Mile Two of the Causeway was where the delta showed its teeth.
Here, the ancient, underwater stone highway crossed the mouth of the Old Sluice Creek. A deep, fast-flowing tidal channel that drained twenty thousand acres of salty salt-pans into the open estuary. Sixty years ago, royal masons had spanned the creek with a low, three-arch stone under-road drain, designed to let the tidal currents rush beneath the roadbed while heavy freight wagons rolled across the top in safety.
Now, as Tomas, Nessa, and Sile approached the crossing, the under-road drain was invisible beneath four feet of swirling, frothing gray salt water.
The tide was running out with the speed of a mill-race. The water, forced through the narrow gap between the underwater stone abutments, formed a violent, sucking vortex. A high-pressure drain tube that roared with a low, underground rumble that shook through the mud beneath their boots. Yellow foam and torn ribbons of marsh grass spun in circles on the surface before being sucked down into the dark, churning depths.
Tomas stopped on the edge of the underwater bridge pillar, the water lapping against the tops of his thigh boots. He unslung his ash pack frame, setting it on a relatively dry patch of gravel.
“The bridge didn’t collapse,” Nessa said, her brass sound horn held to her right ear, pointed directly at the foaming water. She listened with her head tilted. Her eyes tracked the surface whirlpools with the analytical calm distance of a physician listening to a diseased chest. “Listen to the tone. It isn’t a broken clouded eye. The pitch is low and ringing—about ninety shakes a second. That’s the sound of water being forced through a restricted orifice under water-pressure head. The three stone arches are still down there. They’re choked.”
“Choked with what?” Sile asked, planting his hooked pruning blade firmly into the gravel.
“Driftwood, dead willow trunks, and scrap timber,” Tomas replied. He pointed to the edge of the vortex. “The trade ring hasn’t cleared the trash racks in twenty years. The debris has created a dam. That forced the tidal current to wash over the roadbed instead of through the under-road drains.”
“If we want to survey the roadbed across the gap, someone has to wade the drain tube,” Nessa said. Her gaze turned to Tomas, her gray eyes unblinking. “The rod has to be held on the central crown of the middle arch. If the stonework has washed out in the center, the whole raised stone road is broken.”
Tomas didn’t hesitate. He sat on an exposed dark rock curb stone, checking the straps of his boots. He took a thirty-fathom coil of three-strand manila hemp from his pack, uncoiling the stiff, tarred line onto the gravel.
“Sile, take the snubbing turn around that dark rock bollard,” Tomas directed, tying a heavy bowline knot around his chest, passing the rope under his armpits. “Give me twenty feet of slack. If the current takes my feet, don’t haul right away. Snub the rope and let my body swing into the lee eddy on the left.”
“I have the rope, Tomas,” Sile said, his huge, scarred hands wrapping twice around the hemp. He braced his boots against the dark rock curb, his back locked like an oak post. “Watch the undertow. Drain tube water pulls downward, not sideways.”
Tomas tested the hemp rope around his chest once more, checking the knot with his fingers. The three-strand manila was rough, hairy, and smelled sharply of pine tar and vegetable oil. Even through his thick wool tunic, the coarse fibers bit into his ribs. Just then, he leaned his weight into the line. Rope burn was the cart driver’s trade-mark. He had seen old porters whose chest and shoulder skin was as thick and hairless as cured sole leather from twenty years of hauling canal boats.
“If the line fouls on an underwater root, Sile,” Tomas said, his voice quiet against the roar of the water, “don’t haul on the standing part. Cut the snubbing turn and let the line run free through the eye-hook. I have my folding knife in my right vest pocket. I can sever the bowline in two strokes if I get dragged under.”
Sile nodded, his face impassive as granite. “The line won’t foul. I dressed the thick ship rope with sheep fat this morning. It will slide through a timber knot like an eel through wet grass.”
Tomas stepped into the current.
The force of the rushing salt water struck his knees like an iron battering ram. The water was freezing—barely forty degrees—and heavy with dissolved salt and gritty delta sand that scoured against his cowhide boots with a harsh, hissing friction. He leaned his upper body forward at a thirty-degree angle. He drove his ash-wood staff deep into the crevices between the underwater dark rock slabs before moving his feet.
With every step, the water rose: from mid-thigh to his hips, from his hips to the bottom of his leather courier satchel.
As Tomas waded deeper into the drain tube, the shaking through his boots became ear-splitting. It wasn’t sound heard through the ears. But a deep, high-pressure thrumming that rang in the marrow of his shin bones. Thousands of tons of salty marsh water being tightly packed into a twelve-foot gap beneath the roadbed. The water tasted sharply of salt and bitter iron ore, spraying up in fine, freezing droplets that coated his eyelashes in salt frost.
He drove his ash staff down into the gap between two dark rock slabs. He felt the stone resist with total solidity. Royal volcanic cement mortar—fiery ash mixed with wet lime plaster and seawater—didn’t soften under water. It hardened over decades, becoming harder than the dark rock itself.
“The foundation is sound!” Tomas bellowed through the spray. “The arches are taking forty thousand pounds of deep water pressure and they aren’t weeping a grain of sand!”
At the center of the breach, twelve paces out from the bridge pillar, the water reached his chest.
The deep water pressure was terrifying. Thousands of tons of delta water, draining from the vast marsh pool behind him, surged against his ribs, compressing his lungs until every breath was a sharp, painful effort. The current tore at his boots, trying to lift his heels from the stone and sweep him into the churning mouth of the drowned under-road drain. In his left forearm, the gristle of his scar ached with a dull, throbbing numbness from the freezing salt water. But his right arm locked around his staff, wedging the iron metal ring into a stone joint.
“Hold!” Nessa shouted from the bank.
She stood on the stone bridge pillar, sighting through her brass transit. Apprentice Olla stood beside her, holding the zinc recording slate, her face pale with anxiety.
“I need the depth on the central crown!” Nessa called out, her voice cutting through the roar of the water.
Tomas reached down with his right hand, pulling his brass sounding rod from his belt. He drove the weighted tip down between his boots until it struck the stone beneath the mud.
CLINK.
He read the brass depth ring with his fingers, feeling the raised notches beneath the murky water.
“Four feet two inches!” Tomas shouted back against the wind. “Stone is level! Mortar is intact!”
He moved his fingers along the edge of the slab.
“The low roof wall is gone!” he yelled. “The trade ring knocked down the protective stonework so carts couldn’t cross on the high tide! But the roadbed—the roadbed is solid rock!”
Suddenly, his left boot shifted.
An underwater willow log, swept along by the violent undercurrent, struck his left calf with the force of a swinging club. His foot slipped from the stone joint, the suction of the vortex catching his legs. He pulled his lower body out from under him.
Tomas fell into the rushing water.
The icy salt water closed over his head with an ear-splitting roar. The current dragged him toward the drowned mouth of the middle arch, where water was roaring through a three-foot gap between tangled tree trunks.
On the bank, Sile Rook’s muscles bunched.
The veteran didn’t shout. He dropped his weight onto his rear heel. His calloused hands locked around the three-strand hemp rope as the tension came onto the line with a sharp, violent snap that squeezed water from the braided fibers. The manila rope smoked across the corner of the dark rock bollard, groaning under the strain of four hundred pounds of dynamic high-pressure pull.
Sile held. His keloid burn scars pulled taut across his ribs, his breath whistling through his teeth, but his boots didn’t slip an inch.
The rope pulled taut, arresting Tomas’s descent six feet from the vortex mouth.
Tomas surfaced, coughing out mouthfuls of bitter, stinging salt water. He caught the taut hemp rope with his right hand, finding purchase with his boots against an underwater timber strut. He levered himself upward, dragging his chest back onto the crown of the dark rock roadbed.
He stood up, coughing, water streaming from his hair, his woolen clothes clinging to his shivering frame like sheets of lead.
On the bank, Nessa lowered her sighting transit. Her face was pale, but her hands were steady as she marked the height on Olla’s slate.
“Mile Two surveyed,” Nessa called out, her voice flat and unshaken. “Roadbed intact. Clearance needs removing the trash dam at low tide. Get back to the bank, Tomas. You’re turning blue.”
Tomas wiped the salt from his eyes with his numb fingers, grasped the guide rope, and hauled himself hand-over-hand back toward the dry shell ridge.