U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9451152 PUBLICATION DATE: 07/12/2006
Name: MADAN BAY
AK
NOAA Chart: 17385 Latitude: 56° 23.5' N ( 56.39220)
USGS Quad: PETERSBURG (B-1) Longitude: 132° 10.1' W (-132.16900)
To reach the tidal datum from Wrangell, AK, proceed via boat north in Zimovia
Strait towards Stikine River for 4 KM (2 NM) to the entrance to Eastern Passage.
Then turn and proceed SSE in Eastern Passage for 22 KM (11 NM) until reaching
Channel Island. Then turn north into Madan Bay and proceed 3 KM (1.3 NM) from
the mouth of the bay. The tidal bench marks and the tide gauge were located on
the west shore of Madan Bay at approximate position latitude 56 degrees 23.54'
North, and longitude 132 degrees 10.14' West.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0577 B 2005
DESIGNATION: 945 0577 B
MONUMENTATION: Tidal Station disk VM#: 17973
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID:
LATITUDE: 56° 23.5' N ( 56.39170) LONGITUDE: 132° 10.1' W (-132.16800)
The bench mark is a disk set flush in bedrock outcropping, 33 m (108 ft) south
of bench mark 0577 A 2005, 24 m (79 ft) NNW of the rhombus shaped boulder, 1.49
m (4.9 ft) east of the treeline, and 1.10 m (3.3 ft) west of the seaward edge of
the outcropping, and 0.49 m (1.6 ft) above the mean high water line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9451152 PUBLICATION DATE: 07/12/2006
Name: MADAN BAY
AK
NOAA Chart: 17385 Latitude: 56° 23.5' N ( 56.39220)
USGS Quad: PETERSBURG (B-1) Longitude: 132° 10.1' W (-132.16900)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0577 A 2005
DESIGNATION: 945 0577 A
MONUMENTATION: Tidal Station disk VM#: 17972
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID:
LATITUDE: 56° 23.5' N ( 56.39170) LONGITUDE: 132° 10.1' W (-132.16800)
The primary bench mark is a disk set flush in bedrock outcropping, 57 m (187 ft)
NW of the rhombus shaped boulder, 8 m (26 ft) east of the treeline, 1.10 m (3.3
ft) west of the seaward edge of the outcropping, and 0.49 m (1.6 ft) above the
mean higher water line.
BENCH MARK STAMPING: 1152 C 2005
DESIGNATION: 945 1152 C
MONUMENTATION: Tidal Station disk VM#: 17974
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 56° 23.5' N ( 56.39170) LONGITUDE: 132° 10.1' W (-132.16800)
The bench mark is a disk set flush in bedrock located behind a pile of boulders,
21.09 m (69.2 ft) south of bench mark 0577 B 2005, 2.50 m (8.2 ft) NW of the
rhombus shaped boulders, and 0.49 m (1.6 ft) east of the treeline, and 1.49 m
(4.9 ft) above the mean high water line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9451152 PUBLICATION DATE: 07/12/2006
Name: MADAN BAY
AK
NOAA Chart: 17385 Latitude: 56° 23.5' N ( 56.39220)
USGS Quad: PETERSBURG (B-1) Longitude: 132° 10.1' W (-132.16900)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1152 D 2005
DESIGNATION: 945 1152 D
MONUMENTATION: Tidal Station disk VM#: 17975
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 56° 23.5' N ( 56.39170) LONGITUDE: 132° 10.1' W (-132.16800)
The bench mark is set flush in bedrock located amidst a pile of boulders, 28.86
m (94.7 ft) south of bench mark 1152 C 2005, 10.21 m (33.5 ft) north of a 2 m
(6.5 ft) high rounded mossy boulder, 8.20 m (26.9 ft) NE of a water trickle
spilling from the treeline, 3.51 m (11.5 ft) east of the treeline, and 0.09 m
(0.3 ft) above the mean high water line.
BENCH MARK STAMPING: 1152 E 2005
DESIGNATION: 945 1152 E
MONUMENTATION: Tidal Station disk VM#: 17976
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID:
LATITUDE: 56° 23.5' N ( 56.39170) LONGITUDE: 132° 10.1' W (-132.16800)
The bench mark is a disk set flush in a rectangular prism outcropping of
bedrock, 15.79 m (51.8 ft) south of bench mark 1152 D 2005, 10.09 m (33.1 ft) SE
of the water trickle spilling from the treeline, 2.99 m (9.8 ft) SSE of a 2 m
(6.5 ft0 high rounded mossy boulder, and 0.40 m (1.3 ft0 above the mean high
water line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9451152 PUBLICATION DATE: 07/12/2006
Name: MADAN BAY
AK
NOAA Chart: 17385 Latitude: 56° 23.5' N ( 56.39220)
USGS Quad: PETERSBURG (B-1) Longitude: 132° 10.1' W (-132.16900)
T I D A L D A T U M S
Tidal datums at MADAN BAY based on:
LENGTH OF SERIES: 37 DAYS
TIME PERIOD: March 15, 2005 - April 21, 2005
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9450460 KETCHIKAN, TONGASS NARROWS
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 4.947
MEAN HIGH WATER MHW = 4.670
MEAN TIDE LEVEL MTL = 2.566
MEAN SEA LEVEL MSL = 2.563
MEAN LOW WATER MLW = 0.462
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
0577 B 2005 4.830 0.159
0577 A 2005 5.053 0.383
1152 C 2005 5.814 1.144
1152 D 2005 4.926 0.255
1152 E 2005 4.946 0.275
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9451152 PUBLICATION DATE: 07/12/2006
Name: MADAN BAY
AK
NOAA Chart: 17385 Latitude: 56° 23.5' N ( 56.39220)
USGS Quad: PETERSBURG (B-1) Longitude: 132° 10.1' W (-132.16900)
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.