Holyhead tide gauge site
The tide gauge building is located on Salt Island close to the lighthouse in the Port of Holyhead.
Click here to see a map of the site in a separate window.
Tide gauge location
The brick tide gauge building contains two stilling wells. A Munro IH40 chart recorder is mounted over one of the wells. The building also houses the POL data logger and pneumatic control panel. The pressure points are mounted directly below the building.
The tide gauge is levelled to the tide gauge bench mark supported by Ordnance Survey auxiliary marks.
There are currently no external users.
1958 – Lea gauge installed in the inner harbour
1977 – Lea gauge replaced, Ott punch tape recorder installed, Lea gauge removed
1977 – Lege gauge replaced with an Ott R16 gauge
1978 – New tide gauge site established on Salt Island
1978 – DATARING system installed with a full tide bubbler and a potentiometer on the Munro gauge
1991 – Mid-tide bubbler installed
1991 – Ship collided with the tide gauge building causing extensive damage
1991 – Tide gauge building demolished
1992 – Mid-tide pressure point installed
1994 – New tide gauge building constructed
1995 – DATARING system installed with a full tide and mid-tide bubbler and a potentiometer on the Munro gauge
2000 – New POL data logger installed
|Grid ref||SH 2553 8287|
|H for 2023||6.25 m|
|L for 2023||0.13 m|
|H for 2024||6.30 m|
|L for 2024||0.00 m|
HAT – highest astronomical tide
LAT – lowest astronomical tide
MHWS – mean high water springs
MHWN – mean high water neaps
MLWN – mean low water neaps
MLWS – mean low water springs
H – highest for year
L – lowest for year
MSR – mean spring range
MNR – mean neap range
Measurement devicesTide gauge systems
Direct pressure transducer
Ott pneumatic gauge
Munro float gauge
Wellhead float gauge
Lea float gauge