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4 gauges from New Tredegar River Station to Llanedeyrn. None is above its typical high. 3 storm overflows upstream are discharging now. Gauges in Caerphilly, Cardiff; levels are checked every 15 minutes.
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| Station | Level now | Status |
|---|---|---|
| New Tredegar River Station | 0.48 m 18m ago | Within its typical range |
| Bargoed River Station 6.3 km by river | 0.47 m 18m ago | Within its typical range |
| Waterloo Bridge Machen River Station 16.6 km by river | 0.56 m 18m ago | Within its typical range |
| Llanedeyrn 13.9 km by river | 0.74 m 33m ago | Within 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.
Streams and rivers with a gauge whose water joins the Rhymney (Rhymni) above one of its gauges, from the source down. Named streams without a gauge that have a page here are listed at the end.
No gauged tributary joins the Rhymney (Rhymni) above Llanedeyrn on the river map. Streams without a gauge are not counted here.
No gauge below Llanedeyrn 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.
59 storm overflows are traced upstream of Llanedeyrn, the Rhymney (Rhymni)’s lowest gauge on the river map: on the Rhymney (Rhymni) itself, on its gauged tributaries, and on smaller streams that join above there.
Official figures for 2025, for the overflows traced upstream of Llanedeyrn: 2,126 spills over 12,365 hours in total, across all 59.
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 Rhymney (Rhymni) includes the smaller streams that join it there. Where a stretch or a tributary has more than 4, the 3 discharging now or nearest its gauge are listed, the rest are counted, and every one is in that gauge’s “Upstream of here” list. Show every overflow in every stretch →
and 5 more: show all 8 overflows on this stretch → All above New Tredegar River Station, nearest first →
and 9 more: show all 12 overflows on this stretch → All above Bargoed River Station, nearest first →
and 31 more: show all 34 overflows on this stretch → All above Waterloo Bridge Machen River Station, nearest first →
and 2 more: show all 5 overflows on this stretch → All above Llanedeyrn, nearest first →
Within 3 km of one of the Rhymney (Rhymni)’s gauges in a straight line, but the river map cannot say whether their water reaches it.
14 more near these gauges whose connection is not known.
1 other overflow within 3 km of these gauges is placed below the Rhymney (Rhymni)’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.
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