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

                                                                                
Station ID: 8761426                         PUBLICATION DATE:  03/09/2004
Name:       GREENS DITCH, LAKE ST. CATHERINE                  
            LA
NOAA Chart: 11369                           Latitude:   30°  6.7' N (  30.11170)
USGS Quad:  CHEF MENTEUR                    Longitude:  89° 45.6' W ( -89.76000)


To reach the tidal bench marks from the SW end of the U.S. Highway 90 bridge
over The Rigolets, proceed SW on U.S. Highway 90 for 7.1 km (4.4 mi) to the All
in the Family Camp on the left.  The bench marks are in the vicinity of the camp
and along U.S. Highway 90.  The tide gage and staff was located at the NE corner
of the dock at the All in the Family Camp.


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


                 PRIMARY BENCH MARK STAMPING:  1426A 1982
                         DESIGNATION:          876 1426 A

MONUMENTATION:           Tidal Station disk                    VM#:         6712
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  6.7' N (  30.11170)          LONGITUDE:  89° 45.6' W ( -89.76000)


The primary bench mark is a disk located near the All in the Family camp, 69 m
(228 ft) east of the centerline of U.S. Highway 90, 27 m (88 ft) west of the
approximate high water mark of the west shore of Lake St. Catherine, 13 m (42
ft) WSW of a small frame pole house, 5 m (16 ft) north of the north side of the
All in the Family Camp, and 2 m (5 ft) east of a 0.21 m (0.7 ft) diameter
utility pole.  The bench mark is set 0.1 m (0.3 ft) below gradel, crimped to the
top of a stainless steel rod driven 18.3 m (60 ft) to substantial resistance,
and encased in a 4-inch PVC collar and concrete kickblock.

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

                                                                                
Station ID: 8761426                         PUBLICATION DATE:  03/09/2004
Name:       GREENS DITCH, LAKE ST. CATHERINE                  
            LA
NOAA Chart: 11369                           Latitude:   30°  6.7' N (  30.11170)
USGS Quad:  CHEF MENTEUR                    Longitude:  89° 45.6' W ( -89.76000)


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


                         BENCH MARK STAMPING:  E 92 1938
                         DESIGNATION:          E 92

MONUMENTATION:           Bench Mark disk                       VM#:         6710
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  BH1147
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30°  7.2' N (  30.12000)          LONGITUDE:  89° 45.8' W ( -89.76330)


The bench mark is a disk set in a concrete monument projecting 0.21 m (0.7 ft)
above the ground surface located in the yard of a one-story frame house, 0.6 km
(0.4 mi) north of bench mark E 193 1963, 40.81 m (133.9 ft) east of the
centerline of U.S. Highway 90, 18.59 m (61.0 ft) north of the centerline of the
driveway to the house, 7.01 m (23.0 ft) NNW of the NW corner of a mobile home,
3.69 m (12.1 ft) south of the center of a driveway, 0.30 m (1.0 ft) west of a
witness post, and 1.58 m (5.2 ft) below the highway. 

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

                                                                                
Station ID: 8761426                         PUBLICATION DATE:  03/09/2004
Name:       GREENS DITCH, LAKE ST. CATHERINE                  
            LA
NOAA Chart: 11369                           Latitude:   30°  6.7' N (  30.11170)
USGS Quad:  CHEF MENTEUR                    Longitude:  89° 45.6' W ( -89.76000)


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


                         BENCH MARK STAMPING:  E 193 1963
                         DESIGNATION:          E 193

MONUMENTATION:           Bench Mark disk                       VM#:         6711
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:  BH1145
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   30°  6.8' N (  30.11330)          LONGITUDE:  89° 45.7' W ( -89.76170)


The bench mark is a disk located south of the All in the Family camp, 40 m (132
ft) east of the centerline of U.S. Highway 90, 26.09 (85.6 ft) west of the NW
cornerof a house, 11.00 m (36.1 ft) north of the centerline of a driveway, 0.79
m (2.6 ft) west of the utility pole #515 with a transformer, and 2.29 m (7.5 ft)
below the highway.  The bench mark is set 0.2 m (0.7 ft) below the ground,
crimped to the top of a copper-clad steel rod driven 19.5 m (64 ft), and encased
in a 4-inch tile pipe.

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

                                                                                
Station ID: 8761426                         PUBLICATION DATE:  03/09/2004
Name:       GREENS DITCH, LAKE ST. CATHERINE                  
            LA
NOAA Chart: 11369                           Latitude:   30°  6.7' N (  30.11170)
USGS Quad:  CHEF MENTEUR                    Longitude:  89° 45.6' W ( -89.76000)


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


                         BENCH MARK STAMPING:  1426B 1982
                         DESIGNATION:          876 1426 B

MONUMENTATION:           Tidal Station disk                    VM#:         6713
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  6.7' N (  30.11170)          LONGITUDE:  89° 45.6' W ( -89.76000)


The bench mark is a disk located along the east side of U.S. Highway 90, 63 m
(206 ft) WNW of bench mark 1426A 1982, 27 m (88 ft) south of the centerline of
the shell driveway to the Shining camp house, 22 m (73 ft) NW of a 0.21 m (0.7
ft) diameter utility pole north of the All in the Family camp house, 22 m (71
ft) north of the centerline of the shell driveway to the All in the Family camp
house, and 9 m (31 ft) east of the centerline of U.S. Highway 90.  The bench
mark is set 12 cm (0.4 ft) below grade, crimped to the top of a stainless steel
rod driven 19.5 m (64 ft) to substantial resistance, and encased in a 4-inch PVC
collar and concrete kickblock.



                         BENCH MARK STAMPING:  1426C 1982
                         DESIGNATION:          876 1426 C

MONUMENTATION:           Tidal Station disk                    VM#:         6714
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  6.7' N (  30.11170)          LONGITUDE:  89° 45.6' W ( -89.76000)


The bench mark is a disk located along the west side of U. S. Highway 90, 78 m
(257 ft) NNW of bench mark 1426B 1982, 55 m (179 ft) east of the east shore of
Bayou de Lesaire, 54 m (177 ft) NW of a house trailer, 25 m (81 ft) ENE of a
utility pole, and 16 m (54 ft) west of the centerline of U.S. Highway 90.  The
bench mark is 0.1 m (0.3 ft) below grade, crimped to the top of a stainless
steel rod driven 21.9 m (72 ft) to substantial resistance, and encased in a
4-inch PVC collar and concrete kickblock.

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

                                                                                
Station ID: 8761426                         PUBLICATION DATE:  03/09/2004
Name:       GREENS DITCH, LAKE ST. CATHERINE                  
            LA
NOAA Chart: 11369                           Latitude:   30°  6.7' N (  30.11170)
USGS Quad:  CHEF MENTEUR                    Longitude:  89° 45.6' W ( -89.76000)


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


                         BENCH MARK STAMPING:  1426D 1982
                         DESIGNATION:          876 1426 D

MONUMENTATION:           Tidal Station disk                    VM#:         6715
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30°  6.7' N (  30.11170)          LONGITUDE:  89° 45.6' W ( -89.76000)


The bench mark is a disk located along the east side of U.S. Highway 90, 76 m
(248 ft) NNE of bench mark 1426C 1982, 49 m (162 ft) ENE of utility pole #517 B,
47 m (155 ft) south of utility pole #7 B, 14 m (46 ft) WSW of utility pole #6 E,
and 9 m (29 ft) east of the centerline of U.S. Highway 90.  The bench mark is
set 0.1 m (0.3 ft) below grade, crimped to the top of a stainless steel rod
driven 20.7 m (68 ft) to substantial resistance, and encased in a 4-inch PVC
collar and concrete kickblock.

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

                                                                                
Station ID: 8761426                         PUBLICATION DATE:  03/09/2004
Name:       GREENS DITCH, LAKE ST. CATHERINE                  
            LA
NOAA Chart: 11369                           Latitude:   30°  6.7' N (  30.11170)
USGS Quad:  CHEF MENTEUR                    Longitude:  89° 45.6' W ( -89.76000)


                            T I D A L   D A T U M S 


Tidal datums at GREENS DITCH, LAKE ST. CATHERINE based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           December 1982 - November 1983
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8761927 USCG NEW CANAL STA., LAKE PONT.


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

     HIGHEST OBSERVED WATER LEVEL (02/27/1983)         =  0.807
     MEAN HIGHER HIGH WATER                     MHHW   =  0.239
     MEAN HIGH WATER                            MHW    =  0.231
     MEAN SEA LEVEL                             MSL    =  0.121
     MEAN TIDE LEVEL                            MTL    =  0.117
     MEAN LOW WATER                             MLW    =  0.004
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     North American Vertical Datum              NAVD88 = -0.099
     LOWEST  OBSERVED WATER LEVEL (02/03/1983)         = -0.443

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     1426A 1982                                  0.414    0.183
     E 92 1938                                   1.048    0.817
     E 193 1963                                  0.925    0.694
     1426B 1982                                  2.909    2.678
     1426C 1982                                  2.882    2.651
     1426D 1982                                  3.122    2.891


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

                                                                                
Station ID: 8761426                         PUBLICATION DATE:  03/09/2004
Name:       GREENS DITCH, LAKE ST. CATHERINE                  
            LA
NOAA Chart: 11369                           Latitude:   30°  6.7' N (  30.11170)
USGS Quad:  CHEF MENTEUR                    Longitude:  89° 45.6' W ( -89.76000)


                             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.