Originally Posted by
ShyTorque
I overheard an interesting conversation last night in a restaurant (I admit I cannot verify what was said so it's definitely rumour only).The gist of it was that dams like this were built with side spill outlets controlled by valves. These are meant to be used to control the maximum water level, to prevent over-topping of the wall but unfortunately these valves could no longer be opened at this dam, because the mechanism has rusted solid over many years.
What you overheard was absolute nonsense. The current pictures clearly show the weir at the top of the spillway. This controls the maximum level, no valves involved. Outlet valves will be at the bottom, possibly in a tunnel within the dam. These will be in regular use to control the flow from the reservoir, and will be maintained in good working order, certainly not allowed to "rust solid over many years".