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Bench Mark Sheet for 9418799, FRESHWATER 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  5

                                                                                
Station ID: 9418799                         PUBLICATION DATE:  04/01/2004
Name:       FRESHWATER SLOUGH, HUMBOLDT BAY                   
            CA
NOAA Chart: 18622                           Latitude:   40° 47.9' N (  40.79830)
USGS Quad:  EUREKA                          Longitude: 124°  7.2' W (-124.12000)


To reach the tidal bench marks from Eureka, proceed east along US Highway 101 to
the Myrtle Avenue exit, then proceed SE along Myrtle Avenue for 2.01 km (1.25
mi), then turn left and proceed east on Park Street until it dead ends.  The
bench marks are located along Park Street.  The tide gage and staff were on the
wooden bridge over the slough.


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


                 PRIMARY BENCH MARK STAMPING:  8799 A 1978
                         DESIGNATION:          941 8799 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8728
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  LV0643
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 47.7' N (  40.79500)          LONGITUDE: 124°  7.3' W (-124.12200)


The primary bench mark is a disk located 62 m (203 ft) SW of SW corner of a
wooden bridge, 4 m (13 ft) north of centerline of Park Street, and 1 m (2 ft) SW
of corner of wooden fence.  The bench mark is crimped to the the top of a
galvanized steel rod driven 17.1 m (56 ft), and encased in concrete and a PVC
pipe extending 15 cm (0.5 ft) above grade.

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

                                                                                
Station ID: 9418799                         PUBLICATION DATE:  04/01/2004
Name:       FRESHWATER SLOUGH, HUMBOLDT BAY                   
            CA
NOAA Chart: 18622                           Latitude:   40° 47.9' N (  40.79830)
USGS Quad:  EUREKA                          Longitude: 124°  7.2' W (-124.12000)


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


                         BENCH MARK STAMPING:  8799 B 1978
                         DESIGNATION:          941 8799 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8729
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 47.8' N (  40.79670)          LONGITUDE: 124°  7.1' W (-124.11800)


The bench mark is a disk located 114 m (375 ft) west of east end of Park Street,
9 m (31 ft) SSW of SW corner of large garage, 2 m (8 ft) south of centerline of
Park Street, and 1 m (3 ft) east of a witness post.  The bench mark is crimped
to the top of a galvanized steel rod driven 13.7 m (45 ft) and encased in
concrete and a PVC pipe extending 0.21 m (0.7 ft) above grade.



                         BENCH MARK STAMPING:  8799 C 1978
                         DESIGNATION:          941 8799 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8730
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 47.8' N (  40.79670)          LONGITUDE: 124°  7.1' W (-124.11800)


The bench mark is a disk located 198 m (650 ft) east along Park Street from
center of intersection of Park and Quakes Streets, 11 m (36 ft) east of
centerline of dirt driveway, 3.81 m (12.5 ft) SSW of centerline of Park Street,
and 1 m (2 ft) ESE of witness post.  The bench mark is crimped to the top of a
galvanized steel rod driven 9.5 m (31 ft) and encased in concrete and a PVC pipe
extending 12 cm (0.4 ft) above grade.

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

                                                                                
Station ID: 9418799                         PUBLICATION DATE:  04/01/2004
Name:       FRESHWATER SLOUGH, HUMBOLDT BAY                   
            CA
NOAA Chart: 18622                           Latitude:   40° 47.9' N (  40.79830)
USGS Quad:  EUREKA                          Longitude: 124°  7.2' W (-124.12000)


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


                         BENCH MARK STAMPING:  8799 E 1978
                         DESIGNATION:          941 8799 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8731
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  LV0642
SETTING CLASSIFICATION:  Sidewalk                              OPUS PID#: LV0642
LATITUDE:   40° 47.7' N (  40.79500)          LONGITUDE: 124°  7.6' W (-124.12700)


The bench mark is a disk set flush in the NE corner of sidewalk at the SW corner
of the T intersection of Park and Quaker Streets, 11 m (37 ft) SW of center of
intersection, and 3 m (11 ft) east of the fire hydrant.

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

                                                                                
Station ID: 9418799                         PUBLICATION DATE:  04/01/2004
Name:       FRESHWATER SLOUGH, HUMBOLDT BAY                   
            CA
NOAA Chart: 18622                           Latitude:   40° 47.9' N (  40.79830)
USGS Quad:  EUREKA                          Longitude: 124°  7.2' W (-124.12000)


                            T I D A L   D A T U M S 


Tidal datums at FRESHWATER SLOUGH, HUMBOLDT BAY based on:

     LENGTH OF SERIES:      8 MONTHS
     TIME PERIOD:           May 1978 - December 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   =  2.162
     MEAN HIGH WATER                            MHW    =  1.943
     MEAN TIDE LEVEL                            MTL    =  1.137
     MEAN SEA LEVEL                             MSL    =  1.111
     MEAN LOW WATER                             MLW    =  0.332
     North American Vertical Datum              NAVD88 =  0.138
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     8799 A 1978                                 2.913    0.970
     8799 B 1978                                 2.371    0.428
     8799 C 1978                                 5.365    3.422
     8799 E 1978                                20.639   18.696


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

                                                                                
Station ID: 9418799                         PUBLICATION DATE:  04/01/2004
Name:       FRESHWATER SLOUGH, HUMBOLDT BAY                   
            CA
NOAA Chart: 18622                           Latitude:   40° 47.9' N (  40.79830)
USGS Quad:  EUREKA                          Longitude: 124°  7.2' W (-124.12000)


                             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 9418799 FRESHWATER SLOUGH, HUMBOLDT BAY, CA

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