U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9452434 PUBLICATION DATE: 06/21/2018 Name: TAIYASANKA HARBOR AK NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170) USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800) To reach the tidal bench marks, go to the entrance of Tiayasanka Harbor on the NW shore which can be identified by a prominent rock outcropping made largely of iron-streaked granite rock outcrop positioned between two separate 75 m (246 ft) long sections of boulder-filled beach. The bench marks are located along the beach in the general vicinity. The tide gauge was placed behind a large boulder, 25 m (82 ft) inland of the water's edge, and 8 m (26 ft) above the apparent high water line. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 2434 C 1998 DESIGNATION: 945 2434 C MONUMENTATION: Tidal Station disk VM#: 14046 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800) The primary bench mark is a disk set on a large flat section 5 m x 3 m (15 ft x 10 ft) of granite bedrock located on the front section of the outcropping, 46 m (151 ft) SW (220 degrees magnetic) from bench mark 2434 B 1998, and 4 m (12 ft) above the apparent high water line. Note: There is not a direct line of sight between bench marks 2434 B 1998 and 2434 C 1998 due to the curvature of the outcropping.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9452434 PUBLICATION DATE: 06/21/2018 Name: TAIYASANKA HARBOR AK NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170) USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2434 A 1998 DESIGNATION: 945 2434 A MONUMENTATION: Tidal Station disk VM#: 14044 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800) The bench mark is a disk set at approximately knee level at the lower end of a very large (automobile-sized or larger), distinctive, polymorphous, red-coloured rock located on the far eastern edge of the beach section directly to the east of the outcropping, and is roughly 2 m (7 ft) above the apparent high water line. Note: The bench mark may become covered during periods of extremely high tide. BENCH MARK STAMPING: 2434 B 1998 DESIGNATION: 945 2434 B MONUMENTATION: Tidal Station disk VM#: 14045 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800) The bench mark is a disk set in gray colored granite bedrock, roughly two-third of the way down from the high point of the outcropping which overlooks a portion of the east beach section, located at the junction of the outcropping and the beach section directly to the east, 51 m (167 ft) SW (200 degrees magnetic) from bench mark 2434 A 1998.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9452434 PUBLICATION DATE: 06/21/2018 Name: TAIYASANKA HARBOR AK NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170) USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2434 D 1998 DESIGNATION: 945 2434 D MONUMENTATION: Tidal Station disk VM#: 14047 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Granite bedrock OPUS PID: LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800) The bench mark is a disk set on a narrow flat section of the granite bedrock on the western portion of the outcropping overlooking the boulder-filled beach to the west, near the junction of the outcropping and the beach section directly to the west, 43 m (141 ft) NW (300 degrees magnetic) from bench mark 2434 C 1998. Note: There is not a direct line of sight between bench marks 2434 C 1998 and 2434 D 1998 due to the curvature of the outcropping. BENCH MARK STAMPING: 2434 E 1998 DESIGNATION: 945 2434 E MONUMENTATION: Tidal Station disk VM#: 14048 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Granite bedrock OPUS PID: LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800) The bench mark is a disk set in the granite bedrock on the western portion of the outcropping overlooking the boulder-filled beach to the west, near the junction of the outcropping and the beach section directly to the west, 43 m (141 ft) NW (295 degrees magnetic) from bench mark 2434 D 1998, in a direct line of sight which follows the curvature of the outcropping.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9452434 PUBLICATION DATE: 06/21/2018 Name: TAIYASANKA HARBOR AK NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170) USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800) T I D A L D A T U M S Tidal datums at TAIYASANKA HARBOR based on: LENGTH OF SERIES: 30 DAYS TIME PERIOD: Apr 28 1998 - May 27 1998 TIDAL EPOCH: 2012-2016 CONTROL TIDE STATION: 9452400 SKAGWAY, TAIYA INLET Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 5.103 MEAN HIGH WATER MHW = 4.810 MEAN SEA LEVEL MSL = 2.706 MEAN TIDE LEVEL MTL = 2.651 MEAN LOW WATER MLW = 0.493 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 2434 C 1998 8.786 3.977 2434 A 1998 7.194 2.384 2434 B 1998 8.379 3.570 2434 D 1998 8.481 3.671 2434 E 1998 9.148 4.339
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9452434 PUBLICATION DATE: 06/21/2018 Name: TAIYASANKA HARBOR AK NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170) USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800) 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.