An engineer appointed for the purposes of this section shall be appointed to inspect the reservoir and make a report on the construction or alteration, and to supervise the reservoir until he gives a final certificate for the reservoir under this section.

An engineer acting under this section shall include in his report any recommendations he sees fit to make as to measures to be taken in the interests of safety; and, subject to any reference of the matter to a referee in accordance with this Act, the undertakers shall carry any such recommendation into effect F5within the period which the report must specify in respect of each recommendation.

Where it appears to the enforcement authority that the report of an engineer acting under this section includes a recommendation as to measures to be taken in the interests of safety that has not been carried into effect as required by this section, the authority may by written notice served on the undertakers require them to carry the recommendation into effect within a time specified in the notice.

Where an enforcement authority propose to serve such a notice, the authority shall consult as to the time to be specified in the notice a civil engineer, being a qualified civil engineer for the purpose of inspecting and supervising the reservoir under this section.

Except as provided by subsections (5) and (6) below, an engineer acting under this section shall have the same powers and duties in relation to the giving of preliminary certificates, interim certificates and final certificates as if he were the construction engineer responsible for the reservoir or, as the case may be, the F6alteration to it; and certificates under this subsection shall have effect for purposes of this Act as if they were certificates of a construction engineer.

A final certificate under this section may be given less than three years after the first issue of a preliminary certificate, or without the previous issue of a preliminary certificate, if the engineer is satisfied that the reservoir F7... has for a period of three years or more been filled with water up to the level that is specified in the preliminary certificate or, if no preliminary certificate has been issued, up to the level that is specified in the final certificate, and that the reservoir F8... is sound and satisfactory and may safely be used for the storage of water.

A final certificate under this section, other than one given by virtue of subsection (5) above, shall not be required to state that the engineer is satisfied the reservoir F9... is sound and satisfactory; but, if it does not do so and the engineer’s report includes any recommendations as to measures to be taken in the interests of safety, the certificate shall instead state that those recommendations have been carried into effect.

In addition to certificates under subsection (4) above, an engineer acting under this section, shall, as soon as practicable after the completion of the works and in any event not later than the giving of the final certificate, give a certificate that, so far as he has been able to ascertain, the works have been efficiently executed in accordance with the drawings and descriptions annexed to the certificate, and shall annex to the certificate detailed drawings and descriptions giving such information as he can of the works actually constructed, including dimensions and levels and details of the geological strata or deposits encountered in trial holes or excavations made in connection with the works

References in this Act to a final certificate under this section or to a certificate under subsection (7) above include the annex to the certificate, where there is one.