Describes a confined aquifer containing groundwater that will flow upwards out of a well without the need for pumping.
tiny bits of particulate matter that serve as surfaces on which water vapor condenses
fraction of withdrawn water that is lost in transmission, evaporation, absorption, chemical transformation, or otherwise made unavailable for other purposes as a result of human use.
involves removing dissolved salts from ocean water or from brackish (slightly salty) water in aquifers or lakes for domestic use.
the temperature at which the water vapor in the air becomes saturated and condensation begins
Water found in the spaces between soil particles and cracks in rocks underground (located in the saturation zone). A natural resource that is used for drinking, recreation, industry, and growing crops.
the low-rainfall region that exists on the leeward (downwind) side of a mountain range. Is the result of the mountain range's causing precipitation on the windward side.
the percentage of water vapor in the air compared to the maximum amount the air could hold
renewable water supplies
annual freshwater surface runoff plus annual infiltration into underground freshwater aquifers that are accessible for human use
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
Movement of salt water into freshwater aquifers in coastal and inland areas as groundwater is withdrawn faster than it is recharged by precipitation.
a large surface crater caused by the collapse of an underground channel or cavern; often triggered by groundwater withdrawal
the phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid first
A depression of the land surface as a result of groundwater being pumped. Cracks and fissures can appear in the land. Is virtually an irreversible process.
the land of area from which surface runoff drains into a stream, channel, lake, reservoir, or other body of water; also called a drainage basin
a situation when residents of a country don't have enough accessible, high-quality water to meet their everyday needs
Upper surface of the zone of saturation, in which all available pores in the soil and rock in the earth's crust are filled with water.
zone of aeration
A subsurface zone above the water table where the rock or soil may be moist but not saturated, with air occupying some or all of the pore space; also called the unsaturated zone.
zone of saturation
lower region of groundwater where all the pore spaces in a rock or sediment are filled with water
contaminants carried by air currents and precipitated into watersheds or directly onto surface waters
biochemical oxygen demand
the amount of oxygen required for aeroic organisms to decomose organic material in wastewater over a five- to twenty-day period; the usual measure is five days
Bacteria that live in the intestines (including the colon) of humans and other animals, used as a measure of the presence of feces in water or soil.
Overnourishment of aquatic ecosystems with plant nutrients (mostly nitrates and phosphates) because of human activities such as agriculture, urbanization, and discharges from industrial plants and sewage treatment plants.
free oxygen (O2) released into the water by photosynthesis and by air-water interactions; it is essential for the respiration of aquatic animals
a condition in a lake or other body of water that is characterized by lush phytoplanktonic growth followed by high amounts of decay in the bottom resulting in depletion of oxygen in the water column.
large or dispersed land areas such as crop fields, streets, and lawns that discharge pollutants into the environment over a large area
Decline in oxygen downstream from a pollution source that introduces materials with high biological oxygen demands.
specific locations of highly concentrated pollution discharge, such as factories, power plants, sewage treatment plants, underground coal mines, and oil wells
first step of sewage treatment; eliminates most particulate material from raw sewage using grates, screens, and gravity (settling).
a bloom of dinoflagellates that causes reddish discoloration of coastal ocean waters. Certain dinoflagellates of the genus Gonyamlax produce toxins that kill fish and contaminate shellfish.
second step of sewage treatment; bacteria breakdown organic waste, aeration accelerates the process.
the third level of sewage treatment; chemicals, filters, and radiation are used to remove all particles and all harmful chemicals and bacteria.