U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8726892 PUBLICATION DATE: 02/26/2004
Name: SPRING BAYOU, TARPON SPRINGS
FL
NOAA Chart: 11412 Latitude: 28° 8.8' N ( 28.14670)
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W ( -82.75830)
To reach the tidal bench marks from the intersection of U.S. Highway ALT 19
(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 ALT 19, Tarpon
Avenue, and Spring Boulevard. The gage and staff were located at the bulkhead
and pier in Spring Bayou.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1975
DESIGNATION: 872 6892 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 7633
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7471
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 28° 8.8' N ( 28.14670) LONGITUDE: 82° 45.5' W ( -82.75830)
The primary bench mark is a disk set in the concrete bulkhead near the
intersection of Spring Boulevard and the west end of Tarpon Avenue, on the SE
corner of the concrete pier on Spring Bayou, 14.90 m (48.9 ft) SW of the SW
corner of the stairs leading to the pier from Spring Boulevard, 0.30 m (1.0 ft)
west of the bulkhead face, and 0.21 m (0.7 ft) above the sidewalk surface.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8726892 PUBLICATION DATE: 02/26/2004
Name: SPRING BAYOU, TARPON SPRINGS
FL
NOAA Chart: 11412 Latitude: 28° 8.8' N ( 28.14670)
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W ( -82.75830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1975
DESIGNATION: 872 6892 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 7634
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7470
SETTING CLASSIFICATION: Concrete manhole collar OPUS PID:
LATITUDE: 28° 8.8' N ( 28.14670) LONGITUDE: 82° 45.5' W ( -82.75830)
The bench mark is a disk set in the concrete collar of a manhole at the NE
intersection of Tarpon Avenue and Spring Boulevard, 37.80 m (124.0 ft) NE of
bench mark NO 1 1975, 12.19 m (40.0 ft) east of the centerline of Spring
Boulevard, 4.57 m (15.0 ft) north of the centerline of Tarpon Avenue, 0.30 m
(1.0 ft) NE of the road curb, and 0.18 m (0.6 ft) above the road surface.
BENCH MARK STAMPING: NO 3 1975
DESIGNATION: 872 6892 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 7635
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7469
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 28° 8.8' N ( 28.14670) LONGITUDE: 82° 45.5' W ( -82.75830)
The bench mark is a disk located along the north side of Tarpon Avenue, 77.72 m
(255 ft) east of the centerline of Spring Boulevard, 65.53 m (215.0 ft) east of
bench mark NO 2 1975, 0.70 m (2.3 ft) north of the north curb of Tarpon Avenue,
and 0.30 m (1.0 ft) south of utility pole #12A535. The bench mark is set at
ground level, crimped to the top of a copper-clad steel rod driven an
unspecified depth to refusal, and encased in a PVC pipe and concrete kickblock.
NOTE: Mark not found by US Power Squadron in 1995.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8726892 PUBLICATION DATE: 02/26/2004
Name: SPRING BAYOU, TARPON SPRINGS
FL
NOAA Chart: 11412 Latitude: 28° 8.8' N ( 28.14670)
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W ( -82.75830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: PINCO M
DESIGNATION: PINCO M
MONUMENTATION: Survey disk VM#: 7636
AGENCY: Pinellas County IDB PID#: AL0303
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 28° 8.8' N ( 28.14670) LONGITUDE: 82° 45.4' W ( -82.75670)
The bench mark is a disk set into the top of a concrete monument at the SW
corner of the intersection of U.S. Highway ALT 19 (South Pinellas Avenue) and
Tarpon Avenue (State Road 582), 15.24 m (50.0 ft) south of the south curb of
Tarpon Avenue, 13 m (43 ft) south of a concrete lamp post, 1.07 m (3.5 ft) west
of a 0.21 m (0.7 ft) metal "Sunoco" sign post, and 0.61 m (2.0 ft) west of the
west curb of U.S. Highway ALT 19.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8726892 PUBLICATION DATE: 02/26/2004
Name: SPRING BAYOU, TARPON SPRINGS
FL
NOAA Chart: 11412 Latitude: 28° 8.8' N ( 28.14670)
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W ( -82.75830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Y 147
DESIGNATION: Y 147
ALIAS: 17.585
MONUMENTATION: Survey disk VM#: 7637
AGENCY: Pinellas County IDB PID#: AL6619
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 28° 9.0' N ( 28.15000) LONGITUDE: 82° 45.4' W ( -82.75670)
The bench mark is a disk set into the top of a 9 cm (0.3 ft) diameter round
concrete post at the NW corner of the intersection of Read Street, 0.5 km (0.3
mi) north along North Pinellas Avenue (U.S. Highway ALT 19) from the City Hall
at Tarpon Springs, 13.72 m (45.0 ft) north of the centerline of Read Street,
11.13 m (36.5 ft) SE of the SE corner of a wood frame school building, 6.40 m
(21.0 ft) north of the SE corner of the Greek Orthodox, school yard, 4.57 m
(15.0 ft) west of the centerline of North Pinellas Avenue, 0.15 m (0.5 ft) west
of the west curb of North Pinellas Avenue, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8726892 PUBLICATION DATE: 02/26/2004
Name: SPRING BAYOU, TARPON SPRINGS
FL
NOAA Chart: 11412 Latitude: 28° 8.8' N ( 28.14670)
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W ( -82.75830)
T I D A L D A T U M S
Tidal datums at SPRING BAYOU, TARPON SPRINGS based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: January 1976 - January 1976
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8726924 ANCLOTE RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.929
MEAN HIGH WATER MHW = 0.815
North American Vertical Datum NAVD88 = 0.557
MEAN SEA LEVEL MSL = 0.493
MEAN TIDE LEVEL MTL = 0.484
MEAN LOW WATER MLW = 0.153
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 1 1975 1.648 0.833
NO 2 1975 4.165 3.350
NO 3 1975 5.084 4.269
PINCO M 7.268 6.453
Y 147 5.676 4.861
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8726892 PUBLICATION DATE: 02/26/2004
Name: SPRING BAYOU, TARPON SPRINGS
FL
NOAA Chart: 11412 Latitude: 28° 8.8' N ( 28.14670)
USGS Quad: TARPON SPRINGS Longitude: 82° 45.5' W ( -82.75830)
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.