The four-foot spoked wheel of Sluice Gate Four was crusted with twelve years of hardened copper scale and hardened river silt. Nessa and Hollis threw their weight against the bronze rim. Then, the metal shrieked with the painful friction of dry gears binding in their housings.
“HEAVE!” Nessa cried out, her boots slipping on the slimy iron grating as the muscles of her back strained against her coarse flannel shirt. “Take the spokes together, Hollis! Don’t let the dog catch!”
Hollis swung the eight-pound sledge with all his strength, striking the bronze locking wedge with an ear-splitting ring. The wedge jumped three inches from its taper seat, spitting sparks across the wet floor. With the locking dog freed, the massive balance weight inside the upright wall shaft dropped four feet with a heavy, air-powered thud into its oil-filled dashpot.
The bronze gate, nine inches thick and weighing four thousand pounds, lifted from its granite doorstep.
Behind the bronze plate, fifty thousand cubic feet of tightly packed river water had been held in water-pressure holding. It was backed by the full high-pressure head of the upper pool. The moment the seal broke, the water didn’t merely flow. It erupted with the bone-shaking violence of an artillery blast. A geyser of black, boiling river sludge and sulfur foam burst through the intake water chute, roaring through the underground tunnels at forty miles an hour, shaking the entire foundation vault until lime dust fell like snow from the brick ceiling arches.
