Full Text Transcript
Text below was recognized via OCR from scanned pages and may contain minor errors. Mathematical formulas and symbols may be approximate - please refer to the PDF for the exact equations.
Combined Geo-Scientist (Main)
Examination, 2024 SGSE-O-HDG
HYDROGEOLOGY
Time Allowed : Three Hours Maximum Marks : 200
QUESTION PAPER SPECIFIC INSTRUCTIONS
Please read each of the following instructions carefully
before attempting questions
There are NINE questions divided under FIVE Sections.
Candidate has to attempt FIVE questions in all.
The ONLY question in Section—A is compulsory.
Out of the remaining EIGHT questions, the candidate has to attempt FOUR, choosing
ONE from each of the other Sections B, 0, D and 2.
The number of marks carried by a question/part is indicated against it.
Symbols, abbreviations and notations have their usual standard meanings.
Neat sketches are to be drawn to illustrate answers, wherever required.
Wherever required, graphs/tables are to be drawn on the Question-cum-Answer (QCA)
Booklet itself.
Attempts of questions shall be counted in sequential order. Unless struck off, attempt of a
question shall be counted even if attempted partly.
Any page or portion of the page left blank in the Question-cum-Answer (QCA) Booklet
must be clearly struck off.
Answers must be written in ENGLISH only.
SGSE-O-HDG/65 1 [ 10.
1. Write short notes on the following in not more than 5 sentences each :
(a)
(b)
(0
(0)
(૭
(9)
(h)
धि
(c)
धि
(6)
SECTION—A
( Compulsory Section )
Secondary porosity
Specific retention
Storage coefficient
Intrinsic permeability
Cone of depression
Magnetometer
Well completion
Leachate
SECTION—B
Attempt any one question
Define aquifer and classify aquifers depending on the presence or absence of a
water table.
Discuss how the rock formations affect groundwater. Describe with neat
sketches.
How do thermal springs form? What are their implications?
Explain the derivation of Darcy’s law using the diagram of experimental setup.
Add a note on the equation and its application in groundwater flow studies.
Define hydraulic conductivity. Give an outline on the methods of determining
hydraulic conductivity in the laboratory and in the field. Explain any one of the
laboratory methods.
What is meant by aquifer transmissivity? Explain its relationship with the
other aquifer properties and thickness of saturated aquifer media with an
example.
SGSE-O-HDG/65 2
5x8=40
15
15
10
15
10
SECTION—C
Attempt any one question
4. (a) Explain the Bernoulli equation and its application in groundwater studies. 10
(b) Explain the terms advection, adsorption, diffusion and dispersion. Add a note
on their interrelationships. Discuss about their effects in groundwater
systems.
15
(c) In an aquifer system of 10000 sq. m flat area, the depth to the basement is
100 m below ground level (bgl). The specific yield (sy) is 0-01. The water
levels measured during pre- and post-monsoon are 40 m and 20 m bgl.
Determine (i) the volumes of water in aquifer storage during pre-monsoon and
post-monsoon and (ii) the change in groundwater storage due to monsoon. 15
5. (a) Describe the mechanisms of interactions between stream flow and
groundwater flow using appropriate illustrations.
10
(b) Explain the purpose of conducting pumping tests. Describe the stage-wise
procedures involved and the measurements recorded while conducting these
tests.
15
(c) What are the two major causes inducing land subsidence? Highlight their role
along with porous media properties.
SECTION—D
Attempt any one question
6. (a) How do you explore groundwater using electrical resistivity method?
15
15
(b) How do the surficial features identified on aerial photographs help in
evaluating groundwater conditions?
15
(c) What are the different recognised levels of groundwater management studies
generally carried out by local government agencies?
10
7. (a) Briefly describe seismic refraction method in exploration of groundwater with
neat sketches.
(b) Describe a test drill. Add a note on geologic log and its implications.
(c) Write short notes on the following :
(i) Radiation logging
(1) Water dowsing
SGSE-O-HDG/65 3
15
15
10
(2.1.0.
Attempt any one question
SECTION—E
How does freshwater occur in coastal regions? Explain the upcoming
phenomenon.
15
(૭) What are the uses of stable and radioactive isotopes? Discuss the radioactive
isotopes for the determination of the age of groundwater.
15
(c) A water sample contains 300 mg of CaSO, /litre. Calculate the hardness in
terms of CaCO 3 in mg/L.
methods of artificial recharge with sketches.
10
What is the difference between natural and artificial recharge? Explain various
15
(b) Explain how sodium is important in irrigation water classification. Add a note
on cation-exchange process.
(c) The following is the analytical data of a groundwater sample :
51 No. ডা t Units, mg/L Atomic weight
1 Calcium | 200 | 40-08
2 Magnesium 125 24:32
3 Sodium 1300 23:00
4 Potassium 15 39:10
5 Chloride 2300 35-56
| 6 | Sulphate 240 96-06
7 Nitrate "2ت2 62:01
| | Bicarbonate 330 61:01
(i) Check the accuracy of the analysis.
(ii) What is the electrical conductivity (EC) value?
SGSE-O-HDG/65
kkk
10
15
SB24—432
