U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8724292 PUBLICATION DATE: 05/28/2004 Name: KEMP CHANNEL VIADUCT FL NOAA Chart: 11448 Latitude: 24° 39.7' N ( 24.66170) USGS Quad: SUMMERLAND KEY Longitude: 81° 28.1' W ( -81.46830) To reach the tidal bench marks from the post office in Summerland Key, proceed west on U.S. Highway 1 for 2.1 km (1.3 mi) to the west end of the bridge over Kemp Channel. The bench marks are located on the Cudjoe Key side of the old and new highway bridges. The tide gage and staff were located on the south side of the west abutment of the old bridge, now used as a fishing pier. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 3 1937 DESIGNATION: 872 4292 TIDAL 3 MONUMENTATION: Tidal Station disk VM#: 6904 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AA0180 SETTING CLASSIFICATION: Concrete wing wall OPUS PID: LATITUDE: 24° 39.8' N ( 24.66330) LONGITUDE: 81° 28.0' W ( -81.46670) The primary bench mark is a disk set flush in the NW concrete wing wall of the old U.S. Highway 1 bridge (now used as a fishing pier), 8 m (26 ft) north of the centerline of the old highway, and 1 m (4 ft) below the level of the old highway.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8724292 PUBLICATION DATE: 05/28/2004 Name: KEMP CHANNEL VIADUCT FL NOAA Chart: 11448 Latitude: 24° 39.7' N ( 24.66170) USGS Quad: SUMMERLAND KEY Longitude: 81° 28.1' W ( -81.46830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 1 1937 DESIGNATION: 872 4292 TIDAL 1 MONUMENTATION: Tidal Station disk VM#: 6902 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AA0179 SETTING CLASSIFICATION: Concrete wing wall OPUS PID: LATITUDE: 24° 39.8' N ( 24.66330) LONGITUDE: 81° 28.0' W ( -81.46670) The bench mark is a disk set flush in the SW concrete wing wall of the old U.S. Highway 1 bridge (now used as a fishing pier), 19.96 m (65.5 ft) south of the centerline of the old highway, 3 m (9 ft) east of the west end of the wing wall, 1 m (2 ft) west of the angle and inclined part of the wall, and 3 m (10 ft) below the level of the old highway. BENCH MARK STAMPING: NO 2 1937 DESIGNATION: 872 4292 TIDAL 2 MONUMENTATION: Tidal Station disk VM#: 6903 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AA0178 SETTING CLASSIFICATION: Concrete wing wall OPUS PID: LATITUDE: 24° 39.8' N ( 24.66330) LONGITUDE: 81° 28.0' W ( -81.46670) The bench mark is a disk set flush in the SW concrete wing wall of the old U.S. Highway 1 bridge (now used as a fishing pier), NNE of bench mark NO 1 1937, 5.03 m (16.5 ft) south of the centerline of the old highway, and 1 m (2 ft) below the level of the old highway.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8724292 PUBLICATION DATE: 05/28/2004 Name: KEMP CHANNEL VIADUCT FL NOAA Chart: 11448 Latitude: 24° 39.7' N ( 24.66170) USGS Quad: SUMMERLAND KEY Longitude: 81° 28.1' W ( -81.46830) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4292 E 1982 DESIGNATION: 872 4292 E TIDAL MONUMENTATION: Tidal Station disk VM#: 6905 AGENCY: National Ocean Survey (NOS) IDB PID#: AA0974 SETTING CLASSIFICATION: Bridge abutment foundation OPUS PID: LATITUDE: 24° 39.7' N ( 24.66170) LONGITUDE: 81° 28.1' W ( -81.46830) The bench mark is a disk set flush in the concrete foundation for the west bridge abutment located at the SW corner of the new U.S. Highway 1 bridge, 12.53 m (41.1 ft) WNW of the old highway bridge (now used as a fishing pier), 8.26 m (27.1 ft) south of the centerline of U.S. Highway 1, 0.52 m (1.7 ft) east of the cheekwall, and 2 m (6 ft) below highway level. BENCH MARK STAMPING: 4292 D DESIGNATION: 872 4292 D TIDAL MONUMENTATION: Survey disk VM#: 6906 AGENCY: Florida Department of Transportation (FLDT) IDB PID#: AA0975 SETTING CLASSIFICATION: Concrete guardrail OPUS PID: LATITUDE: 24° 39.7' N ( 24.66170) LONGITUDE: 81° 28.1' W ( -81.46830) The bench mark is a disk set flush in the NW concrete guardrail for the new U.S. Highway 1 bridge, 7.22 m (23.7 ft) north of the centerline of the highway, 2.26 m (7.4 ft) west of the abutment, 1.07 m (3.5 ft) east of the west end of the guardrail, and 1 m (3 ft) above highway level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8724292 PUBLICATION DATE: 05/28/2004 Name: KEMP CHANNEL VIADUCT FL NOAA Chart: 11448 Latitude: 24° 39.7' N ( 24.66170) USGS Quad: SUMMERLAND KEY Longitude: 81° 28.1' W ( -81.46830) T I D A L D A T U M S Tidal datums at KEMP CHANNEL VIADUCT based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: January 1974 - February 1974 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8724211 BIG PINE KEY VIADUCT Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: North American Vertical Datum NAVD88 = 0.400 MEAN HIGHER HIGH WATER MHHW = 0.328 MEAN HIGH WATER MHW = 0.269 MEAN SEA LEVEL MSL = 0.168 MEAN TIDE LEVEL MTL = 0.151 MEAN LOW WATER MLW = 0.033 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 3 1937 3.224 2.955 NO 1 1937 0.978 0.709 NO 2 1937 3.793 3.524 4292 E 1982 4.327 4.058 4292 D 6.770 6.501
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8724292 PUBLICATION DATE: 05/28/2004 Name: KEMP CHANNEL VIADUCT FL NOAA Chart: 11448 Latitude: 24° 39.7' N ( 24.66170) USGS Quad: SUMMERLAND KEY Longitude: 81° 28.1' W ( -81.46830) 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.