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

                                                                                
Station ID: 8515186                         PUBLICATION DATE:  12/16/2004
Name:       FIRE ISLAND COAST GUARD STATION                   
            NY
NOAA Chart: 12353                           Latitude:   40° 37.6' N (  40.62670)
USGS Quad:  BAY SHORE WEST                  Longitude:  73° 15.6' W ( -73.26000)


To reach the tidal bench marks from the south point of the traffic circle at the
south end of the Robert Moses Causeway on Fire Island, proceed east on the park
road for 0.8 km (0.5 mi) to a turnaround and then head back west for 0.3 km (0.2
mi) to the entrance to Fire Island Coast Guard Station, then follow the entrance
road west to the station boat basin on Fire island Inlet.  The bench marks are
located near the station and east along the park road.  The tide gage and staff
were on the outside of the west bulkhead of the boat basin.


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


                 PRIMARY BENCH MARK STAMPING:  5186 A 1989
                         DESIGNATION:          851 5186 A

MONUMENTATION:           Tidal Station disk                    VM#:         2307
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete foundation of a tower        OPUS PID:        
LATITUDE:   40° 37.6' N (  40.62670)          LONGITUDE:  73° 15.6' W ( -73.26000)


The primary bench mark is a disk set flush in the NW corner of the square
concrete base of the antenna tower, 31 m (102 ft) south of the SW corner of the
boat basin dock, 29.02 m (95.2 ft) north of the NW corner of the maintenance
building, 4.36 m (14.3 ft) west of a chain link fence, and 0.15 m (0.5 ft) below
the top surface of the round steel base of the antenna.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  8

                                                                                
Station ID: 8515186                         PUBLICATION DATE:  12/16/2004
Name:       FIRE ISLAND COAST GUARD STATION                   
            NY
NOAA Chart: 12353                           Latitude:   40° 37.6' N (  40.62670)
USGS Quad:  BAY SHORE WEST                  Longitude:  73° 15.6' W ( -73.26000)


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


                         BENCH MARK STAMPING:  NO 7 1933
                         DESIGNATION:          TIDAL 7 STA II 68

MONUMENTATION:           Tidal Station disk                    VM#:         2303
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  KU0723
SETTING CLASSIFICATION:  Granite foundation block              OPUS PID:        
LATITUDE:   40° 37.9' N (  40.63170)          LONGITUDE:  73° 13.1' W ( -73.21830)


The bench mark is a disk set in a granite foundation block on the north side of
the Fire Island Lighthouse tower, in the circular rim of the lighthouse, 3.5 km
(2.2 mi) east of Fire Island Coast Guard Station, and 0.46 m (1.5 ft) above the
brick terrace built around the lighthouse.

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

                                                                                
Station ID: 8515186                         PUBLICATION DATE:  12/16/2004
Name:       FIRE ISLAND COAST GUARD STATION                   
            NY
NOAA Chart: 12353                           Latitude:   40° 37.6' N (  40.62670)
USGS Quad:  BAY SHORE WEST                  Longitude:  73° 15.6' W ( -73.26000)


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


                         BENCH MARK STAMPING:  R 375 1956
                         DESIGNATION:          R 375

MONUMENTATION:           Tidal Station disk                    VM#:         2304
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  KU0724
SETTING CLASSIFICATION:  Concrete base                         OPUS PID:        
LATITUDE:   40° 37.9' N (  40.63170)          LONGITUDE:  73° 12.9' W ( -73.21500)


The bench mark is a disk set in the top of a 1 m x 1 m (3 ft x 3 ft) concrete
base of a former tower, in the most southern one of three bases, at the Fire
Island Coast Guard Radio Station, 2.1 km (1.3 mi) west along Dune road from the
water tank at Saltaire, 21.88 m (71.8 ft) SE of the SW corner of the radio
station building, and 18.11 m (59.4 ft) south of the south side of the building.

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

                                                                                
Station ID: 8515186                         PUBLICATION DATE:  12/16/2004
Name:       FIRE ISLAND COAST GUARD STATION                   
            NY
NOAA Chart: 12353                           Latitude:   40° 37.6' N (  40.62670)
USGS Quad:  BAY SHORE WEST                  Longitude:  73° 15.6' W ( -73.26000)


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


                         BENCH MARK STAMPING:  S 375 1956
                         DESIGNATION:          S 375

MONUMENTATION:           Bench Mark disk                       VM#:         2305
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  KU0725
SETTING CLASSIFICATION:  Concrete base                         OPUS PID:        
LATITUDE:   40° 37.9' N (  40.63170)          LONGITUDE:  73° 12.9' W ( -73.21500)


The bench mark is a disk set in the top of a 1.22 m x 1.71 m (4.0 ft x 5.6 ft)
concrete base of a former radio tower at the Fire Island Coast Guard Radio
Station, 52 m (172 ft) east of the NE corner of the radio station building, and
52 m (170 ft) east of the radio tower.



                         BENCH MARK STAMPING:  V 375 RESET 1968
                         DESIGNATION:          851 5186 V 375 RESET

MONUMENTATION:           Tidal Station disk                    VM#:         2306
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete helicopter pad               OPUS PID#: BBDC06
LATITUDE:   40° 37.5' N (  40.62542)          LONGITUDE:  73° 15.5' W ( -73.25889)


The bench mark is a disk set flush near the center of the concrete helicopter
pad, 39.99 m (131.2 ft) SE of the SE corner of the wood-sided boat house, 19.57
m (64.2 ft) north of the south corner of the pad, and 19.08 m (62.6 ft) west of
the east corner of the pad.

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

                                                                                
Station ID: 8515186                         PUBLICATION DATE:  12/16/2004
Name:       FIRE ISLAND COAST GUARD STATION                   
            NY
NOAA Chart: 12353                           Latitude:   40° 37.6' N (  40.62670)
USGS Quad:  BAY SHORE WEST                  Longitude:  73° 15.6' W ( -73.26000)


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


                         BENCH MARK STAMPING:  5186 B 1989
                         DESIGNATION:          851 5186 B

MONUMENTATION:           Tidal Station disk                    VM#:         2308
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete bridge abutment              OPUS PID#: BBDG76
LATITUDE:   40° 37.5' N (  40.62494)          LONGITUDE:  73° 15.7' W ( -73.26181)


The bench mark is a disk set flush in the SE concrete bridge abutment of the
Robert Moses Causeway over Fire Island Inlet, 4.88 m (16.0 ft) SE of the
centerline of the highway, 4.82 m (15.8 ft) north of the SE inside corner of the
wingwall, and 0.26 m (0.85 ft) SW of the NE edge of the abutment.



                         BENCH MARK STAMPING:  5 579
                         DESIGNATION:          851 5186 5 579

MONUMENTATION:           Survey disk                           VM#:         2309
AGENCY:                  Suffolk County                        IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   40° 37.6' N (  40.62639)          LONGITUDE:  73° 15.9' W ( -73.26486)


The bench mark is a disk set in a concrete monument near the entrance lane to
Field 4, 0.4 km (0.25 mi) east of bench mark 5 580, 12.74 m (41.8 ft) SW of a
painted cross in the pavement with a chiseled X in the center, 7.25 m (23.8 ft)
SE of a railroad spike with chiseled X set in the seam of the concrete pavement
along the edge of the road, and 4.36 m (14.3 ft) south of the edge of the
pavement.

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

                                                                                
Station ID: 8515186                         PUBLICATION DATE:  12/16/2004
Name:       FIRE ISLAND COAST GUARD STATION                   
            NY
NOAA Chart: 12353                           Latitude:   40° 37.6' N (  40.62670)
USGS Quad:  BAY SHORE WEST                  Longitude:  73° 15.6' W ( -73.26000)


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


                         BENCH MARK STAMPING:  5 580
                         DESIGNATION:          851 5186 5 580

MONUMENTATION:           Survey disk                           VM#:         2310
AGENCY:                  Suffolk County                        IDB PID#:        
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   40° 37.5' N (  40.62528)          LONGITUDE:  73° 15.2' W ( -73.25300)


The bench mark is a disk set in a concrete monument near the first turnaround
east of the traffic circle at the south end of the Robert Moses Causeway, 16.37
m (53.7 ft) SE of a railroad spike with chiseled cross set near the edge of the
road, 15.82 m (51.9 ft) SW of a second spike in the road near a sign for the
Coast Guard Station - Fields 2&3, 7.99 m (26.2 ft) SSE of a third spike along
the centerline of the road, and 3.96 m (13 ft) south of the edge of the
pavement.

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

                                                                                
Station ID: 8515186                         PUBLICATION DATE:  12/16/2004
Name:       FIRE ISLAND COAST GUARD STATION                   
            NY
NOAA Chart: 12353                           Latitude:   40° 37.6' N (  40.62670)
USGS Quad:  BAY SHORE WEST                  Longitude:  73° 15.6' W ( -73.26000)


                            T I D A L   D A T U M S 


Tidal datums at FIRE ISLAND COAST GUARD STATION based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           December 1989 - November 1990
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8518750 THE BATTERY, NEW YORK HARBOR


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

     HIGHEST OBSERVED WATER LEVEL (10/19/1989)         =  1.133
     MEAN HIGHER HIGH WATER                     MHHW   =  0.705
     MEAN HIGH WATER                            MHW    =  0.649
     North American Vertical Datum              NAVD88 =  0.404
     MEAN SEA LEVEL                             MSL    =  0.344
     MEAN TIDE LEVEL                            MTL    =  0.344
     MEAN LOW WATER                             MLW    =  0.040
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (11/12/1990)         = -0.613

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     5186 A 1989                                 2.976    2.327
     NO 7 1933                                   5.100    4.451
     R 375 1956                                  3.112    2.463
     S 375 1956                                  2.660    2.011
     V 375 RESET 1968                            3.163    2.514
     5186 B 1989                                 7.958    7.309
     5 579                                       4.793    4.144
     5 580                                       4.802    4.153


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

                                                                                
Station ID: 8515186                         PUBLICATION DATE:  12/16/2004
Name:       FIRE ISLAND COAST GUARD STATION                   
            NY
NOAA Chart: 12353                           Latitude:   40° 37.6' N (  40.62670)
USGS Quad:  BAY SHORE WEST                  Longitude:  73° 15.6' W ( -73.26000)


                             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.