National Drought Mitigation Center


aquifer: an area that contains large amounts of water under the surface of the earth.

climate: day-to-day weather over a longer period of time. Climatology is the study of climate.

climatologist: a scientist who studies climate.

climograph: a graph that shows monthly average temperature and precipitation for some location.

dam: a structure built across a river to hold back water for a variety of reasons, including protecting areas from floods, storing water, and generating power.

desalination: the process of removing salts and other minerals from seawater so that it can be used for drinking water.

drought: less rainfall than is expected over an extended period of time, usually several months or longer. Or, more formally, it is a deficiency of rainfall over a period of time, resulting in a water shortage for some activity, group, or environmental sector.

drought index: a numerical scale that scientists use to describe the severity of a drought. Scientists take many kinds of data (like streamflow, rainfall, temperature, and snowpack) and "blend" it into a single number, called a drought index value, to make it easier to understand the drought conditions of a particular area.

Dust Bowl: an area of the U.S. Plains that included parts of Kansas, Colorado, Oklahoma, Texas, and New Mexico. The term was coined in the 1930s, when dry weather and high winds caused many dust storms throughout the United States, but particularly in this area.

elevation: an area's height above sea level.

El Niño: a weather phenomenon that occurs in the eastern and central equatorial Pacific Ocean. During an El Niño, the affected area's winds weaken and sea temperatures become warmer.

erosion: a process that wears the earth's surface away, causing soil to move from one place to another. It's a natural process, but human activities can make it worse.

glacier: a mass of ice that slowly moves over land.

groundwater: water that is found underground in spaces in soil, sand, or rocks.

hydroelectricity: electricity created by channeling water through turbines in power stations located below dams.

ice cap: a permanent covering of ice and snow. Mountaintops and the North and South poles have ice caps.

indicators: something observed or calculated that shows what conditions are.

irrigation: an agricultural practice that involves providing water to crops through pipes, ditches, or streams.

jet stream: strong wind currents at high altitudes in the earth's atmosphere. They are thousands of miles long and hundreds of miles wide, and they move weather patterns around the earth.

La Niña: a weather phenomenon that involves unusually cold ocean temperatures in the equatorial Pacific Ocean. La Niña events don't occur as often as El Niño events.

latitude: on a map, the imaginary parallel east-west lines. They are used to tell us how far north or south of the equator we are. They are measured in degrees (but not temperature degrees!).

limited renewable resource: a renewable resource (see definition below) that takes a fairly long time to renew itself, like a forest, in comparison to a resource that can be rapidly renewed, like an agricultural crop.

limited resource: a natural resource that is limited in supply and cannot be replaced (or replaced quickly enough) if it is used up.

mitigation: actions that we can take before, or at the beginning of, drought to help reduce the impacts of drought.

natural hazards: physical events, like droughts and floods, that are harmful to people and/or destructive to property.

percolation: the slow movement of water (or another liquid) through something, like soil or rocks.

pollution: the process of making something (like our air, soil, or water) unclean.

renewable resource: a natural resource (like wood or solar energy) that can be renewed naturally over time.

reservoirs: water that's collected and stored in natural or manmade lakes.

runoff: water from rain, melting snow, or irrigation that flows over the land and into streams or other surface waters instead of being absorbed into the ground.

submarginal farmland: lands with nutrient-poor soils and/or soils that have been damaged by poor cultivation practices.

teleconnection: a relationship between two distant weather events. The weather phenomenon El Niño, for example, has been linked to a wide variety of events, including wildfires in the Australian Outback, flooding in the Peruvian Andes, and above-normal rainfall in the Greater Horn of Africa.

water banking: a water management strategy that temporarily transfers water from those who are willing to lease it to those who are willing to pay to use it.

water recycling: reusing treated wastewater for purposes like agricultural and landscape irrigation. It's also referred to as water reclamation or water reuse.

weather: the condition of the earth's atmosphere over a brief period of time, like a day or a week.

xeriscaping: a type of landscaping around homes and businesses that uses a limited amount of water.