Project Overview

Construction of a new Water Treatment Works (WTW) and connecting pipeline as part of Welsh Water’s Go to Green (G2G) programme, targeting improvements in drinking water quality. 

Works involved construction of 10 separate reinforced concrete structures, which required 7500m3 of concrete, 1050 tonnes of reinforcement, 35000m3 of earthworks and over 3000m of ductile iron pipework installation. Other associated works included site access roads, security fencing, landscaping, construction of two main buildings to house equipment and water treatment facilities and installation of solar panels. 

The pipeline works involved installation of 6km of twin 450mm and 200mm ductile iron mains from Cwmystradllyn Reservoir to the new WTW, through several difficult terrains including rock and peaty areas, crossing several SSSI watercourses and areas within Snowdonia National Park. 

While most of the work took place within the confines of the existing water treatment works, there was an increase in construction traffic to the site, which had the potential to disrupt local residents. To ensure disruption was kept to a minimum a traffic management plan was agreed with the local highways authority, and construction traffic accessed the site from the A487, instead of using the smaller local roads.

Project Gallery


Black and Veatch/Dwr Cymru Welsh Water



Project Value


Contract Period

100 weeks