23.—(1) Network Rail must take all such measures as may be reasonably practicable to prevent any interruption of the free passage of fish in the fishery during the construction of any specified work.
(2) If by reason of—
(a)the construction of any specified work; or
(b)the failure of any such work,
damage to the fishery is caused, or the Agency has reason to expect that such damage may be caused, the drainage authority may serve notice on Network Rail requiring it to take such steps as may be reasonably practicable to make good the damage, or, as the case may be, to protect the fishery against such damage.
(3) Subject to paragraph 24, if within such time as may be reasonably practicable for that purpose after the receipt of written notice from the Agency of any damage or expected damage to the fishery, Network Rail fails to take such steps as are described in sub-paragraph (2), the drainage authority may take those steps and may recover from Network Rail the expense reasonably incurred by it in doing so.
(4) Subject to paragraph 24, in any case where immediate action by the Agency is reasonably required in order to secure that the risk of damage to the fishery is avoided or reduced, the drainage authority may take such steps as are reasonable for the purpose, and may recover from Network Rail the reasonable cost of so doing provided that notice specifying those steps is served on Network Rail as soon as reasonably practicable after the Agency has taken, or commenced to take, the steps specified in the notice.