A threat to land values along the course of the Manchester Ship Canal has been lifted by a Court of Appeal ruling that sluices that have regulated the waterway’s flow for more than a century were wrongly classified as formal flood defences by the Environment Agency (EA).
The EA’s decision to place substantial tracts of land adjoining the canal within Flood Zone 3 – denoting a 1% annual chance of flooding – had caused outrage amongst land owners. The local planning authority had proposed allocating land on Pomona Island, Trafford, for construction of 1,500 new homes but reduced that to 800 in the light of the EA’s stance.
Peel Holdings (Land and Property) Limited – the company behind the Pomona Island proposals and which owns more than 300 acres in the area - and The Manchester Ship Canal Company Ltd, which is part of the same group, sought judicial review of the agency's decision.
The EA argued that it had consistently followed its national policy of assessing flood risks on the basis that existing flood defences will fail and thus should be left out of account. However, the companies’ successfully argued at first instance that the canal’s sluices could not rationally be viewed as formal flood defences.
In dismissing the EA’ s appeal, the court noted that, since the canal’s completion in 1894, the sluices had never failed to drain a total catchment area of 3,000 square kilometres in the Manchester and Warrington areas which had previously been prone to flooding. The companies had relied upon evidence that the chance of the sluices failing in a 1% probability flood was less than 0.01%.
The court acknowledged that the sluices performed a vital role in preventing ‘over-topping’ of the canal's banks during high floods. However, in classifying them as flood defences, the EA failed to follow its own published policy or to recognise that the sluices had an equally significant role in achieving the canal's primary purpose.
The court concluded: "It makes no sense to describe the canal as a formal flood defence: it is designed and operates so as to permit sea-going ships to be navigated inland. The operation of the sluices is integral to the operation of the canal. The sluices and their associated locks enable the canal to achieve this purpose. It makes no more sense to describe the sluices as flood defences than the canal itself.
"The mere fact that the canal controls and regulates the flow of water cannot be a basis for placing either the canal or its associated structures within the category of formal flood defence. In short...either the whole of the canal and the structures by which it is operated are formal flood defences or none of them are".