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Bench Mark Sheet for 9418802, EUREKA SLOUGH, HUMBOLDT 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9418802                         PUBLICATION DATE:  05/07/2003
Name:       EUREKA SLOUGH, HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 48.4' N (  40.80670)
USGS Quad:  EUREKA                          Longitude: 124°  8.5' W (-124.14200)


To reach the tidal bench marks from the intersection of Fourth Street (US
Highway 101 South) and X Street, proceed north on X Street for 0.3 km (0.2 mi),
then turn right onto First Street and proceed east to a fork in the road, then
take the left fork and cross over the Northwest Pacific railroad tracks.  The
bench marks are located between and along First and Fourth Streets.  The tide
station was located on the south side of the Northwest Pacific railroad bridge
over the slough.


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


                 PRIMARY BENCH MARK STAMPING:  8802 B 1978
                         DESIGNATION:          941 8802 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8739
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  LV0639
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 48.4' N (  40.80670)          LONGITUDE: 124°  8.6' W (-124.14300)


The primary bench mark is a disk located on the south fork at the east end of
First Street, 26 m (85 ft) SW of SW corner of Northwest Pacific railroad bridge
over the slough, 15.51 m (50.9 ft) SSW of the south rail, 5 m (16 ft) SSW of the
Northwest Pacific railroad access road centerline, and 2.99 m (9.8 ft) NNW of a
utility pole.  The mark is crimped to the top of a galvanized steel rod, driven
11.6 m (38 ft) to refusal, and encased in a 4-inch PVC pipe with concrete
kickblock.

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

                                                                                
Station ID: 9418802                         PUBLICATION DATE:  05/07/2003
Name:       EUREKA SLOUGH, HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 48.4' N (  40.80670)
USGS Quad:  EUREKA                          Longitude: 124°  8.5' W (-124.14200)


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


                         BENCH MARK STAMPING:  8802 A 1978
                         DESIGNATION:          941 8802 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8738
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  LV0640
SETTING CLASSIFICATION:  Concrete pier                         OPUS PID:        
LATITUDE:   40° 48.4' N (  40.80670)          LONGITUDE: 124°  8.6' W (-124.14300)


The bench mark is a disk in set in the top of a concrete pier at the west end of
the Northwest Pacific railroad lift span over the slough, 35.51 m (116.5 ft)
east of the west end of the bridge, 1.4 m (4.6 ft) south of the near rail, and
2.1 m (6.9 ft) below the rails.



                         BENCH MARK STAMPING:  8802 C 1978
                         DESIGNATION:          941 8802 C

MONUMENTATION:           Tidal Station disk                    VM#:         8740
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 48.4' N (  40.80670)          LONGITUDE: 124°  8.5' W (-124.14200)


The bench mark is a disk located 31 m (101.7 ft) NW of the NW corner of the
Pepsi bottling plant at the NW corner of Second and Y Streets, 11 m (36 ft) SSW
of the south rail, 2.5 m (8.2 ft) SSW of centerline of Northwest Pacific
railroad access road, and 1 m (3.3 ft) east of a witness post. The mark is
crimped to the top of a galvanized steel rod, driven 12.5 m (41 ft) to refusal,
and encased in a 4-inch PVC pipe and concrete kickblock.

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

                                                                                
Station ID: 9418802                         PUBLICATION DATE:  05/07/2003
Name:       EUREKA SLOUGH, HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 48.4' N (  40.80670)
USGS Quad:  EUREKA                          Longitude: 124°  8.5' W (-124.14200)


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


                         BENCH MARK STAMPING:  8802 D 1978
                         DESIGNATION:          941 8802 D

MONUMENTATION:           Tidal Station disk                    VM#:         8741
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 48.4' N (  40.80670)          LONGITUDE: 124°  8.5' W (-124.14200)


The bench mark is a disk located 23 m (75 ft) ESE of center of intersection of X
and First Streets, and 0.49 m (1.6 ft) south of a steel gate post.  The mark is
crimped to the top of a galvanized steel rod driven 14 m (46 ft) to refusal, and
encased in PVC pipe and concrete.

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

                                                                                
Station ID: 9418802                         PUBLICATION DATE:  05/07/2003
Name:       EUREKA SLOUGH, HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 48.4' N (  40.80670)
USGS Quad:  EUREKA                          Longitude: 124°  8.5' W (-124.14200)


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


                         BENCH MARK STAMPING:  J 75 1931 RESET 1942
                         DESIGNATION:          J 75 RESET

MONUMENTATION:           Bench Mark disk                       VM#:         8742
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  LV0287
SETTING CLASSIFICATION:  Concrete curb on bridge               OPUS PID:        
LATITUDE:   40° 48.3' N (  40.80500)          LONGITUDE: 124°  8.5' W (-124.14200)


The bench mark is a disk set in top of the SE end of the concrete curb of bridge
4-22 over the slough, 1.8 km (1.1 mi) east along U.S. Highway 101 from the post
office at Highway Marker 79.78, 4.27 m (14.0 ft) SE of centerline of SE lanes of
highway, 1.52 m (5.0 ft) NE of SW end of curb, and 0.15 m (0.5 ft) above the
highway.



                         BENCH MARK STAMPING:  W 1087 1967 RESET 1969
                         DESIGNATION:           W 1087 RESET

MONUMENTATION:           Bench Mark disk                       VM#:         8743
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  LV0289
SETTING CLASSIFICATION:  Culvert head wall                     OPUS PID:        
LATITUDE:   40° 48.3' N (  40.80500)          LONGITUDE: 124°  7.6' W (-124.12700)


The bench mark is a disk set in top of a culvert headwall, 1.1 km (0.7 mi) north
of highway bridge over the slough at milepost 80.57, and 13 m (43 ft) east of
the white strip for the northbound lanes.

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

                                                                                
Station ID: 9418802                         PUBLICATION DATE:  05/07/2003
Name:       EUREKA SLOUGH, HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 48.4' N (  40.80670)
USGS Quad:  EUREKA                          Longitude: 124°  8.5' W (-124.14200)


                            T I D A L   D A T U M S 


Tidal datums at EUREKA SLOUGH, HUMBOLDT BAY based on:

     LENGTH OF SERIES:      6 MONTHS
     TIME PERIOD:           April 1978 - September 1978
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9419750 CRESCENT CITY, PACIFIC OCEAN


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.253
     MEAN HIGH WATER                            MHW    =  2.029
     MEAN SEA LEVEL                             MSL    =  1.211
     MEAN TIDE LEVEL                            MTL    =  1.210
     MEAN LOW WATER                             MLW    =  0.391
     North American Vertical Datum              NAVD88 =  0.235
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     8802 B 1978                                 4.077    2.048
     8802 A 1978                                 3.085    1.056
     8802 C 1978                                 3.253    1.224
     8802 D 1978                                 3.456    1.427
     J 75 1931 RESET 1942                        7.933    5.904
     W 1087 1967 RESET 1969                      2.045    0.016


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

                                                                                
Station ID: 9418802                         PUBLICATION DATE:  05/07/2003
Name:       EUREKA SLOUGH, HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 48.4' N (  40.80670)
USGS Quad:  EUREKA                          Longitude: 124°  8.5' W (-124.14200)


                             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 9418802 EUREKA SLOUGH, HUMBOLDT BAY, CA

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