U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9452249 PUBLICATION DATE: 06/21/2018 Name: YOUNG BAY AK NOAA Chart: 17315 Latitude: 58° 11.0' N ( 58.18330) USGS Quad: JUNEAU (A-2) Longitude: 134° 35.2' W (-134.58700) To reach tidal bench marks, from Juneau proceed to eastern Young Bay and then proceed south to Admiralty Cove to the northeastern end of the island at Latitude 58 11.04' N, Longitude 134 35.22' W. The island is connected to Admiralty Island at low water. The tide gage and bench marks were located along the beach in the general vicinity. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 2249 A 1997 DESIGNATION: 945 2249 A MONUMENTATION: Tidal Station disk VM#: 13665 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 58° 11.0' N ( 58.18400) LONGITUDE: 134° 35.2' W (-134.58700) The primary bench mark is a disk set on a rocky outcrop of bedrock, 30 m (98 ft) NW (330 degrees magnetic) from bench mark 2249 B 1997, and 2 m (5 ft) above the apparent high water line. BENCH MARK STAMPING: 2249 B 1997 DESIGNATION: 945 2249 B MONUMENTATION: Tidal Station disk VM#: 13666 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 58° 11.0' N ( 58.18400) LONGITUDE: 134° 35.2' W (-134.58700) The bench mark is a disk set on a rocky outcrop of bedrock, 30 m (98 ft) SE (150 degrees magnetic) from bench mark 2249 A 1997, 35 m (115 ft) NE (010 degrees magnetic) from bench mark 2249 C 1997, and 2 m (5 ft) above the apparent high water line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9452249 PUBLICATION DATE: 06/21/2018 Name: YOUNG BAY AK NOAA Chart: 17315 Latitude: 58° 11.0' N ( 58.18330) USGS Quad: JUNEAU (A-2) Longitude: 134° 35.2' W (-134.58700) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2249 C 1997 DESIGNATION: 945 2249 C MONUMENTATION: Tidal Station disk VM#: 13667 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Granite boulder OPUS PID: LATITUDE: 58° 11.0' N ( 58.18400) LONGITUDE: 134° 35.2' W (-134.58700) The bench mark is a disk set on a granite boulder situated at the treeline, 35 m (115 ft) SW (190 degrees magnetic) from bench mark 2249 B 1997, 55 m (180 ft) NW (285 degrees magnetic) from bench mark 2249 D 1997, and 2 m (5 ft) above the apparent high water line. BENCH MARK STAMPING: 2249 D 1997 DESIGNATION: 945 2249 D MONUMENTATION: Tidal Station disk VM#: 13670 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 58° 11.0' N ( 58.18400) LONGITUDE: 134° 35.2' W (-134.58700) The bench mark is a disk set in bedrock, 55 m (180 ft) SE (105 degrees magnetic) from bench mark 2249 C 1997, 50 m (164 ft) NW (275 degrees magnetic) from bench mark 2249 E 1997, and 2 m (5 ft) above the apparent high water line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9452249 PUBLICATION DATE: 06/21/2018 Name: YOUNG BAY AK NOAA Chart: 17315 Latitude: 58° 11.0' N ( 58.18330) USGS Quad: JUNEAU (A-2) Longitude: 134° 35.2' W (-134.58700) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2249 E 1997 DESIGNATION: 945 2249 E MONUMENTATION: Tidal Station disk VM#: 13672 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Bedrock OPUS PID: LATITUDE: 58° 11.0' N ( 58.18400) LONGITUDE: 134° 35.2' W (-134.58700) The bench mark is a disk set in bedrock protruding from a gently sloping rocky beach, 50 m (164 ft) SE (95 degrees magnetic) from bench mark 2249 D 1997, and 2 m (5 ft) above the apparent high water line.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9452249 PUBLICATION DATE: 06/21/2018 Name: YOUNG BAY AK NOAA Chart: 17315 Latitude: 58° 11.0' N ( 58.18330) USGS Quad: JUNEAU (A-2) Longitude: 134° 35.2' W (-134.58700) T I D A L D A T U M S Tidal datums at YOUNG BAY based on: LENGTH OF SERIES: 30 DAYS TIME PERIOD: Apr 1 1997 - Apr 30 1997 TIDAL EPOCH: 2012-2016 CONTROL TIDE STATION: 9452210 JUNEAU, GASTINEAU CHANNEL, STEPHENS PASS Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 4.996 MEAN HIGH WATER MHW = 4.689 MEAN SEA LEVEL MSL = 2.627 MEAN TIDE LEVEL MTL = 2.588 MEAN LOW WATER MLW = 0.486 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 2249 A 1997 7.185 2.496 2249 B 1997 7.014 2.325 2249 C 1997 7.113 2.424 2249 D 1997 5.384 0.695 2249 E 1997 6.210 1.521
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9452249 PUBLICATION DATE: 06/21/2018 Name: YOUNG BAY AK NOAA Chart: 17315 Latitude: 58° 11.0' N ( 58.18330) USGS Quad: JUNEAU (A-2) Longitude: 134° 35.2' W (-134.58700) 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.