Paragraph 16 Obstruction in the riverI1

If any pile, stump or other obstruction to navigation becomes exposed as a result of constructing any tidal work (other than a pile, stump or other obstruction on the site of a structure comprised in any permanent work), the undertaker shall, as soon as reasonably practicable after the receipt of notice in writing from the Authority requiring such action, remove it from the river or, if it is not reasonably practicable to remove it—

If after such reasonable period as may be specified in a notice under this paragraph the undertaker has failed to begin taking steps to comply with the requirements of the notice, or after beginning has failed to make reasonably expeditious progress towards their implementation, the Authority may carry out the works specified in the notice and any expenditure reasonably incurred by it in so doing shall be recoverable from the undertaker.