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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 Hydro-informatics
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 Draw a vertical profile of soil strata indicating the zone of saturation,
aeration, water table, capillary fringe in case of an unconfined aquifer.
Does these zones exist for confined aquifer?.
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Answer b or c
b Define Darcy's law. What are the assumption and limitation in the
application of this law. How do you test the whether Darcy;s law is
applicable
5
c Derive an equation for land subsidence in terms of the bulk modulii of
water, aquifer thickness, storage coefficient and porosity. Estimate the
land subsidence if piezometric head drops by 50m in an artiesian
aquifer of thickness 40m, having a porosity of 25% and storage
coefficient of 0.0003. Bulk modulii of aquifer and water are 1X108 and
2.1X109N/m2 respectively.
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Q.no. Module 2 Marks
2a List all (at least assumptions and its implications in the derivation of
steady radial flow towards a well in a unconfined aquifer.
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Answer b or c
b An aquifer averages 60m in thickness and is 200ha in area. Determine
the volume in cubic m of water available if the aquifer is unconfined
and is completely drained the aquifer is confined and the piezometric
head is lowered from 30m to 10m above the aquifer the aquifer is
confined and the head is lowered 55m which brings the water table 25m
below the confining layer. Credit will be given for assuming appropriate
aquifer parameters
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c Draw an image well system for a pumping well, located near 45 degree
corner with one of the boundaries as recharging and the other as
impermeable both the boundaries are recharging both
boundaries are impermeable
.
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Q.no. Module 3 Marks
3a Is it possible to apply the solution for unsteady radial flow towards a well in
confined aquifer to that in unconfined aquifer? If so, under what conditions
it is applicable and states the implication of these assumptions?
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Answer b or c
b The drawdown in an observation well 15 m away from the pumping well are
3 and 4 m after 10 and 100 min of starting pumping. What are the
corresponding drawdowns in an observation well 150 m away from the
pumping well? What will be corresponding drawdown in a well which is
located at 75m.
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c Illustrate how the aquifer parameters are estimated from the observation 5
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data from bore well in a leaky aquifer?
Q.no. Module 4 Marks
4a Differentiate between open well and tube well. Also discuss the
advantages and disadvantages of the both these types
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Answer b or c
b The coefficient of transmissibility and storage of a non-leaky artesian
aquifer are 3X105 lpd/m and 2X10-4, respectively. The aquifer is bounded
on one side by a barrier boundary. A fully penetrating production well has
been discharging at a constant rate of 1000lpm. The drawdown in an
observation well 40m from the pumping well due to the effects of the barrier
boundary for a pumping period of 2hr is 2.5m. What should be the
approximate distance of the pumping well from the barrier boundary?
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c A 5m diameter open well has a normal water level of 7m below ground
level (b.g.l). By pumping the water level in well has been reduced to 16m
b.g.l. Water level was recuperated to 9m b.g.l in 1.5hours. Determine the
specific yield of the well. Comment on the type of aquifer material. Assume
the allowable draw down of the well as 5m. Design a well to take out
discharge of 2000lpm.
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Q.no. Module 5 Marks
5a Derive an expression for the depth of sea water interface below an
oceanic circular island when there is an infiltration of w and also when
there is no infiltration
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Answer b or c
b Deduce the basic governing equation for conservative contaminant
transport modelling
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c The interface of salt water and freshwater is located at 32m below ground
level at 105m landward. The depth of homogeneous aquifer is 50m below
m.s.l. and has a permeability of 100m/day. How much is the fresh water
flow into the sea. Estimate the gap through which the fresh water escapes
into the sea.
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Q.no. Module 6 Marks
6a How do we use meteorological data in the assessing the groundwater
potential?
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Answer b or c
b How shall the drilling method be superior to the other methods of
geophysical exploration? When shall be this method adopted? Advantages
and disadvantages of the same
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c In seismic refraction method, 5 geophone were placed at 40, 60, 80, 100,
and 140 and the time of first arrival of wave in milli seconds are 80, 113,
152, 164, and 182 respectively. Determine the velocity of shock wave in
first and second layers and also determine the thickness of the first layer.
Comment on the type of layers.
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