Question Paper: Irrigation Engineering Question Paper - Dec 17 - Civil Engineering (Semester 7) - Mumbai University (MU)
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## Irrigation Engineering - Dec 17

### Civil Engineering (Semester 7)

Total marks: 80
Total time: 3 Hours
INSTRUCTIONS
(1) Question No.1 is compulsory.
(2) Attempt any three questions from remaining five questions.
(3) Assume any suitable data where ever required.
(4) Figures to the right indicate full marks.

Q1) Attempt any four:

• a) Define irrigation. What is the necessity of irrigation?
• b) Explain the terms: aquifer, aquiclude and aquifuge.
• c) Describe various methods of computing average rainfall over a basin.
• d) Explain the term 'storage coefficient' and 'coefficient of transmissibility'.
• e) Explain Canal Lining.

(20 marks)

2(a) What are the factors affecting Run-off. What are various method of computing run-off? Explain any one method: (10 marks)

2(b) A canal takes off a reservoir to irrigate the areas given below. 40% of the water required for irrgation is assumed to be available directly from precipitation. Channel conveyance losses are 15%. Reservoir losses are 10%. What would be the capacity of reservoir needed?(The reservoir to be filled only once a year)

Crop Base period (days) Duty at the field (ha/cumec) Area under crop (ha)
Wheat 140 1700 400
Sugarcane 320 800 600
Rice 120 900 300
Cotton 220 1200 1200
Bajra 100 1200 600

(10 marks)

3(a) Explain various types of Rain-gauge with neat sketches. (10 marks)

3(b) Find the ordinates of a storm hydrograph from a 3hr storm with rainfall of 2, 6.75 and 3.75 cm during subsequent 3 hr intervals. The ordinates of hydrograph are given in the following table:

Hours 3 6 9 12 15 18 21 24 3 6 9 12 15 18 21 24
Ordinates of Unit hydrograph (cumec) 0 110 365 500 390 310 250 235 175 130 95 65 40 22 10 0

Assume an initial loss of 5 mm, infiltration index of 2.5 mm/hr and base flow of 10 cumecs.

(10 marks)

4(a) Derive an equation for discharge from a well in an unconfined aquifier. (10 marks)

4(b) Explain various types of reserviors. What do you understand by multipurpose reservoir? (10 marks)

5(a) A rectangular masonry dam is 3mt at the base. Compute the maximum permissible height H (a) when no tension is permissible, and (b) when the factor of safety against sliding is 1.5. Given the following: i) $\mu$= 0.5, ii) density of masonry =24 times the of water, and iii) c=1. What will be corresponding values of H if uplift is neglected? (10 marks)

5(b) Discuss the causes of failure of earth dams. (10 marks)

Q6) Write short notes on following:

• a) Hydrologic Cycle and Types of Precipitation
• b) Silt extractor and silt ejector
• c) Cross Drainage Work
• d) Reservoir Planning. (20 marks)