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Bench Mark Sheet for 9448558, LA CONNER, SWINOMISH SLOUGH WA

Superseded Epoch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Small blue map location marker Unpublished bench mark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.

Error: There is no bench mark map available for 9448558 LA CONNER, SWINOMISH SLOUGH, WA
Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  8

                                                                                
Station ID: 9448558                                PUBLICATION DATE:  07/15/2004
Name:       LA CONNER, SWINOMISH SLOUGH                       
            WA
NOAA Chart: 18427                                  Latitude:         48° 23.5' N
USGS Quad:  LA CONNER                              Longitude:       122° 29.8' W


To reach the tidal bench marks from Mount Vernon, proceed west on State Highway
536 for 10 km (6 mi) to Best Road, then turn left and proceed south on Best Road
for 6 km (4 mi), then turn right and proceed west on Chillberg Road (which
becomes Morris Street) for 3 km (2 mi) to the end of the street in the town of
La Conner.  The bench marks are located at the library, post office, and Conner
Park.  The tide gage and staff were located at the wharf beside Channel Boat
House.


                         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  8

                                                                                
Station ID: 9448558                                PUBLICATION DATE:  07/15/2004
Name:       LA CONNER, SWINOMISH SLOUGH                       
            WA
NOAA Chart: 18427                                  Latitude:         48° 23.5' N
USGS Quad:  LA CONNER                              Longitude:       122° 29.8' W


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


                 PRIMARY BENCH MARK STAMPING:  3 1935
                         DESIGNATION:          TIDAL 3

MONUMENTATION:           Bench Mark disk                           VM#:     9253
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID#:  TR0236
SETTING CLASSIFICATION:  Rock outcrop


The primary bench mark is a disk set in the top of the lower of two natural
steps in a large rock outcrop on the south side of Washington Street between
First and Second Streets, 41 m (135 ft) east of the intersection of First and
Washington Streets, 29 m (94 ft) east of the SE curb of First Street, 1.37 m
(4.5 ft) south of a path leading uphill from First Street, and 5 m (15 ft) above
the level of First Street.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  8

                                                                                
Station ID: 9448558                                PUBLICATION DATE:  07/15/2004
Name:       LA CONNER, SWINOMISH SLOUGH                       
            WA
NOAA Chart: 18427                                  Latitude:         48° 23.5' N
USGS Quad:  LA CONNER                              Longitude:       122° 29.8' W


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


                         BENCH MARK STAMPING:  TIDAL 4 RESET 1967
                         DESIGNATION:          TIDAL 4 RESET

MONUMENTATION:           Tidal Station disk                        VM#:     9255
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID:         
SETTING CLASSIFICATION:  Concrete foundation


The bench mark is a disk set in the SE corner of a concrete foundation for four
storage tanks of the Chevron Oil Company, 61 m (200 ft) NE of the centerline of
the intersection of Third and Morris Streets, 27 m (90 ft) south of the
centerline of Crater Street, 16.61 m (54.5 ft) NW of the NW corner of Chevron
Service Station, 5.64 m (18.5 ft) north of the SE corner of a low concrete wall
surrounding a group of oil storage tanks, and 0.46 m (1.5 ft) east of the east
concrete wall.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  8

                                                                                
Station ID: 9448558                                PUBLICATION DATE:  07/15/2004
Name:       LA CONNER, SWINOMISH SLOUGH                       
            WA
NOAA Chart: 18427                                  Latitude:         48° 23.5' N
USGS Quad:  LA CONNER                              Longitude:       122° 29.8' W


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


                         BENCH MARK STAMPING:  TIDAL 6 1972
                         DESIGNATION:          TIDAL 6

MONUMENTATION:           Tidal Station disk                        VM#:     9256
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID:         
SETTING CLASSIFICATION:  Rock outcrop


The bench mark is a disk set in a rock outcrop near the library between First
and Second Streets, 2.10 m (6.9 ft) SE of the NE corner of the library, and 1.07
m (3.5 ft) above the ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  8

                                                                                
Station ID: 9448558                                PUBLICATION DATE:  07/15/2004
Name:       LA CONNER, SWINOMISH SLOUGH                       
            WA
NOAA Chart: 18427                                  Latitude:         48° 23.5' N
USGS Quad:  LA CONNER                              Longitude:       122° 29.8' W


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


                         BENCH MARK STAMPING:  TIDAL 7 1972
                         DESIGNATION:          TIDAL 7

MONUMENTATION:           Tidal Station disk                        VM#:     9257
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID:         
SETTING CLASSIFICATION:  Concrete loading ramp


The bench mark is a disk set in the NE corner of the concrete loading ramp of
the U.S. Post Office on First Street, 34 m (113 ft) NNW of the intersection of
Washington and Second Streets, 0.40 m (1.3 ft) west of the NE corner of the
building, and 0.76 m (2.5 ft) above the parking lot.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  8

                                                                                
Station ID: 9448558                                PUBLICATION DATE:  07/15/2004
Name:       LA CONNER, SWINOMISH SLOUGH                       
            WA
NOAA Chart: 18427                                  Latitude:         48° 23.5' N
USGS Quad:  LA CONNER                              Longitude:       122° 29.8' W


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


                         BENCH MARK STAMPING:  TIDAL 8 1972
                         DESIGNATION:          TIDAL 8

MONUMENTATION:           Tidal Station disk                        VM#:     9258
AGENCY:                  US Coast and Geodetic Survey (USC&GS)     PID:         
SETTING CLASSIFICATION:  Bedrock


The bench mark is a disk set in bedrock on the north edge of Conner Park, 29 m
(95 ft) WSW of the intersection of Washington and Second Streets, 10 m (34 ft)
SE of the centerline of Washington Street, 5 m (18 ft) north of a trail through
the park, and 1 m (3 ft) below the trail.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  8

                                                                                
Station ID: 9448558                                PUBLICATION DATE:  07/15/2004
Name:       LA CONNER, SWINOMISH SLOUGH                       
            WA
NOAA Chart: 18427                                  Latitude:         48° 23.5' N
USGS Quad:  LA CONNER                              Longitude:       122° 29.8' W


                            T I D A L   D A T U M S 


Tidal datums at LA CONNER, SWINOMISH SLOUGH based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           December 1972 - January 1973
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9447130 SEATTLE, PUGET SOUND


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

     MEAN HIGHER HIGH WATER                     MHHW   =  3.154
     MEAN HIGH WATER                            MHW    =  2.874
     MEAN TIDE LEVEL                            MTL    =  1.848
     MEAN SEA LEVEL                             MSL    =  1.817
     MEAN LOW WATER                             MLW    =  0.822
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     3 1935                                      7.638    4.764
     TIDAL 4 RESET 1967                          3.171    0.297
     TIDAL 6 1972                                5.250    2.376
     TIDAL 7 1972                                4.030    1.156
     TIDAL 8 1972                                7.146    4.272


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  8 of  8

                                                                                
Station ID: 9448558                                PUBLICATION DATE:  07/15/2004
Name:       LA CONNER, SWINOMISH SLOUGH                       
            WA
NOAA Chart: 18427                                  Latitude:         48° 23.5' N
USGS Quad:  LA CONNER                              Longitude:       122° 29.8' 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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Revised: 10/15/2013
NOAA / National Ocean Service
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