U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9433445 PUBLICATION DATE: 03/24/2014
Name: HALF MOON BAY, UMPQUA RIVER
OR
NOAA Chart: 18584 Latitude: 43° 40.5' N ( 43.67500)
USGS Quad: WINCHESTER BAY Longitude: 124° 11.5' W (-124.19200)
To reach the station from the intersection of US Highway 101 and Oregon State
Highway 38 (Umpqua Highway) in Reedsport, proceed S on US Highway 101 for 6.9 km
(4.3 mi) to the intersection with Salmon Harbor Drive, turn right and proceed W
for 1.6 km (1.0 mi) to the Windy Cove parking area on the NW side of the road,
proceed N on foot to a long wooden pier orientated N-S. The station is 171 m
(560 ft) from the beginning of the pier on the W side, sheltered to the W by a
jetty. The benchmarks are located on Salmon Harbor Road from the bridge over
Winchester Creek to the parking lot at Windy Cove.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 13 1974
DESIGNATION: 943 3445 TIDAL 13
MONUMENTATION: Bench Mark disk VM#: 20775
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID#: BBDB84
LATITUDE: 43° 40.3' N ( 43.67228) LONGITUDE: 124° 11.5' W (-124.19181)
THE BENCH MARK IS A DISK SET IN BEDROCK, 81.15 M (266.2 FT) NNE OF NW POST OF
THE WINDY COVE PARK SIGN, 32.71 M (107.3 FT) ESE OF THE TOP OF THE JETTY ROCK
WALL, 14.35 M (47.1 FT) NNW OF NW POINT OF ROCK OUTCROP ON E SIDE OF SALMON
HARBOR DRIVE, 6.95 M (22.8 FT) NW OF THE CENTERLINE OF SALMON HARBOR DRIVE, 0.89
M (2.9 FT) ENE OF TALLEST POINT OF THE ROCK OUTCROP AND ABOUT 1.35 M (4.4 FT)
ABOVE THE GROUND.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9433445 PUBLICATION DATE: 03/24/2014
Name: HALF MOON BAY, UMPQUA RIVER
OR
NOAA Chart: 18584 Latitude: 43° 40.5' N ( 43.67500)
USGS Quad: WINCHESTER BAY Longitude: 124° 11.5' W (-124.19200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: CINDYS 2006
DESIGNATION: CINDYS
MONUMENTATION: Bench Mark disk VM#: 20776
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Conc utility mat OPUS PID:
LATITUDE: 43° 40.5' N ( 43.67575) LONGITUDE: 124° 11.2' W (-124.18639)
THE BENCH MARK IS A DISK SET IN A CONCRETE UTILITY ACCESS HATCH, 28.48 M (93.4
FT) SSE OF A FIRE HYDRANT ON A GRAVEL ACCESS ROAD, 14.53 M (47.7 FT) NNE OF THE
CENTERLINE OF SALMON HARBOR DRIVE, 5.23 M (17.2 FT) SE OF THE SW CORNER OF A
GRAY UTILITY SHED, 4.52 M (14.8 FT) SSE OF A METAL UTILITY POLE WITH A LIGHT,
1.98 M (6.5 FT) SW OF THE CENTER OF THE METAL UNDERGROUND ACCESS DOORS AND ABOUT
0.22 M (0.7 FT) ABOVE THE GROUND.
BENCH MARK STAMPING: 3445 A 2013
DESIGNATION: 943 3445 A
MONUMENTATION: Bench Mark disk VM#: 20777
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Conc memorial footing OPUS PID:
LATITUDE: 43° 40.5' N ( 43.67583) LONGITUDE: 124° 11.0' W (-124.18261)
THE BENCH MARK IS A DISK SET IN THE CONCRETE FOOTING OF THE FISHERMAN'S
MEMORIAL, 81.03 M (265.8 FT) WNW OF VERTICAL BENCH MARK J 754, 68.04 M (223.2
FT) NE OF THE NW CORNER OF A BRICK RESTROOM BUILDING, 20.81 M (68.3 FT) N OF THE
CENTERLINE OF SALMON HARBOR DRIVE, 7.44 M (24.4 FT) S OF THE MEAN HIGH WATER
LINE, 0.40 M (1.3 FT) N OF THE CENTER OF THE FISHERMAN'S MEMORIAL DOLPHIN MAST
AND ABOUT 0.42 M (1.4 FT) ABOVE THE GROUND.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9433445 PUBLICATION DATE: 03/24/2014
Name: HALF MOON BAY, UMPQUA RIVER
OR
NOAA Chart: 18584 Latitude: 43° 40.5' N ( 43.67500)
USGS Quad: WINCHESTER BAY Longitude: 124° 11.5' W (-124.19200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: J 754 1988
DESIGNATION: J 754
MONUMENTATION: Bench Mark disk VM#: 20778
AGENCY: National Ocean Service (NOS) IDB PID#: OA0678
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 43° 40.5' N ( 43.67556) LONGITUDE: 124° 10.9' W (-124.18169)
THE BENCH MARK IS A DISK SET VERTICALLY IN A 5 M (16.4 FT) TALL ROCK OUTCROP ON
THE S SIDE OF SALMON HARBOR DRIVE, 81.03 M (265.8 FT) ESE OF BENCH MARK 943 3445
A, 15.85 M (52.0 FT) S OF THE CENTERLINE OF SALMON HARBOR DRIVE, 15.35 M (50.4
FT) W OF A UTILITY POLE NUMBERED 268, 5.60 M (18.4 FT) WSW OF A FIRE HYDRANT AND
SET VERTICALLY IN THE N FACE OF THE ROCK OUTCROP ABOUT 1.23 M (4.0 FT) ABOVE THE
GROUND.
BENCH MARK STAMPING: TIDAL 12 1973
DESIGNATION: 943 3445 TIDAL 12
MONUMENTATION: Bench Mark disk VM#: 20779
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Wind wall of bridge OPUS PID:
LATITUDE: 43° 40.5' N ( 43.67556) LONGITUDE: 124° 10.9' W (-124.18169)
THE BENCH MARK IS A DISK SET IN THE NW WING WALL OF THE BRIDGE 34.83 M (114.3
FT) ESE OF THE NW POST OF THE ENTERING WINDY PARK SIGN, 11.07 M (36.3 FT) NNE OF
A UTILITY POLE NUMBERED AG07L023, 5.83 M (19.1 FT) SSE OF A BOLLARD ON THE W
SIDE OF A FOOT BRIDGE, 4.40 M (14.4 FT) NNE OF THE CENTERLINE OF SALMON HARBOR
ROAD AND 0.60 M (2.0 FT) SSE OF END OF THE NW CORNER OF THE BRIDGE.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9433445 PUBLICATION DATE: 03/24/2014
Name: HALF MOON BAY, UMPQUA RIVER
OR
NOAA Chart: 18584 Latitude: 43° 40.5' N ( 43.67500)
USGS Quad: WINCHESTER BAY Longitude: 124° 11.5' W (-124.19200)
T I D A L D A T U M S
Tidal datums at HALF MOON BAY, UMPQUA RIVER based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: June 2013 - September 2013
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9432780 CHARLESTON, COOS BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.177
MEAN HIGH WATER MHW = 1.979
MEAN TIDE LEVEL MTL = 1.173
MEAN SEA LEVEL MSL = 1.161
MEAN LOW WATER MLW = 0.367
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 13 1974 6.435 4.456
CINDYS 2006 4.690 2.711
3445 A 2013 4.552 2.573
J 754 1988 5.187 3.208
TIDAL 12 1973 5.045 3.066
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9433445 PUBLICATION DATE: 03/24/2014
Name: HALF MOON BAY, UMPQUA RIVER
OR
NOAA Chart: 18584 Latitude: 43° 40.5' N ( 43.67500)
USGS Quad: WINCHESTER BAY Longitude: 124° 11.5' W (-124.19200)
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.