U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9447854 PUBLICATION DATE: 12/28/2005
Name: BUSH POINT WHIDBEY ISLAND
WA
NOAA Chart: 18471 Latitude: 48° 2.0' N ( 48.03330)
USGS Quad: FREELAND Longitude: 122° 36.4' W (-122.60700)
To reach the tidal bench marks at Bush Point, Whidbey Island, Admiralty Inlet,
travel 6.4 km (4.0 mi) NW along the east shoreline of the inlet from Austin.
The bench marks are located near the Admirality Inn. The tide gage and staff
were lcoated on the pier at the Admirality Inn.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: TIDAL BM 1 1976
DESIGNATION: 944 7854 TIDAL BM 1
MONUMENTATION: Tidal Station disk VM#: 9222
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 48° 2.0' N ( 48.03330) LONGITUDE: 122° 36.4' W (-122.60700)
The primary bench mark is a disk set flush into the concrete bulkhead of
Admiralty Inn Pier, at the SW end of the pier, and east of bench mark TIDAL BM 2
1976.
BENCH MARK STAMPING: TIDAL BM 2 1976
DESIGNATION: 944 7854 TIDAL BM 2
MONUMENTATION: Tidal Station disk VM#: 9223
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 48° 2.0' N ( 48.03330) LONGITUDE: 122° 36.4' W (-122.60700)
The bench mark is a disk set flush at the NW corner of the bulkhead of Admiralty
Inn Pier, NW of the NW corner of the building, and west of bench mark TIDAL BM 1
1976.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9447854 PUBLICATION DATE: 12/28/2005
Name: BUSH POINT WHIDBEY ISLAND
WA
NOAA Chart: 18471 Latitude: 48° 2.0' N ( 48.03330)
USGS Quad: FREELAND Longitude: 122° 36.4' W (-122.60700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL BM 3 1976
DESIGNATION: 944 7854 TIDAL BM 3
MONUMENTATION: Tidal Station disk VM#: 9224
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 48° 2.0' N ( 48.03330) LONGITUDE: 122° 36.4' W (-122.60700)
The bench mark is a disk set flush into the concrete pavement, located near the
Admiralty Inn, near the SW corner of the building, 0.3 m (1 ft) south of the
stairway leading to the upper level bar and dining rooms, and 0.3 (1 ft) west of
a stone wall around a small flower bed.
BENCH MARK STAMPING: TIDAL BM 4 1976
DESIGNATION: 944 7854 TIDAL BM 4
MONUMENTATION: Tidal Station disk VM#: 9225
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete and stone wall OPUS PID:
LATITUDE: 48° 2.0' N ( 48.03330) LONGITUDE: 122° 36.4' W (-122.60700)
The bench mark is a disk set flush at the SE corner of the concrete and rock
wall, located at the Admiralty Inn, near the SE corner of the building, near an
area currently being used as a garage location, and 0.46 m (1.5 ft) above
ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9447854 PUBLICATION DATE: 12/28/2005
Name: BUSH POINT WHIDBEY ISLAND
WA
NOAA Chart: 18471 Latitude: 48° 2.0' N ( 48.03330)
USGS Quad: FREELAND Longitude: 122° 36.4' W (-122.60700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL BM 5 1976
DESIGNATION: 944 7854 TIDAL BM 5
MONUMENTATION: Tidal Station disk VM#: 9226
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 48° 2.0' N ( 48.03330) LONGITUDE: 122° 36.4' W (-122.60700)
The bench mark is a disk set flush into the concrete foundation, located at the
Admiralty Inn, at the SE corner of the building, SE of bench mark TIDAL BM 4
1976, and 5 m (15 ft) north of the SW corner of the old L-shaped building
foundation.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9447854 PUBLICATION DATE: 12/28/2005
Name: BUSH POINT WHIDBEY ISLAND
WA
NOAA Chart: 18471 Latitude: 48° 2.0' N ( 48.03330)
USGS Quad: FREELAND Longitude: 122° 36.4' W (-122.60700)
T I D A L D A T U M S
Tidal datums at BUSH POINT WHIDBEY ISLAND based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: March 1977 - March 1977
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9447130 SEATTLE, PUGET SOUND
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.850
MEAN HIGH WATER MHW = 2.612
MEAN TIDE LEVEL MTL = 1.718
MEAN SEA LEVEL MSL = 1.710
MEAN LOW WATER MLW = 0.824
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
TIDAL BM 1 1976 4.295 1.683
TIDAL BM 2 1976 4.301 1.689
TIDAL BM 3 1976 4.199 1.587
TIDAL BM 4 1976 4.275 1.663
TIDAL BM 5 1976 4.453 1.841
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9447854 PUBLICATION DATE: 12/28/2005
Name: BUSH POINT WHIDBEY ISLAND
WA
NOAA Chart: 18471 Latitude: 48° 2.0' N ( 48.03330)
USGS Quad: FREELAND Longitude: 122° 36.4' W (-122.60700)
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.