This section applies where a water-course forms a boundary line between two or more local government areas.

If, in the exercise of any power conferred by the Water Resources Act 1991 (c. 57), the Land Drainage Act 1991 (c. 59) or any other enactment, the water-course is altered in any way which affects its character as a boundary line, the person under whose authority the alteration is made must as soon as reasonably practicable give the Welsh Ministers notice of the alteration.

The Welsh Ministers may, by order, vary a boundary line to which a notice given under subsection (2) relates by substituting a new boundary line (whether or not consisting wholly or in part of the line of the water-course as altered) for so much of that boundary line as, before the alteration, lay along the line of the water-course.

The Welsh Ministers must consult the Commission before making an order under subsection (3).

The Welsh Ministers must, in such manner as they consider appropriate, publish notice of any order made under this section.

For the purposes of this section, a reference to local government area includes a reference to a preserved county.