# GTU last year question papers -BE- Sem-VIIth -Irrigation Engineering -Nov/Dec-2011

GTU last year question papers

GUJARAT TECHNOLOGICAL UNIVERSITY

BE SEM-VII Examination-Nov/Dec.-2011

Subject code: 170602

Subject Name: Irrigation Engineering

Instructions:

1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

Q.1 (a) Explain the procedure of designing an irrigation channel

with Kennedy’s theory, when Q, N, m and S are given.

(b) Explain the terms (i) Duty (ii) Delta and (iii) Base period.

Derive the relation between Duty, Delta and Base period.

Q.2 (a) Describe the method of design of a lined canal.

(b) Explain Khosla;s method of independent variables.

OR

(b) Write the design features for Boarder Strip Flooding

irrigation method.

Q.3 (a) Describe the following irrigation methods with sketches

(i) Check basin flooding method.

(ii) Drip irrigation method

(b) (i)Find the time required to cover an area of 0.1 hectares

when a tube well is discharging at the rate of 0.  cumec

for irrigating rabi crop. Average depth of flow is expected

to be 7.5 cm. Average infiltration rate for the soil may be

taken as 5 cm/hour.

(ii) Furrow 100m long and 1m apart having longitudinal

slope of 0.3 percent are initially irrigated by a non-erosive

stream for 80 minutes. The stream size is then reduced to

40% and continued for another 35 minutes. Determine the

average depth of irrigation.

OR

Q.3 (a) Describe the method of designing an irrigation canal based

on Lacey’s theory.

(b) Using Kennedy’s theory, design a channel section for the

following data:

Discharge, Q=25 cumec, Kutter’s N=0.0225,

Critical velocity ratio, m=1, Side slope =1/2:1 and

Bed slope, S=1/5000

Q.4 (a) (i) Explain the term ”Diversion Head Work” and clearly

mention its different functions.

(ii) Explain Bligh’s Creep Theory in details.

(b) A canal takes off from a reservoir to irrigate the areas as

shown in the Table below. 40% of the water required for

irrigation is assumed to be available directly from

precipitation. Channel conveyance losses are 15%.

Reservoir losses are 10%. What would be the capacity of

the reservoir needed? (The reservoir to be filled only once a

year.)

Crop Base period

(days)

Duty at field

(ha/cumec)

Area under

Crop (ha)

Wheat 120 1800 500

Sugarcane 320 800 600

Rice 120 900 300

Cotton 200 1400 1200

Bajra 100 1200 50 0

OR

Q.4 (a) State and explain the cause of failure of Structure founded on permeable soil.

(b) A weir has a solid horizontal floor length of 50 m with two

lines of cutoff 8 m depth, below the riverbed at its two

ends. The floor thickness is 1 m at the upstream end and 2

m at the downstream end, with its upper level being in

flush with the river bed. For an effective head of 5 m over

the weir, calculate the uplift pressure at the two inside

corner points (junction of bottom of floor with the cutoff)

and also exit gradient.

Q.5 (a) Describe with the help of sketches various types of Crossdrainage

works.

(b) (i) What do you understand by a fall in canal? Why it is

necessary?

(ii) What are the causes of water logging?

OR

Q.5 (a) What is weir? How does it differ from a barrage structure?

Give relative advantages and disadvantages with their

salient features.

(b) (i) What are the functions of a canal head regulator?

(ii) Explain the terms with a sketches wherever applicable

(1) Sheet piles (2) D/S protection (3) U/S protection.