Irrigation Engineering: Set 05

Irrigation Engineering Set 5 | Science Stoppers

1. An outlet which maintains a constant discharge irrespective of the fluctuations in the water levels of the distributary and the field channel is called: एक आउटलेट जो वितरिका (distributary) और फील्ड चैनल के जल स्तर में उतार-चढ़ाव के बावजूद निरंतर डिस्चार्ज बनाए रखता है, कहलाता है:

A) Semi-modular outlet
B) Non-modular outlet
C) Rigid module
D) Flexible module

Correct Answer: C
Explanation: A Rigid Module (like the Gibbs Module) provides a fixed discharge as long as the water levels are within a specific range. It is independent of both U/S and D/S fluctuations.

2. Match the River Training Works with their primary purpose:
1. Guide Banks | P. Protect the river banks from erosion
2. Groynes/Spurs | Q. Direct the river flow through a bridge or weir
3. Levees | R. Prevent flooding of adjacent lands नदी प्रशिक्षण कार्यों (River Training Works) का उनके प्राथमिक उद्देश्य से मिलान करें:
1. गाइड बैंक | P. नदी के किनारों को कटाव से बचाना
2. ग्रोइन्स/स्पर्स | Q. नदी के प्रवाह को पुल या वियर के माध्यम से निर्देशित करना
3. लेवीज़ (Levees) | R. आस-पास की भूमि को बाढ़ से बचाना

A) 1-Q, 2-P, 3-R
B) 1-P, 2-Q, 3-R
C) 1-R, 2-P, 3-Q
D) 1-Q, 2-R, 3-P

Correct Answer: A
Explanation: Guide banks (Bell’s banks) are used at bridge sites. Groynes are projected from banks to deflect flow. Levees (marginal embankments) are for flood protection.

3. According to Lacey, the scour depth (R) for a discharge intensity of ‘q’ (m³/s/m) and silt factor ‘f’ is: लेसी के अनुसार, डिस्चार्ज तीव्रता ‘q’ और सिल्ट फैक्टर ‘f’ के लिए स्काउर गहराई (R) क्या है?

A) 1.35 (q/f)¹/³
B) 1.35 (q²/f)¹/³
C) 0.47 (Q/f)¹/³
D) 1.21 (q/f)¹/³

Correct Answer: B
Explanation: The regime scour depth is given by R = 1.35 (q²/f)^{1/3}. If total discharge Q is used, the formula is R = 0.47 (Q/f)^{1/3}.

4. Assertion (A): Providing an intercepting drain is an effective way to control waterlogging in areas adjacent to unlined canals.
Reason (R): Intercepting drains collect the seepage water before it reaches the ground surface of the protected land. कथन (A): अनलाइन वाली नहरों के आस-पास के क्षेत्रों में जलभराव को नियंत्रित करने के लिए इंटरसेप्टिंग ड्रेन प्रदान करना एक प्रभावी तरीका है।
कारण (R): इंटरसेप्टिंग ड्रेन रिसाव वाले पानी को संरक्षित भूमि की सतह तक पहुँचने से पहले ही इकट्ठा कर लेती हैं।

A) Both A and R are true and R is the correct explanation of A
B) Both A and R are true but R is NOT the correct explanation
C) A is true but R is false
D) A is false but R is true

Correct Answer: A
Explanation: Intercepting drains are placed parallel to canals to catch lateral seepage and prevent the water table from rising in nearby fields.

5. If 10 cumecs of water is diverted from a reservoir and 7 cumecs reaches the field, what is the Water Conveyance Efficiency? यदि एक जलाशय से 10 क्यूमेक पानी मोड़ा जाता है और 7 क्यूमेक खेत तक पहुँचता है, तो जल संवहन दक्षता (Water Conveyance Efficiency) क्या है?

A) 70%
B) 30%
C) 1.42%
D) 100%

Correct Answer: A
Explanation: Efficiency ηc = (Output / Input) × 100 = (7 / 10) × 100 = 70%.

6. A groyne pointing upstream in the direction of flow is called: प्रवाह की दिशा में अपस्ट्रीम की ओर इशारा करने वाले ग्रोइन (groyne) को क्या कहा जाता है?

A) Attracting Groyne
B) Repelling Groyne
C) Deflecting Groyne
D) Sedimentary Groyne

Correct Answer: B
Explanation: Repelling groynes point upstream (usually at 60°-80°). They push the flow away from the bank where they are located. Attracting groynes point downstream.

7. If the Critical Velocity Ratio (m) is greater than 1.0, it indicates that the silt is: यदि क्रांतिक वेग अनुपात (m) 1.0 से अधिक है, तो यह दर्शाता है कि सिल्ट:

A) Finer than the standard silt
B) Coarser than the standard silt
C) Same as the standard silt
D) Absent in the water

Correct Answer: B
Explanation: m = 1.0 for standard silt of Upper Bari Doab Canal. m > 1.0 for coarser silt (requires higher velocity to prevent silting), m < 1.0 for finer silt.

8. In a Siphon Aqueduct, the water level in the drainage (stream) is: सिफन एक्वाडक्ट (Siphon Aqueduct) में, ड्रेनेज (धारा) में जल स्तर होता है:

A) Below the canal bed
B) Above the canal bed but below FSL
C) Above the canal bed such that it touches the canal bottom
D) Above the canal bed and the flow is under pressure

Correct Answer: D
Explanation: In a siphon aqueduct, the drainage HFL is above the canal bed, and the drainage water flows under siphonic pressure through the barrels.

9. Find the Consumptive Irrigation Requirement (CIR) if Consumptive Use (Cu) = 15 cm and Effective Rainfall (Re) = 3 cm. यदि उपभोगकारी उपयोग (Cu) = 15 सेमी और प्रभावी वर्षा (Re) = 3 सेमी है, तो उपभोगकारी सिंचाई आवश्यकता (CIR) ज्ञात करें।

A) 18 cm
B) 12 cm
C) 5 cm
D) 45 cm

Correct Answer: B
Explanation: CIR = Cu – Re = 15 – 3 = 12 cm.

10. Garret’s diagrams are used for the graphical design of: गैरेट आरेखों (Garret’s diagrams) का उपयोग किसके ग्राफिकल डिज़ाइन के लिए किया जाता है?

A) Lacey’s regime channels
B) Kennedy’s theory based canals
C) Gravity dams
D) Spillways

Correct Answer: B
Explanation: Garret’s diagrams provide a graphical method to solve Kennedy’s and Kutter’s equations simultaneously for canal design.

11. Meander ratio is the ratio of: मिएन्डर अनुपात (Meander ratio) किसका अनुपात है?

A) Meander length to meander belt
B) Meander belt width to meander length
C) Actual length to axial length
D) Discharge to silt factor

Correct Answer: B
Explanation: Meander ratio = Meander Belt Width / Meander Length. It helps in classifying the winding nature of the river.

12. A soil is considered ‘Saline’ if its Electrical Conductivity (EC) is: मिट्टी को ‘लवणीय’ (Saline) माना जाता है यदि इसकी विद्युत चालकता (EC) है:

A) Less than 4 mmhos/cm
B) More than 4 mmhos/cm
C) Zero
D) Exactly 1 mmhos/cm

Correct Answer: B
Explanation: Saline soils have EC > 4 mmhos/cm, Exchangeable Sodium Percentage (ESP) < 15%, and pH < 8.5.

13. Flexibility of an outlet is the ratio of: आउटलेट की लचीलापन (Flexibility) किसका अनुपात है?

A) Rate of change of outlet discharge to the rate of change of distributary discharge
B) Outlet discharge to distributary discharge
C) Water depth to silt factor
D) Depth of outlet to depth of canal

Correct Answer: A
Explanation: Flexibility F = (dq/q) / (dQ/Q). If F=1, the outlet is proportional.

14. Surcharge storage in a reservoir is the volume of water stored between: जलाशय में सरचार्ज स्टोरेज (Surcharge storage) किसके बीच जमा पानी का आयतन है?

A) Minimum pool level and Normal pool level
B) Normal pool level and Maximum pool level
C) River bed and Minimum pool level
D) Normal pool level and the spillway crest

Correct Answer: B
Explanation: Surcharge storage is temporary storage above the normal pool level during high floods, which is eventually discharged through spillways.

15. Assertion (A): Lacey’s silt factor ‘f’ increases with the increase in the average size of the silt particles.
Reason (R): Coarser particles require higher velocity to remain in suspension. कथन (A): सिल्ट कणों के औसत आकार में वृद्धि के साथ लेसी का सिल्ट फैक्टर ‘f’ बढ़ता है।
कारण (R): मोटे कणों को निलंबन (suspension) में रहने के लिए उच्च वेग की आवश्यकता होती है।

A) Both A and R are true and R is the correct explanation of A
B) Both A and R are true but R is NOT the correct explanation
C) A is true but R is false
D) A is false but R is true

Correct Answer: A
Explanation: f = 1.76 √dmm. Larger ‘d’ means larger ‘f’. Coarser silt needs more energy (velocity) to be transported, which is reflected in the silt factor.

16. A canal escape is provided to: कैनाल एस्केप (Canal escape) किसके लिए प्रदान किया जाता है?

A) Pass surplus water safely out of the canal
B) Control the silt entering the canal
C) Increase the duty of water
D) Measure the discharge

Correct Answer: A
Explanation: Escapes act as safety valves for canals, discharging excess water during sudden shutdowns or heavy rains to prevent bank breaches.

17. If 100 m³ of water is delivered to the field and 80 m³ is stored in the root zone, the Water Application Efficiency is: यदि 100 m³ पानी खेत में पहुँचाया जाता है और 80 m³ जड़ क्षेत्र (root zone) में जमा होता है, तो जल अनुप्रयोग दक्षता क्या है?

A) 20%
B) 80%
C) 125%
D) 90%

Correct Answer: B
Explanation: ηa = (Water stored in root zone / Water delivered to field) × 100 = 80%.

18. The shutter provided on the crest of a weir is used to: वियर के क्रेस्ट पर प्रदान किए गए शटर का उपयोग किसके लिए किया जाता है?

A) Raise the pond level during low flow
B) Decrease the velocity of approach
C) Prevent the piping failure
D) Filter the silt

Correct Answer: A
Explanation: Shutters are used to temporarily raise the water level above the concrete crest during dry seasons to ensure enough head for the canal.

19. A pipe outlet is an example of: पाइप आउटलेट किसका एक उदाहरण है?

A) Rigid module
B) Non-modular outlet
C) Semi-module
D) Proportional module

Correct Answer: B
Explanation: A pipe outlet discharging submerged is a non-modular outlet because its discharge varies with both U/S and D/S water levels. (Note: if it has a free fall, it becomes a semi-module).

20. The trap efficiency of a reservoir is a function of: जलाशय की ट्रैप दक्षता (trap efficiency) किसका एक कार्य है?

A) Capacity to Inflow ratio
) Silt factor
C) Length of the dam
D) Surface area of the reservoir

Correct Answer: A
Explanation: Trap efficiency decreases as the reservoir fills with silt because the Capacity/Inflow (C/I) ratio decreases.

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