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Upper San Marcos River: Developing a Watershed Protection Plan

The Meadows Center and Partners completed a watershed protection plan for the Upper San Marcos River Watershed in April 2018.


The headwaters of the Upper San Marcos River around Spring Lake are fed by springs from the Edwards Aquifer, a major source of drinking water for central and south-central Texas. Because surface water and groundwater are highly connected in this area, water quality in the aquifer is directly tied to water quality in the river and its tributaries. In 2010 and 2012, the Upper San Marcos River (Segment 1814) did not meet state water quality standards for total dissolved solids (TDS). The watershed is also experiencing significant population growth which is expected to continue over the next 20 years. Urbanization increases the volume of stormwater, and associated pollutants, that enter lakes, streams, and rivers.

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Project Description

In an effort to protect water quality and biodiversity, and recreation and economical benefits, the Upper San Marcos Watershed coordination group was formed to develop a watershed protection plan (WPP). The group, led by Texas State University – Meadows Center for Water and the Environment, consists of members from over 15 local entities.

They completed 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. As part of the watershed characterization, the Meadow's Center used existing water quality monitoring data, land use information, and results from additional targeted monitoring to determine how many nutrients each of the major pollution sources contributed to the lake.

Based on this information, the group and other watershed stakeholders identified management measures that could be used to prevent or mitigate nonpoint source pollution from each pollutant source, to be included in the WPP. The Upper San Marcos River WPP was accepted by the U.S. Environmental Protection Agency in April 2018 and has been in the implementation phase ever since.

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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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