Chapter 11 - Groundwater & Water Resources Flashcards
What is porosity?
The proportion of void space in a material -holes or cracks, unfilled by solid material. It is a measure of how much fluid the material can hold.
What is permeability?
It is a measure of how readily fluids pass through a material.
What is known as the saturated zone or phreatic zone?
It is a volume of rock or soil that is water-saturated, in which water fills all the accessible pore space.
What is known as groundwater?
It is the water that is found in the saturated/phreatic zone. It is usually found, at most, a few km into the crust.
What is known as the unsaturated/vardose zone?
It is a zone of rock or soil in which the pore spaces are filled partly with water, partly with air.
What does soil moisture measure?
The amount of water in unsaturated soil.
What is known as the water table?
It is the top surface of the saturated zone.
What is known as recharge?
The processes of infiltration and migration or percolation by which groundwater is replaced.
When does groundwater discharge occur?
It occurs when groundwater flows into a stream, escapes at the surface in a spring, or exits the aquifer?
What is an aquitard?
It is a rock that may store a considerable quantity of water, but in which water flow is slowed.
What is an unconfined aquifer?
It is an aquifer that is directly overlain only by permeable rocks and soil.
What is known as a confined aquifer?
It is an aquifer which is bounded above and below by low-permeability rocks (aquitards).
What is an artesian system?
When a well is drilled into a confined aquifer, the water rises above its level because of the extra hydrostatic (fluid) pressure.
What does the potentiometric surface represent?
The height to which water’s pressure would raise if the water were unconfined.
How does hydraulic head influence water flows?
It affects the flow of water in its speed, groundwater flows from areas with higher hydraulic head to lower.
What is a cone of depression?
A circular lowering of the water table immediately around the well of an unconfined aquifer.
What is saltwater intrusion?
A problem that arises from the use of groundwater in coastal areas, which leads to the lens of freshwater to thin due to use.
What is a sinkhole?
It is a geological feature created when the ground collapses, usually due to a drop in the water table.
What is known as hard water?
Water which contains substantial amounts of dissolved calcium and magnesium.
