Ch 14

Aquifers
Porous, waterbearing layers of sand, gravel, and rock below the earth’s surface; reservoirs for ground water
Artesian well
the result of a pressorized aquifer intersecting the surface or being penetrated by a pipe or conduit, from which water gushes without being pumped, also called a spring.
Condensation
The aggregation of water molecules from vapor to liquid or solid when the saturation concentration is exceeded
Condensation nucli
Tiney particles that float in the air and facilitate the condinsation process
Consumption
The fraction of withdrawn water that is lost in transmission or that is evaporated, absorbed, chemically transformed, or otherwise made unavailable for other puroses as a result of human use.
Degradation
Deterioration in water quality due to contamination or pollution; makes water unsuitable for other desiable purposes.
Deslinization
Removal of salt from water by distillation, freezing, or ultrafiltration
Dew Point
The temperature at which condensation occurs for a given concentration of water vapor in the air
Discharge
The amount of water that passes a fixed point in a given amount of time, usually expressed as liters or cubic feet of water per second
Evaporation
The process in which a liquid is changed to a vapor
Groundwater
Water held in gravel deposits or porous rock below the earth’s surface; does not include water or crystallization held by chemical bonds in rocks or moisture in upper soil layers
Infiltration
The process of water percolation into the soil and pores and hollow of permeable rocks
Rain shadow
Dry area on the down wind side of a mountain
Recharge Zone
Area where water infiltrates into an aquifer
Relative humidity
At any given temperature, a comparison of the actual water content of the air with the amount of water that could be held at saturation
Renewable water supplies
Annual freshwater surface run off plus annual infiltration into underground freshwater aquifers that are accessible for human use.
Residence time
The length of time a component, such as an individual water molecule, spends in a particular compartment or location before it moves on through a particular process or cycle
Saltwater intrusion
Movement of saltwater into freshwater aquifers in costal areas where groundwater is withdrawn faster then it is replenished
Saturation Point
The maximum concentration of water vapor the air can hold at a given temperature
Sinkholes
A large surface crater caused by the collapse of an underground channel or cavern; often triggered by groundwater withdrawl.
Sublimation
The process by which water can move between solid and gaseous states without ever becoming liquid
Subsidence
A settling of the ground surface caused by the collapse of porous formations that result from withdrawl of large amounts of groundwater, oil, or other underground materials
Transpiration
The evaporation of water from plant surfaces, especially through stomates
Water stress
A situation when residents of a country don’t have enough accessible, high quality water to meet their everyday needs.
Water table
The top layer of the zone of saturatino; undulates according to the surface topography and surface structure
Watershed
The land surface and groundwater aquifers drained by a particular river system
Withdrawal
A description of the total amount of water taken from a lake, river, or aquifer
Zone of aeration
Upper soil layers that hold both air and water
Zone of saturation
Lower soil layers where all layers are fillled with water