U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 8417227                         PUBLICATION DATE:  02/28/2006
Name:       BATH, KENNEBEC RIVER                              
            ME
NOAA Chart: 13293                           Latitude:   43° 55.5' N (  43.92500)
USGS Quad:  BATH                            Longitude:  69° 48.9' W ( -69.81500)


In Bath, Maine from the intersection of US Route 1 and Washington Street,
proceed 1.9 km (1.2 mi) east on Washington Street to 229 Washington Street the
additional Maine Maritime Museum Deering pier and additional parking.   The
bench marks are located around the museum, the pier, and State Road 209. The
tide gauge is located at the SE corner of the pier.


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


                 PRIMARY BENCH MARK STAMPING:  7227 C 2005
                         DESIGNATION:          841 7227 C

MONUMENTATION:           Tidal Station disk                    VM#:        17905
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   43° 53.6' N (  43.89330)          LONGITUDE:  69° 48.9' W ( -69.81500)


The bench mark is set in a rock outcrop just west of Deering pier, 53.50 m
(175.5 ft) WSW of the NW corner of Deering pier, 26.40 m (86.6 ft) west of the
west edge of the Deering pier monument, and 6.61 m (21.7 ft) south of the
centerline of the dirt road leading to the pier. 



                         BENCH MARK STAMPING:  7227 B 2005
                         DESIGNATION:          841 7227 B

MONUMENTATION:           Tidal Station disk                    VM#:        17906
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete slab                         OPUS PID:        
LATITUDE:   43° 53.6' N (  43.89330)          LONGITUDE:  69° 49.0' W ( -69.81670)


The bench mark is set in the NE corner of a concrete slab supporting an electric
generator on the south side of the Maritime Museum, 21.00 m (68.9 ft) north of a
light pole, 2.78 m (9.1 ft) SW of the SW corner of the wooden loading dock, and
0.16 m (0.5 ft) SW of the NE corner of the concrete slab. 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 8417227                         PUBLICATION DATE:  02/28/2006
Name:       BATH, KENNEBEC RIVER                              
            ME
NOAA Chart: 13293                           Latitude:   43° 55.5' N (  43.92500)
USGS Quad:  BATH                            Longitude:  69° 48.9' W ( -69.81500)


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


                         BENCH MARK STAMPING:  7227 A 2005
                         DESIGNATION:          841 7227 A

MONUMENTATION:           Tidal Station disk                    VM#:        17907
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   43° 53.6' N (  43.89330)          LONGITUDE:  69° 48.9' W ( -69.81500)


The bench mark is set in a rock outcrop east of the main building of the
Maritime Museum, 13.80 m (45.3 ft) east of the NE corner of the building, 7.22 m
(23.7 ft) south of the south edge of a sidewalk, and 2.27 m (7.4 ft) SW of the
SW corner of a white wooden building. 



                         BENCH MARK STAMPING:  7227 D 2005
                         DESIGNATION:          841 7227 D

MONUMENTATION:           Tidal Station disk                    VM#:        17908
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   43° 53.6' N (  43.89330)          LONGITUDE:  69° 49.0' W ( -69.81670)


The bench mark is set in a rock outcrop on the north side of the main building
of the Maritime Museum, 10.89 m (35.7 ft) NNW of the NW corner of the building,
2.64 m (8.7 ft) east of the edge of the curb on the entrance drive, and 0.57 m
(1.9 ft) west of the SW corner of the Mould Loft (building 247).

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 8417227                         PUBLICATION DATE:  02/28/2006
Name:       BATH, KENNEBEC RIVER                              
            ME
NOAA Chart: 13293                           Latitude:   43° 55.5' N (  43.92500)
USGS Quad:  BATH                            Longitude:  69° 48.9' W ( -69.81500)


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


                         BENCH MARK STAMPING:  A 97 1943
                         DESIGNATION:          A 97

MONUMENTATION:           Bench Mark disk                       VM#:        17909
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  OB0199
SETTING CLASSIFICATION:  Rock outcrop                          OPUS PID:        
LATITUDE:   43° 53.7' N (  43.89500)          LONGITUDE:  69° 49.2' W ( -69.82000)


The bench mark is a disk set in a rock outcrop near the intersection of State
Highway 209 and Marshall Street, 31.00 m (101.7 ft) SSW of the centerline of
Mitchell Road, 24.40 m (80.1 ft) NW of the junction of Marshall Street, 8.72 m
(28.6 ft) west of the centerline of State Highway 209, and 2.8 m (9.2 ft) above
the level of the highway. 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 8417227                         PUBLICATION DATE:  02/28/2006
Name:       BATH, KENNEBEC RIVER                              
            ME
NOAA Chart: 13293                           Latitude:   43° 55.5' N (  43.92500)
USGS Quad:  BATH                            Longitude:  69° 48.9' W ( -69.81500)


                            T I D A L   D A T U M S 


Tidal datums at BATH, KENNEBEC RIVER based on:

     LENGTH OF SERIES:      38 Days
     TIME PERIOD:           July 21, 2005 - August 27, 2005
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8418150 PORTLAND, CASCO BAY


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

     MEAN HIGHER HIGH WATER                     MHHW   =  2.261
     MEAN HIGH WATER                            MHW    =  2.157
     MEAN SEA LEVEL                             MSL    =  1.131
     MEAN TIDE LEVEL                            MTL    =  1.114
     MEAN LOW WATER                             MLW    =  0.072
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     7227 C 2005                                 5.342    3.185
     7227 B 2005                                 9.615    7.459
     7227 A 2005                                 6.180    4.023
     7227 D 2005                                10.161    8.004
     A 97 1943                                  27.581   25.424


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

                                                                                
Station ID: 8417227                         PUBLICATION DATE:  02/28/2006
Name:       BATH, KENNEBEC RIVER                              
            ME
NOAA Chart: 13293                           Latitude:   43° 55.5' N (  43.92500)
USGS Quad:  BATH                            Longitude:  69° 48.9' W ( -69.81500)


                             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.