11.—(1) The construction of a dam or reservoir is within regulation 3(1)(h) only if the volume of water to be held back by the dam or stored in the reservoir is expected to exceed 10 million cubic metres.
(2) The alteration of a dam or reservoir is within regulation 3(1)(h) only if the additional volume of water to be held back by the dam or stored in the reservoir as a result of the alteration is expected to exceed 10 million cubic metres.