High Quality Content by WIKIPEDIA articles! Kielder Water is a large artificial reservoir in Northumberland in North East England. It is the largest artificial lake in the United Kingdom by capacity and it is surrounded by Kielder Forest, the largest human-made woodland in Europe. It was planned in the late 1960s to satisfy an expected rise in demand for water to support a booming UK industrial economy. It was constructed between 1975 and 1981 by an AMEC/Balfour Beatty joint venture and was opened by Queen Elizabeth II in 1982. It took two years for the valley to fill with water completely once construction was completed.