U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9440422 PUBLICATION DATE: 09/07/2004
Name: LONGVIEW, COLUMBIA RIVER
WASHINGTON
NOAA Chart: 18524 Latitude: 46° 6.5' N
USGS Quad: RAINIER Longitude: 122° 57.4' W
To reach the tidal bench marks from the Lewis and Clark Bridge over the Columbia
River (Highway 433) in Longview, turn west at the north bridge approach and
follow sign to Port Docks. Drive straight toward the river along the east side
of the bridge structure until you reach the Port of Longview office. Veer left
and drive straight to the water front. Turn left on the wharf and drive about
300 m (1000 ft) up the river to a grain conveyor at Berth 4. The tidal bench
mark are located located in the vicinity. The tide station is a 6 x 6
fiberglass house beside the Pilot's Office, directly beneath the conveyor. The
staff is located on a piling just upstream of the tide house.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 5 1949
DESIGNATION: 944 0422 TIDAL 5
MONUMENTATION: Tidal Station disk VM#: 16639
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: SC1112
SETTING CLASSIFICATION: Parking lot
The bench mark is a disk set in the parking area on the NE side of the Port of
Longview Administration Building, 49.90 m (163.7 ft) SE of bench mark 6 1951,
34.17 m (112.1 ft) west of a yellow fire hydrant protected by four yellow metal
guard posts, 31.91 m (104.7 ft) south of the western corner of warehouse
building No. 9, 22.86 m (75.0 ft) SE of the flag pole on the north side of the
Administration Building, and set 0.15 m (0.5 ft) below ground level under a
protective square steel plate flush with the pavement.
BENCH MARK STAMPING: 6 1951
DESIGNATION: 944 0422 TIDAL 6
MONUMENTATION: Tidal Station disk VM#: 16640
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: SC1111
SETTING CLASSIFICATION: Concrete pier
The bench mark is a disk set on the SE corner of the NE leg of fourth dry land
pier of Longview Bridge, 42.67 m (140.0 ft) SW of the SW corner of a warehouse,
27.43 m (90.0 ft) NW of flag staff, 4.57 m (15.0 ft) south of the south rail of
a railroad spur, and 0.91 m (3.0 ft) above road level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9440422 PUBLICATION DATE: 09/07/2004
Name: LONGVIEW, COLUMBIA RIVER
WASHINGTON
NOAA Chart: 18524 Latitude: 46° 6.5' N
USGS Quad: RAINIER Longitude: 122° 57.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: LVW-A 1985
DESIGNATION: 944 0422 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 16641
AGENCY: National Ocean Service (NOS) PID#: SC1113
SETTING CLASSIFICATION: Concrete retaining wall
The bench mark is a disk set flush in a 0.15 m (0.5 ft) wide concrete retaining
wall which is level with the asphalt pavement, located along the northern side
of transit shed No. 2, Port of Longview, 26.52 m (87.0 ft) south of gear locker
"A", 19.20 m (63.0 ft) NE of the NW corner of shed No. 2 at the end of a yellow
wooden bullrail, 4.36 m (14.3 ft) north of transit shed No. 2, and 0.24 m (0.8
ft) east of the east end of bullrail.
BENCH MARK STAMPING: 0422 D 1990
DESIGNATION: 944 0422 D
MONUMENTATION: Tidal Station disk VM#: 16642
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete column support foundation
The bench mark is a disk set flush in a square concrete bumper cast around the
western-most "I" beam column which supports the north lean to shed at transit
shed 3, 5.24 m (17.2 ft) SW of railroad tracks, 4.45 m (14.6 ft) NE of the
northern-most corner of transit shed 3, and 1.22 m (4.0 ft) above the roadway.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9440422 PUBLICATION DATE: 09/07/2004
Name: LONGVIEW, COLUMBIA RIVER
WASHINGTON
NOAA Chart: 18524 Latitude: 46° 6.5' N
USGS Quad: RAINIER Longitude: 122° 57.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: SA 89 MON 4
DESIGNATION: 944 0422 SA 89 MON 4
MONUMENTATION: Bench Mark disk VM#: 16643
AGENCY: Port of Longview PID:
SETTING CLASSIFICATION: Concrete monument
The bench mark is a disk set in a 0.49 m (1.6 ft) square concrete block near
railroad tracks at the Port of Longview, 20.12 m (66.0 ft) south of rail switch
5538, 10.36 m (34.0 ft) north of water tower, 2.59 m (8.5 ft) SW of the
western-most set of tracks, and 0.61 m (2.0 ft) SW from the edge of the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9440422 PUBLICATION DATE: 09/07/2004
Name: LONGVIEW, COLUMBIA RIVER
WASHINGTON
NOAA Chart: 18524 Latitude: 46° 6.5' N
USGS Quad: RAINIER Longitude: 122° 57.4' W
T I D A L D A T U M S
Tidal datums at LONGVIEW, COLUMBIA RIVER based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: August 2002 - October 2002
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9439040 ASTORIA, TONGUE POINT, COLUMBIA RIVER
Elevations of tidal datums referred to Columbia River Datum (CRD), in METERS:
MEAN HIGHER HIGH WATER (MHHW) = 1.396
MEAN HIGH WATER (MHW) = 1.246
MEAN TIDE LEVEL (MTL) = 0.675
MEAN SEA LEVEL (MSL) = 0.627
MEAN LOW WATER (MLW) = 0.105
MEAN LOWER LOW WATER (MLLW) = 0.000
Columbia River Datum (CRD) = 0.000
NORTH AMERICAN VERTICAL DATUM-1988 (NAVD) = -1.499
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In METERS above:
Stamping or Designation CRD MHW
NO 5 1949 7.605 6.359
6 1951 8.460 7.214
LVW-A 1985 8.414 7.168
0422 D 1990 9.405 8.159
SA 89 MON 4 8.313 7.067
Foot Notes:
Data was collected on Columbia River Datum (CRD). Datums computed on 3 months
of lowest river levels. Depending on river flow, water levles can be
significantly different from published datums. CRD for this station is 0.755
meters below MLLW.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9440422 PUBLICATION DATE: 09/07/2004
Name: LONGVIEW, COLUMBIA RIVER
WASHINGTON
NOAA Chart: 18524 Latitude: 46° 6.5' N
USGS Quad: RAINIER Longitude: 122° 57.4' W
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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.