U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 09/10/1984
Station ID: 8726892 SUPERCEDED DATE: 04/21/2003
Name: SPRING BAYOU, NORTH EAST WHITCOMB BAYOU
FLORIDA
NOAA Chart: 11412 Latitude: 28° 8.8' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W
To reach the tidal bench marks from the intersection of U.S. Highway 19 (ALT)
(South Pinellas Avenue) and Tarpon Avenue (State Route 582) in Tarpon Springs,
proceed west on Tarpon Avenue to its end and the intersection with Spring
Boulevard. The bench marks are in the near area and along U.S. Highway 19
(ALT), Tarpon Avenue, and Spring Boulevard, and the gage and staff were located
at the bulkhead and pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1975
MONUMENTATION: Survey Disk VM#: 7633
AGENCY: PID#: AL7471
SETTING CLASSIFICATION: Concrete Bulkhead
The bench mark is in the city of Tarpon Springs, at the intersection of Spring
Boulevard and the west end of Tarpon Avenue, on the SE corner of the concrete
pier on Spring Bayou, 49.0 feet (14.9 m) SW of the SW corner of the stairs
leading to the pier from Spring Boulevard and 1.0 foot (0.3 m) west of the
bulkhead face, and is set flush into the concrete 0.7 foot (0.2 m) above the
sidewalk surface.
BENCH MARK STAMPING: NO 2 1975
MONUMENTATION: Survey Disk VM#: 7634
AGENCY: PID#: AL7470
SETTING CLASSIFICATION: Concrete Man Hole Collar
The bench mark is set into the concrete collar of a man hole, 0.6 (0.2 m) above
road surface, and is at the NE corner of the intersection of Tarpon Avenue and
Spring Boulevard, 124.0 feet (37.8 m) NE of Bench Mark NO 1 1975 and 1.0 foot
(0.3 m) NE of the road curb.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 09/10/1984
Station ID: 8726892 SUPERCEDED DATE: 04/21/2003
Name: SPRING BAYOU, NORTH EAST WHITCOMB BAYOU
FLORIDA
NOAA Chart: 11412 Latitude: 28° 8.8' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1975
MONUMENTATION: Survey Disk VM#: 7635
AGENCY: PID#: AL7469
SETTING CLASSIFICATION: Copper-Coated Steel Rod
The bench mark is 215.0 feet (65.5 m) east of Bench Mark NO 2 1975, 2.3 feet
(0.7 m) north of the north curb of Tarpon Avenue and 1.0 foot (0.3 m) south of
utility pole NO 12 A 535. The bench mark is crimped to a 5/8-inch diameter
copper-coated steel rod driven to refusal and encased in a 0.3 foot (0.1 m)
diameter PVC protector pipe with concrete, at ground level.
BENCH MARK STAMPING: PINCO M
MONUMENTATION: Survey Disk VM#: 7636
AGENCY: PID#: AL0303
SETTING CLASSIFICATION: Concrete Post
The bench mark is set into the top of a concrete post, at ground level, and is
in the SW corner of the intersection of U.S. Highway 19 (ALT) (S. Pinellas
Avenue) and Tarpon Avenue (State Route 582), 50.0 feet (15.2 m) south of the
south curb of SR 582, 43.0 feet (13.1 m) south of a concrete lamp post, 3.5 feet
(1.1 m) west of an 8-inch metal Sunoco sign and 2.0 feet (0.6 m) west of the
west curb of U.S. Highway 19 (ALT).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 09/10/1984
Station ID: 8726892 SUPERCEDED DATE: 04/21/2003
Name: SPRING BAYOU, NORTH EAST WHITCOMB BAYOU
FLORIDA
NOAA Chart: 11412 Latitude: 28° 8.8' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Y 147
MONUMENTATION: Survey Disk VM#: 7637
AGENCY: PID#: AL6619
SETTING CLASSIFICATION: Concrete Post
The bench mark is set into the top of a 0.3 foot (0.1 m) diameter concrete post,
at ground level, and 0.3 mile (0.5 m) north along North Pinellas Avenue (U.S.
Highway 19 ALT) from the City Hall at Tarpon Springs, at the NW corner of the
intersection with Read Street, 45.0 feet (13.7 m) north of the centerline of
Read Street, 36.5 feet (11.1 m) SE of the SE corner of a wood frame school
building, 21.0 feet (6.4 m) north of the SE corner of the Greek Orthodox, school
yard, 15.0 feet(4.6 m) west of the centerline of North Pinellas Avenue and 0.5
foot (0.2 m) west of the west curb of North Pinellas Avenue.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 09/10/1984
Station ID: 8726892 SUPERCEDED DATE: 04/21/2003
Name: SPRING BAYOU, NORTH EAST WHITCOMB BAYOU
FLORIDA
NOAA Chart: 11412 Latitude: 28° 8.8' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W
T I D A L D A T U M S
Tidal datums at SPRING BAYOU, NORTH EAST WHITCOMB BAYOU based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: JANUARY 1976
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8726924 ANCLOTE, ANCLOTE RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (12/25/1975) = 4.20
MEAN HIGHER HIGH WATER MHHW = 3.10
MEAN HIGH WATER MHW = 2.71
MEAN TIDE LEVEL MTL = 1.61
MEAN LOW WATER MLW = 0.51
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (01/19/1976) = -1.54
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 1 1975 5.59 2.88
NO 2 1975 13.85 11.14
NO 3 1975 16.86 14.15
PINCO M 24.03 21.32
Y 147 18.81 16.10
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 09/10/1984
Station ID: 8726892 SUPERCEDED DATE: 04/21/2003
Name: SPRING BAYOU, NORTH EAST WHITCOMB BAYOU
FLORIDA
NOAA Chart: 11412 Latitude: 28° 8.8' N
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' 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.