U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                                                
Station ID: 8516614                         PUBLICATION DATE:  09/05/2003
Name:       GLEN COVE YACHT CLUB, LONG ISLAND                 
            NY
NOAA Chart: 12366                           Latitude:   40° 51.8' N (  40.86330)
USGS Quad:  SEA CLIFF                       Longitude:  73° 39.3' W ( -73.65500)


To reach the tidal bench marks from the Glen Cove firehouse at the intersection
of Glen Cove Road and Glen Cove Avenue, proceed south on Glen Cove Avenue, take
the first right onto Charles Street, then left on The Place (bends to right and
becomes Elwood Street), then left on McLoughlin to the end of the street at Glen
Cove Yacht Club.  The bench marks are in the retaining wall of the dock.  The
tide gauge and staff were at the west end of the dock.


                         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  6

                                                                                
Station ID: 8516614                         PUBLICATION DATE:  09/05/2003
Name:       GLEN COVE YACHT CLUB, LONG ISLAND                 
            NY
NOAA Chart: 12366                           Latitude:   40° 51.8' N (  40.86330)
USGS Quad:  SEA CLIFF                       Longitude:  73° 39.3' W ( -73.65500)


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


                 PRIMARY BENCH MARK STAMPING:  BM NO 3 1934
                         DESIGNATION:          TIDAL 3 STA II 10

MONUMENTATION:           Tidal Station disk                    VM#:         7088
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  KU1595
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   40° 51.8' N (  40.86330)          LONGITUDE:  73° 39.2' W ( -73.65330)


The primary bench mark is a disk set in the top of the north concrete retaining
wall at the junction of a low wire fence and a high wire fence, and 46 m (151
ft) east of bench mark NO 2 1934.

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

                                                                                
Station ID: 8516614                         PUBLICATION DATE:  09/05/2003
Name:       GLEN COVE YACHT CLUB, LONG ISLAND                 
            NY
NOAA Chart: 12366                           Latitude:   40° 51.8' N (  40.86330)
USGS Quad:  SEA CLIFF                       Longitude:  73° 39.3' W ( -73.65500)


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


                         BENCH MARK STAMPING:  BM NO 1 1934
                         DESIGNATION:          TIDAL 1 STA II 10

MONUMENTATION:           Tidal Station disk                    VM#:         7086
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  KU1594
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   40° 51.8' N (  40.86330)          LONGITUDE:  73° 39.2' W ( -73.65330)


The bench mark is a disk set in the top of the west end of the south concrete
retaining wall at the SW corner of the dock, and 4 m (13 ft) south of a concrete
ramp leading to a boat landing.

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

                                                                                
Station ID: 8516614                         PUBLICATION DATE:  09/05/2003
Name:       GLEN COVE YACHT CLUB, LONG ISLAND                 
            NY
NOAA Chart: 12366                           Latitude:   40° 51.8' N (  40.86330)
USGS Quad:  SEA CLIFF                       Longitude:  73° 39.3' W ( -73.65500)


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


                         BENCH MARK STAMPING:  BM NO 2 1934
                         DESIGNATION:          TIDAL 2 STA II 10

MONUMENTATION:           Tidal Station disk                    VM#:         7087
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  KU1593
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID#: KU1593
LATITUDE:   40° 51.8' N (  40.86330)          LONGITUDE:  73° 39.2' W ( -73.65330)


The bench mark is a disk set in the top of the north concrete retaining wall, 31
m (102 ft) north of bench mark NO 1 1934, and 12 m (39 ft) east of the west end
of the retaining wall.

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

                                                                                
Station ID: 8516614                         PUBLICATION DATE:  09/05/2003
Name:       GLEN COVE YACHT CLUB, LONG ISLAND                 
            NY
NOAA Chart: 12366                           Latitude:   40° 51.8' N (  40.86330)
USGS Quad:  SEA CLIFF                       Longitude:  73° 39.3' W ( -73.65500)


                            T I D A L   D A T U M S 


Tidal datums at GLEN COVE YACHT CLUB, LONG ISLAND based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           June 1990 - August 1990
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8518490 NEW ROCHELLE


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.398
     MEAN HIGH WATER                            MHW    =  2.287
     North American Vertical Datum              NAVD88 =  1.265
     MEAN SEA LEVEL                             MSL    =  1.181
     MEAN TIDE LEVEL                            MTL    =  1.179
     MEAN LOW WATER                             MLW    =  0.071
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     BM NO 3 1934                                4.653    2.366
     BM NO 1 1934                                4.533    2.246
     BM NO 2 1934                                4.498    2.211


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

                                                                                
Station ID: 8516614                         PUBLICATION DATE:  09/05/2003
Name:       GLEN COVE YACHT CLUB, LONG ISLAND                 
            NY
NOAA Chart: 12366                           Latitude:   40° 51.8' N (  40.86330)
USGS Quad:  SEA CLIFF                       Longitude:  73° 39.3' W ( -73.65500)


                             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.