During operations, the upstream mon

During operations, the upstream monitoring facilities and the retention capacities of
the two holding ponds together with the tunnel retention capacity provides the system
operators at least an hour of warning for the need to close the motorway to traffic and
avail it for flood water diversion. Emptying the road tunnel from traffic user will only
take between one hour including closing of the gates and cross passage doors,
conducting a walkthrough check and opening the flood tunnel barrier