Aqueduct Unit 3 Key Terms

aqueduct - an artificial channel for transporting water. Also called a canal. aquifer - an underground water resvoir. confined aquifer - a water-bearing porous layer of rock, sand, or gravel that is trapped between an upper and lower layer of less permeable substrate, such as clay. The water in a confined aquifer is under pressure because it is trapped between two impermeable layers. Also called an artesian aquifer. consumptive use - use of fresh water in which water is removed from a particular aquifer or surface water body and is not returned to it. Irrigation for agriculture is an example of consumptive use. dam - any obstruction placed in a river or stream to block the flow of water so that water can be stored in a reservoir. Dams are built to prevent floods, provide drinking water, facilitate irrigation, and generate electricity. desalination - the removal of salt from seawater to generate fresh water for human use. drainage basin - the area from which a single stream or river and its tributaries drains all of the water eutrophic - term describing a water body that has high-nutrient and low-oxygen conditions. flooding - the spillage of water over a river's bank due to heavy rain or snowmelt. floodplain - the region of land over which a river has historically wandered and periodically floods. fresh water - water that is relatively pure, holding very few dissolved salts. groundwater - water held in aquifers underground. hydraulic fracturing - a process to extract shale gas or tight oil, in which a drill is sent deep underground and angled horizontally into a shale formation; water, sand and chemicals are pumped in under great pressure, fracturing the rock; and gas migrates up through the drilling pipe as sand holds the fracture open. levee - a long raised mound of earth erected along a river bank to protect against floods by holding rising water in the main channel. non-consumptive use - use of fresh water in which the water from a particular aquifer or surface water body either is not removed or is removed only temporarily and then returned. the use of water to generate electricity in hydroelectric dams is an example. non-point source - a diffuse source of pollutants, often consisting of many small sources. oligotrophic - term describing a water body that has low-nutrient and high-oxygen conditions. point source - a specific spot- such as a factory- where large quantities of air pollutants or water pollutants are discharged. primary treatment - a stage of wastewater treatment in which contaminants are physically removed. Wastewater flows into tanks in which sewage solids, grit, and particulate matter settle to the bottom. Greases and oils float to the surface and can be skimmed off. recharge zone - an area where water infiltrates earth's surface and reaches an aquifer below. reservoir - an artifical water body behind a dam that stores water for human use. OR A location in which nutrients in biochemical cycle remain for a period of time before moving to another reservoir. can be living or nonliving entities. runoff - the water from precipitation that flows into streams, rivers, lakes, and ponds and in many cases eventually into the ocean. secondary treatment - a stage of wastewater treatment in which biological means are used to remove contaminants remaining after primary treatment. wastewater is stirred up in the presence of aerobic bacteria which degrade organic pollutants in the water. the wastewater then passes to another settling tank, where remaining solids drift to the bottom. sediment - the eroded remains of rocks septic system - a wastewater disposal method, common in rural areas, consisting of an underground tank and series of drainpipes. wastewater runs from the house to the tank, where solids precipitate out. the water proceeds downhill to a drain field of perforated pipes laid horizontally in gravel-filled trenches, where microbes decompose the remaining waste. shale gas - natural gas trapped deep underground in tiny bubbles dispersed throughout formations of shale, a type of sedimentary rock. gas is often extracted by hydraulic fracturing. shale oil - a liquid form of petroleum extracted from deposits of oil shale. sinkhole - a liquid form of petroleum extracted from deposits of oil shale. surface water - water located atop earth's suface. confined aquifer - a water-bearing porous layer of rock, sand or gravel that lies atop a less permeable substrate. The water in an unconfined aquifer is not under pressure because there is no impermeable upper layer to confine it. wastewater - any water that is used in households, businesses, industries, or public facilities and is drained or flushed down pipes, as well as the polluted runoff from streets and storm drains. water pullution - the release of matter or energy into waters that causes undesirable impacts on the health and well-being of humans or other organisms. water pollution can be physical, chemical or biological. water table - the upper limit of groundwater held in an aquifer. watershed - the entire are of land from which water drains into a given river. wetland - a system in which the soil is saturated with water and that generally features shallow standing water with ample vegetation. These biologically productive systems include freshwater marshes, swamps, bogs, and seasonal wetlands such as vernal pools. xeriscaping - landscaping using plants that are adapted to arid conditions.