River flood prevention by assisted water flow involves placing polymer sheet on river bed in roll form in autumn so inbuilt stiffeners and push-rods flatten sheet out in spring to even out river bed for unobstructed onward flow.

摘要

A polymer sheet is laid on the river bed so as to even the bed out, one sheet with and one without inbuilt stiffeners and push-rods to unroll the sheet. The sheet is anchored to the river bed and can be installed in the autumn still rolled up so that the sheet rolls out in the thaw with the accelerated water flow, even without the use of pumps.