U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                                                
Station ID: 8516501                         PUBLICATION DATE:  11/24/2014
Name:       BALDWIN, PARSONAGE COVE, HEMPSTEAD BAY            
            NY
NOAA Chart: 12352                           Latitude:   40° 38.0' N (  40.63330)
USGS Quad:  FREEPORT                        Longitude:  73° 37.0' W ( -73.61670)


To reach the station from the intersection of sunrise highway 27 and N Oceanside
road in Rockville center, proceed south on north Oceanside road 1.8 km (1.1 mi),
turn left onto Davison Avenue and then immediately continue right at the fork
onto Brower Avenue and proceed 1.3 km (0.8 mi) se to the intersection of Brower
Avenue and Moreland Avenue, turn right onto Moreland Avenue and then immediately
turn left for the mooring marina parking lot and the tide station.  The bench
marks are located along Atlantic Avenue, Church Street and Grand Boulevard.


                         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  7

                                                                                
Station ID: 8516501                         PUBLICATION DATE:  11/24/2014
Name:       BALDWIN, PARSONAGE COVE, HEMPSTEAD BAY            
            NY
NOAA Chart: 12352                           Latitude:   40° 38.0' N (  40.63330)
USGS Quad:  FREEPORT                        Longitude:  73° 37.0' W ( -73.61670)


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


                 PRIMARY BENCH MARK STAMPING:  09E06N
                         DESIGNATION:          09E 06N

MONUMENTATION:           Flange-encased Rod                    VM#:        21122
AGENCY:                  New York State Department of Public
                         Works                                 IDB PID#:  KU4802
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID:        
LATITUDE:   40° 38.5' N (  40.64125)          LONGITUDE:  73° 36.8' W ( -73.61261)


The primary bench mark is set in the grass near the NE corner of the
intersection, 11.68 m (38.3 ft) E of the center of a manhole in the sidewalk on
the E side of Grand Avenue, 6.35 m (20.8 ft) WNW of the power pole with tag
lil1, 6.20 m (20.3 ft) N of the centerline of church street and 0.23 m (0.8 ft)
N of the sidewalk.  The bench mark is set 14 cm (6 inches) below the sidewalk
being the top of a stainless steel rod encased in a NCDPW logo cap.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8516501                         PUBLICATION DATE:  11/24/2014
Name:       BALDWIN, PARSONAGE COVE, HEMPSTEAD BAY            
            NY
NOAA Chart: 12352                           Latitude:   40° 38.0' N (  40.63330)
USGS Quad:  FREEPORT                        Longitude:  73° 37.0' W ( -73.61670)


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


                         BENCH MARK STAMPING:  09E06NAZ
                         DESIGNATION:          09E 06N AZ

MONUMENTATION:           Flange-encased Rod                    VM#:        21123
AGENCY:                  New York State Department of Public
                         Works                                 IDB PID#:  KU4822
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID#: KU4822
LATITUDE:   40° 38.5' N (  40.64097)          LONGITUDE:  73° 36.6' W ( -73.60961)


The bench mark is a flange encased rod set in the sidewalk at the SW corner of
the intersection of Church Street and Grand Boulevard, 20.15 m (66.1 ft) ENE of
the school flag pole, 11.33 m (37.2 ft) W of the centerline of Grand Boulevard,
6.85 m (22.5 ft) S of the centerline of Church Street and 3.10 m (10.2 ft) ESE
of a stop sign on the S side of church street. The bench mark is set 14 cm (6
inches) below the sidewalk being the top of a stainless steel rod encased in a
NCDPW logo cap.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8516501                         PUBLICATION DATE:  11/24/2014
Name:       BALDWIN, PARSONAGE COVE, HEMPSTEAD BAY            
            NY
NOAA Chart: 12352                           Latitude:   40° 38.0' N (  40.63330)
USGS Quad:  FREEPORT                        Longitude:  73° 37.0' W ( -73.61670)


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


                         BENCH MARK STAMPING:  S 377 1956
                         DESIGNATION:          S 377

MONUMENTATION:           Bench Mark disk                       VM#:        21124
AGENCY:                  US Coast and Geodetic Survey          IDB PID#:  KU1665
SETTING CLASSIFICATION:  Brick school building                 OPUS PID:        
LATITUDE:   40° 38.4' N (  40.64047)          LONGITUDE:  73° 36.6' W ( -73.60961)


The bench mark is a disk set vertically in the SE corner of the brick school
building, 29.08 m (95.4 ft) W of the centerline of Grand Boulevard, 22.39 m
(73.5 ft) S of concrete stairs to a building entrance, 0.36 m (1.2 ft) N of the
SE corner of the building and 0.20 m (0.7 ft) above the sidewalk.



                         BENCH MARK STAMPING:  6501 A 2014
                         DESIGNATION:          851 6501 A

MONUMENTATION:           Bench Mark disk                       VM#:        21125
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Concrete base of boat house           OPUS PID:        
LATITUDE:   40° 38.3' N (  40.63786)          LONGITUDE:  73° 37.0' W ( -73.61725)


The bench mark is set on the E side of the mooring marina building on the N side
of the garage door sill, 23.98 m (78.7 ft) W of the SW corner of the cinderblock
storage building, 13.27 m (43.5 ft) S of the concrete roadway wall, 13.26 m
(43.5 ft) N of the SE corner of the mooring marina building, 5.95 m (19.5 ft) N
of the center of the man door and 0.18 m (0.6 ft) S of the N end of the door.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 8516501                         PUBLICATION DATE:  11/24/2014
Name:       BALDWIN, PARSONAGE COVE, HEMPSTEAD BAY            
            NY
NOAA Chart: 12352                           Latitude:   40° 38.0' N (  40.63330)
USGS Quad:  FREEPORT                        Longitude:  73° 37.0' W ( -73.61670)


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


                         BENCH MARK STAMPING:  6501 B 2014
                         DESIGNATION:          851 6501 B

MONUMENTATION:           Bench Mark disk                       VM#:        21126
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Concrete base of a bridge guard rail  OPUS PID:        
LATITUDE:   40° 38.3' N (  40.63819)          LONGITUDE:  73° 37.0' W ( -73.61650)


The bench mark is set in the E end of the concrete base of the guard rail along
the S side of the bridge, 10.70 m (35.1 ft) E of the W face of the E bridge
abutment, 2.68 m (8.8 ft) W of the SW corner of a rectangular electric vault
cover, 2.51 m (8.2 ft) S of the steel curb, 0.19 m (0.6 ft) E of the first guard
rail post and 0.15 m (0.5 ft) W of the W edge of the concrete wall with the
Nassau county emblem.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 8516501                         PUBLICATION DATE:  11/24/2014
Name:       BALDWIN, PARSONAGE COVE, HEMPSTEAD BAY            
            NY
NOAA Chart: 12352                           Latitude:   40° 38.0' N (  40.63330)
USGS Quad:  FREEPORT                        Longitude:  73° 37.0' W ( -73.61670)


                            T I D A L   D A T U M S 


Tidal datums at BALDWIN, PARSONAGE COVE, HEMPSTEAD BAY based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           May 2014 - July 2014
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8531680 SANDY HOOK


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

     MEAN HIGHER HIGH WATER                     MHHW   =  1.482
     MEAN HIGH WATER                            MHW    =  1.382
     MEAN SEA LEVEL                             MSL    =  0.737
     MEAN TIDE LEVEL                            MTL    =  0.719
     MEAN LOW WATER                             MLW    =  0.055
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     09E06N                                      4.275    2.893
     09E06NAZ                                    4.737    3.355
     S 377 1956                                  5.311    3.929
     6501 A 2014                                 3.565    2.183
     6501 B 2014                                 6.973    5.591


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

                                                                                
Station ID: 8516501                         PUBLICATION DATE:  11/24/2014
Name:       BALDWIN, PARSONAGE COVE, HEMPSTEAD BAY            
            NY
NOAA Chart: 12352                           Latitude:   40° 38.0' N (  40.63330)
USGS Quad:  FREEPORT                        Longitude:  73° 37.0' W ( -73.61670)


                             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.