SWOAPG is aware that the reservoir release this week had a surprisingly significant impact mid-morning on the water level in Porth yr Ogof (it was close to the top of the entrance walkway slab, although not for long and it did drop quickly). We have asked Dwr Cymru if they can provide more detail for future scheduled releases so that we can better predict what impact they might have!

We have received the following message from Dwr Cymru Welsh Water – they aren’t anticipating any ‘increased flooding risk’ but anyone planning to operate in Porth yr Ogof or the Mellte gorge on Thursday might like to be aware of this event:

“As responsible reservoir undertakers Dwr Cymru Welsh Water are planning on testing the operation of the reservoir scour valve(s) at Ystradfellte on 7/04/2022. The test involves a short opening of the bottom outlet valve(s) of the reservoir to ensure its efficient functioning. This is a statutory requirement by Welsh Water under the Reservoirs Act 1975 of which DCWW has received consent to carry out from NRW as per consent NRWWIA201 dated 16th December 2020 and provides consent until the 21st January 2026.

“We are writing to you to inform you that we do not envisage any problems with any increased flooding risk downstream or the possible release of turbid water during this short release and there are no algal blooms present.

“If you have any queries in relation to the above then please do not hesitate to give us a call (01792 315701).”