The Reservoir Action Group (RAG) is a campaigning organisation formed in 2001 to prevent development on Llanishen Reservoir in north Cardiff (see map) and to maintain public access to both Llanishen and Lisvane reservoirs.

These reservoirs form the southern end of the historic Brecon to Cardiff water supply system which brought clean water into the city over 100 years ago.  The background to their construction can be read here: The Corporation Waterworks Undertaking. Both reservoirs were declared redundant for water supply purposes in the 1970s, but remain as a valuable resource to North Cardiff

Until 2004, the two reservoirs were owned by Welsh Water.  The public were permitted to walk round both, while on Llanishen there was an active Cardiff Council Sailing School and a Fly Fishing Club.   The embankments of both reservoirs are a Site of Special Scientific Interest (SSSI) due to the presence of a wide variety of grassland fungi;  Lisvane Reservoir is also an SSSI due to its overwintering birds, particularly diving ducks.  The reservoirs are within the Nant Fawr river corridor, one of the four and protected green corridors into the city from the countryside, as defined in Cardiff Council's Local Development Plan.

Western Power Distribution (WPD)


In 2004 the reservoirs were acquired by Western Power Distribution (WPD), and the situation rapidly changed.  Over the following two years the Sailing School disappeared as its lease was not renewed, fly fishing was no longer permitted, and public access was ended with the site being fenced and gates locked.  Prior to this WPD submitted a planning application to partially drain Llanishen Reservoir and to build over 320 houses and apartments.

This was the start of a 10 year planning battle, with RAG in the forefront of the opposition to WPD’s plans.   There was a Public Inquiry in 2006 into the application which subsequently refused planning consent.  Further applications were submitted over the years by WPD for basically similar development proposals but with changes to design, layout and access.  Two further Inquiries were held in 2008 and 2011, both of which refused consent.  RAG was legally represented at these inquiries, and RAG members also gave evidence.

 In 2009, largely through the efforts of RAG, the structure of Llanishen Reservoir was designated as a Listed Building, being of historic interest as part of the Taff Fawr water supply system for Cardiff.  This was a critical issue in the refusal of WPD’s final planning application in 2013 due to the harm their scheme would have caused to the structure and particularly its setting.  The other main reason for refusal was that of unacceptable vehicular access onto Lisvane Road.

Draining of Llanishen Reservoir

In 2010, WPD drained Llanishen Reservoir of its water, claiming that this was required for a safety inspection.  However despite pleas from RAG, for it to be refilled when this was completed, it was left empty.  In 2012, WPD formally had Llanishen Reservoir abandoned as a reservoir under the Reservoirs Act 1975.   This means that before it can be refilled, a professional Reservoir Engineer must inspect and declare the structure safe for it to return to being a reservoir and must also supervise the refill.


Change of Ownership.

In September 2013, WPD sold the reservoirs to Celsa, a Catalan company who took over the Allied Steel and Wire works in Cardiff Bay in 2003.   Its interest in the site is because its steelworks in Cardiff Bay takes water from Lisvane reservoir and it wanted to secure the supply.  Celsa has stated that it is not looking to develop on Llanishen reservoir.


RAG and the future.

The rejection of development schemes and the subsequent new ownership opens a new chapter in the RAG and reservoirs saga.    RAG’s first objective of preventing development on Llanishen Reservoir has been achieved.  The second objective of securing the long-term future of the reservoir is still our aim. In the light of what has happened to the area in the past 10 years with WPD having run down the site environmentally, we now wish to see the area tidied up and improved, the reservoir refilled, and the position of 12 years ago regained with the two reservoirs being a valuable and attractive outdoor resource for outdoor recreational activities and biodiversity.


RAG’s job is thus only partially completed.   There has been a momentous victory over Western Power and its development schemes.   Now we must maintain our membership so that we can continue to be an effective campaigning group with both Celsa and Cardiff Council to secure the long term future of the reservoirs so that they can, once again, be enjoyed by members of the public.