It shall be the duty of the Agency to take all such action as it may from time to time consider, in accordance (if any have been given for the purposes of this section) with the directions of the Secretary of State, to be necessary or expedient for the purpose—
of conserving, redistributing or otherwise augmenting water resources in England and Wales; and
of securing the proper use of water resources in England and Wales.
Nothing in this section shall be construed as relieving any water undertaker of the obligation to develop water resources for the purpose of performing any duty imposed on it by virtue of section 37 of the Water Industry Act 1991 (general duty to maintain water supply system).