U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 12/21/1983
Station ID: 8726238 SUPERCEDED DATE: 04/21/2003
Name: BRADEN POINT, BRADEN RIVER
FLORIDA
NOAA Chart: 11414 Latitude: 27° 29.2' N
USGS Quad: BRADENTON Longitude: 82° 30.3' W
To reach the tidal bench marks from the intersection of state route 64 east and
Morgan Johnson Road, travel south on Morgan Johnson Road 2.2 miles (3.5 km) to
the intersection of 41st Avenue east and Morgan Johnson Road, and West on 41st
Avenue east for 0.2 miles (0.3 km) to the end of the road. The tide gage and
staff were along the seawall, and the bench marks are along the seawall and 41st
Avenue east.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6238 A 1977
MONUMENTATION: Survey Disk VM#: 6162
AGENCY: PID#: AG7707
SETTING CLASSIFICATION: Surface
The bench mark is 53.5 feet (16.3 m) west of the NW corner of house #5507 on
41st Avenue east.
BENCH MARK STAMPING: 6238 B 1977
MONUMENTATION: Survey Disk VM#: 6163
AGENCY: PID#: AG7708
SETTING CLASSIFICATION: Seawall
The bench mark is set flush in a seawall, 139.0 feet (42.4 m) south of Bench
Mark 6238 A 1977, and 20.0 feet (6.1 m) north of a curve in the seawall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 12/21/1983
Station ID: 8726238 SUPERCEDED DATE: 04/21/2003
Name: BRADEN POINT, BRADEN RIVER
FLORIDA
NOAA Chart: 11414 Latitude: 27° 29.2' N
USGS Quad: BRADENTON Longitude: 82° 30.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6238 C 1977
MONUMENTATION: Survey Disk VM#: 6164
AGENCY: PID#: AG7706
SETTING CLASSIFICATION: Post
The bench mark is set on a post 116.0 feet (35.4 m) east of Bench Mark 6238 B
1977, 7.0 feet (2.1 m) west of the edge of the road, 2.6 feet (0.8 m) south of a
drain, and 1.0 foot (0.3 m) east of a power pole.
BENCH MARK STAMPING: 6238 E 1977
MONUMENTATION: Survey Disk VM#: 6165
AGENCY: PID#: AG7705
SETTING CLASSIFICATION: Post
The bench mark is set on a post mark 350.0 feet (106.7 m) east of Bench Mark
6238 C 1977, 23.0 feet (7.0 m) feet north of the centerline of 41st Avenue east,
and 1.4 feet (0.4 m) north of a power pole.
BENCH MARK STAMPING: 6238 F 1977
MONUMENTATION: Survey Disk VM#: 6166
AGENCY: PID#: AG7704
SETTING CLASSIFICATION: Concrete Drain Support
The bench mark is set in the SE corner of a concrete drain support, 91.7 feet
(28.0 m) east of Bench Mark 6238 E 1977, and 20.0 feet (6.1 m) north of the
centerline of 41st Avenue east.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 12/21/1983
Station ID: 8726238 SUPERCEDED DATE: 04/21/2003
Name: BRADEN POINT, BRADEN RIVER
FLORIDA
NOAA Chart: 11414 Latitude: 27° 29.2' N
USGS Quad: BRADENTON Longitude: 82° 30.3' W
T I D A L D A T U M S
Tidal datums at BRADEN POINT, BRADEN RIVER based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: MAY-AUGUST 1977
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8726247 BRADENTON
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (06/02/1977) = 3.29
MEAN HIGHER HIGH WATER MHHW = 2.19
MEAN HIGH WATER MHW = 1.92
MEAN TIDE LEVEL MTL = 1.09
MEAN LOW WATER MLW = 0.26
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (04/08/1977) = -0.61
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
6238 A 1977 3.87 1.95
6238 B 1977 3.98 2.06
6238 C 1977 4.19 2.27
6238 E 1977 5.03 3.11
6238 F 1977 5.38 3.46
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 12/21/1983
Station ID: 8726238 SUPERCEDED DATE: 04/21/2003
Name: BRADEN POINT, BRADEN RIVER
FLORIDA
NOAA Chart: 11414 Latitude: 27° 29.2' N
USGS Quad: BRADENTON Longitude: 82° 30.3' 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.