Glossary of Terms - Rainfall-Runoff Modelling: The Primer - page 386

Uniform Flow An open channel flow or overland flow in which the slope of the water surface is equal
to the bed slope such that energy loss due to frictional shear stress is exactly matched by the potential
energy gain as the water moves downhill [Section 5.2; Box 5.6]
Unit Hydrograph The “storm runoff” response from a unit of “effective rainfall” [Sections 2.2,
2.3, 4.3]
Validation A process of evaluation of models to confirm that they are acceptable representations of a
system. Philosphers of science have some problems with the concept of validation (see Section 1.8)
and it may be better to use “evaluation” or “confirmation” rather than “validation” (which, from its
Latin root, implies a degree of truth in the model) [Sections 1.8, 5.3, 10.5]
Vector Digital ElevationModel A set of irregularly spaced elevation points defining contours of equal
elevation [Section 3.7]
Wave speed see Celerity.