geography final

Geography
define aquifer
an underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, or silt) from which groundwater can be usefully extracted using a water well.
define zone of aeration
A region below the Earth’s surface that is marked by the presence of both water and air in the pores of rocks and soil. Also called aeration zone.

Read more: http://wiki.answers.com/Q/What_is_the_zone_of_aeration#ixzz1yjLt5sta

define zone of saturation
Underground region within which all openings filled with water. Top of zone of saturation is called water table. Water contained within zone of saturation is called groundwater.
what is the difference between a confined and unconfined aquifer?
Confined aquifers are permeable rock units that are usually deeper under the ground than unconfined aquifers. They are overlain by relatively impermeable rock or clay that limits groundwater movement into, or out of, the confined aquifer.

Where groundwater is in direct contact with the atmosphere through the open pore spaces of the overlying soil or rock, then the aquifer is said to be unconfined. The upper groundwater surface in an unconfined aquifer is called the water table. The depth to the water table varies according to factors such as the topography, geology, season and tidal effects, and the quantities of water being pumped from the aquifer.

what is the water table? & What causes it to fluctuate?
The top of the saturated zone.
1) change in the volume of water stored in the
aquifer, 2) changes in atmospheric pressure, and 3) changes caused by aquifer deformation. Many of the causes of water-level changes can be easily recognized simply by the shape of the
define porosity
is a measure of how much of a rock is open space. This space can be between grains or within cracks or cavities of the rock.
define permeability
is a measure of the ease with which a fluid (water in this case) can move through a porous rock.
where are the recharge areas located
above an aquifer.
where are the discharge areas located
Ground water discharge occurs where the water table or potentiometric surface intersects the land surface.
what effects the rate of groundwater movement
hydraulic conductivity, (commonly called permeability) porosity, and the hydraulic gradient. The hydraulic conductivity is a measure of the water transmitting capability of an aquifer
what causes a cone of depression and saltwater intrusion?
A cone of depression occurs in an aquifer when groundwater is pumped from a well.
define artesian well
Salt water intrusion occurs in coastal freshwater aquifers when the different densities of both the saltwater and freshwater allow the ocean water to intrude into the freshwater aquifer.
what are some causes of groundwater contamination?
Groundwater can become contaminated in many ways. If rain water or surface water comes into contact with contaminated soil while seeping into the ground, it can become polluted and can carry the pollution from the soil to the groundwater. Groundwater can also become contaminated when liquid hazardous substances themselves soak down through the soil or rock into the groundwater. Some liquid hazardous substances do not mix with the groundwater but remain pooled within the soil or bedrock. These pooled substances can act as long-term sources of groundwater contamination as the groundwater flows through the soil or rock and comes into contact with them.
what is happening to the groundwater in the High Plains -the ogallala or high plains aquifer?
amount is declining
what is the importance of our groundwater resources?
we use it all the time.
What is the connection between groundwater and surface water
The water in lakes, rivers, or oceans is called surface water…it’s on the surface. Groundwater and surface water sometimes trade places. Groundwater can move through the ground and into a lake or stream. Water in a lake can soak down into the ground and become groundwater.
what 3 processes are associated with streams?
what is a drainage basin (watershed)?
an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin
what are divides?
what variables influence a stream’s drainage pattern?
type of bedrock
what is a streams discharge?
he volume rate of water flow, including any suspended solids (i.e. sediment), dissolved chemical species (i.e. CaCO3(aq)) and/or biologic material (i.e. diatoms), which is transported through a given cross-sectional area
what causes a streams discharge to increase?
velocity
define capacity?capacity
how much sediment a stream can carry
define competence
determined by diameter of largest particles that can be carried by stream
define exotic stream… why is colorado river an example of this?
A stream that crosses a desert as it flows to the sea.
what variables effect the rate of stream erosion
define abrasion
the mechanical scraping of a rock surface by friction between rocks and moving particles during their transport by wind, glacier, waves, gravity, running water or erosion. After friction, the moving particles dislodge loose and weak debris from the side of the rock.
define attrition
a form of coastal or river erosion, when the bed load is eroded by itself and the bed
where will erosion occur in a meandering stream?
outside of stream, called cutbank
what is the difference between lateral and vertical erosion? & where do they occur?
vertical erosion is when the ground is eroded downward and creates a valley in the earth. Lateral erosion, on the other hand, is when a river erodes the walls of its passageway and makes itself wider.
what are 3 ways that a stream carries it’s load, and what is in these?
how does a bedload move?
define sinuous stream channel
very common, winding with gentle irregular curves
define straight stream channel
uncommon, controlled by strong geologic structure
define meandering stream channel
smooth, regular curves.
define braided stream channel
stream load exceed capacity excess sediment is deposited and new channels form (main load is “bedload”
how do oxbow lakes form?
when a portion of stream erodes through and forms a cut off…stream no longer follows old channel…eventually fills with veg and creates a meander scar
4 areas of stream deposition, what forms?
inside of curves in meandering, floodplain, deltas, alluvial fans-(sediment forms a fan like shape when it reaches plateau)
what is the cycle of erosion?
young mature and old
define rejuvenation… what causes this?
tectonic forces can cause uplift of land and this occurs
how does urbanization impact river systems?
chemical composition of oceans? why does salinity vary?
several dissolved minerals, dominated by sodium and chlorine-forms sodium chloride. it varies 3.5-3.7% depending on rate of evaporation and quantity of fresh water inflow from rivers and precipitation
define littoral zone
includes land and ocean (the part of a sea, lake or river that is close to the shore.)
difference between shoreline and coast
where ocean meets land … and strip of land with unique landscapes, dunes, sea cliffs, coastal plain…
what causes tides?
what causes waves
strong winds, oscillatory or circular movement
define wavelength
crest to crest
define height (waves)
crest to trough
define crest (waves)
upward movement creates this
define trough (waves)
downward movement creates this
define wave period
time between two successive wave crests
what determines the height of waves? general motion of waves?
Wind speed, duration, and fetch (the distance it blows over open water)
what happens as the waves approach the shore & Why?
slow down because of friction
define wave refraction
the change in direction of a wave due to a change in its speed.
define longshore current
the current that develops parralel to a coast when waves approach the coast obliquely and forward momentum is deflected.
define swash and backwash
is known as a turbulent layer of water that washes up on the beach after an incoming wave has broken.

The flow back to the sea after the wave have broken

define beach drift
the drifting of sediments, especially marine sediments, in patterns parallel to the contours of a beach, due to the action of waves and currents.
what happens to an angular shoreline
waves reach some areas before others, as a result, part of wave is retracted and erosion occurs… sediment is deposited and overtime shoreline is straightened.
how do beaches form & what causes variation in composition
sediment composed of large rocks, gravel, coral, sand, shells.

the different composition is caused by spit, baymouth bar, tombolo, barrier islands. (a deposition landform in which an island is attached to the mainland by a narrow piece of land such as a spit or bar.)

why do beaches change seasonally?
he beach profile changes seasonally due to the change in wave energy experienced during summer and winter months. The beach profile is higher during the summer due to the gentle wave action during this season. The lower energy waves deposit sediment on the beach berm and dune, adding to the beach profile. Conversely, the beach profile is lower in the winter due to the increased wave energy associated with storms. Higher energy waves erode sediment from the beach berm and dune, and deposit it off shore, forming longshore bars.
depositional and erosional landforms… what is the difference?
depositional…

erosional… need exposed rock, steep slope and deep water, water hits with high energy and erodes rock…sea cliff, sea cave, sea arches, wave cut platform,

how do barrier islands form? what are they?
a coastal landform and a type of barrier system, are relatively narrow strips of sand that are parallel to the mainland coast
what causes estuaries to develope
Most modern-day estuaries were formed during the Holocene epoch by the flooding of river-eroded or glacially scoured valleys when sea level began to rise about 10,000-12,000 years ago.
why are estuaries important?
The sheltered waters of estuaries are home to countless plants and animals that like to live in water that is part fresh and part salty.
why are wetlands, coastal marshes & swamps good habitats
Wetlands are habitats that fall somewhere on the environmental spectrum between land and water. Since wetlands lie at the interface of terrestrial and aquatic habitats, they possess a unique mixture of species, conditions, and interactions. As a result, wetlands are among our planet’s most diverse and varied habitats.
what are coral reefs & and what’s happening to them
resistant marine ridges or mounds consisting largely of compacted coral together with algal material and biochemically deposited calcium carbonates. (living shoreline) unique unique ecosystem, sunlight warm water (over 68F) normal salinity, clean water

global warming, coral bleaching, pollution , dredging

human impacts on coastlines?
50% live within 120 mi of coast, loss of wetlands, salt marshes, swamps have increased erosion, avg. erosion on atlantic coast 2-3 inches/year (higher along gulf)
what structures/devices are used to prevent sand movement along coastlines?
sea walls, groins and jettys, breakwater, dune grass & natural vegetation, beach nourishment
how does global warming have a projected impact on coastal regions?
melting ice caps and warming temps will create a higher sea level. this could create coastal flooding.
evolution of streams and valleys
youth stage-river erodes land into v-shape valley due to vertical erosion,steep gradient, highly erosive, turbulent water, no flood plain

mature stage- gradient is less, lateral erosion occurs widening the channel, erosion=deposition, meanders, beginning of floodplain

Old Age- wide river valleys, wide meanders, oxbow lakes, low elevation, gentle slope, very large floodplain basedlevel is reached, stream no longer erodes, deltas

estuary
where fresh water meets salt water

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