Parts of the towns of Windsor, Eton and Maidenhead are prone to flooding, because they are built on the flood plain of the River Thames. The concept of a parallel channel which could take water from the Thames above Maidenhead and return it below Windsor was conceived in the 1980s, and became known as the Maidenhead, Windsor and Eton Flood Alleviation Scheme. When the ten regional water authorities were privatised, as a result of the Water Act 1989, responsibility for rivers passed to the National Rivers Authority, which soon afterwards submitted plans for a channel which would be wide and long. In October 1992 a planning enquiry was held to consider the proposals. During that enquiry, P. Ackers, one of the assessors, expressed grave doubts about the hydraulic modelling that had been used to justify the scheme, suggesting that it was too optimistic.