Lecture Notes on Hydrology

Vocabulary flashcards for hydrology terms based on lecture notes.

Baseflow

Background low-flow conditions in a stream.

Capillary Barriers

Coarse layers of sediments that impede the movement of water under unsaturated conditions.

Hysteresis

Loop-like curve, relates pairs of hydraulic properties of an unsaturated porous medium because volumetric moisture content, capillary-pressure head, and hydraulic conductivity covary along different curves depending on whether the soil is absorbing or draining water.

Infiltration-Excess Overland Flow/Hortonian overland flow

Mechanism of runoff generation where the infiltration capacity of a catchment is exceeded by rainfall intensity, resulting in ponding and surface flow.

Macropores

A relatively large pore in fine-grained soil, such as a soil pipe, animal burrow, or shrinkage crack.

Quickflow

One of two components into which a flood hydrograph can be separated (the other is known as baseflow).

Richard’s Equation

Expression of mass conservation in the unsaturated zone, incorporating Darcy’s law. Solutions provide a history of the pressure distribution in a vertical soil column.

Saturation Excess Overland Flow

Mechanism of runoff generation, important in humid regions where a shallow water table intersects the ground surface, causing ponding and surface flow.

Shallow Subsurface Stormflow

A mechanism of runoff generation where water flows through a shallow, permeable soil horizon,; some of the flow may occur along preferred pathways known as macropores

Soil Horizon

A soil layer defined based on the history of its formation, physical, and chemical properties.

Tensiometer

A device for measuring negative capillary-pressure heads in soils.

Variable Contributing Area Concept

The idea that catchment areas where saturation-excess overland flow develops expand and contract with time over a storm.