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.
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
| Location | |
| Latitude | 52° 43.14'N |
| Longitude | 4° 2.682'W |
| Grid ref | SH 6197 1548 |
| Earliest data | 1991 |
| Tidal levels | |
| HAT | 5.69 m |
| LAT | 0.32 m |
| MHWS | 5.05 m |
| MHWN | 3.66 m |
| MLWN | 1.83 m |
| MLWS | 0.80 m |
| H for 2023 | 5.61 m |
| L for 2023 | 0.38 m |
| H for 2024 | 5.65 m |
| L for 2024 | 0.36 m |
| MSR | 4.25 m |
| MNR | 1.83 m |
Abbreviations
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 devices
Tide gauge systemsFull-tide bubbler
Half-tide bubbler
Direct pressure transducer
Tide gauges
Ott pneumatic gauge
Munro float gauge
Wellhead float gauge
Lea float gauge
Instruments
DATARING logger
Datum probe