Prospective
40 It is a defence to a charge in proceedings under section39(1) for the person to show both—
(a)that the failure to comply with the requirement concerned was as a result of an event which could not reasonably have been foreseen or any natural cause or force majeure which was exceptional and could not reasonably have been foreseen, and
(b)that the person—
(i)took all practicable steps to prevent an uncontrolled release of water from the reservoir,
(ii)took all practicable steps as soon as was reasonably practicable to rectify the failure,
(iii)provided particulars of the failure to the Department as soon as practicable after the failure arose.