Geography 132 Exam 2

Front 1

hydrology (pg. 432)

Back 1

The science of water,its global circulation, distribution, and properties, specifically water at and below Earth's surface.

Front 2

fluvial (pg. 432)

Back 2

Stream-related processes; from the Latin "fluvius" for river or running water.

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erosion (pg. 433)

Back 3

Denudation by wind, water, or ice which dislodges, dissolves, or removes surface material.

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transport (pg. 433)

Back 4

The actual movement of weathered and eroded materials by air, water, and ice.

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deposition (pg. 433)

Back 5

The process whereby weathered, wasted, and transported sediments are laid down by air, water, and ice.

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alluvium (pg. 433)

Back 6

General descriptive erm for clay, silt, sand, gravel, or other unconsolidated rock, and mineral fragments transported by running water and deposited as sorted or semi-sorted sediment on a floodplain, delta, or stream bed.

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base level (pg. 433)

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A hypothetical level below below which a stream cannot erode its valley, and thus the lowest operative level for denudation processes; in an absolute sense, it is represented by sea level, extending under the landscape.

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drainage basin (pg. 433)

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The basic spatial geomorphic unit of a river system; distinguished from a neighboring basin by ridges and highlands that form divides, marking the limits of the catchment area of the drainage basin or its watershed.

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watershed (pg. 434)

Back 9

The catchment area of a drainage basin; delimited by divides (see drainage basin).

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sheet flow (pg. 434)

Back 10

Surface water that moves downslope in a thin film as overland flow, not concentrated in channels larger than rills.

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continental divides (pg. 434)

Back 11

A ridge or elevated area that separates drainage on a continental scale; specifically, that ridge in North America that separates drainage to the Pacific on the west side from drainage to the Atlantic and Gulf on the east side and to Hudson Bay and the Arctic Ocean in the north.

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internal drainage (pg. 436)

Back 12

In regions where rivers do not flow into the ocean, the outflow is through evaporation or subsurface gravitational flow.

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drainage density (pg. 437)

Back 13

A measure of the overall operational efficiency of a drainage basin, determined by the ratio of combined channel lengths to the unit area.

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drainage pattern (pg. 437)

Back 14

A distinctive geometric arrangement of streams in a region, determined by slope, differing rock resistance to weathering and erosion, climatic and hydrologic variability, and structural controls of the landscape.

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discharge (pg. 439)

Back 15

The measured volume of flow in a river that passes by a given cross section of a stream in a given unit of time; expressed in cubic meters per second or cubic feet per second.

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exotic stream (pg. 441)

Back 16

A river that rises in a humid region and flows through an arid region, with discharge decreasing toward the mouth; for example, the Nile and Colorado Rivers.

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hydraulic action (pg. 442)

Back 17

the erosive work accomplished by the turbulence of water; causes a squeezing and releasing action in joints in bedrock; capable of prying and lifting rocks.

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abrasion (pg. 442)

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Mechanical wearing and erosion of bedrock accomplished by the rolling and grinding of particles and rocks carried in a stream, removed by wind in a "sandblasting" action, or imbedded in glacial ice.

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dissolved load (pg. 442)

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Materials carried in chemical solution in a stream, derived from minerals such as limestone, dolomite, or from soluble salts.

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suspended load (pg. 442)

Back 20

Fine particles held in suspension in a stream. The finest particles are not deposited until the stream velocity nears zero.

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bed load (pg. 443)

Back 21

Coarse materials that are dragged along the bed of a stream by traction or by the rolling and bouncing motion of saltation; involves particles too large to remain in suspension.

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traction (pg. 443)

Back 22

A type of sediment transport that drags coarser materials along the bed of a stream.

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saltation (pg. 443)

Back 23

The transport of sand grains (usually larger than 0.2mm, or 0.008 in.) by stream or wind, bouncing the grains along the ground in asymmetrical paths.

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aggradation (pg. 443)

Back 24

The general building of land surface because of deposition of material; opposite of degradation. When the sediment load of a stream exceeds the stream's capacity to carry it, the steam channel becomes filled through this process.

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braided stream (pg. 443)

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A stream that becomes a maze of interconnected channels laced with excess sediment. Braiding often occurs with a reduction of discharge that reduces a stream's transporting ability or with an increase in sediment load.

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meandering stream (pg. 443)

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The sinuous, curving pattern common to graded streams, with the energetic outer portion of each curve subjected to the greatest erosive action and the lower-energy inner portion receiving sediment deposits.

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undercut bank (pg. 443)

Back 27

In streams, a steep bank formed along the outer portion of a meandering stream; produced by lateral erosive action of a stream; sometimes called a cutbank.

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point bar (pg. 443)

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In a stream, the inner portion of a meander, were sediment fill is redeposited.

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oxbow lake (pg. 444)

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A lake that was formerly part of the channel of a meandering stream; isolated when a stream eroded its outer bank forming a cutoff through the neck of a looping meander.

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gradient (pg. 444)

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The drop in elevation from a stream's headwaters to its mouth, ideally forming a concave slope.

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graded stream (pg. 446)

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An idealized condition in which a stream's load and the landscape mutually adjust. This forms a dynamic equilibrium among erosion, transported load, deposition, and the stream's capacity.

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nickpoint (pg. 447)

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The point at which the longitudinal profile of a stream is abruptly broken by a change in gradient; for example, a waterfall, rapids, or cascade.

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floodplain (pg. 449)

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A flat, low-lying area along a stream channel, created by and subject to recurrent flooding; alluvial deposits generally mask underlying rock.

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natural levees (pg. 449)

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A long, low ridge that forms on both sides of a stream in a developed floodplain; they are depositional products (coarse gravels of sand) of river flooding.

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yazoo tributary (pg. 449)

Back 35

A small tributary stream draining alongside a floodplain; blocked from joining the main river by its natural levees and elevated stream channel.

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backswamp (pg. 452)

Back 36

A low-lying, swampy area of a floodplain; adjacent to a river, with the river's natural levee on one side and higher topography on the other.

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alluvial terraces (pg. 452)

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Level areas that appear as topographic steps above a stream, created by the stream as it scours with renewed downcutting into its floodplain; composed of unconsolidated alluvium.

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delta (pg. 452)

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A depositional plain formed where a river enters a lake or an ocean; named after the triangular shape of the Greek letter delta.

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estuary (pg. 454)

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The point at which the mouth of a river enters the sea, where freshwater and seawater are mixed; a placed where tides ebb and flow.

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flood (pg. 460)

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A high water level that overflows the natural riverbank along any portion of a stream.

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hydrograph (pg. 464)

Back 41

A graph of stream discharge (in cms or cfs) over a period of time (minutes, hours, days, years) at a specific place on a stream. The relationship between stream discharge and precipitation input is illustrated on the graph.

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eolian (pg. 472)

Back 42

Caused by wind; refers to the erosion, transportation, and deposition of materials.

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deflation (pg. 472)

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A process of wind erosion that removes and lifts individual particles, literally blowing away unconsolidated, dry, or noncohesive sediments.

Front 44

desert pavement (pg. 472)

Back 44

On arid landscapes, a surface formed when wind deflation and sheetflow remove smaller particles, leaving residual pebbles and gravels to concentrate at the surface; resembles a cobblestone street.

Front 45

blowout depressions (pg. 473)

Back 45

Eolian erosion in which deflation forms a basin in areas of loose sediment. diameter may range up to hundreds of meters.

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ventifacts (pg. 474)

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A piece of rock etched and smoothed by eolian erosion - abrasion by windblown particles.

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yardangs (pg. 474)

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A streamlined rock structure formed by deflation and abrasion; appears elongated and aligned with the most effective wind direction.

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surface creep (pg. 475)

Back 48

A form of eolian transport that involves particles too large for saltation; a process whereby individual grains are impacted by moving grains and slide and roll.

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dune (pg. 476)

Back 49

A depositional feature of sand grains deposited in transient mounds, ridges, and hills; extensive areas called sand seas.

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erg desert (pg. 476)

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A sandy desert,or area where sand is so extensive that it constitutes a sand sea.