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

                                                                                
Station ID: 8761955                         PUBLICATION DATE:  12/20/2011
Name:       CARROLLTON, MISSISSIPPI RIVER                     
            LA
NOAA Chart: 11368                           Latitude:   29° 56.0' N (  29.93289)
USGS Quad:  NEW ORLEANS WEST                Longitude:  90°  8.1' W ( -90.13547)


To reach the tidal bench marks from the intersection of Carrollton Avenue and
River Road in the Carrollton section of New Orleans, proceed south on River Road
for 1.2 km (0.75 mi) to the New Orleans District Corps of Engineers reservation
along the Mississippi River.  The bench marks are located at the north and south
ends of the Corps of Engineers office building.  The tide gage was located on
the north side of the large pier along the river near the south end of the
building.


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


                 PRIMARY BENCH MARK STAMPING:  DISTRICT 1 A
                         DESIGNATION:          DISTRICT 1 A

MONUMENTATION:           Flange-encased Rod                    VM#:        18019
AGENCY:                  US Army Corps of Engineers (USE)      IDB PID#:  AU2196
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: AU2196
LATITUDE:   29° 55.9' N (  29.93144)          LONGITUDE:  90°  8.0' W ( -90.13397)


The primary bench mark is a flange-encased rod located 43.2 m (141.7 ft) NW of
power pole number TG89, 19.1m (62.7 ft) north of the centerline of the west
railroad track running on the west side of Leake Avenue, 5.9 m (19.4 ft) WSW of
the SE corner of the chain link fence surrounding the USACE property, and 5.5 m
(18.0 ft) south of a carsonite witness post.  The datum point is set 10 cm (0.32
ft) below ground, being the top of a stainless steel rod driven 18.2 m (59.7 ft)
depth and encased in PVC pipe.

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

                                                                                
Station ID: 8761955                         PUBLICATION DATE:  12/20/2011
Name:       CARROLLTON, MISSISSIPPI RIVER                     
            LA
NOAA Chart: 11368                           Latitude:   29° 56.0' N (  29.93289)
USGS Quad:  NEW ORLEANS WEST                Longitude:  90°  8.1' W ( -90.13547)


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


                         BENCH MARK STAMPING:  DISTRICT-1
                         DESIGNATION:          DISTRICT 1

MONUMENTATION:           Flange-encased Rod                    VM#:        18020
AGENCY:                  US Army Corps of Engineers (USE)      IDB PID#:  AB2623
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: AB2623
LATITUDE:   29° 56.4' N (  29.94008)          LONGITUDE:  90°  8.1' W ( -90.13478)


The bench mark is a flange-encased rod located 10.505 m (34.465 ft) north of the
chain link fence running along the north side of the USACE property, 70.0 m
(229.7 ft) SW of the NW corner of house number 404 on Fern Street, 18.2 m (59.7
ft) west of the centerline of the west railroad track running on the west side
of Leake Avenue, 8.0 m (26.2 ft) WNW of power pole number TC817, and 0.5 m (1.6
ft) east of a carsonite witness post.  The datum point is set 5 cm (0.16 ft)
below the ground, being the top of a stainless rod driven to an unknown depth
and enclosed in a 5-inch PVC pipe with NGS logo cap.



                         BENCH MARK STAMPING:  1955 A 2009
                         DESIGNATION:          876 1955 A

MONUMENTATION:           Tidal Station disk                    VM#:        19134
AGENCY:                  National Ocean Survey/Service (NOS)   IDB PID:         
SETTING CLASSIFICATION:  Concrete Pavement                     OPUS PID:        
LATITUDE:   29° 56.0' N (  29.93289)          LONGITUDE:  90°  8.1' W ( -90.13517)


The benchmark is a disk set flush and drilled into the concrete in the NE corner
of the maintenance pier, 42.4 m (139.1 ft) SW of the SW corner of building
number 788, 31.4 m (103.0 ft) east of the tide gage, 7.1 m (23.3 ft) south of
the SW corner of the 4.5 m x 3.5 m (14.8 ft x 11.5 ft) chain link fence
enclosing a generator, and 0.67 m (2.20 ft) NE of the NE corner of building
number 0000005/restrooms.

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

                                                                                
Station ID: 8761955                         PUBLICATION DATE:  12/20/2011
Name:       CARROLLTON, MISSISSIPPI RIVER                     
            LA
NOAA Chart: 11368                           Latitude:   29° 56.0' N (  29.93289)
USGS Quad:  NEW ORLEANS WEST                Longitude:  90°  8.1' W ( -90.13547)


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


                         BENCH MARK STAMPING:  1955 B 2009
                         DESIGNATION:          876 1955 B

MONUMENTATION:           Tidal Station disk                    VM#:        19135
AGENCY:                  National Ocean Survey/Service (NOS)   IDB PID:         
SETTING CLASSIFICATION:  Concrete Slab                         OPUS PID#: BBFX13
LATITUDE:   29° 56.0' N (  29.93364)          LONGITUDE:  90°  8.1' W ( -90.13469)


The benchmark is a disk set flush and drilled in the concrete slab at the south
side of the daycare property, 46.1 m (151.2 ft) NE of the NW corner of the USACE
building number 788, 41.5 m (136.2 ft) north of the north face of the USACE
building number 748/motorpool, 29.0 m (95.1 ft) WNW of the NW corner of the 2.9
m x 5.1 m (9.5 ft x 16.7 ft) electrical utility building, and 22.2 m (72.8 ft)
SW of the wrought iron fence surrounding the daycare center.



                         BENCH MARK STAMPING:  1955 C 2009
                         DESIGNATION:          876 1955 C

MONUMENTATION:           Flange-encased Rod                    VM#:        19136
AGENCY:                  National Ocean Survey/Service (NOS)   IDB PID:         
SETTING CLASSIFICATION:                                        OPUS PID#: BBFX14
LATITUDE:   29° 56.1' N (  29.93447)          LONGITUDE:  90°  8.0' W ( -90.13386)


The benchmark is a flange-encased rod located 17.6 m (57.7 ft) NNW of the north
face of the USACE monument at the south entrance to the USACE property, 7.3 m
(24.0 ft) west of the centerline of the west railroad track running outside the
east side of the USACE property, 3.3 m (10.8 ft) east of the chain link fence
running along the east side of the USACE property, 2.0 m (6.6 ft) south of the
power pole (TE887) located at the south entrance to the USACE property, and 1.6
m (5.25 ft) south of a carsonite witness post.  The datum point is set 4 cm
(0.13 ft) below the ground, being the top of a stainless steel rod driven 21.9 m
(71.9 ft) to refusal, in a sleeve extending 1.0 m (3.28 ft), and encased in a
5-inch PVC pipe with NGS logo cap.

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

                                                                                
Station ID: 8761955                         PUBLICATION DATE:  12/20/2011
Name:       CARROLLTON, MISSISSIPPI RIVER                     
            LA
NOAA Chart: 11368                           Latitude:   29° 56.0' N (  29.93289)
USGS Quad:  NEW ORLEANS WEST                Longitude:  90°  8.1' W ( -90.13547)


                            T I D A L   D A T U M S 


Tidal datums at CARROLLTON, MISSISSIPPI RIVER based on:

     LENGTH OF SERIES:      31 MONTHS
     TIME PERIOD:           March 2009 - September 2011
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:   


Elevations of tidal datums referred to Mean Sea Level (MSL), in METERS:

     HIGHEST OBSERVED WATER LEVEL (05/17/2011)         =  2.412
     MEAN SEA LEVEL                             MSL    =  0.000
     LOWEST  OBSERVED WATER LEVEL (11/07/2010)         = -2.386

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                                MSL

     DISTRICT 1 A                                         0.739
     DISTRICT-1                                           1.063
     1955 A 2009                                          3.254
     1955 B 2009                                          3.766
     1955 C 2009                                          0.794


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

                                                                                
Station ID: 8761955                         PUBLICATION DATE:  12/20/2011
Name:       CARROLLTON, MISSISSIPPI RIVER                     
            LA
NOAA Chart: 11368                           Latitude:   29° 56.0' N (  29.93289)
USGS Quad:  NEW ORLEANS WEST                Longitude:  90°  8.1' W ( -90.13547)


                             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.