U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 9414632 PUBLICATION DATE: 01/24/2018 Name: ALAMEDA CREEK, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 35.7' N ( 37.59500) USGS Quad: REDWOOD POINT Longitude: 122° 8.7' W (-122.14500) To reach the tidal bench marks from State Road 17 and the Alvarado-Niles Boulevard exit, proceed west on Alvarado-Niles Boulevard for 1.8 km (1.1 mi) to Union City Boulevard, turn left onto Union City Boulevard and take the second right, then 1.21 km (0.75 mi) to a T junction, turn left and go 0.1 mile (0.2 km) to a one lane road on the right (between an auto junkyard and sewage plant), go through the gate to the sewage plant and then to the T junction at end of the narrow road, turn right and then go behind the pump house, turn left and go up onto the top of the levee, then left on the levee road for 5.6 km (3.5 mi) to the end of the road. The bench marks are on the south side of the creek. The tide gage and staff were on a small platform about 0.40 km (0.25 mi) east of the entrance to the creek. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 4632 A 1976 DESIGNATION: 941 4632 A MONUMENTATION: Tidal Station disk VM#: 8372 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2362 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 37° 35.7' N ( 37.59500) LONGITUDE: 122° 8.7' W (-122.14500) The primary bench mark is a disk located on the southern levee road along the creek, about 122 m (400 ft) east of the end of the levee road, 16.61 m (54.5 ft) north of the south edge of the levee, 7 m (24 ft) south of the vegetation, and 0.55 m (1.8 ft) south of a witness post. The bench mark is crimped to the top of a copper-clad steel rod driven 17.1 m (56 ft) to refusal.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 9414632 PUBLICATION DATE: 01/24/2018 Name: ALAMEDA CREEK, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 35.7' N ( 37.59500) USGS Quad: REDWOOD POINT Longitude: 122° 8.7' W (-122.14500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4632 B 1976 DESIGNATION: 941 4632 B MONUMENTATION: Tidal Station disk VM#: 8373 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2361 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 37° 35.7' N ( 37.59500) LONGITUDE: 122° 8.7' W (-122.14500) The bench mark is a disk located 110 m (360 ft) east of bench mark 4632 A 1976, 16 m (54 ft) north of the south side of the levee, 12 m (38 ft) south of the vegetation on the south bank of the creek, 1.19 m (3.9 ft) SSE of a witness post, and 0.15 m (0.5 ft) above the ground. The bench mark is crimped to the top of a copper-clad steel rod driven 14.6 m (48 ft) to refusal and encased in a PVC pipe. BENCH MARK STAMPING: 4632 C 1976 DESIGNATION: 941 4632 C MONUMENTATION: Tidal Station disk VM#: 8374 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2360 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 37° 35.7' N ( 37.59500) LONGITUDE: 122° 8.7' W (-122.14500) The bench mark is a disk located on the levee road along the south side of the creek, 119 m (390 ft) east of bench mark 4632 B 1976, about 20 m (65 ft) south of the centerline of the creek, 7 m (23 ft) north of the centerline of the road, and 1 m (4 ft) south of a witness post. The bench mark is set 0.15 m (0.5 ft) above ground crimped to the top of a copper-clad steel rod driven 17.1 m (56 ft) to refusal, and encased in a PVC pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 9414632 PUBLICATION DATE: 01/24/2018 Name: ALAMEDA CREEK, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 35.7' N ( 37.59500) USGS Quad: REDWOOD POINT Longitude: 122° 8.7' W (-122.14500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4632 D 1976 DESIGNATION: 941 4632 D MONUMENTATION: Tidal Station disk VM#: 8375 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2358 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 37° 35.7' N ( 37.59500) LONGITUDE: 122° 8.7' W (-122.14500) The bench mark is a disk located 84 m (275 ft) ESE of bench mark 4632 C 1976, about 23 m (75 ft) south of the centerline of the creek, and 1.07 m (3.5 ft) SSW of a witness post. The bench mark is set 0.15 m (0.5 ft) above ground, crimped to the top of a copper-clad steel rod driven 24.4 m (80 ft) to refusal and encased in a 4 inch PVC pipe. BENCH MARK STAMPING: 4632 E 1976 DESIGNATION: 941 4632 E MONUMENTATION: Tidal Station disk VM#: 8376 AGENCY: National Ocean Survey (NOS) IDB PID#: HT2357 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 37° 35.7' N ( 37.59500) LONGITUDE: 122° 8.7' W (-122.14500) The bench mark is a disk located on the north side of the levee at a T-junction of the levee road on the south side of the creek, near a levee road heading south, 134 m (440 ft) ESE of bench mark 4632 D 1976, 36 m (119 ft) NNE of two wooden gate posts, about 30 m (100 ft) SSW of the centerline of the creek, and 1.37 m (4.5 ft) south of a witness post. The bench mark is crimped to the top of a copper-clad steel rod driven 15.3 m (50 ft) to refusal.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 9414632 PUBLICATION DATE: 01/24/2018 Name: ALAMEDA CREEK, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 35.7' N ( 37.59500) USGS Quad: REDWOOD POINT Longitude: 122° 8.7' W (-122.14500) T I D A L D A T U M S Tidal datums at ALAMEDA CREEK, SAN FRANCISCO BAY based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: December 1976 - February 1977 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9414458 SAN MATEO BRIDGE, WEST SIDE Elevations of tidal datums referred to Mean High Water (MHW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.190 MEAN HIGH WATER MHW = 0.000 North American Vertical Datum NAVD88 = -1.947 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MHW 4632 A 1976 1.265 4632 B 1976 1.210 4632 C 1976 0.874 4632 D 1976 1.960 4632 E 1976 0.824
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 9414632 PUBLICATION DATE: 01/24/2018 Name: ALAMEDA CREEK, SAN FRANCISCO BAY CA NOAA Chart: 18651 Latitude: 37° 35.7' N ( 37.59500) USGS Quad: REDWOOD POINT Longitude: 122° 8.7' W (-122.14500) 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.