U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 4 PUBLICATION DATE: 09/27/2001 Station ID: 9456992 SUPERCEDED DATE: 04/21/2003 Name: TAKLI ISLAND ALASKA NOAA Chart: 16576 Latitude: 58° 3.8' N USGS Quad: Mount Katmai (A-2) Longitude: 154° 28.6' W To reach the tidal bench marks proceed by boat to Takli Island, which is located at the entrance to Amalik Bay in Shelikof Straits. The bench marks are located at the north end of a prominent peninsula on the NE end of the Island. The tide gage was mounted on the rock cliff with the orifice and tubing extending 15.24 m (50.0 ft) offshore. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: TIDAL 1 DESIGNATION: 945 6992 TIDAL 1 MONUMENTATION: Tidal Station disk VM#: 9642 AGENCY: National Ocean Survey (NOS) PID: SETTING CLASSIFICATION: Rock outcrop The primary bench mark is a disk set flush in a rounded 3 m (10 ft) diameter rock on the north end of a prominent peninsula on the NE end of the island, 21 m (70 ft) NW of a rock cliff, NE (44 degrees per magnetic compass) of the eastern cliff of a prominent wedge shaped island, and is submerged at high water. BENCH MARK STAMPING: TIDAL 2 DESIGNATION: 945 6992 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 9643 AGENCY: National Ocean Survey (NOS) PID: SETTING CLASSIFICATION: Rock outcrop The bench mark is a disk set flush in a rounded 2 m (6 ft) diameter rock on the north end of a promonent peninsula on the NE end of the island, 30 m (97 ft) SSE (152 degrees per magnetic compass) of bench mark Tidal 1, 5 m (15 ft) from the base of a rock cliff, and is submerged at high water.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 4 PUBLICATION DATE: 09/27/2001 Station ID: 9456992 SUPERCEDED DATE: 04/21/2003 Name: TAKLI ISLAND ALASKA NOAA Chart: 16576 Latitude: 58° 3.8' N USGS Quad: Mount Katmai (A-2) Longitude: 154° 28.6' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: TIDAL 3 DESIGNATION: 945 6992 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 9644 AGENCY: National Ocean Survey (NOS) PID: SETTING CLASSIFICATION: Rock outcrop The bench mark is a disk set flush in a rounded 2 m (8 ft) diameter rock on the north end of a prominent peninsula on the NE end of the island, 25 m (83 ft) SSE (160 degrees per magnetic compass) of bench mark Tidal 2, 6 m (20 ft) west of the base of a rock cliff, and is submerged at high water. BENCH MARK STAMPING: TIDAL 4 DESIGNATION: 945 6992 TIDAL 4 MONUMENTATION: Tidal Station disk VM#: 9645 AGENCY: National Ocean Survey (NOS) PID: SETTING CLASSIFICATION: Rock outcrop The bench mark is a disk set flush in a 2 m (6 ft) diameter diamond shaped rock on the north end of a prominent peninsula on the NE end of the island, 54 m (176 ft) SE (140 degrees per magnetic compass) of bench mark Tidal 3, 8 m (25 ft) west of the base of a rock cliff, and is submerged at high water. BENCH MARK STAMPING: TIDAL 5 DESIGNATION: 945 6992 TIDAL 5 MONUMENTATION: Tidal Station disk VM#: 9646 AGENCY: National Ocean Survey (NOS) PID: SETTING CLASSIFICATION: Rock outcrop The bench mark is a disk set flush in a 1 m (2 ft) square flat topped rock on the north end of a prominent peninsula on the NE end of the island, 34 m (110 ft) SE (130 degrees per magnetic compass) from bench mark Tidal 4, and is at the base of a rock cliff.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 4 PUBLICATION DATE: 09/27/2001 Station ID: 9456992 SUPERCEDED DATE: 04/21/2003 Name: TAKLI ISLAND ALASKA NOAA Chart: 16576 Latitude: 58° 3.8' N USGS Quad: Mount Katmai (A-2) Longitude: 154° 28.6' W T I D A L D A T U M S Tidal datums at TAKLI ISLAND based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: June 1980 - August 1980 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 9459450 SAND POINT, POPOF ISLAND Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 4.133 MEAN HIGH WATER MHW = 3.852 MEAN TIDE LEVEL MTL = 2.181 MEAN LOW WATER MLW = 0.510 MEAN LOWER LOW WATER MLLW = 0.000 Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW TIDAL 1 2.616 -1.236 TIDAL 2 3.357 -0.495 TIDAL 3 2.592 -1.260 TIDAL 4 2.545 -1.307 TIDAL 5 4.505 0.653
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 4 PUBLICATION DATE: 09/27/2001 Station ID: 9456992 SUPERCEDED DATE: 04/21/2003 Name: TAKLI ISLAND ALASKA NOAA Chart: 16576 Latitude: 58° 3.8' N USGS Quad: Mount Katmai (A-2) Longitude: 154° 28.6' W 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 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.