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Datums Page Page 1 of 6
Station ID: 9434939 PUBLICATION DATE: 03/28/2014
Name: WALDPORT, ALSEA BAY
OR
NOAA Chart: 18561 Latitude: 44° 26.1' N ( 44.43436)
USGS Quad: WALDPORT Longitude: 124° 3.5' W (-124.05808)
TO REACH THE STATION FROM THE INTERSECTION OF US HIGHWAY 101 AND OREGON STATE
HIGHWAY 34 (HEMLOCKSTREET) PROCEED EAST ON OREGON STATE HIGHWAY 34 FOR 1.4 KM
(0.9 MI) TO THE INTERSECTION WITH MILL STREET, TURN LEFT AND PROCEED NORTH 0.5
KM (0.3 MI) TO THE END OF MILL STREET AND TURN RIGHT INTO A GRAVEL PARKING LOT.
THE STATION IS LOCATED ON THE SOUTH FACE OF THE EASTERNMOST PIER AT THE ALSEA
BAY BOAT DOCKS. THE BENCHMARKS ARE LOCATED WITHIN 1.0 KM (0.6 MI) ON THE BRIDGE
OVER LINT SLOUGH ON OREGON 34, IN THE BOAT DOCK AREA, AND ON THE SOUTH END OF
THE US HIGHWAY 101 BRIDGE OVER THE ALSEA RIVER.
T I D A L B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9434939 PUBLICATION DATE: 03/28/2014
Name: WALDPORT, ALSEA BAY
OR
NOAA Chart: 18561 Latitude: 44° 26.1' N ( 44.43436)
USGS Quad: WALDPORT Longitude: 124° 3.5' W (-124.05808)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: X 79 1933 EL 12
DESIGNATION: X 79
MONUMENTATION: Bench Mark disk VM#: 20761
AGENCY: Oregon Highway Department IDB PID#: QE1304
SETTING CLASSIFICATION: Wingwall OPUS PID:
LATITUDE: 44° 25.8' N ( 44.43061) LONGITUDE: 124° 3.5' W (-124.05783)
THE BENCH MARK IS A DISK SET IN A WING WALL ON THE SE BRIDGE ABUTMENT, 79.60 M
(261.2 FT) SW OF THE INTERSECTION OF WALDPORT HEIGHTS DRIVE AND OREGON STATE
ROAD 34, 0.58 M (1.9 FT) SE OF THE E CONCRETE BRIDGE RAIL, 0.26 M (0.9 FT) W OF
E EDGE OF THE CONCRETE WING WALL AND ABOUT 0.71 M (2.3 FT) ABOVE THE GROUND.
BENCH MARK STAMPING: 4939 A 2013
DESIGNATION: 943 4939 A
MONUMENTATION: Bench Mark disk VM#: 20762
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Set in a concrete mat OPUS PID:
LATITUDE: 44° 26.0' N ( 44.43406) LONGITUDE: 124° 3.5' W (-124.05794)
THE BENCH MARK IS A DISK SET IN A CONCRETE MAT FOR A PARK BENCH, 24.33 M (79.8
FT) ESE OF THE CENTER OF THE WALKWAY TO THE WOODEN DOCK, 18.07 M (59.3 FT) SSE
OF A UTILITY POLE NUMBERED L18R 34, 8.87 M (29.1 FT) NNE OF A CORNER OF A CHAIN
LINK FENCE, 4.84 M (15.9 FT) ESE OF THE SE CORNER OF THE CRAB SHACK RESTAURANT
AND 2.19 M (7.2 FT) ESE OF A PICNIC GRILL.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9434939 PUBLICATION DATE: 03/28/2014
Name: WALDPORT, ALSEA BAY
OR
NOAA Chart: 18561 Latitude: 44° 26.1' N ( 44.43436)
USGS Quad: WALDPORT Longitude: 124° 3.5' W (-124.05808)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: A 2 1936 13.4
DESIGNATION: A 2
MONUMENTATION: Bench Mark disk VM#: 20763
AGENCY: Oregon Highway Department IDB PID#: QE1309
SETTING CLASSIFICATION: Platform OPUS PID:
LATITUDE: 44° 25.7' N ( 44.42831) LONGITUDE: 124° 4.1' W (-124.06761)
THE BENCH MARK IS A DISK SET IN A CONCRETE PLATFORM, 24.43 M (80.2 FT) NW OF THE
CENTER OF THE ROUND WINDOW OF VISITORS CENTER, 14.88 M (48.8 FT) SSW OF CURB OF
US HIGHWAY 101, 14.39 M (47.2 FT) S OF SE LEG OF THE 20 M (65.6 FT) SE BRIDGE
SPIRE, 3.67 M (12.0 FT) SW OF THE NE EDGE OF CONCRETE PAD AND STEPS, 2.29 M (7.5
FT) NW OF THE TOP OF THE STAIRS AND ABOUT 1.67 M (5.5 FT) ABOVE THE BEACH.
BENCH MARK STAMPING: 2 1933
DESIGNATION: 943 4939 Tidal 2
MONUMENTATION: Tidal Station disk VM#: 20764
AGENCY: US Coast and Geodetic Survey IDB PID#: QE1307
SETTING CLASSIFICATION: Top of concrete monument OPUS PID:
LATITUDE: 44° 26.0' N ( 44.43403) LONGITUDE: 124° 3.5' W (-124.05900)
THE BENCH MARK IS A DISK SET IN A CONCRETE POST IN BETWEEN THE STRUCTURES ON THE
PROPERTIES OF 1180 AND 1220 N MILL STREET, 82.39 M (270.3 FT) WSW OF BENCH MARK
943 4939 A, 70.38 M (230.9 FT) N OF OF CENTER LINE OF SPENCER STREET, 16.64 M
(54.6 FT) S OF A UTILITY POLE NUMBERED L18R9, 10.74 M (35.2 FT) E OF THE CENTER
LINE OF MILL STREET, 0.88 M (2.9 FT) E OF THE E SIDE OF THE SIDE WALK AND SET IN
THE TOP OF A 19-CM (7 INCH) ROUND CONCRETE POST AND ABOUT 0.08 M (0.3 FT) ABOVE
GRADE.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9434939 PUBLICATION DATE: 03/28/2014
Name: WALDPORT, ALSEA BAY
OR
NOAA Chart: 18561 Latitude: 44° 26.1' N ( 44.43436)
USGS Quad: WALDPORT Longitude: 124° 3.5' W (-124.05808)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4939 B 2013
DESIGNATION: 943 4939 B
MONUMENTATION: Bench Mark disk VM#: 20765
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Concrete pier ramp OPUS PID#: BBDB75
LATITUDE: 44° 26.1' N ( 44.43481) LONGITUDE: 124° 3.6' W (-124.05986)
THE BENCH MARK IS A DISK SET IN A CONCRETE PEDESTRIAN RAMP LEADING TO THE PIER,
41.98 M (137.7 FT) N OF A STOP SIGN AT THE INTERSECTION OF BROADWAY AND PORT
STREETS, 37.47 M (122.9 FT) WNW OF A UTILITY POLE NUMBERED L18R13, 34.72 M
(113.9 FT) WSW OF THE LAST PILING ON THE PIER, 7.94 M (26.0 FT) N OF THE SW
CORNER OF THE CONCRETE BOAT LAUNCH RAMP AND 4.89 M (16.0 FT) E OF E-MOST POST OF
THE ALSEA PORT SIGN.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9434939 PUBLICATION DATE: 03/28/2014
Name: WALDPORT, ALSEA BAY
OR
NOAA Chart: 18561 Latitude: 44° 26.1' N ( 44.43436)
USGS Quad: WALDPORT Longitude: 124° 3.5' W (-124.05808)
T I D A L D A T U M S
Tidal datums at WALDPORT, ALSEA BAY based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: June 2013 - September 2013
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9435380 SOUTH BEACH, YAQUINA RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.313
MEAN HIGH WATER MHW = 2.096
MEAN SEA LEVEL MSL = 1.245
MEAN TIDE LEVEL MTL = 1.239
MEAN LOW WATER MLW = 0.381
North American Vertical Datum NAVD88 = 0.012
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
X 79 1933 EL 12 4.906 2.810
4939 A 2013 4.060 1.964
A 2 1936 13.4 5.241 3.145
2 1933 4.682 2.586
4939 B 2013 3.954 1.858
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9434939 PUBLICATION DATE: 03/28/2014
Name: WALDPORT, ALSEA BAY
OR
NOAA Chart: 18561 Latitude: 44° 26.1' N ( 44.43436)
USGS Quad: WALDPORT Longitude: 124° 3.5' W (-124.05808)
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.