Barmouth tide gauge site

The Barmouth (Abermaw) tide gauge is located in the toll booth on the north end of the Barmouth railway bridge which crosses the River Mawddach. The pressure points are attached to the first pier of the railway bridge in the deep channel as shown.
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Tide gauge location

The tide gauge equipment is housed in a heated instrument cabinet. The system consists of a pneumatic bubbler with two full tide and mid-tide pressure points. All measuring systems are monitored by the POL data logger.

Tide gauge location The tide gauge is levelled to the tide gauge bench mark supported by Ordnance Survey auxiliary marks.

External users

Sea level pressures and/or elevations from this site are supplied to the following authority:

  • Meirionnydd District Council

Site history

1991 – DATARING system with two full tide pressure points installed
2001 – New POL data logger installed recording the two full tide sensors
2003 – System removed for the refurbishment of the bridge
2005 – Tide gauge system reinstalled with a mid-tide sensor

Latitude52° 43.14'N
Longitude4° 2.682'W
Grid refSH 6197 1548
Earliest data1991
Tidal levels
HAT5.69 m
LAT0.32 m
MHWS5.05 m
MHWN3.66 m
MLWN1.83 m
MLWS0.80 m
H for 2024 5.65 m
L for 2024 0.36 m
H for 2025 5.57 m
L for 2025 0.49 m
MSR4.25 m
MNR1.83 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

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