3 gauges from Cwmlanerch River Station to Trefriw TideGauge. None of the 2 that can be compared with a typical high is above it. 5 storm overflows upstream are discharging now. Gauges in Conwy; levels are checked every 15 minutes.
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.
Streams and rivers with a gauge whose water joins the Conwy above one of its gauges, from the source down. Named streams without a gauge that have a page here are listed at the end.
Named streams on the river map that flow into the Conwy and have no gauge of their own. Each has a page with what is known about it: the next gauge downstream, and any storm overflows or water-sampling points placed on it.
Afon Machno (joins about 6.3 km above Cwmlanerch River Station)
Merddwr (joins about 13 km above Cwmlanerch River Station)
Nant y Goron (joins about 640 m above Llanrwst Bont Fawr River Station)
Storm overflows upstream
13 storm overflows are traced upstream of Trefriw TideGauge, the Conwy’s lowest gauge on the river map: on the Conwy itself, on its gauged tributaries, and on smaller streams that join above there.
5 report discharging now
8 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 Trefriw TideGauge: 1,073 spills over 14,124 hours in total, across all 13.
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 Conwy includes the smaller streams that join it there.
Above Cwmlanerch River Station, the Conwy’s highest gauge6 overflows · 3 discharging now
Pentrefoelas WwTW Storm OverflowNot discharging Dwr Cymru Welsh Water · into Afon Merddwr · 14.4 km by river above Cwmlanerch River Station · 2025: 13 spills, 39 h
Cwm Penmachno WwTW Storm OverflowDischarging now since Dwr Cymru Welsh Water · into River Machno · 14.2 km by river above Cwmlanerch River Station · 2025: 300 spills, 6,880 h
Llan Penmachno WwTW Storm OverflowDischarging now since Dwr Cymru Welsh Water · into River Machno · 9.1 km by river above Cwmlanerch River Station · 2025: 73 spills, 658 h
Waterloo Bridge Storm OverflowNot discharging Dwr Cymru Welsh Water · into River Conwy · 2.6 km by river above Cwmlanerch River Station · 2025: 26 spills, 155 h
Betws-Y-Coed Storm OverflowDischarging now since Dwr Cymru Welsh Water · into River Conwy · 1.8 km by river above Cwmlanerch River Station · 2025: 82 spills, 873 h
Betws-Y-Coed Muriau Storm OverflowNot discharging Dwr Cymru Welsh Water · into River Conwy · 1.6 km by river above Cwmlanerch River Station · 2025: 26 spills, 31 h
Lledr, above Afon Lledr River Stationjoins the Conwy above Cwmlanerch River Station2 overflows · 2 discharging now
Dolwyddelan Storm OverflowDischarging now since Dwr Cymru Welsh Water · into Afon Lledr · 6.3 km by river above Afon Lledr River Station · 2025: 29 spills, 86 h
Dolwyddelan WwTW Storm OverflowDischarging now since Dwr Cymru Welsh Water · into Afon Lledr · 5.7 km by river above Afon Lledr River Station · 2025: 176 spills, 3,186 h
Between Cwmlanerch River Station and Llanrwst Bont Fawr River Station1 overflow
Nebo Road Llanrwst Storm OverflowNot discharging Dwr Cymru Welsh Water · into Afon Nant-Y-Goron · 1.7 km by river above Llanrwst Bont Fawr River Station · 2025: 74 spills, 21 h
Between Llanrwst Bont Fawr River Station and Trefriw TideGauge4 overflows
Llanrwst Storm OverflowNot discharging Dwr Cymru Welsh Water · into River Conwy · 4.1 km by river above Trefriw TideGauge · 2025: 4 spills, 9.0 h
Llanrwst WwTW Storm OverflowNot discharging Dwr Cymru Welsh Water · into River Conwy · 3.5 km by river above Trefriw TideGauge · 2025: 90 spills, 428 h
Llanrwst WwTW Settled Storm OverflowNot discharging Dwr Cymru Welsh Water · into River Conwy · 3.5 km by river above Trefriw TideGauge · 2025: 95 spills, 1,151 h
Trefriw Main Storm OverflowNot discharging Dwr Cymru Welsh Water · into River Conwy · 940 m by river above Trefriw TideGauge · 2025: 85 spills, 608 h
Near these gauges, connection not known
Within 3 km of one of the Conwy’s gauges in a straight line, but the river map cannot say whether their water reaches it.
Tan-Y-Fedw Trefriw Storm OverflowNot discharging Dwr Cymru Welsh Water · into Afon Crafnant · 510 m from Trefriw TideGauge in a straight line · discharges into a tidal reach, where the water moves both ways · 2025: 18 spills, 93 h
Trefriw WwTW Storm OverflowNot discharging Dwr Cymru Welsh Water · into River Crafnant · 990 m from Trefriw TideGauge in a straight line · its recorded watercourse is not the one mapped beside it · 2025: 130 spills, 2,013 h
Mill Road Betws-Y-Coed Storm OverflowNot discharging Dwr Cymru Welsh Water · into Afon Lliw · 1.2 km from Cwmlanerch River Station in a straight line · its recorded watercourse is not the one mapped beside it · 2025: 58 spills, 937 h
Betws-Y-Coed WwTW Storm OverflowDischarging now since Dwr Cymru Welsh Water · into Afon Lliw · 1.2 km from Cwmlanerch River Station in a straight line · its recorded watercourse is not the one mapped beside it · 2025: 106 spills, 729 h
Pentre Felin Betws Y Coed OverflowNot discharging Dwr Cymru Welsh Water · into Afon Lliw · 1.6 km from Cwmlanerch River Station in a straight line · no mapped watercourse close enough to be sure · 2025: 3 spills, 6.0 h
Betws-Y-Coed Pentre Ddu Storm OverflowDischarging now since Dwr Cymru Welsh Water · into Afon Lliw · 2.1 km from Cwmlanerch River Station in a straight line · several watercourses close by, nothing to choose between them · 2025: 43 spills, 338 h
FloodRadar
Log inCreate free account