U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8720143 PUBLICATION DATE: 02/05/2004
Name: SAWPIT CREEK
FL
NOAA Chart: 11488 Latitude: 30° 30.2' N ( 30.50330)
USGS Quad: AMELIA CITY Longitude: 81° 28.3' W ( -81.47170)
To reach the tidal bench marks from the intersection of State Road 105
(Heckscher Drive) and New Berlin Road in North Jacksonville, proceed north along
New Berlin Road for 5.8 km (3.6 mi) to Cedar Point Road, then turn right and
proceed east on Cedar Point Road for 9.2 km (5.7 mi) to Sawpit Road, the turn
left and proceed north on Sawpit Road for 5.1 km (3.2 mi) to a dirt driveway
leading to the residence of J.T. Murphy. The bench marks are located along
Sawpit Road and along the dirt driveway. The tide gage and staff were located
on the inside of J.T. Murphys L shaped dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0143 D 1978
DESIGNATION: 872 0143 D
MONUMENTATION: Tidal Station disk VM#: 5041
AGENCY: National Ocean Survey (NOS) IDB PID#: BC1378
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 30° 30.2' N ( 30.50330) LONGITUDE: 81° 28.4' W ( -81.47333)
The primary bench mark is a disk about 94 m (310 ft) north of bench mark SAWPIT
NO 2 1934, 25 m (83 ft) west of the SW corner of a wooden shed, 14 m (46 ft)
west of the centerline of the dirt driveway, 9 m (30 ft) west of a large group
of cedar trees, and 0.30 m (1.0 ft) east of a witness post. The bench mark is
set about level with the ground, crimped to the top of a copper-clad steel rod
driven 13.4 m (44 ft) to refusal, and encased in a pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8720143 PUBLICATION DATE: 02/05/2004
Name: SAWPIT CREEK
FL
NOAA Chart: 11488 Latitude: 30° 30.2' N ( 30.50330)
USGS Quad: AMELIA CITY Longitude: 81° 28.3' W ( -81.47170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: SAWPIT NO 2 1934
DESIGNATION: 872 0143 TIDAL SAWPIT 2
MONUMENTATION: Bench Mark disk VM#: 5039
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: BC1375
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 30.2' N ( 30.50330) LONGITUDE: 81° 28.4' W ( -81.47333)
The bench mark is a disk set in the top of an 8-inch diameter tile pipe filled
with concrete, 26 m (85 ft) SE of the centerline of the dirt driveway, 15.97 m
(52.4 ft) south of bench mark SAWPIT NO 3 1934, and 5 m (15 ft) SW of a clump of
oak trees with painted blazed triangle cut into the largest tree.
BENCH MARK STAMPING: SAWPIT NO 3 1934
DESIGNATION: 872 0143 TIDAL SAWPIT 3
MONUMENTATION: Bench Mark disk VM#: 5040
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: BC1374
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 30.2' N ( 30.50330) LONGITUDE: 81° 28.3' W ( -81.47170)
The bench mark is a disk set in the top of an 8-inch diameter tile pipe filled
with concrete, 24 m (78 ft) east of the centerline of the dirt driveway, and 1 m
(2 ft) SE of an oak tree with an orange blazed triangle cut into the tree.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8720143 PUBLICATION DATE: 02/05/2004
Name: SAWPIT CREEK
FL
NOAA Chart: 11488 Latitude: 30° 30.2' N ( 30.50330)
USGS Quad: AMELIA CITY Longitude: 81° 28.3' W ( -81.47170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0143 E 1978
DESIGNATION: 872 0143 E
MONUMENTATION: Tidal Station disk VM#: 5042
AGENCY: National Ocean Survey (NOS) IDB PID#: BC1376
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 30.1' N ( 30.50167) LONGITUDE: 81° 28.4' W ( -81.47333)
The bench mark is disk set in the top of a concrete monument at the junction of
Sawpit Road and the dirt driveway, 23 m (77 ft) south of the intersection of
Sawpit Road and the dirt driveway, 8 m (25 ft) west of the centerline of Sawpit
Road, 0.3 m (1 ft) east of a witness post, and 0.3 m (1 ft) above road level.
BENCH MARK STAMPING: 0143 F 1978
DESIGNATION: 872 0143 F
MONUMENTATION: Tidal Station disk VM#: 5043
AGENCY: National Ocean Survey (NOS) IDB PID#: BC1377
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 30° 30.2' N ( 30.50330) LONGITUDE: 81° 28.3' W ( -81.47170)
The bench mark is a disk located along Sawpit Road about 0.5 km (0.3 mi) south
of the junction of Sawpit Road and the dirt driveway, 12 m (38 ft) east of the
centerline of Sawpit Road, 4 m (12 ft) NW of a telephone pole, and 0.3 m (1 ft)
west of a witness post. The bench mark is set about level with the road,
crimped to the top of a copper-clad steel rod driven 6.1 m (20 ft) and encased
in a pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8720143 PUBLICATION DATE: 02/05/2004
Name: SAWPIT CREEK
FL
NOAA Chart: 11488 Latitude: 30° 30.2' N ( 30.50330)
USGS Quad: AMELIA CITY Longitude: 81° 28.3' W ( -81.47170)
T I D A L D A T U M S
Tidal datums at SAWPIT CREEK based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: July 1978 - July 1978
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8720098 NASSAUVILLE, NASSAU RIVER EAST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.696
MEAN HIGH WATER MHW = 1.592
MEAN SEA LEVEL MSL = 0.828
MEAN TIDE LEVEL MTL = 0.818
MEAN LOW WATER MLW = 0.044
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
0143 D 1978 3.490 1.898
SAWPIT NO 2 1934 3.907 2.315
SAWPIT NO 3 1934 3.860 2.268
0143 E 1978 3.910 2.318
0143 F 1978 4.021 2.429
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8720143 PUBLICATION DATE: 02/05/2004
Name: SAWPIT CREEK
FL
NOAA Chart: 11488 Latitude: 30° 30.2' N ( 30.50330)
USGS Quad: AMELIA CITY Longitude: 81° 28.3' W ( -81.47170)
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.