## Water Resources Engineering - Jun 17

### Civil Engineering (Semester 5)

Total marks: 80

Total time: 3 Hours
INSTRUCTIONS

(1) Question 1 is compulsory.

(2) Attempt any **three** from the remaining questions.

(3) Draw neat diagrams wherever necessary.

**1.a.**Define hydrology and list the applications of engineering hydrology.

**1.b.**What factors influence runoff and its volume? Briefly describe them.

**1.c.**What is a synthetic hydrograph and how can you derive it?

**1.d.**Compare shallow wells with deep wells

**1.e.**Enumerate the functions of irrigation water in raising crops

**1.f.**What are the various resources of irrigation water?

**1.g.**Define Balancing depth and derive a relation for its determination.

**1.h.**Give the criterion for selecting the following: (i) Bank width. (ii) Inspection roadway.

**1.i.**Explain the terms piping failure and exit gradient.

**1.j.**What assumptions were made by Bligh in his creep theory?

**2.a.**Discuss the advantage and disadvantages of recording type rain-gauges.

**2.b.**Derive a correlation equation between runoff and rainfall for a catchment with the following observation

**OR**

**3.a.**How can you check the adequacy of existing rain gauges?

**3.b.**A catchment area has seven rain gauges stations. The annual rainfall recorded by the gauges were 1200, 1420, 1180, 1085, 1650, 1020 and 1500 mm. For a 5 percent error in the estimation of the mean rainfall, calculate the minimum number of additional rain gauge stations required in the catchment

**4.a.**Explain the following methods used for developing a unit hydrograph of different durations:

(i) Method of superposition.

(ii) S- curve method.

**4.b.**During a recuperation test, the water level in an open well was depressed by pumping by 3.0 m and it recuperated to 2.0 m in 90 minutes.

(i) Determine the yield from a well of 5.0 m diameter under a depression head of 3.5 m.

(ii) Also find out the diameter of the well to yield 12 liters/second under a depression of 2.5 m.

**OR**

**5.a.**Define unit hydrograph. On what concept is it based and what are the assumptions made to derive it

**5.b.**Write short notes on the following:

(i) Pervious lined wells.

(ii) Unlined wells.

(iii) Impervious lined wells

**6.a.**Explain the following terms:

(i)Delta.

(ii) Base period.

(iii) Frequency of irrigation.

(iv) Paleo.

(v) Kor depth.

**OR**

**7.a.**Derive a formula for determining the time required to cover a given area of the strip

**7.b.**Determine: (i) The time required to irrigate an area of 0.7 hectares.

(ii) The maximum area that can be irrigated from a tube-well with a discharge of 0.035 m3/s. The infiltration capacity of the soil may be taken as 50 mm/hour and the average depth of flow of water as 150 mm.

**8.a.**Draw typical cross-section of an unlined canal:

(i) In cutting.

(ii) In filling.

(iii) In partial cutting and partial filling. Explain the functions of each component.

**8.b.**Design an irrigation channel in non-alluvium soil to carry a discharge of 7 m3 with a velocity of 0.7 m/s. Assume side slopes , bed slope 1 in 4444 and Manning's N = 0.0225.

**OR**

**9.a.**Write the short notes on the following:

(i) Spoil banks.

(ii) Land width.

(iii) Hydraulic gradient line in canals.

**9.b.**Give the anti-water logging measures for the following:

(i) Poor water management in the irrigated area.

(ii) Seepage from canals and water courses

**10.a.**State the essential features of Khosla's theory of seepage flow underneath weir. How does it differ from Bligh's theory?

**10.b.**What do you understand by the terms elementary profiles and practical profile.

**10.c.**Explain the Khosla's method of independent variables.

**OR**

**11.a.**Explain the Bligh's design criteria for safety against:

(i) Undermining.

(ii) Uplift pressures

**11.b.**Give the draw-backs of Bligh's creep theory.