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.

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.

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.

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.

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.

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

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

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.