The Reservoirs (Scotland) Regulations 2015

Calculation of volume of water that a structure or area is capable of holding

3.—(1) For the purposes of Part 1 of the Act, the volume of water that a structure, loch or other area referred to in paragraph (a) or (b) of section 1(2) of the Act (“the reservoir”) is capable of holding above the natural level of any part of the surrounding land is to be calculated by measuring the maximum volume of water (in cubic metres) which is capable of being held in the reservoir—

(a) above the bed of the reservoir; and

(b) between the toe of the reservoir and its top water level.

(2) Water not capable of flowing out of the reservoir over natural ground in the event of an uncontrolled release (of water from the reservoir) must not be included in the calculation.

(3) In paragraph (1)—

“bed”, in relation to a reservoir, includes any silt or other material that is incapable of flowing out of the reservoir over natural ground in the event of an uncontrolled release of water from the reservoir;

“toe” means the point on the downstream side of a dam, reservoir wall or embankment forming part of the reservoir where the base of the dam, reservoir wall or, as the case may be, embankment meets the lowest level of the natural ground (which remains after the construction, or any alteration, of the reservoir) of any part of the land adjacent to the reservoir, including the lowest bed level of any watercourse; and

“top water level” means—

(a)

in the case of a reservoir with a fixed overflow sill, the lowest crest level of that sill;

(b)

in the case of a reservoir the overflow from which is controlled wholly or partly by moveable gates, syphons or otherwise, the maximum level to which water may be held exclusive of any provision for flood storage; or

(c)

in the case of a reservoir designed for the purposes of holding back floodwater, the maximum level to which floodwater may be held during any flood event exclusive of any provision for overflow.