Superseded Bench Mark Sheet for 9418817, Samoa, Humboldt Bay CA

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                   PUBLICATION DATE:  09/29/2000
Station ID: 9418817                                SUPERCEDED DATE:   04/21/2003
Name:       SAMOA,HUMBOLDT BAY                                
            CALIFORNIA
NOAA Chart: 18662                                  Latitude:         40° 49.6' N
USGS Quad:  EUREKA                                 Longitude:       124° 10.8' W


To reach the tidal bench marks from U. S. Highway 101 in Eureka, exit at Highway
255, continue 3.2 Km (2 mi) west until a T intersection, turn left and travel
2.8 Km (1.7 mi).  Turn left on L-P Blvd, at T intersection turn left, then right
at first stop sign to Lousiana-Pacific main gate (No. 6).  Continue to flashing
red light, left and stay on road until after it curves to right, and 46 m (150
ft) after the curve veer to the right.  The bench marks are located in the
vicinity, and the tide gauge and staff were located on the inside corner of
north end of dock.


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


                 PRIMARY BENCH MARK STAMPING:  8817 B 1978
                         DESIGNATION:          941 8817 B

MONUMENTATION:           Tidal Station disk                        VM#:    11961
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Galvanized steel rod


The Primary bench mark is a disk located 3.51 m (11.5 ft) NNE of an electric
gate opener at Lousiana-Pacific gate #2. The bench mark is set 0.06 m (0.2 ft)
below grade, crimped to a galvanized rod driven 19.2 m (63 ft) to refusal, and
encased in concrete and white PVC pipe.



                         BENCH MARK STAMPING:  NO 2 1962
                         DESIGNATION:          941 8817 TIDAL 2

MONUMENTATION:           Tidal Station disk                        VM#:    11960
AGENCY:                  US Coast & Geodetic Survey (USC&GS)       PID#:  LV0352
SETTING CLASSIFICATION:  Concrete foundation


The bench mark is a disk set in top of an unused concrete filter screen, due
south of a large green metal water tank, due NE of wooden water tower, 82 m (270
ft) NW of shore end of north dock at the Lousiana-Pacific lumber mill, and 1 m
(3 ft) NW of SE corner of concrete housing.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                   PUBLICATION DATE:  09/29/2000
Station ID: 9418817                                SUPERCEDED DATE:   04/21/2003
Name:       SAMOA,HUMBOLDT BAY                                
            CALIFORNIA
NOAA Chart: 18662                                  Latitude:         40° 49.6' N
USGS Quad:  EUREKA                                 Longitude:       124° 10.8' W


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


                         BENCH MARK STAMPING:  8817 C 1978
                         DESIGNATION:          941 8817 C

MONUMENTATION:           Tidal Station disk                        VM#:    11962
AGENCY:                  National Ocean Service (NOS)              PID:         
SETTING CLASSIFICATION:  Galvanized steel rod


The bench mark is a disk located 0.2 km (0.1 mi) ENE of centerline of an
intersection of Old Samoa Road and road leading to Lousiana-Pacific gate # 2, 21
m (70 ft) NW of an intersection of private road and railroad tracks, 7 m (24 ft)
SSE of centerline of Old Samoa Road, 4 m (14 ft) NNW of west rail of railroad
tracks.  The bench mark is set below grade, crimped to a galvanized rod driven
to 20.7 m (68 ft), and enclosed in concrete and white PVC pipe.



                         BENCH MARK STAMPING:  F 735 1944
                         DESIGNATION:          F 735

MONUMENTATION:           Tidal Station disk                        VM#:    11963
AGENCY:                  US Coast & Geodetic Survey (USC&GS)       PID#:  LV0351
SETTING CLASSIFICATION:  Concrete monument


The bench mark is a disk set on concrete monument located 39 m (128 ft) west of
a power pole with guy wires, 7 m (24 ft) north of centerline of Old Samoa Road,
1 m (3 ft) south of a point directly under a cable line, 0.61 m (2.0 ft) east of
a witness post, and set level with ground in top of a concrete post projecting
0.06 m (0.2 ft) above ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                   PUBLICATION DATE:  09/29/2000
Station ID: 9418817                                SUPERCEDED DATE:   04/21/2003
Name:       SAMOA,HUMBOLDT BAY                                
            CALIFORNIA
NOAA Chart: 18662                                  Latitude:         40° 49.6' N
USGS Quad:  EUREKA                                 Longitude:       124° 10.8' W


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


                         BENCH MARK STAMPING:  Z 109 1967
                         DESIGNATION:          Z 1091

MONUMENTATION:           Tidal Station disk                        VM#:    11964
AGENCY:                  US Coast & Geodetic Survey (USC&GS)       PID#:  LV0350
SETTING CLASSIFICATION:  Copper-clad steel rod


The bench mark is a disk located 13 m (42 ft) west of centerline of a road, 0.3
m (1 ft) north of a power pole with guy wire, and 0.3 m (1 ft) south of a
witness post. The bench mark is set 0.3 m (1 ft) above ground, crimped to a
copper-clad rod driven to refusal at 37.5 m (123  ft), and encased in a concrete
post projecting 0.1 m (0.3 ft) above ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                   PUBLICATION DATE:  09/29/2000
Station ID: 9418817                                SUPERCEDED DATE:   04/21/2003
Name:       SAMOA,HUMBOLDT BAY                                
            CALIFORNIA
NOAA Chart: 18662                                  Latitude:         40° 49.6' N
USGS Quad:  EUREKA                                 Longitude:       124° 10.8' W


                            T I D A L   D A T U M S 


Tidal datums at SAMOA,HUMBOLDT BAY based on:

     LENGTH OF SERIES:      7 MONTHS
     TIME PERIOD:           May 1978 - January 1979
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  9418767 NORTH SPIT, HUMBOLDT BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.257
     MEAN HIGH WATER                            MHW    =  2.039
     MEAN SEA LEVEL                             MSL    =  1.235
     MEAN TIDE LEVEL                            MTL    =  1.216
     MEAN LOW WATER                             MLW    =  0.394
     North American Vertical Datum              NAVD88 =  0.217
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     8817 B 1978                                 5.612    3.573
     NO 2 1962                                   3.470    1.431
     8817 C 1978                                 5.266    3.227
     F 735 1944                                  5.315    3.276
     Z 109 1967                                  4.959    2.920


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

                                                   PUBLICATION DATE:  09/29/2000
Station ID: 9418817                                SUPERCEDED DATE:   04/21/2003
Name:       SAMOA,HUMBOLDT BAY                                
            CALIFORNIA
NOAA Chart: 18662                                  Latitude:         40° 49.6' N
USGS Quad:  EUREKA                                 Longitude:       124° 10.8' W


                             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 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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