Water and drought play important roles in the Southwest's predominantly arid or semi-arid ecosystems. All biological organisms require water in order to function, and many of the region's animals and plants are well-adapted to the daily, seasonal, and annual cycles of this essential resource. Water serves critical roles in agriculture, industry, recreation, transportation, and maintenance of our environment, as well as our very quality of life.

Drought is a period of unusually persistent dry weather that lasts long enough to cause serious problems such as crop damage and/or water supply shortages. The severity of the drought depends upon the degree of moisture deficiency, the duration, and the size of the affected area (source: National Weather Service). A drought can be defined by the amount of precipitation in an area, by the amount of moisture in the soil, by surface and subsurface water supplies, or by water shortages affecting people.

Follow the links below and throughout the page to explore water and drought resources for the southwestern United States.

State Resources:

• Arizona's Sustainability of Semi-Arid Hydrology and Riparian Areas (SAHRA) organization promotes sustainable management of water resources in semi-arid regions, through stakeholder-driven interdisciplinary research, aggressive public outreach and strong education initiatives, leading to rapid dissemination and application of cutting-edge scientific knowledge.
• Nevada's Division of Environmental Protection's Bioassessment program provides information about biological indicators of watershed health.
• New Mexico Environment Department's Surface Water Quality Bureau monitors watersheds in the state using biological indicators on a 5-year cycle.
• The US Geological Survey (USGS) Water Resources and National Resources Conservation Service (NRCS) SNOTEL programs are national-level resources that also provide state-specific information.

Regional and National Resources:

• The Automated Geospatial Watershed Assessment Tool (AGWA) is a GIS-based hydrologic modeling tool available for download.
• The Drought Impacts on Regional Ecosystems Network (DIREnet) is an association of researchers and land managers interested in documenting impacts on major ecosystems of the western United States resulting from drought-related processes.
• The Lower Colorado River Aquatic Gap Analysis Project examines the current level of aquatic biodiversity within a system to identify gaps in distribution and protection of species so managers, planners, scientists, and policy makers may use these data to make better-informed decisions or to focus future research.
• The National Integrated Drought Information System (NIDIS), implemented by the National Oceanic and Atmospheric Administration (NOAA), provides an integrated drought monitoring and forecasting system at federal, state, and local levels, including an "early warning system."
• The Vegetation Drought Response Index (VegDRI) is a valuable addition to the field of drought monitoring, with applications for the agricultural community. VegDRI, updated biweekly, combines information from historical and current satellite observations, climate indicators, ecological settings, and soil characteristics to show drought's effect on vegetation.
• The USGS has Biomonitoring of Environmental Status and Trends (BEST) reports available for the Columbia, Mississippi, and Rio Grande River basins that analyze the environmental contaminants and associated fisheries impacts for these major river basins of the West.