U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9414519 PUBLICATION DATE: 02/07/2005 Name: MOWRY SLOUGH, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 29.6' N ( 37.49330) USGS Quad: MOUNTAINVIEW Longitude: 122° 2.5' W (-122.04200) To reach the tidal bench marks from the State Highway 17 exit at Thornton Avenue West, go SW for two blocks to Cedar Boulevard, then turn left and go two blocks on Cedar Boulevard to Central Avenue, then turn right and proceed on Central Avenue to Leslie Salt Co., then turn left into the main gate of Leslie Salt Co. and proceed for 0.18 km (0.11 mi) to a chainlink fence, then turn right and continue 0.64 km (0.40 mi) to a T-junction, then turn left and proceed 0.18 km (0.11 mi) to a Y-junction, then turn right and proceed 0.64 km (0.40 mi) to a T-junction, then turn right and proceed 1.05 km (0.65 mi) to a wooden building, then turn right at the Y-junction after the wooden building and proceed 9 m (30 ft) to a Y-junction, then turn left and proceed 1.69 km (1.05 mi) to a T-junction. The tide gage and staff were located on a freestanding piling in the slough, and the bench marks are along the Salt Levee Road. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 4519 A 1976 DESIGNATION: 941 4519 A TIDAL MONUMENTATION: Tidal Station disk VM#: 8314 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2392 SETTING CLASSIFICATION: Unspecified deep rod OPUS PID#: HT2392 LATITUDE: 37° 29.6' N ( 37.49330) LONGITUDE: 122° 2.5' W (-122.04200) The primary bench mark is a disk, 134 m (440 ft) WSW of bench mark 4519 B 1976, 107 m (350 ft) north of the north bank of the slough, 4 m (13 ft) SSE of the centerline of Leslie Salt Company levee road parallel to the slough and 0.76 m (2.5 ft) east of a witness post. The bench mark is crimped to the top of an unspecified deep rod driven 14.6 m (48 ft) to substantial resistance, and encased in a PVC pipe that extends 15 cm (0.5 ft) above grade.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9414519 PUBLICATION DATE: 02/07/2005 Name: MOWRY SLOUGH, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 29.6' N ( 37.49330) USGS Quad: MOUNTAINVIEW Longitude: 122° 2.5' W (-122.04200) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4519 B 1976 DESIGNATION: 941 4519 B TIDAL MONUMENTATION: Tidal Station disk VM#: 8315 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2394 SETTING CLASSIFICATION: Unspecified deep rod OPUS PID: LATITUDE: 37° 29.6' N ( 37.49330) LONGITUDE: 122° 2.5' W (-122.04200) The bench mark is a disk, 152 m (500 ft) north of north bank of the slough, 155 m (445 ft) west of bench mark 4519 C 1976, 134 m (440 ft) ENE of bench mark 4519 A 1976, 21 m (68 ft) SSE of bench mark STA 16 1975 L8 3936, 7 m (22 ft) south of the centerline of the levee road, 0.76 m (2.5 ft) ESE of a witness post, and on south side of Leslie Salt Company levee road parallel to the slough. The bench mark is crimped to the top of an unspecified deep rod driven 17.1 m (56 ft) to substantial resistance, and encased in a PVC pipe that extends 18 cm (0.6 ft) above grade. BENCH MARK STAMPING: 4519 C 1976 DESIGNATION: 941 4519 C TIDAL MONUMENTATION: Tidal Station disk VM#: 8316 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2395 SETTING CLASSIFICATION: Unspecified deep rod OPUS PID: LATITUDE: 37° 29.6' N ( 37.49330) LONGITUDE: 122° 2.5' W (-122.04200) The bench mark is a disk, 152 m (500 ft) north of north bank of the slough, 152 m (500 ft) NNW of beached house boat on the north bank of the slough, 137 m (450 ft) WNW of bench mark 4519 D 1976, 5 m (16 ft) south of the centerline of Leslie Salt Company levee road parallel to the slough, and 1 m (2 ft) WNW of a witness post. The bench mark is set 1 m (3 ft) below road level, crimped to the top of an unspecified deep rod driven 19.5 m (64 ft) to substantial resistance, and encased in a PVC pipe that extends 12 cm (0.4 ft) above the grade.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9414519 PUBLICATION DATE: 02/07/2005 Name: MOWRY SLOUGH, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 29.6' N ( 37.49330) USGS Quad: MOUNTAINVIEW Longitude: 122° 2.5' W (-122.04200) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4519 D 1976 DESIGNATION: 941 4519 D TIDAL MONUMENTATION: Tidal Station disk VM#: 8317 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2396 SETTING CLASSIFICATION: Unspecified deep rod OPUS PID: LATITUDE: 37° 29.6' N ( 37.49330) LONGITUDE: 122° 2.5' W (-122.04200) The bench mark is a disk, 140 m (459 ft) west of bench mark 4519 E 1976, 137 m (450 ft) ESE of bench mark 4519 C 1976, 137 m (450 ft) north of north bank of the slough, 5 m (17 ft) south of the centerline of Leslie Salt Company levee road parallel to the slough, and 1 m (3 ft) NW of a witness post. The bench mark is set 1 m (3 ft) below the road level, crimped to the top of an unspecified deep rod driven 19.8 m (65 ft) to substantial resistance, and encased in a PVC pipe that extends 15 cm (0.5 ft) above the grade. BENCH MARK STAMPING: 4519 E 1976 DESIGNATION: 941 4519 E TIDAL MONUMENTATION: Tidal Station disk VM#: 8318 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2397 SETTING CLASSIFICATION: Unspecified deep rod OPUS PID: LATITUDE: 37° 29.6' N ( 37.49330) LONGITUDE: 122° 2.5' W (-122.04200) The bench mark is a disk located 1.1 km (0.7 mi) west of the junction of the road leading to the duck club, 168 m (550 ft) north of the north bank of the slough, 140 m (459 ft) east of bench mark 4519 D 1976, 2 m (8 ft) SSE of the centerline of Leslie Salt Company levee and parallel to the slough, and 2 m (5 ft) north of a witness post. The bench mark is crimped to the top of an unspecified deep rod driven 15.2 m (50 ft) to substantial resistance, and protected by a PVC pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9414519 PUBLICATION DATE: 02/07/2005 Name: MOWRY SLOUGH, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 29.6' N ( 37.49330) USGS Quad: MOUNTAINVIEW Longitude: 122° 2.5' W (-122.04200) T I D A L D A T U M S Tidal datums at MOWRY SLOUGH, SAN FRANCISCO BAY based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: December 1984 - December 1984 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9414750 ALAMEDA, SAN FRANCISCO BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 2.633 MEAN HIGH WATER MHW = 2.444 MEAN SEA LEVEL MSL = 1.420 MEAN TIDE LEVEL MTL = 1.397 MEAN LOW WATER MLW = 0.351 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 4519 A 1976 3.273 0.829 4519 B 1976 3.295 0.851 4519 C 1976 3.196 0.752 4519 D 1976 3.384 0.940 4519 E 1976 3.569 1.125
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9414519 PUBLICATION DATE: 02/07/2005 Name: MOWRY SLOUGH, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 29.6' N ( 37.49330) USGS Quad: MOUNTAINVIEW Longitude: 122° 2.5' W (-122.04200) 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.