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Question 1
ప్రశ్న 1
For an event in which rainfall depth P and corresponding direct-runoff depth R are known, which expression defines the event runoff coefficient C?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The event runoff coefficient expresses the fraction of rainfall depth appearing as direct runoff. It is therefore calculated as runoff depth divided by rainfall depth. Both quantities must refer to the same catchment and event. The coefficient is dimensionless when consistent depth units are used. Therefore C = R/P and Option A is correct.
వివరణ:
Question 2
ప్రశ్న 2
A storm produces 120 mm of rainfall over a catchment and the measured direct-runoff depth is 54 mm. What is the event runoff coefficient?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The runoff coefficient is the ratio of direct-runoff depth to rainfall depth. Thus C = 54/120. The resulting value is 0.45. This means that 45 percent of the storm rainfall depth appeared as direct runoff under the stated event conditions. Therefore Option B is correct.
వివరణ:
Question 3
ప్రశ్న 3
A 25 km² catchment receives a spatially averaged storm rainfall of 100 mm. If the event runoff coefficient is 0.40, what direct-runoff volume is estimated?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The estimated runoff depth is C times rainfall depth. Thus R = 0.40 × 100 = 40 mm, or 0.040 m. The catchment area is 25 million square metres. Runoff volume is therefore 0.040 × 25,000,000 = 1,000,000 m³. Hence Option C is correct.
వివరణ:
Question 4
ప్రశ్న 4
A 60 km² watershed receives 100 mm of rainfall and produces 2.4 million m³ of direct runoff. What is the corresponding runoff coefficient?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The runoff depth equals runoff volume divided by catchment area. Thus 2.4 million m³ divided by 60 million m² gives 0.040 m, or 40 mm. The rainfall depth is 100 mm. Therefore C = 40/100 = 0.40. Hence Option B is correct.
వివరణ:
Question 5
ప్రశ్న 5
Why should a runoff coefficient determined from one storm not automatically be treated as a universal constant for the catchment?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Runoff generation depends on more than catchment area. Antecedent wetness can change infiltration and available soil storage. Rainfall intensity, duration, land cover and soil condition can also change the fraction becoming runoff. Consequently an event runoff coefficient can vary significantly from storm to storm. Therefore Option A is correct.
వివరణ:
Question 6
ప్రశ్న 6
A catchment consists of 40% highly urbanized area with runoff coefficient 0.80 and 60% less-developed area with coefficient 0.30. Using area-weighted coefficients, what composite runoff coefficient is obtained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A composite coefficient can be calculated by weighting each land-use coefficient by its fractional area. The urban contribution is 0.40 × 0.80 = 0.32. The remaining area contributes 0.60 × 0.30 = 0.18. Their sum is 0.50. Therefore Option B is correct.
వివరణ:
Question 7
ప్రశ్న 7
Which method most directly determines runoff volume from an observed streamflow hydrograph at a gauging station?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Stream discharge has units of volume per unit time. Integrating discharge over time therefore yields a total volume. For storm direct runoff, base flow may first be separated if the objective is direct-runoff volume. For total catchment yield over a period, the appropriate total streamflow record can be integrated. Therefore Option A is correct.
వివరణ:
Question 8
ప్రశ్న 8
A stream maintains a discharge of 5 m³/s for exactly 2 days. What water volume passes the gauging section during this period?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Two days contain 2 × 24 × 3600 = 172,800 seconds. Volume equals discharge multiplied by elapsed time. Thus V = 5 × 172,800 = 864,000 m³. The calculation assumes the discharge remains constant at 5 m³/s throughout the period. Therefore Option C is correct.
వివరణ:
Question 9
ప్రశ్న 9
Which statement best describes a calibrated rainfall-runoff relationship used for runoff estimation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Rainfall-runoff relationships are influenced by the characteristics of the basin being studied. Historical rainfall and runoff observations are commonly used to establish or calibrate such relationships. Their reliability is generally greatest within conditions similar to those represented by the calibration data. Large extrapolations can be uncertain because catchment response may be nonlinear or change with wetness and land use. Therefore Option A is correct.
వివరణ:
Question 10
ప్రశ్న 10
A calibrated annual rainfall-runoff relation for a particular basin is R = 0.45(P - 300), where P and R are in millimetres and the relation is to be used only within its calibration range. What annual runoff depth is estimated for P = 1100 mm?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The rainfall excess above the fitted threshold term is 1100 - 300 = 800 mm. Multiplying this by 0.45 gives 360 mm. The equation is an empirical relationship for the stated basin rather than a universal physical law. Its coefficients should therefore not be transferred blindly to unrelated catchments. Hence Option B is correct.
వివరణ:
Question 11
ప్రశ్న 11
What is the main distinction between using a runoff coefficient to estimate event runoff volume and using the Rational method Qp = CiA?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Multiplying a rainfall depth by a runoff coefficient gives an estimated runoff depth. Multiplying that depth by area gives runoff volume. The Rational method instead relates rainfall intensity, area and a runoff coefficient to a peak discharge under its standard assumptions. A peak discharge is not the same physical quantity as total runoff volume. Therefore Option A is correct.
వివరణ:
Question 12
ప్రశ్న 12
A basin receives 800 mm of annual precipitation over an area of 200 km². If a simplified annual runoff coefficient of 0.35 is applicable, what annual runoff volume is estimated?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The estimated runoff depth is 0.35 × 800 = 280 mm. This is equivalent to 0.280 m. The basin area is 200 million m². The runoff volume is 0.280 × 200 million = 56 million m³. Therefore Option B is correct.
వివరణ:
Question 13
ప్రశ్న 13
Which statement best describes catchment yield at a specified river site over a year?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Yield is a volume of water associated with the flow available at a specified river or basin site over a defined period. Annual yield therefore refers to the water quantity associated with streamflow during a year. It is not the same as peak discharge, which is an instantaneous or short-duration rate. It is also not identical to rainfall because substantial hydrologic losses and storage changes occur. Therefore Option A is correct.
వివరణ:
Question 14
ప్రశ్న 14
A river has an annual mean discharge of 12 m³/s during a 365-day year. What is the corresponding annual flow volume?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A 365-day year contains 365 × 24 × 3600 = 31,536,000 seconds. Volume is mean discharge multiplied by the duration. Thus V = 12 × 31,536,000 = 378,432,000 m³. This equals approximately 378.43 million m³. Therefore Option C is correct.
వివరణ:
Question 15
ప్రశ్న 15
Annual basin yields for five years are 80, 100, 120, 60 and 140 million m³. What is the arithmetic average annual yield?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The total of the five annual yields is 80 + 100 + 120 + 60 + 140 = 500 million m³. The arithmetic mean is obtained by dividing by five. This gives 100 million m³. The average does not itself indicate how frequently a yield of 100 million m³ will be equaled or exceeded. Therefore Option C is correct.
వివరణ:
Question 16
ప్రశ్న 16
What does a 75% dependable annual yield of 120 million m³ mean?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Dependability is an exceedance or reliability concept applied to the relevant yield series. A 75% dependable annual yield is the yield equaled or exceeded with approximately 75% probability on the adopted basis. It does not mean 75 percent of the arithmetic mean. It also does not guarantee identical water availability in every individual year. Therefore Option A is correct.
వివరణ:
Question 17
ప్రశ్న 17
If both are estimated consistently from the same annual-yield distribution, which relationship is normally expected between 75% dependable yield Y75 and 50% dependable yield Y50?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A value exceeded more frequently must normally lie lower on an ordered yield distribution. The 75% dependable yield must be available in more years than the 50% dependable yield. Consequently it is generally smaller than or equal to the 50% dependable value. Higher dependable reliability is obtained by adopting a more conservative yield. Therefore Option A is correct.
వివరణ:
Question 18
ప్రశ్న 18
Using the simple interpretation of 75% dependability, approximately how many years in a 20-year period would a 75% dependable annual yield be expected to be equaled or exceeded?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Seventy-five percent of 20 years is 0.75 × 20 = 15 years. Thus the dependable yield is interpreted as being equaled or exceeded in about 15 of 20 years on a long-run statistical basis. The actual sequence of wet and dry years need not follow a regular pattern. Dependability therefore does not imply that every fourth year will necessarily fail. Hence Option C is correct.
వివరణ:
Question 19
ప్రశ్న 19
Which statement correctly distinguishes average annual yield from dependable annual yield?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Average annual yield summarizes the central magnitude of an annual-yield series through its arithmetic mean. It does not state how often that amount will be available. Dependable yield instead incorporates an exceedance probability or reliability criterion. A few very wet years can raise the average substantially above a high-dependability yield. Therefore Option A is correct.
వివరణ:
Question 20
ప్రశ్న 20
What information does a conventional flow-duration curve provide?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A flow-duration curve is formed from ranked streamflow observations. It relates discharge magnitude to the percentage of time that magnitude is equaled or exceeded. It therefore summarizes the frequency distribution of flows. Because flows are ranked by magnitude, their original chronological sequence is lost. Therefore Option A is correct.
వివరణ:
Question 21
ప్రశ్న 21
A flow-duration curve gives Q75 = 18 m³/s. What does this mean?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The subscript 75 denotes 75 percent exceedance in the stated flow-duration interpretation. Thus 18 m³/s is equaled or exceeded for about 75 percent of the period represented. The relevant days or observations do not have to be consecutive. Because 75 percent exceedance includes all values above the threshold, more than 25 percent of observations are not excluded from being greater than the value. Therefore Option A is correct.
వివరణ:
Question 22
ప్రశ్న 22
For the same stream and period of record, which relationship between flow-duration values is normally correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A discharge exceeded 90 percent of the time represents a relatively low-flow threshold. A discharge exceeded only 25 percent of the time is a considerably higher-flow threshold. Increasing the exceedance percentage therefore generally moves toward smaller discharge values. This gives Q90 ≤ Q75 ≤ Q50 ≤ Q25. Hence Option A is correct.
వివరణ:
Question 23
ప్రశ్న 23
What important information is not preserved by a conventional flow-duration curve?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Construction of a flow-duration curve requires sorting flows from high to low. Sorting removes their original time ordering. The curve therefore cannot show whether low-flow days occurred consecutively or were scattered through the record. This distinction is important for storage and drought-duration studies. Therefore Option A is correct.
వివరణ:
Question 24
ప్రశ్న 24
A water-supply requirement is 15 m³/s and a long-term flow-duration curve indicates that Q75 is 18 m³/s. Ignoring abstractions, storage limitations and other system effects, what can reasonably be inferred from the natural-flow record?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Q75 = 18 m³/s means flow equaled or exceeded 18 m³/s about 75 percent of the represented time. Since the stated demand of 15 m³/s is lower than 18 m³/s, natural flow was also at least 15 m³/s during at least that fraction of time. The statement does not prove continuous reliability during every day. Storage, diversions, environmental requirements and operational constraints would require additional analysis. Therefore Option A is correct.
వివరణ:
Question 25
ప్రశ్న 25
Twenty annual yields are ranked from largest to smallest. Under the simple '15 out of 20 years' interpretation of 75% dependability, the 15th-ranked yield is 82 million m³. What is the corresponding simple estimate of 75% dependable annual yield?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Seventy-five percent of 20 annual observations corresponds to 15 observations under the simple rank interpretation stated in the question. The 15th-largest value is given as 82 million m³. That value is therefore the simple empirical estimate requested. More formal frequency analysis may use specified plotting positions or fitted distributions, but those are not assumed here. Therefore Option B is correct.
వివరణ:
Question 26
ప్రశ్న 26
A basin has an average annual yield of 160 million m³ but a 75% dependable annual yield of 110 million m³. Which interpretation is most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Annual water availability commonly varies substantially from year to year. High-yield years can raise the arithmetic mean above values available with high reliability. A 75% dependable yield is intentionally more conservative because it must be equaled or exceeded more frequently. It is therefore entirely plausible for the dependable yield to be substantially below the average. Hence Option A is correct.
వివరణ:
Question 27
ప్రశ్న 27
Consider the following statements: I. Runoff volume can be obtained by integrating discharge over time. II. A runoff coefficient based on one storm need not remain constant for every storm. III. A 75% dependable annual yield is associated with approximately 75% exceedance of the relevant annual yield series. IV. A flow-duration curve summarizes exceedance of streamflow magnitudes but does not preserve their chronological sequence. Which option is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Statement I is correct because discharge integrated over time gives water volume. Statement II is correct because runoff coefficients vary with storm and catchment conditions. Statement III correctly expresses dependable yield in terms of exceedance or reliability. Statement IV correctly identifies both the strength and limitation of a flow-duration curve. Therefore all four statements are correct and Option D is the valid answer.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: A. C = R/P సమాధానం: A.
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Question 2 ప్రశ్న 2Answer: B. 0.45 సమాధానం: B.
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Question 3 ప్రశ్న 3Answer: C. 1.00 million m³ సమాధానం: C.
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Question 4 ప్రశ్న 4Answer: B. 0.40 సమాధానం: B.
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Question 5 ప్రశ్న 5Answer: A. It can vary with rainfall characteristics, antecedent moisture, land use, soil condition and other catchment factors సమాధానం: A.
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Question 6 ప్రశ్న 6Answer: B. 0.50 సమాధానం: B.
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Question 7 ప్రశ్న 7Answer: A. Integrating discharge with respect to time over the selected period సమాధానం: A.
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Question 8 ప్రశ్న 8Answer: C. 864,000 m³ సమాధానం: C.
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Question 9 ప్రశ్న 9Answer: A. It relates observed rainfall characteristics to runoff using catchment-specific data and should be applied with awareness of its calibration range and assumptions సమాధానం: A.
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Question 10 ప్రశ్న 10Answer: B. 360 mm సమాధానం: B.
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Question 11 ప్రశ్న 11Answer: A. The runoff-depth approach estimates a volume from rainfall depth, whereas the Rational method is primarily used to estimate peak runoff rate under its design assumptions సమాధానం: A.
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Question 12 ప్రశ్న 12Answer: B. 56 million m³ సమాధానం: B.
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Question 13 ప్రశ్న 13Answer: A. The total quantity of streamflow available at that site during the year under the stated flow conditions సమాధానం: A.
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Question 14 ప్రశ్న 14Answer: C. 378.43 million m³ సమాధానం: C.
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Question 15 ప్రశ్న 15Answer: C. 100 million m³ సమాధానం: C.
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Question 16 ప్రశ్న 16Answer: A. An annual yield of 120 million m³ is expected to be equaled or exceeded in about 75% of years under the adopted statistical interpretation సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: A. Y75 is generally less than or equal to Y50 సమాధానం: A.
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Question 18 ప్రశ్న 18Answer: C. 15 years సమాధానం: C.
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Question 19 ప్రశ్న 19Answer: A. Average yield is the arithmetic mean of annual yields, whereas dependable yield is associated with a specified probability of being equaled or exceeded సమాధానం: A.
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Question 20 ప్రశ్న 20Answer: A. The percentage of time that specified stream discharges are equaled or exceeded during the period represented సమాధానం: A.
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Question 21 ప్రశ్న 21Answer: A. A discharge of 18 m³/s was equaled or exceeded about 75% of the time represented by the curve సమాధానం: A.
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Question 22 ప్రశ్న 22Answer: A. Q90 ≤ Q75 ≤ Q50 ≤ Q25 సమాధానం: A.
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Question 23 ప్రశ్న 23Answer: A. The chronological sequence in which high and low flows occurred సమాధానం: A.
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Question 24 ప్రశ్న 24Answer: A. The natural streamflow was at least 18 m³/s, and therefore at least 15 m³/s, for about 75% of the represented time సమాధానం: A.
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Question 25 ప్రశ్న 25Answer: B. 82 million m³ సమాధానం: B.
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Question 26 ప్రశ్న 26Answer: A. Wet years raise the arithmetic average, while 110 million m³ is the more conservative yield associated with about 75% annual dependability సమాధానం: A.
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Question 27 ప్రశ్న 27Answer: D. I, II, III and IV సమాధానం: D.