Farmoor Reservoir

Farmoor Reservoir is a public supply reservoir at Farmoor, Oxfordshire, England, about 5 miles (8 km) west of Oxford. It is adjacent to the River Thames. Like most of the reservoirs in the Thames Valley, it is a pumped storage reservoir which was not formed by damming a watercourse in a valley. In this case the banks were raised above the local ground level using material excavated from within the bowl of the reservoir. The reservoir is divided into two: Stage 1 to the north and Stage 2 to the south. The two reservoirs stages are separated by a causeway. The water improves in quality during its retention in the reservoir as solids settle and organic contaminants are adsorbed and degraded through a combination of natural biological processes aided by sunlight and oxygenation. As well as Oxford and other localities, Farmoor supplies the town of Swindon, some 25 miles (40 km) to the southwest via a trunk main installed in 1986. The reservoir is supplied by water abstracted from the River Thames at a flowrate of about 1.62 m3/s or 140 million litres per day. Water enters the reservoir near the western end of the causeway.