Unlike run-of-river schemes, the level of discharge from the new hydro has to reflect Cowlyd Water Treatment Works’ operational requirements. The hydro control system works in parallel with float operated valves in the break pressure tanks to respond to fluctuating demand at the works. Should the hydro fail or require maintenance, any excess water is automatically routed through a bypass system to the works. This ensures an absolutely reliable and secure supply of potable water into the distribution network.
The break pressure tanks serve the two parallel raw water pipes that supply the treatment works; a cast iron water main originally installed in the 1920s and a more recently installed ductile iron water main. Dulas designed and delivered a surge protection relief system to provide extra protection to the raw water mains.
The hydro turbine is directly integrated into the water supply pipeline to the treatment works, which are highly sensitive to fluctuations in water quality. Dulas minimised the risk of damage and/or pollution to the water supply during construction whilst working to maintain a live supply to the works. Dulas worked closely with the client to plan shutdowns or reduced flow periods to enable the new pipework connections. Flexibility was key during construction to ensure that Dwr Cymru Welsh Water could always give priority to their primary function, ‘the supply of potable water’ to their customers.