Chapter 21: Water Supply, Use, and Management

aquifer
any underground body of sediment or rock that has sufficient size and sufficiently high porosity and permeability to provide an adequate supply of water from wells
channelization
an engineering technique that consists of straightening, deepening, widening, clearing, or lining existing stream channels; purpose is to control floods, improve drainage, control erosion, or improve navigation; very controversial practice that may have significant environmental impacts
cone of depression
a cone-shaped depression in the water table around a well caused by withdrawl by pumping of water at rates greater than the rates at which the water can be replenished by natural groundwater flow
consumptive use
a type of off-stream water use. This water is consumed by plants and animals or in industrial processes or evaporates during use. It is not returned to its source
desalination
removal of salts from seawater or brackish water so that the water can be used for purposes such as agriculture, industrial processes, or human consumption
drainage basin
the area that contributes surface water to a particular stream network
effluent
any material that flows outward from something; includes wastewater from hydroelectric plants and water discharged into streams from waste-disposal sites
effluent stream
type of stream where flow is maintained during the dry season by groundwater seepage into the channel
groundwater
water that sinks into the soil and is stored in slowly flowing and slowly renewed underground reservoirs called aquifers; underground water in the zone of saturation, below the water table
influent stream
type of stream that is everywhere above the groundwater table and flows in direct response to precipitation; water from the channel moves down to the water table, forming a recharge mound
in-stream use
type of water use that includes navigation, generation of hydroelectric power, fish and wildlife habitat, and recreation
off-stream use
type of water use where water is removed from its source for a particular use
overdraft
groundwater withdrawal when the amount pumped from wells exceeds the natural rate of replenishment
secondary treatment (of wastewater)
use of biological processes to degrade wastewater in a treatment facility
sinkhole
a depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof
sustainable water use
use of water resources that does not harm the environment and provides for the existence of high-quality water for future generations
vadose
a zone above the water table and below the land surface that is not saturated with water
water budget
inputs and outputs of water for a particular system (a drainage basin, region, continent, or the entire Earth)
water conservation
practices designed to reduce the amount of water we use
water table
the surface that divides the zone of aeration from the zone of saturation, the surface below which all the pore space in rocks is saturated with water