Agency may make good the impairment or damage and recover from the Authority the expense  reasonably incurred by it in doing so.  7.  Nothing in paragraphs 4(4), 5(3) and 6 authorises the Agency to execute works on or affecting  the authorised works.  8.  The Authority must indemnify the Agency in respect of all costs, charges and expenses which  the Agency may reasonably incur or have to pay or which it may sustain—  9. —(1) Without affecting the other provisions of this Schedule, the Authority must indemnify  the Agency from all claims, demands, proceedings, costs, damages, expenses or loss, which may  be made or taken against, recovered from, or incurred by, the Agency by reason of—  which is caused by the construction of any of the specified works or any act or omission of the  Authority, its contractors, agents or employees whilst engaged upon the work.  (2) The Agency must give to the Authority reasonable notice of any such claim or demand and  no settlement or compromise may be made without the agreement of the Authority which  agreement must not be unreasonably withheld or delayed.  10.  The fact that any work or thing has been executed or done by the Authority in accordance  with a plan approved or deemed to be approved by the Agency, or to its satisfaction, or in  accordance with any directions or award of an arbitrator, does not relieve the Authority from any  liability under the provisions of this Schedule.  11.  Any dispute arising between the Authority and the Agency under this Schedule, if the parties  agree, is to be determined by arbitration under article 53 (arbitration), but otherwise is to be  determined by the Secretary of State for Environment, Food and Rural Affairs and the Secretary of  State for Transport acting jointly on a reference to them by the Authority or the Agency, after  notice in writing by one to the other.  (a) in the examination or approval of plans under this Schedule; and  (b) in the inspection of the construction of the specified works or any protective works  required by the Agency under this Schedule.  (a) any damage to any drainage work so as to impair its efficiency for the purposes of flood  defence;  (b) any raising or lowering of the water table in land adjoining the authorised works or any  sewers, drains and watercourses;  (c) any flooding or increased flooding of any such lands; or  (d) inadequate water quality in any watercourse or in any groundwater,  75