U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 1 of 5
Station ID: 9440574 PUBLICATION DATE: 01/06/2004
Name: NORTH JETTY
WASHINGTON
NOAA Chart: 18521 Latitude: 46ø 16.4' N
USGS Quad: CAPE DISAPPOINTMENT Longitude: 124ø 4.3' W
To reach the tidal bench marks from the center of town of Ilwaco (where U.S.
Highway 101 marks a turn to north), proceed west one block and turn left at sign
CAPE DISAPPOINTMENT, continue south for 2.7 km (1.7 mi) to "Y" intersection,
turn left, and continue for 0.8 km (0.5 mi) to the entrance of Fort Canby State
Park; turn right into the park and proceed 2.1 km (1.3 mi) to a parking lot on
the left. The bench marks are located on the jetty east of the parking lot and
along the road between the parking lot and the camping area. The tide gage and
staff were located on the top of the rock jetty SE of the parking lot.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0574 A 1982
DESIGNATION: 944 0574 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 8938
AGENCY: National Ocean Survey (NOS) PID#: SD0299
SETTING CLASSIFICATION: Stainless steel rod
The primary bench mark is a disk located along the south side of the Jetty Road
in Fort Canby State Park, 1.9 km (1.2 mi) west along the jetty road from the
park entrance, 50 m (163 ft) east of the east edge of an entrance road into a
parking lot south of the Jetty Road, 7 m (23 ft) south of the south edge of the
jetty road, and 1 m (3 ft) NW of a witness post. The bench mark is set 6 cm
(0.2 ft) below the ground, crimped to the top of a stainless steel rod driven
14.6 m (48 ft) to refusal, and encased in a 4-inch PVC pipe and concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9440574 PUBLICATION DATE: 01/06/2004
Name: NORTH JETTY
WASHINGTON
NOAA Chart: 18521 Latitude: 46ø 16.4' N
USGS Quad: CAPE DISAPPOINTMENT Longitude: 124ø 4.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0574 B 1982
DESIGNATION: 944 0574 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 8939
AGENCY: National Ocean Survey (NOS) PID#: SD0298
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk located along the south side of the jetty road in Fort
Canby State Park, 1.6 km (1.0 mi) west along jetty road from the park entrance,
8 m (27 ft) south of the southern edge of the jetty road, and 1 m (2 ft) NW of a
witness post. The bench mark is set 15 cm (0.5 ft) below the ground, crimped to
the top of a stainless steel rod driven 14.6 m (48 ft) to refusal, and encased
in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 0574 C 1982
DESIGNATION: 944 0574 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 8940
AGENCY: National Ocean Survey (NOS) PID#: SD0297
SETTING CLASSIFICATION: Stainless steel rod
The bench mark is a disk located along the south side of the jetty road in Fort
Canby State Park, 1.1 km (0.7 mi) west along the jetty road from the park
entrance, 3 m (11 ft) south of the southern edge of jetty road, and 1 m (2 ft)
NW of a witness post. The bench mark is set 15 cm (0.5 ft) below the ground,
crimped to the top of a stainless steel rod driven 13.4 m (44 ft) to refusal,
and encased in a 4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9440574 PUBLICATION DATE: 01/06/2004
Name: NORTH JETTY
WASHINGTON
NOAA Chart: 18521 Latitude: 46ø 16.4' N
USGS Quad: CAPE DISAPPOINTMENT Longitude: 124ø 4.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0574 D 1982
DESIGNATION: 944 0574 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 8941
AGENCY: National Ocean Survey (NOS) PID#: SD0296
SETTING CLASSIFICATION: Concrete bunker
The bench mark is a disk set in the NW corner of a World War II machine gun
bunker, 45 m (146 ft) SE of the SE corner of the restroom building, 0.3 m (1 ft)
east of the west edge of the 2 m (8ft) square concrete bunker, 0.27 m (0.9 ft)
south of the north edge of the bunker, and 1.16 m (3.8 ft) above the ground.
BENCH MARK STAMPING: BM 1 1958
DESIGNATION: 944 0574 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 8942
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: SD0302
SETTING CLASSIFICATION: Boulder
The bench mark is a disk set in the top of a large light colored rock located at
the edge of the Columbia River, 69 m (225 ft) east of the parking lot, 3 m (10
ft) towards the river from a set of burned-out pilings, and 3 m (10 ft) below
the top of a levee. Note: The high point on the disk is "R" in MARK.
BENCH MARK STAMPING: BM 3 1958
DESIGNATION: 944 0574 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 8944
AGENCY: US Coast and Geodetic Survey (USC&GS) PID#: SD0300
SETTING CLASSIFICATION: Boulder
The bench mark is a disk set in the top of a large jetty rock located at the
edge of the Columbia River, 82 m (270 ft) east of the parking lot, 7 m (23 ft)
NE of bench mark BM 2 1958, and 3 m (10 ft) below the top of a levee. Note: The
high point on the disk is "D" in GEODETIC.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9440574 PUBLICATION DATE: 01/06/2004
Name: NORTH JETTY
WASHINGTON
NOAA Chart: 18521 Latitude: 46ø 16.4' N
USGS Quad: CAPE DISAPPOINTMENT Longitude: 124ø 4.3' W
T I D A L D A T U M S
Tidal datums at NORTH JETTY based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: July 1983 - October 1983
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9439040 ASTORIA, TONGUE POINT, COLUMBIA RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER (MHHW) = 2.361
MEAN HIGH WATER (MHW) = 2.156
MEAN TIDE LEVEL (MTL) = 1.265
MEAN SEA LEVEL (MSL) = 1.246
MEAN LOW WATER (MLW) = 0.374
NORTH AMERICAN VERTICAL DATUM-1988 (NAVD) = 0.077
MEAN LOWER LOW WATER (MLLW) = 0.000
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
0574 A 1982 4.949 2.793
0574 B 1982 4.782 2.626
0574 C 1982 4.754 2.598
0574 D 1982 7.447 5.291
BM 1 1958 5.900 3.744
BM 3 1958 4.327 2.171
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9440574 PUBLICATION DATE: 01/06/2004
Name: NORTH JETTY
WASHINGTON
NOAA Chart: 18521 Latitude: 46ø 16.4' N
USGS Quad: CAPE DISAPPOINTMENT Longitude: 124ø 4.3' 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.