Superseded Bench Mark Sheet for 8451351, SACHUEST, FLINT POINT RI

Present Epoch

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  4

                                                   PUBLICATION DATE:  08/30/1985
Station ID: 8451351                                SUPERCEDED DATE:   04/21/2003
Name:       SACHUEST, FLINT POINT, SAKONNET RIVER             
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 29.2' N
USGS Quad:  SAKONNET POINT                         Longitude:        71° 14.3' W


To reach the tidal bench marks from Newport, Rhode Island, take State Route 138A
east which turns into Memorial Boulevard, then Purgatory Road to Sachuest, a
wildlife refuge.  Take the first left (road blocked by a cable) to a dirt road
that will lead to the Flint Point which is located at the NE corner of Sachuest
Point.  The bench marks are located in the rocks along the shoreline at Flint
Point.  The tide gage was mounted onshore with the orifice and tubing extending
offshore.  The tide staff was mounted on the rocks east of the tide gage.


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


                 PRIMARY BENCH MARK STAMPING:  1351 A 1977

MONUMENTATION:           Survey Disk                               VM#:     2143
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Rock Outcrop


The bench mark is set flush in concrete on a rock outcrop at Flint Point in
Sachuest Wildlife Refuge, 100 feet (30 m) west of the east shoreline, 24 feet (7
m) south of the north shoreline, 14 feet (4 m) north from the bottom of the
incline that leads to the dirt road.



                         BENCH MARK STAMPING:  1351 B 1977

MONUMENTATION:           Survey Disk                               VM#:     2144
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Rock Outcrop


The bench mark is set flush in concrete on a rock outcrop at Flint Point in
Sachuest Wildlife Refuge, 200 feet (61 m) north of Bench Mark 1351 C 1977, 100
feet (30 m) south of the north shoreline, 33 feet (10 m) NE of the bottom of the
incline that leads to the dirt road, and 17 feet (5 m) west of the east
shoreline.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  4

                                                   PUBLICATION DATE:  08/30/1985
Station ID: 8451351                                SUPERCEDED DATE:   04/21/2003
Name:       SACHUEST, FLINT POINT, SAKONNET RIVER             
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 29.2' N
USGS Quad:  SAKONNET POINT                         Longitude:        71° 14.3' W


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


                         BENCH MARK STAMPING:  1351 C 1977

MONUMENTATION:           Survey Disk                               VM#:     2145
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Rock Outcrop


The bench mark is set flush in concrete on a rock outcrop at Flint Point in
Sachuest Wildlife Refuge, 200 feet (61 m) south of Bench Mark 1351 B 1977, 100
feet (30 m) north of Bench Mark 1351 E 1977, 60 feet (18 m) south of Bench Mark
1351 D 1977, 52 feet (16 m) east of the centerline of the dirt road, and 50 feet
(15 m) west of the east shoreline.



                         BENCH MARK STAMPING:  1351 D 1977

MONUMENTATION:           Survey Disk                               VM#:     2146
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Rock Outcrop


The bench mark is set flush on concrete in a rock outcrop at Flint Point in
Sachuest Wildlife Refuge, 150 feet (46 m) west of the east shoreline, 60 feet
(18 m) north of Bench Mark 1351 C 1977, and 15 feet (5 m) east from the bottom
of the incline leading to the dirt road.



                         BENCH MARK STAMPING:  1351 E 1977

MONUMENTATION:           Survey Disk                               VM#:     2147
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Rock Outcrop


The bench mark is set flush in concrete on a rock outcrop at Flint Point at
Sachuest Wildlife Refuge, 150 feet (46 m) north of a large outcrop of white
marble like rocks, 100 feet (30 m) south of Bench Mark 1351 C 1977, 50 feet (15
m) west of the east shoreline, and 46 feet (14 m) SE of the centerline of the
dirt road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  4

                                                   PUBLICATION DATE:  08/30/1985
Station ID: 8451351                                SUPERCEDED DATE:   04/21/2003
Name:       SACHUEST, FLINT POINT, SAKONNET RIVER             
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 29.2' N
USGS Quad:  SAKONNET POINT                         Longitude:        71° 14.3' W


                            T I D A L   D A T U M S 


Tidal datums at SACHUEST, FLINT POINT, SAKONNET RIVER based on:

     LENGTH OF SERIES:      2 MONTHS
     TIME PERIOD:           AUGUST-SEPTEMBER 1977
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8452660 NEWPORT


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

     HIGHEST OBSERVED WATER LEVEL (10/15/1977)         =   5.46
     MEAN HIGHER HIGH WATER                     MHHW   =   3.55
     MEAN HIGH WATER                            MHW    =   3.31
     MEAN TIDE LEVEL                            MTL    =   1.72
     MEAN LOW WATER                             MLW    =   0.13
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (10/17/1977)         =  -1.24



Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     1351 A 1977                                 7.61      4.30
     1351 B 1977                                 7.16      3.85
     1351 C 1977                                13.10      9.79
     1351 D 1977                                 8.99      5.68
     1351 E 1977                                12.71      9.40


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

                                                   PUBLICATION DATE:  08/30/1985
Station ID: 8451351                                SUPERCEDED DATE:   04/21/2003
Name:       SACHUEST, FLINT POINT, SAKONNET RIVER             
            RHODE ISLAND
NOAA Chart: 13221                                  Latitude:         41° 29.2' N
USGS Quad:  SAKONNET POINT                         Longitude:        71° 14.3' W


                             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 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.

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Products available at 8451351 SACHUEST, FLINT POINT, RI