Bench Mark Sheet for 8724292, KEMP CHANNEL VIADUCT FL

Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8724292                         PUBLICATION DATE:  05/28/2004
Name:       KEMP CHANNEL VIADUCT                              
            FL
NOAA Chart: 11448                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 28.1' W ( -81.46830)


To reach the tidal bench marks from the post office in Summerland Key, proceed
west on U.S. Highway 1 for 2.1 km (1.3 mi) to the west end of the bridge over
Kemp Channel.  The bench marks are located on the Cudjoe Key side of the old and
new highway bridges.  The tide gage and staff were located on the south side of
the west abutment of the old bridge, now used as a fishing pier.


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


                 PRIMARY BENCH MARK STAMPING:  NO 3 1937
                         DESIGNATION:          872 4292 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         6904
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0180
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 39.8' N (  24.66330)          LONGITUDE:  81° 28.0' W ( -81.46670)


The primary bench mark is a disk set flush in the NW concrete wing wall of the
old U.S. Highway 1 bridge (now used as a fishing pier), 8 m (26 ft) north of the
centerline of the old highway, and 1 m (4 ft) below the level of the old
highway.

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

                                                                                
Station ID: 8724292                         PUBLICATION DATE:  05/28/2004
Name:       KEMP CHANNEL VIADUCT                              
            FL
NOAA Chart: 11448                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 28.1' W ( -81.46830)


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


                         BENCH MARK STAMPING:  NO 1 1937
                         DESIGNATION:          872 4292 TIDAL 1

MONUMENTATION:           Tidal Station disk                    VM#:         6902
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0179
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 39.8' N (  24.66330)          LONGITUDE:  81° 28.0' W ( -81.46670)


The bench mark is a disk set flush in the SW concrete wing wall of the old U.S.
Highway 1 bridge (now used as a fishing pier), 19.96 m (65.5 ft) south of the
centerline of the old highway, 3 m (9 ft) east of the west end of the wing wall,
1 m (2 ft) west of the angle and inclined part of the wall, and 3 m (10 ft)
below the level of the old highway.



                         BENCH MARK STAMPING:  NO 2 1937
                         DESIGNATION:          872 4292 TIDAL 2

MONUMENTATION:           Tidal Station disk                    VM#:         6903
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  AA0178
SETTING CLASSIFICATION:  Concrete wing wall                    OPUS PID:        
LATITUDE:   24° 39.8' N (  24.66330)          LONGITUDE:  81° 28.0' W ( -81.46670)


The bench mark is a disk set flush in the SW concrete wing wall of the old U.S.
Highway 1 bridge (now used as a fishing pier), NNE of bench mark NO 1 1937, 5.03
m (16.5 ft) south of the centerline of the old highway, and 1 m (2 ft) below the
level of the old highway.

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

                                                                                
Station ID: 8724292                         PUBLICATION DATE:  05/28/2004
Name:       KEMP CHANNEL VIADUCT                              
            FL
NOAA Chart: 11448                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 28.1' W ( -81.46830)


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


                         BENCH MARK STAMPING:  4292 E 1982
                         DESIGNATION:          872 4292 E TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         6905
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0974
SETTING CLASSIFICATION:  Bridge abutment foundation            OPUS PID:        
LATITUDE:   24° 39.7' N (  24.66170)          LONGITUDE:  81° 28.1' W ( -81.46830)


The bench mark is a disk set flush in the concrete foundation for the west
bridge abutment located at the SW corner of the new U.S. Highway 1 bridge, 12.53
m (41.1 ft) WNW of the old highway bridge (now used as a fishing pier), 8.26 m
(27.1 ft) south of the centerline of U.S. Highway 1, 0.52 m (1.7 ft) east of the
cheekwall, and 2 m (6 ft) below highway level.



                         BENCH MARK STAMPING:  4292 D
                         DESIGNATION:          872 4292 D TIDAL

MONUMENTATION:           Survey disk                           VM#:         6906
AGENCY:                  Florida Department of Transportation
                         (FLDT)                                IDB PID#:  AA0975
SETTING CLASSIFICATION:  Concrete guardrail                    OPUS PID:        
LATITUDE:   24° 39.7' N (  24.66170)          LONGITUDE:  81° 28.1' W ( -81.46830)


The bench mark is a disk set flush in the NW concrete guardrail for the new U.S.
Highway 1 bridge, 7.22 m (23.7 ft) north of the centerline of the highway, 2.26
m (7.4 ft) west of the abutment, 1.07 m (3.5 ft) east of the west end of the
guardrail, and 1 m (3 ft) above highway level.

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

                                                                                
Station ID: 8724292                         PUBLICATION DATE:  05/28/2004
Name:       KEMP CHANNEL VIADUCT                              
            FL
NOAA Chart: 11448                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 28.1' W ( -81.46830)


                            T I D A L   D A T U M S 


Tidal datums at KEMP CHANNEL VIADUCT based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           January 1974 - February 1974
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8724211 BIG PINE KEY VIADUCT


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

     North American Vertical Datum              NAVD88 =  0.400
     MEAN HIGHER HIGH WATER                     MHHW   =  0.328
     MEAN HIGH WATER                            MHW    =  0.269
     MEAN SEA LEVEL                             MSL    =  0.168
     MEAN TIDE LEVEL                            MTL    =  0.151
     MEAN LOW WATER                             MLW    =  0.033
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 3 1937                                   3.224    2.955
     NO 1 1937                                   0.978    0.709
     NO 2 1937                                   3.793    3.524
     4292 E 1982                                 4.327    4.058
     4292 D                                      6.770    6.501


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

                                                                                
Station ID: 8724292                         PUBLICATION DATE:  05/28/2004
Name:       KEMP CHANNEL VIADUCT                              
            FL
NOAA Chart: 11448                           Latitude:   24° 39.7' N (  24.66170)
USGS Quad:  SUMMERLAND KEY                  Longitude:  81° 28.1' W ( -81.46830)


                             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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