drainageDatum

The level the drainage runs down to, meters: the sea where there is one, and the lowlands where there is not.

A valley has to shallow toward something, or every channel on a body is a canyon of the same depth at the coast as on the plateau. On a dry world with liquid — rivers that end in basins and lakes — the datum is set below the swell's own range, so the whole surface drains toward its lowest ground and the channels there are dry beds at the floor's own level.

surfaceSurfaceParameters

Undocumented