U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


To reach the tide station from the entrance gate for Naval Air Station Whidbey
Island on Langley Boulevard, proceed north on Langley Boulevard for 0.7 km (0.4
mi) to the intersection with Midway Street, turn left and proceed west on Midway
Street for 0.8 km (0.5 mi) to the T intersection with North Saratoga Street,
turn right and proceed north on North Saratoga Street for 0.6 km (0.4 mi) to the
parking lot for the Nor Wester building on the left, proceed on foot 0.1 km (0.1
mi) west across the lawn from the parking lot and then down the grassy hill to
the beach below, turn left and proceed SW along the beach 0.2 km (0.1 mi) to the
tide station.  The bench marks are above the beach on the bluff and along Midway
Street.


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


                 PRIMARY BENCH MARK STAMPING:  7973 A 2016
                         DESIGNATION:          944 7973 A

MONUMENTATION:           Flange-encased Rod                    VM#:        21932
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID#: BBFF69
LATITUDE:   48° 20.6' N (  48.34389)          LONGITUDE: 122° 40.9' W (-122.68178)


The primary bench mark is a flange encased rod set in the grass at the top of
the bluff above the beach, 64.54 m (211.7 ft) W of the SW post of a covered
bridge for a walking path, 55.40 m (181.8 ft) ESE of a 21 cm (8 inches) diameter
monitoring well near the beach, 41.52 m (136.2 ft) NNW of the W set of double
doors on the N side of the nor wester building, 7.62 m (25.0 ft) WNW of the SW
corner of a concrete pad for a viewing scope, and 0.42 m (1.4 ft) ESE of a
carsonite witness post.  The datum point is set 3 cm (1 inch) below ground,
being the top of a stainless steel rod driven 6.7 m (22.0 ft) to refusal, in a
sleeve extending to a depth of 0.91 m (3.0 ft) and encased in a 5-inch (13 cm)
nos logo cap with concrete kick block.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


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


                         BENCH MARK STAMPING:  7973 B 2016
                         DESIGNATION:          944 7973 B

MONUMENTATION:           Tidal Station disk                    VM#:        21933
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Concrete loading dock                 OPUS PID:        
LATITUDE:   48° 20.6' N (  48.34303)          LONGITUDE: 122° 40.9' W (-122.68147)


The bench mark is a disk set in the concrete loading dock of the Nor Wester
building, 28.06 m (92.1 ft) WNW of a street light pole, 12.97 m (42.6 ft) W of
the center of a storm drain, 9.64 m (31.6 ft) NNW of the S end of the wall, 5.71
m (18.7 ft) NNW of the edge of loading dock, and 1.29 m (4.2 ft) SW of the S
side of a door.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


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


                         BENCH MARK STAMPING:  CHAPEL NO 2 WWB 1972
                         DESIGNATION:          CHAPEL 2 1974

MONUMENTATION:           Not specified (see descriptive text)  VM#:        21934
AGENCY:                                                        IDB PID#:  TR1395
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   48° 20.3' N (  48.33875)          LONGITUDE: 122° 40.5' W (-122.67483)


The bench mark is a flat disk set in a concrete monument, 15.66 m (51.4 ft) NE
of a street light pole, 6.01 m (19.7 ft) NW of S most wood sign post, 4.79 m
(15.7 ft) WSW of a street light pole, 3.30 m (10.8 ft) N of the NW corner of a
concrete utility pad, 3.15 m (10.3 ft) E of a paved fitness trail, and 0.1 m
(0.3 ft) below the ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


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


                         BENCH MARK STAMPING:  NO 2 1951
                         DESIGNATION:          LOG HOUSE RM 2

MONUMENTATION:           Reference Mark disk                   VM#:        21935
AGENCY:                  US Coast and Geodetic Survey          IDB PID#:  TR0403
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   48° 20.5' N (  48.34150)          LONGITUDE: 122° 41.2' W (-122.68597)


The bench mark is a disk in a concrete monument set among thorn bushes, 17.14 m
(56.2 ft) W of a 0.45 m (1.5 ft) diameter evergreen tree, 16.05 m (52.7 ft) N of
a wood fence, 12.39 m (40.6 ft) NW of the SE corner of a concrete pad.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


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


                         BENCH MARK STAMPING:  LOG HOUSE 2 1969
                         DESIGNATION:          LOG HOUSE 2

MONUMENTATION:           Triangulation Station disk            VM#:        21936
AGENCY:                  US Coast and Geodetic Survey          IDB PID#:  TR0404
SETTING CLASSIFICATION:  Concrete slab                         OPUS PID:        
LATITUDE:   48° 20.5' N (  48.34147)          LONGITUDE: 122° 41.2' W (-122.68592)


The bench mark is a disk set in a concrete pad 11.32 m (37.1 ft) N of a wood
fence, 11.32 m (37.1 ft) SW of a 0.45 m (1.5 ft) diameter evergreen tree, and
5.33 m (17.5 ft) W of the SE corner of concrete pad.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


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


                         BENCH MARK STAMPING:  LOG HOUSE 2 NO 3 1969
                         DESIGNATION:          LOG HOUSE 2 RM 3

MONUMENTATION:           Reference Mark disk                   VM#:        21937
AGENCY:                  US Coast and Geodetic Survey          IDB PID#:  TR0405
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   48° 20.5' N (  48.34142)          LONGITUDE: 122° 41.2' W (-122.68600)


The bench mark is a disk set in a concrete monument in grass, 16.69 m (54.8 ft)
WSW of a 0.45 m (1.5 ft) diameter evergreen tree, 7.16 m (23.5 ft) WSW of the SE
corner of concrete pad, and 5.19 m (17.0 ft) N of a wood fence.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


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


                         BENCH MARK STAMPING:  Z 343 1952
                         DESIGNATION:          Z 343

MONUMENTATION:           Bench Mark disk                       VM#:        21938
AGENCY:                  US Coast and Geodetic Survey          IDB PID#:  TR0411
SETTING CLASSIFICATION:  Utility access cover pad              OPUS PID:        
LATITUDE:   48° 20.3' N (  48.33758)          LONGITUDE: 122° 40.1' W (-122.66764)


The bench mark is a disk set in a concrete slab for a sewer manhole, 47.98 m
(157.4 ft) ESE of the SE corner of the region legal service office building,
31.95 m (104.8 ft) N of the centerline of an unnamed road, 28.52 m (93.6 ft) SSE
of a 21 cm (8 inches) diameter monitoring well number 311, 24.67 m (80.9 ft) W
of a 21 cm (8 inches) diameter monitoring well number ff3 350, and 0.76 m (2.5
ft) E of the center of a 0.54 m (1.8 ft) diameter sanitary sewer manhole.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  8 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


                            T I D A L   D A T U M S 


Tidal datums at NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           June 2016 - August 2016
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9449880 FRIDAY HARBOR, SAN JUAN CHANNEL


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.267
     MEAN HIGH WATER                            MHW    =  2.077
     MEAN TIDE LEVEL                            MTL    =  1.372
     MEAN SEA LEVEL                             MSL    =  1.353
     MEAN LOW WATER                             MLW    =  0.667
     North American Vertical Datum              NAVD88 =  0.100
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     7973 A 2016                                 9.552    7.475
     7973 B 2016                                11.516    9.439
     CHAPEL NO 2 WWB 1972                       20.064   17.987
     NO 2 1951                                  23.321   21.244
     LOG HOUSE 2 1969                           22.482   20.405
     LOG HOUSE 2 NO 3 1969                      22.395   20.318
     Z 343 1952                                 11.276    9.199


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  9 of  9

                                                                                
Station ID: 9447973                         PUBLICATION DATE:  11/15/2016
Name:       NAS WHIDBEY ISLAND, STRAIT OF JAUN DE FUCA        
            WA
NOAA Chart: 18429                           Latitude:   48° 20.6' N (  48.34283)
USGS Quad:  OAK HARBOR                      Longitude: 122° 41.1' W (-122.68583)


                             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.