Water Management (General) Regulation 2018
Current version for 1 July 2020 to date (accessed 7 July 2020 at 16:56)
50   Exemption relating to certain earthworks
A person is exempt from section 91D(1) of the Act if—
(a)  the person constructs or uses a flood work that consists of earthworks (including farm tracks and check banks) that are less than 150 millimetres above (but not below) the natural surface of the ground in or on which it is constructed or situated, and
(b)  the work is not situated in or on a place that is located within a designated high risk flood area.