U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 8638449 PUBLICATION DATE: 04/29/2003 Name: CLAREMONT, JAMES RIVER VA NOAA Chart: 12251 Latitude: 37° 13.9' N ( 37.23170) USGS Quad: CLAREMONT Longitude: 76° 56.9' W ( -76.94830) To reach the tidal bench marks from the Claremont Post Office, proceed east on County Road T 613 for 1.1 km (0.7 mi) and then SE on County Road T 1202 for 0.3 km (0.2 mi) to the circle at the end of the road. The bench marks are near the center of the circle at the end of the road, and along the south bank of James River. The tide gage and staff were at the NE end of an abandoned Navy pier. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: BM 6 1951 DESIGNATION: 863 8449 BM 6 MONUMENTATION: Tidal Station disk VM#: 3456 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Water tower foundation OPUS PID: LATITUDE: 37° 13.9' N ( 37.23170) LONGITUDE: 76° 56.9' W ( -76.94830) The primary bench mark is a disk set in the SW corner of the westernmost of the two northern concrete foundations of the legs of the water tower located about midway between the abandoned Navy pier and the Claremont-Sandy Point ferry slip, 6.1 m (20 ft) east of the property line fence at the gate, and 0.3 m (1 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 8638449 PUBLICATION DATE: 04/29/2003 Name: CLAREMONT, JAMES RIVER VA NOAA Chart: 12251 Latitude: 37° 13.9' N ( 37.23170) USGS Quad: CLAREMONT Longitude: 76° 56.9' W ( -76.94830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 7 1970 DESIGNATION: TIDAL 7 STA 81 MONUMENTATION: Tidal Station disk VM#: 3457 AGENCY: National Ocean Survey (NOS) IDB PID#: GV0448 SETTING CLASSIFICATION: Boat ramp OPUS PID: LATITUDE: 37° 13.8' N ( 37.23000) LONGITUDE: 76° 57.0' W ( -76.95000) The bench mark is a disk set in the top of the west corner of a boat ramp leading to the James River from the garage of a concrete block house along County Road T 1202, 30.94 m (101.5 ft) NW of Bench Mark A 453, 19.5 m (64 ft) NW of the centerline of the road along the NW side of the circle at the end of the road, 9.1 m (30 ft) SW of the approximate shoreline, and 0.67 m (2.2 ft) east of the north corner of the house. BENCH MARK STAMPING: NO 8 1970 DESIGNATION: 863 8449 TIDAL 8 MONUMENTATION: Tidal Station disk VM#: 3458 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Driveway OPUS PID: LATITUDE: 37° 13.9' N ( 37.23170) LONGITUDE: 76° 56.9' W ( -76.94830) The bench mark is a disk set in the driveway of the seventh house east of Bench Mark BM 6 1951, 0.18 m (0.6 ft) from the garage door.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 8638449 PUBLICATION DATE: 04/29/2003 Name: CLAREMONT, JAMES RIVER VA NOAA Chart: 12251 Latitude: 37° 13.9' N ( 37.23170) USGS Quad: CLAREMONT Longitude: 76° 56.9' W ( -76.94830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: A 453 1971 DESIGNATION: A 453 MONUMENTATION: Bench Mark disk VM#: 3459 AGENCY: National Geodetic Survey (NGS) IDB PID#: GV0447 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 37° 13.8' N ( 37.23000) LONGITUDE: 76° 57.1' W ( -76.95170) The bench mark is a disk located near the center of a circle at the end of County Road T 1202, 20.4 m (67 ft) SE of the east corner of a concrete block house, 14.3 m (47 ft) NW of the centerline of the road along the SE side of the circle, 11.3 m (37 ft) SE of the centerline of the road along the NW side of the circle, 10.7 m (35 ft) north of a 0.6 m (2 ft) diameter oak tree, and 0.46 m (1.5 ft) NW of a metal witness post. The bench mark is crimped to a copper-clad steel rod driven 21.9 m (72 ft) to refusal, and encased in a 4-inch metal pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 8638449 PUBLICATION DATE: 04/29/2003 Name: CLAREMONT, JAMES RIVER VA NOAA Chart: 12251 Latitude: 37° 13.9' N ( 37.23170) USGS Quad: CLAREMONT Longitude: 76° 56.9' W ( -76.94830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: B 453 1971 DESIGNATION: B 453 MONUMENTATION: Bench Mark disk VM#: 3460 AGENCY: National Geodetic Survey (NGS) IDB PID#: GV0449 SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 37° 13.8' N ( 37.23000) LONGITUDE: 76° 57.0' W ( -76.95000) The bench mark is a disk located in the vicinity of the abandoned Navy pier, 118.9 m (390 ft) NE of the centerline of County Road T 1202, 80.5 m (264 ft) SE of the center of the circle at the end of the road, 26.8 m (88 ft) north of the north porch corner for a one story residence, 21.0 m (69 ft) SW of the SW end of the abandoned Navy pier, 15.5 m (51 ft) SW of the approximate shoreline, and 0.46 m (1.5 ft) SW of a metal witness post. The bench mark is crimped to a copper-clad steel rod driven 21.6 m (71 ft) to refusal and encased in a 4-inch steel pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 8638449 PUBLICATION DATE: 04/29/2003 Name: CLAREMONT, JAMES RIVER VA NOAA Chart: 12251 Latitude: 37° 13.9' N ( 37.23170) USGS Quad: CLAREMONT Longitude: 76° 56.9' W ( -76.94830) T I D A L D A T U M S Tidal datums at CLAREMONT, JAMES RIVER based on: LENGTH OF SERIES: 36 MONTHS TIME PERIOD: February 1971 - January 1974 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8638610 SEWELLS POINT, HAMPTON ROADS Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: HIGHEST OBSERVED WATER LEVEL (10/06/1972) = 1.391 MEAN HIGHER HIGH WATER MHHW = 0.647 MEAN HIGH WATER MHW = 0.589 MEAN SEA LEVEL MSL = 0.334 MEAN TIDE LEVEL MTL = 0.317 MEAN LOW WATER MLW = 0.045 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (01/27/1971) = -0.841 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW BM 6 1951 1.555 0.966 NO 7 1970 1.496 0.907 NO 8 1970 1.694 1.105 A 453 1971 1.305 0.716 B 453 1971 1.094 0.505
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 8638449 PUBLICATION DATE: 04/29/2003 Name: CLAREMONT, JAMES RIVER VA NOAA Chart: 12251 Latitude: 37° 13.9' N ( 37.23170) USGS Quad: CLAREMONT Longitude: 76° 56.9' W ( -76.94830) 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.