Texas Water Conditions & Data

Texas has 23 river basins, including 15 major river basins and eight coastal basins, each with varying hydrological regimes and abilities to supply water.  Surface water is an important source of water for Texas.  In 2019, it accounted for nearly 42% of the 14.2 million acre-feet of water used in Texas (2022 State Water Plan).  Surface water is projected to account for 46% of the total water supply including the volume of new water from recommended strategies in 2070 (2022 State Water Plan)..  However, this critical water source faces several challenges in the coming years, including aging reservoirs which are filling with sediment and the lack of viable sites for new reservoirs.

The Surface Water Resources Division at TWDB is responsible for aiding water resources planning and management efforts by providing scientific data and engineering expertise in support of TWDB's statutory requirements (Texas Water Code §§16.012).  This is accomplished through the numerous data collection efforts listed below, a significant portion of which is made available to TWDB partners and customers, including citizens, state water planners, regulators, lake and reservoir owners, and other decision-makers via the agency website.  Additional data not hosted on the website is available upon request.

Water Data for Texas is a new effort by TWDB staff to provide a single access point for customers to receive water-related data.  At this time, Water Data for Texas hosts only Texas historical and current reservoir data, but staff is working to expand the website to include additional data related to bays and estuaries, drought, and groundwater.

Listing of Available Data Sources

Water Data for Texas landing page provides the most comprehensive information available of conditions in 122 major water supply reservoirs in Texas, as well as Elephant Butte, located in New Mexico. Information for three other reservoirs i.e., Addicks, Barker, and Natural Dam, that do not serve water supply functions, is also provided.  This represents 96% of the total conservation storage capacity of the 188 major water supply reservoirs in Texas.  By definition, a major reservoir has a conservation storage capacity of 5,000 acre-feet or greater.  To complete Water Data for Texas, TWDB compiled extensive records from federal, state, and local partners to generate current and historical information on reservoir levels, storage, surface area, and elevation-area-capacity curves.  In many cases, the website provides data for the entire history of the reservoir.

Texas Water Conditions Report is a monthly summary report describing statewide and regional conditions for 122 major water supply reservoirs, HUC runoff, soil moisture, rainfall, and 18 key groundwater monitoring wells.  More detailed information about the water supply reservoirs is available through Water Data for Texas.

Precipitation & Evaporation Data - Monthly and annual precipitation and evaporation rates are provided for each 1° quadrangle in Texas.  Precipitation data are available from 1940 while gross lake surface evaporation data are available beginning in 1954.

Drought - TWDB compiles data for six drought indices including, the Crop Moisture Index, Palmer Drought Severity Index, Standardized Precipitation Index, Keetch-Byram Drought Index, Reservoir Storage Index, and Streamflow Index.  This data is available from August 2009 to present.

Lake Surveys - TWDB's Hydrographic Survey Program collects bathymetric and sedimentation data on reservoirs throughout Texas.  Current elevation-area-capacity calculations and GIS data can be downloaded from the list of completed surveys.  Additional requests or questions can be submitted to hydrosurvey@twdb.texas.gov.

Coastal Hydrology - TWDB compiles estimates of freshwater inflows to Texas bays and estuaries.  Monthly and annual inflow summaries, beginning in 1941, are available on the website for the Sabine-Neches, Trinity-San Jacinto, Lavaca-Tres Palacios, Guadalupe, Mission-Aransas, and Nueces estuaries as well as the combined Upper and Lower Laguna Madre Estuary.  Inflow summaries for the Brazos River Estuary, San Bernard Estuary, East Matagorda Bay, and separated Upper Laguna Madre and Lower Laguna Madre also are available and begin in 1977.  More detailed hydrology requests can be submitted to coastal-data@twdb.texas.gov.

Estuary Monitoring/Datasonde Data - TWDB collects water temperature, conductivity, level, and salinity data every 60 minutes at select locations in all major and some minor estuaries in Texas, with some data extending back to 1986.  TWDB also occasionally collects dissolved oxygen, pH, and other parameters as part of special studies.  Data requests can be submitted to coastal-data@twdb.texas.gov.

Estuarine Hydrographic Studies - TWDB has conducted synoptic hydrographical surveys of all major Texas estuaries to obtain water velocity, water level, and water quality data in navigation channels and other representative bay locations over several tidal cycles.  Data from surveys collected between 1987 and 2003 are available on the website.