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

                                                                                
Station ID: 9759938                         PUBLICATION DATE:  10/21/2020
Name:       MONA ISLAND                                       
            PR
NOAA Chart: 25671                           Latitude:   18°  5.4' N (  18.08992)
USGS Quad:  ISLA MONA                       Longitude:  67° 56.3' W ( -67.93850)


To reach the bench marks on Mona Island, travel west offshore from Rincon,
Puerto Rico, 40 miles (34.8 nm). The bench marks are on the DNRAs pier and the
road leading to the pier.  DNRA is located on the southwest side of Mona Island
and is the only facility on the island.  The station is located on the pier and
is attached to an abandoned building on the pier.  


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


                 PRIMARY BENCH MARK STAMPING:  9938 A 2006
                         DESIGNATION:          975 9938 A

MONUMENTATION:           Tidal Station disk                    VM#:        18192
AGENCY:                  National Ocean Service                IDB PID#:  DN8596
SETTING CLASSIFICATION:  Concrete pier                         OPUS PID#: DN8596
LATITUDE:   18°  5.4' N (  18.08992)          LONGITUDE:  67° 56.3' W ( -67.93850)


The primary bench mark is a disk located on a concrete pier of the DNR near the
tide station. 17.30 m (56.8 ft) WSW of the SW corner of an abandoned building on
the pier, 6.20 m (20.3 ft) SW of the NW corner of the pier, and 0.50 m (1.6 ft)
SE of the NW face of the pier.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 9759938                         PUBLICATION DATE:  10/21/2020
Name:       MONA ISLAND                                       
            PR
NOAA Chart: 25671                           Latitude:   18°  5.4' N (  18.08992)
USGS Quad:  ISLA MONA                       Longitude:  67° 56.3' W ( -67.93850)


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


                         BENCH MARK STAMPING:  9938 C 2006
                         DESIGNATION:          975 9938 C

MONUMENTATION:           Tidal Station disk                    VM#:        18191
AGENCY:                  National Ocean Service                IDB PID#:  DN8598
SETTING CLASSIFICATION:  Concrete road                         OPUS PID:        
LATITUDE:   18°  5.3' N (  18.08908)          LONGITUDE:  67° 56.3' W ( -67.93806)


The bench mark is set in the road leading to the DNR pier, 22.35 m (73.3 ft) NE
of the end of the concrete road leading to the pier, 18.10 m (59.4 ft) SSW of
the first range marker off the pier, 1.30 m (4.27 ft) NW of the center of the
road, 0.20 m (0.7 ft) SE of the NW edge of the road, and flush with the road.



                         BENCH MARK STAMPING:  9938 B 2006
                         DESIGNATION:          975 9938 B

MONUMENTATION:           Tidal Station disk                    VM#:        18193
AGENCY:                  National Ocean Service                IDB PID#:  DN8597
SETTING CLASSIFICATION:  Concrete road                         OPUS PID:        
LATITUDE:   18°  5.4' N (  18.08922)          LONGITUDE:  67° 56.3' W ( -67.93819)


The bench mark is set in the road at the DNR pier, 24.80 m (81.4 ft) SE of the
NE face of the concrete pier, 17.50 m (57.4 ft) north of the first range marker
off the pier, 5.35 m (17.6 ft) NE of the SW face of the pier, 0.50 m (1.64 ft)
SW of the SE corner of the building on the pier.

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

                                                                                
Station ID: 9759938                         PUBLICATION DATE:  10/21/2020
Name:       MONA ISLAND                                       
            PR
NOAA Chart: 25671                           Latitude:   18°  5.4' N (  18.08992)
USGS Quad:  ISLA MONA                       Longitude:  67° 56.3' W ( -67.93850)


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


                         BENCH MARK STAMPING:  9938 D 2006
                         DESIGNATION:          975 9938 D

MONUMENTATION:           Tidal Station disk                    VM#:        18194
AGENCY:                  National Ocean Service                IDB PID#:  DN8599
SETTING CLASSIFICATION:  Concrete pad                          OPUS PID:        
LATITUDE:   18°  5.3' N (  18.08856)          LONGITUDE:  67° 56.3' W ( -67.93792)


The bench mark is set in a 0.55 m (1.80 ft) X 0.65 m (2.13 ft) concrete pad on
the DNR property near the camp ground east of the pier, 5.00 m (16.40 ft) west
of the eastern most concrete foundation, and 0.30 m (0.98 ft) above ground.



                         BENCH MARK STAMPING:  9938 E 2006
                         DESIGNATION:          975 9938 E

MONUMENTATION:           Tidal Station disk                    VM#:        18195
AGENCY:                  National Ocean Service                IDB PID#:  DN8600
SETTING CLASSIFICATION:  Concrete Pad                          OPUS PID:        
LATITUDE:   18°  5.3' N (  18.08817)          LONGITUDE:  67° 56.3' W ( -67.93836)


The bench mark is set in the concrete foundation supporting the steps leading to
the camp ground restrooms on the DNR property, 24.00 m (78.7 ft) NE of the SE
corner of a ranger office, 10.80 m (35.4 ft) ESE of a DNRA sign, 3.40 m (11.2
ft) SW of the NW corner of the camp restrooms, and 0.50 m (1.6 ft) above ground.

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

                                                                                
Station ID: 9759938                         PUBLICATION DATE:  10/21/2020
Name:       MONA ISLAND                                       
            PR
NOAA Chart: 25671                           Latitude:   18°  5.4' N (  18.08992)
USGS Quad:  ISLA MONA                       Longitude:  67° 56.3' W ( -67.93850)


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


                         BENCH MARK STAMPING:  9938 F 2007
                         DESIGNATION:          975 9938 F

MONUMENTATION:           Tidal Station disk                    VM#:        18257
AGENCY:                  National Ocean Service                IDB PID#:  DN8601
SETTING CLASSIFICATION:  Concrete pad                          OPUS PID#: DN8601
LATITUDE:   18°  5.3' N (  18.08764)          LONGITUDE:  67° 56.4' W ( -67.93925)


The bench mark is set in a concrete foundation for an automotive lift ramp
supporting station, located on the NW side of the basketball courts, 17.04 m
(55.9 ft) SE of the SE corner of the living quarters located NW of the
basketball court, 15.90 m (52.17 ft) north of the SW corner of the basketball
court, 11.22 m (36.81 ft) west of the NE corner of the basketball court, 0.20 m
(0.6 ft) above the ground, set in an old concrete car lift ramp pad 5.0 m (16.4
ft) x 2.6 m (8.5ft).



                         BENCH MARK STAMPING:  9938 G 2008
                         DESIGNATION:          975 9938 G

MONUMENTATION:           Tidal Station disk                    VM#:        18686
AGENCY:                                                        IDB PID#:  DN8602
SETTING CLASSIFICATION:  Concrete pad                          OPUS PID:        
LATITUDE:   18°  5.2' N (  18.08747)          LONGITUDE:  67° 56.3' W ( -67.93881)


The benchmark is a disk set in a concrete foundation at the base of a stair case
hand rail in the northern most of two residential buildings and closest to the
mess hall on the SW side of Mona Island near the basketball court, 31.7 m (104.0
ft) SE of the SE corner of the basketball court, 5.4 m (17.8 ft) SW of the NE
corner of a residential building next to the mess hall building, 0.38 m (1.2 ft)
south of the NE corner of a concrete foundation at the base of the staircase,
11.58 cm (5 in) above ground.

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

                                                                                
Station ID: 9759938                         PUBLICATION DATE:  10/21/2020
Name:       MONA ISLAND                                       
            PR
NOAA Chart: 25671                           Latitude:   18°  5.4' N (  18.08992)
USGS Quad:  ISLA MONA                       Longitude:  67° 56.3' W ( -67.93850)


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


                         BENCH MARK STAMPING:  9938 H 2014
                         DESIGNATION:          975 9938 H

MONUMENTATION:           Tidal Station disk                    VM#:        21136
AGENCY:                  National Ocean Service                IDB PID:         
SETTING CLASSIFICATION:  Concrete Step                         OPUS PID:        
LATITUDE:   18°  5.2' N (  18.08747)          LONGITUDE:  67° 56.4' W ( -67.94003)


The bench mark is a disk set flush in the steps of the Mona Island research and
education building on the SW side of the island, 13.8 m (45.3 ft) south of the
SE corner of the building, 7.30 m (24.0 ft) NE of a set of double doors at the
entrance to the building, 1.80 m (5.9 ft) north of the NE corner of the
building, and set flush in the second step on the NE side of the steps.

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

                                                                                
Station ID: 9759938                         PUBLICATION DATE:  10/21/2020
Name:       MONA ISLAND                                       
            PR
NOAA Chart: 25671                           Latitude:   18°  5.4' N (  18.08992)
USGS Quad:  ISLA MONA                       Longitude:  67° 56.3' W ( -67.93850)


                            T I D A L   D A T U M S 


Tidal datums at MONA ISLAND based on:

     LENGTH OF SERIES:      8 YEARS
     TIME PERIOD:           03/10-02/17, 04/18-03/19
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9759110 MAGUEYES ISLAND, CARIBBEAN SEA


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

     HIGHEST OBSERVED WATER LEVEL (09/21/2017)         =  0.880
     MEAN HIGHER HIGH WATER                     MHHW   =  0.247
     MEAN HIGH WATER                            MHW    =  0.231
     MEAN TIDE LEVEL                            MTL    =  0.126
     MEAN SEA LEVEL                             MSL    =  0.125
     Puerto Rico Vertical Datum of 2002         PRVD02 =  0.124
     MEAN LOW WATER                             MLW    =  0.021
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (04/27/2009)         = -0.220



Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     9938 A 2006                                 1.282    1.051
     9938 C 2006                                 2.395    2.164
     9938 B 2006                                 1.365    1.134
     9938 D 2006                                 3.338    3.107
     9938 E 2006                                 2.968    2.737
     9938 F 2007                                 3.084    2.853
     9938 G 2008                                 2.594    2.363
     9938 H 2014                                 2.377    2.146


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

                                                                                
Station ID: 9759938                         PUBLICATION DATE:  10/21/2020
Name:       MONA ISLAND                                       
            PR
NOAA Chart: 25671                           Latitude:   18°  5.4' N (  18.08992)
USGS Quad:  ISLA MONA                       Longitude:  67° 56.3' W ( -67.93850)


                             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 any other fixed island datum.

This tide station location has a defined island datum (PRVD02).  Island datums
are specific fixed geodetic datums whose elevation relationship 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 PRVD02 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have PRVD02 elevations.
The PRVD02 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, PRVD02 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from PRVD02 elevations listed for
each bench mark in the NGS database.