Q&A Hero

Q: Match the type of sediment load to the correct definition. A) Larger sediments that bounce, roll, or slide along the bottom B) Ions in solution that are dispersed throughout the flow C) Fine sediments that are held up by the water and carried throughout the water column 1. Dissolved Load 2. Bed Load 3. Suspended Load

Q: What is the difference between a floodplain and a stream terrace?

Q: Which type of channel (bedrock or alluvial) will have meandering streams?

Q: If clay particles are smaller than silt particles, why is it harder for moving water to pick up clay?

Q: What are three methods a stream can use to erode bedrock?

Q: What is saltation and why would a particle saltate?

Q: Over oceans, rates of evaporation exceed those of precipitation. In spite of this, sea level does not drop. Explain why this is the case.

Q: When will the most runoff be generated: at the beginning of a series of storms or at the end?

Q: Define evapotranspiration.

Q: Levees are artificial, not natural formations.

Q: In a series of stream terrace levels, the oldest terrace is the one that is lowest in elevation.

Q: Point bars are locations where erosion occurs whereas cutbanks are locations where deposition occurs.

Q: Streams carry most of their sediment load in the form of suspended load.

Q: As stream velocity slows, the smallest particles get deposited first.

Q: When discharge increases, the flow velocity will increase. However, the width and depth of the stream will decrease because the stream downcutting.

Q: Maximum velocity occurs when the stream is at the bankful stage.

Q: The Nile River in Africa is a stream.

Q: Running water is the single most important erosional agent sculpting Earth's land surface.

Q: When precipitation falls, water may not immediately soak in, run off, or evaporate.

Q: The hydrologic cycle is off-balance because more liquid is brought in via comets and meteorites each year.

Q: Which of the following scenarios represents the best nonstructural approach to flood control? A) Building an artificial levee two feet taller than the highest recorded flood B) Managing a floodplain to limit development in sensitive areas C) Paving the floodplain to increase the velocity of floodwaters D) Creating a series of dams and reservoirs to store floodwater and release it slowly over time

Q: Why are urban areas susceptible to flash floods? A) Oil, gasoline, and other auto fluids repel more water into the stream system B) City sewers promote flooding of city streets and parking areas C) A high percentage of the surface area is covered with cement, asphalt, and other impervious materials D) Construction materials promote rapid absorption of precipitation, which puts excess water into the stream system

Q: A(n) ________ flood is most often associated with northward-flowing rivers in the Northern Hemisphere because the upstream stretches of the river will thaw before the downstream. A) ice-jam B) regional C) flash flood D) dam-failure

Q: A(n) ________ flood will occur when an engineered structure fails and releases large quantities of stored water. A) ice-jam B) regional C) flash flood D) dam-failure

Q: What is a flood? A) When dry weather results in a high discharge B) When discharge in a river exceeds the river's capacity C) When a dam is constructed and forces sedimentation D) When changes in gradient result in the abandonment of meander loops

Q: How many subdeltas have been formed by the Mississippi River in the last 6,000 years? A) 6 B) 2 C) 5 D) 7

Q: ________ are flat areas along streams that are created by the deposition of alluvium and is subject to periodic inundation. A) Terraces B) Floodplains C) Riffles D) Bars

Q: A(n) ________ stream is a stream that is in equilibrium and is neither eroding or depositing material, but simply transporting it. A) graded stream B) braided stream C) alluvial stream D) bedrock stream

Q: What is the ultimate base level? A) Continental Divide B) A basalt flow beneath softer sedimentary rocks C) Sea level D) The bottom of a waterfall

Q: What is base level? A) The highest elevation streams can be found. B) The downward limit of erosion. C) The transition from a straight channel stream to a meandering stream. D) The gradient line along the longitudinal profile of the stream.

Q: Which of the following locations is a likely place to find a braided stream? A) Flowing across a stream delta B) Flowing across a desert C) Flowing through a karst region D) Flowing from the terminus of a glacier

Q: A ________ stream consists of a complex network of converging and diverging channels that weave around channel bars. A) straight channel B) meandering stream C) braided stream D) bedrock channel

Q: Which of the following is not one of the three basic stream channel morphologies? A) Straight channel B) Meandering stream C) Braided stream D) Bedrock channel

Q: In which part of a stream's course would one typically find bedrock channels? A) Headwaters B) At confluences C) Mouth D) In a delta

Q: What is the term for sediment deposited by streams? A) Fluvium B) Colluvium C) Alluvium D) Talus

Q: During what periods would streams see the greatest erosion and transportation of sediment? A) Floods B) Droughts C) When frozen D) When dammed

Q: In terms of competence, if the velocity of the stream triples, the impact force of the water will increase ________ times. A) two B) three C) nine D) eighteen

Q: ________ is a measure of a stream's ability to transport particles based on size rather than quantity. A) Corrosion B) Capacity C) Competence D) Carbonate

Q: ________ is the maximum load of solid particles a stream can transport per unit time. A) Corrosion B) Capacity C) Competence D) Carbonate

Q: Which part of a stream's sediment load moves the slowest? A) Bed load B) Dissolved load C) Suspended load

Q: Which of the following particle sizes is most likely to make up a stream's suspended load? A) Gravel B) Clay C) Sand D) Silt

Q: ________ occurs when a rock is gradually dissolved by flowing water. A) Abrasion B) Corrosion C) Quarrying D) Exfoliation

Q: Which of the following beds would be easiest for a stream to erode? A) Lined with gravel and cobbles B) Bedrock C) Lined with sand and gravel D) Lined with silt

Q: What is the mouth of a stream? A) The location where one stream flows into another body of water B) The location where streamflow begins C) The location where streamflow evaporates D) The location where streams diverge into distributary channels

Q: How will channel velocity change along the longitudinal profile of a stream? A) Velocity will remain constant for the entire length of the stream B) Velocity will start high and gradually decrease toward the mouth due to increasing discharge downstream C) Velocity will start low and gradually increase toward the mouth due to increasing discharge downstream

Q: What is the longitudinal profile? A) The cross-sectional area perpendicular to the direction of flow B) The cross-sectional area from the headwaters to the mouth C) The slope of the stream channel from headwaters to the mouth D) The probability of a specific stream discharge occurring in a given year

Q: What is the wetted perimeter of a stream? A) That part of a streambed that contains the strongest current B) Where the stream is incising on the outside of a meander loop C) Where deposition occurs in an abandoned stream channel D) The amount of flow in contact with the banks and bed of the channel

Q: What will happen to the water level in the stream if the water table is below the level of the stream channel? A) The stream will lose water to the groundwater system. B) The stream will gain water from the groundwater system. C) The level of water in the stream will remain constant.

Q: Streams generally receive their water from two sources. What are those two sources? A) Lakes and meteorites B) Meteorites and comets C) Overland flow and groundwater D) Groundwater and evaporation

Q: Which of the following is not one of the three zones of a river system? A) Sediment Capacity Zone B) Sediment Transport Zone C) Sediment Deposition Zone D) Sediment Production Zone

Q: ________ is the area at the headwaters of a stream where most of the sediment is derived. A) Sediment Production B) Sediment Transport C) Sediment Deposition D) Sediment Load

Q: The ________ is an elevational point that divides an entire continent into large drainage basins. A) Appalachian Mountains B) Continental Divide C) Watershed D) Sediment production zone

Q: What is the geologic definition of a stream? A) A river of water that carries large volumes of water and has many tributaries B) A stagnant body of water with little current and low oxygen content C) A large lake system D) A channelized body of water flowing down gradient

Q: What percentage of Earth's water is in the form of seawater? A) 2.15% B) 97.2% C) 0.62% D) 0.03%

Q: The ________ describes the path water takes as it moves between the land, the ocean, and the atmosphere. A) Hydrologic Cycle B) Oxygen Cycle C) Rock Cycle D) Matter State Cycle

Q: What is infiltration? A) The transition from liquid to gas as a result of increases in temperature B) Plants taking in water C) Water soaking into the ground D) Water running off the surface and entering a channel

Q: Central Wisconsin and south-central Minnesota both have regions with the potential for landslides. However, neither of these locations is located in mountainous areas. Why might landslides occur in these specific regions? A) Agriculture has destabilized the landscape B) Permafrost in the region is thawing C) These locations have steep bluffs along rivers D) The landscape has experienced tectonic uplift

Q: Why might West Virginia have the landslide risk that it does? A) Appalachian Mountains B) Agricultural activities C) Volcanic eruptions D) Permafrost

Q: What is the risk for landslides in West Virginia? A) Very high potential B) High potential C) Moderate potential D) Low potential

Q: Assume this house is located in central Alaska. What did this house do to the local landscape to end up so misaligned? A) The house shifted because of a mudflow. B) The weight of the house generated a debris flow. C) A rockfall knocked the house off its foundation. D) Heat from the house melted the permafrost below.

Q: In which direction is mass wasting occurring in this image? (Note: The perspective is from the side.) A) From top to bottom B) From left to right C) From bottom to top D) From right to left

Q: Identify the mass-wasting event in this image. A) Slide B) Lahar C) Mudflow D) Earthflow

Q: Which one of the following locations would be most likely to have the mass wasting process visible here? (Note: The region is underlaid by permafrost.) A) Siberia B) Colorado C) Japan D) Kansas

Q: Assuming this location is near the Arctic Circle, what kind of mass wasting is visible in this image? A) Mudflow B) Creep C) Solifluction D) Rockslide

Q: Identify the mass-wasting event in this image. A) Mudflow B) Creep C) Solifluction D) Rockslide

Q: Identify the mass-wasting event in this image. A) Solifluction B) Lahar C) Mudflow D) Slump

Q: Identify the mass-wasting event in this image. A) Fall B) Lahar C) Debris flow D) Slump

Q: How did the debris from the Gros Ventre Landslide of 1925 lead to another disaster in the same region in 1927? A) Loose debris resulted in a mudflow. B) The mass movement of sediment contaminated drinking water. C) The debris blocked the river, creating a lake that later burst. D) The debris mixed with river water to create a lahar.

Q: How did the underlying geology contribute to the Gros Ventre Landslide of 1925? A) Rains saturated the sandstone and clay that make up the slope. B) Creep weakened the sandstone making up the slope. C) Vegetation was removed from the slope. D) The river that flowed through the valley dissolved the limestone.

Q: Identify the mass-wasting event in this image. A) Fall B) Rockslide C) Debris flow D) Slump

Q: You are driving along a mountain highway built into the side of the mountain. The rock layers making up the slope are oriented parallel to the slope. What are three ways that the slope could be stabilized to reduce the likelihood of landslides?

Q: How can road construction in mountainous areas exacerbate mass wasting?

Q: Compare and contrast earthflows and debris flows.

Q: What geologic factors contributed to the severity of the Gros Ventre Landslide of 1925?

Q: Evaluate the statement, "All lahars are mudflows, but not all mudflows are lahars."

Q: Compare and contrast rotational slides and translational slides.

Q: What role does fire play in making mass wasting more severe during subsequent rains?

Q: Imagine you are at the beach, building a sandcastle. Dry sand cannot hold a form, so the addition of water is necessary to build the castle. However, too much water will destroy the sandcastle and cause the sand to flow away in a slurry. This is similar to the role pore water has on sediments in a slope. What role does water play to maintain a slope? What role does water play to cause mass wasting of the slope?

Q: The great multimillionaire Rich Mahn is building a new mansion on a steep bluff overlooking a languid river below ... or, at least he could look over the river if it weren't for all the trees in the way. Whipping out his cell phone, he calls a local landscaping company and has all of the trees ripped out and the steep slope smoothed back into place. Several months later, Rich is making another phone call, this time to a construction company. It seems that the bluff is eroding away at an alarming rate and the ground that his new house is sitting on is being undermined. What event(s) led to the mass wasting at Rich's house and why?

Q: Match the mass wasting process with the correct definition. A) Gradual movement of sediment due to repeated freezing and thawing B) Soil saturated with water flows downslope in permafrost areas C) Material moves as an intact mass along a curved slip plane D) Mixture of soil, regolith, and large quantities of water E) Flow of water and volcanic materials downslope F) Material moving as an intact mass along a flat slip plane 1. Lahar 2. Creep 3. Solifluction 4. Rockslide 5. Slump 6. Debris Flow