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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9445088 PUBLICATION DATE: 07/12/2004
Name: LOFALL
WA
NOAA Chart: 18461 Latitude: 47° 48.9' N ( 47.81500)
USGS Quad: LOFALL Longitude: 122° 39.4' W (-122.65700)
To reach the tidal bench marks from Port Gamble, proceed west on Hood Canal to
the floating bridge, SSW on Highway 3 to Lofall, then turn right and proceed
west on NW Lofall Road, then turn right and proceed north on Lofall Court NW.
The bench marks are located along area between the Newton Skelley residence and
Hood Canal. The tide gage and staff were located on a piling in Hood Canal,
north of the Skelley residence.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: BM 7 1966
DESIGNATION: 944 5088 TIDAL 7
MONUMENTATION: Tidal Station disk VM#: 9034
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 47° 48.9' N ( 47.81500) LONGITUDE: 122° 39.4' W (-122.65700)
The primary bench mark is a disk set in a large 1 m (2 ft) granite boulder at
the edge of a bluff on the property of Mr. Oscar Wall, 31 m (102 ft) north of
the NW corner of the beach house, and 17.53 m (57.5 ft) east of bench mark NO 1
1946.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9445088 PUBLICATION DATE: 07/12/2004
Name: LOFALL
WA
NOAA Chart: 18461 Latitude: 47° 48.9' N ( 47.81500)
USGS Quad: LOFALL Longitude: 122° 39.4' W (-122.65700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 4 1961
DESIGNATION: 944 5088 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 9035
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 47° 48.9' N ( 47.81500) LONGITUDE: 122° 39.4' W (-122.65700)
The bench mark is a disk set along the SE edge of a large concrete slab near the
front door of a beach house owned by Homer Skelley, on the north side of County
Road 4.
BENCH MARK STAMPING: NO 5 1961
DESIGNATION: 944 5088 TIDAL 5
MONUMENTATION: Tidal Station disk VM#: 9036
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete step OPUS PID:
LATITUDE: 47° 48.9' N ( 47.81500) LONGITUDE: 122° 39.4' W (-122.65700)
The bench mark is a disk set in the second step of concrete stairs leading from
the road to the home of Newton Skelley and 11 m (35 ft) SSE of bench mark NO 4
1961.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9445088 PUBLICATION DATE: 07/12/2004
Name: LOFALL
WA
NOAA Chart: 18461 Latitude: 47° 48.9' N ( 47.81500)
USGS Quad: LOFALL Longitude: 122° 39.4' W (-122.65700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 6 1961
DESIGNATION: 944 5088 TIDAL 6
MONUMENTATION: Tidal Station disk VM#: 9037
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 47° 48.9' N ( 47.81500) LONGITUDE: 122° 39.4' W (-122.65700)
The bench mark is a disk set in the NE corner of a concrete slab adjacent to the
NE corner of the Newton Skelley house, at the head of the steps leading to the
basement and 9 m (30 ft) SW of bench mark NO 5 1961.
BENCH MARK STAMPING: 1 1946
DESIGNATION: 944 5088 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 9038
AGENCY: US Coast & Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 47° 48.9' N ( 47.81500) LONGITUDE: 122° 39.4' W (-122.65700)
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9445088 PUBLICATION DATE: 07/12/2004
Name: LOFALL
WA
NOAA Chart: 18461 Latitude: 47° 48.9' N ( 47.81500)
USGS Quad: LOFALL Longitude: 122° 39.4' W (-122.65700)
T I D A L D A T U M S
Tidal datums at LOFALL based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: February 1978 - February 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 = 3.263
MEAN HIGH WATER MHW = 2.991
MEAN TIDE LEVEL MTL = 1.931
MEAN SEA LEVEL MSL = 1.914
MEAN LOW WATER MLW = 0.871
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
BM 7 1966 9.781 6.790
NO 4 1961 6.515 3.524
NO 5 1961 8.982 5.991
NO 6 1961 10.345 7.354
1 1946 6.472 3.481
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9445088 PUBLICATION DATE: 07/12/2004
Name: LOFALL
WA
NOAA Chart: 18461 Latitude: 47° 48.9' N ( 47.81500)
USGS Quad: LOFALL Longitude: 122° 39.4' W (-122.65700)
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.