U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9449982 PUBLICATION DATE: 04/21/2003
Name: RICHARDSON, LOPEZ ISLAND
WA
NOAA Chart: 18434 Latitude: 48° 26.8' N ( 48.44670)
USGS Quad: RICHARDSON Longitude: 122° 54.0' W (-122.90000)
To reach the tidal bench marks at Richardson Point from Anacortes, take the
Washington State Ferry from Anacortes to Lopez Island. From the ferry landing,
drive south on Ferry Road for 0.6 km (0.4 mi) to the Center Road intersection.
Turn east (left) onto Center Road which turns south and continue for 9.0 km (5.6
mi) to the intersection with Fishman Bay Road. Turn west (right) onto Fisherman
Bay Road, proceed west 0.3 km (0.2 mi) and turn south (left) onto Richardson
Road. Continue south on Richardson Road 2.9 km (1.8 mi) to the Richardson Point
Chevron Oil Pier at the end of the road. The bench marks were in the general
vicinity. The tide gauge was located on the Chevron Oil Pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 3 1942
DESIGNATION: 944 9982 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 13733
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 48° 26.8' N ( 48.44670) LONGITUDE: 122° 54.0' W (-122.90000)
The primary bench mark is a disk set in old concrete footing 0.3 m x 1 m (1 ft x
4 ft) at edge of rocky point, 30 m (98 ft) east of Post Office and store, 15 m
(50 ft) south of wall surrounding three silver-colored storage tanks, 2 m (6 ft)
east of east face of oil wharf, and 6 m (20 ft) above the apparent high water
line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9449982 PUBLICATION DATE: 04/21/2003
Name: RICHARDSON, LOPEZ ISLAND
WA
NOAA Chart: 18434 Latitude: 48° 26.8' N ( 48.44670)
USGS Quad: RICHARDSON Longitude: 122° 54.0' W (-122.90000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 4 1942
DESIGNATION: 944 9982 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 13734
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Rock ledge OPUS PID:
LATITUDE: 48° 26.8' N ( 48.44670) LONGITUDE: 122° 54.0' W (-122.90000)
The bench mark is a disk set in a ledge rock on a rocky bluff, 53 m (174 ft)
east of Post Office and store, 12 m (40 ft) east of wall surrounding the
silver-colored storage tanks, 2 m (6 ft) west of rocky bluff line, and 6 m (20
ft) above the apparent high water line.
BENCH MARK STAMPING: NO 5 1942
DESIGNATION: 944 9982 TIDAL 5
MONUMENTATION: Tidal Station disk VM#: 13735
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 48° 26.8' N ( 48.44670) LONGITUDE: 122° 54.0' W (-122.90000)
The bench mark is a disk set in rock outcrop, 23 m (75 ft) east of Post Office
and store, 8 m (26 ft) north of north end of oil wharf, and 3 m (10 ft) south of
around group of oil storage tanks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9449982 PUBLICATION DATE: 04/21/2003
Name: RICHARDSON, LOPEZ ISLAND
WA
NOAA Chart: 18434 Latitude: 48° 26.8' N ( 48.44670)
USGS Quad: RICHARDSON Longitude: 122° 54.0' W (-122.90000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TIDAL BM 6
DESIGNATION: 944 9982 TIDAL BM 6
MONUMENTATION: Tidal Station disk VM#: 13736
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 48° 26.8' N ( 48.44670) LONGITUDE: 122° 54.0' W (-122.90000)
The bench mark is a disk set in bedrock, 27 m (89 ft) NE (80 degrees magnetic)
across gulley from bench mark NO 4 1942, and 6 m (20 ft) from edge of cliff.
BENCH MARK STAMPING: TIDAL BM 7
DESIGNATION: 944 9982 TIDAL BM 7
MONUMENTATION: Tidal Station disk VM#: 13737
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 48° 26.8' N ( 48.44670) LONGITUDE: 122° 54.0' W (-122.90000)
The bench mark is a disk set in bedrock, 50 m (165 ft) NW (310 degrees magnetic)
from bench mark TIDAL BM 6, and 1 m (4 ft) NE (20 degrees magnetic) from the
edge of bluff east of road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9449982 PUBLICATION DATE: 04/21/2003
Name: RICHARDSON, LOPEZ ISLAND
WA
NOAA Chart: 18434 Latitude: 48° 26.8' N ( 48.44670)
USGS Quad: RICHARDSON Longitude: 122° 54.0' W (-122.90000)
T I D A L D A T U M S
Tidal datums at RICHARDSON, LOPEZ ISLAND based on:
LENGTH OF SERIES: 3 Years
TIME PERIOD: April 1998 - March 2000
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9449880 FRIDAY HARBOR, SAN JUAN CHANNEL
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (12/16/1997) = 2.920
MEAN HIGHER HIGH WATER MHHW = 2.185
MEAN HIGH WATER MHW = 2.023
MEAN TIDE LEVEL MTL = 1.330
MEAN SEA LEVEL MSL = 1.313
MEAN LOW WATER MLW = 0.637
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/24/1999) = -1.173
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 3 1942 6.141 4.118
NO 4 1942 5.809 3.786
NO 5 1942 6.675 4.652
TIDAL BM 6 7.439 5.416
TIDAL BM 7 11.151 9.128
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9449982 PUBLICATION DATE: 04/21/2003
Name: RICHARDSON, LOPEZ ISLAND
WA
NOAA Chart: 18434 Latitude: 48° 26.8' N ( 48.44670)
USGS Quad: RICHARDSON Longitude: 122° 54.0' W (-122.90000)
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.