Beacon Hill Reservoir
A major programme of works to double capacity at Beacon Hill Reservoir in Oxfordshire, boosting water available to customers and safeguarding future supplies.
This multi-million pound, design and construct contract for Thames Water was for a 45 megalitre (45 million litres) twin cell reservoir that would provide sufficient water to meet expected population growth and rising demand until 2020.
Beacon Hill Reservoir is strategic to water supplies for Swindon, Oxford city and Banbury. The expansion will enable the full reservoir complex to supply in total, up to 90 million litres of water per day to 150,000 customers in a 30 mile radius.
Beacon Hill is an underground service reservoir for the storage of treated drinking water. It is supplied by water treatment works at Farmoor, Swinford (Oxfordshire) and Cleeve (Berkshire).
Two, 22½ megalitre, nine meter deep storage tanks have been constructed, 60 metres long and 45 metres wide. The founding clay strata imposed potential ground movement from heave and settlement that was incorporated within the robust design.
The discovery of badger setts at this environmentally sensitive site meant the relocation and redesign of the reservoir at an early stage. The subsequent 98 week programme of works will be delivered to time and budget.
The contract has involved the removal of 112,000 cubic metres of clay. To minimise disruption and avoid the necessity for 57,000 cubic metres of surplus soil to be removed to landfill, arrangements were made for it to be spread across fields belonging to a local landowner. This took the equivalent of 5,000 lorry movements off local roads. Of the remainder, 30,000 cubic metres was reused on site as backfill and a further 25,000 cubic metres for re-profiling works.