The valve tower and overflow weir at Pontsticill Reservoir

The valve tower and overflow weir at Pontsticill Reservoir is a castle, fort or tower in Merthyr Tydfil, Wales. Perhaps water climbed the tower like a living thing, waiting for the valve to open and send it spilling across the weir. Maybe the structure was built to hold back more than rain, as if the reservoir itself needed a guard. Imagine standing at the base when the water rose, listening for the clang of the valve and watching the overflow turn the land into a river.