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Bench Mark Sheet for 9418686, HOOKTON 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9418686                         PUBLICATION DATE:  06/23/2003
Name:       HOOKTON SLOUGH,HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 41.2' N (  40.68670)
USGS Quad:  FIELDS LANDING                  Longitude: 124° 13.3' W (-124.22200)


To reach the tidal bench marks from US Highway 101 take Loleta-Hookton Exit
(about 16 km (10 mi) south of Eureka), along Salmon Creek Ranch access road
north (on west side of US Highway 101) until it curves sharply left, continue
straight through two ranch gates, left at third gate, right turn after 46 m (150
ft), follow levee SW until too narrow to be driven on, and then walk on north
side of small slough until you reach another slough (Hookton Slough). The gage
is located 91 m (300 ft) west SW of the point where you reach Hookton Slough. 
The tide gage and staff were located on a free standing pile in the slough.


                         T I D A L   B E N C H   M A R K S
                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 9418686                         PUBLICATION DATE:  06/23/2003
Name:       HOOKTON SLOUGH,HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 41.2' N (  40.68670)
USGS Quad:  FIELDS LANDING                  Longitude: 124° 13.3' W (-124.22200)


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


                 PRIMARY BENCH MARK STAMPING:  K 1087 1967
                         DESIGNATION:          K 1087

MONUMENTATION:           Bench Mark disk                       VM#:         8708
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  LV0255
SETTING CLASSIFICATION:  Concrete headwall of culvert          OPUS PID:        
LATITUDE:   40° 40.8' N (  40.68000)          LONGITUDE: 124° 12.1' W (-124.20200)


The primary bench mark is a disk set in top at south end of west concrete
headwall of culvert 68.80, 11.5 km (7.2 mi) north along US Highway 101 from
Fortuna overpass at Fortuna, 0.97 km (0.6 mi) north of Hookton Road overpass,
9.14 m (30.0 ft) west of centerline of west lanes of highway, and 0.76 m (2.5
ft) below the highway.



                         BENCH MARK STAMPING:  8686 A 1977
                         DESIGNATION:          941 8686 A

MONUMENTATION:           Tidal Station disk                    VM#:         8705
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   40° 41.2' N (  40.68670)          LONGITUDE: 124° 13.3' W (-124.22200)


The bench mark is a disk located 152 m (500 ft) SE of center of the slough,
12.19 m (40.0 ft) SE of junction of SE levee of slough and north drainage canal,
3.05 m (10.0 ft) NE of redwood witness post, and 1.07 m (3.5 ft) above grade (at
the top of north levee drainage canal).  The bench mark is crimped to the top of
a copper clad rod and set 0.08 m (0.25 ft) below grade, inside a PVC pipe (at
base of drainage canal levee).

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

                                                                                
Station ID: 9418686                         PUBLICATION DATE:  06/23/2003
Name:       HOOKTON SLOUGH,HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 41.2' N (  40.68670)
USGS Quad:  FIELDS LANDING                  Longitude: 124° 13.3' W (-124.22200)


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


                         BENCH MARK STAMPING:  8686 C 1977
                         DESIGNATION:          941 8686 C

MONUMENTATION:           Tidal Station disk                    VM#:         8706
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   40° 41.2' N (  40.68670)          LONGITUDE: 124° 13.3' W (-124.22200)


The bench mark is a disk located 0.72 km (0.45 mi) NW of bench mark K 1078 1967,
46 m (150 ft) west of south bound lanes of US Highway 101, 9.75 m (32.0 ft) NE
of center of McBride Ranch Road at turn in road, and 0.91 m (3.0 ft) SW of
telephone pole on west side of highway. The bench mark is crimped to the top of
a copper-clad rod, and set  0.08 m (0.25 ft) below grade, inside a PVC pipe.



                         BENCH MARK STAMPING:  8686 D 1977
                         DESIGNATION:          941 8686 D

MONUMENTATION:           Tidal Station disk                    VM#:         8707
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   40° 41.2' N (  40.68670)          LONGITUDE: 124° 13.3' W (-124.22200)


The bench mark is a disk located 0.24 km (0.15 mi) west of US Highway 101 at the
McBride Ranch equipment yard, 3.66 m (12.0 ft) south of center of Ranch Road,
and 0.61 m (2.0 ft)  west of NW corner of concrete building (dated 1923 above
door). The bench mark is crimped to the top of a copper-clad rod, set 0.15 m
(0.5 ft) below grade, inside a PVC pipe.

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

                                                                                
Station ID: 9418686                         PUBLICATION DATE:  06/23/2003
Name:       HOOKTON SLOUGH,HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 41.2' N (  40.68670)
USGS Quad:  FIELDS LANDING                  Longitude: 124° 13.3' W (-124.22200)


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


                         BENCH MARK STAMPING:   
                         DESIGNATION:          941 8686 NO STAMPING 1

MONUMENTATION:           Tidal Station disk                    VM#:         8709
AGENCY:                  Department of Interior (DOI)          IDB PID#:        
SETTING CLASSIFICATION:  Unspecified                           OPUS PID:        
LATITUDE:   40° 41.2' N (  40.68670)          LONGITUDE: 124° 13.3' W (-124.22200)


The bench mark is a disk located at the gate to west stock yard, west of gate at
end of McBride Ranch Road, 0.6 km (0.4 mi) WSW of west side of drainage ditch,
8.23 m (27.0 ft) east of concrete water trough, 4.57 m (15.0 ft) SW of gate past
the west side of drainage ditch, 0.08 m (0.25 ft) north of steel witness post,
and 0.15 m (0.5 ft) above grade.

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

                                                                                
Station ID: 9418686                         PUBLICATION DATE:  06/23/2003
Name:       HOOKTON SLOUGH,HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 41.2' N (  40.68670)
USGS Quad:  FIELDS LANDING                  Longitude: 124° 13.3' W (-124.22200)


                            T I D A L   D A T U M S 


Tidal datums at HOOKTON SLOUGH,HUMBOLDT BAY based on:

     LENGTH OF SERIES:      1 Year
     TIME PERIOD:           June 1978 - May 1979
     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   =  2.114
     MEAN HIGH WATER                            MHW    =  1.893
     MEAN SEA LEVEL                             MSL    =  1.147
     MEAN TIDE LEVEL                            MTL    =  1.135
     MEAN LOW WATER                             MLW    =  0.376
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     K 1087 1967                                 1.886   -0.007
     8686 A 1977                                 1.001   -0.892
     8686 C 1977                                 1.921    0.028
     8686 D 1977                                 1.665   -0.228
     941 8686 NO STAMPING 1                      1.172   -0.721


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

                                                                                
Station ID: 9418686                         PUBLICATION DATE:  06/23/2003
Name:       HOOKTON SLOUGH,HUMBOLDT BAY                       
            CA
NOAA Chart: 18622                           Latitude:   40° 41.2' N (  40.68670)
USGS Quad:  FIELDS LANDING                  Longitude: 124° 13.3' W (-124.22200)


                             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 9418686 HOOKTON SLOUGH,HUMBOLDT BAY, CA

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