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Bench Mark Sheet for 8732828, Weeks Bay, Mobile Bay AL

Superseded Epoch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Small blue map location marker Unpublished bench mark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  4

                                                                                
Station ID: 8732828                         PUBLICATION DATE:  01/24/2018
Name:       WEEKS BAY, MOBILE BAY                             
            AL
NOAA Chart: 11376                           Latitude:   30° 25.0' N (  30.41689)
USGS Quad:  MOBILE                          Longitude:  87° 49.5' W ( -87.82539)


From Interstate 10 South in Mobile proceed south on I-10 to Highway 98 South.
Travel south on 98 South for 28 miles to the Weeks Bay Reserve and the Fish
River Bridge, before going over the bridge take a paved road on the left and
follow it until it crosses under the bridge.  Before you go under the bridge
there is a dirt path that turns left, take that path and the station is located
on the left next to the canal.  The bench marks are located along the bridge.


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


                 PRIMARY BENCH MARK STAMPING:  2828 A 2007
                         DESIGNATION:          873 2828 A

MONUMENTATION:           Tidal Station disk                    VM#:        18487
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID#: BBBG65
LATITUDE:   30° 25.0' N (  30.41678)          LONGITUDE:  87° 49.5' W ( -87.82542)


The primary bench mark is a disk located at the Weeks Bay Reserve on the north
side of Highway 98 Bridge over the Fish River 20.11 m (65.98 ft) NE of the
centerline of a paved road leading to the Weeks Bay Boat Ramp, 5.45 m (17.88 ft)
south of the southern corner of the NOAA Tide Station, 1.49 m (4.89 ft) WNW of a
witness post.  The bench mark is set flush with the ground being a deep rod
driven 27.4 m (89.89 ft) to refusal with grease sleeve and an aluminum logo cap
stamped 2828 A 2007.

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

                                                                                
Station ID: 8732828                         PUBLICATION DATE:  01/24/2018
Name:       WEEKS BAY, MOBILE BAY                             
            AL
NOAA Chart: 11376                           Latitude:   30° 25.0' N (  30.41689)
USGS Quad:  MOBILE                          Longitude:  87° 49.5' W ( -87.82539)


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


                         BENCH MARK STAMPING:  2828 B 2007
                         DESIGNATION:          873 2828 B

MONUMENTATION:           Tidal Station disk                    VM#:        18489
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Stainless steel rod                   OPUS PID:        
LATITUDE:   30° 25.1' N (  30.41767)          LONGITUDE:  87° 49.6' W ( -87.82703)


The bench mark is a vertical mark set flush in the fifth bridge support from the
West end of the bridge on the South side, 300.0 ft (91.4 m) South of the wing
wall on the North end of the us 98 bridge, 244.0 ft (74.4 m) North of the center
line of the service road leading into the weeks bay public boat ramp, 39.5 ft
(12.0 m) East of the center line of the north to suth asphalt bike path, 26.6 ft
(8.1 m) West of the center line of the pile bent, 4.3 ft (1.3 m) above ground
under pile bent.



                         BENCH MARK STAMPING:  2828 C 2007
                         DESIGNATION:          873 2828 C

MONUMENTATION:           Survey disk                           VM#:        18490
AGENCY:                  National Ocean Service (NOS)          IDB PID#:        
SETTING CLASSIFICATION:  Concrete wingwall                     OPUS PID:        
LATITUDE:   30° 25.0' N (  30.41739)          LONGITUDE:  87° 49.6' W ( -87.82686)


The bench mark is a disk set flush with the concrete wingwall, located at the
Highway 98 Bridge over the Fish River on the SW end of the bridge, 44.79 m
(146.95 ft) SE of mile marker 56, 11.55 m (37.89 ft) NE of the old Highway 98
roadway, 7.14 m (23.43 ft) south of the centerline of Highway 98 Bridge, and
0.54 m (1.77 ft) above ground.

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

                                                                                
Station ID: 8732828                         PUBLICATION DATE:  01/24/2018
Name:       WEEKS BAY, MOBILE BAY                             
            AL
NOAA Chart: 11376                           Latitude:   30° 25.0' N (  30.41689)
USGS Quad:  MOBILE                          Longitude:  87° 49.5' W ( -87.82539)


                            T I D A L   D A T U M S 


Tidal datums at WEEKS BAY, MOBILE BAY based on:

     LENGTH OF SERIES:      6 YEARS
     TIME PERIOD:           3/08-2/12, 1/14-12/14, 5/15-4/16
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8729840 PENSACOLA, PENSACOLA BAY


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

     HIGHEST OBSERVED WATER LEVEL (10/08/2017)         =  1.765
     MEAN HIGHER HIGH WATER                     MHHW   =  0.490
     MEAN HIGH WATER                            MHW    =  0.455
     MEAN TIDE LEVEL                            MTL    =  0.245
     MEAN SEA LEVEL                             MSL    =  0.243
     MEAN LOW WATER                             MLW    =  0.034
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (02/05/2009)         = -0.556

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     2828 A 2007                                 0.786    0.331
     2828 B 2007                                 2.769    2.314
     2828 C 2007                                 3.509    3.054


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

                                                                                
Station ID: 8732828                         PUBLICATION DATE:  01/24/2018
Name:       WEEKS BAY, MOBILE BAY                             
            AL
NOAA Chart: 11376                           Latitude:   30° 25.0' N (  30.41689)
USGS Quad:  MOBILE                          Longitude:  87° 49.5' W ( -87.82539)


                             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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Products available at 8732828 Weeks Bay, Mobile Bay, AL

Revised: 10/15/2013
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services