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Bench Mark Sheet for 9418983, UPPER MAD RIVER SLOUGH 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Superseded Epoch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Small blue map location marker Unpublished bench mark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: 9418983                         PUBLICATION DATE:  03/09/2004
Name:       UPPER MAD RIVER SLOUGH                            
            CA
NOAA Chart: 18622                           Latitude:   40° 53.9' N (  40.89830)
USGS Quad:  ARCATA SOUTH                    Longitude: 124°  8.1' W (-124.13500)


To reach the tidal bench marks from the U.S. Highway 101 exit at Arcata/Samona
Boulevard west, then turn right on K Street which turns into Alliance Road and
proceed 1.6 km (1 mi) on Alliance Road until it ends at a T-intersection, then
turn left and proceed for 0.8 km (0.5 mi) to Lanphere Road, then turn left and
proceed west on Lanphere Road for 2.4 km (1.5 mi).  The bench marks are along
Lanphere Road east of the ranch buildings.  The tide gage and staff were located
on the south side of and at the midpoint of the bridge over the slough.


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


                 PRIMARY BENCH MARK STAMPING:  8983 A 1978
                         DESIGNATION:          941 8983 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8749
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 53.9' N (  40.89830)          LONGITUDE: 124°  8.1' W (-124.13500)


The primary bench mark is a disk located 9.14 m (30.0 ft) east of the east end
of the Lanphere Road bridge over the slough, 2.44 m (8.0 ft) south of the
centerline of Lanphere Road, 1.22 m (4.0 ft) east of a witness post/telephone
pole and 3 cm (0.1 ft) below grade.  The bench mark is crimped to the top of a
galvanized steel rod driven 9.8 m (32.0 ft) to refusal and encased in concrete.

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

                                                                                
Station ID: 9418983                         PUBLICATION DATE:  03/09/2004
Name:       UPPER MAD RIVER SLOUGH                            
            CA
NOAA Chart: 18622                           Latitude:   40° 53.9' N (  40.89830)
USGS Quad:  ARCATA SOUTH                    Longitude: 124°  8.1' W (-124.13500)


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


                         BENCH MARK STAMPING:  8983 B 1978
                         DESIGNATION:          941 8983 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8750
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 53.9' N (  40.89830)          LONGITUDE: 124°  8.1' W (-124.13500)


The bench mark is a disk located 113 m (370 ft) east of the east end of Lanphere
Road bridge over the slough, 28 m (92 ft) west of the second telephone pole east
of the east end of the bridge, 3.51 m (11.5 ft) south of the centerline of
Lanphere Road, 0.61 m (2.0 ft) north of a witness post, and 12 cm (0.4 ft) below
grade.  The bench mark is crimped to the top of a galvanized steel rod driven
9.8 m (32.0 ft) to refusal and encased in concrete.



                         BENCH MARK STAMPING:  8983 C 1978
                         DESIGNATION:          941 8983 C TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8751
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 53.9' N (  40.89830)          LONGITUDE: 124°  8.1' W (-124.13500)


The bench mark is a disk located 161 m (528 ft) east of the east end of Lanphere
Road bridge over the slough, 53.34 m (175.0 ft) WSW of the intersection of the
level dirt road and Lanphere Road, 7.62 m (25.0 ft) SW of a sign ONE LANE
BRIDGE, 3.05 m (10.0 ft) south of the centerline of Lanphere Road, 1.22 m (4.0
ft) north of a witness post, and 3 cm (0.1 ft) below grade.  The bench mark is
crimped to the top of a galvanized steel rod driven 11.6 m (38 ft) to refusal
and encased in concrete.

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

                                                                                
Station ID: 9418983                         PUBLICATION DATE:  03/09/2004
Name:       UPPER MAD RIVER SLOUGH                            
            CA
NOAA Chart: 18622                           Latitude:   40° 53.9' N (  40.89830)
USGS Quad:  ARCATA SOUTH                    Longitude: 124°  8.1' W (-124.13500)


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


                         BENCH MARK STAMPING:  8983 D 1978
                         DESIGNATION:          941 8983 D TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8752
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 53.9' N (  40.89830)          LONGITUDE: 124°  8.1' W (-124.13500)


The bench mark is a disk located 0.3 km (0.2 mi) east of the east end of the
Lanphere Road bridge over the slough, 15.54 m (51.0 ft) SE of the center of the
intersection of the levee dirt road and Lanphere Road, 5.79 m (19.0 ft) south of
the center of Lanphere Road, 0.76 m (2.5 ft) south of a witness post, and 3 cm
(0.1 ft) below grade.  The bench mark is crimped to the top of a galvanized
steel rod driven 16.5 m (54.0 ft) to refusal and encased in concrete and a PVC
pipe.



                         BENCH MARK STAMPING:  8983 E 1978
                         DESIGNATION:          941 8983 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         8753
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Galvanized steel rod                  OPUS PID:        
LATITUDE:   40° 53.9' N (  40.89830)          LONGITUDE: 124°  8.1' W (-124.13500)


The bench mark is a disk located 0.3 km (0.2 mi) east of the east end of the
Lanphere Road bridge over the slough, 18.29 m (60.0 ft) east of the fourth
telephone pole east of the east end of the bridge, 3.20 m (10.5 ft) south of the
centerline of Lanphere Road, 0.91 m (3.0 ft) north of a witness post, and 3 cm
(0.1 ft) below grade.  The bench mark is crimped to the top of a galvanized
steel rod driven 19.8 m (65.0 ft) to refusal and encased in concrete.

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

                                                                                
Station ID: 9418983                         PUBLICATION DATE:  03/09/2004
Name:       UPPER MAD RIVER SLOUGH                            
            CA
NOAA Chart: 18622                           Latitude:   40° 53.9' N (  40.89830)
USGS Quad:  ARCATA SOUTH                    Longitude: 124°  8.1' W (-124.13500)


                            T I D A L   D A T U M S 


Tidal datums at UPPER MAD RIVER SLOUGH based on:

     LENGTH OF SERIES:      5 MONTHS
     TIME PERIOD:           August 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   =  2.381
     MEAN HIGH WATER                            MHW    =  2.163
     MEAN SEA LEVEL                             MSL    =  1.343
     MEAN TIDE LEVEL                            MTL    =  1.281
     MEAN LOW WATER                             MLW    =  0.400
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     8983 A 1978                                 4.338    2.175
     8983 B 1978                                 3.304    1.141
     8983 C 1978                                 3.718    1.555
     8983 D 1978                                 3.910    1.747
     8983 E 1978                                 4.089    1.926


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

                                                                                
Station ID: 9418983                         PUBLICATION DATE:  03/09/2004
Name:       UPPER MAD RIVER SLOUGH                            
            CA
NOAA Chart: 18622                           Latitude:   40° 53.9' N (  40.89830)
USGS Quad:  ARCATA SOUTH                    Longitude: 124°  8.1' W (-124.13500)


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