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Llyfni water levels

1 gauge, at Afon Llyfni - Pont Y Cim River Station. It is not above its typical high. 1 storm overflow upstream is discharging now. Gauges in Gwynedd; levels are checked every 15 minutes.

1gauge
0above normal
1overflow upstream discharging

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Gauges

Monitoring stations, source to mouth

StationTownLevel nowStatusTrend
Afon Llyfni - Pont Y Cim River Station—0.49 m 17m agoWithin its typical range—

Stations are listed from source to mouth as the water flows, traced on the river map (OS Open Rivers) and the Environment Agency’s own links between its gauges. A distance “by river” is along the river, and is shown only where the map traces the path.

Contains OS data © Crown copyright and database rights 2026.

Gauged tributaries

Streams and rivers with a gauge whose water joins the Llyfni above one of its gauges, from the source down. The river map knows where gauges are, not every stream, so a tributary without a gauge is not listed here.

No gauged tributary joins the Llyfni above Afon Llyfni - Pont Y Cim River Station on the river map. Streams without a gauge are not counted here.

Where the Llyfni goes

No gauge below Afon Llyfni - Pont Y Cim River Station is known on the river map.

Tributaries and where they join are traced on the river map (OS Open Rivers, edition 2026-04) and the Environment Agency’s links between its gauges. The map holds distances between gauges, not the junctions themselves, so a junction is placed between two gauges, and no further up than the tributary’s own lowest gauge. Contains OS data © Crown copyright and database rights 2026.

Storm overflows upstream

3 storm overflows are traced upstream of Afon Llyfni - Pont Y Cim River Station, the Llyfni’s lowest gauge on the river map: on the Llyfni itself, on its gauged tributaries, and on smaller streams that join above there.

  • 1 reports discharging now
  • 2 not discharging
  • 0 offline or silent: 0 monitor offline, 0 status unknown, 0 no live feed

Official figures for 2025, for the overflows traced upstream of Afon Llyfni - Pont Y Cim River Station: 182 spills over 1,397 hours in total, across all 3.

Each overflow is listed in the stretch above the first gauge its water reaches, from the source down, as on the Gauges tab. A stretch of the Llyfni includes the smaller streams that join it there.

Above Afon Llyfni - Pont Y Cim River Station, the Llyfni’s highest gauge3 overflows · 1 discharging now
  • Talysarn Bridge Storm Overflow Not discharging
    Dwr Cymru Welsh Water · into Unnamed Tribuatary Of Afon Llyfni · 6.3 km by river above Afon Llyfni - Pont Y Cim River Station · 2025: 87 spills, 568 h
  • Talysarn Gas Works Storm Overflow Discharging now since
    Dwr Cymru Welsh Water · into Unnamed Tribuatary Of Afon Llyfni · 5.7 km by river above Afon Llyfni - Pont Y Cim River Station · 2025: 86 spills, 828 h
  • Rhedyw Road Llanllyfni Overflow Not discharging
    Dwr Cymru Welsh Water · into River Llynfi · 4.2 km by river above Afon Llyfni - Pont Y Cim River Station · 2025: 9 spills, 2.3 h · placed on the river by its position alone

Near these gauges, connection not known

Within 3 km of one of the Llyfni’s gauges in a straight line, but the river map cannot say whether their water reaches it.

  • Aberdesach Storm Overflow Not discharging
    Dwr Cymru Welsh Water · into Afon Desach · 1.8 km from Afon Llyfni - Pont Y Cim River Station in a straight line · its water cannot be followed on the map · 2024: 92 spills, 186 h
  • Llanllyfni WwTW Storm Overflow Discharging now since
    Dwr Cymru Welsh Water · into River Llynfi · 2.1 km from Afon Llyfni - Pont Y Cim River Station in a straight line · several watercourses close by, nothing to choose between them · 2025: 113 spills, 1,505 h
  • Llanllyfni Glan Aber Storm Overflow Not discharging
    Dwr Cymru Welsh Water · into River Loughor · 2.9 km from Afon Llyfni - Pont Y Cim River Station in a straight line · several watercourses close by, nothing to choose between them · 2025: 130 spills, 341 h
  • Penygroes Storm Overflow Not discharging
    Dwr Cymru Welsh Water · into River Llynfi · 3.0 km from Afon Llyfni - Pont Y Cim River Station in a straight line · its recorded watercourse is not the one mapped beside it · 2025: 53 spills, 75 h

3 other overflows within 3 km of these gauges are placed below the Llyfni’s lowest gauge or on another river, so not listed.

A status is the water company’s own monitor: it says whether an overflow is discharging, never how much or why, and a spill does not by itself explain a change in a river level. A status older than two hours is shown as unknown. Annual figures are the official returns: 12/24-hour spills for England and Wales, overflow events for Scotland (Scottish Water counts differently, so the two cannot be compared). “No data” means the monitor produced no usable data that year, not zero. Overflows are placed on OS Open Rivers (edition 2026-04), which leaves out many small channels: an overflow the map cannot place may still drain here. Contains OS data © Crown copyright and database rights 2026. Sewage in Britain’s rivers →

Live status: © Dŵr Cymru Welsh Water, from its Storm Overflow Map. Annual figures for Wales: Dŵr Cymru Welsh Water’s return to Natural Resources Wales, as compiled by The Rivers Trust, Open Government Licence.