About the Plan

Our Vision

A healthy watershed that supports a clean, clear, and flowing San Marcos River for the future as it was in the past.

San Marcos River Watershed Overview

The Upper San Marcos River (USMR) segment (Segment 1814) spans 4.5 miles, extending from its headwaters at Spring Lake to its confluence with the Blanco River. The river is primarily spring-fed from the Edwards Aquifer and receives periodic inputs of stormflow from four major tributaries: Sink Creek, Sessom Creek, Willow Creek, and Purgatory Creek. This segment of the river is classified for contact recreation, exceptional aquatic life use, and a source of drinking water for downstream users. 

The San Marcos population is expected to increase by two to four percent over the next 20 years. In unique ecologic and hydrologic areas such as the USMR watershed, aiming to meet the growing demand for infrastructure through the implementation of sustainable and environmentally conscious development is more important than ever in order to protect this valuable resource from harmful pollutants reaching the water due to an increase in impervious cover.

A map of the Upper San Marcos River Watershed

Watershed Protection Plan (WPP) Background

In 2010, the Upper San Marcos River Watershed was cited on the Texas Commission on Environmental Quality (TCEQ)’s 303(d) list of impaired waters, for exceeding total dissolved solids (TDS) water quality standards. The watershed is currently in compliance with the Clean Water Act standards, but several pollutants have been identified as a concern by stakeholders. The Upper San Marcos River Watershed Protection Plan (USMR WPP) began in 2012 as a multi-year process of research and information gathering. In 2018, the plan became a TCEQ and United States Environmental Protection Agency (EPA) approved watershed protection plan.

View the Full Watershed Protection Plan (PDF)