(1)The restriction on abstraction shall not apply to any abstraction of water from a source of supply in the course of, or resulting from, any operations for purposes of land drainage.
(2)The restriction on abstraction shall not apply to any abstraction of water from a source of supply in so far as the abstraction (where it does not fall within subsection (1) above) is necessary—
(a)to prevent interference with any mining, quarrying, engineering, building or other operations (whether underground or on the surface); or
(b)to prevent damage to works resulting from any such operations.
(3)Where—
(a)water is abstracted, in the course of any such operations as are mentioned in subsection (2) above, from any excavation into underground strata in a case in which the level of water in the underground strata depends wholly or mainly on water entering it from those strata; and
(b)the abstraction is necessary as mentioned in that subsection,
the exemption conferred by that subsection shall apply notwithstanding that the water is used for the purposes of the operations.
(4)In the case of any abstraction of water from underground strata which falls within subsection (1) or (2) above, the restriction imposed by section 24(2) above shall not apply—
(a)to the construction or extension of any well, borehole or other work; or
(b)to the installation or modification of machinery or other apparatus,
if the well, borehole or other work is constructed or extended, or the machinery or apparatus is installed or modified, for the purpose of abstracting the water.
(5)In this section, “land drainage” includes the protection of land against erosion or encroachment by water, whether from inland waters or from the sea, and also includes warping and irrigation other than spray irrigation.