Historical Data

Provisional data may be inaccurate due to instrument malfunctions or physical changes at the measurement site. Subsequent review based on field inspections and measurements may result in significant revisions to the data. Provisional data is subject to revision until they have been thoroughly reviewed and received final approval.

Data users are cautioned to consider carefully the provisional nature of the information before using it for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences.

Information concerning the accuracy and appropriate uses of these data or concerning other hydrologic data may be obtained from the EAA.

Daily high level historical data can be downloaded in CSV format using the following links:

Historical Daily Mean Springflow available from the U.S. Geological Survey using the links below.

Download Comal
Download San Marcos

This data may be is subject to change due to instrument issues or physical changes at the measurement site, which may result in significant revisions to the data. Data displayed here are subject to revision until they have been thoroughly reviewed and receive final approval. Questions? Contact us at info@edwardsaquifer.org

About Us

The Edwards Aquifer Authority is a groundwater district, mandated by the 1993 Edwards Aquifer Authority Act. The Act grants all of the powers, rights, and privileges necessary to manage, conserve, preserve, and protect the aquifer. The EAA regulates the portion of the Balcones Fault Zone Edwards Aquifer – a jurisdictional area that provides water to over 2.5 million people, and covers more than 8,000 square miles across eight counties. These include all of Uvalde, Medina, and Bexar counties as well as parts of Atascosa, Caldwell, Guadalupe, Comal, and Hays counties.