U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 8630316 PUBLICATION DATE: 08/03/2004 Name: HARBOR OF REFUGE, CHINCOTEAGUE VA NOAA Chart: 12211 Latitude: 37° 54.2' N ( 37.90330) USGS Quad: CHINCOTEAGUE WEST Longitude: 75° 24.4' W ( -75.40670) To reach the tidal bench marks from the junction of Main Street and State Route 175 at Chincoteague, proceed 4.2 km (2.6 mi) south along Main Street (State Road 2114) to the entrance for Harbor of Refuge, on the left. The bench marks are along Main Street and at the Harbor of Refuge. The tide gage and staff were located on a dock owned by the town of Chincoteague in the Harbor of Refuge. 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 6 Station ID: 8630316 PUBLICATION DATE: 08/03/2004 Name: HARBOR OF REFUGE, CHINCOTEAGUE VA NOAA Chart: 12211 Latitude: 37° 54.2' N ( 37.90330) USGS Quad: CHINCOTEAGUE WEST Longitude: 75° 24.4' W ( -75.40670) T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 2 1962 DESIGNATION: TIDAL 2 STA 5 MONUMENTATION: Tidal Station disk VM#: 3264 AGENCY: US Coast & Geodetic Survey (USC&GS) IDB PID#: FW0142 SETTING CLASSIFICATION: Concrete-filled terra cotta pipe OPUS PID: LATITUDE: 37° 54.3' N ( 37.90500) LONGITUDE: 75° 24.4' W ( -75.40670) The primary bench mark is a disk set in the top of a concrete-filled terra cotta pipe projecting about 0.15 m (0.5 ft) above ground, 70 m (230 ft) east of the centerline of Main Street at a side road entrance, 65 m (212 ft) east of power pole ESPSC of VA. 17 with transformer, 19 m (63 ft) NNW of third USCG telephone pole and 26 m (86 ft) SSE of the fourth USCG telephone pole.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 8630316 PUBLICATION DATE: 08/03/2004 Name: HARBOR OF REFUGE, CHINCOTEAGUE VA NOAA Chart: 12211 Latitude: 37° 54.2' N ( 37.90330) USGS Quad: CHINCOTEAGUE WEST Longitude: 75° 24.4' W ( -75.40670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 3 1962 DESIGNATION: TIDAL 3 STA 5 MONUMENTATION: Tidal Station disk VM#: 3265 AGENCY: US Coast & Geodetic Survey (USC&GS) IDB PID#: FW0143 SETTING CLASSIFICATION: Concrete-filled terra cotta pipe OPUS PID: LATITUDE: 37° 54.3' N ( 37.90500) LONGITUDE: 75° 24.4' W ( -75.40670) The bench mark is a disk set in the top of a concrete-filled terra cotta pipe, 78 m (255 ft) NW of bench mark NO 2 1962, 43 m (140 ft) SE of power pole ESPSC of VA. (first pole north of the pole with a transformer attached), 38 m (126 ft) west of the fifth USCG telephone pole from south, and 30 m (100 ft) north of middle cottage of three one-room cottages. BENCH MARK STAMPING: 863 0316 A 1977 DESIGNATION: 863 0316 A TIDAL MONUMENTATION: Tidal Station disk VM#: 3266 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 37° 54.2' N ( 37.90330) LONGITUDE: 75° 24.4' W ( -75.40670) The bench mark is a disk set in a concrete monument, 61 m (200 ft) NE of the tide staff, 51.91 m (170.3 ft) west of a power pole near the end of a boat basin, 8.02 m (26.3 ft) south of a wooden fence between an oyster shell ramp and a bush area, and flush with the ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 8630316 PUBLICATION DATE: 08/03/2004 Name: HARBOR OF REFUGE, CHINCOTEAGUE VA NOAA Chart: 12211 Latitude: 37° 54.2' N ( 37.90330) USGS Quad: CHINCOTEAGUE WEST Longitude: 75° 24.4' W ( -75.40670) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 863 0316 B 1977 DESIGNATION: 863 0316 B TIDAL MONUMENTATION: Tidal Station disk VM#: 3267 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 37° 54.2' N ( 37.90330) LONGITUDE: 75° 24.4' W ( -75.40670) The bench mark is a disk set in a concrete monument, 61 m (200 ft) SW of the entrance to the Harbor of Refuge, 17.47 m (57.3 ft) SE of the SE corner of a bath house on Tull's Camp Site, 5.61 m (18.4 ft) south of the centerline of Main Street (State Road 2114), and 9 cm (0.3 ft) below the surface of a small ridge. BENCH MARK STAMPING: 863 0308 C 1977 DESIGNATION: 863 0308 C TIDAL MONUMENTATION: Tidal Station disk VM#: 3268 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 37° 54.2' N ( 37.90330) LONGITUDE: 75° 24.4' W ( -75.40670) The bench mark is a disk set in a concrete monument, 3.7 km (2.3 mi) south of the junction of Main Street and State Highway 175 along Main Street (State Road 2114), past a culvert under the road and a boat launching ramp to a large open parking area on the right, 58.06 m (190.5 ft) NE of the east corner of Mr. Minnick's trailer, 4.75 m (15.6 ft) NW of the centerline of the road, 4.72 m (15.5 ft) SE of a power pole and flush with the ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 8630316 PUBLICATION DATE: 08/03/2004 Name: HARBOR OF REFUGE, CHINCOTEAGUE VA NOAA Chart: 12211 Latitude: 37° 54.2' N ( 37.90330) USGS Quad: CHINCOTEAGUE WEST Longitude: 75° 24.4' W ( -75.40670) T I D A L D A T U M S Tidal datums at HARBOR OF REFUGE, CHINCOTEAGUE based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: July 1977 - August 1977 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8630249 CHINCOTEAGUE, USCG STATION Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.855 MEAN HIGH WATER MHW = 0.782 North American Vertical Datum NAVD88 = 0.469 MEAN TIDE LEVEL MTL = 0.412 MEAN SEA LEVEL MSL = 0.411 MEAN LOW WATER MLW = 0.041 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW NO 2 1962 1.496 0.714 NO 3 1962 1.321 0.539 863 0316 A 1977 1.396 0.614 863 0316 B 1977 1.841 1.059 863 0308 C 1977 1.674 0.892
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 8630316 PUBLICATION DATE: 08/03/2004 Name: HARBOR OF REFUGE, CHINCOTEAGUE VA NOAA Chart: 12211 Latitude: 37° 54.2' N ( 37.90330) USGS Quad: CHINCOTEAGUE WEST Longitude: 75° 24.4' W ( -75.40670) 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.