The Cloaca Sluices

This shows one of the sluices that controls the outflow of water from the Skymere into the Cloaca. These operate in slots that are cut down into the basalt of the Valley of the Gate. It should be noted that the floor of the Valley is considerably higher than the level of the lake. Each sluice consists of a slab that, when released, resides in a casement that lies lower than the spillway floor. The weight of this sluice is balanced by the counterweights shown. This allows the sluice to be dropped and raised from above by means of cables that, passing over the wooden arch shown, are wound around capstans. Note that there is a sluice at both ends of each slot: at the Skymere end and at the spillway end. Human figures have been added to indicate scale…