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

                                                   PUBLICATION DATE:  02/07/1985
Station ID: 9415307                                SUPERCEDED DATE:   04/21/2003
Name:       MEINS LANDING, MONTEZUMA SLOUGH, SUISUN BAY       
            CALIFORNIA
NOAA Chart: 18656                                  Latitude:         38°  8.2' N
USGS Quad:  DENVERTON                              Longitude:       121° 54.4' W


To reach the tidal bench marks proceed 0.2 mile (0.3 km) NE along Collinsville
Road from the Montezuma Union Elementary School at Birds Landing, then 2.4 miles
(3.9 km) west along a county paved road.  The bench marks are located along
Birds Landing Road east of houses and a barn.  The tide gage and staff were
located on the end of the dock at Wards Landing.


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


                 PRIMARY BENCH MARK STAMPING:  5307 D 1977

MONUMENTATION:           Survey Disk                               VM#:     8649
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is on the north side of the road across from a row of cottages,
600.0 feet (182.9 m) south of the end of Meins Landing Road, 195.0 feet (59.4 m)
ESE from the SE corner of the barn, 79.0 feet (24.1 m) ENE from the front door
of the gabled house, 41.0 feet (12.5 m) ENE from the centerline of Meins Landing
Road, 2.5 feet (0.8 m) NNW from telephone pole along the side lane on the south
side of Meins Landing Road and 0.3 foot (0.1 m) below grade.  The bench mark is
on a rod driven 53.0 feet (16.2 m) and inside a PVC pipe.



                         BENCH MARK STAMPING:  NO 4 1949

MONUMENTATION:           Survey Disk                               VM#:     8648
AGENCY:                                                            PID#:  JS2012
SETTING CLASSIFICATION:  Concrete Post


The bench mark is at a point where powerline extends over and across the road,
103.5 feet (31.5 m) NE of Bench Mark NO 3 1949, 90.0 feet (27.4 m) east of the
center of a triangle formed by the junction of the main road with a gravel
roading leading NW to the boat landings, 34.5 feet (10.5 m) east of the
centerline of the road, 4.1 feet (1.2 m) north of a powerline pole, 1.7 feet
(0.5 m) west of the fence line, level with the road, and on concrete post
projecting 0.2 foot (0.06 m) above the ground.

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

                                                   PUBLICATION DATE:  02/07/1985
Station ID: 9415307                                SUPERCEDED DATE:   04/21/2003
Name:       MEINS LANDING, MONTEZUMA SLOUGH, SUISUN BAY       
            CALIFORNIA
NOAA Chart: 18656                                  Latitude:         38°  8.2' N
USGS Quad:  DENVERTON                              Longitude:       121° 54.4' W


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


                         BENCH MARK STAMPING:  5307 E 1977

MONUMENTATION:           Survey Disk                               VM#:     8650
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 20.0 feet (6.1 m) NE from the centerline of Meins Landing
Road, 7.5 feet (2.3 m) NNW from a telephone pole, 3.0 feet (0.9 m) SE from the
first fence post NW of the telephone pole, and 0.1 foot (0.03 m) below the
grade.



                         BENCH MARK STAMPING:  Q 555 1956

MONUMENTATION:           Survey Disk                               VM#:     8651
AGENCY:                                                            PID#:  JS2011
SETTING CLASSIFICATION:  Concrete Post


The bench mark is 168.4 feet (51.3 m) east of and across the road from the east
corner of the caretaker cottage, 42.0 feet (12.8 m) NE of the centerline of the
road, 1.5 feet (0.5 m) west of the fence cover post, 1.3 feet (0.4 m) SE of a
witness post, 1.2 feet (0.4 m) SW of the fence, and 2.0 feet (0.6 m) above the
road on top of a concrete post projecting 0.2 foot (0.06 m) above the ground.

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

                                                   PUBLICATION DATE:  02/07/1985
Station ID: 9415307                                SUPERCEDED DATE:   04/21/2003
Name:       MEINS LANDING, MONTEZUMA SLOUGH, SUISUN BAY       
            CALIFORNIA
NOAA Chart: 18656                                  Latitude:         38°  8.2' N
USGS Quad:  DENVERTON                              Longitude:       121° 54.4' W


                            T I D A L   D A T U M S 


Tidal datums at MEINS LANDING, MONTEZUMA SLOUGH, SUISUN BAY based on:

     LENGTH OF SERIES:      12 MONTHS
     TIME PERIOD:           FEBRUARY 1978-JANUARY 1979
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  9415144 PORT CHICAGO


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

     HIGHEST OBSERVED WATER LEVEL (02/07/1978)         =   6.55
     MEAN HIGHER HIGH WATER                     MHHW   =   4.90
     MEAN HIGH WATER                            MHW    =   4.39
     MEAN TIDE LEVEL                            MTL    =   2.54
   * NATIONAL GEODETIC VERTICAL DATUM           NGVD29 =   1.69
     MEAN LOW WATER                             MLW    =   0.69
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (12/06/1978)         =  -0.94

   * NGVD reference based on adjustment of 1964 and NOS levels of 1977. 
North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     5307 D 1977                                19.45     15.06
     NO 4 1949                                   9.83      5.44
     5307 E 1977                                 8.04      3.65
     Q 555 1956                                 15.80     11.41


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

                                                   PUBLICATION DATE:  02/07/1985
Station ID: 9415307                                SUPERCEDED DATE:   04/21/2003
Name:       MEINS LANDING, MONTEZUMA SLOUGH, SUISUN BAY       
            CALIFORNIA
NOAA Chart: 18656                                  Latitude:         38°  8.2' N
USGS Quad:  DENVERTON                              Longitude:       121° 54.4' 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.