Friday, May 06, 2022 at 06:41
Hello
John,
The tunnel cuts directly through under Watsons Crags (spur), on the
Lady Northcote side it has a aqueduct (buried pipe line) entering from the side of a bulkhead, this bulkhead has "stop logs" to make the collected water run through to the Siren Song intake thus ends up in
Geehi Dam via a buried pipe line. This known as the "
Geehi River Aqueduct". The tunnel runs water all of the time but the level is dependent on weather conditions (runoff).
People have been know to walk through the tunnel whilst flows are low but this would be risky?!? The only time the tunnel is not running water is when the an outage for maintenance, usually in late Summer early Autumn, which means the intakes are "turned out" (creeks returned to their original beds) and the tunnel is drained thus the above mentioned "stop Logs" are removed to allow vehicular access through the tunnel to the Opera House and the intakes on that side. Please note that this all behind locked gates, and the tunnel is 95% bare
rock 2.3-4 Km's through and water levels can rise very quickly from localised storms on the main range.
Cheers
FollowupID:
919499