Chapter 16
Abrasion:
The grinding and scaping of a rock surface by the friction and impact of rock particles carried by water, wind, and ice.
Alluvium:
	Unconsolidated sediment deposited by a stream.
Base level:
	The level below which a stream cannot erode.
Cut bank:
	The area of active erosion on the outside of a meander.
Delta:
	An accumulation of sediment formed where a stream enters a lake or an ocean.
Discharge:
	The quantity of water in a stream that passes a given point in a period of time.
Drainage basin:
	The land area that contributes water to a stream.
Flood:
The overflow of a stream channel that occurs when discharge exceeds the channel’s capacity. The most common and destructive geologic hazard.
Gradient:
	The slope of a stream, generally expressed as the vertical drop over a fixed distance.
Head (headwaters):
	The beginning or source area for a stream. Also called the headwaters.
Infiltration:
	The movement of surface water into rock or soil through cracks and pore spaces.
Laminar flow:
The movement of water particles in straight-line paths that are parallel to the channel. The water particles move downstream without mixing.
Longitudinal profile:
	A cross section of a stream channel along its descending course from the head to the mouth.
Meanders:
	A looplike bend in the course of a stream.
Natural levee:
An elevated landform composed of alluvium that parallels some streams and acts to confine their waters, except during bloodstage.
Point bar:
	A crescent-shaped accumulation of sand and gravel deposited on the inside of a meander.
Runoff:
	Water that flows over the land rather than infiltrating into the ground.
Saltation:
	Transportation of sediment through a series of leaps or bounces.
Turbulent flow:
The movement of water in an erratic fashion often characterized by swirling, whirlpool-like eddies. Most streamflow is of this type.
#9) In what three ways does a stream transport its load?
Solution: Items that dissolve in water are carried in the water
Floatation: objects less dense than water are carried on the surface.
Suspension: particles small enough to be picked up by water turbulence and carried some distance before they settle back out.

#11) Explain the difference between capacity and competency.
	Capacity: how much sediment is transported.
	Comptetence: how big the particles are in a stream.
Chapter 17
Aquifer:
	Rock or sediment through which groundwater moves easily.
Aquitard:
	An impermeable bed that hinders or prevents groundwater movement.
Capillary fringe:
A relatively narrow zone at the base of the zone of aeration. Here water rises from the water table in tiny, threadlike openings between grains of soil or sediment.
Cone of depression:
	A cone-shaped depression in the water table immediately surrounding a well.
Drawdown:
The difference in height between the bottom of a cone of depression and the original height of the water table.
Groundwater:
	Water in the zone of saturation.
Hydraulic gradient:
The slope of the water table. It is determined by finding the height difference between two points on the water table and dividing by the horizontal distance between the two points.
Karst topography:
A type of topography formed on soluble rock (especially limestone) primarily by dissolution. It is characterized by sinkholes, caves, and underground drainage.
Water table:
	The upper level of the saturated zone of groundwater.
Well:
	An opening bored into the zone of saturation.
#3) Compare and contrast the unsaturated zone and the zone of saturation. Which zone contains groundwater?
The voids in the saturated zone are completely filled with water. The voids in the unsaturated zone contain both air and water. The saturated zone contains groundwater.
#7) Distinguish between porosity and permeability.
Permeability refers to how well water flows through a material that’s controlled by how well connected they are and how large the pores are.
	Porosity is the amount of void space in a rock or other earth material.

 Chapter 18
Define the following words:
Abrasion:
The grinding and scaping of a rock surface by the friction and impact of rock particles carried by water, wind, and ice.
Glacial drift:
An all-embracing term for sediments of glacial origin, no matter how, where, or in what shape they were deposited.
Glacier:
A thick mass of ice originating on land from the compaction and recrystallization of snow that shows evidence of past or present flow.
Ice sheets:
A very large, thick mass of glacial ice flowing outward in all directions from one or more accumulation centers.
Plucking:
	The process by which pieces of bedrock are lifted out of place by a glacier.
Stratified drift:
	Sediments deposited by glacial meltwater.
Till:
	Unsorted sediment deposited directly by a glacier.
Valley (alpine) glacier:
	A glacier confined to a mountain valley, which in most instances had previously been a stream valley.
Chapter 19
Alluvial fan:
	A fan-shaped deposit of sediment formed when a stream’s slope is abruptly reduced.
Deflation:
	The lifting and removal of loose material by wind.
Desert:
	One of the two types of dry climate; the driest of the dry climates.
Dune:
	A hill or ridge of wind-deposited sand.
Ephemeral stream:
A stream that is usually dry because it carries water only in response to specific episodes of rainfall. Most desert streams are of this type.
Loess:
Deposits of windblown silt, lacking visible layers, generally buff-colored, and capable of maintaining a nearly vertical cliff.
Steppe:
One of the two types of dry climate. A marginal and more humid variant of the desert that seperates it from bordering humid climates.
#8) What is the most important erosional agent in deserts?
Water because the movement of flash-floodwater erodes all in its path.
Chapter 20
Beach:
	An accumulation of sediment found along the landward margin of the ocean or a lake.
Beach drift:
The transport of sediment in a zigzag pattern along a beach, caused by the uprush of water from obliquely breaking waves.
Beach nourishment:
Process in which large quantities of sand are added to the beach system to offset losses caused by wave erosion. Building beaches seaward improves beach quality and storm protection.
Longshore current:
	A nearshore current that flows parallel to the shore.
Wave refraction:
A change in direction of waves as they enter shallow water. The portion of the wave in shallow water is slowed, which causes the waves to bend and align with the underwater contours.
Metamorphic rock:
Rock formed by the alteration of preexisting rock deep within Earth by heat, pressure, and/or chemically active fluids.
Rock cycle:
A model that illustrates the origin of the three basic rock types and the interrelatedness of Earth materials and processes.
Plate tectonics:
The theory that proposes that Earth’s outer shell consists of individual plates that interact in various ways and thereby produce earthquakes, volcanoes, mountains, and the crust itself.
12) List the three types of plate boundaries and describe the relative motion at each of them.
Divergent plate boundaries:
Two plates move apart, resulting in upwelling of hot material from the mantle to create new seafloor.
Convergent plate boundaries:
Two plates move together, resulting in oceanic lithosphere descending beneath an overriding plate, eventually to be reabsorbed into the mantle, or possibly in the collision of two continental blocks to create a mountain system.
Transform fault boundaries:
Two plates grind past each other without the production or destruction of the lithosphere.