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Bench Mark Sheet for 9415228, INVERNESS, TOMALES BAY CA

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                                                
Station ID: 9415228                         PUBLICATION DATE:  08/18/2010
Name:       INVERNESS, TOMALES BAY                            
            CA
NOAA Chart: 18643                           Latitude:   38°  6.8' N (  38.11330)
USGS Quad:  INVERNESS                       Longitude: 122° 52.1' W (-122.86800)


To reach the tidal bench marks from Point Reyes, proceed NW along Sir Francis
Drake Boulevard and follow the along west side of Tomales Bay to Teachers Beach,
just north of the Inverness Yacht Club.  The bench marks are along the perimeter
of the sandy beach seaward of the steep cliffs above the beach.  The tide gage
and staff were located on the outer part of the longer of two adjacent private
piers.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  5228 A 1979
                         DESIGNATION:          941 5228 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8620
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Set in a sloping outcrop              OPUS PID:        
LATITUDE:   38°  6.8' N (  38.11330)          LONGITUDE: 122° 52.1' W (-122.86800)


The bench mark is a disk set horizontally in a sloping outcrop at the west end
of a small wooden bulkhead, 42.06 m (138.0 ft) NW of bench mark 5228 B 1979, 4 m
(13 ft) SE of the corner of the dock at 172 Camino del Mar, 4 m (13 ft) east of
the east corner of the wooden stairway at the beach, and 0.91 m (3.0 ft) NE of
the cliff.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 9415228                         PUBLICATION DATE:  08/18/2010
Name:       INVERNESS, TOMALES BAY                            
            CA
NOAA Chart: 18643                           Latitude:   38°  6.8' N (  38.11330)
USGS Quad:  INVERNESS                       Longitude: 122° 52.1' W (-122.86800)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  NO 3 1931
                         DESIGNATION:          941 5228 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         8618
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  JT0913
SETTING CLASSIFICATION:  Set in top of stone wall              OPUS PID:        
LATITUDE:   38°  6.1' N (  38.10170)          LONGITUDE: 122° 51.4' W (-122.85700)


The primary bench mark is a disk set in top of and in center of the stone wall
on the west side of the county road, at the T-junction of a private driveway
leading SW to a two-story frame house, 152.40 m (500.0 ft) south of the yacht
club dock, 20.27 m (66.5 ft) SW of the centerline of the highway, 11.58 m (38.0
ft) south of the extreme north end of the wall, 11.28 m (37.0 ft) NW of the
centerline of the driveway, 9.45 m (31.0 ft) north of an iron gate, 6 m (21 ft)
south of mileage marker A 109 28-75, and 0.76 m (2.5 ft) above the ground.



                         BENCH MARK STAMPING:  5228 C 1979
                         DESIGNATION:          941 5228 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8622
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Set in a ledge on the cliff           OPUS PID:        
LATITUDE:   38°  6.8' N (  38.11330)          LONGITUDE: 122° 52.1' W (-122.86800)


The bench mark is a disk set horizontally in a ledge on the cliff, 150.0 m
(492.0 ft) SSE of the east end of the dock at 172 Camino del Mar, 102.11 m
(335.0 ft) NW of the dock at 98 Camino del Mar, 58.83 m (193.0 ft) NNW of bench
mark 5228 D 1979, 8.84 m (29.0 ft) WNW of a private survey marker copper in a
concrete post, and 0.6 m (2 ft) below the shoreline.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                                                
Station ID: 9415228                         PUBLICATION DATE:  08/18/2010
Name:       INVERNESS, TOMALES BAY                            
            CA
NOAA Chart: 18643                           Latitude:   38°  6.8' N (  38.11330)
USGS Quad:  INVERNESS                       Longitude: 122° 52.1' W (-122.86800)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  5228 D 1979
                         DESIGNATION:          941 5228 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8623
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Set in a jutting part of the cliff    OPUS PID:        
LATITUDE:   38°  6.8' N (  38.11330)          LONGITUDE: 122° 52.1' W (-122.86800)


The bench mark is a disk set horizontally in a jutting part of the cliff, 206.65
m (678.0 ft) SE of the east end of the pier at 172 Camino del Mar, 58.83 m
(193.0 ft) SSE of bench mark 5228 C 1979, 43.89 m (144.0 ft) WNW of the dock at
98 Camino del Mar, 32.92 m (108.0 ft) SW of bench mark 5228 E 1979, 0.91 m (3.0
ft) east of the cliff, and 0.61 m (2.0 ft) below the shoreline on the cliff.



                         BENCH MARK STAMPING:  5228 E 1979
                         DESIGNATION:          941 5228 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8624
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Sloping outcrop                       OPUS PID:        
LATITUDE:   38°  6.8' N (  38.11330)          LONGITUDE: 122° 52.1' W (-122.86800)


The bench mark is a disk set horizontally in the top of a sloping outcrop, 32.91
m (108.0 ft) NE of bench mark 5228 D 1979, 10.67 m (35.0 ft) WNW of the dock at
98 Camino del Mar, 2.44 m (8.0 ft) ENE of the edge of the cliff, and 0.76 m (2.5
ft) below the shoreline.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                                                
Station ID: 9415228                         PUBLICATION DATE:  08/18/2010
Name:       INVERNESS, TOMALES BAY                            
            CA
NOAA Chart: 18643                           Latitude:   38°  6.8' N (  38.11330)
USGS Quad:  INVERNESS                       Longitude: 122° 52.1' W (-122.86800)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  TEACHERS 1967
                         DESIGNATION:          TEACHERS

MONUMENTATION:           Survey disk                           VM#:        15720
AGENCY:                  California State Land Commission      IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   38°  6.8' N (  38.11330)          LONGITUDE: 122° 52.1' W (-122.86800)


The bench mark is a disk set in a rock outcrop at the water's edge (submerged at
high tide), lying approximately 126 m (413 ft) north of the southern end of the
first wooden pier south of the mark, at the northern end of a cove known as
Teachers Beach, and 8 m (25 ft) NE of a rock outcrop along the point (see bench
mark sketch) of the beach.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                                                
Station ID: 9415228                         PUBLICATION DATE:  08/18/2010
Name:       INVERNESS, TOMALES BAY                            
            CA
NOAA Chart: 18643                           Latitude:   38°  6.8' N (  38.11330)
USGS Quad:  INVERNESS                       Longitude: 122° 52.1' W (-122.86800)


                            T I D A L   D A T U M S 


Tidal datums at INVERNESS, TOMALES BAY based on:

     LENGTH OF SERIES:      4 MONTHS
     TIME PERIOD:           October 1993 - January 1994
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9415020 POINT REYES, DRAKES BAY


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  1.725
     MEAN HIGH WATER                            MHW    =  1.500
     MEAN TIDE LEVEL                            MTL    =  0.908
     MEAN SEA LEVEL                             MSL    =  0.894
     MEAN LOW WATER                             MLW    =  0.316
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     5228 A 1979                                 1.838    0.338
     NO 3 1931                                   3.007    1.507
     5228 C 1979                                 1.628    0.128
     5228 D 1979                                 1.722    0.222
     5228 E 1979                                 1.535    0.035
     TEACHERS 1967                               1.359   -0.141


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  6

                                                                                
Station ID: 9415228                         PUBLICATION DATE:  08/18/2010
Name:       INVERNESS, TOMALES BAY                            
            CA
NOAA Chart: 18643                           Latitude:   38°  6.8' N (  38.11330)
USGS Quad:  INVERNESS                       Longitude: 122° 52.1' W (-122.86800)


                             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.

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Products available at 9415228 INVERNESS, TOMALES BAY, CA

Revised: 10/15/2013
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services