NOAA Web Site Link Tides and Currents Home Page Transparent placeholder image

Bench Mark Sheet for 8723409, ELLIOTT KEY HARBOR, ELLIOTT KEY 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Superseded Epoch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Small blue map location marker Unpublished bench mark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  6

                                                                                
Station ID: 8723409                         PUBLICATION DATE:  01/13/2005
Name:       ELLIOTT KEY HARBOR, ELLIOTT KEY                   
            FL
NOAA Chart: 11463                           Latitude:   25° 27.2' N (  25.45330)
USGS Quad:  ELLIOTT KEY                     Longitude:  80° 11.8' W ( -80.19670)


To reach the tidal bench marks from the intersection of U.S. Highway 1 and Lucy
Street (SW 328th Street) in Florida City, proceed east on Lucy Street for 14.2
km (8.8 mi) to the boat ramp at Biscayne National Park.  Then via boat, continue
east for 14.0 km (8.7 statute mi) to the Elliott Key Visitor Center Boat Basin
on the west side of Elliott Key.  The bench marks are in the vicinity of the
boat basin visitor center, and maintenance dock.  The tide gage and staff were
on the maintenance dock south of the basin.


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


                 PRIMARY BENCH MARK STAMPING:  NO 3 1974
                         DESIGNATION:          872 3409 TIDAL 3

MONUMENTATION:           Tidal Station disk                    VM#:         5837
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   25° 27.2' N (  25.45330)          LONGITUDE:  80° 11.8' W ( -80.19670)


The primary bench mark is a disk set in a rock outcrop east of the boat basin,
41.21 m (135.2 ft) SSE of a light pole at the east end of the center of three
piers, 30 m (100 ft) east of the center pier, 17.13 m (56.2 ft) east of the
easternmost corner of the boat basin south of the center pier, 7.77 m (25.5 ft)
ENE of bench mark 19, and 1 m (4 ft) north of a tree.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                                                
Station ID: 8723409                         PUBLICATION DATE:  01/13/2005
Name:       ELLIOTT KEY HARBOR, ELLIOTT KEY                   
            FL
NOAA Chart: 11463                           Latitude:   25° 27.2' N (  25.45330)
USGS Quad:  ELLIOTT KEY                     Longitude:  80° 11.8' W ( -80.19670)


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


                         BENCH MARK STAMPING:  3409 F 1987
                         DESIGNATION:          872 3409 F

MONUMENTATION:           Tidal Station disk                    VM#:         5838
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete foundation for flagpole      OPUS PID:        
LATITUDE:   25° 27.2' N (  25.45330)          LONGITUDE:  80° 11.8' W ( -80.19670)


The bench mark is a disk set flush in the east side of a concrete foundation for
a flagpole at the western end of the center piers at the boat basin.



                         BENCH MARK STAMPING:  3409 G 1987
                         DESIGNATION:          872 3409 G

MONUMENTATION:           Tidal Station disk                    VM#:         5839
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete footing of dock              OPUS PID:        
LATITUDE:   25° 27.2' N (  25.45330)          LONGITUDE:  80° 11.8' W ( -80.19670)


The bench mark is a disk set in the concrete footing at the east end of the
maintenance dock, 4.27 m (14.0 ft) west of the NE corner of the dock, 0.15 m
(0.5 ft) south of the north edge of the dock, and level with the dock.

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

                                                                                
Station ID: 8723409                         PUBLICATION DATE:  01/13/2005
Name:       ELLIOTT KEY HARBOR, ELLIOTT KEY                   
            FL
NOAA Chart: 11463                           Latitude:   25° 27.2' N (  25.45330)
USGS Quad:  ELLIOTT KEY                     Longitude:  80° 11.8' W ( -80.19670)


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


                         BENCH MARK STAMPING:  3409 H 1987
                         DESIGNATION:          872 3409 H

MONUMENTATION:           Tidal Station disk                    VM#:         5840
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   25° 27.2' N (  25.45330)          LONGITUDE:  80° 11.8' W ( -80.19670)


The bench mark is a disk set in the WSW corner of a deck located between the
Visitor Center and the public restroom, 8.69 m (28.5 ft) ENE of the east corner
of the restroom building, 3.57 m (11.7 ft) SSW of the south corner of the
Visitor Center, and 0.61 m (2.0 ft) WSW of the deck corner.  The bench mark is
set level with the ground, crimped to the top of a stainless steel rod driven
0.6 m (2 ft) to refusal, and encased in a PVC pipe with concrete kickblock.



                         BENCH MARK STAMPING:  3409 J 1987
                         DESIGNATION:          872 3409 J

MONUMENTATION:           Tidal Station disk                    VM#:         5841
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete step                         OPUS PID:        
LATITUDE:   25° 27.2' N (  25.45330)          LONGITUDE:  80° 11.8' W ( -80.19670)


The bench mark is a disk set in the first step at the SW corner of the generator
building, about 96 m (315 ft) ESE of the maintenance dock, 0.49 m (1.6 ft) SE of
the NW corner of the building, and 0.21 m (0.7 ft) SSW of the west side of the
building.

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

                                                                                
Station ID: 8723409                         PUBLICATION DATE:  01/13/2005
Name:       ELLIOTT KEY HARBOR, ELLIOTT KEY                   
            FL
NOAA Chart: 11463                           Latitude:   25° 27.2' N (  25.45330)
USGS Quad:  ELLIOTT KEY                     Longitude:  80° 11.8' W ( -80.19670)


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


                         BENCH MARK STAMPING:  19
                         DESIGNATION:          872 3409 19 TIDAL

MONUMENTATION:           Survey disk                           VM#:         5842
AGENCY:                  National Park Service (NPS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   25° 27.2' N (  25.45330)          LONGITUDE:  80° 11.8' W ( -80.19670)


The bench mark is a disk set in a rock outcrop east of the boat basin, 39.17 m
(128.5 ft) SSE of a light pole at the boast basin, 31.94 m (104.8 ft) north of
the northernmost corner of a picnic shelter, 9.57 m (31.4 ft) east of the
easternmost corner of the south basin, 7.77 m (25.5 ft) WSW of bench mark NO 3
1974, and level with the ground.

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

                                                                                
Station ID: 8723409                         PUBLICATION DATE:  01/13/2005
Name:       ELLIOTT KEY HARBOR, ELLIOTT KEY                   
            FL
NOAA Chart: 11463                           Latitude:   25° 27.2' N (  25.45330)
USGS Quad:  ELLIOTT KEY                     Longitude:  80° 11.8' W ( -80.19670)


                            T I D A L   D A T U M S 


Tidal datums at ELLIOTT KEY HARBOR, ELLIOTT KEY based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           July 1974 - July 1974
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8723350 RAGGED KEY #3


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.506
     MEAN HIGH WATER                            MHW    =  0.481
     MEAN TIDE LEVEL                            MTL    =  0.256
     MEAN SEA LEVEL                             MSL    =  0.247
     MEAN LOW WATER                             MLW    =  0.031
     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 1974                                   1.688    1.207
     3409 F 1987                                 1.246    0.765
     3409 G 1987                                 1.183    0.702
     3409 H 1987                                 2.225    1.744
     3409 J 1987                                 2.924    2.443
     19                                          1.496    1.015


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

                                                                                
Station ID: 8723409                         PUBLICATION DATE:  01/13/2005
Name:       ELLIOTT KEY HARBOR, ELLIOTT KEY                   
            FL
NOAA Chart: 11463                           Latitude:   25° 27.2' N (  25.45330)
USGS Quad:  ELLIOTT KEY                     Longitude:  80° 11.8' W ( -80.19670)


                             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.

Return to Top
Products available at 8723409 ELLIOTT KEY HARBOR, ELLIOTT KEY, FL

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services