Open-channel hydraulics is one of the oldest civil building disciplines known to great realm.
When water is confined within a smooth, low-friction channel and subjected to a steep gravity slope, its speed increases according to Torricelli’s law and the Manning equation.
At a speed of thirty-five feet per second, water ceases to behave like a gentle domestic fluid.
It becomes a high-thickness moving battering ram, carrying millions of foot-pounds of high-pressure driving force capable of scouring bedrock and pulverizing timber dams.
Through the four-foot heavy volcanic cement concrete under-road drain of Storm Drainage Conduit Alpha, twenty thousand gallons per minute of white-hot earth-heat blowdown water surged eastward under a hundred and twenty feet of gravity head.
The concrete pipe, lined with glass-fused clay tile to resist heat shock, glowed hot beneath the surface turf.
Along the surface of the eastern fields, frost melted instantly from the grass in a sixty-foot wide swath above the buried channel. That left a steaming green trail through the autumn snow.
Giles Croft stood on the eastern outer edge star-castle wall beside Captain Kenneth Drake, his brass sighting scope trained on the five-acre retention ditch five hundred yards beyond the outer fence.
