U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9415021 PUBLICATION DATE: 09/28/2016
Name: BLACKSLOUGH LANDING, SAN JOAQUIN RIVER
CA
NOAA Chart: 18661 Latitude: 37° 59.7' N ( 37.99469)
USGS Quad: HOLT Longitude: 121° 25.1' W (-121.41904)
To reach the tidal bench marks from the junction of State Highway 4 and
Interstate 5 in Crockett, proceed west on Highway 4 for 14 km (9 mi), then turn
right and proceed north on Holt Road until the road dead ends at a T junction
with Neugebauer Road. The bench marks are to the south of and along Neugebauer
Road. The tide gage and staff were located on the peat loading dock north of a
garage and mobile house. To reach the tide station proceed west from Stockton
along Highway 4 from the junction of Highway 4 and Interstate 5, proceed 8.85km
(5.5 mi) then turn right and proceed north on S. Island dr., proceed 4.8km (3.0
mi), turn right and proceed north on S. Holt rd., continue until the road dead
ends at a T junction with Windmill Cove rd. Turn right on Windmill Cove rd. and
proceed 0.18 km (0.11 mi). The tide station is 170 ft NE of gate located on the
north side of Windmill Cove rd.
T I D A L B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9415021 PUBLICATION DATE: 09/28/2016
Name: BLACKSLOUGH LANDING, SAN JOAQUIN RIVER
CA
NOAA Chart: 18661 Latitude: 37° 59.7' N ( 37.99469)
USGS Quad: HOLT Longitude: 121° 25.1' W (-121.41904)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 3 1933
DESIGNATION: POLE=TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 8504
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: HS0359
SETTING CLASSIFICATION: Concrete base OPUS PID:
LATITUDE: 37° 59.6' N ( 37.99403) LONGITUDE: 121° 25.3' W (-121.42250)
The bench mark is located 160 m (525 ft) ESE from the intersection of N. Holt
Rd. and Windmill Cove Rd., 47.55 m (156 ft) south of the centerline of Windmill
Cove Rd. and 23.59 m (77.4 ft) SE of the center of the NW concrete anchor block.
The bench mark is cemented into the upper surface of the NE corner of concrete
base of the latticed steel transmission tower.
BENCH MARK STAMPING: 5021 B 1977
DESIGNATION: 941 5021 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 8502
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 37° 59.6' N ( 37.99380) LONGITUDE: 121° 25.2' W (-121.41937)
The bench mark is located 160 m (525 ft) east from the intersection of N. Holt
Rd. and Windmill Cove Rd., 86 m (260 ft) south of the centerline of Windmill
Cove Rd., 0.6 m (2 ft) west of a telephone pole, and 0.1 m (0.2 ft) above grade.
The bench mark is on a rod driven 11 m (35 ft), and encased in a PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9415021 PUBLICATION DATE: 09/28/2016
Name: BLACKSLOUGH LANDING, SAN JOAQUIN RIVER
CA
NOAA Chart: 18661 Latitude: 37° 59.7' N ( 37.99469)
USGS Quad: HOLT Longitude: 121° 25.1' W (-121.41904)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5021 E 2014
DESIGNATION: 941 5021 E
MONUMENTATION: Tidal Station disk VM#: 21999
AGENCY: US Army Corps of Engineers (USACE) IDB PID#:
SETTING CLASSIFICATION: Concrete Base OPUS PID:
LATITUDE: 37° 59.7' N ( 37.99428) LONGITUDE: 121° 25.4' W (-121.42261)
The bench mark is located 160 m (525 ft) ESE from the intersection of N. Holt
Rd. and Windmill Cove Rd., 24.72 m (88.1 ft ) south of the centerline of
Windmill Cove Rd. and 23.90 m (78.4 ft) NW of the center of the concrete base of
the latticed steel transmission tower. The bench mark is cemented into the upper
surface of the SE corner of NW concrete anchor block.
BENCH MARK STAMPING: 5021 D 2014
DESIGNATION: 941 5021 D
MONUMENTATION: Tidal Station disk VM#: 22000
AGENCY: US Army Corps of Engineers (USACE) IDB PID#:
SETTING CLASSIFICATION: Concrete base OPUS PID:
LATITUDE: 37° 59.6' N ( 37.99414) LONGITUDE: 121° 25.3' W (-121.42228)
The bench mark is located 160 m (525 ft) ESE from the intersection of N. Holt
Rd. and Windmill Cove Rd., 34.05 m (111.7 ft) south of the centerline of
Windmill Cove Rd., and 24.23 m (79.5 ft) NE of the center of the concrete base
of the latticed steel transmission tower. The bench mark is cemented into the
upper surface of the SW corner of the NE concrete anchor block.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9415021 PUBLICATION DATE: 09/28/2016
Name: BLACKSLOUGH LANDING, SAN JOAQUIN RIVER
CA
NOAA Chart: 18661 Latitude: 37° 59.7' N ( 37.99469)
USGS Quad: HOLT Longitude: 121° 25.1' W (-121.41904)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5021 F 2014
DESIGNATION: 941 5021 F
MONUMENTATION: Tidal Station disk VM#: 22001
AGENCY: US Army Corps of Engineers (USACE) IDB PID#:
SETTING CLASSIFICATION: Concrete base OPUS PID:
LATITUDE: 37° 59.6' N ( 37.99365) LONGITUDE: 121° 25.4' W (-121.42268)
The bench mark is located 160 m (525 ft) ESE from the intersection of N. Holt
Rd. and Windmill Cove Rd., 70.53 m (231.4 ft) south of the centerline of
Windmill Cove Rd., and 25.13 m (82.44 ft) SE of the center of the concrete base
of the latticed steel transmission tower. The bench mark is cemented into the
upper surface of the SW corner of the SE concrete anchor block.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9415021 PUBLICATION DATE: 09/28/2016
Name: BLACKSLOUGH LANDING, SAN JOAQUIN RIVER
CA
NOAA Chart: 18661 Latitude: 37° 59.7' N ( 37.99469)
USGS Quad: HOLT Longitude: 121° 25.1' W (-121.41904)
T I D A L D A T U M S
Tidal datums at BLACKSLOUGH LANDING, SAN JOAQUIN RIVER based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: January 2015 - February 2015
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9415144 PORT CHICAGO, SUISUN BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.109
MEAN HIGH WATER MHW = 0.971
MEAN SEA LEVEL MSL = 0.561
MEAN TIDE LEVEL MTL = 0.555
MEAN LOW WATER MLW = 0.138
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
3 1933 -0.225 -1.196
5021 B 1977 2.191 1.220
5021 E 2014 -0.796 -1.767
5021 D 2014 -0.976 -1.947
5021 F 2014 -0.922 -1.893
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9415021 PUBLICATION DATE: 09/28/2016
Name: BLACKSLOUGH LANDING, SAN JOAQUIN RIVER
CA
NOAA Chart: 18661 Latitude: 37° 59.7' N ( 37.99469)
USGS Quad: HOLT Longitude: 121° 25.1' W (-121.41904)
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.