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Upper San Marcos River: Developing a Watershed Protection Plan

A Nonpoint Source Program (NPS) project to develop a Watershed Protection Plan (WPP) for the Upper San Marcos River Watershed.


The headwaters of the Upper San Marcos River around Spring Lake are fed by springs from the Edwards Aquifer. The Upper San Marcos River is on the TCEQ 303(d) List due to elevated concentrations of total dissolved solids (TDS). Development and changing land uses are presenting new pressures and additional water quality concerns related to bacteria, nutrients, and sediment.

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Project Description

The Upper San Marcos Coordination Group developed a watershed characterization and then a WPP to address the TDS impairment and the additional water quality concerns for the Upper San Marcos River, with a focus on Spring Lake. The first phase of the project was a watershed characterization using existing water quality monitoring data and land use information as well as the results from additional targeted monitoring. As part of the watershed characterization, Texas State University-Meadows Center calculated a nutrient budget for Spring Lake to determine the nutrient load contributed by each of the major sources flowing into the lake. The Meadows Center provided support to the Coordination Group in developing the watershed characterization and the WPP. The TCEQ accepted the WPP in April 2018.

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For More Information

To find out more about the NPS Program, call 512-239-6682 or e-mail us at

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