U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 09/17/1985
Station ID: 8726159 SUPERCEDED DATE: 04/21/2003
Name: WHITFIELD ESTATES, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 24.5' N
USGS Quad: BRADENTON Longitude: 82° 34.8' W
To reach the tidal bench marks from the intersection of US Highway 41 and
Whitfield Avenue proceed 0.3 mile (0.5 km) west on Whitfield Avenue to
Westmoreland Drive, proceed 0.3 mile (0.5 km) north on Westmoreland Drive to
North Isles Drive, then proceed 0.1 mile (0.2 km) west on North Isles Drive to
its end. The bench marks are located along the seawall, and along Westmoreland
Drive and North Isles Drive. The tide gage and staff were located on a
privately owned pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6159 A 1977
MONUMENTATION: Survey Disk VM#: 6134
AGENCY: PID#: AG7691
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set flush in a concrete seawall, 54.0 feet (16.5 m) SW of the
centerline of North Isles Drive, 43.5 feet (13.3 m) NW of the NW corner of a
swimming pool, 25.8 feet (7.9 m) east of the west end of the seawall, and 3.0
feet (0.9 m) west of the east edge of the south seawall.
BENCH MARK STAMPING: 6159 B 1977
MONUMENTATION: Survey Disk VM#: 6135
AGENCY: PID#: AG7692
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set in a concrete seawall, 50 feet (15 m) north of Bench Mark
6159 A 1977, 34 feet (10 m) NW of the centerline of North Isles Drive, 29 feet
(9 m) east of the west end of the north seawall, and 0.7 foot (0.2 m) west of
the east edge of the north seawall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 09/17/1985
Station ID: 8726159 SUPERCEDED DATE: 04/21/2003
Name: WHITFIELD ESTATES, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 24.5' N
USGS Quad: BRADENTON Longitude: 82° 34.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6159 C 1977
MONUMENTATION: Survey Disk VM#: 6136
AGENCY: PID#: AG7693
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set in a concrete seawall, 120 feet (37 m) NW of the
centerline of North Isles Drive, 96 feet (29 m) north of Bench Mark 6159 B 1977,
and 0.5 foot (0.2 m) west of the east edge of the seawall.
BENCH MARK STAMPING: 6159 E 1977
MONUMENTATION: Survey Disk VM#: 6137
AGENCY: PID#: AG7689
SETTING CLASSIFICATION: Concrete Post
The bench mark is set in a concrete post along Westmoreland Drive, 38.2 feet
(11.6 m) SW of the SW corner of a white block house #8158, 30.0 feet (9.1 m)
east of the centerline of Westmoreland Drive, and 1.7 feet (0.5 m) west of a
utility pole. The bench mark is 0.4 foot (0.1 m) below ground.
BENCH MARK STAMPING: 6159 F 1977
MONUMENTATION: Survey Disk VM#: 6138
AGENCY: PID#: AG7690
SETTING CLASSIFICATION: Rod Mark
The bench mark is 140 feet (43 m) east of Bench Mark 6159 B 1977, 24.5 feet (7.5
m) north of the centerline of North Isles Drive, 6.2 feet (1.9 m) SW of a large
clump of trees with shaggy bark, and 0.9 foot (0.3 m) west of utility pole #106.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 09/17/1985
Station ID: 8726159 SUPERCEDED DATE: 04/21/2003
Name: WHITFIELD ESTATES, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 24.5' N
USGS Quad: BRADENTON Longitude: 82° 34.8' W
T I D A L D A T U M S
Tidal datums at WHITFIELD ESTATES, SARASOTA BAY based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: JUNE-SEPTEMBER 1977
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8725943 BLACKBURN POINT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (06/03/1977) = 3.43
MEAN HIGHER HIGH WATER (MHHW) = 2.17
MEAN HIGH WATER (MHW) = 1.87
MEAN TIDE LEVEL (MTL) = 1.15
MEAN LOW WATER (MLW) = 0.43
MEAN LOWER LOW WATER (MLLW) = 0.00
LOWEST OBSERVED WATER LEVEL (07/01/1977) = -0.45
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
6159 A 1977 5.53 3.66
6159 B 1977 5.63 3.76
6159 C 1977 5.58 3.71
6159 E 1977 5.79 3.92
6159 F 1977 6.28 4.41
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 09/17/1985
Station ID: 8726159 SUPERCEDED DATE: 04/21/2003
Name: WHITFIELD ESTATES, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 24.5' N
USGS Quad: BRADENTON Longitude: 82° 34.8' 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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.