Additional Resources

The Water Cycle
US Global Climate Change Research Program

The following pages contain information on surface water, ground water, water quality, drought, and snowpack in the Southwest.

USGS Water Science by State:

NIDIS and NOAA Drought Information:

NRCS SNOTEL (SNOwpack TELemetry) Data by State:

Water and Drought

2006 Flood Damage at Coronado National Memorial, Arizona
National Park Service, Coronado National Memorial

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:

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.

Southwest Water and Drought Datasets
Showing 10 of 13 ( Show All )
CollapseArizona Ground-Water Climate Response Network
Description: The USGS maintains a network of wells to monitor the effects of droughts and other climate variability on ground-water levels. These web pages integrate site information from NWISWeb, location maps, and ground-water hydrographs. For wells in Arizona with five or more years of daily record, the daily values are plotted on a background of the historical minimum, maximum, and median measurements for each day. The data used in the statistics can be viewed in a table or retrieved as a tab-delimited file. Statistics are based on the final, approved daily values, and each hydrograph lists the number of values upon which the statistics are based. Recent data presented in these hydrographs have not yet been approved and are termed "provisional data". These data are not considered final until they are approved by the USGS Director, usually in April or May for the previous water year ending on September 30. There are three types of data available from wells measured by the USGS: 1. "periodic data", which are ground-water levels measured manually at selected intervals, usually with a steel or electric tape. These measurements typically are made from once per week to once per year. 2. "continuous data", which are ground-water levels measured by an automatic sensing device, recorded by data loggers, and retrieved periodically from the field. The availability of these data may lag current conditions by one to several months because they must be retrieved from the field, processed, and loaded into the database. 3. "real-time data", which are continuous data that are transmitted from the field to the USGS at least once per day. Barring occasional equipment malfunctions, these data reflect current ground-water conditions at the well. The Climate Response Network pages serve ground-water level data from selected wells. These pages do not serve all of the wells monitored by the USGS in each state. Additional well data from each state are available from NWISWeb, which contains data from about 800,000 wells across the United States and Puerto Rico.
Resource Type: Datasets
Resource Format: URL
Publisher: United States Geological Survey
ExpandColorado Ground-Water Climate Response Network
ExpandGeophysics of Rio Grande Basins
ExpandNevada Ground-Water Climate Response Network
ExpandNew Mexico Ground-Water Climate Response Network
ExpandRio Grande Basin Initiative: Texas/New Mexico Interactive County Maps
ExpandRio Grande Project Rio Grande Project Water Operations Data
ExpandRio Grande Real Time Data Collection Platform ( DCP ) data
ExpandSustainable Agricultural Water Conservation in the Rio Grande – Maps and Data
ExpandUnited States Geological Survey Real Time Flow Data for Colorado (by Major River Basin)
Southwest Water and Drought Agencies
Showing 10 Results
CollapseColorado State Cooperative Extension
Description: Search topics on this site such as crops/soils, drought/fire, food/nutrition or water resources. Use the AnswerLink feature on the site to search hundreds of frequently asked questions, or ask a new question.
Resource Type: State Government Agencies (U.S.)
Resource Format: URL
Publisher: Colorado State University, Cooperative Extension
ExpandLower Colorado River Giant Salvinia Task Force
ExpandLower Colorado River Giant Salvinia Task Force
ExpandMiddle Rio Grande Activities
ExpandRegion 6: Water Programs, Ecosystems Protection Branch
ExpandRiver Network
ExpandSouth Central Regional Center - National Wildlife Federation
ExpandThe Conservation Fund
ExpandUnited States Army Corps of Engineers-Nashville District.
ExpandUnited States Environmental Protection Agency Region 6 Water Programs

U.S. Environmental Protection Agency: Surf Your Watershed

The U.S. Environmental Protection Agency's "Surf Your Watershed" program integrates environmental information available by geographic units including state, watershed, county, metro area, and tribe.

The site provides access to three main databases:
1. Adopt Your Watershed, a database of watershed groups,
2. Wetlands Restoration Projects, which displays ongoing wetlands restoration,
3. Environmental Websites Database, a directory of websites dedicated to environmental issues and information.

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USGS Aquatic GAP Program

GAP Logo
[Copyright: USGS GAP Analysis Program]

The goal of the GAP Analysis Program is to keep common species common by identifying those species and plant communities that are not adequately represented in existing conservation lands. Common species are those not currently threatened with extinction. By identifying their habitats, GAP Analysis gives land managers and policy makers the information they need to make better-informed decisions when identifying priority areas for conservation.

Regional Projects:


National Water Quality Assessment (NAWQA) Program

NAWQA image
[Image: U.S. Geological Survey]

About the NAWQA Data Warehouse:
The USGS began its NAWQA program in 1991, systematically collecting chemical, biological, and physical water quality data from 42 study units (basins) across the nation. The Data Warehouse contains and links the following data:

  • Chemical concentrations in water, bed sediment, and aquatic organism tissues for about 2000 chemical constituents
  • Biological community data for 16,000 fish, algae and invertebrate samples
  • Site, basin, well and network characteristics with many descriptive variables
  • Daily stream flow information for fixed sampling sites
  • Ground water levels for sampled wells
  • 7,600 surface water sites and 8,100 wells
  • 49,000 nutrient samples and 31,000 pesticide samples as well as 9,000 VOC samples
  • 2,500 samples of bed sediment and aquatic organism tissues


The NBII Program is administered by the Biological Informatics Program of the U.S. Geological Survey
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