U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                                                
Station ID: 9440422                         PUBLICATION DATE:  09/20/2023
Name:       LONGVIEW, COLUMBIA RIVER                          
            WA
NOAA Chart: 18524                           Latitude:   46°  6.4' N (  46.10614)
USGS Quad:  RAINIER                         Longitude: 122° 57.3' W (-122.95419)


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,
stop at security shack, then drive straight to the water front.  Turn left on
the wharf and drive about 300 m (1000 ft) up the river under a grain conveyor
and stop at Transit Shed 3.  The tide house is located adjacent to the SE corner
of Transit Shed 3. The tidal bench mark are located located in the vicinity. The
tide station is a 6 x 6 fiberglass house. The sensors are located beneath the
pier deck and can be accessed by a set of stairs 20 m SE of the tide house. The
sensors are about 10 m west of the bottom of the stairs, adjacent to and on each
side of the catwalk.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  LVW-A 1985
                         DESIGNATION:          944 0422 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:        16641
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete retaining wall               OPUS PID:        
LATITUDE:   46°  6.5' N (  46.10753)          LONGITUDE: 122° 57.4' W (-122.95672)


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.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 9440422                         PUBLICATION DATE:  09/20/2023
Name:       LONGVIEW, COLUMBIA RIVER                          
            WA
NOAA Chart: 18524                           Latitude:   46°  6.4' N (  46.10614)
USGS Quad:  RAINIER                         Longitude: 122° 57.3' W (-122.95419)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  0422 D 1990
                         DESIGNATION:          944 0422 D

MONUMENTATION:           Tidal Station disk                    VM#:        16642
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete column support foundation    OPUS PID:        
LATITUDE:   46°  6.4' N (  46.10697)          LONGITUDE: 122° 57.3' W (-122.95556)


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.



                         BENCH MARK STAMPING:  0422 E 2004
                         DESIGNATION:          944 0422 E

MONUMENTATION:           Flange-encased Rod                    VM#:        17732
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID:        
LATITUDE:   46°  6.4' N (  46.10639)          LONGITUDE: 122° 57.3' W (-122.95417)


The primary bench mark is located on the south side of the shore road by Berth 3
at the Port of Longview, WA, located at the NW corner of a condemned section of
Berth 3, 25.48 m (83.6 ft) SW of a group of 3 red water valves surrounded by
yellow crash guard, 21.64 m (71.0 ft) SE of a yellow fire hydrant, 19.20 m (63.0
ft) south of the south rail of the railroad tracks, and north of an orange
fiberglass witness post.  The bench mark is top of a 1/2-inch stainless steel
rod driven 34.1 m (112 ft) to refusal and encased inside a 5-inch PVC pipe with
an aluminum hinged cover stamped 0422 E 2004.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 9440422                         PUBLICATION DATE:  09/20/2023
Name:       LONGVIEW, COLUMBIA RIVER                          
            WA
NOAA Chart: 18524                           Latitude:   46°  6.4' N (  46.10614)
USGS Quad:  RAINIER                         Longitude: 122° 57.3' W (-122.95419)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  0422 F 2004
                         DESIGNATION:          944 0422 F

MONUMENTATION:           Tidal Station disk                    VM#:        17733
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   46°  6.3' N (  46.10444)          LONGITUDE: 122° 57.0' W (-122.95000)


The bench mark is a disk set in the SW side of the concrete base of a large
green tank on the north side of the shore road at Berth 5 at the Port of
Longview, WA, located below a "Speed Limit 8" sign, 25.76 m (84.5 ft) west of a
fire hydrant on the south side of the road, 7.22 m (23.7 ft) north of a guard
rail on the south side of the road, 4.72 m (15.5 ft) SE of the door on the south
side of a small building on the west side of the tank, and 0.73 m (2.4 ft) above
the ground.



                         BENCH MARK STAMPING:  0422 G 2004
                         DESIGNATION:          944 0422 G

MONUMENTATION:           Flange-encased Rod                    VM#:        17734
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID:        
LATITUDE:   46°  6.3' N (  46.10528)          LONGITUDE: 122° 57.1' W (-122.95194)


The bench mark is located on the south side of the shore road north of Berth 4
at the Port of Longview, Wa, located 17.68 m (58.0 ft) south of the centerline
of the road, 2.13 m (7.0 ft) north of the top of the slope to the river, 2.04 m
(6.7 ft) SE of the end of the concrete parking barrier, 0.98 m (3.2 ft) south of
the west end of the guard rail, and north of an orange fiberglass witness post. 
The bench mark is top of a 1/2-inch stainless steel rod driven 4.9 m (16.1 ft)
to refusal, and encased inside a 5-inch PVC pipe with an aluminum hinged cover
stamped 0422 G 2004.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 9440422                         PUBLICATION DATE:  09/20/2023
Name:       LONGVIEW, COLUMBIA RIVER                          
            WA
NOAA Chart: 18524                           Latitude:   46°  6.4' N (  46.10614)
USGS Quad:  RAINIER                         Longitude: 122° 57.3' W (-122.95419)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  0422 H 2004
                         DESIGNATION:          944 0422 H

MONUMENTATION:           Flange-encased Rod                    VM#:        17735
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID:        
LATITUDE:   46°  6.3' N (  46.10492)          LONGITUDE: 122° 57.1' W (-122.95092)


The bench mark is located on the south side of the shore road, north of the east
end of Berth 4 at the Port of Longview, Wa, located 26.0 m (85.3 ft) west of the
SW corner of "Small Building 76" which covers some picnic tables, 2.59 m (8.5
ft) north of the top of the slope to the river, 1.46 m (4.8 ft) south of a
yellow guard rail, and north of an orange fiberglass witness post.  The bench
mark is top of a 1/2-inch stainless steel rod driven 26.8 m (88 ft) to refusal
and encased inside a 5-inch PVC pipe with an aluminum hinged cover stamped 0422
H 2004.



                         BENCH MARK STAMPING:  0422 J 2004
                         DESIGNATION:          944 0422 J

MONUMENTATION:           Tidal Station disk                    VM#:        17736
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete ramp                         OPUS PID:        
LATITUDE:   46°  6.3' N (  46.10550)          LONGITUDE: 122° 57.1' W (-122.95233)


The bench mark is a disk set in the top of a concrete ramp leading to the south
entrance of a metal building on the north side of the shore road between Berth 4
and 5 at the Port of Longview, WA, located 19.35 m (63.5 ft) west of the SE
corner of the building, 11.16 m (36.6 ft) north of the south side of the road,
5.43 m (17.8 ft) east of the SW edge of the building, and 0.70 m (2.3 ft) above
the ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 9440422                         PUBLICATION DATE:  09/20/2023
Name:       LONGVIEW, COLUMBIA RIVER                          
            WA
NOAA Chart: 18524                           Latitude:   46°  6.4' N (  46.10614)
USGS Quad:  RAINIER                         Longitude: 122° 57.3' W (-122.95419)


                            T I D A L   D A T U M S 


Tidal datums at LONGVIEW, COLUMBIA RIVER based on:

     LENGTH OF SERIES:      14 Years
     TIME PERIOD:           8/2002 - 9/2015 Low Water Months Only
     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   =  1.992
     MEAN HIGH WATER                            MHW    =  1.849
     MEAN TIDE LEVEL                            MTL    =  1.289
     MEAN SEA LEVEL                             MSL    =  1.243
     MEAN LOW WATER                             MLW    =  0.729
     MEAN LOWER LOW WATER                       MLLW   =  0.629
     COLUMBIA RIVER DATUM                       CRD    =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MHW         CRD

     LVW-A 1985                                  7.213    9.062
     0422 D 1990                                 8.203   10.052
     0422 E 2004                                 7.018    8.867
     0422 F 2004                                 7.484    9.333
     0422 G 2004                                 5.967    7.816
     0422 H 2004                                 7.255    9.104
     0422 J 2004                                 4.864    6.713


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 9440422                         PUBLICATION DATE:  09/20/2023
Name:       LONGVIEW, COLUMBIA RIVER                          
            WA
NOAA Chart: 18524                           Latitude:   46°  6.4' N (  46.10614)
USGS Quad:  RAINIER                         Longitude: 122° 57.3' W (-122.95419)


Foot Notes:

 Columbia River Datum (CRD) is the adopted fixed low water reference plane for
this area. CRD is a U.S. Army Corps of Engineers non-tidal datum defined at
distinct river miles relative to NAVD88, and is used as chart datum above river
mile 23 on the Columbia River. Datums are computed using observations from the
low river stages of the year, generally August through October due to the
masking of the tidal signal from strong seasonal river runoff during other
portions of the year. Depending on river flow, water levels can be significantly
higher than Columbia River Datum. As of 2014, the U.S. Army Corps of Engineers
provided updated offsets for CRD that have been applied to this station. Station
Datum (STND) is no longer set equal to CRD.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  7

                                                                                
Station ID: 9440422                         PUBLICATION DATE:  09/20/2023
Name:       LONGVIEW, COLUMBIA RIVER                          
            WA
NOAA Chart: 18524                           Latitude:   46°  6.4' N (  46.10614)
USGS Quad:  RAINIER                         Longitude: 122° 57.3' W (-122.95419)


                             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.