3. Without prejudice to the generality of paragraph 2 but subject always to the provision of that paragraph as to reasonableness, the requirements which the Agency may make under that paragraph include conditions requiring the undertaker at its own expense to construct such protective works, whether temporary or permanent, before or during the construction of the specified works (including the provision of flood banks, walls or embankments or other new works and the strengthening, repair or renewal of existing banks, walls or embankments) as are reasonably necessary—
(a)to safeguard any drainage work against damage; or
(b)to secure that its efficiency for flood defence purposes is not impaired and that the risk of flooding is not otherwise increased,
by reason of any specified work.