Pg Test 3 Chapter 9

Front 1

Hydrologic Cycle

Back 1

The undending cycle of water constantly moving from the oceans, to the atmosphere, to the solid earth, and to the biosphere

Front 2

Infiltration

Back 2

occurs when the precipitation of water returns to the land. It is the portion that soaks into the ground

Front 3

runoff

Back 3

When the amount of precipitation exceeds the capacity for infiltration, the surplus water flows over the land surface into water bodies thorugh a process called runoff.

Front 4

Transpiration

Back 4

the situation in which some of the water that infiltrates the ground is absorbed by plants which release the water into the atmosphere

Front 5

Sheet flow

Back 5

runoff begins to flow in broad, unconfined, thin sheets.

Front 6

What determines runoff amount

Back 6

infiltration capacity of the soil

Front 7

Determinants of infiltration capacity

Back 7

1.Intensity and duration of rainfall
2.Prior wetted condition of the soil
3.Soil texture
4.Slope of the land
5.Nature of vegatative cover

Front 8

Rills

Back 8

The tiny channels deveeloped by currents of sheet flow which carry water to a stream

Front 9

Stream

Back 9

"a general term to denote the flow of water within any natural channel. Thus, a small creek and a large river are both streams".

Front 10

Gradient

Back 10

The slope of a stream chanel expressed as the vertical drop of a stream over a specified distance is gradient

Front 11

Discharge

Back 11

The discharge of a stream is the volume of water flowing in the stream. Usually measured in cubic meters per second.

Front 12

Discharge is equal to

Back 12

The stream's cross-sectional area X its velocity

Front 13

Head or Headwaters

Back 13

"the vertical distance between the recharge and the discharge points of a water table. Also the source area of beginning or of a valley".

Front 14

Mouth

Back 14

"the point downstream where a river empties into another body of water"

Front 15

Ultimate base level

Back 15

Sea level

Front 16

Local or temporary base level

Back 16

can be resistant layers of rocks or main streams

Front 17

Base Level

Back 17

The lower limit to how deep a stream can erode. Lowering base level will cause a stream to gain energy and erode. Any change in abse level will cause a corresponding readjustment of stream activities

Front 18

Meanders

Back 18

The bends and turns that streams in a broad flat floored valled that is nea ra base level typically follow. If base level changes, the stream channel will change to balance again, resultingin incised meanders

Front 19

Erosion

Back 19

"the incorporation and transportation of material by a mobile agent, such as water, wind or ice".

Front 20

Capacity

Back 20

The maximum load it can carry. Directly related to its discharge, the greater the volume of water flowing in a stream, the greater its capacity for hauling sediment.

Front 21

Competence

Back 21

Measures the maximum size of particles the stream is capable of transporting. Velocity gets cubed.

Front 22

Sorting

Back 22

Stream transport provides a mechanism by which solid particles of various sizes are seperated, this process is called ____, and explains why particles of a same size are deposited together. It is important because each particle size has a critical settling velocity.

Front 23

Alluvium

Back 23

The material deposited by a stream is called alluvium, the general term for any stream deposited sediment. Several features can be produced as the stream deposits certain sediments

Front 24

Bars

Back 24

Channel deposits composed of sand and gravel

Front 25

Point bars

Back 25

deposits in the inside of a meander. Debris that is acquired by a stream at the cut bacnk movesdownstream withthe coarser material generally being deposited as point bars in zones of decreased velocity on the inseides of the meanders. In this situation, the meanders migrate laterally by eroding the outside of the bends and depositing on the inside.

Front 26

Deltas

Back 26

exists in oceans or basins

Front 27

Natural Levees

Back 27

Form parallel to the stream channel. Area behind natural levees may contain back swamps or yazoo tributaries

Front 28

well sorted

Back 28

a deposit of sediment consisting of one sediment size

Front 29

poorly sorted

Back 29

a deposit of sediment consisting in more than one size

Front 30

Braided

Back 30

streams are termed this way when they consist so f a complex network of converging and diverging channels that thread their way among numerous islands or gravel bars and have an intwoven appearance.

Front 31

How does a "Braided" characteristic become produced

Back 31

These form when a large proportion of the stream's load consists of coarse material (sand and gravel) and the stream has a highly variable discharge. This bank material is readily erodible, so these types of channels are wide and shallow.

Front 32

Floodplain

Back 32

A flat, broader valley floor covered with alluvium is termed this way. It is appropriately done so because when a river overflows its bank during a flood stage, it iunudates the floodplain

Front 33

Natural Levees- Production

Back 33

These are built by successive floods over many years. The elevated landforms composed of alluvium that parallel some streams and act to confine their water, except during a flood stage.

Front 34

Backswamps

Back 34

a pooorly drained area on a flood plain, resulting when natural levees are present.

Front 35

Yazoo Tributaries

Back 35

A trubutary that flows parallel to the main stream beacause a natural levee is present

Front 36

Delta (Detailed)

Back 36

When a stream enters the relatively still waters of an ocean or a lake its velocity drops abruptly and the resulting depositts form a delta. "An accumulation of sediment formed where a stream enters a lake or ocean" **A deposit that forms where a river meets a lake or an ocean

Front 37

Distributaries

Back 37

A section of a stream that leaves the main flow

Front 38

Cut Bank

Back 38

The outside zone of the meander which is very active

Front 39

Drainage Basin

Back 39

The land area that contributes water to a river system

Front 40

Divide

Back 40

The drainage basin of one stream is seperated by another by this imaginary line. These line sizes vary, in scale from a ridge seperating two small gullies on a hillside to a continental diveide that splits whole continents into enormous drainage basins

Front 41

Flood

Back 41

"the overflow of a stream channel that occurs when discharge exceeds the chanel's capactiy. This is the most common geologic and destructive hazard".