Datums for 9451321, Castle Islands, AK AK


NOTICE: All data values are relative to the MLLW.

Elevations on Mean Lower Low Water

Station: 9451321, Castle Islands, AK, AK
Status: Accepted (May 19 2025)
Units: Feet
Control Station: 9450460 Ketchikan, AK
T.M.: 0
Epoch: 1983-2001
Datum: MLLW
DatumValueDescription
MHHW15.83Mean Higher-High Water
MHW14.94Mean High Water
MTL8.23Mean Tide Level
MSL8.01Mean Sea Level
DTL7.91Mean Diurnal Tide Level
MLW1.51Mean Low Water
MLLW0.00Mean Lower-Low Water
NAVD883.20North American Vertical Datum of 1988
STND-15.84Station Datum
GT15.83Great Diurnal Range
MN13.43Mean Range of Tide
DHQ0.88Mean Diurnal High Water Inequality
DLQ1.52Mean Diurnal Low Water Inequality
HWI9.80Greenwich High Water Interval (in hours)
LWI3.29Greenwich Low Water Interval (in hours)
Max TideHighest Observed Tide
Max Tide Date & Time Highest Observed Tide Date & Time
Min TideLowest Observed Tide
Min Tide Date & Time Lowest Observed Tide Date & Time
HAT20.15Highest Astronomical Tide
HAT Date & Time11/15/2016 22:06HAT Date and Time
LAT-4.75Lowest Astronomical Tide
LAT Date & Time05/27/2021 16:18LAT Date and Time
Tidal Datum Analysis Periods
05/01/2024 - 07/31/2024




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