I guess that explains the design of some of the "water level" bridges we crossed. There's nothing to wash out.
That's how I interpreted it, looking at those water level markers showing how many feet above the road surface the water could be expected to rise... 5 to 9 feet, depending on the crossing!
Keith the road engineer oughta be able to e'splain it to us, Lucy.
"I'm gonna have to science the schit out of this." Mark Watney, Sol 59, Mars
