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B
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SECOND SEMESTER M.TECH DEGREE EXAMINATION, APRIL 2018
(Civil Engineering)
M.Tech in Water Resources and Hydroinfromatics
07CE6404-Advanced Groundwater Hydrology
Time: 3 hours Max. Marks: 60
Answer all six questions. Part of each question is compulsory.
Answer either part or part of each question
Q.no. Module 1 Marks
1a Differentiate between aquifer and aquitard Unconfined aquifer
and confined aquifer
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Answer b or c
b Derive an expression for storage coefficient connecting the aquifer
properties porosity, density and bulk modulii. Also storage coefficient of
a confined aquifer of 25m thickness and porosity 20%. Bulk modulii of
aquifer and water are 1X108 and 2.1X109N/m2 respectively
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c The water budget calculation for a lake has been carried out for a year.
It is found that the average inflow into the lake is 15cumec and average
ourflow is 2 cumec. The average evaporation in that area is 1m per
year. Average surface area of the lake is 300 hectres. The storage in
the lake is increased by 10cm during the period. Estimate the amount
of groundwater recharge/flow into the lake during this one year
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Q.no. Module 2 Marks
2a Derive an equation for the steady radial flow towards a fully penetrating
well in an unconfined aquifer
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Answer b or c
b A confined aquifer with a transmissibility of 1000 lpm is situated
above an impervious base and overlain by a semi-confining layer with
a resistance of 2000 days against vertical leakage and above this layer
a homogeneous aquifer with constant water table is present. From the
leaky aquifer water is pumped at a rate of 800 lpm by a fully penetrating
well of 30 cm diameter. What is the drawdown in the well and at a
distance of 800m from the well, assuming the well yield is balanced by
the leakage
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c Derive Laplace Equation for groundwater flow 5
Q.no. Module 3 Marks
3a Derive the solution of unsteady groundwater flow equation in the polar
coordinates system.
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Answer b or c
b
A 30 cm well 75 m deep is proposed in an aquifer having a
transmissibility of 1.5x105 lpd/m and a coefficient of storage of 0.004.
The static water level is expected to be 20m below the ground level.
Assuming a pumping rate of 2000 lpm, what will be the drawdown in the
well after 1 year, 2 years?
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c Indicate how the Theis method of solution applied for estimating the
aquifer parameters?
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Q.no. Module 4 Marks
4a What is meant by well loss coefficient? Illustrate the method of
estimating the same by two methods
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Answer b or c
b Design a well for the flowing data. Discharge required =1500lpm. The
available thickness of the confined aquifer is 20m(from -40m to -60m
below ground level). The draw down in the well is limited to 13m. The
aquifer material has size of D10, D50 and D60 as 0.26mm,
0.43mm,0.65mm respectively. Make suitable assumptions.
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c
Five tube wells of 20 cm diameter are equally spaced along the
boundary of a circular well field of radius 200m. The wells fully
penetrate an artesian aquifer of thickness 20m, permeability 40 m/day
and storage coefficient 0.0002.Calculatethe draw downs in the well after
4 hours of the start of pumping if all the wells have the rate of
discharge 800 lpm. What is the draw down at the centre of well field?
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Q.no. Module 5 Marks
5a Describe various water spreading methods of recharge 5
Answer b or c
b What is meant by SAT? What are its components? Also indicate the
dynamics of the system by means of a block diagram.
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c A recharge basin 500X2500m is proposed for a new area with an
expected recharge rate of 99Mm3.The aquifer has a saturated thickness
of 22m and depth to the natural water table is 47m. T=2000m2/d. If the
maximum allowable rise of recharge mound is 38m, how far should be
the control area established from the centre line of the recharge basin.
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Q.no. Module 6 Marks
6a Illustrate how the depths of water table/layer are determined using
resistivity method, elucidating the basic principle behind this method.
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Answer b or c
b Differentiate between neutron, temperature and Gmma-Gamma logging 7
c What is the underlying principle behind Seismic refraction method.
Describe procedure for for determining the aquifer thicknesses. .
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