Cynwyl Elfed WwTW Storm Overflow

Year by year

Dŵr Cymru Welsh Water's annual Event Duration Monitoring return to Natural Resources Wales (12/24-hour spill count), as compiled by The Rivers Trust. 2026 is our own running count, the same way, from the live feed since 28 February (when we began keeping every discharge it reports) — so it can only be lower than the full year. The official figure is published next spring.

"No data" means the monitor was not working or not required to report that year — not zero.

Discharges we have recorded

238 discharge periods since 7 Jul 2021, 1 still open. 238 of them come from Dwr Cymru Welsh Water's own event-duration-monitoring records (published by the company, Jul 2021 – Dec 2021); the live feed adds anything after that. The official annual count is the figure to quote.

• Fri 31 Dec 2021, 13:45
  ongoing
  still discharging · EDM log · 316 blocks
• Wed 29 Dec 2021, 23:45
  1 d 9 h
  ended 10:45 · EDM log · 8 blocks · over 1 d 11 h
• Wed 29 Dec 2021, 21:30
  45 min
  ended 22:30 · EDM log · 2 blocks
• Wed 29 Dec 2021, 17:45
  2 h 15 min
  ended 21:00 · EDM log · 5 blocks · over 3 h 15 min
• Wed 29 Dec 2021, 16:45
  15 min
  ended 17:00 · EDM log
• Wed 29 Dec 2021, 15:45
  15 min
  ended 16:00 · EDM log
• Wed 29 Dec 2021, 15:00
  15 min
  ended 15:15 · EDM log
• Wed 29 Dec 2021, 13:45
  15 min
  ended 14:00 · EDM log
• Wed 29 Dec 2021, 12:45
  15 min
  ended 13:00 · EDM log
• Wed 29 Dec 2021, 07:45
  3 h 30 min
  ended 12:15 · EDM log · 5 blocks · over 4 h 30 min

The year figures above use the EA's 12/24-hour counting method, so they are comparable with the official figures; the monitor log's 746 raw blocks were merged into 238 continuous discharge periods (gaps under 15 min joined).

Concerned about this overflow?

Report pollution you can see or smell to the regulator straight away; the company handles complaints about the overflow itself.