# Water Resources and Irrigation Engineering April 2011

CE 606 A/B WATER RESOURCES AND IRRIGATION ENGINEERING

(2006 Scheme)

PART-A

I. (a) Distinguish between hydrograph and hyetograph.

(b) With neat sketches explain any one automatic rain gauges.

(c) Write notes on :

(i) storage coefficient

(ii) coefficient of transmissibility

(d) Define duty and delta

(e) Describe the function of siphon spillway with neat sketch.

(f) What are the function of canal head regulator?

(g) Explain the purpose of Galleries in dam.

(h) Discuss in brief the causes of failure of earth dams.

PART-B

II.  (a) Explain different types of precipitation.

(b) There are four rain gauge stations existing in the catchment. The average annual rainfall values at these stations are 800, 620, 400 and 540 mm respectively. Determine the optimum number of rain gauges in the catchment, if it is desired to limit the error in the mean value of rainfall in the catchment to 10%. How many more gauges will then be required to be installed?

OR

III. (a) What is run – off? What are the factors effecting run – off?

(b) A 12 – hour storm rainfall with the following depth in cm occurred over a basin : 2.0, 2.5, 7.6, 3.8, 10.6, 5.0, 7.0, 10.0, 6.4, 3.8, 1.4 and 1.4. The surface run – off resulting from above storm is equivalent to 25.5 cm of depth over basin. Determine average infiltration index for basin.

IV. (a) Derive an expression to find the discharge from an unconfined aquifer with neat sketches.

(b) A tube well of 30 cm diameter penetrates fully in an arterian aquifer. The strainer length is 15 m. Calculate the yield from the well under a drawdown of 3 m. The aquifer consist of sand of effective size 0.2 mm having permeability equal to 50 m/day. Assume radius of drawdown equal to 150 m.

OR

V. (a) What are the factors effecting the selection of site for reservoir?

(b) Write notes on reservoir sedimentation.

VI. Explain with the help of a diagram the various component parts, along with their functions of a diversion head work.

OR

VII. The cross – section of weir is shown in figure. Calculate :

(i)  Uplift pressure at point A and E

(ii) Thickness of concrete apron at point B

VIII. (a) Distinguish clearly between a low gravity dam and high gravity dam. Derive the expression used for such distinction.

(b) Design the practical profile of a gravity dam of stone masonry given the following data:

R.L. of base of dam                 = 1250 m

R.L. of base of H.F.L.               = 1280 m

Specific gravity of masonry    = 2.4

Safe compressive stress for masonry of dam = 1201 / m2

OR

IX. (a) Explain the cause of failure of earth dams.

(b) Draw a neat figure and show the principal parts of a rock fill dam.