12.—(1) The authorised development must not be commenced until a construction surface water drainage scheme for the authorised development has been submitted to and approved in writing by the relevant planning authority in consultation with the Environment Agency.
(2) In accordance with chapter 13 of the environmental statement, the approved construction surface water drainage scheme must include—
(a)a construction site drainage plan; and
(b)a construction sediment management plan.
(3) The construction site drainage plan mentioned in paragraph (2) must stipulate measures to ensure that flood risk is managed on the land within the Order limits and to prevent the unacceptable increase of the flood risk elsewhere. The plan must include—
(a)measures to ensure that all discharge rates to neighbouring watercourses will be restricted to existing greenfield runoff rates unless otherwise agreed by the relevant planning authority in consultation with the lead local flood authority;
(b)details of the drainage measures to be provided during the construction period to manage flood risk; and
(c)details of the timescales for carrying out the measures in the scheme.
(4) The construction sediment management plan mentioned in paragraph (2) must stipulate measures for the management of sediments suspended in or otherwise transported by runoff originating from construction of the authorised development. The plan must include details of pollution prevention measures that will be taken to protect ground and surface water quality.
(5) The works required by the approved construction surface water drainage scheme must be completed in accordance with the timescales specified in the scheme and (where required by the scheme) implemented throughout construction of the authorised development.