Paragraph 23 I1

If by reason of the construction of a specified work or of the failure of F1... a specified work the efficiency of any drainage work for flood defence purposes or land drainage is impaired, or that drainage work is otherwise damaged, the impairment or damage must be made good by the undertaker as soon as reasonably practicable to the reasonable satisfaction of the drainage authority and, if the undertaker fails to do so, the drainage authority may make good the impairment or damage and recover from the undertaker the expense reasonably incurred by it in doing so.