[2023] UKUT 201 (LC)

This is an important element of Mr Gould’s case. A change in the “accustomed flow” of water beneath a mill is in itself a tort (private nuisance) so that, even if no fault can be found with the 2001 works in themselves, if Mr Gould can show that since 2001 the flow has been changed then he can succeed in his claim.

In the absence of measurements of the flow taken at a number of times of the year before the installation of the side weir and in a range of conditions, it is difficult to assess whether the flow has changed. Dr Brookes’ opinion was that it has, for a number of reasons. One reason was the evidence of maps, which he said show that there was no water passing over the earth weir into the side channel before the concrete weir was built. Second, he said that much more water flows over the side weir than under the mill, on the basis of measurements he has taken and on the basis of observations at the site. Third he said that no erosion occurred in the channel prior to 2001 and that the erosion that has occurred since is more than normal for this stretch of river, which must itself show that the flow has been altered.