U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9446281 PUBLICATION DATE: 07/26/2004
Name: ALLYN
WA
NOAA Chart: 18440 Latitude: 47° 23.0' N ( 47.38330)
USGS Quad: BELFAIR Longitude: 122° 49.4' W (-122.82300)
To reach the tidal bench marks from the intersection of State Routes 3 and 302,
proceed south on State Route 3 for 0.2 km (0.1 mi) to the town of Allyn, then
turn left and proceed east on a paved road at the first Episcopal Church to the
County Pier 2 on Case Inlet. The bench marks are along State Route 3 and the
waterfront. The gage and staff were on County Pier 2.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1917 NO 3
DESIGNATION: 944 6281 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 9128
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#: SY0805
SETTING CLASSIFICATION: In a boulder OPUS PID:
LATITUDE: 47° 23.0' N ( 47.38330) LONGITUDE: 122° 49.6' W (-122.82700)
The primary bench mark is a disk set flush in the top of a 0.6 m (2 ft) diameter
boulder, 91 m (300 ft) south of the road leading to the County Pier on the west
side of a dim road, 85 m (280 ft) south of the west end of the County Pier, 52 m
(170 ft) north of the north side of Uhlman Street, 43 m (141 ft) south of a
house, 25 m (81 ft) south of a red brick chimney on the south side of a newer
house, 22 m (72 ft) west of the Shoreline, 0.3 m (1 ft) west of the fence line
at the west side of Gross Street, and set 0.3 m (1 ft) above ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9446281 PUBLICATION DATE: 07/26/2004
Name: ALLYN
WA
NOAA Chart: 18440 Latitude: 47° 23.0' N ( 47.38330)
USGS Quad: BELFAIR Longitude: 122° 49.4' W (-122.82300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1917 NO 1
DESIGNATION: 944 6281 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 9126
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#: SY0804
SETTING CLASSIFICATION: Set in a boulder OPUS PID:
LATITUDE: 47° 23.1' N ( 47.38500) LONGITUDE: 122° 49.7' W (-122.82800)
The bench mark is a disk set flush on the east side of a 1.37 m (4.5 ft)
diameter boulder with a 30 degree slope, 64 m (210 ft) south of a private
residence, 28 m (91 ft) north of the first Episcopal Church, 20 m (65 ft) north
of the centerline of the road leading to the pier, and 9 m (30 ft) east of the
centerline of State Route 3 and 0.6 m (2 ft) above ground level.
BENCH MARK STAMPING: 6281 J 1977
DESIGNATION: 944 6281 J TIDAL
MONUMENTATION: Tidal Station disk VM#: 9131
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 47° 23.0' N ( 47.38330) LONGITUDE: 122° 49.4' W (-122.82300)
The bench mark is a disk set in a drill hole in a concrete retaining wall on the
east end on the shoreward end of the south retaining wall of the Allyn County
pier, 8 m (25 ft) east of the west end of the wall, 0.15 m (0.5 ft) west of the
pier and 0.76 m (2.5 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9446281 PUBLICATION DATE: 07/26/2004
Name: ALLYN
WA
NOAA Chart: 18440 Latitude: 47° 23.0' N ( 47.38330)
USGS Quad: BELFAIR Longitude: 122° 49.4' W (-122.82300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6281 K 1977
DESIGNATION: 944 6281 K TIDAL
MONUMENTATION: Tidal Station disk VM#: 9132
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 47° 23.0' N ( 47.38330) LONGITUDE: 122° 49.4' W (-122.82300)
The bench mark is a disk set in a drill hole in a concrete retaining wall on the
west end of the shoreward end of the south retaining wall of the County pier, 8
m (25 ft) west of the pier, and 0.15 m (0.5 ft) east of the west end of the
concrete wall and 0.76 m (2.5 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9446281 PUBLICATION DATE: 07/26/2004
Name: ALLYN
WA
NOAA Chart: 18440 Latitude: 47° 23.0' N ( 47.38330)
USGS Quad: BELFAIR Longitude: 122° 49.4' W (-122.82300)
T I D A L D A T U M S
Tidal datums at ALLYN based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: February 1978 - March 1978
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 = 4.334
MEAN HIGH WATER MHW = 4.050
MEAN SEA LEVEL MSL = 2.492
MEAN TIDE LEVEL MTL = 2.490
MEAN LOW WATER MLW = 0.929
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1917 NO 3 6.108 2.058
1917 NO 1 10.319 6.269
6281 J 1977 5.828 1.778
6281 K 1977 5.805 1.755
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9446281 PUBLICATION DATE: 07/26/2004
Name: ALLYN
WA
NOAA Chart: 18440 Latitude: 47° 23.0' N ( 47.38330)
USGS Quad: BELFAIR Longitude: 122° 49.4' W (-122.82300)
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.