Evaluation of Augmentation Methodologies in Support of In-Situ Refugia at Comal and San Marcos Springs, Texas

Author LBG-Guyton Associates, BIO-WEST, Inc., Espey Consultants, Inc. and URS Corp
Year 2004
Description Evaluation of different augmentation methodologies to maintain habitats in Comal and San Marcos Springs during drought conditions
Publisher LBG-Guyton Associates
Location Comal Springs, San Marcos Springs
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The study was performed to investigate the feasibility of augmenting flow at Comal and San Marcos springs. Augmenting springflow was evaluated for the purpose of maintaining critical habitat for threatened and endangered species for a very limited period of time during drought conditions. The study was completed in June 2004 by a team led by LBG-Guyton Associates.

[From the Introduction]
The objective of this study was to investigate updated options that would complement the objectives of the regional pumpage reduction programs. In essence, the results of this project would maintain viable habitat long enough for the rains to return. To accomplish this goal augmentation strategies would need to be “custom designed” for each spring. This required a more detailed evaluation of:

  • The hydrogeology of the Comal Springs and San Marcos Springs areas, including a better understanding of how the springs and associated lakes changed under different flow regimes
  • The distribution of the endangered species in the springs and lakes
  • The different strategies that either added water to the springs to help prevent rapid decreases of flow over time or focused the available flow to the most critical areas so as to maintain suitable conditions.

This document addresses three areas:

1. The hydrogeology and hydrology of Comal and San Marcos Springs,

2. The location of the highest quality habitat in the spring complexes, and,

3. The use of additional waters to supplement the natural flows at the springs.

This report does not offer a single final answer, but does prioritize recommendations as to how the Authority might proceed toward a possible solution.