Glossary of terms provided by the National Drought Mitigation Center

adaptation: The Intergovernmental Panel on Climate Change uses adaptation to refer to measures taken ahead of time to reduce vulnerability to climate change. Taking measures ahead of time to reduce vulnerability is what the NDMC means by mitigation. See also mitigation.

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 extent 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. Drought indices are one type of drought indicator.

Drought Indices: Assimilate data on rainfall, snowpack, streamflow, and other water supply measurements into a comprehensible picture of drought development and severity (NDMC website, “What Is Drought: Drought Indices,” Michael Hayes). Some examples of common drought indices are: Palmer Drought Severity Index, Crop Moisture Index, Surface Water Supply Index, and the Standardized Precipitation Index.

drought indicator: a way to look at one or more variables, such as precipitation, to describe available water in soil or hydrologic systems. It may be a record of a single measurement, such as rainfall at a particular rain gauge. It may also be a complex index. Drought indices (indexes) are a subset of drought indicators.

Drought Management Planning: Includes drought mitigation and drought response planning. The main objective of drought management planning is to preserve essential public services and minimize the adverse effects of a water supply emergency on public health and safety, economic activity, environmental resources, and individual lifestyles.

Drought Mitigation: Refers to actions taken in advance of a drought that reduce potential drought-related impacts when the event occurs. This includes measures taken in advance of a disaster that are aimed at decreasing or eliminating drought impacts on society and the environment.

Drought Stages: Describe the severity levels of drought and are generally differentiated by pre-defined trigger points or thresholds.

Drought Types:
Meteorological drought – a period of below-average precipitation.
Agricultural drought – a period of inadequate water supply to meet the needs of the state’s crops and other agricultural operations such as livestock.
Hydrological drought – deficiencies in surface and subsurface water supplies. Generally measured as streamflow, snowpack, and as lake, reservoir, and groundwater levels.
Socioeconomic drought – occurs when drought impacts health, well-being, and quality of life, or when a drought starts to have an adverse economic impact on a region.

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.

impact: Measured or observed affect of drought that could include social, economic, and environmental sectors.

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. Mitigation includes actions as diverse as drought planning, implementing land use practices that increase the organic content and water-holding capacity of soil, and designing agricultural policy that doesn’t encourage short-term economic gains at the expense of long-term productive capacity. The Intergovernmental Panel on Climate Change uses mitigation to mean reducing emissions of greenhouse gasses.

operational definition of drought: how agencies, communities, or individuals will recognize a drought in its early stages. Do they have their own rain gauge, river flow meter, or water level meter? Do they rely on state or national climatological data? Do they have a unique way to measure soil moisture, such as the appearance of certain plants or other environmental features?

Reservoirs: water that's collected and stored in natural or man made lakes.

Response Action: Actions that will be carried out during a drought as various drought trigger points are reached. Response strategies can include anything from short-term emergency aid to government assistance programs and media relations.

Response Planning: Addresses the conditions under which a drought induced water supply shortage occurs and specifies the actions that should be taken in response.

Risk: A combination of hazard, vulnerability, and exposure. Risk assesses the impact a hazard would have on people, services, facilities, and structures in a community and refers to the likelihood of a hazard event resulting in an adverse condition that causes injury or damage. Vulnerability As defined by FEMA’s risk assessment guidance (FEMA 386-2),

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.

vulnerability: Being open to damage or attack. Vulnerability is also defined as the likelihood that an area or sector will be negatively affected by environmental hazards (Bolin and Stanford, 1998).

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.