..., where any ordinary watercourse is in such a condition that the proper flow of water is impeded, then, unless the condition is attributable to subsidence due to mining operations (including brine pumping), the drainage board ... concerned may, by notice served on a person falling within subsection (3) below, require that person to remedy that condition.
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Subject to subsection (4) below, a notice under this section in relation to a watercourse may be served on—
No notice under this section requiring any person to carry out any work on land not owned or occupied by him shall be served without the consent of the owner and the occupier of the land, except in a case where it is not practicable, after reasonable inquiry, to ascertain the name and address of the owner or occupier.
A notice under this section shall indicate—
Subject to the right of appeal provided by section 27 below, if the person upon whom a notice is served under this section fails to carry out the works indicated by the notice within the period so indicated—
In proceedings by the drainage board ... concerned for the recovery of any expenses under subsection (6) above it shall not be open to the defendant to raise any question which he could not have raised on an appeal under section 27 below.
Nothing in this section shall affect the right of an owner or occupier to recover from the other, under the terms of any lease or other contract, the amount of any expenses incurred by him under this section or recovered from him by the drainage board ... concerned.