[2023] UKUT 201 (LC)

This aspect of the claimant’s case was developed at the hearing rather than in the pleadings or the evidence, and it arose we think from an appreciation in the course of the hearing as a result of Mr Benn’s evidence of the importance of the drop from the concrete weir into the channel. Any water that does not pass beneath the mill is diverted over the concrete weir, and it has to drop to the natural level of the river bed, in this case about a 1.4 metre drop.

The slope, while less sudden than the drop over the wheel, dissipates the energy of the water and is a cause of erosion. Mr Bates therefore suggested to Mr Benn in cross-examination that when carrying out the work in 2001 the Agency should have eliminated, or at least, smoothed out, the slope in order to minimise erosion in the channel.

We regard that as an unrealistic suggestion. It was not supported by expert evidence from Dr Brookes and was not an option that he considered. Mr Benn dismissed it as a practical possibility in 2001; if the slope had been somehow evened out (perhaps over the length of reach 7a) Mr Gould’s garden would have repeatedly flooded because the bed of the channel would have been higher for some of its length. What actually happened was, as Mr Willis said, that the Agency’s team matched the slope they found. The purpose of the installation of the gabion was to absorb the energy as the water dropped down the slope; and it is easy to see how that happens as some of the water is going to fall through the gaps between the stones within the gabion so that the force of the flow is dissipated.

We accept the evidence of Mr Benn and Mr Willis that there the Agency matched the slope it found, and we do not accept the argument that it was incorrect to do so or that the drop to the natural river level could somehow have been eliminated.