Geology Quiz
Chapter 15 Streams and Floods
Chapter 16 Groundwater
1) The world's oceans contain approximately what percentage of the Earth's water?
A) 75%.
B) 83%.
C) 86%.
D) 97%.
2) Geologists use the term "stream" to refer to:
A) small local creeks.
B) tributaries to rivers.
C) major rivers.
D) all the above.
3) Every stream carries water from a watershed that is separated from other watersheds by a:
A) drainage basin.
B) drainage divide.
C) floodplain.
D) tributary.
4) In a curved section of a stream channel, the fastest water is:
A) near the inside of the curve.
B) near the outside of the curve.
C) in the middle of the stream.
D) relatively equal throughout the stream.
5) A 150-kilometer-long stream has a gradient of 10 feet per kilometer. The streams velocity at a point X, exactly
halfway between the source and the mouth, is 5 meters per second. The depth of the stream is 2 meters, and the
width is 8 meters. What is the correct estimate of the stream's discharge at point X?
A) 600 cubic meters per second.
B) 400 cubic meters per second.
C) 80 cubic meters per second.
D) 40 cubic meters per second.
6) A stream's base level is:
A) the average elevation of the stream channel.
B) the lowest level to which a stream can erode its channel.
C) the elevation of the head of a stream.
D) the gradient of the stream where it enters the ocean.
7) Which of the following statements concerning graded streams is NOT true?
A) The equilibrium of a graded stream is temporary and lasts only until the next change in its environment.
B) After a sudden increase in sediment load, the gradient increases, as does stream velocity.
C) After a sudden decrease in sediment load, the gradient decreases, as does stream velocity.
D) A graded stream responds instantaneously to any change in sediment load or discharge in such a way as to
establish a new graded state.
8) Stream valleys have a distinctive V-shape because:
A) as a stream erodes downward, it becomes graded and accomplishes less lateral erosion.
B) as a valley is cut, overland flow and mass movement remove loosened material from its slopes.
C) as a valley becomes established, there is less lateral meandering.
D) as a stream erodes downward, it encounters material more resistant to lateral erosion.
9) Which of the following statements about the processes of stream erosion is NOT true?
A) Potholes in bedrock are evidence of stream erosion by dissolution.
B) Abrasion and hydraulic lifting are more efficient in fast, turbulent streams than in slow ones.
C) Hydraulic lifting is erosion by water pressure.
D) Each year, dissolution is responsible for the removal of an estimated 3.5 million metric tons of rock from the
continents.
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10) Which of the following statements about stream drainage patterns is NOT true?
A) A radial drainage pattern occurs around topographic peaks, such as young volcanic cones.
B) A trellis drainage pattern occurs in areas containing narrow valleys separated by parallel ridges.
C) A rectangular drainage pattern occurs in areas that are nearly flat, such as the Midwestern and Great Plains states.
D) A dendritic drainage pattern occurs in areas with newly exposed coastal muds and massive plutonic igneous or
metamorphic rocks.
11) Stream piracy occurs when:
A) degradation causes the stream to erode its bed and reduce its gradient.
B) erosion causes a waterfall to migrate upstream and reduce its height until it no longer exists.
C) a stream cuts through a separating strip and bypasses a stream meander.
D) one stream captures the headwaters of another stream on the opposite side of a drainage divide.
12) The stream that erodes through its divide to capture the other slope drainage does so because of its:
A) steeper slope.
B) greater discharge.
C) less resistant streambed rocks.
D) all of the above.
13) Braided streams are caused by:
A) an exceptionally steep gradient.
C) an exceptionally high velocity.
B) an exceptionally high discharge.
D) an exceptionally high sediment load.
14) Streams meander because:
A) erosion occurs on the outside of curves while deposition occurs on the insides of curves.
B) streams typically carry a larger sediment load than their velocity can maintain.
C) streams are steered around materials that are more resistant to erosion.
D) streams are steered by slight elevation changes within their floodplain.
15) Waterfalls tend to:
A) migrate upstream and become smaller as erosion wears away their edge.
B) migrate downstream and become larger as sediment deposits accumulate on their edge.
C) remain stationary but increase in height as the falling water erodes deeper into their plunge pool.
D) remain stationary but decrease in height as erosion cuts downward in the upper channel.
16) Stream terraces indicate what overall geologic process?
A) Stream erosion in its channel.
B) Stream deposition in its channel.
C) A local rise in base level.
D) Local flooding in the stream valley.
17) A swift-flowing, relatively sediment-free stream transporting large boulders along its bed would be considered
to have a:
A) high capacity and high competence.
B) high capacity and low competence.
C) low capacity and high competence.
D) low capacity and low competence.
18) Which of the following statements concerning a stream's sediment load is NOT true?
A) Dissolved load is strongly affected by velocity.
B) Large stones that cannot be carried within a stream's suspended load can sometimes be transported by traction in
the stream's bed load.
C) Fine particles of clay are likely to be transported as part of the suspended load.
D) Both flat and low-density particles tend to remain within the suspended load.
19) Streams with large amounts of coarse, bed-load sediments deposit what bedform?
A) Floodplain.
B) Mid-channel bars.
C) Levees.
D) Backswamp.
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20) Accumulations of gold, platinum, or silver would most likely be found:
A) on the outside of meander curves, where the high velocity of the water has embedded them in the banks.
B) in potholes in the stream bed because their high density would cause them to sink lower than other sediments.
C) in point bars on the inside of meander curves, where stream velocity is the slowest.
D) distributed evenly throughout the stream bed.
21) Natural levees result when:
A) streams flood their banks and deposit sediment directly on top of the banks.
B) streams erode downward in their channel, leaving their banks higher relative to the surface of the stream.
C) hard, erosion-resistant rocks become part of a stream's banks.
D) yazoo streams flow parallel to a main stream and deposit material on the stream bank.
22) The primary difference between a delta and an alluvial fan is that:
A) alluvial fans are erosional features, whereas deltas are depositional features.
B) alluvial fans result from deposition into inland lakes, while deltas result from deposition into the ocean.
C) alluvial fans form at the source of a stream and deltas form at the mouth of a stream.
D) alluvial fans are formed on low-land plains, while deltas are formed in a standing body of water.
23) The Mississippi River near the college at the Coon Rapids dam:
A) is depositing bedload above the dam
B) best represents a braided river system
C) is rapidly down cutting above the dam by removing the stream bed load because of the increased depth of water
D) has been little impacted by the dam
24) Which of the following conditions is most favorable for delta formation?
A) Where waves and currents immediately sweep away most of the river's delivered sediments.
B) Where powerful storm waves carry all of the river's delivered sediment.
C) Where a large sediment load is delivered to quiet coastal waters.
D) Where a small sediment load is delivered along the river's short path to quiet coastal waters.
25) Flood prediction is based primarily on:
A) the statistical probability of a flood occurring within a given time.
B) computer models of meteorological cycles.
C) monitoring of flood precursors, such as increased groundwater levels and unusual plant behavior.
D) monitoring global levels of atmospheric moisture.
26) Artificial flooding on the Colorado River in 1996:
A) replenished beaches and sandbars along the river.
B) cleared debris from tributaries.
C) scoured sediment and vegetation along the banks.
D) all of the above.
27) All of the following materials encourage infiltration EXCEPT:
A) coarse sandstone.
B) fractured or jointed bedrock.
C) porous, unconsolidated clays.
D) loose soils and gravels.
28) The greatest infiltration of surface waters would be on:
A) steep slopes.
B) gentle slopes.
C) cliff faces.
D) steep, vegetated slopes.
29) The first water to move through a dry soil:
A) infiltrates downward into the zone of saturation. B) evaporates into the air trapped within soil pore spaces.
C) becomes attached to the surfaces of clay minerals or is used by plants. D) evaporates back into the atmosphere.
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30) Primary porosity would probably be the greatest in which of the following?
A) Fine, clayey mud.
B) Well-sorted, coarse-grained sediment.
C) Well-cemented, sedimentary rock.
D) Angular-grained, sedimentary rock.
31) Groundwater sometimes flows upward against gravity because:
A) groundwater is not governed by the same physical laws as surface water.
B) oversaturation occurs within the zone of saturation.
C) the pressure from overlying water and surrounding rocks forces groundwater to flow in specific directions.
D) groundwater is pulled by the flow of overlying surface water.
32) Groundwater would flow the fastest between two points if:
A) the hydraulic gradient and the hydraulic conductivity are both low.
B) the hydraulic gradient and the hydraulic conductivity are both high.
C) the hydraulic gradient is high and the hydraulic conductivity is low.
D) the hydraulic gradient is low and the hydraulic conductivity is high.
33) A perched water table is a water table:
A) that lies at an extremely high angle.
B) that is found high in the mountains.
C) where one highly permeable rock layer overlies another highly permeable rock layer, and both are dependent on
the same recharge source.
D) found on top of a local impermeable layer lying above the zone of saturation.
34) An unconfined aquifer is one that:
A) has no overlying impermeable layer.
B) has no impermeable layer beneath it.
C) has no impermeable layer either above or beneath it.
D) is unbounded laterally by geological obstacles.
35) The potentiometric surface of an artesian aquifer is:
A) the difference in elevation between the area of recharge and the area of discharge.
B) the level to which the water in the area of discharge would rise in the absence of friction.
C) the boundary between the artesian aquifer and an overlying confining layer.
D) the difference in groundwater potential between water in the area of discharge and water in the area of recharge.
36) The method used to conclusively identify the best place to drill a well is to:
A) locate sources of surface water because such sources intersect the water table.
B) survey an area's vegetation because certain plant species indicate specific depths of the water table.
C) drill test wells, because they show the depth of the water table at particular places.
D) employ the services of dowsers, because they have been proven completely reliable.
37) When water is withdrawn from a well, a cone of depression is created in which:
A) the land surface in the vicinity of the well subsides.
B) the water table in the vicinity of the well is temporarily lowered.
C) the groundwater potential in the vicinity of the well is lowered.
D) the soil within the aquifer presses inward toward the well.
38) Saltwater intrusion is most serious in which region?
A) On islands.
B) On peninsulas.
C) In heavily populated coastal areas.
D) All of the above.
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39) Grading steep slopes can enhance groundwater recharge because such a measure:
A) reduces the depth of the water table.
B) removes impermeable materials.
C) reduces the hydraulic gradient of the groundwater.
D) reduces the runoff from precipitation.
40) The desalinization of seawater is an uncommon way to relieve water shortages even in areas near the ocean
because:
A) it is usually not economically feasible.
B) sufficient quantities of water cannot be produced.
C) desalinization technology is still in its infant stages.
D) it would upset the global hydrologic cycle.
42) Which of the following statements about karst in desert regions is true?
A) Karst features in deserts indicate former times of greater precipitation.
B) High temperatures in deserts promote limestone solution.
C) High temperatures in deserts promote fracturing in limestone.
D) Thick desert soils promote limestone solution.
43) Caves found in New England and parts of eastern Canada tend to be relatively small and less extensive
primarily because:
A) the major source of precipitation is snow.
B) the groundwater is less acidic.
C) the type of limestone found there is unusually resistant to dissolution.
D) the bedrock is crystalline and contains little limestone.
44) Cross sections of speleothems reveal an ancient ice age because:
A) speleothems do not grow when a cave is overlain by a sheet of ice.
B) some of the concentric layers within a speleothem contain pockets caused by ice formation.
C) darker layers within a speleothem represent periods of colder climate.
D) speleothems produce thicker concentric layers when the cave is affected by an ice age.
45) A prominent surface feature of karst land would be:
A) rectangular drainage patterns.
B) meandering streams.
C) braided streams.
D) disappearing streams.
46) All of the following statements about disappearing streams are true EXCEPT:
A) they seldom meander.
B) they drain completely into sinkholes.
C) they present serious flooding problems when sinkholes become plugged.
D) they may return to the surface as natural springs.
47) Natural bridges form from:
A) interconnections of large speleothems.
B) spans of insoluble rock that connect sinkholes.
C) uncollapsed material between expanded and coalesced sinkholes.
D) accumulations of sediment across sinkhole lakes.
48) It is especially important to protect groundwater within cave systems from contamination because:
A) water is not filtered, and there is not enough time for microorganisms to consume contaminants.
B) the chemical constituents of limestone tend to enhance contaminants rather than degrade them.
C) pollutants accumulate so rapidly that natural cleaning mechanisms are overloaded.
D) karst groundwater often seeps upward into the soil and contaminates agricultural crops.
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ANSWER TWO (2) OF THE QUESTIONS BELOW BY MAKING A BOOKLET FOR EACH
QUESTION. BE SURE TO USE LABELED DIAGRAMS AND BRIEF CLEAR
EXPLANATIONS. THESE MUST BE DRAWN ON BLANK UNLINED PAPER.
1) Explain why groundwater is an important resource.
2) Discuss the flow rate of groundwater in terms of groundwater potential and Darcy's findings.
3) What is the relationship between local topography and bodies of surface water and the level of the water table?
4) Discuss the laws governing ownership of groundwater in the United States.
5) What causes the dissolution of limestone?
6) Describe the formation and growth of helictites, cave pearls, and cave popcorn.
7) Explain the concept of a graded stream.
8) Define the mechanisms by which streams erode their channels.
9) How do natural levees form?
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