U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) To reach the tidal bench marks from the intersection of State Highway 360 and County Road 624 south of Calao, proceed 9.8 km (6.1 miles) north on County Road 624 to the Lewisetta Marina and General Store. The bench marks are located in the vicinity of the marina and store and the tide gage is located on the fuel pier. 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 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: R 462 1971 DESIGNATION: R 462 MONUMENTATION: Bench Mark disk VM#: 493 AGENCY: National Geodetic Survey (NGS) IDB PID#: GV0156 SETTING CLASSIFICATION: Metal rod on base plate encased in 4 inch Orangeburg pipe OPUS PID#: GV0156 LATITUDE: 37° 59.8' N ( 37.99670) LONGITUDE: 76° 27.8' W ( -76.46330) The primary bench mark is a disk located 52.2 m (171.3 ft) SE of the east corner of the Lewisetta General Store, 37.8 m (124.0 ft) south of the centerline of a gravel road, 16.67 m (54.7 ft) SW of the SW corner of a two story white house, from the SW corner of a 12 x 12 wooden shed, and NNW of a fiberglass witness post. The bench mark is set 0.3 m (1 ft) below grade, crimped to the top of a 1.2 m (4 ft) section of copper clad rod attached to a metal base plate, and encased in a 4 inch Orangeburg pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 2 1959 DESIGNATION: 863 5750 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 494 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: GV0157 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 37° 59.8' N ( 37.99670) LONGITUDE: 76° 27.8' W ( -76.46330) The bench mark is a disk set in a concrete monument on the south side of the Aluminum Boat and Storage Shed at the Lewisetta Marina, 33.68 m (110.5 ft) north of the west corner of the boat rental building, 32.98 m (108.2 ft) NW of the west corner of the Lewisetta General Store, 9.81 m (32.2 ft) west of the south corner of the storage shed, and 9.63 m (31.6 ft) SE of the south corner of a concrete block pump house. Bench Mark Is Set in a Concrete Monument on the South Side of the Aluminum Boat and Storage Shed at the Lewisetta Marina, 33.68 M (110.50 Ft) North of the West Corner of the Boat Rental Building, 32.98 M (108.20 Ft) Nw of the West Corner of the Lewisetta General Store, 9.81 M (32.18 Ft) West of the South Corner of the Storage Shed, and 9.63 M (31.59 Ft) Se of the South Corner of a Concrete Block Pump House.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) T I D A L B E N C H M A R K S BENCH MARK STAMPING: Q 462 1971 DESIGNATION: Q 462 MONUMENTATION: Bench Mark disk VM#: 495 AGENCY: National Geodetic Survey (NGS) IDB PID#: GV0155 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 37° 59.8' N ( 37.99670) LONGITUDE: 76° 27.8' W ( -76.46330) The bench mark is a disk set in a concrete post located on the east side of a two story metal building, 37.64 m (123.5 ft) NW of the centerline of County Road 624, 14.39 m (47.2 ft) SE of the NE corner of the building, 10.76 m (35.3 ft) ENE of the SE corner of the building, and 0.03 m (0.1 ft) below grade. BENCH MARK STAMPING: NO 5 1973 DESIGNATION: 863 5750 TIDAL 5 MONUMENTATION: Tidal Station disk VM#: 496 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete step OPUS PID: LATITUDE: 37° 59.8' N ( 37.99670) LONGITUDE: 76° 27.8' W ( -76.46330) The bench mark is a disk set in the bottom concrete step of the boat rental building located in the vicinity of the fuel pier at the Lewisetta Marina, 20.60 m (67.6 ft) SW of the SW face of the Lewisetta General Store, 13.38 m (43.9 ft) WNW of the steel sign post for the gas pumps, 5.91 m (19.4 ft) north of the shore end of the fuel pier, 2.10 m (6.9 ft) ESE of the WNW corner of the bottom step of the boat rental building, and 0.03 m (0.1 ft) above ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5750 H 1978 DESIGNATION: 863 5750 H MONUMENTATION: Tidal Station disk VM#: 499 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 37° 59.8' N ( 37.99670) LONGITUDE: 76° 27.8' W ( -76.46330) The bench mark is a disk located at the east corner of the Aluminum Boat and Storage Shed at the Lewisetta Marina, 30.17 m (99.0 ft) south of the east corner of a wooden boat shed, 26.36 m (86.5 ft) NW of the NW corner of the Lewisetta General Store, and 0.37 m (1.2 ft) NE of the east corner of the storage shed. The bench mark is crimped to the top of a stainless steel rod driven 14.6 m (48 ft) to refusal, and encased in a PVC pipe with concrete kickblock. BENCH MARK STAMPING: 5750 J 1979 DESIGNATION: 863 5750 J TIDAL MONUMENTATION: Tidal Station disk VM#: 500 AGENCY: National Ocean Survey (NOS) IDB PID#: AJ4589 SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: AJ4589 LATITUDE: 38° 60.0' N ( 38.99950) LONGITUDE: 76° 27.9' W ( -76.46422) The bench mark is a disk located on the east side of County Road 624 at the Lewisetta Chapel, 16.09 m (52.8 ft) NW of the north corner of the Chapel, 5.21 m (17.1 ft) east of the centerline of County Road 624, and 0.49 m (1.6 ft) west of a utility pole. The bench mark is crimped to the top of a stainless steel rod driven 11.0 m (36 ft) to refusal, and encased in a 4 inch PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5750 K 1980 DESIGNATION: 863 5750 K MONUMENTATION: Tidal Station disk VM#: 501 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Galvanized steel rod OPUS PID: LATITUDE: 37° 59.8' N ( 37.99670) LONGITUDE: 76° 27.9' W ( -76.46500) The bench mark is a disk located in the Y junction of County Road 624 and a dirt road near the concrete boat ramp at the Lewisetta Marina, 25.51 m (83.7 ft) ENE of the NE end of the ramp, 7.35 m (24.1 ft) NW of the centerline of County Road 624, 4.23 m (13.9 ft) NNE of the centerline of the south part of the dirt road, and 4.11 m (13.5 ft) south of the centerline of the north part of the dirt road. The bench mark is crimped to the top of a galvanized steel rod driven 14.6 m (48 ft) to refusal, and encased in a PVC pipe with concrete kickblock. BENCH MARK STAMPING: 5750 M 1986 DESIGNATION: 863 5750 M MONUMENTATION: Tidal Station disk VM#: 1624 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 38° 59.9' N ( 38.99830) LONGITUDE: 76° 27.9' W ( -76.46500) The bench mark is a disk located along the west side of County Road 624 in the vicinity of the Lewisetta Marina, 27.74 m (91.0 ft) south of a gravel road leading to a tan house, 7.01 m (23.0 ft) west of the centerline of County Road 624, 3.41 m (11.2 ft) east of TTCO power pole #136 branded 7-25, and 0.30 m (1.0 ft) east of a NOAA witness post. The bench mark is set 0.06 m (0.2 ft) below ground, crimped to the top of a stainless steel rod driven 11.0 m (36 ft) to refusal, and encased in a PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 7 of 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 3 1959 DESIGNATION: 863 5750 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 13557 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 37° 59.8' N ( 37.99670) LONGITUDE: 76° 27.9' W ( -76.46500) The bench mark is a disk set in a concrete monument on top of a small mound located at the 'Y' junction of a dirt road near the ramp at the Lewisetta Marina, 25.51 m (83.7 ft) ENE of the NE end of the concrete boat ramp, 7.32 m (24.0 ft) NW of the centerline of County Road 624, 4.21 m (13.8 ft) NNE of the centerline of the south part of the dirt driveway, and 0.61 m (2.0 ft) east of bench mark 5750 K 1980.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 8 of 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) T I D A L D A T U M S Tidal datums at LEWISETTA, POTOMAC RIVER based on: LENGTH OF SERIES: 19 YEARS TIME PERIOD: January 1983 - December 2001 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: HIGHEST OBSERVED WATER LEVEL (09/01/2006) = 1.721 MEAN HIGHER HIGH WATER MHHW = 0.458 MEAN HIGH WATER MHW = 0.415 North American Vertical Datum NAVD88 = 0.253 MEAN SEA LEVEL MSL = 0.230 MEAN TIDE LEVEL MTL = 0.226 MEAN LOW WATER MLW = 0.036 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (04/05/1975) = -0.869 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW R 462 1971 1.420 1.004 NO 2 1959 1.278 0.863 Q 462 1971 1.219 0.803 NO 5 1973 1.471 1.055 5750 H 1978 1.193 0.777 5750 J 1979 1.346 0.931 5750 K 1980 1.567 1.152 5750 M 1986 1.297 0.882 NO 3 1959 1.542 1.127
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 9 of 9 Station ID: 8635750 PUBLICATION DATE: 10/12/2011 Name: LEWISETTA, POTOMAC RIVER VA NOAA Chart: 12233 Latitude: 37° 59.8' N ( 37.99611) USGS Quad: HEATHSVILLE Longitude: 76° 27.9' W ( -76.46444) 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.