1 Multiple Choice Questions
For most questions, tick answers which you think are âTrueâ or âCorrectâ. This may range from zero to all answers. Some cases will specify the number of answers, and some will ask you to pick out an incorrect statement. It is requested that you think carefully before looking up the answers. Please also be aware that in hydrology differences tend to be âshades of greyâ rather than black and white. We hope that you find such questions a useful vehicle for fruitful discussion with your lecturers rather than outrage that the authors are so incorrect. The answers provide a brief commentary on the logic.
Units
1. A megalitre denotes a million litres. Which abbreviation is correct for this amount of water?
A. ml
B. MLi
C. ML
D. mL
2. 20 ML ha-1, as rainfall, is the same as which of the below?
A. 1 mm of rain
B. 100 mm of rain
C. 1000 mm of rain
D. None of the above
3. In the older unit of âpointsâ of rain, there are 100 points to the inch. One inch is 25.4 mm. Hence 20 points of rain is about equivalent to which of the answers below?
A. 1 mm
B. 5 mm
C. 100 mm
D. None of the above
Dimensions
4. A fundamental division in science is mass [M], length [L], and time [T]. Most (but not all) physical quantities can be ascribed dimensions such as force [MLT-2], representing the product of mass [M] by acceleration [LT-2]. Which of the following attribution of dimensions to hydrologic variables is correct?
A. Rainfall intensity [L3T-1]
B. Streamflow [L3T-1]
C. Rate of evaporation [L2T-1]
D. Volume of channel storage per unit length of channel [L3]
Strahler Ordering
5. One of the statements about Strahler order notation used for classifying waterways is incorrect. Which one?
A. The order assigned will depend on the diligence of map-makers in showing smaller streams
B. Major rivers such as the Mississippi, Danube, or the Amazon will be sixth-order or higher
C. Headwater streams originating on farms are going to be first or second-order
D. All water courses can be assigned a unique Strahler order
6. Which two of the following statements are correct about Strahler ordering of watersheds?
A. When a lower-order stream joins a higher-order stream, the order of the resulting stream increases by one
B. When a lower-order stream joins a higher-order stream, the order of the resulting stream stays the same
C. When two streams of the same order join, the order of the resulting stream increases by one
D. By definition, streams of the same order cannot join
7. Using Strahler ordering, a third-order stream is joined by two second-order streams and three first-order streams. The new stream is then?
A. Second-order
B. Fourth-order
C. Third-order
D. Fifth-order
E. None of the above
Hydrographic Measurement
8. The functions of a weir pond behind a measurement section are which of the following?
A. To allow water to approach the measurement section with a minimum velocity
B. To conserve the biota of a stream
C. To reduce turbulence at the point of measurement
D. To reduce the noise of the water outflow
E. To give the water enough height to allow it to fall free of the measurement cross-section
9. Measurement weirs are a favourite method of gauging small, upland streams. A âstream-ratingâ is a 1 to 1 relation between flow through a measurement weir and height of water above the notch. Many factors may lead to a deviation from such a relationship. One in the list below should not affect the rating â which one?
A. Water temperature
B. Sediment in the water
C. Aeration status of the water
D. Changes in the weir pond
E. Changes in the stream channel below the weir
10. The concept of a âhydrologic yearâ is sometimes used in hydrologic data analysis with the start of the year somewhere near the end of summer. Which listed advantages below are correct?
A. With this division of the year, there is less correlation between what happens in a given year with what happened in the preceding year because the watershed soil moisture is usually close to minimum
B. It sits better with the annual political cycle of many countries
C. It allows a better pairing of annual rainfall with annual streamflow
D. It best matches the annual irrigation cycle in many countries
E. Judicious choice allows âmeshingâ with the financial year of many countries
11. A diurnal variation is a characteristic stream flow variation with a 24-hour cycle. Which of the following statements are correct?
A. In a non-snow watershed, transpiration by trees will often give a diurnal variation with a day-time minimum and a night-time maximum
B. Diurnal variations are a major periodic component of the hydrologic cycle.
C. In a watershed with snow cover, the melting of snow by the sun will give a diurnal variation with a day-time maximum and a night-time minimum
D. Diurnal variations in streamflows are often obscured by the bi-diurnal tidal cycle associated with the passage of the moon over the earthâs surface
E. Diurnal variations are only found in first and second-order streams
F. They are sometimes referred to as Diehl variations
12. Consider water travelling across the earthâs surface, with the lower part of the water body in contact with the earth and in equilibrium (i.e. not falling). What is about the fastest documented speed that the water will travel at?
A. 10 kph
B. 30 kph
C. 70 kph
D. 100 kph
E. 200 kph
13. Which three of the following are necessary to develop a stream rating for hydrographic purposes?
A. A method of accurately measuring the volumetric rate of flow of a stream at a given time
B. A good working knowledge of Manningâs Equation, its errors, and how it is applied
C. A local measure of water height based on a permanent and accessible reference point
D. A good working knowledge of Bernoulliâs Equation
E. A stable cross-section which does not have discontinuities in it
F. A method of smoothing the flow to avoid turbulence
Soil Moisture and Vadose ...