Skanska was appointed through the Welsh Water Alliance Framework to construct a new pumping station at Prioress Mill that would meet the requirements of the habitat directive and the fish & eel regulations on the existing site.

The Technical Aspect:

The existing intake structure abstracts raw water directly from the River Usk and pumps forward to Llandegfedd Reservoir via a 60” pipeline approximately 4.6km in length.  It was identified as a high risk asset with operational and maintenance issues based upon the reliability, age and safety of the installed M & E equipment.

• Constructability – The form of construction was a pre-cast concrete wall and soffit units with continuity between each of the units provided in insitu cast reinforced concrete for both wall and slab interfaces.
• Foundations – Insitu cast concrete blinding and mass concrete levelling strips at various levels to found the precast concrete units forming the intake structure.
• Substructures – The scheme was built up over several levels, with the lower level basement forming the main intake part of the structure used for abstracting water from the River Usk.  Intake structure included cells housing hi lift pumps that elevated the water to pipework supplying Llandegfedd Reservoir.  Upper levels of the structure house the main body of the mechanical and electrical equipment.
• Temporary works – Significant temporary works designs have been undertaken in-house and were issued to the principal contractor for all the planned insitu concrete works.
• Environmental – Due to a large amount of insitu concrete used the pH levels of the River Usk were constantly monitored.  Water from the basement levels during the construction phase were passed through specialist equipment to assist with control of the pH prior to discharge of this water into the river.