Exam 2 (Ch. 6-10) Flashcards
When water infiltrates into the ground, moves to water table, and flows with groundwater to stream
Groundwater flow
Area drained by a single stream or river
Drainage basin
Smaller streams that contribute to larger streams
Tributaries
Large stream that tributaries flow into
Trunk stream
Slope of the land over which the river flows, and levels off as the river approaches its base
Gradient
Steeper-sided and deep valley profile near headwaters, with a wide floodplain usually present near base level
Cross-sectional profile
When rivers transport materials along water
Load
Total load: materials that roll, slide, and bounce.
Bed load
Total load: silt and clay particles carried.
Suspended load
Total load: materials carried as chemical solution.
Dissolved load
Volume of water passing a given point over a period of time
Discharge
A stream’s discharge ________ downstream.
Increases
Key process in the Earth system changes in area lead to changes in velocity
Erosion
Water will carry more sediment when it has a higher:
Velocity
Water will have a greater erosive power if there is a ________ velocity and ________ sediment.
Higher; more
Greater erosion results in a ________, ________ channel.
Deeper; wider
When discharge increases, what can a river do to accommodate extra water?
Raise velocity (go faster), erode downward (increase channel depth), or erode laterally (increase width)
If an increase in discharge happens too quickly, it produces a:
Flood
Meandering pattern: curving channel bends.
Meanders
Meandering pattern: velocity increases on the outside of curves causing erosion.
Cutbank
Meandering pattern: rivers slow on inside of curves, causing deposition.
Point bar
Meandering pattern: when streams shift position.
Avulsion
Zones: generally in upper parts, where there is steeper topography and more precipitation.
Zone 1: Zone of Production
Zones: broad valley and floodplain, sediment frequently deposited in river balls or on the floodplain, braided or meandering or combination of both.
Zone 2: Zone of Transport
Zones: alluvial fan, lake, delta (most common).
Zone 3: Zone of Deposition
Why do people live on floodplains?
Great for soil, good transportation, flat, and easy to build on
Do levees and floodwalls protect from flooding?
No, gives false sense of security.
What are two ways that levees fail?
- Overtopping (floodwater raises so high it flows over the top)
- Breaching (water breaks through weak point)
Thin out levee when rising flood hits it
Wave attack
When the force of flooding causes the levee to break and slump
Slumping
Water finds a weak spot, seeps through, causes failing and slumping
Piping
When water is pushed through a naturally permeable layer, popping out on the other side
Underseepage
Stream discharge when water overflows the channel banks
Flood discharge
Height of water in the river
Stage
Graph of stream discharge or water depth over time
Hydrograph
When water flows over surface downhill and into streams
Surface runoff
The time that elapses between when a rainfall event occurs and when the flooding occurs on the stream
Lag time
Surface water can be increased by:
Frozen ground, saturated ground, urbanization, or deforestation/intensive agriculture
Average time between flood events of a certain size
Recurrence interval
Statistical estimation of the likelihood that a certain discharge will be equaled or exceeded in any given year
Probability
Could there be a flood next year in Bowling Green?
Yes, but with probability of 1/100 every year.
What are the primary effects of floods? Secondary?
Injury, loss of life, damage, erosion, or redeposition
Short-term contamination, pollution of rivers, displacement
Straightening, deepening, widening, clearing, or lining existing stream channels
Channelization
What are the 3 types of landslides/mass wasting?
- Falling (free falling of earth material)
- Sliding (movement of material as a coherent block)
- Flow (movement of unconsolidated matter)
The steepest slope that unconsolidated material can hold without collapse, often 30o
Angle of repose
Behave like fluids , all sizes of material, wet to dry, barely moving to >200mph
Flow
Very fine-grained sediment, can absorb lots of water, tend to align parallel sheets
Clay
Slowest, most widespread from of slope failure, swelling and shrinking of soil
Creep
Concrete or wire-filled baskets (walls)
Retaining walls
What are the two types of weathering?
Physical and chemical
Describe physical weathering.
Breaking into smaller pieces
Describe chemical weathering.
Change chemistry of rocks
Solid earth material that has been altered such that it can support rooted plant life; product of weathering
Soil
Created from vertical and horizontal movements, distinct layers
Soil profile
Soil profile: organic material layer.
O layer
Soil profile: mineral and organic materials, leaching occurs.
A layer
Soil profile: minerals, leaching occurs, “zone of leaching.”
E layer
Soil profile: enriched in clay, iron oxides, “zone of accumulation.”
B layer
Soil profile: partially altered (weathered) parent material.
C layer
Soil profile: unweathered parent material.
R layer
Define the colors of each layer of soil profiling.
O and A: dark (organic material)
E: white (leaching)
B: yellow-brown to red-brown
Ground failure characterized by sinking or vertical deformation of land.
Subsidence
Rocks are dissolved and groundwater level drops, leaving behind ________, or ________.
Caverns; sinkholes
Sinkholes: acidic groundwater becomes concentrated in holes in joints and fractures in the rock.
Solutional sinkholes
Sinkholes: develop by the collapse of material into an underground cavern.
Collapse sinkholes
Karst topography: large, steep, limestone “towers,” created in highly eroded karst regions.
Tower Karst
Karst topography: streams flow directly into the groundwater solution.
Disappearing streams
Karst topography: where groundwater naturally discharges at the surface.
Springs
Sediment compacts when water is removed, common on river deltas, natural flooding replenishes sediment, thwarting collapse
Fine sediment
Dust deposits, loess, and stream deposits in arid regions are bound with clay or water soluble materials
Collapsible soils
Wetland soils contain large amounts of organic matter and water, when water is drained or soil is decomposed, soils collapse
Organic soils
Extracting groundwater in greater volumes than it is replenished through rain and surface water
Groundwater mining
If California needs rain so badly, then why are farmers still worried about flooding?
Levees subsiding (lowering), so more water can get it.
Why is the radon risk ignored?
Radon is invisible, colorless, odorless, naturally occurring, lung cancer does not occur in children, hard to link to death, long latency, lack of press, no sensory reminders.
What is radon?
Gas, naturally occurring, enters buildings from soil beneath, invisible and odorless.
How does radon enter the home?
- Cracks in solid floors
- Construction joints
- Cracks in walls
- Gaps in suspended floors
- Gaps around service pipes
- Cavities inside walls
- The water supply
At what level of pCi/L should you get your home fixed?
4 or more pCi/L
Where is asbestos found?
Product of metamorphism with unaxial tension strain.
Lungs become hard, scarred, inflamed (trouble breathing)
Asbestosis
Rare cancer affecting lining of lungs
Mesothelioma
Difficult to tie asbestiform minerals
Lung cancer
What is the “One Fiber” theory?
One fiber is sufficient to cause an asbestos-related disease.
Found between Mars and Jupiter, rock (stony), metal (iron), or combinations
Asteroids
Broken up asteroids
Meteoroids
Meteoroids that burn up in Earth’s atmosphere, create “shooting star”
Meteors
Have glowing tails
Comets
What’s the difference between simple and complex craters?
Simple craters: small 4miles in diameter, rim collapses more completely, center uplifts following impact
Based on belief in a “young Earth” incorrectly though that all processes on Earth were rapid, catastrophic in nature
Catastrophism
Present geological processes, Earth older than 6,000 years. Present = “key to past.” Understanding of plate tectonics formed. “Punctuated equilibrium.”
Uniformitarianism
Sudden loss of large numbers of plants and animals relative to number of new species added, defines boundary of geological periods or epochs, usually involve rapid climate change
Mass Extinctions
Where did the mass extinctions of the dinosaurs occur?
At the K-T boundary (K - Cretaceous, Pg - Paleogene)
How do we monitor space for nearby threatening objects?
NEAT project (Near-Earth Tracking)
