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Questions and Answers
Why is it important to have a jug that holds more than 2 liters of water?
Why is it important to have a jug that holds more than 2 liters of water?
How is the measuring jug scaled to measure less than 2 mm of evaporation?
How is the measuring jug scaled to measure less than 2 mm of evaporation?
What is the purpose of the PVC pipe supporting the pointer during evaporation measurement?
What is the purpose of the PVC pipe supporting the pointer during evaporation measurement?
When rainfall exceeds the pan's capacity, what should be done to ensure accurate evaporation measurement?
When rainfall exceeds the pan's capacity, what should be done to ensure accurate evaporation measurement?
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In the text, how is evaporation calculated when rainfall occurs before evaporation measurement?
In the text, how is evaporation calculated when rainfall occurs before evaporation measurement?
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If 5 mm of rainfall occurs and 2 mm of water are added to the pan with the measuring jug, what is the evaporation measurement?
If 5 mm of rainfall occurs and 2 mm of water are added to the pan with the measuring jug, what is the evaporation measurement?
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What is the primary purpose of measuring both rainfall and evaporation?
What is the primary purpose of measuring both rainfall and evaporation?
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What is the recommended time for performing evaporation measurements?
What is the recommended time for performing evaporation measurements?
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Which condition is essential for the appearance of subsurface flows?
Which condition is essential for the appearance of subsurface flows?
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How does the drainage capacity of subsurface flows compare to superficial and groundwater flows?
How does the drainage capacity of subsurface flows compare to superficial and groundwater flows?
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What type of flow occurs when infiltrated effective rainfall circulates in the superior soil layer?
What type of flow occurs when infiltrated effective rainfall circulates in the superior soil layer?
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In which regions is subsurface flow dominant?
In which regions is subsurface flow dominant?
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What historical term was used to refer to subsurface flow?
What historical term was used to refer to subsurface flow?
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What does the term $H_n$ represent in the energy balance equation?
What does the term $H_n$ represent in the energy balance equation?
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Which of the following terms can be neglected when time periods are short?
Which of the following terms can be neglected when time periods are short?
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How is the sensible heat term $H_a$ estimated?
How is the sensible heat term $H_a$ estimated?
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In the context of evaporation estimation, which factor contributes to the latent heat of evaporation?
In the context of evaporation estimation, which factor contributes to the latent heat of evaporation?
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What is the purpose of the Mass-Transfer Method?
What is the purpose of the Mass-Transfer Method?
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Which variable is NOT included in the Bowen's ratio equation?
Which variable is NOT included in the Bowen's ratio equation?
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What is the significance of the errors being around 5% in evaporation estimation?
What is the significance of the errors being around 5% in evaporation estimation?
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What does the latent heat of evaporation formula depend on?
What does the latent heat of evaporation formula depend on?
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What is the recommended percentage open area for a well screen to prevent incrustation and corrosion?
What is the recommended percentage open area for a well screen to prevent incrustation and corrosion?
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Which of the following is NOT one of the assumptions of Dupuit's equations?
Which of the following is NOT one of the assumptions of Dupuit's equations?
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Which condition can lead to unsteady flow in a well?
Which condition can lead to unsteady flow in a well?
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What does the Theis equation assume about the water being pumped from a well?
What does the Theis equation assume about the water being pumped from a well?
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What does Dupuit's equation assume about well efficiency?
What does Dupuit's equation assume about well efficiency?
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Which of the following characteristics of flow around a well is assumed in Dupuit's derivation?
Which of the following characteristics of flow around a well is assumed in Dupuit's derivation?
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Under what circumstance can drawdowns in a well increase with prolonged pumping?
Under what circumstance can drawdowns in a well increase with prolonged pumping?
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Which investigators contributed to the study of hydraulics of wells in unsteady flow conditions?
Which investigators contributed to the study of hydraulics of wells in unsteady flow conditions?
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Which geological formations serve as effective aquifers?
Which geological formations serve as effective aquifers?
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What is an aquiclude?
What is an aquiclude?
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What characterizes an aquifuge?
What characterizes an aquifuge?
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How is specific yield defined?
How is specific yield defined?
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Which of the following best describes a confined aquifer?
Which of the following best describes a confined aquifer?
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What is the formula relating porosity, specific yield, and specific retention?
What is the formula relating porosity, specific yield, and specific retention?
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What does specific retention refer to?
What does specific retention refer to?
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What is a key factor influencing specific yield in aquifers?
What is a key factor influencing specific yield in aquifers?
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Which of the following is NOT a factor that affects pan evaporation?
Which of the following is NOT a factor that affects pan evaporation?
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What is the main advantage of large weighable lysimeters over smaller ones?
What is the main advantage of large weighable lysimeters over smaller ones?
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Why is it important to use the same type of pan in measuring evaporation?
Why is it important to use the same type of pan in measuring evaporation?
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Which of these is NOT a technique used in hydraulic weighing systems for lysimeters?
Which of these is NOT a technique used in hydraulic weighing systems for lysimeters?
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What is the primary use of micro lysimeters?
What is the primary use of micro lysimeters?
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According to the passage, which of the following techniques would be most appropriate for accurate measurement of evapotranspiration in a research center?
According to the passage, which of the following techniques would be most appropriate for accurate measurement of evapotranspiration in a research center?
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How can pan evaporation measurements be used in agriculture?
How can pan evaporation measurements be used in agriculture?
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What is the main difference between weighable lysimeters used for short-term and long-term measurements?
What is the main difference between weighable lysimeters used for short-term and long-term measurements?
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Study Notes
Preface
- This hydrology module aims to detail the theory and application of hydrology.
- The course covers the hydrologic cycle and related processes such as precipitation, evaporation, infiltration, overland flow, groundwater flow, and surface runoff generation.
- The module development was influenced by COVID-19 pandemic comments and peer reviewer feedback, alongside faculty input intended to ensure quality module distribution.
Unit 5: Evaporation
- Definitions: Evaporation is the process of a liquid changing to a gas below boiling point due to heat transfer.
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Factors Affecting Evaporation:
- Vapor Pressure: The rate is proportional to the difference between saturation vapor pressure (at the temperature) and actual vapor pressure in the air.
- Temperature: A higher water temperature results in a faster evaporation rate.
- Wind: Increased wind removes evaporated water vapor, increasing evaporation rate up to a critical wind speed.
- Atmospheric Pressure: Lower pressure generally leads to faster evaporation.
- Soluble Salts: The presence of salts in water lowers the evaporation rate.
- Heat Storage: Deep water bodies store more heat, affecting seasonal evaporation patterns compared to shallow bodies.
Unit 5: Evaporation (Continued)
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Measurement:
- Lysimeters: Measure evapotranspiration by recording precipitation and water loss in soil-filled containers, used for long-term measurements of plants, often crops or trees.
- Evaporation Pans: Standardised pans such as the Class A pan used for measuring evaporation from free water surfaces.
Unit 6: Basic Subsurface Flow
- Introduction: Subsurface flow is the horizontal movement of infiltrated water. It's affected by the presence of an impermeable layer.
- Darcy's Law: The velocity of groundwater flow is proportional to the hydraulic gradient. The equation is V = ki, where V is velocity, k is hydraulic conductivity and i is the hydraulic gradient.
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Aquifers: Formations that transmit water efficiently.
- Unconfined Aquifers: Water table aquifers, where the water level is at the top of the saturated zone.
- Confined Aquifers: Artesian aquifers, where pressure forces water to rise above the water table.
- Transmissibility: The flow capacity of an aquifer per unit width under a unit hydraulic gradient, and is equal to the product of permeability times the saturated thickness of the aquifer.
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Water Conditions:
- Steady radial flow into a well.
- Steady state conditions; pumping has been continuous long enough to reach equilibrium.
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Description
This quiz focuses on Unit 5 of the Hydrology module, emphasizing the important processes and factors affecting evaporation. Explore key concepts such as vapor pressure, temperature effects, and the role of wind in evaporation rates. Perfect for students looking to deepen their understanding of hydrological processes.