JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B. Tech III Year GROUND WATER DEVELOPMENT AND MANAGEMENT Previous Question Paper (July - 2023 - R16)
Answer any five questions.
Question paper consists of Part A, Part B.
Part A is compulsory, which carries 25 marks. Answer all questions.
Part B: Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Define specific yield and specific retention.
Answer
Specific yield is the volume of water that an aquifer releases from storage per unit surface area of aquifer per unit decline in the water table. Specific retention is the volume of water that a rock or soil will retain against the force of gravity per unit volume of the material.
Distinguish between Darcy velocity and actual velocity.
Answer
Darcy velocity (or discharge velocity) is the total discharge per unit cross-sectional area of the porous medium. Actual velocity (or seepage velocity) is the actual speed at which water particles move through the interconnected pore spaces, calculated as Darcy velocity divided by the effective porosity.
What is steady and unsteady radial flow to wells?
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What do you mean by ground water potential?
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Write the 3D equation for unsteady ground water flow.
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Write the equation for steady radial flow for unconfined aquifer.
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What is ground water table?
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List surface and sub-surface investigation of ground water.
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What is conjunctive use of Ground Water?
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Why does sea water intrusion occur?
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Part B
Discuss in detail the occurrence and movement of ground water.
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With a neat sketch, explain about confined and unconfined aquifers.
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Water table of an aquifer drops by 115 cm over an area of 985 km2. The porosity and specific retention of the aquifer material are 30% and 6% respectively. Find the amount of water drained out (expressed in km3) from the area?
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Classify the different types of wells and state the advantages and disadvantages of the open wells.
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The thickness of an unconfined aquifer is 2.4 m. A well penetrated in this aquifer is pumped at a uniform rate of 10 lit./sec. till the water level in the well becomes constant. Two observation wells drilled at a radial distance of 25 and 100 meter respectively from the axis of the well show depression of 3.5 m and 1.4 m respectively. Find out the value of coefficient of permeability.
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A field sample of an unconfined aquifer is packed in a test cylinder. The length and the diameter of the cylinder of the cylinder are 50 cm and 6 cm, respectively. The field sample is tested for a period of 3 minute under a constant head difference of 16.3 cm. As a result 45.2 cm3 of water is collected at the outlet. Determine the hydraulic conductivity of the aquifer sample.
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Derive an expression for coefficient of transmissibility ‘T’ of an unconfined aquifer.
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Explain the limitations of Theim’s equations.
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For an unconfined aquifer consisting of fine sand, the following hydraulic characteristics are estimated: What is the minimum pumping time that yield is no longer delayed and Theis equation is applicable.
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A well of 0.5 m in diameter penetrates 33 m below the static water table. After a long period of pumping at a rate of 80 m3/hour, the draw down in wells is 18 m and 45 m from the pumped well were found to be 1.8 m and 1.1 m respectively. What is the transmissivity of the aquifer and determine the radius of influence of the pumping well.
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Explain Recuperation test.
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Why it is important to study land forms in sub surface investigation?
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What is remote sensing and how it is used in sub surface ground water investigation?
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Define artificial recharge and explain the favorable conditions for artificial recharge.
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Explain the basin type of ground water recharge with neat diagram.
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What are jetted wells and driven wells?
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Explain the methods for drilling deep wells.
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Explain the Ghyben- Herzberg relation for sea water intrusion.
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Explain ground water basin management.
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