The Edwards aquifer, a regionally-extensive carbonate aquifer in Central Texas, is the sole source of water for nearly two million people, including the City of San Antonio. Pumpage from this aquifer is jeopardizing springflow from Comal Springs (in New Braunfels, Texas) and San Marcos Springs (in San Marcos, Texas), two of the largest springs in the state. These springs provide a habitat for a number of endangered species, and are an integral part of the local economies and the overall distribution of water in Central Texas. For these reasons it is important that flow from these springs be maintained, either through aquifer management plans that limit the withdrawal and usage of water from the aquifer, or through physical augmentation of the springs. In this thesis, the feasibility of maintaining springflow by augmenting discharge from the springs is investigated. Five potential methods of springflow augmentation (enhanced recharge, subsurface flow barriers, direct addition of water to the spring lakes, injection wells, and infiltration galleries) are presented and described. Based on present knowledge of the springs, the effectiveness of each method is evaluated, and the uncertainties associated with each are discussed. Computer models of the aquifer in the vicinity of the springs are constructed and used to model the effects of two of the augmentation methods (injection wells and infiltration galleries) on aquifer levels and spring discharges. The model results are used to estimate the efficiency of each of these methods and to develop general trends related to how the aquifer responds to the introduction of water through wells and infiltration galleries. Based on model results and the hydrogeology of each spring, an assessment of the each of the augmentation methods is presented, and recommendations are made as to the appropriateness of the various technologies at each spring.

"One of the world's great karstic aquifer systems, the Edwards aquifer system supplies water for more than 2 million people and for agricultural, municipal, industrial, and recreational uses. This volume reviews the current state of knowledge, current and emerging challenges to wise use of the aquifer system, and some technologies that must be adopted to address these challenges"--

This text explores the natural history of Texas and more than 2900 springs in 183 Texas counties. It also includes an in-depth discussion of the general characteristics of springs - their physical and prehistoric settings, their historical significance, and their associated flora and fauna.