I can show you fields which have stone cage embankents that were keeping a river on a certain course.

The only snag is the river is no longer anywhere near them.

It is interfering with the natural flow of a river which causes much flooding, floods in the lower Severn come from water in the upper river.

Mess about with the upper Severn and it will make matters worse, hold back that water with flood plains etc, and flooding will be reduced.

Plus as I said, getting rid of the water as quickly as possible leads to summer droughts.