Hydrology Exam 4 (Final Exam)

Front 1

Hysteresis

Back 1

the loop-like curve that 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 imbibing water or draining

Front 2

Soil Horizon

Back 2

a layer of soil defined on the basis of physical and chemical properties and on the history of its formation

Front 3

Macropores

Back 3

a relatively large pore, such as a soil pipe, animal burrow, or shrinkage crack, in an otherwise fine grained soil

Front 4

Capillary barriers

Back 4

coarse layers of sediments that impede the movement of water under unsaturated conditions

Front 5

Quickflow

Back 5

one of the two components into which a flood hydrograph can be separated

Front 6

Baseflow

Back 6

background low-flow conditions in a stream

Front 7

Infiltration-excess overland flow

(also known as Hortonian overland flow)

Back 7

a mechanism of runoff generation in which the infiltration capacity of a catchment or portion of a catchment is exceeded by the rainfall intensity, which results in ponding of precipitation at the soil surface and flow across the surface either in sheets or small rivulets

Front 8

Saturation-excess overland flow

Back 8

a mechanism of runoff generation that is particularly important in vegetated catchments in humid regions in which a shallow water table intersects the ground surface, causing ponding of water at the soil surface and flow across the surface either in sheets or small rivulets

Front 9

Variable contributing area concept

Back 9

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

Front 10

Shallow subsurface stormflow

Back 10

a mechanism of runoff generation whereby water flows through a shallow, permeable soil horizon, such as when a perched water table forms above a layer of the soil with low permeability; some of the flow may occur along preferred pathways known as macropores

Front 11

Return flow

Back 11

the process by which groundwater reemerges from the soil at a saturated area and flows down slope as overland flow

Front 12

TOPMODEL

Back 12

a hydrological catchment model based on land-surface topography

Front 13

Topographic index

Back 13

TI=ln(a/tanB), where a is the upslope contributing area per contour length and tanB is the local slope; used by the catchment model TOPMODEL to calculate the water balance for individual blocks within a catchment