Bench Mark Sheet for 8761993, TCHEFUNCTA RIVER, LAKE PONT LA

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

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

                                                                                
Station ID: 8761993                         PUBLICATION DATE:  11/09/2011
Name:       TCHEFUNCTA RIVER, LAKE PONT                       
            LA
NOAA Chart: 11369                           Latitude:   30° 22.7' N (  30.37830)
USGS Quad:  MADISONVILLE                    Longitude:  90°  9.6' W ( -90.16000)


To reach the tidal bench marks from the intersection of State Highways 1077 and
22 in Madisonville, proceed south on State Highway 1077 for 3.4 km (2.1 mi) to
the Town of Madisonville Recreation Area.  The bench marks are in the vicinity
of the recreation area and north along State Highway 1077.  The tide gage and
staff were located at the NE end of the northernmost dock of the covered boat
house at the recreation area.


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


                 PRIMARY BENCH MARK STAMPING:  1993 A 1982
                         DESIGNATION:          876 1993 A

MONUMENTATION:           Tidal Station disk                    VM#:        10864
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30° 22.7' N (  30.37830)          LONGITUDE:  90°  9.6' W ( -90.16000)


The primary bench mark is a disk located on the south side of the parking lot
across the road from the boat house at the Town of Madisonville Recreation Area,
112 m (366 ft) ENE of bench mark WES 14 1978, 18 m (60 ft) NW of the wood
seawall, 3 m (9 ft) west of a utility pole, and 2 m (8 ft) NW of a fence line. 
The bench mark is set 0.12 m (0.4 ft) below ground level, 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 pipe and concrete kickblock.

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

                                                                                
Station ID: 8761993                         PUBLICATION DATE:  11/09/2011
Name:       TCHEFUNCTA RIVER, LAKE PONT                       
            LA
NOAA Chart: 11369                           Latitude:   30° 22.7' N (  30.37830)
USGS Quad:  MADISONVILLE                    Longitude:  90°  9.6' W ( -90.16000)


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


                         BENCH MARK STAMPING:  1993 B 1982
                         DESIGNATION:          876 1993 B

MONUMENTATION:           Tidal Station disk                    VM#:        10865
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30° 22.7' N (  30.37830)          LONGITUDE:  90°  9.6' W ( -90.16000)


The bench mark is a disk located north of the recreation area, 43 m (141 ft)
north of the NW corner of the boat ramp, 24 m (80 ft) NNE of a utility pole, 15
m (50 ft) WNW of the west shoreline of Tchefuncta River, and 7 m (24 ft) WNW of
the centerline of State Highway 1077.  The bench mark is set 9 cm (0.3 ft) below
ground level, 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 pipe and concrete
kickblock.



                         BENCH MARK STAMPING:  1993 C 1982
                         DESIGNATION:          876 1993 C

MONUMENTATION:           Tidal Station disk                    VM#:        10866
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30° 22.7' N (  30.37830)          LONGITUDE:  90°  9.6' W ( -90.16000)


The bench mark is a disk located on the west side of the parking lot at the
recreation area, 106 m (348 ft) WNW of the centerline of State Highway 1077, 95
m (312 ft) NW of bench mark 1993 A 1982, and 2 m (6 ft) NNE of the NE corner of
the boat ramp parking lot fence.  The bench mark is set 9 cm (0.3 ft) below
ground level, 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 pipe and concrete
kickblock.

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

                                                                                
Station ID: 8761993                         PUBLICATION DATE:  11/09/2011
Name:       TCHEFUNCTA RIVER, LAKE PONT                       
            LA
NOAA Chart: 11369                           Latitude:   30° 22.7' N (  30.37830)
USGS Quad:  MADISONVILLE                    Longitude:  90°  9.6' W ( -90.16000)


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


                         BENCH MARK STAMPING:  1993 D 1982
                         DESIGNATION:          876 1993 D

MONUMENTATION:           Tidal Station disk                    VM#:        10867
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30° 22.7' N (  30.37830)          LONGITUDE:  90°  9.6' W ( -90.16000)


The bench mark is a disk located north of the recreation area, 66 m (218 ft) NNE
of bench mark 1993 B 1982, 65 m (213 ft) SSW of the third utility pole north of
the boat dock, 30 m (97 ft) NNW of the second utility pole north of the boat
dock, 15 m (50 ft) WNW of the west shoreline of Tchefuncta River, and 5 m (18
ft) WNW of the centerline of State Highway 1077.  The bench mark is set 9 cm
(0.3 ft) below ground level, 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 pipe and
concrete kickblock.



                         BENCH MARK STAMPING:  WES 14A 1978
                         DESIGNATION:          876 1993 WES 14A

MONUMENTATION:           Survey disk                           VM#:        10868
AGENCY:                  US Army Corps of Engineers (USE)      IDB PID#:        
SETTING CLASSIFICATION:  Copper-clad steel rod                 OPUS PID:        
LATITUDE:   30° 22.7' N (  30.37830)          LONGITUDE:  90°  9.6' W ( -90.16000)


The bench mark is a disk located at the south end of State Road 1077, west of
bench mark 1993 A 1982, 22 m (71 ft) north of the NW corner piling of a pole
house, 7 m (22 ft) north of the centerline of the road, 3.87 m (12.7 ft) SSE of
a utility pole with transformer, and 0.61 m (2.0 ft) south of a fence post with
witness sign.  The bench mark is crimped to the top of a copper-clad steel rod
driven to unknown depth,  and encased in a 6-inch PVC pipe.

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

                                                                                
Station ID: 8761993                         PUBLICATION DATE:  11/09/2011
Name:       TCHEFUNCTA RIVER, LAKE PONT                       
            LA
NOAA Chart: 11369                           Latitude:   30° 22.7' N (  30.37830)
USGS Quad:  MADISONVILLE                    Longitude:  90°  9.6' W ( -90.16000)


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


                         BENCH MARK STAMPING:  52 V 011 1977
                         DESIGNATION:          52 V 011 LADTD

MONUMENTATION:           Survey disk                           VM#:        10869
AGENCY:                  Lousiana Department of Transportation 
                         (LADTD)                               IDB PID#:  BJ2852
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 24.2' N (  30.40330)          LONGITUDE:  90°  9.4' W ( -90.15670)


The bench mark is a disk set in a concrete monument in the village of
Madisonville, one block east along State Highway 22 from the junction of
Highways 21 and 22, 53 m (174 ft) south of the centerline of State Highway 22,
19 m (62 ft) NE of a flag pole at the Madisonville Town Hall, 9 m (29 ft) west
of the centerline of Water Street, and 0.3 m (1 ft) west of a witness post.



                         BENCH MARK STAMPING:  52 V 012 1977
                         DESIGNATION:          52 V 012 LADTD

MONUMENTATION:           Survey disk                           VM#:        10870
AGENCY:                  Lousiana Department of Transportation 
                         (LADTD)                               IDB PID#:  BJ2853
SETTING CLASSIFICATION:  Concrete monument                     OPUS PID:        
LATITUDE:   30° 24.9' N (  30.41500)          LONGITUDE:  90°  9.8' W ( -90.16330)


The bench mark is a disk set in a concrete monument, 1.4 km (0.9 mi) north along
State Highway 21 from the junction of Highways 21 and 22 in Madisonville, 23 m
(77 ft) west of the centerline of State Highway 21, 8 m (26 ft) SW of a 2 m (6
ft) diameter live oak tree in the Theodore Dendinger Memorial Cemetery, and 7 m
(24 ft) NW of a 2 m (5 ft) diameter live oak tree.

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

                                                                                
Station ID: 8761993                         PUBLICATION DATE:  11/09/2011
Name:       TCHEFUNCTA RIVER, LAKE PONT                       
            LA
NOAA Chart: 11369                           Latitude:   30° 22.7' N (  30.37830)
USGS Quad:  MADISONVILLE                    Longitude:  90°  9.6' W ( -90.16000)


                            T I D A L   D A T U M S 


Tidal datums at TCHEFUNCTA RIVER, LAKE PONT based on:

     LENGTH OF SERIES:      5 YEARS
     TIME PERIOD:           June 1983 - May 1988
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8761927 USCG NEW CANAL STA., LAKE PONTCHARTRAIN


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

     HIGHEST OBSERVED WATER LEVEL (01/21/1983)         =  1.014
     MEAN HIGHER HIGH WATER                     MHHW   =  0.173
     MEAN HIGH WATER                            MHW    =  0.172
     MEAN SEA LEVEL                             MSL    =  0.088
     MEAN TIDE LEVEL                            MTL    =  0.084
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     MEAN LOW WATER                             MLW    = -0.004
     LOWEST  OBSERVED WATER LEVEL (04/12/1988)         = -0.809

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     1993 A 1982                                 0.297    0.125
     1993 B 1982                                 0.310    0.138
     1993 C 1982                                 0.219    0.047
     1993 D 1982                                 0.159   -0.013
     WES 14A 1978                                0.523    0.351
     52 V 011 1977                               1.528    1.356
     52 V 012 1977                               3.309    3.137


Foot Notes:

Bench marks 52 V 011 1977 and 52 V 012 1977 are based on one differential
leveling connection and do not meet the quality control standards of the NOS. 
Therefore, caution should be used when deriving elevations for these marks.

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

                                                                                
Station ID: 8761993                         PUBLICATION DATE:  11/09/2011
Name:       TCHEFUNCTA RIVER, LAKE PONT                       
            LA
NOAA Chart: 11369                           Latitude:   30° 22.7' N (  30.37830)
USGS Quad:  MADISONVILLE                    Longitude:  90°  9.6' W ( -90.16000)


                             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.

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