1(a) Describe the hydrologic
cycle. Explain briefly the man’s interference in various parts of this cycle.
(06 Marks)

(b) Explain the different methods
of determining the average rainfall over a catchment due to a storm. Discuss
the relative merits and demerits of the various methods. (06 Marks)

(c) What is meant by Probable
Maximum Precipitation (PMP) over a basin? Explain how PMP is estimated? (04
Marks)

(d) Analysis of data on maximum
one day rainfall depth at Chennai indicated that a depth of 280 mm had a return
period of 50 years. Determine the probability of a one day rainfall depth equal
to or greater than 280 mm at Chennai occurring (a) once in 20 successive years,
(b) two times in 15 successive years, and (c) at least once in 20 successive
years. (04 Marks)

2(a) Explain a procedure for
fitting Horton’s infiltration equation for experimental data from a given plot.
(06 Marks)

(b) List the various data needed
to use Penman’s equation for estimating the potential evapotranspiration from a
given area. (04 Marks)

(c) Discuss the importance of
evaporation control of reservoirs and possible methods of achieving the same.
(06 Marks)

(d) In a 140-min storm, the
following rates of rainfall were observed in successive 20-min intervals: 6.0,
6.0, 18.0, 13.0, 2.0, 2.0 and 12.0 mm/h. Assuming the φ-index value as 3.0 mm/h
and an initial loss of 0.8 mm, determine the total rainfall, net runoff and
W-index for the storm. (04 Marks)

3(a) Discuss the advantages and
disadvantages of the following relative to the flow measurement by using
current meters:

(i) Electromagnetic method (ii) Ultrasound method. (06 Marks)

(b) Explain the procedure for
obtaining the stage-discharge relationship of a stream by using the
stage-discharge data from a site with permanent control. (06 Marks)

(c) Describe briefly the moving
boat method of stream flow measurement. (04 Marks)

(d) It is proposed to adopt the
dilution method of stream gauging for a river whose hydraulic properties at
average flow are as follows:

Width = 45 m, Depth = 2 m,
Discharge = 85 m

^{3}/s, Chezy coefficient = 20 to 30. Determine the safe mixing length that has to be adopted for this stream. (04 Marks)
4(a) What is a hydrological
drought? What are its components and their possible effects? (06 Marks)

(b) Distinguish between yield and
surface water resources potential of a basin having substantial water resources
development for meeting irrigation, domestic and industrial needs within the
basin. (06 Marks)

(c) Describe briefly the SCS-CN
method of estimation yield of a catchment through use of daily rainfall record.
(04 Marks)

(d) A reservoir is located in a
region where the normal annual precipitation is 160 cm and the normal annual US class A pan
evaporation is 200 cm. The average area of reservoir water surface is 75 km

^{2}. If under conditions of 35% of the rainfall on the land occupied by the reservoir runoff into the stream, estimate the net annual increase or decrease in the stream flow as result of the reservoir. Assume evaporation pan coefficient = 0.70. (04 Marks)
5(a) Why is base flow separated
from the flood hydrograph in the process of developing a unit hydrograph? (04
Marks)

(b) Describe the S-curve method
of developing a 6-h UH by using 12-h UH of the catchment. (04 Marks)

(c) The 6-hour unit hydrograph of
a catchment is triangular in shape with a base width of 64 hours and a peak
ordinate of 30 m

^{3}/s. Calculate the equilibrium discharge of the S_{6}– curve of the basin. (06 Marks)
(d) The 6-hour unit hydrograph of
a basin is triangular in shape with a peak of 100 m

^{3}/s occurring at 24-h from the start. The base is 72-h.
(i) What is the area of the
catchment represented by this unit hydrograph?

(ii) Calculate the flood
hydrograph due to a storm of rainfall excess of 2.0 cm during the first 6 hours
and 4.0 cm during the second 6 hours interval. The base flow can be assumed to
be 25 m

^{3}/s constant throughout. (06 Marks)
6(a) Annual flood series having N
consecutive entries are available for a catchment. Describe a procedure to
verify whether the data follow Gumbel’s distribution. (06 Marks)

(b) Describe a numerical method
of hydrologic reservoir routing. (04 Marks)

(c) Describe the Muskingum method
of flood routing an inflow hydrograph through a channel reach. Assume the
values of coefficients K and x for the reach are known. (06 Marks)

(d) A rectangular parking lot is
150m wide and 300m long. The time of overland flow across the pavement to the
longitudinal gutter along the center is 20 minutes and the estimated total tome
of concentration to the downstream end of the gutter is 25 minutes. The
coefficient of runoff is 0.92. If a rainfall of intensity 6 cm/h falls on the
lot for 10 minutes and stops abruptly, determine the peak rate flow. (04 Marks)

7(a) Explain the behaviour of
water level in wells in confined aquifers due to changes in the atmospheric
pressure. (04 Marks)

(b) Describe a procedure by using
Jacob’s method to calculate the aquifer parameters of a confine aquifer by
using the well pumping test data. (06 Marks)

(c) What are Dupit’s assumptions?
(04 Marks)

(d) A 30-cm well completely
penetrates an artesian aquifer. The length of the strainer is 25m. Determine
the discharge from the well when the drawdown at the pumping well is 4.0m. The
coefficient of permeability of the aquifer is 345 m/day. Assume the radius of
the well as 350m. (06 Marks)

8(a) What is meant by Trap
Efficiency of a reservoir? What factors influence its value? (04 Marks)

(b) Explain the area-increment
method of determining the sedimental distribution in a reservoir. (06 Marks)

(c) Distinguish between USLE and
MUSLE? (06 Marks)

(d) A reservoir sediment is
estimated through use of Koezler equation to have average unit weight of 1100
kg/m

^{3}at the end of 35 years and 1120 kg/m^{3}at the end of 50 years. Estimate the average unit weight at the end of first year of deposit and at the end of 100 years. (04 Marks)
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