the island, 5.00 m (16.4 ft) from the treeline, and 1.00 m (3.3 ft) above mean high water.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9450463 PUBLICATION DATE: 04/23/2012 Name: TROCADERO BAY AK NOAA Chart: 17405 Latitude: 55° 21.1' N ( 55.35167) USGS Quad: CRAIG (B-3) Longitude: 132° 56.3' W (-132.93806) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9450463-A 2009 DESIGNATION: 945 0463 A MONUMENTATION: Tidal Station disk VM#: 19189 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 55° 21.1' N ( 55.35197) LONGITUDE: 132° 56.3' W (-132.93892) The bench mark is set flush in bedrock 400.00 m (1,312.3 ft) from south shore of the island W of the tide gauge site, 240.00 m (787.40 ft) from the second point of land east of Point Saint Sebastian, 70.00 m (229.66 ft) from bench mark 945 0463 B, 15.00 m (49.2 ft) from the treeline, and 1.20 m (3.9 ft) above mean high water. BENCH MARK STAMPING: 9450463-B 2009 DESIGNATION: 945 0463 B MONUMENTATION: Tidal Station disk VM#: 19191 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 55° 21.1' N ( 55.35181) LONGITUDE: 132° 56.3' W (-132.93853) The bench mark is set flush in bedrock at the treeline 470.00 m (1,542.0 ft) from the south shore of the island west of the tide gauge site, 260.00 m (853.0 ft) from the second point of land east of Point Saint Sebastian, 10.00 m (32.8 ft) from bench mark 945 0463 C, and 1.00 m (3.3 ft) above mean high water.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9450463 PUBLICATION DATE: 04/23/2012 Name: TROCADERO BAY AK NOAA Chart: 17405 Latitude: 55° 21.1' N ( 55.35167) USGS Quad: CRAIG (B-3) Longitude: 132° 56.3' W (-132.93806) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9450463-D 2009 DESIGNATION: 945 0463 D MONUMENTATION: Tidal Station disk VM#: 19193 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 55° 21.1' N ( 55.35194) LONGITUDE: 132° 56.3' W (-132.93822) The bench mark is set flush in bedrock 145.00 m (475.72 ft) from the prominent point SE of the tide gauge site, 120.00 m (393.70 ft) from the SE shoreline of the large island north of the tide gauge site, 20.00 m (65.62 ft) from bench mark 945 06463 C, 1.60 m (5.25 ft) above mean high water, and 1.00 m (3.3 ft) from treeline. BENCH MARK STAMPING: 9450463-E 2009 DESIGNATION: 945 0463 E MONUMENTATION: Tidal Station disk VM#: 19196 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 55° 21.1' N ( 55.35219) LONGITUDE: 132° 56.3' W (-132.93817) The bench mark is set flush in bedrock at the treeline 560.00 m (1,837.27 ft) from the southernmost small island east of the tide gauge site, 115.00 m (377.30 ft) from the SE shoreline of the large island north of the tide gauge site, 50.00 m (164.04 ft) from bench mark 945 0463 D, and 1.50 m (4.9 ft) above mean high water.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9450463 PUBLICATION DATE: 04/23/2012 Name: TROCADERO BAY AK NOAA Chart: 17405 Latitude: 55° 21.1' N ( 55.35167) USGS Quad: CRAIG (B-3) Longitude: 132° 56.3' W (-132.93806) T I D A L D A T U M S Tidal datums at TROCADERO BAY based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: May 2009 - May 2009 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9451600 SITKA, BARONOF ISLAND, SITKA SOUND Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 3.073 MEAN HIGH WATER MHW = 2.825 MEAN TIDE LEVEL MTL = 1.619 MEAN SEA LEVEL MSL = 1.612 MEAN LOW WATER MLW = 0.413 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 9450463-C 2009 3.120 0.295 9450463-A 2009 3.279 0.454 9450463-B 2009 3.049 0.224 9450463-D 2009 3.756 0.931 9450463-E 2009 3.671 0.846
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9450463 PUBLICATION DATE: 04/23/2012 Name: TROCADERO BAY AK NOAA Chart: 17405 Latitude: 55° 21.1' N ( 55.35167) USGS Quad: CRAIG (B-3) Longitude: 132° 56.3' W (-132.93806) D E F I N I T I O N S Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal Datum Epoch. It pertains to local mean sea level and should not be confused with the fixed datums of North American Vertical Datum of 1988 (NAVD88). NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum constraint adjustment of Canadian/Mexican/United States leveling observations. Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as the single initial constraint. NAVD88 replaces NGVD29 as the national standard geodetic reference for heights. Bench mark elevations relative to NAVD88 are available from NGS through the World Wide Web at National Geodetic Survey. NGVD29 is a fixed datum adopted as a national standard geodetic reference for heights but is now considered superseded. NGVD29 is sometimes referred to as Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological Survey Topographic Quads. NGVD29 was originally derived from a general adjustment of the first-order leveling networks of the U.S. and Canada after holding mean sea level observed at 26 long term tide stations as fixed. Numerous local and wide-spread adjustments have been made since establishment in 1929. Bench mark elevations relative to NGVD29 are available from the National Geodetic Survey (NGS) data base via the World Wide Web at National Geodetic Survey. NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to local MSL and other tidal datums may not be consistent from one location to another. The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique identifiers for bench marks in the tidal and geodetic databases, respectively. Each bench mark in either database has a single, unique VM# and/or PID# assigned. Where both VM# and PID# are indicated, both tidal and geodetic elevations are available for the bench mark listed. The NGS's Integrated Data Base (IDB PID) provides geodetic datum based on traditionally leveled and bluebooked ties to the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/. The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/. The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred to MLLW only when two or more of the bench marks listed have NAVD88 elevations. The NAVD88 elevation relationship shown in the table is derived from an average of several bench mark elevations relative to tide station datum. As a result of this averaging, NAVD88 bench mark elevations computed indirectly from the tidal datums elevation table may differ slightly from NAVD88 elevations listed for each bench mark in the NGS database.