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What characteristic of an aquifer refers to the amount of water it can store?
High permeability allows water to flow quickly towards a well.
True
What happens to capillary water as sediment size increases?
Capillary water decreases.
Coarse-grained sediments are usually more ______ than fine-grained sediments.
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Which of the following terms describes the range of sediment sizes in a given area?
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Cohesion refers to water's attraction to other substances.
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What is a characteristic of poorly sorted sediment in relation to porosity?
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Match the following characteristics to their descriptions:
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What is the primary function of an aquifer?
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The water table is the surface below which the groundwater is fully saturated with water.
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Which type of sediment generally has lower permeability?
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What is the term for the process by which plants absorb water and release it into the atmosphere?
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More spherical grains typically result in lower porosity.
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What is the term for the refilling of groundwater from the surface?
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Water that remains in the soil after water is drained out is called ______.
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A _____ aquifer is one in which an impermeable layer exists above it, preventing water from seeping in.
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Match the following terms with their definitions:
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Which area below the surface is filled with water?
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Match the following terms with their definitions:
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Materials that allow water to pass through them are termed impermeable.
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Higher capillary water content in sediment occurs when:
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Well-drilled holes to obtain water are referred to as aquifers.
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What equation is used to define Specific Yield (Sy)?
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What kind of sediment typically has higher porosity?
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What occurs when the inputs in the water budget of a system are greater than the outputs?
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A deficit occurs when input is greater than output in a water budget.
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What is the term for when groundwater use exceeds recharge into an aquifer?
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When groundwater pumping reduces freshwater flow toward coastal areas, it can cause ______ intrusion.
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Which of the following is NOT a direct impact of groundwater overdraft?
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Rural landowners are more severely affected by groundwater overdraft due to limited financial resources.
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Match the following concepts to their definitions:
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List two indirect impacts of groundwater overdraft.
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Study Notes
The Water Cycle
- The water cycle is the continuous circulation of Earth's water supply.
Infiltration
- Infiltration is the process where surface water moves into the ground through cracks and pores in soil and rock.
Groundwater
- Groundwater is the water stored underground in the pores and crevices of soil and rock.
Aquifer
- An aquifer is a permeable layer of rock or sediment that stores and carries groundwater in enough quantities to supply wells.
Water Table
- The water table is the top of the groundwater, marking the boundary between the zone of saturation and the zone of aeration.
Zone of Saturation
- The zone of saturation is the area below the water table where the pores are filled with water.
Zone of Aeration
- The zone of aeration is the area above the water table where the pores are not filled with water.
Aquiclude
- An aquiclude is a solid, impermeable layer that lies above or below an aquifer, preventing groundwater movement.
Aquitard
- An aquitard is an impermeable bed that hinders or prevents groundwater movement.
Porosity
- Porosity is the percentage of a material's volume that consists of pore space.
Permeability
- Permeability refers to the rate at which water or other liquids can pass through the pore spaces of a rock.
Specific Retention
- Specific retention is the water that remains in the soil after water is drained out.
Specific Yield
- Specific yield (Sy) is the proportion of water occupying void spaces that drains under gravity. It is calculated by dividing the volume drained (Vd) by the total volume (Vt).
- Specific yield is always lower than porosity because some water is bound or adsorbed to the aquifer particles or fractures.
High Quality Aquifer Characteristics
- High porosity, allowing for more water storage.
- High permeability, facilitating rapid water flow towards wells.
- Low capillary water (specific retention), indicating less water retained in the sediment.
- High specific yield, enabling more water to be extracted from the aquifer.
Grain Size Effect on Aquifer Characteristics
- Porosity: Unaffected by sediment size.
- Permeability: Increases with increasing sediment size.
- Capillary Water: Decreases with increasing sediment size.
Grain Sorting Effect on Aquifer Characteristics
- Porosity: Typically lower for poorly sorted sediment (larger range of grain sizes).
- Permeability: Typically lower for poorly sorted sediment.
- Capillary Water: Typically higher for poorly sorted sediment.
Grain Packing (Overburden Stress) Effect on Aquifer Characteristics
- Porosity: Typically higher for loosely packed sediment.
- Permeability: Typically higher for loosely packed sediment.
- Capillary Water: Increases with more sediment in the same volume.
Grain Shape Effect on Aquifer Characteristics
- Porosity: Typically higher for more spherical grains.
- Permeability: Typically higher for more spherical grains.
- Capillary Water: Increases with more sediment in the same volume.
Unconfined Aquifer
- Unconfined aquifers allow water to directly seep into the aquifer from the ground surface above.
Confined Aquifer
- Confined aquifers have an impermeable layer preventing water from seeping directly into the aquifer from the surface above.
Well
- A well is a hole drilled into the earth to extract water, petroleum, natural gas, brine, or sulfur.
Recharge
- Recharge is the refilling of groundwater from the surface.
Recharge Area
- A recharge area is where water can seep into the ground and refill an aquifer due to the absence of a confining layer.
Discharge
- Discharge is the movement of groundwater from the subsurface to the surface.
Water Budget
- A water budget accounts for the inputs, outputs, and changes in the amount of water in a system (e.g., aquifer, lake) by breaking down the water cycle into components (input - output).
Surplus
- A surplus occurs when the inputs in a water budget are greater than the outputs.
Deficit
- A deficit occurs when the outputs in a water budget are greater than the inputs.
Usage
- Usage refers to plants drawing water from the soil when the need for moisture exceeds rainfall.
Groundwater Overdraft
- Groundwater overdraft occurs when groundwater use exceeds the rate of recharge, leading to a decline in groundwater level.
Direct Impacts of Groundwater Overdraft
- Reduced water supply due to aquifer depletion or contamination.
- Increased groundwater pumping costs and expenses for well replacement or deepening.
- Saltwater intrusion in coastal areas.
Indirect Impacts of Groundwater Overdraft
- Land subsidence and infrastructure damage.
- Harm to groundwater-dependent ecosystems.
- Economic losses due to a less reliable water supply.
Direct Impacts of Groundwater Overdraft: Reduced Water Supply and Increased Cost
- Rural landowners and small-scale farmers are disproportionately affected by overdraft. They often lack sufficient financial resources to dig new or deeper wells or diversify their water sources.
Direct Impacts of Groundwater Overdraft: Saltwater Intrusion
- Under normal conditions, the seaward flow of freshwater prevents saltwater from infiltrating coastal aquifers.
- Excessive groundwater pumping reduces the freshwater flow towards coastal areas, allowing saltwater to intrude into the freshwater zones of the aquifer.
Saltwater Intrusion Impacts
- It is a significant cause of groundwater quality degradation and a major challenge in managing groundwater resources in coastal regions.
- Increased salt concentration in groundwater limits its usability.
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Description
Test your understanding of the water cycle and groundwater concepts with this quiz. Explore terms like infiltration, aquifers, and the water table. It's perfect for students wanting to enhance their knowledge of hydrology.
