U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 9413623 PUBLICATION DATE: 01/06/2004
Name: ELKHORN SLOUGH, ENTRANCE BRIDGE
CA
NOAA Chart: 18685 Latitude: 36° 48.6' N ( 36.81000)
USGS Quad: MOSS LANDING Longitude: 121° 47.1' W (-121.78500)
To reach the tidal bench marks from the Elkhorn Slough Highway Bridge, proceed
0.3 km (0.2 mi) north on State Highway 1 on Pauls Island, then turn left and
proceed west on the road leading to the yacht club. The bench marks are located
along State Highway 1 and the vicinity of the yacht club. The tide gage and
staff were located west of west side of bridge near floating fish pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 3623 A 1976
DESIGNATION: 941 3623 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 8057
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Abutment OPUS PID:
LATITUDE: 36° 48.6' N ( 36.81000) LONGITUDE: 121° 47.1' W (-121.78500)
The primary bench mark is a disk set horizontally in the abutment at the north
end of bridge, on the west side of the Highway 1 bridge across the slough, 23 m
(75 ft) NE from front door of Harbor Inn, 5.33 m (17.5 ft) SSW from centerline
of bridge, 0.46 m (1.5 ft) south of concrete seawall running west from north end
of the bridge and 1.13 m (3.7 ft) below level of curb.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 9413623 PUBLICATION DATE: 01/06/2004
Name: ELKHORN SLOUGH, ENTRANCE BRIDGE
CA
NOAA Chart: 18685 Latitude: 36° 48.6' N ( 36.81000)
USGS Quad: MOSS LANDING Longitude: 121° 47.1' W (-121.78500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3623 C 1976
DESIGNATION: 941 3623 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 8058
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 36° 48.6' N ( 36.81000) LONGITUDE: 121° 47.1' W (-121.78500)
The bench mark is a disk located on east side of Highway 1 (Cabrillo Highway),
198 m (650 ft) north of bench mark 3623 A 1976, 183 m (600 ft) north of bridge
over slough, 114 m (375 ft) southwest of bench mark 3623 D 1976, 24.4 m (80 ft)
west of wood bulkhead of salt pond, 13 m (43 ft) east of centerline of Highway
1, 0.45 m (1.5 ft) south of a telephone pole and level with ground. The bench
mark is set on top of a copper-clad steel rod driven 18.3 m (60 ft) to refusal
and encased in a PVC pipe.
BENCH MARK STAMPING: 3623 D 1976
DESIGNATION: 941 3623 D TIDAL
MONUMENTATION: Tidal Station disk VM#: 8059
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 36° 48.6' N ( 36.81000) LONGITUDE: 121° 47.1' W (-121.78500)
The bench mark is a disk located on the east side of the highway near the
Monterey Bay Salt Company Office, 0.3 km (0.2 mi) north of Highway 1 across the
slough, 183 m (600 ft) SE of bench mark 3623 E 1976, 114 m (375 ft) NE of bench
mark 3623 C 1976, 76 m (250 ft) east of the centerline of Highway 1, 10.85 m
(35.6 ft) north of a wooden power pole, and 3.57 m (11.7 ft) NW of the SW corner
of the Office. The bench mark is set on top of a copper-clad steel rod driven
an unspecified depth to refusal and encased in a PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 9413623 PUBLICATION DATE: 01/06/2004
Name: ELKHORN SLOUGH, ENTRANCE BRIDGE
CA
NOAA Chart: 18685 Latitude: 36° 48.6' N ( 36.81000)
USGS Quad: MOSS LANDING Longitude: 121° 47.1' W (-121.78500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3623 E 1976
DESIGNATION: 941 3623 E TIDAL
MONUMENTATION: Tidal Station disk VM#: 8060
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 36° 48.6' N ( 36.81000) LONGITUDE: 121° 47.1' W (-121.78500)
The bench mark is a disk on the west side of Highway 1, on north side of access
road to Moss Landing Yacht Club, 0.5 km (0.3 mi) north of bridge across the
slough, 73 m (241 ft) west of center of highway, 72 m (236 ft) east of entrance
gate of yacht club piers, 15 m (50 ft) north of NE corner of fenced boat storage
area, and 0.52 m (1.7 ft) north of a telephone pole. The bench mark is set on
top of a copper-clad steel rod driven 12.2 m (40 ft) to refusal and encased in a
PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 9413623 PUBLICATION DATE: 01/06/2004
Name: ELKHORN SLOUGH, ENTRANCE BRIDGE
CA
NOAA Chart: 18685 Latitude: 36° 48.6' N ( 36.81000)
USGS Quad: MOSS LANDING Longitude: 121° 47.1' W (-121.78500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: PURPLE 1972
DESIGNATION: PURPLE
MONUMENTATION: Tidal Station disk VM#: 8061
AGENCY: US Army Corps of Engineers (USE) IDB PID#:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 36° 48.6' N ( 36.81000) LONGITUDE: 121° 47.1' W (-121.78500)
The bench mark is a disk set in a concrete pad 76.2 m (250 ft) SSW of the WNW of
NW corner of the Highway 1 bridge over the slough, 7.16 m (23.5 ft) ENE of the
center of the main door to Skippers Restaurant, 1.31 m (4.3 ft) NNE of fence
post on the south side of the sidewalk, and 0.18 m (0.6 ft) from the south edge
of the sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 9413623 PUBLICATION DATE: 01/06/2004
Name: ELKHORN SLOUGH, ENTRANCE BRIDGE
CA
NOAA Chart: 18685 Latitude: 36° 48.6' N ( 36.81000)
USGS Quad: MOSS LANDING Longitude: 121° 47.1' W (-121.78500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 941 3623 B 1976
ALIAS: UNSTAMPED, TBM 16
MONUMENTATION: Chiseled Square VM#: 8062
AGENCY: California State Lands Commission IDB PID#:
SETTING CLASSIFICATION: Retaining wall OPUS PID:
LATITUDE: 36° 48.6' N ( 36.81000) LONGITUDE: 121° 47.1' W (-121.78500)
The bench mark is a square chiseled in the top of a concrete bridge retaining
wall along Highway 1, at the NE corner of Highway bridge over the slough and 0.7
km (0.45 mi) north of Dolan Road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 9413623 PUBLICATION DATE: 01/06/2004
Name: ELKHORN SLOUGH, ENTRANCE BRIDGE
CA
NOAA Chart: 18685 Latitude: 36° 48.6' N ( 36.81000)
USGS Quad: MOSS LANDING Longitude: 121° 47.1' W (-121.78500)
T I D A L D A T U M S
Tidal datums at ELKHORN SLOUGH, ENTRANCE BRIDGE based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: May 1977 - June 1977
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9413450 MONTEREY, MONTEREY HARBOR
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.609
MEAN HIGH WATER MHW = 1.399
MEAN TIDE LEVEL MTL = 0.862
MEAN SEA LEVEL MSL = 0.837
MEAN LOW WATER MLW = 0.325
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
3623 A 1976 2.581 1.182
3623 C 1976 2.039 0.640
3623 D 1976 2.297 0.898
3623 E 1976 3.176 1.777
PURPLE 1972 2.539 1.140
941 3623 B 1976 3.350 1.951
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 9413623 PUBLICATION DATE: 01/06/2004
Name: ELKHORN SLOUGH, ENTRANCE BRIDGE
CA
NOAA Chart: 18685 Latitude: 36° 48.6' N ( 36.81000)
USGS Quad: MOSS LANDING Longitude: 121° 47.1' W (-121.78500)
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.