Derwent Reservoir

The Derwent Reservoir lies on the River Derwent, straddling the border between County Durham and Northumberland. It stretches 3.5 miles long and covers 4 square kilometres, with a maximum depth of 30 metres. The water body holds 50 million cubic metres when full, making it a major feature in the landscape. Princess Alexandra opened the reservoir in July 1967 after construction began in 1960. Unlike many northern reservoirs, it was excavated rather than formed by flooding a valley. The reservoir supplies 130 million litres of water daily to the Tyne and Wear area. Water can be transferred from Kielder Water when needed, though this does not increase the reservoir’s depth. Elevated levels of zinc, lead and cadmium have been detected in the sediment, linked to historic mining near Blanchland. These metals have reduced the growth of macroscopic plants in the water. Despite this, the reservoir supports a sailing club that organises windsurfing, sailing and triathlons throughout the year. Around the reservoir, the annual Tour of the Reservoir cycle race takes place. A small hydroelectric plant operates here with a capacity of 97 kilowatts. The surrounding area offers open space for walking and observing the water. The reservoir’s dam head was built using earth excavated during its creation. Its role in water supply and local events makes it a notable site in the region.