U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 9415193 PUBLICATION DATE: 08/29/2005 Name: THREE MILE SLOUGH,SAN JOAQUIN R. CA NOAA Chart: 18661 Latitude: 38° 5.2' N ( 38.08670) USGS Quad: JERSEY ISLAND Longitude: 121° 41.1' W (-121.68500) To reach the tidal bench marks from California Highway 160 turn east on Sherman Island levee road 4.8 km (3.0 mi) south of the junction of Highways 2 and 160, continue on the road for 4.8 km (3.0 mi) to Channel Marker No. 1 at the junction of Three Mile Slough and San Joaquin River. The tide gage and staff were located on Channel Marker No. 1. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: TIDAL 4 1977 DESIGNATION: 941 5193 TIDAL 4 MONUMENTATION: Tidal Station disk VM#: 11882 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 38° 5.0' N ( 38.08330) LONGITUDE: 121° 41.1' W (-121.68500) The primary bench mark is a disk located 114.30 m (375.0 ft) NNW of the center of the T-intersection of the dirt and levee road, 94.49 m (310.0 ft) SSW of Channel Marker No. 1, 4.57 m (15.0 ft) west of the centerline of the levee road, and 1.98 m (6.5 ft) north of a witness post. The bench mark is set 0.18 m (0.6 ft) below road level, set on a copper-clad steel rod, driven 19.20 m (63.0 ft) to refusal.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 9415193 PUBLICATION DATE: 08/29/2005 Name: THREE MILE SLOUGH,SAN JOAQUIN R. CA NOAA Chart: 18661 Latitude: 38° 5.2' N ( 38.08670) USGS Quad: JERSEY ISLAND Longitude: 121° 41.1' W (-121.68500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: SHERMAN 1931 1970 DESIGNATION: SHERMAN RESET MONUMENTATION: Tidal Station disk VM#: 11884 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: JS1716 SETTING CLASSIFICATION: Concrete post OPUS PID: LATITUDE: 38° 5.0' N ( 38.08330) LONGITUDE: 121° 41.1' W (-121.68500) The bench mark is a disk set in top of a concrete post 0.06 m (0.2 ft) above ground, 34.75 m (114.0 ft) north of the juncton of farm road leading west, 12.25 m (40.2 ft) SE of bench mark SHERMAN NO 2 1931, 5.43 m (17.8 ft) east of the centerline of levee road, 1.07 m (3.5 ft) WNW of metal pipe 0.15 m (0.5 ft) above grade, 0.61 m (2.0 ft) west of a metal witness post, and 0.30 m (1.0 ft) below grade.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 9415193 PUBLICATION DATE: 08/29/2005 Name: THREE MILE SLOUGH,SAN JOAQUIN R. CA NOAA Chart: 18661 Latitude: 38° 5.2' N ( 38.08670) USGS Quad: JERSEY ISLAND Longitude: 121° 41.1' W (-121.68500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: SHERMAN NO 2 1931 DESIGNATION: SHERMAN RM 2 MONUMENTATION: Reference Mark disk VM#: 11885 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: JS1717 SETTING CLASSIFICATION: Concrete post OPUS PID: LATITUDE: 38° 5.0' N ( 38.08330) LONGITUDE: 121° 41.1' W (-121.68500) The bench mark is a disk set in top of a concrete post 0.06 m (0.2 ft) above ground, 66.75 m (219.0 ft) north of the center of a triangle formed by the junction of a driveway leading west, 3.81 m (12.5 ft) west of the centerline of the levee road, 0.46 m (1.5 ft) south of a witness post, 0.37 m (1.2 ft) east of a fence and level with the road.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 9415193 PUBLICATION DATE: 08/29/2005 Name: THREE MILE SLOUGH,SAN JOAQUIN R. CA NOAA Chart: 18661 Latitude: 38° 5.2' N ( 38.08670) USGS Quad: JERSEY ISLAND Longitude: 121° 41.1' W (-121.68500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: SHERMAN 1931 NO 3 1970 DESIGNATION: SHERMAN RM 3 MONUMENTATION: Reference Mark disk VM#: 11886 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: JS1719 SETTING CLASSIFICATION: Concrete post OPUS PID: LATITUDE: 38° 5.0' N ( 38.08330) LONGITUDE: 121° 41.1' W (-121.68500) The bench mark is a disk set in top of a concrete post flush with the ground, 29.26 m (96.0 ft) north of junction of a farm road leading west, 5.39 m (17.7 ft) south of bench mark SHERMAN 1931 1970, 4.57 m (15.0 ft) east of the centerline of the levee road, and 0.46 m (1.5 ft) below the road. BENCH MARK STAMPING: 5193 A 1992 DESIGNATION: 941 5193 A MONUMENTATION: Tidal Station disk VM#: 11889 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Drill hole OPUS PID#: BBCQ22 LATITUDE: 38° 5.0' N ( 38.08330) LONGITUDE: 121° 41.1' W (-121.68500) The bench mark is a disk set flush into a drill hole in the SW corner of the concrete foundation, located on a concrete foundation of a gas main (designated by a State Lands Commission Mark as PRC NO 74) manhole cover, approximately 2.50 m x 2.50 m (8.2 ft x 8.2 ft), 13.11 m (43.0 ft) WSW of a PG&E gas pipeline crossing sign on the offshore side of the levee road, 10.06 m (33.0 ft) SE of PG&E Utility Pole No. GT 96477, 6.10 m (20.0 ft) WSW (shore-side) of the centerline of the levee road, and 0.15 m (0.5 ft) above the levee road.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 9415193 PUBLICATION DATE: 08/29/2005 Name: THREE MILE SLOUGH,SAN JOAQUIN R. CA NOAA Chart: 18661 Latitude: 38° 5.2' N ( 38.08670) USGS Quad: JERSEY ISLAND Longitude: 121° 41.1' W (-121.68500) T I D A L D A T U M S Tidal datums at THREE MILE SLOUGH,SAN JOAQUIN R. based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: July 15,1992 - September 14,1992 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 = 1.042 MEAN HIGH WATER MHW = 0.898 MEAN SEA LEVEL MSL = 0.536 MEAN TIDE LEVEL MTL = 0.528 MEAN LOW WATER MLW = 0.159 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW TIDAL 4 1977 3.667 2.769 SHERMAN 1931 1970 3.886 2.988 SHERMAN NO 2 1931 4.012 3.114 SHERMAN 1931 NO 3 1970 3.939 3.042 5193 A 1992 3.691 2.794
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 9415193 PUBLICATION DATE: 08/29/2005 Name: THREE MILE SLOUGH,SAN JOAQUIN R. CA NOAA Chart: 18661 Latitude: 38° 5.2' N ( 38.08670) USGS Quad: JERSEY ISLAND Longitude: 121° 41.1' W (-121.68500) 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.