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

                                                                                
Station ID: 9464075                         PUBLICATION DATE:  01/04/2018
Name:       MESHIK, PORT HEIDEN                               
            AK
NOAA Chart: 16343                           Latitude:   56° 54.5' N (  56.90825)
USGS Quad:  CHIGNIK D-3                     Longitude: 158° 41.1' W (-158.68492)


To reach the tidal bench marks from the Port Heiden Airport, proceed SE on Lower
Site Road for 0.7 km (0.4 mi) to the intersection with Airport Road, turn right
and continue SW on Airport Road  for 6.2 km (3.9 mi) to its termination at the
ocean at the far south end of old Meshik Village.  The bench marks are in the
vicinity of old Meshik Village on the southern end of town. The tide gauge was
located at the end of Airport Road.


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


                 PRIMARY BENCH MARK STAMPING:  4075 B 2013
                         DESIGNATION:          946 4075 B

MONUMENTATION:           Flange-encased Rod                    VM#:        22541
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID#: BBDG96
LATITUDE:   56° 54.5' N (  56.90864)          LONGITUDE: 158° 41.0' W (-158.68350)


The primary benchmark is a flange-encased rod set near the southern end of the
old Meshik Village, 93 m (305 ft) ESE of the high water and cliff line, 72.72 m
(238.6 ft) SSW of benchmark 946 4075 C, 66.15 m (217.0 ft) ENE of benchmark 946
4075 A, 45.46 m (149.1 ft) SW of the SW corner of a shed to the south of the red
building with a fuel tank, and 40.69 m (133.5 ft) SE of the NE corner of a
concrete slab fuel tank foundation with no tank. The datum point is set 10 cm
(0.3 ft) below grade, being the top of a stainless steel rod driven 19.5 m (64.0
ft) to refusal, in a sleeve extending to a depth of 1.0 m (3.3 ft) and encased
in an 8-inch National Ocean Service logo cap.

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

                                                                                
Station ID: 9464075                         PUBLICATION DATE:  01/04/2018
Name:       MESHIK, PORT HEIDEN                               
            AK
NOAA Chart: 16343                           Latitude:   56° 54.5' N (  56.90825)
USGS Quad:  CHIGNIK D-3                     Longitude: 158° 41.1' W (-158.68492)


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


                         BENCH MARK STAMPING:  4075 A 2013
                         DESIGNATION:          946 4075 A

MONUMENTATION:           Flange-encased Rod                    VM#:        22542
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID:        
LATITUDE:   56° 54.5' N (  56.90828)          LONGITUDE: 158° 41.1' W (-158.68439)


The benchmark is a flange-enased rod set near the southern end of the old Meshik
Village, 66.15 m (217.0 ft) WSW of benchmark 946 4075 B, 62.68 m (205.6 ft) SSE
of the NE corner of a concrete slab in the middle of the road, 49 m (161 ft) ESE
of the high water and cliff line, and 6.34 m (20.8 ft) NNW of the southernmost
edge of a mound which the benchmark is set on. The datum point is set 10 cm (0.3
ft) below grade, being the top of a stainless steel rod driven 18.3 m (60.0 ft)
to refusal, in a sleeve extending to a depth of 1.0 m (3.3 ft) and encased in an
8-inch National Ocean Service logo cap.

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

                                                                                
Station ID: 9464075                         PUBLICATION DATE:  01/04/2018
Name:       MESHIK, PORT HEIDEN                               
            AK
NOAA Chart: 16343                           Latitude:   56° 54.5' N (  56.90825)
USGS Quad:  CHIGNIK D-3                     Longitude: 158° 41.1' W (-158.68492)


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


                         BENCH MARK STAMPING:  4075 C 2013
                         DESIGNATION:          946 4075 C

MONUMENTATION:           Flange-encased Rod                    VM#:        22543
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   56° 54.6' N (  56.90928)          LONGITUDE: 158° 41.0' W (-158.68325)


The benchmark is a flange-encased rod set north of an intersection of two gravel
driveways in the old Meshik Village, 105 m (344 ft) ESE of the high water and
cliff line, 75.59 m (248.0 ft) NW of benchmark 946 4075 D, 72.72 m (238.6 ft)
NNE of benchmark 946 4075 B, 72.64 m (238.3 ft) SSW of the SE corner of a teal
house, 33.62 m (110.3 ft) NW of the NW corner of a red house, and 9.75 m (32.0
ft) NNE of the gravel edge of the driveway.  The datum point is set 10 cm (0.3
ft) below grade, being the top of a stainless steel rod driven 18.3 m (60.0 ft)
to refusal, in a sleeve extending to a depth of 1.0 m (3.3 ft) and encased in an
8-inch National Ocean Service logo cap.

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

                                                                                
Station ID: 9464075                         PUBLICATION DATE:  01/04/2018
Name:       MESHIK, PORT HEIDEN                               
            AK
NOAA Chart: 16343                           Latitude:   56° 54.5' N (  56.90825)
USGS Quad:  CHIGNIK D-3                     Longitude: 158° 41.1' W (-158.68492)


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


                         BENCH MARK STAMPING:  4075 D 2013
                         DESIGNATION:          946 4075 D

MONUMENTATION:           Flange-encased Rod                    VM#:        22544
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID:        
LATITUDE:   56° 54.5' N (  56.90875)          LONGITUDE: 158° 40.9' W (-158.68242)


The benchmark is a flange-encased rod set at the southern end of the old Meshik
Village, 84.42 m (277.0 ft) WSW of benchmark 946 4075 E, 75.59 m (248.0 ft) SE
of benchmark 946 4075 C, 30.77 m (101.0 ft) SSE of the SE corner of a red house,
29.72 m (97.5 ft) SE of the NE corner of a wooden shed south of the red house,
and 6.83 m (22.4 ft) north of the southernmost edge of the tundra mound on which
the benchmark is set. The datum point is set 10 cm (0.3 ft) below grade, being
the top of a stainless steel rod driven 18.3 m (60.0 ft) to refusal, in a sleeve
extending to a depth of 1.0 m (3.3 ft) and encased in an 8-inch National Ocean
Service logo cap.

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

                                                                                
Station ID: 9464075                         PUBLICATION DATE:  01/04/2018
Name:       MESHIK, PORT HEIDEN                               
            AK
NOAA Chart: 16343                           Latitude:   56° 54.5' N (  56.90825)
USGS Quad:  CHIGNIK D-3                     Longitude: 158° 41.1' W (-158.68492)


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


                         BENCH MARK STAMPING:  4075 E 2013
                         DESIGNATION:          946 4075 E

MONUMENTATION:           Flange-encased Rod                    VM#:        22545
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod in sleeve         OPUS PID:        
LATITUDE:   56° 54.5' N (  56.90906)          LONGITUDE: 158° 40.9' W (-158.68114)


The benchmark is a flange-encased rod set at the southeastern end of the old
Meshik Village, 84.42 m (277.0 ft) ENE of benchmark 946 4075 D, 52.25 m (171.4
ft) SE of the southernmost corner of a blue house, 51.89 m (170.2 ft) SSE of the
SE corner of a blue house, 18.80 m (61.7 ft) SSW of the Goldfish Lake high water
mark. The datum point is set 11 cm (0.4 ft) below grade, being the top of a
stainless steel rod driven 18.3 m (60.0 ft) to refusal, in a sleeve extending to
a depth of 1.0 m (3.3 ft) and encased in an 8-inch National Ocean Service logo
cap.

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

                                                                                
Station ID: 9464075                         PUBLICATION DATE:  01/04/2018
Name:       MESHIK, PORT HEIDEN                               
            AK
NOAA Chart: 16343                           Latitude:   56° 54.5' N (  56.90825)
USGS Quad:  CHIGNIK D-3                     Longitude: 158° 41.1' W (-158.68492)


                            T I D A L   D A T U M S 


Tidal datums at MESHIK, PORT HEIDEN based on:

     LENGTH OF SERIES:      30 DAYS
     TIME PERIOD:           Sep 12 2013 - Oct 11 2013
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9463502 PORT MOLLER, BRISTOL BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  3.540
     MEAN HIGH WATER                            MHW    =  3.186
     MEAN SEA LEVEL                             MSL    =  1.958
     MEAN TIDE LEVEL                            MTL    =  1.946
     MEAN LOW WATER                             MLW    =  0.707
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     4075 B 2013                                 8.277    5.092
     4075 A 2013                                 7.851    4.666
     4075 C 2013                                 7.515    4.329
     4075 D 2013                                 7.597    4.411
     4075 E 2013                                 7.176    3.991


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

                                                                                
Station ID: 9464075                         PUBLICATION DATE:  01/04/2018
Name:       MESHIK, PORT HEIDEN                               
            AK
NOAA Chart: 16343                           Latitude:   56° 54.5' N (  56.90825)
USGS Quad:  CHIGNIK D-3                     Longitude: 158° 41.1' W (-158.68492)


                             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.