by reason of any dam, weir or sluice holding back the waters and does so by causing the deposit to be carried away in suspension in the waters; or (b) any substantial amount of vegetation cut or uprooted in any inland waters, or so near to any such waters that it falls into it, is allowed to remain in the waters by the wilful default of any person, then, subject to the following subsection, that person shall be guilty of an offence and liable on summary conviction to a fine not exceeding level 4 on the standard scale. (2) Nothing in paragraph (a) of the preceding subsection applies to anything done in the exercise of statutory powers conferred by or under any enactment relating to land drainage, flood prevention or navigation. (3) Regulations may provide that any reference to inland waters in subsection (1) of this section shall be construed as including a reference to such coastal waters as are prescribed for the purposes of that subsection. (4) Any question as to whether the consent of [ F242 SEPA ] in pursuance of subsection (1) of this section is unreasonably withheld shall be determined by the Secretary of State; and any consent given in pursuance of section 24 of the Rivers (Prevention of Pollution) (Scotland) Act M43 1951 (which is superseded by this section) shall be treated for the purposes of this section as given in pursuance of this section. [ F243 (5) This section is subject to section 114