U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 7 Station ID: 8724448 PUBLICATION DATE: 02/05/2004 Name: WALTZ KEY FL NOAA Chart: 11445 Latitude: 24° 38.8' N ( 24.64670) USGS Quad: SNIPE KEYS Longitude: 81° 39.2' W ( -81.65330) To reach the tidal bench marks from the west end of the bridge between Big Coppitt Key and Saddlebunch Keys, proceed by boat NW for 2.7 km (1.7 statute mi), then north for 2.9 km (1.8 statute mi) to Waltz Key. The bench marks are located in the middle of the key. The tide gage and staff were located on the west side of the key. 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 7 Station ID: 8724448 PUBLICATION DATE: 02/05/2004 Name: WALTZ KEY FL NOAA Chart: 11445 Latitude: 24° 38.8' N ( 24.64670) USGS Quad: SNIPE KEYS Longitude: 81° 39.2' W ( -81.65330) T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: WALL KEY 2 NO 1 1934 DESIGNATION: WALL KEY 2 RM 1 ALIAS: 1 MONUMENTATION: Reference Mark disk VM#: 9618 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AE4419 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 38.8' N ( 24.64670) LONGITUDE: 81° 39.2' W ( -81.65330) The primary bench mark is a disk set in a concrete monument on a pile, 90 m (295 ft) north of the southern tip of the key, 12.92 m (42.4 ft) SSE of bench mark WALL KEY 2 1934, 0.43 m (1.4 ft) north of a witness post, and 0.30 m (1.0 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 7 Station ID: 8724448 PUBLICATION DATE: 02/05/2004 Name: WALTZ KEY FL NOAA Chart: 11445 Latitude: 24° 38.8' N ( 24.64670) USGS Quad: SNIPE KEYS Longitude: 81° 39.2' W ( -81.65330) T I D A L B E N C H M A R K S BENCH MARK STAMPING: WALL KEY 2 1934 DESIGNATION: WALL KEY 2 ALIAS: 2 MONUMENTATION: Triangulation Station disk VM#: 9617 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AA1118 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 38.8' N ( 24.64670) LONGITUDE: 81° 39.2' W ( -81.65330) The bench mark is a disk set in a concrete monument on a pile, 95 m (311 ft) north of the south end of the key, 25 m (81 ft) west of a witness sign nailed to a tree at the waters edge, 1.71 m (5.6 ft) SSE of an old witness sign nailed to a tree, 0.15 m (0.5 ft) east of a new witness post, and 0.30 m (1.0 ft) above ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 7 Station ID: 8724448 PUBLICATION DATE: 02/05/2004 Name: WALTZ KEY FL NOAA Chart: 11445 Latitude: 24° 38.8' N ( 24.64670) USGS Quad: SNIPE KEYS Longitude: 81° 39.2' W ( -81.65330) T I D A L B E N C H M A R K S BENCH MARK STAMPING: WALL KEY 2 NO 2 1934 DESIGNATION: WALL KEY 2 RM 2 ALIAS: 3 MONUMENTATION: Reference Mark disk VM#: 9619 AGENCY: US Coast and Geodetic Survey (USC&GS) IDB PID#: AE4420 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 24° 38.8' N ( 24.64670) LONGITUDE: 81° 39.2' W ( -81.65330) The bench mark is a disk set in a concrete monument on a pile, about 100 m (330 ft) north of the southern tip of the key, 23.16 m (76.0 ft) NNW of bench mark WALL KEY 2 NO 1 1934, 16.15 m (53.0 ft) NW of bench mark WALL KEY 2 1934, 0.18 m (0.6 ft) east of a witness post, and 0.30 m (1.0 ft) above ground level. BENCH MARK STAMPING: 4448 D 1984 DESIGNATION: 872 4448 D MONUMENTATION: Tidal Station disk VM#: 9620 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 24° 38.8' N ( 24.64670) LONGITUDE: 81° 39.2' W ( -81.65330) The bench mark is a disk located 84 m (275 ft) north of the south end of the key, 14.48 m (47.5 ft) SSE of bench mark WALL KEY 2 1934, 12.34 m (40.5 ft) SW of bench mark 4448 E 1984, and 0.30 m (1.0 ft) ESE of a witness post. The bench mark is 0.24 m (0.8 ft) above ground level, crimped to the top of a stainless steel rod driven 6.1 m (20 ft) to refusal, encased in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 7 Station ID: 8724448 PUBLICATION DATE: 02/05/2004 Name: WALTZ KEY FL NOAA Chart: 11445 Latitude: 24° 38.8' N ( 24.64670) USGS Quad: SNIPE KEYS Longitude: 81° 39.2' W ( -81.65330) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 4448 E 1984 DESIGNATION: 872 4448 E MONUMENTATION: Tidal Station disk VM#: 9621 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 24° 38.8' N ( 24.64670) LONGITUDE: 81° 39.2' W ( -81.65330) The bench mark is a disk located 14 m (45 ft) ESE of bench mark WALL KEY 2 1934, 13 m (43 ft) WSW of a witness sign nailed to a tree at the outer mangrove edge, and 0.37 m (1.2 ft) ESE of a witness post. The bench mark is set 0.24 m (0.8 ft) above ground level, crimped to the top of a stainless steel rod driven 6.1 m (20 ft) to refusal, encased in a PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 7 Station ID: 8724448 PUBLICATION DATE: 02/05/2004 Name: WALTZ KEY FL NOAA Chart: 11445 Latitude: 24° 38.8' N ( 24.64670) USGS Quad: SNIPE KEYS Longitude: 81° 39.2' W ( -81.65330) T I D A L D A T U M S Tidal datums at WALTZ KEY based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: January 1975 - January 1975 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8724580 KEY WEST Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.560 MEAN HIGH WATER MHW = 0.473 MEAN SEA LEVEL MSL = 0.273 MEAN TIDE LEVEL MTL = 0.269 MEAN LOW WATER MLW = 0.065 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW WALL KEY 2 NO 1 1934 0.598 0.125 WALL KEY 2 1934 0.595 0.122 WALL KEY 2 NO 2 1934 0.699 0.226 4448 D 1984 0.673 0.200 4448 E 1984 0.712 0.239 Foot Notes: Bench marks 4448 D 1984 and 4448 E 1984 are based on one differential leveling connection and do not meet the quality control standards of the NOS. Therefore, caution should be used when deriving elevations for these marks.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 7 of 7 Station ID: 8724448 PUBLICATION DATE: 02/05/2004 Name: WALTZ KEY FL NOAA Chart: 11445 Latitude: 24° 38.8' N ( 24.64670) USGS Quad: SNIPE KEYS Longitude: 81° 39.2' W ( -81.65330) 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.