 The Metropolitan Water Board operated the reservoir until the Board was abolished in 1974 under the provisions of the "Water Act 1973" (c. 37) and ownership and control transferred to the Thames Water Authority.Under the provisions of the Water Act 1989 (c. 15) the Thames Water Authority was privatised as Thames Water.The reservoir was formed by the construction of a continuous embankment on the floodplain of the River Lea at Chingford.