Hydrology Vocab

Vocab

Velocity

rapidity of motion or operation; swiftness; speed

Discharge

the volume of water moving down a stream or river per unit of time

Head

the source of a river

Mouth

where a river flows into a larger body of water

Gradient

the slope of the stream's channel, or rise over run.

Tributary

a river or stream flowing into a larger river or lake.

Trunk Stream

the primary downstream segment of a river, as contrasted to its tributaries

River System

a river and its tributaries

Watershed/Drainage Basin

the ridge or crest line dividing two drainage areas; water parting; divide.

Divides

the line or zone of higher ground between two adjacent streams or drainage basins.

Erosion

the process by which the surface of the earth is worn away by the action of water, glaciers, winds, waves, etc.

Deposition

The settling of sediment in a river.

Transportation

rivers carrying their load downstream

Bed Load

the discharge of sediment particles which are too heavy to be suspended by the turbulent action of the flow

Saltation

a form of transport for sediment in rivers

Suspended Load

part of the total sediment transport which is maintained in suspension by turbulence in the flowing water for considerable periods of time without contact with the stream bed

Dissolved Load

the portion of a stream's total sediment load that is carried in solution, especially ions from chemical weathering

Critical Settling Velocity (CSV)

when the settling velocity equals the surface loading, the sediment will flow with the river

V-shaped Valley

A valley that is formed by erosion from a river or stream over time

Meander

when water flows in a curvy, bendy path, like a snake

Oxbow Lake

a meander of a stream, river or creek, that has become separated from the flow of water

Cut-off

loop that shortens and straightens the course of the stream

Neck

the upland between opposing meanders of a stream

Cut bank

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The outside curve of a river meander, where erosion is greatest due to

Point Bar

A low, curved ridge of sand and gravel along the inner bank of a meandering stream

Natural levee

The natural movement of a body of water pushes sediment to the side

Delta

the flat, low-lying plain that sometimes forms at the mouth of a river from deposits of sediments

Alluvial Fan

a triangle-shaped deposit of gravel, sand, and even smaller pieces of sediment, such as silt

Flood Plain

a generally flat area of land next to a river or stream

Yazoo Tributary

any tributary stream that runs parallel to, and within the floodplain of a larger river for considerable distance, before eventually joining it

Distributary

a river branch flowing away from the main stream

Aquifer

a body of permeable rock which can contain or transmit groundwater.

Continental Divide

the line of summits of the Rocky Mountains, separating streams flowing toward the Gulf of California and the Pacific Ocean from those flowing toward the Gulf of Mexico, Hudson Bay, and the Arctic Ocean.

headward erosion

a fluvial process of erosion that lengthens a stream, a valley or a gully at its head and also enlarges its drainage basin

Infiltration

permeation of a liquid into something by filtration

Potholes

a cylindrical, bowl-shaped, or irregular hollow that is usually deeper than wide

Zone of saturation

the portion of underground soil below the water table where all gaps are completely filled with water

Zone of Aeration

The area of an unconfined aquifer above the water table where the pore spaces among soil particles and rock formations are filled with air

Spring

A recharge area where water enters the subsurface

Porosity

the ratio of pore volume to total volume

Competence

 the largest particles that a river can transport

Downcutting

erode downward through its bed.

Capacity

The maximum volume of load that a river can carry at a specific point in its course