This short test consists of 15 questions and is designed to measure the users’ general level of understanding for some basic terms and some processes controlling landform development. When taken in conjunction with the POST-TEST it will allow the WILSIM designers to determine how effective the model is as an educational tool. If you realize you answered an earlier question incorrectly from information in later questions, please do not go back to change your answer as that will bias the result for the evaluating what you learned from the model (don’t be bothered by wrong answers).

1. What is the definition of “Runoff”?

A. Water flowing across the land surface (overland flow) during or after a rainfall event.
B. Water infiltrating into the soils or porous rock at the land surface during a rainfall event.
C. �Rain drop splash� that erodes the land surface.
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2. Can erosion of the land surface by flowing water occur if there is not enough rainfall to
produce runoff?.

A. Yes
B. No
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3. What is necessary in order for Runoff to occur across the land surface?

A. Rainfall events must be slow and gentle such that all precipitation infiltrates or soaks into the
land surface or soils.
B. The duration of a rainfall event must be long enough, or produce a sufficient volume of
precipitation to saturate the soils or rock at the land surface such that the excess water will flow
overland (across the land surface).
C. Runoff is only possible if the land surface is completely impermeable to rainfall water (it won’t
let any water infiltrate downward into the soil or rock).
D. Runoff is only possible after torrential downpours of rain.

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4. What is the definition of a drainage network or drainage system?

A. A single river channel that flows across the land surface.
B. A series of short unconnected stream segments or gullies that can be seen along a sloping land
C. An integrated branching arrangement of smaller streams joining together to feed larger
streams that then feed one or more main river channels.
D. A random arrangement of streams that may or may not connect and that flow in seemingly
random directions.

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5. How long does it take a complex integrated drainage system such as those seen on the
surface of the Earth and Mars to develop?

A. The entire drainage system can develop within a few years.
B. The entire drainage system can develop in short periods of time, essentially with in the time
frame of a human life span.
C. They can develop over the time span of a few centuries.
D. They develop over long periods of geologic time, from thousands to millions of years.

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6. Concerning the time frame over which drainages develop, why are numerical models
such as WILSIM so valuable?

A. They can compress time so that during a brief model run you can observe the evolution of a
drainage system that would take place over long periods of geologic time.
B. They allow you to explore and appreciate the effects of different factors on landform
evolution by setting different parameter values
C. They allow you to study the evolution of a drainage system in front of computer thus
eliminate the need to do field work
D. Both A and B.

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7. When flowing water erodes the land surface to create a drainage network, do these
drainages always develop at the same rate everywhere in nature or in a computer

A. Yes.
B. No.

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8. What do you think the best definition for �erodibility� would be?

A. The degree to which a surficial material is resistant to erosion by flowing water. Some rock
types and soils are easily eroded and some are very resistant to erosion.
B. The rate at which streams transport eroded sediments down slope or down stream.
C. The degree of steepness for slopes and stream channels in a drainage system
D. The change in slope from one portion of a drainage to another

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9. The term �Tectonics� refers to which of the following?

A. The form of an entire drainage basin.
B. The slope of the land surface.
C. The process by which drainages form
D. Deformation of the Earth’s crust and surface which serves to create changes in land surface
slope (such as the formation of mountains and plateaus)

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10. Which of the following do you think would be the primary variable that controls the
rate of drainage network development?

A. Climate; including the amount of rainfall and the vegetation cover.
B. Tectonics.
C. The durability of the surface rock or soil and how easily it can be eroded.
D. The steepness of the slope over which the streams flow and erode.
E. All of the above are primary or important variables.

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11. WILSIM can also simulate the affects of climate change upon drainage form or
morphology over time (i.e., initially dry then evolving into a wetter climate or vice
versa). How do you think climate change would affect drainage morphology?

A. It would not affect the morphology, only the rate at which the drainage develops.
B. Because the rate at which material is transported downslope to the developing stream
changes as climate changes, the morphology of the drainage as well as the rate of development
will change.

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12. How do numerical (computer) models simulate drainage development?

A. The models faithfully quantify every natural process involved in drainage development
through a combination of complex mathematical equations for every process.
B. Most models use simple laws for effective runoff and mass transfer that create drainage
systems that mimic those seen in nature.
C. After analyzing the geometry of existing drainages in nature, most models recreate that
drainage development from simple equations that produce geometric branching patterns. There
is no concern for the actual natural processes involved.
D. The models use equations to force runoff and erosion in specific directions that eventually
produce a drainage pattern.

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13. Define Cross Section in a geographic sense.

A. The statistical distribution (or histogram) of the elevation measurements for many or all
points in a land surface grid.
B. A profile of the elevation along a specific line across the land surface grid.
C. The general surface slope or change in elevation from one point on a land surface grid to

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14. What is a Hypsometric Curve?

A. A nondimensional curve that essentially describes the relative proportion of a watershed that
lies at or above a given height relative to its total elevation range .
B. The longitudinal profile of elevation along a major stream from its source (highest elevation)
to its mouth (lowest elevation).
C. A measurement of the total volume of sediment eroded from one part of a basin and
deposited in another part.
D. A measure of the sinuosity of a stream channel (measures how curvy the stream channel is).

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15. Where in the landscape do you think the deposition (accumulation of eroded and
transported sediments) would most unlikely to occur?

A. In places where the slope is very steep.
B. In places where the slope is very gentle.
C. In places where there is a change in slope from steep to gentle.
D. In places where the stream enters an open waterbody such as lake or ocean.