Client- Dwr Cymru Welsh Water

Project Overview

Dwr Cymru Welsh Water (DCWW) commissioned Dulas to provide a turnkey new build hydro solution for Bryn Cowlyd Water Treatment Works. The objective was to secure planning consent for, design and install a 200kW hydropower turbine and powerhouse, integrated into break pressure tanks on the raw water feed. The outcome is a high quality hydro scheme on live pipework that will have a long operating lifetime, be reliable in operation and contain suitable fail-safe systems to ensure there is no compromise to the supply of raw water to the treatment works.

Fail-safe System

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.

Surge Protection

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.

Constructed on live raw water supply

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.

Technical Overview

Power Output

200 kW


ilkes twin jet, high capacity Turgo


Induction generator
Control PanelDulas design, supplied by Bridges Ltd
Gross head (reservoir spill)71m
Design flow475 l/s
Plant duty“Continuous duty” expected to be >95%