U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  6

                                                   PUBLICATION DATE:  08/20/1991
Station ID: 8747437                                SUPERCEDED DATE:   04/21/2003
Name:       BAY WAVELAND YACHT CLUB, ST. LOUIS BAY            
            MISSISSIPPI
NOAA Chart: 11371                                  Latitude:         30° 19.5' N
USGS Quad:  BAY ST. LOUIS                          Longitude:        89° 19.5' W


To reach the tidal bench marks from the intersection of U.S. Highway 90 and
North Beach Boulevard at the west end of the U.S. Highway 90 bridge over St.
Louis Bay, proceed 0.4 mile (0.6 km) north on North Beach Boulevard to Bay
Waveland Yacht Club.  The bench marks are in the vicinity of the yacht club and
near U.S. Highway 90.  The tide gage and staff are at the inside corner of the
L-shaped pier on St. Louis Bay.


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


                 PRIMARY BENCH MARK STAMPING:  7437 A 1978

MONUMENTATION:           Survey Disk                               VM#:      797
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Stainless Steel Rod


The primary bench mark is next to a creosote pile supporting the club house
porch at the foot of the pier, on the NE edge of a concrete patio beneath a
second story deck, 47.5 feet (14.5 m) NW of the NW corner of the concrete slab
of the flag pole in front of the club house, and 13.9 feet (4.2 m) east of the
NE corner of the second story of the club house.  The bench mark is 0.5 foot
(0.2 m) below ground level, crimped to the top of a stainless steel rod driven
to an unspecified depth, and encased in a 4-inch PVC pipe and concrete
kickblock.



                         BENCH MARK STAMPING:  NO 1 1968

MONUMENTATION:           Survey Disk                               VM#:      798
AGENCY:                                                            PID#:  BH0937
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set in a concrete sea wall at the entrance of Bay Waveland
Yacht Club, 39 feet (12 m) NW of the center of the entrance to the yacht club,
28 feet (9 m) NW of the NW steel gate post at the entrance to the yacht club,
and 18 feet (5 m) NE of the centerline of North Beach Boulevard.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  6

                                                   PUBLICATION DATE:  08/20/1991
Station ID: 8747437                                SUPERCEDED DATE:   04/21/2003
Name:       BAY WAVELAND YACHT CLUB, ST. LOUIS BAY            
            MISSISSIPPI
NOAA Chart: 11371                                  Latitude:         30° 19.5' N
USGS Quad:  BAY ST. LOUIS                          Longitude:        89° 19.5' W


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


                         BENCH MARK STAMPING:  NO 2 1968

MONUMENTATION:           Survey Disk                               VM#:      799
AGENCY:                                                            PID#:  BH0936
SETTING CLASSIFICATION:  Concrete Sea Wall


The bench mark is set in the south end of a concrete sea wall, 0.4 mile (0.6 km)
north of U.S. Highway 90 on North Beach Boulevard, 327 feet (100 m) SE of the
center of the entrance to the yacht club, 18 feet (5 m) NE of the centerline of
North Beach Boulevard, and 3.2 feet (1.0 m) NW of the SE end of the sea wall.



                         BENCH MARK STAMPING:  7437 C 1978

MONUMENTATION:           Survey Disk                               VM#:      802
AGENCY:                                                            PID:         
SETTING CLASSIFICATION:  Stainless Steel Rod


The bench mark is next to a utility pole in a park directly across the street
from the yacht club, 51.5 feet (15.7 m) west of an old sea wall corner on the
north side of the gate to the yacht club, and 25.0 feet (7.6 m) SW of the
centerline of North Beach Boulevard.  The bench mark is 0.8 foot (0.2 m) below
ground level, crimped to the top of a stainless steel rod driven to an
unspecified depth, and encased in a 4-inch PVC pipe and concrete kickblock.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  6

                                                   PUBLICATION DATE:  08/20/1991
Station ID: 8747437                                SUPERCEDED DATE:   04/21/2003
Name:       BAY WAVELAND YACHT CLUB, ST. LOUIS BAY            
            MISSISSIPPI
NOAA Chart: 11371                                  Latitude:         30° 19.5' N
USGS Quad:  BAY ST. LOUIS                          Longitude:        89° 19.5' W


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


                         BENCH MARK STAMPING:  WEST 1954

MONUMENTATION:           Survey Disk                               VM#:     1805
AGENCY:                                                            PID#:  BH0934
SETTING CLASSIFICATION:  Concrete Bridge Sidewalk


The bench mark is set in the top of the north concrete sidewalk of the US
highway 90 bridge over St. Louis Bay, about 405 feet (123 m) east of the west
end of the bridge, 13 feet (4 m) north of the centerline of the northbound lanes
of the bridge, 6.0 feet (1.8 m) east of the third light pole from the west end
of the bridge, 1.0 foot (0.3 m) north of the south edge of the sidewalk, and
about 0.5 foot (0.2 m) above the level of the bridge floor.



                         BENCH MARK STAMPING:  Z 214 1963

MONUMENTATION:           Survey Disk                               VM#:     1806
AGENCY:                                                            PID#:  BH0935
SETTING CLASSIFICATION:  Copper-clad Steel Rod


The bench mark is 316.5 feet (96.5 m) NW of the west end of the north concrete
bannister of the US highway 90 bridge over St. Louis Bay, 103 feet (31 m) east
of the centerline of North Beach Boulevard, 80.5 feet (24.5 m) north of the
centerline of the westbound lane of the highway, 3 feet (1 m) west of powerline
pole #74 and 2 feet (1 m) east of a metal witness post.  The bench mark is 6
feet (2 m) below the level of the highway, crimped to a copper-clad steel rod
driven 76 feet (23 m) to refusal, and encased in a 4-inch tile level with the
ground.  

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  6

                                                   PUBLICATION DATE:  08/20/1991
Station ID: 8747437                                SUPERCEDED DATE:   04/21/2003
Name:       BAY WAVELAND YACHT CLUB, ST. LOUIS BAY            
            MISSISSIPPI
NOAA Chart: 11371                                  Latitude:         30° 19.5' N
USGS Quad:  BAY ST. LOUIS                          Longitude:        89° 19.5' W


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


                         BENCH MARK STAMPING:  S 190 RESET 1976

MONUMENTATION:           Survey Disk                               VM#:    12419
AGENCY:                                                            PID#:  BH0941
SETTING CLASSIFICATION:  Concrete Culvert


The bench mark is set in the top of the east end of the south concrete headwall
for a 5 foot (2 m) concrete pipe culvert with wing walls, about 0.3 mile (0.5
km) west along US Highway 90 from the west end of the bridge over St. Louis Bay,
192 feet (59 m) east of the center step at the entrance to Wayside Shrine at St.
Augustine Seminary, 39.5 feet (12.0 m) south of the centerline of the eastbound
lane of US Highway 90, and 2 feet (1 m) below the level of the highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  6

                                                   PUBLICATION DATE:  08/20/1991
Station ID: 8747437                                SUPERCEDED DATE:   04/21/2003
Name:       BAY WAVELAND YACHT CLUB, ST. LOUIS BAY            
            MISSISSIPPI
NOAA Chart: 11371                                  Latitude:         30° 19.5' N
USGS Quad:  BAY ST. LOUIS                          Longitude:        89° 19.5' W


                            T I D A L   D A T U M S 


Tidal datums at BAY WAVELAND YACHT CLUB, ST. LOUIS BAY based on:

     LENGTH OF SERIES:      11 YEARS
     TIME PERIOD:           1979-1989
     TIDAL EPOCH:           1960-1978
     CONTROL TIDE STATION:  8729840 PENSACOLA, FL


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

     HIGHEST OBSERVED WATER LEVEL (08/22/1969)         =  19.67
     MEAN HIGHER HIGH WATER                     MHHW   =   1.77
     MEAN HIGH WATER                            MHW    =   1.65
     MEAN TIDE LEVEL                            MTL    =   0.89
   * NATIONAL GEODETIC VERTICAL DATUM           NGVD29 =   0.66
     MEAN LOW WATER                             MLW    =   0.12
     MEAN LOWER LOW WATER                       MLLW   =   0.00
     LOWEST  OBSERVED WATER LEVEL (09/02/1985)         =  -3.77

   * NGVD reference based on elevations published in Quad 300892, 1984, and NOS
     leveling of 1990. 
North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In FEET above:

     Stamping or Designation                    MLLW        MHW

     7437 A 1978                                 3.95      2.30
     NO 1 1968                                   5.92      4.27
     NO 2 1968                                   8.39      6.74
     7437 C 1978                                 5.61      3.96
     WEST 1954                                  16.04     14.39
     Z 214 1963                                  8.08      6.43
     S 190 RESET 1976                           10.14      8.49


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

                                                   PUBLICATION DATE:  08/20/1991
Station ID: 8747437                                SUPERCEDED DATE:   04/21/2003
Name:       BAY WAVELAND YACHT CLUB, ST. LOUIS BAY            
            MISSISSIPPI
NOAA Chart: 11371                                  Latitude:         30° 19.5' N
USGS Quad:  BAY ST. LOUIS                          Longitude:        89° 19.5' 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.