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Question 1
ప్రశ్న 1
What is the primary engineering function of a spillway provided at a storage dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A spillway is a safety-related hydraulic structure used to release surplus or flood water that cannot safely be retained in the reservoir. Its capacity and arrangement help prevent reservoir level from rising above the permissible maximum level during major inflow events. This is particularly important for earth and rockfill dams because uncontrolled overtopping can rapidly erode an ordinary embankment. Spillways are distinct from low-level outlet works used for routine irrigation, water supply, drawdown, or other controlled releases. Spillway adequacy must therefore be assessed together with the design flood, reservoir routing, freeboard, and dam type. Therefore Option B is correct.
వివరణ:
Question 2
ప్రశ్న 2
Which statement correctly distinguishes an uncontrolled spillway from a controlled spillway?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
An uncontrolled spillway normally has no mechanically operated gate regulating flood discharge at its control section. Once reservoir level rises above the control crest, the discharge is governed primarily by the available hydraulic head and spillway geometry. A controlled spillway incorporates gates or similar devices that allow the effective opening and discharge to be varied. Gates can improve operational flexibility but introduce mechanical, electrical, maintenance, and operating requirements. Neither controlled nor uncontrolled operation is restricted exclusively to one particular dam material. Therefore Option C is correct.
వివరణ:
Question 3
ప్రశ్న 3
What is a principal advantage of providing gates on a spillway crest where the project conditions justify them?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Crest gates can retain reservoir water above the fixed structural crest during normal operation. When increased flood-release capacity is required, the gates can be opened to enlarge the effective flow area. This arrangement can provide useful flexibility between conservation storage and flood management. However, gates do not remove the need for design-flood estimation or reservoir routing. Gate reliability, hoisting equipment, backup power, maintenance, access, and operating procedures become important safety considerations. Therefore Option A is correct.
వివరణ:
Question 4
ప్రశ్న 4
Which description most accurately characterizes an ogee overflow spillway?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
An ogee spillway has a specially curved overflow crest and downstream profile. Its shape is developed to provide hydraulically efficient overflow under the selected design conditions. Ogee spillways are particularly compatible with concrete gravity and similar concrete overflow dams because the dam body can form the spillway section. Their capacity depends on effective crest length, total head, crest geometry, approach conditions, piers, gates, and downstream influences where applicable. The downstream portion must also be designed to withstand high velocities and safely convey the discharge to an energy-dissipation system. Therefore Option D is correct.
వివరణ:
Question 5
ప్రశ్న 5
What is the characteristic hydraulic arrangement of a chute spillway?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A chute spillway conveys water from its control structure to a lower downstream elevation through a relatively steep open channel. Flow in the chute is commonly rapid and may become strongly supercritical. The chute therefore requires suitable lining, wall height, transitions, drainage, and structural detailing. At high velocities, cavitation and aeration can also become important design considerations. Chute spillways are especially useful for conveying floodwater around rather than directly over an embankment dam. Therefore Option B is correct.
వివరణ:
Question 6
ప్రశ్న 6
Which feature most clearly distinguishes a side-channel spillway?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
In a side-channel spillway, water first passes over the spillway control crest into a channel lying generally parallel to that crest. The longitudinal discharge in the side channel increases as additional flow enters along the crest length. The accumulated flow is subsequently turned and conveyed into a chute, tunnel, or other downstream waterway. This arrangement can fit topography where sufficient crest length is available along an abutment but a conventional direct chute alignment is difficult. The characteristic parallel-flow collection channel distinguishes it from an ordinary chute spillway. Therefore Option C is correct.
వివరణ:
Question 7
ప్రశ్న 7
Which description best represents a shaft, or morning-glory, spillway?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A shaft spillway commonly has a circular or curved inlet located within or near the reservoir. Water passes over the inlet crest and enters a vertical or steeply inclined shaft. The shaft is then connected through a bend or transition to a tunnel or conduit carrying water to the downstream river. Such an arrangement can provide a compact spillway where surface space is limited. Hydraulic design must consider inlet control, shaft and tunnel capacity, vortices, aeration, pressure behavior, and debris. Therefore Option A is correct.
వివరణ:
Question 8
ప్రశ్న 8
What is the essential operating principle of a siphon spillway?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A siphon spillway contains a closed or hooded passage extending over the spillway crest. As reservoir level rises sufficiently, the passage can prime and air can be largely expelled from the flowing waterway. The resulting siphonic action allows the barrel to operate full and can produce a large discharge through a compact structure. The flow is controlled by the hydraulic head and the siphon geometry rather than by a conventional lifting gate during normal automatic operation. Adequate venting and a siphon-breaking arrangement are important for reliable termination of siphonic flow. Therefore Option D is correct.
వివరణ:
Question 9
ప్రశ్న 9
For a high earthfill dam where competent rock is available along an abutment and the spillway flow should be kept away from the embankment, which spillway arrangement commonly deserves strong consideration?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Conventional earthfill dams are vulnerable to severe erosion if floodwater flows uncontrolled over their crests and downstream slopes. A separate spillway is therefore normally provided where major flood discharge must be passed. Competent rock along an abutment can provide favorable foundation conditions for a lined chute and its control structure. The chute can convey the water around the embankment to an appropriate downstream energy-dissipation location. Final selection still depends on topography, geology, discharge, excavation, downstream conditions, and overall economy. Therefore Option B is correct.
వివరణ:
Question 10
ప్రశ్న 10
Which spillway type is often particularly compatible with a concrete gravity dam when suitable foundation and downstream energy-dissipation conditions exist?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A concrete gravity dam can often accommodate flood discharge directly over a designed portion of its concrete body. An ogee overflow section is therefore a common and hydraulically efficient arrangement for such dams. The massive concrete section can resist the structural and hydraulic forces associated with overflow when properly designed. Piers, gates, training walls, drainage, cavitation control, and downstream energy dissipation may also form part of the complete spillway system. This compatibility does not mean that every concrete gravity dam must use an ogee spillway, since site conditions can favor alternatives. Therefore Option C is correct.
వివరణ:
Question 11
ప్రశ్న 11
A dam is located in a narrow, steep-sided canyon where surface space for a long chute is restricted and a tunnel can conveniently carry floodwater downstream. Which spillway type may be particularly suitable for evaluation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A shaft spillway provides a relatively compact reservoir inlet and can therefore be advantageous where surface space is restricted. Water can descend through the shaft and then be conveyed downstream through a tunnel. This arrangement can fit narrow or steep-sided sites where constructing a long surface chute would require extensive excavation or difficult alignment. Adequate foundation conditions and a satisfactory tunnel route remain essential considerations. The design must also address vortex formation, debris, air demand, pressure conditions, and the hydraulic capacity of the shaft-tunnel system. Therefore Option A is correct.
వివరణ:
Question 12
ప్రశ్న 12
Under which topographic condition can a side-channel spillway be advantageous?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A side-channel spillway permits the control crest to be placed along an abutment or hillside where useful crest length is available. Instead of moving directly downstream normal to the crest, overflow first enters a channel that runs generally parallel to it. The collected discharge can then be turned into a chute, tunnel, or other conveyance system. This arrangement can reduce difficult excavation where a conventional direct chute alignment is restricted by topography. Hydraulic design of the side channel must account for the continuously increasing discharge along its length. Therefore Option D is correct.
వివరణ:
Question 13
ప్రశ్న 13
For an idealized uncontrolled spillway, discharge is estimated by Q = C L H^(3/2). If C = 2.10, effective crest length L = 20 m and head H = 2.0 m, what is the discharge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The supplied relation is Q = C L H^(3/2). For H = 2.0 m, H^(3/2) = 2 × sqrt(2), which is approximately 2.828. Substitution gives Q = 2.10 × 20 × 2.828. The resulting discharge is approximately 118.8 m³/s. Because the coefficient has been supplied in the problem, no external spillway-coefficient table is required. Therefore Option C is correct.
వివరణ:
Question 14
ప్రశ్న 14
An uncontrolled spillway is to pass 180 m³/s using the simplified relation Q = C L H^(3/2). If C = 2.00 and the design head is 3.0 m, what effective crest length is required?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The supplied equation can be rearranged as L = Q/[C H^(3/2)]. For H = 3.0 m, H^(3/2) = 3sqrt(3), which is approximately 5.196. The denominator is therefore 2.00 × 5.196 = 10.392. Dividing 180 by 10.392 gives an effective crest length of approximately 17.32 m. The calculation uses only the coefficient explicitly given in the question. Therefore Option B is correct.
వివరణ:
Question 15
ప్రశ్న 15
For an uncontrolled spillway following Q proportional to H^(3/2), by what factor does the discharge increase if the head rises from 2 m to 3 m while all other factors remain unchanged?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
With crest length and discharge coefficient unchanged, the discharge ratio depends only on the ratio of heads raised to the three-halves power. Thus Q2/Q1 = (3/2)^(3/2). This expression evaluates to approximately 1.837. Therefore the discharge becomes about 1.84 times its previous value. The result also illustrates that spillway discharge is more sensitive to head than a simple linear relationship would suggest. Therefore Option A is correct.
వివరణ:
Question 16
ప్రశ్న 16
What is meant by the spillway crest elevation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The spillway crest is the principal control elevation associated with overflow in an uncontrolled crest arrangement. Reservoir water must rise to the crest and then above it to develop the head that produces significant overflow discharge. The difference between reservoir water level and the effective control crest contributes to the hydraulic head used in discharge calculations. In gated spillways, the structural crest, gate opening, and operating reservoir level must be considered together rather than using an uncontrolled-crest interpretation alone. Crest elevation therefore has important implications for both conservation storage and flood routing. Therefore Option D is correct.
వివరణ:
Question 17
ప్రశ్న 17
For a given uncontrolled spillway crest length and coefficient, what happens to discharge as the water level and therefore head above the crest increase?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The hydraulic head above an uncontrolled crest is a major determinant of spillway discharge. In the standard idealized weir-type expression, discharge varies approximately with H^(3/2). Discharge therefore rises nonlinearly as reservoir level and head increase. The actual relationship can also be influenced by approach flow, crest shape, piers, abutments, submergence, and other hydraulic effects. A constant crest length consequently does not imply a constant spillway discharge. Therefore Option B is correct.
వివరణ:
Question 18
ప్రశ్న 18
Which statement best describes the engineering trade-off introduced by spillway gates?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Spillway gates allow operators to regulate the release of reservoir water and can provide greater flexibility in managing storage. They may permit conservation water to be held above the elevation of the fixed structural crest. However, gates introduce mechanical components whose failure or delayed operation can reduce available flood-release capacity. Hoists, power supplies, backup systems, access, inspection, maintenance, and operating procedures therefore become important parts of spillway reliability. Flood-routing studies are still necessary because gates cannot create unlimited discharge capacity. Therefore Option C is correct.
వివరణ:
Question 19
ప్రశ్న 19
What is the appropriate basic principle when fixing the required spillway capacity for a dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Spillway capacity is fundamentally determined from flood-safety requirements rather than from ordinary river flow alone. The applicable inflow design flood is established using the relevant hydrologic and dam-safety criteria. Reservoir routing then evaluates how inflow, storage, reservoir level, and spillway outflow interact during the event. The resulting maximum reservoir level must remain compatible with dam safety, freeboard, and structural limitations. Catchment characteristics and the required safety level therefore make spillway capacity project-specific. Therefore Option A is correct.
వివరణ:
Question 20
ప్రశ్న 20
Why is an energy dissipator commonly required downstream of a high-head spillway?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Water descending through a high-head spillway can attain very high velocity. The corresponding kinetic energy can produce severe scour if the flow is discharged directly onto an erodible riverbed or foundation. Energy dissipators reduce or redirect this energy before the flow enters the downstream channel. Depending on head, discharge, tail-water, and geology, arrangements may include hydraulic-jump stilling basins, flip buckets, or plunge pools. Energy dissipation must therefore be considered as part of the complete spillway system rather than as an unrelated downstream feature. Therefore Option D is correct.
వివరణ:
Question 21
ప్రశ్న 21
Which operational concern deserves particular attention when considering a shaft spillway at a reservoir carrying substantial floating debris?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A shaft spillway concentrates a large flood discharge into a relatively compact inlet. Floating logs, vegetation, ice, or other debris can therefore interfere with the approach flow or partially obstruct the entrance. Such blockage can reduce hydraulic capacity at the time when reliable spillway performance is especially important. Shaft spillways can also experience vortex formation and significant air-demand and pressure effects. Debris control and inlet configuration must consequently be evaluated as part of the hydraulic and operational design. Therefore Option B is correct.
వివరణ:
Question 22
ప్రశ్న 22
What happens hydraulically in the collection trough of a side-channel spillway as water enters progressively along the overflow crest?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Water enters the side channel continuously or progressively along the control crest. The longitudinal flow rate within the channel therefore increases in the downstream direction as additional overflow is collected. This spatially varied flow makes side-channel hydraulics more complex than flow in a uniform chute receiving all discharge at its upstream end. At the end of the side channel, an appropriate transition normally redirects the accumulated flow into the principal chute, tunnel, or conduit. The trough geometry must be designed to accommodate the changing discharge and associated water-surface behavior. Therefore Option A is correct.
వివరణ:
Question 23
ప్రశ్న 23
What is the function of a siphon breaker in a siphon spillway?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
After a siphon spillway becomes fully primed, the continuous water column can sustain a substantial discharge. The siphon must cease operating when reservoir level falls to the intended lower control level. A siphon breaker admits air into the passage and destroys the continuous siphonic water column. This stops full siphonic action and helps prevent excessive reservoir drawdown. Proper venting and breaker design can also reduce undesirable cycling, slugging, vibration, and unstable hydraulic operation. Therefore Option D is correct.
వివరణ:
Question 24
ప్రశ్న 24
Which group of factors is most appropriate when selecting a spillway type for a new dam?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Spillway selection is a multidisciplinary engineering decision rather than a choice based on one parameter. Design discharge and available head influence the hydraulic size and form of the spillway. Dam type, valley topography, geology, foundation quality, and available space determine which layouts can be constructed safely. Debris, sediment, downstream energy dissipation, construction access, operational reliability, maintenance, and cost can substantially alter the preferred alternative. Several feasible arrangements should therefore normally be compared before the final spillway type is selected. Therefore Option C is correct.
వివరణ:
Question 25
ప్రశ్న 25
Consider the following statements about spillways: I. An ogee spillway is well suited to overflow sections of concrete dams. II. A chute spillway can convey flow around an embankment dam through a separate lined channel. III. A side-channel spillway initially collects overflow in a channel approximately parallel to its crest. IV. A shaft spillway can be advantageous where narrow steep topography favors a compact inlet connected to a tunnel. Which option is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Statement I is correct because ogee overflow sections are particularly compatible with concrete dams capable of safely carrying overflow. Statement II is correct because a separate chute can route floodwater around an embankment rather than over ordinary earth or rockfill. Statement III correctly describes the defining initial flow arrangement of a side-channel spillway. Statement IV is also correct because a shaft spillway can provide a compact intake connected to a tunnel where steep, confined topography favors that arrangement. Each statement reflects a standard spillway configuration or selection consideration rather than a location-specific rule. Therefore all four statements are correct and Option B is the valid answer.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: B. To safely pass surplus and flood water so that the reservoir does not rise to an unsafe level and overtop the dam సమాధానం: B.
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Question 2 ప్రశ్న 2Answer: C. In an uncontrolled spillway the discharge is governed principally by water level and spillway geometry, whereas a controlled spillway uses gates or other mechanical controls to regulate discharge సమాధానం: C.
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Question 3 ప్రశ్న 3Answer: A. They permit regulation of releases and can allow conservation storage to be maintained while providing large discharge capacity when the gates are opened సమాధానం: A.
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Question 4 ప్రశ్న 4Answer: D. An overflow crest having a curved downstream profile shaped to carry high-velocity flow efficiently సమాధానం: D.
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Question 5 ప్రశ్న 5Answer: B. Water passes over a control structure and is conveyed downstream through a steep open channel or chute సమాధానం: B.
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Question 6 ప్రశ్న 6Answer: C. Water passing over the control crest initially enters a channel running approximately parallel to the crest before being turned into the main discharge conveyance సమాధానం: C.
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Question 7 ప్రశ్న 7Answer: A. A spillway in which water enters around a circular or curved crest and passes into a vertical or steep shaft connected to a downstream conduit or tunnel సమాధానం: A.
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Question 8 ప్రశ్న 8Answer: D. After suitable priming, a closed passage can flow full under siphonic action and discharge substantially more water than ordinary free overflow through a comparable opening సమాధానం: D.
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Question 9 ప్రశ్న 9Answer: B. A separate lined chute spillway founded along the abutment సమాధానం: B.
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Question 10 ప్రశ్న 10Answer: C. An ogee overflow spillway incorporated into part of the concrete dam సమాధానం: C.
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Question 11 ప్రశ్న 11Answer: A. Shaft spillway connected to a tunnel సమాధానం: A.
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Question 12 ప్రశ్న 12Answer: D. Where a long overflow crest can be accommodated along an abutment or hillside but direct downstream flow normal to the crest is restricted సమాధానం: D.
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Question 13 ప్రశ్న 13Answer: C. Approximately 118.8 m³/s సమాధానం: C.
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Question 14 ప్రశ్న 14Answer: B. Approximately 17.32 m సమాధానం: B.
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Question 15 ప్రశ్న 15Answer: A. Approximately 1.84 సమాధానం: A.
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Question 16 ప్రశ్న 16Answer: D. The control elevation at which water begins to pass over or through the spillway under the relevant uncontrolled-crest concept సమాధానం: D.
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Question 17 ప్రశ్న 17Answer: B. Discharge increases nonlinearly, approximately with H^(3/2) for the standard idealized weir-type relation సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: C. Gates provide greater operational control but introduce dependence on reliable mechanical equipment, operation, maintenance, power or backup systems సమాధానం: C.
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Question 19 ప్రశ్న 19Answer: A. The spillway and applicable reservoir routing should safely accommodate the prescribed design-flood condition without allowing an unsafe reservoir level or dam overtopping సమాధానం: A.
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Question 20 ప్రశ్న 20Answer: D. To reduce excessive kinetic energy before the flow reaches an erodible downstream channel or foundation సమాధానం: D.
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Question 21 ప్రశ్న 21Answer: B. The inlet can be vulnerable to blockage or disturbed approach flow, so debris behavior and inlet protection must be evaluated సమాధానం: B.
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Question 22 ప్రశ్న 22Answer: A. The trough discharge generally increases along its length as additional overflow enters, requiring a transition to collect and redirect the combined flow సమాధానం: A.
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Question 23 ప్రశ్న 23Answer: D. To admit air at the appropriate level so that siphonic action is broken and excessive reservoir drawdown or unstable operation is avoided సమాధానం: D.
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Question 24 ప్రశ్న 24Answer: C. Design discharge, dam type, valley topography, geology and foundation, available space, hydraulic head, debris and sediment conditions, energy dissipation, constructability, operation, reliability, and economy సమాధానం: C.
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Question 25 ప్రశ్న 25Answer: B. I, II, III and IV సమాధానం: B.