Oklahoma-Texas Drought Watch

The USGS Oklahoma-Texas Water Science Center continuously monitors the status of the principal rivers, reservoirs, and selected aquifers in both states. Stations with long-term continuous record are used to compare existing streamflows, reservoir storage, and ground-water levels with normal and extreme recorded values to measure the potential for drought, or the severity of an existing drought.

Definitions of Drought

Droughts do not have the same meaning or significance to all people. No generally accepted definition is adequate, nor is one practical, because drought is the result of many different factors. Three common definitions are:

Meteorological drought

A period of abnormally dry weather sufficiently prolonged for the lack of water to cause serious hydrologic imbalance in the affected area.1

Agricultural drought

A climatic excursion involving a shortage of precipitation sufficient to adversely affect crop production or range production.2

Hydrologic drought

A period of below average water content in streams, reservoirs, aquifers, lakes, and soils.3

Assessing Hydrologic Drought Severity

In general, when the water content in streams, reservoirs, aquifers, or soils falls below the long-term average, a pending or potential hydrologic drought may exist. The severity of a hydrologic drought is not always obvious until these water supplies are seriously depleted. The USGS network of long-term continuous record stations is important in measuring the severity of an existing or potential drought and making projections of subsequent drought conditions.

Oklahoma and Texas Drought Information

These are the primary resources for Oklahoma or Texas drought conditions and impacts.

U.S. Drought Monitor: Oklahoma

U.S. Drought Monitor: Texas

OWRB: Oklahoma Drought Monitoring

TCEQ: Texas Drought Information

TWDB: Texas Water Conditions

Current Hydrologic Drought

Map of below normal 7-day average streamflow compared to historical streamflow for the day of year.

Based on about 280 USGS sites in Texas having at least 30 years of record. The data used to produce this map are provisional. Click image to view larger, interactive version.

Surface-Water Conditions

USGS Resources


Current surface water conditions

Streams Reservoirs and Lakes


Below normal streamflow

By hydrologic unit By streamflow gaging station for the Nation

USGS Streamflow Statistics

Plot of 7-day average streamflow compared to historic conditions

Duration Graphs

USGS Vegetation Dynamics/Drought Viewer

Interactive map displaying multiple drought indexes

U.S. Drought Viewer

Comparison of Monthly Streamflow Maps

Select your comparison dates

Extreme Drought: September 1956

Flow condition map

Recent conditions: June 2018

Most recent flow condition map

Groundwater Conditions

USGS Resources


Data included in the USGS National Water Information System Database

All Texas Groundwater Data Real-time Data Daily Data Periodic Data


Active wells with over 10 years of record, where the most recent water-level measurement is below normal (below the 24th percentile of previous levels at that well)

Below Normal Groundwater Levels

Active wells whose levels reflect climatic variability and not human influences

Climate Response Network

All USGS GroundwaterWatch Networks

All Well Networks

Additional Resources

National Drought Mitigation Center

Texas Commission on Environmental Quality

Climate Conditions

USGS Resources


The USGS operates over 400 rainfall monitoring sites in Texas. However, these sites are for operational purposes. Routine inspections and other quality assurance measures are not performed that would make the data suitable for archival, retrieval, or interpretive uses; therefore, rainfall data will NOT be available for longer than a 120-day display period.

Precipitation Evapotranspiration

USGS Early Warning and Environmental Monitoring Program

US Rain Days/Consecutive Dry Days are computed daily, based on data from the National Weather Service.

U.S. Rain and Dry Days

Additional Resources

Texas Water Development Board

Texas Tech National Wind Institute

Texas Irrigation Technology Program

Office of the State Climatologist


A Historical Perspective on Precipitation, Drought Severity, and Streamflow in Texas during 1951–56 and 2011

By Karl E. Winters

U.S. Geological Survey Scientific Investigations Report 2013-5113

Effects of drought in central and south Texas: Chapter C in Drought in the Southwest, 1942-56

By H.E. Thomas

U.S. Geological Survey Professional Paper 372-C

Additional USGS Texas Publications

Drought Bibliography

Low-Flow Bibliography

References Cited

Drought text modified from Hanson, R. L., 1987, Base flow as an indication of drought occurrence. In: S, Subitzky (ed.), Selected Papers in the Hydrologic Sciences: U.S. Geological Survey Water Supply Paper 2330. pp. 115-129.

1 Huschke, R.E., ed., 1959, Glossary of meteorology: Boston, American Meteorological Society, 638 p.

2 Rosenberg, N.J., ed., 1979, Drought in the Great Plains- Research on impacts and strategies: Proceedings of the Workshop on Research in Great Plains Drought Management Strategies, University of Nebraska, Lincoln, March 26-28: Littleton, Colorado, Water Resources Publications, 225 p.

3 Yevjevich, Vujica, Hall, W.A., and Salas, J.D., eds., 1977, Drought research needs, in Proceedings of the Conference on Drought Research Needs, December 12-15, 1977: Colorado State University, Fort Collins, Colorado, 276 p.