APES Chapter 13: Water Resources

freshwater

Water that contains very low levels of dissolved salts

groundwater

Water that fills the cracks and spaces in underground soil and rock layers

zone of saturation

An area beneath the Earth's surface which extends downward until all of the open spaces in sediment and rock are completely filled with water

water table

The upper level of the saturated zone of groundwater

aquifer

An underground water reservoir.

natural recharge

Natural replenishment of an aquifer by precipitation, which percolates downward through soil and rock

lateral recharge

Water that replenishes an aquifer from the side from sources such as streams

nonrenewable aquifer

An aquifer that receives very little, if any, recharge; deep underground and must be mined to yield water

surface water

The freshwater that flows across the Earth's land surface into rivers, streams, lakes, etc.

surface runoff

Precipitation that does not return to the atmosphere by evaporation or infiltrate into the ground

watershed

The area of land that is drained by a water system; drainage basin

reliable surface runoff

Surface runoff that generally can be counted on as a stable source of water from year to year

water footprint

An estimate (for an individual or a nation) of the amount of water required to sustain the consumption of goods and services

virtual water

Water that is not directly consumed but is used to produce food and other products

water hotspots

Areas with high levels of competition for water

land subsidence

A gradual (or sudden) settling of land when groundwater that previously filled cavities in the land is pumped out

sinkhole

A depression produced in a region where soluble rock has been removed by groundwater

dam

A structure built across a river to control its flow

reservoir

A large artificial lake used as a source of water supply

California State Water Project

The world's largest publicly built and operated water and power development and conveyance system; original purpose was to provide water for arid Southern California which lacks adequate local water resources to provide for the growth the region has experienced

desalination

Purification of salt water or brackish (slightly salty) water by removal of dissolved salts

reverse osmosis

A desalinization process that involves forcing salt-water through a membrane permeable to water but not to salt

distillation

A process of desalinization in which water is evaporated and then recondensed

lifeline rates

The process of giving each household a set amount of water at a low price to meet basic needs

user-pays approach

A means of discouraging water waste (and other resource waste) by charging a fee to withdraw water for consumptive us

flood irrigation

Watering crops by pumping water to fields and letting it flow via gravity through unlined ditches to surround crops; very wasteful

center-pivot, low pressure sprinkler

80% efficient method of delivering water to crops using pumps and a mobile central boom with sprinklers to mist water directly on crops

drip irrigation

A highly-effective form of irrigation that uses pipe or tubing perforated with very small holes to deliver water one drop at a time directly to the soil around each plant

tensiometer

Instrument used to measure soil moisture

gray water

Domestic wastewater composed of wash water from household sinks, tubs, and washers

floodplain

A low plain adjacent to a river that is formed chiefly of river sediment and is subject to flooding

channelization

An engineering technique to straighten, widen, deepen, or otherwise modify a natural stream channel

Ogallala

The largest known aquifer in North America

percolation

The process by which water moves downward in the soil, toward the water table

infiltration

Flow of water from the land surface into the subsurface.

transpiration

Evaporation of water from the leaves of a plant

hydrologic cycle

The movement of water through the biosphere

overdraft

Groundwater withdrawal when the amount pumped from wells exceeds natural rate of replenishment

Aral Sea

An inland saltwater sea in Katzakstan and Uzbekistan

polyculture

Growing several crops on the same plot simultaneously

Bangladesh

South Asian country prone to flooding due to being situated on the Ganges Delta and the many distributaries flowing into the Bay of Bengal

xeriscaping

A method of landscaping that uses plants that are well adapted to the local area and are drought resistant

China South-North Water Transfer Project

Uses canals, reservoirs, dams to transfer water from southern regions to drier northern regions, 10 times larger than the California Water Project

hydroelectic power

electricity produced by moving water